Catalytic Valorisation of Biomass-Derived Levulinic Acid to Biofuel Additive γ-Valerolactone: Influence of Copper Loading on Silica Support

Abstract

γ-valerolactone (GVL) is a crucial chemical feedstock used in the production of fuel additives, renewable fuels, and fine chemicals alternative to petroleum-based solvents and chemicals, supporting the transition to sustainable energy solutions. It is promptly acquired by hydrogenating levulinic acid (LA) in a gaseous or liquid phase with a homogeneous or heterogeneous catalyst using a variety of recognized catalytic processes. Herein, this work focuses on the use of silica-supported copper (Cu/SiO2) catalysts for the gas-phase hydrogenation of LA to GVL under mild reaction conditions. The study analyzes how copper loading can affect the catalytic activity of the Cu/SiO2, while the flow rate of LA, time-on-stream, reaction temperature, and LA concentration affect the catalytic efficiency. The SiO2 support’s various Cu loadings are crucial for adjusting the catalytic hydrogenation activity. One of the studied catalysts, a 5 wt% Cu/SiO2 catalyst, demonstrated ~81% GVL selectivity with ~78% LA conversion and demonstrated stability for ~8 h while operating at atmospheric pressure and temperature (265 °C) and 0.5 mL/h of LA flow rate. The ability to activate hydrogen, high amount of acidic sites, and surface area were all discovered to be advantageous for increased GVL selectivity.

Influence of Impurities in the Chemical Processing Chain of Biomass on the Catalytic Valorisation of Cellulose towards γ-Valerolactone

“…There are also multiple examples of deactivation of many other systems like Mg-Al hydrotalcite catalysts and Cu-and Co-based catalysts by the reduction of the active site surface area or pore volume [112][113][114]. For instance, in addition to the sintering of Cu nanoparticles, Boddula et al pointed out the role of coke deposits on active sites in the loss of activity in LA hydrogenation with time-on-stream observed on a 5 wt% Cu/SiO 2 catalyst at 265 • C after 20 h of reaction [113].…”