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Esplosivo
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[*] posted on 10-2-2004 at 02:34
Nitromethane synthesis


Can nitromethane be produced by boiling methanol and Nitric acid under reflux? I am not sure but I think the reaction, if possible, would require a catalyst. What could it be?! It would interesting if this would work.

The reaction would be something like this:
CH3OH + HNO3 --> CH3NO3 + H2O

Seems like a common condensation reaction to me. I think it might work.

[Edited on 10-2-2004 by Esplosivo]

[Edited on 10-2-2004 by Esplosivo]
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AngelEyes
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[*] posted on 10-2-2004 at 02:57


CH<sub>3</sub>NO<sub>3</sub> is methyl nitrate...and I wouldn't fancy boiling that.

Nitromethane, as far as I can tell, is best made with a methyl halide and a nitrite...but you could probably find a lot more by doing a quick search.

I found nearly 20 procedures for synthesising nitroETHANE with a very quick search - I'm sure you could alter them to produce NitroMETHANE.

http://www.rhodium.ws/chemistry/nitroethane.html
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Esplosivo
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[*] posted on 10-2-2004 at 08:24


Thanks for the information.

Btw, would nitroethane have similar properties to nitromethane, or would it be more stable due to a longer side chain bonded to NO2.

There also doesn't seem to exist any MSDS data sheet on nitroethane - though I am getting a bit out of topic

[Edited on 10-2-2004 by Esplosivo]
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AngelEyes
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[*] posted on 10-2-2004 at 09:21


Hmmm... not sure. You're asking the wrong person as I have no experience with nitro-alkanes. I would suspect it probably is a little more stable but I can't be sure.
What do you want it for - RC fuel? Or are you trying sensitise another mixture?

Oh, and if you are going to search then do it properly. Here is a basic MSDS for nitroethane: http://physchem.ox.ac.uk/MSDS/NI/nitroethane.html

In fact, this is a really useful site with a vast amount of info, not just MSDS's: http://physchem.ox.ac.uk/MSDS/

[Edited on 10-2-2004 by AngelEyes]
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Esplosivo
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[*] posted on 10-2-2004 at 14:14


I would like to use it to sensitise explosives like Ammonium Nitrate. When I'll have the chance I'll try out some nitroethane and test it's properties. I am very busy lately ;)

I will try replacing some of the reactants to produce nitromethane too, as you suggested.

Where I live it won't be such a problem to get hold of the chemicals, much of which I've already got.
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DDTea
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[*] posted on 14-2-2004 at 16:21


Nitroethane is a bit more volatile than Nitromethane, and this is the reason to market it as a hobby fuel. Nitroethane has a flammability rating of 4 while Nitromethane, because of its slightly lower volatility, is 3. I remember reading a Nitromethane synthesis before, and it was a bit more complicated than what was stated, requiring Chloroacetic Acid, if I recall correctly.
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[*] posted on 14-2-2004 at 17:04


Right.
But I don´t think it is a good idea to make NM this way at home for such purposes because it would be rather expensive. And obtaining chloroacetic acid might be a greater problem than obtaining some NM.

Nevertheless here comes the receipe:

20g chloroacetic acid is solved in 40ml water and 12g Na2CO3 (anh.) is added. When the gas-production stopped the pH is checked it should be alkalic. The sln. is poured in a flask and a solution of 15g NaNO2 in 25ml water is added. The mixture is distilled over a small flame. Gas is produced and you get a heterogen destillate which is separated in a separatory funnel. The lower phase is dried over a small amount of CaCl2 and redestilled (collect the fraction at 100...102°C)
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AndersHoveland
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[*] posted on 29-11-2011 at 11:41


I had an idea to do a kolbe electrolysis on a solution of acetic acid while bubbling in nitrogen dioxide. As electric current is passed through acetic acid, the methyl radicals generated could potentially react with the dissolved NO2 to form nitromethane. The nitromethane would then hopefully be inert towards further reaction because the molecule does not ionize (or at least its ionization constant is negligable compared to acetic acid). The fact that nitromethane is also almost insoluble in water would also help, as most of it would separate out as it formed.

