One-pot enzymatic resolution/separation of enantiomers using green solvents

Dissertação para obtenção do Grau de Mestre em Biotecnologia

In the context of “green” chemistry and sustainable processes, the main goal of this work is to develop a process that would circumvent the current complications of racemic sec-alcohol separation, using alternative solvents and selective enzymatic resolution. In this work the ability of enzymes to perform the resolution of sec-alcohols to obtain high added-value enantiomers is advantageously exploited in the production of pure chiral compounds. Candida rugosa lipase is capable of selectively converting one of the enantiomers of menthol into a different chemical compound with substantial different properties. Following this enzymatic catalysis, a separation method is used recurring to alternative solvents properties to separate the enantiomer that does not react obtaining a pure chiral compound. The main goals of this research are to finding both a vinyl ester and an acid anhydride capable of reacting selectively with the racemic menthol through catalyzed reaction using Candida rugosa lipase and test independently the acylating agents at various parameters that influence the conversion and enantioselectivity of the process such as temperature, enzyme concentration, parallel chemical reaction and solvent effect. Through this work we were successful in testing these two different chemical compounds obtaining high values for conversion and enantioselectivity. In the case of propionic anhydride we obtained 51% of conversion, 89% and 74% of enantiomeric excess of substrate and product, respectively, at 310.15 K in [Omim][PF6]. In the case of vinyl decanoate, we obtained 44.4% of conversion, 90.7% of enantiomeric excess of substrate, at 310.15 K in [Hmim][PF6].