醋酸铵催化合成香豆素-3-羧酸乙酯的工艺研究

以水杨醛和丙二酸二乙酯为原料,醋酸铵为催化剂,采用超声波技术搅拌,在无溶剂条件下,经Knoevenagel缩合反应,合成香豆素-3-羧酸乙酯,其结构经IR表征。考察了超声波辐射时间、原料配比、催化剂的用量等对反应的影响。结果表明,最优条件为：超声波功率100W、超声时间10min、加热反应时间90min、水杨醛与丙二酸二乙酯的物质的量比为1∶1.60、水杨醛与催化剂的物质的量比为1∶1.50。在优化条件下,香豆素-3-羧酸乙酯的收率为89.8%。与常规合成方法相比,该合成方法具有操作简单、收率高、环境友好等特点。

Synthesis of Coumarins-3-ethyl-carboxylate under Ultrasonic Irradiation

The coumarins-3-ethyl-carboxylate was synthesized by Knoevenagel condensation reaction with using salicylaldehyde and diethylmalonate as raw materials and ammonium acetate as catalyst under ultrasonic irradiation without solvent.The product structure was confirmed by IR analysis.The effects of ultrasonic irradiation time,the raw material ratio and the amount of catalyst on reaction were studied.The optimized synthesis conditions were obtained as follows: the ultrasonic irradiation power and time was 100W and 10min respectively,the reaction time was 1.5h,the molar ratio of salicylaldehyde to diethylmalonate was l∶1.60 and the molar ratio of salicylaldehyde to ammonium acetate was 1∶1.50.Under these conditions,the yield of the title compounds was 89.8% with advantages such as simple operation,high yields and environment friendly compared with the traditional methods.