gilgamesh - 29-6-2005 at 11:11
I found a paint thinner on the shelves today that contains toluene, acetone and isopropylalcohol. Are there any azeotropes between toluene and any of
the other 2 chemicals?
trilobite - 29-6-2005 at 13:38
Here you go: http://eweb.chemeng.ed.ac.uk/chem_eng/azeotrope_bank.html
gilgamesh - 30-6-2005 at 13:13
Thanks a lot
Apparently there are no azeotropes between toluene and acetone or isopropanol.
With a boiling point for toluene at 111 vs. 82 for isopropanol and 56 for acetone it sounds feasible to separate the toluene by fractional
distillation (Maybe even simple distillation if isopropanol content is fairly low - a drawback of course is that toluene's molar weight is quite
a bit larger than isopropanol ... an equimolar mixture contains a lot more toluene than isopropanol by weight or volume.
Anybody got any ideas for removing the isopropanol without affecting the toluene - perhaps with KMnO4 or bleach? Perhaps even refluxing with sulphuric
acid to create an ether?
[Edited on 30-6-2005 by gilgamesh]
neutrino - 30-6-2005 at 16:23
Add water. Isopropanol and acetone will dissolve, toluene won't. You should end up with a layer of toluene and one of water/alcohol/acetone.
gilgamesh - 30-6-2005 at 22:46
Hmm perhaps that would work, if affinity for water is greater than for toluen.
Good news is that the most troublesome molecule isopropanol should have greater affinity for water than acetone.
Does anybody have any idea where the equilibrium between water phase and toluen phase is for isopropanol and acetone?
(It would probably be easy to see how much the volume of the thinner decreases when mixed with water, but unless I know the actual toluene content it
won't help me much)
trilobite - 1-7-2005 at 08:08
You wash it repeatedly with water, all the isopropanol and acetone will eventually be extracted, as multiple extractions are much more effective than
a single one. That's the normal procedure.
sparkgap - 1-7-2005 at 22:17
"...multiple extractions are much more effective than a single one..."
Do keep in mind that the "law of diminishing returns" is applicable to extractions... 
sparky (~_~)