Vacancy Modification Of Sulfide Catalyst And Hydrodeoxygenation Of Lignin

Lignin is a renewable resource for the production of aromatic platform chemicals To achieve low-temperature and high-efficiency catalytic conversion of lignin model compounds.This study prepared a series of CoMo S catalysts with different vacancy based on vacancy engineering.The catalytic performance of model compounds to prepare aromatic hydrocarbons was investigated,and the specific structure of the catalyst and the relationship between structure and activity were explained through characterization and kinetic analysis.The structure-activity relationship provides guidance for the design of sulfide catalysts and the high-value utilization of lignin.First,by adjusting the hydrothermal process,a series of CoMo S catalysts with different vacancy properties were prepared,and their catalytic performance in the hydrodeoxygenation of p-cresol was investigated.The results show that the activity of the 0.15CoMo_1-xS_2-y catalyst obtained by Co-doping the double-vacancy Mo_1-xS_2-y is much higher than the single-vacancy 0.15CoMo S_2-y and the traditional 0.15CoMo S.Under the conditions of 170℃,6 h,3 MPa H₂,the conversion of p-cresol was 91.4%,and the yield of toluene was 90.1%,the selectivity of toluene was 98.6%.Combined with the characterization,it is speculated that the excellent activity is due to the CoMo S active phase formed by the Mo and S vacancies on the base surface and Co.Secondly,to further optimize the catalyst,this chapter thoroughly studied the influence of the cobalt source on the hydrodeoxygenation activity of the CoMo_1-xS_2-ycatalyst.The characterization results show that when cobalt acetate is used as the cobalt source,the proportion of CoMo S active phase reaches the highest.Under the reaction conditions of 160℃,6 h,3 MPa H₂,the conversion rate of p-cresol reached 96.6%,and the yield of toluene was 93.1%,the selectivity of toluene was 96.4%.Finally,this study extended the catalytic substrate to different types of lignin model compounds.The result show that the catalyst exhibits good dephenolic hydroxyl ability in all phenolic compounds.The reaction kinetics of catalysts with different vacancies found that the rich variety of vacancies had a more obvious effect on the promotion of the reaction.It further proves that the catalytic efficiency of the CoMo S phase formed by the double vacancies and Co on the basal plane is higher.