Studies on the Ammoxidation of N-Heterocyclic Compounds. IV. Vapor-Phase Ammoxidation of Lutidine Isomers

Abstract

The kinetics of heterogeneous vapor-phase ammoxidation of lutidine isomers was studied over a Cr₂O₃-Al₂O₃ catalyst in a flow system. The reaction was carried out at atmospheric pressure and at a temperature of 360°. 3-Cyano-5-methylpyridine, 4-cyano-3-methylpyridine, 2-cyano-6-methylpyridine, 2-cyano-5-methylpyridine and 2-cyano-3-methylpyridine were produced selectively at low conversion from 3, 5-lutidine, 3, 4-lutidine, 2, 6-lutidine, 2, 5-lutidine and 2, 3-lutidine respectively. 2-Cyano-4-methylpyridine and 4-cyano-2-methylpyridine were produced in same amounts from 2, 4-lutidine. The reaction rate depended on the partial pressure of lutidine and oxygen. Experimental rate data were well interpreted by Langmuir-Hinshelwood mechanism, where the rate determining step was the surface reaction between adsorbed lutidine molecules and adsorbed oxygen molecules.