| 摘要 |
<p>PROBLEM TO BE SOLVED: To enable the production of a pyridinecarboxylic acid of high quality through the liquid phase oxidation of an alkylpyridine using a catalyst and a bromine-containing compound by smoothly circulating the oxidation product solution containing the catalyst without large change of catalyst conditions and addition of a large amount of the bromine component. SOLUTION: An alkylpyridine is liquid-phase oxidized in the presence of a catalyst comprising a heavy metal and bromine in a lower aliphatic monocarboxylic acid as a solvent with an oxygen-containing gas at 150-250 deg.C under a pressure of 10-30kg/cm<2> G to give a pyridinecarboxylic acid. At this time, the reaction product solution of the liquid-phase oxidation is catalytically hydrogenated in the presence of a metal of group VIII (for example, Pd on activated carbon) at 100-250 deg.C under a hydrogen partial pressure of 1-80kg/cm<2> G, the pyridinecarboxylic acid is separated and the remaining reaction product solution is reused in the following oxidation. The heavy metal for the catalyst is, for example, cobalt acetate, while the bromine compound is, for example, hydrobromic acid. Pyridinecarboxylic acid is useful as a raw material for feed additives and medicines.</p> |
