guy
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Acetone and ammonia?
I added some ammonia to acetone to try propan-2-imine. What I got was to separate layers; the bottom one is cloudy white. Did I make it?
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12AX7
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I'm betting that 1. your reaction doesn't work for any laundry list of reasons, and 2. the basic pH caused the acetone to polymerize.
The reaction seems plausible, but then you also need to reduce the C=O to C=N, and though the 2H freed from the NH3 technically count as reducing,
they are bonded to the N pretty well too. It seems to me this reaction needs a freaky catalyst and, at the very least, some heat.
...Someone tell me if this is BS or if the reaction actually works :rolleyes:
Tim
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guy
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The carbon is still the same oxidation number. The supposed mechanism is :NH3 attacks the C=O and forms NH2-C-OH and an the other H+ from NH2- or
something forms NH=C and H2O. I know this works for formaldehyde and eventually leads to hexamine.
"An imine can be synthesised by nucleophilic addition from a ketone or aldehyde and ammonia or an amine to a hemiaminal -C(OH)(NHR)- followed by
elimination of water to the imine." - Wikipedia
[Edited on 8/18/2006 by guy]
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jimmyboy
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from what i understand it will make diacetonamine and triacetonamine - a mixture of the two - couldnt find much info on those compounds
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Nicodem
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https://sciencemadness.org/talk/viewthread.php?tid=3960#pid4...
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guy
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Wow thats a cool compound, takes a month huh? Are there any catalysts that mights speed this up? Maybe NaOH?
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not_important
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A strong base is likely to give aldol condensation reactions, diacetone alcohol, mesityl oxide, and MIBK can be made from acetone that way.
Does the product have a smell?
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guy
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To form 2,2,6,6-tetramethylpiperidin-4-one, you need to perform 2 aldol condensations and dehydrations (all with OH-) to form
2,6-dimethylhepta-2,5-dien-4-one, then react that with ammonia to form the product. So I would think it would be faster to maybe use NaOH to finish
the first two steps.
Are there any specific instructions for condensing acetone? Put NaOH in acetone and....?
[Edited on 8/18/2006 by guy]
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12AX7
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Of course the carbon has the same oxidation state, but oxygen is more electronegative than nitrogen, so there ought to be some give/take there.
If it does indeed work, then I guess the ammoniacal hydrogen IS enough 
Tim
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Nicodem
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| Quote: | Originally posted by guy
To form 2,2,6,6-tetramethylpiperidin-4-one, you need to perform 2 aldol condensations and dehydrations (all with OH-) to form
2,6-dimethylhepta-2,5-dien-4-one, then react that with ammonia to form the product. So I would think it would be faster to maybe use NaOH to finish
the first two steps.
Are there any specific instructions for condensing acetone? Put NaOH in acetone and....? |
You got the mechanism wrong. There is no way phorone could be an intermediate. How could it even form in weakly basic conditions in the presence of
water? And there is absolutely no need to call for its intermediacy.
The mechanism is probably the one that is the most obvious and going trough the pathway of the lowest activation energies. Thus the condensation is
between acetoneimine molecules. An electrophilic protonated acetoneimine attacks a non-protonated nucleophilic acetoneimine. This is repeated once
more on the other side followed by imine hydrolysis and you have H2N-CMe2-CH2-CO-CH2-CMe2-NH2 which readily cyclisizes when heated trough the usual
retro-Michael/Michael addition mechanism (eliminating NH3).
Edit: Actually, now that I think of it, it is more likely the cyclization occurs by the condensation of the H2N-CMe2-C(=NH)-CH3 intermediate with
acetone directly already at room temperature. Anyway, if you want to speed up the reaction just heat it up. At 50°C it should be over in 12 hours,
but you will need to use a well stoppered bottle or some other up to 2 bar pressure resistant vessel unless you want to choke on ammonia.
[Edited on 19-8-2006 by Nicodem]
…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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guy
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Is what you are describing the Mannich Reaction, at least part of it?
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Nicodem
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Formaly the Mannich reaction refers on the use of HCHO in the presence of dialkylamines to aminomethylate acidic C-H bonds (ketones, aldehydes and
phenols). So this is not a Mannich reaction though the mechanism is esentialy the same with the difference that it is more probable that the
considerably more nucleophilic acetoneimine is aminoalkylated instead of the less reactive acetone.
…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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guy
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OK so about 3 days ago I put 10% ammonia, acetone and (NH4)2SO4 together (no measurements). So far it has turned yellow. How do I know the reaction
is complete? What are the properties of triacetonamine?
And PS what is the formula of the red colored compound, looks interesting? Yellow is phorone right but what is red?
[Edited on 8/22/2006 by guy]
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