ZSM-5 zeolite was modified by chemical liquid deposition with silane coupling agent KH540,methyl silicone oil and tetraethyl orthosilicate(TEOS).X-ray diffraction,scanning electron microscopy,NH3 temperature-programmed desorption and N2 adsorption-desorption were used to characterize the morphology,acidity and pore structure of the modified catalysts.In order to evaluate the catalytic performance,the cracking reaction of 1,3,5-triisopropylbenzene(TIPB)was used as a probe reaction to determine the acid density on the outer surface of the modified catalyst,and the modified catalyst was used for the ethylbenzene isomerization.The results showed that the TIPB conversion of the modified catalyst decreased,which indicated that the acid content on the surface of the modified catalyst decreased.The conversion of ethylbenzene was increased and the isomerization activity was decreased by adjusting the modification conditions.The optimum mass fraction of TEOS was 30％,the TIPB conversion was approximately 30％,the ethylbenzene conversion,isomerization activity and xylene yield were 98％,5％and 100％,respectively,and benzene selectivity was around 89％.
维普
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