자동적정법에 의한 Alkyl Halogenoformate Esters의 가용매 분해반응에 대한 속도론적 연구

Abstract

The specific rates of the solvolyses of methyl fluoroformate (CH3OCOF) and ethyl fluoroformate (CH3CH2OCOF) in pure and several hydroxylic solvents have been measured at 40.0°C and 24.2°C using the titrimetric method. The extended Grunwald-Winstein equation has been applied to the solvolyses of methyl fluoroformate and ethyl fluoroformate. Analyses of the data using the extended Grunwald-Winstein equation to the specific rates of the solvolyses of methyl fluoroformate and ethyl fluoroformate lead to sensitivities toward changes in solvent nucleophilicity (l) of 1.33±0.09 and toward changes in solvent ionizing power (m) of 0.73±0.06, and to sensitivities toward changes in solvent nucleophilicity (l) of 1.34±0.14 and toward changes in solvent ionizing power of (m) 0.77±0.07, respectively. For four and five representative solvents, studies were made at several temperatures and activation parameters determined. For methanolysis, a solvent deuterium isotope effect of MeOH/MeOD is compatible with the incorporation of general-base catalysis into the substitution process. In conclusion, the solvolyses of methyl fluoroformate and ethyl fluoroformate are indicated to proceed by a bimolecular addition-elimination pathway in pure and several hydroxylic solvents considered. These observations are also compared with those previously reported for the corresponding chloroformate and fluoroformate esters.