Predicting solubility of ionic compounds in ionic liquids

[uby]

This question probably belittles the complexity of the issue, but I thought I'd ask anyway:

Are there any reasonable methods by which the solubility of ionic compounds (e.g., KCl, NaBr, CaO, etc.) in ionic liquids (e.g., 1-ethyl-3-methylimidazolium tetrafluoroborate, tetrabutylammonium bromide) can be predicted? For example, if I wanted to maximize the concentration of dissolved KCl, I'd like to have some guidelines to follow by which I can select the most appropriate ionic liquid.

Given that the ionic liquids can display such low melting temperatures due to the asymmetry and conformational flexibility of its constituent ions, I'd guess that the dissolution and dissociation of solid ionic compounds would be a complex process with difficult-to-predict ionic mixing/coordination in the liquid.

 

[Mike H]

I recall this mention of there finally being enough data for gases dissolved in ionic liquids (ILs) to establish a "test set" to assess computational models the other year. Most of what I have seen in terms of rationalizing the solubility characteristics of ILs are in relation to its role in "greening" up synthetic chemistry and its applications (mixtures with organic solvents; various common synthetic starting materials and products/intermediates; and so on). Weirdly, I do recall interest in ILs with regard to lanthanide and actinide chemistry (including environmental applications), which is probably the closest to your inquiry about ionic compounds in ionic liquids. I am fairly certain it was not at the pithy "here are a few rules to remember" level, though.

I've never worked with ILs in any substantive manner, so hopefully someone more experienced will come around on this topic. Also, if you want me to run down my partially jogged memory for citations for the above, let me know.

 

[uby]

I recall this mention of there finally being enough data for gases dissolved in ionic liquids (ILs) to establish a "test set" to assess computational models the other year. Most of what I have seen in terms of rationalizing the solubility characteristics of ILs are in relation to its role in "greening" up synthetic chemistry and its applications (mixtures with organic solvents; various common synthetic starting materials and products/intermediates; and so on). Weirdly, I do recall interest in ILs with regard to lanthanide and actinide chemistry (including environmental applications), which is probably the closest to your inquiry about ionic compounds in ionic liquids. I am fairly certain it was not at the pithy "here are a few rules to remember" level, though.

I've never worked with ILs in any substantive manner, so hopefully someone more experienced will come around on this topic. Also, if you want me to run down my partially jogged memory for citations for the above, let me know.

Thanks Mike. Your suggestion regarding actinide/lanthanide chemistry in ionic liquids has turned up some interesting results!