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Author: Subject: nitroethane from distilling nitromethane?
spanner
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[*] posted on 4-9-2006 at 14:48
nitroethane from distilling nitromethane?


Hi guys havnt been on for a while been at uni studying, but i found out something very interesting for all those budding chemists taking the pepper road. As we all know the biggest hurtle with this synth is the aquasition of nitroethane, well as it turns out nitromethane is easy to come by as we all know but what we dont reallise is that in that one litre of nitomethane that we just found or bought is about a 4% impurity called nitroethane which can be easily distilled, nitromethane B.P 101-103, Nitroethane B.P 114, in some cases depending on the supplier even higher % can be found i know its not a lot but hay you dont need that much for the synth.

[Edited on 4-9-2006 by spanner]

EbC: Title & spelling.

[Edited on 5-10-2006 by chemoleo]
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jon
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[*] posted on 3-10-2006 at 15:28


nitroethane is also used as a stabilizer for chlorinated hydrocarbons perchloroethylene for example.
or trichloroethane (used for drycleaning and as a degreasser think brake cleaner) it's present in a concentration of about 2%, along with nitromethane and nitropropane, and other things like tert-butanol.
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[*] posted on 3-10-2006 at 17:13


Nitromethane is easy to come by?

Not after Oklahoma City!




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Chris The Great
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[*] posted on 3-10-2006 at 19:18


The major hurdle IMO is oxidation of piperic acid in decent yield, and extracting piperine from pepper, not a simple problem like nitroethane which can be made from sodium nitrite and sodium ethyl sulfuric acid.

That route certainly beats distilling it from expensive nitromethane when there is only 4% or so.
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[*] posted on 6-10-2006 at 23:49


i have an efficent extraction process my yeilds are quite good for the extraction of piperine from pepper as far as redox from piperic acid to piperanol im still working on that and distilling of nitoethane from nitromethane is easier than actually making it and one less step as far as manufacturing goes, plus nitromethaneis about 9 bucks a litre here so 40mls of nitroethane for 9 bucks cost less than making it when you work out how much time it takes to make it
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[*] posted on 7-10-2006 at 00:12


Quote:
The major hurdle IMO is oxidation of piperic acid in decent yield, and extracting piperine from pepper

oh, i don't know - i'm more or less a complete no-brainer regarding chemistry and i managed to extract lots of nice clear yellowish piperine shards from black pepper without any effort. Going to piperidine from there is also not much of a problem. Ok, from there on i don't know, but it seems to be much less of a problem then nitroethan.
Quote:
not a simple problem like nitroethane which can be made from sodium nitrite and sodium ethyl sulfuric acid.

Starting with sodium nitrit is practically impossible for j. doe if he does not want to extract it (2%) from nitrating salt :)
If that's possible anyhow.
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[*] posted on 7-10-2006 at 10:26


Here's the problem with nitroethane.

Look at the BP's of the two materials:

Nitromethane BP 100-103 °C

Nitroethane BP 114 °C

Everyone knows that to get a good separtation from simple distillation you need at least 40C, and preferably 50C differnce in BPs when your dealing with such small quantities.

If the boiling points were reversed, then this would be a viable method with a decent fractionating column, but since its the way they are, your going to have hell of a time seperating them via fractional distillation... I'd say you'd need a column with at minimum 30 plates of seperation, and quite possibly much more.

Plus, who's to guarantee that your actually going to get 4%?

The nitroethane probably isn't put there on purpose, if anything it is an impurity from their distillation.
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[*] posted on 8-10-2006 at 03:34


your right it isnt put there on purpose it is classified as an impurity in the nitromethane but it is still there and the impurity ranges from 2 to 4 %. As far as distillation of the nitromethane if you use a sand bath you are able to controll your heat a lot more accurately and boil of your nitomethane while leaving you nitroethane behind. This is how i have done it and it seems to work fine.

[Edited on 8-10-2006 by spanner]
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[*] posted on 8-10-2006 at 03:44


And what makes you believe that the residue was nitroethane? What was its b.p.?

Interestingly, if it really was nitroethane, it would turn the distillation theory on its head! You should immediately publish such results. The chemical engineers would go mad about it.
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[*] posted on 8-10-2006 at 08:54


I find spanner's assertions misted in a nebula of mystery, so I searched for more reliable sources of information.

Gas chromatographic determination of impurities in nitromethane (http://dx.doi.org/10.1007/BF02302714)

Summary Impurities in commercially available nitromethane have been determined by gas-liquid chromatography using six different column packings. Besides nitromethane, 1-nitropropane, 2-nitropropane, acetonitrile, methanol, small amounts of ethanol and acetaldehyde have been detected. The presence of formaldehyde, ethyl acetate and acetone is probable. Mixtures containing comparable amounts of the four nitroalkanes could be separated on all columns, but plots of logarithms of the retention times vs. carbon number or boiling points of the nitroalkanes or column temperatures were linear only in case of columns packed with Porapak R and Q.


