Aqueous solution data octanol-water partition constant

Many additional consistency tests can be derived from phase equiUbrium constraints. From thermodynamics, the activity coefficient is known to be the fundamental basis of many properties and parameters of engineering interest. Therefore, data for such quantities as Henry s constant, octanol—water partition coefficient, aqueous solubiUty, and solubiUty of water in chemicals are related to solution activity coefficients and other properties through fundamental equiUbrium relationships (10,23,24). Accurate, consistent data should be expected to satisfy these and other thermodynamic requirements. Furthermore, equiUbrium models may permit a missing property value to be calculated from those values that are known (2). 

A more complex kind of partition is that of the distribution of small organic molecules between proteins and an aqueous phase. A number of such studies 41) have been correlated by an equation similar to Eq. (16) with the octanol-water partition coefficient and K2 the binding constant of the solute with protein or the ratio of the percent bound solute to the percent free solute. In other studies (47), the binding constant is expressed as 1/C, where C is the molar concentration of the solute necessary to produce a 1 1 (or higher) complex of protein and the solute molecule. The way that K2 is defined greatly affects the intercept and makes it difficult to compare with the data of ordinary solvent-... 

Computerized method provides convenient and accurate determination of the ionization constant in aqueous solution and of the apparent ionization constant in the presence of octanol. From these parameters, partition coefficients and apparent partition coefficients are easily calculated and agree with data reported using the shaker technique or HPLC. The curve-fitting method has been applied to the differential titration technique in which the solvent curve is subtracted from the solution curve before calculations are begun. This method has been applied to the potentiometric titration of aqueous solutions of the salts of bases with very low solubility in water. 

---