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Selective Dehydrofluorination of 1,1,1,3,3‐Pentafluoropropane to Synthesize Tetrafluoropropylene and Trifluoropropyne over the ZnO/Cr 2 O 3 Catalysts
Author(s) -
Jia Wenzhi,
Fang Xiuxiu,
Fang Chentao,
Hu Caihong,
Song Jiandong,
Luo Mengfei
Publication year - 2020
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.202002721
Subject(s) - catalysis , x ray photoelectron spectroscopy , crystallite , selectivity , chemistry , nuclear chemistry , raman spectroscopy , inorganic chemistry , crystallography , organic chemistry , chemical engineering , physics , optics , engineering
A series of ZnO/Cr 2 O 3 catalysts were prepared by an impregnation method, and the promoted role of ZnO on the activity for selective dehydrofluorination of 1,1,1,3,3‐pentafluoropropane (CF 3 CH 2 CHF 2 ) to tetrafluoropropylene (CFH=CHCF 3 and CH 2 =CFCF 3 ) and 3,3,3‐trifluoropropyne (CH≡CCF 3 ) was investigated. The ZnO/Cr 2 O 3 catalysts were characterized by XRD, Raman, BET, NH 3 ‐TPD and XPS. As more Zn was loaded, both the crystallite size of the Cr 2 O 3 and the surface area of catalysts both increased. The surface acidity of catalysts was the highest (1.02 μmol g −1 ) when 2 mol % of ZnO was added. Surface Cr species on the surface of ZnO/Cr 2 O 3 catalysts were identified, including Cr 2 O 3 , Cr(OH) 3 and CrO 3 . As the ZnO content increased, the relative content of Cr 2 O 3 elevated, while the relative contents of Cr(OH) 3 and CrO 3 decreased. It was found that the selectivities to four products (E−CFH=CHCF 3 , Z‐CFH=CHCF 3 , CH 2 =CFCF 3 and CH≡CCF 3 ) were greatly affected by the ZnO loading and reaction temperature. For the 2ZnO/Cr 2 O 3 catalyst, the lowest selectivities to E‐ and Z‐CFH=CHCF 3 were 61.2 and 15.7 %, respectively, while CH 2 =CFCF 3 and CH≡CCF 3 achieved the highest selectivity (11.7 % and 9.8 %, respectively) at 450 °C due to the highest surface acidity.