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Hydrogen Peroxide purification
I recently found H2O2 which is available for bleaching hair, but it's written that it's oil based 12% H2O2. I checked and I remember it contained some
smell additives and some others to form an emulsion.
Now, could I use it like that or is there a way to purify it without distillation? Or maybe I could purify the resulting products when I would react
it with something.
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Bot0nist
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Why not just buy the 3% variety? Its already relatively pure and stabilized. I pour 600ml of it in a beaker and heat it on my electric stove top on
the '3' setting. After 6 hours or so its down to 100ml and the maximum surface temperature never exceeded around 170F, so I think losses were pretty
low. I have never titrated this, so I'm not sure what % I actually ended up with, but it will leave nasty white blisters on your skin if your not
careful so I imagine its around %15.
This method is easy and uses commonly available H<sub>2</sub>O<sub>2</sub> solutions found in most stores. It works perfectly
for oxidizing iodine or bromine ions, or for organic peroxide synthesis, so why go through the trouble of extracting it from goopie hair bleach?
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Well, 3% is a lot more expensive than that 12% variety and thinking about buying 97% water doesn't help either.
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Bot0nist
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I'm in the U.S. and at walmart its $0.97 for 950ml of 3%. That's pretty cheap, and that 97% of water is a lot easier to get rid of that the 88% crap
in that hair dye I'm betting.
Or you could buy it online.
<a href="http://www.dfwx.com/goewebsite.htm?gclid=CIed2unV76cCFYnd4Aod0g2DaQ">H<sub>2</sub>O<sub>2</sub></a>
<a
href="http://www.rebekahspureliving.com/hydrogen-peroxide/food-grade-peroxide?gclid=CM_Zuo3W76cCFQbe4Aodg1AJbQ">H<sub>2</sub>O<sub&g
t;2</sub></a>
<a
href="http://www.google.com/products/catalog?hl=en&rlz=&q=h2o2&um=1&biw=1600&bih=707&bav=on.2,or.r_gc.r_pw.&ie=UTF-8&c
id=16248559769594682236&sa=X&ei=i6mPTc_CFMe_gQf3p9C_DQ&ved=0CFoQ8wIwAQ#">H<sub>2</sub>O<sub>2</sub></a>
[Edited on 27-3-2011 by Bot0nist]
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hkparker
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Ive used Guardian Of Eden before. They get very mixed reviews so I wouldn't try from there first but I had a good experience with them.
My YouTube Channel
"Nothing is too wonderful to be true if it be consistent with the laws of nature." -Michael Faraday
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ScienceSquirrel
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Hydrogen peroxide of around 30 - 40% concentration is readily available in most jurisdictions.
It has applications in food preparation, etc and is sold to believers in oxygen therapy.
It is very cheap at around £10 - 15 for 500ml and it is a lot cheaper if you buy larger quantities in the UK.
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m1tanker78
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Can you post a list of ingredients? This may help to determine how to go about purification.
Botonist is right about 3% H2O2 being dirt cheap at walmart. However, boiling off the water or even warming it will cause most of the H2O2 to
decompose. The maximum concentration you can achieve by this method is 4.5% under reasonable circumstances so it's a waste of time and energy.
You can pull a vacuum on 3% and heat it gently. I've obtained ~17% by this method but it takes a very long time and again, it's very wasteful of
energy. Also, the higher concentrations tend to decompose much quicker and this method is said to be an explosion risk. That's why I never tried going
higher.
You can buy a few of the 3% wal-mart 950mL bottles and purify it by the freeze method to ~15% concentration. It takes a while but yields very clean
H2O2 solution and isn't terribly labor-intensive. If you have space in your freezer, then the hard part is done.
If you're interested, I can post up the freeze method that works well for me, given the circumstances.
Tom
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Bot0nist
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Quote: Originally posted by m1tanker78  | Can you post a list of ingredients? This may help to determine how to go about purification.
Botonist is right about 3% H2O2 being dirt cheap at walmart. However, boiling off the water or even warming it will cause most of the H2O2 to
decompose. The maximum concentration you can achieve by this method is 4.5% under reasonable circumstances so it's a waste of time and energy.
Tom
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I am sure that the peroxide in my fridge right now is > 4.5%. Cold, 4.5% hydrogen peroxide will not bleach and blister the finger tips,
and I just heated it in the manner described above.
