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While considerable progress has been made towards understanding the effect that membrane-based layer-by-layer (LbL) immobilizations have on the activity and stability of enzymatic catalysis, detailed work is required in order to fundamentally quantify and optimize the functionalization and operating conditions that define these properties. This work aims to probe deeper into the nature of transport mechanisms by use of pressure-induced, flow-driven enzymatic catalysis of LbL-functionalized hydrophilized poly(vinyldiene) (PVDF)-poly(acrylic acid) (PAA)-poly(allylamine hydrochloride) (PAH)-glucose oxidase (GOx) membranes. These membranes were coupled in a sealed series following cellulose acetate (CA) membranes for the elimination of product accumulation within the feed-side solution during operation. At pH = 6 and T = 21oC, the enzymatic catalysis of LbL-immobilized GOx from Aspergillus niger performed remarkably well in comparison to the homogeneous-phase catalysis within an analogous aqueous solution. On average, the enzymatic turnover was 0.0123 and 0.0076 mmol/(mg-GOx)(min) for the homogeneous-phase catalysis and the LbL-immobilized catalysis, respectively. Multiple consecutive permeations resulted in replicable observed kinetic results with R2 > 0.95. Permeations taking place over the course of a three week trial period resulted in a retention of >90% normalized activity when membranes were removed when not in use and stored at -20oC, whereas the homogenous-phase kinetics dropped below 90% normalized activity in under one day.

Orientador: Gabriela Alves Macedo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-12T23:26:09Z (GMT). No. of bitstreams: 1 Lopes_DanielleBranta_M.pdf: 1927712 bytes, checksum: 4c84529dc29400d6dfb671ad68c0abc8 (MD5) Previous issue date: 2009 / Resumo: O aumento da demanda por esteres obtidos naturalmente ou por processos biotecnologicos, para aplicacoes como aditivos em alimentos, cosmeticos, industrias farmaceuticas e de lubrificantes, faz necessario o desenvolvimento de catalisadores altamente especificos. Por esta razao, o uso de enzimas como catalisadores para a sintese de esteres de alto valor agregado vem sofrendo um rapido desenvolvimento, por proporcionar a possibilidade de obtencao de um produto atraves de um processo biologico. Embora destinada pela natureza para realizar a hidrolise de lipideos, lipases (E.C. 3.1.1.3) podem, sob condicoes apropriadas de reacao, promover a formacao de esteres atraves de reacoes de acidos e álcoois (esterificacao). Comparadas com processos quimicos ja realizados em uma escala industrial, reacoes enzimaticas ocorrem sob condicoes brandas (e ecologicamente mais favoraveis) apesar de poderem ser mais lentas. A grande vantagem e a especificidade apresentada pelas enzimas, que permite a formacao de derivados lipidicos, os quais nao sao facilmente preparados por processos laboratoriais convencionais. Neste trabalho, foi avaliado o desempenho de lipases microbianas e vegetais, nao-comerciais, e comparadas a uma lipase comercial, na síntese de esteres com possiveis propriedades emulsificantes, bem como a influencia das condicoes de reacao (concentracao de enzima, quantidade de agua, relacao molar dos substratos, tipos de meios reacionais, e cinetica) no processo de esterificacao. A etapa seguinte do estudo foi constituida de um planejamento experimental fatorial completo com o proposito de otimizar a producao do ester oleato de oleila, em meio livre de solvente organico, com a lipase de Rhizopus sp. selecionada por apresentar melhor desempenho catalitico. O mesmo estudo foi realizado tambem com a lipase comercial Lipozyme TL IMR, com finalidade comparativa. Os parametros reacionais estudados foram: razao molar entre os substratos (acido:alcool) e concentracao de enzima (% m/m em relacao a massa de reagentes). Destes ensaios, verificou-se melhor habilidade catalitica da lipase de Rhizopus sp. utilizando maior proporcao de alcool (2:1) e maior quantidade de enzima (9,8%). O mesmo foi observado com a enzima comercial Lipozyme TL IMR, a qual tambem apresentou maior producao de ester quando se fez uso de uma maior proporcao de alcool (3:1) e maior quantidade de enzima (7,0%). A porcentagem de esterificacao obtida pela lipase de Rhizopus sp. (93,1%) foi muito proxima a porcentagem obtida pela lipase comercial Lipozyme TL IMR (94,2%), evidenciando o grande potencial desta enzima nao-comercial na sintese do oleato de oleila. Por fim, foi realizada a caracterizacao parcial do ester