Method for the synthesis of n-phosphonomethyliminodiacetic acid

Abstract

A method for synthesis of N-phosphonoalkyliminodiacetic acid or derivatives thereof by forming a reaction mixture having an acid catalyst, a compound of the following general formula R—CH—NX—CH—Rand a compound having one or more P—O—P anhydride moieties to form a compound having a formula R—CH—N(—CHPOR)(—CH—R) wherein in R—CH—NX—CH—R: X is —CH—OH or —CH—COOH; Rand Rare independently selected from the group consisting of nitrile, C-Calkyl carboxylate, and carboxylic acid for when X is —CH—OH, or Rand Rare both carbonyl groups linked by a hydrogen substituted nitrogen atom or a C-C-alkyl substituted nitrogen atom; and Ris H, an alkyl group, or an aryl group; the anhydride moieties in the P—O—P anhydride compound have one P atom at the oxidation state (+III) and one P atom at the oxidation state (+III) or (+V); and 2) hydrolyzing the mixture to form N-phosphonomethyliminodiacetic acid or one of its derivatives.