Hexane and water are only partially miscible, whereas acetone is soluble in both. Are you looking for vapor-liquid (VLE) or liquid-liquid (LLE) or vapor-liquid-liquid (VLLE) equilibrium data? If no data exists, you may have no option but to estimate the equilibrium from UNIFAC.
Be careful, though, as UNIFAC is not guaranteed to be accurate enough for process design quality simlations. Also, there are separate UNIFAC group interaction tables for VLE and LLE.
