Use of Empirical Correlations to Determine Solvent Effects in the Solvolysis of S-Methyl Chlorothioformate

International Journal of Molecular Sciences

Malcolm J. D’Souza¹  Stefan M. Hailey¹ 

[1] Department of Chemistry, Wesley College, 120 N. State Street, Dover, Delaware 19901-3875, USA

关键词: solvolysis;    nucleophilicity;    ionizing power;    S-methyl chlorothioformate;    chloroformates;    thioesters;    thiochloroformate;    Grunwald-Winstein Equation;    Linear Free Energy Relationships;   

DOI  :  10.3390/ijms11052253

来源: mdpi

【 摘 要 】

The specific rates of solvolysis of S-methyl chlorothioformate (MeSCOCl) are analyzed in 20 solvents of widely varying nucleophilicity and ionizing power at 25.0 °C using the extended Grunwald-Winstein Equation. A stepwise S_N1 (D_N + A_N) mechanism is proposed in the more ionizing solvents including six aqueous fluoroalcohols. In these solvents, a large sensitivity value of 0.79 towards changes in solvent nucleophilicity (l) is indicative of profound rearside nucleophilic solvation of the developing carbocation. In twelve of the more nucleophilic pure alchohols and aqueous solutions, the sensitivities obtained for solvent nucleophilicity (l) and solvent ionizing power (m) are similar to those found in acyl chlorides where an association-dissociation (A_N + D_N) mechanism is believed to be operative.

【 授权许可】

CC BY   
© 2010 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland.