SO42-/SnO2-硅藻土型固体酸的制备及其对正丁酸与异戊醇的催化酯化

采用质量比为1∶3的SnCl₄·5H₂O和硅藻土制备的硅藻土Sn(OH)₄溶胶，70 ℃老化12 h，90 ℃干燥12 h、3.0 mol/L硫酸浸渍3 h、550 ℃焙烧3.5 h，制备了SO₄^2-/SnO₂硅藻土型固体酸催化剂。 利用IR、 XRD、TG测试技术表征了催化剂的理化性质。 用于催化正丁酸与异戊醇的酯化反应，当n（异戊醇）∶n（正丁酸）=1.4∶1、催化剂用量为反应物总质量的2.5%、10 mL苯、反应时间70 min时，酯收率为97.7％。 结果表明，该催化剂兼具多元氧化物型固体酸和硫酸酸化改性天然粘土固体酸催化剂的优点，催化活性高，成本低廉、制备方法简单并可适当回收循环使用。

Preparation of Solid Acid SO42-/SnO2-Diatomite and Its Catalytic Application for Synthesis of Isoamyl Butyrate

A solid acid SO₄^2-/SnO₂-diatomite was prepared by aging of diatomite-Sn(OH)₄ sol at 70 ℃ for 12 h, drying for 12 h at 90 ℃, impregnating in 3.0 mol/L H₂SO₄ for 3 h, and calcinating at 550 ℃ for 3.5 h. The solid acid was characterized by using IR, XRD and TG methods. The sol of diatiomite Sn(OH)4 was prepared with 1∶3 mass ratio of SnCl₄·5H₂Oto diatomite. Then isoamyl butyrate was synthesized from n-butyric acid and isoamyl alcohol in the presence of the composite solid acid as the catalyst. Effects of catalyst dosage, molar ratio of isoamyl alcohol to n-butyric acid, reaction time, and type of water entrainer on the yield of isoamyl butyrate（IAB） were examed. Under the optimized reaction conditions, n(isoamyl alcohol)∶n(n-butyric acid)=1.4∶1, reaction time in 70 min, benzene 10 mL, and the mass fraction of catalyst in total mass of reactants 2.5%, the yield of IAB was 97.7%. Compared with multi composite solid acid and SO₄^2-/clay, the prepared catalyst possesses advantages of low cost, high activity, facile preparation and easy separation from the reaction system. It can be reused to a certain extent.