The kinetics of silver salts in an alcohol-silver salts-bromine reaction

摘要

The reaction of an alcohol with bromine and different silver salts yields a tetrahydrofuran derivative or a ketone. The kinetics of the reaction have been studied by ultraviolet spectrophotometry.;In this project, the effect of different silver halogenated acetates on the bromine-alcohol reaction have been examined. Specifically: The silver salt synthesis has been studied, the chemical features of the synthesized silver salts have been reported and their relative activity has been investigated. The quantitative techniques have been developed to determine the rate of formation of acetyl hypobromite and the formation of alkyl hypobromite. A group of reactions of bromine-silver halogenated acetates-alcohol has been tested and the kinetic data have been obtained. The kinetic data have been analyzed in terms of the postulated reaction mechanism of the alcohol-silver salts-bromine reaction.;The kinetics of the formation reaction of halogenated acetyl hypobromite and the kinetics of the formation reaction of tert-butyl hypobromite have been studied. The first order rate constants of formation of halogenated acetyl hypobromite have been obtained, the formation constant of acetyl hypobromite is 1.8 $pm$ 0.1 $times$ 10$sp{-4}$ (s$sp{-1}$), the formation constant of chloroacetyl hypobromite is 1.2 $pm$ 0.1 $times$ 10$sp{-4}$ (s$sp{-1}$), the formation constant of dichloroacetyl hypobromite is 6.7 $pm$ 0.1 $times$ 10$sp{-5}$ (s$sp{-1}$), the formation constant of trichloroacetyl hypobromite is 4.8 $pm$ 0.1 $times$ 10$sp{-5}$ (s$sp{-1}$), the formation constant of trifluoroacetyl hypobromite is 2.9 $pm$ 0.1 $times$ 10$sp{-5}$ (s$sp{-1}$).;The rate constants of formation of tert-butyl hypobromite have been studied, the formation constant of tert-butyl hypobromite is 1.0 $pm$ 0.1 $times$ 10$sp{-5}$ (s$sp{-1}$) in the reaction of tert-butyl alcohol with acetyl hypobromite, the formation constant of tert-butyl hypobromite is 8.3 $pm$ 0.1 $times$ 10$sp{-6}$ (s$sp{-1}$) in the reaction of tert-butyl alcohol with chloroacetyl hypobromite, the formation constant of tert-butyl hypobromite is 6.4 $pm$ 0.1 $times$ 10$sp{-6}$ (s$sp{-1}$) in the reaction of tert-butyl alcohol with dichloroacetyl hypobromite, the formation constant of tert-butyl hypobromite is 4.9 $pm$ 0.1 $times$ 10$sp{-6}$ (s$sp{-1}$) in the reaction of tert-butyl alcohol with trichloroacetyl hypobromite, the formation constant of tert-butyl hypobromite is 3.2 $pm$ 0.1 $times$ 10$sp{-6}$ (s$sp{-1}$) in the reaction of tert-butyl alcohol with trifluoroacetyl hypobromite.;The half-life of halogenated acetyl hypobromite and tert-butyl hypobromite have been tested at different temperatures. The half-life of acetyl hypobromite was 3.0 $pm$ 0.1 hours at 25$spcirc$C, the half life of chloroacetyl hypobromite was 1.6 $pm$ 0.1 hours at 25$spcirc$C, the half-life of dichloroacetyl hypobromite was 1.1 $pm$ 0.1 hours at 25$spcirc$C, and the half life of trichloroacetyl hypobromite was 0.24 $pm$ 0.01 hour at 25$spcirc$C, the half-life of trifluoroacetyl hypobromite was 0.13 $pm$ 0.01 hour at 25$spcirc$C.;The temperature effect of silver halogenated acetates on the bromine-alcohol reaction has been examined at 0$spcirc$C, 25$spcirc$C, 35$spcirc$C, and 45$spcirc$C.