m1tanker78
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How to stabilize freshly prepared H2O2?
First, let me say that the method I'm using to prepare it is with sodium peroxide. I usually cheat a little bit and ignite the Na with a propane torch
while holding it in a gentle stream of O2 from my oxy/acetylene gear. This greatly increases the yield of Na2O2 over Na2O. I can only burn small
quantities of Na at a time since it quickly forms a puddle of goop if left standing in air even for a few minutes. I slowly add minute quantities of
the resulting Na2O2/Na2O to distilled water. This releases quite a bit of energy but not enough to significantly heat the solution if done a little at
a time. The resulting solution consists of H20, H2O2, and NaOH which makes it strongly alkaline. I've tried neutralizing the solution with HCL and
even using a slight excess to make the solution slightly acidic. I observe O2 bubbles forming in the container and bubbling out for 3 to 5 days
afterward. I can't seal the container due to dangerous pressure buildup.
I'm not after HTP; especially if it has any degree of instability. I'd like to prepare small quantities of ~20 - 30% H2O2 with an intended shelf life
of no more than 3 or 4 months. 500mL 30% H2O2 can be had at the local pharmacy with a Dr.'s prescription at the 'modest' price of $117.xx USD plus
tax, handling, and who knows what other surcharges. Not exactly cheap!
So what can I use to stabilize this freshly prepared H2O2 and make it safe for general use after diluting? I've read that certain metals such as
copper catalize the decomposition. Would H2SO4 be a better acid for neutralization?
Tom
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Mixell
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Strange, H2O2 isn't very expensive, you sure you can't find some chemical store or who knows what?
In Israel a liter of H2O2 (33%)costs about 6$ and its a bit cheaper than 1l of concentrated sulfuric acid, 117$ for 500 ml is more than crazy...
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MrHomeScientist
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There's a certain pool chemical that's called "Baquacil Oxidizer," touted as a chlorine-free pool alternative, that is 27% H2O2 that is
"specially-stabilized." That's a relatively cheap alternative to making it yourself as well.
I don't really have any information as to your original question, but maybe this stuff has an MSDS that lists what that stabilizer is and that might
help you out.
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hissingnoise
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| Quote: | | In Israel a liter of H2O2 (33%)costs about 6$ . . . |
Strange, I thought Israel would make it harder to get HTP than elsewhere?
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madscientist
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Phosphoric acid is a common stabilizer. But be careful your source is clean. It's frequently contaminated with iron cations, which catalyze the
decomposition of hydrogen peroxide - quite spectacularly.
I weep at the sight of flaming acetic anhydride.
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Mixell
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Well, you can't get it at any store, but there are chemical stores that sell bulk quantities (1 kg/1 L or more) but very good prices.
And HTP (if your mean high test peroxide) is 80%+ , this concentration is of-course not for sale for ordinary citizens.
33% is the highest I've ever seen for sale here, but 50% or more might be found somewhere, just need to ask.
You can also get nitrate salts at a lot of other stuff (basically any chemical) if the quantity you purchase does not exceed 1-2 kilograms (except any
highly poisonous substances probably) without having a special permit (mostly regarding the disposal of any byproducts and such).
Just too bad the store is 2h away by bus (and 20 minutes by foot)...
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hissingnoise
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Is that small buses or big feet . . . ? 
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phlogiston
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8-Hydroxyquinoline was used as the stabilizer in the HTP used as a propellant in the German Me-163 plane during WO II
Wikipedia lists number of common uses for this stuff (and google finds a few more).
It is a chelator, so perhap other chelators may also work. However, you may want to verify that whatever chelator you decide to use/try is itself
stable in hydrogen peroxide, at least for the period you want to store it for.
[Edited on 7-3-2011 by phlogiston]
[Edited on 7-3-2011 by phlogiston]
-----
"If a rocket goes up, who cares where it comes down, that's not my concern said Wernher von Braun" - Tom Lehrer |
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Mixell
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Good one =)
But unfortunately its an additional 20 minutes by foot, and having a 20 kg box with chemicals to carry all that way is not so fun...
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bahamuth
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Glycerol is a common stabilizer for hydrogen peroxide, though I do not know in what concentration..
Any sufficiently advanced technology is indistinguishable from magic.
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m1tanker78
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Mixell, the only OTC H2O2 available here is 3%. The highest concentration I can achieve from 3% is 15% by freeze fractioning. 4 liters of 3% takes 3
to 5 days to extract around 50 mL max of concentrated H2O2. It ties up 2 or 3 shelves in my freezer and needs tending to throughout the day. It works
but the yield is very low for a given batch.
MHS, I appreciate the lead. I'll definitely check the MSDS but have a feeling I'll come across the same vagueness as with other peroxide products.
HN: I found a couple of websites that reference the use of methylene to stabilize H2O2. One mentions the use of an acid-peroxide feedstock but is used
for temperature stability. Their H2O2 feed is presumably already stabilized for storage.
| Quote: | | Phosphoric acid is a common stabilizer. But be careful your source is clean. It's frequently contaminated with iron cations, which catalyze the
decomposition of hydrogen peroxide - quite spectacularly. |
Maybe my problem is that the HCL I used to neutralize the NaOH contains some iron impurity. I wonder about using naval jelly or similar rust remover.
I'm sure they contain a substantial amount of iron cations, though.
Tom
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m1tanker78
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http://www.using-hydrogen-peroxide.com/hydrogen-peroxide-gel...
I found this site which gives a recipe for 'sticky' peroxide gel with glycerol (sold as "glycerine" here).
http://books.google.com/books?id=C4Cr8dHupVsC&pg=PA272&a...
This book describes glycerine as "highly explosive" with hydrogen peroxide. I guess it makes sense if it's heated to the decomp point of the peroxide.
