The Kinetics of the Vapor-Phase Ammoxidation of <i>m</i>-Xylene over a Vanadium Catalyst

Abstract

Abstract The kinetics of the vapor-phase ammoxidation of m-xylene and m-tolunitrile over a vanadium oxide catalyst were studied in a flow system. The reaction rate data obtained were correlated by the rate equation based upon the Langmuir-Hinshelwood mechanism, where the adsorption of m-xylene was strong. From the result of the experiments it was suggested that the reaction scheme consisted of four parallel routes: (1) the step-by-step ammoxidation of m-xylene to isophthalonitrile via m-tolunitrile; (2) the direct ammoxidation to isophthalonitrile from m-xylene; (3) the formation of carbon oxides and hydrogen cyanide via m-tolunitrile and (4) the direct formation of carbon oxides and hydrogen cyanide from m-xylene. The activation energies for the reaction of m-xylene and m-tolunitrile were 43.7 and 31.2 kcal/mol respectively in the range from 396 to 420°C.