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Silva, Pedro Henrique Fernandes. "Fracionamento da biomassa lignocelulósica pelo processo organosolv." reponame:Repositório Institucional da UnB, 2017. http://repositorio.unb.br/handle/10482/23561.
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Dissertação (mestrado)—Universidade de Brasília, Instituto de Química, Programa de Pós-Graduação em Tecnologias Química e Biológica, 2017.Submitted by Raquel Almeida (raquel.df13@gmail.com) on 2017-05-12T17:31:19Z No. of bitstreams: 1 2017_PedroHenriqueFernandesSilva.pdf: 2269694 bytes, checksum: 5d996a917c19246d3b909b397afb4b5d (MD5)
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A biomassa tem ganhado destaque como matéria-prima renovável para obtenção de produtos químicos e energia, frente a uma competitiva indústria baseada em fontes fósseis. No Brasil, a biomassa florestal é largamente cultivada, seja na construção civil e fabricação de móveis, ou na produção de energia e na produção do papel. O eucalipto é a biomassa florestal de maior relevância em termos de cultivo no Brasil (38,1 m³/ha/ano no ano de 2015) e no mundo. Nas últimas décadas, têm-se buscado a desconstrução da biomassa lignocelulósica, como a madeira, em seus polímeros constituintes, a celulose, a hemicelulose e a lignina, de forma que cada uma possa ser processada de forma a gerar produtos de maior valor agregado. Neste contexto temos o processo organosolv, que é um pré-tratamento da biomassa lignocelulósica com a mistura de solventes orgânicos e água em elevadas temperaturas. Além de fracionar a biomassa, é possível se obter a partir do processo organosolv, componentes com elevado grau de pureza e mais reativos para futuras aplicações. O presente trabalho teve como objetivo estudar o efeito da temperatura (avaliada entre 180 °C e 220 °C) e relação etanol/água (avaliada entre 30% e 70% v/v) no processo organosolv aplicados a amostras de Eucalyptus grandis, sendo observado quanto de cada um dos polímeros foi removido da amostra sólida inicial. Os experimentos foram realizados segundo um planejamento experimental fatorial 22 com ponto central, com triplicata em todos os pontos. Como resultado foi obtido que o melhor ponto foi na condição experimental E(50,200) (relativo a 50% etanol e 200 °C), com 80,36% de lignina extraída e 91,35% de rendimento da celulose.
Biomass has gained prominence as a renewable raw material for obtaining chemicals and energy, in front of a competitive industry based on fossil sources. In Brazil, forest biomass is widely cultivated, whether in the construction and manufacturing of furniture, or in energy production and paper production. Eucalyptus is the most important forest biomass in terms of cultivation in Brazil (38.1 m³ / ha / year in 2015) and in the world. In the last decades, we have sought to deconstruct lignocellulosic biomass, such as wood, in its constituent polymers, cellulose, hemicellulose and lignin, so that each can be processed in order to generate products with higher benefit. In this context, we have the organosolv process, which is a pretreatment of the lignocellulosic biomass with the mixture of organic solvents and water at high temperatures. In addition to fractionating biomass, it is possible to obtainm from the organosolv process, components with high purity and more reactive for future applications. The objective of this work was to study the effect of temperature (evaluated between 180 °C and 220 °C) and ethanol / water ratio (evaluated between 30% and 70% v/v) in the organosolv process applied to samples of Eucalyptus grandis, being observed how much of each of the polymers was removed from the initial solid sample. The experiments were performed according to a factorial 22 experimental design with center point, with triplicate at all points. As a result it was obtained that the best point was in the experimental condition E(50,200) (relative to 50% ethanol and 200 °C), with 80.36% lignin extracted and 91.35% cellulose yield.
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Yawalata, Dominggus. "Catalytic selectivity in alcohol organosolv pulping of spruce wood." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ61209.pdf.
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Bianchi, Maria Lucia. "Polpação de palha de milho, utilizando-se diferentes processos organosolv." [s.n.], 1995. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249491.
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Orientador: Ulf F. SchuchardtDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica
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Mestrado
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Muurinen, E. (Esa). "Organosolv pulping:a review and distillation study related to peroxyacid pulping." Doctoral thesis, University of Oulu, 2000. http://urn.fi/urn:isbn:9514256611.
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Abstract
More than 900 papers related to organosolv pulping have been
reviewed in this thesis. From the information included in those
papers it can be concluded that organosolv pulping processes are
still in a developing stage and are not yet ready to seriously threat
the position of the kraft process as the main pulp manufacturing
process in the world.
Distillation seems to be the main alternative as the process
for recovering the solvent in organosolv pulping. A good reason
for this is that using simple distillation no potentially harmful
components are introduced to the process.
The effect of feed composition on the operation of a separation
sequence in an organosolv process using aqueous formic and acetic
acids and corresponding peroxyacids was studied. When simple distillation
was used as the separation method the effect was found to be significant.
The no ideal nature of the formic acid-acetic acid-water mixture,
which separation was studied, makes the ternary composition space
to divide into four distillation regions. Which region the feed
is located in, obviously determines the economy of the distillation
sequence.
Shortcut calculation methods cannot be recommended to be
used for designing a distillation sequence for the ternary mixture
studied, but they give useful information for the comparison of
such sequences. They were used to choose a limited number of alternatives
for studies with rigorous calculation methods.
Minimum work of separation can also be used to make a satisfying
estimate for the relative easiness of separation of the formic acid-acetic
acid-water mixture.
Thermal integration using pinch technology was also tested
and found very useful for decreasing the thermal energy consumption
of distillation processes.
Thermodynamic efficiencies for separating the formic acid-acetic
acid-water mixture by simple distillation were estimated. They were
found to be lower than the average value for distillation presented
in literature.
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Maza, Lisa Jésus. "Résines vertes à base de lignine organosolve." Thesis, Pau, 2017. http://www.theses.fr/2017PAUU3039.
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Les résines phénoliques, sont entre autres utilisées dans l’industrie du bois pour la fabrication de panneaux de particules ou de contreplaqués, après des étapes d'encollage, d'imprégnation et/ou de pressage à chaud. Elles sont principalement obtenues par polymérisation par étapes (polycondensation) à partir de formaldéhyde et de phénol. Ces deux matières premières de base sont actuellement des produits issus de la pétrochimie.Ce travail de thèse Cifre, en partenariat avec la société Rolkem, spécialisée dans la conception et la fabrication de résines phénoliques de type résol, a pour objectif la réduction de l’utilisation de matières pétrochimiques via la substitution du phénol par une bioressource telle que la lignine. Cette dernière a une structure phénolique et une similarité structurelle avec le réseau des résines phénoliques, elle est abondante dans la nature et disponible. Pour atteindre l’industrialisation de ces nouvelles résines biosourcées, une étude sur la compréhension des mécanismes réactionnels qui gouvernent le procédé a été menée avant d’optimiser le protocole permettant l’incorporation de la lignine dans les résines.Il a été possible de remplacer jusqu’à 50%m du phénol par de la lignine organosolve et de réduire la concentration initiale en formaldéhyde. En utilisant une lignine Kraft il a été possible de remplacer jusqu’à 75%m du phénol et de réduire jusqu’à 30%m du formaldéhyde utilisé, par rapport aux résines classiques de référence, tout en respectant le cahier des charges imposé par Rolkem. Ces résultats ont été possibles grâce à des suivis cinétiques des procédés et des études de réactivité de la lignine. Grâce à ces travaux de thèse, le transfert d’échelle des résines biosourcées du laboratoire au pilote industriel a été possible, tout en respectant les contraintes industrielles telles que la productivité, la qualité, la sécurité et l’environnement. De plus, les essais industriels de collage de contreplaqués réalisés sont conformes aux prérequis.En complément des objectifs fixés par le projet, et de manière plus académique, la réactivité de la lignine vis-à-vis du formaldéhyde a été étudiée en chauffage conventionnel et sous irradiation microonde. Cette étude complémentaire permet de corréler la réactivité lignine-formaldéhyde et mode de chauffage et d’atteindre spécifiquement des produits issus de réactions d’addition ou de condensationPhenolic resins, may be used in the wood industry for the manufacture of particle boards or plywood, after gluing, impregnation and/or hot-pressing steps. They are mainly obtained by step polymerization (polycondensation) from formaldehyde and phenol. These two raw materials are currently petrochemicals.This thesis work, supported by Rolkem, a company specialized in the design and manufacture of resol type phenolic resins, aims to reduce the use of non-biobased materials by replacing phenol with lignin exhibiting a phenolic structure and a structural similarity with the network of phenolic resins. Lignin is abundant in the environment and easily available. To achieve the industrialization of these new biobased resins, a study on the understanding of the reaction mechanisms has been carried out to favor the incorporation of lignin within the resins. It has been possible to replace up to 50wt.% of the phenol with organosolve lignin and to reduce the initial concentration of formaldehyde at the same time. 75wt.% substitution has been achieved using a Kraft lignin by reducing up to 30wt.% of the formaldehyde concentration as compared to conventional resins. The new biobased resins respect the Rolkem specifications. Thanks to this work results, the scale transfer of biobased resins from the laboratory scale to the industrial pilot was possible, while respecting industrial constraints such as productivity, quality, safety and environment. In addition, the industrial plywood bonding tests were in accordance with the prerequisite.In addition to the above objectives the reactivity of BiolignineTM with formaldehyde has been studied under conventional heating and microwave irradiation. This complementary study allows the correlation of the lignine-formaldehyde reactivity and the heating modes to specifically reach products resulting from addition or condensation reactions
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Muurinen, Esa. "Organosolv pulping a review and distillation study related to peroxyacid pulping /." OuLu : Oulun yliopisto, 2000. http://catalog.hathitrust.org/api/volumes/oclc/47152371.html.
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Tan, Xin. "Effect of Organosolv Lignin and Extractable Lignin on Enzymatic Hydrolysis of Lignocelluloses." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1613752000022518.
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Chao, Hsiu-Yi. "Luminescent organogold(I) complexes with electron rich bulky phosphine ligands : synthesis and spectroscopic studies /." Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk/hkuto/record.jsp?23242309.
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Hess, Fiona Millicent. "Halo- and organogold(I) complexes as potential metallomesogens." Master's thesis, University of Cape Town, 1999. http://hdl.handle.net/11427/9757.
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Includes bibliography.There is currently much interest in how the properties of liquid crystals may be altered by metal atoms. Gold(I) complexes of the type RAuL have recently been shown to exhibit interesting liquid crystal behaviour. As molecular structure and intermolecular forces play a major role in liquid crystal chemistry, changing the nature of the R and L groups result in changes mesomorphic properties. The aim of the project was to synthesise RAuL complexes with stilbazole ligands and to investigate how different R groups influence the liquid crystal properties. ClAu(n-OST) complexes, n-OST = trans-4,4'-alkoxystilbazole with n = number of carbon atoms in the alkoxy chain, were synthesised from ClAu(tht) and n-OST. They were found to exhibit smectic A mesophases, melting between 135-153 °C and decomposing at the clearing point at 168-180 °C. The transition temperatures decreased as the chain length of the n-OST ligand increased.
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Schwiderski, Martin [Verfasser], Herbert [Akademischer Betreuer] Vogel, and Andrea [Akademischer Betreuer] Kruse. "Aluminiumchlorid katalysierter Organosolv-Aufschluss von Lignocellulosen / Martin Schwiderski ; Herbert Vogel, Andrea Kruse." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2017. http://d-nb.info/1131254201/34.
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El, Hage Roland. "Prétraitement du miscanthus x giganteus : vers une valorisation optimale de la biomasse lignocellulosique." Thesis, Nancy 1, 2010. http://www.theses.fr/2010NAN10063/document.
