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Alkoholvergiftung
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Befor ww2 H2O2 was industial made by hydrolysis of Ammoniumpersulfate. Maybe you should try elektrolysis of Ammoniumsulfate.
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Mister Double U
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Alkoholvergiftung,
I heard that Ammonium Persulfate is presumably easier to create than the others. And I also read in a patent that this was used to make H2O2. So,
maybe you are right, and it also hydrolyzes better than the other persulfates.
I will give it a try, but I will need to make it with previously distilled H2SO4 to prevent contamination...
Beste Gruesse :-)
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clearly_not_atara
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Ammonium sulfate is much more soluble than sodium or potassium sulfate, so the yield should be better and the conductivity higher
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Mister Double U
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clearly_not_atara,
Currently distilling some H2SO4 to make a fresh batch of NH4HSO4 through Urea hydrolysis (DEF solution, since it is supposedly very clean).
I am planning to use a Tyvec wrap around the cathode to prevent reduction - so let's see how that goes :-P.
Concerning using straight Ammonium Sulfate: I think this would require a divided cell, so the liberated Ammonia does not interfere with the reaction
by the following equations.
2(NH4)2SO4 -2[e-] -> (NH4)2S2O8 + 2NH3
2NH3 -8[e-] -> NH4NO3
If NH3 concentration is very low, most of it becomes oxidized to nitrate on Platinum or BDD anodes. In other words, only 20% of the current would be
used to generate Persulfate.
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Mister Double U
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H2O2 by Ammonium Persulfate Hydrolysis & Vacuum Distillation
Hello Folks,
As promised, I finished electrolyzing the NH4HSO4 solution. And it is currently distilling.
Volumen: 500ml
Concentration: 400g/l
Current: 2A
Duration: ~30hrs
Anode: BDD (10cm^2)
Cathode: Titanium mesh wrapped in 2 turns Polyethylene cloth.
(Cathode was etched in 20% HCl for 10 hours before use)
As discussed previously, the Ammonium hydrogen Sulfate was made by boiling freshly distilled H2SO4 with DEF in the correct proportions.
After the electrolysis was finished, the solution was heated to ~50C and kept at that temperature for 6 hours to facilitate hydrolysis of (NH4)2S2O8
to H2O2. Interesting enough, the solution changed color from completely colorless to red/orange again - like in my first experiment. So I assume there
is some Titanium contamination. likely from the holder of the anode which is made from Ti. At this stage I take this as something positive as I think
it is the Ti-peroxo complex. So, in other words, there is H2O2 in solution :-).
During the 6 hours hydrolysis only very few tiny decomposition bubbles were observed.
As distillation started, no decomposition bubbles were seen - only big boiling bubbles.
Pictures:
Boiling flask:
Temperature at beginning of distillation:
Pressure:
Electrode setup:
Cut PE cloth (believe was a bag a pillow came in):
I'll post about the results once distillation is complete.
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Mister Double U
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Failure Again
Just tested the distillate by the usual copper wire and boiling method.
No gas evolution was observed. Quite disappointing - I thought things looked good.
Not sure what I can change at this point. Feel a little beat down :-(
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Radiums Lab
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Hydrolysis of Na2O2 gives H2O2. If Na can be made using electrolysis then Na2O2 is easy to get.
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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@Mister double U, try with Pt, It will give you less disspointment compared to Cu.
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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Mister Double U
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@Radiums Lab,
I heard that Sodium can be burned in excess Oxygen to yield Sodium Peroxide.
Doing molten salt electrolysis with either NaCl or NaOH is a different animal though, with both routes posing unique challenges regarding temperature
control, material choice and exclusion of atmospheric Oxygen. In other words, I am unsure if this would be an easier route.
Concerning the Pt/Cu, I am unsure how this comment is meant. Currently I use Cu wire to test, if H2O2 is present, which has worked well (decomposition
and O2 formation). In my last experiment it just showed there was no H2O2, which was disappointing.
Is that what you meant, or was your comment aimed at something else?
Thanks for your response though - good to have some interaction going :-)
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Radiums Lab
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Pt as you know is one of the best catalyst, what I meant above was that Cu cannot detect the tiniest
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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amounts of H2O2 but Pt can detect even tiny amounts of H2O2 due to its high adsorptive nature.
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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I think this run your setup made way less H2O2 than what Cu can detect, +try testing with KMnO4.
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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Mister Double U
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@Radiums Lab,
I see where you are going with the Pt.
On the other hand, it would be nice to have a procedure, which can produce usable quantities of H2O2. If I have to detect trace amounts of H2O2 I
think I would consider the synthesis a failure anyway :-/
The procedure of hydrolyzing S2O8[2-] to H2O2 was successfully performed in the past, but it seems hard to find sources which describe it in detail.
