Organics, solubility group contribution methods

Ktihne, R., Ebert, R.-U., Kleint, F., Schmidt, G., Schuurmann, G. (1995) Group contribution methods to estimate water solubility of organic chemicals. Chemosphere 30, 2061-2077. 

Baner, A. L. The estimation of partition coefficients, solubility coefficients and permeability coefficients for organic molecules in polymers using group contribution methods. New Developments in the Chemistry of Packaging Materials. ACS Symposium Dallas 1998. ACS Symposium Series, ACS Washington D.C. 1999. 

Goydan. R Reid, R.C., Tseng, H. Estimation of the solubilities of organic compounds in polymers by group-contribution methods. Ind. Eng. Chem. Res., 1989.28 445-454. 

Banneijee (h) determined the solubilities of mixtures of several chlorobenzenes with one another and with toluene and benzyl alcohol. The results agreed satisfactorily with predictions from equation (8). The water phase activity coefficients were obtained from the pure component solubilities via equation (6). The organic phase activity coefficients for mixtures of chlorobenzenes with hydrocarbons were predicted by the UNIFAC group contribution method. Mixtures containing only chlorobenzenes were essentially ideal, Yi = When benzyl alcohol was used as a cosolute, the agreement with equation (8) was improved by using UNIFAC to predict the activity coefficient in the aqueous phase. 

The key to the use of equation 3.25 for the prediction of solubilities in non-ideal systems is a reliable estimation of the activity coefficient 7. For organic solutes in organic solvents, this may be achieved (Gmehling, Anderson and Prausnitz, 1978) by the UNIFAC group contribution method which is discussed, together with other techniques for the prediction of solubility data, in section 3.10. 

To estimate the solubility of an organic solid solute in a solvent it is only necessary to know its melting point, enthalpy of fusion and relevant activity coefficient. Gmehling, Anderson and Prausnitz (1978) have shown that this activity coefficient can be estimated by the UNIFAC group contribution method, and they report a number of cases where the solubilities of a variety of organic solids in single and mixed solvents are accurately predicted. Even eutectic temperatures and compositions may be estimated for some binary systems. 

Goydan R et al. (1989) Estimation of the Solubilities of Organic Compounds in Polymers by Group-Contribution Methods. Ind Eng Chem Res 28 445... 

Different types of equations of state have been used to model the phase behaviour of ionic liquid systems. Cubic equations of state such as the Peng-Robinson equation and the Redlich-Kwong equation have been used to describe the solubility of carbon dioxide, trifluoromethane and organics in ionic liquids. Because cubic equations of state require the critical parameters of ionic liquids, which are unknown, these have to be estimated by using group-contribution methods. Thus estimates obtained from cubic equations of state for ionic liquid systems are unreliable. Moreover, cubic equations of state can only describe the carbon dioxide solubility in ionic liquids at low concentrations, but cannot predict the dramatic increase in bubble point pressure at higher carbon dioxide concentrations. ... 

The UNIFAC (UNIQUAC functional group activity coefficient) method is an extension of the UNIQUAC (Universal quasi chemical) method, which has been used widely in chemical process engineering to describe partitioning in organic systems as occur in petroleum and chemical processing (Fredenslund et al., 1975,1977). It has been applied less frequently to aqueous systems. It expresses the activity coefficient as the sum of a "combinational" component, which quantifies the nature of the area "seen" by the solute molecule, and a "residual" component, which is deduced from group contributions. Arbuckle (1983,1986), Banerjee (1985), Banerjee and Howard (1988), and Campbell and Luthy (1985) have tested the applicability of the method to water solubility. 

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