The kinetics of reactions of chlorine, bromine, bromine monochloride, iodine monochloride, and iodine monobromide with phenyltrimethylsilane

Abstract

Halogens and interhalogens, XY, react with PhSiMe₃ in 98.5% aqueous acetic acid to give (Me₃Si)₂O, H⁺, Y^–, and PhX (X = Y = Cl, Br; X = Br, Y = Cl; X = I, Y = Br or Cl). Kinetic measurements at 30.0 °C show that all reactions are first order in PhSiMe₃, reactions with BrCl and Cl₂ are first order in halogen, reactions with ICl and IBr are second order in halogen, and reactions with Br₂ involve both first- and second-order terms. Rate coefficients for all the reactions are reported. The kinetics of the reactions of Br₂, ICl, and IBr are complicated by formation of trihalide complexes between the halogen and halide ion product. The formation constants for these complexes have been measured, and a numerical integration method is described to calculate the rate coefficients for these halogenations from the experimental data.