Solubility of organic compounds

Partly because of its fall in polarity with increased temperature, superheated water can dissolve organic compounds to some extent, especially if they are shghtly polar or polarizable, as are aromatic compounds. The solubihty of an organic compound in superheated water is often many orders of magnitude higher than its solubility in water at ambient temperature for two reasons, one being the polarity change. 

The other is that a compound with low solubihty at ambient temperature will have a high positive enthalpy of solution, and thus a large increase in solubihty with temperature. 

%2 is the mole fraction of the solute in the solution, Tq is a temperature near ambient at which the solubility is known and T the temperature of the required solubility. Comparisons of predictions from this equation for choranthonil, the worst fitting compound, are given in Table 3.8-1. Agreement within a factor of about 5 was obtained, although the solubihties rise by several orders of magnitude over the temperature range. 

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Divide the saturated solution of n-butyl alcohol in water into three approximately equal parts. Treat these respectively with about 2-5 g. of sodium chloride, potassium carbonate and sodium hydroxide, and shake each until the soli have dissolved. Observe the effect of these compounds upon the solubility of n-butanol in water. These results illustrate the phenomenon of salting out of organic compounds, t.e., the decrease of solubility of organic compounds in water when the solution is saturated with an inorganic compound. The alcohol layer which separates is actually a saturated solution of water in n-butyl alcohol. 

Non-aqueous microemulsions have been prepared by replacing water with formamide, a highly structured polar solvent [71]. Formamide enhances the solubility of organic compounds and is also used as a reactant. 

Balakin KV, Ivanenkov YA, Skorenko AV, Nikolsky YV, Savchuk NP, Ivashchenko AA. In silico estimation of DMSO solubility of organic compounds for bioscreening. J Biomol Scr 2004 9 22-31. 

Catana, C., Gao, H., Orrenius, C., Stouten, P. F. Linear and nonlinear methods in modeling the aqueous solubility of organic compounds. 

S. Prediction of aqueous solubility of organic compounds using a quantitative structure-property relationship. J. Pharm. Sd. 2002, 91,1838-1852. 

Wakita, K., Yoshimota, M., Miyamoto, S., Watanabe, H. A method for calculation of the aqueous solubility of organic compounds by using new fragment solubility constants. Chem. Pharm. Bull. 1986, 34, 4663 681. 

Metal ions in aqueous solution exist as complexes with water. The solubility of organic compounds in water depends primarily on their polarity and their ability to form hydrogen bonds with water. Organic compounds with a large part of polar components such as acetic acid, dissolve in water without limit. In such cases, the polar part dominates. By contrast, soaps and detergents have a polar end attached to a relatively large nonpolar part of the molecule. They have limited solubility and the molecules tend to coalesce to form micelles. 

Solubility of the water/benzene system (taken from Seidell, A. S., Solubilities of Organic Compounds, 3rd edn, Vol. II, 1941, Van Nostrand). 

Prediction of aqueous solubility of organic compounds from molecular structure, J. Chem. Inf. Comput. Sci. 1998, 38, 489-496. 

Baneijee, S. (1985) Calculation of water solubility of organic compounds with UNIFAC-derived parameters. Environ. Sci. Technol. 19, 369-370. 

Wasik, S.P., Tewari, Y.B., Miller, M.M., Martire, D.E. (1981) Octanol/Water Partition Coefficients and Aqueous Solubilities of Organic Compounds. NBSIR 81-2406, report prepared for Office of Toxic Substances, Environmental Protection Agency, Washington, DC. 

Etzweiler, F., Senn, E., Schmidt, H.W.H. (1995) Method for measuring aqueous solubilities of organic compounds. Anal. Chem. 67, 655-658. 

Nirmalakhandan, N.N. and Speece, R.E. Prediction of aqueous solubility of organic compounds based on molecular structure. Environ. Sci. Technol, 22(3) 328-338, 1988a. 

Brooker, P.J. and Ellison, M. The determination of the water solubility of organic compounds by a rapid turbidimetric method, Chem. Ind., (October 1974), pp. 785-787. 

Lyubartsev, A.P., Jacobsson, S.P., Sundholm, G and Laaksonen, A. Solubility of organic compounds in water/octanol systems. An expanded ensemble molecular dynamics simulation study of log Pparameters, J. Phys. Chem. B, 105(32) 7775-7782, 2001. 

Palit, S.R. Electronic interpretations of organic chemistry. II. Interpretation of the solubility of organic compounds, J. Phys. C/tem, 51(3) 837-857, 1947. 

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