Hydrodeoxygenation Of Lignin-derived Phenolic Compounds To Aromatic Hydrocarbons

To overcome the shortage of fossil fuels and environmental pollution which are caused by using fossil fuels.People begin to seek renewable energy and new energy to replace fossil fuels.Biomass is the only renewable carbon resources which can be converted into liquid hydrocarbon fuels in new energy,Which has become a research focus in the scientific and technical workers.Lignin is a polymer in natural which consists of hydroxy benzene propane(H)and guaiacyl benzene propane(G),and syringl benzene propane(S).What's more,it has high energy density.The liquid by lignin depolymerization with high oxygen content has low calorific value,unstable chemical properties and high viscosity.It's necessary to reduce the oxygen content in the biomass liquid fuels by hydrodeoxygenatiaom(HDO).Therefore,this work aimed at the hydrodeoxygenation of lignin-derived phenolic compounds to aromatic hydrocarbons on catalyst whose key component is MoO3.MoO3 catalyst was prepared by calcination using(NH4)6Mo7O24.4H2O as precursor and was characterized by XRD,XPS,H2-TPR and low temperature N2 adsorption.The hydrodeoxygenation of phenol model compounds was carried out to test the catalytic performance.The focus was the effects of reaction temperature,reaction time and N2 partial pressure on the phenol conversion and selective of target product.The catalytic mechanism of phenol HDO over MoO3 and the recyclability of catalyst were also discussed.The results showed that MoO3 can effectively convert phenol to benzene with high yield under optimal conditions(340 ?,PH2=0.5 MPa,PN2=3 MPa).And the oxygen vacancy site of MoO3 was deemed to be the active center in the hydrodeoxygenation of phenol,which accounts for the hydrolysis of CAR-OH to benzene.In addition,MoO3 exhibited excellent recyclability.The catalytic activity remains at the same high level when the catalyst was repeatedly used for three times in the HDO of phenol.This work explores the hydrodeoxygenation of phenol model compounds on MoO3/SiO2 catalyst.Effect of preparation methods,MoO3 dosage and reaction temperature in reactant conversion and product selectivity was investigated.The results showed that MoO3/SiO2 can effectively convert guaiacol to aromatic hydrocarbons with high yield under optimal conditions.Step by step precipitated MoO3/SiO2 with high catalytic activity because of high levels of Mo5+,Which is the active component in the hydrodeoxygenation of phenol model compounds.Little carbon deposit in reactioned catalyst indicates well carbon deposit resistance,and that,the catalyst after reaction remains the same catalytic activity by calcination.The hydrodeoxygenation of heavy fraction of bio-oil inevitably appers coking phenomenon because of its extremely complex composition,which leads to catalyst deactivation.This artical explores the hydrodeoxygenation of heavy fraction of bio-oil on MoO3 and MoO3/SiO2 catalyst.The result indicates MoO3/SiO2 catalyst with better catalytic activity.