超声波辐射 KF/K2CO3／γ－ Al2O3催化合成肉桂酸的工艺研究

摘要

Cinnamic acid was prepared by Knoevenagel method with KF/ K 2 CO3 / γ - Al2 O3 as catalyst and benzaldehyde and propanedioic acid as starting materials under assistance of ultrasonic irradiation. IR,1 H NMR and elemental analysis were used to characterize the product. The effects of catalyst dosage,molar ratio of benzaldehyde and propanedioic acid,ultrasonic irradiation power and irradiation time on the yield of cinnamic acid were studied. The results showed that KF/ K2 CO3 / γ - Al2 O3 catalyst displays good catalytic activity under ultrasonic irradiation. The optimal reaction conditions are as follows:for benzaldehyde 20. 4 mL (21. 2 g, 0. 2 mol),n(benzaldehyde)∶ n(propanedioic acid)= 1∶ 1. 10,KF/ K 2 CO3 / γ - Al2 O3 dosage 4. 5 g,ultrasonic irradiation power 120 W,ultrasonic irradiation time 60 min;and the yield of cinnamic acid reaches higher than 95% .%超声波辐射下，以KF／ K 2 CO3／γ－ Al2 O3为催化剂，丙二酸和苯甲醛为原料，经Knoevenagel 法合成肉桂酸。用IR和1 H NMR及元素分析对产物进行了表征。考察了催化剂用量、苯甲醛与丙二酸摩尔比、超声波辐射功率和辐射时间等因素对肉桂酸收率的影响。结果显示，超声波辐射下，KF／ K 2 CO3／γ－ Al2 O3具有良好的催化活性，且较佳反应条件为：苯甲醛用量20.4 mL （21.2 g，0.2 mol），n（苯甲醛）∶ n（丙二酸）＝1∶1.10，KF／ K 2 CO3／γ－ Al2 O3用量4.5 g，超声波辐射功率120 W，超声波辐射时间60 min。在此条件下，肉桂酸的平均收率达到95％以上。