Sodium ruthenate catalysis in the oxidation of substituted benzyl alcohols by hexacyanoferrate(III)

Abstract

Ru(VI) catalysis in the oxidation of benzyl alcohol and its monosubstituted analogues by hexacyanoferrate(III) [Fe(III)]in <em>t</em>-butanol (25%, v/v) in alkaline medium has been studied. The reaction is first order in [Ru(VI)], fractional order in [alcohol] and zero order each in [Fe(III)], [base] and [<em>t</em><em> - </em>butanol]. The primary kinetic isotopic effect (<em>k</em>_H/<em>k</em>_D) is 4.12 at 298 K. The solvent isotopic effect (<em>k</em>_{<img src='http://www.niscair.res.in/jinfo/equation88.gif' border=0>}/<em>k</em>_{<img src='http://www.niscair.res.in/jinfo/equation89.gif' border=0>}) is 0.948 at 298 K. The reaction exhibits a reaction constant <em>ρ </em>of - 0.540 at 298 K. A mechanism involving the transfer of a hydride ion to the oxidant is suggested. The activation enthalpies and entropies are linearly related.