Production of isopropyl levulinate from furfural catalyzed by zirconium phosphate supported on nanosponge MFI zeolite through catalytic transfer hydrogenation

Alkyl levulinate is a kind of high value chemicals derived from biomass. Here, a nanosponge ZSM-5 supporting zirconium phosphate (ZrPO/NPZ) catalyst is prepared and used for catalytic transfer hydrogenation of furfural (FUR) to produce isopropyl levulinate (IPL) using isopropanol as H-donor. ZrPO specie provides Lewis acid sites together with additional Brønsted acid sites by ZSM-5 zeolite. Using the hierarchical ZSM-5 with exposed surface area as support, the dispersion of ZrPO active species increases, which facilitates the adsorption and conversion of FUR with the generation of 2-(isopropoxymethyl)furan (IPMF). The moderate Brønsted acid sites by zeolite promote the adsorption and activation of isopropanol, thus increasing the conversion rates of intermediate IPMF with formation of IPL. Furthermore, improved proportions of Brønsted/Lewis was detected with the increase of P/Zr ratios in the prepared catalysts, which is adverse for conversion of FUR. The optimized ZrPO/NPZ catalyst with P/Zr of 1 gives the best catalytic performance with IPL yield of ∼69 wt% after 3 h reaction at 200 °C (TOF of 6.98 mmol g⁻¹ h⁻¹), which provides an essential catalyst to produce IPL from FUR.