One-step selective synthesis of 2-chlorobenzonitrile from 2-chlorotoluene via ammoxidation

Abstract

A series of V2O5/Al2O3 catalysts were prepared by a wet impregnation method and employed for a one-step synthesis of 2-chlorobenzonitrile from 2-chlorotoluene via ammoxidation in a fixed bed reactor at atmospheric pressure. The catalysts were characterized by BET-SA, XRD,FT-IR, TPR, UV-Vis DRS and NH3-TPD to identify the molecular structural changes of the catalysts. The characterization results revealed that the addition of V2O5 to Al2O3 amplified the crystallinity of alumina and also resulted in the formation of an interactive species i.e. AlVO4. Most of the V2O5 existed in the form of isolated surface and polymeric tetrahedral vanadia species in a highly dispersed state and/or having a strong interaction with the support. The formation of different kinds of vanadia species was entirely dependent on the content of vanadia present in the catalyst. A 10 wt% V2O5/Al2O3 catalyst was found to be the best and the high selectivity for 2-CBN was presumably due to the formation of the isolated surface and polymeric tetrahedral vanadia species along with aluminum vanadate species.