Dissertations / Theses on the topic 'Naphthoic acid'

Polycyclic aromatic hydrocarbons (PAHs) are compounds containing carbon and hydrogen atoms of fused benzene rings in linear, angular or cluster arrangements. These compounds have a large (negative) resonance energy, resulting in a thermodynamically stable structures. PAHs may also contain alkyl- and nitro-substituent groups. The complexity in these molecules can be generated by substituting the aromatic carbon atom with nitrogen, oxygen or sulfur, giving rise to heterocyclic PAHs.

Deposition of metal naphthenates in process facilities is becoming a huge problem for petroleum companies producing highly acidic crudes. In this thesis, the main focus has been towards the oil-water (o/w) interfacial properties of naphthenic acids and their ability to react with different divalent cations across the interface to form metal naphthenates.

The pendant drop technique was utilized to determine dynamic interfacial tensions (IFT) between model oil containing naphthenic acid, synthetic as well as indigenous acid mixtures, and pH adjusted water upon addition of different divalent cations. Changes in IFT caused by the divalent cations were correlated to reaction mechanisms by considering two reaction steps with subsequent binding of acid monomers to the divalent cation. The results were discussed in light of degree of cation hydration and naphthenic acid conformation, which affect the interfacial conditions and thus the rate of formation of 2:1 complexes of acid and cations. Moreover, addition of non-ionic oil-soluble surfactants used as basis compounds in naphthenate inhibitors was found to hinder a completion of the reaction through interfacial dilution of the acid monomers.

Formation and stability of metal naphthenate films at o/w interfaces were studied by means of Langmuir technique with a trough designed for liquid-liquid systems. The effects of different naphthenic acids, divalent cations, and pH of the subphase were investigated. The results were correlated to acid structure, cation hydration, and degree of dissociation, which all affect the film stability against compression.

Naphthenic acids acquired from a metal naphthenate deposit were characterized by different spectroscopic techniques. The sample was found to consist of a narrow family of 4-protic naphthenic acids with molecular weights around 1230 g/mol. These acids were found to be very o/w interfacially active compared to normal crude acids, and to form Langmuir monolayers with stability depending on the aqueous pH. At high pH, addition of Ca²⁺ increased the film stability due to formation of calcium naphthenate at the surface.

A new experimental setup based on near infrared spectroscopy was used to monitor the formation, growth, and inhibition of calcium naphthenate particles in o/w systems. This method was found to be suitable for studies of particle formation rate and growth qualitatively under different experimental conditions.

Naphthenic acids (NAs) are oil-derived mixtures of carboxylic acids and are aquatic contaminants of emerging concern. The objective of the research presented in this thesis was to investigate the toxicity of NAs in tadpoles of the frog Silurana (Xenopus) tropicalis. Using electrospray ionization high-resolution mass spectrometry (ESI-HRMS), I determined that the proportions of O2 (presumably carboxylic acid moiety) species were 98.8, 98.9 and 58.6% respectively, for two commercial extracts (S1 and S2), and acid extractable organics (AEOs) from oil sands process-affected water (OSPW). The rank order potency based on the lethal concentration fifty (LC50) and effect concentration fifty (EC50) with and without normalization for the quantity of O2 species was S1 > S2 > AEO. The main effects observed were reduced body size, edema, and cranial, cardiac, gut and ocular abnormalities. Oligonucleotide microarray technology was used to determine the transcriptomic responses in developing S. tropicalis embryos following exposure to S1 and S2 at a sub-lethal concentration of 2 mg/L. Some of the significantly enriched pathways (p < 0.05) included metabolism and cell membrane depolarization, and some were related to observed abnormalities including edema, gastrointestinal system, and cartilage differentiation. I established and validated a derivatization method for NAs using pentafluorobenzyl bromide (PFBBr) prior to gas chromatography-electron impact mass spectrometry (GC-EIMS) to increase chromatographic resolution, and sensitivity, compared to boron trifluoride-methanol (BF3/MeOH) and N-tert-Butyldimethylsilyl-N-methyltrifluoroacetamide (MTBSTFA). Solid-phase microextraction of volatiles originating from S1, S2, Merichem NAs and an AEO mixture led to the identification of 54, 56, 40 and 4 compounds, respectively. The compounds identified in the mixtures included aliphatic and cyclic hydrocarbons, carboxylic acids, alkyl-benzenes, phenols, naphthalene and alkyl-naphthalene, and decalin compounds. To determine the chemical nature of the toxic compounds in NA mixtures, the S2 and AEOs preparations were fractionated using open column chromatography. A non-polar and a polar fraction were obtained from S2. Overall, the toxicity of the polar fraction was not significantly different from whole S2 (p > 0.05). Six fractions of AEOs were obtained, however because of limited material, only the toxicities of F3 and F4 were assessed. The toxicity of F3 was significantly lower than AEOs (p < 0.05) and F4 was not toxic for S. tropicalis (p > 0.05). These results suggest that during fractionation, toxic compounds were lost or that the toxicity of AEOs results from the combined effects of the compounds present in the whole extract. The toxicological dose descriptors, morphometric, transcriptomic and chemical analysis herein presented may contribute to the development of environmental guidelines for NAs and AEOs.

Naphthenic acids (NAs) are carboxylated alkanes and cycloalkanes concentrated in wastewater during oil sands processing. The general chemical formula is C{n}H{n+Z}O{2}, where n represents the number of carbon atoms and Z specifies a homologous family with 0-6 rings (Z=0 to Z=-12). The wastewater is acutely toxic to surface water organisms and is stored in tailings ponds with over 230 million m³ of fines tailings and free water. The purpose of this thesis was to provide a preliminary evaluation of the potential attenuation of NAs during groundwater flow from the ponds. Laboratory studies were conducted to evaluate possible attenuation mechanisms. Aerobes from aquifer material degraded 60% of the NAs over 20 weeks in laboratory microcosms. The greatest decrease occurred in the low molecular weight bicyclic homologues with 12 to 16 carbons. The microbial activity confirms that aerobic naphthenate-degrading bacteria occur naturally in the glacial aquifer near Suncor's Pond 2/3. These results support the hypothesis that limited aerobic biodegradation of the smaller components of NAs could occur relatively rapidly under field conditions. There was no measurable decrease in NA concentration over six months in anaerobic microcosms, although microbial activity did lead to sulfate-reducing and methanogenic conditions. The theoretical retardation in glacio-fluvial sands was calculated using soil-water partitioning coefficients (K{d}) determined by batch equilibration experiments using a mixture of naturally occurring naphthenic acids as well as the nine surrogates. The retardation (porosity of 0. 3, bulk density of 1. 5 g/mL) ranged from 1. 2 to 2. 6. However, no measurable sorption was seen at the field sites. Detailed characterization allows us to examine how the proportions of homologue, or groups of molecules with the same molecular weight and number of cycloalkane rings, vary. Aerobic biodegradation favoured removal of low molecular weight NAs. A 15% mass loss attributed to sorption caused no changes in the 3D signature. Thus, changes in NA "signature" in groundwater systems were then attributed to aerobic biodegradation. Three plumes were examined for evidence of attenuation of NAs via biodegradation. First, the individual samples were classified as background, possibly process-affected or process-affected using a combination of Piper diagrams, the stable isotopes oxygen-18 and deuterium, dissolved chloride and sodium, as well as the total naphthenic acids concentration. Second, in order to estimate attenuation due to dispersive dilution, a linear correlation line was drawn between various conservative tracers and the naphthenic acids concentration. This allowed the identification of certain samples as possibly having a lower concentration of NAs than could be expected from simple dispersive dilution. Third, the 3D signature of certain samples were examined for the presence of the aerobic biodegradation 3D signature. One site showed good evidence for aerobic biodegradation of naphthenic acids. A second site showed some evidence for biodegradation under methanogenic conditions but the evidence was not definitive. The evidence at the third site was contradictory and no conclusions could be drawn from it. This research suggests some attenuation of NAs by biodegradation may be possible during groundwater flow.

Neuroendocrine processes coordinate the behavioural, physiological, and seasonal aspects of reproduction. Some chemicals can disrupt the hypothalamus-pituitary-gonadal axis, impacting reproductive health. Naphthenic acids (NAs), the carboxylic acids in petroleum, are of emerging concern as they contaminate coastlines after oil spills and aquatic ecosystems of the Athabasca oil sands area. They are acutely toxic in fish and tadpoles and possibly endocrine disrupting at sublethal levels. I characterized courtship behaviours and disruption by NAs in the Western clawed frog, Silurana tropicalis. Courtship primarily consists of males producing low trills and achieving amplexus, a mating position where a male clasps a female. Adult frogs were exposed for five days to 20 mg/L NA, a dose low enough to not affect physical activity. In males, absolute calling activity was reduced. Other acoustic parameters such as dominant frequency, click rate, and trill length were not affected. Injecting human chorionic gonadotropin had a slight rescue effect. Vocalization and amplexus were both inhibited after exposure and restored after 2 weeks of recovery. However, calling behaviour did not predict competitive ability or mating success. In females, NA exposure reduced mating success, possibly through decreased attractiveness or receptivity. Receptivity can be indicated by attraction towards the sound of mating calls (phonotaxis), which is cryptic and subjective. I created an apparatus that measures phonotaxis by placing speakers inside traps with infrared lights to detect the time of entry. This novel method is widely applicable for low-visibility observations and studies of choice and preference. This work shows that an aquatic contaminant can reduce mating success in otherwise healthy frogs, and provides a detailed foundation for further investigation.

Naphthenic acids (NAs) are carboxylic acids found in crude oil and petroleum products. The objectives of the research presented here were to: a) assess the occurrence and fate of NAs in crude oil and refinery wastewater streams; b) evaluate the biotransformation potential and inhibitory effects of NAs under nitrifying, denitrifying and methanogenic/fermentative conditions; c) investigate the factors affecting NA biotransformation under aerobic conditions and the microbes involved; and d) assess the toxicity of individual model NAs using quantitative structure-activity relationships (QSAR) and examine the effect of structure on NA biotransformation potential. NAs are ubiquitous in refinery wastewater streams and the desalter brine was found to be the main source of NAs in refinery wastewater. A commercial NA mixture was not biodegraded under nitrate-reducing or methanogenic/fermentative conditions. NAs were degraded under aerobic conditions by an NA-enriched culture; however, a residual fraction was not degraded under all conditions studied. The results indicated that NAs are not inherently recalcitrant and the residual fraction was due to the individual NA concentrations being below the minimum substrate concentrations at which they are no longer degraded. A fraction of the NA mixture was completely mineralized to carbon dioxide, with the remaining portion biotransformed to more oxidized intermediates. Overall, the results indicated that NAs were degraded under aerobic conditions; however, biological treatment of NA-bearing wastewater will not completely remove NA concentrations and thus, biological treatment must be combined with physical/chemical treatment to achieve complete NA removal.

Naphthenic acids are a family of carboxylic acids that are found in oil sands bitumen. These compounds partition to the aqueous phase during extraction and refining and are toxic to various biota. The removal of these acids from solution is difficult due to their low concentrations, complexity of the mixture and poor understanding of the behaviour of the mixed compounds. In particular, partitioning of these organic acids to solid surfaces is not well understood. Knowledge of this equilibria would be helpful for potential process development. The research presented here describes the adsorption of two surrogate naphthenic acids onto inorganic minerals (copper sulphide and copper hydroxide). Decanoic acid and cyclohexane pentanoic acid were found to be insoluble in water at pH 3, leading to hydrophobic adsorption onto the minerals and the reaction vessel surfaces. At pH 8.5, both acids formed insoluble copper-carboxylate complexes when mixed with the minerals. The hypothesized 2:1 acid:copper stoichiometry was confirmed. The mechanism of complexation varied with the reaction conditions; both chelating and bridging complexes were observed in the resultant metallo-organic solids. The relative hydrophobicity of the two NA surrogates was also found to contribute to the different adsorption trends. During the pH 8.5 reactions, the solution pHs were found to drop. The uncontrolled decreases in pH had significant effect on the water-solid partition and on the apparent mineral loading of the organics. It appears that soluble copper cations have a higher extent of reaction with the carboxylate anions than does copper contained in the mineral solids. Quantification of these reactions is difficult; however this research does enable conclusions about how the organic acids and inorganic minerals interact and sets the stage for future research.

The sustained high price of crude oil is increasing the viability of producing oils and tarry bitumens which have high acid contents and which would have been uneconomical to produce previously. The acidity of these oils is due to the presence of a class of compounds known as Naphthenic Acids (NAs) which are thought to arise from the biodegradation of some of the crude oil hydrocarbons. Some oils contain as much as 3% by weight NAs. The acids cause engineering and production difficulties through corrosion of refinery plant and deposition as salts in pipelines. NAs also cause environmental problems because they are known toxicants. For example, the processing of the vast tar sands deposits of Alberta, Canada results in tailings pond waters containing very high concentrations of NAs. The ponds are estimated to exceed a billion m3 by 2025 and are already visible from space. Bioremediation is an attractive option for reducing the toxicity of such NA wastes. However, an understanding of the biodegradation potential of NAs has previously been hindered by the lack of knowledge of the molecular structure of individual NAs and by the lack of appropriate suitable surrogate acids for detailed mechanistic studies. Although it is known that NAs are complex mixtures of alkyl substituted, mainly alicyclic, carboxylic acids fitting the general formula C H2 _ZO2, where Z denotes the hydrogen deficiency resulting from ring formation, beyond this, comparatively little was known of NA chemistry, prior to the present study. The current study describes the synthesis of a series of novel monocyclic surrogate NAs containing both alkyl and alkanoate side-chains (viz: butylcyclohexylbutanoic acids, BCHBAs). The branching in the butyl chain was varied in a systematic way from nthrough sec-, iso- and tent-butyl. The surrogates were synthesised in high purity (>94%) and rigorously characterised at each synthetic stage by various spectroscopic techniques. A toxicity assay in which developing oyster (Crassostrea gigas) embryos were inoculated with the individual monocyclic surrogate NAs demonstrated EC50 (Effective Concentrations for 50% of population) values ranging from 0.11 mg L1 to 0.49 mg L'. The results exhibited a clear quantitative structure-activity relationship (QSAR) between the degree of branching in the alkyl chain and the toxic effect, with the less branched NAs exhibiting the highest toxicity. A detailed biodegradation study of the monocyclic surrogate NAs was made. Again a clear QSAR was established. In this instance, n-BCHBA was the most readily degraded with 97% degradation by day 9, and tert-BCHBA the most resistant with only 2% degradation by day 30, whereas iso-BCHBA and sec-BCHBA were 77% and 53% degraded after 30 days, respectively. The degradation of the monocyclic surrogate NAs proceeded with the production of major metabolites consistent with ß-oxidation of the alkanoic acid side chain. The metabolites were tentatively identified by mass spectrometry as the ethanoic acid analogues of the butanoic acids. These resisted further biodegradation. That biodegradation proceeded via 8-oxidation was confirmed by the synthesis and subsequent biodegradation experiments with iso-butylcyclohexylmethylbutanoic acid, where the iv additional methyl branch in the butanoic acid side chain effectively halted biodegradation. The QSAR observed in the toxicity and biodegradation experiments is thought to be related to the hydrophobicity of the individual NA surrogates, which determines their bioavailability. These results with surrogate compounds help to explain previous reports of the biodegradation of natural NAs in which reductions in toxicity during initial biodegradation have been observed. The surrogate NAs synthesised herein were also used to devise a unique derivatisation procedure which then facilitated the analysis of synthetic and natural NAs by liquid chromatography-multistage mass spectrometry (LC-MS°). Analysis of the resulting naphthenic amides (NAds) allowed an improvement in detection of over two orders in magnitude by positive ion electrospray ionisation-mass spectrometry (ESI-MS) compared to negative ion ESI-MS. The improved response allowed multistage LC-ESI-MS° experiments to be carried out and detailed mass spectral fragmentation pathways for individual NAds to be deduced. Analysis of derivatised natural NA mixtures then allowed a more detailed molecular characterisation of individual NAs than has been possible hitherto. The use of the surrogate NAs synthesised herein has thus improved significantly our understanding of NA chemistry and the influence of NA structure on the potential for NA bioremediation.

