二氧化硅负载的硫酸高铈固体酸催化剂上的缩合反应

Condensation on the Silica-supported Cerium(Ⅳ) Sulfate Solid Acid Catalyst

通过溶胶-凝胶法和浸渍法制备了二氧化硅负载的硫酸高铈[Ce(SO4)2/SiO2]固体酸催化剂,研究了乙酰乙酸乙酯和1,3-丁二醇的缩合反应,考察了催化剂的焙烧温度、硫酸高铈的负载量、催化剂的浓度、原料摩尔比、反应时间对反应的影响。结果表明,与四水硫酸高铈相比,二氧化硅负载的硫酸高铈[Ce(SO4)2/SiO2]固体酸催化剂在乙酰乙酸乙酯和1,3-丁二醇的缩合反应中具有较高的催化活性和良好的稳定性。最佳条件为:焙烧温度为500℃、乙酰乙酸乙酯和1,3-丁二醇摩尔比为1∶1.2、硫酸高铈的负载量为15.0%、催化剂占乙酰乙酸乙酯的质量分数为7.5%、回流反应时间120 min,此时苹果酯的收率可达95.5%。

Silica-supported cerium（Ⅳ） sulfate [Ce（SO4）2/SiO2] solid acid catalyst was preparated by sol-gel and impregnation methods.The catalytic activities for condensation of ethyl acetoacetate with 1,3-butandiol were evaluated with the same condition.The effects of the calcination temperature of the catalyst,mass fraction of cerium（Ⅳ） sulfate,molar ratio of ethyl acetoacetate to 1,3-butandiol,mass fraction of Ce（SO4）2/SiO2 and reaction time were discussed in detail.It showed that Ce（SO4）2/SiO2 solid acid was more active than cerium（Ⅳ） sulfate tetrahydrate.The yield of fructone was more than 95.5% under the condensation conditions of calcination temperature of catalyst 500 ℃,mass fraction of cerium（Ⅳ） sulfate 15.0%,molar ratio of ethyl acetoacetate to 1,3-butandiol 1∶ 1.2,mass fraction of Ce（SO4）2/SiO2 in ethyl acetoacetate 7.5% and reaction time 120 min.The experiments also revealed that the Ce（SO4）2/SiO2 catalyst had good repetitious and reproducible stability.