Lipase-Catalyzed Regioselective Synthesis Of Sucrose-6-Acetate

The enzymatic synthesis of sucrose acetate was performed by transesterification of sucrose and vinyl acetate in organic solvent and buffer-organic solvent systems.The optimal conditions in the two reaction systems were obtained.The affects of reaction solvents on regioselectivity were studied preliminarily.The main contributions were as follows:1、The acylating of sucrose and vinyl acetate was catalyzed by Lipozyme TLIM in Tert-butyl alcohol system.The reaction parameters were studied in detail.Under the optimal condition,the yield of sucrose-acetate reached 84.70%.Sucrose-6-acetate was separated by silica gel column chromatography and identified by 2D-NMR.The yield of sucrose-6-acetate reached 48.30%.2、Using sucrose and vinyl acetate as substrate,catalyzed by Candida rugosa lipase（CRL） in a two-phase C₈H₁₁N₂NaO₃-HCl/Tert- amyl alcohol system with the aim of producing sucrose acetate.The tendency that every parameter influenced on yield was studied.The significant key factors were investigated according to Plackett-Burman design.The optimal values of the variables were determined by Central composite design.Experimental results showed that the yield could reach to 57.42%at optimal conditions,with an increase of 6.65%compared with that before optimization.3、The effect of solvent on regioselectivity of acylation between sucrose and vinyl acetate using Candida rugosa lipase（CRL） was investigated.The initial findings showed that isopropanol/ C₈H₁₁N₂NaO₃-HCl system and Tert-amyl alcohol/Tris-HCl system were better for synthesis 6-acetate.In that two reaction systems,40.08%and 52.42%6-acetate was formed respectively.In the Tert-amyl alcohol/Tris-HCl system it is possible to reaiize on-line separation of the product.