Study on ethylbenzene and xylene conversion over modified ZSM-5

The effects of modification of H-ZSM-5 on its catalytic performance in the conversion of ethylbenzene (EB) and m-xylene were studied. The methods of silica chemical vapor deposition and 5,6-benzoquinoline adsorption can inactivate the external surface of ZSM-5, thus suppressing disproportionation and transalkylation side reactions with which isomerization selectivity and xylene yield increase at the expense of EB conversion and p-xylene yield. In contrast, platinum impregnation cannot only retard the side reactions but can also enhance EB conversion, p-xylene yield and catalyst stability. Combining those simple techniques into a multiple modification procedure provoked a synergistic effect enabling optimum design of a Pt/Si/ZSM-5 catalyst. According to reaction mechanisms, the present paper also briefly reviews different generations of commercial isomerization processes.

A multiple modification technique of H-ZSM-5, by combing silica chemical vapor deposition, 5,6-benzoquinoline adsorption and platinum impregnation, was developed having higher p-xylene yield and lower xylene loss than the existing commercial catalysts in the conversion of ethylbenzene (EB) and m-xylene.Figure optionsDownload as PowerPoint slide