quanto as atividades emulsificante e antimicrobiana. Resultados indicaram que o ester produzido neste trabalho demonstrou atividade emulsificante, porem esta nao foi tao alta quando comparada aos emulsificantes comerciais: Dodecil Sulfato de Sodio (SDS) e Tween 80. Observou-se tambem que o oleato de oleila nao foi capaz de inibir o crescimento microbiano de Bacillus subtilis, sendo assim, ate o presente momento, nao foi detectada atividade antimicrobiana para este ester / Abstract: The increasing demand for esters obtained either through natural or biotechnological processes for use as food additives, cosmetics, pharmaceuticals and lubricants requires the development of highly specific catalysts for ester production. For this reason, the use of enzymes as catalysts for the synthesis of esters with high added value is undergoing rapid development. Although the main function of lipases in nature is to catalyze the hydrolysis of lipids, it can also be made to promote ester formation through the reaction of acids and alcohols (esterification) under specific reaction conditions. Although on an industrial scale enzymatic reactions may be longer when under milder and ¿greener¿ conditions compared to chemical processes. The great advantage of working with enzymes is their great specificity, which often allows for the preparation of lipid derivatives not easily obtained using conventional laboratory procedures. This work first evaluated a few variables affecting the synthesis of esters and the esterification process, namely the influence of: the use of commercial and non-commercial lipases of vegetable and fungi origin, reaction conditions, enzyme concentration, amount of water, molar ratio of substrates, types of organic solvents and reaction kinetics. In a second step, a complete factorial design was considered in order to optimize ester production in solvent-free systems using Rhizopus sp. lipase and Lipozyme TL IMR which were chosen because of their good performance. The reaction parameters chosen were molar ratio of substrates (acid:alcohol) and enzyme concentration. Lipase from Rhizopus sp. displayed the best catalytic activity at a molar ratio of 1:2 (acid:alcohol) and an enzyme concentration of 9.8%, whereas Lipozyme TL IMR had the best catalytic activity at a molar ratio of 1:3 and enzyme concentration of 7.0%. The rate of the sterification reaction yielded 93.1% using lipase from Rhizopus sp., very close to what it is obtained using commercial Lipozyme TL IMR that is 94.2%. This result shows a high potential for this non-commercial enzyme to be used as a catalyst for the oleyl oleate synthesis. The characterization of the ester included evaluation of emulsifier and antimicrobial activities. Oleyl oleate synthesized in this study proved to have lower emulsifier activity compared to commercial emulsifiers like sodium dodecyl sulfate (SDS) and Tween 80. Also, oleyl oleate did not inhibit the growth of Bacillus subtilis, thus no antimicrobial activity was observed for this substance / Mestrado / Mestre em Ciência de Alimentos

Orientador: Ulf F. Schuchardt / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-09T20:28:05Z (GMT). No. of bitstreams: 1 Sales_HenriqueJorgeSousa_D.pdf: 2216336 bytes, checksum: 8961d924bfe31e720b51411a6194bd10 (MD5) Previous issue date: 2007 / Resumo: Neste trabalho, estudamos a esterificação seletiva química e enzimática para a separação dos esteróis, ácidos resínicos e ácidos graxos do resíduo oleoso de madeira, o Crude Tall Oil (CTO). A reação de esterificação enzimática (Candida antartica, lípase do tipo B) foi otimizada utilizando-se um planejamento fatorial 2. Os fatores estudados foram o tempo de reação (h), a temperatura da reação (°C), o teor de catalisador (%), o teor de metanol (%) e o teor de água (%). Com o aumento da temperatura de 24 para 60 °C observamos uma redução média na taxa de conversão de 26,6 %. O aumento da percentagem de metanol de 5 para 15 % também apresentou um efeito negativo na taxa de conversão de 13,1 %; isso indica uma inativação térmica (com a aumento da temperatura) e uma inativação do sítio ativo da enzima pelo metanol. O aumento da porcentagem de água de 0 para 15 % e do tempo de reação de 6 para 24 h apresentou um aumento de 31,2 e de 8,1 %, respectivamente, para a conversão. A interação entre a água e o metanol apresentou um efeito positivo de 22,5 % sobre a conversão, sendo que a melhor condição foi a de efetuar a reação à baixa temperatura (24 °C) com altos teores de água (10-15%) e metanol (10-15%). A adição do metanol