Improvement of levoglucosenone selectivity in liquid phase conversion of cellulose-derived anhydrosugar over solid acid catalysts

The pyrolysis of cellulose produces anhydrosugars, levoglucosan (LGA) in particular, as a primary product. In this work, the liquid phase conversion of anhydrosugars over solid acid catalysts was investigated, mainly using LGA, as a method for producing levoglucosenone (LGO), which is a bio-renewable platform for fine and commodity chemicals. The screening of typical organic solvents revealed they had a significant influence on the type of reaction selectivity and identified dimethyl sulfoxide (DMSO) as a suitable solvent. Among the solid acid catalysts examined, Amberlyst 70 in combination with DMSO was found to work the best, producing LGO with a yield of up to 32.3%-C. The yield of LGO was further improved to 40.4%-C by in-situ removal of water, which promoted undesired reactions, such as hydrolysis of LGA and isomerization of LGO to hydroxymethylfurfural. Moreover, an experiment using bio-oil, derived from cellulose pyrolysis, as the feedstock showed that a portion of heavier saccharides contributed as a source of LGO without inhibiting the conversion of LGA.

Automated summary

This study found that using DMSO as a solvent in combination with Amberlyst 70 as a solid acid catalyst can significantly increase the yield of LGO, with further improvement achieved by in-situ removal of water. Additionally, experiments using bio-oil as feedstock showed that heavier saccharides can also serve as a source of LGO without inhibiting the conversion of LGA.