Quantitative study of solvent effects on the Menshutkin reaction between 1,4-diazabicyclo[2.2.2]octane and 2-chloroethylbenzene, 2-bromoethylbenzene, and 2-iodoethylbenzene. Part 2. Mixed solvents

Abstract

We have elucidated by kinetic studies the complex behaviour of the protic compounds at low concentration in various solvents for the Menshutkin quaternation reaction between 1,4-diazabicyclo[2.2.2]octane and 2-chloroethyl-, 2-bromoethyl-, and 2-iodoethyl-benzene. The variation of the reaction rate is interpreted on the basis of non-specific physical and specific chemical effects. The specific effects arise from the formation of hydrogen bonded complexes between the protic compound and the amine, the halide, and the basic solvent. The deactivation of the amine and the activation of the halide in the presence of added protic compound have been found to be a function of the basicity of the main solvent.