The remediation of tailings water, a by-product of bitumen extraction, is of utmost importance to the Athabasca oil sands industry due to its toxicity to aquatic environments. Naphthenic acids (NAs), natural components of bitumen, are the major contributor to the toxicity of tailings water. The use of algae for remediation of tailings water is a new approach to reduce the toxicity of tailings water. The combined extracted NAs and algal oils can potentially be used as a low cost feedstock for the production of biodiesel. In this study, the feasibility of using NAs for the production of biodiesel was investigated using mixtures of canola oil and commercial NAs as model compounds. Since NAs are a mixture of cyclic and acyclic carboxylic acids, the acid-catalyzed esterification of NAs without canola oil was investigated. The acid-catalyzed esterification reaction was carried out with methanol, and the influence of variables affecting the esterification process was examined. The experimental results showed that increasing temperature and catalyst concentration increased the reaction rate and final conversion of NAs to their corresponding methyl esters. The catalyst study showed that sulfuric acid had a more positive effect on the esterification reaction compared to p-toluene sulfonic acid. Additionally, an excess methanol:oil ratio had a negative effect on the esterification reaction due to the solubility of NAs in methanol. The acid-catalyzed transesterification/esterification of mixtures of NA and vegetable oil (canola oil along with 5% NAs) with methanol was investigated at different operating conditions. The outcomes of these experiments showed that increasing temperature, sulfuric acid concentration, and methanol content had positive effects on the rate of reaction and final ester products. The general conclusion of the thesis is that the conversion of NAs to useful products is indeed feasible and can be part of the solution to tar sands tailing pond remediation.

Thesis (M.Math)--University of Waterloo, 2004.
"A thesis presented to the University of Waterloo in fulfillment of the thesis requirement for the degree of Master of Science in Earth Sciences. Includes bibliographical references.

In recent years the production of crude oils with high amounts of naphthenic acids has increased. Certain problems are related to this type of crudes and a better understanding of the chemistry of the naphthenic acids is therefore of interest.

Synthetic model naphthenic acids, as well as commercial mixtures and crude oil naphthenic acids have been utilized to study the chemistry of naphthenic acids. Partitioning of naphthenic acids between oil and water and the dissociation equilibria in water have been studied in addition to their interfacial tension and micellisation behaviour.

A method for studying the precipitation of calcium naphthenate particles by means of near infrared spectroscopy was presented. It was shown that the method gives information about the induction period and about the rate of reaction for particle growth. Solubility products can also be estimated.

Near infrared spectroscopy were also utilized to study the ability of naphthenic acids and other amphiphiles to disintegrate asphaltene particles. It was shown that the structure of the naphthenic acids is important and that a commercial mixture of different surfactants had the best disintegration effect. The technique is applicable for screening the efficiency of various additives as disaggregation chemicals.

Emulsion stability was studied by means of Langmuir technique, critical electric field and bottle tests. The Langmuir study showed that the presence of Ca2⁺-ions at elevated pH gave rise to stable naphthenate monolayers. Oil/water emulsions stabilized with different carboxylic acids were investigated at different pH-levels and water-contents. It was demonstrated that water/oil emulsions could be stabilized by a combination of multilayer (D-phase) and asphaltene particles. Critical electric field was used to determine the emulsion stability of these systems and it was shown that a combination of 60% asphaltene particles and 40% D-phase gave the stablest w/o-emulsions. This investigation verifies the importance of D-phase stabilization in combination with asphaltene particles in systems with acidic heavy crude oil (including bitumen) and water.

Paper III and VI reprinted with kind permission of Elsevier, sciencedirect.com

Amongst the polar organic compounds occurring in unrefined and refined crude oils and the associated polluted production waters, complex mixtures of acids, known historically as naphthenic acids (NAs), have achieved prominence. This is particularly because NAs have been designated a toxicant class of concern in the oil sands process-affected water (OSPW) that has accumulated in vast quantities following exploitation of the oil sands of Northern Alberta, Canada in recent years. However, though there have been calls for NAs to be added to pollutant inventories, at the initiation of the current study, little knowledge existed of the exact composition of refined or unrefined NAs. The overall aim of the current study was therefore to identify individual NAs in refined (commercial) and unrefined (e.g. oil sands process-derived) complex mixtures of acids and then to assess the toxicity of any identified NAs. Individual NAs were tentatively identified by interpretation of the electron ionisation mass spectra of methyl ester derivatives, following comprehensive multidimensional gas chromatography-mass spectrometry (GCxGC-MS). Reference acids were then either purchased, or more commonly, where they were not commercially-available, synthesised, mainly by micro-hydrogenation methods, for co-chromatography and comparison of mass spectra of methyl esters with those of unknowns. The synthetic NAs, purified to >97% were then subjected to toxicological assessments using the Microtox™ assay. In all, 34 compounds were obtained pure enough for testing. Microtox results revealed that the toxicity endpoint (50% Inhibition Concentration, IC50) was between 0.004 and 0.7 mM. Exponential and other correlations were noted between carbon number and toxicity in several of the structural groups of acids assayed, which may be beneficial for predictions of toxicity of non-synthesised acids. Although n-hexanoic acid (IC50 0.7 mM) had the lowest toxicity, adamantane-type acids were the least toxic as a group overall. Conversely, the decahydronaphthalene (decalin)-type acids had the largest range of toxicities (IC50 0.004 to 0.3 mM) and the most toxic acid assayed was 3-decalin-1-yl-propanoic acid. According to USEPA guidelines many individual acids can be said to show low to medium toxicity. Since the acids in commercial and unrefined NAs occur in complex mixtures, an attempt was also made to assess mixture toxicity. Mixtures of individual structural groups of acids (e.g. acyclic isoprenoid acids, n-acids) and a mixture of all 34 acids were assessed. Apart from the adamantane sub-group of acids, all of the mixtures showed toxicities lower than the sum of the parts when calculated using equations for Concentration Addition and Model Deviation Ratios (simply the predicted IC50/Observed IC50). A hypothesis that achievement of a critical micelle concentration is required to produce toxicity was proposed to explain the lower than expected results. Some of the mass spectra of NA present in the commercial and unrefined mixtures were inconsistent with those of any of the alicyclic acids synthesised or purchased. These were hypothesised to be aromatic acids. Fractionation experiments of the NA mixtures using silver ion thin layer chromatography and solid phase extraction (Ag+TLC and Ag+SPE) were carried out in order to provide further evidence for aromatic acids. Ag+TLC allowed separation of a methylated NA mixture from OSPW into three distinct fractions; Ag+SPE resulted in eleven fractions, through the use of a wider range of solvents and differential solvent ratios. Analysis of the fractions by GC-MS revealed that each fraction was largely still made up of unresolved acids (as esters), although one or two fractions revealed some resolved acids. Use of averaged mass spectra and mass chromatography on each fraction revealed further resolved chromatographic peaks and associated interpretable mass spectra. Each of eight of the eleven sub-fractions were examined by GC-MS, in some cases by GCxGC-MS, and all by infrared spectroscopy, ultraviolet visible spectrophotometry and elemental analysis. A number of structures were proposed for the aromatic acids, including those with sulphur-containing moieties. It was noted that far from being minor components, aromatic acids comprised ca.25-40% of the OSPW acid extracts.

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O petróleo ainda continua sendo a maior fonte de energia não renovável do planeta. No seu estado bruto tem pouca utilidade. No entanto, seus derivados apresentam alto valor econômico. Nas etapas de processamento primário do petróleo alguns compostos de ocorrência natural são indesejáveis, como os ácidos naftênicos, resinas, asfaltenos, compostos sulfurados e metálicos. O poder corrosivo dos ácidos naftênicos preocupa as indústrias petrolíferas devido ao prejuízo causado nas tubulações e refinarias. Estudos recentes indicam que uma parcela desses ácidos quando submetidos a elevadas temperaturas (>280°C) pode sofrer reações de descarboxilação e degradação térmica, originando dióxido de carbono (CO2) e ácidos de cadeias menores como produtos de degradação. Os ácidos de cadeias menores juntamente com os ácidos naftênicos que se mantiveram preservados são corrosivos e o CO2 ao entrar em contato com água forma o ácido carbônico (H2CO3), podendo contribuir nas taxas de corrosão nos equipamentos do refino. Assim, o presente trabalho consistiu no desenvolvimento de uma metodologia para quantificação online do CO2 liberado no processo de destilação de petróleo. A metodologia desenvolvida foi baseada na técnica de microcromatografia gasosa. Os dados quantitativos de concentração de CO2 gerados pela microcromatografia foram relacionados com os valores de temperaturas de destilação, obtendo-se assim uma variação na concentração de CO2 de acordo com a temperatura de destilação do óleo. Com os resultados obtidos observou-se que para todos os petróleos destilados houve uma tendência na formação do gás CO2 partir de temperaturas superiores a 200°C. Na tentativa de elucidar a possível origem deste gás, supôs um mecanismo de descarboxilação para tais ácidos

A plume of process-affected groundwater was identified in a shallow sand aquifer adjacent to a tailings impoundment at Syncrude Canada Ltd. Quantitative and qualitative Naphthenic Acid (NA) analyses were performed on groundwater samples to investigate NA fate and transport properties in the subsurface. Analysis of dissolved organic and inorganic components was undertaken to identify, quantify and assess the mobility of other dissolved components of environmental significance. NAs at concentrations up to 87 mg/L were found to represent the major contributor to aquatic toxicity. Attenuation of NAs by biodegradation is not observed based on screening techniques developed to date. Retardation of NAs observed at the field scale, is consistent with weak sorption observed in the laboratory by other authors. Concentrations of ammonium approached 4 mg/L in the plume, however mobility is limited by cation exchange. Aromatics and trace metals are present in low quantities (i. e. <10 µg/L) and are only detected in groundwater immediately adjacent to the toe of the tailings impoundment. Cl and Na are found at concentrations of up 282 and 579 mg/L respectively. Dissolved oxygen is typically < 1 mg/L within the plume, while redox indicators Mn(II), Fe(II) and methane are detected between <0. 1 - 2. 6, 0. 2 - 3. 5 and <0. 1 - 2. 1 mg/L respectively within the plume. Solid phase geochemistry, determined through solid phase extractions, was coupled with aqueous geochemistry and reactive transport modeling to identify the dominant geochemical processes occurring within the plume. Based on scenarios evaluated using reactive transport modeling, the most likely origin for the presently observed, weakly reducing conditions in the plume appears to be the presence of a small amount of disssolved, degradable organic carbon. The dominant terminal electron acceptors appear to be Fe(III) and Mn(III/IV) in the plume core and dissolved oxygen at the plume fringe. Dissolved Fe and Mn are observed to enter the domain at the upgradient boundary at maximal concentrations of 4. 2 and 0. 7 mg/L respectively. Trace metal geochemistry of the aquifer material was also assessed using solid phase extractions. The potential for trace metal release via reductive dissolution of the native geologic material is considered minimal in this case, based on the weakly reducing nature of the plume and a lack of excessive trace metal content in the aquifer material.

Naphthenic acids (NAs) are an important group of organic pollutants mainly found in hydrocarbon deposits. Although these compounds are toxic, recalcitrant, and persistent in the environment, we are just learning the diversity of microbial communities involved in NAs- degradation and the mechanisms by which NAs are biodegraded. Studies have shown that naphthenic acids are susceptible to biodegradation, which decreases their concentration and reduces toxicity. Nevertheless, little is still known about their biodegradability. The present PhD Thesis’s work is aimed to study the biodegradation of simple model NAs using bacteria strains belonging to the Rhodococcus genus. In particular, Rh. sp. BCP1 and Rh. opacus R7 were able to utilize NAs such as cyclohexane carboxylic acid and cyclopentane carboxylic acid as the sole carbon and energy sources, even at concentrations up to 1000 mg/L. The presence of either substituents or longer carboxylic acid chains attached to the cyclohexane ring negatively affected the growth by pure bacterial cultures. Moreover, BCP1 and R7 cells incubated in the presence of CHCA or CPCA show a general increase of saturated and methyl-substituted fatty acids in their membrane, while the cis-mono-unsaturated ones decrease, as compared to glucose-grown cells. The observed lipid molecules modification during the growth in the presence of NAs is suggested as a possible mechanism to decrease the fluidity of the cell membrane to counteract NAs toxicity. In order to further evaluate this toxic effect on cell features, the morphological changes of BCP1 and R7 cells were also assessed through Transmission Electron Microscopy (TEM), revealing interesting ultrastructural changes. The induction of putative genes, and the construction of a random transposon mutagenesis library were also carried out to reveal the mechanisms by which these Rhodococcus strains can degrade toxic compounds such as NAs.

The identification of petroleum acids, also known as ‘naphthenic’ acids (NA), has been an analytical challenge for over 140 years. However, most recent interest in NA has arisen due to concerns over their presence and apparent associated toxic effect in oil platform produced waters and oil sands process waters (OSPW), respectively. Understanding the toxicity, transformations during biodegradation and remediation treatments and predicting the fate of NA in the environment will be aided by the identification of individual NA. However the elucidation of individual acid structures by standard chromatographic techniques, such as GC-MS, has so far been limited by the extreme complexity of the NA mixtures. Recent analysis of NA as the methyl ester derivatives, by multidimensional gas chromatography-mass spectrometry (GC×GC-MS), has resulted in the identification of several tri- to pentacyclic, aromatic and sulphur-containing acids as well as tricyclic diacids. Therefore the current investigation focused on the identification of the abundant bicyclic acids in petroleum and OSPW acid extracts, utilising the unparalleled chromatographic separation and mass spectrometric detection offered by GC×GC-MS. Analysis of fractionated NA as methyl esters, resulted in the first identification of several bicyclic acids in OSPW including several novel bridged bicyclic acids, several fused bicyclic acids, as well as some terpenoid-derived drimane and labdane acids. However, identifications were limited somewhat by a lack of reference mass spectra and lack of availability of reference compounds for co-chromatography. A complementary method, based on an historical approach, involving reduction of NA esters to hydrocarbons, was modified and substantially improved. Analysis of the hydrocarbons resulting from the reduced acids, by GC×GC-MS, and comparison of the hydrocarbon mass spectra with the more abundant reference spectra available for petroleum hydrocarbons, resulted in the identification of over 40 individual bicyclic acids including fused, bridged and terpenoid-derived acids. The study provides the most comprehensive analysis of one of the major classes of NA (the bicyclic acids) to date. The methods developed were applied to the structural elucidation of NA in commercial NA and OSPW NA and resulted in the identification of numerous alicyclic, aromatic and sulphur-containing acids, supporting and extending previous identifications. There is clear potential for this method to be used for the identification of other unknown acids and functionalised biomarkers in complex matrices. The new knowledge of the acid structures in petroleum and OSPW NA can now be used to inform future research into the environmental monitoring and toxicity of NA.

