活性炭负载双金属催化剂的乙醇气相羰基化反应性能研究OA北大核心

Ethanol gas phase carbonylation is a non-petroleum route for the production of propionic acid,and Ni-based catalysts supported on activated carbon are widely used in this reaction.In order to enhance the catalytic activity,a series of Ni-X(X=Fe,Cu or Ce)bimetallic catalysts were prepared by further doping Fe,Cu or Ce on the basis of Ni-based catalysts.The effects of metal dispersion and Ni0 relative content n(Ni0)/n(Ni0+Ni2++Ni3+)on the reaction performances were investigated by N2 physical adsorption/desorption,XRD,XPS,etc.The activity of Ni-X bimetallic catalysts for ethanol gas phase carbonylation was evaluated under the conditions of 250 ℃,0.1 MPa and the feedstock(n(CO)∶n(C2H5OH)∶n(C2H5I)=40∶20∶1)space velocity of 1.2 h-1.The results show that there exists a synergistic interaction between Ni species and CeO2 on the surface of the Ni-Ce bimetallic catalyst,which promotes the reduction of Ni2+to Ni0 and the appearance of more active sites on the catalyst surface,as well as inhibits the surface accumulation of Ni metal and promotes the dispersion of Ni metal.Compared with Ni-Fe and Ni-Cu bimetallic catalysts,the Ni-Ce bimetallic catalysts have the highest catalytic activity,and the ethanol conversion rate,combined selectivity of propionic acid and ethyl propionate and combined space-time yield of the catalyst at 6 h are 70.9％,28.0％ and 220.4 mg/(g h),respectively.