Effect of calcination temperature on CrOx–Y2O3 catalysts for fluorination of 2-chloro-1,1,1-trifluoroethane to 1,1,1,2-tetrafluoroethane

• DOI: 10.1016/j.jcat.2007.11.005
• Publication Date: 2007-12-06T16:36:33Z
• Authors: J HE; G XIE; J LU; L QIAN; X ZHANG; P FANG; Z PU; M LUO
• Keywords: Oxidation state

Abstract A series of CrO x –Y 2 O 3 catalysts were prepared by a deposition–precipitation method and tested for the fluorination of 2-chloro-1,1,1-trifluoroethane (CF 3 CH 2 Cl) to synthesize 1,1,1,2-tetrafluoroethane (CF 3 CH 2 F). The highest activity was obtained on a pre-fluorinated catalyst calcined at 400 °C, with 19% of CF 3 CH 2 Cl 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.