Solubility concept

Practical Solubility Concepts. Solution theory can provide a convenient, effective framework for solvent selection and blend formulation (3). When a solute dissolves in a solvent, a change in free energy occurs as a result of solvent—solute interactions. The change in free energy of mixing must be negative for dissolution to occur. In equation 1,... 

The solubility parameter of water is 17 or 23, depending on the association structure of water used in the calculation. None of the values listed in Table II are within two units of either value and by the general rules of the solubility concept, none of the polymers in Table II should be water soluble. Homopolymers of monomers c, e, or f in Figure 3 are not water soluble. The solubility values listed for the W-SPs studied do not correlate with the equilibrium pressures observed. A general correlation is noted if the values of the most hydrophobic segments (i.e., the oxypropyl, oxybutyl and acetate) are compared with PMVE. The... 

G. L. Flynn. Solubility concepts and their applications to the formulation of pharmaceutical systerms. I. Theoretical foundations. J. Parent. Sci. Technol. 38 202-209, 1984. 

Functional groups Chapter 3 uses the functional groups to introduce important properties of organic chemistry. Relevant examples—PCBs, vitamins, soap, and the cell membrane—illustrate basic solubility concepts. In this way, practical topics that are sometimes found in the last few chapters of an organic chemisuy text (and thus often omitted because instructors run out of time) are introduced early so that students can better grasp why they are studying the discipline. 

Blasko A, Leahy-Dios A, Nelson W, Austin S, Killion R, Visor G, and Massey I. Revisiting the Solubility Concept of Pharmaceutical Compounds. Monat Ghent 2001 132 789-798. 

Flynn GL. Solubility Concepts and Their Applications to the Formulation of Pharmaceutical Systems. J Parent Sci Technol 984 38(5) 202-209. 

For several polymer-polymer systems the interaction energies were estimated from structure of polymer repeat units using the solubility concept [Shaw, 1974], The methods of calculation of 5 for various polymers and blends was also published [Van JCrevelen and Hoftyzer, 1976 Olabisi et al., 1979],... 

Application of the solubility concept in liquid-liquid extraction. H. M. N. II. Irving, Ion Exch. Solvent Extr., 1974,6, 140-187 (61). 

Coating and paint formulations, adhesives, polymer-plasticizer compatibility and solvent effects on plastic surfaces are only a few of the areas that can benefit from the Hansen solubility parameter theory. Hansen [1] extended the solubility concepts discussed in Chapter 4 to include resin and polymeric materials. The total solubility parameter of a polymer is the point in three-dimensional space where the three partial solubility parameter vectors meet as the center point of the idealized spherical envelope. The distance in space between the two sets of parameters (solvent and polymer) can be represented by the term, radius of interaction or R. The radius of interaction term is used to express the degree of mutual solubility. All of these solubility comparisons can be made by using computer spreadsheets that are described in Chapters 4, 19, and this chapter. 

McGUnchey, C. (2002). Boundaries of the Teas solubility concept. Western Association for Art Conservation Newsletter, 24(2), 17-19. 

Molecular Weight Cutoff The best-known method for characterizing UF membranes is molecular weight cutoff. Unfortunately, it is widely misunderstood and has been the source of much error. The concept of molecular weight cutoff (MWCO) is powerful and deceptively simple. Ultrafilters retain soluble molecules, so their retention is... 

The solubility parameter concept has found widespread use in predicting the compatibility of components used in paints and coatings, and the patent literature contains numerous references to the solubility parameter or solubility parameter ranges in specifying formulations. Its use in predicting adhesion should apply in... 

Hansen [137-139], and later van Krevelen [114] proposed the generalization of the solubility parameter concept to attempt to include the effects of strong dipole interactions and hydrogen bonding interactions. It was proposed that the cohesive energy density be written as the sum of three terms, viz. 

The term solubility thus denotes the extent to which different substances, in whatever state of aggregation, are miscible in each other. The constituent of the resulting solution present in large excess is known as the solvent, the other constituent being the solute. The power of a solvent is usually expressed as the mass of solute that can be dissolved in a given mass of pure solvent at one specified temperature. The solution s temperature coefficient of solubility is another important factor and determines the crystal yield if the coefficient is positive then an increase in temperature will increase solute solubility and so solution saturation. An ideal solution is one in which interactions between solute and solvent molecules are identical with that between the solute molecules and the solvent molecules themselves. A truly ideal solution, however, is unlikely to exist so the concept is only used as a reference condition. 

There have been many attempts to divide the overall solubility parameter into components corresponding to the several intermolecular forces. For example, a so-called three-dimensional solubility parameter concept is built on the assumption that the ced is an additive function of contributions from dispersion (d), polar (p), and H-bonding (h) forces. It follows that... 

Temperature-dependent phase behavior was first applied to separate products from an ionic liquid/catalyst solution by de Souza and Dupont in the telomerization of butadiene and water [34]. This concept is especially attractive if one of the substrates shows limited solubility in the ionic liquid solvent. 

When water-miscible ionic liquids are used as solvents, and when the products are partly or totally soluble in these ionic liquids, the addition of polar solvents, such as water, in a separation step after the reaction can make the ionic liquid more hydrophilic and facilitate the separation of the products from the ionic liquid/water mixture (Table 5.3-2, case e). This concept has been developed by Union Carbide for the hydroformylation of higher alkenes catalyzed by Rh-sulfonated phosphine ligand in the N-methylpyrrolidone (NMP)/water system. Thanks to the presence of NMP, the reaction is performed in one homogeneous phase. After the reaction. 

In comparison with classical processes involving thermal separation, biphasic techniques offer simplified process schemes and no thermal stress for the organometal-lic catalyst. The concept requires that the catalyst and the product phases separate rapidly, to achieve a practical approach to the recovery and recycling of the catalyst. Thanks to their tunable solubility characteristics, ionic liquids have proven to be good candidates for multiphasic techniques. They extend the applications of aqueous biphasic systems to a broader range of organic hydrophobic substrates and water-sensitive catalysts [48-50]. 

The great importance of the solubility product concept lies in its bearing upon precipitation from solution, which is, of course, one of the important operations of quantitative analysis. The solubility product is the ultimate value which is attained by the ionic concentration product when equilibrium has been established between the solid phase of a difficultly soluble salt and the solution. If the experimental conditions are such that the ionic concentration product is different from the solubility product, then the system will attempt to adjust itself in such a manner that the ionic and solubility products are equal in value. Thus if, for a given electrolyte, the product of the concentrations of the ions in solution is arbitrarily made to exceed the solubility product, as for example by the addition of a salt with a common ion, the adjustment of the system to equilibrium results in precipitation of the solid salt, provided supersaturation conditions are excluded. If the ionic concentration product is less than the solubility product or can arbitrarily be made so, as (for example) by complex salt formation or by the formation of weak electrolytes, then a further quantity of solute can pass into solution until the solubility product is attained, or, if this is not possible, until all the solute has dissolved. 

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