蒙脱石负载铝基固体酸的制备及其催化性能

采用浸渍法制备了蒙脱石负载铝基固体酸(SO_4~(2-)/Al-O-MMT),用FTIR、XRD、TG/DSC、SEM、BET和PyFTIR对其结构进行表征与分析。以乙酸-正丁醇、柠檬酸-正丁醇的酯化反应为探针,研究了焙烧温度、浸渍液浓度对SO_4~(2-)/Al-O-MMT固体酸催化性能的影响,并测定SO_4~(2-)/Al-O-MMT固体酸的重复使用性。结果表明:蒙脱石负载铝基固体酸大大地提高了其催化活性。当焙烧温度为400℃,浸渍液浓度为0.75 mol/L时,SO_4~(2-)/Al-OMMT固体酸表现出最佳的催化活性,其催化合成乙酸正丁酯和柠檬酸三丁酯的酯化率分别可达到99.7%和96.1%。同时,SO_4~(2-)/Al-O-MMT固体酸表现出较好的重复使用稳定性,重复使用6次后,对于上述两个反应的酯化率分别保持在89.0%和84.6%。

Synthesis and Catalytic Performances of Al-based solid acid supported on montmorillonite

Al-based solid acids supported on montmorillonite (SO42-/Al-O-MMT) were prepared by impregnation method. The catalytic performance of esterification reactions towards acetic acid with n-butanol and citric acid with n-butanol were investigated. The as-prepared catalysts were characterized by XRD, IR, TG-DSC, SEM, BET and Py-FTIR. The synthesis conditions and reaction parameters of esterification reactions were optimized in details as well. The experimental results showed that the catalytic activity of Al-based solid acids supported on montmorillonite has been greatly improved. TheSO42-/Al-O-MMTsolid acid catalyst showed optimal catalytic activities with 99.7% conversion of acetic acid and 96.1% conversion of citric acid when the calcination temperature was 400 °C and the impregnation concentration was 0.75 mol/L. Moreover, the SO42-/Al-O-MMTsolid acid catalyst maintained its high activity with above 89.0% conversion of acetic acid and 84.6% conversion of citric acid after being used for six times, which indicated that the SO42-/Al-O-MMTsolid acid catalyst showed great stability.