em duas etapas também favoreceu a reação, devido ao efeito de desativação que o metanol tem sobre a enzima. O processo foi implementado em produção, onde 13,7 tons de CTO foram esterificadas em um tanque de 25 m e, após 166 h de reação, o índice de acidez caiu de 153,5 para 57,4 mgKOH/g. Através das análises do teor de ácidos resínicos livres, constatamos a total esterificação dos ácidos graxos presentes no CTO. O catalisador enzimático foi adsorvido em polipropileno e foram produzidos dois catalisadores heterogêneos com 0,2 g/g e 0,5 g/g; a relação 0,2 g/g foi a que apresentou a melhor relação custo-benefício para as reações em batelada. O catalisador heterogêneo foi empacotado em uma coluna, e essa foi utilizada para os experimentos de esterificação contínua. O catalisador se mostrou estável por mais de 50 dias. Comparando a performance do processo enzimático x processo químico, o catalisador enzimático apresentou melhor produtividade e seletividade. O resíduo obtido pelo fracionamento em um evaporador thin film apresentou um alto teor de esteróis livres (1,83%) e esteróis esterificados (22,31%). A fração leve do CTO esterificado foi fracionada em uma coluna de destilação piloto. Com este novo processo, obtivemos ésteres metílicos com alto grau de pureza e isento de contaminação por ácidos resínicos. No processo de purificação por destilação, obtivemos ácidos resínicos com 72,3% de pureza. O processo de esterificação seletiva e de fracionamento do CTO foi patenteado pela Cognis do Brasil. / Abstract: A process for obtaining fatty acid alkyl esters, rosin acids an sterols from Crude Tall Oil was developed. As first process step, a chemical or enzymatic esterification has been proposed. It has been shown that the enzymatic esterification of crude tall oil is technically and economically feasible. A 2 experimental design, to optimize the enzymatic process, was done. The factors studied were; reaction time (h), temperature (°C), catalyst (%), methanol (%) and water (%). Increasing the temperature to 60 °C, the conversion decreased 26.6%. The use of high amount of methanol resulted on a conversion of 13.1%. The increase of reaction time and amount of water improved the conversion in 8.1 % and 31.2 %. The best conditions found were reaction time (24 h), temperature (25 °C), water (10-15 %) and methanol (10-15 %). Dosage of methanol must be used because with higher amount of alcohol occurs deactivation of the enzyme. The laboratorial scale experiments were successfully, transferred to a 25 m pumped reactor in the industrial plant. An acid value reduction from 153.5 to 57.4 in 166 hrs could be achieved. Using an immobilized biocatalyst, 0.2 g/g and 0.5 g/g, experiments in a stirred reactor have been performed. The best results were obtained with the 0.2 g/g catalyst system. The biocatalyst was used for successive batches. A continuous process in a column was successfully performed in laboratorial scale. The column was stable for more then 50 days in continuous operation. We compared the performance of enzymatic and chemical esterification. The enzymatic process has better productivity than the chemical process. The separation of the methyl esters and rosin acids from the sterol borates by thin film distillation produced a pitch with (1.83 %) of free sterols and (22.31 %) of total sterols. The separation of the methyl esters from the rosinic acids by distillation produced a high purity methyl ester free of resinic acids and a resinic acid with 72.3 % of purity. The process consists of five steps: 1- Enzymatic and chemical esterification of the tall oil fatty acids with methanol to convert the TOFA in methyl esters; 2- Stripping of water/methanol; 3- Esterification of the free sterols with boric acid. 4- Separation of the methyl esters and rosinic acids from the sterol borates by distillation and 5- Separation of the methyl esters from the rosinic acids by distillation. The process was patented by Cognis Brasil. / Doutorado / Quimica Organica / Doutor em Ciências

