R. B. Gutsulyak

Active intermediates in the oxidative bromochlorination of olefins in concentrated hydrochloric acid

A study was carried out on the oxidative bromochlorination of olefins in the presence of KBr using hydrogen peroxide and an electrochemical technique. Asymmetric trihalide anions, Br2Cl− and BrCl2−, were found to be the active bromochlorination reagents. The reaction mechanism was discussed.

Ab initio quantum chemical calculation of the mechanism for molecular addition of chlorine to acetylene in the gas phase

We have investigated the mechanism of gas-phase chlorination of acetylene using anab initio quantum chemical method in a 3–21G° basis. We show that formation ofcis andtrans addition products may be connected with the appearance of carbene in the reaction medium, formed upon addition of a chlorine molecule to one of the acetylene carbon atoms. We have found that intermediate carbene may also be a source for the appearance of radicals in the reaction medium.

Stereoselective chlorination of phenylacetylene compounds in the systems K2S2O8-MCln-pyridine

It was shown that the main products of oxidative chlorination of acetylenes by the system K2S2O8-MCln in pyridine are transdichloroalkenes. It was established that the formation of chloro-derivatives from unsaturated hydrocarbons proceeds only in the presence of ions of metals of variable valence (Cu2+, Co2+, Fe3+). A possible reaction scheme is proposed.

Complex formation effects during the oxidation of cyclohexene with lead tetraacetate

The effect of complex formation between lead(IV) and trifluoroacetic or methanesulfonic acid and chloride ion in acetic acid and Freon 113 on the oxidation of cyclohexene by lead tetraacetate was investigated. As a result of the reaction the β-chlorocyclohexyl esters of the corresponding acids are formed with high yields. The formation of the complexes Pb(OAc)4−nLn and Pb(OAc)4−(n+1)LnCl, where L = CF3CO2- or CH3SO3- with n=1 or 2, was demonstrated by potentiometric titration. A scheme is proposed for the oxidation of cyclohexene with the participation of unlike-ligand complexes of Pb(IV).