Catalytic Hydrogenolysis of Biomass-derived Polyhydric Compounds to C2–C3 Small- Molecule Polyols: A Review

Biomass energy has attracted much attention because of its clean and renewable characteristics. At present, C2–C3 polyols such as glycerol, 1,2-propanediol, and ethylene glycol, widely used as platforms for downstream chemicals or directly used as chemicals in diversified industries, mainly depend on the petrochemical industry. In terms of the feedstock for C2–C3 polyol production, the C3-derived glycerol is a side product during biodiesel synthesis, whereas the C5-derived xylitol and C6-derived sorbitol can be mainly obtained by hydrolysis–hydrogenation of hemicellulose and cellulose from lignocellulosic biomass, respectively. In this review, we summarize the catalysts and catalysis for selective hydrogenolysis of these polyhydric compounds to C2–C3 polyols and introduce the reaction pathways for the target polyol formation based on the C3, C5, and C6 polyhydric alcohol hydrogenolysis. Finally, state-of-the-art technologies are described and the remaining challenges and further prospects are presented in view of the technical aspects.