FlaskBreaker
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Phosphoric acid from Pepsi
I was watching a few Doug's Lab and Extractions&Ire videos, when I wondered: Would it be possible to extract the phosphoric acid from Pepsi? I
couldn't find any videos on this, which made me more curious. Luckily, I just so happen to have a nearly full pack of Pepsi. I looked at the
ingredients section of the label, and was surprised to find that the only ingredients are: Carbonated Water, Sugar, Caramel Color, Phosphoric acid,
Caffeine, and "Natural Flavor". Since it didn't have citric acid, which is what I was expecting, it would make the extraction a lot easier.
So this is my plan:
1. Let the carbon dioxide dissolve out of the Pepsi fully, eliminating the carbonic acid.
2. Slowly add calcium hydroxide, until a neutral PH is reached. This should make calcium diphosphate, which is insoluble in water and will precipitate
out.
3. Filter the rest of the Pepsi off, and let the calcium phosphate dry off.
What I can't figure out is: how would I reform the phosphoric acid from calcium diphosphate? If it was sodium phosphate, I could just add an acid to
it.
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Bert
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You can buy a 50lb. bag of Calcium phosphate for about $26.00.
But you'd learn more trying to extract from Coke.
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Bert
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Thread Moved
17-2-2018 at 08:00 |
FlaskBreaker
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But then you wouldn't have the fun of extracting it, would you? 
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Texium
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Of the words that come to mind when thinking about that extraction, "fun" isn't one of them.
I think eventually most people realize that the real fun lies in performing cool reactions with reliable chemicals, not in futile extractions that
require more money and time than buying a more reliable reagent.
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Bert
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If he actually DID it, he would at least learn how to use lab equipment? I did say "learn" not "enjoy". Also refrained from mentioning efficiency...
If I was headed towards "fun", I'd grab the bag of phosphate (or a big bag of bone meal!) and head towards the white Phosphorus extraction thread?
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FlaskBreaker
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Quote: Originally posted by Bert  | If he actually DID it, he would at least learn how to use lab equipment? I did say "learn" not "enjoy". Also refrained from mentioning efficiency...
If I was headed towards "fun", I'd grab the bag of phosphate (or a big bag of bone meal!) and head towards the white Phosphorus extraction thread?
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I know it would be pretty inefficient, I just want to see if you can do it. Kind of like how NileRed and ChemPlayer made citric acid from lemons.
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unionised
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You can certainly do it.
Treatment of calcium phosphate with sulphuric acid will produce calcium sulphate and phosphoric acid.
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AJKOER
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Reading the label is a path to finding several useful chemicals.
However, the weight of H3PO4 to be found is less than the weight of caramel coloring employed (which is not much).
--------------------------------------------------------------------------
Some stores sell STP (trisodium phosphate, Na3PO4), which could be a good pure source of starting phosphate. Try adding a source of oxalic acid (found
in rust removers,..) to precipitate out the sodium as sodium oxalate leaving H3PO4 and impurities. See my old thread at http://www.sciencemadness.org/talk/viewthread.php?tid=18963&... .
Expected reaction:
2 Na3PO4 + 3 H2C2O4.2H2O --> 3 Na2C2O4 (s) + 2 H3PO4 + 6 H2O
[Edited on 17-2-2018 by AJKOER]
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Magpie
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| Quote: Originally posted by Texium (zts16) | Of the words that come to mind when thinking about that extraction, "fun" isn't one of them.
I think eventually most people realize that the real fun lies in performing cool reactions with reliable chemicals, not in futile extractions that
require more money and time than buying a more reliable reagent. |
I think that "fun" is in the eyes of the beholder. This is a challenge of the "workup." You know you have the desired product, phosphoric acid,
dissolved in a mess. Now, how to get it out efficiently. It is more like a challenge in waste management.
A future employer might well be impressed with a chemist having the skill to create a process for doing this that actually worked efficiently.
The single most important condition for a successful synthesis is good mixing - Nicodem
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