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axehandle
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PbO2
How does one produce PbO2? Using Pb filings and H2O2?
I've googled for half an hour now....
Edit: You see, I have this mad idea of making a substrate-less PbO2 anode using my 20-ton hydraulic press and perhaps some sort of inert binder.
Edit2: Skylighter sells PbO2, but doesn't ship it overseas due to its toxicity. Anyone know of a supplier within the EU that does mail order
cross-border?
[Edited on 2004-4-28 by axehandle]
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BromicAcid
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I would say first you have to make you lead into a soluble salt. Dissolve in HCl, or you can use acetic acid vapors but the process is slow. Then
take your lead salt and add the hydroxide of your choosing, like NaOH to precipitate the lead hydroxide. Take the lead hydroxide and add a
hypochlorite like Ca(OCl)2 or possibly NaOCl and your lead dioxide will precipitate out. That is the prep from my chemistry book. I'm sure you
could probably get away with using H2O2 in that last step in place of your hypochlorite though.
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chemoleo
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Hmm maybe NaOCl wouldnt be the best. It normally contains NaCl (obtained via bubbling Cl2 into NaOH), plus it is normally basic.
Not only may your precipitate contain PbCl2, but especially Pb(OH)2 . Better to use Ca(OCl2) which is free of base. On the other hand, a great excess
of NaOCl would probably do the job.
For dissolving lead to get some lead salt, without using nitric acid etc, you could go via the copper acetate route - copper is deposited, and lead
acetate is formed. you cant use copper sulphate as the corresponding lead salt is insoluble. to make copper acetate, either dissolve CuCO3 in acetic
acid, or make it with Calciumacetate/copper sulphate, filter off the calcium sulphate and you are left with copper acetate.
Neat method, made 1.5 kg worth of lead acetate that way, with minimal effort 
[Edited on 28-4-2004 by chemoleo]
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BromicAcid
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| Quote: |
Hmm maybe NaOCl wouldnt be the best. It normally contains NaCl (obtained via bubbling Cl2 into NaOH), plus it is normally basic.
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The first point I totally agree on, but for the second point I forgot to mention that the Ca(OCl)2 solution is supposed to be added to basified
Pb(OH)2.
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axehandle
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Please spoonfeed me.
I can get CuCO3Cu(OH)2 in any quantities, as well as acetic acid (25%) and HCl (30%).
How would I go from there?
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BrAiNFeVeR
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Wouldn't lead oxidise readily if you try water electrolysis with Pb as the anode material?
I once tried it I think and got a brownisch product ... can this be correct ?
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axehandle
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Don't know.... and I don't know how to tell the difference between PbO and PbO2.
If all else fails, I'll order it from a chem company in Sweden, but they are horribly expensive.
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BromicAcid
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I guess I can spoon feed, but only because you posted this in the reagents and apparatus aquisition area and not general chemistry
| Quote: |
I can get CuCO3Cu(OH)2 in any quantities, as well as acetic acid (25%) and HCl (30%).
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If I were doing this I would dissolve my CuCO3Cu(OH)2 in a slight stoichimetric excess of CH3COOH then I would add my lead filings
while stirring efficently. Making sure there was enough liquid to dissolve my end product Pb(OOCCH3)2 and also visually checking the color to see if
there was a appreciable copper salts, if there was I would have to add more Pb.
From here I would filter out the copper then evaporate some of the solution with heat to maybe half volume or until the salt starts to try to
precipitate if it did try to precipitate at a higher temp I would add a bit more water. And while still hot I would add a stoichiometic excess of
NaOH to thoroughly precipitate most of the Pb(OH)2 and allow to cool.
Next step either let it sit around to age the precipitate and decant or filter it. Taking my still moist Pb(OH)2 I would add it to a guestimated
quantity of water but it is somewhat insoluble so even though I would heat the water I would still not expect massive solution of the solid.
Regardless I would make sure the solution was definitely basic, at least pH 11 then start adding Ca(OCl)2 in small portions keeping an eye out for a
brown precipitate of PbO2. If I saw this it would inspire me to go on and add more Ca(OCl)2 until a precipitate was no longer observed, or until a
stoichiometirc quantity was used up.
Filter precipitate, wash thoroughly and attempt to remove Pb(OH)2 remaining by adding the precipitate to a volume of hot water and filtering hot,
doing so till confident that a majority of the Pb(OH)2 was removed from solution. You could add some carbonate to the water remaining from your first
attempt at removing Pb(OH)2 from the solid and precipitate out the even less soluble carbonate to see if Pb+2 is still floating around somewhere.
