Hello,
after getting help here in the forum a few days ago and then doing
a bit more research on my own, I finally managed to create the CuCL2
I needed, without requiring any H2O2.
Before considering this topic finished, I'd like to report my own observations
and experiences. Maybe they'll help someone else someday. I do not lay any
claim to the scientific correctness of the following text. Please bear with
me, I'm an amateur at best.
To remind everyone of the original problem: Normally CuCl2 can be created
by adding Cu to HCl, using some H2O2 to get the reaction going. Unfortunately
there was no way for me to source any H2O2, so that I decided to take a
somewhat indirect route in creating the CuCl2.
Chemicals available were Cu (stripped electrical wire), HCl, H2SO4, NaCl and
NaHCO3, and of course H2O.
In order to react the copper with the HCl, it has to be converted into a compound
which readily dissolves in HCl. To do so, an electrolysis of copper electrodes in
aqueous solution of different salts was performed, trying different solutions
to find the easiest/most efficient way (The Na2SO4-solution did prove fastest,
followed immediately by the NaCl solution).
As power source for the electrolysis an old computer powersupply was used. Those
units easily can provide currents in excess of 20A at voltages of 3.3V, 5V and 12V.
As electrolyte were chosen: NaCl (rock salt), H2SO4 (drain cleaner), NaHCO3 (baking
soda), Na2CO3 (created by heating of NaHCO3) as well as Na2SO4 (reaction of Na2CO3
with H2SO4).
Saturated / highly concentrated solutions of each of those compounds were created,
1 liter of each. A copper anode of around 100g of weight was placed at the bottom of
the solution, in a pyrex beaker. (Disclaimer: Okay, actually I used my coffee jug.
).
The cathode consisted of a copper wire bent into a ring, sitting in the same container
about an inch above the anode, so that any elementary copper forming on the cathode
would fall off and down onto the anode, where it would again be available for the
electrolysis.
Depending on which electrolyte was used, the following copper compounds were
formed: CuCl/CuCl2, CuSO4, Cu(OH)2, CuCO3. Most of the solutions would also form plenty
of CuO and Cu2O as the reaction advanced and the amount of copper in the solution increased.
Apart from those copper compounds and the salts initially introduced into the reaction,
the solutions also would contain some elementary Cu in powder form, as well as reaction
products such as NaOH. Plenty of H2 would be released, while much of the O2 would react
with the copper ions in solution, forming oxides.
After the copper anode had fully dissolved, the solution containing H2SO4 was neutralized
with Na2CO3 in solution, which was created by heating NaHCO3 and dissolving it in water.
Both the CuSO4 and the CuCl/CuCl2 were precipitated out by adding an excess of Na2CO3 in
solution, which would turn the CuSO4 and CuCl/CuCl2 into Cu(OH)2, a step which would
prove of advantage during refinement of the reaction products.
So, to recapitulate, after several hours of electrolysis and the precipitation with Na2CO3
I ended up with roughly two gallons of aqueous solutions containing Cu, CuO, Cu2O, CuCO3,
Cu(OH)2, as well as Na2SO4, Na2CO3, NaHCO3, NaOH and NaCl.
Time to seperate anything containing copper from all the sodium compounds. The 2 gallons
of solution were poured together, the water boiled off, and the mix of Cu-powder, oxides
and different salts of both copper and sodium was roasted at 250°C for several hours.
Almost all of our copper products were decomposed to CuO by the roasting, while the
sodium compounds remained largely unchanged. And here also is the reason for turning
the CuCl/CuCl2 and the CuSO4 into Cu(OH)2 earlier. CuCl and CuSO4 are still relatively
stable at 250°C, while the Cu(OH)2 would fully decompose to CuO. And while CuCl and
CuSO4 are quite well soluble in water, our CuO is NOT.
So we refine our wild mixture of sodium salts and CuO by washing out the sodium salts
and filtering off the CuO, then drying it.
We are left with almost 500 grams of black CuO, red Cu2O and some leftover copper powder.
All three are added to concentrated HCl, where the oxides will readily dissolve, forming
a solution of mostly CuCl, with some bits of copper still floating in the solution. More
HCl is added, then a fishtank airpump is set up to bubble air into the solution. This
should be done in a well ventilated place.
After some days the CuCl will have reacted with the excess HCl and oxygen from the
air bubbled into the solution.
4CuCl + 4HCl + O2 -> 4CuCl2 + 2H2O
The CuCl2 in turn will react with the copper impurities in our solution, turning them into
CuCl while being reduced to CuCl itself, ready to again react with oxygen and HCl. Eventually
our solution should contain almost exclusively CuCl2, HCl and of course H2O.
The solution can be used to etch printed circuit boards, which adds more copper. After use
simply regenerate by bubbling air into it, and occassionally add more HCl.
Best regards,
-Athrax