Naphthenic acids (NAs) and high molecular weight polycyclic aromatic hydrocarbons (HMW-PAHs) are both natural components of fossil fuels that cause a number of environmental issues. Using enrichment cultures derived from oil sands-process affected water (05PW), the biodegradation of three HMW-PAHs that differed in number of aromatic rings was investigated. All HMW-PAHs were degraded by up to 75% over 33 days. Bacterial communities were dominated by the genera Pseudomonasl Bacillus and Microbacterium and fungal communities by Cladosporium and Penicllium. Pseudomonas putida KT2440 has previously been shown to transform both NAs and other hydrocarbons and so was selected for co-culture biodegradation experiments with a NA-tolerant culture of Chlorella vulgaris Nr 211/12. Co-cultures demonstrated biodegradation of recalcitrant components of commercial NAs within 14 days and degraded significantly more adamantane-1-carboxylic acid (A1CA) than individual cultures of either P. putida or C. vulgaris within 33 days. Enrichment cultures derived from 05PW were used to further investigate the biodegradation of A1CA and 3EA. Both A1CA and 3EA were significantly degraded after 33 days and mass spectral analysis demonstrated the production of hydroxyadamantane intermediates with a concurrent decrease in toxicity. Comparisons of 165 rRNA gene sequences at days 0 and 33, during biodegradation showed an increase in abundance at day 33 of the genera Pseudomonas, Acidovorax, Flavobacterium and Methylobacterium.

Microfluidic H-cells and surface enhanced Raman spectroscopy are capable of analysing the asphaltene content of petroleum. An H-cell is a microfluidic device that exploits the non-turbulent flow of fluids within a micrometre-dimensioned channel. Diffusive separation in an H-cell permits a liquid that is miscible with the sample matrix to be used as an extractant. It was demonstrated that n-hexane can be used as extractant to obtain an asphaltene-free fraction of oil. The difference between the UV-Vis adsorption spectra of the asphaltene-free oil and the oil sample can then be used to estimate its asphaltene content. This has been demonstrated for a range of oils with asphaltene content between 1-30% and API gravity values between 40-10°, thus liquid petroleum and bitumen can be rapidly assayed by an H-cell; similarly, asphaltene and carboxylic acid content of oil can be determined simultaneously when methanol is used as extractant. The results were shown to be comparable to assays achieved via the ASTM D4124 and ASTM D974 methods respectively. For the first time it was demonstrated that surface enhanced Raman spectroscopy, using a gold substrate and illumination at 514 nm, can detect extremely low concentrations of asphaltene. This was shown to be achievable for asphaltene and related materials at concentrations of 0.001 ppm. In addition, data also demonstrated that the core of the Raman-responsive units within asphaltene have crystallite sizes equivalent to the Raman-responsive units in kerogen (~3 nm). Both methods provide technological advances because they make it possible to detect asphaltene in small sample volumes, using smaller footprint instrumentation. The H-cell method would be extremely useful for appraising oilfield potential, record the attenuation of oil-spills and provide frequent geochemical data that can monitor these at point of need. Similarly, the SERS technique widens the field of application into areas previously inaccessible to current techniques such as the effect of low concentrations of asphaltene-like materials in ecological and living systems.

Com o aumento do processamento de petróleos mais pesados, torna-se interessante realizar um estudo dos possíveis mecanismos de deterioração que poderão ocorrer em função do aumento do Índice de Acidez Total (IAT). Dessa forma, o presente trabalho teve como objetivo principal avaliar as linhas e equipamentos que compõe a bateria de pré-aquecimento da carga de uma unidade de Hidrotratamento (HDT) de diesel. Esse trecho teoricamente está susceptível a ocorrência de corrosão por ácidos naftênicos devido a dois principais fatores: a presença desses ácidos com teores de neutralização superiores a 0,5 mg KOH/g na composição química da carga e a temperatura de processamento, que se encontra em um intervalo de 200 a 400ºC, adequado para existência de tal mecanismo de deterioração. Os dados obtidos em campo referentes à taxa de corrosão das linhas e dos equipamentos foram parametrizados em suas variáveis operacionais e através de uma análise comparativa com dados encontrados na literatura foram obtidas informações importantes para avaliar a ocorrência de corrosão naftênica.
With the increased processing of heavier oils, it is interesting a study of possible mechanisms of deterioration that may occur due to the increase of the Total Acid Number (TAN). Thus, this study aims to evaluate the main lines and equipment that comprise the battery of preheating of the load of a unit of Hydrotreating (HDT) of diesel. This excerpt is theoretically likely to occur from corrosion by naphthenic acids due to two main factors: the presence of these acids with levels of neutralizing more than 0.5 mg KOH/g in the chemical composition of the load and the temperature of processing, which is in a range from 200 º C to 400 º C, suitable for the existence of such a deterioration mechanism. Data from field concerning to the rate of corrosion of the lines and equipment were parameterized in their operational variables and through a comparative analysis with data found in literature were obtained important information to evaluate the occurrence of naphthenic corrosion.

Adequate wastewater management is a crucial element to achieve water sustainability in the petroleum refining sector, as their operations produce vast quantities of wastewater with potentially harmful contaminants. Treatment technologies are therefore pivotal for stopping these chemicals from entering the environment and protecting receiving environments. However, refining effluents are still linked to serious pollution problems, partly because little progress has been made in determining the causative agents of the observed biological effects, resulting in non-targeted treatment. Here it is shown that naphthenic acids, which have been reported as toxic and recalcitrant, are important components of refining wastewater resulting from the processing of heavy crude oil and that they have a significant contribution to the toxic effects exerted by these effluents. Furthermore, it was found that their chemical stability makes them highly resistant to remediation using Pseudomonas putida and H2O2/Fe-TAML (TetraAmido Macrocyclic Ligands) systems under laboratory conditions, and only sequential aliquots of Fe-TAML catalysts and H2O2 showed to partially degrade naphthenic acids (50 mg/L) within 72 hours. Results suggest that a combinatorial approach of Fe-TAML/H2O2 followed by biodegradation might improve current treatment options, but further optimisation is required for the biological treatment. These results can serve as a starting point for better environmental regulations relevant to oil refining wastewater resulting from heavy crude oil, as naphthenic acids are not currently considered in the effluent guidelines for the refining sector. Furthermore, the degradation of naphthenic acids under mild conditions using Fe-TAML/H2O2 systems indicates that these catalysts hold promise for the remediation of refining wastewater in real-life scenarios.

