Solvent-free catalytic conversion of xylose with methane to aromatics over Zn-Cr modified zeolite catalyst

Abstract

One-pot catalytic co-conversion of xylose and methane to aromatics was investigated under solvent-free conditions. Aromatics are the major liquid products from xylose conversion. 57.6% yield of aromatics with 63.1% selectivity of BTEX, and 10.9% yield of solid residue are achieved over HZSM-5 modified with Zn and Cr species. It’s evidenced that methane presence could effectively improve the yield of aromatics and the selectivity of BTEX, and greatly reduce the formation of solid residue. The results of pyridine absorption and NH3-TPD measurements indicate that the distribution of Bronsted and Lewis acidic sites over the catalyst has a negligible effect on xylose conversion to aromatics. More acidic sites with higher ratio of weak acid sites could benefit the formation of aromatics with high BTEX selectivity during the xylose conversion. The possible reaction pathway involved in xylose conversion to aromatics is proposed based on pseudo-situ investigations. The findings in this work lead to a better understanding of the chemistry involved in xylose conversion, which could potentially contribute to the cost-efficient utilization of natural gas and biomass.