Sciencemadness Discussion Board

Al/Ga reduction of nitromethane

overunity33 - 25-10-2010 at 03:07

I'm interested in the possibility of reducing nitromethane to methylamine gas using a gallium/aluminium alloy. I have read that the max solubility of Ga in Al is 9% by weight, anything over that and it liquefies once the solution gets hot. The idea would be to melt aluminum in a ceramic crucible and then stir in gallium. Could a piece with the correct surface area simply be dropped into a container of ice cooled nitromethane? Would it be better to just treat the surface of aluminum with gallium/galistan or form an alloy? Does anyone have experience using this in reductions?

Methansaeuretier - 25-10-2010 at 03:36

Quote: Originally posted by overunity33  
I'm interested in the possibility of reducing nitromethane to methylamine gas using a gallium/aluminium alloy. I have read that the max solubility of Ga in Al is 9% by weight, anything over that and it liquefies once the solution gets hot. The idea would be to melt aluminum in a ceramic crucible and then stir in gallium. Could a piece with the correct surface area simply be dropped into a container of ice cooled nitromethane? Would it be better to just treat the surface of aluminum with gallium/galistan or form an alloy? Does anyone have experience using this in reductions?


That should work. But don't forget to add a excess of a proton donor (formic-, hydrochloric- or acetic acid) or it won't work. A solvent like IPA, EtOH etc. should be used to moderate the reaction (otherwise it may produce an runaway reaction). After reaction has finished add NaOH to basfiy and liberate the MeNH2.

Btw does Gallium dissolve in NaOH? If not, the Gallium could be easily recycled.

[Edited on 25-10-2010 by Methansaeuretier]

Ebao-lu - 25-10-2010 at 03:39

are the urotropine/HCl or hoffman rearrangement of acetamide routes not working?

Hexagon - 25-10-2010 at 03:44

Would gallium salts work like mercury ones do? Geting them of gallium aloy thermomerters would not be difficult.

Methansaeuretier - 25-10-2010 at 06:33

Quote: Originally posted by Hexagon  
Would gallium salts work like mercury ones do? Geting them of gallium aloy thermomerters would not be difficult.

Usual way is to melt the gallium together with aluminium.
http://www.youtube.com/watch?v=QekysnaBy1w
http://www.youtube.com/watch?v=xYk_nr4p_r4&feature=relat...
But galliumsalts should be als reduced on Aluminium-Foil, but not as good as Mercury.

Mercury +0,796 V
Gallium -0,529 V
Aluminium -1,662 V

Try it!
Quote: Originally posted by Ebao-lu  
are the urotropine/HCl or hoffman rearrangement of acetamide routes not working?

They need so much time... Nitromethane is cheap and reduction is fast. No byproducts like dimethylamine etc. are formed etc.

[Edited on 25-10-2010 by Methansaeuretier]

[Edited on 25-10-2010 by Methansaeuretier]

Nicodem - 25-10-2010 at 06:41

Quote: Originally posted by overunity33  
I have read that the max solubility of Ga in Al is 9% by weight, anything over that and it liquefies once the solution gets hot. The idea would be to melt aluminum in a ceramic crucible and then stir in gallium. Could a piece with the correct surface area simply be dropped into a container of ice cooled nitromethane?

I do not know why you want to make the Al-Ga alloy separately and this way, but you should be aware that the surface of Al-Ga alloy is not protected against oxidation and thus the probable result of throwing Ga in molten Al is a metal on fire and possibly injuries on your body.

Also, due to obvious reasons, adding Al-Ga to nitromethane alone can not give methylamine, but utmost an dangerously exothermic runaway reaction or quite possibly nothing.

overunity33 - 25-10-2010 at 20:36

:Ebao-lu

If your goal is methylamine freebase dissolved in cold methanol then some routes are just redundant.. This seems like an interesting way to provide a stream of pure methylamine gas..

:Nicodem

It was mentioned previously that this would work by someone who has worked with these reactions before. When he said nitromethane he may have ment an OTC solution of methanol and nitromethane. Correct me if Im wrong but I believe neither acid nor h2o are needed for the reaction? The alcohol in an OTC fuel mix would serve their purpose.

Methansaeuretier - 26-10-2010 at 01:21

Quote: Originally posted by overunity33  
:Ebao-lu

Correct me if Im wrong but I believe neither acid nor h2o are needed for the reaction? The alcohol in an OTC fuel mix would serve their purpose.


I think MeOH is a bad H-Donor

zed - 26-10-2010 at 16:40

http://www.sciencemadness.org/talk/viewthread.php?tid=14173#...

An interesting link on this subject already exists. Wherein, some preps of Gallium/Aluminum amalgams are described.

Of special interest, was the amalgamation of Aluminum, with the liquid at room temperature alloy, Gallinstan. Easy.

[Edited on 27-10-2010 by zed]

[Edited on 27-10-2010 by zed]