Quote:

A most important reaction in all these studies was found to be addition of methyl radicals to nitrogen dioxide to form nitromethane: CH3 + NO2 → CH3NO2

"The Reactions of Methyl and Acetyl Radicals with the Oxides of Nitrogen" Eric R. Allen, Kent W. Bagley

The article goes on to say, "It appears that if nitrosomethane is formed by the addition reaction: CH3 + NO → CH3NO, then it is mainly removed by reaction with excess nitric oxide or at appreciable nitrogen dioxide concentrations by the displacement reaction: CH3NO + NO2 → CH3NO2 + NO." I agree with the chemical equations, but the authors assumption is incorrect, the NO2 does not actually 'displace' the nitroso group, but rather NO2 is known to oxidize nitroso groups to nitro, while itself being reduced to nitric oxide.

[Edited on 29-11-2011 by AndersHoveland]
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[*] posted on 29-11-2011 at 12:55


Quote: Originally posted by Esplosivo  
Can nitromethane be produced by boiling methanol and Nitric acid under reflux? I am not sure but I think the reaction, if possible, would require a catalyst. What could it be?! It would interesting if this would work.

The reaction would be something like this:
CH3OH + HNO3 --> CH3NO3 + H2O

Seems like a common condensation reaction to me. I think it might work.

[Edited on 10-2-2004 by Esplosivo]

[Edited on 10-2-2004 by Esplosivo]


1. Nitromethane is as some have mentioned here much more easy available than e.g. nitroethane. Nitromethane is found in principally most part of so called "Nitro fuels" to radio-controlled vehicles.

2. The synthesis for nitromethane will not work with methanol and HNO3 refluxed. It can work vapor phase at high temperatures, from methanol - not from methane (works also). A more common route is from the alkane, such as propane.

Buy it instead of produce it.
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[*] posted on 29-11-2011 at 15:32


I suspect that bubbling methane into >70% conc. red fuming nitric acid (HNO3 + NO2) would yield some nitromethane (or the nitromethane might immediately get oxidized by the NO2 to trinitromethane). The only complication would be the potential for a Meyer reaction on the resulting nitromethane in the presence of such a low pH. But apparently this is not a problem because the literature makes frequent references to anhydrous nitric acid dissolved in nitromethane.

20% hydrochloric acid, or 30% sulfuric acid, can react with nitromethane to form hydroxylamine salts and formic acid. Typically the solution is heated for the reaction to proceed, though I am almost certain I read somewhere that there will be a reaction at room temperature, that heat is not absolutely required. But I might be wrong about this, as all the literature that can be found now seems to mention heating. But if it indeed is the case the heat is not required, it might be that the strong-acid induced hydrolysis of nitromethane requires free water, and that the water is not available in highly concentrated nitric acid.

[Edited on 29-11-2011 by AndersHoveland]
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UnintentionalChaos
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[*] posted on 29-11-2011 at 15:55


http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv1...

This procedure works. I have used it before. The chloroacetic acid isn't too easy to get though.




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AndersHoveland
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[*] posted on 29-11-2011 at 16:15


Quote: Originally posted by UnintentionalChaos  
http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv1...

This procedure works. I have used it before. The chloroacetic acid isn't too easy to get though.


To make chloroacetic acid there are two options: simply pass chlorine into glacial acetic acid (dissolved in chloroform) in the presence of sunlight for several hours [radical cascade mechanism], or bubble chlorine into a mix of acetic anhydride with some glacial acetic acid [reaction through tautomer CH2C(=O)OC(OH)=CH2].

Chloroacetic acid is very poisonous. It should not be confused with its other isomer, acetyl chloride.

[Edited on 30-11-2011 by AndersHoveland]
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[*] posted on 29-11-2011 at 18:18


Quote: Originally posted by AndersHoveland  
Quote: Originally posted by UnintentionalChaos  
http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv1...

This procedure works. I have used it before. The chloroacetic acid isn't too easy to get though.


To make chloroacetic acid there are two options: simply pass chlorine into glacial acetic acid (dissolved in chloroform) in the presence of sunlight for several hours [radical cascade mechanism], or bubble chlorine into a mix of acetic anhydride with some glacial acetic acid [reaction through tautomer CH2C(=O)OC(OH)=CH2].

