Enzyme Catalysis Split 2 - Octanol

As important choral intermediates, optically active alcohols were widely used in the production of pesticide and liquid crystals for their vital useful value, widely interesting have been aroused. The main route for obtaining optically active alcohols is resolution of racemic alcohols catalyzed by enzyme in organic solvents by the esterification reaction. In this thesis, a solvent-free system was developed in resolution of (R, S)-2-octanol catalyzed by the enzyme with ester, and c ester was introduced as an acylating agent, the reaction being irreversible because of the formation of aldehyde[1-4]. And the negative role of solvents and water were effectively eliminated, for the reaction was irreversible. The optimal reaction condition was determined by studying it and 2-octanol of high optics purity was prepared.A great deal of organic solvents were used in the reaction by enzyme catalyzed, it was difficult to remove water from the reaction system; substrates concentration was low in the organic system, and it was not high for the yield of products and the percent recovery of substrates. The solvent-free system was selected. The irreversible transesterification was used to resolve the problem, which was in the esterification that had the defects such as the reaction reversibility, the content of water controlled with the process of reaction. When 2-octanol and c ester were catalyzed by A enzyme, the single configuration of 2-octanol was remained because the (R), (S)-2-octanol had different reaction rate. From the time course of conversion of (R, S)-2-octanol, we have known that. The reaction was stopped after four days, and the products were separated and purified,then 2-octanol with higher optically purification was obtained.Though the studying of the reaction condition, we have found the factors, which are the ratio of molar of substrate, the content enzyme in the system, different sources of enzymes, different acyl donors and the reaction temperature, influenced the effect of resolution of racemic 2-octanol catalyzed by enzymes. The reaction condition was as follows: the substrate was c ester and 2-octanol, which the ratio of molar of substrate was 1.5 to 1, catalyzed by A enzyme. The reaction was in the constant temperature cradle with 170rpm and stopped the reaction after four days.The reaction mixtures were separated and purified under above conditions. Then the products with optically purification were obtained by reduced pressure and contracted methods. The rate of production was 27.28% (the theoretical rate of production is 50%), the purification was 98.91%, and e.e. in the reaction system was 94%.