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Le miscanthus x Giganteus (MxG) constitue, du fait de sa composition, une source renouvelable de matière lignocellulosique pouvant être d'un grand intérêt pour la production de molécules à haute valeur ajoutée. Le MxG ayant servi à ce travail provient du lycée agricole à Courcelles-Chaussy, Metz-France. Sa teneur élevée en hémicelluloses (26 %), en lignine (26 %) et en cellulose (36 %) en fait une bonne source de polymères et de carburant renouvelable. L'étude que nous avons réalisée a été menée dans le but de caractériser la paille de MxG et d'optimiser le processus de délignification en une seule étape (1) par un traitement organosolv à l'éthanol et en deux étapes (2) par un prétraitement consistant en une autohydrolyse à l'eau/organosolv. Le procédé éthanol organosolv a permis un bon fractionnement des trois constituants de la biomasse (la lignine, la cellulose et les hémicelluloses). Le procédé de traitement en deux étapes, impliquant une autohydrolyse à l'eau (en présence et en l'absence du 2-naphtol), préalable au traitement organosolv, a permis de faciliter l'étape ultérieure de délignification en déstructurant la lignine. Une investigation portant sur la structure physico-chimique a été réalisée sur de la lignine de bois broyé et de la lignine organosolv de MxG extraite à différentes sévérités de traitement. Nous nous sommes ensuite intéressés à utiliser la lignine organosolv pour la formulation d'un adhésif pour le bois dans laquelle un aldéhyde non toxique et peu volatile (le glyoxal) est employé en remplacement du formaldéhyde. Une formulation, composée à 100 % de résines naturelles (60 % de tannins de mimosa et 40 % de lignine glyoxalée) a été utilisée pour la conception d'un panneau de particules et a donné des résultats prometteurs avec une force de liaison interne de 0,41 MPa, supérieure à la valeur de la norme européenne en vigueur. Enfin, une étude des propriétés antioxydantes a été faite sur les lignines extraites. Les résultats obtenus ont montré une corrélation entre l'activité antioxydante et les conditions opératoires du traitement organosolv, la masse moléculaire moyenne, l'indice de polydispersité et les groupements hydroxyles phénoliques des ligninesMiscanthus x giganteus (MxG) is, because of its composition, a source of renewable lignocellulosic material that can be of great interest for the production of high added value molecules. MxG used in this work comes from the agricultural high school of Courcelles-Chaussy, Metz-France. Its high content of hemicelluloses (26 %), lignin (26 %) and cellulose (36 %) makes it a good source of polymers and renewable fuel. In the present study we have characterized the straw of MxG and optimized the process of delignification in a single step (1) by an ethanol organosolv treatment and in a two steps (2) including an autohydrolysis pretreatment with water / organosolv. The ethanol organosolv process permits a good separation of the three constituents of our biomass (lignin, cellulose and hemicelluloses). The two steps treatment process, involving an autohydrolysis with water (in the presence or absence of 2-naphthol) before the pretreatment organosolv has facilitated the later stage of delignification in destructurizing the lignin. An investigation of the physico-chemical properties was performed on the structure of the milled wood lignin and organosolv lignin of MxG extracted with different treatment severities. A way of valorization for the organosolv lignin has been proposed by their incorporation in the formulation of an adhesive for wood in which a non volatile and low toxic aldehyde (glyoxal) is used instead of formaldehyde. A formulation consisting in 100 % of natural resins (60 % tannins of mimosa and 40 % of glyoxalated lignin) was used for the production of particle board and gave promising results with internal bond strength of 0.41 MPa, higher than the value of the current European standard. Finally, a study was conducted on the antioxidant properties of organosolv lignin extracted at different severities. The results have shown a correlation between the antioxidant activity and the operating conditions of treatment organosolv, the average molecular weight, the polydispersity index and the phenolic hydroxyl groups of lignin
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Behera, Nikhil Chandra. "Topochemistry of delignification and its effect on fiber properties of spruce organosolv pulp." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/25561.
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The catalysed organosolv process is a novel method of pulping that has many advantages over other chemical pulping processes. One of the most important advantages is its 6-12 percentage point higher yield of pulp in comparison to other chemical pulping processes. Short cooking time, low disintegration and refining energy requirements, ease of pulp washing and simplified method of by-product recovery are some of the other advantages. However, due to differences in the chemical nature of the cooking liquor, the basic properties of the fibers differ considerably.
In this thesis a detailed study has been carried out on some of the unique phenomena i.e., fiber liberation at a high yield, topochemical preference of delignification and their manifestation on morphology and strength properties of fibers.
Pulping results show that softwoods can be pulped easily to a high pulp yield (60%) with a high viscosity of cellulose of 50 mPas. The observed delignification pattern indicates two distinct stages both having first order kinetics. By this process, fast delignification occurs in the bulk delignification stage within which about 70% of the lignin is removed. Loss of residual lignin occurs at a slower rate in the residual delignification stage.
The ease of penetration of the cooking liquor and preferential removal of lignin from the middle lamella result in complete fiber liberation at a pulp yield of 57.3% and a Kappa number of 72 (7% residual lignin). The loss of lignin to carbohydrate ratio at 57.3%pulp yield is 1.21:1.
The topochemistry of delignification in organosolv pulping is limited to a preferential removal of lignin from the cell corner and middle lamella regions rather than from the secondary wall. In the initial stages of pulping, lignin removal is mostly from the cell corner and middle lamella region. Secondary wall lignin was removed quite slowly and a substantial amount of lignin remained in the secondary wall even after extended delignification. This can be accounted for by the slow hemicellulose removal (loss) from the secondary wall.
The relatively high residual lignin retained in the cell corner in comparison to the complete delignification in the middle lamella raises questions about chemical differences and solubility characteristics of the cell corner lignin.
The fibers of high-yield pulps are found to be stiffer and form a low density paper with high tear, and average burst and tensile strength. These factors can be correlated with the higher amount of residual lignin material in the fiber secondary wall and the low bonding properties of the fibers. High residual lignin content decreases the internal fibrillation and ability of the fibers to conform with each other during sheet formation. On the other hand, the low-yield fibers (49.8%) were found to be quite flexible and showed higher strength than obtainable with high yield pulps. Organosolv handsheets contain 20 to 30% fewer fibers than kraft papers of the same basis weight. However, the apparent difference in strength properties between organosolv and kraft papers is not disproportionately large.
Organosolv lignins isolated from the spent liquor have low molecular weight (1400-2400) and low polydispersity (1.95) when recovered from extended pulping liquors. This indicates that most of the lignin is degraded to a fairly uniform low molecular weight polymer without substantially affecting the reactivity of the natural lignin as it occurs in the native fibers.
The simplicity of the pulping process together with the comparable strength properties of the fibers even at higher yields, reveals large potentials of this method as a new pulping process. With some refinements and closer optimization, pulp fully acceptable commercially could be produced by this process.Forestry, Faculty of
Graduate
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趙修毅 and Hsiu-Yi Chao. "Luminescent organogold(I) complexes with electron rich bulky phosphineligands: synthesis and spectroscopicstudies." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31241499.
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la, Placa Antonia. "Comparison of Miscanthus grass lignin with spruce lignin from organosolv process for nanoparticles production." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278835.
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There is a growing global energy demand and the society is forced to shift towards renewable energy sources due to the depletion of fossil fuels. Lignocellulosic biomass is a renewable resource available in vast amounts and could therefore have the potential to become a primary source for fuel production. Lignin, as a substantial part of the biomass, is underutilized due to its complex structure which can limit the potential of applying lignin towards value- adding products. However, one way to promote lignin valorization is to produce lignin nanoparticles (LNPs) that are considered valuable in the biomedical field. The aim of this report was to investigate if different botanical origins will affect the properties of LNPs, such as size, polydispersity index, 𝜁-potential and morphology. LNPs from Miscanthus sinensis grass lignin, obtained by the organosolv process, was successfully produced via solvent exchange and compared with LNPs from spruce organosolv lignin. The experimental part resulted in Miscanthus LNPs ranging from 133.7 to 377.4 nm, where a higher initial concentration yielded larger particles, and the average ζ- potential was -38.7 mV. This work has shown that the botanical origin will affect both size and shape of LNPs produced with the same method. Miscanthus LNPs were larger in size and ellipsoidal in shape compared to the spherical spruce LNPs. The lignin concentration influenced the particle size for both origins and the difference in LNP size became more significant as the concentration increased. However, to only explore two different types of plant origins is not sufficient enough to reach a general conclusion. Also, there are many influential steps from plant origin to LNP and to reach a more generalized conclusion, it is arguable that there is a necessity to explore and determine both the applied pulping method, the process to isolate the lignin and the method used to produce the LNPs.Det globala energibehovet ökar och samhället tvingas därmed att växla till förnybara resurser eftersom de fossila bränslena kan ta slut. Biomassa är en förnybar resurs som finns tillgänglig i stora mängder och kan därför bli en potentiell primär energikälla. Lignin, som är en väsentlig del av biomassan, används inte i lika stor utsträckning på grund av dess komplexa struktur. Komplexiteten begränsar därför användandet av lignin i värdeskapande produkter. Men en väg för att ta tillvara på lignins värdefulla egenskaper kan vara framställandet av nanopartiklar (NP), vilket öppnar upp för användning av lignin inom det biomedicinska fältet. Syftet med den här rapporten är att undersöka om lignin från olika botaniska ursprung påverkar nanopartiklarnas egenskaper, som exempelvis storlek, polydispersitet, 𝜁-potential och morfologi. NP av lignin från gräsarten Miscanthus sinensis framställdes genom solvent exchange och jämfördes sedan med NP från granlignin. Både miscanthus- och granligninet var isolerat genom organosolvprocessen. Den experimentella delen av arbetet visade att NP from miscanthuslignin gav partiklar inom intervallet 133.7 to 377.4 nm, där högre koncentration gav större partiklar, och medelvärdet för 𝜁-potentialen var -38.7 mV. Resultatet från arbetet visade att det botaniskt ursprunget påverkar både storleken och formen på NP av lignin som framställts med samma metod. NP från miscanthuslignin var större och hade en mer elliptisk form, i jämförelse med de mer sfäriska partiklarna från granlignin. Ligninkoncentrationen påverkade partikelstorleken för båda typerna av lignin, dessutom blev skillnaden i partikelstorlek större när koncentrationen ökade. Däremot var det svårt att dra någon generell slutsats genom att bara undersöka två olika ursprung. Eftersom det finns flera steg i processen från växters ursprung till NP av lignin som kan påverka partiklarnas egenskaper kan det vara nödvändigt att utforska både den tillämpade massaprocessen, isoleringsmetoden och metoden som används för att framställa NP av lignin.
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Sonesson, Elin. "Investigation of Probiotic Organogel Formulations for use in Oral Health." Thesis, Linnéuniversitetet, Institutionen för kemi och biomedicin (KOB), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-28438.
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The aim of the project is to investigate how a more viscous, gel like formulation can be made of BioGaia´s Prodentis Drops, which is a probiotic product for oral use. The two different strains of Lactobacillus reuteri that are used in the product, together called L. reuteri Prodentis, have been clinically proven to be effective in treatment of gingivitis and caries formation. The existing product is a highly liquid oil suspension that has been described as too runny and difficult to get into tooth pockets and between teeth. Therefore a gel formulation would be preferred. Pre-trials were excecuted to see what combinations and quantities of ingredients could work. Three different formulations using 3 %, 5 % and 7 % beeswax as thickening agent proceeded to another round of trials, as well as one formulation where the original oil was exchanged for hydrogenated rapeseed oil. In the beeswax formulations fumed silicon dioxide was being used as well. Three different analyses were executed, considering bacterial survival, viscosity and phase separation of gels. The bacterial survival proved to be acceptable in all samples even after 14 days of incubation in 37oC. The formulation with 7 % beeswax was the most viscous one, followed by 5 % beeswax, 3 % beeswax and the formulation with hydrogenated oil, respectively. Phase separation could be seen in the hydrogenated oil formulation already after seven days and even more so after 14 days. There were also signs of separation in the formulation with 3 % beeswax after 14 days. It was concluded that in further development of the Prodentis Drops it is recommendable to proceed with the 5 % beeswax formulation.
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Heathcote, Robert. "Synthesis and application of organogold precursors for direct laser writing." Thesis, Keele University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.502939.
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Lucht, Julie. "Viscosity Characterization of 20% Pluronic Lecithin Organogel at varying pHs." The University of Arizona, 2009. http://hdl.handle.net/10150/623980.
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Class of 2009 AbstractOBJECTIVES: The primary objective of this experiment was to characterize the pH stability range of 20% Pluronic lecithin organogel (PLO). We intended to determine the viscosity at varying pHs. We prepared six samples of 20% PLO. METHODS: An initial rheological reading of each sample was recorded by a dynamic stress rheometer. Each sample was titrated drop-wise with citric acid or KOH in 0.5 pH increments. When the desired pH was obtained, a 0.5 mL sample was analyzed with a dynamic stress rheometer, RS-200, using Rheos software. RESULTS: Since PLO is a non-Newtonian substance, viscosity changed relative to shear stress and we were not able to examine a correlation of pH with viscosity. Instead we inputted the data into Microsoft Excel® and plotted a shear stress versus viscosity curve for each sample to identify trends. CONCLUSIONS: We were unable to achieve our primary objective of determining the viscosity characterization of 20% PLO at varying pHs due to the non-Newtonian nature of the material. Subjectively, we determined the viscosity of 20% PLO is not substantially affected by pH. Other factors such as temperature, excess liquid, and surfactant ability may influence viscosity and need to be examined in the future.
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Price, Gregory Arthur. "Routes to organogold compounds and gold catalysed A3-coupling reactions." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/routes-to-organogold-compounds-and-gold-catalysed-a3coupling-reactions(4b552b2f-0053-4449-9421-71116441850c).html.