Chloroacetic acid is very poisonous. It should not be confused with its other isomer, acetyl chloride.

[Edited on 30-11-2011 by AndersHoveland]


Not true. The Ac2O/GAA mix needs some pyridine to proceed effectively (see orgsyn prep of ethyl bromoacetate). This is a modified Hell-Volhard-Zelinsky reaction where the N-acetylpyridinium cation plays the role of acetyl chloride in the traditional HVZ reaction (where some red P is added to generate PClx and thus AcCl in situ).

Another viable modification has been posted on this forum before, where TCCA is used as the source of electrophilic chlorine. This avoids working with unpleasant and difficult to measure gaseous chlorine. The paper can be found in the second post, here: http://www.sciencemadness.org/talk/viewthread.php?action=pri...




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[*] posted on 30-11-2011 at 08:01


Quote: Originally posted by AndersHoveland  
Quote: Originally posted by UnintentionalChaos  
http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv1...

This procedure works. I have used it before. The chloroacetic acid isn't too easy to get though.


To make chloroacetic acid there are two options: simply pass chlorine into glacial acetic acid (dissolved in chloroform) in the presence of sunlight for several hours [radical cascade mechanism], or bubble chlorine into a mix of acetic anhydride with some glacial acetic acid [reaction through tautomer CH2C(=O)OC(OH)=CH2].

Chloroacetic acid is very poisonous. It should not be confused with its other isomer, acetyl chloride.

[Edited on 30-11-2011 by AndersHoveland]


It is toxic but nothing to overeact aswell. The method posted uses the sodium salt of chloroacetic acid also, which is said to be safer to handle.
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[*] posted on 30-11-2011 at 10:53




I suppose nitromethane can be made from sodium methyl sulfate with sodium nitrite.
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[*] posted on 30-11-2011 at 14:58


Quote: Originally posted by DDTea  
Nitroethane is a bit more volatile than Nitromethane, and this is the reason to market it as a hobby fuel. Nitroethane has a flammability rating of 4 while Nitromethane, because of its slightly lower volatility, is 3. I remember reading a Nitromethane synthesis before, and it was a bit more complicated than what was stated, requiring Chloroacetic Acid, if I recall correctly.


NFPA doesn't rate the flammability of chemicals by it's volatility but rather by it's flash point.
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[*] posted on 30-11-2011 at 16:57


Cholacetic acid might also be produced by H2SO4 hydrolysis of trichlorethene.



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[*] posted on 14-7-2013 at 15:30


how about sodium nitrite and methanol with sulfuric acid at reflux ?

and what about trichloroethylene and water (with H2SO4) at reflux.? to get chloroacetic acid?




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[*] posted on 14-7-2013 at 15:48


Quote: Originally posted by neptunium  
how about sodium nitrite and methanol with sulfuric acid at reflux ?


It is very easy to form nitrite esters, much easier than forming nitrates. In fact, ethyl nitrite can be formed by simply reacting ethanol with sodium nitrite and slowly adding cold 20% hydrochloric acid.

Ethyl nitrite can be isomerized to nitroethane.
Quote:
Conversion of Ethyl Nitrite into Nitroethane.


The solution of the nitrite in paraffin oil was placed in a flask provided with an upright spiral condenser, which in turn was connected with a combustion tube about 90 cm. long, filled with asbestos-wool (in order to expose a large surface to the gaseous nitrites), and heated in an asbestos box provided with a thermometer. The gaseous nitrite was carried into the tube by means of a slow stream of dry carbon dioxide. The nitro-compound was collected in a U-tube immersed in cold water, and the escaping nitrite in absolute alcohol or methyl alcohol cooled in ice-water. Fifteen or 20 c.c. of the nitrite solution were used at a time. A 25 % solution is convenient, and a 50 per cent. solution loses nitrite very rapidly. As the gaseous nitrite remains only momentarily in contact with the heated asbestos, the yield of the nitro-compound is small, the greater portion of the nitrite escaping conversion. Within four or five hours the greater part of the dissolved nitrite passes through the heated tube. The oily nitro-compound was easily recognised by the formation of the sodium compound on the addition of alcoholic sodium hydroxide solution. The nitro-compound was also reduced to the corresponding amine, which was converted into the platinichloride.

