Holtzer A
Department of Chemistry, Washington University, St. Louis, Missouri 63130-4899.
Biopolymers. 1992 Jun;32(6):711-5. doi: 10.1002/bip.360320611.
Solute partitioning data for dilute solutions have almost invariably been interpreted by equating experimental values of -RT in Kx (wherein Kx is the mole fraction partition coefficient) to delta mu infinity, the standard Gibbs energy change for solute transfer from one solvent to another. Recently, it has been alleged that this relation is insufficiently general. Instead, the statistical mechanical Flory-Huggins (FH) theory has been recommended for use, because it is designed to account for disparities in molecular size between solute and solvent. Our examination of the thermodynamics of partitioning shows that: (1) The customary interpretation is not only entirely correct (providing only that the solute is dilute), but is model-independent. (2) The dilute limit of the FH theory is seen to agree entirely with the usual interpretation of -RT in Kx, once certain misnomers are cleared away. (3) The use of FH theory being urged upon us in fact serves only to extract from delta mu infinity (the latter quite correctly determined as -RT in Kx) the contact part of delta mu infinity in order to obtain information on hydrophobic interactions. Some caveats are cited concerning such use of the FH statistical mechanical model.
稀溶液的溶质分配数据几乎总是通过将-RTlnKx（其中Kx是摩尔分数分配系数）的实验值与Δμ∞（溶质从一种溶剂转移到另一种溶剂的标准吉布斯自由能变化）相等来解释。最近，有人声称这种关系不够普遍。相反，有人推荐使用统计力学的弗洛里-哈金斯（FH）理论，因为它旨在考虑溶质和溶剂之间分子大小的差异。我们对分配热力学的研究表明：（1）通常的解释不仅完全正确（前提是溶质是稀溶液），而且与模型无关。（2）一旦消除某些误称，FH理论的稀溶液极限被发现与-RTlnKx的通常解释完全一致。（3）敦促我们使用FH理论实际上只是为了从Δμ∞（后者正确地确定为-RTlnKx）中提取Δμ∞的接触部分，以便获得关于疏水相互作用的信息。文中列举了一些关于使用FH统计力学模型的注意事项。
