PoWEr
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Sulfuric Acid from Ammonium Persulfate
Without any backstory, I found out that ammonium persulfate is very close to sulfuric acid and with simple reactions you could get H2SO4 out of it.
I belive this method is easier to clean since there is no sulfur burning & residue and you use less lab equipment than you would in hydrogen
peroxide method. In terms of acid purity, I would either place it between CuSO4 and hydrogen peroxide method, or even next to or after hydrogen
peroxide method. This is a speculation for now, refer to the text below.
This method is only on paper for now, hope to actually test it out soon. Wanted to share this with you guys so I can get some feedback on what to
improve/change. This is what I've got so far:
List of reactants used:
- (NH4)2S2O8
- Distilled Water
- KI
- Starch
- CoSO4 * 7H2O
- dimethylglyoxime (dmg)
- H2SO4 (can be diluted)
Main reaction:
2(NH4)2S2O8 + 2H2O --> 2(NH4)2SO4 + 2H2SO4 + O2
1. Prepare ionide-starch test
2. Add just enough sulfuric acid to the cobalt salt to make it wet
3. In a boiling flask add the cobalt salt (It will be the catalyst), then add ammonium persulfate, distilled water and finally some drops of sulfuric
acid to make it a slighty acidic environment
4. Turn on gentle stirring and crank the heat to 70-75C
5. Cover the top with a watch glass (to prevent water from escaping, but let the oxygen gas to escape)
6. Make sure to add distilled water from time to time
7. When adding distilled water doesn't do anything, stop the stirring and turn off the heat and wait for it to cool down
8. Take a small sample and test if ionide-starch test is positive (if it is, then keep the reaction going)
9. Add to the made solution some dmg and mix it well, then let everything separate and get rid of the cobalt complexes and leftover dmg
10. Lastly, distill the solution to get rid of water and make (NH4)2SO4 crystallize.
Originally I thought of using MnO2 as a catalyst, but then I realized It will be a mess to clean. CuSO4 is just extra steps to clean and lower quality
acid and CoSO4 is the best candidate I've found so far (easy to separate out). Adding catalyst is important here to make sure almost no H2O2 forms - I
originally found about this reaction while reading about hydrogen peroxide, historically it would be produced by the same reaction but in a cold
environment and no catalyst.
Adding tiny amounts sulfuric acid to the entire solution inside boiling flask is to make sure that there are no side byproducts.
Temperature is between 70-75C to make sure water evaporates slowly but still make the reaction occur faster.
[Edited on 3-5-2025 by PoWEr]
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teodor
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Is there any results of your experiment already?
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PoWEr
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Not yet, today in the morning I bought online some dmg - It's not the cheapest stuff and tiny amounts I found in my "lab" are not enough. I should get
it the following week.
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woelen
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You might be able to get dilute and somewhat impure H2SO4 from your reagents, but isn't this a very expensive way of making dilute H2SO4?
I see you are in the EU, so you can buy 15% H2SO4. Isn't that much more economical?
Your reaction certainly is interesting, from a scientific point of view, and may be interesting for people in other parts of the world, where there is
no H2SO4 at all, but in the EU I think it is cheaper and more practical to simply buy 15% H2SO4 and if you need higher concentrations, up to 50+
percent, you simply boil off water.
An affordable alternative is 70% methanesulfonic acid, which is nearly as strong as sulfuric acid, but is available at much higher concentration, and
has the added benefit of not being oxidizing at high concentration and higher temperatures.
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Radiums Lab
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I agree with woelen about the cost, you can even get 98% purity from 15% if you have setup.
Water is dangerous if you don't know how to handle it, elemental fluorine (F₂) on the other hand is pretty tame if you know what you are doing.
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Radiums Lab
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Method of preparing is good though.
Water is dangerous if you don't know how to handle it, elemental fluorine (F₂) on the other hand is pretty tame if you know what you are doing.
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