Production of renewable p-xylene from 2,5-dimethylfuran via Diels–Alder cycloaddition and dehydrative aromatization reactions over silica−alumina aerogel catalysts

• Cycloaddition of dimethylfuran for renewable p-xylene with silica−alumina aerogels
• The p-xylene yield is a function of the concentrations of the Brønsted acid sites.
• The rate of p-xylene production increases significantly in polar aprotic solvents.

We report the selective conversion of biomass-derived 2,5-dimethylfuran (DMF) to p-xylene (~ 70% selectivity) through Diels–Alder cycloaddition and subsequent dehydration with silica−alumina aerogel (SAA) catalysts. The high activity of SAA can be attributed to its high surface area, large mesoporous volume, and high acid site concentrations. The conversion of DMF and the yield of p-xylene were strongly dependent on the silica alumina ratio of SAA. A higher aluminum content in SAA led to a progressive increase in the concentration of Brønsted acid sites and a corresponding increase in the p-xylene production rate. The effect of solvent on the production of p-xylene was examined, and it was found that the p-xylene production rate increases significantly in polar aprotic solvents (i.e. 1,4-dioxane).