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.

Approche multi-échelle pour l’étude de la réaction de N-acylation enzymatique d’acides aminés La réaction de N-acylation d’acides aminés ou de peptides permet l’obtention de dérivés de ces molécules présentant des propriétés bioactives et/ou techno-fonctionnelles, avec une biodisponibilité, une hydrophobie et une stabilité accrue. Les acides aminés acylés ont été largement décrits comme constituant une classe d'agents tensioactifs avec d'excellentes propriétés de surface, des activités biologiques intéressantes, un faible potentiel de toxicité et un faible impact environnemental. Actuellement réalisée de manière chimique à l’échelle industrielle, l’acylation de ces acides aminés ou peptides présente des contraintes en termes de sélectivité réactionnelle et d’innocuité vis-à-vis de l’environnement ainsi qu’en termes de coût de retraitement des effluents polluants. Une alternative à cette voie chimique est l’utilisation d’enzymes capables de catalyser ces réactions d’acylation. Dans la littérature, différents couples d’enzymes et de solvants ont déjà été décrits. Néanmoins, les performances réactionnelles de ces systèmes demeurent parfois limitées. L’objectif de cette thèse a donc été l’amélioration du procédé d’acylation par une approche à différentes échelles. À l’échelle moléculaire, une étude a été réalisée avec la lipase B de Candida antarctica (CALB). Une approche de modélisation moléculaire a été utilisée afin de mettre au point une méthodologie associant des simulations de docking et des calculs d’interaction permettant d’améliorer la compréhension et permettre la prédiction de la régiosélectivité de CALB lors de l’acylation de la lysine par différents acides gras. Des études ont également été conduites à l’échelle réactionnelle, notamment avec la recherche de nouveaux biocatalyseurs de type aminoacylases dans l’extrait brut de Streptomyces ambofaciens. La régiosélectivité et les performances de la réaction catalysée par ces enzymes ont été comparés à celles de CALB. Les résultats ont mis en évidence un potentiel très prometteur des aminoacylases de S. ambofaciens concernant la synthèse d’acide aminés/peptides acylés. En effet, en plus de leur aptitude à réaliser la réaction d’acylation en milieu aqueux, ces enzymes possèdent une régio-sélectivité qui diffère de celle de CALB. Cette régio-sélectivité orientée vers les groupements N-terminaux est un atout très peu décrit à ce jour, car elle permet d’acyler ces molécules sans modifier les chaînes latérales des acides aminés ou des peptides et donc leurs fonctionnalités. Dans la dernière partie de ces travaux, des études à l’échelle procédé ont été menées. Tout d’abord, l’immobilisation des aminoacylases sur des matériaux mésoporeux silicatés a été réalisée et différentes méthodes d’immobilisation ont pu être comparées. Cette étude a permis de proposer une méthode d’immobilisation des aminoacylases de S. ambofaciens par physisorption, permettant de conserver l’activité spécifique pendant au moins 3 cycles. Puis, dans une dernière partie, l’intensification de la réaction d’acylation en réacteur micro-ondes ou microstructurés a été abordée. Les expérimentations réalisées dans un réacteur chauffé par irradiation micro-onde ont montré que ce type de réacteur était adapté à la réaction d’acylation catalysé par CALB sous sa forme immobilisée commerciale (Novozym435®) en solvant organique, ce qui n’est pas le cas avec des aminoacylases de S. ambofaciens libres, en milieux aqueux. Pour cette réaction, d’autres méthodes d’intensification ont été envisagées, notamment en réacteur microstructuré de type microfluidique. L’efficacité du mélange étant primordiale notamment en milieu biphasique, celle-ci a pu être améliorée avec un taux de conversion supérieur dans ce réacteur comparativement à un réacteur classique agité mécaniquement / N-acylation of amino acids or peptides results in bioactive and/or functional molecules showing increased bioavailability, hydrophobicity and stability. Acylated amino acids have been broadly described as being a kind of surfactant with great surface chemistry properties, interesting biological activities, weak toxicity and low environmental impact. Acylation of amino acids or peptides is being performed chemically at industrial scale. It creates constraints in term of reaction selectivity, environmental safety and cost of polluted wastewater treatment. Enzymatic catalysis is an alternative to chemical acylation reaction. Several enzyme/solvent pairs have already been described in the literature. Their performance are however somewhat limited. The