Oxidation of some primary alcohols by N-bromoacetamide in acidic media by using chloro complex of Rh (III) as catalyst

Abstract

Kinetics of oxidation of two of primary alcohols by N-bromoacetamide (NBA) has been studied in acidic medium using chloro complex of Rh(III) as homogeneous catalyst. The reaction shows first order kinetics with respect to NBA and alcohols concentrations, The reaction also shows first order kinetics with respect to Rh(III) concentration and fractional order with respect to [H⁺]. Invers fractional order with respect to [Acetamide] was obtained in Rh(III) catalysed oxidation of alcohols. Variation of ionic strength, dielectric constant and chloride ion of the medium has no effect on the rate of oxidation. H₂OBr⁺ and [Rh(H₂O) Cl₅]^-2 have been suggested to be the reactive species of NBA and Rh(III)chloride in acid medium. The rates were determined at four different temperatures and the activation parameters were evaluated. A mechanism involving formation of hypobromite ester in the rate determining step has been proposed. The main oxidation products of the reactions have been identified as aldehyde