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A DFT-assisted mechanism for evolution of the ammoxidation of 2-chlorotoluene (2-CLT) to 2-chlorobenzonitrile (2-CLBN) over alumina-supported V2O5 catalyst prepared by a solution combustion method

Author:
Dwivedi, Ritambhara, Sharma, Prabhakar, Sisodiya, Akrati, Batra, Manohar Singh, Prasad, Rajendra
Source:
Journal of catalysis 2017 v.345 pp. 245-257
ISSN:
0021-9517
Subject:
Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, ammonia, catalysts, combustion, imines, moieties, oxygen, surface area, temperature
Abstract:
Ammoxidation of 2-chlorotoluene (2-CLT) has been carried out over vanadates and supported vanadates in the temperature range 350–450°C. The catalysts were characterized by XRD, XPS, FT-IR, and Raman and surface area measurement. A maximum yield of 76% of 2-CLBN was obtained at a temperature of 425°C and a 2-CLT:NH3:air mole ratio of 1:8:22. DFT computations suggest that the reaction follows a Mars–van Krevelen (MVK) type of redox mechanism. The catalyst is first reduced by ammonia, producing an imine species. The 2-CLT molecule is also adsorbed through a vanadyl oxygen to produce a CH2C6H5 species. This moiety is adsorbed over the catalyst through an imine formed on the surface to produce 2-chlorobenzonitrile. XPS spectra of fresh and spent catalysts confirm reduction of the catalyst during ammoxidation.
Agid:
6092740