| Pages:
1
2
3
4 |
froot
Hazard to Others
Posts: 347
Registered: 23-10-2003
Location: South Africa
Member Is Offline
Mood: refluxed
|
|
The Germans used hydrazine hydrate and hydrogen peroxide in manned rocket planes, this was their answer to cheaper aerial combat. They would shoot
these poor buggers off in these 'planes' to go shoot down allied planes. The rocket engine only lasted a few minutes so he had to make the
most of his trip and then try and safely glide the thing back to the field.
The project was cancelled when one crashed and the tank holding the hydrazine burst and half dissolved the poor pilot. Incredible!
We salute the improvement of the human genome by honoring those who remove themselves from it.
Of necessity, this honor is generally bestowed posthumously. - www.darwinawards.com |
|
|
Saerynide
National Hazard
Posts: 954
Registered: 17-11-2003
Location: The Void
Member Is Offline
Mood: Ionic
|
|
Edit: Off topic, but....
Wouldnt he have died from the crash first? 
[Edited on 20-1-2004 by Saerynide]
|
|
|
Hermes_Trismegistus
National Hazard
Posts: 602
Registered: 27-11-2003
Location: Greece, Ancient
Member Is Offline
Mood: conformation:ga
|
|
Uses for h2o2 go WAY back.
I seem to remember that the Japanese used a couple mini-subs using h202 as fuel component in the subs that attacked pearl harbor and that the British
had used a similarly designed sub (during WW1?) that used peroxide. I saw a layout about it in National Geographic.
| Quote: | Originally posted by Saerynide
Edit: Off topic, but....
Wouldnt he have died from the crash first?
[Edited on 20-1-2004 by Saerynide] |
I wonder how they explained that to the relatives?...(sending the body home in a jug)
Arguing on the internet is like running in the special olympics; even if you win: you\'re still retarded.
|
|
|
Saerynide
National Hazard
Posts: 954
Registered: 17-11-2003
Location: The Void
Member Is Offline
Mood: Ionic
|
|
Ewwwww.... =S
|
|
|
Theoretic
National Hazard
Posts: 776
Registered: 17-6-2003
Location: London, the Land of Sun, Summer and Snow
Member Is Offline
Mood: eating the souls of dust mites
|
|
Another way to concentrate H2O2 is to add an anhydrous salt that forms hydrates readily. For example, calcium chloride. 110 grams will absorb 108
grams of water (on formation of hexahydrate), and I bet it will settle out as (easily filtrable) crystals.
|
|
|
simsalabin
Harmless
Posts: 3
Registered: 25-10-2003
Member Is Offline
Mood: No Mood
|
|
what about freezing ?
it freezes at -35 celisus.
boiling h2o2 will cause degradation
|
|
|
chloric1
International Hazard
Posts: 1142
Registered: 8-10-2003
Location: GroupVII of the periodic table
Member Is Offline
Mood: Stoichiometrically Balanced
|
|
Break out the Dry ice and Acetone freezing mixture!And keep the peroxide out of the acetone!
[Edited on 1/31/2004 by chloric1]
Fellow molecular manipulator
|
|
|
Hermes_Trismegistus
National Hazard
Posts: 602
Registered: 27-11-2003
Location: Greece, Ancient
Member Is Offline
Mood: conformation:ga
|
|
.....mmmmmuuuugggghhhh!..... aspirator (homer)
| Quote: | Originally posted by simsalabin
boiling h2o2 will cause degradation |
Boil at reduced pressure.
Arguing on the internet is like running in the special olympics; even if you win: you\'re still retarded.
|
|
|
Ramiel
Vicious like a ferret
Posts: 484
Registered: 19-8-2002
Location: Room at the Back, Australia
Member Is Offline
Mood: Semi-demented
|
|
Theoretic: kewls remember to use regular, and not glass filtering paper when filtering dehydrated solutions of 90%
H<sub>2</sub>O<sub>2</sub>
But seriously - won't high conc. peroxide attack glass fibre even?
Caveat Orator
|
|
|
vulture
Forum Gatekeeper
Posts: 3330
Registered: 25-5-2002
Location: France
Member Is Offline
Mood: No Mood
|
|
Glass fibre is a no no as filter material. It's a tiny bit basic, so...
If you're going to distill H2O2, you're going to need to clean your glassware with concentrated HNO3. After that with H2SO5 and finally
rinse it with diluted H2O2. Then add some phosphoric acid as stabilizer.
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
|
|
|
jimwig
Hazard to Others
Posts: 215
Registered: 17-5-2003
Location: the sunny south
Member Is Offline
Mood: No Mood
|
|
Hey there ----mr a-bab, what about putting up that "90% H2O2" regime........
|
|
|
BromicAcid
International Hazard
Posts: 3246
Registered: 13-7-2003
Location: Wisconsin
Member Is Offline
Mood: Rock n' Roll
|
|
The other day at the library I was looking though some book and actually ran across a reference that said solutions of hydrogen peroxide in ether are
more stable then those in water... odd...
