Substituent Effects in the Oxythallation of Alkenes*

where R = H and/or alkyl (aryl). Presence of electron-releasing substituents on alkene double bond increases the rate of oxythallation it is in accordance with Ads character of this reaction [2-5]. In earlier papers of this series we showed that oxidation of alkenes by an aqueous solution of thallic salts suits Taft's equation, and isokinetic relationship, too [6-8]. We studied the enthalpy entropy relationship in this reaction and we found that the oxidation of alkenes by thallic salts was the case, where both activation parameters were variable in the sense that their effects partially compensate each other [8, 9]. The determination of structure effects in oxidation was carried out using linear free energy relationship and it was found that polar effects were the most important for the oxidation of RCH = CH2 and R!R2C = CH2 alkenes while both steric and resonance effects were important in the oxidation of internal alkenes [6]. This paper concerns itself with the examination of the response of rate of oxythallation to changes in ionization potentials for a series of substituated alkenes.