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International Hazard
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Isopropylamine one pot synthesis
I want to synthesize isopropylamine because I read that it has very strong smell of fishes. I would like to see if smell is really that bad so I am
thinking about synthesizing it.
I read it I need isopropanol, nh3 gas and copper catalyst on wikipedia.
What I have and what I would do is:
Add ammonium nitrate to MEK/isopropanol nail polish remover and then add some copper acetate. After that I would add calcium hydroxide to that mixture
to make nh3 gas (NH4NO3 + Ca(OH)2) that would dissolve in that solution as soon as it's formed.
Would this produce some isopropylamine so I could smell it?
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vulture
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Isopropylamine definitely smells of fish. It's often the cause of the following conversation in the lab:
- Sonogashira again?
- Yep. Smelled it?
- Yep.
Minute traces will do. Don't sniff it when pure!
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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bbartlog
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The wikipedia article has at least the advantage that it provides a reference for the use of copper as a catalyst, namely, US patent 4014933.
If you read this, you will notice that wikipedia is sort of in error: the patent mentions a copper/cobalt/nickel catalyst.
Even if we assume that plain copper would work, there seems to be a further problem in that high pressure is involved.
You in turn have made a further, entirely unjustified leap by assuming that copper acetate will work as a catalyst in lieu of elemental copper.
And even if all of the above could somehow be swept aside, the soup you are proposing to create would probably still not do what you want. To begin
with, it's probably better to produce the NH3 in a separate container and pipe it in to the isopropyl alcohol [IPA]. This way you don't need to worry
about what calcium nitrate, ammonium nitrate, and residual water would do to your reagents. Second, MEK is probably more reactive than isopropyl
alcohol, speaking in very general terms; I'm thinking some side reaction would happen to it before the IPA would be touched.
The last time you proposed something like this, you were given the sensible advice that you should at least distill the nail polish remover before
trying to use it as a reagent. Why are you again proposing to use it, unaltered, here? I don't mean to seem condescending if your facilities are
really so limited that even distillation is impossible, but you will simply not be able to do some things (actually quite a lot of things, synthesis
wise) if all you are able to do is mix reagents in a vessel.
Finally, isopropylamine has been covered on this board before. See http://www.sciencemadness.org/talk/viewthread.php?action=pri...
Consensus seems to be that reductive amination of acetone is a nice OTC prep (though of course with your starting materials this would give
sec-butylamine).
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spirocycle
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cant you make it to a home depot or something the buy some acetone?
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Random
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vulture, thanks for notifying me about smelling, though I am not putting the nose into the bottle if I can smell it just by being around
bbartlog, MEK boils around 79 degrees and isopropanol around 82 degrees. Wouldn't that be hard to separate by distillation? Can I use some salting out
method or something to destroy ketone?
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Famousroger
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Use 2-bromopropane and ammonia, the imine and enamine form VERY slowly, and without pressure (200+ psi; ideally 800+), Calcium Fluoride/copper oxide
co-precipitated catalyst and high pressure hydrogen application following imine and enamine formation, yield will be essentially nil. Using the above
general method with higher-than-atmospheric pressure (~30psi +/- 5) yielded <1mL diisopropylamine, 6mL isopropylamine, and 212-ish mL unreacted
acetone. I did get to distill a 6mL fraction though, thinking, foolishly that this indicated subsequent formation of Di-substituted product;
underestimated the steric hinderance of isopropyl group...and slow slow imine and enamine formation; waiting 12 hrs...not enough at low pressure with
the mechanism IMO....albeit, I did not use the calcium fluoride/copper oxide coprecipitated catalyst mentioned in a patent i came across...
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Famousroger
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Update on this topic; I had nice success using isopropyl alcohol, sodium bromide, sulfuric acid, water and ammonia gas. Essentially the formation of
isopropyl bromide is step one followed by introduction of ammonia to the refluxing 2-bromopropane. This was accomplished through saturation at near
0*C of ammonium in water added to a round bottom. From the ammonia water round bottom a hose was led into a claisen 2-to-1 adapter which was
subsequently fitted to a distillation flask containing sodium bromide, isopropanol and water. To the straight vertical neck of the claisen adapter is
an additions funnel containing the sulfuric acid. Above that, a vigreux, side-arm condensor, receiving flask. The adapter into the receiving flask
has a hose running out from the vacuum nipple into cold water to regenerate the ammonia water. The ammonia gas is generated by heating the cold water
with ammonia (solubility of ammonia(g) is decreased as temp increases). This ensemble increased contact time in the gas phase between ammonia gas and
2-bromopropane. The result was a mixture of product including a small amount of isopropanol, diisopropyl ether, water, and a liquid which boiled
strictly at 84*C. I am still in progress with this process, so I am not going to post any numbers yet. Have video and photos, but those also will
come later. Was expecting much, much more isopropylamine, which seems to be a very modest portion of the product.
Thanks
fRS
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Famousroger
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(diisopropylamine was substantially favored versus isopropylamine, my last sentence may have been ambiguous)
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Famousroger
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Subsequently, diethylsufate was produced by taking the sodium sulfate produced in the reaction of sodium bromide, sulfuric acid and isopropanol - in
fact, the same flask was used. After cooling to below <or= 30*C, sodium sulfate crystals formed. After holding the temperature around or below
for 10 minutes I was confident it was all frozen (the sodium sulfate was already largely frozen since being removed from heating some time before
this). I then decanted off any liquid in the flask. Following this, the bulk of the crystals were removed onto filter paper and squeezed to liberate
any remaining liquids, while the smaller pieces were allowed to remain in the flask. Acetone was added to the flask, while the larger crystals were
allowed to dry on fresh filter paper. The flask was swirled with acetone until virtually all crystal were off the walls of the flask and resting at
th bottom. The flask was then heated slowly up to the boiling point acetone while the larger crystals drying on filter paper began to be added. Once
all the sodium sulfate was again in the flask, heating was continued, boiling off all acetone and melting all sodium sulfate. Heating continued
further until the liquid sodium sulfate reached and held 110*C for 5 minutes. After this i felt confident the flask was free of excess water. I then
slowly added 75mL ~95% ethanol and 80 mL 96% sulfuric acid (ironically introducing trace h20, but c'est la vie). This mixture was heated slowly until
a couple drops of diethyl ether (boiling just above 35) reached the thermometer in the still. Th hat
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NEMO-Chemistry
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Isopropylamine
I cant find much on making this.
