Pd/C catalyzed room-temperature, atmospheric pressure hydrogenation of furanic bio-oils from acidic ionic liquid catalyzed liquefaction of biomass in acetone

Furanic bio-oils were produced from liquefaction of corn cobs and switchgrass using 1-(3-propylsulfonic)-3-methylimidazolium chloride catalyst in acetone at 120 °C, 5 h. The biomass conversions to bio-oils for corn cobs and switchgrass were 43.8 ± 1.9 and 40.2 ± 1.4% (w/w) respectively. The bio-oils were then catalytically hydrogenated in water: methanol 3:1 (v/v) at room-temperature and atmospheric pressure using 5% Pd-C catalyst to give hydrogenated bio-oils and analyzed using GC–MS to identify the products. GC–MS analysis revealed that majority of the products in hydrogenated bio-oils is C4-C17 alcohols, ethers and furans. A total of 64 products were observed in GC–MS and 61 were identified with the use of mass spectroscopy. These products are arising from the partial reduction as well as deoxygenation of biomass derived furan aldehyde - acetone cross aldol products and acetone self condensation products. In addition, NMR analysis was used to quantify the effect of catalytic hydrogenation. 1H NMR spectra peak integration for the alkene-furan region (6.0–8.0 ppm) showed reductions of 19.0 to 1.8% and 19.1 to 2.6% due to the catalytic hydrogenation of bio-oils from corn cobs and switchgrass, confirming the effect of Pd-C catalyzed, 1 Atm., room temperature hydrogenation.