磷钨酸催化苯与多乙苯的烷基转移反应

TRANSALKYLATION OF POLYETHYLBENZENE WITH BENZENE CATALYZED BY TUNGSTOPHOSPHORIC ACID

采用搅拌高压釜 ,以磷钨酸为催化剂 ,研究了苯与多乙苯的烷基转移反应 ,多乙苯主要是二乙苯和三乙苯。结果表明 ,磷钨酸的预处理温度、反应温度、苯与多乙苯中乙基的摩尔比、反应原料中的水分及磷钨酸与反应原料的质量比 ,都显著地影响二乙苯和三乙苯的转化率以及乙苯的选择性。磷钨酸的催化活性和其酸强度密切相关 ,磷钨酸的酸强度越高 ,其催化活性也越高。磷钨酸的酸强度同时受预处理温度和反应原料中水分的影响。较好的烷基转移反应条件为 :磷钨酸预处理温度 2 10～ 2 30℃、反应温度 16 0～ 2 0 0℃、反应原料中的水分含量≤ 5 0mg/kg、苯与多乙苯中乙基的摩尔比 >6 6、磷钨酸与反应原料的质量比 >0 0 4 5 6。在上述反应条件下 ,二乙苯的转化率 >86 % ,三乙苯的转化率 >79% ,生成乙苯的选择性 >99%

The transalkylation of polyethylbenzene, mainly diethylbenzene and triethylbenzene, with benzene catalyzed by tungstophosphoric acid has been studied in stirred autoclave. Experimental results indicated that preheated temperature of tungstophosphoric acid, reaction temperature, molar ratio of benzene to ethyl of polyethylbenzene, water content in reactants and mass ratio of catalyst to reactants affect the conversions of diethylbenze and triethylbenzene and the selectivity of ethylbenzene markedly. The catalytic activity of tungstophosphoric acid is closely associated with its acidity. The stronger the acidity is, the more active the catalyst. Acidity of the catalyst is controlled by preheated temperature of catalyst and water content in reaction mixtures. The preferred operation conditions are: preheated temperature 210～230 ℃, reaction temperature 160～200 ℃, water content no more than 50 mg/kg, molar ratio of benzene to ethyl of polyethylbenzene larger than 6.6, and mass ratio of catalyst to reactants larger than 0.0456. Under such reaction conditions, the conversions of diethylbenzene and triethylbenzene are higher than 86% and 79%, respectively, and selectivity of ethylbenzene is higher than 99%.