Tacho
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Practical catalyst for H2O2 decomposition.
Manganese dioxide, MnO2, is the most popular catalyst to decompose H2O2 into H2O + O (actually 2H2O2->2H2O +O2). But is also a black pigment and a
fine powder (a.k.a. “cement black”) that stains everything and its a pain in the ass to recover from the reaction.
Mix MnO2 with sodium silicate (waterglass) until it’s thick. Add some acid. I added glacial acetic acid, but most acids should work. The mix quickly
crystallize. Stir the mass with a glass rod and wash it in a sieve so that any fine powder left is washed away.
What you have now is MnO2 embedded in medium sized crystal of silica gel that are much easier and cleaner to use and recover.
H2O2 decomposes nicely when exposed to it. Silica gel is resistant to most solvents and harsh reaction conditions.
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Mongo Blongo
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There are many other catylists you could use like KMnO4,FeSO4. There is a thread around here somwhere disgussing the oxidation of ethanol to
acetaldehyde with H2O2 which mentions some more catylists.
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Tacho
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How interesting! So you suggest using potassium permanganate instead of a fully recoverable sand-like catalyst made from spent batteries?
Please, I would like to hear more!
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Organikum
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blood.
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axehandle
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Yes, this works. We tried it in college, and it made a bubbling mass several liters large out of only 0.1 liters of blood. Can be ordered at any
butcher (pig's blood is cheapest) for next to scratch.
My PGP key, Fingerprint 5D96 E09E 365D 1867 2DF5 C2FE 4269 9C19 E079 CD35
\"Verbing nouns weirds the language!\"
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Chemtastic
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Use a bit of ground up liver. It has this enzyme...oh what's it called...that breaks down hydrogen peroxide into water and oxygen...it'd be
available at any grocery store...who'd raise eyebrows at people buying liver?
EDIT:
Catalase! That's the name of the enzyme, i think.
[Edited on 20-6-2004 by Chemtastic]
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Tacho
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Now, let me list what we got:
1) Potassium permanganate – cheap, widely available and very easy to clean. As fully recoverable as FeSO4! .................................Irony? What irony?
2) Menstruation - useful only once a month.
2) Pig’s blood – I’m speechless!
3) Chopped liver – Would you recommend bovine or chicken’s would be fine?
4) A fully recoverable sand-like catalyst made from spent batteries, waterglass and vinegar?
Difficult choice!
Well, that's why we are here: discuss new options!
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BromicAcid
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HBr!! Hydrobromic acid decomposes H2O2 nicely but the evolution of some Br2 can be a nusince/blessing in some cases. Worked with that today to asses
the purity of the HBr(aq) I made last week.
Edit: Tap water also decomposes my 40% H2O2 
Edit 2: Wait, HBr(aq) really isn't practical at all...
Edit 3: I guess Tacho's method sounds great after consideration. But how often do you need to decompose H2O2? I did it once or twice to refill
oxygen cylinders but that was all. If I need oxygen for a reaction careful decomposition of perchlorates or chlorates always suits me, anhydrous
oxygen at it's best. Personally my H2O2 is better suited for oxidation reactions under acidic conditions.
[Edited on 6/20/2004 by BromicAcid]
[Edited on 6/21/2004 by BromicAcid]
[Edited on 6/21/2004 by BromicAcid]
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The_Davster
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Tacho: I do not think that the source of liver matters as all meat livers will contain catalyse as it is necessary to decompose the H2O2 formed during
cell respiration.
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bennator
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One chemistry textbook I looked at used Iodine catalyzed decomposition of Hydrogen Peroxide as an example for a bunch of kinetics problems, but
I've never actually done the reaction, so I don't know at what concentrations, etc.
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Cyrus
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How about silver?
Just plunk a silver coin ($5 for a whole one) or any silver foil/pellets (what I use)etc. in H2O2.
Much easier than waterglass/MnO2/acid.
Flinn Scientific says that manufacturing waterglass is beyond a chem. teacher's abilities. How hard is it?