Although PbO2 is listed as insoluble in water it still might give a positive test so I'm not totally sure on that one.
Also wait for Chemoleo and see if he posts back on the details of the CuAc2 + Pb reaction, being that he made some 1.5 Kg he might have some good
pointers for going about it.
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axehandle
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un-be-fucking-lievable
You won't believe this, but I sent a request for the price of 1kg of PbO2 to the only company in Sweden that does mail order to individuals.
The response was that I would need a fucking PERMIT to purchase lead salts AS WELL AS powdered lead!!!
I replied something along the line that as long as metal files aren't licenced, the permit requirement is quite academic....
Update: Seems MnO2 can be used as a substitute, but not for the chlorate-->perchlorate step. My pottery supplier has MnO2.....
[Edited on 2004-4-28 by axehandle]
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axehandle
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Sucking up.
Right now I'm sucking up to the guy responsible for sales at the company I spoke of. They only sell H2O2 (80%) if they're sure it's not
going to be used for explosives. I've told him lots of my rocketry hobby. We'll see how it goes.
H2O2 should oxidise Pb to PbO2, right?
Edit: Sorry, it's H2O2 35%. About 15 Euro/liter.
[Edited on 2004-4-28 by axehandle]
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chemoleo
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Well here it goes... the dissolution of lead metal with cheap OTC materials. I copied parts over of what I posted at E&W already:
| Quote: |
A while back I managed to solubilse a kilogram of lead with a neat little method. I didnt want to waste HNO3 for the dissolution, neither NH4NO3
etc. Neither did I have any existing lead salts, or lead oxide.
But I did have about 20 kg of solid lead metal, plus 10 kg of copper sulphate (CuSO4), obtained from a gardeners store.
I got it to work as follows:
1. Calcium carbonate is easily obtained, I neutralised a known amount with acetic acid (conc. vinegar), yielding a solution of calcium acetate.
2. I dissolved an equimolar amount of Copper sulphate CuSO4, and added to it the stoichiometric amount of calcium acetate. What you get is copper
acetate and calcium sulphate
3. THe precipitating calcium sulphate is filtered off, then the filtrate is cooled to precipitate more CaSO4, and filtered off again. One is left with
a fairly clean solution of copper acetate, which has a lovely dark green colour and tends to crystallise at the surface of the the liquid.
4. This is probably the longest step - to the solution of copper acetate, one adds a large excess of solid lead metal! the finer the lead pieces, the
better (faster). Over the course of a week or two, the copper acetate colour (dark green) slowly disappears, and becomes completely colourless. What
happened meanwhile is that solid copper deposited as thin sheaths on the solid lead. I found no stirring is needed during those two weeks, the copper
deposited anyway.
5. The solid copper is scraped off the remaining lead, the lead pieces are taken out, and the solution is filtered once again to remove copper pieces
and any more CaSO4
6. One is left with a clear solution of lead acetate. Made from 100% over the counter materials. Slow evaporation of the water in the solution leads
to LARGE crystals of lead acetate, which are very heavy and slowly become milky/powdery on the surface at air! |
| Quote: |
Follo-up: When the Ca acetate started reacting over the course of a week or two, I noticed that an insoluble yellowish substance accumulated at the
side of the reaction vessel.
Thinking, oh, this must be because the HAc evaporates (which is, as I found out later, because the double salt of the hydroxid/acetate forms, plus
possibly PbO), I added 500 ml of 20% HAc to the 5 litres in the reaction vessel - and promptly, the yellowish stuff disappeared, and it was a clear
green (later clear altogehter) solution again.
From that point onwards, I always made sure I keep the solution acidic, with excess acetic acid! |
Well axehandle, there is nothing stopping you! It's a nice and satisfying experiment. I really really hope you do not claim that you can't
find lead sheets/airgun bullets/fishingweights/lead solder anywhere in Sweden! 
PS H2O2 does not necessarily work, I think Bromic only thought it might work too!
[Edited on 28-4-2004 by chemoleo]
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Polverone
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another method
I've used this with good results on lead dust, but I'm not sure how fast it works with larger pieces of lead: boil the lead with ammonium
nitrate solution. Some ammonia and lead nitrite are produced. The main product is a heavy white powder, easily soluble in acid, that I presumed was
the hydroxide or a basic nitrate or a mixture. This white powder was easily dissolved in acetic acid, then treated with Ca(OCl)2 to form lead dioxide.
