Zn-based Catalysts For Hydrodeoxygenation Of Phenolics From Biomass Oils

As the only carbon-containing renewable resource,biomass converted into chemicals and transportation fuels have been widely studied over the world.Bio-oil obtained from lignin biomass by fast pyrolysis contains 30-50%of aromatic oxygenated compounds,such as phenyl ethers,guaiacol,syenols,and so on.Catalytic hydrodeoxygenation is an effective way for conversion aromatic oxygenated compounds into light aromatics and cycloalkanes from carbonaceous renewable resources.In this paper,hydrodeoxygenation(HDO)of guaiacol(o-methoxyphenol)as the model compound of aromatic oxygenated compounds in biomass oil over Zn-based catalysts was studied for the first time,the main research results are showed as follows:1.SiO2,Al2O3,HZSM-5,Re-HY and HBeta supported Zn catalysts showed that the surface acidity and the existence form of highly dispersed Zn species on the catalysts were the main influencing factors for the HDO performance of the catalysts.The activity of the catalysts for guaiacol HDO to cyclohexane and BTX(such as benzene,toluene,xylene)was correlated with the total amount of acidic sites and the strength of acidic sites on the catalysts to a certain extent,was also positively correlated with the proportion of ZnOH+ in Zn species on the surface of molecular sieve.2.Zn/HZSM-5 catalysts modified by Mo,Co,Mn,V or Ce further revealed the relationship between the amount,the strength of acidic sites and the existence state of Zn species and the HDO activity of the catalysts.Mo or Co modified catalyst significantly improve the HDO activity and stability of the catalyst.In addition,Mo components can greatly improve the selectivity of the catalyst for aromatic hydrocarbon,while Co components can improve the selectivity of catalyst for cyclohexane.3.ZnMo/HZSM-5 catalyst with high HDO activity and stability for the conversion of guaiacol into aromatic hydrocarbons was developed by adjusting the ratio of Zn/Mo in ZnMo/HZSM-5 catalyst.Under the temperature of 400 ?,hydrogen pressure at 1.0 MPa and weight hourly space velocity of 0.5 h-1,the HDO activity reached 98%,and the products were almost all benzene,toluene and xylene with outstanding stability.