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Earl Snake-Hips Tucker
01-24-2008, 11:55 AM
Most commercially available H2O2 is available as a “solution” (something like 5%, IIRC).

Anyway:

Why isn’t “pure” H2O2 sold? My WAG is cost and practicality, that most consumer applications work fine with just a solution, and that by putting it in a solution, it goes a lot longer (for the manufacturer).

I’ve always assumed that drinking H2O2 would not be good for me. Would I get sick, either with the solution or the pure stuff?

steronz
01-24-2008, 12:08 PM
I actually learned quite a bit reading through the wiki... I just figured it was pretty caustic in higher concentrations, but I had no idea straight hydrogen peroxide was a rocket propellent.

Hydrogen peroxide works best as a propellant in extremely high concentrations-- roughly over 70%. Although any concentration of peroxide will generate some hot gas (oxygen plus some steam), at concentrations above approximately 67%, the heat of decomposing hydrogen peroxide becomes large enough to completely vaporize all the liquid at standard temperature. This represents a safety and utilization turning point, since decomposition of any concentration above this amount is capable of transforming the liquid entirely to heated gas (the higher the concentration, the hotter the resulting gas). This very hot steam/oxygen mixture can then be used to generate maximal thrust, power, or work, but it also makes explosive decomposition of the material far more hazardous.

http://en.wikipedia.org/wiki/Hydrogen_peroxide

Tapioca Dextrin
01-24-2008, 12:13 PM
I’ve always assumed that drinking H2O2 would not be good for me. Would I get sick, either with the solution or the pure stuff?

From the MSDS (http://bu.edu/es/labsafety/ESMSDSs/MSHydPeroxide.html#anchor888417)

Danger! Strong oxidizer. Contact with other material may cause a fire. Harmful if inhaled. Corrosive. Causes eye and skin burns. May cause severe respiratory tract irritation with possible burns. May cause severe digestive tract irritation with possible burns.
Target Organs: None known.

Potential Health Effects
Eye:
Causes eye burns. Produces irritation, characterized by a burning sensation, redness, tearing, inflammation, and possible corneal injury.
Skin:
Causes skin burns.
Ingestion:
May cause severe and permanent damage to the digestive tract. Causes gastrointestinal tract burns. May cause perforation of the digestive
tract. May cause severe digestive tract irritation with abdominal pain, nausea, vomiting and diarrhea.
Inhalation:
Harmful if inhaled. May cause irritation of the respiratory tract with burning pain in the nose and throat, coughing, wheezing,
shortness of breath and pulmonary edema. Causes chemical burns to the respiratory tract. May cause ulceration of nasal tissue, insomnia, nervous tremors with numb extremities, chemical pneumonia, unconsciousness, and death.
Chronic:
Prolonged or repeated skin contact may cause dermatitis.

robby
01-24-2008, 12:18 PM
Hydrogen peroxide is a very strong oxidizing agent, and is not very stable. It spontaneously decomposes into water and oxygen, releasing heat in the process. At very high concentrations (>70%), the heat released during decomposition can actually vaporize the remaining liquid. Because it spontaneously decomposes, concentrated hydrogen peroxide has to be stored in special vented containers.

As the concentration increases, it gets progressively more dangerous. High concentrations of hydrogen peroxide spilled on clothing or other combustible materials can cause the material to spontaneously combust. High concentrations spilled on skin causes severe chemical burns.

If you drank pure hydrogen peroxide, it would kill you, and it wouldn't be pleasant.

KneadToKnow
01-24-2008, 12:23 PM
If you drank pure hydrogen peroxide, it would kill you, and it wouldn't be pleasant.
From this and the above posts, I'm imagining a death somewhat along the lines of the one sufferred by the hapless "lucky shot" gunnery officer on Captain Kruge's bird of prey. Owie.

Polycarp
01-24-2008, 12:26 PM
I actually learned quite a bit reading through the wiki... I just figured it was pretty caustic in higher concentrations, but I had no idea straight hydrogen peroxide was a rocket propellent.



http://en.wikipedia.org/wiki/Hydrogen_peroxide

First Astronaut: My God! Why is there a corpse of a naked blonde in orbit?

Second Astronaut, looking closer: She's not a natural blonde.

:D

Solfy
01-24-2008, 12:52 PM
I've worked with 30% hydrogen peroxide. It has to be kept refrigerated at all times. It comes in a special vapor venting bottle. It's not pure liquid evil, but close to it. I got some residue from the outside of the bottle on my hand when putting it back in the fridge. The skin on the surface of my hand died off where it touched.

With many things in life, concentration matters. There are a lot of chemicals that are beneficial in small amounts that will kill you in large amounts.

beowulff
01-24-2008, 01:48 PM
Concentrated H2O2 was used to power torpedoes...

Solfy
01-24-2008, 02:23 PM
What percentage is used to bleach hair? Not the 3% we use as antiseptic is it?

Hairdressers' hydrogen peroxide is sold in "volume" levels of 10, 20, and 30 (and possibly 40). The 10 volume approximately corresponds to the 3% you mention, with the 40 volume working out to about 15%. There's a good explanation on the H2O2 wiki (http://en.wikipedia.org/wiki/Hydrogen_peroxide).

Cluricaun
01-24-2008, 02:53 PM
If all this is true (and I know it is) then what in the hell is this food grade hydrogen peroxide stuff? (http://dfwx.com/goewebsite.htm)

Solfy
01-24-2008, 03:13 PM
If all this is true (and I know it is) then what in the hell is this food grade hydrogen peroxide stuff? (http://dfwx.com/goewebsite.htm)

Frankly I'm sort of surprised they make this available to consumers, but then one can aquire all sorts of lovely things off the internet these days, no?
One can get up to 50% from Aldrich (http://sigmaaldrich.com/catalog/search/ProductDetail/SIAL/516813), but I don't believe they'll ship that off to just anyone.

