Empirical correlation between hydrophobic free energy and aqueous cavity surface area
The unitary free energy of transfer of a hydrocarbon molecule from a hydrocarbon solvent to an aqueous medium is a measure of the hydrophobic interaction in the aqueous medium. We have reexamined available data on this phenomenon and have confirmed that the free energy for saturated hydrocarbons is proportional to the surface area of the cavity created by the solute in the aqueous solution, with the same proportionality constant for linear, branched, and cyclic hydrocarbon molecules. The numerical value of the proportionality constant is uncertain because absolute and self-consistent area measurements are not available. We estimate that it falls between 20 and 25 cal/mole per Angstrom/sup 2/ at 25/sup 0/ (for areas measured at the distance of closest approach of water molecules), which is significantly less than the figure of 33 cal/mole per Angstrom/sup 2/ that has been assigned to the same parameter by Hermann.
- Research Organization:
- Duke Univ Med Center
- OSTI ID:
- 6645423
- Journal Information:
- Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 71:8
- Country of Publication:
- United States
- Language:
- English
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