Anyway, I am currently electrolyzing the next batch of Ammonium Hydrogen Sulfate. I will test 50ml of it to see how much Persulfate was generated. If
that yield is acceptable, I want to see, if addition of Phosphate can help stabilize some of the H2O2 (or some other stabilizer)...
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Radiums Lab
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Please update once your experiment is done. You can always concentrate the H2O2.
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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Mister Double U
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Just tested the second ammonium persulfate solution. Please note that this is not the distilled H2O2 but the raw Persulfate solution. If there was any
Persulfate ist was only present in trace amounts.
Here the picture of Copper immersed in the solution after some hours (no blue color visible):
I noticed during the electrolysis that a lot of gas was produced at the anode. I wonder, if there was still a lot of un-hydrolyzed Urea in the
solution, which got oxidized to N2 and CO2 - that is at least my hypothesis.
Anyway, I switched back to NaHSO4 with the current setup. I had tried the electrolysis of NaHSO4 in a flowerpot cell in a prior run but had too much
contamination. This was indicated by a lot of decomposition during the distillation (the red color in terracotta is probably from Iron).
Here a picture of the cell running again. It looks like there is a lot of gas coming from the anode, but most of the bubbles are stationary on the
electrode and only few come off here and there. This can also be seen on the liquid surface, as there are very little bubbles there (@2A).
Next steps: I will test the cell liquor by the usual way once complete and then distill with/without prior hydrolysis and/or added Phosphate.
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Mister Double U
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Here the results for the Persulfate content of the NaHSO4 electrolysis:
2.47g of Copper were dissolved. That means there were 10.1g Na2S2O8 in the 100ml sample -> 50.5g in the batch after ~24 hours of electrolysis.
Current efficiency: 23.6%
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chempyre235
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This is a little bit of a different angle, but I recently found some info on reduction of oxygen with electrochemical catalysis by
phthalocyanine-transition metal complexes. As these usually use iron or cobalt (which are both easily obtained) and phthalocyanine (which is made from
urea and phthalic anhydride), which make this a theoretically feasible approach for the amateur as well. The main difficulty to hydrogen peroxide is
preventing the decomposition to water. Maybe an additive that would form an adduct, such as urea, could be the solution.
https://advanced.onlinelibrary.wiley.com/doi/full/10.1002/ad...
https://en.wikipedia.org/wiki/Oxygen_reduction_reaction
https://en.wikipedia.org/wiki/Phthalocyanine
P.S. The Wiley reference is behind a paywall, so I haven't read the full text.
[Edited on 9/5/2025 by chempyre235]
"However beautiful the strategy, you should occasionally look at the results." -Winston Churchill
"I weep at the sight of flaming acetic anhydride." -@Madscientist
"...the elements shall melt with fervent heat..." -2 Peter 3:10
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Mister Double U
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Hello chempyre235,
I am not sure how easy it would be to make the Phthalocyanine.
As you stated, you will need Phtalic Anhydride which doesn't seem to be too easy to make. Wikipedia says that it can be done with a Mercury catalyst
in liquid media oxidizing Naphtalene. Alternatively, I read it can be oxidized in gas phase on a Vanadium catalyst. Then you still need to do the
reaction & purification which yields the Phthalocyanine. This route does not seem easy to me - not saying it can't be done :-).
Thank you for joining the discussion! It would be cool, if someone would start experimenting on the cathodic generation of H2O2 and then in the end we
could see which process is better. I read somewhere that a carbon fiber cloth was used as cathode material in an NaOH electrolyte and then O2 was
bubbled through it. As far as I remember, no additives were needed, but I might be wrong.
Anyway, we'll get this done some time :-D
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Mister Double U
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Here the result of the last distillation attempt - failure:
Before I started distillation, I heated the solution to ~60C (when small bubbles started forming) for a couple hours. Then I let the solution cool and
started vacuum distillation.
At the end things became very foamy and some material spilled over into the collection flask. I still tested the distillate and observed some small
bubbles, but I attributed them to the spilled-over Na2S2O8.
To exclude contamination as the culprit for poor Hydrogen Peroxide yield, I added commercial 3% H2O2 to the residue from the first distillation and
distilled again. At least some H2O2 made it over. In other words, it looks like the hydrolysis step is the problem in this whole endeavor.
