首先以六甲基乙二铵二甲硫酸盐(EDAS)、六甲基己二铵二甲硫酸盐(HDAS)及六甲基癸二铵二甲硫酸盐(DDAS)三种不同链长双季铵盐改性膨润土，然后用HCl活化，制备酸化双季铵型有机膨润土。采用N 2吸附技术、XRD、IR、TG及SEM等分析手段表征，并以乙酸与正丁醇的酯化反应为探针，初步研究其催化性能和结构关系。结果表明，酸活化及有机改性改变了膨润土的层状硅酸盐结构，比表面积及孔体积均增加，主要是由微孔比例增加引起；双季铵盐成功进入到膨润土层间，并以单层平卧的方式排列。酸活化有机膨润土使乙酸的转化率提高了20%~30%，通过正交实验得到较优的酯化条件为：正丁醇与乙酸的摩尔比2.5，反应温度130℃，反应时间4 h，催化剂用量0.4 g。%Hexamethyl ethyl diammonium methylsulfate (EDAS), hexamethyl hexyl diammonium methylsulfate (HDAS) and hexamethyl decyl diammonium methylsulfate (DDAS) were used to modify bentonites separatively, which were then activated with HCl to obtain acid-treated organobentonites. The microstructure of the organobentonites was respectively characterized by N2 adsorption, IR, X-ray diffraction, thermogravimetric analysis and SEM, and their catalytic activity was studied through the esterification reaction of acetic acid andn-butyl alcohol. The results show that the silicate layer skeleton structure changes after organic modification and acid-treatment, and the specific surface area and pore volume of the bentonite increase, which is mainly caused by the increase of micropores. Quaternary ammonium salts readily intercalate into the bentonite interlayer and arrange in monolayer state. The conversion of acetic acid increases by 20%~30% when using acid-treated organobentonites as catalysts. Optimized conditions were obtained by orthogonal test as follows: the molar ratio ofn-butyl alcohol to acetic acid is 2.5:1.0, reaction temperature is 130℃, reaction time is 4.0 h and catalyst dosage is 0.4 g.
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