Solvent-Free Hydrogenation of 5-Hydroxymethylfurfural and Furfural to Furanyl Alcohols and their Self-Condensation Polymers.

Abstract

2,5-Bis(hydroxymethyl)furan (BHMF) as well as furfuryl alcohol (FFA) are considered as highly valuable biomass-derived alcohols resembling aromatic monomers in polymer synthesis. Herein, a series of cobaltic nitrogen-doped carbon (Co-NC) catalysts calcinated at different temperatures were synthesized and tested for the solvent-free hydrogenation of 5-hydroxymethylfurfural (HMF) to prepare BHMF. It was found that the Co-NC catalyst calcinated at 600 °C (Co-NC-600) exhibited a superior catalytic activity in the hydrogenation reaction mainly due to the doping of graphitic N, which probably facilitated the polarization of H2 to afford H+ and H- . Consequently, Co-NC-600 offered a high BHMF/FFA yield greater than 90 % with a nearly complete conversion of HMF/furfural (FF) at the optimal conditions (80 °C, 4 h, and 5 MPa H2 ). After the hydrogenation reaction, Co-NC catalyst was facilely recycled by magnetic separation, and the obtained BHMF/FFA was then successfully transformed into hypercrosslinked polymers with an excellent CO2 /H2 storage capacity comparable to aromatic hydroxymethyl polymers. Therefore, this is a novel and facile two-step pathway for the conversion of biomass-derived HMF/FF towards functional polymers from both industrial and environmental perspectives.