Method of producing 1,4-dihydroxy-2-naphthoic acid.

摘要

A method of producing 1,4-dihydroxy-2-naphthoic acid comprises: subjecting 1,4-dihydroxynaphthalene to alkali metal salt formation reaction at a temperature of 110 DEG C or more in an organic medium capable of dissolving 1,4-dihydroxynaphthalene, preferably selected from ketones, esters, monoalcohols, polyhydric alcohols and derivatives thereof and aromatic hydrocarbons using an alkali metal alcoholate, preferably of a Cl-4 alcohol; and subjecting the salt formation reaction mixture to carboxylation using carbon dioxide gas under atmospheric or increased pressure and preferably with an excess of CO2 of 1.5 mols or more per mol of the dihydroxynaphthalene. The product is obtained easily and in a high yield, e.g of 80 to 92% and in high purity, and is useful as an intermediate for dyes, pigments and photographic agents.