Hydrophilic effects

SlogP VSA(. (10) intended to capture hydrophobic and hydrophilic effects ... 

Leo et al. indicated that the van der Waals volume is linearly related to hydro-phobicity for non-polar compounds expressed in terms of log P (octanol/water)66). Moriguchi et al. showed that the log P value is generally factored into two components attributable to hydrophilic effect of polar group and hydrophobic effect due to the net molar volume 67). Thus, the van der Waals volume could be a parameter related to solute-solvent interactions and partition coefficient. 

The stability of the complex is proportional to the hydrophobic character of the substituents thus, a methyl or ethyl substituent will increase the stability. Hydroxyl groups hinder complex formation, and their hydrophilic effects decrease in the OKstthio> meta> para. In the case of amine groups, it is important whether they are present in their neutral form or ionized form. Ionic species usually do not form stable complexes (Szejtli, 1982). 

LBKE can be further modified to capture the multicomponent/multiphase phenomena in GDL as well as GC. This modification also allows modeling the hydrophilic effect such as the bubble transport phenomenon. Lu and Wang visualized the bubble phenomenon in situ using the... 

The solubility of noble gases in various solutions (often aqueous-nonaqueous mixtures) gives indications of both hydrophobic and hydrophilic effects (Fig. 2.68). When substances exhibiting both effects are present, there is a maximum in the solubility of argon. Thus (Fig. 2.68, curve 1) in the system water-acetone, no hydrophilic effects are caused by the added solvent component, and the solubility increases. On the other hand, for systems in which urea is added, there are no hydrophobic effects and the solubility or the gas therefore deaeases. In curve 2 of Fig. 2.68, hydrophilic and hydrophobic effects compete (due to the properties of acetamide in water) and there is a maximum on the curve. 

Model for predicting lipophilicity of compounds based on the -> solvent-accessible surface area SASA generated by a solvent probe of radius 1.4 A and a set of parameters encoding hydrophilic effects of polar groups [Iwaseef al., 1985] ... 

In this chapter, approaches to estimates of (1) the polyelectrolyte (electrostatic) effect, (2) the hydrophobicity/hydrophilicity effect, and (3) the multicoordination effect, specified for metal ion/polyelectrolyte systems are described. As weak acidic polyelectrolytes, polyacrylic acid, PAA, as well as polymethacrylic acid, PMA, are exemplified as an example of weak basic polyelectrolyte, poI y(/V-vinyI i m idazoIc), PVIm, is chosen all the chemical structures of the polymer ligands are illustrated in Figure 1. Precise poten-tiometric titration studies by the use of a glass electrode as well as respective metal ion selective electrodes have been performed for the complexation equilibrium analyses. All the equilibrium constants reported in this chapter were obtained at 298 K unless otherwise stated. 

A hydrophilic molecule or a hydrophilic group of a molecule is generally polar and capable of H-bonding, enabling it to dissolve more readily in water than in oil or other hydrophobic solvents. It has a strong affinity with water tending to dissolve in, mix with, or be wetted by water. When two solute molecules repel each other in water it is called hydrophilic interaction. However there is no phenomenon known as the hydrophilic effect. 

Here the surface atoms can form strong HBs with water molecules and exert influence on the extended HB network of water. Another important class of systems is aqueous binary mixtures, where both hydrophobic and hydrophilic interactions together determine many of the unusual properties exhibited by these systems. The hydrophilic effect is partly responsible for water being such a good solvent for a large number of polar molecules. Hydrophilic interaction also finds great use in industry, as in hydrophilic chromatography. 

Despite their importanee, a satisfaetory microscopic understanding of such exotic properties is not available even now beeause of the complexity in the nature of their interactions. We have seen in the last two ehapters that description of either hydro-phobic or hydrophilic effects itself is quite difficult. Not surprisingly therefore the development of a theory of amphiphUie binaiy mixtures has been left for posterity. 

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