pokerhelper
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Vacuum Distillation of H2O2
Hi,
I am attempting to distill some 90+ percent hydrogen peroxide.
I will be as safe as possible (shields, small quantities, etc)
Does anyone know the boiling points of h202 at different pressures?
I will be starting with 35%, which has a BP of 150 C at 1 atm...
As the concentration rises, the combustion temp drops to
~ 80 C... (hence the need for the vacuum)
Does anyone know where to purchase a reasonably priced vacuum distillation setup, preferably used?
Im in the market for one, if someone has some equipment they want to sell.
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_1v4_
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This link might be interesting to you (it's got pretty much stuff about H2O2):
http://www.h2o2.com/intro/properties.html
And here you have sth about boiling points and pressures:
http://www.h2o2.com/intro/properties/physical.html#10 (take a look at 13.)
Hope it helped...
[Edited on 14-11-2006 by _1v4_]
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pokerhelper
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Thank you so much 
That helps a lot.
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Eclectic
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A rotovap works fairly well to concentrate H2O2 from 30% up to >90%. You remove the excess H2O and leave the stabilizers.
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Tsjerk
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| Quote: | | A rotovap works fairly well to concentrate H2O2 from 30% up to >90%. You remove the excess H2O and leave the stabilizers. |
Wich stabilizers do you mean? I presume you mean this happens when they are present. As far as I know in most types of H2O2 there aren't any.
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Maya
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Why don't you freeze it instead?
Fractional crystallization will give you pretty pure hydrogen peroxide way easier
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Jdurg
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| Quote: | Originally posted by Tsjerk
| Quote: | | A rotovap works fairly well to concentrate H2O2 from 30% up to >90%. You remove the excess H2O and leave the stabilizers. |
Wich stabilizers do you mean? I presume you mean this happens when they are present. As far as I know in most types of H2O2 there aren't any.
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In all forms of OTC H2O2 there are stabilizers present to increase shelf-life of the product. With most lab chemicals there shouldn't be a great
number of stabilizers in there, I believe.
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Drunkguy
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What do you mean shields? I know acetone peroxide etc are explosive but I hadent realised that H2O2 was an issue.
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Eclectic
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The stabilizers are usually phosphoric acid or tin compounds. Leaving them in the concentrated H2O2 is a GOOD thing.
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Blind Angel
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| Quote: | Originally posted by Drunkguy
What do you mean shields? I know acetone peroxide etc are explosive but I hadent realised that H2O2 was an issue. |
Well considering that it is rocket fuel at this concentration and that it decompose readily on contact of most metal to form H2+O2 which ignite on the
spot, it can become an issue.
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Waffles
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| Quote: | Originally posted by Maya
Why don't you freeze it instead?
Fractional crystallization will give you pretty pure hydrogen peroxide way easier |
There are threads on freezing to concentrate. If I remember correctly, it only works up to a certain concentration effectively.
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Axt
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Extract from PATR2700 H219:
<i>Explosive and Combustion Props</i>: Pure H2O2 is readily detonable and its heat of expln is given as 24.6 kcal/mole. It is claimed that
aq solns of less than 94% H202 will decomp explosively if catalyzed, but will not detonate (Ref 4). More recent studies, however, show that 86% H202,
at 50° or higher and contained in 1.61 inch ID Al tubes, will detonate at 5600 m/see when strongly boostered, but not at smaller diameters. A 90.7%
soln detonates at ‘5500 to 6000 m/sec even at 0.5 inch ID and 25°. The gap over which the 90.7% soln will propagate detonation increases with
increasing temp (Ref 23).
Mixtures of (H202)gas/air will not detonate at subatmospheric press. However, a 35 mol% mixt will detonate at 6700 ft/sec at 1 atm. The ignition’
limit under these conditions is about 30 mol% H202 vapor (Ref 21)
[Edited on 14-11-2006 by Axt]
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unionised
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it decompose readily on contact of most metal to form H2+O2
Oh Yeah?
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Blind Angel
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I stand corrected thank you, but I had a part of the truth.
From Wikipedia:
Use as a monopropellant takes advantage of the decomposition of 70–98+% concentration hydrogen peroxide into steam and oxygen. The propellant is
pumped into a reaction chamber where a catalyst (usually a silver or platinum screen) triggers decomposition, and the hot (>600 °C) oxygen/steam
produced is used directly for thrust.
Hmm, it doesn't ignite sorry and I shouldn't have said readily with most metal you're right, but I think that most metal though will help the
decomposition at a certain point, some more than other, and some more violently.
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pokerhelper
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What a great idea, ty
I could make an alcohol bath with some dry ice...
and freeze out the water.
That would be a great initial step, to be followed by distillation if necessary.
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unionised
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"Hmm, it doesn't ignite sorry and I shouldn't have said readily with most metal you're right, but I think that most metal though will help the
decomposition at a certain point, some more than other, and some more violently. "
More importantly, it doesn't form hydrogen (to speak of).
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Maya
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Like I said freeze it out to obtain pure crystals
look it up in Brauers preparative inorganic chemistry 1963
this has also been hashed B4
http://www.sciencemadness.org/talk/viewthread.php?tid=399
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