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DerAlte
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Déjà vu all over again
It is perhaps inevitable in a long running forum like SM that the same old topic gets repeated time and time again, ad nauseam and to the nth degree.
This is one of them. UTSE
Concentration by freezing is covered in
http://www.sciencemadness.org/talk/viewthread.php?tid=15881#...
(this will get you to 25-30% in a domestic refrigerator, and maybe 45% using a dry ice refrigerant. Past that you’ll get the eutectic).
For considerable info re H2O2 see
http://www.h2o2.com/technical-library/default.aspx?pid=9&...
The method suggested by Planté also works. However, it is rather tedious and takes a long time. The partial vapor pressure of H2O2 is considerably
less than water. See the reference above.
I would emphasize the warning given by Science Squirrel about over concentration. And don’t mess about with organics either. Scrupulous avoidance of
any heavy metal ions is essential for the stability of H2O2 solutions. Remember that on concentration by the above methods you also concentrate
whatever stabilizer the manufacturer has added..
Der Alte
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Glucose Oxidase
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APO if you want a high concentration hydrogen peroxide try to produce BaO2 and then treat it with sulfuric acid it should give a yield close to 90%
percent
PS: i never tried this myself so dont ask me about details i just digged it up from the internet.
PS2:BaO2 can be produced (as far as i remember) by heating BaO to 700C or something good luck.
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plante1999
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It is 500 to 600. You can only make 3-6% peroxide with barium peroxide by my work. You don't have tried it, it is evident.
I never asked for this.
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platedish29
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SS from your link to wikie's:
"High-concentration hydrogen peroxide was formerly available in 70, 90, and 98% concentrations in sizes of 1-gallon, 30-gallon, and bulk-tanker truck
volumes, but is now no longer available to the public in the United States due to action by the Department of Homeland Security."
How?
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shannon dove
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Quote: Originally posted by platedish29  | SS from your link to wikie's:
"High-concentration hydrogen peroxide was formerly available in 70, 90, and 98% concentrations in sizes of 1-gallon, 30-gallon, and bulk-tanker truck
volumes, but is now no longer available to the public in the United States due to action by the Department of Homeland Security."
How? |
I don't think I would like to be riding next to a tanker truck full of 98% hydrogen peroxide.
Would that be a yellow and an orange placard?
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Poppy
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Haven't witnessed H2O2 in high concentrations b4, but cmon, if vapors are scary then you need some fans..
Gasoline is sickly scary even when like 50cc are poured around, and even NG wont explode on shock that easily mostly in water.
so that 2% water should be ok to save your life?
Don't think so.
But after wathing youtube's video on Cl2O I feel something bad about all this.
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mayko
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| Quote: Originally posted by plante1999 | | Quote: Originally posted by kristofvagyok | Gas volumetric titrations are not the best, they have a high percent failure rate. Titrate it with KMnO4.
You've said that you can go up with this method to 50-90% H2O2 content, you also wrote that you have started from 3% H2O2 and got 100cm3 of +90% H2O2
what is everything but not true.
So what did you get from what? If you have ended up with 30% H2O2, than it's aint special, anyone can buy it and also everyone can make it.
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I will try to do something for titration, as permanganate is regulated here, and as you may know, not everybody here have the mean and the resource of
a commercial lab as you do.
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I've seen a number of guides to concentrating peroxide, but analyzing it has generally been treated qualitatively. I have generally done this by
determining the density of the solution, and working backwards from that. This has the advantage that it only requires tools for accurately measuring
mass and volume, which would hopefully be available even to a DIY lab. Here's a walkthrough:
http://topologicoceans.wordpress.com/2013/01/30/lablulz-densitometry-of-hydrogen-purr-oxide/
I've since gotten a bunch of syringes donated and I've started using them for controlled additions. Less derpy.
