Correlation of the Rates of Solvolysis of i-Butyl Fluoroformate and a Consideration of Leaving-Group Effects

International Journal of Molecular Sciences

Yelin Lee¹  Kyoung-Ho Park¹  Mi Hye Seong¹  Jin Burm Kyong¹ 

[1] Department of Chemistry and Applied Chemistry, Hanyang University, Ansan-si, Gyeonggi-do 426-791, Korea; E-Mails:

关键词: i-butyl fluoroformate;    Grunwald-Winstein equation;    leaving group effect;    addition-elimination;    solvolysis;   

DOI  :  10.3390/ijms12117806

来源: mdpi

【 摘 要 】

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.

【 授权许可】

CC BY   
© 2011 by the authors; licensee MDPI, Basel, Switzerland.