Axismundi000
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Malachite and acetic acid.
I know it is possible to make a kind of malachite pigment from acetic acid starting with copper hydroxide but if I have too much acetic acid does it
continue onwards and become copper acetate?
The basic online chemistry equation balancer gives this for malachite and acetic acid.
4CH3COOH + Cu2CO3(OH)2 = 2Cu(CH3COO)2 + 3H2O + CO2
So presumably if I have an excess of acetic acid and the 'malachite' I get copper acetate?
Hope you guys don't mind me asking such basic stuff but if you do mind, my apologies and just don't respond.
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MrHomeScientist
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Do you have a link to the procedure you're following? It would depend on what the pigment requires; if it's all copper acetate, an excess of acetic
acid is what you want since that will convert it fully. If the pigment is some mixture of hydroxide and acetate, you'd need the corresponding amount
of acetic (less than stoichiometric).
For future reference, such questions are better suited to the Beginnings subforum. Welcome to the forum!
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Magpie
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This "Crystal Growing" thread will give you a wealth of information:
https://www.sciencemadness.org/whisper/viewthread.php?tid=55...
The single most important condition for a successful synthesis is good mixing - Nicodem
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Fulmen
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If your goal is to make pure malachite from other copper salts I don't see how acetic acid could be useful. Malachite is a basic copper carbonate,
there are (at least) two forms with different compositions (malachite and azurite IRRC), and their formation is sensitive to both temperature,
concentrations and pH. A direct precipitation with a carbonate is the obvious route, but tends to produce mixtures of these.
Such direct precipitations also tends to form very fine particles, creating a mud that will barely filter out. The best method is to redissolve this
precipitate in ammonia, then boil off the ammonia. This produces a dense precipitate of pure malachite that is much easier to process.
We're not banging rocks together here. We know how to put a man back together.
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Texium
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Thread Moved
18-5-2017 at 08:43 |
Axismundi000
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Thanks for the pointers.
I was just wondering why acetic acid didn't go to copper acetate when the online equation balancer shows a actual formula. Clearly the quantity of
acetic acid is key when wanting artificial malachite rather than copper acetate because acetic acid will react with the malachite to give copper
acetate. Appreciate the clarification.
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