Practical DMSO-promoted selective hydrolysis-oxidation of lignocellulosic biomass to formic acid attributed to hydrogen bonds

Formic acid (HCO2H) is widely used in various chemical processes, applied in fuel cells, and considered as a promising candidate for hydrogen storage. Currently, industrial production of HCO2H mainly depends on fossil resources using multiple processes. Practical HCO2H production from renewable resources for the potential industrial application is rare. Herein, we demonstrate practical dimethyl sulfoxide (DMSO) (1 v%)-promoted selective hydrolysis-oxidation of lignocellulosic biomass to HCO2H, which is demonstrated by recycling experiments of near 10 gram-scale wheat straw with constantly high efficiencies. Mechanism studies on the major unit of lignocellulosic biomass, glucose, disclose that the high selectivity and yield of HCO2H are attributed to the hydrogen bonds of DMSO with generated gem-diol groups from the reaction of glucose, or the intermediates of glycolaldehyde and glyoxal with water (H2O). The formation of hydrogen bonds is indicated both by DFT calculations and IR experiments.