Sciencemadness Discussion Board

making copper sulfate with ammonium sulfate?

symboom - 8-5-2011 at 04:41

copper hydroxide and ammonium sulfate forming Tetramminecopper(II) sulfate.then heating the mix to decomposition of the ammonia to form
copper (II) sulfate


[Edited on 8-5-2011 by symboom]

blogfast25 - 8-5-2011 at 04:50

It's ammonia (NH3), not ammonium (NH4+) that forms the Cu(NH3)4 (2+) complex. (NH4)2SO4 doesn't do anything in your scheme...

hkparker - 8-5-2011 at 09:50

Would the ammonium sulfate react with hydroxide to make ammonium hydroxide, which decomposes to ammonia and would complex the copper?

symboom - 8-5-2011 at 11:59

i guess i would have to add ammonium hydroxide to the solution to dissolve the copper hydroxide so both compounds are in solution. then heat to drive off ammonia from the two compounds [Cu(NH3)4(H2O)2]2+ (aq) + [2OH]− (+) [NH4]+ (+) [SO4]2- (heat)-->
copper sulfate + ammonia gas

[Edited on 8-5-2011 by symboom]

woelen - 8-5-2011 at 22:43

@hkparker: Indeed, the hydroxide will lead to formation of ammonia and subsequent formation of the cuprammine complex. But only part of the copper will coordinate to ammonia, there will not be enough ammonia to fully coordinate all copper (that would require 4 molecules of ammonia for each copper(II) ion).

@symboom: This method cannot be used to make pure copper sulfate. The cuprammine complex is quite stable and you won't be able to drive off all ammonia such that only copper remains in solution and no complex. The complex is so stable that it even is possible to isolate it in solid salts, e.g. one can make crystals of Cu(NH3)4SO4.H2O.

hkparker - 9-5-2011 at 15:50

Ah, overlooked that, sorry. Thanks woelen!

ScienceSquirrel - 9-5-2011 at 16:24

Copper sulphate is readily available everywhere as far as I know.
If you have to make it; the best and cheapest approach is 50% sulphuric acid, fine copper scrap eg electrical wire cores and air as an oxidant.
Set it up right and you should be able to make tens of grams per week.

symboom - 9-5-2011 at 16:52

i already have 5 pounds of copper sulfate i am trying to explore other ways to make copper sulfate.
what about electrolysis of ammonium sulfate. copper anode and graphite cathode and are separated by a salt bridge of ammonium sulfate.


[Edited on 10-5-2011 by symboom]

woelen - 10-5-2011 at 00:48

This latter idea may work, but it will be slow. The salt bridge will add a large internal resistance to the cell. The area around the cathode will become alkaline and hence ammonia will build up. You have to replace the cathode liquid and salt bridge a few times.

What you finally will end up with is a solution of ammonium copper sulfate, which can be crystallized out of the liquid.

symboom - 10-5-2011 at 04:53

Quote: Originally posted by woelen  
This latter idea may work, but it will be slow. The salt bridge will add a large internal resistance to the cell. The area around the cathode will become alkaline and hence ammonia will build up. You have to replace the cathode liquid and salt bridge a few times.

What you finally will end up with is a solution of ammonium copper sulfate, which can be crystallized out of the liquid.



--i think i have an idea what if i just separate anode from the cathode using a salt bridge and use the ammonium sulfate
to yield ammonium hydroxide:D and sulfuric acid:D

--The area around the cathode if i use an iron cathode will become alkaline and hence ammonia will build up. as you said the cathode will be a ammonium hydroxide solution? right?
and if i use platinum anode or lead for the anode the anode should have sulfuric acid.

--also when you say ammonium copper sulfate forms on which end anode cell or cathode cell

woelen - 10-5-2011 at 06:14

Making H2SO4 in this way will be a difficult thing again. How do you want to separate this from the ammonium sulfate? Don't expect too much of this from a practical point of view.

The copper ammonium sulfate solution will form at the anode side if the anode and cathode are separated by a salt bridge.

ScienceSquirrel - 11-5-2011 at 06:49

Making sulphuric acid by electrolysis is a fool's errand.
None of the chemistry you have suggested on this thread has a candle in hell's chance of working.
In some cases, even if it worked you are trying to turn expensive stuff in to cheap stuff.

symboom - 11-5-2011 at 07:54

Quote: Originally posted by woelen  
Making H2SO4 in this way will be a difficult thing again. How do you want to separate this from the ammonium sulfate? Don't expect too much of this from a practical point of view.

