以一水合硫酸氢钠为催化剂,间苯二酚和乙酰乙酸乙酯为原料,通过Pechmann缩合反应,在无溶剂条件下合成了7-羟基-4-甲基香豆素。探讨了反应温度、反应时间、催化剂用量及原料配比等因素对产品收率的影响。实验表明,一水合硫酸氢钠是合成7-羟基-4-甲基香豆素的良好催化剂,正交实验法得出反应的最优条件为:反应温度为110℃,反应时间40min,/Z(间苯二酚):n(乙酰乙酸乙酯)=1:1.2,催化剂用量为0.300g(间苯二酚物质的量为0.010mol)时,产品的收率为81.3%。
7-hydroxyl-4-methyl coumarin was one-pot synthesized through Pechmann reaction under solvent-free conditions, based on such two raw materials as ethyl acetoacetate and resorcinol, and monohydrated sodium bisulfate as catalyst. Such factors influencing on the yield of the product as reaction temperature, dosage of catalyst, reaction time and the molar ratio of the raw materials were discussed. The optimum conditions were established as following: the molar ratio of ethylacetoacetate to resorcinol was 1.2 : 1, the dosage of catalyst was 0.300 g (when the amount of resorcinol was 0.01tool) , the reaction temperature was at 110 ℃, and the reaction time was 40 min. Under the aforementioned conditions, the yield of 7-hydroxy-4-methyl coumarin reached 81.3%.