High-throughput screening of monometallic catalysts for aqueous-phase hydrogenation of biomass-derived oxygenates

Abstract

The initial reaction rates on a per site basis for aqueous-phase hydrogenation (APH) of different oxygenated compounds: including acetaldehyde, propanal, acetone, xylose, furfural, and furfuryl alcohol and aqueous-phase hydrogenolysis of tetrahydrofurfuryl alcohol (THFA) and xylitol were measured over various alumina-supported monometallic catalysts (Pd, Pt, Ru, Rh, Ni, and Co) in a high-throughput reactor. These oxygenated compounds have the same functionality that is found in aqueous solutions derived from biomass including pyrolysis oils and aqueous hydrolysis solutions. The initial rate of APH of the different carbonyls groups was dependent on the functionality of the feed molecule and catalyst used. Ru was the most active metal for APH of acetaldehyde, propanal, acetone, and xylose. Pd was the most active metal for APH of furfural and furfuryl alcohol. Only Pt and Ni catalysts were able to produce 1,2-pentanediol and 1,5-pentanediol from aqueous-phase hydrogenolysis of THFA. Ru was active for conversion of THFA but only made coke. The initial activity for aqueous-phase hydrogenolysis of xylitol decreased in the order of Ru>Co>Pt>Ni≥Pd. The initial rates of APH of carbonyl groups (CO bond) measured in this study decreased in the order: hydrogenation of acetone>hydrogenation of acetaldehyde and propanal>hydrogenation of xylose>hydrogenation of furfural. The initial rates of aqueous-phase hydrogenolysis of THFA and xylitol were much lower than the initial rate for APH of CO and CC bonds.