The slow, gentle heating will reduce some of the H<sub>2</sub>O<sub>2</sub>, but the losses will not be as catastrophic as
m1tanker78 claims. Many members on this site use the heating method with success. Just check one of the many threads on organic peroxides and hydrogen
peroxide.
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m1tanker78
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| Quote: Originally posted by Bot0nist | | Quote: Originally posted by m1tanker78 | Can you post a list of ingredients? This may help to determine how to go about purification.
Botonist is right about 3% H2O2 being dirt cheap at walmart. However, boiling off the water or even warming it will cause most of the H2O2 to
decompose. The maximum concentration you can achieve by this method is 4.5% under reasonable circumstances so it's a waste of time and energy.
Tom
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I am sure that the peroxide in my fridge right now is > 4.5%. Cold, 4.5% hydrogen peroxide will not bleach and blister the finger tips,
and I just heated it in the manner described above.
The slow, gentle heating will reduce some of the H<sub>2</sub>O<sub>2</sub>, but the losses will not be as catastrophic as
m1tanker78 claims. Many members on this site use the heating method with success. Just check one of the many threads on organic peroxides and hydrogen
peroxide. |
Botonist, it doesn't take much to blister the skin or to feel the pin pricks. Before I built my volumetric aparatus, I used to test H2O2 strength on
my fingers (ouch). 15% will blister, prick, and bleach the skin pigment found in the dermis. Pigment returns after a few days.
In my experience, heating a 3% solution on the stove only ever yielded 4.x% Post your method and perform a volumetric test on its decomposition with
MnO2. Maybe you're doing something I'm not.
Bottom line: If it works well for you, use it!
Tom
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Bot0nist
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I believe what I am yielding is around the 12-15% mark based purely on the effects of accidental skin contact (Itchy burning feeling followed by white
blisters). I have never done a volumetric test to determine the amount of oxygen liberated, though that would be useful to know and would prove that
gentle heating is a viable method to concentrate H<sub>2</sub>O<sub>2</sub>.
My method is as follows.
500ml of cold,stabilized, 3% H<sub>2</sub>O<sub>2</sub> is poured into a 1000ml beaker. Said beaker is placed on an electric
coil range. The range is then turned on to the #3 setting. A piece of plastic tubing attached to an aquarium air pump is directed as to blow a gentle
stream of air into the mouth of the beaker to aid evaporation. Slight steaming can be noticed about 10 minutes into the heating. Using a temp gun, the
surface temperature was steady around 150F at the beginning, and then as the solution grew in concentration, the temperature stabilized at around
170F. No boiling or simmering is ever observed. Only a gentle steaming. When the solution has reduced in volume to around 100ml it is removed from the
burner and poured into a dark HDPE container, which is then placed in the fridge.
I theorize that by using a large Pyrex casserole dish in an oven heated to 150F, one could speed this process up due to the increased surface area,
dry air in the oven, and over all convective heating, as opposed to the conductive heating of the bottom of the beaker, which could cause hot spots
and increase the rate of decomposition.
I have successfully synthesized M.E.K.P. using this H<sub>2</sub>O<sub>2</sub> by adjusting my
H<sub>2</sub>O<sub>2</sub> proportion to the 15% concentration, and increased my acid to accommodate the extra water in the
solution. I reliably get yields that are comparably to a synthesis that uses 30% H<sub>2</sub>O<sub>2</sub>. I realize this is
not as definitive as volumetricly measuring the gases evolved from decomposition though. If time permits this week I will try to get some empirical
results on the concentrations I obtain via gentle heating.
[Edited on 28-3-2011 by Bot0nist]
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m1tanker78
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Botonist, I'm going to dust off my notes and refresh my memory. I remember trying something similar with a stream of ozonized air. That was the only
source of constant, gentle air I had at the time - had nothing to do with O3. I honestly don't remember how that one turned out or if I even kept it
going.
Post up the results of your volumetric test(s) if you end up doing them. It would be interesting to compare results and maybe find a better way.
Tom
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Bot0nist
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I will get some results for you this week. I have to get a proper catalyst for the decomposition. Maybe some old batteries.
I have read that aspirating H<sub>2</sub>O<sub>2</sub> with warm, dry air works. Maybe if I can rig up an air dryer and
aspirator with a suitable filter to reduce possible contaminates I will try that and compare.
I am thinking that once I get a proper volumetric apparatus built this week I will try to compare heating, aspirating, and freezing methods to see
what can give the highest concentration. Maybe a combination of freezing first to get approx. 12-15% and then aspirating with dry air while gently
heating.
