Monomeric solubility

The triaLkoxy(aryloxy)boranes are typically monomeric, soluble in most organic solvents, and dissolve in water with hydrolysis to form boric acid and the corresponding alcohol and phenol. Although the rate of hydrolysis is usually very fast, it is dependent on the bulk of the alkyl or aryl substituent groups bonded to the boron atom. Secondary and tertiary alkyl esters are generally more stable than the primary alkyl esters. The boron atom in these compounds is in a trigonal coplanar state with bond hybridization. A vacantp orbital exists along the threefold axis perpendicular to the BO plane. 

Monomeric, soluble Mo(III) precursors are extremely useful chemical intermediates, their uses ranging from transformation to other Mo(III) coordination compounds,1 reduction to dinitrogen complexes,2 conversion to metal-metal bonded compounds,3 and formation of new materials.4... 

The arenethiolates [M(SR)3] (R = phenyl or naphthyl) were easily obtained as monomeric soluble products by reductive elimination of organic disulfides from the pentathiolates... 

Fig. 4.19 is a cross-section the actual micelle structure is three-dimensional. The assembled structure is completely nonregular rapid exchange between micelle molecules and monomeric soluble molecules occurs. Therefore, a micelle can be regarded as a disordered dynamic supramolecular assembly. In a micellar structure, the hydrophilic part of the component molecule is located on the outer surface of the micelle, in contact with the aqueous phase, which minimizes the unfavorable contact of the hydrophobic part with water. Micelles can trap organic materials hke oils in the inner hydrophobic core, so micelle formation is used in many cleaning agents. 

Ushiyama, S, Laue, T M, Moore, K L, Erickson, H P, McEver, R P, Structural and functional characterization of monomeric soluble P-selectin and comparison with membrane P-selectin, J. Biol. Chem., 268, 15229-15237, 1993. 

In one-phase micro emulsions the surfactant molecules partition between the microscopic water/oil interface and the microemulsion sub-phases (e.g. in swollen micelles or bicontin-uous oil- and water-rich domains) in which they are dissolved monomerically. They also dissolve monomerically in coexisting excess phases and adsorb at the macroscopic interfaces between the phases. The significance of this fact is that these parts of the surfactant are not available for the micro-emulsification of water and oil. Thus, for technical applications surfactants with high amphiphilicity but small monomeric solubilities in both solvents are desirable. 

The monomeric solubility of the surfactant in the water y cmon.a can be easily determined from surface tension measurements [37]. An interesting method to obtain ycmon.b is provided by the macroscopic phase behaviour through the determination of the mass fraction of surfactant y0 (see Fig. 1.3), i.e. the monomerically dissolved surfactant in both excess phases. Therefore, the volume fraction of the middle phase Vc/V has to be measured as a function of the mass fraction of surfactant y at a constant = 0.5 and the mean temperature f of the three-phase body [34, 38, 39]. Plotting Vc/V versus y yields yoat Vc/V = 0andy at Vc/V = 1.Then the monomeric solubility in the oil is calculated from... 

Figure 1.6 Monomeric solubility 7Cm011 b of 14 different surfactants in n-octane at the mean temperature f obtained from the determination of y0 (see Fig. 1.3) [34]. Note the similar patterns of the f CYcmon.b) plot and the f(y) plot (see Fig. 1.5), respectively. (From Ref. [34], reprinted with permission of the Royal Society of Chemistry.)...

Figure 1.13 Schematic representation of the water/oil interfacial tension = 0.50, the interfacial tension (Xat, decreases from 50 mN m 1 to values as low as 1 0-4 mN m 1. After having crossed the monomeric solubility 70 of the surfactant in the water- and oil-rich phase, 70, where the microemulsion phase (c) exist in form of a lens (right). (From Ref. [26], reprinted with permission of Elsevier.)...

Burauer, S., Sachert, T., Sottmann, T. and Strey, R. (1999) On microemulsion phase behavior and the monomeric solubility of surfactant. Phys. Chem. Chem. Phys., 1, 4299-4306. 

Yamaguchi, S. and Kunieda, H. (1997) Determination of a three-phase tie triangle (the hydrophile-lipophile balance plane) in a composition tetrahedron Evaluation of the composition of adsorbed mixed-surfactant and the monomeric solubilities of short-chain surfactant. Langmuir, 13, 6995-7002. 

The self-assembly of amphiphilic molecules in non-aqueous polar solvents is usually attenuated compared to that in water. The CMCs increase significantly upon the substitution of water by polar solvents [2, 57, 58]. For example, the CMC of ionic surfactants in ethylene glycol are two orders of magnitude larger than that in water [57], while the monomeric solubility of sodium dodecyl sulphate in formamide is so high that micelles do not form at all [58]. Attenuation of self-assembly in non-aqueous polar solvents is the result of the reduced free energy of repulsion between polar solvents and the solvent-phobic parts of amphiphiles compared to that in water. 

In order to determine the monomeric solubility of the non-ionic Ci0E4 in triolein, the volume fractions of the middle phase VJV were measured as function of the overall surfactant mass fraction y in the three-phase region of the system H2O/NaCl-triolein-Ci0E4 at T = 61.80°C. 

Monomeric soluble transition metal phthalocyanines MPCR4 (R = tcrt-butyl or... 

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