L'estérification de la cellulose a été réalisée dans deux milieux non-conventionnels. D'un coté, Le CO2 supercritique a permis l'obtention d'esters de cellulose à très faible degré de substitution (DS) en milieu hétérogène. D'un autre coté, les liquides ioniques utilisés ont permis de réaliser l'estérification de la cellulose en milieu homogène et d'obtenir des composés avec un large choix de DS. Parmi ces liquides ioniques, le BMIMCl a conduit à la formation d'ester gras de cellulose à faible DS et avec un caractère thermoplastique innovant. Le deuxième liquide ionique utilisé, découvert grâce à une étude turbidimétrique mise au point lors de ce travail de thèse, a permis d'obtenir des esters gras de cellulose à fort DS dans des conditions opératoires douces. / The esterification of cellulose was performed in two non-conventional media. In one hand, cellulose esters with very low substitution degrees (DS) were synthesized in heterogeneous conditions (supercritical CO2). In an other hand, esterification of cellulose was performed in homogeneous conditions (ionic liquids). In these conditions we obtained cellulose esters with a large range of DS. Among all the ionic liquids used, BMIMCl enable us to synthesize fatty cellulose esters with low DS and with an innovating thermoplastic behavior. Using the second ionic liquid, discovered by a turbiditric study used in this PhD, cellulose esters with high DS were obtained in mild conditions

Orientador: Daniel Barrera-Arellano / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-07-28T11:40:51Z (GMT). No. of bitstreams: 1 Facioli_NaraLucia_D.pdf: 42352647 bytes, checksum: e79cb63c13578f796f470a9771b0cd78 (MD5) Previous issue date: 2001 / Resumo: A esterificação (produção de ésteres metílicos e etílicos) da matéria saponificável do destilado de desodorização do óleo de soja (DDOS) é uma etapa importante para utilização deste resíduo, como matéria-prima, na produção de extratos ou concentrados de tocoferóis (Vit. E) e esteróis. Nesta pesquisa, foram otimizados três processos de esterificação da matéria saponificável do DDOS: 1- esterificação enzimática, utilizando álcool etílico comercial (96%) e Lipozyme'M(uma lipase imobilizada sn-1,3-específica do Mucor miehe/) como catalisador; 2- esterificação química ácida direta, usando álcool etílico anidro e ácido sulfúrico concentrado como catalisador e 3- saponificação/acidulaçãolesterificação com NaOH, H2SO4e álcool etílico. Para otimizar as condições de processo e se obterem as melhores taxas de conversão dos ácidos graxos (AG) em ésteres etílicos, preservando os tocoferóis, foi empregada a Metodologia de Superfície de Resposta, obtida através de um planejamento fatorial de 28 ordem. As condições ótimas de reação encontradas para a esterificação enzimática dos ácidos graxos livres (AGL) do DDOS foram: temperatura de 44 a 56°C; enzima de 12,6 a 17,4% e etanollAGL de 1,5 a 2,5:1, com taxas de conversão acima de 90%. As condições ótimas para a esterificação ácida direta dos AGL do DDOS foram: etanollAGL de 6,5 a 11,2:1, concentração de H2SO4de 0,9 a 1,5% e tempo de reação de 1,3 a 2,6 horas, com taxas de conversão acima de 94%. E para a esterificação dos ácidos graxos totais (AGT) do DDOS, as melhores condições de reação foram: a) saponificação: elação molar NaOH/AGT = 1,5:1, temperatura de 80°C e tempo de reação de 40 minutos; b) a acidulação da mistura foi realizada usando H2S04 com excesso molar de 50% sobre o total de sabões formados e c) as condições ótimas para a esterificação dos AGT foram as mesmas obtidas para a esterificação ácida direta, mas utilizando a variável, relação molar etanollAGT, obtendo-se taxas de conversão acima de 98%. Todas as variáveis estudadas têm efeito significativo sobre a taxa de conversão dos AG (p < 0,05). Os resultados mostraram excelente ajuste entre os modelos matemáticos e os resultados experimentais, nas diferentes condições estudadas, tornando estes modelos preditivos e estatisticamente significativos (p < 0,05). O processo 3 foi considerado o melhor, para esterificação do DDOS. Não foram observadas perdas significativas de tocoferóis durante os processos. / Abstract: The esterification of the soybean oil deodorizer distillate (SODD) saponifiable material is a very important step for the utilization of this residue from the refining oil industry, used as a raw material in tocopherol (Vit. E)and sterol extracts or concentrated production. In this research work, three esterification processes of the SODD unsaponifiable matter were optimized: 1- enzymatic esterification, using commercial ethyl alcohol (96%) and LipozymelM(an immobilized lipase sn-1,3 from Mucor miehel) as the catalyst; 2- direct acid esterification, using anhydrous ethyl alcohol and concentrated sulfuric acid as the catalyst and 3- saponification/acidulation/esterification with NaOH, H2SO4and ethyl alcohol. In order to determine the optima processes conditions to get the higher conversion rates of fatty acid (FA) to ethylic esters, preserving the tocopherols, the response surface methodology (RSM) in a 2nd order factorial planning was utilized to analyze the results. The optima reaction conditions achieved for the enzymatic esterification of SODD free fatty acid (FFA) were: temperature from 44 to 56°C; enzyme concentration from 12.6 to 17.4% and ethanol:FFA molar ratio from 1.5 to 2.5:1, with conversion rates up to 90%. The optima conditions for the direct acid esterification of SODD FFA were: ethanol:FFA from 6.4 to 11.2:1, H2SO4concentration from 0.9 to 1.5% and reaction time from 1.3 to 2.6 h, with conversion rates up to 94%. And for the esterification of total fatty acid (TFA) in SODD the best reaction conditions were: a) saponification: molar ratio NaOHITFA = 1.5/1, temperature of 80°C and reaction time of 40 minutes; b) the acidulation was done using 50% of molar excess H2SO4based on total soaps formed and c) the optima conditions for the esterification of TFA formed were the same for the direct acid esterification, but using the variable, molar relation ethanollTFA, with conversion rates up .to 98%. Ali variables studied had significant effect on the FA conversion (p<0.05). Results showed a good adjustment between mathematical models and experimental results obtained from the different conditions studied, making these models predictive and statistically significant (p<0.05). Process 3 was selected as the best to esterify SODD. No significant tocopherollosses were observed during these processes. / Doutorado / Doutor em Tecnologia de Alimentos

