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Dissertations / Theses on the topic 'Phenol'
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1
Tonge, Livia. "Thermochemical properties of methylol phenol monomers and phenol formaldehyde resoles." Swinburne Research Bank, 2007. http://hdl.handle.net/1959.3/47166.
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Thesis (PhD) - Swinburne University of Technology, Faculty of Engineering and Industrial Sciences, 2007.A thesis submitted for the degree of Doctor of Philosophy, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, 2007. Typescript. Includes bibliographical references.
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Janzen, Christoph. "Spektroskopische Strukturaufklärung der wasserstoffbrückengebundenen Cluster von Phenol mit Wasser, Ameisensäure und Essigsäure." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=960303952.
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Rubió, Piqué Laura. "Phenol-enriched olive oil with its own phenolic compounds and complemented with phenols from thyme: a functional food development model." Doctoral thesis, Universitat de Lleida, 2014. http://hdl.handle.net/10803/146133.
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L'enriquiment de l’oli d'oliva amb els seus propis fenols esdevé una estratègia interessant per augmentar i normalitzar la ingesta diària d’hidroxitirosol sense augmentar el consum calòric. No obstant això, olis amb alt contingut fenòlic proporcionen un gust amarg que podria provocar rebuig entre els consumidors. A més, altes dosis d'hidroxitirosol podria tenir una acció pro-oxidant. En aquesta tesi es va plantejar l'estratègia d'enriquiment d’un oli d'oliva no només amb els seus propis fenols, sinó amb fenols complementaris d'herbes aromàtiques, concretament de farigola, amb la hipòtesi de que apart de proporcionar millores en l'estabilitat de l'oli i l'acceptació dels consumidors, també podria aportar beneficis addicionals per a la salut. Un cop desenvolupat l'oli d'oliva enriquit en fenols, es va avaluar la biodisponibilitat dels fenols mitjançant mètodes in vitro i in vivo, avaluant possibles interaccions o sinergies entre ambdues fonts fenòliques.El enriquecimiento de aceite de oliva con sus propios fenoles se convierte en una estrategia interesante para aumentar y normalizar la ingesta diaria de hidroxitirosol sin aumentar el consumo calórico. Sin embargo, aceites con alto contenido fenólico tienen un sabor amargo que podría provocar rechazo entre los consumidores, y además sus altas dosis de hidroxitirosol podría tener una acción pro-oxidante. En esta tesis se planteó la estrategia de enriquecimiento de aceite de oliva no sólo con sus propios fenoles, sino con fenoles complementarios de hierbas aromáticas, concretamente tomillo, con la hipótesis de que no sólo podría proporcionar mejoras en la estabilidad del aceite y la aceptación de los consumidores, sino que podría aportar beneficios adicionales para la salud. Una vez desarrollado el aceite de oliva enriquecido se evaluó la biodisponibilidad de los fenoles mediante métodos in vitro e in vivo, evaluando posibles interacciones o sinergias entre ambas fuentes fenólicas.
The enrichment of olive oil with its own phenolic compounds becomes an interesting strategy to increase and standardize the daily intake of hydroxytyrosol without increasing the caloric intake. Concerning olive oils with high phenolic content, however, they have a bitter taste, which could promote a refusal among consumers, and contain high doses of hydroxytyrosol that could have a pro-oxidant action. In this context, the strategy of enriching olive oil not only with its own phenolics but also with complementary phenols from aromatic herbs was outlined in this thesis with the hypothesis that it could not only improve olive oil stability and consumers’ acceptation but also provide additional health benefits. In this thesis a phenol-enriched olive oil was developed using the aromatic herb of thyme, and the bioavailability of the phenolic compounds was assessed, evaluating possible interactions or synergies between both sources through in vitro and in vivo approaches.
4
Gralheira, Daniel José Rossa. "Tyrosinase-based phenol remediation." Master's thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/8951.
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Dissertation for the obtention of the Master Degree in BiotechnologyNanobiotechnology is an emerging area full of potentialities to explore and reshape instituted knowledge. In this work, the main goal was to design and test biological remediation systems (a total of three) taking advantage of nanotechnology features, as a step towards future progress of sense-and-shoot combined systems. This task involved the development of active bionanoconjugates (BNC) with two different tyrosinases (Agaricus bisporus - AbT, and Tricoderma reesei - TrT) to be implemented in three suggested phenol remediation systems. AuNP-MUA (gold nanoparticles capped with11-mercapto-1-undecanoic acid) 1:5000 colloid was shown to be stable up to 100 mM ionic strength (sodium cloride) and able to form active BNCs with AbT. TrT:AuNP ratio for BNC formation is recommended as 100, supported by zeta potential and agarose gel mobility experimental data which, in turn, atone with the proposed theoretical estimation. The incubation of 100 ppm phenol with BNC-MUA-AbT for 60 minutes achieved 50% substrate conversion (the efficiency of the systems were also investigated using ultravioletvisible spectrophotometry (UV-Vis) complemented by standard addition method and solid-phase microextraction - gas chromatography (SPME-GC)).
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Avci, Gulden. "Analysis Of Phenol Oxidation Products By Scytalidium Thermophilum Bifunctional Catalase/phenol Oxidase (catpo)." Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613770/index.pdf.
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This thesis was aimed to analyze phenol oxidation by the bifunctional catalase/phenol oxidase of the thermophilic fungus Scytalidium thermophilum. Several reactive oxygen species (ROS) are continuously produced in fungi under oxidative stress. Depending on the nature of the ROS species, some are highly toxic and are rapidly detoxified by various cellular enzymatic mechanisms, including the production of catalase. S. thermophilum produces a novel bifunctional catalase-phenol oxidase (CATPO) which is capable of oxidizing phenolics in the absence of hydrogen peroxide. Phenol oxidases convert phenolic compounds to quinones, which are then polymerized mainly by free- radical mediated reactions. In this study, 14 phenolic compounds were selected according to their different chemical structures and functional properties and were analyzed as substrates of CATPO. Among 14 phenolic compounds, only in catechol, chlorogenic acid, catechin and caffeic acid distinct oxidation products were observed by HPLC. The oxidation products of catechol, caffeic acid, chlorogenic acid and catechin were characterized by LC-ESI-MS. Dimer, trimer, tetramer and oligomer formations were detected. While the maximum conversion efficiency, at 1 hour of reaction, was observed with catechin, minimum conversion efficiency was attained by caffeic acid, under the specified conditions. The oxidation products observed after oxidation of catechol, chlorogenic acid, catechin and caffeic acid by CATPO was compared with the same phenolic compounds oxidation products oxidized by laccase and tyrosinase. CATPO was incapable of oxidizing tyrosinase and laccase-specific substrates tyrosine and ABTS respectively. However, the oxidizing spectrum of substrates indicates that the nature of phenol oxidation by CATPO appears to resemble mainly those of laccase.
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Spangenberg, Daniel. "Strukturelle und kinetische Untersuchungen an H-brückengebundenen ionischen Clustern des Phenols." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=962319643.