Grupno-strukturna analiza naftnih kiselina izolovanih iz srednjih uljnih komercijalnih frakcija vojvođanske nafte „Velebit” rađena je analizom IR-, ¹H- i ¹³C NMR- i ESI-MS spektara niske rezolucije. Određeno je šest klasa karboksilnih kiselina opšte molekulske formule C_nH_2n-ZO₂. To su karboksilne kiseline u opsegu masa 240-466 sa 15-31 C atoma u molekulu koje su grupisane u pet cikloalkil Z-serija: monociklična- (C_nH_2n-2O₂, 14.72%), biciklična- (C_nH_2n-4O₂, 34.63%), triciklična- (C_nH_2n-6O₂, 25.03%), tetraciklična- (C_nH_2n-8O₂, 10.04%), pentaciklična klasa karboksilnih kiselina (C_nH_2n-10O₂, 4.99%) i jedna alkanska klasa kiselina sa alkil grupama otvorenog niza (C_nH_2nO₂, 10.57%).Razdvajanjem na bazi različite kiselosti i njihove rastvorljivosti u vodi na određenim pH vrednostima u rasponu od pH 2-10 dobijeno je devet užih frakcija kiselina. Ekstrakcijom sa etrom u vodi nerastvornih kiselina u rasponu od po jedne pH jedinice dobijena je sledeća distribucija masa: 9.57% (pH 10), 12.69% (pH 9), 5.91% (pH 8), 4.85% (pH 7), 2.44% (pH 6), 11.71% (pH 5), 23.94% (pH 4), 16.76% (pH 3) i 10.12% (pH 2). Razdvajanjem kiselina na bazi njihove kiselosti oko 50% mase kiselina ekstrahovano je od pH 2-4, znači u grupi jačih kiselina. Masenom spektrometrijom niske rezolucije ESI-MS na pH 4 vidi se da su u smeši kiselina skoncentrisane kiseline sa više prstenova u alkilnom delu sa maksimumom na tricikličnim kiselinama (36.50%), dok su pojedinačno najzastupljenije tetraciklične strukture kiselina C₂₀H₃₂O₂(4.43%) i C₂₁H₃₄O₂(4.56%). Na pH 8 biciklične- i triciklične strukture su zastupljene ukupno sa 65.02% sa maksimalno zastupljenim kiselinama sa 20-26 C atoma u molekulu, a izdvajaju se C₂₂H₃₈O₂ (5.26%) biciklične- i C₂₄H₄₂O₂(7.01%) triciklične strukure, a od tetracikličnih struktura kiselina izdvaja se C₂₄H₄₀O₂ (4.77%). Na pH 10 najzastupljenije izolovane kiseline su aciklične, odnosno masne kiseline zastupljene sa 25.28%, a najdominantnije su strukture C₂₁H₄₂O₂ (4.83%), dok su ostale klase kiselina ujednačene po svom masenom udelu u odnosu na sastav u ukupnoj polaznoj smeši kiselina. Drugi deo rada obuvata derivatizaciju izolovanih prirodnih naftnih kiselina. Sintetizovani su funkcionalni kiseonični metil-, etil-, n-butil-,  terc-butil- i benzil-derivati naftnih kiselina kao i funkcionalni azotni derivati: amidi i anilidi naftnih kiselina. Sinteze navedenih estara rađene su klasičnim postupcima i modifikovanom metodom esterifikacije u kiselo-katalizovanim uslovima upotrebom mikrotalasa kao ko-katalizatora, što je imalo za cilj skraćenje reakciong vremena i poboljšanje ekoloških sintetskih uslova.Modifikacijom sinteze metilnaftenata MT-zagrevanjem 48 puta je skraćeno vreme trajanja sinteze, prinosi ni promenom reakcionih parametara (vreme, snaga MT) nisu bitno promenjeni. Strukturnom analizom ESI-MS spektra polaznih kiselina i metilnaftenata dobijenih metilovanjem naftnih kiselina utvrđeno je da je odnos klasa u dobroj podudarnosti. Prinos estara u ovoj sintezi je 95.47%. Esterifikacija naftnih kiselina etil alkoholom rađena je u uslovima kisele katalize uz konvencionalno zagrevanje (91.76%), a modifikacijom metode MT-zagrevanjem (150 W) reakciono vreme je skaćeno 96 puta (92.19%). Esterifikacija naftnih kiselina n-butil alkoholom rađena je uz sumpornu kiselinu kao katalizator i uz konvencionalno zagrevanje (94.24%), a u uslovima MT-zagrevanja (150 W) 72 puta je skraćeno reakciono vreme (61.15%). Sinteza terc-butilnaftenata rađena je prevođenjem naftnih kiselina u hloride a zatim reakcijom sa terc-butil alkoholom nastaju terc-butilnaftenati (80.17%). Modifikovanom metodom klasične reakcije esterifikacije naftnih kiselina terc-butil alkoholom katalizovanom sumpornom kiselinom u uslovima MT-zagrevanja (150 W) ostvaren je prinos od 85.49% a vreme trajanja reakcije je 5 minuta. Sinteza benzilnaftenata rađena je prevođenjem naftnih kiselina u hloride a zatim reakcijom sa benzil alkoholom nastaju benzilnaftenati (84.43%), a modifikovanom metodom klasične kiselo-katalizovane esterifikacije naftnih kiselina benzil alkoholom u uslovima MT-zagrevanja (150 W) ostvaren je prinos od 85.49% uz reakciono vreme od 5 minuta. Sinteza amida naftnih kiselina rađena je iz hlorida reakcijom sa amonijakom. Prinos čistih amida je 65.74%, a reakcija amidacije sa amonijakom trajala je 15 minuta. Strukturnom analizom ESI-MS spektra amida naftnih kiselina utvrđen je grupno-strukturni sastav amida. Među strukturama amida naftenskih kiselina takođe su dominantne biciklične- i triciklične strukture, kao i u smeši slobodnih kiselina. Sinteza anilida naftnih kiselina rađena je iz hlorida reakcijom sa anilinom. Prinos čistih anilida je 96.48%, a reakcija amidacije anilinom trajala je 30 minuta. Strukturnom analizom ESI-MS spektra anilida naftnih kiselina utvrđen je grupno-strukturni sastav proizvoda, anilida. Među strukturama anilida naftenskih kiselina takođe su dominantne biciklične- i triciklične strukture kao i u smeši slobodnih kiselina.U trećem delu ovog rada ispitivana je biološka aktivnost naftnih kiselina auksinskog i giberelinskog tipa, njihov uticaj na ožiljavanje reznica, ukorenjivanje bočnih grana i mikroizdanaka biljaka, na aktivnost biljnih hormona, kao i na usvajanje metalnih jona kod biljaka. Aktivnost naftenskih kiselina utvrđena je pomoću tri in vitro  biološka testa. „Koleoptil test”, rađen je na dva supstrata, odnosno na semenu ozime pšenice novosadske sorte Partizankai jare pšenice takođe novosadske sorte Venera. Referentna aktivnost u testu rađena je sa -naftilsirćetnom 3-indolsirćetnom kiselinom. U oba testa ustanovljen je približno isti odnos aktivnosti rastvora naftenskih kiselina i aktivnosti standardnih biljnih hormona. „Test inhibicije klijanja” semena rađen je sa semenom crne slačice, Brasscia nigra. Najveći uticaj naftenskih kiselina na inhibiciju klijanja postignut je u rasponu koncentracija kiselina od 10^-7 -10^-8 mol/L (0.05-0.01 mg/L). Testovi za šest užih frakcija dobijenih iz smeše ukupnih kiselina razdvajanjem na bazi različite rastvorljivosti pri različitim pH vrednostima pokazuju istu aktivnost kao 3-indolsirćetna kiselina (0.5 mg/L), a da je frakcija izdvojena iz vodenog rastvora na pH 7 takođe aktivna ali u poređenju sa 3-indolsirćetnom kiselinom to je 10 puta niža aktivnost. Hormonska aktivnost giberelenskog tipa ispitivanih kalijumovih soli naftenskih kiselina utvrđena je „Endosperm testom”, u kojem je određivana aktivnost amilaze spektrofotometrijskim praćenjem povećanja koncentracije redukujućih šećera u endospermu semena tretiranog ječma i poređena sa aktivnošću rastvora giberelinske kiseline (GA3). Rezultati ovih testova pokazuju da delovanjem vodenih rastvora užih frakcija naftenskih kiselina u koncentraciji 1.0 mg/L (3.5 x 10^-6 mol/L)frakcija izolovana pri pH 8 ima aktivnost koja je približno u opsegu aktivnosti giberelina koncentracije 10^-2-10^-3 mg/L. Natrijum-naftenati u koncentraciji od 10^-6 do 10^-8 mol/L stimulišu formiranje adventivnih korenova kod reznica suncokreta pa je broj korenova po biljci 40 puta veći kod biljaka koje su bile potopljene u rastvor natrijum-naftenata u odnosu na one koje su bile potopljene u vodu, a sličan efekat utvrđen je i pri tretiranju bočnih grana suncokreta. Ožiljavanje drvenastih biljaka rađeno je na reznicama bele topole (Populus alba) i reznicama američke crne topole (Populus deltoides). Uočen je jasan inhibitomi efekat na rast korenčića i izbojka u vodenom medijumu sa 10^-4 mol/L naftenskih kiselina, dok je tretman od 24 časa doprineo većem broju korenčića na donjih 5 cm reznice, kao i ukupnog broja korenčića nego kod kontrole. U testu ukorenjivanja mikroizdanaka kod hrizantema najveći broj korenova dobijen je nakon tretmana sa rastvorom koji sadrži 10 µmol/L ukupnih naftenata i tretmanom sa 50 µmol/Lfrakcijom kiselina izolovanom pri pH 7. Oba rezultata su na nivou aktivnosti 3-indolbuterne kiseline koncentracije 10 µmol/Lšto znači da u ovom slučaju frakcionacija nije neophodna. Efekti natrijum-naftenata na ukorenjivanje praćeni su merenjem nivoa totalnih peroksidaza i amilaze,  kao i sadržaja redukujućih šećera i ukupnih proteina u bazalnim delovima reznica bagrema(Rozaszin-AC).  Nakon 1; 3 i 6 dana reznice su uzete za biohemijske analize. U svakom slučaju, aktivnosti IAA-oksidaze i amilaze su se povećavale do trećeg dana,  a zatim smanjuje. Efekat je bio jače izražen posle tročasovnog tretmana sa natrijum-naftenatima u poređenju sa šestočasovnim tretmanom i kontrolom. Sadržaj rastvornih proteina je bio povećan jedan dan posle tretmana, smanjen trećeg i ponovo povećan šestog dana, osim za šestočasovni tretman natrijum-naftenatima, kada je efekat bio sasvim suprotan.Test uticaja naftnih kiselina na nivo kadmijuma u biljkama pokazuje fiziološko delovanje naftnih kiselina na snižavanje nivoa teških metala u biljci, u ovom slučaju kadmijuma. Ispitivan je efekat niske koncentracije natrijum-naftenata (10^-7 mol/L) na ukupan sadržaj Cd u pojedinim frakcijama interćelijskog prostora kao i unutar ćelija, kao i na neke fiziološke i biohemijske parametre kod mladih biljaka soje koje su uzgajane u prisustvu kadmijum-hlorida koncentracije 1 mmol/L. Prisustvo naftenata smanjuje sadržaj ukupnog kadmijuma kako u korenu tako i u stablu i listovima u proseku za oko 40% i ublažava štetne efekte kadmijuma na aktivnost nitrat-reduktaze kao i na sadržaje fotosintetskih pigmenata.Tretman biljaka niskim koncentracijama natrijum-naftenata utiče na akumulaciju nekih esencijalnih elemenata kod mladih biljaka soje. Prisustvo naftenata (10^-7  mol/L) značajno povećava sadržaj Mn, Fe, Zn i Ni u korenu, ali u stabljici i listovima samo sadržaj Fe i Mn. U korenu, sadržaj Mn je četiri puta veći a sadržaji Fe, Zn i Ni su povećani 17%, 60% i 68%, respektivno. Ispitivanja na celeru i mrkvi su potvrdila da uticaj naftenata na mineralnu ishranu zavisi od primenjenog elementa i da je način preuzimanja određenih jona različit, što ima za posledicu ili povećanje ili smanjenje sadržaja pojedinih jona u nekim delovima biljaka. Mlade biljke celera i mrkve, gajene u hranljivom medijumu, tretirane su natrijumovim solima naftenskih kiselina (10^-7 mol/L) folijarno ili prisustvom u hranljivom medijumu. Jedino je tretman putem prisustva naftenata u hranljivom medijumu smanjio svežu masu korena i nadzemnog dela oko 20% kod obe biljke.Oba tretmana uticala su na sadržaj Fe, Cu, Mn, Mg i Ca kod biljaka celera i Fe, Mn, Zn i Na kod biljaka mrkve. Kod biljaka celera došlo je do smanjenja sadržaja navedenih nutrienata dok je u korenu biljaka mrkve došlo do povećanja sadržaja Fe za 45%, Mn za 70% i Zn za 37%. Kod ovih biljaka prisustvo naftenata u hranljivom medijumu dovelo do smanjenja mase korenova i nadzemnih delova, što je potpuno suprotno od rezultata dobijenih kod biljaka soje.  Folijarnim tretmanom je značajnopovećana masa nadzemnog samo kod celera.
Group-structural analysis of naphthenic acids isolated from middle commercial fractions of Vojvodina oil „Velebit” was performed with the analysis of IR-,¹H- and ¹³C NMR- and ESI-MS low resolution spectrums. Six classes of carboxylic acids of the general molecular formula C_nH_2n-ZO₂ were determined. These are carboxylic acids with mass range of 240-466 with 15-31 C atoms in molecule which are grouped in five cycloalkyl Z-series: monocyclic- (C_nH_2n-2O₂, 14.72%), bicyclic- (C_nH_2n-4O₂, 34.63%), tricyclic- (C_nH_2n-6O₂, 25.03%), tetracyclic- (C_nH_2n-8O₂,  10.04%), pentacyclic class of carboxylic acids (C_nH_2n-10O₂, 4.99%) and one alyphatic class of acids with open chain alkyl groups (C_nH_2nO₂, 10.57%).By fractioning on the basis of different levels of acidity and their solubility in water with pH values ranging from pH 2-10 nine subfractions of acids were obtained. By extraction with ether in water undissolved acids in the range of one pH unit the following distribution of mass was performed: 9.57% (pH 10), 12.69% (pH 9), 5.91% (pH 8), 4.85% (pH 7), 2.44% (pH 6), 11.71% (pH 5), 23.94% (pH 4), 16.76% (pH 3) and 10.12% (pH 2). By fractioning acids on the basis of their acidity about 50% of acid  mass was extracted at pH 2-4, i.e., in the group of stronger acids. Low resolution mass spectrometry ESI-MS shows that at pH 4 acids with more rings in the alkyl section were concentrated in the mixture with maximum at tricyclic acids (36.50%), while individually tetracyclic acid structures C₂₀H₃₂O₂ (4.43%) and C₂₁H₃₄O₂ (4.56%) were most prominent. At pH 8 bicyclic- and tricyclic structures are represented  together by 65.02% with acids with 20-26 C atoms in molecule being represented the most, and C₂₂H₃₈O₂  (5.26%) bicyclic- and C₂₄H₄₂O₂(7.01%) tricyclic structures stand  out, while with tertacyclic acid structures C₂₄H₄₀O₂ (4.77%) stands out. At pH 10 most represented isolated acids are acyclic, i.e., fatty acids which are represented by 25.28%, with the most dominant C₂₁H₄₂O₂ structures (4.83%), while the other classes  of acids are well balanced in their mass share in relation to the composition of the overall initial acid mixture.The second part of this work deals with derivatization of the isolated natural naphthenic acids. Functional oxygen methyl-, ethyl-, n-butyl-, tert-butyl and benzyl-derivatives of naphthenic acids as well as functional nitrogen derivatives: amides and anilides of naphthenic acids were synthesized. The syntheses of the above mentioned esters were performed by conventional methods and by a modified method of esterification in acid-catalyzed conditions using microwaves as a co-catalyst with the aim of shortening the reaction time and improving the ecological synthetic conditions. By modification of methyl naphthenates synthesis using MT-heating the time period for synthesis is reduced 48 times and the yield does not significantly change even after the reaction parameters (time, MT power) have been altered. Using structural analysis of ESI-MS spectrum of initial carboxylic acids and the methyl naphthenates obtained through methylation of naphthenic acids it was establishedthat the class ratio shows great compatibility. The esters yield in this synthesis is 95.47%. The esterification of naphthenic acids with ethyl alcohol done under the conditions of acid catalysis with conventional heating (91.76%), and with the modified method MT-heating (150 W) the reaction time is reduced 96 times (92.19%). The esterification of naphthenic acids with n-butyl alcohol was performed using sulphuric acid as a catalyst with conventional heating (94.24%), and under MT-heating conditions (150 W) reaction time was 72 times  shorter (61.15%). The synthesis of  tert-butyl naphthenates was performed by conversion of naphthenic acids into chlorides, followed by the reaction with tert-butyl alcohol which resulted in tert-butyl naphthenates (80.17%). By the modified method of conventional reaction of esterification of naphthenic acids using tert-butyl alcohol catalysed with sulphuric acid in MT-heating conditions (150 W) the yield was 85.49% and reaction time was 5 minutes. The synthesis of benzyl naphthenates was performed by conversion of naphthenic acids into chlorides, followed by a reaction with benzyl alcohol which produces benzyl naphthenates (84.43%), whereas the modified method of conventional acid-catalysed esterification of naphthenic acids using benzyl alcohol under MT-heating (150 W) conditions the yield was 85.49% with the reaction time of 5 minutes. The synthesis of naphthenic acid amides was done from chlorides by reaction with ammonia. The yield of pure amides was 65.74%, and the reaction of amidation with ammonia lasted for 15 minutes. The structural analysis of ESI-MS spectrum of naphthenic acid amides determined the group-structural composition of amides. With the structures of amides of naphthenic acids bicyclic- and tricyclic structures are also dominant, as in the mixture of free acids. The synthesis of naphthenic acid anilides were performed from chloride by reacting with aniline. The yield of pure anilides was 96.48%, and the reaction of amidatation lasted for 30 minutes. The structural analysis of ESI-MS spectrum of naphthenic acid anilides determined the group-structural composition of anilide products. With the structures of anilides of naphthenic  acids bicyclic- and tricyclic structures are also dominant, as in the mixture of free acids.The third part of this work tests the biological activity of naphthenic acids of auxine and gibberellinic type, their influence on the rooting of cuttings, lateral branches and microshoots of plants, on the activity of plant hormones as well as on the metal ions uptake by plants. The activity of naphthenic acids was determined using three in vitro biological tests. „Koleoptil test”, was done on two substrates, namely the seed of winter wheat of the Partizankasort and the spring wheat of the Venerasort. The referential activity in the test was performed with α-naphthylacetic- and 3-indolacetic acid. Both tests showed approximately the same ratio of activity of naphthenic acid solutions and standard plant hormones. „Germination Inhibition Test” of the seed was performed using Brasscia nigraseed. The greatest influence of naphthenic acids to germination inhibition was achieved in the acid concentration ranging from 10^-7-10^-8 mol/L (0.05-0.01 mg/L). The tests for six narrow fractions obtained from the overall mixture of acids through fractioning on the basis of different solubility at different pH values show the same activity as 3-indolacetic acid (0.5 mg/L), with the fraction isolated from the aqueous solution at pH 7 also active but in comparison to 3-indolacetic acid this activity was 10 times lower. Hormone activity of gibberellinic type of the potassium salts of naphthenic acids was determined using “Endosperm Test” where amylase activity was determined by spectrophotometric measuring of the increase of the concentration of reducing sugars in endosperm in the treated barley seed which was then compared to the activity of the gibberellic acid solution (GA3).  The results of these tests indicate that the activity of aqueous solutions of narrow fractions of naphthenic acids in the concentration of 1.0 mg/L (3.5 x 10^-6 mol/L)the fraction isolated  at pH 8 has the activity which is approximately within the range of activities of gibberellin of the concentration of 10^-2-10^-3 mg/L. Sodium salts of naphthenic acids in concentrations of 10^-6 do 10^-8 mol/L stimulated formation of adventitious roots in sunflower cuttings even by a factor of 40 compared with control, the effect being also observed lateral branches of interspecies sunflower hybrids. The obtained results suggest the possibility of using naphthenic acids as a means for rooting of plant cuttings.Rooting of hardwood plants was investigated on the cuttings of white poplar (Populus alba) and black poplar (Populus deltoides). The distinct inhibitory effect on the root and shoot growth in water culture was detected in the concentration of naphtenic acids 10^-4 mol/L, but 24-hour treatment raised the number roots on undermost 5 cm of the cutting, as well as the total number of roots, comparing to the control.In the test of rooting microshoots ofchrysanthemum the highest number of roots was achieved after the treatment with solution containing 10 µmol/L of total napthenates, as  well as after the treatment with fraction of naphthenic acids which was isolated at pH  7 in concentration of 50 µmol/L. Both results are on the level of activity of 3-ndolbutyric acid in concentration of 10 µmol/L which suggests that in this case ractionation is not necessary.The effects of sodium naphthenates on rooting were investigated by measuring the level of total peroxidases and amylase, along with the contents of reducing sugars and total proteins in basal parts of cuttings of black locust (Rozaszin-AC). After 1; 3 and 6 days cuttings were taken for biochemical analysis. In all cases, the activities of IAA-oxidase and amylase increased to the third day and showed a decrease afterwards. The effect was more pronounced after the three-hour treatment with sodium naphthenates, compared to the six-hour treatment and control. The content of soluble proteins increased one dayafter the treatment and decreased to the third and again increased to the sixth day, an exception being the six-hour treatment with sodium naphthenate, when the effect was completely opposite.The test of naphthenic acids influence on the level of cadmium in plants showed physiological activity of naphthenic acids on the decrease of the level of heavy metals,  in this case cadmium, in the plant. The effect of low concentrations (10^-7 mol/L) of sodium naphthenate on total content of Cd in the intercellular space and inside cells, as  well as on some physiological and biochemical parameters of young soybean plants grown in the presence of 1 mmol/L solution of cadmium chloride was investigated. Presence of naphthenate reduced in average by 40 % content of total and intracellular Cd in root, stem and leaves and alleviated the harmful effect of Cd on activity of nitrate reductase and content of photosynthetic pigments.Treatment of soybean plants with low concentrations of sodium naphthenate influenced the accumulation ofsome essential elements by the young plants. The presence of naphthenates (10^-7 mol/L) significantly increased content of Mn, Fe, Zn and Ni in root, but in stem and leaves increased only contents of Fe and Mn. Inroot, the content of Mn increased four times while contents of Fe, Zn and Ni increased by 17%,  60% and 68% respectively compared to the control.Investigations on celery and carrot  confirmed that the influence of naphthenates on mineral nutrition depends on the applied element and that the way of uptake of certain ions is different, which results in either increase or decrease of the contents of some ions in certain parts of plants. Young plants of celery and carrot, were grown in the nutrient medium and treated with sodium salts of naphthenic acids (10^-7 mol/L) over the leaves or with its presence in the nutrient medium. Only the treatment based on the  presence of naphthenates in the nutrient medium resulted in the decrease of the fresh mass of root and aboveground part by about 20% for both plants. Both treatments had influence on the content of Fe, Cu, Mn, Mg and Ca in the plants of celery and Fe, Mn, Zn and Na in the plants of carrots. In the plants of celery the content of the mentioned nutrients was decreased, while in the root of plants of carrot  the content was increased, Fe by 45%, Mn by 70% and Zn by 37%. With these plants  the presence of naphthenates in the nutrient medium caused the reducing roots and aboveground parts, which is completely opposite from the results obtained with soybean plants. The treatment by leaves significantly increased the mass of aboveground part only with celery.