It is the purpose of this investigation to determine the feasibility of using a 120 megacycle oscillometer for kinetic studies in non-aqueous solutions by studying the reaction rate of the base catalyzed esterification of acetic anhydride.

A survey of substitution reactions conducted in a phosphonium bistriflimide ionic liquid is presented. The results demonstrate high selectivity favoring substitution over typically competitive elimination and solvolytic processes even when challenging secondary and tertiary electrophiles are employed. The first reports of Kornblum substitution reactions in an ionic liquid are described that proceed with very high chemoselectivity in favor of nitro over nitroso products and elimination side products. The structure-reactivity study indicates that these reactions proceed through a narrow spectrum of pathways ranging from straight SN2 to a preassociation pathway along a saddle point that approaches the SN1 limit. The lack of any basic entity in the phosphonium bistriflimide ionic liquid appears to prevent any potential base-mediated elimination reactions, which makes this a highly selective medium for use in general substitution reactions. A general, high yielding procedure is described for the esterification of carboxylic acids through carboxylate alkylation in phosphonium salt ionic liquid. The product ester can be readily isolated using a standard extraction protocol or by direct solvent freedistillation allowing ionic liquid re-use. The reaction takes place at relatively low temperature in comparison to other processes reported in ionic liquids. Biologically important BZE (benzoate) esters were synthesized and a proposed solvolysis mechanism investigated in ionic liquids. The Pd-mediated Buchwald-Hartwig amination reaction of aryl halides in phosphonium salt ionic liquid consisting of a trihexyl(tetradecyl)phosphonium cation with a range of anions has been investigated. A pronounced anionic effect was uncovered with the reaction proceeding readily with weakly nucleophilic diarylamines only in the presence of non-coordinating anions. A mechanism is postulated to explain these results involving a rate limiting ligand exchange step that proceeds through a dissociative pathway. A novel non solvated crystal structure of tris(dibenzylideneacetone) palladium(0) in phosphonium salt ionic liquids is reported. This research provided insights concerning the use of ionic liquids in palladium catalyzed Buchwald-Hartwig amination reaction. New synthetic methods were developed for the preparation of trialkyl (methyl) phosphonium ionic liquids, with this novel "green" protocol, the use of iodomethane is eliminated and oxidation of trialkyl phosphines can be reduced. / Thesis / Doctor of Philosophy (PhD)

