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Purifying 2,3-pyridine-dicarboxylic acid used as intermediate for e.g. drugs, by treatment in solution with sulfur source, removal of precipitate and precipitation with acid, giving low heavy metal content
Purifying 2,3-pyridine-dicarboxylic acid used as intermediate for e.g. drugs, by treatment in solution with sulfur source, removal of precipitate and precipitation with acid, giving low heavy metal content
Production of 2,3-pyridine-dicarboxylic acid (I) having a reduced heavy metal content comprises: (a) adding at least one sulfur source comprising hydrosulfides, sulfides, polysulfides or sulfur, to a solution of (I) or its salts; (b) removing the obtained precipitate from the solution; (c) acidifying the solution with mineral acid, and (d) recovering the precipitated (I).
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