Dimethyl formamide solubility parameter

Solvatochromic Approach Solvatochromic relationships are multivariate correlations between a property, usually solubility or partitioning property (see Sections 11.4 and 13.3), and solvatochromic parameters, parameters that account for the solutes interaction with the solvent. In the case of vapor pressure, the solvatochromic parameters only have to account for intermolecular interaction such as selfassociation between the solute (i.e., pure compound) molecules themselves. The following model has been reported for liquid and solid compounds, including hydrocarbons, halogenated hydrocarbons, alkanols, dialkyl ethers, and compounds such as dimethyl formamide, dimethylacetamide, pyridine, and dimethyl sulfoxide... 

From these data it is suspected that the molecules of the solvate structure of lithium ion might be largely effected by the solvent molecules. Since the solubility of some lithium salts is relatively high in MN-dimethyl formamide (DMF), concentrated solutions can also be examined. In a previous study the solvate structure of lithium has been described in an 1.5 mol dm LiNCS solution in DMF [38]. A new XD measurement has been carried out for a LiCl solution of the same concentration. Table 1 hows the structural parameters for the lithium solvates in both solutions. The structural parameters were determined by a least-squares fitting method (LSQ). After the subtraction of the contributions ascribed to the intramolecular stmcture of the DMF molecules and to the assumed structure around the anions from the total structure function of the solution, the resulted difference curve was approximated by calculated model curves. The result is shown in Figure 1. 

Physical Parameters. Metronidazole is obtained as cream-coloured crystals having mp 158-160°C. Its solubility at 20°C (g/100 ml) water 1.0 ethanol 0.5 ether < 0.05 and chloroform < 0.05. It is found to be sparingly soluble in dimethyl formamide (DMF) and soluble in diluted acids. The pH of a saturated aqueous solution stands at 5.8. 

Similar reasoning applies to mixtures of solvents. The combination of a nonsolvent with a lower, and a nonsolvent with a higher, solubility parameter than that of the polymer often gives a good solvent for the polymer (Table 6-4). Conversely, a mixture of two solvents can be a nonsolvent. Poly(acrylonitrile) 62 = 12.8), for example, dissolves in both dimethyl-formamide (<5i = 12.1) and malodinitrile = 15.1), but not in a mixture of the two. 

In the thermodynamics of polymer blends the solubility parameter is the most important parameter describing the miscibility between component polymers. However, this parameter is insufficient to explain the above finding. The samples were prepared in the form of film by casting from dimethyl formamide (DMF) solution. The values of solubility parameters are 14.7, 18.93, and 24,8x10 ... 

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