Cycloaddition of Biomass-Derived Furans for Catalytic Production of Renewable p-Xylene

• Published in: ACS catalysis 2012-06, Vol.2 (6), p.935-939
• Main Authors: Williams, C. Luke, Chang, Chun-Chih, Do, Phuong, Nikbin, Nima, Caratzoulas, Stavros, Vlachos, Dionisios G, Lobo, Raul F, Fan, Wei, Dauenhauer, Paul J
• Format: Article
• Language: English
• Subjects: catalysis (homogeneous), catalysis (heterogeneous), biofuels (including algae and biomass), bio-inspired, hydrogen and fuel cells, materials and chemistry by design, synthesis (novel materials), synthesis (self-assembly), synthesis (scalable processing)
• ISSN: 2155-5435; 2155-5435
• DOI: 10.1021/cs300011a

A renewable route to p-xylene from biomass-derived dimethylfuran and ethylene is investigated with zeolite catalysts. Cycloaddition of ethylene and 2,5-dimethylfuran and subsequent dehydration to p-xylene has been achieved with 75% selectivity using H–Y zeolite and an aliphatic solvent at 300 °C. Competitive side reactions include hydrolysis of dimethylfuran to 2,5-hexanedione, alkylation of p-xylene, and polymerization of 2,5-hexanedione. The observed reaction rates and computed energy barriers are consistent with a two-step reaction that proceeds through a bicyclic adduct prior to dehydration to p-xylene. Cycloaddition of ethylene and dimethylfuran occurs without a catalytic active site, but the reaction is promoted by confinement within microporous materials. The presence of Brønsted acid sites catalyzes dehydration of the Diels–Alder cycloadduct (to produce p-xylene and water), and this ultimately causes the rate-determining step to be the initial cycloaddition.