Predviđena istraživanja u ovoj doktorskoj disertaciji su usmerena u pravcu modifikacije klasičnih metoda i postupaka za transformaciju karboksilne grupe prirodnih i sintetičkih karboksilnih kiselina. Modifikacije su rađene novim, savremenim, ekonomski i ekološki opravdanim metodama rada u mikrotalasnom reaktoru. Modifikovanim sintetskim postupcima u mikrotalasnom reaktoru urađena je sinteza amida, hidroksamskih  derivata, kao i redukcija individualnih naftnih kiselina i  smeše  prirodnih naftnih kiselina „Velebit“ do alkohola. Prirodne naftne kiseline korišćene u ovom radu su prvo izolovane iz gasne frakcije (interval destilacije 168-290 °C) vojvođanske nafte „Velebit“ a potom prečišćene i razdvojene na uže frakcije na osnovu različite kiselosti. Nakon toga, izvršena je njihova karakterizacija GC-MS-EI analizom (čime je potvrđeno da dolazi do strukturne diferencijacije kiselina). U radu je takođe ispitana biološka aktivnost sintetizovanih derivata. Proučavan je uticaj prirodnih naftnih kiselina „Velebit“ i njenih derivata na rast  pet sojeva Pseudomonas sp., kao i uticaj odabranih sintetisanih jedinjenja na proliferaciju četiri ćelijske linije humanih tumora pri čemu je kao kontrola služila jedna zdrava humana ćelijska linija.
The investigation of this doctoral dissertation is directed toward the modification of the  transformation of the carboxylic group of natural and synthetic carboxylic acids. The dissertation takes into consideration the classical methods and procedures of the reaction and modifies them using microwave reactor. The synthesis of amides, hydroxamic derivatives, as well as the reduction  of individual petroleum acids and acid mixtures of natural oil "Velebit" to alcohol were achieved  by the modifications made to the synthetic methods in the microwave reactor. The natural oil acids used within this study were first isolated from the gas fraction (distillation interval 168-290 °C) of the Vojvodina's crude oil "Velebit", and then purified and separated by the narrow fractions under the different acidity. After that, their characterisation was made by the GC-MS-EI analysis which confirmed that the structural differentiation of   acids had been achieved. Also, the biological activity of the synthesized derivatives are analysed. The impact of natural petroleum acids "Velebit" and its derivatives on the growth of five strains of  Pseudomonas  sp. was studied, as well as the impact of selected synthesized compounds on the proliferation of four human tumor cell lines wherein one healthy human cell lines used as the control.

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PRH-28 ANP
A presença de ácidos naftênicos no querosene de aviação (QAV) implica em um aumento de sua acidez com efeito corrosivo elevado, diminuição da estabilidade térmica, formação de sais insolúveis e depósitos de carbono. A remoção desses compostos por adsorção é considerada uma alternativa eficiente, uma vez que podem ser recuperados, purificados e comercializados para outros fins. A síntese e caracterização de peneiras moleculares mesoporosas do tipo MCM-41 com potencial aplicação em adsorção e catálise vêm sendo bastante estudada em função de suas características, como elevada área superficial, diâmetro e volume de poros. Neste contexto, este trabalho propôs a síntese de adsorventes do tipo MCM-41 modificados, visando à remoção de ácidos naftênicos em mistura modelo de QAV (ácido n-dodecanóico em n-dodecano). Os adsorventes MCM-41, Sr-MCM-41, La- MCM-41, Ce-MCM-41, Sr-La-MCM-41, Sr-Ce-MCM-41 foram sintetizados pelo método hidrotérmico e caracterizados pelas técnicas de análise termogravimétrica (TG), difração de raios-X (DRX), adsorção/dessorção de N2 através dos métodos Brunauer, Emmett e Teller (BET) e Barrett, Joyner e Halenda (BJH), espectroscopia na região do infravermelho por transformada de Fourier (FT-IR), microscopia eletrônica de varredura com espectroscopia de energia dispersiva por raios-X (MEV/EDS) e pH do ponto de carga zero (pHpzc). Foi realizado um estudo para seleção do adsorvente a ser utilizado nos estudos de adsorção. Com o adsorvente selecionado, foram realizados estudos cinéticos e equilíbrio de adsorção em sistema de banho finito. A partir dos dados obtidos, foi avaliado o sistema continuo de leito fixo e os ciclos de adsorção/dessorção. O método hidrotérmico foi eficiente, conforme os resultados obtidos pelas análises de caracterização, uma vez que após a incorporação dos metais, os materiais mantiveram a estrutura padrão da MCM-41. A partir do estudo do pHpzc verificou-se que a incorporação do metal alcalino terroso Sr aumentou a basicidade de todos os materiais. O adsorvente Sr-Ce-MCM-41 apresentou maior estabilidade térmica, bem como maiores volume e diâmetro de poros, apresentando também uma maior capacidade adsortiva. O estudo cinético permitiu verificar que o equilíbrio foi atingido após 420 minutos, com capacidade de 0,64 gác.g-1 ads e % de remoção de 82,5%. A isoterma de adsorção apresentou comportamento do tipo IV e a maior capacidade adsortiva quantificada na faixa de concentração estudada foi de 0,8 gác.g-1 ads. O modelo cinético de Langmuir- Freundlich e o modelo de Brunauer, Emmett e Teller (BET) representaram de forma satisfatória os dados experimentais da cinética e equilíbrio de adsorção em sistema de banho finito. No sistema de leito fixo, os tempos de ruptura e saturação da curva foram afetados pela variação da vazão e da concentração de alimentação do leito. Os dados experimentais foram ajustados ao modelo de Langmuir-Freundlich, uma vez que foram desprezados os efeitos de resistência à transferência de massa e de difusão. Os estudos de adsorção/dessorção indicaram a possibilidade de recuperação de ácidos naftênicos visando seu posterior aproveitamento e aplicação. O adsorvente estudado Sr-Ce-MCM-41 apresentou potencial para a remoção de ácidos naftênicos presentes em QAV modelo nas condições estudadas.
The presence of naphthenic acids in the aviation kerosene (jet fuel) implies an increase in its acidity with high corrosive effect, decreased thermal stability, formation of insoluble salts and carbon deposits. The removal of these compounds by adsorption is considered to be an effective alternative, since they can be recovered, purified and sold for other purposes. The synthesis and characterization of mesoporous molecular sieves MCM-41 type with potential application in adsorption and catalysis have been extensively studied due to their characteristics, such as high surface area, diameter and pore volume. In this context, this paper proposed the adsorbent synthesis of MCM-41 modified type, aimed at removing naphthenic acid mixed model of jet fuel (n-dodecanoic acid in n-dodecane). The MCM-41, Sr-MCM- 41, La-MCM-41, Ce-MCM-41, Sr-La-MCM-41, Sr-Ce-MCM-41 adsorbents were synthesized by hydrothermal method and characterized by techniques thermogravimetric analysis (TGA), X-ray diffraction (XRD), N2 adsorption/desorption using the Brunauer, Emmett and Teller (BET) and Barrett, Joyner and Halenda (BJH) methods, spectroscopy in the infrared Fourier transform (FT-IR), scanning electron microscopy with energy dispersive spectroscopy X-ray (SEM/EDS) and pH of zero charge point (pHpzc). A study was conducted to check the adsorbent for use in adsorption studies. With the selected adsorbent, kinetic studies were performed and adsorption equilibrium finite bath system. From the data obtained, we evaluated the system continuous fixed bed and the cycles of adsorption/desorption. The hydrothermal method was effective as the results of the characterization analyzes, since after the incorporation of metals, materials maintained the pattern structure of MCM-41. From the PHpzc study it was found that the incorporation of the alkaline earth metal Sr increased basicity of all materials. The Sr-Ce-MCM-41 adsorbent has higher thermal stability and higher pore volume and pore diameter, also having a greater adsorption capacity. The kinetic study showed that equilibrium is reached after 420 minutes, with a capacity of 0.64 gac.g-1 ads and % removal of 82.5%. The adsorption isotherm presented type IV behavior and higher adsorptive capacity quantified in the studied concentration range was 0.8 gac.g-1 ads. The kinetic model of Langmuir-Freundlich and model of Brunauer, Emmett and Teller (BET) were satisfactory experimental data of adsorption kinetics and equilibrium in finite bath system. In the fixed bed system, the breakthrough time and saturation curve were affected by varying the flow rate and the bed of the feed concentration. The experimental data were fitted to the model of Langmuir-Freundlich, since the effects of mass transfer resistance and diffusion were discarded. Studies of adsorption/desorption indicated the possibility of naphthenic acid recovery aiming their subsequent use and application. The adsorbent studied Sr-Ce-MCM-41 has potential for the removal of naphthenic acids present in jet fuel model in the conditions studied.

Ácidos naftênicos correspondem à complexa mistura de ácidos carboxílicos presentes no petróleo, responsáveis diretamente pela sua acidez e pela sua corrosividade em fase líquida durante o refino. Tais compostos também estão presentes nas frações destiladas do petróleo, causando diversos problemas na qualidade final do produto. Uma possível forma de remover esses ácidos das frações destiladas é através da adsorção em materiais porosos. Contudo, os resultados até então apresentados indicam que resinas trocadoras de íons seriam os melhores adsorventes destes compostos, o que poderia aumentar o custo do processo e diminuir sua viabilidade. Neste trabalho, dois adsorventes comerciais (argila e alumina ativada) foram caracterizados por diversas técnicas físico-químicas e avaliados quanto à sua capacidade de remover os ácidos naftênicos de frações médias e pesadas de petróleo. Avaliou-se, ainda, para fins de comparação, o comportamento de ácidos naftênicos comerciais em óleos sintéticos preparados com óleo mineral. Em complementação, a corrosividade do aço carbono nos meios estudados foi também verificada. A argila apresentou maior afinidade com os ácidos naftênicos, tendo capacidade de adsorção superior e cinética de processo ligeiramente mais rápida às da alumina para as cargas sintéticas. No entanto, em virtude da maior concorrência pelos sítios de adsorção, apresentada pelos outros componentes presentes em óleos reais, observou-se uma perda na eficiência para estas amostras. Neste caso, a alumina apresentou melhores resultados. Embora ambos adsorventes tenham apresentado boa capacidade de remoção do soluto, a resina trocadora de íons ainda apresentou resultado mais eficaz para as amostras reais. Nas condições desse estudo, a taxa de corrosão do aço nas amostras sintéticas e em duas das reais não foi significativa e apenas uma delas apresentou-se corrosiva (Óleo 1). No entanto, a remoção dos ácidos naftênicos por adsorção conseguiu reduzir a taxa de corrosão neste meio em até 99%
Naphthenic acids comprise a complex mixture of carboxylic acids that are present in petroleum. They are directly responsible for the oil acidity and its corrosiveness in liquid phase during the refining process. Such compounds are also presents in the derivatives, causing several problems to product quality. A possible way of removing these acids from those oil fractions is using the adsorption process in porous solids. Nevertheless, results presented so far show that ion exchange resins would be the best adsorbent for these acids, which could make this process very expensive. In this work, two commercial adsorbents (clay and activated alumina) were characterized by several physical-chemistry techniques and evaluated concerning their capacity of removing naphthenic acids from average and heavy fractions of crude oil. For comparison the behavior of commercial naphthenic acids in synthetic commercial samples prepared with mineral oil was also evaluated. In addition, the carbon steel corrosiveness in the studied systems was verified. Clay adsorbent presented better affinity with the acids, showing a greater capacity and a faster kinetics than alumina for synthetic oils. However, because of the higher competition with the other components present in real oils for the adsorption sites, a loss of efficiency for these samples was observed. In that case, alumina showed better results. Although both adsorbents have showed good capacity of removal of acids, the ion exchange resin still presented the best results for real samples. At the conditions of this study, the steel corrosiveness in the synthetic oils, as well as the data obtained for two of the real ones, was not significant, and only one of the real samples (Oil 1) corroded the carbon steel coupon. However, the naphthenic acid removal was able to reduce the corrosiveness in this medium up to 99%

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The naphthenic acids comprise a complex mixture of carboxylic acids that are present in petroleum. They are directly responsible for the oil acidity and its corrosiveness in liquid phase during the refining process. Such compounds are also presents in the derivatives, causing several problems to product quality. A possible way of removing these acids from those oil fractions is using the adsorption process in porous solids, as activated carbons. There are few studies about the removal of naphthenic acids on coals. For this reason, we chose four types of activated carbons for adsorption tests, and they coal babassu, palm kernel, coconut and of Bahia ox bone. In order to assess the possibility of further removing acidic compounds, the four carbons were subjected to a chemical treatment with concentrated sodium hydroxide. Physical and chemical analyzes were performed in order to promote the characterization of all adsorbents, showing that the treatment previously mentioned was leading to an increase in the adsorption capacity of the coals. The adsorption experiments with commercial batch naphthenic acid solution showed that the treated ox bone char had the highest retention efficiency, which is the adsorbent used to construct the adsorption isotherms. The isotherms were better adjusted by Langmuir model, revealing the chemisorption of character adsorptive process. The thermodynamic data showed that the process is spontaneous and endothermic, is favored by increasing the temperature. Regarding the crude oil sample, batch adsorption experiments were conducted in such a way as to determine the removal efficiency of class O2 and reducing the Total Acid Number (IAT). The results spectrometry FTICR ix MS Pasta, they showed that all coals chemically treated were able to remove more acidic compounds in relation to their untreated related. The raw coals babassu oil, palm oil and coconut Bahia showed a potential for adsorption of nitrogen compounds from oil, given that there was a decrease in its class in the class chart. As a final analysis, all the coals were evaluated for their ability to lower oil IAT, it was found that the ox bone char treated again achieved the best result, reducing by 70% the value of the IAT.
Os ácidos naftênicos correspondem à complexa mistura de ácidos carboxílicos presentes no petróleo, responsáveis diretamente pela sua acidez e pela sua corrosividade em fase líquida durante o refino. Tais compostos também estão presentes nas frações destiladas do petróleo, causando diversos problemas na qualidade final do produto. Uma alternativa para a remoção desses ácidos das frações destiladas é por meio da adsorção em materiais porosos, como os carvões ativados. Poucos são os estudos a respeito da remoção de ácidos naftênicos em carvões. Por esta razão, foram escolhidos quatro tipos de carvões ativados para os ensaios de adsorção, sendo eles carvão de babaçu, dendê, coco da Bahia e osso de boi. A fim de avaliar a possibilidade de uma maior remoção de compostos ácidos, os quatro carvões foram submetidos a um tratamento químico com solução concentrada de hidróxido de sódio. Análises físico-químicas foram realizadas com o intuito de promover a caracterização de todos os adsorventes, revelando que o tratamento anteriormente citado foi preponderante para um aumento na capacidade adsortiva dos carvões. Os ensaios de adsorção em batelada com solução comercial de ácidos naftênicos mostraram que o carvão de osso de boi tratado apresentou a maior eficiência de retenção, sendo este o adsorvente utilizado para a construção das isotermas de adsorção. As isotermas foram melhor ajustadas pelo Modelo de Langmuir, revelando o caráter de quimiossorção do processo adsortivo. Os dados termodinâmicos mostraram que o processo é espontâneo e endotérmico, sendo mais favorecido pelo aumento da temperatura. Em relação à amostra de petróleo bruto, ensaios de adsorção em batelada foram conduzidos de tal forma a averiguar a eficiência na remoção da classe O2 e na redução do Índice de Acidez Total (IAT). Os resultados de Espectrometria de Massas FT-ICR MS, mostraram que todos os carvões tratados quimicamente conseguiram remover mais compostos ácidos em relação a seus correlatos não tratados. Os carvões brutos de babaçu, dendê e coco da Bahia apresentaram uma potencialidade para adsorção de compostos nitrogenados do petróleo, haja vista que houve a diminuição desta classe no gráfico de classes. Como análise final, todos os carvões foram avaliados quanto suas capacidades de redução do IAT do petróleo, em que foi constatado que o carvão de osso de boi tratado novamente conseguiu o melhor resultado, reduzindo em 70% o valor do IAT.

