(The) gas phase ammoxidation of toluene to benzonitrile on $V_2O_5-Cr_2O_3$ catalyst

Abstract

Preparation of benzonitrile by ammoxidation of toluene in vapour phase was studied in a fixed bed catalytic reactor. $V_2O_5-Cr_2O_3$ unsupported catalysts with the mole ratio of 1:1, 2:1, 4:1, and 9:1 were used in this study. $V_2O_5-Cr_2O_3$(4:1 in mole ratio) catalyst was found to be the catalyst of the highest activity and selectivity under a constant feed rate of air, ammonia and toluene at $440\,^\circ\!C,\; 470\,^\circ\!C,\; 500\,^\circ\!C$ and $520\,^\circ\!C$, respectively. The effect of the mole ratios of air to toluene and ammonia to toluene on $V_2O_5-Cr_2O_3$(4:1 in mole ratio) catalyst was also investigated. The optimum mole ratios of air to toluene and ammonia to toluene were found to be 43.2 and 14.5, respectively, at $520\,^\circ\!C$. Ammoxidation of p-chlorotoluene, m-chlorotoluene, m-tolunitrile and m-methylanisole was also examined on $V_2O_5-Cr_2O_3$(4:1 in mole ratio) catalyst under a constant feed rate of air, ammonia and substrates at $520\,^\circ\!C$.