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A new route to the synthesis of cyclometallated gold(III) complexes containing functionalised (2-dimethylaminomethyl)phenyl ligands is described. The synthesis of 2-Me2NCH2-C6H4AuCl2 (8a), 2-Me2NCH2-5-CH3-C6H3AuCl2 (49), 2-Me2NCH2-5-CF3-C6H3AuCl2 (50) and 2-Me2NCH2-5-OMe-C6H3AuCl2 (51) has been accomplished via transmetallation from the corresponding boroxines to sodium tetrachloroaurate in aqueous acetonitrile. This protocol gives comparable yields to those obtained via transmetallation from an organomercurial. However this route is advantageous as it avoids the use of extremely toxic mercury compounds. The novel bimetallic tin(IV) complexes 1,4-(SnPh3)2-2,5-(NMe2CH2)2-C6H2 (66),1,4-(SnMe3)2-2,5-(NMe2CH2)2-C6H2 (67) and 1,4-(SnMe2Cl)2-2,5-(NMe2CH2)2-C6H2 (68) have been synthesised by in-situ quenching of 1,4-(Li)2-2,5-(NMe2CH2)2-C6H2 (57) with two equivalents of ClSnPh3, ClSnMe3 or Cl2SnMe2 respectively. Transmetallation from 1,4-(SnMe2Cl)2-2,5-(NMe2CH2)2-C6H2 (68) with two equivalents of sodium tetrachloroaurate in refluxing acetonitrile resulted in the formation of the relatively insoluble di-gold(III) complex 1,4-(AuCl2)2-2,5-(NMe2CH2)2-C6H2 (71). The novel bisphosphine 1,4-(PPh2)2-2,5-(NMe2CH2)2-C6H2 (69) has also been prepared by in-situ quenching of 1,4-(Li)2-2,5-(NMe2CH2)2-C6H2 (57) with two equivalents of ClPPh2. 69 was reacted with ClAu(THT) to form the novel di-gold(I) phosphine complex 1,4-(ClAuPPh2)2-2,5-(NMe2CH2)2-C6H2 (70) in excellent yield. The catalytic activity of a variety of gold(I) and gold(III) complexes in the A3-coupling of aldehydes, amines and alkynes has been investigated. 2-Me2NCH2-C6H4AuCl2 (8a) was found to be an effective catalyst for A3-couplings, with H2O as solvent, giving essentially quantitative conversions after 24 h. The couplings were tolerant to a diverse range of substrates. A range of chiral Au(III) and Au(I) complexes were prepared and screened in the reaction of benzaldehyde, dibenzylamine and phenylacetylene. In all cases no discernible ee was observed. A series of A3-coupling reactions catalysed by 8a, Na[AuCl4] .2H2O and [AuCCPh]n (139) were also monitored by 1H NMR spectroscopy and this data suggests a common, catalytically active species, is formed during these reactions. The addition of PPh3 to the gold catalysed couplings was found to severely retard the reactions. In contrast the use of chloroform as the solvent resulted in significant improvements to the rate of reaction. Overall the data collected provides a mechanistic insight into the development of asymmetric A3-coupling reactions. The evidence suggests that a single universal catalytically active acetylide species is formed from both Au(I) and Au(III) precursors.
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Del, Rio Luis Fernando. "Substrate properties that influence the enzymatic hydrolysis of organosolv-pretreated softwoods at low enzyme loadings." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/43720.
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Lignocellulosic biomass is a potential source of sugars for the production of fuels and chemicals. However, its resistance to chemical and biological degradation poses a significant challenge. Consequently, a pretreatment is required to increase the accessibility of cellulose to cellulases. The organosolv process is one of the few pretreatments that can process softwoods to generate substrates that are readily hydrolyzed by cellulases. However, because the residual lignin and hemicelluloses can restrict cellulose accessibility, obtaining significant cellulose conversion at low enzyme loadings (< 5 FPU g-¹ cellulose) remains a challenge. As complete delignification is not economically viable, we hypothesize that other substrate properties could be altered to reduce the recalcitrance of organosolv-pretreated softwoods.
The initial work reported in this thesis compared the effects of pretreatment severity on the physico-chemical properties and enzymatic hydrolysis of organosolv-pretreated lodgepole pine and hybrid poplar (a representative hardwood). As expected, hybrid poplar was less recalcitrant than lodgepole pine. However, unlike lodgepole pine, which remained unaffected by changes in pretreatment severity, the recalcitrance of hybrid poplar increased with pretreatment severity. Interestingly, it was found that this increased recalcitrance was due to non-productive binding between lignin and cellulases. In contrast the inhibitory effect of lignin on the enzymatic hydrolysis of lodgepole pine was due to a combination of restricted cellulose accessibility and hydrophobic interactions between lignin and cellulases.
Subsequent studies showed that rather than a single substrate characteristic such as lignin content, particle size or cellulose degree of polymerization, the overall cellulose accessibility is the key substrate characteristic that governs the susceptibility of the organosolv-pretreated substrates to enzymatic hydrolysis. Surprisingly, attempts to increase cellulose accessibility through PFI-mill refining were unsuccessful. However, increasing the hydrophilicity of the residual lignin via neutral sulphonation resulted in significant increases in enzymatic hydrolysis at 5 and 2.5 FPU g-¹ cellulose (from 80% to 95% and from 35% to 80%, respectively). This was likely due to decreased nonspecific interactions between the sulphonated lignin and cellulases. Overall, the results suggest that increasing the hydrophilicity of the residual lignin could be a viable strategy to reduce the recalcitrance of organosolv-pretreated softwoods.
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Lin, Mandy. "Investigation of a two-stage steam/organosolv pretreatment approach for the fractionation of softwood biomass." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/60234.
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In order to improve the economic viability of a bioconversion process it would be extremely beneficial to maximize the recovery of all of the lignocellulosic components while enhancing enzyme accessibility to the cellulosic component. Wood residue derived pellets are already a prominent Canadian commodity and the existing supply-chain produces a high density, low moisture feedstock suitable for mass collection and transport. However, pellets are almost exclusively used for combustion and not as a possible biorefinery feedstock. As a result, there is limited information on the influence of the pelletization process (e.g. grinding, drying, compressing) on the susceptibility of pellets, as opposed to chips, to the various pretreatment, fractionation and cellulose hydrolysis steps that are components of a typical bioconversion process. The work described in the thesis assessed the potential of a two-stage steam/organosolv pretreatment process to fractionate and isolate the hemicellulose and lignin components from softwood pellets, yielding a more accessible, cellulose-rich substrate. Various steam pretreatment conditions were compared for their ability to enhance hemicellulose solubilisation while minimizing lignin condensation (first-stage), to improve subsequent organosolv delignification (second-stage). Carbocation scavengers were compared for their ability to minimize lignin condensation during either stage. When softwood chips and pellets were compared, the effectiveness of the pretreatment was determined by hemicellulose solubilisation, delignification capability and the ease of enzymatic hydrolysis of the cellulosic component. It was apparent that pellets were more responsive than chips to pretreatment due to their smaller particle size, which facilitated both hemicellulose solubilisation and delignification. At conditions that solubilized and recovered hemicellulose, acid-catalyzed steam pretreatment induced lignin condensation. This impeded subsequent organosolv delignification and enzymatic hydrolysis. The addition of lignosulfonates as a potential carbocation scavenger during acid-catalyzed steam pretreatment resulted in increased hemicellulose solubilisation and carbohydrate recovery while improving delignification during subsequent organosolv treatment. Adding lignosulfonates during acid-catalyzed steam pretreatment also enhanced enzymatic hydrolysis. It was likely that the added lignosulfonates increased lignin hydrophilicity which facilitated lignin dissolution and decreased non-productive enzyme inhibition. It was apparent that the addition of lignosulfonates prior to pretreatment reduced the detrimental effects of lignin condensation which benefited subsequent fractionation of the pretreated biomass.Forestry, Faculty of
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Roberts, Peter Grant. "The laser chemical vapour deposition of gold from organogold (I) precursors." Thesis, Heriot-Watt University, 1993. http://hdl.handle.net/10399/1289.
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Cookson, Peter D. "Synthesis and characterization of triorganophosphinegold (I) thiolates /." Title page, contents and abstract only, 1993. http://web4.library.adelaide.edu.au/theses/09SM/09smc7735.pdf.
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Hidalgo, Gómez Hernán, and Valdivia Osvaldo Soto. "Organos de la administración que ejercen jurisdicción en Chile." Tesis, Universidad de Chile, 2000. http://www.repositorio.uchile.cl/handle/2250/114203.
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Memoria (licenciado en ciencias jurídicas y sociales)No autorizada por el autor para ser publicada a texto completo
Esta memoria pretende demostrar que la facultad de juzgamiento no se encuentra radicada exclusivamente en el Poder Judicial. Por razones de índole histórica, jurídica o práctica, hay variados órganos pertenecientes a la Administración del Estado que hoy ejercen una clara y definida función jurisdiccional, toda vez que conocen, juzgan y hacen ejecutar las resoluciones dictadas por ellos, a fin de solucionar la litis que se les presenta a su conocimiento. El juzgamiento por órganos que no sean tribunales de justicia podría parecer inconstitucional. Sin embargo, nuestra Carta Magna establece, además de la justicia ordinaria, una justicia electoral, otra constitucional e incluso otorga facultades juzgadoras a un órgano netamente administrativo como es la Contraloría General de la República.
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Quinde, Abad Augusto. "Behaviour of the major resin- and fatty acids of slash pine (Pinus elliottii) during organosolv pulping." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/30658.
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A high extractive-content temperate conifer wood (Pinus elliottii) was examined as a pulpwood source by organosolv pulping. Particularly, the behavior of the resin- and fatty acids during the lignin solvolysis process was studied in detail. For this purpose the resin-and fatty acids were characterized in the wood, and after pulping trials in order to reveal their fate during pulping, using catalyzed 80% aqueous alcohol (methanol) as solvent.
Wood extractives were removed by both methanolic cold maceration and Soxhlet extraction techniques. The resin-and fatty acid fractions thus collected were saponified and/or methylated and characterized by gas liquid chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). No significant differences were found in regard to extraction efficiencies between the two types of cold extractions. Furthermore, there was no significant difference between these two types of cold extractions in comparison with the procedure described by TAPPI standard T 204 os-76.
Pulping experiments were performed at 205°C for periods of 5, 20, 40, and 60 min. Lignins, which precipitated on cooling of the black liquor (Lignin fraction I), were set aside for further extractions and chemical analyses. The molecular weight distribution of these lignins was determined by size exclusion chromatography on an HPLC and their quantity was determined either gravimetrically or volumetrically.
Precipitated Lignin Fraction I, suspected of containing some adsorbed extractives and some fiber fragments, was transferred to a tared crucible. The lignin and extractives were sequentially dissolved by using tetrahydrofuran (THF), acetone and methanol. This solution was evaporated, the residue redissolved in methanol-water (80:20) and the solution liquid-liquid extracted with diethyl ether in a separatory funnel followed by methylation prior to GC and GC-MS analysis.
Quantification of the resin- and fatty acids in the wood and those recovered after organosolv pulping was performed using an internal standard (methyl heptadecanoate) added prior to the extraction steps.
The extractives dissolved in the black liquor were isolated by a ternary liquid-liquid extraction scheme using diethyl ether, methylated with fresh diazomethane, and the resin- and fatty acids methyl esters characterized by GC and GC-MS. The extractives present in the pulp were isolated (removed) by a Soxhlet extraction procedure with methanol and" the resin- and fatty acids fractions characterized as above. Resin- and fatty acids surviving the high-temperature pulping process, were found mainly in the black liquor. After the 60 min cook, the black liquor contained 78.1% and 71.6% of resin- and fatty acids, respectively, while the pulp retained 11.7% and 8.2%, respectively of the extractives originally present in wood. "Lignin fraction I" adsorbed 10.2% and 20.2% of the resin- and fatty acids, respectively. Contrarily, if all of the lignin is precipitated (Lignin fraction II). prior to liquid/liquid extraction of the black liquor with diethyl ether, 98% and 60.4% of the resin- and fatty acids co-precipitate with the lignin and 2.0% and 39.6%, respectively, remain dissolved in the aqueous filtrate.
Industrial organosolv lignin isolated after solvent pulping of pine was thus shown to contain most (98%) of the resin acids and 39.6% of the fatty acids normally found in pines. Although not tested, it is supposed that lignins isolated by precipitation from the black liquor after organosolv pulping of other species cannot be considered as "pristine lignins" as described hitherto in the technical literature, since such lignins are heavily contaminated by the extractives of the wood species. In light of these findings all data on chemical and physical characterization of organosolv lignins and their reactivity will have to be reexamined and reassessed to remove the effect of the extractives as contaminants.Forestry, Faculty of
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Lai, Thanh Loan. "Organogels photoactifs : Synthèse, structuration et propriétés." Thesis, Angers, 2014. http://www.theses.fr/2014ANGE0012/document.
