An account of the catalytic transfer hydrogenation and hydrogenolysis of carbohydrate-derived renewable platform chemicals over non-precious heterogeneous metal catalysts

Abstract

Sustainable and eco-friendly catalytic processes for renewable lignocellulose biomass conversion into liquid fuels and useful chemicals offer solutions to minimize greenhouse gases emission and associated negative climate impacts. Lignocellulose derived cellulose and hemicellulose can be converted into platform chemicals including glucose, fructose, xylose, 5- hydroxymethylfurfural, furfural, levulinic acid, levulinate esters, etc. These platform chemicals can be subsequently converted into liquid fuels and value-added chemicals using heterogeneous catalytic processes such as; oxidation, hydrogenation, hydrogenolysis, etc. The catalytic transfer hydrogenation and hydrogenolysis (CTH) over non-precious metal catalysts have recently drawn considerable research interest. This review summarizes recent progress on non-precious metals catalyzed CTH processes, which also include photocatalysis and electrocatalysis, for the transformation of 5-hydroxymethylfurfural, furfural, levulinic acid, and, levulinate esters into furfuryl alcohol, 2-methylfuran, 2,5-dimethylfuran, and, gamma-valerolactone; elucidate structure-function relationship and highlights the underlying reaction mechanisms. This review is timely and provides detailed fundamental insights about the nature of active sites and CTH processes that will be useful for the researchers willing to work in this exciting area.