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Author: Subject: Nitromethane production
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[*] posted on 10-8-2023 at 03:47
Nitromethane production


I was thinking about an easy way to make nitromethane. What about reacting methanol with HCL to produce chloromethane and dissolve it into a solution of sodium nitrite ? Wont this reaction yield sodium chloride and nitromethane ?
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[*] posted on 10-8-2023 at 03:52


Quote: Originally posted by underground  
...What about reacting methanol with HCL to produce chloromethane...


Good luck.
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[*] posted on 10-8-2023 at 06:37


What unionised is likely alluding to is difficulty of working with chloromethane due to its low boiling point (-24C). Bromomethane is similarly challenging (bp = 4C) and both are alkylating agents that can be quite toxic. Iodomethane is (in my humble opinion) the only methyl halide even worth considering working with outside of a professional laboratory (bp = 42C). And even so, iodomethane is very toxic and volatile as well and an inhaling it is a very real possibility if one is not prepared adequately. Personally, I would never work with it outside of a fume hood, and I would advise anybody else to do the same.

Secondly, what you propose is easier said than done and does not really work in practice. Are you going to capture the alkyl halide produced and store it for a reaction later? The volatility and toxicity make this incredibly risky and challenging. Would you have it feed directly into NaNO2? Well, HCl fumes will likely travel into the NaNO2 solution as well and make nitrous acid. Also, NaNO2 is likely going to have some difficulty in certain organic solvents. Yet if you bubble CH3Cl into aqueous NaNO2 you'll inevitably convert some back into methanol. One would also certainly need proper ventilation, and ideally a scrubber for any CH3Cl that escapes.

Perhaps I'm wrong on either of these points. Perhaps the difficulties arise from other aspects. I have made nitroalkanes only a few times, and my experience with NaNO2 is primarily from working with diazonium salts. Just my two cents.

PS this topic has been discussed at length on the forum. If such an easy synthesis was feasible, I'm sure it would be discussed here.

[Edited on 10-8-2023 by SyntheticFunk]
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[*] posted on 10-8-2023 at 07:48


The idea is to directly react chloromethane with Nano2 solution. First pass the gass through water to dissolve any HCl then bubble it through NaNo2 solution. The solubility of chloromethane is relative low (5g/L) compare to HCL

[Edited on 10-8-2023 by underground]
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[*] posted on 10-8-2023 at 09:40


Quote: Originally posted by SyntheticFunk  
What unionised is likely alluding to is difficulty of working with chloromethane due to its low boiling point (-24C).

[Edited on 10-8-2023 by SyntheticFunk]

No.
I'm saying it simply does not work.


Either he's working with HCl as a gas which seems "unlikely" or he's talking about a solution of HCl in water.
And the problem there is that the reaction goes the other way.

Chloromethane hydrolyses in water.
The Wiki page glosses over the issues with the reaction.
If I recall correctly, the conditions are in the gas phase, hot and in teh presence of a catalyst.

Like I said, good luck.

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[*] posted on 10-8-2023 at 09:45


monochloroacetic acid + NaNO2 -> decarboxylation
https://www.orgsyn.org/demo.aspx?prep=CV1P0401
you can buy the acid from https://chemcraft.su/product/25266 or maybe synthesize by bubbling dry Cl2 gas into mixture of glacial acetic acid + sulfur https://www.youtube.com/watch?v=SpDtuK9BBBw
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[*] posted on 10-8-2023 at 09:59


If memory serves me well alkyl-halide + NaNO2 -> nitroalkane reaction requires DMSO as solvent. Even in DMSO the reaction is far from "perfect", yield is under 50% (maybe closer to 25%) with methyl-bromide or iodide (chloride was not even mentioned). The competing reaction is the formation of the alkyl-nitrite ester.

If you want to make nitromethane then Fery's suggestion is a tried and proven method.



[Edited on 10-8-2023 by Pumukli]
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[*] posted on 10-8-2023 at 12:01


Quote: Originally posted by unionised  

And the problem there is that the reaction goes the other way.


Agreed, however, as it boils at such a low temperature I imagined it could be continuously removed as it is produced, preventing the reverse reaction to drive it forward. However, I’m not familiar with the nuances of this specific synthesis. My apologies for incorrectly interpreting what you meant.
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