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Eclectic
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Isopropylamine and Diisopropylamine from Acetone
Does anyone have actual lab prep or direct experience making these using zinc dust as the reductant, preferably in aqueous system using an ammonium
salt as the ammonia donor?
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Nicodem
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You could try using the method described in the Example 1 of FR971429 (reductive amination of cyclohexanone with NH3, using Zn + NiSO4), but having a
lower NH3 vs. ketone ratio instead to promote the formation of the secondary amine. You would still get a mixture of isopropylamine and
diisopropylamine, but these can be easily separated by distillation, and besides you say you want both.
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Eclectic
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Yes, both usefull ammonia like solvents at room temp
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madscientist
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You're likely aware of this, but aluminum amalgam does the trick. Dab a bit of HgCl2 on aluminum foil and drop it into the solution of acetone and
ammonia. Your house will smell like a dead whale.
I weep at the sight of flaming acetic anhydride.
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Anders2
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If I can make a suggestion, use NH2OH to form the oxime with acetone, then Zn/HCl. This should form the isopropylamine. As for Diisopropylamine,
perhaps by making isobromopropane from the alcohol (see the topic "Iodomethane"), then reacting the bromopropane with isopropylamine.
If iso chloro propane is used instead of the bromo, it would have to be refluxed (in a sealed apparatus, under a fumehood)
Alternatively Propylene, the product of conc. H2SO4 on isopropanol, could be heated with either ammonia gas or propylamine gas, but this would be more
difficult/dangerous.
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leu
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The easiest way for most members would be to form the oxime and reduce that to isopropylamine with amalgamated aluminum 
[Edited on 15-9-2010 by leu]
Chemistry is our Covalent Bond
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mario840
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so what Hydroxylamine and acetone form oxime ? we must heat it under reflux ? how long ? give some more useful information and then amalgamated
aluminum , and the product will be only isopropylamine with some besides product ? what yield ? is there patent for this ?
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Hexagon
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If you want monoisopropylamine, Roundup is the way to go, 3 or 4 euros per mole of iPrNH2 is too expensive?
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Eclectic
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Absolutely, compared to the cost of acetone and ammonia. 
And it's for solvent use, not reagent or synthesis feedstock.
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mario840
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so how to extract isopropylamine from roundup ? diethyl ether ? please tell me more about it
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Hexagon
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Havent done it, but roundup is a glifosate salt of isopropylamine (or ammonia, more rare) in aqueous solution, so add an excess of base (or titrate),
saturate with NaCl and then boil the isopropylamine, just like one does with ammonia, witch can be dried with NaOH for example and condensed to obtain
it pure or bubbled in what ever solvent you want. I think that from 1 liter of common roundup (4-6€ I think) one can obtain something like 1,5 moles
of isopropylamine.
@ Eclectic: What kind of aplication you want the isopropylamine for? The only one I can think of you cant substitute it for a more common and cheap
organic solvent is for some king of alkali metal solvating.
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Eclectic
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solvation and recrystalization of borohydrides. I have 100 kg LiH
How mad is that? Also 30 lbs Hg
I also want to make Hunig's base.
[Edited on 9-15-2010 by Eclectic]
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madscientist
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...that's a lot of LiH.
If you're going for Hunig's base the Al/Hg amalgam is your best bet - cheap and effective, and clearly someone also has no shortage of Hg.  Just use an excess of acetone and you'll be good to go.
I weep at the sight of flaming acetic anhydride.
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Anders2
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Acetone spontaneously condenses with a solution of hydroxylamine to form the oxime, no heating required. (CH3)2C=NOH
Ammonia forms very transient amines =NH, but the equilibrium is very small.
Hydrazine condenses to form hydrazones =N--N= in very basic conditions, and then this hydrolyzes back to acetone and hydrazine once the pH of the
solution goes back to normal. Hexagon, that roundup idea is good one.
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madscientist
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The *imine* (C=N-H) may not be stable but that's not an issue, as the reduction of imines to amines with Al/Hg proceeds smoothly, rapidly, and with
relatively high yields. It's cheap and it's simple and all the materials are readily available.
I weep at the sight of flaming acetic anhydride.
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Anders2
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A better method might be to use NaOH on solid Aluminum.
Not only will this eleminate the requirement for Hg, but also the basic conditions will help to favor the imine equilibrium.
Obviously the solution should not be too concentrated with the NaOH, otherwise the ammonia may start bubbling out, Cooling the solution may help.
[Edited on 16-9-2010 by Anders2]
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madscientist
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Do you have any references pertaining to NaOH/Al reduction of imines? To my knowledge it does not work - not everything that produces hydrogen will
result in a reduction. Be careful with speculation, it could lead others to waste valuable reagents or worse (accidents.)
I weep at the sight of flaming acetic anhydride.
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Hexagon
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In fact aq. sodium hydroxide works while activating aluminum on a microwave asisted pinacol coupling rxn, Don't know on a reduction like this...
The reference: http://nopr.niscair.res.in/bitstream/123456789/6173/1/IJCB%2045B(1)%20332-334.pdf
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madscientist
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Ah, yes, I was referring to imine reduction specifically. Thanks for sharing that reference though!
I weep at the sight of flaming acetic anhydride.
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Eclectic
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Ideal system would be water, acetone, ammonium chloride, and a dissolving reactive metal, with or without nickel..., scrap aluminum turnings would be
great if it works, but I have zinc dust. I was just asking if anyone has actually DONE it, or has actual prep procedure.
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mario840
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what about roundup ? there is 360SL 360 g salt per 1 liter for 5- 6 euro and I am really interesting about method isolation , we may add NaOH like
Hexagon said or Na2CO3 to ph 10 and then extract with IPA ? will it works ? or destill directly from reaction mixture ? what do you think ?
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Eclectic
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It's probably reasonable if you want a few hundred grams, I'm thinking more in terms of liters....
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mario840
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yes but i wonder if this "method" works , amine will form a layer on top (very low density) or what ? if form there will be easy to extract or
separate withouth heating , i'm just asking that's all 
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Anders2
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Here is a relevent link:
http://www.organic-chemistry.org/synthesis/N1H/reductionsimi...
As you can see, plain imines are not used, an organic amine is usually used to form the imine, which becomes more resistant to hydrolysis, because the
resulting condensate then lacks any N--H bonds, and becomes insoluble in the water that is produced.
Using just NH4OH, and doing reduction is likely to give very low yeilds, since the main reaction will be the reduction of free acetone (which
dominates in the equilibrium) to Isopropanol, or even further to propane! Since the regents for this are cheap, however, it might be worth
investigating, but a basic envirorment is definately required to get any workable equilibrium.
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madscientist
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That is not true - I performed a reductive amination on acetone in methanol/water 50/50 with Al/Hg amalgam and the yields were reasonable. This was 7
or 8 years ago so I can't throw out numbers but it does work and it works well.
A lack of a hydrogen bonded to the nitrogen is not going to pull it out of solution and cause this to somehow effect a reduction only in this case.
I weep at the sight of flaming acetic anhydride.
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