| abstract |
A method for producing 2,6-dihydroxybenzoic acid from an aqueous solution which contains a mixture of 2,6-dihydroxybenzoic acid and 2,4-dihydroxybenzoic acid, preferably of concentration 5 to 30 wt%, e.g. obtained by carboxylation of resorcin in water and/or an organic solvent, by adjusting the pH value to 4 or more, preferably 4 to 9, and heating the mixture to selectively decompose 2,4-dihydroxybenzoic acid, and separating 2,6-dihydroxybenzoic acid from the decomposition reaction mixture, e.g. by acid-precipitation and filtration. n The product is obtained in high purity, e.g. at least 98 wt%, and is useful as a starting material in industrial synthesis. |