Catalyst-free synthesis of biodiesel precursors from biomass-based furfuryl alcohols in the presence of H2O and air

Production of biodiesel from biomass resources usually requires elongation of carbon numbers from typical C5 and C6 platform molecules through C–C coupling reactions, which were catalyzed by acid, base or metal catalysts traditionally. Herein, a catalyst-free method was developed to produce bis(furan-2-yl)methane derivatives (BFMs) from furfuryl alcohol derivatives (FAs) in the presence of H2O and air without any other additional catalysts. An 81% yield of bis(5-methylfuran-2-yl)methane (BMFM) can be obtained from 5-methylfurfuryl alcohol (5-MFA) and a 59% total yield of C11 biodiesel was obtained from 5-methylfurfural (5-MF). In addition, a H2O and air mediated free radical decarboxylation mechanism was proposed based on the detailed mechanistic studies. This strategy offers a green, low-cost and environmentally friendly approach to synthesize biodiesel precursors from biomass based platform molecules.