Sciencemadness Discussion Board

CuCl2 + Al in solvents other than water

Crypto - 23-12-2013 at 03:54

Aluminium reacts with an aqueous solution of CuCl2 to form hydrated AlCl3. What if copper chloride was dissolved in methanol or acetone. Would react in a similar manner?

[Edited on 23-12-2013 by Crypto]

TheChemiKid - 23-12-2013 at 03:58

This would still react, but the aluminum chloride formed would be less hydrated (If the copper chloride was anhydrous, the aluminum chloride would be anhydrous. If the copper chloride was hydrated, the aluminum chloride would be that hydrated.)

bismuthate - 23-12-2013 at 04:08

But the reaction of the to usualy involves water (thus the evolution of hydrogen) I believe. So wouldn't reacting the in an anhydrous enviorment change the reaction its self?

[Edited on 23-12-2013 by bismuthate]

TheChemiKid - 23-12-2013 at 04:26

I think the reaction would go as follows:
3CuCl2.2H2O + 2Al => AlCl3.6H2O + 2AlCl3 + 3Cu
AlCl3.6H2O + 2AlCl3 <=> 2AlCl3.3H2O

Or with anhydrous CuCl:
3CuCl2 + 2Al => 2AlCl3 + 3Cu

bismuthate - 23-12-2013 at 04:41

I dont actualy know how the reaction reaction proceeds but that couldn't be it because it doesn't evolve H2

Crypto - 23-12-2013 at 05:03

Does it really evolve hydrogen? That's a displacement reaction and water serves only as a solvent.

[Edited on 23-12-2013 by Crypto]

bismuthate - 23-12-2013 at 05:12

It does. It's more complex than it seems.

TheChemiKid - 23-12-2013 at 05:20

IIRC, Hydrogen is not evolved, only water.

bismuthate - 23-12-2013 at 05:23

Well the gas is flammable so I would think it's H2.

TheChemiKid - 23-12-2013 at 05:32

Are you sure the gas is flammable? If it is, I am intrigued.
I think that if hydrogen was produced, it would be by the reaction of aluminum and water. Maybe the high temperatures would get to the point when a sizable amount of hydrogen could actually be produced.

bismuthate - 23-12-2013 at 05:49

That was the conclusion I came to but then I wondered where the Al(OH)3 went. My theory is that it reacts with CuCl to form Cu(OH)2 which then decomposes to CuO. Although I've only seen a video of it being lit on fire (I can't seem to find it) so I'll need to test it myself.

TheChemiKid - 23-12-2013 at 05:55

Ok, I'll do the same when I am back from vacation.

bismuthate - 23-12-2013 at 06:01

well I just got back from the lab and the results are in. The bubbles formed by the reaction where flammable yet the vapors where not, thus leading me to believe that both H2 and H2O are formed. If my theory is correct I'd better make a new copper sample using Zn. Speaking of which when Zn reacts with CuSO4 does that release H2 because the reaction doesn't produce enough heat to boil water? If so I wonder how.

WGTR - 23-12-2013 at 07:21

I think you might be interested in this reference.

It should lead to a page 55 of The Chemical News and Journal of Physical Science, Volume 76.

Galinstan - 23-12-2013 at 08:16

The reaction is between the (CuCl4)2- which removes the aluminium oxide coating and a simple displacement reaction occurs, the hydrogen gas that is evolved is simply due to the aluminium reacting with the water forming aluminium hydroxide and hydrogen.

bismuthate - 23-12-2013 at 08:23

Tis what I concluded, but now I wonder why gas is evolved (I presume H2) in the reaction between CuSO4 and Zn?

TheChemiKid - 23-12-2013 at 08:39

I think zinc can also react with water at high temperatures to form zinc hydroxide and hydrogen.
I can't remember where I saw this, but I know that when zinc is hot enough, it will react with water. I think the reaction probably just reaches the temperature that can have the zinc react with water.

bismuthate - 23-12-2013 at 08:46

I don't believe that that is what's happening (the reaction doesn't get very not at all). Heres a better example; why is gass released when AgNO3 reacts with Cu?

Crypto - 23-12-2013 at 08:49
Quote:

The reaction is between the (CuCl4)2- which removes the aluminium oxide coating and a simple displacement reaction occurs, the hydrogen gas that is evolved is simply due to the aluminium reacting with the water forming aluminium hydroxide and hydrogen.



So would doing the reaction in methanol lead to the formation of aluminium methoxide? What about reacting it in acetone?

