Solubility parameters for some common solvents

As discussed earlier, solubility parameter is important when nonpolar solvents are mixed. Table 7 provides a list of molar liquid volume and solubility parameter for some common solvents. Aromatics have a higher value of this parameter compared to the aliphatics. 

Table 2. Solubility parameters for some common solvents.

Tables 3.3 and 3.4 list solubility parameters for some common solvents and polymers [17,18]. The units of 6 are in (energyA olume) / and those tabulated in cal / cm / are called hildebrands. The SI value in may be obtained by multiplying the 6 value in hildebrand by 2.045. Most tabulated solubility parameters refer to 25°C. It is believed that the temperature dependence of 6 can be neglected over the range normally encountered in industrial practice.

Table 3.3 Solubility Parameters for Some Common Solvents ...

Table 12-3 lists solubility parameters for some common polymers and solvents. The units of S are in (energy/volume) and those tabulated, in cal cm /, are called hildebrands. 

Tfaeie have been a number of attempts to develop solvent parameter scales that could be used to correlate ttiermodynamic and kinetic results in terms of these patametois. Gutmann s Donor Numbers, discussed previously, are sometimes used as a solvent property scale. Kamlet and Taft and co-workers developed the solvatochromic parameters, Uj, B, and n that are related to the hydrogen bonding acidity, basicity and polarity, respectively, of the solvent. Correlations with these parameters also use the square of tte Hildebrand solubility parameter, (5, that gives the solvent cohesive energy density. Parameters for some common solvents are collected in Table 3.6. 

Estimates of solubility parameters for a variety of liquids are available in the literature. Table 4.1.6 illustrates the values of solubility parameters for some common liquids. If the solute prefers the solvent (phase 1, species 3), then <5,-is closer to S3 than S, and therefore, X) > 1. (Note Generally, the more polar the liquid, the larger the value of the solubility parameter water, which is highly polar, has a <5,-of 21, whereas n-pentane, which is extremely nonpolar, has a 3i of only 7.1. Further, the higher the required energy of vaporization, the higher the solubility parameter.)... 

Table 8.2 Values of the Cohesive Energy Density (CED) for Some Common Solvents and the Solubility Parameter 6 for These Solvents and Some Common Polymers...

The other two parameters are defined similarly the sum of the three parameters is thus normalized to 1. Values for some common solvents are listed in Table 15 (along with the Hildebrand solubility parameters and the Snyder solvent strength parameters). 

Where 8, 8 and 8, are the solubility parameters corresponding to the non-poiar (dispersion) contribution, polar contribution and hydrogen bond contribution respectively. Values of the Hansen solubility parameter 8 for some common solvents as well as their 8, 8 and 8j vaiues are shown in Table 4.1. In the Hansen system, solvents are represented as a single spot in the three dimensional model, while polymers are represented by a volume. Solvents that have their spot within this volume dissolve the polymer, while solvents lying outside the volume will not. For mixed solvents, a weighted average of the three partial solubility parameters can be calculated. 

Some values of 5 for a range of solvents are given in Table 1, and some for some common polymers appear in Table 2. In both cases, substances are listed in order of increasing solubility parameter. 

Regular solution theory, the solubility parameter, and the three-dimensional solubility parameters are commonly used in the paints and coatings industry to predict the miscibility of pigments and solvents in polymers. In some applications quantitative predictions have been obtained. Generally, however, the results are only qualitative since entropic effects are not considered, and it is clear that entropic effects are extremely important in polymer solutions. Because of their limited usefulness, a method using solubility parameters is not given in this Handbook. Nevertheless, this approach is still of some use since solubility parameters are reported for a number of groups that are not treated by the more sophisticated models. 

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