Boiling flask after first distillation:
H2O2 from distillation of purchased 3% solution & residue:
[Edited on 6-9-2025 by Mister Double U]
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Mister Double U
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Here some suggestions ChatGPT-5 gave for the process:
Key Hydrolysis Conditions (from US Patent US3694154A)
A relevant patent details the concentration and hydrolysis steps used in industrial practice:
1. Concentration Step (Evaporation)
Pressure: 0 to 200 mm Hg absolute, ideally 30–120 mm Hg to minimize H₂O₂ loss.
Temperature: 50–85 °C, preferably 55–75 °C, again aiming to preserve H₂O₂.
Residence time: Very short—typically from a fraction of a second to about 200 seconds, with ≈10 seconds being common.
Objective: Concentrate the peroxydisulfate solution without significant hydrolysis occurring yet.
2. Heat Treatment (Hydrolysis Stage)
Pressure: Atmospheric or slightly above (not more than 1 atm gauge).
Temperature: Near the solution’s boiling point—approximately 105–130 °C, usually below 150 °C.
Water content: Kept between 25–45%—this retains H₂O₂ in solution and avoids driving reverse reaction via evaporation.
Residence time: At least enough to convert ~85% of per-oxygen content to H₂O₂, generally 5–15 minutes works very well.
3. Steam Stripping (Optional)
After hydrolysis, live steam can be used in a counter-current process to strip H₂O₂ into the vapor phase, achieving an H₂O₂ vapor
concentration of ~2%.
So maybe hydrolysis should be attempted after concentration is what I get from this...
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Mister Double U
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Experiment with Phosphate Addition - Small Success
Hello,
As mentioned, I also wanted to conduct a run and see which effect PO4[3-] has on the whole process.
NaHSO4 electrolysis was carried out as in the previous runs (500ml, 125g, 2A, wrapped cathode). After that 30ml of a solution containing ~8g Sodium
Phosphate (mono & di) were added to the cell content. Unfortunately, the solution also contained some Na-EDTA (enema solution - Walmart).
Here the next steps:
1. A white precipitate formed, which I assume consisted mainly of the acid form of EDTA and was filtered off.
2. The volume of the solution was vacuum distilled down to ~250ml.
3. Vacuum was removed, and solution was heated to almost boiling and some foaming started - heat was then cut off and solution left to cool for ~2hrs.
4. 150ml of distilled water were added and vacuum distillation was repeated until nothing came over anymore.
Both the distillates from the first and second vacuum distillation were tested by the usual heat + Copper way and did contain small amounts of H2O2.
Interestingly, judging from the bubbling they seemed to contain roughly the same amounts. One would think that the second (after hydrolysis) batch
would contain more. I am guessing the solutions contained somewhere <0.5% H2O2. I did not conduct quantitative testing.
Lastly, the addition of PO4[3-] seemed to have helped. Almost no red/orange color was visible during any of the distillations - only a very faint hue
during the hydrolysis step. Also, at the end of the distillations things did not get super foamy like in the previous run and the second one could be
driven to the point where nothing came over anymore.
Hydrolysis (the cloudiness is actually very fine foam on top of liquid):
Peroxide decomposition on Copper:
At the moment I need to scratch my brain to see if there are any good ideas coming out of it regarding how to proceed. I am thinking about running
another Potassium Persufate batch and then try to hydrolyze it in just the right amount of H2O so the KHSO4 can fully dissolve, but K2S2O8 can't. This
way one would have a visual indicator of how the hydrolysis proceeds and see when it is complete.
Off track: I have also thought about doing the carbothermic reduction of BaSO4. Maybe the resulting BaO could then be oxidized to BaO2 in an oxidative
melt with KClO3?
Anyway, best greetings!
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chempyre235
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Quote: Originally posted by Mister Double U  | Hello chempyre235,
I am not sure how easy it would be to make the Phthalocyanine.
As you stated, you will need Phtalic Anhydride which doesn't seem to be too easy to make. Wikipedia says that it can be done with a Mercury catalyst
in liquid media oxidizing Naphtalene. Alternatively, I read it can be oxidized in gas phase on a Vanadium catalyst. Then you still need to do the
reaction & purification which yields the Phthalocyanine. This route does not seem easy to me - not saying it can't be done :-).
Thank you for joining the discussion! It would be cool, if someone would start experimenting on the cathodic generation of H2O2 and then in the end we
could see which process is better. I read somewhere that a carbon fiber cloth was used as cathode material in an NaOH electrolyte and then O2 was
bubbled through it. As far as I remember, no additives were needed, but I might be wrong.
Anyway, we'll get this done some time :-D |
Phthalic anhydride can also be oxidized in solution by potassium permanganate or potassium dichromate: both of which are readily available in the US.
I'd assume that a solvent like vinegar would be sufficient to dissolve both the naphthalene and the oxidant. From there, the phthalic acid would need
to be removed and heated to dehydration. Fuming sulfuric acid can oxidize naphthalene as well.
