Best ways to synthesize Copper Sulfate

[PeterB2]

Since I didn't see an existing thread on copper sulfate, post you're ideas and techniques for synthesizing CuSO4 here...and yes, I know you can buy the stuff, but I want to gain some more practical and simple lab experience.

Two methods that have worked for me so far:

1. Using copper electrodes for the electrolysis of a saturated Magnesium Sulfate in water. A blue precipitate that seems to be copper sulfate accumulates on the cathode. Periodically wipe the precipitate onto a paper towel and allow it to dry. You can synthesize a small amount this way in a couple hours (depending on the voltage, size of the cathode, etc.)

2. Mixing Sulfuric acid (I tried using battery acid of ~35% concentration and a lower concentration in an aquarium pH lowering solution) with a copper pot scrubber in a beaker along with about 8 g of KNO3 (I think most nitrate salt should work for this experiment). This experiment produces a lot of fumes, so do it outside or cover it with plastic wrap or something. Filter the reaction when it seems to have reached equilibrium and allow it to sit for a few hours and the CuSO4 precipitate should precipitate out of the filterate.

Any other ideas?

Does anyone know of any test I could use to test if these are indeed CuSO4, and, if so, how pure they are?

[Universal]

For no. 2 no KNO3 is needed, heat it up a bit. H2SO4 oxidizes Cu to CuSO4 in the reaction.

H2SO4 + Cu --> CuSO4 + SO2 + H2O.

It should react quite violently. To test for impurities, maybe bubble H2S through and see the different coloured sulfides, it should be black only if it is copper, if there are others then find out what they are.

[sprocket]

Universal: Sulfuric acid alone is not sufficient to oxidize copper and your reaction formula is unbalanced.

However, the following two methods could be used with success:

1. Oxidize copper to copper oxides by heating in air. These basic oxides will dissolve in sulfuric acid forming Cu2+-ions.

2. Oxidize copper in sulfuric acid using hydrogen peroxide. This is probably the easiest way to make pure copper(II) sulfate. Using hydrogen peroxide instead of nitrates has several advantages; most notably a purer product and easier separation.

One fairly easy way to test the purity of your product is a gravimetric method. First weigh an amount of fully hydrated copper sulfate, then proceed to dehydrate it (by heating to above 150°C). The anhydrous copper sulfate is then weighed and the loss of mass should correspond to the loss of 5 moles of water from copper sulfate.

[PeterB2]

Sprocket, I tried the latter method with H2O2. This one could be dangerous--I saw some unknown, rather thick brown fumes coming off the reaction which were pungent. It seemed to yeild a homogenous solution of sulfuric acid and aqueous CuSO4. I'm not quite sure the best way to separate them. Maybe boil it?

To me, that's the most obvious advantage of using a nitrate like KNO3--the solid CuSO4 precipitates out of the solution after a few hours (it did for me anyway...I'm not sure how atm pressure would affect it)

Universal, pardon my ignorance, but how do you bubble H2S through the solution? Do you need any special equipment to bubble gases through liquids?

I can take some pictures of the products and try to upload them if you like.

[megalomania]

I have from time to time needed some copper oxide, but I find it to be very pricy when copper abounds around us. Being the cheap bastard I am, why not let the banks bear the cost of my experiments? If you have the time and patience you can form your own copper compounds from pennies.

The reaction between copper metal and ammonia forms a hexaaquacopper(II) ion [Cu(H2O)6]2+. I place all of my pennies in a gallon jug of household ammonia and let them set. I have been doing this for a couple of years now. Over time the copper reacts and you get copper hydroxide precipitates once the ammonia concentration drops low enough.

You can also add some sodium bicarbonate to form copper carbonate precipitates, and react that with sulfuric acid to get copper sulfate.

My way is slow, but it just sits there over time. The pennies can be cleaned up, rolled, and deposited at the bank. Give the bank a few bucks and they will give you many rolls of brand new pennies to exploit…, er use.

Copper sulfate is sold at hardware stores in rather pure form as root killer for storm drains in quantities up to 5 pounds that I have seen. I believe it is also sold as a colorant for fireplaces (makes flames different colors for parties, get togethers, and such), but it is far more expensive that way.

http://www.roguesci.org/images/copper_bottle1.jpg
http://www.roguesci.org/images/copper_bottle2.jpg

[Cobalt.45]

You might want to sort those pennies first. 1981- back are ~95% Cu, newer are copper plated zinc.

[PeterB2]

Yes, new pennies are a great source for zinc--just use a dremmel or a grinder to shave off the thin layer of copper and you have the precious (not "valueable" per se) metal within. I havn't tried to make zinc dust yet, but I'm sure it would be quite easy.

Mega, would using a copper mesh pot scrubber (they're cheap--less than $1) increase the surface area of the reaction thereby speeding the process up? Also, I checked your "Controversial Chem Lab" site for your opinion on how to synthesize copper sulfate but it wasn't there yet. Do you plan on doing any more on that site? There's some great stuff there and I would like to see how you do some other sytheses. Keep up the great work on that site!