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Indurkar, Jayant R. "Selective para-funtionalization of phenol." Thesis, Nelson Mandela Metropolitan University, 2008. http://hdl.handle.net/10948/710.
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In previous work done in our laboratories, a method was discovered to produce phenolic mono-ethers from 4-hydroxyacetophenone and other 4-hydroxyketones by treating with ammonium peroxy-disulfate in an alcohol as a reaction solvent and in the presence of concentrated sulphuric acid or other strong protonic acids. Since this method of producing 4-alkoxyphenol ethers provides a very convenient way to modify hydroquinone and substituted hydroquinones to produce a variety of phenol mono-ethers, it was of interest to study the general scope of this reaction, including a more detailed investigation of the reaction mechanism. In previous studies, it was suggested that interaction between the aromatic pi-system of hydroquinone and the cyclohexa-2,5-diene structure of benzoquinone plays a significant role during the reaction. It was therefore of interest to investigate whether other compounds that are also capable of forming the cyclohexa-2,5-diene structure, will interact in a manner analogous to the hydroquinone/benzoquinone couple. Two specific compounds were selected for this purpose, namely 4-nitrosophenol and 4- (diphenylmethylene)cyclohexa-2,5-dien-1-one . The scope of etherification reactions of hydroquinone-benzoquinone or hydroquinone/benzoquinone like substrates such as 4-nitrosophenol and 4- (diphenylmethylene)cyclohexa-2,5-dien-1-one in the presence of acid catalyst and alcohols was investigated. These studies showed that hydroquinone, 4- nitrosophenol and 4-(diphenylmethylene)cyclohexa-2,5-dien-1-one successfully affords the phenolic ethers in good to excellent yield. For example, quantitative yield of 4-methoxyphenol could be obtained from a 1:1 mixture of hydroquinone and benzoquinone at the reflux temperature of methanol. In order to study the reaction mechanism, the cross-over reaction between tertbutylhydroquinone and benzoquinone (or hydroquinone and tertbutylbenzoquinone) was studied in detail. The results of these cross-over reactions were used to propose a mechanistic pathway that could explain the requirement for pi-interaction between the hydroquinone and benzoquinone molecules, the role of the acid catalyst, as well as the relative rates of hydroquinone and benzoquinone consumption during these reactions. The mechanism was also capable of explaining all the reaction products observed during these reactions. The work was then extended to reactions of 4-nitrosophenol and 4- (diphenylmethylene)cyclohexa-2,5-dien-1-one with methanol in the presence of either hydroquinone or benzoquinone. The results of these investigations strongly suggest the presence of similar interactions between these molecules that also influence the outcome of the reactions. The exploitation of pi-interactions between two molecules of these types investigated during this work opens an interesting field of chemistry. Clearly, the level of understanding developed during this work is only beginning to address this interesting field of chemistry and much work will need to be done to gain a fuller understanding of the chemistry involved as well as the potential synthetic value of these interactions.
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Korkmaz, Erdural Beril. "Morphine Biotransformation By Microbial Phenol Oxidases." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/3/12607014/index.pdf.
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ABSTRACT
MORPHINE BIOTRANSFORMATIONS BY
MICROBIAL PHENOL OXIDASES
Erdural Korkmaz, Beril
M.S., Department of Chemical Engineering
Supervisor: Prof. Dr. Ufuk Bakir
Co-Supervisor: Prof. Dr. Ayhan S. Demir
January 2006, 96 pages
The objective of this study is to perform morphine biotransformation by using phenol oxidases. Syctalidium thermophilum, Thermomyces lanuginosus and Phanerochaete chrysosporium cells and culture fluid were used as microbial intracellular and extracellular phenol oxidases. Besides the phenol oxidases produced in laboratory, commercial pure phenol oxidases, A. bisporus tyrosinase and laccase, T. versicolor laccase and horseradish peroxidase, were also used in the morphine biotransformation reactions. Morphine biotransformation to pseudo-morphine was achieved by using pure T. versicolor laccase, A.bisporous tyrosinase and laccase. Before utilization of phenol oxidases in morphine biotransformations, the time course of microbial phenol oxidase productions were followed. Maximum phenol oxidase activity of S. thermophilum were detected on the 5th day of cultivation as
0.17 U/ml and the 4th day of cultivation as 0.072 U/ml, respectively. On the other hand, maximum laccase activity of P. chrysosporium was detected on the 8th day of cultivation as 78.5 U/ml. Although phenol oxidases which were obtained from S. thermophilum or T. lanuginosus could not catalyze morphine biotransformation, phenol oxidases including a peroxidase of P. chrysosporium transformed morphine to pseudo-morphine and an unknown product.
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Han, Yiseon. "Arthromyces ramosus peroxidase catalyzed phenol removal." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0004/MQ34372.pdf.
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Seetharam, Gayathri B. "Degradation of phenol using immobilized tyrosinase." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0003/MQ41004.pdf.
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Sayyar, Mohammad H. "Direct oxidation of benzene to phenol." Thesis, Loughborough University, 2008. https://dspace.lboro.ac.uk/2134/15135.
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This thesis deals with two major process routes for the direct oxidation of benzene to phenol. The main objective of the first route was to understand the properties of the porous stainless steel (PSS) needed for support of a catalyst deposited onto its surface, to identify the morphologies of the Pd membrane deposited onto the PSS, to design a catalytic membrane reactor, to characterise membrane in terms of its permeability to hydrogen, and then to investigate hydroxylation of benzene using oxygen as an oxidant. It was observed, using Mo or zeolites as a second catalyst and the reactor design affect the productivity and selectivity towards phenol. This research has also shown the effects of the catalytic properties of iron zeolites with a focus on reactions involving the decomposition of nitrous oxide and direct oxidation of benzene to phenol using nitrous oxide as the oxidant. The main objective of this second route was to identify the active sites in the catalysts, and to a design catalyst based on the acquired knowledge. The methodology was to incorporate iron either at framework positions via hydrothermal synthesis of the zeolites followed by controlled migration to extra-framework positions, or directly at extra-framework positions via sublimation of FeCh or liquid ion-exchange. In this project, different catalysts were characterized and their catalytic activities compared. It was observed contaminants such as N-containing compounds, O2, CO, and water affected the catalytic properties and catalyst half-life. In this thesis, two different methods were used to improve productivity when using a PdlPSS membrane. First, changing design of the reactor, and second, using Mo as a second catalyst. It was observed that higher productivity was obtained when the reactor tube was packed with Fe/ZSM-5 and N20 using as the oxidant. From an economic point of view, using N20 in the presence of zeolite in a fixed-bed reactor is expected to offer more advantages than Pd membrane for oxidation of aromatic compounds.
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Scheffler, Thomas, Sascha Englich, and Michael Gehde. "Specific mold filling characteristics of highly filled phenolic injection molding compounds." Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-198644.
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Thermosets show excellent mechanical properties and chemical resistance (for most automotive fluids) even at high temperatures up to 300 °C. Furthermore they can be highly efficient processed by injection molding. So they should be particularly suited for e.g. under the bonnet applications. However, the reality shows that thermosets are, except fiber reinforced composites, heavily underrepresented in technical applications. E.g. thermosetting components only account 0,2 % to a vehicle’s weight. Therefore reasons can be found in limited knowledge, e.g. relating mold filling behavior.