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Ce travail de thèse a pour objet l’étude d’organogélifiants bis(urée) originaux de faible masse moléculaire (LMWG), intégrant ou non des unités fluorescentes pyrènes. Il intègre les aspects liés à la synthèse organique de ces systèmes, l’étude de leur capacité de gélification pour des solvants variés, la caractérisation des édifices auto-assemblés correspondants -en particulier à l’aide de méthodes spectroscopiques et de microscopies variées-, et enfin la mise en œuvre d’une méthode originale de structuration par alignement des fibres auto-assemblées. Deux premiers organogélifiants bis(urée) modèles ont été synthétisés et leur aptitude à geler de multiples solvants ainsi que la structuration des auto-assemblages correspondant ont été étudiées en détail (RMN, microscopies optiques et électroniques). L’étude de l’alignement des fibres résultantes a été réalisée avec succès en utilisant un gabarit, par remplissage des pores d’une membrane d’alumine, puis dissolution de cette dernière. Une seconde série d’organogélifiants bis(urée), intégrant cette fois une, deux ou encore trois unités fluorescentes pyrène a été synthétisée. L’intégration covalente de cette unité dans nos gels s’est révélée intéressante à plusieurs titres. D’abord, celle-ci joue le rôle de sonde interne permettant une caractérisation approfondie de la structuration des édifices auto-assemblés à l’aide des spectroscopies d’absorption et d’émission en fonction de la température. Cette unité participe par ailleurs à la robustesse des objets nanostructurés, comme remarquablement mis en évidence dans les gels hybrides associant les gélifiants tris(pyrényles) de symétrie C3, soit à un gélifiant porteur de deux unités pyrène ou soit à un dérivé accepteur-π d’électrons, introduit dans le milieuThis thesis focuses on the study of original bis(urea) low molecular weight organogelators (LMWG), integrating or not fluorescent pyrene units. This study integrates organic synthesis of these systems, study of their gelling capacity for various solvents, characterization of the corresponding self-assembled structures through various spectroscopic and microscopy techniques, and finally implementation of an original structuring method by alignment of the self-assembled fibers. Two first model bis(urea) organogelators were synthesized and their ability to gel multiple solvents as well as the structuration of the corresponding self-assemblies have been studied in detail (NMR, optical and electron microscopy). Alignment of the resulting fibers has been successfully performed using a template method, by filling the pores of an alumina membrane, followed by dissolution of the latter. A second series of bis(urea) organogelators, which incorporate one, two or three pyrene fluorescent units was synthesized. The integration of this unit in our gels has proved useful in several ways. First, it acts as an internal probe for further characterize the resulting self-assembled structures, using variable temperature absorption and emission spectroscopies. The pyrene unit also contributes to the robustness of the nanostructured objects, as remarkably evidenced in hybrid gels involving tris(pyrenyl) C3 symmetry gelators associated to either a bis(pyrenyl) gelator or to a π-acceptor derivative
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Quinelato, Cristiane [UNESP]. "Métodos de extração da lignina do bagaço da cana-de-açúcar do Noroeste do Estado de São Paulo." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/138898.
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O Brasil é o maior produtor mundial de cana-de-açúcar, e com isso é também o maior gerador de biomassa residual – bagaço e palha. Uma grande parte dessa biomassa é utilizada na co-geração de energia, sendo queimada nas caldeiras das usinas, porém ainda há um enorme excedente, gerando problemas ambientais e sociais. Por isso, é necessário desenvolver projetos para utilização desse material, com valor agregado. Uma das maneiras é a utilização dos compostos que compõem a fibra do bagaço: celulose, hemicelulose e lignina. Para viabilizar a utilização desses compostos são necessárias técnicas pouco nocivas e com custo reduzido. Além disso, é importante que durante o processo de extração, haja pouca alteração estrutural dos compostos, ou que as alterações sofridas sejam benéficas para sua utilização posterior. O presente trabalho visou desenvolver métodos diferentes de extração de uma das frações dessa fibra, a lignina, avaliando as alterações sofridas durante os processos de extração para um posterior uso dessas ligninas de acordo com suas características. Os três métodos foram Organossolv utilizando uma mistura de dioxano e ácido clorídrico, Organossolv utilizando etanol e o Álcali. A caracterização das ligninas extraídas foi realizada através de técnicas de análise térmica (TG-DTG/DTA), microscopia eletrônica de varredura com aplicação de campo (MEV-FEG), espectroscopia de infravermelho (FTIR), e ressonância magnética nuclear (RMN). Através dos resultados obtidos nas análises evidenciou-se uma alteração maior na lignina extraída pelo método Álcali, com maiores rupturas nas ligações aromáticas durante o processo de extração quando comparado com as ligninas obtidas pelos dois métodos Organossolv. As três ligninas contêm estruturas carbônicas diferentes entre si, sendo que a que mais se aproxima da lignina de origem é a obtida pelo método Organossolv com dioxano.
Brazil is the huge producer of sugarcane worldwide, and it is also the largest residual biomass generator - bagasse and straw. A large part of this biomass is used for energy co-generation, being burnt in the boilers of the plants, but there is still a huge surplus, generating environmental and social problems. So it is necessary to develop projects to use this material with aggregate value. One way is the use of compounds that make up the fiber of bagasse: cellulose, hemicellulose and lignin. To enable the use of these compounds are required little harmful techniques and low cost. Moreover, it’s important that during the extraction process there is little structural change of the compounds or that suffered changes are beneficial for later use. This study aimed to develop different methods of extracting a fraction of this fiber, the lignin, evaluating the changes done by the extraction processes for later use these lignins according to their characteristics. The three methods were Organossolv using a mixture of dioxane and hydrochloric acid, Organossolv using ethanol and Alkali. The characterization of the extracted lignins was performed by thermal analysis techniques (TG-DTG / DTA), scanning electron microscopy with field application (SEM-FEG), infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The results obtained in the analysis revealed a greater change in the lignin extracted by the alkali method with larger breaks in aromatic bonds during the extraction process compared with the lignins obtained by the two methods Organossolv. The three lignins contain carbonic structures different from each other, and that is closest to the origin of lignin is obtained by Organossolv method with dioxane.
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Jesus, Paulo Cesar de. "Enzimas imobilizadas em crisotila e organogel : aplicação na resolução de acidos racemicos." reponame:Repositório Institucional da UFSC, 1998. http://repositorio.ufsc.br/xmlui/handle/123456789/77620.
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Tese (Doutorado) - Universidade Federal de Santa Catarina, Centro de Ciencias Fisicas e MatematicasMade available in DSpace on 2012-10-17T05:56:10Z (GMT). No. of bitstreams: 0Bitstream added on 2016-01-09T00:54:56Z : No. of bitstreams: 1 148818.pdf: 22345368 bytes, checksum: c956fdd898ca38171d6e759c50053878 (MD5)
Neste trabalho dois suportes diferentes foram avaliados para a imobilização de enzimas: o organo-gel contendo lipase de Chromobacterium viscosum (CVL), e a crisotila contendo a lipase de Candida cilindracea (CCL). Estes dois sistemas foram aplicados na resolução dos ácidos carboxílicos racêmicos (±)-2-metil-alcanóicos, (±)-3-metilpentanóico, (±)-2-etil-hexanóico, (±)-2-bromo-alcanóicos, (±)-citronélico, (±)-2-(pclorofenoxi)-propiônico, (±)-canforcarboxílico e o D,L-mandélico via esterificação enantiosseletiva com diferentes álcoois alifáticos, a 25'C em hexano. As enzimas demonstraram preferência pelo enantiômero com rotação óptica positiva para os ácidos (±)-2-metil-alcanóicos com excessos enantioméricos dos produtos na faixa de 54-85%. A CCL imobilizada em crisotila demonstrou preferência pelo enantiômero com rotação óptica negativa para o ácido (±)-2-bromo-octanóico com n-pentanol. Ácidos mais complexos como (±)-2-(p-clorofenoxi)-propiônico, (±)-canforcarboxílico e o D,Lmandélico não foi observado reação nos dois sistemas. Na reação do ácido (±)citronélico com n-pentanol foi observado a preferência pelo enantiômero com rotação óptica positiva na formação do éster para a CVL imobilizada em organo-gel, sendo os valores de excesso enantiomérico para o enantiômero não reativo e o produto de 29 e 48%, respectivamente. Com a CCL imobilizada em crisotila foi observado uma baixa formação de éster (3,19%). Estudos da adsorção da CCL em crisotila demonstraram ser este um processo físico. Os resultados obtidos demonstraram que tanto a crisotila bem como o organo-gel podem ser utilizados, com sucesso, como suportes para a imobilização de enzimas com posterior aplicações destes biocatalisadores em diversas reações em meio orgânico.
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Moniz, Patrícia Maria Azevedo. "Processos de fracionamento de resíduos agroindustriais para obtenção de hemiceluloses e lenhina de elevada qualidade para aproveitamento integrado no âmbito de uma biorrefinaria." Doctoral thesis, ISA/UL, 2014. http://hdl.handle.net/10400.5/7816.
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Bergs, Michel [Verfasser]. "Einfluss von Miscanthus-Genotyp und Erntezeit auf Gehalt und Struktur von Lignin aus Organosolv-Verfahren / Michel Bergs." Bonn : Universitäts- und Landesbibliothek Bonn, 2019. http://d-nb.info/1175580562/34.
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Abdou, Alio Maarouf. "Production de bioéthanol à partir d'une biomasse lignocellulosique multi-ressources locale par prétraitement Organosolv et hydrolyse enzymatique." Thesis, Université Clermont Auvergne (2017-2020), 2020. http://www.theses.fr/2020CLFAC061.
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Dans un contexte de transition énergétique et de lutte contre le dérèglement climatique, la production de bioéthanol de 2ème génération est reconnue comme une voie prometteuse pour réduire notre dépendance aux combustibles fossiles. Mon travail de thèse a porté sur l’étude de faisabilité de la production de bioéthanol de 2ème génération à partir d’un substrat végétal de type « déchet bois », constitué de sciure récupérée auprès d’une scierie locale. Cette sciure est un mélange de quatre espèces de bois de types résineux, représentatives des essences locales. L’analyse chimique de ce déchet a montré qu’il contient environ 70% (g/g) de source potentielle de sucres sous forme de cellulose et d’hémicelluloses exploitables pour la production d’éthanol de 2ème génération par voie biochimique qui fait intervenir trois étapes clés : une étape de prétraitement, une d’hydrolyse enzymatique ou chimique, enfin, une étape de fermentation.L’étape de prétraitement choisie dans ce travail repose sur une méthode Organosolv avec chauffage par micro-ondes. Ce procédé utilise un solvant organique pur ou dilué, additionné d’un catalyseur pour éliminer la lignine tout en favorisant la récupération de la cellulose et des hémicelluloses et en limitant la formation d’inhibiteurs. La lignine, coproduit du fractionnement, peut être valorisée par ailleurs. Des paramètres tels que la concentration en acide sulfurique (H2SO4) en qualité de catalyseur, le rapport éthanol/eau dans le solvant d’extraction, la température et la pression de traitement appliquées ont été étudiés pour optimiser le fractionnement du bois, le rendement et la pureté de la cellulose, la récupération de la lignine et l’absence de formation d’inhibiteurs. Pour le prétraitement, les conditions optimales qui ont été obtenues expérimentalement sur la sciure sont les suivantes : un rapport éthanol/eau de 60/40 avec 0,25% de H2SO4 pour une extraction d’une heure à 175 °C. Ces conditions ont permis d’éliminer 50% de la lignine tout en préservant 82 ± 3% de la cellulose initiale avec une pureté de 71 ± 3%. Ensuite, l’hydrolyse enzymatique du substrat prétraité a été conduite dans des conditions optimales par un cocktail d’enzymes Cellic® Ctec2, (Novozymes, Danemark) à 50 °C et sous agitation (180trs/min), ce qui a permis d’atteindre un taux de conversion de la cellulose en glucose de 80% après 12 jours. Enfin, après enrichissement de l’hydrolysat obtenu, la fermentation de celui-ci par une souche de Saccharomyces cerevisiae a conduit à l’obtention d’un rendement de fermentation alcoolique proche de 80% du rendement théorique, ce qui semble cohérent avec l’absence d’inhibiteurs observée durant les différentes étapes.Les simulations de procédé à l’échelle de la bioraffinerie ont montré que 70 088 tonnes/an de biomasse humide pouvaient être converties en 11 400 tonnes/an d’éthanol en minimisant les besoins en eau et en éthanol (respectivement 4,8 litres d’eau par litre d’éthanol et 99% de taux de récupération de l’éthanol), au prix de besoins plus élevés en énergie (respectivement 10,9 and 8,6 kWh/L d’éthanol pour les utilités chaudes et froides) que pour les prétraitements en phase aqueuseIn a context of energy transition and the fight against climate change,2nd generation bioethanol production is recognized as a promising way to reduce our dependence on fossil fuels.The objective of this study is to analyze the feasibility of 2nd generation bioethanol production from a "wood waste" type of wood substrate, consisting of sawdust obtained from a local sawmill. This sawdust is a mixture of four types of softwood species, representative of local species. Chemical analysis of this waste has shown that it contains approximately 70% (g/g) of potential sugar source in the form of cellulose and hemicelluloses exploitable for the production of 2nd generation ethanol by biochemical route, which involves three key stages: a pretreatment stage, an enzymatic or chemical hydrolysis, and finally a fermentation stage. The pretreatment step selected in this work is based on an Organosolv method. This process uses a pure or diluted organic solvent, added with a catalyst to remove lignin while promoting the recovery of cellulose and hemicelluloses and limiting the formation of inhibitors. Lignin as a coproduct of fractionation can be valued elsewhere. Parameters such as the concentration of sulfuric acid (H2SO4) as a catalyst, the ethanol/water ratio in the extraction solvent, the treatment temperature, and the applied pressure were studied to optimize the fractionation of the wood, the yield and the purity of the cellulose, the recovery of the lignin and the absence of formation of inhibitors. For the pretreatment, the optimal conditions obtained experimentally on sawdust are as follows: an ethanol/ water ratio of 60/40 with 0.25% H2SO4 for one hour extraction at 175 °C. These conditions made it possible to eliminate 50% of the lignin while preserving 82 ± 3% of the initial cellulose with a purity of 71 ± 3%. Next, the enzymatic hydrolysis of the pretreated substrate under the optimal conditions by an enzyme cocktail (CellicR© Ctec2, Novozymes, Denmark) at 50 °C with shaking (180 rpm) achieved a conversion of cellulose to glucose of 80% after 12 days. Finally, fermentation of the glucosidic hydrolyzate by a strain of Saccharomyces cerevisiae led to obtaining an alcoholic fermentation yield close to 80% of the theoretical yield, which seems consistent with the absence of inhibiting compounds observed during the fermentation step. Process simulations at the biorefinery scale showed that que 70,088 tons/year of wet biomass could be converted into 11,400 tons/year of ethanol, enhancing water and ethanol savings (4.8 L water per L ethanol, and 99% ethanol recovery, respectively), at the expense of higher energy requitements (10.9 and 8.6 kWh/L ethanol for hot and cold utilities, respectively) than in pretreatments in aqueous phase
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Silva, Ana Paula da. "Avaliação dos processos responsáveis pela emissão do N2O, num organossolo em Manguariba - RJ." Niterói, 2017. https://app.uff.br/riuff/handle/1/4769.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ
O aquecimento global provocado por gases como CO2, N2O e o CH4 resultantes de atividades agrícolas e por solos alagados tem motivado inúmeros estudos em diversos países, procurando quantificar a contribuição de diferentes sistemas na emissão desses gases. Os objetivos desse estudo foram elucidar o mecanismo de produção do gás do efeito estufa, óxido nitroso (N2O) em uma área de floresta secundária baixa localizada em Manguariba - Rio de Janeiro e determinar se estas emissões ocorrem acompanhadas por processos de nitrificação ou desnitrificação. Para que isso fosse possível, foram realizadas quatro campanhas de amostragens seguidas de experimentos de incubação do solo em laboratório e análises químicas deste solo antes e após as incubações. Medidas de variação de pressão em câmaras sob condições controladas de temperatura foram realizadas empregando-se um manômetro tubo em “U” em quatro experimentos e um barômetro/sensor/datalogger em outros dois experimentos. As concentrações de N2O, bem como as de CH4 no solo, foram determinadas antes e após as incubações por cromatografia gasosa. Na primeira campanha de amostragem foram coletadas também amostras de água em um curso de água que pode ser uma fonte de nitrogênio para este solo, pois em época de chuvas a água poluída com esgoto doméstico, deste riacho chega até os pontos de amostragem. Foram determinadas as concentrações de amônio e nitrato em amostras do solo, antes e após incubações, e na água do riacho. Através dos dados gerados pelas análises químicas determinamos as taxas líquidas de nitrificação, mineralização/assimilação ocorridas durante o período de incubação do solo e correlacionamos essas taxas com a produção de óxido nitroso. A nitrificação a uma taxa constante se mostrou dominante no experimento onde houve a maior produção de N2O. Nos demais experimentos a nitrificação permaneceu dominante, porém seguida por desnitrificação em outros dois experimentos, nos quais a produção do gás foi muito pequena e até mesmo nula, indicando a redução do óxido nitroso a N2. A desnitrificação ocorreu de forma dominante em apenas um dos experimentos e possivelmente foi seguida por nitrificação, pois houve uma pequena produção de N2O durante esta incubação.
