Gluconic acid aqueous solution: A bio-based catalytic medium for organic synthesis

Abstract

Gluconic acid is non-toxic, non-volatile, non-corrosive, and easily biodegradable chemical, which can be produced from biomass using several methods: oxidation by molecular oxygen using heterogeneous catalysis, enzymatic oxidation, and microbial fermentation. Being highly soluble in water, gluconic acid can form concentrated aqueous solutions, and its 50% aqueous solution has found application as a catalytic medium for organic synthesis. For some reactions, gluconic acid aqueous solutions (GAAS) outperform conventional and green solvents when used as media for organic synthesis. GAAS was found to be particularly efficient in the Knoevenagel condensation, the Michael addition, and multicomponent reactions based on them. These and other chemical transformations utilizing GAAS as a medium are discussed in this review. We also compare the effectiveness of GAAS as a new green catalytic medium and the performance of other solvents and catalysts.