The objective of the study is to analyze the influence of the mold filling behavior during injection molding of highly filled phenolic compounds on mechanical properties. Injection molding filling studies, mechanical testing and optical microscopy were done while varying mold geometry (injection gate and cavity height), mold temperature and injection rate during injection molding a highly filled phenolic compound. It was found that the mold filling behavior varies with altered injection molding parameters as well as the mold geometry. In consequence of this the mechanical properties change according to the resulting reinforcement orientation. The results can help to improve part and mold design for optimal load transmission.
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Westphal, Arnim. "Hochaufgelöste Laserfluoreszenzspektroskopie am Phenol(Methanol)1-Cluster." [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=96841415X.
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Roostaei, Nadia. "Removal of phenol from water by adsorption." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0001/MQ46605.pdf.
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Wang, Jinwu. "Cure kinetics of wood phenol-formaldehyde systems." Online access for everyone, 2007. http://www.dissertations.wsu.edu/Dissertations/Spring2007/j_wang_042207.pdf.
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Karlsson, Anna. "Anaerobic degradation of phenol and related aromatics /." Linköping : Tema, Univ, 2000. http://www.bibl.liu.se/liupubl/disp/disp2000/arts212s.htm.
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Sandhu, Amarjyoti. "Phyllosphere-mediated bacterial degradation of airborne phenol." [Ames, Iowa : Iowa State University], 2008.
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Scott, Elizabeth. "Phenol degradation by natural and recombinant microorganisms." Thesis, University of Liverpool, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369018.
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Wang, Feng Hu. "Stress relaxation in phenol formaldehyde bonded particleboards." Thesis, Cardiff Metropolitan University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314859.
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BODIBO, JEAN-PAULIN. "Alkylation et acylation du phenol sur zeolithes." Poitiers, 1991. http://www.theses.fr/1991POIT2336.
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L'objectif de ce travail est de montrer que des catalyseurs zeolithiques peuvent etre substitues aux solutions acide corrosives et dangereuses souvent utilisees pour la synthese d'aromatiques fonctionnels. Les reactions modeles choisies sont d'une part l'alkylation du phenol par le methanol, d'autre part le rearrangement de l'acetate de phenyle. Dans chacun des cas le schema reactionnel est etabli et les mecanismes discutes. Tous les produits de l'alkylation du phenol sur une zeolithe hy resultant de reactions d'o- et c-alkylation. L'anisole et les ortho- et para-cresols sont les produits primaires. Leur transformation conduit a des methylanisoles et dimethylphenols mais aussi a des produits permethyles qui ne desorbent pas du catalyseur et qui sont responsables de la desactivation. Les ordres de reaction sont en accord avec un mecanisme de type rideal, l'etape limitante etant la reaction entre le methanol adsorbe sur un site protonique et le phenol adsorbe physiquement dans les pores de la zeolithe. Sur la zeolithe hy, la transformation de l'acetate de phenyle en hydroxyacetophenones se produit par deux mecanismes, l'un intramoleculaire, l'autre bimoleculaire (dismutation) tandis que la zeolithe hzsm-5 elle se produit uniquement par dismutation. Les reactions secondaires dependent de la zeolithe: cyclisation de la 2-acetoxyacetophenone sur hy, formation de produits de condensation du cetene sur hzsm-5; ces produits secondaires sont responsables de la faible stabilite des zeolithes. Cette stabilite est nettement amelioree si l'acetate de phenyle est additionne d'eau ou s'il est remplace par un melange de phenol et d'acide acetique
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Scott, Brian Cameron. "Evaluation of Phenol Formaldehyde Resin Cure Rate." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/33222.
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Cure time is often the bottleneck of composite manufacturing processes, therefore it is important to understand the cure of todayâ s thermosetting adhesives. This research attempts to characterize the cure rate of two commercial phenol-formaldehyde adhesives. Two methods are used, parallel-plate rheometry and dielectric spectroscopy. Viscosity data from a parallel-plate rheometer may be used to track the advance of polymerization as a function of temperature. This data can then be used to optimize press conditions and reduce production times and costs.
The research will further examine resin cure through dielectric analysis; such a technique could monitor resin cure directly and in real-time press situations. Hot-pressing processes could conceivably no longer require a set press schedule; instead they would be individually set based on dielectric data for every press batch. Such a system may lead to a more efficient and uniform product because press times could be based on individual press cycles instead of entire product lines. A more likely scenario, however, is the use of in situ adhesive cure monitoring for troubleshooting or press schedule development.
This research characterized the cure of two phenol-formaldehyde resins using parallel-plate rheometry, fringe-field dielectric analysis, and parallel-plate dielectric analysis. The general shape of the storage modulus vs. time curve and the gel and vitrification points in a temperature ramp were found.
Both dielectric analysis techniques were able to characterize trends in the resin cure and detect points such as vitrification. The two techniques were also found to be comparable when the cure profiles of similar conditions were examined.
Master of Science
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Yang, Xing. "Organic Fillers in Phenol-Formaldehyde Wood Adhesives." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/64999.
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Veneer-based structural wood composites are typically manufactured using phenol-formaldehyde resols (PF) that are formulated with wheat flour extender and organic filler. Considering that this technology is several decades old, it is surprising to learn that many aspects of the formulation have not been the subject of detailed analysis and scientific publication. The effort described here is part of a university/industry research cooperation with a focus on how the organic fillers impact the properties of the formulated adhesives and adhesive bond performance. The fillers studied in this work are derived from walnut shell (Juglans regia), alder bark (Alnus rubra), and corn cob (furfural production) residue.
Alder bark and walnut shell exhibited chemical compositions that are typical for lignocellulosic materials, whereas corn cob residue was distinctly different owing to the high pressure steam digestion used in its preparation. Also, all fillers had low surface energies with dominant dispersive effects. Surface energy of corn cob residue was a little higher than alder bark and walnut shell, which were very similar.
All fillers reduced PF surface tension with effects greatest in alder bark and walnut shell. Surface tension reductions roughly correlated to the chemical compositions of the fillers, and probably resulted from the release of surface active compounds extracted from the fillers in the alkaline PF medium.
It was shown that viscoelastic network structures formed within the adhesive formulations as a function of shear history, filler type, and filler particle size. Relative to alder bark and walnut shell, the unique behavior of corn cob residue was discussed with respect to chemical composition.
Alder bark and walnut shell exhibited similar effects with a decrease of adhesive activation energy. However, corn cob reside caused much higher adhesive activation energy.
Alder bark exhibited significant particle size effects on fracture energy and bondline thickness, but no clear size effects on penetration. Regarding corn cob residue and walnut shell, particle size effects on fracture energy were statistically significant, but magnitude of the difference was rather small. Classified corn cob residue fillers all resulted in a similar bondline thickness (statistically no difference) that was different walnut shell.Ph. D.
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Ncanana, Sandile Welcome. "Biocatalytic studies of phenol oxidases producing antioxidants." Doctoral thesis, University of Cape Town, 2007. http://hdl.handle.net/11427/5429.