objective of this thesis work was thus to improve the capacity of acylation processes at different scales. At the molecular scale, a study was performed using Candida antarctica’s (CALB) lipase B. Molecular modeling was used to create a methodology coupling docking simulation and interaction calculus that would allow for a better understanding of CALB regioselectivity during lysine acylation by different fatty acids. Studies were also conducted at the reaction level, especially by searching for new aminoacylase-type of biocatalysts in Streptomyces ambofaciens raw extract. Regioselectivity and performance of these enzyme’s catalytic reactions were compared to those of CALB. Results brought into light a promising potential from S. ambofaciens’ aminoacylases in synthesizing acylated amino acids/peptides. Indeed, on top of their ability to catalyse acylation reaction in aqueous solution, these enzymes have a different regioselectivity compared to CALB’s. Regioselectivity targeting N-terminal groups is a rarely researched phenomenon allowing acylation to be performed without modifying amino acids or peptides lateral chains and hence their functionality. In the last part part of this work, studies at process scale were performed. Aminoacylase were first immobilized on mesoporous silicates and several immobilisation methods were compared. Using physisorption, a method for the immobilisation of S. ambofaciens’ aminoacylases was developed to reach a conserved specific activity during 3 cycles. Finally, intensification of acylation reaction was examined in microwave or microstructured reactors. First, an experimental set up was performed in an heated reactor using microwaves irradiation. This kind of reactor was demonstrated as being adapted to acylation reaction using a commercial immobilized form of CALB (Novozym435®) as catalyst in organic solvent. The microwave reactor was however not suited for free S. ambofaciens aminoacylase in aqueous solution. For that latter reaction, intensification had to be approached through other aspects of the process. Hydrodynamic appeared indeed as an important aspect for this reaction occurring in a biphasic medium composed of fatty acids and aqueous solution. A microstructured microfluidic reactor was hence tested. Conversion yield were increased with this system. This study demonstrated how mixing quality was an important factor for acylation reaction and could be a way to intensify the enzymatic process at larger scale

Made available in DSpace on 2017-07-10T17:59:30Z (GMT). No. of bitstreams: 1 Deise Molinari.pdf: 2157738 bytes, checksum: 9e4ace819ec46542bcd06e637a3d604e (MD5) Previous issue date: 2015-03-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Fuels in Brazil have been produced in large scales, creating jobs and promoting economic growth and energy security. Biodiesel is an alternative fuel to petroleum diesel, made from renewable sources such as vegetable oils and animal fats which react with an alcohol in the presence of catalysts. The hidroesterificação is one of the biodiesel production routes and has been much studied, consisting of a hydrolysis step followed by esterification. These reactions when carried out using heterogeneous catalysts, require high temperatures and pressures to occur, which can be circumvented with the use of enzymes as a catalyst, which use milder conditions. The crambe is an oil that has favorable agronomic conditions and a major source of non-edible oil. The use of ultrasound has been shown to be effective in increasing enzyme activity and the formation of microemulsion. This work was comoobjetivo investigate the enzymatic hydrolysis reaction of crambe oil, aiming at the production of free fatty acids, using the Ultra Lecitase lipase (Phospholipase A1), batch reactor with orbital shaking and assisted a batch reactor with cavitaçãoultrassônica gavage. The conversions obtained using the ultrasound probe were lower than those obtained by the batch reactor with orbital shaker. In this study a central rotational design planning compound (CCRD) 2³ full was used to study the effects of varying temperature, fraction of water / oil (W / O) fraction and enzyme / substrate (E / S, where S = weight Total oil and water), the yield of the reaction was followed from acid analysis. The results of the planning for the ultrasound showed that the optimum conditions were met in the study limits. Showing that the use of the ultrasound probe is superior to conventional methods, significantly larger and better formed emulsions. With only 4 hours of reaction the yield of fatty acids was 57.7% at 40 ° C, thus