Akademik Veri Yönetim Sistemi
INTERNATIONAL JOURNAL OF CHEMICAL KINETICS, cilt.29, sa.5, ss.359-366, 1997 (SCI-Expanded)
Effect of some tert-amines on the catalytic osmium tetroxide dihydroxylation of cyclohexene in aqueous Levi-butyl alcohol has been investigated. All amines have been found to retard the catalysis greatly and beyond a definite concentration of amine, the rate reaches a minimal and remains constant. The oxidation of cyclohexene is inhibited by pyridine, 2,2'-bipyridyl, and DABCO with an inverse first-order dependence whereas inhibition by triphenylamine, N,N-diethylaniline, picoline, pyrazine, hexamethylenetetraamine, and TMEDA shows an inverse partial order dependence. The involvement of dioxomonoglycolatoosmium(VI) esters and their monoamine adducts in the rate determining oxidation step was established by the linear plots of 1/Delta k(2) vs. 1/[L] where Delta k(2) is the decrease in the second-order rate constant in the presence of [L] concentration of tert-amine. The ligand-accelerated or ligand-decelerated catalysis of tert-amines in the catalytic osmium tetraoxide dihydroxylation of alkenes may vary depending on the secondary oxidant, on the alkene, and on the structure and concentration of the tert-amine. (C) 1997 John Wiley & Sons, Inc.