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Includes bibliographical references (leaves 172-198).In recent years there has been increasing interest in the production of oligomers and polymers of economic importance using biocatalysts; the application of enzymes in dimerisation or polymerisation processes can lead to the synthesis of unique compounds, with novel properties, that could not be easily achieved by conventional methods. Further, the application of biocatalysts in polymerization processes can be exploited in development of bioremediation systems, and there is a demand for new technologies that can be utilized in the removal of organic pollutants such as phenolics from contaminated environment. This study reports on the potential application of laccase, obtained from the white rot fungi Trametes pubescens, in the synthesis of organic compounds which are dimers or polymers, and in the development of bioprocesses of potential economic importance. The focus of this study is, particularly, on the effect of organic solvents and the structure of the substrates on the nature of products formed. The thesis also gives some insight into the relationship between the structure of laccase products and their biological (antioxidant and antimalarial) activity. The compounds tyrosol, hydroxytyrosol, 8-hydroxyquinoline, and totarol were selected as the model compounds for laccase reactions. Tyrosol was oxidised by laccase, yielding dimeric and polymeric compounds which were identified by LC-MS and IH-NMR. As a comparative study, hydroxytyrosol was also oxidised by laccase yielding dimeric, trimeric and polymeric compounds which were identified by LC-MS. Manipulation of this biocatalytic system resulted in development of an efficient process that allows for selectivity with respect to the products. A system was then developed whereby oxidation of hydroxytyrosol by laccase would selectively yield either dimers or oligomeric products. Thus, use of 50 % acetone in the reaction medium favoured the synthesis of dimeric products, and 20 % methanol resulted in the formation of a polymeric product. These results showed that hydroxytyrosol-laccase reactions were more readily controlled than tyrosol-laccase reactions, and this difference was attributed to structural configuration of these substrates.
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Phillips, David Gray 1949. "Acclimation of mixed cultures for phenol biodegradation." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276811.
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Experiments were conducted to examine the cause of lag-phase growth during phenol degradation by mixed microbial cultures that had been acclimated to one of four substrates. Four aerated Imhoff cones were inoculated with wastewater sludge and fed one of four substrates: acetate, egg albumin, vegetable oil, or phenol. Inocula from these cones were injected into batch reactors containing phenol. Time-dependent growth was measured by two methods: most probable number (MPN) and epifluorescence microscopy (EM). The MPN technique was used to distinguish two cell concentrations: total cells and a phenol-degrading community within the total; EM was also used to count total cells. The results indicated that a lag in phenol utilization for all cultures, except the phenol-acclimated cultures, was a result of growth of a phenol-degrading subpopulation, and not due to enzyme induction of the existing population. Similar experiments were conducted using 2,4-dichlorophenol (2,4-DCP), which resulted in no growth and no degradation of 2,4-DCP.
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Vogel, Frédéric. "Nassoxidation von Phenol mit Sauerstoff bei milden Bedingungen /." [S.l.] : [s.n.], 1997. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=12267.
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Castro, Cevallos Ursula Isabel. "Phenol oxidation catalysed by polymer-supported metal complexes." Doctoral thesis, Universitat Rovira i Virgili, 2009. http://hdl.handle.net/10803/8577.
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Focussing on the treatment of industrial effluents with high content of organic compounds, the advanced oxidation processes (AOPs) develop technologies such as the catalytic wet peroxide oxidation of organic compounds (CWPO). The improvement of this process is based on the variation either of the catalyst or the oxidant source. The present research work proposes to get advantage of the catalytic activity of homogeneous catalysts, avoiding the metal contamination of the reaction media by the heterogenization of Cu(II) ions over polymeric matrices, to finally use them as catalysts in the CWPO of phenol. From the group of synthesised catalysts, it was identified two suitable catalysts: Cu(II) adsorbed onto poly(4-vinylpyridine) with 2% of cross-linking and Cu(II) loaded in poly (DVB-co-VBC) functionalised with imino diacetic acid. Both catalysts demonstrated high catalytic activity without Cu(II) release, concluding that heterogenization of catalysts for the CWPO is an ascertained decision to promote phenol degradation.Entre los tratamiento de efluentes industriales con alto contenido de material orgánico, se encuentran los procesos de oxidación avanzada (AOPs) que desarrollan tecnologías como la oxidación húmedo catalítica con peroxido de hidrógeno de compuestos orgánicos (CWPO). El mejoramiento de éste proceso está basado en la variación tanto del catalizador como de la fuente oxidante. El presente trabajo de investigación propone aprovechar la actividad catalítica de catalizadores homogéneos, evitando la contaminación por metal del efluente mediante la heterogeneización de iones de Cu(II) sobre matrices poliméricas, para luego ser usados como catalizadores en la CWPO del fenol. Del grupo de catalizadores sintetizados, se identificaron dos catalizadores: Cu(II) adsorbido sobre poly(4-vinylpyridine) con 2% de entrecruzamiento y Cu(II) soportado en poli (DVB-co-VBC) funcionalizado con ácido aminodiacetico. Ambos catalizadores demostraron alta actividad catalítica sin liberación de Cu(II), concluyendo que la heterogeneización de catalizadores homogéneos para la CWPO es una decisión acertada cuando se desea promover la degradación del fenol.
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Kallos, Alexander. "Characterization of cure of phenol formaldehyde foaming resin." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63800.
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Chen, Tong, and 陳彤. "Anaerobic treatment of benzoate- and phenol- containing wastewaters." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B31212918.
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Varnavas, Christalla Zenos. "Synthetic studies directed towards sesquiterpene-phenol natural products." Thesis, University of Salford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366319.
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Sylvestre, Isabelle. "Copper complexes of new biologically relevant phenol ligands." Thesis, University of Leeds, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.410895.
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Chen, Tong. "Anaerobic treatment of benzoate- and phenol- containing wastewaters /." Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B17590607.
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Rautenbach, Daniel. "The development of an electrochemical process for the production of para-substituted di-hydroxy benzenes." Thesis, Nelson Mandela Metropolitan University, 2005. http://hdl.handle.net/10948/159.
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The project was concerned with the investigation of the electrochemical oxidation of various phenols, and to develop a viable reaction system for the production of the respective hydroquinones. Current production routes utilizing phenol as starting material have the limitations of using large amounts of acids, having to be stopped at low conversions and producing a mixture of the hydroquinones and catechols. Of the possible routes to the respective hydroquinones from the various phenols, the electrochemical oxidation of these phenols offers commercial and environmental advantages and hence formed the theme of the investigation. The synthetic possibilities proved to be more prevalent in a system when the electrochemical oxidation of these phenols was performed in an aqueous medium utilizing an organic co-solvent. Results obtained during this investigation made it possible to make certain predications about the mechanism taking place. This was found to depend on the anode material used for the oxidation. The results showed that the process developed for the electrochemical oxidation of these phenols, yields mainly the para-isomers of the respective hydroquinones and benzoquinones in good yields and selectivities, with fair current efficiencies and good mass balances at high conversions. For example: * Phenol (batch) 8 F: 345% current efficiency, 70% hydroquinone, 6% catechol, 9% benzoquinone, 9% phenol and 94 mass balance. * 2-Tert-butylphenol (flow) 10 F: 37% current efficiency, 65% hydroquinone, 33% benzoquinone, 2% phenol and 100% mass balance. * 2,6-Di-tert-butylphenol (flow) 11 F: 23% current efficiency, 92 % hydroquinone, 6% benzoquinone, 1% phenol and 99% mass balance. The developed electrochemical oxidation system offers the following advantages over previous and current methods: simplified isolation and extraction procedures, smaller amounts of acid usage, reasonably selective synthesis of the para-isomer and a less corrosive system all at high conversions.