Orientadores: Marcos Nogueira Eberlin, Eugenio Vaz dos Santos Neto
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química
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Resumo: Este trabalho consistiu na aplicação de tecnologia que se encontra hoje na vanguarda do conhecimento: a Petroleômica via ESI FT-ICR MS, com o objetivo de caracterizar as mais diversas classes de compostos polares ácidos presentes em amostras representativas de óleos de bacias brasileiras. O propósito ambicioso foi o de focalizar aspectos relacionados à toda cadeia de valor da indústria do petróleo, desde a geração do óleo até o seu refino, visando contribuir para novos estudos de interesse às atividades de upstream e downstream da PETROBRAS e, principalmente, fomentar a integração dos conhecimentos das diferentes áreas, o que contribuirá para ganhos de produtividade da empresa. A técnica ESI FT-ICR-MS mostrou-se uma técnica rápida e adequada para acompanhar as alterações verificadas na composição de amostras de petróleo, fornecendo subsídios a partir de uma caracterização única, para estudos diversos, abrangendo toda a cadeia de valor da indústria do petróleo. As alterações composicionais de óleos e extratos obtidos em experimentos de maturação artificial por hidropirólise de matéria orgânica dos tipos I e III foram avaliadas, evidenciando o potencial da técnica para utilização em estudos cinéticos. O estudo de biodegradação utilizando trinta amostras de óleos da Bacia Potiguar evidenciou que a técnica é sensível as variações de composição dos compostos polares que ocorrem em função do processo de biodegradação, e as amostras puderam ser agrupadas de acordo com o grau de biodegradação através da utilização de ferramentas quimiométricas (PCA). A partir dos dados de caracterização obtidos por ESI FT-ICR MS, foi possível agregar informações úteis para o entendimento de comportamentos diferenciados frente à tendência de formação de emulsão/gel durante a produção e frente à corrosão durante o refino
Abstract: This work focuses on the application of a technology that is cutting edge: Petroleomics by ESI FT-ICR MS with the goal of characterizing the large variety of acidic polar compound classes present in representative petroleum samples from Brazilian basins. The ambitious proposal was to focus on aspects related to the whole petroleum industry chain, since crude oil generation up to its processing in refinery units, to contribute to state-of-the-art studies of interest to upstream and downstream activities in PETROBRAS and mostly to encourage the knowledge integration, i.e. to form or blend the information into a whole, to UNITE, accessing high levels of productivity. The ESI FT-ICR MS technique exhibits characteristics like fast response, resolution, selectivity and sensibility, which make it suitable to monitor the changes in composition of petroleum samples and because of its unique and comprehensive characterization attained, to help different studies in the whole petroleum industry chain. The compositional alteration observed in extracts and oils during artificial maturation experiments by hydrouspyrolysis of organic matter types I and III were evaluated showing the potential of the technique to kinetic studies. Biodegradation studies were performed on 30 petroleum samples from Potiguar Basin and the results showed that the technique is sensitive to the variations on the composition of the polar compounds that occur as a result of the biodegradation process, and additionally, that the samples can be grouped according to their biodegradation level by the use of chimiometric tools (PCA). Also from the characterization data from ESI FT-ICR MS analysis it was shown that very useful information can be provided to better understand the differences in the rheological and corrosion behaviors of petroleum samples
Doutorado
Quimica Analitica
Doutora em Ciências

Current mining operators in the Athabasca oil sands deposit of Alberta, Canada have made commitments to zero discharge of oil sands process-affected waste materials (OSPM) from the mine site and rehabilitation of mined lands to a pre-mining state. As part of aquatic reclamation efforts, experimental test sites that contain a range of OSPM (solid and liquid components) were constructed to monitor the evolution and viability of aquatic habitats used as disposal sinks for OSPM produced by mining activities. In the present study, stable isotopes of carbon, nitrogen and sulphur were used to gauge some of the potential effects of OSPM site construction methods on aquatic food webs. Carbon and nitrogen isotopic signatures of sediment, dissolved inorganic carbon, dissolved organic carbon, particulate organic matter, periphytic material, plants, plankton, aquatic invertebrates and fish were used to assess differences related to the naphthenic acid (NA) concentration in OSPM and reference sites. For statistical analyses, sites were grouped into low (0 to 4 mg/L), medium (4 to 15 mg/L) and high (> 15 mg/L) NA concentrations. There were no significant differences in food web area or food web length among the low, medium and high NA concentration sites. In most cases, sample carbon isotope analyses of low, medium and high NA concentration sites were not significantly different, suggesting food web carbon sources did not include significant contributions from OSPM materials at OSPM sites. Significant differences, however, were found in the sample nitrogen isotope signatures between low, medium and high NA concentration sites. Ammonia from OSPM is suggested to be the main contributor to δ¹⁵N enrichment.

To determine the potential effects of site construction and OSPM within experimental test sites, carbon and sulphur stable isotopes of water, plankton, aquatic invertebrates and fish were analyzed. With the exception of Chaoborus and Haliplus, all carbon isotope signatures were not significantly different in constructed and reference sites. Also with the exception of Haliplus, sulphur isotope values for aquatic organisms from constructed and reference sites were significantly different. Aquatic organisms and water samples from constructed sites built in, or close, to the boundary of Kcw clays typically had δ³⁴S < 0 ?. Coinciding with depleted δ³⁴S signatures found in these aquatic systems were elevated sulphate concentrations. The waters at experimental test sites are in direct contact with the soil materials that facilitate the accumulation of sulphates as a result of the oxidation of substrate sulphide minerals. In general the results of the study suggest that aquatic food web structure and function do not change with the introduction of OSPM. Shifts in isotopic signatures suggestive of changes in food web structure, however, do occur when site construction exposes Kcw clays in the substrate.

La formation d'émulsions eau-dans-huile stables est un problème majeur rencontré par les pétroliers au niveau de la production mais aussi du raffinage. Afin d'essayer de prévoir ce phénomène, Total a développé une méthode de classement des huiles qui permet, à partir de leurs propriétés physico-chimiques, de déterminer a priori leur capacité à former ou non des émulsions stables. Cependant, les mécanismes interfaciaux sous-jacents ainsi que l’influence des molécules tensioactives du brut sur la stabilité des émulsions n’est pas très clair. Notre travail a consisté à étudier la contribution des acides naphténiques et des asphaltènes dans les phénomènes observés. L’étude d’huiles réelles a permis d’établir un lien entre la stabilité des émulsions et la formation à l'interface d'un gel 2D. Les études menées sur les huiles réelles dont les acides naphténiques ont été extraits ont permis de montrer que ces derniers, en compagnie de leurs formes ionisées, les naphténates, ont la capacité de réduire la stabilité des émulsions en diminuant la résistance du gel interfacial, ou même en empêchant sa formation. Les expériences réalisées sur les huiles réelles dépourvues d’asphaltènes ont permis de confirmer le rôle stabilisant des asphaltènes. Les résultats obtenus suggèrent que les asphaltènes s’adsorbent sur le gel 2D déjà formé par des tensioactifs passés de l’huile vers l’eau et le rapprochent ainsi de sa transition vitreuse. La résistance du gel interfacial s'en trouve alors augmentée, ce qui conduit à la formation d'émulsions plus stables. En croisant le classement industriel des bruts opéré par Total et les résultats de l’étude, un mécanisme global, régi par la compétition entre les acides naphténiques, les naphténates et les asphaltènes à l’interface E/H est proposé pour expliquer les différences de stabilité observées avec les différentes huiles. Lorsque les acides et les naphténates sont suffisamment concentrés, ils empêchent la formation du gel interfacial et les émulsions sont peu stables. Lorsqu’ils sont moins concentrés le rôle des asphaltènes peut alors devenir prépondérant en donnant une cohésion plus importante au gel qui se rapproche de sa transition vitreuse, ce qui conduit en général au renforcement de la stabilité des émulsions formées
Water-in-crude oil emulsions are a major issue for oil companies in both production and refining facilities. Thanks to physical and chemical characterizations, Total set a classification which allows the decision of a crude oil ability to create stable emulsions. However the interfacial mechanisms implied and the influence of the indigenous surfactants of crude oil remain unclear. Our work consists in studying the naphthenic acids and asphaltenes contribution to the w/o emulsion stability. The study of realistic crude oils enabled the discovery of a link between the emulsion stability with the formation of a very particular interfacial behavior: a two-imensional gel. Experiments with desacidified oils have proven the destabilizing ability of naphthenic acids and their ionized form, naphthenates. They actually decrease the interfacial gel strength and can even prevent the gel formation. Asphaltenes-free crude oils have permitted to confirm the stabilizing role of asphaltenes. Rather than adsorbing directly on the interface, asphaltenes seem to adsorb on the interfacial gel already formed. The gel strength is thus increased and lead to higher emulsion stability. Thanks to these results and the industrial classification of crude oil developed by Total, a global mechanism explaining the emulsion stability process has been proposed. This mechanism is governed by the competition between asphaltenes, naphthenates and naphthenic acids at the water/oil interface. If the concentration of naphthenic acids and naphthenates is high enough, the interfacial gel cannot be formed and the emulsions are unstable. If the crude oil is not acidic enough, the asphaltenes influence increases dramatically and implies the strengthening of the gel which becomes closer to his glass transition. This generally leads to the formation of more stable emulsions

Predviđena istraživanja u ovoj doktorskoj disertaciji su usmerena upravcu iznalaženja novih, efikasnijih i bržih mikrotalasno-stimulisanihmetoda hemijskih transformacija koje ne uključuju prisustvokatalizatora i/ili organskih rastvarača. Primenom specijalnih silicijum-karbidnih reakcionih sudova, brzina i preciznost izvođenjamikrotalasno-stimulisanih transformacija prikazana  je kroz stresnestudije aktivnih farmaceutskih ingredijenata u SiC  ploči, odnosnoHPLC/GC vialima kao reakcionim sudovima. Ispitano je postojanjenetermičkih mikrotalasnih efekata i njihov značaj za precizno tumačenjerezultata mikrotalasne sinteze.U drugom delu ove doktorske disertacije izvršena jemikrotalasno-stimulisana sinteza potencijalno biološki aktivnih  supstanci iz prirodnihlako dostupnih materijala kao što su naftenske kiseline. Sintetizovani suamidi i estri individualnih i prirodnih naftenskih kiselina Velebit.U radu je takođe ispitana biološka aktivnost sintetizovanih derivata.Proučavan je uticaj prirodnih naftnih kiselina Velebit injenih derivatana rast pet sojeva  Pseudomonassp., kao i uticaj odabranih sintetisanihjedinjenja na proliferaciju pet  ćelijskih linija humanih tumora pri  čemuje kao kontrola služila jedna zdrava humana ćelijska linija.
Scientific research predicted in this PhD thesis isdirected to ascertainment new, efficient and faster microwave-assisted methods of chemical transformations in the absence of catalysts and/or organic solvents. Applaying special silicon-carbide  reaction vessels, speed and accuracy of microwave-assisted transformations are ilustrated within stress testing of active pharmaceutical ingredients in HPLC/GC vials placed in SiC plate. Existence of nonthermal microwave effects and their influence on  accurate interpretation of microwave synthesis results are also investigated. In the second part of this thesis microwave-assisted synthesis of potentionally biologically active compounds from readily available natural materials, such as  naphthenic acid is accomplished. Amides and esters of individual and natural naphthenic acids Velebitare synthetised. The thesis also examined the biological activity ofthe synthesized products. The effect of natural petroleum acids  Velebitand its derivatives are examined on the growth of five strains of Pseudomonas sp., and the impact of selected synthesized compounds on the proliferation of five human tumor cell lines in which a healthy human cell line is tused as the control.