The global warming caused by greenhouse gases like CO2, CH4 and N2O resulting from agricultural activities and flooded soils has motivated numerous studies in many countries, seeking to quantify the contribution of different systems on greenhouse gas emissions. The objectives of this study were to elucidate the mechanism of production of greenhouse gas, nitrous oxide (N2O) in a secondary forest area located in downtown Manguariba (Rio de Janeiro) and determines if these emissions occur accompanied by processes of nitrification and denitrification. To make this possible, there were four sampling campaigns followed by incubation experiments of soil in the laboratory and chemical analyses of soil before and after incubations. Measures of barometric pressure variation in PVC chambers under controlled temperature were carried out using a variation of a pressure gauge manometer tube into "U" for four incubation experiments and a sensor which measures the pressure variation barometer / sensor / datalogger (Baro Diver) during the third and fourth experiments. N2O concentrations were determined by gas chromatography. In the first year of sampling, samples of water were taken from a tributary of the Rio Guandu, which can be a source of sewage pollution for this soil, because in the rainy season the water in this tributary reaches the sampling points. Chemical analysis was performed for determination of NH4 + and for analysis of nitrate ions. Data generated by the chemical analysis determined the rate of net nitrification, mineralization / assimilation which occurred during the incubation periods and correlated these rates with the production of nitrous oxide. Nitrification at a constant rate proved to be dominant in the experiment where there was a greater production of N2O. In other experiments, however, nitrification remained dominant followed by denitrification in two other experiments, in which gas production was very small and even zero, indicating the reduction of nitrous oxide to N2. Denitrification was very dominant in only one experiment and was followed by nitrification possibly because there was a small N2O production during this incubation. The experiment with the barometer / sensor / datalogger (Baro Diver) was carried out to confirm what would be the dominant process along these incubations. With this sensor we observed nitrification-dominant production of nitrous oxide. There were no correlations between the flow of N2O emitting in situ and flow generated during the incubation periods. We also observed that the effluent water from the Rio Guandu sample showed high concentrations of nitrate and ammonia and can be considered as a source of inorganic N to this soil
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Roque, Ricardo Miguel Nunes. "Hydrolysis of lignocellulosic biomass by a modified organosolv method on a biorefinery perspective : example of Miscanthus χ giganteus." Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/4763/.
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Concerns about climate change and our awareness on energy security have risen during the last decades leading the search for new forms of energy to reduce the world’s dependence on fossil fuels. Bioenergy has been proposed as one route to contribute significantly to meet global energy demand by using renewable sources of energy. The overall objective of this work was to study and optimise a hydrolysis treatment of lignocellulosic biomass but particularly of Miscanthus \(\chi\) giganteus under the biorefinery concept. A modified organosolv method using subcritical water, ethanol and carbon dioxide on a high-pressure batch reactor was proposed and tested for its efficacy on the hydrolysis and fractionation of Miscanthus into its lignocellulose main components, hemicellulose, cellulose and lignin. Temperature (80–200\(^0\)C), reaction time (5–60 min), ethanol concentration (0–70%), carbon dioxide initial pressure (10–55 bar) and load size (2.5–15 g) were the parameters studied and respective ranges. Optimisation models for solubilisation and delignification were obtained and validated using a central composite design based on a response surface methodology. According to both models temperature is the parameter that affects hydrolysis the most obtaining the highest hydrolysis solubilisation and delignification at 200\(^0\)C. On the other side CO2 initial pressure was not significant, what should be further investigated in the future at higher pressures. Reducing sugars quantification obtained a maximum concentration of 2g/10g Miscanthus by DNS assay with an optimal temperature to hydrolyse hemicellulose from 140 to 180\(^0\)C. FTIR analysis of each fraction confirmed a successful separation of the biomass main components with a reduction in the cellulose fibres crystallinity. Temperature was considered the most significant parameter to fractionate biomass with the highest temperature (200 \(^0\)C) being the one that produced a better quality fibres, supernatant and lignin in terms of contamination by the other fractions. However, results also showed that higher temperature tends to oxidise lignin. Fibres analysis by scanning electron microscopy showed that fibre structure was preserved but presented lignin-type globules on their surface indicating lignin reprecipitation.
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Pimenta, Maria Teresa Borges. "\"Utilização de fluidos no estado sub/supercritico na polpação de Eucalyptus grandis e Pinus taeda\"." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/75/75131/tde-18042007-093604/.
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A utilização de dióxido de carbono em condições sub e supercríticas (em associação com co-solventes) em processos de deslignificação/polpação já se encontra descrito na literatura especializada. Esta técnica se beneficia da elevada difusibilidade apresentada por fluidos no estado sub/supercrítico. Quando aplicada em processos de polpação, a utilização destes fluidos nestas condições pode proporcionar vantagens nas etapas de impregnação e de processamento dos efluentes gerados no processo. Visando aplicar o potencial da elevada difusibilidade apresentada pelo dióxido de carbono supercrítico, realizou-se o estudo comparativo do desempenho dos processos kraft, organossolve convencional e supercrítico frente à deslignificação de diferentes espécies (Eucalyptus grandis e Pinus taeda), empregando-se amostras de diferentes dimensões. O processo kraft se mostrou mais eficiente com o emprego de cavacos, enquanto que a utilização de dióxido de carbono supercrítico, com o uso de co-solvente etanol/água (processo SFE), foi mais eficiente com amostras de maiores dimensões (cubos de 3,5 x 3,5 x 4,0cm). Dentro dos intervalos considerados para as variáveis utilizadas nos diferentes processos de polpação, as polpas obtidas pelo processo SFE a partir de amostras de seção quadrada 3,5 x 3,5cm apresentaram maior conteúdo de holocelulose e maior alvura, evidenciando um elevado rendimento livre de lignina. Estudou-se também o uso de acetona/água e de dioxano/água como co-solventes em processos realizados com dióxido de carbono no estado supercrítico. Os resultados obtidos foram comparados com estudos anteriores realizados com álcoois alifáticos e indicaram a maior efetividade do uso de dioxano/água e 1-propanol/água. Foram realizados também estudos empregando amônia como fluido supercrítico no tratamento de cavacos de Pinus taeda, com o intuito de verificar a capacidade nucleofílica da amônia frente às reações de deslignificação. As reações foram realizadas com o uso exclusivo de amônia e na presença de etanol, água e misturas etanol/água como cosolventes. A análise dos resultados obtidos evidenciou a ocorrência pouco significativa de remoção de lignina, com migração desta para a periferia dos cavacos. As ligninas obtidas nos diferentes estudos foram caracterizadas por diferentes técnicas analíticas e não apresentaram diferenças significativas entre as amostras obtidas nos diferentes processos estudados.The utilization of carbon dioxide under sub/supercritical conditions (in association with co-solvents) in delignification/pulping reactions has already been reported in the literature. This technique takes advantage of the high diffusivity presented by fluids at the supercritical state. When applied to pulping processes the utilization of these fluids can lead to advantages mainly in the impregnation and effluent treatment steps. In an attempt to apply the high diffusivity exhibited by supercritical carbon dioxide, this work presents the results obtained in the comparative study of the performance of the kraft, organosolv and supercritical processes in the delignification of different species (Eucalyptus grandis and Pinus taeda), employing samples with different dimensions. The kraft process presented a higher efficiency in the treatment of wood chips while the supercritical carbon dioxide, with ethanol/water as co-solvent, (SFE process) was more efficient in the treatment of high dimension samples (3.5 x 3.5 x 4.0 cm). In the experimental conditions applied in this study, the pulps obtained in the SFE treatment of samples with square section 3.5 x 3.5 cm showed higher holocellulose content and higher brightness which corresponds to high free of lignin pulp yield. It was also studied the utilization of acetone/water and dioxane/water as co-solvents in the carbon dioxide supercritical pulping process. The results were compared with previous studies performed with aliphatic alcohols and indicated a higher efficiency of the dioxane/water and 1-propanol/water mixtures. The utilization of supercritical ammonia in the treatment of Pinus taeda wood chips was also studied in order to verify the nucleophilic capability of this fluid in the delignification reactions. The reactions were performed with ammonia, exclusively, and in the presence of different co-solvents (ethanol, water and ethanol/water mixtures). The results of the delignifications showed the occurrence of low amount of lignin removal, with migration of lignin to the periphery of the wood chips. The lignins isolated from the reactions performed in this work were characterized by different analytical techniques. The results indicated no significant differences among the samples obtained in the different delignification processes.
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Grossert, Kerstin [Verfasser], and Carsten [Akademischer Betreuer] Schmuck. "Vom kleinen Monomer zum Organogel – orthogonal schaltbare metallosupramolekulare Polymere / Kerstin Grossert ; Betreuer: Carsten Schmuck." Duisburg, 2017. http://d-nb.info/1124395636/34.
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Zhang, Jingjing, and 张晶晶. "The anti-cancer properties of cyclometalated gold(III) complexes and organogold(III) supramolecular polymers." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/208171.
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Prompted by the successful clinical application of cisplatin in cancer therapy, worldwide efforts have been devoted to develop new metal-based drugs for anticancer treatment. Gold(III) complexes at first received attention as anti-cancer drug candidates because of their square-planar geometry which resembles that of platinum(II) complexes. Subsequent studies revealed that various gold(III) complexes displayed promising anti-cancer activities with different biological mechanisms. Although some achievements have been obtained in the development of anti-cancer gold(III) complexes, challenges including the improvement of bioavailability, stability and selectivity, elucidation of the action mechanisms, and the development of novel delivery approaches of gold(III) complexes to reduce systematic toxicity, remain to be exploited.