CHEMINFO (http://intox.org/databank/documents/chemical/nitromet/cie511...)

Nitromethane is available in grades of purity of 95-99+%.(21) It may contain other nitroalkanes, such nitroethane and nitropropane, ketones, aldehydes, propionitrile and water as impurities. Nitromethane may be transported in 55 gallon drums. The drum head space must be filled with nitrogen to reduce the risk of adiabatic compression. Nitromethane can be transported in bulk when mixed with a variety of dilutants or desensitizers to make it less sensitive to shock. These desensitizers with the minimum content by weight are 1,2-butylene oxide (40%), cyclohexanone (25%), 1,4-dioxane (35%), methanol (45%), 1-nitropropane (48%), 2-nitropropane (47%) and 1,1,1-trichloroethane (50%).(16)


It should be clear that the 2-5% of contaminants found in nitromethane is a mixture of compounds, one of which may be nitroethane. By the time you can convince me that your residue is pure nitroethane, hell will already be frozen over. Save your breath and our time: if you need nitroethane, make it yourself. Anything more Sisyphean than distilling myristicine from the Oil of Nutmeg is generally considered as doomed to fail. On the other hand, it is not bad to break general consensus, but wait to publicize your findings until you can also present irrefutable evidence to support them.




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[*] posted on 8-10-2006 at 09:29


The listed contaminates are expected ones, given that one (industrial) method of production is the vapour phase nitration of propane, which produces a mixture of 1- and 2- nitropropane, nitroethane, and nitromethane, along with a bit of alcohols, ketones, aldehydes, carboxylic acids, and nitriles - just as listed in the post above. For many purposes a single fractionation gives acceptable purity, solvent and fuel grade uses are not very picky.
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[*] posted on 8-10-2006 at 09:58


I have serious doubts on the presence of nitroethane in nitromethane. Over here we can buy a product, called "fuel booster", and it says 99.9% nitromethane on the label. Its intended use is as a fuel additive for karts, small model vehicles etc.
This stuff is a totally colorless liquid with a fairly pleasant smell and quite soluble in water. On evaporation it does not leave any residue.
This high purity, as it is on the label I find really surprising for a non-lab chemical. Its price is appr. EUR 20 per liter.




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[*] posted on 8-10-2006 at 10:48


The bottle of nitromethane I have at home says it is 95%. Sigma also sells different purities, ranging from 90-99%.



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[*] posted on 8-10-2006 at 19:13


Hay guys thanks for the feed back, im new to this so dont jump on my head, im just trying to find ways of acquiring regeants. I have given a sample of what i have distilled off to a friend of mine who works for a petrolium company and he is going to get it tested for me so i will post the results of that test when it comes in. (No where in my posts did i say that the nitoethane recovered was pure which is why i plan on getting it tested to see what the actual perentages are) this is all simply part of a test to see where certain reagants can be aquired from over the counter this method may not be a viable for some but it may be for others.
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[*] posted on 8-10-2006 at 22:34


Quote:
Originally posted by woelen
I have serious doubts on the presence of nitroethane in nitromethane. Over here we can buy a product, called "fuel booster", and it says 99.9% nitromethane on the label. Its intended use is as a fuel additive for karts, small model vehicles etc.
This stuff is a totally colorless liquid with a fairly pleasant smell and quite soluble in water. On evaporation it does not leave any residue.
This high purity, as it is on the label I find really surprising for a non-lab chemical. Its price is appr. EUR 20 per liter.


Interesting. Must be from vapour phase nitration of methane. That became less popular than nitrating propane because methane needs about 100 C higher tempuratures which gives more corrosion problems and more waste of nitric. But nitrating methane only has oxidation products as byproducts, and they are easy to remove by distillation and washing with water small amounts of water.

My references say you can get about a 9% solution of nitromethane in water.
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[*] posted on 10-10-2006 at 13:34


Even if nitroethane could be distilled off as an impurity of nitromethane, i don't think it would be a quantitative way of acquiring this reagent, it should also be a little expensive ...
A collegue of mine was doing some research on another OTC product which contained approx 30-60% nitroethane.
I checked out the mixture of the product he told me and found it to contain the following components:

Ingredients Weight % BP°
ethyl formate 30 - 60 54
nitroethane 30 - 60 114
n-butanol 1-5 118
ethyl acetate 3-7 77
2-phenoxyethanol 3-7 247

Would fractional distillation be enough to efficiently separate this component since the closest boiling temp is 4°
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[*] posted on 10-10-2006 at 14:27


I don't think the n-butanol would matter that much as the imine formation and subsequent reduction occurs in an alocholic medicum if using sodium borohydride.
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