Although not a solid, a comparable principle has been applied to butyric acid.
Already in 1878, addition of sulfuric acid to aqueous sodium butyrate,
obtained via fermentation,
led to an oily layer of butyric acid on top of the aqueous phase (Benninga, 1990). This indicates that the presence of salts decreases the solubility of otherwise completelymiscible butyric acid. Recently, Wu et al. (2010) showed that in such a system, with CaCl2 as salt, the butyric acid phase will contain less acetic acid than the aqueous phase, thus leading to some purification.