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6657434 
Journal Article 
Ethylbenzene dehydrogenation to styrene in the presence of carbon dioxide over supported chromia catalysts 
Ye, XN; Hua, WM; Yue, YH; Miao, CX; Xie, ZK; Gao, Z; , 
2004 
1 
Chinese Journal of Catalysis
ISSN: 1872-2067 
SCIENCE PRESS 
BEIJING 
25 
7 
581-585 
Chinese 
WOS:000223181200016 
The chromia catalysts supported on gamma-Al2O3 and SiO2 were prepared by impregnation method, and their catalytic activity for ethylbenzene (EB) dehydrogenation in the presence of CO2 were investigated. The Cr2O3/Al2O3 catalyst was much more active than Cr2O3/SiO2, which might be due to the much better dispersion of Cr2O3 on gamma-Al2O3 than that on SiO2. The maximum ethylbenzene conversion of 59.0% over Cr2O3/Al2O3 appeared when w(Cr2O3) = 25%, which was slightly higher than the dispersion threshold of Cr2O3 on gamma-Al2O3 support. The dispersed chromia species were more active than the crystalline ones. Compared with pure N-2 atmosphere, CO, atmosphere showed an obvious promoting effect on EB dehydrogenation. Under the same reaction conditions, the Cr2O3/Al2O3 catalyst displayed better catalytic performance than Fe2O3/Al2O3 and V/MgO catalysts. The XPS and TPR results revealed that both Cr6+ and Cr3+ species were present on the Cr2O3/Al2O3 catalyst, and the Cr6+ species were probably the precursors of the active sites for EB dehydrogenation. 
Alumina; Carbon dioxide; Chromia; Dehydrogenation; Ethylbenzene; Silica; Styrene; Supported catalyst