Oxidative ammonolysis of 3(4)-methyl- and 3,4-dimethylpyridines using vanadium oxide catalysts

Oxidative ammonolysis of 3(4)-methyl- and 3,4-dimethylpyridines using vanadium oxide catalyst doped with Cr2O3, SnO2, and ZrO2 was studied. The yields of nitriles and conversion of the starting compounds were found to depend on the CH-acidity of the latter in the gas phase. The possible mechanisms of the formation of pyridine-3,4-dicarboxylic acid imide at the oxidative ammonolysis of 3,4-dimethylpyridine was discussed. The relation between the activity of the modified catalysts and the proton affinity of the vanadyl oxygen calculated by the extended Huckel method was established.