Nos últimos anos, a impressão 3D vem se colocando como uma técnica fundamental na produção de novos biomateriais; a estereolitografia, em particular, permite que sejam impressos arcabouços para suporte celular de arquiteturas altamente complexas. Observa-se, todavia, uma oferta pouco significante de resinas passíveis de impressão, uma vez que o mesmo material deve reunir características como biocompatibilidade, biodegradabilidade e, em algumas técnicas de impressão, potencial fotocurável. Este trabalho concentrou-se em sintetizar poliésteres inéditos - derivados de pantenol - biodegradáveis e bioabsorvíveis via policondensação catalisada pela lipase B da Candida antarctica. Além disso, pretendeu-se incluir insaturações de modo a permitir fotorreticulação dos mesmos. Foram produzidos dois tipos de poliésteres insaturados: (1) com insaturações endo (pertencentes à cadeia principal do polímero), a partir de copolímeros produzidos de pantenol e mistura de diésteres saturados (adipato de dietila e sebacato de dietila) e diésteres insaturados (fumarato de dietila e glutaconato de dietila); (2) com insaturações exo (pertencentes às cadeias secundárias do polímero), a partir da acrilação da hidroxila secundária de pantenol de poliésteres saturados do mesmo. A caracterização por cromatografia de permeação em gel mostrou a produção de7 polímeros na faixa de massa molar entre 2000 e 5000 Da. Todas as estruturas foram confirmadas por 1H RMN. A fotocura do material foi testada a partir de soluções dos poliésteres contendo fotoiniciador (BAPO) e correticulantes (NIPAM, NVPM e VIM). Após irradiação com radiação UV em 254 nm por diferentes tempos, foram produzidos filmes que puderam ter sua fração sol/gel determinadas, bem como suas características de intumescimento. Além de serem os primeiros poliésteres de pantenol observados até o momento na literatura, os materiais sintetizados neste trabalho provaram potencial de uso em impressoras 3D, visto que foram produzidos filmes fotorreticulados após cerca de 1 minuto de irradiação. / This work focused on synthesizing unpublished biodegradable and bioabsorbable panthenol-derived polyesters via polycondensation catalyzed by Candida antarctica lipase B. In addition, it was intended to include unsaturations to enable photocrosslinking in the final material. Two types of unsaturated polyesters were synthesized: (1) with unsaturations \"endo\" (belonging to the main polymer chain), from copolymers made of panthenol and mixtures of saturated diesters (adipate, diethyl sebacate and diethyl) and unsaturated diesters (diethyl fumarate and diethyl glutaconate); (2) with \"exo\" unsaturations (not in the main polymer chain), from the acrylation of the secondary panthenol hydroxyl group of the first saturated polyester.9 Characterization by gel permeation chromatography showed the production of polymers in the range of molar mass between 2000 and 5000 Da. All structures were confirmed by 1 H NMR. The photocrosslinking capability of the material was tested from polyester solutions containing photoinitiator (BAPO) and crosslinkers (NIPAM, NVPM, and VIM). After irradiation with UV radiation at 254 nm for different times, films were produced that could have their sol / gel fraction determined, as well as their swelling characteristics. In addition to being the first panthenol polyesters observed so far in the literature, the materials synthesized in this work proved potential use in 3D printers since photocrosslinked films were produced after about 1 minute of irradiation.

This thesis centres on the synthesis of taxol analogues via late-stage hydroxylation with P450 enzymes. To accomplish this, the taxane core, specifically taxa-4(5),11(12)-dien-2-one, was synthesised by classical synthetic methods, and subsequently oxidised using P450_BM3 mutants. Chapter 1 introduces enzymatic catalysis, and the advantages and disadvantages of its application to organic synthesis. Additionally, an overview of taxol, including its discovery, mode of action, biosynthesis and large-scale production, and a summary of the previously reported approaches to the taxane core are described. Chapter 2 details the problems encountered and solutions implemented when reproducing Baran's route to taxa-4(5),11(12)-dien-2-one. Furthermore, approaches to some of its intermediates and an alternative route to taxa-4(5),11(12)-dien-2-one, which is based on Baran's, are discussed. Chapter 3 describes the development of a new, practical and short synthetic route to taxa-4(5),11(12)-dien-2-one which, ultimately, led to 1,3-di-epi-taxa-4(5),11(12)-dien-2-one. Additionally, the application of this route to the synthesis of a model compound and attempts to convert this racemic synthesis into an enantioselective route are reported. Finally, the enzymatic oxidation of taxa-4(5),11(12)-dien-2-one and related molecules using P450_BM3 mutants is explored in Chapter 4. A preliminary study to determine the substrate enantioselectivity of the mutants is also described, along with the biological assays of the oxidised compounds produced during the study.