The only test I currently have to test for sulfates it to add H2O2 and a base (baking soda works great) to the sulfate in question. In the case of copper sulfate, the mixture turns tar black and bubbles. I'm not sure exactly what's going on chemically there, buts its very interesting and seems to be a more or less accurate test for copper sulfate. Perhaps the copper is being oxidized to Cu+2? With all other sulfates (that I've tried so far), the mixture bubbles but does not produce any color change.

[sprocket]

Sprocket, I tried the latter method with H2O2. This one could be dangerous--I saw some unknown, rather thick brown fumes coming off the reaction which were pungent. It seemed to yeild a homogenous solution of sulfuric acid and aqueous CuSO4. I'm not quite sure the best way to separate them. Maybe boil it?These brown fumes are something of a mystery to me. Are you sure you haven't confused the hydrogen peroxide experiment with the potassium nitrate one? Because the oxidation with nitrate would indeed produce brown fumes, unlike oxidation with hydrogen peroxide.

Although the hydrogen peroxide method seemed good at first I'm starting change my mind. It works great for making copper(II) chloride with hydrochloric acid, but that's mainly because the copper-chloride complexes help dissolve the copper. This is not the case with sulfuric acid; copper does not form complexes (at least not to a large extent) with the sulfate ion. Thus the rate of reaction is much lower in the sulfuric acid solution.

Separating the copper(II) sulfate from the solution can be done by crystalization followed by filtration. Washing the crystals with an organic solvent is probably a good idea as well.

[DONMAN]

Would it be possible to react a copper compound with some sulfate salt?

[Alexires]

It says on the net (here (http://www.copper.org/applications/compounds/copper_sulfate01.html)) that copper sulphate can be produced through heating copper with sulphur to make copper sulphide which is then oxidized to copper sulphate. Otherwise there is Copper Oxide + H2SO4.

[nbk2000]

I remember making copper sulphate by boiling cut up copper wiring in dilute sulfuric acid (~33%) with a spoonful of sodium nitrate added in to kick it off.

It made the most beautiful blue crystals. :)

[Sworn]

Yes, this seems a nice procedure. Here is the formula to the process.

2 Cu + 2 H2SO4 + O2 -----> 2 CuSO4 + 2 H2O

I belive there is more than one way to make the product. I have modifyed a simple reaction between calcium sulfate and copper(II)chloride. There are the orginal formulas. The process will not work with magnesium(II)sulfate, the magnesium chloride is difficult to remove. The hexahydrate dissolves with around 1670 g per litre in water.

2 KCl + 2 MgSO4 + 6 H2O -> K2SO4 * MgSO4 * 6 H2O + MgCl2
K2SO4 * MgSO4 * 6 H2O + 2 KCl -> 2 K2SO4 + MgCl2

Calcium sulfate dihydrate seems useful with around 2 g per litre.

2 CuCl2 + 3 CaSO4*2 H2O + 5 H2O -> 2 CuSO4*5 H2O + CaSO4*2H2O + 2 CaCl2
2 CuSO4*5 H2O + CaSO4*2H2O + CuCl2 + 5 H2O -> 3 CuSO4*5 H2O + CaCl2 + 2 H2O

A mixture of 2 mol copper(II)chloride powder, 3 mol calcium sulfate dihydrate powder and 90,5 mL of water is heated in a large beaker below the thermal decomposition of the copper(II) sulfat. (around 88 degree C) The beaker should be sealed and mixture is stirred sometimes. After some hours, a mixture of copper(II)sulfate and calcium sulfate should have formed, open the beaker, the mass is dryed and grindet with a motar, placed to a new beaker and a second portion of 1 mol of copper(II)chloride powder and 90,5 mL of water is stirrd to this. The procedure is continued exactly as the previous step and the obtained mass is added to around 2400 mL of water, filtered and the blue solid of copper(II)sulfat pentahydrate is then collected by vaporizing the water.

In my opinion, as a possible issue to obtain the copper(II)sulfate is the process to generate sufur dioxide and oxygen (ratio 2:1) and the gas is bubbled into a mixture of 2 mol of copper(II)chloride and 126,5 mL water. It happens the dryed product is polluted with some hydrochloride but it should useful.

2 CuCl2 + 2 SO2+ O2+ 7 H2O -> 2 CuSO4*5H2O + 4 HCl (hydrogen chloride) + 2 H2O

A reaction between copper(II)nitrite and copper(I)iodide in concentrated sulfuric acid seems useful, if it exist. 2 mol of grindet copper(I)iodide is stirred to 4 mol of sufuric acid >99%, 1 mol of copper(II)nitrite powder is added in small portions and the mixture is stirred is continued until no fumes of nitrogen oxides will bubble off. Cool the mixture if necessary and hold the temperature below 88 degree C. The mass is added to 3200 mL of water, filtered and the copper(II)sulfat pentahydrate is collected by vaporizing the water.

2 Cu(NO2)2 + 2 CuI + 4 H2SO4 -> I2 + 4 CuSO4*H2O + 4 NO

This procedures are something costly and precisely worked but seems useful.
If there is more to a copper(II)nitrite procedure, please post your suggestions.
Any thought to my issues ?

[DONMAN]

I have from time to time needed some copper oxide... If you have the time and patience you can form your own copper compounds from pennies.