The scary thing is that my peroxide is decomposing at RT.
Iron chelator(s) sound promising....
Tom
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S.C. Wack
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A little sodium phosphate, with phosphoric acid for acidity, is standard in industry.
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hissingnoise
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Biostain, a UK company sells 35% H<sub>2</sub>O<sub>2</sub> through ebay.
Shipping shouldn't be too bad on 500ml!
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m1tanker78
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I diluted some of my freeze-fractioned 15% peroxide down to around 5% and added twice the volume of glicerin. This was for skin application - it
worked well although the oily feeling is a little strange. I wouldn't want to mix large batches of it though. I might redo my experiment using
glicerin and see what happens. If I can get my hands on some phosphoric acid then I'll obviously try that too.
HN: I'm going to write that company and see how much the shipping would come out to. They have a 2kg limit for regular post which takes 2-5 weeks to
arrive. I'm not sure if US customs would make a stink about it....
Tom
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gregxy
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There are lots of people selling it on Ebay 17% to 35%
and without hazmat fee (as far as I can tell).
They seem to think it is a good way to get oxygen into
your body.
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Tiberius_C
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Locally, you might want to try a brewing supply store -- 30% H2O2 is sometimes used in brewing to sterilise equipment. No toxic residues get left in
the suds.
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m1tanker78
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I came across a few references to stabilizers while doing some related searches. They aren't specifically used for H2O2 from Na2O2 but should still
apply here.
The two stabilizers specifically mentioned are magnesium sulfate and sodium silicate.
H2O2 is often times used in the pulp and paper industry for its bleaching effect. The only caveat is that the peroxide is expected to remain effective
in an alkaline bath that invariably contains metal ions that catalyze the decomposition of the peroxide. What I gathered was that the sulfate serves
to chelate(?) the metal ions and the silicate serves to buffer the bath's pH. There's no mention of the concentration of either.
I think an experiment or three is in order. Maybe 4 samples; one prepared the
way I normally do, a second with an arbitrary concentration of MgSO4, a third with an arbitrary concentration of sodium silicate and a fourth with a
blend of both. I'm not sure about the silicate - the only silicate I have at the moment is contaminated with iron (I think).
What do you all think would be a good starting ratio of water to MgSO4.? Should I continue using hydrochloric acid for neutralization or should I use
sulfuric?
Tom
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ScienceHideout
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Quote: Originally posted by Mixell  | Strange, H2O2 isn't very expensive, you sure you can't find some chemical store or who knows what?
In Israel a liter of H2O2 (33%)costs about 6$ and its a bit cheaper than 1l of concentrated sulfuric acid, 117$ for 500 ml is more than crazy...
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I wish I lived in Israel. Land of God, cool president (or prime minister?) and now 33% H2O2? Is that even legal in America?
When my grandma gets hair care supplies I go with her to buy "Clairoxide". 40 vol is equal to 9% or 12% (I think 9). It is good enough for most lab
purposes for me.
[Edited on 15-3-2011 by ScienceHideout]
hey, if you are reading this, I can't U2U, but you are always welcome to send me an email!
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m1tanker78
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Ahem, since we're on the topic of Israel.....
Years ago, my unit got deployed halfway 'round the world to serve in a multi-national NATO mission. Among all the foreign troops I worked with, the
Israelis I'll always remember. Their dedication, experience and professionalism made them a force to be reckoned with. On top of that, I almost
crapped my pants when I saw female Israeli tankers and learned that even combat arms units are 100% co-ed. I was an M1 Abrams Tank Crewman (tanker) in
the US Army and never imagined I'd see a female crew in one of those beasts. In spite of the bad press they receive sometimes, I tip my hat to the
Israeli Army!
Tom
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UnintentionalChaos
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Yes, have you never heard of baquacil? Also, 35% can be had from delusional alternative medicine suppliers.
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
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ScienceSquirrel
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35% hydrogen peroxide can be obtained quite readily in most places.
I dilute it and use it to wash out my fermenters, kills everything and can be left to drain dry with no residues.
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Mixell
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Be happy that you don't live in Israel, there are many reasons for it, if you wish I could explain further, but this is not the place (Looking for
access to the whimpsy section by the way).
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m1tanker78
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I took advantage of some Na scraps I had left over and made another attempt at this. I dissolved ~1 teaspoon of MgSO4 (sorry, still no sensitive
scale) in 250mL of distilled water. This is quite a bit more water than I used before; I figured this should help buffer the exothermic reaction a
little better. The water was chilled to around 4C as before. I honestly can't put an exact quantity on the sodium peroxide because I still lack a
suitable scale and because some sodium oxide is inevitably also produced. I'll estimate the total of Na2O2 and Na2O at around 150 mg. Indeed, this was
a quickie; didn't want to burn more sodium if it wasn't going to work out.
I added the peroxide a little at a time and as expected, an exothermic reaction ensued. I didn't observe any bubbling at all afterward. I neutralized
the caustic solution (~pH 10.5) with some hydrochloric acid. It was dead neutral so I allowed the liquid to sit overnight at RT - lightly capped to
allow gas to escape if needed. I have yet to see any bubbles at all except when the liquid comes in contact with MnO2. From my observation (not from
volumetric testing), the concentration of H2O2 is well under 1% but dead stable. That's my cue to try a higher concentration next.
This quick and dirty experiment left me with a question. Each time I added the peroxide/oxide, I saw a white precipitate form both on the surface and
at the bottom of the liquid. I'm pretty sure the bottom precipitate was hydroxide but what about the surface? The appearance was like a cotton ball
that's been pulled apart and pretty quickly dissolved on its own (no agitation). I assume it was sodium sulfate??
Tom
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