【摘要】 对脂肪酶在离子液体中催化香叶醇与乙酸乙烯酯转酯化反应生成乙酸香叶酯的过程进行了研究.考察了水活度、底物酯和醇物质量的比率、温度、离子液体和酶的重复利用对催化得率及催化反应初始速率的影响,其中离子液体的水活度采用水合盐对进行控制,而在考察离子液体和酶的重复利用时采用了未经分离酶的间歇反应的方法.结果表明,随着水活度增加酶在离子液体1-丁基-3-甲基-咪唑六氟磷酸盐中催化反应的初始速率的变化趋势呈钟形曲线.最优的催化反应条件为:水活度为0.28,底物酯和醇物质量比为9.42,30℃.在重复利用12次后,离子液体体积和酶的催化活力都没有明显减少.更多还原

【Abstract】 Lipase transesterification of vinyl acetate with geraniol in ionic liquid was investigated.Effects of water activity(a_w),the molar ratio of ester to alcohol,temperature,the reuse of ionic liquid and enzyme on the reaction were examined.The water activity in ionic liquid was controlled by salt hydrate pairs.The method of using batch reaction without separating enzyme was adopted in the study on the reuse of ionic liquid and enzyme.The results showed that the dependency of the initial rate on the water activity followed a classical bell-shaped curve.Optimum yield was obtained at molar ratio of 9.24,a_w=0.28,30 ℃ in(ionic) liquid (1-butyl-3-methyl imidazolium hexafluorophosphate).The volume of ionic liquid and catalytic ability of enzyme did not reduce significantly after being reused twelve times.更多还原