Cette thèse comporte deux parties indépendantes. La première étude présente les premiers exemples de métallation de la structure azobenzène par les réactifs organométalliques polaires. Largement utilisés en tant que colorants, les azobenzènes trouvent actuellement de nombreuses applications dans le domaine des matériaux en raison de leur facile photoisomerisation E/Z. Il est montré que les bases organométalliques polaires classiques (n-BuLi, n-BuLi/TMEDA, n-BuLi/t-BuOK, TMPMgCl.LiCl, LDA) ne métallent pas l’azobenzène parent mais réduisent plutôt la liaison N=N. Cependant la métallation est possible avec le tétraméthylpipéridure de lithium si un groupement directeur de métallation tel que le méthoxy (OMe), diéthylamide (CONEt2) ou fluoro (F) est présent sur l’azobenzène. La réaction permet un accès original et direct à de nouveaux azobenzènes substitués. L’objectif de la deuxième partie est la synthèse de dérivés biaryliques chiraux en l’absence de métaux de transition (Pd, Ni…). Les biaryles chiraux sont présents dans de nombreuses molécules biologiquement actives et peuvent être utilisés comme ligands pour la catalyse asymétrique. La substitution nucléophile aromatique des acides naphtoïques en présence de ligands chiraux a été étudiée. Une optimisation fine des conditions réactionnelles (choix du solvant, température, structure du ligand…) a permis de préparer des 1,1’-binaphtalènes, 1,2’-binaphtalènes et phénylnaphtalènes avec de bons rendements et excès énantiomériques (jusqu’à 89% ee). La substitution nucléophile aromatique atroposélective de dérivés d’acides naphtoïques de type naphtyloxazolines et naphtoates est également décrite
This thesis is divided into two independant parts. The first part describes for the first time the chemoselective lithiation of azobenzenes. Azobenzenes derivatives are widely used as dyes and more recently have been applied to the preparation of photoresponsive molecular switches and materials by taking advantage of the N=N bond E/Z photoisomerization. Whereas standard polar organometallics (n-BuLi, n-BuLi/TMEDA, n-BuLi/t-BuOK, TMPMgCl.LiCl, LDA) reduce the N=N bond of the parent compound, aromatic HLi permutation occurs with LTMP when a suitable director of lithiation (OMe, CONEt2, F) is present in the benzene residue of the azo compound. The method allows a direct access to new substituted azobenzenes.Axially chiral biaryls, which are found in many biologically active natural products, are conventionally used as ligands for asymmetric catalysis. The purpose of the second part is to develop a new method for the preparation of axially chiral biaryls in the absence of transition metals (Pd, Ni…). To tackle that goal, nucleophilic aromatic substitution reactions on unprotected naphthoic acids were performed in the presence of chiral ligands. A careful optimization of the reaction parameters (choice of the solvent, temperature, structure of the ligand…) allowed to prepare chiral 1,1’- binaphthalenes 1,2’- binaphthalenes and phenylnaphthalenes in good yields and enantiomeric excesses (up to 89% ee). The atroposelective SNAr reaction of naphthyloxazoline and naphthoate derivatives was also reported

Dans ce travail, il est montré que les alkyl/vinyl/aryl lithiens et magnésiens réagissentavec les acides C-1(F/OMe) naphtoïques en l'absence de catalyseur métallique. Cette nouvelleréaction de substitution nucléophile aromatique permet potentiellement de préparer n'importequel biaryle tout en s'affranchissant des étapes de protection et de déprotection de la fonctionacide (CO2H). Les alkyllithiens linéaires et ramifiés réagissent avec la même efficacité que lesalkylmagnésiens même à basse température (-78 °C). Le déplacement d'un fluor ou d'unméthoxy s'effectue avec la même facilité. L'absence d'ortho-lithiation est confirmée par lepiégeage du milieu réactionnel en fin de réaction par l'iodométhane (après addition de n-BuLi,s-BuLi et t-BuLi). Le bromure de vinylmagnésium requiert un chauffage au reflux du THF.La méthode étudiée permet de préparer extrêmement facilement des 1- et 2-phénylnaphtalènes, 1,1'-binaphtalènes et 2,2'-binaphtalènes. Dans les exemples où lesaryllithiens donnent des rendements moyens-faibles en produits de couplage, les réactifs deGrignard sont beaucoup plus efficaces. Le o-tolyllithium, le bromure de o-tolylmagnésium, lebromure de (4-méthoxyphényl)magnésium, le bromure de (2,5-diméthylphényl)magnésium etle bromure de benzo[d][1,3]dioxol-5-ylmagnésium déplacent facilement le groupefluoro/méthoxy en ortho du groupe CO2M pour donner les produits de substitutioncorrespondants alors que la réaction du bromure de (2,6-diméthoxyphényl)magnésium estmoins efficace sans doute en raison de l'encombrement stérique causé par les deux groupesortho-méthoxy. L'acide 1-(2-méthoxyphényl)-2-naphtoïque est un produit particulièrementintéressant. La déprotection du groupe méthoxy suivie d'une cyclisation est réalisée par BBr3pour donner la 6H-naphtho[2,1-c]chromén-6-one qui est isolée avec un rendement de 97 %.Cette lactone est utile pour la préparation de composés atropoisomères optiquement actifsaprès ouverture énantiosélective du cycle lactone selon la technique mise au point parBringmann.

Циљ савременог гајења јабуке је да се у засаду велике густине садње, заснованом са садницама високог квалитета које рађају већ у години садње, и савременим сортиментом који укључује и сорте склоне алтернативној родности, успоставе редовни и високи приноси који ће се кретати од 50-70 t/ha и добар квалитет плодова. Мера која је од највећег значаја за регулисање родности јесте хемијско проређивање цветова и плодова јабуке.Циљ обављених истраживања је да се испита утицај хемијског проређивања цветова и плодова на заметање, квалитет плодова и родност пупољака сорти јабуке као и да се испита интеракција између минералне исхране азотом и хемијског проређивања. Резултати истраживања били би смернице за хемијско проређивање плодова у агроеколошким условима Србије, са тежњом да у скорој будућности постану део законске регулативе и припадајућих правилника за интегралну производњу, као и развој побољшаних формулација препарата за проређивање.На основу испитивања проређивања цветова може се закључити да сорте јабуке бребурн и златни делишес различито реагују на примену ATS и KTS. Примена 3% ATS и 1,5% KTS код сорте бребурн изазива јаке ожеготине на листовима које могу бити узрок смањеној маси плода и слабијем образовању родних пупољака. Код сорте златни делишес ATS концентрације 3% не испољава негативно дејство на крупноћу плодова и родност пупољака, али са друге стране није ефикаснији од ATS нижих концентрација, док KTS има знатно слабије дејство.Ефикасност препарата на бази NAA у смањењу заметања и приноса сорте јабуке бребурн није зависила од примењене концентрације, док је маса плода у свим варијантама била веома велика, те се за практичну примену могу препоручити ниже концентрације, до 10 μl/l NAA. Сви третмани са NAA у распону концентрација од 8 до 12 μl/l били су једнако ефикасни у редуковању заметања и приноса плодова, док је BA испољио слабију ефикасност у проређивању сорте јабуке камспур. Родност пупољака у третманима проређивања плодова сорти бребурн и камспур није сразмерна повећању концентрације препарата, већ у великој мери зависи од године испитивања.Значајна интеракција је утврђена између фактора ђубрење и проређивање за параметре заметања плодова. Интеракција ова два фактора огледа се у томе да се у режиму интензивног ђубрења азотним ђубривима концентрација препарата на бази NAA и BA треба повећати како би се постигао задовољавајући ниво проређивања.Додавање нафтенских киселина нафтилсирћетној киселини и бензиладенину значајно доприноси повећању просечне масе плода сорте јабуке златни делишес у односу на формулације без нафтенских киселина, као последица биолошке активности нафтенских киселина у смеши. Запажено је повећање чврстине плода у варијантама где је примењена формулација BA са нафтенским киселинама у односу на формулације безнафтенских киселина.Датум прихватања теме од стране Сената:ДП30.5.2013.Чланови комисије:
Cilj savremenog gajenja jabuke je da se u zasadu velike gustine sadnje, zasnovanom sa sadnicama visokog kvaliteta koje rađaju već u godini sadnje, i savremenim sortimentom koji uključuje i sorte sklone alternativnoj rodnosti, uspostave redovni i visoki prinosi koji će se kretati od 50-70 t/ha i dobar kvalitet plodova. Mera koja je od najvećeg značaja za regulisanje rodnosti jeste hemijsko proređivanje cvetova i plodova jabuke.Cilj obavljenih istraživanja je da se ispita uticaj hemijskog proređivanja cvetova i plodova na zametanje, kvalitet plodova i rodnost pupoljaka sorti jabuke kao i da se ispita interakcija između mineralne ishrane azotom i hemijskog proređivanja. Rezultati istraživanja bili bi smernice za hemijsko proređivanje plodova u agroekološkim uslovima Srbije, sa težnjom da u skoroj budućnosti postanu deo zakonske regulative i pripadajućih pravilnika za integralnu proizvodnju, kao i razvoj poboljšanih formulacija preparata za proređivanje.Na osnovu ispitivanja proređivanja cvetova može se zaključiti da sorte jabuke breburn i zlatni delišes različito reaguju na primenu ATS i KTS. Primena 3% ATS i 1,5% KTS kod sorte breburn izaziva jake ožegotine na listovima koje mogu biti uzrok smanjenoj masi ploda i slabijem obrazovanju rodnih pupoljaka. Kod sorte zlatni delišes ATS koncentracije 3% ne ispoljava negativno dejstvo na krupnoću plodova i rodnost pupoljaka, ali sa druge strane nije efikasniji od ATS nižih koncentracija, dok KTS ima znatno slabije dejstvo.Efikasnost preparata na bazi NAA u smanjenju zametanja i prinosa sorte jabuke breburn nije zavisila od primenjene koncentracije, dok je masa ploda u svim varijantama bila veoma velika, te se za praktičnu primenu mogu preporučiti niže koncentracije, do 10 μl/l NAA. Svi tretmani sa NAA u rasponu koncentracija od 8 do 12 μl/l bili su jednako efikasni u redukovanju zametanja i prinosa plodova, dok je BA ispoljio slabiju efikasnost u proređivanju sorte jabuke kamspur. Rodnost pupoljaka u tretmanima proređivanja plodova sorti breburn i kamspur nije srazmerna povećanju koncentracije preparata, već u velikoj meri zavisi od godine ispitivanja.Značajna interakcija je utvrđena između faktora đubrenje i proređivanje za parametre zametanja plodova. Interakcija ova dva faktora ogleda se u tome da se u režimu intenzivnog đubrenja azotnim đubrivima koncentracija preparata na bazi NAA i BA treba povećati kako bi se postigao zadovoljavajući nivo proređivanja.Dodavanje naftenskih kiselina naftilsirćetnoj kiselini i benziladeninu značajno doprinosi povećanju prosečne mase ploda sorte jabuke zlatni delišes u odnosu na formulacije bez naftenskih kiselina, kao posledica biološke aktivnosti naftenskih kiselina u smeši. Zapaženo je povećanje čvrstine ploda u varijantama gde je primenjena formulacija BA sa naftenskim kiselinama u odnosu na formulacije beznaftenskih kiselina.Datum prihvatanja teme od strane Senata:DP30.5.2013.Članovi komisije:
The goal of modern apple growing in high density orchards, established with high-quality nursery trees which bear fruits in the year of planting, often including varieties prone to biennial bearing is to achieve high and regular yields that range from 50 to 70 t/ha with good fruit quality. Chemical thinning of flowers and fruits is a technical practice which is of great importance for crop regulation.The aim of the research was to investigate the effect of chemical thinning of apple flowers and fruits on fruit set, fruit quality and bearing potential of apple buds as well as to examine the interaction between the nitrogen supply and chemical thinning treatments. The research will result with guidelines for the chemical thinning in agroecological conditions of Serbia, aiming to become a part of the legislation and associated regulations for integrated production in the near future. Testing of improved formulations of thinning chemicals will be included into expe rimental plan.Considering the results derived from flower thinning experiments, it could be concluded that cv. Braeburn and Golden Delicious react differently to the application of ATS and KTS. Application of 3% ATS and 1.5% of KTS in cv Braeburn causes severe leaf burns that may be causing reduced fruit weight and a decrease in bearing potential. In cv Golden Delicious ATS applied at the concentration of 3% does not exhibit a negative effect on fruit size and bearing potential, but at the other side is not more efficient than ATS at lower concentrations, whereas KTS has a much weaker thinning effect.The efficacy of NAA in reducing fruit set and yield of apple variety Braeburn is not dependent on the concentration applied, while fruit size was very large within the range of NAA concentrations. Therefore, for the practical application, concentrations lower than 10 ml/l NAA would be recommended. All treatments with NAA at concentrations ranging from 8 to 12 ml/l were equally effective in reducing fruit set and yield, while the BA exhibited decreased efficiency in thinning apple variety Camspur. Fertility of buds in Braeburn and Camspur varieties was not proportional to the increase in concentration of chemical, but to a large extent depends on the conditions of the experimental year.An interaction between nitrogen supply and chemical thinning significantly affected fruit set in a way that concentration of NAA and BA for fruit thinning should be increased in order to achieve a satisfactory level of thinning at a higher level of nitrogen supply.Adding of naphthenic acids to NAA and BA significantly contributed to the increase of average fruit weight of apple variety Golden Delicious compared to same chemical formulation without naphthenic acids, as a result of the biological activity of naphthenic acids in the mixture. An increase of fruit firmness was detected in thinning treatments where naphthenic acids were added to BA compared BA applied alone.

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O petróleo é uma mistura complexa, sendo uma das misturas mais desafiadoras para as análises químicas. Muitas técnicas são empregadas para a caracterização dos constituintes do óleo. Entretanto, quando combinamos o altíssimo poder de resolução e exatidão da espectrometria de massas, em especial a Ressonância Ciclotrônica de Íons com Transformada de Fourier, (FT-ICR MS) com fontes de ionização a pressão atmosférica, uma atribuição precisa de mais de 20 000 compostos orgânicos do petróleo pode ser obtida. Na indústria do petróleo existe um grande interesse na análise de ácidos naftênicos e asfaltenos devido a problemas como corrosão e formação de depósitos, que aumentam os custos de produção. Portanto este trabalho tem como objetivo a avaliação da termodegradação de ácidos naftênicos, além do emprego das fontes de ESI, APCI, APPI, LDI e MALDI para aquisição de novos dados relativos a caracterização de asfaltenos. Dois petróleos foram utilizados nos ensaios de termodegradação, o petróleo A com acidez de 2,38 mg KOH g-1 e o petróleo B com 4,79 mg KOH g-1 os quais foram tratados a 280, 300 e 350 ºC pelo período de 2, 4 e 6 horas. De uma maneira geral, as principais classes identificadas para ambas às amostras foram O2, N e NO2, respectivamente. Uma leve redução do NAT e da abundância relativa referente à classe O2 foram observado em função da temperatura e do tempo de envelhecimento (T = 280 → 300 oC e t = 2 → 6 h), sendo que a temperatura de tratamento térmico a 350 ºC demonstrou-se determinante na remoção de compostos da classe O2. O perfil químico de amostras de asfaltenos brasileiros foi avaliado utilizando-se cinco diferentes métodos de ionização em ambos os modos de ionização: positivo e negativo, depois, a distribuição de peso molecular, distribuição de classe, parcelas típicas de número de carbono contra DBE e diagramas van Krevelen foram obtidos e discutidos. Um comportamento atípico foi observado para a fonte de LDI e MALDI (±) FT-ICR MS. Um amplo perfil, de m/z 500-3000, apresentando espaçamento de 24 Da foi observado, e este corresponde a formas alotrópicas de fulereno, C60. Em geral, os asfaltenos apresentaram um elevada proporção de espécies heteroatómicas como: HC, HC [H], N, N [H], N2O, N2O [H], N2, N2 [H], O, O[H] para o modo (+) e N, N [H], NO, NO [H], NO, NO2[H], N2O, N2O[H] para o modo negativo. Nos diagramas de DBE contra o número de carbono, os asfaltenos mostraram para cada valor de DBE uma pequena amplitude de compostos com respeito à NC, proporcionando assim, imagens que formam uma linha de 45 ° entre os eixos CN e DBE. Isto indica que estes compostos não exibem grandes cadeias de alquílicas, sendo composta principalmente por anéis aromáticos. Em geral os diagramas de van Krevelen mostraram alta proporção de compostos com razão H/C ~0,7, corroborando com a existência de espécies altamente aromáticas
Petroleum is a complex mixture, being one of the most challenging mixtures for chemical analyzes. Many techniques are employed to characterize constituents of the oil. However , when we combine the highest resolving power and accuracy of mass spectrometry , especially Ion Cyclotron Resonance Fourier Transform ( FT - ICR MS ) with sources of atmospheric pressure ionization , an assignment need more than 20 000 organic compounds in the oil can be obtained. In the oil industry there is a great interest in the analysis of asphaltenes and naphthenic acids due to problems such as corrosion and deposit formation, which increases production costs. Therefore this study aims to evaluate the thermodegradation of naphthenic acids, besides the use of sources of ESI, APCI, APPI, MALDI and LDI for the acquisition of new data on the characterization of asphaltenes . Two test oils were used in thermodegradation of the oil with an acidity of 2.38 mg KOH g -1 and Oil B with 4.79 mg KOH g- 1 which were treated at 280 , 300 and 350 ° C for a period of 2 , 4 and 6 hours. Generally, the major classes identified for both samples O2, NO2, and C, respectively. A slight reduction of NAT and relative abundance refers to the class O2 were observed as a function of temperature and aging time (T = 280 → 300 ° C t = 2 → 6 h), and the heat treatment temperature at 350 ° C showed a determinant for the removal of class O2. The chemical asphaltenes Brazilian samples was evaluated using five different methods of ionization in both modes of ionization: positive and negative, then the molecular weight distribution, distribution class, typical plots versus carbon number and DBE van Krevelen diagrams were obtained and discussed. An unusual behavior was observed for the LDI and MALDI source ( ± ) FT - ICR MS . A comprehensive profile of m / z 500-3000, with spacing of 24 Da was observed, and this corresponds to allotropes of fullerene C60. In general, the asphaltenes had an heteroatómicas high proportion of species such as HC , HC [ H] , N, [ H] , N2O N2O [ H] N2, N2 [ M ] O O [ H] to mode (+) and N, [ H ] , NO [ H] , NO , NO2, [ H] , N2O N2O [ H ] for the negative mode . In the diagrams DBE against the carbon number , the asphaltenes shown for each value of DBE composed of a small amplitude with respect to NC, thus providing images that form a line of 45 ° between the axes CN and DBE. This indicates that these compounds do not exhibit large chain alkyl, composed mainly of aromatic rings. In general diagrams van Krevelen showed a high proportion of compounds ratio H / C ~ 0.7, confirming the existence of highly aromatic species

