The Kolbe-Schmitt Reaction in Aqueous Solutions.

Abstract

The carboxylation of m-aminophenol with potassium hydrogencarbonate in aqueous solutions has been studied kinetically. The formation of 4-hydroxyanthranilic acid (4HAA) has been found for the first time in the carboxylation of m-aminophenol which gives only p-aminosalicylic acid (pAS) in the usual Kolbe-Schmitt reaction. Since 4HAA was easily decarboxylated, the product was removed from the reaction mixture after the carboxylation for 1 h at 60 °C. This method was repeated three times and 4HAA was obtained as a major product in 30.2% yield.