Conversion of C 8 aromatics over a dual-bed catalyst.

A dual-bed catalyst was prepared for the conversion of C 8 aromatics. The upper bed layer consisted of ZSM-5 covered with SiO 2 , primarily utilized for ethylbenzene dealkylation. By employing tetraethyl orthosilicate (TEOS) as a deposition agent through the chemical liquid deposition (CLD) method, the modified ZSM-5 catalyst exhibited optimal catalytic performance at a TEOS addition of 0.6 g per gram of catalyst. The lower bed layer contained ZSM-39 catalyst, mainly employed for xylene isomerization reaction. ZSM-39 was synthesized using pyrrolidine as the template, and the best catalytic performance was achieved when the OH - /SiO 2 molar ratio in the synthesis system was 0.05. The mass ratio between the upper and lower agents was maintained at 1 : 1. Compared to traditional single-bed ZSM-5 catalysts, the dual-bed catalyst demonstrated enhanced activity and selectivity.