Another method that I know works to dissolve even large pieces of lead is to use sulfamic acid (often used as a descaler or ingredient in cleaning
products). Lead sulfamate is extremely soluble, far more than the acetate or nitrate, though the solution undergoes slow hydrolysis, precipitating
lead sulfate.
I seemed to find a few things using sulfamic acid to dissolve lead:
Really concentrated solutions of the acid didn't seem to attack lead.
Heating is very helpful.
It may be difficult to get the lead to react initially, but the addition of some hydrogen peroxide (3% works fine) seems to overcome this, when
combined with heat. Pure lead might react better, but I noticed this difficulty with some airgun pellets, made of an alloy that remained shiny
indefinitely (unlike pure lead).
I was able to dissolve airgun pellets completely in an hour or two, using heated sulfamic acid solution. The sulfamic acid is much easier to
get/handle than HNO3 and doesn't produce NO2 when dissolving the lead.
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axehandle
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Thank you all for your suggestions. I'll take them into consideration.
My sucking up worked, I can now order 35% H2O2! We had an interest in common: rocketry!
Edit1: Airgun pellets are an alloy of tin, lead, and antimony.
Edit2: | Quote: |
This white powder was easily dissolved in acetic acid, then treated with Ca(OCl)2 to form lead dioxide. |
Isn't H2O2 an even stronger oxidizing agent than Ca(OCl)2?
| Quote: |
Well axehandle, there is nothing stopping you! It's a nice and satisfying experiment. I really really hope you do not claim that you can't
find lead sheets/airgun bullets/fishingweights/lead solder anywhere in Sweden!
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Heh. I can get tons.
[Edited on 2004-4-28 by axehandle]
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chemoleo
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I tried it - success :)
I happened to have some lead carbonate-acetate at hand - so rather than just looking at it, I used it!
1. I dissolved exactly 10 grams in an excess of acetic acid, and filtered off to get rid of a slight turbidness.
2. To the clear solution NaOH(aq) was added. Once neutralised, a fine pigment white precipitate (Pb(OH)2) was produced, which, upon adding more NaOH
turned yellow. This was reversible however, I acidified with acetic acid once again, and everything went back into solution. Then I adjusted the pH to
pH 10 with NaOH, and collected the white precipitate.
3. The precipitate was resuspended in H2O dest, and the suspension was halfed.
4. To one half an excess of 30% H2O2 was added. The precipitate turned a pale lemmon yellow, with a few bubbles appearing. Thinking, maybe the
reaction is not complete, I started heating it. Now that was a bad idea. At still low temps, a runaway suddenly occurred, and HUGE amounts of
gas/smoke was produced - which thankfully cleared rapidly, indicating it was mostly steam and oxygen (for fear of lead in the air I departed the scene
for a few minutes, and let fresh air do its job)... the yellow precipitate did not change colour, after the runaway, either.
5. To the second solution I added a large excess of NaOCl (with NaCl). Immediately a rust brown precipitate formed. No gas evolved this time, no
chlorine evolution, thankfully. No accidents this time.
Conclusions?
Well I checked some MSDS's:
PbO2: Appearance: Dark brown powder. Incompatibilities: Aluminum carbide, sulfides, hydrogen peroxide, hydroxylamine, combustible and organic
materials.
Pb3O4: Appearance: odourless red or orange powder
PbO: Appearance: yellow-orange powder. Stable. Reacts violently with hydrogen peroxide, strong oxidizing agents, aluminium, zirconium, halogens,
sulphur trioxide, boron, silicon, sodium, zinc.
Well well the conclusion is obvious lol...
NaOCl did indeed produce PbO2, seemingly clean (no PbCl2 precipitate, I would have noticed the crystal needles). I won't mix it with H2O2, thank
you very much 
Now the other reaction, Pb(OH)2 is not as conclusive. Obviously something happened to it, else the colour change wouldnt have occurred. But it's
definitely not PbO2. I guess most likely it's PbO.. or some modification of Pb3O4. I know it doesnt agree with the MSDS description, but I seem
to remember a commercial batch of Pb3O4, which had this lemmony pale colour, too.
Anyway - axehandle, there you have it. No more sucking up to get some H2O2 pls... you dont need it!
PS it's currently drying, hoping to weigh it later.
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axehandle
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chemoleo,
I'm in your debt.
Remains to be seen how I'm going to repay you, considering that I may not be alive tomorrow. I melted about 3 kg total of KCl in my furnace (for
a casting core), and spilt about 1kg down the furnace. Not wanting to stop my casting, I just let it vaporize. The entire flat is filled with atomized
KCl(s). It shouldn't be too poisonous, but I'm a bit worried about osmotic effects on my lungs....