Efterfrågan på energi ökar snabbt, och denna trend förväntas bestå. Det råder dock ingen tvekan om att världen för närvarande befinner sig i en energikris, som är en katastrof både ekonomiskt och miljömässigt. Följaktligen är sökandet efter alternativa energikällor för att ersätta fossila bränslen absolut nödvändigt. Biobränslen som härrör från biomassa ökar i popularitet på grund av deras höga tillgänglighet och förmåga att minska utsläppen av växthusgaser. Butylbutyrat är ett potentiellt substitut för diesel- och flygmotorbränsle, vilket gör det till en viktig energikälla för både land- och lufttransporter. I den här studien undersöks enzymatisk katalys för produktion av butylbutyrat genom förestring av butanol och smörsyra med hjälp av olika membran. Användningen av enzymer som katalysatorer erbjuder många fördelar jämfört med traditionella kemiska katalysatorer, såsom ökad selektivitet, mildare reaktionsförhållanden och miljövänliga processer. Estrarnas byggstenar, n-butanol och smörsyra, är viktiga kemikalier och kan produceras i biotekniska processer med hjälp av förnybara källor som lignocellulosabaserad biomassa, vilket bidrar till övergången från en petroleumbaserad till en hållbar energiförsörjning. Produktionen av butanol och smörsyra i bioreaktorer försvåras av de typiska hindren för biobränsleproduktion, såsom produkthämning, höga bearbetningskostnader i efterföljande led och låga utbyten. NanoLodge-projektet bygger på tre reaktorer, en för produktion av butanol och en för smörsyra, i två separata men sammankopplade kontinuerliga Clostridium fermenteringar, och ett tredje reaktionssystem för enzymatisk förestring. Alla tre processerna i en, med dedikerade membran som separerar de olika reaktiva systemen, förväntas öka utbytet och samtidigt skapa en mycket integrerad anläggning som kan skalas upp för storskalig drift. Med hjälp av Raman-spektroskopi, GC-FID, FTIR och SEM undersöktes och karakteriserades fem distinkta material och deras relativa membranförändringar, inklusive enzymet på det översta lagret. FTIR-resultaten indikerade att för några av dem var porerna effektivt fuktade med reaktanterna, och membranens hydrofobicitet ökades genom att applicera lämplig beläggning, som även innefattade enzymet. Även om varken syntes av butylbutyrat eller passage genom de olika skikten av membranen inträffade, visade Raman-spektroskopi och GC-FID att et av membranen var en möjlig kandidat för förestring. Dessutom kunde inte alla testade membran motstå reaktionsmediet eftersom SEM-bilder avslöjade att vissa områden av ytan och strukturen hade ändrats något. Mer studier behövs för att fastställa att det med lovande membranet och dess modifieringar, särskilt den hydrofoba naturen och det immobiliserade enzymet, är acceptabla för butylbutyratsyntes. Ytterligare forskning kan utforska processoptimering, enzymimmobiliseringstekniker och reningsmetoder nedströms för att förbättra den totala effektiviteten och ekonomiska bärkraften för denna enzymatiska förestringsprocess.

