Sciencemadness Discussion Board

CuCl2 from copper sulfate ?

KonkreteRocketry - 28-3-2013 at 12:05

I want some CuCl2 for no reason, so will it work if i add CuSO4 + NaCl ? or KCl ? thats the only 2 chlorides i have....

DraconicAcid - 28-3-2013 at 12:11

You could do it by reacting copper sulphate with calcium chloride (since CaSO4 is insoluble), but you're better off:

a) Precipitating the copper out with sodium carbonate, and reacting the basic copper carbonate with hydrochloric acid.
b) Precipitating the copper with sodium hydroxide, heating the suspension to get easily-filtered copper(II) oxide, and reacting the copper(II) oxide with hydrochloric acid.
c) Adding copper wire to relatively concentrated hydrochloric acid (3 mol/L or more) in a shallow dish so that the solution is exposed to lots of oxygen from the air.
d) Copper wire, hydrochloric acid, and hydrogen peroxide.

With the last two, the reaction becomes faster as the concentration of copper ions in solution increases.

AJKOER - 30-3-2013 at 13:51

Quote: Originally posted by DraconicAcid  
You could do it by reacting copper sulphate with calcium chloride (since CaSO4 is insoluble), but you're better off:

a) Precipitating the copper out with sodium carbonate, and reacting the basic copper carbonate with hydrochloric acid.
b) Precipitating the copper with sodium hydroxide, heating the suspension to get easily-filtered copper(II) oxide, and reacting the copper(II) oxide with hydrochloric acid.
c) Adding copper wire to relatively concentrated hydrochloric acid (3 mol/L or more) in a shallow dish so that the solution is exposed to lots of oxygen from the air.
d) Copper wire, hydrochloric acid, and hydrogen peroxide.

With the last two, the reaction becomes faster as the concentration of copper ions in solution increases.


Now, a comment on reaction (a). My speculation is first the formation of the Copper Oxychloride with HCl (see Wikipedia http://en.wikipedia.org/wiki/Copper_oxychloride) and then, with excess HCl, CuCl2 forms. Reactions:

Cu2(OH)2CO3 + HCl → Cu2(OH)3Cl (s) + CO2 (g)

Cu2(OH)3Cl + 3 HCl → 2 CuCl2 + 3 H2O
--------------------------------------------------------
Net Reaction:
Cu2(OH)2CO3 + 4 HCl → 2 CuCl2 + 3 H2O + CO2 (g)

so a large excess of HCl is required.

I believe reaction (d) is more complex. HCl/H2O2 behaves like chlorine water. The action of the latter is reported to behave as follows:

"Reference: "A comprehensive treatise on inorganic and theoretical chemistry", Volume 2, by Joseph William Mellor, page 271. To quote:

"R. Chenevix notes the ready solubility of cupric oxide in chlorine water, and P. Grouvelle found that the soln. obtained by passing chlorine into water with cupric oxide in suspension possessed bleaching properties, and these were retained even after the soln. had been boiled for a quarter of an hour. A. J. Balard found that the distillation of P. Grouvelle's liquor furnished some hypochlorous acid and a green oxychloride, 3CuO.CuCl2.4H20, was formed in the retort. A. J. Balard prepared a soln. of cupric hypochlorite by dissolving cupric hydroxide in hypochlorous acid. It is also made by the action of cupric sulphate on calcium hypochlorite. A. J. Balard found that copper filings are partially dissolved by hypochlorous acid, the soln. after standing some time contains cupric chloride, and deposits a green pulverulent cupric oxychloride."

Link: http://books.google.com/books?pg=PA269&lpg=PA274&dq=...

So, possibly first the formation of some Copper hypochlorite and futher upon hydrolysis, CuCl2 and Cu2(OH)3Cl. My speculated reactions:

Cl2 + H2O <--> HCl + HOCl

Cu + H2O2 --> CuO + H2O

2 (HCl + HOCl) + CuO --> CuCl2 + H2O +2 HOCl

CuO + 2 HOCl --> H2O + Cu(ClO)2 (unstable)

2 Cu(ClO)2 + 3 H2O --> Cu(OH)2.Cu(OH)Cl + 3 HCl + 2 O2

For various possible forms of Copper oxychloride (Cu(OH)2.Cu(OH)xCly, see pictures and discussion at http://webpages.charter.net/dawill/tmoranwms/Chem_Cu.html ) and the HCl can act on the cupric oxychloride to form CuCl2 as noted above.


