Hydrogen abstraction perchlorate

Olaj, 1987]. Thus initiation in the presence of perchlorate ion proceeds by oxidation of perchlorate followed by hydrogen abstraction ... 

It has been known that the electrolysis in an MeCN- NaClO system generates an acid The hydrogen has to originate from the solvent. A mechanism for hydrogen abstraction from acetonitrile by the electrooxidatively generated radical 104- to produce perchloric acid has been proposed, but no evidence for the succinonitrile formation appeared (Eq. (5)). The detection of the 104- radical by the aid of HSR was tried But it was found to be difficult to differentiate between the perchlorate radical and the radical from chlorine dioxide The electrolysis in a CH Clj—... 

Miscellaneous Cyclohexanes. Various reactions involving hydroxylation of cyclohexane derivatives have been reported. The reaction of cyclohexanol with Fe(C10 )2 and hydrogen peroxide in acidic aqueous MeCN solutions has been shown to be very sensitive to the exact concentrations of Fe", Fe ", and perchloric acid. In MeCN, cis-cyclohexane-l,3-diol forms 72% of the product diol, i.e. hydrogen removal at C-3 occurs with some stereoselectivity cis to the hydroxy-group. In highly aqueous solutions, the dominant oxidation site is at C-4. Evidence is presented for a stepwise process involving an initial directed hydrogen abstraction, oxidation of the radical by Fe" , and stereoselective carbonium ion capture. 

Triphenylcarbonium perchlorate Hydrogen abstraction by triphenylcarbonium perchlorate J2-5-Oxazolones... 

Typical non-enolising aldehydes are formaldehyde and benzaldehyde, which are oxidised by Co(III) Ce(IV) perchlorate and sulphate , and Mn(III) . The main kinetic features and the primary kinetic isotope effects are the same as for the analogous cyclohexanol oxidations (section 4.3.5) and it is highly probable that the same general mechanism operates. kif olko20 for Co(III) oxidation of formaldehyde is 1.81 (ref. 141), a value in agreement with the observed acid-retardation, i.e. not in accordance with abstraction of a hydroxylic hydrogen atom from H2C(OH)2-The V(V) perchlorate oxidations of formaldehyde and chloral hydrate display an unusual rate expression, viz. 

The perchlorate or tetrafluoroborate salt of the trityl cation abstracted the hydride ion from trisubstituted cyclopropenes 1 bearing a tertiary hydrogen to give the corresponding cyclopropenylium salts 2. The reaction was usually conducted in polar solvents, such as acetonitrile or dichloromethane, at room temperature under protection from moisture. Addition of a nonpolar solvent such as diethyl ether resulted in precipitation of the formed cyclopropenylium salts. " ... 

The results were different in one important respect from the earlier ones for photolysis of Fe(III) complexes in solution. The Fe(II) yield here showed very little dependence on t-butanol concentration and indicated a primary quantum yield of 0.170, approximately half the extrapolated intercept for methanol of 0.330. In ferric perchlorate photolysis studied earlier, both alcohols gave a common extrapolated yield equal to the independently determined primary yield for hydroxyl radical production. In other words, at the TiOa surface we appear to generate more "OH radical for reaction with CHaOH than "OH radical" to react with t-butanol. From these results, we infer that a hole reaching the anatase surface may produce one of two distinct oxidants in approximately equal quantity. These are a species capable of abstracting hydrogen (e.g. the OH radical) and a second less reactive oxidant. Preliminary results from parallel experiments... 

The rates of hydrolysis of monomeric ruthenium(n) chloride complexes which are generated electrochemically have been reported and are much more rapid than those observed for the corresponding ruthenium(m) species. It is suggested that Ru chloride complexes may exist as unstable intermediates when the ruthenium(iii) species are reduced. Ruthenium(n) dimethyl sulphoxide complexes have been shown to be the products of refluxing the hydrated ruthenium(iii) chloride with DMSO. The use of ruthenium tetroxide as an oxidant has also been described. In the oxidation of tetrahydrofuran in aqueous perchloric acid, an inverse hydrogen-ion dependence is observed, the proposed mechanism involving hydride abstraction with recombination to yield an ester. A scheme consistent with isotope-labelling data may be represented as... 

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