Ces travaux de thèse portent sur la possibilité de combiner la catalyse hétérogène et la catalyse enzymatique dans une réaction en cascade de transformation de la cellulose en produits d’intérêt. Le prétraitement enzymatique (Celluclast, un cocktail de cellulases) a été choisi comme première étape de transformation de la cellulose en vue de la fragiliser; elle est réalisée dans une solution tampon d’acide acétique et d’acétate de sodium à pH 4,75, à 50°C. Cette étape produit principalement du glucose et modifie structurellement la cellulose résiduelle en diminuant seulement son degré de polymérisation (DP), fournissant de nouvelles extrémités réductrices sans toucher sa cristallinité. L’identification des verrous de la deuxième étape de catalyse hétérogène, réalisée en autoclave à une température supérieure ou égale à 190°C, a consisté à trouver un catalyseur hétérogène qui peut tolérer le milieu réactionnel enzymatique tamponné, qui peut avoir une activité catalytique favorisée sur les celluloses de DP inferieurs et qui peut valoriser le glucose obtenu dans des conditions identiques à la cellulose. Parmi les différentes familles de catalyseurs testés, le catalyseur métallique à base de Pt/charbon, s’est révélé plus efficace que les catalyseurs acides de Lewis et de Brønsted en raison de sa résistance au milieu tamponné et de sa capacité à convertir la cellulose et le glucose dans des conditions identiques malgré l’insensibilité de ce type de catalyseur de la diminution du DP de la cellulose prétraitée. Il a permis de convertir sélectivement la cellulose en propylène et éthylène glycols à 240°C dans une transformation cascade incluant une étape enzymatique suivie d’une étape catalytique hétérogène / This thesis deals with the possibility of combining heterogeneous catalysis and enzymatic catalysis in a cascade reaction for cellulose transformation into value-added products. The enzymatic pretreatment was chosen as the first cellulose transformation step to weaken the cellulose structure which is carried out in a buffer solution of acetic acid and sodium acetate at a pH 4.75, at 50°C. This step is selective, producing mainly glucose, and it has structurally modified the residual cellulose by only decreasing its degree of polymerization (DP) by providing new reducing ends without affecting its crystallinity. The challenges of the second step, heterogeneous catalysis, which is done in a closed autoclave at a temperature greater than or equal to 190°C, were then to find a heterogeneous catalyst that can tolerate the buffered enzyme reaction medium, that can have a favored activity on lower DP celluloses and that can valorize the obtained glucose and cellulose in identical conditions. Among the different families of catalysts tested, the metallic catalyst based on Pt/carbon was shown to be more efficient than the other Lewis and Brønsted acid catalysts due to its resistance to the buffer medium and its abilities to valorize glucose and cellulose in equivalent conditions despite the independence of this type of catalyst to the reduction of the DP of the pretreated cellulose. It allowed to selectively convert cellulose into propylene and ethylene glycols at 240°C in a cascade reaction including an enzymatic catalytic step and a heterogeneously catalyzed one

A DOW é uma empresa que busca continuamente por alternativas para agregar maior valor aos seus produtos através da avaliação das tendências apresentadas pela indústria química. Dentro desta dinâmica, identificou-se uma grande necessidade do mercado de fluidos de corte por inibidores de corrosão mais eficientes e adequados às novas questões regulatórias. Desta avaliação surgiu o tema deste Mestrado Profissional, no qual se estudou a síntese e aplicação de alcanolamidas em fluidos de corte como inibidores de corrosão. Optou-se pela síntese enzimática na ausência de solventes orgânicos por se tratar de uma nova tecnologia à DOW e estar alinhada aos preceitos de sustentabilidades promovidos pela empresa. A escolha pela avaliação das alcanolamidas surgiu de um estudo realizado pela companhia sobre novas tecnologias utilizadas neste segmento e a possibilidade de aplicação destes compostos em outros mercados de atuação da empresa. Foram sintetizadas quatro alcanolamidas, RMEA, RMIPA, RDIPA e RAEPD, obtidas respectivamente da reação entre o ácido ricinoléico e os aminoálcoois: 2-hidroxietilamina, 1-amino-2-propanol, bis-(2-hidroxipropil)amina e 2-amino-2-etil-1,3-propanodiol. O catalisador Novozym 435 (lipase) foi utilizado em todas as sínteses, e estas realizadas de acordo com um planejamento fatorial completo 23. Os produtos sintetizados foram caracterizados por RMN 13C, 1H e dept 135, Espectroscopia no Infravermelho e Espectroscopia de Massas. O rendimento das reações foi mensurado através da técnica de HPLC. Com base nos resultados obtidos foi possível, através do planejamento fatorial, determinar as condições reacionais nas quais o rendimento é maximizado (T = 80 °C; Catalisador = 15 mol/g de ácido ricinoléico; rotação = 600 rpm). A única desvantagem deste processo de síntese foi o custo inerente ao catalisador utilizado. Após o término do planejamento fatorial