Anyway, I just found out some interesting information about the peroxide that I normally use. I buy it from a hair care place and it says on the
bottle 40 volume Hydrogen Peroxide, I always assumed that either meant it was near 40% or perhaps it was done same as alcohol and 40 volume was like a
proof and it was actually 20% so today I did some checking and found the actual concentration.
10 volume = 3% H2O2
20 volume = 6% H2O2
And etceteras, so, my H2O2 is only around 12%, very disappointing, I guess I might have to concentrate by freezing. Oh well, it's getting cold
out. I really have no need for anything above 30% and solutions stronger then that kind of give me the creeps considering I've seen this 12%
stuff I normally work with behave very strongly toward what I would consider mild conditions.
Aside from that, it was mentioned that one might use anhydrous salts to sap the water from a hydrogen peroxide solution, wouldn't many salts
simply uptake the peroxide in place of water to form the hydrate, I know some salts do, but do they all?
Edit: One other thing, I've heard that barium peroxide can be precipiated from cold water, this seems to be supported by it forming a stable
octohydrate and that hydrate having a temperature at which it looses its water of hydration, but does anyone have any experience with this?
[Edited on 11/25/2004 by BromicAcid]
|
|
|
S.C. Wack
bibliomaster
Posts: 2419
Registered: 7-5-2004
Location: Cornworld, Central USA
Member Is Offline
Mood: Enhanced
|
|
I went to the library last Sunday to look up the ozone via H2SO4 electrolysis refs. Not that I have Pt electrodes, just curious. The only peroxide sp.
gr. tables that I had were in 10% increments, so I wrote down what was in one of the refs that I stumbled on while doing so. I think that this was at
16C: 20% = 1.0725, 25% = 1.0918, 30% = 1.1122, 35% = 1.1327, 40% = 1.1536, 45% = 1.1749.
I've made small amounts of the Ba and Na peroxide hydrates from the hydroxides and H2O2. Not sure how well these dry out, at least without P2O5
in the vacuum dessicator. But they do precipitate very nicely out of the H2O2 and are easily isolated quickly. I seem to remember reading somewhere
that heating without vacuum gives loss of O as well as water, so I haven't tried that.
One of the books that I scanned and uploaded to axehandle, Oxidations in Organic Chemistry, mentions the preparation of anhydrous H2O2 in Et2O from
the 30% peroxide if anyone ever needs such a thing.
I make all of my peroxide now, in not small amounts, from drugstore 3%. I hoard it when it is on sale, 3 pints for $1. I used to just let it evaporate
because with the stabilizers and all, if you use big clean (buffed to a polish) glass mixing bowls then dust is not a problem. Even 35% can have a
bunch of dust on it and not bubble at all. Yields were high. Metal is another story. But then I found that heating below 70C will concentrate to 45%
with little loss of O2.
I've tried the freezing yet I use heating. But that's me.
Don't know if this has been mentioned before, but the volume thing is based on how much O can be released from 1 ml of the peroxide; e.g. 1 ml of
3% H2O2 can release 10 ml of O.
Off topic, but the only other thing that happened at the library Sunday, other than the peroxide refs (and being required to present photo ID in
addition to my library card!) was accidentally stumbling onto an interesting Na production lecture demonstration from JCE. Looks like Cyrus was onto
something when he mentioned using light bulbs in the unconventional Na thread, sort of, but he got no love. I uploaded it to axehandle as
na_from_nano3_and _a_light_bulb.pdf. Someone might want to see exactly how much Na a light bulb could produce if left on long enough. I paid too much
for mine to not use it, so it's up to someone else.
[Edited on 25-11-2004 by S.C. Wack]
|
|
|
Axt
National Hazard
Posts: 795
Registered: 28-1-2003
Member Is Offline
Mood: No Mood
|
|
Ive shaken H2O2 with ether, I think you would have a hard time hurting yourself with the mix, unless there is crystals floarting around in it. Though
apart from burning myself with the extract I havnt pursued it further. Oh, I was using 50% H2O2 in ether as well, so more "dangerous".
Another thought, Is pure silica gel inert towards H2O2? Another attempt I made to concentrate the 50% was by pouring it over silica gel containing
blue/pink indicator The prills exploded as it catalysed the breakdown of the H2O2.
By soaking the prills in H2SO4, to try and kill the indicator, washing them with water and drying for 1.5hr at 150° there was no more blue colour.
These prills only slowly attacked the H2O2. So im thinking the indicator is the problem, but it could also be explained by residual H2SO4 stabalising
the mix (which it DOES do with the gel).
