Grunwald-Winstein Analysis - Isopropyl Chloroformate Solvolysis Revisited

International Journal of Molecular Sciences

Malcolm J. D’Souza¹  Darneisha N. Reed¹  Kevin J. Erdman¹  Jin Burm Kyong² 

[1] Department of Chemistry, Wesley College, 120 N. State Street, Dover, Delaware 19901-3875, USA;Department of Chemistry and Applied Chemistry, Hanyang University, Ansan, Kyunggi-do, 425-791, Korea

关键词: Solvolysis;    solvolysis-decomposition;    nucleophilicity;    ionizing power;    isopropyl chloroformate;    chloroformates;    Grunwald-Winstein Equation;    Linear Free Energy Relationships;   

DOI  :  10.3390/ijms10030862

来源: mdpi

【 摘 要 】

Specific rates of solvolysis at 25 °C for isopropyl chloroformate (1) in 24 solvents of widely varying nucleophilicity and ionizing power, plus literature values for studies in water and formic acid, are reported. Previously published solvolytic rate constants at 40.0 °C are supplemented with two additional values in the highly ionizing fluoroalcohols. These rates are now are analyzed using the one and two-term Grunwald-Winstein Equations. In the more ionizing solvents including ten fluoroalcohols negligible sensitivities towards changes in solvent nucleophilicity (l) and very low sensitivities towards changes in solvent ionizing power (m) values are obtained, evocative to those previously observed for 1-adamantyl and 2-adamantyl chloroformates 2 and 3. These observations are rationalized in terms of a dominant solvolysis-decomposition with loss of the CO₂ molecule. In nine of the more nucleophilic pure alchohols and aqueous solutions an association-dissociation mechanism is believed to be operative. Deficiencies in the acid production indicate 2-33% isopropyl chloride formation, with the higher values in less nucleophilic solvents.

【 授权许可】

CC BY   
© 2009 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland. This article is an open-access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/).