The ethyl hexanoate was synthesized over the immobilized lipase Candida sp 99-125 in solvent. The effects of solvent, lipase dosage, molar ratio of ethanol to hexanoic acid, concentration of hexanoic acid, reaction temperature and time on the conversion of hexanoic acid were investigated. The results showed that the conversion of hexanoic acid reached 96.0% under the conditions of hexane 5 mL, hexanoic acid 0.3 mol/L, molar ratio of ethanol to hexanoic acid 1.6, silica gel 0.6 g, reaction temperature 40 "C, time 8 h and stirring speed 150 r/min. The catalytic performance of the immobilized lipase was stable and under the above conditions, the conversion of hexanoi acid remained above 75.0% after being used 3 times.%采用实验室自制的脂肪酶Candida sp 99-125在有机溶剂中催化合成乙酸乙酯,考察了有机溶剂种类、加酶量、酸醇物质的量之比、已酸浓度、反应时间和温度等对己酸转化率的影响.结果表明:以5 mL正已烷为溶剂的反应体系中,酶0.123 g,已酸浓度0.3 mol/L,醇酸物质的量之比1.6,硅胶0.6 g,于40℃在转速为150 r/min的摇床中反应8 h,己酸转化率可高达96.0%.在上述条件下,酶使用3次后,己酸转化率仍能达到75.0%以上.
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