Aqueous-Phase Oxidation of N-Substituted N-PhosphonomethylGlycines into Glyphosate with Hydrogen Peroxide in the Presence of Carbon-Supported Gold Catalysts

Pavel A. Pyrjaev, Dmitry Yu Yushchenko, Boris L. Moroz, Zinaida P. Pai, Valerii I. Bukhtiyarov

Результат исследования: Научные публикации в периодических изданияхстатья

Аннотация

The catalytic performance of carbon-supported gold nanoparticles has been studied for the oxidative dealkylation of a series of N-substituted N-phosphonomethyl glycines into N-phosphonomethyl glycine (“glyphosate”) using dilute (0.11 m) aqueous H2O2 solution as oxidant. It was shown that the electron-donating inductive (+I) effect of the hydrocarbon substituent at the nitrogen atom greatly influences both the substrate reactivity and product distribution. Gold nanoparticles of 1.5-2.5 nm in diameter synthesized by “cationic adsorption” technique on the mesoporous Sibunit carbons, which are pre-oxidized with HNO3 and containing a lot of surface acidic groups, were found to catalyze the formation of glyphosate from N-isopropyl-N-phosphonomethyl glycine at 70 °C with selectivity up to 94% at 98% substrate conversion. Oxidation of other substrates containing the substituents with a weaker +I effect than that of iPr group resulted a large amount of undesirable N-decarboxymethylation product in addition to glyphosate. Considering the literature data and our own experimental results, assumptions about the reaction mechanism and causes of the observed trends are made.

Язык оригиналаанглийский
Страницы (с-по)10756-10764
Число страниц9
ЖурналChemistrySelect
Том4
Номер выпуска36
DOI
СостояниеОпубликовано - 30 сен 2019

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