The reactions of bromotrichloromethane and bromine with halogenated methanes

Abstract

Over the past few years, the abstraction and addition reactions of trichloromethyl radicals, produced by the photolysis of bromotrichloromethane have been studied in this laboratory. The addition reactions of the trichloromethyl radical have thrown considerable light onto the factors influencing the direction of addition to substituted olefins. The hydrofen abstraction reactions from substituted alkanes have indicated that the trichloromethyl radical is comparable in selectivity to the bromine atom.

The purpose of this work was to obtain absolute Arrhenius parameters for the abstraction of hydrogen from a representative selection of polychlorofluoromethanes. The results obtained are compared with the results obtained for similar reactions with methyl tadicals and trifluoromethyl radicals. In order to reduce the unknown rate constants in the computer analysis of the proposed reaction mechanism, the brominations of all the halomethanes, for which literature data did not exist, were carried out. The thesis is divided into two parts: - Part I deals with the reaction of trichloromethyl radicals with difluoromethane (section I); chlorofluoromethane (section II), dichloromethane (section III) and dichlorofluoromethane (section IV) and Part II deals with the competitive brominations of chlorofluoromethane, dichloromethane and dichlorofluoromethane.