负载磷钨酸催化苯与乙烯液相烷基化

以负载磷钨酸为催化剂 ,考察催化剂预处理温度、反应温度、原料苯中溶解水量、苯烯摩尔比和苯进料质量空速对苯与乙烯液相烷基化反应的影响。实验表明 ,负载磷钨酸的催化活性和预处理温度密切相关 ,在 2 10℃预处理时 ,催化活性最高 ;负载磷钨酸在 14 0℃以上 ,具有很高的催化活性和很好的乙苯选择性。在优化的反应条件下 ,乙烯的转化率为 10 0 % ,乙苯的选择性大于 90 % ,乙基化的选择性大于 98%。

Liquid Phase Alkylation of Benzene with Ethylene Catalyzed by Supported 12-Tungstophosphoric Acid

Supported 12-tungstophosphoric acid was prepared by incipient impregnation of spherical silica gel with aqueous solution of 12-tungstophosphoric acid H 3PW 12 O 40 · n H 2O.Alkylation of benzene with ethylene catalyzed by supported 12-tungstophosphoric acid under liquid phase conditions has been studied,including the effects of pretreatment temperature of catalyst,reaction temperature,water content in benzene,molar ratio of benzene to ethylene in the feed,and weight hourly space velocity of feed on ethylene conversion and alkylation selectivity.The catalytic activity of catalyst is associated with its acidity,which is controlled by the pretreatment temperature and water content in benzene.The catalyst is very active and selective as long as reaction temperature is higher than 140 ℃.Furthermore,molar ratio of benzene to ethylene and WHSV of benzene greatly affect the conversion of ethylene and selectivity to ethylbenzene.Preferred reaction conditions are determined: reaction temperature 160～240 ℃,total pressure 2～3 MPa,molar ratio of benzene to ethylene 12～24,WHSV of benzene 5～10 h -1 ,and water content in benzene 20～50 g/m 3 Under such conditions,conversion of ethylene is 100%,selectivity to ethylbenzene is greater than 90%,and selectivity of ethylation is greater than 98%.