The kinetics of vapour-phase ammoxidation of 2,6-dichlorotoluene over VPO catalyst

The kinetics of the vapour-phase ammoxidation of 2,6-dichlorotoluene (DCT) to 2,6-dichlorobenzonitrile (DCBN) over a vanadium phosphorus oxide (VPO) catalyst was investigated. In this paper, the main focus is on developing a mathematical model to describe the reaction kinetics of ammoxidation of DCT in a nonisothermal fixed-bed lab-scale reactor. The effect on catalytic performance of various operating parameters, including reaction temperature and contact time, as well as of DCT, NH3, O2, and H2O partial pressures, were studied. The experimental kinetic data obtained under nonisothermal conditions were correlated by the rate equations based on the Langmuir–Hinshelwood mechanism. All of the possible routes of reaction scheme were considered. Finally, the derived kinetic model was validated by comparing experimental results obtained in up-scaled experiments from a mini-plant with that of simulated results. The simulated values of various parameters, including the conversions of DCT and O2 and even the yields of DCBN and COx, agree well with those of experimentally measured values.