MECHANISTIC INVESTIGATION OF OXIDATION OF ALDONITRONES BY IMIDAZOLIUM DICHROMATE IN AQUEOUS ACETONITRILE. A KINETIC STUDY

作者：George S; Pichai R; Manikandan G; Rajarajan G; Jayabharathi J; Thanikachalam V^*

来源：Oxidation Communications, 2010, 33(2): 345-355.

• nitrones
• imidazolium dichromate
• isokinetic temperature
• the Hammett plot
• the Exner plot

The oxidation of 12 monosubstituted aldonitrones by imidazolium dichromate (IDC) in acetonitrile-water (ACN-H(2)O) mixture leads to the formation of the aldehyde and nitrosobenzene. The reactions was first order each with respect to [oxidant] and [nitrone]. The reaction rate increases with increase in [H(+)] and fractional order dependence with respect to acid was observed. The rate of reaction was enhanced by the addition of oxalic acid and decreased with increasing concentration of manganous sulphate, 2,2'-bipyridyl and 1,10-phenanthroline. Electron-withdrawing substituents retard the reaction rate and electron-releasing substituents were found to increase the rate and the rate data obey the Hammett relationship. The enthalpy and entropy of activations were linearly related. The isokinetic temperature is found to be 348 K. A mechanism involving the formation of protonated species of nitrone, which react with IDC in the rate-determining step, has been proposed.

• 出版日期2010