摘要
采用浸渍法制备了负载型Cr2 O3 /Al2 O3 和Cr2 O3 /SiO2 催化剂 ,并考察了催化剂在CO2 气氛下催化乙苯脱氢制苯乙烯反应的活性 .结果表明 ,Cr2 O3 /Al2 O3 的催化活性高于Cr2 O3 /SiO2 .这可能是由于Cr2 O3 在Al2 O3 载体表面的分散度大大高于在SiO2 表面的分散度 .催化剂的催化活性与Cr2 O3 的负载量有关 ,在w(Cr2 O3) =2 5 %时 ,Cr2 O3 /Al2 O3 的催化活性最高 .CO2 气氛对乙苯脱氢反应有明显的促进作用 ;在CO2 气氛下 ,Cr6+
The chromia catalysts supported on γ Al 2O 3 and SiO 2 were prepared by impregnation method, and their catalytic activity for ethylbenzene (EB) dehydrogenation in the presence of CO 2 were investigated. The Cr 2O 3/Al 2O 3 catalyst was much more active than Cr 2O 3/SiO 2, which might be due to the much better dispersion of Cr 2O 3 on γ Al 2O 3 than that on SiO 2. The maximum ethylbenzene conversion of 59 0% over Cr 2O 3/Al 2O 3 appeared when w (Cr 2O 3)=25%, which was slightly higher than the dispersion threshold of Cr 2O 3 on γ Al 2O 3 support. The dispersed chromia species were more active than the crystalline ones. Compared with pure N 2 atmosphere, CO 2 atmosphere showed an obvious promoting effect on EB dehydrogenation. Under the same reaction conditions, the Cr 2O 3/Al 2O 3 catalyst displayed better catalytic performance than Fe 2O 3/Al 2O 3 and V/MgO catalysts. The XPS and TPR results revealed that both Cr 6+ and Cr 3+ species were present on the Cr 2O 3/Al 2O 3 catalyst, and the Cr 6+ species were probably the precursors of the active sites for EB dehydrogenation.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2004年第7期581-585,共5页
基金
国家自然科学基金资助项目 ( 2 0 3 0 3 0 0 4)
国家重点基础研究发展规划 ( 973 )资助项目 (G2 0 0 0 0 775 0 7)
上海市重大基础研究资助项目 ( 0 3DJ14 0 0 4)
上海市自然科学基金资助项目 ( 0 3ZR14 0 13 )
上海石油化工研究院资助项目
关键词
乙苯
脱氢
苯乙烯
氧化铬
氧化铝
氧化硅
负载型催化剂
二氧化碳
ethylbenzene, dehydrogenation, styrene, chromia, alumina, silica, supported catalyst, carbon dioxide
