The kinetic behavior of alkaline hydrolysis of 2-alkyl-2-oxo-1,3-dioxaphosphorinane and phosphepane in various solvents was investigated. In 50% aqueous DMSO, alkaline hydrolysis of these two cyclic esters of alkylphosphonates behaves as a second order reaction. Multiple regression analyses involving log k with s* and DDE gave very good results. It showed that the alkyl substituents effect on the rate of hydrolysis of these two alkylphosphonates is very similar. Log k for alkaline hydrolysis in various solvents do not relate either with the dielec. constant or with the solvent parameter ET. However, the strength of proton-donor and acceptor solvents showed significant influence on the alkaline hydrolysis of the title compounds

Key words: SOLVENTS, SULFOXIDE, REACTION KINETICS, HYDROLYSIS, ORGANO PHOSPHORUS COMPOUNDS, PHOSPHONIC ACID ESTER, REACTION RATE CONSTANT, SUBSTITUENT GROUP, ALKYL