A panel of anti-cancer complexes [AuIII(R-C^N)(L)]n+ (wherein HC^N is 2-phenylpyridine, L is biguanide or biuret) have been identified and described in Chapter 3. Biguanide or biuret have been employed to improve the solubility of the complexes in aqueous solutions. Meanwhile, the lipophilicity could readily be adjusted by varying the R group to obtain a balance between lipophilicity and aqueous solubility. Among the synthesized complexes, the cationic complexes, [AuIII(butyl-C^N)biguanide]Cl (3.1) and [AuIII(C^N)biguanide]Cl (3.2) are soluble in aqueous solutions with solubility over 5 mg/mL. Besides, introduction of butyl groups to 3.1 and [AuIII(butyl-C^N)biuret] (3.3) resulted in higher cellular uptake of gold, which might enhance their cytotoxic activities (IC50 values: 1.5–17 μM) compared with 3.2 and [AuIII(C^N)biuret] (3.4) (IC50 values: 9.4–47.3 μM). Moreover, 3.1 was also found to induce cell cycle arrest in S-phase and endoplasmic reticulum (ER) damage in human cervical epithelial carcinoma (HeLa) cells, and display significant anti-angiogenic activity at its sub-cytotoxic concentrations.
In Chapter 4, a series of gold(III) complexes with dithiocarbamate and 2-phenylpyridine ligands to target deubiquitinases (DUBs), have been designed. These complexes achieved significant inhibition on purified DUBs. Notably, [AuIII(2-(4-nbutylphenyl) pyridyl)(diethyldithiocarbamate)]PF6 (4.1) inhibited both the purified (IC50 values: 46–223 nM) and cell-based DUBs activities with high efficiency. Its interaction with DUB UCHL1 and peptides which are present in several types of DUBs and contain active cysteine residue were confirmed by mass spectrometric analysis. All complexes displayed significant cytotoxicities, and those containing diethyldithiocarbamate ligand displayed specific cytotoxicity on breast cancer cells. Accumulation of a tumor suppressor p53, cell-cycle arrest, and apoptotic cell death were induced in breast cancer cells by 4.1. Besides, 4.1 also showed anti-angiogenic effects. These biological activities might be related with DUBs inhibition.
In Chapter 5, a cytotoxic complex [AuIII(C^N^C)(4-dpt)](CF3SO3) (5.1, HC^N^CH = 2,6-diphenylpyridine; 4-dpt = 2,4-diamino-6-(4-pyridyl)-1,3,5-triazine) has been designed to self-assemble into supramolecular polymers (5.1-SP) in acetonitrile. In physiologically relevant solutions, 5.1-SP displayed a sustained-release property of the anti-angiogenic ligand 4-dpt, and in the presence of glutathione (GSH), [AuIII(C^N^C)-GSH] adduct(s) were also gradually released. The supramolecular polymers 5.1-SP also showed selective cytotoxicity toward cancerous cells, and could act as drug-carriers of other cytotoxic agents to achieve sustained-release behavior.published_or_final_version
Chemistry
Doctoral
Doctor of Philosophy
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Bonam, Sindhu Prabha. "Preparation and Evaluation of Pluronic Lecithin Organogel Containing Ricinoleic acid for Transdermal Drug Delivery." University of Toledo Health Science Campus / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=mco1384437353.
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Constant, Sandra. "De l'extraction de la lignine à sa valorisation." Thesis, Montpellier, Ecole nationale supérieure de chimie, 2012. http://www.theses.fr/2012ENCM0008.
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L'objectif de ce travail de thèse vise à étudier la conversion de la lignine dans des conditions oxydantes hydrothermales, par catalyse hétérogène. La lignine est l'une des principales constituantes des matériaux ligno-cellulosiques. Considérée comme déchet des procédés de valorisation de la cellulose, elle est majoritairement brûlée pour produire de l'énergie. De par sa structure de polymère phénolique, la lignine peut être considérée comme la principale source de noyaux aromatiques. Une méthodologie analytique complexe a, dans un premier temps, été mise en place pour permettre une caractérisation poussée des lignines et produits d'oxydation. Les lignines étudiées ont été extraites à partir de la paille par un procédé organosolv. Le procédé d'extraction influe sur les rendements mais aussi sur les structures et propriétés des différents produits. Les catalyseurs d'oxydation sont des oxydes divisés des métaux de transition, synthétisés par voie alginate. L'oxydation de la vanilline, composé modèle de la lignine, met en évidence des phénomènes d'oligomérisation des produits formés. Lors de l'oxydation des lignines, l'utilisation d'un catalyseur augmente les rendements et modifie les équilibres de dépolymérisation – oligomérisationThe objective of this thesis is to study the conversion of lignin in oxidizing hydrothermal conditions, by heterogeneous catalysis. Lignin is among the main constituents of lignocellulose materials. Being considered like a waste of the cellulose valorization procedures, it is mostly burned to produce the energy. Taking into account its phenolic polymer structure, lignin can be considered as the main source of aromatic rings. Complex analytical methodology has initially been set up to allow a thorough characterization of lignins and oxidation products. Lignins were extracted from the straw by the organosolv procedure. The extraction process affects not only yields but also the structures and properties of products. The oxidation catalysts are transition metal oxides, synthesized by an alginate route. The oxidation of vanillin (lignin's model compound) shows the oligomerization phenomena of obtained products. In the oxidation of lignin, the use of a catalyst increases the yield and modifies the equilibrium of depolymerization - oligomerization
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Mohamed, Ahmed A. "Redox studies on the anti-rheumatoid arthritis gold drugs : Auranofin and Solganol /." Fogler Library, University of Maine, 2000. http://www.library.umaine.edu/theses/pdf/MohamedAA2000.pdf.
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LeBlanc, Daren James. "Thiol complexes of gold(I) : structure and chemistry of the gold based anti-arthritis drugs /." *McMaster only, 1996.
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Zhou, Zhou. "Synthèse et études structurales de nouveaux [α/aza]-oligomères et cyclooligomères, vers de nouveaux foldamères." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0300/document.
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Ce travail décrit la synthèse et l’étude structurale d’oligomères mixtes et de leurs analogues cycliques alternant des résidus acides α aminés et des résidus acides azaaminés. Le premier chapitre concerne la synthèse en solution des 1:1-[α/aza]-oligomères et des 2:1 [α/aza] oligomères obtenus respectivement par oligomérisation par couplage peptidique de l’azadipeptide Boc-azaPhe-Ala-OMe et de l’azatripeptide Boc-Phe-azaPhe-Ala-OMe correctement déprotégés. Pour la première famille en série L, les rendements en dimérisation et en trimérisation sont moyens en raison de la faible nucléophilie du partenaire amine azadipeptidique. Quant aux 2:1 [α/aza]-oligomères de taille variable, ils ont été isolés avec de très bons rendements quelle que soit la nature L et/ou D des résidus acides α aminés de l’azatripeptide. Ce chapitre présente également l’étude conformationnelle de ces oligomères par spectroscopies RMN et IR, par modélisation moléculaire ainsi que dans certains cas par diffraction des RX. L’analyse des 1:1 [α/aza] oligomères a révélé une auto-structuration majoritaire en solution alternant un coude β et un coude γ stabilisés par des liaisons hydrogène intramoléculaires. L’examen des 2:1 [α/aza] oligomères a permis de mettre en évidence, en série homochirale (L), une conformation majoritaire caractérisée par la formation de coudes β stabilisés par un réseau de liaisons hydrogène intramoléculaires. Des repliements, induits par la formation de coudes β et de coudes γ s’imposent en série hétérochirale (DLDL…). Le second chapitre est consacré à la synthèse en solution et à l’étude conformationnelle des analogues cycliques des oligomères présentés dans le premier chapitre. Les 2:1 [α/aza] cyclooligomères sont surtout discutés, leur synthèse par couplage peptidique intramoléculaire étant plus efficace que celle des 1:1-[α/aza]-cyclooligomères. La formation de nanotubes due à l’empilement des 2 :1-[α/aza]-cyclohexamères homochiraux (L) a été mise en évidence à l’état solide par établissement de liaisons hydrogène intermoléculaires puis suggérée en solution. Le pouvoir gélifiant de certains solvants organiques de l’analogue hétérochiral (DLDL) présage également de son auto-structuration en nanotubes discutée uniquement en solution faute de structure à l’état solideThis work describes the synthesis and structural analysis of mixed oligomers and their cyclic analogues containing an alternation of α-acid residues and α-azaamino acids moieties. The first chapter deals with the “in solution” synthesis of 1:1-[α/aza]-oligomers and 2:1 [α/aza] oligomers respectively, obtained by oligomerization of the properly deprotected azadipeptide Boc-Ala-azaPhe-OMe azadipeptide and Boc-Phe-Ala-OMe-azaPhe tripeptide. For the first family series with L aminoacids, yields dimerization and trimerization are moderate due to the low nucleophilicity of the amine azadipeptidic partner. Concerning the 2:1-[α/aza]-oligomers of variable sizes, they were isolated with very good yields whatever the nature L and / or D of the α-aminoacid residues of the azatripeptide. This chapter also presents the conformational study of these oligomers by NMR and IR spectroscopy, molecular modeling and in some cases by X-ray diffraction. Analysis of the 1:1 [α/aza] oligomers reveals mainly an self-assembly in solution with alternation of β- and γ-turns stabilized by intramolecular hydrogen bonds. Examination of the 2:1 [α/aza] oligomers in homochiral series (L) evidenced a main conformation with repetitive β turns. Regarding the heterochiral series (DLDL….), it is an alternation of β- and γ-turns which is observed. The second chapter is devoted to the solution synthesis in solution and conformational study of cyclic analogues oligomers presented in the first chapter. 2: 1-[α/aza]-cyclooligomers are mostly discussed because their synthesis by intramolecular peptide coupling is more effective than the 1:1 [α/aza]-cyclooligomers. The formation of nanotubes due to the stacking of the homochiral (L) 2:1-[α/aza]-cyclohexamers has been shown in the solid state and suggested in solution. Furthermore, in heterochiral series, the gelling properties of some organic solvents suggest a self-assembly in solution
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Formica, Mariño José Nicolás. "Organos de control, A.R.T. y procedimientos en la industria de la construcción." Bachelor's thesis, Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales, 2013. http://hdl.handle.net/11086/785.
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Práctica Supervisada (IC)--FCEFN-UNC, 2013.Aborda el tema de higiene y seguridad en obra, cómo estos se encuadran dentro de la Ley Nacional de Higiene y Seguridad N°19587, su decreto reglamentario 351/79, la Ley Nacional de Riesgos de Trabajo N° 24557 y demás disposiciones legales vigentes
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Abdelkafi, Masmoudi Fatma. "Destruction de l'alfa (Stipa tenacissima) par un procédé organosolve : analyse et caractérisation de la lignine." Paris 6, 2013. http://www.theses.fr/2013PA066001.
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Le travail présenté dans ce mémoire s’inscrit dans le contexte de la valorisation des biopolymères issue de l’Alfa (Stipa tenacissima), plante annuelle largement répandue en Tunisie. Dans la première partie, nous discutons les caractéristiques écologiques, botaniques et chimiques de l’alfa. Nous étudions ensuite sa déstructuration par le procédé organosolve CIMV (Compagnie Industrielle de la Matière Végétale), qui permet de séparer la cellulose et la lignine. Une étude systématique des différents paramètres de la cuisson, du raffinage de la pâte issue de cette cuisson et d’une séquence de blanchiment originale a été effectuée afin d’optimiser ce procédé. La deuxième partie est consacrée à l’étude structurale de la lignine obtenue par différentes méthodes spectroscopiques, dont la RMN 2D, et à la quantification de la teneur en groupes hydroxyles aliphatiques, phénoliques et carboxyliques par RMN 31P. Les essais de modification chimique de la lignine de paille de blé, ayant une structure très proche de la lignine d’alfa, ont été concluants et permettent désormais d’envisager l’élaboration de nouveaux matériaux polymères à base de lignineThe work reported in this thesis was carried out in the context of biopolymer recovery from Alfa (Stipa tenacissima), a widespread annual plant in Tunisia. In the first part, the ecological, botanical and chemical characteristics of Alfa grass are discussed. The treatment of this vegetal material by the CIMV (Compagnie Industrielle de la Matière Végétale) pulping process, which separates out cellulose and lignin, is then reported. The experimental conditions were systematically studied in order to optimize pulping and bleaching conditions. The second part of this work was devoted to a comprehensive structural investigation of lignin by various spectroscopic methods, including 2D NMR, and to the quantification of aliphatic, phenolic and carboxylic OH groups by 31P NMR. The chemical modification of CIMV wheat straw lignin, structurally close to Alfa lignin, was successful, meaning that the development of new polymeric materials lignin can now be considered
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Wong, Kar-ho. "Luminescent cyclometalated platinum(II) and gold(III) complexes for molecular recognition and DNA binding studies /." Hong Kong : University of Hong Kong, 1999. http://sunzi.lib.hku.hk/hkuto/record.jsp?B20357874.
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Menana, Zahra. "Étude de faisabilité de la valorisation en bioraffinerie de biomasses issues de phytotechnologies : cas d’une plante hyperaccumulatrice (noccaea caerulescens) et d’un ligneux (salix viminalis)." Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0225/document.
