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axehandle
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PbO
"Lead monoxide, or litharge (PbO), a yellow, crystalline powder formed by heating lead in air, <snip>".
No temperature given, no other conditions given. Should it be powdered prior to heating? Would melting it and roast the mass at 1000 degrees C do the
trick? Would I have to perform a specific series of dance steps? 
This is what I've found. After googling for 30 minutes, only finding references to a mythical substance called <i>litharge</i>, which
I've deduced is an archaic name for lead monoxide. Nothing about how it's manufactured.
I need a largeish quantity of lead monoxide as a reagent. It's very illegal here for environmental concerns, so I can't
<i>buy</i> it...
So.... Has anyone solved this little problem already and would care to illuminate me..?
Edit: I have a very sophisticated electrochemical process to carry out, and the only thing lacking is the fscking PbO ........
[Edited on 2004-6-19 by axehandle]
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Reverend Necroticus Rex
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I have had SOME success in producing small quantities by heating very thin flakes of lead in air with a blowtorch, but it's very innefficient as
you have to heat a pretty small amout bit by bit in thin flakes so it burns rather than melts.
On the other hand, I have got a yellow mass from heating the brown lead peroxide found in car batteries that I THINK is litharge, not 100% sure
though.
[Edited on 19-6-2004 by Reverend Necroticus Rex]
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axehandle
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No, no, no!
That would take the entire weekend and probably just end me up with lead poisoning....
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BromicAcid
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Decomposing lead nitrate should yeild lead monoxide.
This PDF has a short interesting section on litharge.
Sounds like heating lead in air is just a surface reaction and atomization of the molten lead is necessary for good yields.
| Quote: | On exposure of lead to moist air at ordinary temperatures
the suboxide (Pb2O) is formed ; when melted in contact with
air it is converted to monoxide (PbO), the yellow amorphous
massicot being first formed at a low red heat, while, at a
higher temperature, a bright red heat, this undergoes a
molecular change with conversion to crystalline litharge.
Steady heating at a temperature of from 300 to 500° C. con-
verts litharge (PbO) into red lead (Pb8O4), but this is dis-
sociated at 550° C. |
From http://www.dli.gov.in/data0/000/229/TXT/00000027.txt
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axehandle
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Having no access to lead nitrate, this would be difficult.
The PDF is interesting, but "... Today the molten lead is atomized by whirling propellers and allowed to oxidize through contact with the
air..." is a bit beyond my abilities, at least without building... <b>Hmm.</b> Interesting project, but...
What I'd really prefer would be a way to convert the hydroxide to the monoxide, chemically. I may be hunting a ghost here though (does not
exist).
Edit1: I have an idea.... lead filings in a pure oxygen atmosphere should burn quite vigorously, I think..... hmm.
Edit2: Another one would be bubbling air through molten lead..... I just hope it wouldn't spatter too much... A copper pipe could be bent in an
"L" shape, the end of the shorter side crimped and small holes drill along it... this part would then be submerged in molten lead and air be
pumped into the upper end of the pipe... probably lots of pressure would be needed though if the holes were clogged...
[Edited on 2004-6-19 by axehandle]
[Edited on 2004-6-19 by axehandle]
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Step 1: Convert the lead into lead acetate using Chemoleo's method.
(Prepare a saturated solution of copper acetate, and add an excess of lead to it. The lead will displace the copper ions, forming lead acetate. The
metallic copper produced on the surface of the lead will periodically flake off, and so even with thick pieces of lead, the reaction will go to
completion.)
Step 2: Add sodium carbonate solution. Filter out the precipitated lead carbonate.
Step 3: Thermally decompose the lead carbonate, to yield PbO. Do this in an oxygen-free atmosphere to prevent oxidation into Pb3O4.
1f `/0u (4|\\| |234d 7|-|15, `/0u |234||`/ |\\|33d 70 937 0u7 /\\/\\0|23.
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axehandle
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| Quote: |
Step 1: Convert the lead into lead acetate using Chemoleo's method.
(Prepare a saturated solution of copper acetate, and add an excess of lead to it. The lead will displace the copper ions, forming lead acetate. The
metallic copper produced on the surface of the lead will periodically flake off, and so even with thick pieces of lead, the reaction will go to
completion.)
