In situ Raman spectroscopy studies on chromium oxide catalyst in an anhydrous hydrogen fluoride atmosphere

✍ Scribed by Liqiong Xing; Qingyuan Bi; Yuejuan Wang; Ming Guo; Jiqing Lu; Mengfei Luo

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 242 KB
• Volume: 42
• Category: Article
• ISSN: 0377-0486
• DOI: 10.1002/jrs.2811

✦ Synopsis

Abstract

Changes of different chromium oxide species [Cr(VI), Cr(V) and Cr(III)] were investigated using in situ Raman spectroscopy in an anhydrous hydrogen fluoride (AHF) atmosphere. It was found that the Cr(VI) (CrO~3~) and Cr(V) (YCrO~4~) species were easy to fluorinate, and generated CrO~2~F~2~ or/and CrOF~3~, while the Cr(III) (Cr~2~O~3~) species was difficult to fluorinate. Moreover, the CrO~2~F~2~ and CrOF~3~ species were stable in the AHF atmosphere, but they easily transform into CrO~3~ in N~2~ atmosphere and further decomposed to Cr~2~O~3~ at 400 °C. Moreover, Cl/F exchange reaction of CF~3~CH~2~Cl to CF~3~CH~2~F over these Cr species indicated that the high‐oxidation‐state CrO~x~F~y~ (CrO~2~F~2~ and CrOF~3~) species exhibited much higher reactivities than Cr~2~O~3~, suggesting that these species (CrO~2~F~2~ and CrOF~3~) may be the active phases of the reaction. Copyright © 2010 John Wiley & Sons, Ltd.