N-phosphonomethyl iminodiacetic acid N-oxide synthesis in the presence of bifunctional catalysts based on tungsten complexes

摘要

N-phosphonomethyl iminodiacetic add (PMIDAA) was oxidized in a two phase liquid system by 32% hydrogen peroxide at 70 degrees C. Reaction was performed in the presence of tungsten oxo- and peroxo- complexes, containing N-hexadecylpyridinium or quaternary ammonium cation. Substrate conversion and N-oxide PMIDAA selectivity were found to depend on anions structure and quaternary nitrogen containing cation properties. The best results were obtained when PMIDAA was oxidized in the presence of N-hexadecylpyridinium tetra(oxodiperoxotungsto)phosphate, substrate conversion being 99%, and target product selectivity being 97%. (C) 2015 Elsevier B.V. All rights reserved.