Preparation Of Modified Supporter Supported Ru-based Catalysts And Study Its Catalysis On Hydrogenation Of Benzene

Cyclohexene is an important organic chemical raw material.cyclohexene can be produced many important fine chemicals such as polyester,feed additives,medicine,pesticide and nylon.The route of selective hydrogenation to cyclohexene has the advantages of low cost raw material,of less by-products,low energy consumption and environmental protection,so it has attracted great attention of researchers.In this study,the modified P25 and sepiolite?SEP?supported Ru-based catalysts were prepared by wetness impregnation-sodium borohydride reduction method and applied in benzene Selective hydrogenation to cyclohexene.Moreover,the preparation conditions of the catalyst were optimized.The main work is as follows:?1?Sepiolite has a wide range of sources,low price,large specific surface area and good thermal stability.In this paper,sepiolite was firstly modified by 2mol/L hydrochloric acid,and then ZrO₂ was introduced into the modified sepiolite by hydrothermal crystallization and stirring method to prepare ZrO₂-SEP.Subsequently the ZrO₂-SEP was treated as supporter to prepare 8.0wt%Ru/ZrO₂-SEP catalyst,which was evaluated in benzene selective hydrogenation.The effects of catalysts prepared by introducing mode of ZrO₂,doping amount of ZrO₂,different preparation methods,and different of kinds and concentrations of acids on the catalytic performance were investigated.Nitrogen adsorption desorption characterization showed that ZrO₂-SEP supporter by stirring method has larger specific surface area,pore volume and pore size,and the larger pore size of the supporter is beneficial to the diffusion and desorption of cyclohexene so as to avoid it further hydrogenation to cyclohexane.The cyclohexene-thermogravimetric analysis showed that the complete desorption temperature of cyclohexene decreased gradually,with the content of ZrO₂ increases from 5.0wt.%to 20wt.%,which indicates that the adsorption strength of cyclohexene on the supporter is decreasing.8.0wt.%Ru/15wt.%ZrO₂-SEP catalyst was prepared presents,the best catalytic performance of55%conversion of benzen and 58%selectivity to cyclohexene under 0.08 amount of catalyst,150?reaction temperature,4.0MPa hydrogen pressure,1000rpm stirring rate,15min reaction time and 10mL 0.6mol/L ZnSO₄ solution,and yield of cyclohexene reached 31.9%.?2?P25?TiO₂?was composed with 80wt.%anatase and 20wt.%rutile mixed crystal,which has good hydrophilicity.In this paper,M-P25?M=Zn,Cu,Ni,Mn or Co?was prepared by modification of P25 with different metal promoter,and then it can be used as supporter to prepare 8.0wt.%Ru/M-P25.The characterization of XPS was showed that the electron transfer phenomenon of Ru in the catalyst after the reaction resulted in the formation of electron-deficient species was beneficial to the desorption of cyclohexene.Moreover,the analysis and characterization of static water contact angle showed that Zn doping could increase the hydrophilicity of Ru/Zn-P25 catalyst,which benefit the selectivity of cyclohexene.And 8.0 wt%Ru/1.0wt%Zn-SEP catalyst presents the optimum catalytic performance of 43%conversion of benzene and 68%selectivity to cyclohexene under 0.07 amount of catalyst,145?reaction temperature,4.0MPa hydrogen pressure,1000rpm stirring rate,15min reaction time and 10mL 0.6mol/L ZnSO₄ solution,and yield of cyclohexene reached 27.2%.