Oxidation of 2,5-dimethylpyrazine with oxygen in the vapor phase on oxide catalysts and in the liquid phase in the presence of bases
The vapor-phase oxidation of 2,5-dimethylpyrazine with oxygen on vanadium-molybdenum oxide catalysts modified with silver oxide gives 5-methyl-2-formylpyrazine and 2,5-diformylpyrazine in 37% and 35% yields, respectively. Pyrazine-2,5-dicarboxylic acid was obtained in 53% yield by the liquid-phase oxidation of 2,5-dimethylpyrazine with oxygen in the presence of a strong base and an interphase catalyst.