Random - 13-3-2011 at 16:22
I don't have steam distillation apparatus and I am going to do a hoffman degradation of benzamide soon. That would produce Aniline along with some
tar. So, I was thinking about another way of purification:
I would have that solution which would be strongly basic, would contain tar and hypochlorite along with aniline which may not be soluble completely
in water.
1. I would filter it to remove insoluble tar. Then I should get clear solution of aniline, hypochlorite and hydroxide in water along with maybe
insoluble layer of some aniline.
2. Some way is required to destroy excess hypochlorite. Then I would add hydrochloric acid to the mixture to dissolve aniline which was insoluble.
3. Into the solution of aniline hydrochloride I would add zinc chloride to make insoluble double salt of aniline zinc hydrochloride.
4. Collect insoluble salt, add sodium hydroxide to make zinc hydroxide from that salt and again free aniline.
4. To a mixture of aniline, zinc hydroxide and water I would add NaCl, aniline would salt out and it should flow on the water while zinc hydroxide
should settle to bottom.
5. Separate layer, done.
Maybe this thread could help those who don't have steam distillation setup to purify it.
Now I have 2 questions:
How to destroy excess hypochlorite so it won't release Cl2 when I add HCl?
Is anline zinc double salt insoluble or slightly soluble in water? If it is slightly soluble, how much?
Chordate - 13-3-2011 at 16:52
Are you sure you don't have a steam distillation setup? Steam distillation can be done by done in a regular distillation setup by adding water to the
mixture and distilling, or even more effectively by running a piece of heater hose from the outlet of a pressure cooker into the reaction mixture.
See this link for the pressure cooker method
Or this one ref for the one pot setup
Magpie - 13-3-2011 at 19:53
Are you sure that there will be hypochlorite remaining? I'm just speculating that you may be able to use the same technology as that used to make
hydrazine from urea via the Hofmann degradation.
See: http://www.sciencemadness.org/talk/viewthread.php?tid=15091
Random - 14-3-2011 at 00:07
Actually, the problem is that I don't have any distillation setup, I don't have any glassware except test tubes. The only distillation setup I could
make would be 2 test tubes and a pvc tubing between that.
Magpie, I think there would be some excess hypochlorite, because in your method hypochlorite decomposes with urea, forming along some hydrazine. But
that would just contaminate the solution even more.