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Pongoma, Basanda. "The investigation of alternative processes for the oxidation of phenol." Thesis, Nelson Mandela Metropolitan University, 2010. http://hdl.handle.net/10948/1479.
Full textAbstract:
The electrochemical oxidation of phenol can be considered as an important process for either producing value added products such as hydroquinone and catechol or for the removal of the phenol from waste water streams to form carbon dioxide. This process had been extensively studied with the main focus on type of anode material used. Even though the anode material could be made from a range of materials, this study focused on using PbO2 as anode material that was made by using Pb-acid battery principles in designing a microporous electrode. In this study, the focus was on using lead dioxide as an anode material that was made by using the formation principles used in the manufacturing of Pb-acid batteries. This allowed for the construction of an electrochemical flow-through micro-porous reactor that contained PbO2 as the anode and Pb as the cathode, allowing for a solution containing phenol to flow through the cell continuously. By applying a suitable potential across the cell, the almost complete oxidation of phenol would occur to form benzoquinone, which was followed by the sequential reduction to other products such as hydroquinone and catechol. The system was shown to be made up of tightly packed micro-porous material that had a very high surface area-to-volume ratio. The study showed that between 80 to 90 percent successful conversion of a 50 mM solution of phenol could be achieved by optimizing the continuous flow process of up to 500 minutes. The main reaction product from this process was hydroquinone, of up to 60 percent with a number of the minor products of which not all could be identified. In order to utilize the characteristics of this reactor system, its design and reaction conditions such as applied potential, phenol concentration, co-solvent concentration and support electrolyte concentration were investigated to optimize the convection of phenol and the yield of hydroquinone.
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Lloyd-George, Ian. "The conversion of ammonia, phenol and pyruvate into tyrosine by the use of the tyrosine phenol-lyase activity of microencapsulated Erwinia Herbicola." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41200.
Full textAbstract:
The tyrosine phenol-lyase (TPL)-E.C. 4.1.99.2-activity of free and alginate-polylysine-alginate microencapsulated whole cells of Erwinia herbicola, was used to convert ammonia, pyruvate and phenol or catechol into L-tyrosine of dihydroxyphenyl-L-alanine (L-dopa). This conversion could serve as the basis of a novel system for the removal of toxic ammonia and phenol from the blood during liver failure.It was found that there were endogenous modifiers in the whole cell TPL system, hence the kinetic parameters vary with the amount of cells in the system. However typically the apparent $ rm K sb{M}$ for tyrosine varied from 0.2 mM to 0.28 mM, while that of phenol was 0.5 mM. Whole cell TPL can display kinetics of great complexity, suggesting that the enzyme is likely to be a tetramer.
The effect of process variables on the relative strength of alginate-PLL-alginate microcapsules can be conveniently assessed by entrapping blue dextran (Mwt 2.0 $ times$ 10$ sp6$) within the microcapsules and then agitating them within a rotary shaker.
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Kaptan, Yelda. "Utilization Of Scytalidium Thermophilum Phenol Oxidase In Bioorganic Synthesis." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/2/12605353/index.pdf.
Full textAbstract:
ABSTRACT
UTILIZATION OF SCYTALIDIUM THERMOPHILUM PHENOL OXIDASE IN BIOORGANIC SYNTHESES
Kaptan, Yelda
M.S., Department of Biotechnology
Supervisor: Prof. Dr. Zümrü
t B. Ö
gel Co-supervisor: Prof Dr. Ufuk Bakir September 2004, 90 pages In this study, the ultimate aim was to utilize phenol oxidases of Scytalidium thermophilum in bioorganic syntheses. For this purpose, studies were conducted towards enhancing the production of phenol oxidases by Scytalidium thermophilum, developing a suitable method for laccase activity assays, analyzing the effects of organic solvents on phenol oxidase activity and analysis of the biotransformation of a number of organic substrates by phenol oxidases of Scytalidium thermophilum. In order to enhance the production of phenol oxidases, induction experiments were carried out with gallic acid, syringaldazine and chlorogenic acid. Gallic acid was found as the most effective inducer for phenol oxidase production. Inductive effect of edible mushroom Agaricus bisporus was also assayed, however, the phenolic compounds released by mushroom did not represent any induction for phenol oxidase activity of Scytalidium thermophilum. Different substrates were tested and catechol was determined as the most suitable substrate rather than syringaldazine and ABTS. Molar extinction coefficient (e) of catechol was calculated as 3450 M-1 cm-1 and 3700 M-1 cm-1 by using &ldquo
substrate blank&rdquo
and &ldquo
enzyme blank&rdquo
respectively at 420 nm. Kinetic parameters, Km and Vmax for the enzymatic reactions in which catechol was used as substrate were calculated as 52.03 mM and 0.253 U/ml respectively from Lineweaver-Burk plot and as 41.25 mM and 0.2055 U/ml from Hanes-Woolf plot. Effect of some organic solvents on phenol oxidases of Scytalidium thermophilum was assayed and DMSO was found as an appropriate solvent for the organic substrates. Phenol oxidase containing culture supernatant could oxidize benzoin, hydrobenzoin and benzoyl benzoin.
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Bagherifam, Shahla. "Thermal Characterization Of Phenol And Bisphenol-a Based Polybenzoxazines." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610409/index.pdf.
Full textAbstract:
Although, several researches on synthesis and characterization of benzoxazines and
polybenzoxazines have appeared in the literature, detailed studies on thermal
characterization are still limited. In this study, polymerization and thermal
degradation mechanisms of benzoxazines were investigated via direct pyrolysis mass
spectrometry. Benzoxazine monomers prepared by reactions of phenol or bisphenol-
A with aniline or methyl amine were analyzed to investigate the effects of the
structures of phenyl and amine groups on both polymerization and thermal
degradation behaviours.
It has been proposed in the literature that polymerization of benzoxazines occurs by
ring opening polymerization of oxazine ringcleavage of O-CH2 bond of the oxazine ring and attack of n-CH2 group to phenol or bisphenol-A ring. However, the direct pyrolysis mass spectrometry analyses of polymerization and thermal degradation of benzoxazines pointed out that after the cleavage of O-CH2 bond of the oxazine ring, polymerization proceeded through opposing pathways. Strong evidences confirming coupling of (CH3)NCH2 or (C6H5)NCH2 groups yielding dimers involving diamine linkages were detected. Polymerization of the dimer by the reactions with the corresponding monomers was proposed. In case of benzoxazines based on bisphenol-A, the results indicated polymerization of the dimer ii by coupling of both of the oxazine rings. On the other hand, polymerization of the dimer through the ethylene units (vinyl polymerization) in case of benzoxazine monomer based on phenol and methyl amine was also noted. For polybenzoxazines based on aniline another polymerization pathway involved attack of radicals generated by cleavage of the oxazine ring to aniline ring. Multi-step thermal decomposition was observed for all the polybenzoxazines under investigation confirming the presence of units with different structures and stabilities.
