Hydrogen Peroxide Decomposition

[DominF]

Hey there, I'm investigating the decomposition of hydrogen peroxide and, after attempting to write the plan up, realised I have quite a lot of questions. ^^;

 

1. How are gases that spontaneously decompose stored? (stupid question I know)

2. I'm expected to investigate the use of inhibitors and buffer solutions, but beyond simply using them then not using them, how would I get a large range of data? Is it possible in this case to use varying amounts?

3. I'm meant to be using yeast as a catalyst, I know it's not used up in the process but I'm still not sure how much of the solution I should be using in comparison with the amount of hydrogen peroxide. Any suggestions?

 

Thanks!

[Darkblade48]

I'm not quite sure of why you are investigating 1). The decomposition product (oxygen) of hydrogen peroxide is not a gas that would spontaneously decompose.

 

2) I'm not sure what kind of analysis technique is available to you, but in general, all hydrogen peroxide sold today contains an inhibitor and/or buffer.

[Fable]

if i understood correctly - you want to use yeast to break h2o2 into h2o and o2. rather obvious i think - that the peroxide would just kill the yeast? yet again, what are you trying to do?

[thedarkshade]

If you're thinking of decomposing H2O2 into H20 + O2 , then you don't really need to do anything, because H2O2 is not stable itself! All it need is sun rays and it will break into H2O + O2, I think!!!

[Ozone]

Hmm, my guess is that DominF intends to use yeast as a source of catalase. Catalase *catalyzes* the break-down H2O2 in-vivo to prevent excessive oxidative stress; this is why (besides Fe) that H2O2 effervesces on contact with blood. It does the same for yeast.

 

Try looking *here*:

 

http://www.science-projects.com/catalasekinetics.htm

 

You can also try out metals to decompose your H2O2. These might include Fe2+ (or Fe3+ with a reducing agent), W or MnO2. Comparing and contrasting these kinetics with those acquired with catalase would found a much stronger project.

 

Please, at least try an internet search! It was a trifle to find the link I posted for you here.

 

Merry Christmas (yes, I said it),

 

O3

[zfy5956]

use enzyme "hydrogen peroxide enzyme--Catalase"

[ChemSiddiqui]

use enzyme "hydrogen peroxide enzyme--Catalase"

 

Good idea. You can [extract] get it from leaves of green plants!

[chemogirl]

hi

im just a year 8 but we did this in class today and H2O2 decomposes on its own, but a catalyst that is very very quick and efficient is MnO2

[hermanntrude]

iodide, catalase and MnO2 all work very well. Also I think platinum works

[UC]

hi

im just a year 8 but we did this in class today and H2O2 decomposes on its own, but a catalyst that is very very quick and efficient is MnO2

 

I've done this with 15% H2O2 and (I think) activated charcoal. The water was boiling by the time it ran out of H2O2 because the decomposition is quite exothermic. Before it got so hot that the steam interfered, I was doing the "glowing wooden splint" demonstration. It flares up quite impressively in a mostly oxygen atmosphere.

 

The inhibitors and buffers in [math] H_2O_2 [/math] are almost always just phosphoric acid and acid phosphate salts to regulate the pH. [math] H_2O_2 [/math] is much less stable in alkaline solution.

 

MnO2 is also a fantastic catalyst. Iodide ion is also good. Google "elephant toothpaste" for demonstrations that use soap to trap all the gas being produced.

 

Liver is an excellent source of catalase. I did that experiment in 7th grade biology with blended raw liver and 3% hydrogen peroxide. There are also enzymes that catalyze the oxidation of compounds by [math] H_2O_2 [/math]. For example, blend peeled turnip and water and strain through cheesecloth. The liquid has a fair amount of peroxidase in it. Upon adding dilute hydrogen peroxide solution, buffer, and guiacol solution, the color goes from clear to yellow and then to browns as guiacol is oxidized to tetraguiacol. Without the peroxidase, the process only occurs very slowly.

[Semicon]

I am also looking into decomposing H2O2. The reason I need to do it is that I use this in manufacturing process. I currently have to pay to have it disposed of. It is expensive. I can’t just leave it around and wait until it decomposes on its own. I need an inexpensive way to decompose it that does not produce a hazardous material.

 

I was looking into using Na2CO3.

 

Does anyone know what that makes when it is reacted with H2O2 or of another safe alternative method?

[insane_alien]

you could just pass it over a copper catalyst. you'll get steam and oxygen off of it, both can just be discharged to the atmosphere.

[Patrick Henry]

If you're thinking of decomposing H2O2 into H20 + O2 , then you don't really need to do anything, because H2O2 is not stable itself! All it need is sun rays and it will break into H2O + O2, I think!!!

 

Isn't this why as time progresses, the peroxide's reactivity will decrease?

[hermanntrude]

also any iodide salt would work as a catalyst

[coke]

I've tried sodium iodide, it works, but it's a far second to MnO2.

 

Just saw open a small battery (preferably new, AA is great) it will contain zinc, MnO2, and some slippery KOH will spew out (I suggest you wear gloves)... There will be slippery silver zinc in the center covered with little plastic layers and some black stuff outside of it. This is MnO2. Maybe a little Mn2O3. Good enough, violent bubbling in H2O2. (1 liter 3% H2O2 solution (~50 moles) has 1.5 moles H2O2, or .75 moles O2 (30 milliliters gas))

 

I don't think it's dangerous, although the first time I did it, I worried that the battery would blow up or something. Yet, the reaction is fairly weak, I took about 10 AA batteries worth of zinc and MnO2, and mixed them in a can, they heated up a little bit, but no sparks or flashes or anything.

 

If you have some liquid nitrogen lying around, please don't get the idea to

, it's dangerous! Edited April 5, 2009 by coke

[Semicon]

Thank you all for the information. It is very helpful. I am sure that I am being a pain, but with the manufacturing we end up with some very specific requirements. I can't have copper in the water I send down the drain, so a copper catalyst would be risky for my purposes. The reason I was investigating Sodium Carbonate was that it was inexpensive and presumably didn't make anything hazardous. I mixed them in my lab and is was effective at decomposing the H2O2. I used 35% H202 and washing soda from the grocery store (only $3.99). My main concern at this pont is that the resulting mixture was green. I am not 100% certain that I know what my reaction has produced. I am definitely not an expert, that's why I am looking for information here.

[hermanntrude]

your products shouldnt be green at all, i think. you might (but shouldnt really) expect some green to appear with copper, but not sodium carbonate. Sodium compounds are usually colourless

[John Cuthber]

Just saw open a small battery (preferably new, AA is great) it will contain zinc, MnO2, and some slippery KOH will spew out (I suggest you wear gloves)...

QUOTE]

Gloves are probably a good idea but I'd say safety glasses/ goggles are more important.

 

Anyway, while it's true that you can use all sorts of things to decompose H2O2, I suspect that yeast will be one of the easiest to write a risk assessment for.

Platinum's expensive; liver (unless it's food grade) is probably listed as a biohazard; the water treatment people don't like much copper in waste streams, and manganese is neurotoxic.

 

Lord knows what the green colour was- presumably an impurity from somewhere.