AbstractThe alcoholyses of ethyl fluorosulphate in methyl, ethyl,n‐propyl, isopropyl,n‐butyl, isobutyl,tert‐butyl andn‐pentyl alcohols in the initial concentrations and temperature ranges of (1–10) 10−3M and − 15.00 to 22.00 °C, respectively, were studied. The reactions follow pseudo‐first‐order kinetic laws up to at leastca75 per cent ester conversions. At 10°C the experimental rate constant for ethanolysis is similar to that of ethyl triflate but much smaller than for its hydrolysis. The reactivity of the ester isca104–105times higher than that of alkyl halides and benzenesulphonates. In alcohol–benzene and alcohol–acetone mixtures the ΔH≠and ΔS≠activation parameters are only slightly affected by the media composition. The effect of the ‘lyate ion’ on the kinetics of these reactions were investigated and the effects of changes in the dielectric constant of the media were evaluated. It is concluded that the alcoholyses of the ester fulfil the requirements for predominantSN2‐type mechanism, where the reaction ground states are more polar tha