Baphomet - 27-2-2007 at 03:53
I've got 3 organic substances, with the following melting points:
A: -83c
B: 30c
C: 70c
Fraction 'B' is the compound to be isolated. Both 'B' and 'C' are solvated by 'A' but do not dissolve in each other.
The theory is like this: if the mix is frozen then 'A' can be discarded as a liquid. Then the mix is gently heated above 30c and 'C' solid can be
discarded, leaving 'B'.
Will it work?
[Edited on 27-2-2007 by Baphomet]
Maya - 27-2-2007 at 04:43
Maybe, or maybe not, generally solubility goes down as temperature goes down but not always. Look up differential crystallization techniques. Are your
compounds Organic or Inorganic?
It all depends on the solubility of fractions B & C in fraction A as a function of temerature.
Thats all I can say with certainty about your theoretical problem set w/o further details
chemrox - 27-2-2007 at 23:42
B is the lowest melting right?
If so, why not fractionally distill under vacuum?
YT2095 - 28-2-2007 at 01:42
since A is -83 then cant you just leave the whole thing at room temp for a while as it BP will be presumably lower than the BP of the other 2.
that just leaves B and C to sort out.
do you Have the BP data on these or just the MP data?
Baphomet - 28-2-2007 at 20:45
Thanks guys I tried it but 'A' still had the others in solution at -5c
In the absence of dry ice, a frac dist is the way to go