plante1999
International Hazard
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Registered: 27-12-2010
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Persulphates salt preparation
I finnaly got a platinum anode but my attempt to make persulphates salt are not very succefull at the time, I'm looking for synthesis procedure and
help from people that have alredy made some but every type of help is apprecied. The major probleme is that I have sodium bisulphate but not the
potassium salt, I have conc sulphuric acid.
The two salt that I have the precursor are:
Peroxydisulphuric acid
Sodium peroxydisulphate
Edit: Electrolysis of 35% sulphuric for few hour give me a slow response for oxidizer with iodide starch paper
At start the paper was white, and after 3 minutes the paper turned dark black.
Thanks!
[Edited on 13-7-2012 by plante1999]
[Edited on 13-7-2012 by plante1999]
I never asked for this.
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plante1999
International Hazard
Posts: 1936
Registered: 27-12-2010
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I tough I may be a good Idea to report My experimatation with a platinum anode here so:
General set up:
Anode: Pt 1 square cm
Cathode: tiny Ti wire 0.25 square cm
Cell electrolyte volume: 25-30ml
Amperage: the voltage is changed constantly to get 0.5amp
Voltage:3-6V
Temperature: 20 degree C but when specified 10 degree
Persulphates ( 4 V approx):
For the peroxydisulphuric acid, The concentration did not seam to go up, probably because the acid is somewhat prone to decomposition.
(10 degree Celsius electrolyte)I tried to make sodium peroxysulphate using sodium bisulphate solution, after one hour of 0.5 amp electrolysis there
was a fast response to iodide starch paper. I had already read that dichromate can help to reduse the reduction of the peroxydisulphate at the cathode
so I added 0.01g of ammonium dichromate in the electrolite and immediatly the gas production at the cathode increased a lot. The gas production at the
anode was steady, The amperage lowered of 0.04 amp. The solution was kept in a container for tomorrow and real peroxides were tested.
Real peroxide salts:
Sodium Perborate:
(10 degree Celsius electrolyte)A solution of 12g of sodium carbonate and 4.5g of borax was made and tapped to 100ml of solution. The solution was
electrolised for 20 minutes, then a test with Titanium III chloride(You may know that I do titanium chemistry and I have ready 100ml of fresh (max 6
month old) 20% sol.) was made and was proved very positive. A similar test was made with 3% H2O2 and was proved about as much positive.
More test soon!
I never asked for this.
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plante1999
International Hazard
Posts: 1936
Registered: 27-12-2010
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Mood: Mad as a hatter
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Sorry for the triple post but I tough it could be interesting to describe my experimentation.
I continued the electrolysis for perborate over night (the ice bath melted and the temperature probably increased to 20 degree c) but when I tested
for peroxide with the titanium III solution the test was less positive than after 20 minutes, so I suspected back reduction at the cathode. I added
dichromate to reduce reduction at the cathode, put ice bath again and started the electrolysis for 2 hours, After the time the solution made bubble
(suspected decomposition of the peroxide) and a bubbling precipitate was on the bottom (probably perborate). Ice bath was filled up again and the
electrolysis continue.
Question:
How can I stabilize hydrogen peroxide?
Thanks!
I never asked for this.
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symboom
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Mood: Doing science while it is still legal since 2010
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I know the answer stabilization of hydrogen peroxide is with phosphoric acid
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