Shape selectivity in toluene disproportionation into para-xylene generated by chemical vapor deposition of tetramethoxysilane on MFI zeolite catalyst

Dependence of shape selectivity for para-xylene production by toluene disproportionation on conditions of chemical vapor deposition (CVD) of tetramethoxysilane on MFI (ZSM-5) zeolite were investigated in detail. The CVD after pelletization was necessary to obtain 0.7-1 mm particles with high selectivity. The influences of preparation conditions on the selectivity were investigated in detail to find the optimum conditions. The parent zeolite with small number of Bronsted acid sites on the external surface brought the high selectivity after the CVD. The catalyst prepared in the optimized conditions showed the selectivity 99.7% at ca. 10% of the toluene conversion. (C) 2017 Elsevier Inc. All rights reserved.