The disclaimer on that site amuses:
UPDATE: Can 35% food grade hydrogen peroxide be used for making chemical bombs?
With recent publicity of a terror plot involving using "peroxide", questions have arisen whether 35% concentration hydrogen peroxide could be used to make explosives? The answer is no. 35% hydrogen peroxide is by volume 35% h2o2 and 65% h2o (water). Unless a person could figure how to make an explosive device from water, there is no manner to use 35% concentration hydrogen peroxide to make any explosive device or compound.

I see no mention of handling precautions, oh, wait, it's on another page:
WHY IS HYDROGEN PEROXIDE NOT SOLD IN HEALTH SUPPLEMENT STORES ?


While some now do, most do not. The primary reason is to avoid lawsuits founded in foolishness of some people and because of limited shelf life. 35% Food Grade hydrogen peroxide should be stored in a cool, completely dark location - which does not lend itself to retail over-the-counter sales.

Right. . .

Barrington
01-24-2008, 03:28 PM
Concentrated H2O2 was used to power torpedoes...Also submarines (the WWII German Walther turbine), but never made it into production mainly because of the storage and handling difficulties and dangers.

Post-war, the US Navy experimented the same way based on the Walther design, but abandoned the project for similar reasons. As someone at the time concluded "hydrogen peroxide and submarines just don't mix".

The reason that both countries were experimenting with this means of propulsion was that it would give subs (which at the time were all diesel-electric) hugely extended submerged times as well as very high underwater speed.

Bobotheoptimist
01-24-2008, 03:56 PM
The second coolest classroom demonstration in "Chemistry of Hazardous Materials" was pouring hydrogen peroxide on assorted substances and watching them ignite. For a while after, I eyed the bubbling peroxide on various scratches and scrapes with suspicion.

yabob
01-24-2008, 05:22 PM
The second coolest classroom demonstration in "Chemistry of Hazardous Materials" was pouring hydrogen peroxide on assorted substances and watching them ignite. For a while after, I eyed the bubbling peroxide on various scratches and scrapes with suspicion.
Not to mention using it loosen ear wax. OTOH, the bottle of 3% medicinal hydrogen peroxide tells you to gargle with the stuff. That's where I draw the line.

Max Torque
01-24-2008, 05:34 PM
Not to mention using it loosen ear wax. OTOH, the bottle of 3% medicinal hydrogen peroxide tells you to gargle with the stuff. That's where I draw the line.
Done that. Actually, in my experience, the bottle tells you to dilute the amount you're going to gargle with an equal amount of water, which leaves you with a 1.5% solution if my elementary math skills are correct.

Anyway, it didn't taste bad at all; didn't taste like anything, really. Foamed like a mofo, though, and required a couple of spits to relieve the pressure to continue swishing. Sure does make your mouth feel squeaky clean afterwards.

Squink
01-24-2008, 05:35 PM
That's where I draw the line.Before or after gargling?
If after, Catalase (http://en.wikipedia.org/wiki/Catalase) will protect you, and provide your mouth with a burst of oxygeny goodness.

Malacandra
01-24-2008, 06:02 PM
Hydrogen peroxide is a very strong oxidizing agent, and is not very stable. It spontaneously decomposes into water and oxygen, releasing heat in the process. At very high concentrations (>70%), the heat released during decomposition can actually vaporize the remaining liquid. Because it spontaneously decomposes, concentrated hydrogen peroxide has to be stored in special vented containers.

As the concentration increases, it gets progressively more dangerous. High concentrations of hydrogen peroxide spilled on clothing or other combustible materials can cause the material to spontaneously combust. High concentrations spilled on skin causes severe chemical burns.

If you drank pure hydrogen peroxide, it would kill you, and it wouldn't be pleasant.

To add to the joys of hydrogen peroxide, you have to realize that when it decomposes into water and oxygen, you're getting individual oxygen atoms. Oxygen doesn't like going around like that. It wants to be happily settled down as part of a molecule. It will form molecules by itself (as about 19% of the atmosphere attests) but, while it's temporarily in atomic form, it isn't too fussy about what it can get. Think of it as a 2am barfly with serious beer goggles - any hookup at all counts as a score.

You may have seen that thing you do with magnesium ribbon where you light it and let it burn brightly in air, and then put it in a jar full of pure oxygen where it blazes much, much brighter. That's the different between 19% oxygen and 100% oxygen. Well, atomic oxygen ramps it up a step further. Be moderately afraid.

Broomstick
01-24-2008, 06:25 PM
Concentrated H2O2 was used to power torpedoes...

And rocket planes (http://en.wikipedia.org/wiki/Me_163_Komet). Rocket planes that had a disturbing tendency to spontaneously explode on take-off, landing, or for no explicable reason while sitting on a flight line.

Bewildebeest
01-24-2008, 07:11 PM
And torpedo propellant. The explode at the wrong time kind (http://en.wikipedia.org/wiki/Russian_submarine_Kursk_explosion) .

The Scrivener
01-24-2008, 08:59 PM
For more on HTP-fueled torpedoes and the 2000 sinking of the Russian nuclear submarine Kursk, there's this thread (http://boards.academicpursuits.us/sdmb/showthread.php?t=315813&highlight=Kursk+peroxide).

That French conspiracy-theory film cited in the Wiki article sounds like complete BS, BTW.

rbroome
01-24-2008, 10:37 PM
Concentrated H2O2 was used to power torpedoes...
except that it is so dangerous as to be a great hazard to the sub. The Kursk was sunk by leaking H2O2 from their torpedoes.

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