The oxidation of methyl phenyl sulfide in water and water-alcohol mixtures takes place both by a noncatalytic mechanism and with the participation of hydrogen peroxide as catalyst; in the presence of ammonium hydrocarbonate it takes place by a mechanism involving HCO 4 − as a more active oxidant than hydrogen peroxide (>100 times). In water-alcohol media (ethylene glycol, isopropyl alcohol, tert-butanol) the rate decreases in the order H 2 O > EG > IPA > TBA. The reactivity of organic sulfides varies in the following way: MeSPh ≈ EtSPh << Et 2 S. The results were interpreted from the standpoint of a molecular mechanism of oxidation of the sulfide with H 2 O 2 and HCO 4 − through a polar transition state, containing the HOX molecule (X = H, OH, OR) as acid-base catalyst.Recent interest in investigation of the oxidation of organic sulfides arises from the fact that these processes are regarded as the most satisfactory model of the decomposition of ecotoxicants (pesticides) and the active components of chemical weapons; models of yperite are investigated more often than others [1][2][3][4]. Of great interest from the standpoint of the creation of so-called "green" technologies for protection of the environment are systems based on hydrogen peroxide. In weakly alkaline media they can act as a mild oxidant in the un-ionized form [1,4] and as an effective α-nucleophile in the form of the HO 2 − anion [5]. The problem of the low solubility of organic substrates, important for the development of green technologies, is solved by conducting the nucleophilic oxidation reactions in aqueous solutions of surfactants (micellar catalysis) [6-8] and also in microemulsions [9, 10] and water-alcohol mixtures [1,4,8,11]. In oxidation processes hydrogen peroxide is usually activated by various acids, transforming it into highly reactive peroxy acids. Particularly attractive among the activators are hydrocarbonates as readily obtainable and ecologically safe compounds exhibiting maximum activating effect in a weakly alkaline medium [1,4,7,8,11].The reactivity of a series of sulfides in water-alcohol media [1,4,11] and also in the presence of surfactants [7,8] was recently investigated in the H 2 O 2 /OH -and H 2 O 2 /OH -/HCO 3 − systems. In the present work the kinetics of oxidation of methyl phenyl sulfide (MPS) by hydrogen peroxide was investigated both in the absence and in the presence of ammonium hydrocarbonate as activator in water and in water-alcohol mixtures [30 vol.% of the alcohol: isopropyl alcohol (IPA), tert-butyl alcohol (TBA), and ethylene glycol (EG), at 25°C]. The choice of the given sulfide as subject of investigation was determined by the fact that compared with our previously investigated diethyl sulfide [4, 8] it is a model closer to yperite both in 98 0040-5760/05/4102-0098
Вивчено нуклеофільне розщеплення метилпаратіона НОО-аніоном, що генерується з пероксисольвата карбаміду у присутності бікарбонату амонію та борної кислоти. Виявлена супернуклеофільна реакційна здатність аніону діпероксоборату 2 2 B(OH) (OOH). Показана можливість використання твердих джерел пероксиду водню в деконтамінаційних системах. Визначено величину α-ефекту (k HOO-/k НО-), яка вказує на аномально високу реакційну здатність HOO-аніона в розкладанні фосфорних ефірів Ключові слова: нуклеофільне заміщення, пероксид водню, пероксисольват карбаміду, метилпаратіон, пероксоборат, пероксокарбонат Изучено нуклеофильное расщепление метилпаратиона НОО-анионом, генерируемым из пероксисольвата карбамида в присутствии бикарбоната аммония и борной кислоты. Обнаружена супернуклеофильная реакционная способность аниона дипероксобората 2 2 B(OH) (OOH). Показана возможность использования твердых источников пероксида водорода в деконтамінаційних системах. Определена величина α-эффекта (k HOO-/k НО-), которая указывает на аномально высокую реакционную способность НОО-аниона в разложении фосфорных эфиров Ключевые слова: нуклеофильное замещение, пероксид водорода, пероксисольват карбамида, метилпаратион, пероксоборат, пероксокарбонат
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