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La phytoremédiation est un concept pour la dépollution et de réhabilitation des sols et/ou de friches industrielles contaminés par des éléments traces métalliques (ETMs), utilisant les végétaux pour absorber ou immobiliser les contaminants en présence des organismes microbiens de la rhizosphère. Cette technique a pour conséquence une production de biomasse plus ou moins contaminée qu’il est nécessaire de traiter et également de valoriser. Cependant, la présence d’ETMs peut être problématique dans une approche de conversion en bioraffinerie. Pour répondre à cette question, deux espèces ont été étudiées : une plante herbacée hyperaccumulatrice (Noccaea caerulescens) et un ligneux (Salix viminalis). Deux prétraitements ont été sélectionnés pour cette étude : les prétraitements par explosion vapeur et organosolv, en appliquant différentes conditions opératoires, afin (1) de suivre la distribution des ETMs au cours du traitement, (2) de purifier la matière lignocellulosique et (3) d’évaluer l’effet des ETMs sur les étapes ultérieures d’hydrolyse enzymatique et de fermentation. Pour le prétraitement organosolv la majeure partie des ETMs est récupérée dans le résidu solide cellulosique alors que par explosion à la vapeur, les ETMs sont extraits en grande partie dans les effluents aqueux du traitement. La présence d’ETMs dans les pâtes cellulosiques et les hydrolysats ne montre pas d’effet significatif sur la cinétique d’hydrolyse enzymatique et de fermentation. Concernant spécifiquement Noccaea caerulescens des teneurs relativement importantes en pectines ont été observées, ce qui ouvre des perspectives intéressantes pour la valorisation de cette plante par la production d’un biopolymère d’intérêt industriel. Finalement, les résultats obtenus montrent qu’il serait possible de combiner réhabilitation des sols et valorisation en bioraffinerie de biomasses issues de phytotechnologies soit pour la production du bioéthanol ou la production de molécules plateformePhytoremediation is a concept for the depollution and rehabilitation of soils and/or industrial wastelands contaminated by metal trace elements (MTEs), using plants to absorb or immobilize contaminants in the presence of microbial organisms in the rhizosphere. This technique results in a more or less contaminated biomass production that must be treated and also recovered. However, the presence of MTEs can be an issue in a biorefinery conversion approach. To address this question, two species were studied: an hyperaccumulator herbaceous plant (Noccaea caerulescens) and a woody plant (Salix viminalis). Two pre-treatments were selected for this study: steam explosion and organosolv pre-treatments, applying different operating conditions, in order to (1) monitor the distribution of MTEs during the process, (2) purify lignocellulosic material and (3) evaluate the effect of MTEs on subsequent enzymatic hydrolysis and fermentation steps. For organosolv pretreatment, most of the MTEs are recovered in the solid cellulosic residue while by steam explosion, MTEs are mostly extracted in the aqueous effluents of the treatment. The presence of MTEs in cellulosic pastes and hydrolysates does not show a significant effect on the kinetics of enzymatic hydrolysis and fermentation. Concerning specifically Noccaea caerulescens, the plant contains relatively high levels of pectins, which opens up interesting prospects for the valorization of this plant through the production of a biopolymer of industrial interest. Finally, the results obtained show that it would be possible to combine soil rehabilitation and biorefinery valorization of biomasses from phytotechnologies for either bioethanol production or the production of platform molecules
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Ciabotti, Elaine Donata [UNESP]. "Atributos microbiológicos, químicos e granulométricos de organossolo e latossolos vermelhos: efeito sazonal e uso do solo." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/100826.
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ciabotti_ed_dr_jabo.pdf: 1124222 bytes, checksum: 7cd087e98c4b0152a9237ec078c8fd40 (MD5)Os Organossolos são reconhecidos por seu alto conteúdo de matéria orgânica (MOS). Os micro-organismos e suas atividades são utilizados como indicadores biológicos da qualidade dos solos. Este trabalho objetivou comparar o Organossolo (H) com os Latossolos Vermelhos (cultivado com milho forrrageiro, LV-c; e de pastagem degradada, LV-p) utilizando-se os atributos microbiológicos, químicos e físicos nas estações verão e inverno. Foram avaliadas as populações de bactérias totais, esporuladas, Gram-negativas, actinobactérias, amônio-oxidantes, nitrito-oxidantes, desnitrificantes e dos fungos totais; as atividades e enzimas relacionadas aos ciclos do C, N e P, as análises químicas como MOS, umidade, carboidratos, proteína total, C orgânico solúvel (COS), P total, P orgânico, P inorgânico, P resina, K+, Ca2+, Mg2+, H+Al e a granulometria dos solos. Também foram calculadas a soma de cátions trocáveis (T), a soma das bases (SB) e o índice de saturação por bases (V%). O delineamento experimental utilizado foi em blocos casualizados segundo esquema fatorial 3x2, sendo três solos e duas estações climáticas. Foi realizada a análise de variância e o teste de Scott-Knott para comparação entre médias e correlação linear simples entre as variáveis. A análise de correlação possibilitou demonstrar o efeito dos atributos químicos e granulométricos sobre as populações e atividades microbianas. As populações de micro-organismos, exceto bactérias amônio-oxidantes e nitrito-oxidantes, foram maiores no Organossolo do que no LV-c ou LV-p. Não houve diferença significativa entre as médias dos números de micro-organismos no LV-c e LV-p, exceto para bactérias esporuladas, amônio-oxidantes, nitrito-oxidantes. A população de bactérias esporuladas, a fração areia fina e grande parte das características químicas...
Histosols are recognized for their high content of organic matter (SOM). Microorganisms and their activities are used as biological indicators of soil quality. This study aimed to compare Histosol (H) with Red Oxisols (cultivated with fodder corn, LV-c, and degraded pasture, LV-p) using the microbiological, chemical and physical attributes in summer and winter seasons. Populations of total bacteria, sporulating bacteria, Gram-negative bacteria, actinobacteria, ammonium-oxidizing, nitrite-oxidizing, denitrifying bacteria and total fungi were evaluated. We analyzed enzyme activities related to the cycles of C, N and P, the chemical analysis such as MOS, moisture, carbohydrates, total protein, soluble organic C (COS), total P, organic/inorganic P, P resin, K+, Ca2+, Mg2+, H+Al and soil particle size. It was also calculated the sum of exchangeable cations (T), the sum of bases (SB) and the index of base saturation (V%). The experimental design was completely randomized 3x2 factorial, in three soils and during two seasons. Analysis of variance and Scott-Knott test were conducted to compare averages and simple linear correlation among variables. Correlation analysis allowed to demonstrate the effect of the chemical and granulometric characteristics on microbial populations and activities. Populations of microorganisms, except ammonium-oxidizing and nitrite-oxidizing bacteria were higher in Histosol than in the LV-c or LV-p. There was no significant difference among the average numbers of micro-organisms in LV-c and LV-p, except for sporulating, ammonium-oxidizing and nitrite-oxidizing bacteria. The population of sporulating bacteria, the fraction of fine sand and a large part of the chemical characteristics (pH, P resin, Ca2+, K+, Mg2+, sum of bases, base saturation, total P and inorganic P) were increased in LV-c as... (Complete abstract click electronic access below)
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Ciabotti, Elaine Donata. "Atributos microbiológicos, químicos e granulométricos de organossolo e latossolos vermelhos : efeito sazonal e uso do solo /." Jaboticabal, 2013. http://hdl.handle.net/11449/100826.
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Orientador: Ely NahasBanca: José Frederico Centurion
Banca: Wanderley José de Melo
Banca: Siu Mui Tsai
Banca: Regina Teresa Rosim Monteiro
Resumo: Os Organossolos são reconhecidos por seu alto conteúdo de matéria orgânica (MOS). Os micro-organismos e suas atividades são utilizados como indicadores biológicos da qualidade dos solos. Este trabalho objetivou comparar o Organossolo (H) com os Latossolos Vermelhos (cultivado com milho forrrageiro, LV-c; e de pastagem degradada, LV-p) utilizando-se os atributos microbiológicos, químicos e físicos nas estações verão e inverno. Foram avaliadas as populações de bactérias totais, esporuladas, Gram-negativas, actinobactérias, amônio-oxidantes, nitrito-oxidantes, desnitrificantes e dos fungos totais; as atividades e enzimas relacionadas aos ciclos do C, N e P, as análises químicas como MOS, umidade, carboidratos, proteína total, C orgânico solúvel (COS), P total, P orgânico, P inorgânico, P resina, K+, Ca2+, Mg2+, H+Al e a granulometria dos solos. Também foram calculadas a soma de cátions trocáveis (T), a soma das bases (SB) e o índice de saturação por bases (V%). O delineamento experimental utilizado foi em blocos casualizados segundo esquema fatorial 3x2, sendo três solos e duas estações climáticas. Foi realizada a análise de variância e o teste de Scott-Knott para comparação entre médias e correlação linear simples entre as variáveis. A análise de correlação possibilitou demonstrar o efeito dos atributos químicos e granulométricos sobre as populações e atividades microbianas. As populações de micro-organismos, exceto bactérias amônio-oxidantes e nitrito-oxidantes, foram maiores no Organossolo do que no LV-c ou LV-p. Não houve diferença significativa entre as médias dos números de micro-organismos no LV-c e LV-p, exceto para bactérias esporuladas, amônio-oxidantes, nitrito-oxidantes. A população de bactérias esporuladas, a fração areia fina e grande parte das características químicas... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Histosols are recognized for their high content of organic matter (SOM). Microorganisms and their activities are used as biological indicators of soil quality. This study aimed to compare Histosol (H) with Red Oxisols (cultivated with fodder corn, LV-c, and degraded pasture, LV-p) using the microbiological, chemical and physical attributes in summer and winter seasons. Populations of total bacteria, sporulating bacteria, Gram-negative bacteria, actinobacteria, ammonium-oxidizing, nitrite-oxidizing, denitrifying bacteria and total fungi were evaluated. We analyzed enzyme activities related to the cycles of C, N and P, the chemical analysis such as MOS, moisture, carbohydrates, total protein, soluble organic C (COS), total P, organic/inorganic P, P resin, K+, Ca2+, Mg2+, H+Al and soil particle size. It was also calculated the sum of exchangeable cations (T), the sum of bases (SB) and the index of base saturation (V%). The experimental design was completely randomized 3x2 factorial, in three soils and during two seasons. Analysis of variance and Scott-Knott test were conducted to compare averages and simple linear correlation among variables. Correlation analysis allowed to demonstrate the effect of the chemical and granulometric characteristics on microbial populations and activities. Populations of microorganisms, except ammonium-oxidizing and nitrite-oxidizing bacteria were higher in Histosol than in the LV-c or LV-p. There was no significant difference among the average numbers of micro-organisms in LV-c and LV-p, except for sporulating, ammonium-oxidizing and nitrite-oxidizing bacteria. The population of sporulating bacteria, the fraction of fine sand and a large part of the chemical characteristics (pH, P resin, Ca2+, K+, Mg2+, sum of bases, base saturation, total P and inorganic P) were increased in LV-c as... (Complete abstract click electronic access below)
Doutor
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Guthenberg, Kristoffer. "The impact of the pulping process on the properties of lignin nanoparticles." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278834.
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Lignin valorization is a key component of the total utilization of biomass in the biorefinery industry. Lignin has seen some use in several different applications, but a breakthrough is still yet to happen, and there is still a need to find more areas where lignin can be used as an alternative feedstock or as the main component. Lignin nanoparticles (LNPs) could be an alternative route towards lignin valorization offering many areas of application. However, research around LNPs still has to overcome many challenges, primarily related to the complex structure of lignin, with composition and structure of lignin depending on its botanical origin and on the pulping process used to isolate the lignin from other components in biomass. This study investigates how spruce lignin originating from Kraft and Organosolv pulping will affect the properties of lignin nanoparticles. Particles from organosolv spruce lignin were prepared using a solvent exchange method with acetone/water as solvent and water as antisolvent. This resulted in spherical LNPs with hollow centers, sizes ranging from 104.6- 270.3 depending on initial lignin concentration and average zeta-potential of -35mV. Comparing Organosolv LPN’s with Kraft LNPs produced with the same experimental procedure, reviled that Organosolv LNPs were larger in and had lower absolute zeta potential, presumably due to the kraft lignin having higher phenolic-OH content. Furthermore, a larger comparison is made with LNPs from previous studies which indicated that LNP properties are further dependant Mw of lignin raw material, phenolic-OH content, and the method applied to produce the particles. In conclusion, this study proves that the pulping process used to isolate lining will affect the properties of NPs. But to strengthen and generalize this conclusion beyond the limitations of this study, more experimental data are needed, to further investigate the relationship between LNP properties and the properties of lignin raw material.En av utmaningarna för framtidens bioraffinaderier är att fullständigt utnyttja samtliga komponenter av råvaran. Historiskt sett har cellulosa varit den mest värdefulla komponenten av biomassan medan lignin har klassats som en biprodukt och har därför primärt bränts som bränsle vid framställning av pappersmassa. Även om lignin produceras på industriell skala saknas idag värdeskapande applikationsområden där lignin kan utnyttjas ur ett ekonomiskt hållbart perspektiv. Ett alternativ till valorisering av lignin är att använda det som råmaterial för framställande av nanopartiklar , vilket är ett relativ nytt område med stor potential framförallt inom biomedicin. Dock kvarstår en del utmaningar i forskningen runt lignin nanopartiklar. Framförallt relaterat till lignins komplexa och inhomogena struktur, som varierar beroende på botaniskt ursprung och vilken typ av massaframställningsprocess som används för att isolera ligninet från biomassan. Den här studien undersöker hur granlignin från två olika massaframställningsprocesser, Organosolv- och Kraftprocessen, påverkar egenskaper hos NP av lignin. Under den experimentella delen av arbetet framställdes NP från Organosolv granlignin, vilket resulterade i sfäriska och ihåliga partiklar som varierade i storlek mellan 104.5–270.3 nm, beroende på den initiala lignin koncentrationen, samt en genomsnittlig zeta potential kring -35 mV. Egenskaperna hos Organosolv nanopartiklarna som jämfördes med nanopartiklar av Kraflignin som producerats med samma metod. Slutsatsen drogs att organosolv partiklar var större och hade lägre absolut zeta-potential. Vilket troligtvis kan förklaras med den betydligt högre halten av fenoliska-OH enheter i Kraft ligninet. En bredare jämförelse med tidigare studier som producerat olika lignin nanopartiklar visar dessutom att molekylvikten, fenolisk-OH halt och produktionsmetoden, är bidragande faktorer till lignin nanopartiklars egenskaper. Sammanfattnings visar den här studien att den massaframställningsprocess som används för att isolera lignin kommer påverka egenskaperna hos lignin nanopartiklar. Men för att kunna generalisera och stärka slutsatsen krävs dock utökad experimentella, för att vidare undersöka hur lignin nanopartiklars egenskaper beror på egenskaperna hos ligninet som använts för att producera partiklarna.
