KF/K_2CO_3/γ-Al_2O_3催化合成香豆素-3-羧酸

Synthesis of coumarin-3-carboxylic acid catalyzed by KF/K_2CO_3/γ-Al_2O_3

以水杨醛和丙二酸二乙酯为原料,KF/K2CO3/γ-Al2O3为催化剂,催化合成香豆素-3-羧酸乙酯,再经皂化、酸解环合合成香豆素-3-羧酸。考察了催化剂用量、水杨醛与丙二酸二乙酯摩尔比、反应时间等因素对香豆素-3-羧酸收率的影响。结果表明,KF/K2CO3/γ-Al2O3具有良好的催化活性,较佳工艺条件为:水杨醛4.88 g(0.04 mol),n(水杨醛)∶n(丙二酸二乙酯)=1∶1.25,KF/K2CO3/γ-Al2O32.0 g(KF 3.74 mmol),无水乙醇20 mL,反应1.5 h,香豆素-3-羧酸的平均收率达到92%以上。

Ethyl coumarin-3-carboxylate was synthesized by using salicylaldehyde and diethyl malonate as starting materials and KF/K2CO3/γ-Al2O3 as catalyst.The product was further processed by saponification and ring closure acidolysis reaction to form coumarin-3-carboxylic acid.Effects of factors such as dosage of catalyst,molar ratio of salicylaldehyde to diethyl malonate and reaction time et al on the yield of coumarin-3-carboxylic acid were examined.Results indicated that KF/K2CO3/γ-Al2O3 shows good catalytic activity.The optimal reaction conditions were identified.Under conditions as salicylaldehyde of 4.88 g（0.04 mol）,molar ratio of n（salicylaldehyde）∶n（diethyl malonate）=1∶1.25,catalyst dosage of 2.0 g（KF 3.74 mmol）,anhydrous ethanol（used as solvent for saponification） dosage of 20 mL,and reaction time of 1.5 h,yield of coumarin-3-carboxylic acid achieves 92% and higher.