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Effect of calcination temperature on CrO x –Y2O3 catalysts for fluorination of 2-chloro-1,1,1-trifluoroethane to 1,1,1,2-tetrafluoroethane
- Source :
-
Journal of Catalysis . Jan2008, Vol. 253 Issue 1, p1-10. 10p. - Publication Year :
- 2008
-
Abstract
- Abstract: A series of CrO x –Y2O3 catalysts were prepared by a deposition–precipitation method and tested for the fluorination of 2-chloro-1,1,1-trifluoroethane (CF3CH2Cl) to synthesize 1,1,1,2-tetrafluoroethane (CF3CH2F). The highest activity was obtained on a pre-fluorinated catalyst calcined at 400 °C, with 19% of CF3CH2Cl conversion at 320 °C. The effect of the calcination temperature on the CrO x species was investigated. X-ray diffraction and Raman results indicated that the CrO x species (Cr(VI)) were well dispersed on the catalyst surface when the catalyst was calcined at 400 °C. With increasing calcination temperature, most of the CrO x species changed from high oxidation state Cr(VI) to low oxidation state Cr(V) or Cr(III) species, which resulted in difficulty in pre-fluorination of the catalyst. It was also found that the CrF x , CrO x F y or Cr(OH) x F y phases originated from high oxidation state Cr(VI) species were the active sites for the fluorination reaction. [Copyright &y& Elsevier]
- Subjects :
- *CHEMICAL reactions
*CHEMICAL inhibitors
*OXIDATION
*CHEMICAL processes
Subjects
Details
- Language :
- English
- ISSN :
- 00219517
- Volume :
- 253
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- Journal of Catalysis
- Publication Type :
- Academic Journal
- Accession number :
- 27901211
- Full Text :
- https://doi.org/10.1016/j.jcat.2007.11.005