摘要
用IR-TPD,SEM,XPS,吸附动力学等手段研究了La浸渍前后HZSM-5沸石的表面酸性和孔性及其与催化乙苯乙烯烷基化反应性能间的关系。结果表明,二烷基苯在La浸渍改性的沸石孔内的扩散系数下降,异构体之间的扩散差别增大。La在浸渍覆盖沸石表面原有强酸中心的同时,诱导产生了次强B和L酸中心。新生的次强B酸中心量及其分布是影响烷基化反应活性和选择性的主要因素。新生的次强L酸中心也参与了烷基化反应。
Surface acid sites and channel properties of lanthanum impregnated HZSM-5 zeolites were investigated with IR-TPD, SEM, XPS and adsorption kinetics. Their correlation with the behavior of ethylbenzene alky-Jation with ethene was also studied. The results showed that lanthanum impregnation caused the decrease of the diffusion coefficients of dialkyl-benzene and the increase of the difference in ciffusion rates among diethylber,zene isomers. Lanthanum impregnation covered the original strong acid sites and induced simultaneously the formation of new sub-strong B acid sites and L acid s;tes. The amount and distribution of these new sub-strong B acid sites were the major factors that affecting the alkylation activity and selectivity. Moreover, the new sub-strong L acid sites also participated in the process of alkylation.
基金
国家自然科学基金
