A process for the preparation of 2,6-dihydroxybenzoic acid

Abstract

This invention discloses a method for preparing 2,6-dihydroxybenzoic acid. Specifically, this invention uses resorcinol as a starting material, which reacts with hydrogen and formic acid derivatives (supported metals such as ruthenium, rhodium, palladium, platinum, iridium, and nickel) under the action of a catalyst to efficiently generate 1,3-cyclohexanedione. 1,3-cyclohexanedione then reacts with carbon dioxide under the action of a base to generate a carboxylic acid intermediate; this reaction exhibits specific regioselectivity. The carboxylic acid intermediate undergoes dehydrogenation aromatization under the action of a catalyst (supported metals such as ruthenium, rhodium, palladium, platinum, iridium, and nickel) to generate 2,6-dihydroxybenzoic acid. This invention exhibits specific regioselectivity, generating only the desired 2,6-dihydroxybenzoic acid, avoiding the generation of 2,4-dihydroxybenzoic acid byproducts reported in current literature. Compared with existing technologies, this invention has advantages such as simplicity, high selectivity, high atom economy, high yield, green and pollution-free operation, and ease of industrialization.

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