Highly efficient catalytic conversion of biomass-derived 2,5-dimethylfuran into renewable p-xylene over zirconium phosphate catalysts

A series of zirconium phosphates (ZrP- x ) with various P/Zr ratios were prepared. Among the catalysts, ZrP-2.5 with a high specific surface area of 410.9 m 2 ·g −1 and abundant mesopores exhibited outstanding catalytic performance in the synthesis of p -xylene (PX) from 2,5-dimethylfuran (DMF) and ethylene. A high PX yield of 89.2% and a productivity of 72.3 mmol PX ·g cat −1 ·h −1 were achieved at 250 °C using a small amount of catalyst. The excellent catalytic performance of ZrP-2.5 was attributed to the synergy between the large quantities of acidic sites with appropriate acid strength distribution, balanced Brønsted and Lewis acidity, and abundant mesopores . In addition, the catalyst had excellent recyclability and stability. In-situ FT-IR spectra of adsorbed DMF and ethylene revealed the crucial roles of P-OH and the coordinately unsaturated Zr(IV) in the adsorption and reaction process, which is beneficial to understanding the reaction mechanism and designing highly efficient catalysts.