Looks like I need to stop by wally world for copious amounts of H<sub>2</sub>O<sub>2</sub> again. 
EDIT: I guess it seems kind of pointless to go through so much trouble as hydrogen peroxide can be bought at 30% most places, and if one can go
through the trouble of rigging a dry-air aspirator then they can surely get a simple vacuum distillation going. I will still try and do the experiment
out of curiosity, and out of the fact that my only means of current vacuum is a little hand-help pump meant for vacuum filtering.
[Edited on 28-3-2011 by Bot0nist]
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m1tanker78
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Unwashed battery crud works fine. I made my apparatus to where I carefully load some MnO2 crud in a tube, load the container with my unknown H2O2
solution, secure the cap and give it a tap or shake to release the MnO2 and kick off the decomp. I epoxied a brass connector on the cap for the gas
outlet. It worked well but I suppose you probably have more professional gear at your disposal.
| Quote: | | Looks like I need to stop by wally world for copious amounts of H2O2 again. |
I've gotten a few funny looks at wally world when I roll up to the register with 8 bottles of peroxide and 6 cans of salt.
One cashier flat out asked me, "What's all that for?" Rather than responding that it's none of her F'n business, I told her it's needed for a
therapeutic soak in the bathtub. I'll bet she bought a couple of bottles of peroxide and a can of salt after her shift ended.
There are a couple of other experiments I wanted to try. One with calcium chloride and another with a centrifuge that I haven't gotten around to
building. I'm also doing some experiments with sodium peroxide.
Tom
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DerAlte
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Freeze concentration of 3% H2O2
http://www.sciencemadness.org/scipics/H2OH2O2-solid-liquid-p...
Nothing new here except a possible improvement in technique. I had obtained a couple of liters of cheap 3% peroxide recently, intending to oxidize
Cr+++ ions to chromate and dichromate. I decided to freeze concentrate to around 25-30% to reduce water burden and speed things up. Looking at the
above phase diagram (from US Peroxide’s web site) a domestic freezer should do the job.
1 L 3% contains 970 g H20 and 30g H2O2 which should give 70g water and 30 g H2O2 at 30%; the rest (900 g) will be ice to be separated.
The separation can be done on a plastic sieve (best not to use metal but SS might be OK if clean). However the problem of separating 900 g solid from
the 100g liquid is that the liquid clings to the ice and yield is not too good. I adopted the following technique:
Do it in stages, say to 10%, 20%, and then near 30%. Use a clear clean glass jar – cleanliness is next to godliness with H2O2 – with a lid in
which a thermometer is placed. Let the liquid cool to -7C in the freezer or thereabouts – or just visually inspect for when a modest amount of ice
is formed. For low % the ice forms on the walls of the jar. The liquid at 10% will weigh about 300 g; the ice will be around 700g. Dislodge the ice
and pour all into the sieve. Let the ice warm up to 0C when it will commence melting and in doing so wash off the 10% solution adhering to the ice
into the vessel below the sieve. This ensures that most of the H2O2 is preserved in the liquid and minimizes loss. (Put the remaining ice aside
for titration with KMnO4 if desired to see H2O2 content).
You now have perhaps 350 g of liquid containing ideally 30 g H2O2, 7.9% by weight.
Repeat the process allowing the temperature of the liquid to drop to about -15C this time for around 20% w/w solution, weight = 150g liquid and 200 g
ice. Next time round freeze the hell out of it and you should be near 30% in the liquid phase. This method can be reduced to 2 stages with a Buchner
funnel or fritted glass plate plus suction with very little loss of H2O2.
30% H2O2 is quite reactive and will irritate the skin and turn it white temporarily. Take care! Any spills should be diluted and carefully wiped up.
The peroxide can evaporate further and set fire to a cloth soaked in it.
Attempts to further concentrate by evaporation under reduced pressure (say 20mmHg) keeping temp <45C can yield much higher % but for inorganic use
30% is strong enough. Only an expert should exceed 30%, IMHO.
The same process can be worked for many mutually soluble liquids – eg weak ethanol to ~35% or sulphuric acid to ~25%. Of course any dissolved
impurity tends to concentrate too. (Used stabilizer is typically acetanilide or sodium pyrophosphate, 25-125 mg/L)
Der Alte
[Edited on 29-10-2011 by DerAlte]
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