Step 2: Add sodium carbonate solution. Filter out the precipitated lead carbonate.
Step 3: Thermally decompose the lead carbonate, to yield PbO. Do this in an oxygen-free atmosphere to prevent oxidation into Pb3O4.
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This sounds workable. Thanks.
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BromicAcid
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| Quote: | | I have an idea.... lead filings in a pure oxygen atmosphere should burn quite vigorously, I think..... hmm. |
Burning in a pure oxygen atmosphere usually brings out the higher oxidation state of an element. Therefore I would think you would get a high
percentage of PbO2 as well.
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Esplosivo
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Lead (II) oxide turns to trilead tetraoxide at around 450 deg celcius. Lead (II) carbonate decomposes at 400 deg celcius (at its melting point). Is
the inert atmosphere really required - its a drawback since it complicates apparatus etc... . Off topic but what is the max temperature that can be
reached by a common bunsen burner? Thanks.
Theory guides, experiment decides.
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axehandle
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Depends on the fuel. With propane, the maximum temperature in about 1300 degrees C.
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chemoleo
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PbO from Pb(OH)2 + H2O2
I don't know if you remember, but in the PbO2 thread I subjected Pb(OH)2 to both NaOCl and H2O2.
With the former I clearly got PbO2.
With the latter, I got a bright yellow precipitate, and which is likely to be PbO (what else could it possibly be?).
Maybe try some kind of titratration to find out whehter this is true. If so, it is probably more economical to simply get PbO from Pb(OH)2 with H2O2
rather than decomposition of PbCO3 at high temperatures.
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al93535
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Easy Lead oxide
I have made lead oxide before a few times with great results. Although it was a by product of what I was making. Heat KNO3 and lead shavings until the
KNO3 melts. Keep it molten for about an hour. Works great. I used a old pot and a blowtorch. Of course to make it easier you could fill a steel pipe
with it and throw it onto a fire. After it cools, chip out the yellow solid and dissolve it in water. The lead monoxide will not dissolve and thus can
be filtered out. I was making Potassium Nitrite which is what dissolves.
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Esplosivo
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I proceeded and used chemoleo's method for the production of PbO. I first added NaOH to a solution of lead acetate until I noticed the ppt
starting to 'dissolve' (it was forming soluble sodium plumbate (II)). Then I added an excess of H2O2. It seemed that any amount I was mixing
just kept on fizzing. Well at a certain point I stopped adding H2O2. A yellowish-brown ppt was formed. I tried filtering this using a normal
coffee-filter, but the ppt came right through the filter! How can this be prevented?
I did a sort of qualitative test. I added 69% nitric acid and the ppt dissolved indicating that the ppt is not PbO2 (which as far as I remeber does
not react with nitric acid), and therefore indicating the presence of PbO - although the colour of the ppt was enough as an indication.
Edit 1: I was thinking. What if I first add a largish volume of water to the mixture, then leave the ppt settle at the bottom, decant the top layer
and then evaporate off the water by heating? The addition and decanting of the water might be done several times to improve purity. All I must do is
take care the PbO is not completely dry so that it would not form higher oxides.
[Edited on 24-6-2004 by Esplosivo]
[Edited on 24-6-2004 by Esplosivo]
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chemoleo
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Well, when I tried it, I used analytical reagents (all of them), and an excess of 30% H2O2.
THe yellow colour change from the clean white Pb(OH)2 occurred immediately, as far as I remember.
On the note of it fizzing - be warned that in the PbO MSDS it states incompatibility with H2O2. I found out why - once I heated it. The mixture heats
up to boiling in seconds, and vast quantities of gas are evolved. Any tight necked container might shatter, I was lucky to use a 500 ml beaker. But
it's no problem if it isn't heated.
I didnt use filtration, I used centrifugation. Letting it settle is an alternative of course. The yellow PbO has been on air since, and no noticeable
colour change occurred - so maybe the formation of higher oxides isn't an issue at RT.
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Esplosivo
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| Quote: |
THe yellow colour change from the clean white Pb(OH)2 occurred immediately, as far as I remember.
