proxymethoxy
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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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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
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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macckone
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Most lower amines attack copper.
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Rosco Bodine
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IIRC Methylamine does not complex copper
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macckone
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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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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.
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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macckone
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Personally I think it probably does complex.
Rosco has his doubts.
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Rosco Bodine
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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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DraconicAcid
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I would be very surprised if methylamine did not attack copper, especially in the presence of methylammonium salts.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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proxymethoxy
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Great input everyone, thanks! This forum seems to host some pretty smart folk 
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aga
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There are some amazingly smart and experienced people here.
There are Others as well.
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Rosco Bodine
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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 319 times
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zed
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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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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]
In chemistry, sometimes the solution is the problem.
It’s been a while, but I’m not dead! Updated 7/1/2020. Shout out to Aga, we got along well.
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clearly_not_atara
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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]
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DraconicAcid
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I'm pretty sure it won't attack copper metal.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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zed
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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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