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Author: Subject: Methylamine hydrochloride reacting with copper
proxymethoxy
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[*] posted on 6-9-2015 at 08:54
Methylamine hydrochloride reacting with copper


I synthesised a batch ot methylamine hydrochloride and after recrystalization and chloroform wash I transfered the bulk of it to a vacuum chamber with a few NaOH pellets. I used a metalic spoon to collect the last bit of methylamine from the buchner and sometime later, not having cleaned my spoon, I noticed it had gone green where wet methylamine was deposited.

Could anyone give me an idea of the reaction taking place?
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PHILOU Zrealone
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[*] posted on 6-9-2015 at 09:24


CH3-NH2.HCl <==--> CH3-NH2 + HCl

Cu + moist air --> superficial CuO + Cu(OH)2 + CuCO3

CuO + 2 HCl --> CuCl2 + H2O
Cu(OH)2 + 2 HCl --> CuCl2 + 2 H2O
CuCO3 + 2 HCl --> CuCl2 + CO2(g) + H2O

CuCl2 + 4 CH3-NH2 --> Cu(CH3-NH2)4Cl2 (or CuCl2.4 CH3-NH2)
Tetramethylamino copper (II) chloride complex




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macckone
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[*] posted on 7-9-2015 at 08:18


Most lower amines attack copper.
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Rosco Bodine
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[*] posted on 9-9-2015 at 23:28


IIRC Methylamine does not complex copper
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macckone
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[*] posted on 10-9-2015 at 09:42


It may not complex but it does attack.
Other things that are known to attack copper with better documentation.

Hexamethlene diamine
Hexamine
Ammonia
Urea

I certainly can't find any references that say it resists methylamine.
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PHILOU Zrealone
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[*] posted on 10-9-2015 at 09:54


Quote: Originally posted by Rosco Bodine  
IIRC Methylamine does not complex copper

Why wouldn't it?
Ammonia, hydrazine (sometimes with decomposition), ethylenediamine do form complexes...methylamine is more basic than ammonia and as such its free doublet is more prone to complexate.

There are structural references for Tetrakis(methylamine)dibromocopper.

There are also references for CuCl2 methylamine and Cu(HCO2)2 methylamine complexes decomposition pressure and heat of decomposition.
methylamine complex CuCl2 and Cu(HCO2)2.jpg - 207kB




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macckone
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[*] posted on 10-9-2015 at 10:32


Personally I think it probably does complex.
Rosco has his doubts.
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Rosco Bodine
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[*] posted on 10-9-2015 at 14:46


Actually it was trimethylamine that I was thinking of does not form a complex with copper. So it could be that methylamine or dimethylamine does complex copper.
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[*] posted on 10-9-2015 at 16:17


I would be very surprised if methylamine did not attack copper, especially in the presence of methylammonium salts.



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[*] posted on 12-9-2015 at 09:02


Great input everyone, thanks! This forum seems to host some pretty smart folk ;)
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[*] posted on 12-9-2015 at 09:04


There are some amazingly smart and experienced people here.

There are Others as well.




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Rosco Bodine
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[*] posted on 26-11-2017 at 17:17


Here is a relevant paper describing some complexes of copper and methylamine

Attachment: Substances_Formed_by_the_Interaction_of.pdf (399kB)
This file has been downloaded 59 times
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[*] posted on 30-11-2017 at 17:47


Ummm. Why not chloroform plus copper?

If you have residual Chloroform in you product, given a little heat (or time?), chloroform and copper might react.
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LearnedAmateur
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[*] posted on 1-12-2017 at 09:40


But what would be the product of that reaction? I thought chloroform was fairly inert hence its usefulness as an organic solvent; it takes a bit of a budge to make copper react with most reagents that it can. Here you've got a base with an amphoteric material, so I would've thought that would be the observed reaction.

Edit: I can't find any information on whether dichlorocarbene (:CCl2, generated from CHCl3 and NaOH for those who don't know) reacts with copper metal by itself or with any other present reagent. Might be something to look into.

[Edited on 1-12-2017 by LearnedAmateur]




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[*] posted on 1-12-2017 at 19:05


I think NaOH will dissolve copper to make sodium cuprate, won't it? CuO is amphoteric IIRC.

[Edited on 2-12-2017 by clearly_not_atara]




[Edited on 04-20-1969 by clearly_not_atara]
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[*] posted on 1-12-2017 at 21:45


Quote: Originally posted by clearly_not_atara  
I think NaOH will dissolve copper to make sodium cuprate, won't it? CuO is amphoteric IIRC.

[Edited on 2-12-2017 by clearly_not_atara]
I'm pretty sure it won't attack copper metal.



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[*] posted on 3-12-2017 at 16:10


Um. Once for a lab class, we attempted to fractionally distill a chlorinated hydrocarbon (carbon tet.?) utilizing stainless steel "scrungy" column packing. Ran short on stainless steel, and attempted to substitute a copper plated material (steel?).

At "tet" distillation temperature....instant and dramatic corrosion.
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