Sciencemadness Discussion Board

synthesis of H2o2??

thereelstory - 3-2-2010 at 18:21

does anyone have any good suggestions for a synthesis of 1 liter batches of hydrogen peroxide?

chemoleo - 3-2-2010 at 18:56

Please search the forum... there must be at least a dozen threads on this...

thereelstory - 3-2-2010 at 20:23

ok still learning the tricks of navigation....utfse

thereelstory - 3-2-2010 at 20:34

the problem is these h202 posts have lead to dead ends, or at best diluted h202. how increadible would it be for one of these geniuses on here to come out with an illustrated breakdown for conc h202.

Sedit - 3-2-2010 at 22:08

That would be great.... I tell ya what, you solve the decomposition problems and we will work on the synthesis when you got that worked out.


Why not just find ways to dehydrate aq H2O2 or risk your life distilling which is gonna enter the synthesis somewhere.

hissingnoise - 4-2-2010 at 04:34

IIRC, concentrated H2O2 is dangerous to handle but you can buy 35% H2O2 quite easily.

User - 4-2-2010 at 05:39

Concentrated hydrogenperoxide can easily light a piece of paper, saw a nice demonstration once.

You could look into electrolyses preparation books ive seen h2o2 mentioned there a couple of times.
but really dont bother and search for a good supplier.

DJF90 - 4-2-2010 at 05:51

Wikipedia mentions the method I've seen before...

ScienceSquirrel - 4-2-2010 at 07:10

Food grade 35% hydrogen peroxide is as cheap as chips, about £15 a litre where I live.
As a laboratory reagent it is about as strong as you would want to go under normal circumstances

hissingnoise - 4-2-2010 at 07:43

And 'food grade' means no stabilisers so it should be stored in a fridge.


thereelstory - 4-2-2010 at 09:18

whats wrong with PURE hydrogen peroxide?

hissingnoise - 4-2-2010 at 09:39

It decomposes over time; CH3OH, and other substances, is added as a stabiliser.
Unadulterated, it's slightly thermally unstable!
With higher concentrations than 35% stability falls off quite quickly!



[Edited on 4-2-2010 by hissingnoise]

DJF90 - 4-2-2010 at 10:16

Quote: Originally posted by hissingnoise  
With higher concentrations than 35% stability falls off quite quickly!


Not true... In fact quite the opposite. 90% Hydrogen peroxide (so long as it is very pure) requires no stabiliser and the rate of decomposition is approx. 1% per year at 30*C, which is much less than for 30-35% solutions

[Edited on 4-2-2010 by DJF90]

Magpie - 4-2-2010 at 12:57

Quote: Originally posted by thereelstory  

.. how increadible would it be for one of these geniuses on here to come out with an illustrated breakdown for conc h202.


Or: why don't "one of these geniuses" just stop whatever project they happen to be working on and develop a recipe with photos so I can be spoonfed.

ScienceSquirrel - 4-2-2010 at 13:20

Quote: Originally posted by thereelstory  
whats wrong with PURE hydrogen peroxide?



Really concentrated hydrogen peroxide eg 70+% is a lot more dangerous than 35% hydrogen peroxide.
Some materials will catch fire on contact with it and it will decompose explosively to steam and oxygen on contact with catalysts such as finely divided metals.
The 35% hydrogen peroxide is a good compromise as it is concentrated enough to be shipped economically but at the same time it can be handled fairly safely and it is widely used as a sterilising agent in the food industry and elsewhere.
However contact with the skin of the hands causes white burns that rapidly become very painful, you do not want to get it elsewhere!

hissingnoise - 4-2-2010 at 15:41

Quote:
Not true... In fact quite the opposite. 90% Hydrogen peroxide (so long as it is very pure) requires no stabiliser and the rate of decomposition is approx. 1% per year at 30*C, which is much less than for 30-35% solutions

That's surprising DJF90, I assumed H2O2 resembled HNO3 in that regard.
I still wouldn't like to have to handle 90% H2O2 because presumably some minor contamination could cause an explosive decomposition.

thereelstory - 4-2-2010 at 17:01

im a rookie wanna be science freak. spoon fed is a good place to start. i figure there are plenty of intelligent people here who have contributed for the sake of sharing information. for those who modus operandi is quid pro quo, give me a few years and i will gladly reciprocate, after i learn to walk....this is definitely the best science forum i have ever come across.

watson.fawkes - 4-2-2010 at 17:15

Quote: Originally posted by thereelstory  
im a rookie wanna be science freak. spoon fed is a good place to start. i figure there are plenty of intelligent people here who have contributed for the sake of sharing information.
If you'd like to be spoon fed, then don't expect to pick your project. There are a number of detailed tutorials out there. Pick one and go.

