Melgar - 17-4-2011 at 07:09
Ethylamine can be prepared from acetonitrile by the action of activated aluminum or sodium or probably any number of highly reactive metals. Since it
boils at 16C, it can then be passed as a gas into a solution of potassium persulfate. Potassium persulfate forms an acidic solution, so this should
trap the ethylamine, and oxidize it to the nitroso. Then, this mixture could be mixed with acetone and put in a pressure vessel and heated for some
time. The acetone would be gradually converted to dimethyldioxirane, which could oxidize the ethylamine to nitroethane. NaHCO3 would be used to keep
the Nef reaction from happening. This seems plausible enough. So can it work?
organometallic - 17-4-2011 at 10:40
myself, I would just appreciate a ref for the ethylamine to nitroethane conversion, as i possess some 70% ethylamine in water w/w solution, and would
rather it were the nitroethane.
ScienceSquirrel - 17-4-2011 at 10:42
It would be easier and cheaper to convert ethanol in to ethyl bromide or ethyl hydrogen sulphate and react that with sodium nitrite to form
nitrethane.
The reactants are easier to come by and the chemistry is well documented.
[Edited on 17-4-2011 by ScienceSquirrel]
Melgar - 17-4-2011 at 17:46
http://books.google.com/books?id=s76Dd3brvLMC&lpg=PA737&...
Potassium persulfate is a common pool chemical, and ethylamine can be prepared a whole bunch of ways. And the best synthesis for one person isn't
always the best synthesis for someone else. For example, I have a liter of acetonitrile I don't know what to do with, but no state for hundreds of
miles around me sells everclear.
After reading some literature I'm not sure if Al/Ga alloy would reduce nitriles, but Raney nickel could for sure, so I could always fall back on that.
Hexagon - 18-4-2011 at 00:41
The reduction ain't going to be a walk trough the park, and you are going to need a shitload of persulfate, and a shitload of acetone too, from witch
you are going to have to distill your nitroethane. Cant you distill ethanol from cheapo listerine? Or from cheap wine?
ScienceSquirrel - 18-4-2011 at 07:43
Finding a good starting material and a working method is half the battle in organic synthesis.
The industrial method is reacting nitric acid with propane at 350-400C but that is out of the range of most home chemists.
Melgar - 18-4-2011 at 10:21
Actually, I used to have a still for making 90% ethanol for drinking, until my friendly neighborhood policeman informed me that this was illegal and
promptly confiscated my still and set it up in his basement. But I found a liter of the tails from that stuff (tastes like crap but is still more
than 50% alcohol) and started slowly distilling it.
It smells kind of funny, but i'm sure that's just due to some minor, very smelly contaminants. The temperature at the top of the column hasn't
changed in two hours.
AndersHoveland - 18-4-2011 at 13:07
Oxidation of analine to nitrobenzene is well known.
"Peroxytrifluoroacetic Acid. II. The Oxidation of Anilines to Nitrobenzenes"
D. Emmons. J. Am. Chem. Soc., 1954, 76 (13), pp 3470–3472
(there are several other regents/catalysts that can generally substitute for Peroxytrifluoroacetic Acid, which are much more readily available to the
home chemist)
However, oxidation on ethylamine is probably not as straightforward. Nitroalkanes (such as nitroethane) are much more vulnerable to oxidation than
nitrobenzene. For example, nitromethane is oxidized by sodium hypochlorite to form chloropicrin. (U.S. Patent 3,106,588 October 8,1963)
However, there are also references to N2O5 actually being dissolved in nitromethane, which generally seem to be done at below 0°C, and I am not sure
for how long such mixtures are stable.
Nitroalkanes seem to be much more reactive under alkaline conditions, although when heated with mildly concentrated acids, nitroalkanes undergo the
Meyer reaction. Nitroethane on heating with hydrochloric acid yields hydroxylamine and acetic acid.
CH3CH2NO2 + H2O --> CH2CO2H + NH2OH
Victor Meyer, Ann. 1876, 180, p163
Trying to make nitroethane from ethylamine is probably not the best route. There exist several other much better described processes for preparing
nitroethane.
[Edited on 18-4-2011 by AndersHoveland]
Melgar - 18-4-2011 at 15:43
If you have an ozone generator, I read that ozone will oxidize a primary amine to a nitro compound. And the oxidizer you use definitely is important.
ie, using bleach for strecker degradation doesn't work so well because of all the chloramines produced. I guess the same is true here.
AndersHoveland - 19-4-2011 at 12:53
“The primary and secondary nitroalkanes exist in tautomeric equilibrium with an ‘aci’ or nitronic acid form. RCH2NO2 RCHNO2H (aci form)
Many of the reactions involving a nitroalkane will proceed through the ‘aci’ structure. Nitroalkanes react slowly with strong bases to form the
nitronate salt. Nitromethane reaction with strong bases (sodium hydroxide) proceeds rapidly to form the sodium salt of methazonic acid,
(2) CH3NO2 + NaOH HON=CHCH=NO2Na + (2) H2O
The dry sodium methaonate salt is highly shock-sensitive and can explode violently.
Another hazardous material, mercury fulminate, is formed from the reaction of the sodium salt of nitromethane with mercuric chloride.
While nitroparafins (such as nitroethane) are resistant to oxidation, they are easily reduced to the corresponding amine.”
“Industrial Solvents Handbook” Nicholas P. Cheremisinoff, Wesley L. Archer