采用水热合成法制备介孔ZrO2(M-ZrO2)和介孔TiO2(M-TiO2),并通过浸渍法负载S2O8^2-制备固体超强酸催化剂。以乙酸、乙醇的酯化反应为模型反应来考察制备条件对催化剂性能的影响。在(NH4)2S2O8溶液浓度为2.5mol/L、焙烧温度550℃、焙烧时间3h等情况下制得的S2O8^2-/ZrO2具有较高的催化活性,乙酸的转化率可达到51.4%。在S2O8^2-/ZrO2固体超强酸催化下进行柠檬酸和正丁醇的酯化反应,羧基转化率可达98.87%,产品纯度大于99.0%,且催化剂可重复使用3次。
Solid superacid catalysts from mesoporous zirconium and titanium oxides were prepared by hydrothermal synthesis, on which surface S2O8^2- was introduced by impregnation method. Esterification between ethanol and acetic acid was used as model reaction for examining the catalytic activities of different solid acids. The optimum reaction condition is as follows: impregnating M-ZrO2 with 2.5 mol/L (NH4)2S2Os, and then calcined at 550 ℃ for 3 h. The conversion of acetic acid is up to 51.4 %. Tributyl citrate was prepared using S2O8^2 -/ZrO2 as catalyst, the carboxylic conversion of product was 98.87 % with 99 % purity. After easily separated from the products the solid acid catalyst could be reused 3 times without any disposal.