Selective and Efficient Production of Biomass-Derived Vinylfurans

We describe a two-step catalytic process for the selective and rapid conversion of biomass-derived acetylfurans into vinylfurans. This is accomplished by nearly quantitatively reducing acetylfurans into furyl alcohols using a copper chromite catalyst and exploiting the promoter-like properties of ethanol, the solvent. Subsequently, furyl alcohol is dehydrated using solid-acid catalysts. Catalyst deactivation due to oligomeric species is a major issue, but the activity can be partially recovered by calcination. Optimization of reaction conditions showed that the selectivity could be increased by using nitrobenzene, a polar aprotic solvent. The high-boiling point solvent allows the formation of vinylfurans with a selectivity of up to 85%; the product can be isolated in high purity by distillation.