Regulating zeolite acid-base sites for selective hydrogenation of 5-hydroxymethylfurfural

The hydrogenation of biomass-derived 5-hydroxymethylfurfural (HMF) to the value-added chemicals plays vital role in the development of renewable resources, while the precisely chemical regulation of products selectivity remains a great challenge. Herein, Zr-Beta based catalysts were fabricated with the controllable acid base sites for the selective hydrogenation of HMF. Importantly, the products selectivity could be facilely switched over Zr-Beta based catalysts: 100 % of 2,5-bis(isopropoxymethyl)furan (BPMF) selectivity was acquired over ZrBeta, whereas 99.4 % of 2,5-bis(hydroxymethyl)furan (BHMF) selectivity was achieved over K-Zr-Beta. The characterization analysis revealed that more Lewis acid sites in Zr-Beta facilitated Meerwein-Ponndorf-Verley (MPV) reduction of HMF and the further etherification of BHMF to acquire BPMF. However, the incorporation of K+ + into Zr-Beta could exchange with silanol protons and Zr(IV) sites, which resulted in the decrease of Lewis acid amount accompanied with the generation of base sites. Notably, the regulated acid and base sites in K-ZrBeta catalyst synergistically acted in the selective hydrogenation of HMF to BHMF. This work provides a feasible strategy for adjusting selectivity of HMF hydrogenation products by tuning the catalysts acid-base sites.