View Full Version : Obtaining Pure Oxygen
how could I go about getting pure oxygen from hydrogen peroxide?
and once i do... is oxygen gas flammable or does it simply accelerate the spreading of the fire? like could i just take a blow torch and blow up a balloon filled with pure oxygen or not?
Vir Novus
2008-12-11, 21:39
Can't you just get an oxygen tank from a blowtorch at the hardware store?
Oxygen encourages the spreading of fire, but it doesn't burn itself. I mean, our atmosphere is like 20% oxygen. I've messed with a blowtorch with just the oxygen turned on. It's pretty need. Like if you heat iron red hot and then blow oxygen on it, it lights up like a sparkler. And if you have a block of wood that's smoldering a little, and blow oxygen on it, it'll go up in flames.
If you fill a balloon with a mixture of acetylene and oxygen, and then light that, you'll get a nice explosion. Make sure you use some sort of fuse though, unless you want to go deaf.
InspiredByMe
2008-12-11, 22:21
Manganese dioxide and hydrogen peroxide react to form pure oxygen. you can get manganese dioxide from battery cells.
That's a very dangerous reaction, Iv seen rockets powered by it.
Abyssal Kink
2008-12-12, 00:38
It's much easier to go from water to pure hydrogen and oxygen via electrolysis. I saw an interesting setup in an old chem text book. I'll have to go dig it up to give you exact directions...
when i was hydrogenating something i used H generated from HCl + Al
Abyssal Kink
2008-12-12, 00:43
With this setup, it was dependent on where the anode and electrode were positioned. It separated each gas into different containment units.
InspiredByMe
2008-12-12, 00:52
That's a very dangerous reaction, Iv seen rockets powered by it.
Its not that dangerous i obtained a lot of it using one test tube that had a rubber stopper with some plastic tubing attached to it, if you do it in small amounts, with only 3% or 6% h2o2 it should be fine
asilentbob
2008-12-12, 01:00
Yeah, dilute H2O2 isn't very reactive...
If your going to make substantial amounts, I'd recommend more concentrated H2O2... If it needs to be dry you should run the produced O2 through some CaCl2 or something... as the heat liberated from the reaction will make a mist of H2O...
BUT... you can buy small practically disposable O2 cylinders, along with propane, butane, and MAP gas from most hardware stores... for cheap... so why you would want to go the expensive route... is stumping me...
Mokothar
2008-12-12, 22:47
MgO2 is a good catalyst as mentioned before.
Much less known is that some salts of alkali and halogens also act as catalysts, such as KI and KBr.
iceshrike
2008-12-14, 05:27
Really? I would think that would liberate the halogens from the salts.
Sentinel
2008-12-14, 07:22
Hmm, lots of misinformation flying around here.
That's a very dangerous reaction, Iv seen rockets powered by it.
Rockets are indeed powered by H2O2, however, the decomposition in rockets is catalyzed by a platinum mesh. Also, the hydrogen peroxide is at least 50% concentrated, if not higher (upwards of 90% has been used). The drugstore H2O2 you buy is 3%. The reaction with MnO2 is completely safe.
It's much easier to go from water to pure hydrogen and oxygen via electrolysis. I saw an interesting setup in an old chem text book. I'll have to go dig it up to give you exact directions...
meh, it's easy to DO, but hard to capture the gas, and also hard to get enough power flowing to get usable amounts of gas from it. Also, you need to use an electrolyte like NaOH because if you use NaCl you will evolve Cl2 gas and other nastiness at where the oxygen is created.
Best option is still the hardware store bottles in the plumbing section if you need a lot of it.
Mokothar
2008-12-14, 10:54
Really? I would think that would liberate the halogens from the salts.
Quite possibly yes, I- can be oxidised into I2 for example, but you need an acidic environment for this (IIRC)
wolfy_9005
2008-12-14, 16:39
It's only like $10 for a 1L cannister....
And it's a powerful oxidizer :)
Sentinel
2008-12-15, 07:12
...although, stunningly, oxygen is NOT the best oxidizer!
wolfy_9005
2008-12-15, 14:22
...although, stunningly, oxygen is NOT the best oxidizer!
Yeh i never could figure out why....
Mokothar
2008-12-15, 16:30
Oxidising potential, try expressing it in electrons per volume, Oxygen gas scores horrible under normal atmospheric pressure.
Just imagine, one mole of KClO4 releases 8 moles of electrons. that's less than 140g of powder, which is what, half a cup depending on crystal size?
You'd need 2 moles of oxygen gas to do the same, which would come close to 45 liters of gaseous oxygen.
Then there's the practicality of working with gasses, and the fact that oxygen isn't a very strong oxidiser (reactivity wise)
8 litres - £12.95
http://www.firebox.com/firebox/search?searchstring=oxygen&Submit.x=0&Submit.y=0&Submit=Go
Although I'm guessing you're not within firebox's delivery range.
EDIT: Actually they deliver everywhere.
Red Nelpse
2008-12-29, 08:02
how could I go about getting pure oxygen from hydrogen peroxide?
High school biology; Drop in a bit of fresh liver and the enzymes in it start to break up the hydrogen peroxide to water and oxygen.
High school biology; Drop in a bit of fresh liver and the enzymes in it start to break up the hydrogen peroxide to water and oxygen.
That's more chemistry actually.
Mokothar
2008-12-29, 15:25
That's more chemistry actually.
overlap/gray area
Sentinel
2008-12-31, 07:13
Yeah, I did that experiment in high school biology. The second part of it was using MnO2...
MH-iforgotmypassword
2009-01-03, 08:01
Disposable 02 cylinders are actually sort of expensive compared to refillable 02 cylinders, so if you're going to use more than a few liters, "splurge" on a real tank.
Cutting steel with an oxy tank is actually done by heating the metal with a fuel+oxy flame, and then turning down the gas but not the oxygen so that the metal burns... it's pretty fun /infuriating depending how good you are at it.
And a pure 02 balloon will not explode, in case no-one said that. I was skimming.