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If a mixture of water with acetone, methanol, ethanol, or other water miscible solvent, is cooled below 0 degrees, would the water freeze and aggregate out as ice, separating out of the mixture. Or would the frozen 'water particles' be dissolved in the solvent, similar to how solid organics dissolve in solvents?
I suppose it really depends on the concept of solubility vs miscibility. I've been researching this for a while now and haven't been able to find a clear definite answer.
The short answer is
Yes
This is exactly how acetic acid is purified: Acetic acid freezing distilation
In this case, acetic acid (freezing point $16\ ^\circ \text{C}$) freezes first, leaving a water-enriched fluid behind. Conceivably you could remove water from methanol or acetone in the same way (except that water would freeze first). In practice, fractional distillation can be done more economically on a large scale. Fractional distillation requires 1 step (with lots of theoretical plates), while you need to repeat fractional freezing multiple times to get to high purity. Acetic acid is purified by fractional freezing perhaps because it may azeotrope with water.
