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.

p-Xylene, the precursor for PET bottles, was synthesized at 90% yield by [4 + 2] cycloaddition of biomass-derived ethylene and dimethylfuran followed by subsequent dehydration with Beta zeolite. Scheme 1 Diels-Alder cycloaddition of dimethylfuran [1] and ethylene produces an oxa-norbornene cycloadduct [2] which dehydrates to p-xylene [3]. Water hydrolyzes dimethylfuran [1] to 2,5-hexanedione [4] in equilibrium. † Electronic supplementary information (ESI) available. See

Cascade‐sensitized 800 nm excited tri‐doped upconversion nanoparticles (UCNPs) are developed for the first time. This novel class of UCNPs employ Nd3+ as an 800 nm photon sensitizer and Yb3+ as a bridging ion, and show strong upconversion emission without photobleaching. They outperform classical 980 nm excited UCNPs in regard to significantly decreased NIR photon absorption in water and decreased laser‐induced water heating effects.

p-Xylene was synthesized by [4 + 2] cycloaddition of biomass-derived ethylene and dimethylfuran over Lewis acid zeolite catalyst, Zr-BEA, with 90% selectivity in products.