gurlen - 26-12-2004 at 13:39
one of my friend said me to produce Cu2O at home i have to heat Cu nearly 3 hours on a electricity heater
is it true or not.
JohnWW - 26-12-2004 at 13:45
It would have to be finely-divided to begin with, and with an adequate oxygen supply.
kclo4 - 26-12-2004 at 13:51
Do electrolysis with copper in salt-water wash the water and stuff away then you are left with cu2o
Theoretic - 27-12-2004 at 07:47
When you do that, you get Cu(OH)2. I've tried it.
gurlen - 27-12-2004 at 08:53
ok but i didnt understand wihich one is true if i elctrosis it in salt water will it be Cu2O or not and my Cu2O has to be stick. thank you every body
from turkish repulic
yok subcekt felan
zozu - 27-12-2004 at 09:13
First coppers surface gets black, you take away the black surface, then you have Cu2O in your hands. And Cu(OH)2 should be this black part mentioned
above.
And you must use not fire for this, u must use 1200 watt electric-oven
[Edited on 27-12-2004 by zozu]
[Edited on 27-12-2004 by zozu]
[Edited on 27-12-2004 by zozu]
Mumbles - 27-12-2004 at 16:42
in my experience heating Cu gave much more CuO than Cu2O. Maybe I was just heating a lot hotter than neccesary though. If you are really interested
in the compound you may want to look into a reduction of CuCl2 with Cu to form CuCl, and then adding the precipitate to boiling NaOH. This should
give you your desired compound.
guy - 28-12-2004 at 14:22
I made copper(I) oxide easily.
First do electrolysis of Cu electrodes in salt water w/ a salt bridge. You will get CuCl.
Then add sodium hydroxide, and a red copper like precipitate will occur.
(To know if its reall Cu2O, leave it in the air and it will turn black)
Polverone - 28-12-2004 at 16:46
IIRC, you can also dissolve CuSO4 in water, mix it with NaOH solution, and add some fructose (and warm) to reduce it to Cu2O. I may have added some
aqueous ammonia too before the fructose. In any case I recall doing this successfully after making a solution "like" Fehling's solution
and reducing it with fructose and ascorbic acid. However, others' experiments here have indicated that you can actually reduce copper compounds
all the way to copper metal with ascorbic acid, depending on conditions, so you might just want to use fructose.
chemoleo - 28-12-2004 at 17:54
Yes, I also think the method Polverone described is the easiest - although I don't know about stoichiometries.
Anyway, I think there is yet another method that hasn't been mentioned, which is to heat copper metal (excess) in a copper salt solution (or was
it hydroxide?). This reaction is supposed to be quantitative.
FrankRizzo - 29-12-2004 at 18:50
You can also mix CuSO<sub>4</sub> with NaOH to form the gell-like Cu(OH)<sub>4</sub>, and then dehyrate the gell with heat to
form Cu<sub>2</sub>O.
[Edited on 30-12-2004 by FrankRizzo]
[Edited on 30-12-2004 by FrankRizzo]
Mephisto - 30-12-2004 at 02:36
FrankRizzo: No, that’s not right. Cu (+IV) appears only with fluorine. Mixing dissolved CuSO4 with NaOH will give Cu(OH)2, which
decompose at 80 °C to CuO.
As Polverone said, the Cu(OH)2 had to be reduced with fructose or glucose to Cu (I). Depending on the temperature, the formed CuOH will decompose to
Cu2O. This variant of the Fehling test is called Trommer test - as it works without the Rochelle salt. It's made by adding CuSO4-solution to
NaOH-solution till a precipitation of Cu(OH)2 remains insoluble. Adding the fructose or glucose and slightly heating causes the formation of CuOH and
latter Cu2O. I think the yield of Cu2O won't be very high, but it's the easiest way to get Cu2O.
Breaking down Surcose
guy - 30-12-2004 at 12:57
Is there anyway to breakown surcose to fructose and glucose? I think you might have to use some dehydrating agent right?
budullewraagh - 30-12-2004 at 13:14
sucrase!
Marvin - 30-12-2004 at 13:26
Boiling with dilute acid will do it.
Citric acid will even do, its the 'invert sugar' method used for fermentation.
kryss - 2-1-2005 at 16:19
Instead of using glucose or fructose as a reductant you might be able to use ordinary sugar and caustic - you have to be careful with the
concentrations and heating though because its easy to overdo it and start breaking down the reducing sugars that are formed - if your not careful you
get a black gooey caramel type mess that boils over very easily.
Initially the sucrose is hydrolysed to your reducing sugars - the main problem is its easy to go on to dehydrate these.
[Edited on 3-1-2005 by kryss]