Sciencemadness Discussion Board

Preparation of Copper (I) oxide from copper?

khourygeo77 - 16-5-2017 at 02:54

Any idea how this can be done?

I have tried many ways but always end up with copper II oxide


Also, how can I transform the copper metal into a green copper in big quantities? (I could manage to transform only the surface of the copper (very small portion) which isnt practical at all

JJay - 16-5-2017 at 05:00

I've never done it, but I know that copper (ii) oxide is sometimes used as a mild oxidizer, resulting in the formation of copper (i) oxide as a side product. If you want copper (i) oxide, you could first dissolve copper in sulfuric acid and then do a reaction with Fehling's solution or Benedict's reagent and (for example) glucose.

I think green copper is typically copper sulfide and that typically only the surface is green, even on very large and century old copper pieces like the Statue of Liberty... there seems to be a lot of information on metalworking sites on turning copper green... it depends on what materials you have available.

nezza - 16-5-2017 at 05:59

Yup. Dissolve the copper to give a solution of copper (II) ions. Add tartrate and Alkali until you get a deep blue solution. This is Fehlings solution. Boil with a mild reducing agent like glucose. The red precipitate that forms is copper (I) oxide.

khourygeo77 - 16-5-2017 at 09:41

I see it is difficult to find a reducing agent

https://en.wikipedia.org/wiki/Reducing_agent#Common_reducing...

I could find none of these at home.

I'll be trying to make iron II acetate solution by dissolving iron in H2O2 + vinegar then adding it to a copper acetate II solution. Do you think it will work? Or should I neutralize it with an alkali like baking soda beforehand ?

JJay - 16-5-2017 at 10:09

You can probably find fructose at your local grocery store or lactose at your local pharmacy... table sugar is nonreducing, but honey contains a lot of reducing sugars.

I think you'll probably get iron (iii) acetate if you use hydrogen peroxide with acetic acid to dissolve iron.

Making pure iron (ii) acetate requires taking care to keep air from oxidizing the iron to iron (iii): http://www.ims.demokritos.gr/people/tbou/iron_acetate.html



[Edited on 16-5-2017 by JJay]

Magpie - 16-5-2017 at 10:20

Brauer (forum library) has some methods. I know I've made it because I have some in my cabinet. I will have to check my notebooks to see how I made it.

khourygeo77 - 16-5-2017 at 10:32

Quote: Originally posted by JJay  
You can probably find fructose at your local grocery store or lactose at your local pharmacy... table sugar is nonreducing, but honey contains a lot of reducing sugars.

I think you'll probably get iron (iii) acetate if you use hydrogen peroxide with acetic acid to dissolve iron.

Making pure iron (ii) acetate requires taking care to keep air from oxidizing the iron to iron (iii): http://www.ims.demokritos.gr/people/tbou/iron_acetate.html



[Edited on 16-5-2017 by JJay]


Do you think molasse will work instead of honey? I saw it contains reducing sugars

Interesting about the Iron II acetate, how do you think I can obtain the powder without exposing to air? This always happened to me only when the iron acetate solution was getting dried and not when it was in solution

JJay - 16-5-2017 at 10:37

I am pretty sure that around here, most molasses is mostly sucrose, but you can obtain molasses that is high in reducing sugars, that would probably work.

Oh and as far as obtaining the powder without exposing it to air... that usually requires special equipment, but with some creativity and ingenuity, you can improvise.

[Edited on 16-5-2017 by JJay]

Magpie - 16-5-2017 at 10:48

I checked my inventory and what I have is CuO. I know I have seen Cu2O (a red powder) most likely when doing the Fehling's test for reducing compounds like glucose or aldehydes.

I suppose you could use the Fehling's reagents to prepare Cu2O. Instructions for making the reagents are shown on p. 192 in Brewster (forum library).

khourygeo77 - 16-5-2017 at 11:17

Quote: Originally posted by JJay  
I am pretty sure that around here, most molasses is mostly sucrose, but you can obtain molasses that is high in reducing sugars, that would probably work.