The copper ammonium sulfate solution will form at the anode side if the anode and cathode are separated by a salt bridge.


boil off the ammonium sulfate 455-536 °F (decomposes)
is what i was thinking 639 °F sulfuric acid boiling point.
to purify and end up with concentrated acid

but your right this is really impracticable.
btw ammonium sulfate is really cheap.
i just use my sulfuric acid i got through electrolysis of zinc sulfate which wasn't bad to get zinc and sulfuric acid because i needed some zinc anyways.my ideas yes they always seem out there.i like to try different ways to make the same thing. a lot of times i would rather make something then buy it just for the experience.and maybe to see if it works by experimenting a little.

woelen - 11-5-2011 at 12:52

It is good to regard your experiments as an educational or academic challenge and doing experiments to support your thought and building a better understanding is a very good thing. So, I encourage you to do experiments and see what happens. In this way you will also sometimes see unexpected things and strange results which provoke further thinking and further experimenting. But don't expect something which will give acceptable yields in practice.

My first experience in this was when I was 15 years old and tried to make CuCl2 by electrolyzing NaCl with copper electrodes. At the anode I obtained yellow/brown insoluble material instead of a clear blue solution and here the thinking, reading and gaining better understanding began :) I never made CuCl2 though in this way.

m1tanker78 - 11-5-2011 at 13:21

symboom, my simple experiments usually leave me with more questions than answers. It's frustrating but at the same time, rewarding because it forces me to branch out into other areas that I otherwise would have overlooked or never had an interest to begin with. When someone tells you, "It can't be done," they may or may not be right. They aren't saying, "It can't be tried." ;)

Tank

LanthanumK - 20-5-2011 at 15:17

Quote: Originally posted by woelen  
It is good to regard your experiments as an educational or academic challenge and doing experiments to support your thought and building a better understanding is a very good thing. So, I encourage you to do experiments and see what happens. In this way you will also sometimes see unexpected things and strange results which provoke further thinking and further experimenting. But don't expect something which will give acceptable yields in practice.

My first experience in this was when I was 15 years old and tried to make CuCl2 by electrolyzing NaCl with copper electrodes. At the anode I obtained yellow/brown insoluble material instead of a clear blue solution and here the thinking, reading and gaining better understanding began :) I never made CuCl2 though in this way.



I think that yellow/brown insoluble precipitate is microcrystalline copper(I) oxide.

@synboom I once completed a somewhat similar electrolysis process: I electrolyzed a solution of magnesium sulfate with carbon anode. Some magnesium hydroxide were produced at the cathode, which could be removed, reducing the pH of the solution to 2, which is very dilute sulfuric acid. Processes like this can be done but they are very ineffective.

[Edited on 21-5-2011 by LanthanumK]

The WiZard is In - 20-5-2011 at 16:07

Quote: Originally posted by m1tanker78  
symboom, my simple experiments usually leave me with more questions than answers. It's frustrating but at the same time, rewarding because it forces me to branch out into other areas that I otherwise would have overlooked or never had an interest to begin with. When someone tells you, "It can't be done," they may or may not be right. They aren't saying, "It can't be tried." ;)
Tank


Try this?

From Thorpe's Dictionary of Applied Chemistry 1912 edition.
I own three different eds, I first found this in my copy of
the 1939 ed. III:357 then checked Google.books. I used
Google for convenience.


An electrolytic process for the production of the sulphate consists
in using a solution of sodium sulphate and copper electrodes, a
current of carbon dioxide being passed through the liquid. Copper
is dissolved from the anode as sulphate, while sodium carbonate
is produced at the cathode. These react, regenerating sodium
sulphate and precipitating copper carbonate, which is collected and
dissolved in sulphuric acid (Kroupa, J. Soc. Chem. Ind. 1906, 78).

Google has the Kroupa ref. which saves me the trouble of scanning
my copy.

Copper Sulphate; Electrolytic Preparation of .
G. Kronpa. Oester. Z. Berg. u. Hiittenw., 1905, 53, 611, 627 ; Chem.-Zeit,, 1905, 29, Rep. 413.

Copper carbonate is produced by electrolysing a solution of sodium lulphato through which carbon dioxide is led between copper electrodes. At the anode copper is dissolved, whilst at the cathode widium carbonate is formed which acts on the copper sulphate and regenerates sodium sulphate. To prevent the hydrogen formed at the cathode from reducing the copper carbonate, the cathode is surrounded by a cotton fabric. The electrolyte must be constantly circulated and always kept acid with carbonic acid, as otherwise the anode becomes coated with a sticky yellow substance which increases the resistance. A current of 1 ampere per sq. dcm. is used, the voltage being 1.5 to 2 volts. As anode melted scrap copper or cement copper is used, the vats being made of tarred or paraffined wood. The carbonate formed is dissolved in sulphuric acid at 26o B. According to the author, the actual cost of the process for 100 kilos, of copper sulphate produced is 8-70 marks.—A. G. L.