KNO_3/γ-Al_2O_3型固体超强碱催化合成香豆素的研究

对以水杨甲醛与乙酸酐为原料合成香豆素的工艺进行了改进。首次采用KNO3/γAl2O3固体超强碱催化剂的工艺路线,提高了产物的收率。同时对催化剂用量、反应物的量比、反应温度的影响进行了研究。结果表明,最佳工艺条件为:n(水杨醛)∶n(乙酸酐)=1.0∶1.6,催化剂用量为水杨醛质量的3%,反应近终点时在(210±2)℃,再保温反应0.5h,香豆素收率可达85%以上。该催化剂具有较高的催化活性,易于回收,可重复使用5次以上。

Study of coumarin catalyzed by KNO3/γ-Al2O3 solid superbase

The synthesis of coumarin from salicylaldehyde and acetic anhydride was improved with higher yield by using solid superbase (KNO_3/γ-Al_2O_3) for the first time. The influence of the amount of catalyst, the proportion of reactants, reaction temperature on yield was studied and the optimum technological conditions were that:n(salicylaldehyde)∶n(acetic anhydride)=1.0∶1.6, the amount of catalysts was 3% of salicylaldehyde, and the reaction is further for 0.5 h at (210±2)℃ when the reaction is close to the end point, under these conditions the yield of coumarin was over 85% and the catalyst can be recovered and reused for more than five times.