Sciencemadness Discussion Board

Reducing copper hydroxide

Housane - 29-1-2019 at 09:57

Hi all,

Just wondering if there is an alternative to asorbic acid to reduce copper hydroxide to Copper (I) oxide. Original idea was from thought emporiums video on the subject.

Thanks

Housane

[Edited on 29-1-2019 by Housane]

AJKOER - 29-1-2019 at 12:42

See for example US Patent 1964569A.

General chemistry:

Cu(ll) + Cu = 2 Cu(l)

In the case of starting with Cu(OH)2, add aqueous ammonia to dissolve. Then add metal copper and heat releasing ammonia gas (perform outdoors, fumehood,...) and upon evaporation Cu2O.

Avoid contact with CO2 and air especially at acidic pH.

Housane - 29-1-2019 at 14:16

Ok so that is an option. Where could I buy asorbic acid cheaply if I wanted to use it?

stamasd - 30-1-2019 at 03:39

Another option is to use dextrose, or any substance with an aldehyde group. Cu2+ oxidizes the aldehyde groups to -COOH and gets reduced to Cu+. It's the working principle of Fehling's solution. Cu(OH)2 gets solubilized with sodium potassium tartrate (Rochelle salt) in an alkaline environment, then teacted with a dextrose solution while hot and Cu2O precipitates.

oberkarteufel - 30-1-2019 at 05:10

I second what stamasd wrote. And IIRC, glycerine can be used in place of Rochelle salt.
Glucose and ascorbic acid can be purchased with a reasonable price in shops with healthy food; the latter especially in the ones inclined to altmed.

Housane - 31-1-2019 at 00:18

So i have the Copper hydroxide and then mix with dextrose, glucose or asorbic acid an Cu(I)O will preciptate.

Right?

oberkarteufel - 31-1-2019 at 03:14

Wrong.
Did you do any actual research on your own? Because it's quite simple to check the reaction conditions using wikipedia and what was already written here.

https://en.wikipedia.org/wiki/Fehling%27s_solution
https://en.wikipedia.org/wiki/Benedict%27s_reagent

BTW, dextrose is the same thing as glucose.

P.S. Anyway, you were already given the direct instructions by stamasd
Quote: Originally posted by stamasd  
Cu(OH)2 gets solubilized with sodium potassium tartrate (Rochelle salt) /Or sodium citrate. OKT/ in an alkaline environment, then teacted with a dextrose solution while hot and Cu2O precipitates.
How did you manage to turn it into "mix and it's done"?

P.P.S. Sorry if this post feel too aggressive. Maybe I shouldn't write while with fever, hah.

[Edited on 31-1-2019 by oberkarteufel]

Housane - 31-1-2019 at 11:12

Ok sorry:o

In Thought emporiums video on this subject he uses asorbic acid, could this be substuted for glucose?

[Edited on 31-1-2019 by Housane]

Ubya - 31-1-2019 at 12:09

Quote: Originally posted by Housane  
Ok sorry:o

In Thought emporiums video on this subject he uses asorbic acid, could this be substuted for glucose?

[Edited on 31-1-2019 by Housane]


someone is not reading....
you can use glucose, BUT NOT ALONE, you need to do what stamasd said.

Housane - 31-1-2019 at 12:40

Sorry for not reading I get it now. I am only year 10.

Amos - 31-1-2019 at 21:31

Just curious here, what makes you want to use copper(II) hydroxide for this preparation? Do you have it already prepared? Is there an end result you have in mind for the copper(I) oxide you'd like to make?

Cu2O can be prepared more easily starting from copper(II) sulfate or the basic carbonate; these are the most common compounds of copper encountered in our hobby.

Housane - 1-2-2019 at 13:36

I just saw it on thought emporiums video and thought it was the only way. How would it be done with CuSO4?

Amos - 4-2-2019 at 10:30

You'll probably want to learn about this reagent/test. It can be scaled up to produce cuprous oxide on demand and uses only cheap, easy-to-obtain reagents.

https://en.wikipedia.org/wiki/Benedict%27s_reagent

Housane - 14-3-2019 at 00:07

I did the modified test as in thought empouriums video but used caustic soda instead of potassium hydroxide.
The product was some dark brown powder but when dried was mixed with some green crust.
Any ideas what this is and how to remove it?

Thanks

Jamie W

Ubya - 14-3-2019 at 03:26

Quote: Originally posted by Housane  
I did the modified test as in thought empouriums video but used caustic soda instead of potassium hydroxide.
The product was some dark brown powder but when dried was mixed with some green crust.
Any ideas what this is and how to remove it?

Thanks

Jamie W

Explain step by step what you did and what you used.
Dark brown powder could be copper metal, green crust could be any copper salt

XeonTheMGPony - 14-3-2019 at 04:16

Quote: Originally posted by Housane  
Ok so that is an option. Where could I buy asorbic acid cheaply if I wanted to use it?


Health food stores and brewing stores will have it in crystal form, there is all ways ebay too

Housane - 14-3-2019 at 06:23

OK so i mixed copper sulphate with the sodium hydroxide. to produce a blue/green solution. Then add ascorbic acid to a canary yellow. Let it sit, take off top water layer, filter and wash and do multiple washings. Last one with acetone then dry. as per video here https://www.youtube.com/watch?v=cLy8iVLvoRk

Nate - 14-3-2019 at 07:24

My bet is a mixture of the copper (I) oxide, and copper metal like (Ubya said). The green crust is (again like Ubya) said another copper salt.

Housane - 14-3-2019 at 09:26

Any Ideas How to fix it?

Nate - 14-3-2019 at 12:26

Fix what?

Housane - 14-3-2019 at 13:07

Sorry I was not clear. I was wondering how to purify the product to pure(er) Cu(I)O

MrHomeScientist - 15-3-2019 at 06:14

You may want to put this on the back burner for now and start fresh. Copper sulfate seems to be the easiest starting material, then create Fehling's solution or Benedict's reagent as described in the links above. If you still have some copper hydroxide, simply dissolve this in enough sulfuric acid to dissolve everything, to make copper sulfate.

Housane - 15-3-2019 at 12:51

Ok I will try again. Any idea what colour to aim for with copper hydroxide made from caustic soda when ascorbic acid is added

clearly_not_atara - 15-3-2019 at 13:21

FYI Rochelle salt can be made in situ by heating equimolar amounts of sodium bicarbonate and potassium bitartrate, commonly known as "baking soda" and "cream of tartar":

NaHCO3 + KH(CO2CHOH)2 >> KNa(CO2CHOH)2 + H2O + CO2 (g)