EMPIRICAL CORRELATION BETWEEN HYDROPHOBIC FREE-ENERGY AND AQUEOUS CAVITY SURFACE-AREA
EMPIRICAL CORRELATION BETWEEN HYDROPHOBIC FREE-ENERGY AND AQUEOUS CAVITY SURFACE-AREA
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DOI：
10.1073/pnas.71.8.2925
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发表时间：
1974-01-01
影响因子：
11.1
通讯作者：
TANFORD, C
中科院分区：
文献类型：
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作者：
REYNOLDS, JA;GILBERT, DB;TANFORD, C
烃分子从烃溶剂转移到水性介质的单位自由能是水性介质中疏水相互作用的量度。我们重新研究了关于这种现象的可用数据，并证实了饱和烃的自由能与水溶液中溶质所产生的空腔的表面积成比例，对于直链、支链和环状烃分子具有相同的比例常数。比例常数的数值是不确定的，因为没有绝对和自洽的面积测量。我们估计，在25°角时，它福尔斯在20 ~ 25卡/摩尔/立方厘米之间（在水分子最接近的距离处测量的面积），这比赫尔曼[J. Phys. Chem. 76，2754-2759（1972）]指定的33卡/摩尔/立方厘米的数字要小得多。一个小的差异存在类似的数据时，同源系列的烷基衍生物相比，基于烃本身的结果，并讨论了可能的原因。
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 Å2at 25° (for areas measured at the distance of closest approach of water molecules), which is significantly less than the figure of 33 cal/mole per Å2that has been assigned to the same parameter by Hermann [J. Phys. Chem.76, 2754-2759 (1972)]. A small discrepancy exists when similar data for homologous series of alkyl derivatives are compared with results based on hydrocarbons themselves, and possible reasons for it are discussed.