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Effect of solvent composition on the acidity of phenols in dimethyl sulfoxide–water mixtures
Author(s) -
Tarkka Richard M.,
Um IkHwan,
Xie HaiQi,
Chatrouse AlanPierre,
Terrier Francois,
Hoz Shmaryahu,
Buncel Erwin
Publication year - 1998
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/(sici)1099-1395(199812)11:12<847::aid-poc42>3.0.co;2-5
Subject(s) - chemistry , dimethyl sulfoxide , solvent , phenols , composition (language) , linear relationship , sulfoxide , organic chemistry , thermodynamics , inorganic chemistry , philosophy , linguistics , statistics , mathematics , physics
The effect of solvent composition on the acidity of substituted phenols in DMSO–H 2 O systems was examined. It is shown that in DMSO–H 2 O mixtures with up to 35 mol% DMSO there is a linear relationship between the p K a values of monosubstituted phenols in the binary solvent mixtures of different compositions and the corresponding p K a values in water. This leads to an equation relating the slope and intercept terms, p K a (DMSO–H 2 O) = slope[p K a (H 2 O)] + intercept. The basis of this relationship in the Kirkwood–Westheimer equation is examined. The significance of a possible ‘supersolvent’ is discussed. The applicability of the relationships derived herein to other rate–equilibria relationships and solvent mixtures is considered. Copyright © 1998 John Wiley & Sons, Ltd.