Solubilized Carbohydrate Production by Acid‐Catalyzed Depolymerization of Cellulose in Polar Aprotic Solvents

Abstract

AbstractThis paper explores the effectiveness of several polar aprotic solvents, including 1,4‐dioxane, ethyl acetate, tetrahydrofuran (THF), methyl iso‐butyl ketone, acetone, acetonitrile, and gamma‐valerolactone (GVL), in depolymerizing cellulose into solubilized carbohydrates in the presence of acid catalyst. Whereas the yields of solubilized carbohydrates were strongly dependent on the polar solubility parameters of solvents, the use of acid catalyst substantially eliminated differences in the yields for the various solvents, which were in the range of 83–97%. The yields of levoglucosan and solubilized carbohydrates from cellulose in 1,4‐dioxane, THF, and acetone approached that of GVL, almost completely solubilizing cellulose within 1–7 min. Low initial rates of levoglucosan degradation caused these low polarity, low boiling point solvents to exhibit high stability and competitive yields of the anhydrosugar compared to high polarity and high boiling solvent such as GVL. The ease of recovery of low polarity, low‐boiling solvents makes them attractive media for production of solubilized carbohydrates, which the use of acid catalyst makes possible.