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Moura, Marigilson Pontes de Siqueira. "Nanocarreadores contendo ftalocianina de cloroalumínio: desenvolvimento, caracterização físico-química e avaliação in vitro da fotocitotoxicidade em melanoma." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/60/60137/tde-15082011-151702/.
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A Terapia Fotodinâmica (TFD) contra o melanoma cutâneo tem encontrado várias limitações devido à interferência de cromóforos endógenos (melanina) na irradiação deste tipo de cancêr de pele. Agentes fotossensibilizantes que absorverem em comprimentos de onda superiores a 650 nm evitam a competição com a melanina (absorção máxima 530 nm). Neste cenário, surge a ftalocianina de cloroalumínio com forte absorção entre 670-680 nm. Entretanto, esta molécula é lipofílica, o que impede sua aplicação na terapêutica. Para superar este problema, esforços têm sido direcionados para o desenvolvimento de sistemas de veiculação de fármacos hidrofóbicos. Portanto, o objetivo deste trabalho foi desenvolver, caracterizar e avaliar o efeito fotodinâmico de ClAlPc encapsulada em nanocápsulas e nanopartículas de organogel. As nanocápsulas contendo ClAlPc foram obtidas pelo método de nanoprecipitação por meio de um planejamento fatorial 23 e as nanopartículas de organogel contendo ClAlPc foram preparadas pela dispersão a quente do organogel em solução aquosa. Ambas as formulações coloidais foram caracterizadas com relação ao diâmetro médio, índice de polidispersão (IPd), potencial zeta, eficiência de encapsulação (E.E.) e estabilidade física. Os ensaios in vitro de toxicidade e fotocitotoxicidade de ClAlPc nanoencapsulada e/ou livre foram realizados sobre as linhagens melanocíticas WM1552C, WM278, WM1617 e B16-F10. O método de nanoprecipitação foi capaz de produzir nanocápsulas em tamanho nanométrico (233,0 nm ±2,00), com uma distribuição de tamanho homogênea e monodispersa (0,309 ±0,0038), bem como potencial zeta significantemente negativo de 29,6 mV (±3,91). A formulação de nanocápsulas apresentou uma boa E.E. de 63,7% para a ClAlPc. O conteúdo de ClAlPc presente nas formulações de nanocápsulas foi determinado pelos métodos analíticos espectrofotométrico e espectrofluorimétrico validados, os quais foram capazes de quantificar a ClAlPc com precisão e exatidão. O estudo de estabilidade física das formulações de nanocápsulas revelou o caráter estável desta formulação por um período de até 12 meses. As nanopartículas de organogel contendo ClAlPc apresentaram diâmetro médio de 282,7 nm (±2,99), IPd de 0,343 (±0,0280) e potencial de superfície de + 49,3 mV (±1,84). A formulação de nanopartículas de organogel apresentou uma E.E.de ClAlPc de 60%. O estudo de estabilidade física também revelou um comportamento estável das nanopartículas de organogel por um período de 6 meses. Os estudos de toxicidade na ausência de luz demonstraram o caráter biocompatível das nanocápsulas desenvolvidas e foi possível comprovar o excelente efeito fototóxico da ClAlPc nanoencapsulada sobre todas as linhagens melanocíticas com combinação de 0,30 µg.mL-1 de ClAlPc nanoencapsulada e doses de luz de 150 ou 500 mJ.cm-2, nestas condições a fração de morte celular foi superior a 90%. Portanto, estes resultados confirmam o potencial de nanocarreadores contendo ClAlPc como sistema de veiculação de compostos hidrofóbicos aplicados à TFD.Photodynamic Therapy (PDT) against melanoma has found several limitations due to interference from endogenous chromophores (melanin) in the irradiation of this skin cancer. Photosensitizer agents which absorb at wavelengths above 650 nm may avoid melanin competition. In this context, the chloroaluminum phthalocyanine is a promissor photosensitizer with strong absorption between 670-680 nm. However, this molecule is lipophilic difficulting its application in therapy. In order to overcome such problem, efforts have focused on development of drug delivery systems containing hydrophobic photosensitizers. Therefore, the aim of this study was to develop, characterize, and evaluate the photodynamic effect of ClAlPc encapsulated into nanocapsules and organogel nanoparticles. The nanocapsules containing ClAlPc were obtained by nanoprecipitation method using a factorial design 23, and organogel nanoparticles containing ClAlPc were prepared hot dispersion of organogel in aqueous solution. Both colloidal formulations were characterized with respect to average diameter, polydispersity index (PdI), zeta potential, encapsulation efficiency (EE), and physical stability. The in vitro tests for toxicity and photocytotoxicity of nanoencapsulated and free ClAlPc were performed on melanocytic cell lines (WM1552C, WM278, WM1617, and B16-F10). The nanoprecipitation method was able to produce nanocapsules with nanometer-size (233.0 nm ± 2.00), PdI of 0.309 (± 0.0038) indicating homogeneous and monodisperse formulations, as well as significantly negative zeta potential of 29.6 mV (± 3.91). The formulation of nanocapsules showed a good EE of 63.7% for ClAlPc. The ClAlPc content present in nanocapsules was determined by validated analytical spectrophotometric and spectrofluorimetric methods, which were reliably able to determine ClAlPc in nanocapsules. The study of physical stability for nanocapsules showed the stable character of this formulation for a period of 12 months. The nanoparticles of organogel containing ClAlPc had an average diameter of 282.7 nm (± 2.99), IPD of 0.343 (± 0.0280), and surface potential of + 49.3 mV (± 1.84). The formulation of organogel nanoparticles showed a ClAlPc EE of 60%. The physical stability study also revealed a behavior stable organogel nanoparticles for a period of 6 months. Toxicity studies in darkness conditions have been confirmed biocompatibility of nanocapsules. Besides that, the excellent photodynamic effect of ClAlPc nanoencapsulated was reached on all melanocytic cell lines using an arrangement of 0.30 g.mL-1 of ClAlPc encapsulated, and light doses of 150 or 500 mJ.cm-2, under these conditions the cell death fraction was more than 90%. Therefore, these results confirm the potential of nanocarriers containing ClAlPc as delivery system for hydrophobic photosensitizers applied to PDT.
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Malicki, Michal. "Electronic and optical properties of hybrid gold - organic dye systems." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31742.
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Thesis (Ph.D)--Chemistry and Biochemistry, Georgia Institute of Technology, 2010.Committee Chair: Marder, Seth; Committee Co-Chair: Perry, Joseph; Committee Member: Dickson, Robert; Committee Member: El-Sayed, Mostafa; Committee Member: Riedo, Elisa. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Andrade, Valléria Matos. "Obtenção de gel PLO contendo rutina para aplicação transdérmica : caracterização, estabilidade e atividade antioxidante." Pós-Graduação em Ciências Farmacêuticas, 2017. http://ri.ufs.br/jspui/handle/riufs/7785.
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Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPqCoordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Rutin is a flavonoid widely reported in the literature for its antioxidant properties, anti-inflammatory, vasoprotective, antithrombogen, among others. However, its low solubility in aqueous media reduces its bioavailability orally and, therefore, transdermal administration proves to be promising. Thus, the present work aimed to obtain, characterize and evaluate an activity and antioxidant activity of a gel. PLO (Pluronic Lecithin Organogel) containing rutin for transdermal administration.The analytical methodology for rutin quantification was developed and validated by high performance liquid chromatography (HPLC). Initially it was evaluated as an influence of the concentration of Polaxamer 407, obtained by the extrusion method with the aid of syringes, in front of the centrifugation test. The formulation that remained stable after the test was characterized by partical size determination, in vitro release study, in vitro skin penetration study, in vitro skin adhesion study. Also assessed for stability for 60 days at varying temperatures and at predetermined times, physico-chemical characteristics such as pH, density, viscosity and spreadability, as well as organoleptic characteristics, were evaluated. The antioxidant activity of the formulation was evaluated by the TRAP and TAR methods, comparing it with a positive control, Trolox. The results demonstrate that a formulation with higher concentration of Polaxamer is more stable and that is why it was characterized. The partical size were perfect for dermal administration. The formulation demonstrated controlled release of the drug after 24 hours, being able to permeate as deeper layers of the skin and to be absorbed into the systemic circulation, in addition to good adhesion to the skin surface. During the accelerated stability study, as formulations stored at low temperature, they underwent small variations in density, viscosity and spreadability relative to those stored at room temperature, while the pH remained stable throughout and favorable for application in skin. However, as observed variations were not sufficient to cause visual signs of instability. As for the antioxidant activity, a formulation showed greater activity in relation to the Trolox control and the free rutin, but it was not able to sustain an activity for a longer time, presenting a lower TAR value than Trolox. Thus, a chosen formulation has been shown capable of promoting a permeation of the rutin by transdermal route in a controlled manner, as well as being stable at an ambient temperature and having more significant antioxidant activity than the free rutin, and is therefore promising to administration of rutin by this route.
A rutina é um flavonoide bastante estudado devido principalmente as suas propriedades antioxidantes, anti-inflamatória, vasoprotetora e antitrombogência. No entanto, sua baixa solubilidade em meio aquoso reduz sua biodisponibilidade por via oral e, portanto, a administração por via transdérmica pode ser uma alternativa promissora. Dessa forma, o presente trabalho teve por objetivo obter, caracterizar e avaliar a estabilidade e a atividade antioxidante de um gel contendo Pluronic Lecithin Organogel (PLO) contendo rutina, para administração pela via transdérmica. A metodologia analítica para quantificação de rutina foi desenvolvida e validada por cromatografia líquida de alta eficiência (CLAE). Inicialmente foi avaliado qual a influência da concentração do Polaxamer 407, obtidos pelo método de extrusão com auxílio de seringas, frente ao teste de centrifugação. A formulação que permaneceu estável após o teste foi caracterizada através da determinação do tamanho de partícula, estudo de liberação, penetração cutânea e adesão à pele, todos in vitro. Foi também avaliada a estabilidade do produto durante 60 dias em variadas temperaturas em tempos pré-determinados, além das análises físico-químicas, como pH, densidade, viscosidade e espalhabilidade, bem como características organolépticas. A atividade antioxidante da formulação foi determinada pelos métodos TRAP e TAR, em comparação com um controle positivo, o Trolox. Os resultados demonstraram que a formulação contendo maior concentração de Polaxamer é mais estável e por isso esta foi caracterizada. O tamanho de partícula encontrado foi 4,33 μm e o sistema se mostrou homogêneo, ideal para administração cutânea. A formulação demonstrou liberação controlada do fármaco após 24 horas, sendo capaz de permear as camadas mais profundas da pele e ser absorvida para circulação sistêmica, além de boa adesão à superfície da pele. Durante o estudo de estabilidade acelerada, as formulações armazenadas em baixa e alta temperatura, sofreram pequenas variações na densidade, na viscosidade e na espalhabilidade, em relação àquelas armazenadas a temperatura ambiente, enquanto que o pH se manteve estável durante todo o tempo e favorável à sua aplicação na pele. Além disso, as variações observadas não foram suficientes para provocar alterações visuais de instabilidade. Quanto à atividade antioxidante, a formulação demonstrou maior atividade em relação ao controle Trolox e à rutina livre, porém de forma não duradoura, apresentando valor de TAR menor que o Trolox. Sendo assim, a formulação escolhida, demonstrou-se capaz de promover a permeação da rutina por via transdérmica de forma controlada, bem como estabilidade a temperatura ambiente e com atividade antioxidante significativa, sendo considerada então promissora a administração da rutina por esta via.
São Cristóvão, SE