掺杂La_2O_3或CeO_2的V_2O_5/γ-Al_2O_3和Fe_2O_3/γ-Al_2O_3催化剂的乙苯脱氢性能

通过掺杂少量的稀土金属氧化物La2O3或CeO2,采用溶胶-凝胶法制备了3%La2O3-17%Fe2O3/γ-Al2O3,3%La2O3-17%V2O5/γ-Al2O3,3%CeO2-17%V2O5/γ-Al2O3催化剂(金属氧化物负载量均为基于载体的质量分数),并用于在CO2气氛下乙苯温和氧化脱氢制苯乙烯的反应。考察了不同催化剂对乙苯和CO2的转化率及苯乙烯选择性的影响。实验结果表明,在常压、600℃、n(CO2)∶n(乙苯)=10∶1、乙苯空速为15mmol/(g.h)、反应时间3h的条件下,3%La2O3-17%V2O5/γ-Al2O3催化剂呈现出良好的乙苯脱氢活性,乙苯转化率和苯乙烯选择性分别为78.0%和98.2%,CO2的初始转化率为5.8%。采用X射线衍射、红外光谱和热重-差热分析表征了反应前后催化剂的体相结构及热失重过程。

Oxidative Dehydrogenation of Ethylbenzene over V2O5/γ-Al2O3 and Fe2O3/γ-Al2O3 Catalysts Doped with La2O3 or CeO2

By doping of La2O3 or CeO2,La2O3-Fe2O3/γ-Al2O3,La2O3-V2O5/γ-Al2O3 and CeO2-V2O5/γ-Al2O3 catalysts were prepared by sol-gel method.Loading amounts of metallic oxide based on mass of γ-Al2O3 support.The catalysts were used in mild oxidative dehydrogenation of ethylbenzene(EB) to styrene in presence of CO2.Effects of different catalysts on oxidative dehydrogenation were investigated.Fresh and used catalysts were characterized by means of XRD,IR and TG-DTA.Under appropriate reaction conditions: 3%La2O3-17%V2O5/γ-Al2O3 as catalyst,atmospheric pressure,600 ℃,n(CO2) ∶n(EB) 10 ∶1,EB space velocity 15 mmol/(g·h) and reaction time 3 h,conversion of EB,selectivity of styrene and initial conversion of CO2 can reach 78.0%,98.2% and 5.8%,respectively.