37
Villalobos, Tinoco Daniel Alberto. "Advanced studies on phenol removal using Arthromyces ramosus peroxidase." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0008/MQ59895.pdf.
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Neidlinger, Andreas [Verfasser]. "Ferrocene-phenol conjugates – secondary structures and reactivity / Andreas Neidlinger." Mainz : Universitätsbibliothek Mainz, 2017. http://d-nb.info/1126763152/34.
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Soegiaman, Selvia Kurniawati. "Kinetics of the laccase-catalyzed oxidation of aqueous phenol." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103010.
Full textAbstract:
Laccase (E.C 1.10.3.2) catalyzes the oxidation of aromatic substrates with the simultaneous reduction of molecular oxygen to water. It has significant potential for use in many applications due to its high reaction rates, broad substrate-specificity, and use of oxygen as an inexpensive co-factor. The objective of this research was to investigate the ability of laccase from Trametes versicolor to catalyze oxidation reactions under a variety of reaction conditions and to model the kinetics of these transformations. Phenol was selected as a model substrate.Laccase was very stable when incubated at temperatures less than 30°C and pHs between 6 and 7. The optimum pH for phenol transformation was 6, but when present in sufficient quantities, laccase was able to significantly transform phenol at pHs from 4 to 7 and temperatures from 10 to 60°C. Laccase stability was negatively impacted by the presence of four common redox mediators. Of these, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) and 2,2',6,6'-tetramethylpiperidine-N-oxyl (TEMPO) significantly enhanced phenol transformation but large quantities were required, which may limit the feasibility of the use of these mediators in many applications.
A series of kinetic models was developed in order to achieve a better understanding of the mechanisms and kinetics of laccase-catalyzed reactions and to eventually assist in the choice and design of suitable reactor systems. These models were designed to predict the transient oxygen and phenol concentrations during laccasecatalyzed reactions at pH 6 and 25°C. Over the course of developing and validating these models, it was observed that: (1) the rate-limiting step in the catalytic reactions is the reaction between the oxidized form of laccase and phenol; (2) the stoichiometric ratio, which is defined as the molar ratio of phenol transformed to oxygen consumed in the catalytic reaction, was found to increase with phenol concentration in the reaction mixture from a theoretical lower limit of 1 and to approach a theoretical upper limit of 4; and (3) laccase inactivation occurs over the course of the reaction and was found to be dependent on the rate of substrate transformation.
Ultimately, these findings were incorporated into a comprehensive kinetic model to predict transient species concentrations in an open-system environment where the degree of substrate transformation was not limited by oxygen availability. The model accounts for enzyme kinetics, oxygen mass-transfer, variable reaction stoichiometry, and inactivation related to reaction products. Excellent agreement was observed between measured and modeled phenol and oxygen concentrations for a wide range of initial phenol concentrations and enzyme activities. Simplified models were also developed by incorporating an assumption, referred to as the pseudo-steady-state assumption, that at any instant during the reaction, the enzyme achieves an approximate steady-state distribution of its various forms around the catalytic cycle. The pseudo-steady-state assumption had the advantage of reducing the complexity of model equations without sacrificing their predictive abilities and allowing enzyme quantities to be expressed in activity units instead of molar concentrations.
40
Fürtges, Leon [Verfasser], and Michael [Akademischer Betreuer] Müller. "Oxidative phenol coupling in ascomycetes: regioselectivity of coupling enzymes." Freiburg : Universität, 2018. http://d-nb.info/1163945870/34.
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Al-Hazmi, Naeem. "One step hydroxylation of benzene to phenol using N2O." Thesis, Loughborough University, 2011. https://dspace.lboro.ac.uk/2134/8299.
Full textAbstract:
There is an increasing commercial interest in finding alternative ways to produce phenol that overcome the disadvantages of the current cumene process used to synthesize phenol. The drivers for the change are both economic and environmental. A direct oxidation route for producing phenol from benzene is based on using N2O as an oxidizing agent in the gas phase in the presence of modified Fe-ZSM5 zeolite. One of the main objectives was to examine the effect of different Si/Al ratios, temperatures and iron content on the selective conversion of benzene to phenol with a desire to achieve high selectivity and minimise catalyst deactivation. Also one of the research objectives was to identify the active sites in the catalyst and design the catalyst which is able to delay coke formation. The methodology was to incorporate iron directly at extra-framework positions via liquid ion-exchange. In this project, a series of selective Fe-ZSM5 catalysts with different Si/Al ratios have been prepared and evaluated for selective formation of phenol. The catalyst samples were characterized (by Atomic Absorption Spectroscopy (AAS), Malvern mastersizer and Nitrogen adsorption using N2 at 77 K via Micromeritics to determine the elemental composition, average particle size, BET surface area and pore size distribution) and their catalytic activities compared. A quantitative comparison between the number of active sites using isopropylamine decomposition method shows that active sites increase as the Si/Al ratio increased and also as the iron content increased. (Continues...).
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Chanton, Patrick. "Calibration of phenol oxidase measurement in acidic wetland environments." Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/52329.
Full textAbstract:
Phenol oxidases mediate the degradation of recalcitrant compounds, polyphenolics, in wetland soils and are considered to play a key role in the microbial carbon cycle of peatlands which predominate in boreal biomes. In order to validate a method for quantification of oxidative enzyme activity in acidic wetland environments, the relationship between pH and substrate oxidation was studied using the standard enzyme tyrosinase and in soils collected from six freshwater wetlands including three marshes in north Florida and peatlands of northern Minnesota. Phenol oxidase (PO) activity was quantified with two commonly used assay substrates, ABTS (2,2'-azino-bis(3-ethylobenzthiazoline-6-sulfonic acid) and L-DOPA (L-3,4-dihydroxyphenylalanine), across a pH range of 4 to 7 which matched the in situ pH range of the studied wetlands. The PO assay is sensitive and activity could be detected with either substrate across a pH range of 4 to 7. However, with the standard enzyme tyrosinase, it was shown that a large change or threshold in oxidation rates occurred at pH 5. At pH < 5, L-DOPA oxidation rates were greatly diminished and ABTS oxidation was at a maximum. Above pH 5, ABTS oxidation occurred at much slower rates and L-DOPA oxidation was at a maximum. The pH response of PO activity in wetland soils corroborated observations made with tyrosinase. Thus, ABTS is recommended to be an effective substrate for the quantification of PO activity at an in situ pH of < 5, while L-DOPA is recommended at an in situ pH of > 5. In soils collected from a northern Minnesota peatland, assays conducted at an in situ pH of 4 showed one to two orders of magnitude higher rates of PO activity in solid phase peat in comparison to porewater, indicating that the majority of PO activity is associated with the peat. At three Minnesota peatland sites, PO activity was shown to attenuate with depth in agreement with the activities of other enzymes and with rates of peat decomposition.
