Valorization of hemicellulosic sugars to sugar alcohols by Raney nickel mediated hydrogen transfer

Abstract

The versatility of the pathway to produce polyols from sugars through catalytic transfer hydrogenation (CTH) using commercial Raney nickel catalysts and 1,4-butanediol as hydrogen source has been explored. The results reveal that the nickel purity of the catalyst is a key parameter in process selectivity and presents the CTH route as a promising alternative to conventional hydrogenation processes, effective for the complete valorization of the sugar platform, including hexoses, pentoses and disaccharides. The study uncovers a significant influence of sugar structure on the resulting reactions, with threo-configured sugars displaying enhanced selectivity, while erythro-configured sugars demonstrate elevated conversion rates and the production of a broader spectrum of sugar alcohol isomers. Furthermore, a computational study, using density functional theory (DFT) calculations, has been carried out to describe the performance of the disaccharides and correlate it with their activity in the reaction media.