One of the questions in my 15-year-old son's chemistry textbook asks, "How
would you separate [solid] sodium chloride and sucrose using the solvent
ethanol". The answer I think they want is that you dissolve out the sucrose
with the ethanol, which is subsequently evaporated off. I suspect this is an
error - I've already spotted a couple of others - because the book states a
few pages earlier that sucrose is soluble in ethanol. Data in Beilstein and
the International Critical Tables suggest that the solubility of sucrose in
anything like pure ethanol is very small. Comparison with solubility data
for NaCl from Linke suggests that the separation as described is impossible.
Has anyone any experience of the solubility of sucrose in ethanol or, more
likely, in denatured ethanol (industrial methylated spirits)?
How would *you* separate solid sucrose and NaCl? I favour some sort of
density separation, based on a heavy liquid with a density around 1.8 g/cm3
(CCl4 with a little CH2I2?)
Has anyone any wacky ideas for actually using ethanol as the separation
medium? (Countercurrent separation, again based on the density?)