-quote from
http://66.102.7.104/search?q=cache:ZeRF1VQYHCoJ:193.97.251.50/intl/images/henkel_group/hr34e01.pdf+manufacture+of+waterglass&hl=en&ie=UTF-8
"Finally, in the hydrothermal production ofwaterglass, digestion and dissolution take placein a single step. This process was brought
toindustrial maturity by Henkel at the end of theseventies. By-passing the high-temperature proc-ess, alkali metal silicates are directly obtained
asliquid waterglasses from sand and sodium hydrox-ide at temperatures around 200 °C and underhigh autoclave pressures of about 20 bar. "
It seems to be pretty hard.
What does NaOH + SiO2 yield at less pressures? Wouldn't this work!?
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Tacho
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Rogue chemist,
Thank you. That post (bovine or chicken) was a joke. My original post describes an easy way to support a catalyst. I think other fine powder catalyst
can be supported that way to become more filterable. That’s the point of the thread.
I’m sure there are many possible catalysts for H2O2 decomposition. Everywhere I spill some H2O2 it fizzes! MnO2 is mentioned in most textbooks,
it’s a classic!
I find the given suggestions, except silver, unpractical or outright funny! But that is a personal opinion and, as I said, I am here to discuss ideas
and learn.
Cyrus,
Waterglass, a.k.a. sodium silicate, is a very common chemical. It has many uses in different fields and I’m pretty sure a search in the net will
give you a supplier. It is used in waterproofing concrete and fireproofing paper (pyrotechnics) for example.
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vulture
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Doesn't Cu2+ decompose H2O2? Or is my memory failing badly here...
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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t_Pyro
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Are you talking about Cu<sup>+</sup> being oxidised to Cu<sup>2+</sup> by H<sub>2</sub>O<sub>2</sub>?
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Polverone
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sodium silicate's easy
Strong hot sodium hydroxide solution plus sand will yield sodium silicate. Do the reaction in a steel or expendable glass container. Or, faster, do it
with molten sodium hydroxide and sand.
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unionised
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Yeast and platinum both work.
If you have access to both of these then you can make more of one by leaving it in warm sugar solution with a few nutrients.
If you can get the other one to reproduce itself under these conditions please pm me.
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vulture
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| Quote: |
Are you talking about Cu+ being oxidised to Cu2+ by H2O2?
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No, I am talking about catalytic decomposition.
Here it is:
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Sehr reines W. ist bei 20 °C beständig, doch nimmt die Zers.-Neigung mit steigender Temp. zu, insbes. bei Anwesenheit von Spuren katalyt. wirkender
organ. Substanzen od. Cu-, Fe- od. a. Schwermetall-Salze.
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So Cu, Fe and heavy metal salts in general will catalyze the decomposition.
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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Cyrus
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Great! Now I've GOT to make some sodium silicate- it fascinates me for some odd reason. Maybe it's the name, waterglass- a
contradiction... Or it could be the fact that Flinn Scientific told me that I
couldn't possibly make it. 
Flinn says regarding waterglass, "It is prepared using a high-temperature, high-pressure process and cannot be made in lab."
I would suppose that the high pressure drives the reaction more towards the products, eh? Or is it a complete reaction even in a NaOH soln. with
glass. Why on earth would industry use the high pressures then? Maybe it speeds up the reaction.
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sanity gone
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I don't know if you were looking for anything stylish, but the cheapest decomositoin method is probally bleach
H<sub>2</sub>O<sub>2</sub> + NaOCL --> H<sub>2</sub>O + O<sub>2</sub> + NaOCl
[Edited on 6/21/2004 by sanity gone]
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vulture
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That equation is wrong IMHO.
The reaction should produce Cl2. Which makes it unsuitable for O2 production.
EDIT: Hang on, I could be wrong here. Anyways, it doesn't look feasible to me that the NaOCl remains after the reaction.
[Edited on 21-6-2004 by vulture]
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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Polverone
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maybe this instead?
NaOCl + H2O2 -> H2O + NaCl + O2
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Chemtastic
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I still like the enzyme catalase from beef (yes, it says bovine!) liver...
I wish I had a scanner...the pic in this chem book looks like it's a pretty rapid decomposition
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sanity gone
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Polverone is right. I made a stupid mistake (I was trying to remember the reaction from a lecture) The Proper reaction is:
NaOCl + H<sub>2</sub>O<sub>2</sub>--> NaCl + H<sub>2</sub>O +O<sub>2</sub>
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