RogueRose - 14-4-2016 at 19:51
I'm wondering if there is a good method of making CuO with bare copper wire or magnet wire (varnish insulation). I looked at both oxides and it seems
that heating in the presence of O2 could produce either of the oxides.
Would heating the copper in a closed steel container and then pumping pure O2 into the container be a better method tan burning the copper in air? I
could heat the steel container with some sort of electric heating element or combustion is an option but I think it might get contaminated with
soot/carbon with combustion, IDK.
Would 35% H2O2 be useful in making the CuO? I know it can be used as an O2 generator, which is how I was planning on generating the O2.
Is there any way to separate one oxide from the other if both are made?
DraconicAcid - 14-4-2016 at 22:02
Best thing to do would be to dissolve the copper metal in acid (preferably hydrochloric) with some hydrogen peroxide, then precipitate it with hot
excess sodium hydroxide. A bit of excess hydrogen peroxide will make sure it forms copper(II) oxide and no copper(I) oxide.
MeshPL - 14-4-2016 at 23:36
I bet you can also try to dissolve copper in ammonia, but it's trickier, as you need to supply air to react with copper, and ammonia is voltaile and
has a funny smell. And is dangerous in larger doses. On the other hand ammonia is sometimes more availavble than acids. Copper oxides formed by
contact of copper with air are dissolved by ammonia to form tetraaminacopper (II) hydroxide , which upon evaporation an slight heating should yield
CuO. Although Copper (I) oxide dissolves in ammonia too, it's complexes should oxidise fairly easily to copper (II).
RogueRose - 15-4-2016 at 00:35
Thanks for the replies. The HCl + H2O2 sounds like the better method with what I have. I am a little curious about how the varnish insulation will
effect the acid or whether it will dissolve the varnish. Would heating the wire (baking in oven or something) help remove the varnish or at least
cause weak spots to be better penetrated?
What about heating the HCl + H2O2 mix to a moderate temp (100-140F??)?
phlogiston - 15-4-2016 at 00:54
When you add sodium hydroxide solution to precipitate copper hydroxide, you will obtain a very gelatinous precipitate.
If you then boil it for a few minutes, the precipitate will quickly convert into non-gelatinous CuO that readily settles on the bottom and be filtered
and washed.
[Edited on 15-4-2016 by phlogiston]
Mabus - 15-4-2016 at 08:39
The best method is via electrolysis. You'll need two copper plates, a power source and a saline solution. You'll end up with copper(II) hydroxide,
which you can heat it to 80-100 °C, which gives copper(II) oxide.
Here's a good video to make the Cu(OH)2: https://www.youtube.com/watch?v=32q4NVEeJuQ
MeshPL - 17-4-2016 at 05:41
I once attempted anodical oxidation of copper using another piece of copper as a cathode and table salt solution of unknown concentration, but unlike
what Mabus says, and shows in video, the resulting suspension was orange, not black, indidcating presence of Cu2O, not CuO. Maybe it is the kind of
electrolyte or voltage or electrode surface area or whatever, that influences the result?
DraconicAcid - 17-4-2016 at 10:49
If you make a mixture of copper oxides, just dissolve them in hydrochloric acid, add some hydrogen peroxide, and precipitate with hot sodium
hydroxide.