Y分子筛介微孔结构与酸性对苯加氢烷基化反应的影响

Effect of Meso-Micro-Pore Structure and Acidity of Zeolite Y on Hydroalkylation of Benzene

通过不同的后处理方法制备了具有不同介微孔结构和酸性的Y分子筛,将这些分子筛制备成加氢烷基化催化剂,并进行了苯的加氢烷基化反应评价。实验结果表明,高酸量的催化剂具有高加氢烷基化活性,有利于提高环己基苯(CHB)和二环己基苯(DCHB)的选择性,加氢产物环己烷(CH)选择性降低。但由微孔Y分子筛制备的催化剂活性会逐渐下降,而由介孔Y分子筛制备的催化剂,若酸量充足,加氢烷基化活性稳定,苯的转化率和烷基化产物的选择性提高,并表现出高的DCHB产率和p-DCHB选择性。因此,为了提高催化剂的加氢烷基化活性及稳定性,不仅需要保证催化剂具有足够的酸性中心数目,还需要提高分子筛的介孔占比。

Y zeolites with different meso-micro-porous structures and acidity were prepared by different post treatments.These Y zeolites were prepared into hydroalkylation catalyst,and were evaluated by benzene hydroalkylation.The experimental results showed that the catalysts with high acid concentration had high hydroalkylation activity,which was beneficial to increase the selectivity of cyclohexylbenzene(CHB)and dicyclohexylbenzene(DCHB),and the selectivity of hydrogenation production cyclohexane(CH)was decreased.However,the activity of the catalyst prepared by microporous Y zeolites gradually decreased.If the acid amount was sufficient,the catalysts prepared by mesoporous Y zeolites showed stable hydroalkylation activity.The conversion of benzene and the selectivity of alkylation products were improved.High yield of DCHB and selectivity of p-DCHB were observed.Therefore,in order to increase the hydroalkylation activity and stability of catalysts,it was not only necessary to increase the number of acidic centers,but also to increase the mesoporous ratio of zeolite.