Ylang-Ylang
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separation of mononitrotoluenes
Just wondering, if toluene is mononitrated, will the p-nitrotoluene just fall out? It's said to have a melting point of 50 C.
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madscientist
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It won't. It dissolves into the mixture of other mononitrated toluenes.
I weep at the sight of flaming acetic anhydride.
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Ylang-Ylang
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Can it be crystallized out somehow, I wonder? I searched for awhile but to no great avail. Some russian papers in inaccessible journals, as usual. I
heard something about that crystallization will work, but that is all. I imagine it is similar to the problem of separating xylenes, but I know
similarly little about that.
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Marvin
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The generally accepted method seems to be to steam distill and dry the mononitrotoluene mixture, followed by distilling it with a column. A mixture
of ortho comes over first, then a mixture of meta and ortho and the distillation is continued until the contents of the still have a setting point of
40C and which is then distilled directly into the reciever leaving only tar. The crude p isomer is purified by crystalisation from its melt.
Attempting to do this without the distillation step would probably turn out to be a giant waste of time.
The crude mixture will probably be of the order 2 parts ortho, 1 part para and 1/10th part meta.
[Edited on 9-10-2003 by Marvin]
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KABOOOM(pyrojustforfun)
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toluene nitration products:
<i>o</i>-nitrotoluene 50-60% mp -9.3°C, bp 220.4°C
<i>p</i>-nitrotoluene 40% mp 51.7°C, bp 238.3°C
<i>m</i>-nitrotoluene 3-4% mp 15°C, bp 232.6°C
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ghost711
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If you are using straight nitric to form your nitro species- afterwards you can use 1.5 parts potassium nitrate to nitric acid..heat until the salt
dissolves (75 C)and the organics will phase separate. (Not sure if this method can be used w/mixed acids) This will leave a heavy salt/acid layer left
over which can then be extracted one more time with toluene to remove the residual nitro compounds. Finally the acid/salt layer can be mixed with
sulfuric and either distilled with vacuum very carefully- or better yet extracted with DCM to form pure nitric acid.
[Edited on 12-10-2003 by ghost711]
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ssn688
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Greetings!
This is my first time here and what do I find!
COOL stuff.
I'm a 1st year uni student and we have just learned about activating and deactivating groups on the benzene ring, I thought that a ortho parra
director would block any substitution at the meta site, as the stabilized cation passes through the meta positions. The more I learn the more I
realize I don't know..heheh.
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vulture
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ssn688, this is about mononitrotoluene, I guess you've mixed this up with further nitration of toluene and where the other NO2 groups end up.
Don't worry, the moment you realize you don't know everything, is the moment when you really start learning.
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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ssn688
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ohh..
-------------------------------
Please refrain from making useless posts like this. - Vulture
[Edited on 19-10-2003 by vulture]
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