🚀 go-pugleaf

> 
> In article <1990Nov28.203618.7294@arcturus.uucp> graham@arcturus.uucp (Thomas D. Graham) writes:
>>
>>  I have some methanol, but I suspect that it is
>>  contaminated with water.  Could I simply take a small sample, say 2 oz,
>>  burn it and the remaining liquid is water??  Any ideas???  Thanks.
> 
> If you put it in the freezer, wouldn't the water percipitate out as ice?

Alcohol and water mix to form a solution with a lower freezing point than
either substance by itself.  I believe that the ratio that has the lowest
freezing point is known as the "eutectic".

If you have a non-eutictic mixture and cool it, you will see crystals
precipitate out.  If you have too much water these will be mostly-water ice
crystals, if you have too much alcohol these will be mostly-alcohol ice
crystals.  Just before the last of the mixture freezes the remaining liquid
will be a eutectic mixture of alcohol and water.

You could do a rough purification to separate the water and alcohol by
cooling the alcohol-water mixture and lifting out the frozed alcohol so
long as you didn't let the temperature get too close to the eutectic
temperature (and you were sure you only had a little water in the mixture).

This would not be an efficient way to separate the two and probably
would be less efficient than distillation... just buy some new alcohol.