Process for producing pyridine carboxylic acids

A process for preparing pyridine carboxylic acid, the process comprising:

• oxidizing alkyl pyridine with oxygen and/or air in presence of water and a vanadia based catalyst, and
• isolating the pyridine carboxylic acid,
• wherein the said catalyst comprises pellets of an oxide of vanadium with oxide of titanium as a support and oxide of metalloid as an additive and wherein the said catalyst pellets are packed in a reactor in a multilayer arrangement, wherein the catalyst includes pellets having x(V2O5)-y(TiO2)-z(MaOb), where x=5-40% by weight, y=95-60% by weight, z=1-10% by weight and M is the metalloid additive.