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Author: Subject: copper acetate and copper powder - electrolysis.
brew
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[*] posted on 16-12-2008 at 01:49
copper acetate and copper powder - electrolysis.


I have wanted to make copper(11) acetate, so I thought why not add store bought aprox 5% white vinegar - 500ml, in a single cell, with two copper tubes as electrodes, with around 11V(using just a battery charger here) and around 2 amps running. The vinegar solution within 2-4 hours becomes blue, and after about 12-18 hours I have collected the solution and seperated precipitated copper and have evaporated of the solution thus forming incredibly beautiful deep blue/torquoise crystals - of copper acetate. I haven't got a camera at present as I would like to show the picture. I have checked out a visual of the copper acetate and they look the same. they smell of acetate, I dont think this can be disputed. The mechanism I think, is the hydrogen of the acetic acid goes to the cathode thus gaining an electron and bubbling up, the acetate anions then go to the anode thus forming the metal acetate, this is soluble, hence the copper goes to the cathode, gains an electron and this forms the copper powder precipitate, the anions head back to the anode which then forms the metal acetate again and this repeats. I think this is what is occuring here.

I haven't crunched numbers in this as yet. I haven't worked out the amp hours, and purely checking the pot and pending on the intensity of the solution etc, I either continue or stop,. this I believe is a really simple way of gaining two useful reagants, and able to be done so very easily. My apologies if this has already been discussed. I have quickly looked and noticed a few other methods, but this very much I believe encompasses two useful reagants. It is so OTC. Worthy of including I felt, albeit incredibly simple.
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[*] posted on 16-12-2008 at 16:53


Indeed, a successful preparation. Congrats on the beautiful crystals. ;)

Your theory is correct, and indicates exactly why this process is so inconvienient: due to the copper plating out, your efficiency will be somewhere between nearly 100% (if you run so little charge that barely any copper entered solution and therefore none plated out) to nearly 0% (if you run so long that the addition of copper at the anode is exactly balanced by metal plating out at the cathode and the concentration in solution therefore remains constant).

The best method to prepare metal salts such as copper sulfate or chloride is to prepare the oxide, then dissolve in acid and crystallize. The chemistry of this reaction is posted all over (particularly in the "copper salts" thread), have fun.

Tim




Chemistry section: http://webpages.charter.net/dawill/tmoranwms/Chemistry.html

"I could take measurements, but why bother? Science just slows down chemistry!" - Myself
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brew
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[*] posted on 17-12-2008 at 01:33


I didn't mention this in my description, but I'd casualy check every few hours, and wipe the electrode, or swop the leads. Which gave me a middle ground efficiency. And also a supply of copper, in a purified form. I do have copper sulphate, and I could of changed that to its oxide, but initially thought that wouldn't react with the 5% acetic acid, being so weak, but on second thoughts it would. So I will try it. I can make GAA but that is sort of a hasstle . This just seems an easy OTC method for these reagants when perhaps a small amount is necessary, as catalysts from time to time.Plus it is a hasstle free, drama free process, just check in on it every 3 hours etc... I stilll cant get over the crystals, I have never seen anything so spectacular, the color is extraodinary, also knowing that acetates are somewhat delicate, I dried it on a water bath, set on warm, which made the crystals form very nicely. I tend to get a camera soon, and will begin posting such images.

As far as preparing other salts, I check this forum regularly, and look for the best ways all the time. Cheers.

[Edited on 17-12-2008 by brew]

[Edited on 17-12-2008 by brew]
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[*] posted on 29-12-2008 at 16:42


Tim,

With that said, I do realise that my thread is somewhat pointless and doesn't promote discussion - or really intersting chemistry. If I could push the rewind button or remove this thread, I would. Perhaps the moderators could do this for me. I just got blown away by the formed crystals and the ease of obtaining two useful chemicals albeit not realising that one can just make these reagants very easily and also without alot of activity and messing around. I also wanted to contribute to a forum, I get so much out of, and it was late in the day, and I got carried away. Before I post again, I will attempt to ensure that what I state is somewhat of interest not only for myself but for others. I will do a good search and make sure I am not covering old ground, or ground that is somewhat pointless. Perhaps if this thread remains, I will discuss future experiments with the copper salts in question.

brew.
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