Production of Levoglucosenone and Dihydrolevoglucosenone by Catalytic Reforming of Volatiles from Cellulose Pyrolysis Using Supported Ionic Liquid Phase

Abstract

This paper presents a novel method for continuous production of a biomass-derived platform chemical, levoglucosenone (LGO), from cellulose without its pretreatment or use of solvent. First, cellulose is pyrolyzed, and then the volatiles are reformed over a catalyst consisting of a type of ionic liquid supported over porous char. The ionic liquid, having a moderate hydrogen-bond basicity, performs well in the dehydrative conversion of levoglucosan (LGA) and anhydrosugar oligomers in the volatiles to LGO at 275 °C. The catalytic reforming to LGO is highly selective, and consequently, the yield of LGO is determined mainly by the pyrolysis conditions that produce the LGO precursors. The highest LGO yield we obtained was 31.6% on a cellulose carbon basis (24.6 wt %) with fast pyrolysis that produced more precursors than the slow one. Furthermore, the reaction system is applicable to the production of dihydrolevoglucosenone (DLGO), a promising biobased alternative to dipolar aprotic solvents. Addition of hydrogen in carrier gas and a hydrogenation catalyst in the catalytic bed enables the production of DLGO, although improvement in hydrogenation selectivity is required in the present reforming system.