ANFO_
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Thoughts on quaternary ammonium compound synthesis
The textbook reaction for forming a quaternary ammonium compound is the heating of an alkyl halide with a tertiary amine (trimethylamine).
Trimethylamine can be synthesized according to this link which I found elsewhere on the forum http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV1...
I haven't worked out the specifics of the next step yet, but methyl iodide is then added to the trimethylamine and the mixture is heated under reflux
which should yeild tetramethylammonium iodide.
A unique feature of quaternary ammonium compounds is that addition of a base doesn't liberate a free amine but rather results in an equilibrium
mixture containing tetramethylammonium hydroxide. In order to displace the equilibruim, an aqueous solution of silver hydroxide is used because it
forms a silver halide which precipitates favoring the forward reaction until completion:
(CH3)4NI + AgOH ------> (CH3)4NOH + AgI
This can then be made into the nitrate by neutralization reaction with nitric acid.
Thoughts on this procedure? (mainly on the middle methylation step) 
[Edited on 23-10-2012 by ANFO_]
[Edited on 23-10-2012 by ANFO_]
[Edited on 23-10-2012 by ANFO_]
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UnintentionalChaos
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"refluxing trimethylamine" is 3C. This can be done under pressure, I suppose, but the chloride salt is not too hard to come by. I'm unsure of solvent
choice that may increase the reaction temp, but you'd want a polar aprotic.
Did you want N(Me)4NO3? Why use Ag2O. Just use AgNO3 and filter off the AgI (or AgCl).
[Edited on 10-23-12 by UnintentionalChaos]
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
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ANFO_
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Thanks for the pointers
Is it possible that the methylation reaction could occur in the gaseous phase, under pressure? Or am I just being hopeful.
For the solvent I could try using DMF.
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Nicodem
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Is there any reason on why you don't follow a published procedure? You might get a more useful reply after you first explain what you find wrong with
the known procedures.
Also, why you would want to use DMF? It is the last choice solvent for such a reaction. I would expect THF, acetone or acetonitrile, but not DMF,
because Me4NI could have too much of a solubility in it, thus lowering yields.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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ANFO_
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Please forgive my forum newbieness. I found a thread where this was discussed on the forum that didn't turn up through the forum search engine the
first time I looked?
Can a mod please dispose of this useless creation of mine
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