Alternatively, phthalic acid can be obtained by the hydrolysis of certain plastics.
Lastly, xylene can be oxidized to phthalate, but OTC xylene is a mixture of isomers, and you'd end up with a mixture of phthalic, isophthalic and
terephthalic acids.
https://en.wikipedia.org/wiki/Phthalic_acid
https://www.sciencemadness.org/talk/viewthread.php?tid=15920...
https://www.sciencemadness.org/talk/viewthread.php?tid=15557...
https://www.sciencemadness.org/whisper/viewthread.php?tid=65...
https://www.sciencemadness.org/whisper/viewthread.php?tid=87...
https://www.sciencemadness.org/whisper/viewthread.php?tid=17...
"However beautiful the strategy, you should occasionally look at the results." -Winston Churchill
"I weep at the sight of flaming acetic anhydride." -@Madscientist
"...the elements shall melt with fervent heat..." -2 Peter 3:10
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Mister Double U
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chempyre235,
You convinced me, it seems that Phthalic Anhydride can be made by the amateur.
In general, I think these would be the required steps/questions to answer to get this to work:
1. Synthesis of Phthalic Anhydride
2. Purification of Phthalic Anhydride
3. Synthesis of Phthalocyanine-metal complex
4. Purification of Phthalocyanine-metal complex
5. Deployment of Phthalocyanine as an electrocatalyst (homogeneous or heterogeneous)
6. Choice of suitable electrolyte
7. Choice of electrode materials
8. Type of cell (divided/undivided)
9. Choice of process parameters (Current density, temperature, stirring, concentrations)
10. Dispersion method for Oxygen dissolution into the electrolyte
11. Recovery of product (extraction, distillation, crystallization)
And there are probably more things to think about...
Anyway, I do not want to rain on the parade, but I am trying to get the persulfate route to work. It would be nice, if someone could offer any help
with that.
At the moment, I am the only person in this thread running experiments. Comments of the type "you should do this <halfway thought through idea>
not that" do not really help IMHO. This is not meant to be taken personally - I just have seen many of these types of comments lately on the forum. In
the end, I think the fun is in doing the chemistry not just talking about it :-D
If you think your proposed process has great potential, why don't you give it a try? I would like to see you succeed!
[Edited on 8-9-2025 by Mister Double U]
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chempyre235
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| Quote: Originally posted by Mister Double U | chempyre235,
You convinced me, it seems that Phthalic Anhydride can be made by the amateur.
In general, I think these would be the required steps/questions to answer to get this to work:
1. Synthesis of Phthalic Anhydride
2. Purification of Phthalic Anhydride
3. Synthesis of Phthalocyanine-metal complex
4. Purification of Phthalocyanine-metal complex
5. Deployment of Phthalocyanine as an electrocatalyst (homogen or heterogene)
6. Choice of suitable electrolyte
7. Choice of electrode materials
8. Type of cell (divided/undivided)
9. Choice of process parameters (Current density, temperature, stirring, concentrations)
10. Dispersion method for Oxygen dissolution into the electrolyte
11. Recovery of product (extraction, distillation, crystallization)
And there are probably more things to think about...
Anyway, I do not want to rain on the parade, but I am trying to get the persulfate route to work. It would be nice, if someone could offer any help
with that.
At the moment, I am the only person in this thread running experiments. Comments of the type "you should do this <halfway thought through idea>
not that" do not really help IMHO.
On the other hand, if you think your proposed process has great potential, why don't you give it a try? I would like to see you succeed!
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No, I get it. You've been doing excellent work and have made much headway on the persulfate process. The phthalocyanine process is a whole other
animal. Great job sticking to this project! You have the persistence of @semiconductive, who had been working on nickel plating solutions.
Unfortunately, I don't have any kind of laboratory at the moment and so am bound to perform my chemical projects vicariously for the time being. I
intend to make phthalocyanine in the future for its electrochromic properties, but it won't be for a while yet. 
[Edited on 9/8/2025 by chempyre235]
"However beautiful the strategy, you should occasionally look at the results." -Winston Churchill
"I weep at the sight of flaming acetic anhydride." -@Madscientist
"...the elements shall melt with fervent heat..." -2 Peter 3:10
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Mister Double U
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I apologize for being grouchy, chempyre235.
It's probably my frustration that I have not made better progress with this.
In addition, I hope you will have some lab space available to you soon - so you can have some fun.
Regarding the Phthalocyanine, it would be cool if it could form Perchlorate/Nitrate salts for energetic purposes. I read on Wikipedia it can be
protonated, but this is a different topic...
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