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Maybe I didn't express myself well. The colour changed occured immediately on addition of H2O2. Its only that effervesnce continues at any amount
of H2O2 added. I think that the PbO formed is acting as a catalyst to decompose H2O2.
On a side note, I used a 250ml beaker - wide enough for small quantities. Anyone knows if this oxidation can be carried out using the carbonate
instead of the hydroxide?
Curiosity won and I must ask  For what are you going to use this PbO axe?
(perchlorate cell?!)
[Edited on 24-6-2004 by Esplosivo]
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Chemtastic
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I don't suppose there's a thermite-esque reaction, where the element and oxide of one yields the element and oxide of another?
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Esplosivo
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| Quote: | Originally posted by axehandle
Edit: I have a very sophisticated electrochemical process to carry out, and the only thing lacking is the fscking PbO ........ |
You see there is an electrochemical process involved
[Edited on 24-6-2004 by Esplosivo]
Theory guides, experiment decides.
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axehandle
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| Quote: |
[Curiosity won and I must ask For what are you going to use this PbO axe? (perchlorate cell?!)
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I not going to use it for anything, now that I've found a cheaper source of copper carbonate. But if I had found an easy + cheap method of making
PbO (I was trying to find a method using only what I had at home at the time) I would have dissolved it in acetic acid to form lead acetate. Lead
acetate is one of the usable lead salts in the ceramic substrate PbO2 anode construction process that's outlined in the patent I mentioned in the
PbO2 thread...
Now, that's not all the reasons I want(ed) PbO... the other is just the fact that possession of it is illegal here! I like to do (harmless)
things that are (stupidly) illegal. It makes me feel good.
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kazaa81
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PbCl making with no success
Hallo to all,
This is procedure for making PbO(2???),
finded in this forum...
----------------------------------------------------
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.
---------------------------------------------------
Well, for me seem ok, but, I've tried to
dissolve Pb in HCl, with no success, why?
Later, I've tried with Pb finely divided, but with no success again.....
I am involving a possible procedure (dissolving Pb in HCl) or no?
Any information about simple Pb salts is welcomed!
Thanx for help.
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JohnWW
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Re: PbO dissolution in HCl
I posted a few days ago on this subject on another topic. I noted that the electrochemical potential for Pb to go into solution as Pb++ at the expense
of H2 is only -0.13v, and other some sources put Pb below H in the electrochemical series. Also, the PbCl2 that forms is only very slightly soluble,
except in boiling water. This means that the dissolution of Pb or PbO in HCl is initially very slow, and is soon arrested due to the PbCl2 layer.
John W.
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chemoleo
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Oh comon, Kazaa, all the questions you have are covered! See the PbO2 thread for details.
And yes, with hypochlorite, you get PbO2.
As to the dissolution of lead salts - again, its been covered in depth!
Either it's
Pb + HCl + H2O2 (slow)
Pb + HAc + O2 (air bubbled through for weeks --> slow)
Pb + HNO3
Pb + Cu (Ac)2
All of these work, to a lesser or greater extent. The choice is yours.
Just read up, and then you won't need to write questions that have been covered many times before !
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BromicAcid
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A chunk of lead boiled in HCl for about an hour will yield some crystals in the beaker when it cools back down, dissolving Pb in HCl is a pain in the
butt, I just use my good nitric although that is a waste, I suggest Chemoleo's method any day.
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halogen
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litharge... hmm, interesting.
If im not mistaken, can't it be mined?
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Theoretic
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Yes, but we want to make it chemically. 
Maybe PbAc2 can be straight roasted on air to give PbO? Reduction of Pb++ with the decomposition products of CH3COO- (CO, H2, CH4, C are the main
ones) can be prevented by stirring the powder (careful: don't agitate too hard to create dust) on air while heating so oxidation is the main mode
of decomposition.
Or heat at low temperature to make PbO and acetic anhydride.
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Esplosivo
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The temp. must be controlled since PbO forms Pb3O4 when heated to above >200deg celcius if I remeber correctly. Anyway, I find the rxn of Pb
ethanoate and H2O2 to give a very good (and pure) source of PbO. The main problem is the seperation of the product - centrifugation is the way to go I
suppose.
Theory guides, experiment decides.
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