Recrystallization solubility data

Thermodynamic calculations based on the compositional dependence of the equilibrium constant are applied to solubility data in the KCl-KBr-H20 system at 25°C. The experimental distribution coefficient and activity ratio of Br /Cl in solution is within a factor of two of the calculated equilibrium values for compositions containing 19 to 73 mole percent KBr, but based on an assessment of uncertainties in the data, the solid solution system is clearly not at equilibrium after 3-4 weeks of recrystallization. Solid solutions containing less than 19 and more than 73 mole percent KBr are significantly farther from equilibrium. As the highly soluble salts are expected to reach equilibrium most easily, considerable caution should be exercised before reaching the conclusion that equilibrium is established in other low-temperature solid solution-aqueous solution systems. 

The methods that have been used to purify metal derivatives of jS-keto imines are surprisingly limited. Generally, recrystallization has been used, with acetone, ethanol, and benzene as common solvents. Very few quantitative solubility data are available. However, the solubilities of 4,4 -(ethylenedinitrilo)di-2-pentanonatocopper(II) and its 1-hydrate in water and in 12% ethanol have been determined at several temperatures. ... 

LynestrenoL Lynestrenol (73) has been used in oral contraceptives and to treat menstrual disorders. It is converted in vivo to its active metabohte norethindrone (102,103). It can be recrystallized from methanol, and is soluble in ethanol, ether, chloroform, and acetone, and insoluble in water (102). The crystal stmcture (104) and other spectral and analytical data have been reported for lynestrenol (62). 

Otsuka et al. (107) describe [Ni(CNBu )2], as a reddish brown microcrystalline substance, which is extremely air-sensitive. It can be recrystallized from ether at —78°C, and is soluble in benzene in the latter solution the infrared spectrum (2020s, br, 1603m, 1210m) and proton NMR (three peaks of equal intensity at t8.17, 8.81, and 8.94) were obtained. Neither analytical data nor molecular weight is available on this complex. The metal-ligand stoichiometry is presumably established by virtue of the molar ratio of reactants and by the stoichiometries of various reaction products. 

The absorption spectral data agree well with those reported for the chloride salt. The nitrate salt is sparingly soluble in water (0.346 g in 100 mL of water at 7°) and can be recrystallized from hot water. The chloride salt is much more soluble in water. 

This relatively stable compound can be recrystallized from water and has a water solubility of 1,3 X 10 mol r at 25°C. The X-ray-data show two molecules together with two molecules of water in an asymmetric unit. Further investigations on H-bonding in the crystal lattice are in... 

Examples of homoleptic bismuth selenolates Bi(SeR)3 are few. Three compounds 1-3 are known, which are prepared by treating Bi[N(SiMe3)2]3 with the corresponding areneselenols in light petroleum. They are colored yellow to red, air-stable in the solid state, and can be sublimed at moderate temperatures. They are soluble in common organic solvents and a mixture of MeCN and ethyl acetate is the solvent of choice for recrystallization [95JCS(D)1649]. H- and C-NMR data of these compounds are available chemical shift values are similar to those of the corresponding thiolates. 

Solution stability is important not only for solution or suspension products, but can also impact other properties such as solubility and dissolution data for other types of dosage forms. The effects of dissociation, recrystallization, ionization, complexation, and solution chemistry are all areas that will need further work to understand better how co-crystals will behave in various media. 

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