Catalytic conversion of guaiacol in ethanol for bio-oil upgrading to stable oxygenated organics

In this paper, guaiacol was used as a model compound of bio-oil and its catalytic conversion was carried out in ethanol. The effect of supports (SBA-15, ZrO 2 /SBA-15 and SO 4 2   − /ZrO 2 /SBA-15) was studied on Pt–Ni based catalysts whereas the effect of active metals was investigated over C-supported Ru, Pt and Pd catalysts. Among the tested catalysts, Ru/C showed the best performance of total guaiacol conversion with high selectivity towards the desired products, cyclohexanol and 2-methoxycyclohexanol (MCH). The reaction pathways of guaiacol in ethanol were clarified based on the product analysis. With the catalysis of Ru/C, the effects of reaction temperature, initial hydrogen pressure, and other typical compounds from bio-oil were investigated. Temperatures had negligible effect on both the conversion of guaiacol and the yields of desired products in the range of 140–260   °C. Guaiacol conversion decreased significantly at initial hydrogen pressures lower than 4.0   MPa. The presence of furfural , acetone , and acetic acid decreased the conversion of guaiacol dramatically while the addition of water had a smaller impact. Further work revealed that the mass and energy efficiency of converting guaiacol into MCH are 100% and 97%, respectively.