Alkoxyphosphonium ions. 5. Kinetics of the Michaelis-Arbuzov intermediate

Article abstract of DOI:10.1139/v86-191

Rates of formation and destruction of the alkoxyphosphonium ion, the intermediate in the Michaelis-Arbuzov reactions of some methyl esters of trivalent phosphorus acids with methyl iodide, are followed by a conductivity method in the solvent propylene carbonate.Specific conductances of the unstable intermediates are well estimated through stable model salts.Rate constants for both the alkylation of the reagent and the dealkylation of the intermediate are obtained.The conductivity time curves are simulated by adjusting rate constants for two sequential second order reactions, assuming no ion pairing at the concentrations used.In these measurements of the intermediate only, there is no rate-determining step; for the overall rection the first step is in most cases rate-determining.