We'll see. Now I just need some very strong acetic acid.
If I die, it's been nice getting to know you all.
Edit: Btw, I'll still order the H2O2 --- it might come in handy at one point or another.
Edit2: I feel really sick now. Shoudn't need any potassium supplements for a while....
Edit3: *cough* cough* The casting sand worked perfectly, btw. If I'm alive tomorrow, I'll cast the burner vessel.
Edit4: From MSDS: "7. HEALTH HAZARD DATA
Inhalation: Extremely high concentrations of dust are typically self-eliminated due to the nuisance conditions they create. Over exposure may produce
irritation of the mucous membranes, nose, throat, coughing and shortness of breath. In addition certain ice melters may contain small amounts of
silica particles less than 5mm in diameter. These silica particles are capable of causing silicosis if inhaled in high enough concentrations over an
extended period of time. The principal manifestation of silicosis if difficulty in breathing. This condition can progress to dry cough, shortness of
breath on exertion, decreased lung function and pulmonary fibrosis."
I interpret this as "you'll get a very dripping nose for a while then you'll be fine". I have no difficulty breathing. Luckily, I
don't have asthma or any allergies.
[Edited on 2004-4-29 by axehandle]
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axehandle
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If anyone was worried...
I feel fine now. A bit of a sore throat, that's all. I panicked there for a while, sorry.....
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axehandle
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Looky, looky.
I had 5 litres of 30% HCl and decided to make some PbCl2 just because possession of lead salts is illegal here.
In this picture you can barely make out 1284g of pure Pb dissolving in 1500g of HCl(aq). It's really, REALLY evolving H2!
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Polverone
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Yuck!
Isn't that filling the air with the horrible biting smell of HCl? The chloride is too insoluble for many purposes anyhow. I suggest acetic acid +
H2O2 as a good combination for dissolving lead that doesn't later hydrolyze and dump insoluble lead sulfate (as sulfamic acid does).
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axehandle
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| Quote: |
Isn't that filling the air with the horrible biting smell of HCl?
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It sure is! I'm having it by an opened window....
Yes, you're right, there are better ways, but I wanted to break the law with what I had at home.... it's one of those days..
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frogfot
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Polverone is right. Make this outside.. even with open windows HCl may destroy some sencitive electronics (some circuits may have very thin leads and
locally no protection against nearby air..).. and not only electronics..
Oh, and small sprinkles from H2 evolution may carry away some lead salts in the air 
PbO2 production is scary..
Btw, how about taking it from car battery? Although PbSO4 should be removed somehow..
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chemoleo
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There's much more joy in making it yourself!
Read above, easy methods are all there!
Still, axe... you are gonna get lots of PbCl2 which is not well soluble. What are u going to do once the lead is covered with it, and the solution is
saturated?
Well I guess as long as you can prevent the PbCl2 coating, its fine... as you have to process your your PbCl2 with NaOH anyhow. And that should work
regardless... providing you work with weighed stoichiometric amounts, and you stir it throroughly and for a good while ...
PS yes I would seriously watch it with HCl fumes. My dad a few years ago nearly killed me when he found all his tools were rusty
[Edited on 17-5-2004 by chemoleo]
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axehandle
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I keep it in a huge jam jar with the rubber lid weighed down, so there is no spattering and very little fuming --- it doesn't smell.
It's still evolving H2, and the solution hasn't been saturated with PbCl2 (yet).
As for what I'm going to use it for: I'm intending to put the PbCl2 in a jar labelled PbCl2(s) just to mock the government.
It's not for making PbO2, for that I'm going with chemoleo's method instead. This is just for fun.
[Edited on 2004-5-18 by axehandle]
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axehandle
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Interesting..... 3 weeks and the lead is still not dissolved in the HCl, even though there's still lots of hydrogen evolving.
Think I'm going to try boiling sheet lead in NH4NO3(aq) today, just for the fun of it.
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chemoleo
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Make sure (for a change ) you dont inhale the fumes coming off it. They really
ARE nasty!
Plus, be careful not to explode the NH4NO3. That is even NASTIER!
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axehandle
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| Quote: |
Make sure (for a change ) you dont inhale the fumes coming off it. They really ARE nasty!
Plus, be careful not to explode the NH4NO3. That is even NASTIER!
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Ah, yes, thanks for the concern. I wasn't intending to heat a mixture of NH4NO3 and Pb DRY though.... (mixing it with diesel oil or perhaps water will
be much safer...
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