A novel catalytic alkylation process of syngas with benzene over the cerium modified platinum supported on HZSM-5 zeolite

Abstract

The efficient conversion and utilization of syngas has become a hot scientific research topic, aiming to alleviate oil shortage and other related problems. In the present work, a novel one-step alkylation process of syngas with benzene was successfully developed to produce xylene and toluene over a catalyst containing platinum (Pt), cerium (Ce) and HZSM-5 zeolite. The introduction of Ce to the catalyst significantly improved the catalytic performance, resulting in the benzene conversion of 34.2% and total selectivity to xylene and toluene of 96.7% at 500 °C under 3.0 MPa, much better than those obtained over the catalysts containing no Ce under same conditions. The characterization results indicate that the introduction of Ce changed the acid properties of zeolite and Pt form, and improved the dispersion of Pt. In addition, the Ce covered some Bronsted acid sites on zeolite and lowered the Bronsted/Lewis acid ratio, which also contributed to the high selectivity to xylene and toluene. The in-situ FTIR analysis and reaction mechanism study revealed a two-step reaction route with methanol as the intermediate. Based on these results, a possible reaction pathway was proposed. Our work has provided a novel strategy for the production of xylene and toluene from benzene and syngs, which will improve the full unitlization of other resources than crude oil.