[Edited on 23-12-2013 by Crypto]

TheChemiKid - 23-12-2013 at 08:51

Hmm... Maybe, I don't know whether that would work. I don't know what will happen with acetone, I will check that out.
EDIT: Alkali, Alkaline-Earth, and some other reactive metals (Including Zinc) will react with acetone to form Pinacol Alcohols upon neutralization.

[Edited on 12-23-2013 by TheChemiKid]

WGTR - 23-12-2013 at 09:42

I've done some basic reductions with combinations of zinc and copper. The reactions are very interesting, and very old:

The Copper-Zinc Couple

TheChemiKid - 23-12-2013 at 09:55

Can you please give me some examples?

Random - 23-12-2013 at 09:56

This could actually mean that anhydrous CuCl2 in very small amount could remove protective layer of Al and make it react with anhydrous ethanol to produce Aluminum ethoxide.

TheChemiKid - 23-12-2013 at 10:02

How could this be separated from the aluminum chloride?

WGTR - 23-12-2013 at 11:02

Quote: Originally posted by TheChemiKid  
Can you please give me some examples?


Is the link in this post not working?

Crypto - 23-12-2013 at 11:09

This would actually be a pretty cool method of producing Al ethoxide or methoxide, but wouldn't it react with CuCl2 if more, than a small amount would be present?

Are there any other solvents in which copper chloride is soluble? I could only find info about methanol, ethanol and acetone.

[Edited on 23-12-2013 by Crypto]

DraconicAcid - 23-12-2013 at 12:29

Quote: Originally posted by bismuthate  
Tis what I concluded, but now I wonder why gas is evolved (I presume H2) in the reaction between CuSO4 and Zn?


Because copper salts are acidic.

Hydrated copper ions can lose H+ ions.

Cu(H2O)62+ + H2O -> Cu(H2O)5(OH)+ + H3O+.

The reaction of the zinc with the hydronium ion happens along with the reaction of the zinc with the copper ions.

Random - 23-12-2013 at 13:18

Quote: Originally posted by Crypto  
This would actually be a pretty cool method of producing Al ethoxide or methoxide, but wouldn't it react with CuCl2 if more, than a small amount would be present?

Are there any other solvents in which copper chloride is soluble? I could only find info about methanol, ethanol and acetone.

[Edited on 23-12-2013 by Crypto]


CuCl2 would be preferably anhydrous along with anhydrous alcohol and only a small amount would be used to remove protective layer of Al oxide. Al will react with anhydrous alcohol after that like any very reactive metal.

Crypto - 23-12-2013 at 15:26
Quote:

CuCl2 would be preferably anhydrous along with anhydrous alcohol and only a small amount would be used to remove protective layer of Al oxide. Al will react with anhydrous alcohol after that like any very reactive metal.


I understand, but what if one would add more CuCl2 ? Would it react with the ethoxide?

DraconicAcid - 23-12-2013 at 15:27

Aluminum will preferentially react with copper(II) ions over alcohol, surely.

Crypto - 23-12-2013 at 15:36
Quote:

Aluminum will preferentially react with copper(II) ions over alcohol, surely.


Forming anhydrous AlCl3 ? That would be an easy way to obtain it. No need for high temperatures and HCl or Cl gas...

I'll definitely do some experimenting when I'll get back from holidays :cool:

DraconicAcid - 23-12-2013 at 15:42

Quote: Originally posted by Crypto  

Quote:

Aluminum will preferentially react with copper(II) ions over alcohol, surely.


Forming anhydrous AlCl3 ? That would be an easy way to obtain it. No need for high temperatures and HCl or Cl gas...

I'll definitely do some experimenting when I'll get back from holidays :cool:


Your alcohol would have to be absolutely dry, and you would probably still get solvated AlCl3 rather than anhydrous. You might find that heating it to drive off the alcohol gives decomposition rather than nice anhydrous AlCl3.

Crypto - 23-12-2013 at 15:56

I was thinking about using methanol. My chem supply shop has 99.9% one. At least they state so ;) Not only dry but also has a pretty low boiling point so I want to give it a try. Of course I'm not arguing about getting anhydrous AlCl3 that way, because something tells me you're right.

I'll experiment anyway :)

macckone - 24-12-2013 at 01:17

Aluminum Chloride forms complexes with methanol, ethanol and acetone. If you are trying for a Friedel-Crafts catalyst, this won't work because of the complex.

It is possible that a small amount of CuCl2 would cause aluminum to react creating the methoxide or ethoxide but I don't have a reference. Mercuric Chloride definitely causes that to happen.

Crypto - 24-12-2013 at 02:27
Quote:

It is possible that a small amount of CuCl2 would cause aluminum to react creating the methoxide or ethoxide but I don't have a reference. Mercuric Chloride definitely causes that to happen.



