Kinetics and mechanism of oxidation of allyl, crotyl and prop argyl alcohols by diperiodato cuprate(III) in alkaline medium

Abstract

The kinetics and mechanism of oxidation of ɑ, <em>β</em>-unsaturated alcohols (UA) such as allyl, crotyl and propargyl alcohols by periodate complex of trivalent copper in aqueous alkaline medium has been studied spectrophotometrically at 416 run. The order in [oxidant] and [substrate] is found to be unity each. The rate decreases with increase in [periodate] and increases with increase in [OH^-]. There is no effect of addition of salts like Na₂SO₄ and KNO₃. The primary kinetic isotopic effect <em>k</em><img src='http://www.niscair.res.in/jinfo/equation88.gif' border=0><em>/ k<img src='http://www.niscair.res.in/jinfo/equation89.gif' border=0></em> is 3.87 at 313 K. The solvent isotopic effect <em>k</em><em>/ k</em> is 0.912 at 313 K. The product of oxidation has been identified as the corresponding aldehyde. Participation of double bond in the oxidation reaction has not been observed. Under the experimental conditions monoperiodato cuprate(III) species has been assumed to be the active species. The results are discussed in terms of + I effect of methyl group and resonance stabilisation of free radical. The observed results are explained in terms of an outersphere electron transfer mechanism.