III International Conference

PP-II-125THE MECHANISM OF COPPER COMPLEXES’ CATALYTIC ACTION IN THELIQUID PHASE THIOL OXIDATIONSmirnov V.V., Tarkhanova I.G., Gantman M.G.Lomonosov Moscow State University, Department of Chemistry, Moscow, RussiaE-mail: Mike_Gantman@mail.ruThe nature of mono- and polyfunctional donor compounds influences the rate ofmercaptan catalytic oxidation in non-polar media in the prescense of individual andheterogenized copper complexes greatly [1]. The conversion of dodecanethiol tocorresponding disulfide in the i-octane at room temperature was studied as the test reaction.Nitrogen-, sulfur- and phosphorous-containing compounds were used as donors. StrongLewis’ bases (for example, aromatic amines and aminoalcohols) were found to inhibit theprocess. For instance, the mentioned compounds supress the activity of homogenous systemson the basis of divalent copper. The activity of heterogeneous systems decreased to a lesserdegree. Aromatic amines and aminoalcohols (benzylamine, 1-phenyl-3-(N-methyalamino)-propanol-3, 1-phenyl-2-(N-methylamino)-etyhanol)) were established by the use of UV- andESR- spectroscopy to stabilize divalenet copper ions and impede agreeably its reduction tocopper thiolate — an important step of thiol oxidation. The inhibitory action of weak Lewis’bases (e.g. triphenylphosphine) can accounted for by the univalent copper stabilization andagreeably by the deceleration of metal ion oxidation. The best donors, rising the catalyticactivity of coppercontaining ctalysts turned out to bemonoethanolamine>benzylamine>ammonia>cyclohexylamine. In the presence of thementioned compounds in the system, containing the catalyst, dodecanethiol and the dissolverboth univalent and divalent copper ions were observed.In accordance with generally accepted mechanism on the first stage of the reaction thedivalent copper is reduced copper (I) thiolate. We have established, that copper thiolate is notactive in the thiol oxidation. Even after the addition of donor compounds the reactionproceeds much slower than in the case of individual copper complexes’ use.The mechanism of the investigated donors’ in homogeneous systems promoting actionhas been considered and the comparative analysis of their role in homogeneous andheterogeneous processes has been carried out.References1. Konovalov A.V., Smirnov V.V., Tarkhanova I.G., Euroasian patent #005122, 30.12.2004393