Reactions of furfural and acetic acid as model compounds for bio-oil upgrading in supercritical ethanol

The reactions of bio-oil model compounds furfural/acetic acid were carried out using supported Nickel catalysts in supercritical ethanol at 260 °C. The catalysts were prepared through the dry impregnation method with Al2(SiO3)3, SO42-/ZrO2/SBA-15 as the solid acid supports. The textural properties of the catalysts were characterized by X-ray diffraction (XRD), Transmission Electron Microscope (TEM), and N2 temperature programmed adsorption/desorption (N2-TPD). The liquid products were analyzed by gas chromatography-mass spectroscopy (GC-MS) and the recovered catalysts were evaluated by the thermogravimetry (TG), differential thermogravimetry (DTG) after 3 hours reaction. The results indicated that acetic acid was completely removed and the amount of aldehydes decreased evidently. The reaction in supercritical ethanol under pressured H2 is the combination of several basic upgrading reactions including hydrodeoxygenation, hydrogenation, catalytic cracking, esterification, and rearrangement. Based on the products analysis, reaction pathway for furfural conversion was discussed in this work