Rate and Product Studies with Methanesulfonic Anhydride Under Solvolytic Conditions and a Comparison with Methanesulfonyl Chloride Solvolysis

Dennis N. Kevill 1Zoon Ha Ryu 2Malcolm J. D Souza 3Lamia Yaakoubd 3Fumie Koyoshi 3

1. Northern Illinois University, Dekalb, Illinois 60115-2862, United States
2. Dong-Eui University, 995 Eomgwangno, Busan-Jin-Gu, Busan 614-714, Korea, South
3. Wesley College, 120 N. State Street, Dover, DE 19901, United States

Abstract

The specific rates of solvolysis of methanesulfonic anhydride have been measured conductometrically at -10 °C in 41 solvents. Use of the extended Grunwald-Winstein equation (with the NT scale of solvent nucleophilicity and YOTs scale of solvent ionizing power) leads to an l value of 0.95 and an m value of 0.61 with a multiple correlation coefficient (R) of 0.973. Selectivity values in binary hydroxylic solvents favor alcohol attack in EtOH-H2O (S value of 1.2 in 90% EtOH rising to 4.0 in 40% EtOH) and in MeOH-H2O (S value of 3.7 in 90% MeOH rising to 6.0 in 50% MeOH). In 2,2,2-trifluoroethanol-H2O, S values are much lower (at about 0.1). Entropy of activation values are appreciably negative (-12 to -34 cal mol-1 K-1).
Literature values (I. S. Koo, K. Yang, S. K. An, S.-K. Lee, I. Lee, Bull. Korean Chem. Soc. 2000, 21, 1011) for the specific rates of solvolysis of methanesulfonyl chloride have been extended to fluoroalcohol-containing solvents and for 42 solvents at 45.0 °C values are obtained (using NT and YCl values) of 1.29 for l and of 0.55 for m (R = 0.964).
It is proposed that both substrates solvolyze by an SN2 pathway.

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Presentation: oral at 18th Conference on Physical Organic Chemistry, Symposium 2, by Dennis N. Kevill
See On-line Journal of 18th Conference on Physical Organic Chemistry

Submitted: 2006-05-09 18:48
Revised:   2009-06-07 00:44
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