Development of High Performance Heterogeneous Catalysts for Selective Cleavage of C-O and C-C Bonds of Biomass-Derived Oxygenates

The environmental impact of CO2 emissions via the use of fossil resources as chemical feedstock and fuels has stimulated research to utilize renewable biomass feedstock. The biogenic compounds such as polyols are highly oxygenated and their valorization requires the new methods to control the oxygen to carbon ratio of the chemicals. The catalytic cleavage of C-O bonds and C-C bonds is promising methods, but the conventional catalyst systems encounter the difficulty to obtain the high yields of the desired products. This review describes our recent development of the high performance heterogeneous catalysts for the valorization of the biogenic chemicals such as glycerol, furfural, and levulinic acid via selective cleavage of C-O bonds and C-C bonds in the liquid-phase. Selective C-O bond cleavage by hydrogenolysis enables production of various diols useful as engineering plastics, antifreeze, and cosmetics in high yields. The success of the selective C-C bond scission of levulinic acid can be applied to a wide range of the biogenic oxygenates such as carboxylic acids, esters, lactones, and primary alcohols, in which the selective C-C bond scission at adjacent to the oxygen functional groups are achieved. Furthermore, valorization of glycerol by selective acetylation and acetalization, and of levulinic acid by hydrogenation is described. Our catalysts show excellent performance compared to the reported catalysts in the aforementioned valorization.