The conversion commenced at 100°C, and was fairly rapid at 120-130°C, when oily drops began to collect in the empty U-tube. At the end of four to five hours about 1 c.c. of the liquid collected, which responded very readily to the alcoholic sodium hydroxide test. If the temperature is raised to about 135-150°C, acetaldehyde and acetic acid are produced along with the nitro-compound. At 150-180°C the acid is the main product of the decomposition. The formation of the aldehyde and the acid is readily explained by the fact, fact that at a higher temperature the nitrite dissociates into alcohol and nitrous acid, the latter decomposing into nitric acid, and the higher oxides of nitrogen which oxidise the alcohol to the aldehyde and the acid. The best yield of the nitro-compound is obtained at 120-130°C.

Effect of Water and Alcohol on the Reaction
The presence of moisture, which is always present in the rapidly dried nitrites, facilitates the conversion of the nitrite into the nitro-compound. In order to ascertain if the presence of larger quantities of moisture in the gaseous nitrites gives rise to a larger percentage of nitro-compounds, the nitrites were passed through a wash-bottle containing water before entering the heated tube. It was found that when surcharged with moisture the nitrite dissociated more rapidly, yielding larger quantities of alcohols, aldehydes and acids without any appreciable increase in the yield of the nitro-compound. It appears that in the presence of traces of moisture, two reactions proceed simultaneously, the conversion of the nitrite into nitro-compound and the dissociation of the nitrite; and with the increase in the proportion of water the latter reaction proceeds with greater rapidity.

In order to determine if a better yield is obtained when an alcoholic solution of the nitrite is heated in a sealed tube, 10 cc of the solution were sealed in a glass tube and heated over flame. During the act of sealing, the part of the tube containing the solution should be immersed in a freezing mixture, otherwise explosions take place. The yield, however, was not very satisfactory. When heated at 100°C for five to six hours the solution, after distilling off the unchanged nitrite, and alcohol, gave about 1 cc of liquid, which positively tested for a nitro-paraffin, and which boiled at 98-104°C. Because of the mixture with alcohol, the actual boiling point was lowered. If, however, the solution was heated to 150°C for twelve to fifteen hours, the tube was found to, contain acetic arid, formed by the oxidation of the alcohol by nitric acid and higher oxides of nitrogen produced from the decomposition of the nitrite, besides free nitrite. The proportion of the nitrocompound was very small.


[Edited on 14-7-2013 by AndersHoveland]




I'm not saying let's go kill all the stupid people...I'm just saying lets remove all the warning labels and let the problem sort itself out.
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[*] posted on 14-7-2013 at 16:02


seems like a very long laborious complicated and low yield procedure...



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AndersHoveland
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[*] posted on 14-7-2013 at 17:28


Quote: Originally posted by AngelEyes  

Nitromethane, as far as I can tell, is best made with a methyl halide and a nitrite...

This is a little speculative, but...

Ethyl hypochlorite can be formed by passing chlorine into a solution of water, ethyl alcohol, a limited quantity of sodium hydroxide. Methyl hypochlorite is a dangerously sensitive explosive. (Journal of the Chemical Society, Volume 50, p607 )

Ethyl hypochlorite reacts with sulfur dioxide to form ethyl chlorosulfonate, CH3-CH2-O-SO2Cl
(warning: as an alkylating agent, this compound could be toxic, use caution)

We all know that diethyl sulfate can be reacted with various nucleophiles to displace the sulfate group. It even reacts with sodium perchlorate to form the ethyl perchlorate ester. (though the reaction is not advised, diethyl sulfate being extremely toxic/deadly, and ethyl perchlorate being a dangerous very sensitive explosive). Likely ethyl chlorosulfonate would react similarly as well.

C2H5SO3Cl + NaNO2 --> C2H5NO2 + NaSO3Cl

I admit it probably would not be a very practical route for preparing nitromethane, but it might potentially be useful for other things.

[Edited on 15-7-2013 by AndersHoveland]




I'm not saying let's go kill all the stupid people...I'm just saying lets remove all the warning labels and let the problem sort itself out.
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