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对无溶剂体系中阿魏酸的转酯化疏水改性进行了研究,确立了减压反应器(0.001 MPa)中Novozym 435脂肪酶催化阿魏酸乙酯和油醇进行转酯化反应合成新型抗氧化剂阿魏酸油醇酯的方法.发现水活度(aw)明显影响转酯反应,阿魏酸油醇酯产率在aw<0.01-0.75范围内随着水活度的增加而降低,推测底物阿魏酸乙酯和产物阿魏酸油醇酯的水解是该转酯反应的竞争性抑制因素.同时以阿魏酸油醇酯的产率为考察指标,探讨了温度、加酶量、搅拌器转速、反应时间、水活度、底物摩尔比等因素对转酯化反应的影响.确定了脂肪酶催化阿魏酸油醇酯合成的最佳反应条件为:5.0 mmol油醇,1.0 mmol阿魏酸乙酯,70 mg Novozym435脂肪酶,水活度小于0.01,反应温度为60℃,转速为200 r/min,反应时间为96 h,此时阿魏酸油醇酯的产率可达65%.固定化酶反复使用多次后,活性没有明显损失.
The hydrophobic modification of the ferulic acid transesterification in a solvent-free system was studied. It was established that Novozym 435 lipase catalyzed the transesterification of ferulic acid ethyl ester and oleyl alcohol in a vacuum reactor (0.001 MPa) The results showed that the water activity (aw) significantly affected the transesterification reaction. The yield of ferulic acid ferulic acid ester decreased with the increase of water activity in the range of aw <0.01-0.75, It is speculated that the hydrolysis of the substrate ferulic acid ethyl ester and ferulic acid ferulic acid ester is a competitive inhibitor of transesterification.At the same time, Amount, stirrer speed, reaction time, water activity, substrate molar ratio and other factors on the transesterification reaction.The optimum reaction conditions for lipase-catalyzed oleyl ferulate synthesis were determined as follows: 5.0 mmol oleyl alcohol , 1.0 mmol of ferulic acid ethyl ester, 70 mg of Novozym435 lipase, the activity of water is less than 0.01, the reaction temperature is 60 ℃, the rotation speed is 200 r / min and the reaction time is 96 h. Rate up to 65%. After repeated use of immobilized enzyme, no significant loss of activity.