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Huang, Tung-Li. "The removal of ammonia and phenol by hydrophobic catalyst." Thesis, University of Sheffield, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310652.
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Scheffler, Thomas. "Werkstoffeinflüsse auf den Spritzgussprozess von hochgefüllten Phenol-Formaldehydharz-Formmassen." Universitätsverlag Chemnitz, 2018. https://monarch.qucosa.de/id/qucosa%3A32200.
Full textAbstract:
Im Rahmen der vorliegenden Arbeit wurden verschiedene duroplastische Formmassen laboranalytisch hinsichtlich der rheologischen und thermischen Eigenschaften untersucht. Es wurde u.a. gezielt die absolute Materialfeuchte gesteigert, um den Einfluss dieser auf das Fließ Härtungsverhalten zu charakterisieren. Anschließend wurden die Materialien auf einer hochinstrumentierten Spritzgussmaschine mit einem Fließspiralenwerkzeug untersucht. Dabei konnte ein direkter Zusammenhang zwischen dem Rückfluss und dem Plastifizierdrehmoment in Abhängigkeit der Materialfeuchte und der Prozessparameter detektiert werden . Des Weiteren wurden über die Differenzdruckmessung im Fließspiralenwerkzeug die scheinbaren Viskositäten über den Fließweg ermittelt. Hierbei konnten unterschiedliche Aufschmelzeffekte über die Fließweglänge in Abhängigke it der duroplastischen Formmasse, der absoluten Materialfeuchte und der Prozessparameter detektiert werden . Durch Schererwärmung konnte die Formmassentemperatur teilweise die Werkzeugtemperatur übersteigen. Hinsichtlich der mechanischen Eigenschaften (Schlagzähigkeit, Biegefestigkeit) konnten keine signifikanten Einflussgrößen detektiert werden. Hinsichtlich des Tg konnten systematischen Unterschiede detektiert und begründet werden. Die beste Möglichkeit zur Ermittlung des Tg lieferte die TMA. Die thermischen Glasübergänge korrelieren mit den in der DSC ermittelten Aushärtegraden , wobei mit steigender Materialfeuchte ein geringer Aushärtegrad detektiert wird.Within this paper, the rheologieal and thermie eharaeteristies of different thermosetting molding eompounds were investigated using lab analysis methods. Among others, the absolute moisture eontent was inereased purposefully to investigate its influenee on the flow-euring behavior. Subsequently, the materials were analyzed using a highly instrumented injeetion-molding maehine and a flow spiral tool. A direet link between the baekflow and the plastifieation torque dependent on the moisture eontent and proeess parameters was deteeted . Furthermore, a measurement of the differential pressure was eondueted within the flow spiral to deteet the apparent viseosity over the flow path. Within this proeess, different melting effeets over the flow eurve length depending on the molding eompound, the absolute moisture eontent and proeess parameters were deteeted. The shear heating lead to a material temperature inerease of the molding eompound, whieh was partly higher than the tool temperature . Coneerning the meehanieal eharaeteristies (impaet strength, flexural strength), no signifieant influeneing faetors eould be deteeted. In eontrast, systematie differenees of the glass transition temperature were deteeted and their eause eould be explained. The best way to determine the glass transition is the TMA. The glass transition temperatures eorrelate with the degree of eure determined with the DSC, whereas an inereasing moisture eontent is assoeiated with a lower degree of eure.
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Laborie, Marie-Pierre Genevieve. "Investigation of the Wood/Phenol-Formaldehyde Adhesive Interphase Morphology." Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/26411.
Full textAbstract:
This work addresses the morphology of the wood/ Phenol-Formaldehyde (PF) adhesive interphase using yellow-poplar. In this case, morphology refers to the scale or dimension of adhesive penetration into wood. The objective is to develop methods for revealing ever smaller levels of wood/resin morphology. Dynamic techniques that are commonly utilized in polymer blend studies are investigated as potential methods for probing the wood/ adhesive interphase morphology. These are Dynamic Mechanical Analysis (DMA) and solid state NMR using CP/MAS. PF resin molecular weight is manipulated to promote or inhibit resin penetration in wood, using a very low or a very high molecular weight PF resin.
With DMA, the influence of PF resin on wood softening is investigated. It is first demonstrated that the cooperativity analysis according to the Ngai coupling model of relaxation successfully applies to the in-situ lignin glass transition of yellow-poplar and spruce woods. No significant difference in intermolecular coupling is detected between the two woods.
It is then demonstrated that combining simple DMA measurements with the cooperativity analysis yields ample sensitivity to the interphase morphology. From simple DMA temperature scans, a low molecular weight PF (PF-Low) does not influence lignin glass transition temperature. However, the Ngai coupling model of relaxation indicates that intermolecular coupling is enhanced with the low molecular weight PF. This behavior is ascribed to the low molecular weight PF penetrating lignin on a nanometer scale and polymerizing in-situ.
On the other hand, a high molecular weight resin with a broad distribution of olecular weights (PF-High) lowers lignin glass transition temperature dramatically. This plasticizing effect is ascribed to a small fraction of the PF resin being low enough in molecular weight to penetrate lignin on a nanoscale, but being too dispersed for forming a crosslinked network.
With CP/MAS NMR, intermolecular cross-polarization experiments are found unsuitable to probe the angstrom scale morphology of the wood adhesive interphase. However, observing the influence of the PF resins on the spin lattice relaxation time in the rotating frame, HT1r, and the cross-polarization time (TCH) is useful for probing the interphase morphology. None of the resins significantly affects the cross-polarization time, suggesting that angstrom scale penetration does not occur with a low nor a high molecular weight PF resin. However, the low molecular weight PF substantially modifies wood polymer HT1r, indicating that the nanometer scale environment of wood polymers is altered. On the other hand, the high molecular weight PF resin has no effect on wood HT1r. On average, the high molecular weight PF does not penetrate wood on a nanometer scale. Interestingly, the low molecular weight PF resin disrupts the spin coupling that is typical among wood components. Spin coupling between wood components is insensitive to the high molecular weight PF. Finally, it is noteworthy that the two PF resins have significantly different T1r 's in-situ. The low molecular weight resin T1r lies within the range of wood relaxations, suggesting some degree of spin coupling. On the other hand, the T1r of the high molecular weight PF appears outside the range of wood relaxations. Spin coupling between the high molecular weight resin and wood components is therefore inefficient.
The CP/MAS NMR and DMA studies converge to identify nanometer scale penetration of the low molecular weight PF in wood. On the other hand, the high molecular weight PF resin forms separate domains from wood, although a very small fraction of the PF-High is able to penetrate wood polymers on a nanoscale.Ph. D.
46
Abutaleb, Ahmed Alhassan. "Conversion of Phenol to Cyclohexanone Using Nanofiber Supported Catalysts." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1444144338.