Mercuric Chloride, Gallium and Iodine, all of them being expensive and kinda hard to get. Even thou only a small ammount is needed, CuCl2 would be a nice alternative if it works...

Does Al react with DCM?

Random - 24-12-2013 at 07:15

AlCl3 would probably be producing some ethyl chloride along the way, depends on the conditions in solution. Basic conditions among alkoxides wouldn't promote it as much as acidic conditions. CuCl2 is soluble like 53g/100mL alcohol thsts significant iirc. Maybe i'm wrong though.

macckone - 25-12-2013 at 15:16

Quote: Originally posted by Crypto  

Does Al react with DCM?


I am not sure what the reactivity would be but Al is generally incompatible with chlorinated compounds from a long term
perspective. I don't know that it would react under normal
conditions over a short period of time. With heat and abrasion
to remove the oxide coating it would likely react. Various
impurities in the aluminum and the DCM would change
the reactivity (water in particular). Any aluminum chloride
formed would likely accelerate the reaction.

WGTR - 25-12-2013 at 17:12

If there are aromatic hydrocarbons present in the DCM, then a pretty vigorous thermal runaway can occur in the presence of
aluminum or iron:

http://patentimages.storage.googleapis.com/pages/US3646229-0...

http://patentimages.storage.googleapis.com/pages/US3646229-1...

blogfast25 - 26-12-2013 at 07:31

Quote: Originally posted by macckone  
Quote: Originally posted by Crypto  

Does Al react with DCM?


I am not sure what the reactivity would be but Al is generally incompatible with chlorinated compounds from a long term
perspective.


There's a very long thread by 'peach' (on SM) on an attempt to chlorinate Al with dry HCl using dichloromethane (DCM) as a solvent (all done at RT). In my opinion the experiment failed but it did show that DCM shows no significant reactivity towards DCM.

I see the quest for anh. AlCl3 continues, as usual w/o much success.

There's a lab preparation that involves a dichloroalkane, iodine and Al powder (IIRW). I'll see if I can dig it up.

Edit:

Here the link to the Al/DCM/HCl thread:

http://www.sciencemadness.org/talk/viewthread.php?tid=14111&...

The post by ‘rrks’ on 26-7-2010 links to a *pdf which still works. Basically the reaction advocated is:

Al + 3/2 I2 + 3 CH2Cl2 === > AlCl3 + 3 CH2ICl

In strictly anhydrous conditions this yields anh. AlCl3, acc. to the author.

[Edited on 26-12-2013 by blogfast25]

blargish - 1-1-2014 at 13:29

Referring to one of the earlier points made...
Quote: Originally posted by bismuthate  
That was the conclusion I came to but then I wondered where the Al(OH)3 went. My theory is that it reacts with CuCl to form Cu(OH)2 which then decomposes to CuO. Although I've only seen a video of it being lit on fire (I can't seem to find it) so I'll need to test it myself.


I may be wrong (let me know if I am) but I believe the absence of Al(OH)3 may be due to the formation of tetrachloroaluminate as a side product in the reaction instead. First the Al2O3 layer on the Al is dissolved due to the presence of chloride ions (forming tetrachloroaluminate) via the following equation.

Al2O3 + 8Cl- + 3H2O --> 2AlCl4- + 6OH-

The freshly exposed Al reacts with water to form more aluminum oxide (and hydrogen gas)...

2Al + 3H2O --> Al2O3 + 3H2

Now what I think happens is that this process cycles along as a side reaction as the normal reaction between CuCl2 and Al is taking place

Hydroxoaluminate may be formed as well in a side reaction along with the tetrachloroaluminate as the solution becomes more basic. (I'm not too sure about this though)

Al2O3 + 3H2O + 2OH- --> 2Al(OH)4-

Both of these reactions could account for the absence of a precipitate of Al(OH)3 as I believe that both hydroxoaluminate and tetrachloroaluminate are soluble in water.

I have yet to test whether my assumptions are correct so this is hypothetical

Random - 1-1-2014 at 17:48

Quote: Originally posted by blargish  

Al2O3 + 8Cl- + 3H2O --> 2AlCl4- + 6OH-


something is missing because this doesn't occur in neutral conditions which in this equation probably are ( no H+ or OH- ion presence)

blogfast25 - 2-1-2014 at 06:18

Quote: Originally posted by blargish  
Al2O3 + 8Cl- + 3H2O --> 2AlCl4- + 6OH-



Nope. That doesn't happen to any appreciable degree.