Hierarchical ZSM-5 zeolites via alkali-acid etching, with synergistic mesoporous structure and acid sites, efficiently catalyze bioderived furfuryl alcohol to 4-hydroxy-2-cyclopentenone and DMF to p-xylene, showing excellent conversion and selectivity.

Abstract

Catalytic valorization of biomass into aromatic cyclic oxygen fine chemicals is crucial for reducing reliance on fossil resources and opens up new possibilities in sustainable chemistry. In this study, a series of mesoporous ZSM-5 zeolites catalyst was prepared via alkali and acid solution etching and showed an efficient catalytic performance for synthesizing 4-hydroxy-2-cyclopentenone with an extraordinary yield of 91.2% from bioderived furfuryl alcohol at 140 °C. Moreover, they demonstrated outstanding catalytic efficiency in the synthesis of cyclopentenones, achieving yields exceeding 65% from various furan derivatives (i.e., 2-furan methyl alcohol, 2-furan ethyl alcohol, and 5-methylfurfuryl alcohol). Additionally, in the Diels–Alder cycloaddition of DMF, ZSM-5-Si/Al₁₇₀-OH_0.3-HCl treated with NaOH and HCl exhibited excellent catalytic activity, presenting 63.7% selectivity of PX, which are also far superior to commercial ZSM-5. This synergistic effect of mesoporous property, more Al_single sites, suitable Lewis/Brønsted acid sites greatly improves the catalytic isomerization. Furthermore, ZSM-5-Si/Al₁₇₀-OH_0.3-HCl demonstrated the ability to be reused for four reaction cycles while maintaining its catalytic activity without notable decline. This study offers an effective and environmentally friendly catalytic system for synthesizing cyclopentenones and P-xylene, while also showcasing the catalytic improvement achieved through modification of zeolites.