(CH3)2CHOH + NH3 → (CH3)2CHNH2 + H2O
What I found says to use a copper or nickle catalyst.
I was about to ask a question...But hold that thought! Before i get my spoon out, i found a clue i want to look at....
ok one question. is this amination reaction of a secondary alcohol? yes it is isnt it? Ok let me go research that first. I might not need to ask my
main question then, woohoo might be able to get by without spoon feeding on this!
brb
just for info...
The use is for Dille–Koppanyi reagent, i am looking at different tests for testing plant extract TLC plates.
[Edited on 11-10-2017 by NEMO-Chemistry]
Edit (zts): Merged threads and deleted old thread link
[Edited on 10-11-2017 by zts16]
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NEMO-Chemistry
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This sounded so easy!! I should have known better, however looks like magpie yet again has a reasonable solution .
http://www.sciencemadness.org/talk/viewthread.php?action=pri...
Will keep researching as i want to do this, but its dropping in the rankings of which experiments to do first, it did sound straight forward, but is
looking like it needs to come later.
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Texium
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Threads Merged
11-10-2017 at 09:39 |
NEMO-Chemistry
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Found this, looks to be useful. But is above my knowledge level at the moment, however lets see how far i can get with some reading .
i will post what i find in case it helps someone else.
Attachment: bhn2011.pdf (533kB)
This file has been downloaded 4337 times
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AJKOER
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Alternate one pot approach: UV photolysis of laughing gas N2O, propane C3H8, NH3 and H2O mixture (but, you may still only produce a related amine as
isopropyl is an isomer).
Logic is based on a reported related photolysis based on methane which does not have the benefical effect of N2O to create more hydroxyl radicals. See
K. Ogura, "Photolysis of CH4, NH3, H2O mixture: formation of methylamine and ethylenediamine", in Journal of Photochemistry and Photobiology A:
Chemistry, Volume 49, Issues 1–2, September 1989, Pages 53-61, https://doi.org/10.1016/1010-6030(89)87105-9, link: http://www.sciencedirect.com/science/article/pii/10106030898... . Here is the abstract:
"The photolysis of the mixture CH4, NH3, H2O was performed with a low pressure mercury lamp at 100 °C and atmospheric pressure. Of the products, the
major nitrogen-containing compounds were methylamine and ethylenediamine; the maximum selectivity of the two amines exceeded 99% in the mol per cent
of N-containing products. The other products were methanol, ethane and hydrogen, but the formation of methanol and ethane decreased rapidly with an
increase in the amount of added ammonia. This was attributed to the preferential reactivity of methyl radicals with NH2 rather than with OH and/or
CH3. The formation rates of NH2, CH3NH2 and NH2C2H4NH2 are discussed."
where the cited product CH3OH is a good source of hydroxyl radicals under photolysis, hence the recommended addition of N2O to the water/ammonia mix
as methanol is less of an expected product with C3H8 photolysis.
The photolysis of pure C3H8 apparently proceeds as follows:
C3H8 + UV → *C3H8
*C3H8 → C2H5 + .CH3 (see http://www.sciencedirect.com/science/article/pii/00472670738...)
and I am suggesting in the presence of NH3 and .OH (from N2O) the following:
N2O + H2O + UV = N2 + .OH + OH-
NH3 + .OH = .NH2 + H2O
C3H8 + .OH = .C3H7 + H2O
.C3H7 + .NH2 = C3H7NH2
.CH3 + .OH = CH3OH
.....
together with other products.
[Edit] Did find a related photolysis (see "Photolysis of ammonia at 2062 A. in the presence of propane", 1968, by W. E. Groth, et al, DOI:
10.1021/j100857a034), to quote the abstract:
"Ammonia was photolyzed at 2062 Å in the presence of propane as a hydrogen atom scavenger. The only photo process at this wavelength is shown to be
NH3 + hv-(2062 Å) → NH2(2B1) + H (a). H2, N2, N2H4, C3H6, C6H14, i-C3H7NH2, n-C3H7NH2, and small amounts of unidentified amines were produced in
the photolyses. All products were determined quantitatively as functions of absorbed irradiation dose. A reaction mechanism is developed on the basis
of the observed quantum yields. The ratio of disproportionation to addition reactions between amino and propyl radicals is obtained to be 0.21 ±
0.07."
Link: https://www.researchgate.net/publication/231421787_Photolysi...
In my version of the photolysis, I would expect less of :
C3H8 + .H = .C3H7 + H2
and more of:
C3H8 + .OH = .C3H7 + H2O
due to the removal of the hydrogen atom radical by:
.H + .OH = H2O
together with photolysis at a different wave length not promoting:
NH3 + UV = .NH2 + .H
[Edited on 12-10-2017 by AJKOER]
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NEMO-Chemistry
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Thx for all the great info!! Wow this is way above my ability at the moment, seeing as my end goal is simply to make a testing reagent, this can
wait!! Amazing how easy it looked on paper!
I am looking for different tests to identify plant alkaloids from TLC plates. So the need is not urgent.
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