کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
62529 | 47644 | 2008 | 10 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Effect of calcination temperature on CrOx–Y2O3 catalysts for fluorination of 2-chloro-1,1,1-trifluoroethane to 1,1,1,2-tetrafluoroethane Effect of calcination temperature on CrOx–Y2O3 catalysts for fluorination of 2-chloro-1,1,1-trifluoroethane to 1,1,1,2-tetrafluoroethane](/preview/png/62529.png)
A series of CrOx–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 CrOx species was investigated. X-ray diffraction and Raman results indicated that the CrOx 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 CrOx 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 CrFx, CrOxFy or Cr(OH)xFy phases originated from high oxidation state Cr(VI) species were the active sites for the fluorination reaction.
Journal: Journal of Catalysis - Volume 253, Issue 1, 1 January 2008, Pages 1–10