Catalytic conversion of sugars and polysaccharides to glycols: A review

Catalytic conversion of (ligno)cellulosic biomass at hydrothermal or pyrolysis conditions represent attractive approaches for the production of valuable oxygenated chemicals and platform molecules. Despite many efforts, there is still a knowledge gap in the fundamental phenomena occurring on the catalyst surface, considering the complexity of the reaction networks and catalyst behavior under reaction conditions. In this review, to gain a better understanding of the processes and for designing the most effective catalysts, the main reactions and possible products obtained from catalytic valorization of cellulose are discussed, focusing particularly on diols. The review illustrates how catalysts act for selective production of platform chemicals from cellulose and cellulose-derived sugars at both pyrolysis and hydrothermal conditions and systematically summarizes recent advancements of heterogeneous catalysts, with a view to structure-activity relationships for production of diols.