A method for the production of 2,3 - pyridine dicarboxylic acid (process of producing 2,3 - pyridinedicarboxylic acid)

摘要

Highly pure 2,3 - pyridine dicarboxylic acid is prepared according to a method for the use in the commercial production with high yield and with the recycling of spent liquor is suitable in the circuit. The method comprises the steps of: (a) oxidation of quinoline or 8 - hydroxyquinoline in a solvent in the presence of copper (ii) - ions with precipitation of the copper (ii) salt of 2,3 - pyridine dicarboxylic acid and then removal of the precipitates, (b) reacting of the separated copper (ii) salt with an alkali in a solvent, so that a solution of an alkali metal salt of 2,3 - pyridine dicarboxylic acid is obtained, and (c) reacting the solution of the alkali metal salt with a mineral acid with precipitation of 2,3 - pyridine dicarboxylic acid and then removal of the precipitates, and is characterized in that (a) a part or the entire solution, which is obtained after the precipitated 2,3 - pyridine dicarboxylic acid in step (c) has been separated, at least as a part of the solvent in step (a) or (b) is used, or (b) copper or a copper compound to the solution is provided, which are obtained, after the precipitated 2,3 - pyridine dicarboxylic acid in step (c) has been separated, wherein the in the solution remaining 2,3 - pyridine dicarboxylic acid in the form of its copper (ii) salt is becoming.