I have started this process, about how long will it take for the precipitate to form? Weeks? Months? I am using copper wire ..... that should speed up the reaction. My solution is very blue now, but still no precipitate. It's been about 5 days now.

[megalomania]

I'm thinking months, although I just let mine sit, so I don't know when it precipitated. I think I have had my penny jug for about 2 years now.

The more copper ions in solution, the sooner the ammonia won't be able to dissolve them, and then you get a precipitate. The precipitate pulls copper ions out of solution (as a hydroxide) allowing for more copper ions to enter the solution (from copper metal). Lather, rinse, and repeat...

I recommend agitating the copper from time to time. It seems to form a scale that reduces surface area after awhile.

[Universal]

This seems like an awful amount of trouble to go to to make CuO. I made it by mixing CuSO4 with Al, and collecting the Cu powder. I wash it until it is nice and clean. Then I let it dry. This makes a fine powder. I then heat this up with sulfur in the roght amounts, it turns to CuS, I then heat the CuS and high temperature until SO2 stops being made and CuO is left.

[DONMAN]

But your way is more expensive.... The old saying is,"you have time or you have money.":rolleyes:

[nbk2000]

If you're using aluminum foil or cut-up soda cans, plus scrap copper, it shouldn't be expensive at all.

Universal, how fine is the copper powder you get? Flour fine?

Pure copper powder has many uses, not the least of which is as a filler for flexible LSC liners. :)

[Universal]

The copper is not flour fine, unfortunately, but much finer than say salt or sugar. If you mill it, or mortar and pestle it like me, it is almost as fine as flour. And yes, it isn't very expensive, just the SO2 is a bit annoying ;)

[megalomania]

I bought some copper oxide about 2 years ago and it struck me as being very expensive for what little I got. Since I have enough CuO on hand to last me awhile, and I have the idle time for the pennies to soak, I figured why not. Except for the ammonia, this process is almost free if you cash in the pennies after exploit..., err, utilizing them.

Every person has different motives and goals when it comes to obtaining and using chemicals. Those that can get chemicals easily and cheaply, god speed, but for the have nots, or the have littles, any way you can get your fix is a good way.

[nbk2000]

Perhaps if the solution was rapidly stirred (mechanically) during the precipitation process it would be much finer.

Something for you to try, as extremely fine CuO mixed with Aluminum powder in an explosive binder forms very powerful explosives. :)

[inventorgp]

Here's a site/vid NBK,

Site: http://geocities.com/roguemovies9/index.html
Vid: http://geocities.com/roguemovies9/copper-oxide-aluminium-target.mpg
That was shot at.

Thats one of them but, Geo seems to be down some times. And I can't get a FTP working.

[nbk2000]

Dude...that site is so old. :p

It was originally put up by Axt before he got banned for his stupidity here.

[TimedReport]

I am mostly interested in fireworks, but have become increasingly interested in making high ex and sythesizing my own chems. This was mainly brought on because of the CPSC and their move to ban all chemicals in an effort to create their communist, bliss-ninny utopia.

Anyway, this is my first post here, so hopefully it can be helpful to someone. After the CPSC started in with their stupid nonsense, I started focusing on ways to buy chemicals through sources other than chemical supply companies. It becomes clear that many of our chemicals are used in other industries and merely telling a lie to the proprietor as to who you are and what you want it for will yield fantastic results. Of course, in some cases you don't have to lie, but I digress.

Copper compounds are no exception (although you don't have to give them a story). Here are two sites that sold the absolute cheapest copper compounds that I could find. I actually bought from them and they sent the forty and fifty lb buckets to me through the mail. I bought Calcium Carbonate, Copper Carbonate, Copper Oxide, and Barium Carbonate. The prices, per lb, were $0.24, $3.95, $3.38, and $1.18, respectively. Of course, you have to buy a lot (10 lbs ranging to 50 lbs at a time).

I haven't tested anything for purity, but the chemicals work fine in color and glitter stars. They are at least technical grade, I would assume.

Good Luck,

Joel



http://www.seattlepotterysupply.com/Merchant2/merchant.mvc?
http://leslieceramics.com/artman/publish/article_143.shtml

[chembio]

You could try using copper (II) nitrate and sulfuric acid. I believe the equation would be like this:

Cu(NO3)2 + H2SO4 -----> CuSO4 + 2HNO3

This reaction would give you copper sulfate AND nitric acid. From most of the posts I've read, HNO3 is a hot item among fellow forum members.

Or if you want to use copper oxide, I would try this method:

________________________O
l
l_____P_________A________O

H1 H2

This diagram represents an experiment setup (in a boiling tube). The symbols:

A - Copper
P - Potassium permanganate
O - Glass Wool (plugging the mouth of the boiling tube)
H1/H2 - Heat.

Heat the copper until it melts. Then, heat the KMnO4 to release oxygen. The reaction should end with the oxidation of the copper.


Hope this helps! :)

[Vigo]

A little aside:
when you have obtained copper sulphate by whatever method, take care not to inhale the dust as around here in Switzerland it is classed 3 on the poison scale (from 1 to 5).