Nonaqueous phase liquids characteristics

Miller CT, Poirier-McNeil MM, Mayer AS (1990) Dissolution of trapped nonaqueous phase liquids mass transfer characteristics. Water Resour Res 26 2783-2796... 

Miller, C. X, M. M. Poirier-McNeill, and A. S. Mayer. 1990. Dissolution of Trapped Nonaqueous Phase Liquids Mass Transfer Characteristics, Water Resources Research, vol. 26, no. 11, pp. 2TS3-2796. 

Today, lipophilicity can be determined in many systems that are classified by the characteristics of the nonaqueous phase. When the second phase is an organic solvent (e.g. n-octanol), the system is isotropic, when the second phase is a suspension (e.g. liposomes), it is anisotropic, and when the second phase is a stationary phase in liquid chromatography, it is an anisotropic chromatographic system [6]. Here, we discuss the main aspects of isotropic and anisotropic lipophilicity and their biological relevance the chromatographic approaches are investigated in the following chapter by Martel et al. 

The EPR spectra of various Tc complexes have been investigated in detail. The EPR of the six-coordinate, deep blue complex [AsPh4]2[Tc(NO)(NCS)5], prepared from [NH4][Tc04] in dmf and in the presence of KNCS and H2N0H HC1, has been studied in nonaqueous solution in the liquid and in frozen glass phases. With gx = (+)2.045 and gn = (-I-) 1.928, and A = 0.0236 and x = 0-0095 cm , the spectrum is characteristic of a low-spin 4quadrupole moment observed is solvent dependent. " When Hacac is... 

In this chapter, the solubility of surfactant compounds in liquid water (and in selected nonaqueous solvents) will be considered. Surfactants are defined here as amphiphilic molecules (molecules containing both polar and nonpolar structural fragments) whose aqueous phase behavior displays explicitly stated features [3]. The most characteristic feature of surfactants is their ability to interact with water to form lyotropic liquid-crystal phases, but surf tant behavior is also jeflected by the influence of water on the temperature of the crystal solubility boundary relative to the melting point, and by the distinctive shape of liquid-liquid miscibility gaps (when they exist). Solubility is but one aspect of the broader subject of phase behavior—albeit a very important aspect. The aqueous phase behavior of surfactants has recently been treated in considerable detail [3]. 

First, it is clear that much of the complexity in surfactant phase behavior related to the existence of liquid-crystal phases, which are dominant features in water, does not exist in nonaqueous solvents [96]. The fundamental requirement for liquid-crystal formation is that one of the molecular fragments in amphiphilic molecules be highly incompatible with the solvent, and the other be highly compatible. If this severe exclusion of one part or the other is compromised in any way, the existence of liquid-crystal states (and the other characteristic features of aqueous surfactant phase behavior) is jeopardized and they may vanish altogether. This is apparent from data which show that introducing even weakly dipolar functional groups into lipophilic chains may destroy the surfactant-like aqueous phase behavior of the parent surfactant [97]. 

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