Catalytic Transfer Hydrogenation of Glucose to Sorbitol with Raney Ni Catalysts Using Biomass-Derived Diols as Hydrogen Donors

The catalytic transfer hydrogenation (CTH) of glucose to sorbitol has been studied using a wide collection of different biomass-derived alcohols and diols as hydrogen donors. Catalytic activity results reflect the feasibility to conduct this transformation in the presence of conventional, commercially available Raney Ni-type sponges as catalysts. Sacrificial diols displayed a superior performance as hydrogen donors as compared to short-chain alcohols, including secondary alcohols. Among them, terminal diols such as 1,4-butanediol and 1,5-pentanediol were revealed as excellent hydrogen donors, providing a high selectivity in the conversion of glucose into sorbitol. As for the catalysts, molybdenum promotion provided a very high catalytic activity to sponge nickel catalysts, even under mild temperature conditions. The transformation was also studied in a fixed-bed reactor under continuous-flow operation conditions. Results demonstrate that the catalysts are highly stable and able to operate for at least 550 h on stream with a high selectivity in the CTH of glucose to sorbitol.