Oil sand deposits in the Athabasca Basin in Alberta represent one of the largest global oil reserves. The bitumen contents of oil sand shallow deposits are recovered by surface mining using modified version of the Clark hot water process. Extraction of bitumen results in extremely large volumes of process water, which are contaminated with naphthenic acids. Various ex-situ treatment techniques including ozonation, advanced oxidation, adsorption, and bioremediation have been evaluated for the treatment of these waters. Previous studies conducted by Paslawski et al. (2009) investigated aerobic biodegradation of naphthenic acids in properly designed and carefully operated bioreactors. In the current work, anaerobic biodegradation of naphthenic acids under denitrifying condition was examined as a potential approach to eliminate the aeration cost in ex-situ treatment and as an alternative for application of in-situ treatment of oil sand process water in stabilization ponds was examined. Using trans-4-methyl-1-cyclohexane carboxylic acid (trans-4MCHCA), a microbial mixed culture developed in earlier works (Paslawski et al., 2009), and nitrate as an electron acceptor, anaerobic biodegradation of trans-4MCHCA were studied in batch and continuous bioreactors: continuous stirred tank reactor (CSTR) and biofilm system. Effects of naphthenic acid concentration, temperature, and loading rate on biodegradation process were investigated. The batch studies showed that initial concentration of trans-4MCHCA influenced the biodegradation rate where the increase in initial concentration of trans-4MCHCA from 100 to 250 mg L-1 led to a higher rate but further increase in concentration did not have a marked effect. Moreover, batch experiments at temperatures ranging from 10° to 35°C demonstrated that the optimum temperature was in the range of 20 - 24°C. Continuous anaerobic biodegradation in the CSTR showed that increase in loading rate of trans-4MCHCA caused an increase in removal rate of both trans-4MCHCA and nitrate. Rates were decreased as the system approached the cell washout. The maximum biodegradation rate and nitrate removal rate, achieved at trans-4MCHCA loading rate of 157.8 mg L-1 h-1, were 105.4 mg L-1 h-1 and 144.5 mg L-1 h-1, respectively. A similar dependency between the loading and removal rates was also observed in the biofilm reactor. The maximum removal rate of trans-4MCHCA and nitrate in the biofilm reactor, operated at room temperature (24 ± 2ºC) were 2,028.1 mg L-1 h-1 and 3,164.7 mg L-1 h-1, respectively and obtained at trans-4MCHCA loading rate of 2,607.9 mg L-1 h-1. Comparison of the results from aerobic batch systems obtained by Paslawski et al. (2009) and the current results showed similar profile where increase in initial concentration of naphthenic acid increased the biodegradation rate of trans-4MCHCA. As far as the effect of temperature is concerned, room temperature (20 - 24ºC) was identified as optimum temperature regardless of mode of biodegradation. Under continuous mode of operation (CSTR and biofilm reactors), anaerobic biodegradation was much faster than its aerobic counterpart. For instance the maximum anaerobic removal rate of trans-4MCHCA in the CSTR was 105.4 mg L-1 h-1, while the highest removal rate achieved in the aerobic CSTR was 9.6 mg L-1 h-1. Similarly, anaerobic biofilm reactor achieved a higher maximum removal rate of 2,028.1 mg L-1 h-1 compared to a 924.4 mg L-1 h-1 removal rate in the aerobic biofilm reactor. The overall finding indicated that biodegradation of trans-4MCHCA can be achieved effectively under anaerobic condition with the rates markedly higher than those for aerobic system.

Extraction of bitumen from oil sands by surface mining and alkaline hot water process has generated large amount of oil sand process water (OSPW) which are contaminated by naphthenic acids (NAs). Due to the toxic and harmful nature of NAs, OSPW have been stored on-site in extremely large tailing ponds. With the understanding that the OSPW must be treated before their release into the natural water bodies and the need for reuse of the water, there is an urgent need in finding ways to treat these OSPWs effectively and economically. Numerous works on different treatment methods including photocatalysis, ozonation, adsorption, phytoremediation, simulated wetlands and bioremediation have been conducted and bioremediation has been proved as one of the most feasible ways among these methods. Research works on biodegradation of NAs, both aerobically and anoxically, have been conducted intensively in our research group in the past several years. Using surrogate NAs, specially trans-4-methyl-1-cyclohexane carboxylic acid (trans-4MCHCA), aerobic (Paslawski et al., 2009a,b,c, Huang et al., 2012; D’Souza et al., 2013) and anoxic (Gunawan et al., 2014) biodegradations of NA have been studied in batch, CSTR, biofilm system and circulating packed-bed bioreactor. Effects of naphthenic acid concentration, temperature, and naphthenic acid loading rate on the biodegradation process have been investigated. The results of the anoxic biodegradation of trans-4MCHCA in the presence of nitrate as an electron acceptor revealed that its performance was similar or better than the aerobic biodegradation. The results of that study also indicated the production of nitrite during the denitrification of nitrate and its subsequent consumption as part of biodegradation process. Given the importance of denitritation (nitrite reduction) as an essential step in anoxic biodegradation in the presence of nitrate, and the potential inhibitory effect of nitrite, the current research was conducted with the aim of investigating the performance of the anoxic biodegradation of trans-4MCHCA in the presence of nitrite as an electron acceptor, using batch, CSTR and biofilm reactors. The results of batch studies showed that nitrite at concentration up to 690 mg L-1 did not have a marked inhibitory effect but concentrations above 920 mg L-1 imposed a strong inhibitory effect. The optimum temperature was found to be in the range 24 C to 30°C. Continuous anoxic biodegradation of trans-4MCHCA with nitrite in CSTR achieved the maximum trans-4MCHCA biodegradation rate of 14.4 mg L-1 h-1 at a trans-4MCHCA loading rate of 22.9 mg L-1 h-1, which was about seven fold lower than the maximum trans-4MCHCA biodegradation rate observed with nitrate as an electron acceptor (105.4 mg L-1 h-1; Gunawan 2013). Both the trans-4MCHCA and nitrite degradation rates decreased with further increase of trans-4MCHCA loading rate. Using the experimental data the biokinetic coefficients Y (biomass yield), Ke (endogenous rate constant), μm (maximum specific growth rate) and Ks (saturation constant) were determined as 0.3 mg cell mg substrate-1, ~0 h-1, 0.4 h-1 and 20.9 mg substrate L-1, respectively. Similar pattern was observed in the biofilm system whereby the maximum trans-4MCHCA biodegradation rate was 82.2 mg L-1 h-1 at a trans-4MCHCA loading rate of 171.8 mg L-1 h-1, was about five folder lower than the maximum trans-4MCHCA biodegradation rate observed when nitrate was used as an electron acceptor (435.8 mg L-1 h-1; Gunawan 2013). The findings of current study suggested that the anoxic NA biodegradation in the presence of nitrite occurred at rates which were lower than those observed in the presence of nitrate, as well as those obtained under aerobic conditions with oxygen as the electron acceptor.

Two liquid-solid reactions, in which the morphology of the solid changes as the reactions proceeds, were examined. One is the NA conversion in oil by decarboxylation on metal oxides and carbonates, and the other is the Kraft pulping in which lignin removal by delignification reaction. In the study of the NA conversion, CaO was chosen as the catalyst for the kinetic study from the tested catalysts based on NA conversion. Two reaction mixtures, carrier oil plus commercial naphthenic acids and heavy vacuum gas oil (HVGO) from Athabasca bitumen, were applied in the kinetic study. The influence of TAN, temperature, and catalyst loading on the NA conversion and decarboxylation were studied systematically. The results showed that the removal rate of TAN and the decarboxylation of NA were both independent of the concentration of NA over the range studied, and significantly dependent on reaction temperature. The data from analyzing the spent catalyst demonstrated that calcium naphthenate was an intermediate of the decarboxylation reaction of NA, and the decomposition of calcium naphthenate was a rate-determining step. In the study on the delignification of the Kraft pulping, a new mechanism was proposed for the heterogeneous delignification reaction during the Kraft pulping process. In particular, the chemical reaction mechanism took into account the heterogeneous nature of Kraft pulping. Lignin reacted in parallel with sodium hydroxide and sodium sulfide. The mechanism consists of three key kinetic steps: (1) adsorption of hydroxide and hydrosulfide ions on lignin; (2) surface reaction on the solid surface to produce degraded lignin products; and (3) desorption of degradation products from the solid surface. The most important step for the delignification process is the surface reaction, rather than the reactions occurring in the liquid phase. A kinetic model has, thus, been developed based on the proposed mechanism. The derived kinetic model showed that the mechanism could be employed to predict the pulping behavior under a variety of conditions with good accuracy.
Chemical Engineering

A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, in fulfilment of the requirements for the degree of Master of Science in Engineering 16 November 2018
High temperature sulphidic (HTS) and naphthenic acid corrosion (NAC) pose not only reliability, but also health, safety and environmental threats to crude oil distillation unit operations. Based on an oil refinery’s crude oil diet properties, materials of construction and operational conditions in the distillation units, these high temperature corrosion phenomena occur in varying severity. In a bid to improve profit margins, oil refineries may choose to process opportunity crude oils at the risk of aggravating these corrosion mechanisms. In order to predict corrosion rates due to HTS and NAC, an industry corrosion model, Predict CrudeTM, was used on a refinery’s atmospheric and vacuum distillation units. The model was based largely on empirical data from a 4-year joint industry program that collected NAC and HTS corrosion rate data. The model provided qualitative corrosion rates for different distillation product streams for three model cases, based on total acid number (TAN) namely crude blend TAN 0.35, TAN 0.5 and TAN 0.8. The corrosion rates produced by the model for the 0.35 and 0.5 TAN cases were assessed against the measured corrosion rates, using conventional (industrial ultrasonic thickness and profile radiography) plant inspection techniques. Good agreement between the model predicted corrosion rates for the 0.35 and 0.5 TAN cases and the practically observed corrosion rates was found. The 0.8 TAN case was used to assess upset (unusual) conditions only, as the plant did not process 0.8 TAN crude blends. The 0.8 TAN case model data also explained some of the higher than modelled corrosion rates that were measured. Thus, the model provided a closely accurate prediction of corrosion rates to be expected in the atmospheric and vacuum distillation units.
E.R. 2019

To ensure oil sands process water (OSPW) is suitable for discharge into the environment, advanced water treatment technologies are required. In this study, integrated ozonation-biodegradation was investigated as a potential treatment option for OSPW. The treatment efficiency was evaluated in terms of naphthenic acid (NA) degradation, chemical oxygen demand (COD), carbonaceous Biological oxygen demand (CBOD), and acute toxicity reduction. Degradation of NAs of more than 99% was achieved using a semi-batch ozonation system at a utilized ozone dose of 80 mg/L combined with subsequent biodegradation. The results also show that ozone decreased the amount of COD while increasing the biodegradability of COD. It was noted that the carbon number and number of NA rings influenced the level of NA oxidation. With a utilized ozone dose of approximately 100 mg/L, the ozonated and biodegraded treated OSPW showed no toxic effect towards bacterium Vibrio fischeri. The results of this study indicate that integrated ozonation-biodegradation is a promising treatment technology for OSPW.
Environmental Engineering

碩士
國立中山大學
環境工程研究所
100
Spent caustic liquors (SCL) generated from crude oil refineries have characteristics of high COD (chemical oxygen demand) contents and relatively small generation rates as compared with general wastewater ones. The odorous naphthenates, phenolates, and sulfides in the liquors adversely affect the normal operation of the related wastewater treatment plants and effluent water qualities. This study aims at the reduction of COD in a naphthenic spent caustic liquor generated from a domestic refinery with crude processing and naphtha cracking units. Primary tests indicated that around 50% of the COD in the SCL could be biodegraded. Chemical oxidation methods were tried to possibly upgrade the COD removal. Experiments indicated that acidification of the SCL sample to pH 2-3 could reduce the COD from an average of 51,600 to 20,800 mg/L by removing the separated naphthenic acids. Fenton’s method with oxidants of 20 mL/L 35% H2O2 and FeSO4.7H2O 5 g/L, oxidation time of 1 hour at conditions of pH 2-3 and 80-100oC, could reduce the COD of the acidified SCL from an average of 20,800 to 11,100 mg/L. The overall COD removal was around 78% and the efficiency is comparable to that of a traditional Wet Air Oxidation (WAO) process of around 75%. Economic analysis indicated that for treating the SCL of 80 m3/day by the traditional WAO process, an initial equipment cost of 10 millions USD and annual operating cost of around 1.5 millions USD are required. By the developed acidification-Fenton’s process, an initial equipment cost of 0.7 million USD and annual operating cost of around 0.5 million USD are expected. The developed process can be superior to the WAO one.

Naphthenic acids (NAs), a group of compounds found in oil sands process-affected waters, have been implicated as a cause of the atypical odors which characterise fish taint. Sensory analyses were undertaken to clarify the role of NAs in fish taint. Triangle test and three-alternative forced choice (3-AFC) methods were used to estimate olfactory detection thresholds of NAs. Due to cognitive advantages, the 3-AFC method was found to be superior for the estimation of olfactory detection thresholds of NAs. 3-AFC analyses by trained panels of two commercial preparations and one oil sands extract of NAs, revealed that the odor detection thresholds and odor profiles of NAs differ markedly depending upon their source. Consumer preference panels revealed no evidence that the taste of fish collected from the Athabasca River was preferred less than the taste of fish from two other water basins in Alberta.
Food Science and Technology