SO_4^(2-)/TiO_2/膨润土催化合成胡萝卜酸乙酯的研究

Study on Synthesis of Malonic Ester With SO_4^(2-)/TiO_2/Bentonite

采取丙二酸与乙醇为原料,以廉价膨润土为载体通过共沉淀-浸渍法生成的固体超强酸SO_4^(2-)/Ti O_2/膨润土作为催化剂,催化合成胡萝卜酸乙酯。分别探究不同醇酸摩尔比、反应时间、带水剂选择、带水剂用量、催化剂用量以及重复性对反应酯化率的影响。结果显示,当丙二酸用量为0.10 mol,醇酸摩尔比为3:1,催化剂用量为1 g,反应时间为3 h,带水剂环己烷用量为5 m L时,酯化率可达90.39%,催化剂重复使用6次,催化剂仍具有较高活性。表明该催化剂的催化活性很好,可以被推广。

The solid superacid SO4^（2-）/TiO2/bentonite was prepared by co-precipitation impregnation method with low-cost bentonite as carrier. Then malonic ester was synthesized from malonic acid and ethyalcohol with the solid superacid catalyst. The effect of experimental reaction conditions on the esterification rate was studied, such as the molar ratio of acid to isobutyl alcohol, the reaction time, the choice of the water-taking agent, the amount of water-taking agent, the amount of catalyst, reusability of the catalyst. The best reaction conditions were found as follows：the amount of malonic acid acid 0.10 mol, n（alcohol）：n（acid）=3：1, the dosage of catalyst 1 g, reaction time 3 h, the dosage of cyclohexane 5 m L. Under above conditions, the yield of esterification could reach 90.39%. The catalyst showed high activity after being reused for six times. The results show that the catalyst SO4^（2-）/TiO2/bentonite has good activity, and can be used widely.