Photocopy of typescript. / Digitized by Kansas Correctional Industries

The alkoxytriphenylphosphonium ion intermediate of the Mitsunobu reaction for the esterification and inversion of configuration of an alcohol can be generated using the Hendrickson reagent, triphenylphosphonium anhydride trifluoromethanesulfonate, 27. While 27 was used in place of the Mitsunobu reagents (triphenylphosphine and a dialkyl azodicarboxylate) for the esterification of primary alcohols, the reaction failed with secondary alcohols such as (-)-menthol giving predominately elimination rather than the desired SN2 displacement. The difference between the two reactions was shown to be related to the more 'ionic' conditions generated when the Hendrickson reagent 27 was employed. An extreme sensitivity of the Mitsunobu reaction to the presence of salts was discussed and may indicate a mechanism involving ion pair clustering. Five-, six- and seven-membered cyclic analogues of the Hendrickson reagent 90-92 were prepared. A kinetic comparison of the cyclic analogues 90-92 revealed that a considerable increase in the rate of esterification could be achieved when the five-membered ring analogue 90 was used in a non-polar solvent such as toluene. Selected acyclic analogues of the Hendrickson reagent 27 possessing tributyl 118, tricyclohexyl 130 and diphenyl-2-pyridyl 137 functionalities were synthesised. However when 118, 130 and 137 were used for the attempted esterification of (-)-menthol, elimination was the major reaction pathway. Diphenyl-2-pyridylphosphonium anhydride triflate 137 was found to be a useful reagent for the synthesis of acyclic dialkyl ethers from primary alcohols. A polymeric version of the five-membered ring analogue 56, prepared by reaction of the polymer-supported 1,2-bis(diphenylphosphinyl)ethane 57 with triflic anhydride, was used for the preparation of simple esters and amides. A new dehydrating agent, polymer-supported triphenylphosphine ditriflate 157, was readily prepared from the oxidised form of commercially available polymer-supported triphenylphosphine and triflic anhydride. A wide range of dehydration-type reactions, such as ester, amide, anhydride, peptide, ether and nitrile formation, were performed in high yield using polymer-supported triphenylphosphine ditriflate 157. The reagent 157 was easily recovered and re-used several times without loss of efficiency. The use of 4-dimethylaminopyridine allowed the esterification of secondary alcohols with 157 to proceed without elimination and gave esters in high yield but with retention of configuration. Both reagents 56 and 157 provide an alternative to the Mitsunobu reaction, where the use of azodicarboxylates and chromatography to remove the phosphine oxide by-product can be avoided. However, the Mitsunobu reaction retains its supremacy for the inversion of configuration of a secondary alcohol. Preliminary investigations on the phosphityation of alcohols via the Hendrickson reagent 27, 1,3-benzodioxole formation using the Mitsunobu reaction and azodicarboxylate alternatives in the Mitsunobu reaction are described.

Thesis (Ph. D.)--Institute of Paper Chemistry, 1963. / Includes bibliographical references (p. 65-69).

The objective of the research was to carry out the biogeneration of lipophenols by enzymatic esterification of tricaprylin and caprylic acid with catechin and catechol in a model hexane system. Commercial lipases, including Lipase N from Rhizopus niveus, Lipozyme IM from Mucor miehei and Novozym 435 from Candida antarctica were used throughout this study. The effects of reaction time, incubation temperatures and agitation speeds on enzymatic hydrolytic activity were investigated to determine the optimal conditions for biocatalysis. The optimal temperatures for biocatalysis were determined to be 37.5°C for Lipase N, and 55°C for Lipozyme IM and Novozym 435; the optimum agitation speed was 100 rpm. Using Lipase N, maximum hydrolysis of 1.66 mumol free fatty acids/mL was obtained after 1.5 days of incubation, while with Lipozyme IM, maximum hydrolysis of 8.1 and 8.5 mumol free fatty acids/mL was obtained after 1 and 4 days, respectively. With Novozym 435, the highest hydrolysis of 4.0 and 6.1 mumol free fatty acids/mL were found after 2 and 9 days, respectively.

