Catalytic dehydrofluorination of 1,1,1,3,3-pentafluoropropane to 1,3,3,3-tetrafluoropropene over fluorinated NiO/Cr2O3 catalysts

摘要

Catalytic dehydrofluorination of 1,1,1,3,3-pentafluoropropane to 1,3,3,3-tetrafluoropropene was performed on a series of fluorinated NiO/Cr2O3 catalysts. The NiO/Cr2O3 catalysts were more active than the Cr2O3 because the new acid sites provided by NiF2 had higher turnover frequencies (9.43 x 10(-3) - 12.08 x 10(-3) s(-1)) than those on the Cr2O3 (4.55 x 10(-3) s(-1)). Also, the NiO/Cr2O3 was more stable than the Cr2O3 due to its lower density of surface acid sites, which alleviated the coke deposition on the catalyst as evidenced by the Raman spectroscopic results. The kinetic results revealed that the 15NiO/Cr2O3 had much lower activation energy (63.6 +/- 4.5 kJ mol(-1)) than the Cr2O3 (127.6 +/- 3.8 kJ mol(-1)). Accordingly, different reaction pathways on the two catalysts were proposed, which involved the cleavage of the C-F and C-H bonds on the surface acid and base sites, respectively. (C) 2017 Elsevier B.V. All rights reserved.