丙烷在负载型催化剂上脱氢反应的研究 Ⅲ.丙烷在氧化铝负载的铂-金属氧化物催化剂上的脱氢

INVESTIGATIONS ON DEHYDROGENATION OF PROPANE OVER SUPPORTED BI-COMPONENT CATALYSTS III.DEHYDROGENATIQN OF PROPANE ON ALUMINA SUPPORTED PLATINUM-METAL OXIDES CATALYSTS

第Ⅰ,Ⅱ报结果指出,氧化态锡对Pt/Al_2O_3具有助催化作用。本文通过对氧化脱氢过程类比分析,提出具有可变价态元素氧化物可替代Pt-Sn/Al_2O_3催化剂中氧化态锡组分,而与金属铂组分构成一系列具有良好催化性能的负载型双组分催化剂。对Al_2O_3负载的Pt-Ti,Pt-V,Pt-Cr,Pt-Mn及Pt-Fe催化剂评价结果表明,催化剂性能均随氧化态组分(Ti,V,Cr,Mn,Fe等)载量增加而逐步改善。

In our previous papers,it has been reported that oxidative tin could greatly promote the catalytic activity and stability of Pt-Sn/Al_2O_3.In this paper results of the selective oxidation of hydrocarbons over different catalyst combinations are compared.It was found that the oxidative tin in Pt-Sn/Al_2O_3 may be replaced by oxidative of elements which possess variable valences,such as the oxides of Ti,Zr,Hf,V,Nb,Ta,Cr,Mo,W,Mn,Tc,Re,Fe,Cd,In,Tl,Ge,Pb,As,Sb,Bi,Se,Te etc.Alumina supported Pt-Ti,Pt-V,Pt-Cr,Pt-Mn and Pt-Fe were prepared by coimpregenation,characterized by ESR and Mossbauer spectroscopy,and evaluated by the dehydrogenation of propane in a fixed-bed reactor.The results showed that the catalytic components other than platinum in the catalysts were still in their oxidative states after reduction at 480℃.It was found that the catalytic performances were influenced not only by the loading but also by the nature of the oxides.The catalytic acti vity and selectivity increased with the loading of oxidativee components while maintaining the loading of platinum constant.However,the catalytic stability was dependent on the nature of the oxidative components.