So someone may want to try adding H2O2 to pure silica gel (pull it out of a shoebox or something), sodium silicate works to concentrate H2O2, but its
soluble. Imagine pouring H2O2 into the top of a tube filled with silica gel and concentrated H2O2 exiting out the bottom, this seems to good to work
|
|
|
rocketscience
Harmless
Posts: 13
Registered: 21-11-2004
Member Is Offline
Mood: No Mood
|
|
If you need 100% h2o2 I would recommend making the 90% pure and adding ether potassium superoxide or sodium peroxide to it they would chemical react
with the remaining water to make h2o2 the I would let it evaporate in a still however ko2 and na2o2 are expensive and in order to make yourself you
have to take pure na or k and burn it with pure oxygen
|
|
|
Polverone
Now celebrating 21 years of madness
Posts: 3186
Registered: 19-5-2002
Location: The Sunny Pacific Northwest
Member Is Offline
Mood: Waiting for spring
|
|
The indicating silica gel uses cobalt chloride to do its indication, and of course cobalt compounds effectively catalyze H2O2 decomposition. Adding
alkali metal peroxides or superoxides to H2O2 to bring it to 100% sounds like a recipe for disaster. H2O2 decomposes more rapidly in alkaline
conditions, and of course it wouldn't be pure even if it didn't explode because it would have sodium or potassium compounds left in it.
PGP Key and corresponding e-mail address
|
|
|
budullewraagh
Hazard to Others
Posts: 168
Registered: 1-8-2004
Location: new york
Member Is Offline
Mood: Aliphatic
|
|
i heard before something about bubbling NO2 into conc H2O2 to form HNO3...can that happen? or do you need a platinum catalyst?
|
|
|
Esplosivo
Hazard to Others
Posts: 491
Registered: 7-2-2004
Location: Mediterranean
Member Is Offline
Mood: Quantized
|
|
NO2 dissolves in water giving a mixture of nitric (III) and nitric (V) acids, i.e. HNO2 and HNO3 respectively. H2O2 oxidizes the HNO2 to HNO3 - no
need of any catalyst IIRC. As a side note, but wouldn't that be a 'waste' of H2O2. HNO2 is oxidised to HNO3 by bubbling air through the
solution.
Theory guides, experiment decides.
|
|
|
budullewraagh
Hazard to Others
Posts: 168
Registered: 1-8-2004
Location: new york
Member Is Offline
Mood: Aliphatic
|
|
i see. bubbling air?
|
|
|
FrankRizzo
Hazard to Others
Posts: 204
Registered: 9-2-2004
Member Is Offline
Mood: No Mood
|
|
Dry air, specifically.
|
|
|
budullewraagh
Hazard to Others
Posts: 168
Registered: 1-8-2004
Location: new york
Member Is Offline
Mood: Aliphatic
|
|
eh...so sorta using pressure or something?
|
|
|
BromicAcid
International Hazard
Posts: 3246
Registered: 13-7-2003
Location: Wisconsin
Member Is Offline
Mood: Rock n' Roll
|
|
It's just the oxygen in the air oxidizing the nitrous acid thus formed and any nitrogen monoxide to allow more of the nitrogen dioxide entering
the solution to be absorbed as nitric acid.
|
|
|
FrankRizzo
Hazard to Others
Posts: 204
Registered: 9-2-2004
Member Is Offline
Mood: No Mood
|
|
You'd want to bubble air from a common air pump (fish aquarium pump would work fine) through a drying tube containing calcium sulfate or a
similar desiccant, into your NO2 contaminated acid. Make sure that the tubing that you're using is acid resistant as well (PTFE).
|
|
|
BromicAcid
International Hazard
Posts: 3246
Registered: 13-7-2003
Location: Wisconsin
Member Is Offline
Mood: Rock n' Roll
|
|
Stirring a solution of H2O2 during freezing seems to be a good thing in that it will allow for better heat conduction in the solution and result in
smaller pieces of ice which could be filtered from the solution and reduce the risk of a solid sheet forming across the top and breaking a beaker.
However by that same process the freezing point will be depressed somewhat due to the motion and if the stirring is too high could an even higher
percentage of the peroxide end up in the ice? How about adding a piece of ice once it gets sufficiently low in temperature to function as a seed
crystal?
I haven't found answers to these little questions in my little excursion into peroxide concentration and I was hoping someone could help.
Found another hydrogen peroxide FAQ
|
|
|
Eclectic
National Hazard
Posts: 899
Registered: 14-11-2004
Member Is Offline
Mood: Obsessive
|
|
A rotovap does a fine job of concentrating 30% H2O2 to better than 70%. There is a much bigger diference in the boiling points than there is in the
freezing points.
|
|
|
| Pages:
1
2
3
4 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
