DrMario
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Best H2O2 stabilizer, in your experience?
(Since this topic is closely related to H2O2 storage, I thought it could fit in this subforum. Sorry if I was wrong!)
If you are making plans for medium-to-long term storage of concentrated H2O2 (where "concentrated" may mean 30% or more), the question of using a
stabilizing chemical must have crossed your mind. Of course, refrigeration is always nice, but if you can't afford it, you will look at..
- HCl? When I was learning about chemistry in junior high, I read about using H2SO4 for this purpose, but nowadays HCl seems to be more prevalent
- Sodium triphosphate
- Sodium pyrophosphate
- Sodium citrate
- some other, new and shiny chelating agent?
For whatever reason, sodium citrate didn't work for me. The problem may very well have been "between the chair and the keyboard". Sodium triphosphate,
OTOH, seems to be very nice for stabilizing 35% H2O2 over very long periods of time.
What I found extremely important was cleaning the bottles in which H2O2 is to be stored, with 1M HCl. This seems to nicely remove the metallic ions,
which are most responsible for H2O2 decomposition.
So this is my experience - what's yours?
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Texium
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I don't have much experience with this, but I'm not sure if storing a solution of concentrated H<sub>2</sub>O<sub>2</sub> with
HCl is such a good idea since this will liberate some chlorine gas and then leave you with a mixture of
H<sub>2</sub>O<sub>2</sub>, Cl<sub>2</sub>, and H<sub>2</sub>O.
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plante1999
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Phosphoric acid worked for me.
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DrMario
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That makes sense - phosphoric acid will create insoluble salts with most metals. Quantitatively speaking, how does it compare with the chelating
sodium phosphates, do you know?
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DrMario
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Quote: Originally posted by zts16  | | I don't have much experience with this, but I'm not sure if storing a solution of concentrated H<sub>2</sub>O<sub>2</sub> with
HCl is such a good idea since this will liberate some chlorine gas and then leave you with a mixture of
H<sub>2</sub>O<sub>2</sub>, Cl<sub>2</sub>, and H<sub>2</sub>O. |
I don't know myself, I tried it briefly because I read that it is used to stabilize H2O2. It did work for me, but that particular batch wasn't in
storage long enough for me to gauge its effectiveness in the long term. I'll say this, though: I tried adding as little as possible, but I still ended
up with more than I was comfortable with. In contrast, I needed to add very tiny amounts of sodium triphosphate - in the order of a few hundred
micromolar concentration.
EDIT: As for leaving me with a mixture of H2O2, Cl2 and H2O... well, my H2O2 was never as highly concentrated as to make a bit of added H2O a problem.
Also the Cl2, even if produced, would have been minute, due to the small amount of HCl, a few millimolar concentration.
[Edited on 4-11-2014 by DrMario]
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Texium
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Yes, the point was primarily that the HCl would no longer be present and wouldn't be doing you much good after it decomposes.
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DrMario
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| Quote: Originally posted by zts16 | | Yes, the point was primarily that the HCl would no longer be present and wouldn't be doing you much good after it decomposes. |
Ah, now I see. Okay, fair point indeed.
I have a tiny amount of HCl-stabilized H2O2. Can't discern any Cl2 by sniffing it, but at these low concentrations it may all be in solution, perhaps.
The other thing I notice is no evolution of O2, either. This is a 25% H2O2 sample.
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Dr.Bob
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Here are some great sites to check, tin salts are commonly used in the past, I have not heard of using HCl but have heard of phosphates.
http://h2o2.evonik.com/product/h2o2/en/about/faq/pages/defau...
http://www.h2o2.com/faqs/FaqDetail.aspx?fId=11
http://h2o2uses.com/hydrogen-peroxide-grades-and-stabilizers
from above:
"Manufacturers of drug store grade hydrogen peroxide do not, as a rule, identify the stabilizers used in their product; however, it is well known that
the most common stabilizer of H202 is acetanilide. Other agents known to be used as stabilizers include phenol, tin, Colloidal stannate,
organophosphonates, and nitrate."
and
"Most commercial grades of H2O2 contain chelants and sequestrants which minimize its decomposition under normal storage and handling conditions.
The types of stabilizers used in H2O2 vary between producers and product grades. Common stabilizers include:
Colloidal stannate and sodium pyrophosphate (present at 25 - 250 mg/L) are traditional mainstays.
Organophosphonates (e.g., Monsanto's Dequest products) are increasingly common.
Nitrate (for pH adjustment and corrosion inhibition) and phosphoric acid (for pH adjustment) also are used.
Colloidal silicate is used to sequester metals and thereby minimize H2O2 decomposition in certain applications that depend on the bleaching
ability of H2O2 in alkali.
In some applications, a high degree of stabilization is needed; whereas, in others (e.g., drinking water treatment or semiconductor manufacture)
product purity is more important. For most environmental applications, H2O2 stabilization does not affect product performance."
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DrMario
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Thanks Dr.Bob. I did know about sodium stannate as a good H2O2 stabilizer. The problem was that I had difficulty sourcing any, so I ended up...
completely forgetting about it.
I've not heard ofacetanilide. I'll definitely look into it.
What about your personal experience, Dr.Bob?
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Dr.Bob
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I buy H2O2 and use it how it comes, so I don't worry much about it. I have used bottles that were older than I am, and they normally worked well.
Most of the peroxide I have used was for lab demos, cleaning stuff, and non-critical uses.
But I don't use peroxide that often, much more of a reducing kinda guy. For that I like NaCNBH3, NaBH4, LAH, and Borane. And of course H2.
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