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47
Gohil, Amit. "Bacterial oxidoreductase-catalysed metabolism of phenol and aniline substrates." Thesis, Queen's University Belfast, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.706684.
Full textAbstract:
Chapter 1. Provides an Introduction to dioxygenases, their Involvement In aromatic degradation ant formation of chiral c/s-dlols. The toluene dioxygenase (TOO, mechanism of action, amino acids In the active site and their blocatalytlc activity towards phenolic metabolites are Introduced. Application: of these chiral c/s-dlol metabolites obtained by TDO-catalysed oxidations are exemplified. Chapter 2. Whole cell biotransformations of meta-methoxyphenol using the constitutive mutanl Pseudomonas putlda UV4 strain expressing TOO and Inducer recombinant Escherichia coll (pCL-4T strain exclusively expressing TDO was conducted. Scale-up blotransformatlon of meta methoxyphenol was also discussed. The metabolites were Isolated and characterised fully by uslnf X-ray crystallography, NMR spectroscopy, GC- and LC- mass spectrometry. Add- and base chemocatalysed reactions of the major cydohexenone c/s-dlol metabolites were also studied. Chapter 3. Similar methods were used for the blotransformatlon of ort/io-methoxyphenol (gualacol, using P. putlda UV4 and Escherichia coll (pCL-4T) strains, where the metabolites were Isolated and characterised fully. In-depth stability, conformational and configurational studies were conducted on the isolated metabolites. Results for blotransformatlon of para-methoxyphenol were also presented. Biosynthetic pathways were proposed and discussed, for the formation of novel chiral metabolites derived from phenolic substrates. Chapter 4. Having established the structure and stereochemistry of metabolites derived from methoxyphenols (Chapter 2 and 3), studies of whole cell blotransformatlons with a series of substituted anilines and their corresponding phenol counterparts using P. putlda UV4 and E.coll (pCL-4T) whole cells were described. Blotransformatlon of a series of other substituted phenols, catechols and hydroquinones using both these strains were also attempted. Detection and confirmation of the presence of TDO-catalysed metabolites was examined by a combination of GC-MS and LC-MS analytical methods. Chapter 5. Contains prellmarary computational docking studies and elaborates on the future prospects of dioxygenase-catalysed studies. Chapter 6. Methodology, experimental and computational docking results.
48
Molva, Murat Polat Hürriyet. "Removal of phenol from industrial wastewaters using lignitic coals/." [s.l.]: [s.n.], 2004. http://library.iyte.edu.tr/tezler/master/cevremuh/T000458.pdf.
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Ekstrand, Johan. "Enhancement of Phenol Formaldehyde Adhesive with Crystalline Nano Cellulose." Thesis, Linnéuniversitetet, Institutionen för skog och träteknik (SOT), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-85468.
Full textAbstract:
Abstract The wood industries to this day use almost exclusively petroleum derived adhesives that are based mainly on the reaction of formaldehyde with urea, melamine or phenol. These adhesives have low cost and good adjustable properties which makes it hard for bio-based alternatives to compete. Phenol formaldehyde (PF), as an example of a synthetic adhesive, has been in use for over 100 years. In some parts of the world, legislation around formaldehyde is changing, and there is an increasingly voluntary awareness about the toxicity and unsustainability of formaldehyde. Industries realize that raw materials from oil is unstainable. The latter is currently a driving factor behind research on alternatives to amino based adhesives. Also, consumer interest in healthy and sustainable products, such as emitting less formaldehyde indoors, increases the need for bio based adhesives. Cellulose contained in plant cell walls is a renewable, abundant and nontoxic resource. During the last decades, many innovations have been achieved around cellulose and this trend does not seem to be slowing down. Cellulose shows excellent mechanical properties, high strength, high elastic modulus as well as having a low density. Research about cellulose reinforced adhesives has been increased the last years. This thesis studied the enhancement of phenol formaldehyde adhesive with Crystalline Nano Cellulose (CNC) at 5wt% and 10wt% loading levels for producing plywood boards. Indecisive results when using CNC higher than 3wt%, especially with PF resin, have been reported by other authors. In this thesis, European standards were applied. EN 314 was applied to test the panels shear strength. Three (3) treatment classes were selected, indoor room condition as well as pre-treatments 5.1.1 and 5.1.3. Other properties measured were modulus of elasticity, thickness swelling, formaldehyde emissions. Results showed a shear strength increase for all pre-treatment classes. 10wt% CNC mixture with phenol formaldehyde in water bath, pre-treatment (5.1.1) for 24h showed the highest increase in shear strength (+73,9%). The 10 wt% CNC mixture panels also showed the highest wood fibre failure of all panel types produced. A decrease in MOE has been observed with 10 wt% CNC compared to the 5 wt% CNC panels. Formaldehyde emissions tests were inconclusive, but since less PF was used, there was a general reduction in emissions. The 5 wt% CNC panels were superior in terms of modulus of elasticity and swelling and also showed improved shear strength.
50
Akude, Angela M. "Production of Phenol-formaldehyde Adhesives from Catalytic Pyrolysis Oil." DigitalCommons@USU, 2017. https://digitalcommons.usu.edu/etd/5612.
Full textAbstract:
Phenol-formaldehyde adhesives are important adhesives known to have superior water resistance capacity and high mechanical strength when utilized in wood-based applications. Due to unsustainability and environmental issues associated with the use of fossil fuels, there is an urgent need to look for alternative raw materials, which are renewable in nature. Pinyon-juniper biomass has been found to be a suitable replacement for petroleum-based phenol because it is renewable, abundant, and readily available.
In this thesis, bio-oil produced from the pyrolysis of pinyon-juniper biomass using red mud alumina catalyst was used to produce wood adhesives. The characterization of pinyon-juniper bio-oil showed the presence of phenolics, aromatic hydrocarbons, aliphatic hydrocarbons, carboxylic acids, ethers, ketones, aldehydes, and aliphatic alcohols.
Resol synthesis parameters such as formaldehyde-to-phenol molar ratio (1.8 and 2), catalyst loading (0.25, 0.63, and 1.25 g of NaOH), reaction time (60 minutes), and reaction temperature (95°C), were investigated in the production of pinyon-juniper adhesives. Based on the results obtained, the extent of phenol substitution with pinyon-juniper bio-oil was dependent on the amount catalyst used during the synthesis process. The maximum phenol substitution of 80% was achieved using a catalyst loading of 1.25 g of NaOH while the minimum phenol substitution of 50% was obtained at a catalyst loading of 0.25 g of NaOH.
Dry shear strength (8.99 to 12.73 MPa) and wet shear strength of (5.16 to 7.36 MPa) for both pure phenol-formaldehyde resols and pinyon-juniper substituted resols were comparable and exceeded the minimum requirement of 0.66 MPa for plywood. Finally, the chemical structure of pure phenol-formaldehyde resols showed the presence of more phenolic OH groups compared to pinyon-juniper substituted resols. This observation was corroborated by the higher concentration of free phenol in pure phenol-formaldehyde adhesives compared to pinyon-juniper substituted resols.