[Edited on 31-3-2013 by AJKOER]

violet sin - 30-3-2013 at 19:46

Copper + HCl + H2O2 has never gave me anything insoluble left but copper that was in excess of acid. No oxychloride scum/sedement. It's freaking simple in practice. No offence joker but you seem to see the complex side of a lot of rxns in paper. I have never had issues with any of the routes described above. Haven't tried all of 'em, but the majority sure. Again not being a jerk here, just my experience was .. Copper behaves nicely. Making diff copper salts is fun and easy, not to mention colorful :)

AJKOER - 30-3-2013 at 22:10

Violet Sin:

To quote Mellor, page 256 (http://books.google.com/books?pg=PA256&lpg=PA256&dq=... ):

"according to A. W. Williamson and J. Kolb, the metal chlorides are not attacked in the cold, and on warming the chlorates are formed. Hypochlorous acid precipitates the higher oxides from the chlorides of manganese, tin, lead, iron, cobalt, and nickel; and copper oxychloride from cupric chloride."

So, while I accept your personal experience here, I suspect that temperature may be one consideration with HOCl forming the oxychloride from CuCl2. Another may be concentration of HCl as dilute Chlorine water and H2O2 per Watt's favors the formation of some HOCl.
------------------------------------------------------------------------

The reaction of HCl and H2O2 is more complex, but don't believe me, here are some words from AndersHoveland (link http://www.sciencemadness.org/talk/viewthread.php?tid=14490 ):
"Reaction between hydrogen peroxide and hydrochloric acid

"The catalytic decomposition of hydrogen peroxide in either hydrogen chloride solution or with chlorine has been shown to be closely related to the two chemical reactions

H2O2 + (2)H(+) + (2)Cl(-) ---> Cl2 + (2)H2O

H2O2 + Cl2 ---> O2 + (2)H(+) + (2)Cl(-)

and is believed to be due to the occurence of these two competing reactions at equal rates."
Livingston and Bray, J. American Chem. Society, Volume 47, p2069 (1925)

In this reaction no net generation of chlorine results from the action of dilute solutions of hydrogen peroxide on hydrogen chloride, but there does exist an elemental chlorine intermediate in the reaction, which could potentially chlorinate enols.

When 30% concentrated HCl and 30% H2O2 is used then there develops a slight greenish yellow color and a faint but distinctive odor of chlorine, yet the gas from the bubbles is still mostly O2. I personally have conducted this expiriment and observed only moderate steady bubbling that persisted for several hours.

It is mentioned in the literature that chlorine gas is evolved from 30% solutions of HCl and H2O2, although in more dilute solutions, only oxygen is generated.
"Oxidation of Hydrogen chloride with hydrogen peroxide in aqueous solution" V.I. Skudaev, A.B. Solomonov"

Now, I would think that as Cl2 + H2O <--> HOCl + HCl, the solution of HCl/H2O2, in effect, contains some active hypochlorous acid, where the conc of the HCl employed is a factor.
---------------------------------------------------------

On the direct action of HOCl on metals, to quote from "Chemistry, inorganic & organic, with experiments" By Charles Loudon Bloxam, to quote a paragraph from page 115:

"The action of some metals and tneir oxides upon solution of hypochlorous acid is instructive. Iron seizes upon the oxygen, whilst the chlorine is liberated; copper takes both the oxygen and chlorine ; whilst silver combines with the chlorine, and liberates oxygen. Mercury yields, on shaking, the brown mercuric oxychloride. This distinguishes solution of HCIO from chlorine water. Oxide of lead (PbO) removes the oxygen, becoming peroxide of lead (PbO2) and liberating chlorine, but oxide of silver converts the chlorine into chloride of silver, and liberates the oxygen;

Ag2O + C12O = 2AgCl + O2. "

The link is:
http://books.google.com/books?id=vIQ-AAAAYAAJ&pg=PA455&a...

So my take on this is that HOCl, acting by itself, slowly forms the oxychloride with Copper metal.

[Edited on 31-3-2013 by AJKOER]

violet sin - 31-3-2013 at 04:25

Now I never said you were wrong about the details. I am wondering more about the concentration of these other species rather than their existence. Ya gotta figure with all the equilibria in effect in pure water, that there has to be a ton of things going on in a mix of several substances. But just as in water the more crazy the species generally the less of it kicking around. Further down that path, when stuff seems straight forward and proceeds straight , ie never had any issues making copper chloride, it kinda seems overkill analyzing it that far. And I'm sure there are plenty of YouTube vids showing how they made copper chloride, I just have not seen a case of people having difficulty with this. I even bubbled air from an aquarium pump thru solution trying to make the oxychloride, nada. But quite like you said I didn't really heat it much after the first time I tried to reduce a copper chloride sol. Ended up seeing lovely smokey vapors of HCl an said not again. So that may be why I have never seen that. I worked with pool acid, 3% peroxide and copper electrical wire. I have use the HCl + H2O2 to strip copper out from under gold plating for a few years now( just for fun not profit) and still haven't come across the oxychloride, that's why I was trying to make some.

Again not saying Your wrong about the well cited info, or others accounts of things, just going from personal experience. Most the ways stated above to make copper chloride have been easy


*above: by reducing a copper chloride solution, I meant in volume, not chemically if it wasn't obvious

[Edited on 1-4-2013 by violet sin]