decreasing the reaction kinetics, while the orbital shaker for yield was 65.36%, but 12 hours was required reaction at 50 ° C. Experiments were carried out in optimum condition to obtain the kinetics. A kinetic simplified mathematical model was used to describe reaction kinetics. The use of ultrasound despite providing lower conversion, proved to be a promising technique since it reduces the reaction time. / Os combustíveis no Brasil têm sido produzidos em grandes escalas, gerando empregos e promovendo crescimento econômico e segurança energética. Biodiesel é um combustível alternativo ao diesel de petróleo, feito a partir de fontes renováveis tais como, óleos vegetais e gorduras de origem animal que reagem com um alcool na presença de catalisadores. A hidroesterificação é uma das rotas de produção de biodiesel e que tem sido muito investigada, consistindo em uma etapa de hidrolise seguida de esterificação. Estas reações quando realizadas com catalisadores heterogêneos, necessitam de altas temperaturas e pressões para ocorrer, o que pode ser contornado com o uso de enzimas como catalisador, as quais utilizam condições mais brandas. O crambe é uma oleaginosa que possui condições agronômicas favoráveis e uma considerável fonte de óleo não comestível. O uso de ultrassom tem se mostrado efetivo no aumento da atividade enzimática e na formação de microemulsões. Este trabalho teve comoobjetivo investigar a reação de hidrólise enzimática do óleo de crambe, visando a produção de ácidos graxos livres, empregando a lipase Lecitase Ultra (Fosfolipase A1), em reator batelada com agitação orbital e assistido de um reator batelada com cavitaçãoultrassônica por sonda. As conversões obtidas com o uso do ultrassom de sonda foram inferiores as obtidas pelo reator batelada com agitador orbital. Neste trabalho um planejamento de delineamento central do composto rotacional (DCCR) completo 2³ foi empregado para estudar os efeitos das variáveis temperatura, fração água/óleo (A/O) e fração de enzima/substrato (E/S, onde , S = massa de total de água e óleo), no rendimento da reação que foi acompanhada a partir da análise de acidez. Os resultados do planejamento para o ultrassom mostraram que as condições ótimas foram atingidas nos limites estudados. Mostrando que o uso do ultrassom de sonda é superior aos métodos convencionais, formando emulsões significativamente maiores e melhores. Com apenas 4 horas de reação o rendimento em ácidos graxos foi de 57,7% à 40 ºC, diminuindo assim a cinética reacional, enquanto que para o agitador orbital o rendimento foi de 65,36%, porém, foram necessárias 12 horas de reação à 50 ºC. Foram realizados experimentos na condição ótima para obtenção da cinética. Um modelo matemático cinético simplificado foi utilizado para descrever a cinética reacional. O uso de ultrassom apesar de fornecer menor conversão, se mostrou uma técnica promissora, pois diminui o tempo reacional.

Dans un contexte du développement durable, de nouvelles architectures macromoléculaires biosourcées ont été synthétisées à partir de synthons (diacides et diols) pouvant être obtenus par voies fermentaires à partir de sources carbonées issues de la biomasse. Dans un premier temps, différents copolyesters aliphatiques ont été synthétisés en masse, à l’aide d’un catalyseur organométallique à base de titane, à partir de diacides (acides succinique et adipique) et de diols (1,3-propanediol, 1,4-butanediol et 2,3-butanediol) courts. Dans un deuxième temps, des architectures macromoléculaires similaires ont été obtenues par catalyse enzymatique en solution à l’aide de la lipase B de Candida antarctica. L’influence de la longueur et de la structure des monomères sur leur réactivité en présence de la lipase a été particulièrement étudiée. Dans un troisième et dernier temps, des architectures macromoléculaires à base d’oligomères hydroxytéléchéliques d’un polyester bactérien : le poly((R)-3-hydroxybutyrate) (PHB)tels que des poly(ester-éther-uréthane)s et des copolyesters ont été obtenues soit par couplage de chaîne à l’aide d’un diisocyanate, ou par transestérification organométallique et enzymatique. Ces études ont permis d’analyser en détail l’effet de l’addition des synthons biosourcés dans les architectures macromoléculaires et notamment sur la structure cristalline, la stabilité thermique et les propriétés thermiques et optiques de ces polymères. De plus, le grand potentiel de la catalyse enzymatique pour la synthèse de polyesters et celui de l’utilisation d’oligomères de PHB pour l’élaboration de nouveaux matériaux performants ont pu être largement démontrés. / In the context of sustainable development, new