foram formulados oito fluidos de corte semissintéticos com as alcanolamidas sintetizadas e dois fluidos com o inibidor convencionalmente utilizado. Após verificar a estabilidade térmica destes fluidos, a eficiência à inibição da corrosão foi mensurada através da técnica de manchamento em ferro fundido. Os fluidos contendo as alcanolamidas apresentaram melhor desempenho à inibição da corrosão, porém, não foi possível mensurar quantitativamente as diferenças observadas através desta técnica. Com isso, os compostos foram submetidos a ensaios de perda de massa e polarização potenciodinâmica em ácido clorídrico, além de microscopia atômica para avaliar o efeito dos inibidores na superfície metálica. Através destes estudos foi possível comprovar que os produtos RDIPA e RAEPD possuem maior eficiência à inibição da corrosão. O mecanismo de inibição destes compostos, determinado através de isotermas de Langmuir, ocorre por fisissorção. Após a comprovação das propriedades anticorrosivas dos compostos sintetizados, foram analisadas as seguintes propriedades dos fluidos produzidos: viscosidade, formação de espuma, ângulo de contato, desgaste Reichert, alcalinidade e contaminação microbiológica. Observou-se um aumento da viscosidade e formação de espuma do fluido concentrado. Entretanto, comprovou-se que não há impacto significativo destas propriedades durante a aplicação destes fluidos. As alcanolamidas impactaram positivamente no aumento da lubricidade e reserva alcalina dos fluidos, além de diminuir a taxa de corrosão e a susceptibilidade dos fluidos à contaminação microbiológica, e facilitar o tratamento do resíduo gerado no processo de usinagem devido a maior biodegradabilidade das alcanolamidas. / DOW is a company that continuously searches for alternatives to add greater value to their products through the assessment of trends presented by the chemical industry. Within this dynamic it was identified a great need for more efficient and suitable (to new regulatory issues) corrosion inhibitors applied in metalworking fluids. This Master Thesis came up from this evaluation, where it was studied the synthesis and application of alkanolamides in metalworking fluids as corrosion inhibitors. The enzymatic synthesis in the absence of organic solvents was the chosen production process of alkanolamides because it\'s a new technology to DOW and it\'s aligned with sustainable precepts promoted by the company. The choice for the evaluation of alkanolamides emerged from a study conducted by the company on new technologies applied in metalworking fluids and the possibility of application of these compounds in other markets. It was synthesized four alkanolamides, RMEA, RMIPA, RDIPA and RAEPD, respectively obtained from the reaction between ricinoleic acid and following amino alcohols: 2-hydroxyethylamine, 1-amino-2-propanol, bis(2-hydroxypropyl)amine and 2-amino-2-ethyl-1,3-propanediol. The Novozym 435 catalyst (lipase) was used for all syntheses, and these were carried out according to a full factorial design for three factors. The synthesized products were characterized by NMR 13C, 1H and dept 135, Infrared and Mass Spectroscopy. The yield of the reactions was measured by HPLC technique. Based on the results it was possible, through the factorial design, determine the reaction conditions in which the yield is maximized (T = 80 ° C; Catalyst = 15 mol / g of ricinoleic acid; Speed = 600 rpm). The only disadvantage found of this synthesis process was the cost of the catalyst used. After the factorial design eight semi-synthetic metalworking fluids were formulated with the synthesized alkanolamides and two with the corrosion inhibitor conventionally used. After checking the thermal stability of these fluids, the corrosion inhibition efficiency was measured by staining technique of cast iron. Fluids containing alkanolamides performed better corrosion inhibition, however, was not possible to measure quantitatively the differences observed using this technique. Thus, the compounds were subjected to weight loss and potentiodynamic polarization tests in hydrochloric acid, besides the atomic microscopy to evaluate the effect of the inhibitors on the metal surface. Through these studies it was possible to demonstrate that RDIPA and RAEPD products were more efficient at inhibiting corrosion. The mechanism of inhibition of these compounds, as determined by Langmuir isotherms, is by physisorption. After checking the anticorrosive properties of the synthesized compounds, the following properties were analyzed from the formulated fluids: viscosity, foaming, contact angle, Reichert friction, alkalinity and microbiological contamination. It was observed an increase in viscosity and foaming on the concentrated fluids. However, it was found that there is no significant impact of these properties during the application of these fluids. Alkanolamides enabled an increase in lubricity and alkalinity of the formulated fluids. Additionally they reduced the corrosion rate and the susceptibility of fluids to microbiological contamination, and would make easier the treatment of the waste generated in cutting process due to their higher biodegradability.