A crescente demanda por lubrificantes obtidos a partir de fontes renováveis vem incentivando a pesquisa por alternativas sustentáveis. O objetivo principal deste trabalho foi investigar a síntese de sebacato de dioctila a partir da reação de esterificação entre o ácido sebácico e o 1-octanol empregando biocatalisadores e catalisador químico convencional (ácido sulfúrico). Alguns parâmetros reacionais foram estudados: tipo de lipase comercial imobilizada (Novozym 435, Lipozyme RM IM e Lipozyme TL IM), temperatura, razão molar ácido/álcool, concentração de lipase, métodos de remoção da água do meio reacional. A reutilização da lipase Novozym 435 também foi avaliada. A conversão da reação foi determinada por cromatografia em fase gasosa. A lipase Novozym 435 apresentou os melhores resultados: 100% de conversão de ácido sebácico quando foi empregada razão molar ácido:álcool de 1:5 e 5% m/m de lipase, após 150 minutos de reação a 100C. O emprego de peneira molecular e vácuo não aumentou a conversão do ácido sebácico. O produto final foi caracterizado com relação à viscosidade, ao índice de viscosidade, ao ponto de fulgor, ao ponto de fluidez e ao índice de neutralização, e apresentou comportamento semelhante a um óleo naftênico / The growing demand for lubricants derived from renewable sources has been encouraging the search for sustainable alternatives. The main objective of this study was to investigate the synthesis of dioctyl sebacate from esterification reaction between sebacic acid and 1-octanol, using biocatalysts and conventional chemical catalyst (sulfuric acid). Some reactions parameters were studied: type of commercial immobilized lipase (Novozym 435, Lipozyme RM IM and Lipozyme TL IM), temperature, molar ratio, lipase concentration, and methods of water removal from the reaction medium. The reuse of lipase Novozym 435 was also evaluated. The conversion of the reaction was determined by gas chromatography. Lipase Novozym 435 showed the best results, achieving 100% conversion of sebacic acid when employing a sebacic acid: 1-octanol molar ratio of 1:5 and 5 wt.% lipase after 150 minutes at 100C. The use of molecular sieve and vacuum did not enhance the acid sebacic conversion. The final product was characterized by viscosity, viscosity index, flash point, pour point and neutralization index; and it showed a pattern similar to a naphthenic oil

