固定化酶催化桐油酯交换反应的研究

A Study on Immobilized Lipase Catalyzed Transesterification Reaction of Tung Oil

【目的】本文以桐油为原料,研究固定化脂肪酶催化桐油与甲醇酯交换反应的工艺条件。【方法】Novo435脂肪酶为催化剂,在无有机溶剂存在的情况下,利用响应面研究方法,对桐油酯交换反应的工艺条件进行研究和优化。【结果】得到了桐油酯交换反应的最佳工艺条件:醇油比2.2﹕1、温度43℃、脂肪酶用量14%(与油脂的质量比)、搅拌转速200 r/min,反应18 h后,桐油的酯交换率达到了67.5%(理论为73.3%)。脂肪酶经有机溶剂洗涤后连续使用120 h,桐油酯交换率减小了6%。理论甲醇量不能一次加入,分两批加入,共反应36 h后,桐油的酯交换率达到85%(理论为100%)。【结论】影响桐油酯交换反应的显著因素为醇油比、脂肪酶用量、反应温度和反应时间,各因素间有一定的交互作用。

[Objective] The transesterification reaction conditions of tung oil with methanol with immobilized lipase as catalyst was studied. [Method] Novo435 lipase was the catalyst, and a response surface methodology was used to optimize the transesterification reaction of tung oil in the non-solvent system. [Result] The optimized reaction condition was found： rotation rate was 200 r/min, the molar ratio of methanol to oil was 2.2：1, reaction temperature was 43℃, the catalyst was 14% （based on the weight of oil）, and after reacting for 18 h, 67.5% of the oil was converted to its corresponding methyl esters （the academic conversion is 73.3%）. The lipase was washed by organic solvents after each reaction and reused again, the esters conversion of tung oil was decreased by 6% after the lipase being reused for 120 h. The theoretical amount of methanol was added by two steps, 85% conversion was obtained after 36 h of reaction （theoretical conversion is 100%）. [Conclusion]The molar ratio of methanol to oil, the catalyst amount, the reaction temperature and reaction time were all highly significant factors, and there was a relative significant interaction between every two factors.