Selective production of para-xylene by toluene disproportionation catalyzed by silica-deposited ZSM-5 zeolite

Abstract

Niwa et al. have found that the pore-opening size was uniformly controlled by the chemical vapor deposition (CVD) of silica on the external surface of ZSM-5 zeolite and shape selective synthesis of para-xylene was achieved by methylation and disproportionation of toluene using the silica-deposited ZSM-5.  We researched the change of activity, selectivity and catalyst life by the CVD for the practical disproportionation in this study.  A high selectivity was obtained without lowering the activity by the CVD at a relatively low temperature and long time.