Submitted by Janaina Pires Borges null (janaina-pires@hotmail.com) on 2016-02-25T23:51:55Z No. of bitstreams: 1 Produção, imobilização e aplicação de lipase de Fusarium verticillioides -folha de aprovação.pdf: 3325080 bytes, checksum: 8229be49f041bc5bda33de89d9105d13 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-02-29T19:55:35Z (GMT) No. of bitstreams: 1 borges_jp_dr_araiq_par.pdf: 2033105 bytes, checksum: 5e03f09a78c13690ff4b5e81efa828dc (MD5) / Made available in DSpace on 2016-02-29T19:55:35Z (GMT). No. of bitstreams: 1 borges_jp_dr_araiq_par.pdf: 2033105 bytes, checksum: 5e03f09a78c13690ff4b5e81efa828dc (MD5) Previous issue date: 2016-01-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho visou produzir e estudar a lipase do fungo Fusarium verticillioides. A enzima obtida foi avaliada quanto à capacidade de hidrolise, esterificação e transesterificação para a produção de ácidos graxos e ésteres. A cepa fúngica foi cultivada em diferentes meios de cultura, variando as fontes de nitrogênio e de carbono, avaliando-se as atividades. Verificou-se que o tipo de atividade e especificidade da lipase dependem dos nutrientes utilizados nos meios de cultivo do fungo por fermentação em estado sólido. A lipase foi caracterizada físicoquimicamente e apresentou temperatura ótima em 35°C e melhor estabilidade durante 5 horas em 30°C, entretanto a 35°C também foi observada uma boa estabilidade. O pH ótimo foi em 8, e melhor estabilidade em pH ácido (5 e 6). Esta última característica foi muito importante, já que a reação de transesterificação geralmente ocorre em pH 5. A enzima também se mostrou estável na presença de n-hexano e etanol e apresentou uma ativação durante 24 horas diante destes solventes orgânicos. Também foi observada a presença de mais de uma lipase na membrana celular da cepa, o que levou a avaliar sua ação na forma de células imobilizadas diretamente em farelo de trigo e na forma livre. A lipase imobilizada na biomassa fúngica também foi caracterizada, apresentando melhor atuação em pH 8, como ocorreu com a lipase extracelular, porém em 30°C. Por meio de planejamentos fatoriais foi possível observar que a lipase apresenta melhor atividade quando se utilizada ácidos graxos e álcoois de cadeias carbônicas maiores, além de atuar melhor em reações de transesterificação, utilizando-se óleo pré-usado. A célula imobilizada em farelo de trigo foi empregada em hidrólises, sendo obtido 34,9 % de ómega 3 a partir do óleo de canola e 70,9 % de ômega 6 a partir do óleo de linhaça em 12 horas de reação. O extrato bruto de enzimas extracelulares foi submetido à imobilização em suportes inertes. Em octil e fenil-sepharose foi possível imobilizar preferencialmente lipase, sendo verificado por meio da reação de hidrólise do butirato de p-nitrofenila e da quantificação de proteínas totais, com posterior dessorção com triton x 100. O suporte Lewatit 105 mostrou-se ideal para ser utilizado nas reações de esterificação e transesterificação, apresentando boa estabilidade na temperatura ótima da enzima (35°C) e em solução com até 50 % de etanol, também sendo ativado neste meio. Este suporte foi escolhido para aplicação na produção de ésteres etílicos. A enzima extracelular imobilizada e a célula inteira foram aplicadas em reações de esterificação e transesterificação resultando em rendimentos entre 5 e 12 % de ésteres etílicos. / This work aimed to produce and study the lipase from the Fusarium verticillioides fungus. The enzyme obtained was evaluated according to its capacity of hydrolysis, esterification and transesterification to the production of fatty acids and esters. The fungal strain was cultivated in different culture media, varying sources of nitrogen and carbon, evaluating the activities. It was found that the type of activity and the specificity of the lipase depend on the nutrients used in the fungus culture media by fermentation in solid state. The lipase was physically and chemically characterized and presented optimum temperature at 35°C and better stability during 5 hours at 30°C; however, at 35°C it was also observed good stability. The optimum pH was 8 and the stability was better at acid pHs (5 and 6). This last feature was very important, since the transesterification reaction usually happens at pH 5. The enzyme was also stable in the presence of n-hexane and ethanol and presented hyperactivation during 24 hours before these organic solvents. It was also observed the presence of more than one lipase on the cell membrane of the strain, which led to the evaluation of its action in the form of immobilized cells directly in wheat bran and in free form. The lipase immobilized in the fungal biomass was also described presenting better performance at pH 8, as it happened with the extracellular lipase, but at 30°C. Through factorial design, it was possible to observe that the lipase has better activity when fatty acids and alcohols from higher carbon chains are used, besides performing better in transesterification reactions using oils pre-used. The immobilized cell in wheat bran was used in hydrolysis, being 34.9 % of omega 3 obtained from canola oil and 70.9 % of omega 6 from linseed oil in 12 hours of reaction. The extracellular enzyme crude extract was submitted to immobilization in inert carriers. In octyl and phenyl-sepharose, it was possible to immobilize preferably lipase, being it verified through the p-nitrophenyl butyrate hydrolysis reaction and the quantification of total proteins, with subsequent desorption with triton x 100. The Lewatit 105 carrier proved ideal to be used in the esterification and transesterification reactions, presenting good stability at the enzyme optimum temperature (35°C) and in solution with up to 50 % of ethanol, also, being hyper-activated in this medium. This carrier was chosen to be used in the production of ethyl esters. The extracellular immobilized enzyme and the whole cell were used in esterification and transesterification reactions, resulting in returns between 5 and 12 % of ethyl esters.