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Valentine
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Yesterday I did some experiments on concentrating hydrogen peroxide with a rotatory evaporator. My first try gave me a 53,6 %
H2O2 solution. Next time I measured almost everything. I started with 98 g 30,1 % H2O2 solution and I
could concentate it on 75 °C and 50 mbar to 33 g 67,0 % solution. It means only ~25 % of the H2O2 had decomposed during the
procedure. These concentrations are based on double-checked permanganometric titrations. I used the cleanest flask I had for my first attemption, and
for the second I used one with some spots of selenium or some orange dye. It's interesting that the 53,6 % solution constantly bubbling (not
vigorously, just very slowly) and the 67 % H2O2 in the "dirtier" flask was "in quiet" during the day, I haven't seen a bubble
yet. Probably there was some very little amount of metal salt in the first flask.
[Edited on 31-1-2013 by Valentine]
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APO
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Is hydrogen peroxide miscible with salt water?
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elementcollector1
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Yes.
Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
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Highfields
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I think it is the case that the worst dangers of hydrogen peroxide lie mostly with what happens in the vapour rather than the liquid. Highly
concentrated peroxide was made (by Laporte) and trucked (fairly casually) around the UK back in the 1960's leading up to its use on the launch vehicle
the British used to get their one and only independent satellite in orbit. Subsequently, the whole project was abandoned and manufacture of peroxide
ceased.
Although I do not recommend this to anyone, I did once (just once!) concentrate a quantity of 30% electronics grade peroxide up to around about 90% by
reduced pressure (nitrogen atmosphere) distillation. All of the glassware had been thoroughly cleaned and pre-conditioned before use.
[Edited on 8-2-2013 by Highfields]
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APO
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Hey I found this which is similiar to salting out, but I'm skeptical if it will work, haven't tried it yet.
http://www.instructables.com/id/Distill-Hydrogen-Peroxide/
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elementcollector1
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I call ALL the shenanigans. Hydrogen peroxide should by no means separate from a solution of any salt in water.
Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
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APO
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Sounds right.
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Sedit
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I have yet to use this method that has been running through my mind for sometime now ( I get 35% rather cheep and its more then I need) but if the
opening of a bottle was stuffed with cotton to keep dust out and it was placed in a desiccating bag with a large amount of MgSO4 I would think that
the concentration should in theory get rather high over time. It should be a simple set and forget means of concentration as long as dust from this
desiccating agent was not allowed to come into contact with the H2O2.
Can anyone test this or provide a valid argument as to why this would not work.
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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APO
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No doubts here! I will do it and post my results!
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elementcollector1
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Hydrogen peroxide does decompose on its own, though slowly. I imagine that this would only affect the concentration a little bit at a time, but it may
be worth mentioning.
Alternatively, what of a stronger dessicant such as NaOH or H2SO4?
Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
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DerAlte
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Sounds like BS. H2O2 has a dielectric constant very similar to H2O,~80, and should be an equally effective solvent for ionic substance. The reason is
the ability to form hydrogen bonds, which it shares with HF, HCN and liquid NH3 as a consequence of forming highly polar molecules. The high dielectic
constant allows the dissociation into ions to occurs with greater ease. Very little data is available as to the measured solubility of ionic
substances in H2O2 probably due to its reactivity. I managed to find the following from a quick web seach via Google:
http://www.springerimages.com/Images/Physics/1-10.1007_s1166...
Phase diagram for the system sodium chloride-hydrogen peroxide-water at 283.15 K. SA, solubility of NaCl in water at 283.15 K; w, mass
fraction
This suggests that the solubility of NaCl in a solution of H2O2 and H20 (Miscible in all proportions) differs very little from than in pure H2O. It is
highly dubious that any layer separation could occur due to differential solubility.
Der Alte
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kt5000
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| Quote: Originally posted by shannon dove |
I don't think I would like to be riding next to a tanker truck full of 98% hydrogen peroxide.
Would that be a yellow and an orange placard?
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I'm more concerned about the UPS guy tossing around the box with the 1-gal 98% H2O2 
[Edited on 6-11-2013 by kt5000]
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