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

• Published in: Microporous and mesoporous materials Vol. 242; pp. 118 - 126
• Main Authors: Mitsuyoshi, Daisuke, Kuroiwa, Koji, Kataoka, Yuta, Nakagawa, Takuya, Kosaka, Misaki, Nakamura, Koshiro, Suganuma, Satoshi, Araki, Yasuhiro, Katada, Naonobu
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.04.2017
• Subjects: Chemical vapor deposition of silica; MFI zeolite; Para-xylene; Shape selectivity; Toluene disproportionation; Shape selectivity; MFI zeolite; Chemical vapor deposition of silica; Toluene disproportionation; Para-xylene
• ISSN: 1387-1811; 1873-3093
• DOI: 10.1016/j.micromeso.2017.01.022

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 Brønsted 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. (Left) Schematic drawing of shape selective formation of para-xylene and benzene by toluene disproportionation on silica-modified MFI with suitable pore-opening size. (Right) Selectivity-conversion plots on various catalysts. Only the present study gave higher selectivity than the conventional process. [Display omitted] •High para-xylene selectivity 99.7% in toluene disproportionation was achieved at conversion = 10% on the silica/MFI.•The parent zeolite with small number of Brønsted acid sites on the external surface brought the high selectivity.•The selectivity was predominantly dependent on the diffusion rate of bulky molecule.