Grunwald-Winstein analysis: isopropyl chloroformate solvolysis revisited.
Specific rates of solvolysis at 25 degrees 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 degrees 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 CO(2) 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.
D'Souza
Malcolm J
MJ
Department of Chemistry, Wesley College, 120 N. State Street, Dover, Delaware 19901-3875, USA.
Reed
Darneisha N
DN
Department of Chemistry, Wesley College, 120 N. State Street, Dover, Delaware 19901-3875, USA.
Erdman
Kevin J
KJ
Department of Chemistry, Wesley College, 120 N. State Street, Dover, Delaware 19901-3875, USA.
Kyong
Jin Burm
JB
Department of Chemistry and Applied Chemistry, Hanyang University, Ansan, Kyunggi-do, 425-791, Korea.
Kevill
Dennis N
DN
Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115-2862, USA.
D005561:Formates / Q000737:chemistry*; D007700:Kinetics; D012997:Solvents / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000737:chemistry
D005561:Formates; D012997:Solvents; D014867:Water; C030544:formic acid