title: Correlation of the rates of solvolysis of i-butyl fluoroformate and a consideration of leaving-group effects.
abstract: The specific rates of solvolysis of isobutyl fluoroformate (1) have been measured at 40.0 °C in 22 pure and binary solvents. These results correlated well with the extended Grunwald-Winstein (G-W) equation, which incorporated the N(T) solvent nucleophilicity scale and the Y(Cl) solvent ionizing power scale. The sensitivities (l and m-values) to changes in solvent nucleophilicity and solvent ionizing power, and the k(F)/k(Cl) values are very similar to those observed previously for solvolyses of n-octyl fluoroformate, consistent with the additional step of an addition-elimination pathway being rate-determining. The solvent deuterium isotope effect value (k(MeOH)/k(MeOD)) for methanolysis of 1 was determined, and for solvolyses in ethanol, methanol, 80% ethanol, and 70% TFE, the values of the enthalpy and the entropy of activation for the solvolysis of 1 were also determined. The results are compared with those reported earlier for isobutyl chloroformate (2) and other alkyl haloformate esters and mechanistic conclusions are drawn.
authors.affiliation: Department of Chemistry and Applied Chemistry, Hanyang University, Ansan-si, Gyeonggi-do 426-791, Korea; E-Mails:  redstar486@hanyang.ac.kr  (Y.L.);  piroho@hanyang.ac.kr  (K.-H.P.);  tpdlqk85@hanmail.net  (M.H.S.).
authors.forename: Yelin
authors.initials: Y
authors.lastname: Lee
authors.forename: Kyoung-Ho
authors.initials: KH
authors.lastname: Park
authors.forename: Mi Hye
authors.initials: MH
authors.lastname: Seong
authors.forename: Jin Burm
authors.initials: JB
authors.lastname: Kyong
authors.forename: Dennis N
authors.initials: DN
authors.lastname: Kevill
mesh_terms: D000431:Ethanol / Q000737:chemistry; D005561:Formates / Q000737:chemistry*; D005650:Fumarates / Q000737:chemistry*; D000432:Methanol / Q000737:chemistry; D015394:Molecular Structure; D012997:Solvents / Q000737:chemistry*
chemical_list: D005561:Formates; D005650:Fumarates; D012997:Solvents; D000431:Ethanol; C039311:isobutyl chloroformate; D000432:Methanol