沸石催化剂上二乙苯烷基转移反应中水的作用

The Effect of Water on the Catalytic Performance of FX 01 Catalyst for Transalkylation of Diethylbenzene with Benzene

考察了沸石催化剂ＦＸ０１上苯与二乙苯的烷基转移反应，发现反应原料中存在的水及催化剂表面吸附的水对ＦＸ０１催化剂的活性和选择性均有较大影响。随着预处理温度的升高，催化剂表面Ｂ酸量减少，Ｂ酸强度增加，反应活性提高，选择性降低。转化率随原料中含水量的增加而降低，选择性随之升高。原位红外结果说明，吸附的水降低了催化剂对苯及二乙苯吸附能力的同时也减缓了二乙苯的分解稠化程度。水的这种作用可归结为改变了催化剂表面的酸性质。

The effect of water on the activity and selectivity of FX 01 catalyst based on zeolite β for transalkylation of diethylbenzene with benzene has been studied.The water contained in both reactant and catalyst has strong influence on the catalytic performance of FX 01 catalyst for the title reaction.At lower reaction temperature,the conversion decreases and selectivity increases with increasing water content of the reactant,while at higher temperature water content has little effect on catalyst activity.It implies that at higher temperature water is difficult to be adsorbed on catalyst surface.The water content of catalyst depends on pretreatment temperature.The better pretreatment temperature is 250～280 ℃.The water content on catalyst surface and therefore B acid amount decreases with increasing pretreatment temperature;however,B acid strength enhances.The result of in situ IR shows that absorbed water on the surface of catalyst can prevent the cracking of diethylbenzene.