Extended Grunwald-Winstein analysis - LFER used to gauge solvent effects in p-nitrophenyl chloroformate solvolysis.
Specific rates of solvolysis at 25 degrees C for p-nitrophenyl chloroformate (1) are analyzed using the extended (two-term) Grunwald-Winstein equation. For 39 solvents, the sensitivities (l = 1.68+/-0.06 and m = 0.46+/-0.04) towards changes in solvent nucleophilicity (l) and solvent ionizing power (m) obtained, are similar to those previously observed for phenyl chloroformate (2) and p-methoxyphenyl chloroformate (3). The observations incorporating new kinetic data in several fluoroalcohol-containing mixtures, are rationalized in terms of the reaction being sensitive to substituent effects and the mechanism of reaction involving the addition (association) step of an addition-elimination (association-dissociation) pathway being rate-determining. The l/m ratios obtained for 1, 2, and 3, are also compared to the previously published l/m ratios for benzyl chloroformate (4) and p-nitrobenzyl chloroformate (5).
D'Souza
Malcolm J
MJ
Department of Chemistry, Wesley College, 120 N. State Street, Dover, Delaware 19901-3875, USA.
Shuman
Kevin E
KE
Department of Chemistry, Wesley College, 120 N. State Street, Dover, Delaware 19901-3875, USA.
Carter
Shannon E
SE
Department of Chemistry, Wesley College, 120 N. State Street, Dover, Delaware 19901-3875, USA.
Kevill
Dennis N
DN
Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115- 2862, USA.