Menschutkin reaction of triethylamine and of pyridine with methyl iodide. Activation enthalpy versus activation entropy correlations and extended Brönsted treatments in acetonitrile–methanol mixtures

Abstract

The rate constants and activation parameters for the reaction of triethylamine with methyl iodide and for pyridine with methyl iodide have been determined in acetonitrile–methanol mixtures. Enthalpies of solution have also been determined for triethylamine, pyridine, triethylmethylammonium iodide, and methylpyridinium iodide in the same solvent mixtures. Transfer enthalpies of amines and of quaternary ammonium iodide have been split into constituent terms, i.e., ‘more physical’ interaction and specific interaction enthalpies. Correlations involving activation enthalpy versus activation entropy plots, and extended Brönsted plots, yielded straight lines only when corrected for the specific interaction term.