Mixed solvent water

B. Effect of Mixed Solvent-Water Systems on Grafting... 

The isotopic abundance of deuterium in the L30+ ion will differ from that in the water with which it is equilibrated. This is expressed in terms of the fractionation factor / which is the ratio of D/H ratios in the lyonium ion and the mixed solvent (water)... 

The calculations have been carried out for those systems for which the solubility calculations have been performed. The dilute region of sodium chloride (c < 0.3) was selected to ensure that the condition F /x = s = constant is satisfied. The partial molar volume was estimated using literature data [67-69]. According to the latter data, depends weakly on C3 and this dependence is linear in the dilute range [68,69]. For sodium chloride and potassium chloride, decreases by at most 1 cm /mol when Cj is changed from 0 to 2mol/l. In our calculations, the above decrease was taken 1 cm /mol. On this basis the composition dependence of was evaluated in the composition range 0 < C3 < 0.3. The partial molar volumes Vi and V3 of water and sodium chloride in the binary mixture water (1) + sodium chloride (3) were obtained from data available in the literature [70,71], and the composition dependence of the isothermal compressibility of the mixed solvent (water (1) + sodium chloride (3)) was taken from reference [71]. 

Fig. 1. Comparison between experimental (O) (Jouyban et al., 2002) and predicted (solid lines) solubilities of oxolinic acid (S is the mole fraction of oxolinic acid) in the mixed solvent water/ethanol (xet is the mole fraction of ethanol) at room temperature. 1—solubility calculated using Eqs. (23) and (25), 2—solubility calculated using Eqs. (23) and (18), and 3— the solubility calculated using Eq. (4).

Quinary Mixed Solvent. The solubilities of naphthalene and anthracene in quinary mixed solvents (water/methanol/ ethanol/2-propanol/acetone) were predicted using Equation 23. The molar volume of an ideal quinary mixed solvent was calculated as... 

Equations 3 and 5 allow one to calculate the Kirkwood-Buff integrals G12 and G23 using experimental data regarding the preferential binding parameters r2 and the partial molar volume of a protein at infinite dilution in a mixed solvent 49-50,52 jjjg Kirkwood—Buff integrals Gn and Go can be evaluated on the basis of the properties of protein-free mixed solvent water + cosolvent. It should be mentioned that recently the Kirkwood—Buff theory was used to analyze the effects of various cosolvents on the properties of aqueous protein solutions. " ... 

Equations 8 and 9 show that only the derivative /21 is related to the infinitely dilute protein all other quantities in eqs 8 and 9 (cj, Cj, Vi, V3, and Ju) are provided by the protein-free mixed solvent water + cosolvent mixture. 

A similar expression can be written for multiple solvents. Our primary interest is on systems containing a protein (2) in a mixed solvent water (1)—cosolvent (3). An inorganic salt or a small organic molecule is considered as a cosolvent. 

A very illustrative example of the influence the mixed solvent water-methanol has on the precipitation of Gibbsite (Al(OH)3) is found in the patent of Wilhetmy. As shown in Figure 8.19, the particle shape is dramatically influenced by pH (cNaoe) and by the relative amount of methanol. 

Qualitatively similar results were obtained by analyzing the fluorescence of a- and /J-naphthol in mixed-solvent water-alcohols with and without added P-CD. The ionic emission of /J-naphthol was quenched the molecular emission of a-naphthol, absent in water-ethanol, grew, owing to the... 

Clearly, from the point of view of lability, Cu(I) complexes should react fairly fast. As expected, porphyrin complexes of Cu(I) are highly unstable with respect to Cu(II) porphyrins. Cu(I) has been studied in the mixed solvents water-acetonitrile and dimethylformamide-acetonitrile (6). Unlike many other complexes of Cu(I), Cu TMPyP does not disproportionate according to... 

As an example, let us consider mixed solvent water-formie aeid. Both components of the system are subject to autoprotolysis ... 

In the mixed solvents water - non-aque-ous solvent, in spite of its donor and polar properties, water is a preferred solvating agent. This generalization has some exceptions (solvation in systems Ag - HjO -acetonitrile, Cr - HjO - DMSO, F - HjO-eth-ylene glycol). ... 

Figure 9.21. Dependence of stability constants for cadmium thiocyanate complexes on 1/e in mixed solvent water-methanol at 298.15K.

Such approach may by illustrated by dependence of formic acid association constant on temperature and permittivity in mixed solvents water-ethylene glycol, which is approximated from equation... 

FIG U RE 10.4 Comparison between experimental (o) and calculated (solid lines) solubilities of phenacetin (S is the mole fraction of phenacetin) in the mixed solvent water/dioxane is the mole fraction of dioxane) at room temperature. The solubility was calculated using Equation 10.29. 1-activity coefficients expressed via the Flory-Huggins equation, 2-activity coefficients expressed via the Wilson equation. (From C. Bustamante, and P. Bustamante, 1996, Nonlinear Enthalpy-Entropy Compensation for the Solubility of Phenacetin in Dioxane-Water Solvent Mixtures, Journal of Pharmaceutical Sciences, 85, 1109. Reprinted from E. Ruckenstein, and I. L. Shulgin, 2003c, Solubility of Drugs in Aqueous Solutions. Part 2 Binary Nonideal Mixed Solvent, International Journal of Pharmaceutics, 260, 283, With permission from Elsevier.)... 

I. Mixed solvents - water/MEK, water/2-pentanone, water/other higher ketones, water/ethylene glycol methyl butyl ether, water/propylene glycol propyl ether, glycerol/guaiacol, glycerol/m-toluidine, glycerol/ethyl benzylamine, water/pyridines, water/piperidines (International Critical Tables, Volume 111, 1928, pp. 386-398 Seidell and Linke, 1952)... 

DBC complexes with metal salts in the water-benzene system are the products of the interfacial reaction [119]. The measured work of adsorption (15.9 kJ/mol) can be taken as a sum of the free energy of complex formation and work of adsorption of DBC at the water-benzene interface. The dissolution of complexes in bulk phases was neglected. The interfacial constants of complex formation (Table 3) calculated from the work of adsorption are close to the constants determined in the mixed solvent - water-tetrahydrofuran [114]. The only exceptions are the complexes of DBC with Ba " and La salts. Apparently this is due to stronger Coulomb repulsion of ions in DBC-salt complexes at the interface as compared to the bulk phases. (At the interface, the anions... 

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