Depuis de nombreuses années, l’utilisation d’enzyme pour la synthèse de polymères naturels ou synthétiques a largement été développée en tant que procédé alternatif plus vert et plus respectueux de l’environnement. En effet, comparée aux méthodes conventionnelles de synthèse, les enzymes offrent une sélectivité élevée, une capacité à réagir dans des conditions de réaction douces, ainsi que la possibilité de recyclage du biocatalyseur. D’autre part, les polymères à empreintes moléculaires (MIPs) sont des matériaux synthétiques avec des propriétés de reconnaissance moléculaire spécifique envers une molécule cible. Récemment, les MIPs ont été utilisés dans les applications environnementales et biomédicales de part leur propriétés de reconnaissance moléculaire, leur spécificité et sélectivité. Cependant, leur application reste limitée en raison de leur faible biocompatibilité et de la présence de résidu de polymérisation potentiellement nocif. Ce travail de thèse a pour objectif de proposer une méthode alternative pour la synthèse de MIPs basée sur le concept de chimie verte. La peroxydase de raifort (HRP) est utilisée pour initier la co-polymérisation en milieux aqueux de monomères fonctionnels méthacrylates et d’agents réticulants en catalysant la génération des radicaux libres. Différents hydrogels ont été synthétisés et caractérisés, en particulier une cytotoxicité plus faible a été obtenue comparée à celle des polymères synthétisés traditionnellement. La synthèse a été optimisée afin de pouvoir contrôler la taille des particules et le rendement de polymérisation. Des MIPs sous forme de nanoparticules ont été préparés en milieu aqueux pour plusieurs molécules de faible poids moléculaire ainsi que pour des protéines par polymérisation radicalaire libre initiée par HRP. L’effet de la méthode d’initiation a été évalué en comparant les propriétés de ces MIPs à ceux préparées par les méthodes traditionnellement. L’immobilisation de l’HRP a été aussi effectuée pour synthétiser des hydrogels et des MIPs. L’enzyme immobilisée a pu être réutilisée pour synthétiser des MIPs avec les mêmes performances en termes de morphologie, rendement, spécificité et sélectivité. Ces nouveaux matériaux offrent de nombreuses perspectives pour des applications environnementales et biomédicales. / Enzyme-catalyzed synthesis of natural and synthetic polymers has been developed since several decades, as an eco-friendly process. Compared to the conventional methods, enzymes offer high selectivity, ability to operate under mild conditions and to recycle the catalyst. On the other hand, molecularly imprinted polymers (MIPs) are synthetic materials with specific recognition properties for target molecules. They have recently attracted increasing attention in environmental and newly in biomedical applications for their specificity and selectivity. However, concerns about MIP toxicity for human and environment safety are of great importance. Herein, carrying forward the concept of green chemistry, an enzyme-mediated synthesis approach is described to prepare molecularly imprinted nanoparticles (MIP-NPs) in aqueous media. Horseradish peroxidase (HRP) is used to initiate the polymerization of methacrylate-based monomers and cross-linkers by catalyzing the generation of free radicals. Different hydrogels are synthesized and characterized. “Greener” hydrogels are obtained with lower cytotoxicity than that of polymers synthesized by traditional way. The hydrogels synthesis is optimized in order to control the particles sizes and polymerization yields. Moreover, water-compatible MIP nanoparticles for the recognition of different small molecules and proteins are prepared in aqueous media by HRP-initiated free radical polymerization and compared to MIPs prepared by the thermal or photopolymerization methods. HRP immobilization is also performed for hydrogels synthesis as well as MIP preparation. The reusability of immobilized enzyme is investigated for the preparation of several MIP batches with the same morphology, yield as well as good specificity and selectivity. We believe that this new synthesis method for MIPs will provide new opportunities to enlarge the use of molecular imprinting technology in biomedical and environmental applications.