Hydrogen bonding between solutes in solvents octan-1-ol and water.
The 1:1 equilibrium constants, K, for the association of hydrogen bond bases and hydrogen bond acids have been determined by using octan-1-ol solvent at 298 K for 30 acid-base combinations. The values of K are much smaller than those found for aprotic, rather nonpolar solvents. It is shown that the log K values can satisfactorily be correlated against α(H)2·β(H)2, where α(H)2 and β(H)2 are the 1:1 hydrogen bond acidities and basicities of solutes. The slope of the plot, 2.938, is much smaller than those for log K values in the nonpolar organic solvents previously studied. An analysis of literature data on 1:1 hydrogen bonding in water yields a negative slope for a plot of log K against α(H)2·β(H)2, thus showing how the use of very strong hydrogen bond acids and bases does not lead to larger values of log K for 1:1 hydrogen bonding in water. It is suggested that for simple 1:1 association between monofunctional solutes in water, log K cannot be larger than about -0.1 log units. Descriptors have been obtained for the complex between 2,2,2-trifluoroethanol and propanone, and used to analyze solvent effects on the two reactants, the complex, and the complexation constant.
Abraham
Michael H
MH
Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, United Kingdom.
Gola
Joelle M R
JM
Cometto-Muñiz
J Enrique
JE
Acree
William E
WE
D006860:Hydrogen Bonding; D000442:Octanols / Q000737:chemistry*; D012995:Solubility; D012997:Solvents / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
D000442:Octanols; D012997:Solvents; D014867:Water