Flexible regulation of C3=/C2= ratio in methanol-to-hydrocarbons by delicate control of acidity of ZSM-5 catalyst

Avery wide range of the C-3(=)/C-2(=) ratio from 0.72 to 7.56 with high C-2(=) + C-3(=) selectivity of around 66% in the methanol-to-hydrocarbons process can be realized over ZSM-5 catalyst in a fixed-bed reactor. We firstly conduct a single factor experiment of acidity, demonstrating that the acidity control of MTH catalyst is crucial to adjusting light olefins selectivity. Weak Bronsted acid sites favor to high C-3(=) selectivity (59.0%) due to the suppression of the conversion reactions from the alkene-based to arene-based cycle, while Lewis acid sites conduce to high C-2(=) selectivity (39.6%) due to the promotion of the conversion reactions for the aromatics formation and steric constraints of Lewis acid sites making the aromatics crack more efficiently to C-2(-). (C) 2017 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.