How do I predict the solubility of a compound in a mixture of water and an organic co-solvent?

I'm trying to predict the solubility of long alcohols (e.g. 1-octanol, 1-decanol or 1-dodecanol) in a mixture of water and an organic co-solvent such as DMSO, acetonitrile or ethyl acetate.


For example, decanol in water with 25% DMSO or saturated with ethyl acetate (8.3%). I of course know the solubility of alcohols in water, but not in organic solvents or in mixtures.


I found a server to predict the solubility of any compound in any solvent, but I'm not sure how accurate it is and it only does predictions for pure solvents, not mixtures: <http://showme.physics.drexel.edu/onsc/models/multisolvent.php>


Any input on this would be greatly appreciated!




I think this is very much an open problem. As you may see from the Drexel pages, even solubility prediction in *one* solvent is still fairly hard, partly because of the lack of experimental data.


The only software that I know capable of making predictions about solubility in mixed solvents is [COSMOtherm](http://www.cosmologic.de/products/cosmotherm.html), based on the [COSMO solvation model](http://en.wikipedia.org/wiki/COSMO_Solvation_Model).


I have never used it, but the capability is mentioned on the website.


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I would be surprised if you found anything predicting solubility in mixtures as there is poor modelling due to non-linear effects. Taking solubilities of two solvents and trying to interpolate does not work. As little as a few hundred ppm to 4% of one solvent in another is enough to confound standard predictive equations without empirical data. 


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