The oxidation of thioanisole, PhSMe, by tetraperoxomolybdate dianion, Mo(O2)42-, is mediated by cationic micelles of cetylpyridinium chloride, CPyCl. Concentration of reactants in the micellar pseudophase accelerates reaction, but the local second-order rate constant is lower in micelles than in water:tert-butyl alcohol (7:3 v/v), and except with dilute CPyCl, the overall reaction is micellar inhibited. The sulfoxide formed in the initial oxidation is only slowly oxidized to sulfone. The association equilibrium constant between the tri- and tetra-peroxomolybdates increases in the sequence H2O < H2O:t-BuOH < CPyCl micelles, but the forward and reverse rate constants decrease in this sequence due to changes in water contents of these reaction media. These oxidations are carried out at pH 9−10 where phosphonofluoridates and activated phosphate esters undergo overall peroxydolysis and these systems can potentially decontaminate toxic chlorosulfides and phosphonofluoridates.
The Oxidation of Thioanisole by Peroxomolybdate in Micelles of Cetylpyridinium Chloride
CHIARINI, MARCO;
2002-01-01
Abstract
The oxidation of thioanisole, PhSMe, by tetraperoxomolybdate dianion, Mo(O2)42-, is mediated by cationic micelles of cetylpyridinium chloride, CPyCl. Concentration of reactants in the micellar pseudophase accelerates reaction, but the local second-order rate constant is lower in micelles than in water:tert-butyl alcohol (7:3 v/v), and except with dilute CPyCl, the overall reaction is micellar inhibited. The sulfoxide formed in the initial oxidation is only slowly oxidized to sulfone. The association equilibrium constant between the tri- and tetra-peroxomolybdates increases in the sequence H2O < H2O:t-BuOH < CPyCl micelles, but the forward and reverse rate constants decrease in this sequence due to changes in water contents of these reaction media. These oxidations are carried out at pH 9−10 where phosphonofluoridates and activated phosphate esters undergo overall peroxydolysis and these systems can potentially decontaminate toxic chlorosulfides and phosphonofluoridates.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