biobased and aliphatic macromolecular architectures were synthesized from building blocks that can be obtained by fermentation routes using carbon sources from the biomass. First, several aliphatic copolyesters were synthesized in bulk from short dicarboxylic acids (such as succinic and adipic acids) and diols (such as 1,3-propanediol, 1,4-butanediol and 2,3-butanediol) by organometallic catalysis using an effective titanium-based catalyst. In a second time, similar macromolecular architectures were synthesized by an enzymatic process in solution using Candida antarctica lipase B as catalyst. The influence of the alkyl chain length and the structure of monomers on their reactivity toward the lipase were particularly discussed. In the third and last part, new macromolecular architectures based on hydroxytelechelic oligomers of a bacterial polyester: poly((R)-3-hydroxybutyrate) (PHB), such as poly(ester-ether-urethane)s and copolyesters, were obtained by either chain-coupling using a diisocyanate, or organometallic and enzymatic transesterification, respectively.These studies permitted to determine a close relationship between the effect of the building blocks structure integrated in the final macromolecular architectures and the intrinsic properties, such as the crystalline structure, the thermal stability and the thermal and optical properties, of these polymers. In addition, the great potential of the lipase-catalyzed synthesis of polyesters and the use of PHB oligomers for developing new high performance materials has been clearly established.

Catalysis is a key area of chemistry. Through catalysis it is possible to achieve better synthetic routes, exploit molecules normally considered to be inactive and also attain novel chemical transformations. The development of new catalysts is crucial to furthering chemistry as a field. Computational chemistry, arising from applying the equations of quantum and classical mechanics to solving chemical problems, offers an essential route to investigating the underlying atomistic detail of catalysis. In this thesis calculations have been applied towards studying a number of different catalytic processes. The processing of renewable chemical sources via homogeneous reactions, specifically cardanol from cashew nuts, is discussed. All routes examined for monoreduction of a diene model by [Ru(H)(iPrOH)(Cl)(C₆H₆)] and [Ru(H)(iPrOH)(C₆H₆)]⁺ are energetically costly and would allow for total reduction of the diene if they were operating. While this accounts for the need of high temperatures, further work is required to elucidate the true mechanism of this small but surprisingly complex system. Gold-mediated protodecarboxylation was examined in tandem with experiment to find the subtle steric and electronic effects that dictate CO₂ extrusion from gold N-heterocyclic carbene activated benzene-derived carboxylic acids. The origin of a switch in the rate limiting step from decarboxylation to protodeauration with less activated substrates was also clearly demonstrated. Studies of gold systems are closed with examinations of 1,2-difluorobenzene C–H activation and CO₂ insertion by [Au(IPr)(OH)]. Calculations highlight that the proposed mechanism for oxazole-derived substrates cannot be extended to 1,2-difluorobenzene and instead a digold complex offers more congruent predicted kinetics. The lens of quantum chemistry was turned upon palladium-mediated methoxycarbonylation reactions. An extensive study was undertaken to attempt to understand the bidentate diphosphine ligand dependency on forming either methylpropanoate (MePro) or copolymers. Mechanisms currently suggested in literature are shown to be incongruous with the formation of MePro by Pd(OAc)₂ and bulky diphosphines. A possible alternative route is proposed in this thesis. Four mechanisms for methoxycarbonylation with Pd(2-PyPPh₂)ₙ are detailed. The most accessible route is found to be congruent with experimental reports of selectivity, acid dependency and slight steric modifications. A modification of 2-PyPPh₂ to 2-(4-NMe₂-6-Me)PyPPh₂ is shown to improve both selectivity and turnover, the latter by four orders of magnitude (highest transition state from 22.9 kcal/mol to 16.7 kcal/mol ∆G), and this new second generation in silico designed ligand is studied for its applicability to wider substrate scope and different solvents. The final chapter of this thesis is a mixed quantum mechanics and molecular mechanics (QM/MM) examination of an enzymatic reaction, discussing the need for certain conditions and the role of particular amino acid residues in an S[sub]N2 hydrolysis reaction.