One-Pot Conversion of Carbohydrates in Biomass to Isobutyroin-Rich Branched Oxygenates: Carbohydrate Depolymerization and Methyl Introduction in Supercritical Methanol

This study proposes a one-pot conversion of carbohydrates in biomass to branched oxygenates in methanol, employing noble metal and alkali cation as catalysts. The main product, isobutyroin, is highly concentrated when the reaction temperature and consequent pressure reach the supercritical point of methanol. The type of alkali cation and ratio of feedstock/alkali also significantly influence the production of isobutyroin. In comparison to Na+, K+ favors the production of isobutyroin from carbohydrates in biomass, especially when a low feedstock/K+ ratio is used. The formation of isobutyroin is explained by a series of reactions starting from methanol and cellulose/hemicellulose-derived acetic acid intermediate based on an isotope-labeling experiment. The isobutyroin-rich products can be used as high-quality gasoline precursors or high-value-added chemicals.