Optimization of Zr-Al-USY and Zr-Al-Beta zeolites catalysts for a one-pot cascade transformation of furfural to γ-valerolactone
Abstract
Conversion of renewable compounds to versatile platform molecules over environmentally friendly heterogeneous catalysts is of increasing demand. Bifunctional Zr,Al-containing large-pore zeolites stand as active, selective and reusable solid catalysts for a one-pot cascade transformation of biomass-derived furfural to γ-valerolactone, a platform molecule opening the way to various valuable chemicals.
However, the influence of zeolite structure type and the ratio between Al- and Zr-associated acid sites on the outcome of this catalytic reaction has not been fully elucidated. Here we have compared the performance of the most efficient large-pore zeolites USY and Beta with systematically varied Al/Zr ratios for the one-pot synthesis of γ-valerolactone from furfural using 2-propanol or 2-pentanol as reacting solvents.
The optimization of the catalyst structure (USY) and chemical composition (Al/Zr = 0.6) enables to achieve the yield of targeted γ-valerolactone comparable to or even exceeding the values previously reported for homogeneous or heterogeneous catalysis (88% after 24 h at 120 °C). The remarkable catalytic performance of the optimized Zr-Al-USY catalyst was related to the balanced ratio between Zr- and Al-associated acid sites catalyzing different steps of the studied cascade reaction.