Oh and as far as obtaining the powder without exposing it to air... that usually requires special equipment, but with some creativity and ingenuity, you can improvise.

[Edited on 16-5-2017 by JJay]


Distilling the solution would pretty much do the work? Especially if the vapor passage is a very small beaker, no?

And is it necessary to react the copper II with an alkali before adding the reducing agent? Cant I add the reducing agent immediately to the copper II ion?

JJay - 16-5-2017 at 11:28

I don't know... I think it would depend on what the reducing agent is.

Booze - 16-5-2017 at 13:15

Is it possible to make copper carbonate by dissolving copper in a hot solution of vinegar and hydrogen peroxide, then adding baking soda and filter it, and turn that to copper (i) oxide by then boil it down and heat it above 1200 degrees?

[Edited on 16-5-2017 by Booze]

Melgar - 16-5-2017 at 13:33

You want reducing sugar? Well, this sounds like a fun experiment if I ever saw one:

https://en.wikipedia.org/wiki/Inverted_sugar_syrup

Sucrose rotates light polarization to the right, but hydrolyze it with heat and a pinch of citric acid, and it'll form a mixture of glucose and fructose that rotates light polarization left. You can even use light polarization as an indicator of when the reaction is done.

ninhydric1 - 16-5-2017 at 14:44

You could attempt a single displacement reaction using copper metal and a tungsten, mercury, silver, gold, or platinum salt in an aqueous solution due to the reactivity series of the metals, then heat it up to decompose the resulting copper salt into an oxide. A silver or mercury(I) salt would be preferred. But this method isn't very cost-efficient.

According to the Wikipedia page for copper(I) oxide, you can use sulfur dioxide to reduce copper(II) solutions, but there isn't much information about that. This method, if works, could be a useful procedure for obtaining copper(I) solutions.

[Edited on 5-16-2017 by ninhydric1]

[Edited on 5-16-2017 by ninhydric1]

symboom - 16-5-2017 at 16:57

Electrolysis of copper and zinc produces a yellow precipitate copper as the anode and zinc as the cathode in a salt water solution produces a yellow vrown percipitate

MeshPL - 17-5-2017 at 20:51

Copper I oxide can be made from copper ii solutions just by addition of sulfite and maybe changing pH to more basic.

It is also produced when copper is oxidised anodicaly in NaCl solution, cathode may also be copper.

If you want to make "green copper" you can try percipitating copper carbonate by addoing carbonate/bicarbonate to copper ii solution, filtering the percipitate and finally drying it.

Interestingly, anodic oxidation of copper in NaOH solution produces black goop (CuO?) adhering to the anode which, after taking the anode out of a solution and exposed to air, produces a green crust on the anode (green copper?).

nezza - 18-5-2017 at 01:33

If you want a nice easy reducing sugar try honey - it is nearly pure fructose.

chemplayer... - 18-5-2017 at 21:47

Have a look: https://www.youtube.com/watch?v=aVD4fjs8Umk

You're almost certainly going to have to dissolve the copper to form a soluble (II) salt and then reduce it. We found that the best reducing agent was sodium bisulfite. Use something too powerful and the result is copper (I) oxide which is too fine to actually filter properly.

Oscilllator - 19-5-2017 at 19:15

If you are in america you can buy high frucose corn syrup very cheaply which is a reducing sugar I believe. If you aren't (like me) just grab a cup or so of normal table sugar, add a dash of HCl or other strong acid and then boil it for an hour or so. Costs virtually nothing and I can verify it works quite well. Alternatively I remember a thread on here a while back in which solutions of copper were reduced with ascorbic acid, which can be bought relatively cheaply online as vitamin C.

Amos - 19-5-2017 at 23:04

If you treat copper(II) sulfate solution with ascorbic acid, you will end up with a fine precipitate of powdered copper metal but also a yellow or green supernatant liquid; keep adding ascorbic acid until the supernatant is yellow. Adding sodium hydroxide solution to this produces a yellow precipitate of what is rumored to be hydrous copper(I) oxide; it can simply be dried in air to produce the reddish form we all know and love.