磷钨酸催化剂催化合成缩酮

以磷钨酸为催化剂，系统探讨了丁酮、环己酮分别与乙二醇、1，2-丙二醇反应生成缩酮，乙酰乙酸乙酯分别与乙二醇、1，2-丙二醇反应生成苹果酯、苹果酯-B的优化条件。系统探讨了催化剂用量、反应物的物质的量之比、反应时间对产品收率的影响。结果表明，磷钨酸是合成缩酮的优良催化剂，在醇酮(酯)摩尔比为1．5：1，催化剂用量为反应物料总质量的0．5％，反应时间1．0h的优化条件下，苹果酯收率为82．2％，苹果酯-B收率为90．3％，环己酮乙二醇缩酮收率为74．0％，环己酮1，2-丙二醇缩酮收率为77．6％，丁酮乙二醇缩酮收率为52．4％，丁酮1，2-丙二醇缩酮收率为70．1％。

Synthesis of Ethyl Acetoacetate 1,2-Propanediol Ketal Catalyzed with Phosphotungstic Acid

Catalytic activities of acid in synthesizing ethyl acetoacetate ethylene ketal, ethyl acetoacetate 1,2 propanediol ketal, cyclohexanone ethylene ketal, cyclohexanone 1,2 propanediol ketal, butanone ethylene ketal, and butanone 1,2 propanediol ketal were studied. It demonstrates that phosphotungstic acid is an excellent catalyst. Various factors concerned with these reactions were investigated. The optimum conditions were found, that is, the molar ratio of glycol to ethyl acetoacetate/ketone is 1.5/1, the mass ratio of the catalyst used to the reactants is 0.5%, and the reaction time is 1.0 h. Under these conditions, the yield of ethyl acetoacetate ethylene ketal is 82.2%, ethyl acetoacetate 1,2 propanediol ketal is 90.3%, the yield of cyclohexanone ethylene ketal is 74.0%, the yield of cyclohexanone 1,2 propanediol ketal is 77 6%, the yield of butanone ethylene ketal is 52 4%, and the yield of butanone 1,2 propanediol ketal is 70.1%.