ScienceSquirrel - 4-2-2010 at 17:34

90+% hydrogen peroxide is highly sensitive and a monopropellant.
Dropping your girlfriend's silver neck chain in to a beaker holding half a litre of 90% hydrogen peroxide could result in an explosion that will kill both of you instantly and probably destroy the building you are standing in.

bquirky - 4-2-2010 at 20:03

Hi gents I found this review paper and thought it may be usefull on this thread



Attachment: h2o2-review.pdf (774kB)
This file has been downloaded 6006 times

DJF90 - 5-2-2010 at 02:40

I never said it would be nice to work with, just that its more stable than 30-35% so long as its sufficiently pure.

hissingnoise - 5-2-2010 at 04:42

90% would be interesting though - powering these things. . .
http://www.tecaeromex.com/ingles/peroxidoi.html

ScienceSquirrel - 5-2-2010 at 06:20

Quote: Originally posted by thereelstory  
im a rookie wanna be science freak. spoon fed is a good place to start. i figure there are plenty of intelligent people here who have contributed for the sake of sharing information. for those who modus operandi is quid pro quo, give me a few years and i will gladly reciprocate, after i learn to walk....this is definitely the best science forum i have ever come across.


If you think anyone on here is going to spoon feed you instructions on making high test hydrogen peroxide you are very foolish indeed.
Have a look at the peroxide rocket site, very pure hydrogen peroxide is safe if you have the skills and experience to handle it but a mistake is very serious indeed.
You do not want to 'learn to walk' making it, you might as well learn to drive on the autobahn.

chief - 5-2-2010 at 06:21

What about this way: (?)

BaO2 + H2SO4 → H2O2 + BaSO4

Should give high concentration, BaO2 could be made from ordinary BaO ... ;
... then the BaSO4 could be recycled ...
==> So the only necessary input-chemical would be H2SO4 ...

ScienceSquirrel - 5-2-2010 at 06:29

Quote: Originally posted by chief  
What about this way: (?)

BaO2 + H2SO4 → H2O2 + BaSO4

Should give high concentration, BaO2 could be made from ordinary BaO ... ;
... then the BaSO4 could be recycled ...
==> So the only necessary input-chemical would be H2SO4 ...


That is a classical way of making hydrogen peroxide but the reaction is carried out with dilute sulphuric acid to produce a weak aqueous solution that is then distilled.
Concentrated acid would produce Piranha solution and you really do not want to go there!
http://en.wikipedia.org/wiki/Piranha_solution


[Edited on 5-2-2010 by ScienceSquirrel]

ciscosdad - 25-5-2010 at 20:26

My 2c worth

Thanks to Kewls, terrorists and acetone peroxide, H2O2 is becoming increasingly hard to get. At least here in Oz.
Last time I looked they were not even stocking the 3% stuff in my local pharmacy. In due course, things will go the same way in all sorts of places.
A practical method of producing 30% Hydrogen Peroxide may well be a useful addition to the already comprehensive collection of preparations we have. The high concentration stuff is mostly unnecessary for the preparations referred to in these pages.

I'm afraid I'm an armchair chemist these days (aside from minor dabblings) , so I would be a mere spectator, but I recommend one of you guys with the expertise and resources think along these lines.

Of course I would love to be proved wrong but I'm not holding my breath..... :-(
If anyone from Oz has any suggestion for a current source easily available, please P2P. Not on open forum.

doofos - 16-9-2013 at 03:33

First route is like this: if H2O2 decomposes over a catalyst into O2 and H2O steam and heat, then reverse the process. Feed O2 and water steam over a thin catalyst mesh and add heat. When H2O and O2 react into H2O2 then this reaction absorbs heat and the output is hot H2O steam, colder H2O2 and hot O2. H2O2 needs to be separated, water and oxygen can be reused and fed again to the catalyst.

Second route:
*Heat washing soda Na2CO3 under vacuum, it decomposes to sodium oxide Na2O and CO2. (use high temperatures)

*Heat Na2O under pressure of pure oxygen. It absorbs O2 and transforms to Na2O2.

*Gently react Na2O2 with cold water to obtain H2O2 and titrate in acid to neutralize NaOH because H2O2 is stabile in acidic.

*Or some other route from Na2O2 to H2O2.