Sciencemadness Discussion Board

Path to Lead tetroxide

Tabun - 27-9-2015 at 05:53

This is probabily the most stupid and "too much work" procedure you are hearing about today but...

Guys...can someone suggest me a path to this thing?I searched a little on sciencemadness wiki and found that it can be made by reacting potassium plumbate with lead acetate.Potassium plumbate can be made with the hydroxide and lead dixode.But I don't have the dioxide so I need to make it(I was thinking about electrolysis with H2SO4,will it be good?) and neither the acetate.Should I make the acetate by reacting lead carbonate with acetic acid?And make the carbonate with the nitrate and sodium bicarbonate?

I need to start from very household things...The only "lead containing" thing I have is actual lead.

And about the HNO3.I would like to stay away from fuming acid if I can.Can good enough for this HNO3 be made by NO2 bubbling through water(nitrate+HCl+Cu) or should I stick with conc. H2SO4 and nitrate?

MeshPL - 27-9-2015 at 06:45

If you have good enough heat source, you can melt lead and bubble air through molten lead. Or pyrolyse lead carbonate or acetate. Or calcinate PbO. You can remove traces of PbO by washing with NaOH. I don't think you need ver specific temperature controll.

If you happen to have some H2O2 you can add it to acetic acid. That will react with lead. Otherwise acetic acid will react with lead very slowly, faster if you bubble air through. Nitric acid will dissolve it pretty well. You can technically use metal exchange and add lead to copper nitrate or acetate.

Pb is attacked by conc. HCl (Due to complex ion formation). Now the best part: you can dissolve Pb in conc. HCl, then neutralise it with NaOH and than add even more NaOH what will turn partially percipitated PbCl2 into Pb(OH)2. That's because lead chloride is slightly soluble in water while hydroxide is much more insoluble. Don't add too much NaOH or lead hydroxide will dissolve back!

Making PbO2 is tricky. Indeed you can cover lead with PbO2 by means of electrolysis. But it is not the best option. Cl2 will convert most lead compounds into PbO2, try dissolving lead (II) salt in water and make a chlorine generator from things available at pool supply stores.

I must say I've came across misLEADing informations regarding dissolving PbO2 in alkali. Some sourcess said it dissolves in aqueous alkali, some mentioned it can only be dissolved by molten hydroxides.

Also there is no reason you need acetate for your reaction. Nitrate should also work.

Tabun - 27-9-2015 at 06:56

Quote: Originally posted by MeshPL  
If you have good enough heat source, you can melt lead and bubble air through molten lead. Or pyrolyse lead carbonate or acetate. Or calcinate PbO. You can remove traces of PbO by washing with NaOH. I don't think you need ver specific temperature controll.

If you happen to have some H2O2 you can add it to acetic acid. That will react with lead. Otherwise acetic acid will react with lead very slowly, faster if you bubble air through. Nitric acid will dissolve it pretty well. You can technically use metal exchange and add lead to copper nitrate or acetate.

Pb is attacked by conc. HCl (Due to complex ion formation). Now the best part: you can dissolve Pb in conc. HCl, then neutralise it with NaOH and than add even more NaOH what will turn partially percipitated PbCl2 into Pb(OH)2. That's because lead chloride is slightly soluble in water while hydroxide is much more insoluble. Don't add too much NaOH or lead hydroxide will dissolve back!

Making PbO2 is tricky. Indeed you can cover lead with PbO2 by means of electrolysis. But it is not the best option. Cl2 will convert most lead compounds into PbO2, try dissolving lead (II) salt in water and make a chlorine generator from things available at pool supply stores.

I must say I've came across misLEADing informations regarding dissolving PbO2 in alkali. Some sourcess said it dissolves in aqueous alkali, some mentioned it can only be dissolved by molten hydroxides.

Also there is no reason you need acetate for your reaction. Nitrate should also work.

I will go for the lead-copper acetate.Do you have some usefull info on the potassium plumbate?

Amos - 27-9-2015 at 06:58

Quote: Originally posted by MeshPL  
If you have good enough heat source, you can melt lead and bubble air through molten lead. Or pyrolyse lead carbonate or acetate. Or calcinate PbO. You can remove traces of PbO by washing with NaOH. I don't think you need ver specific temperature controll.

If you happen to have some H2O2 you can add it to acetic acid. That will react with lead. Otherwise acetic acid will react with lead very slowly, faster if you bubble air through. Nitric acid will dissolve it pretty well. You can technically use metal exchange and add lead to copper nitrate or acetate.

Pb is attacked by conc. HCl (Due to complex ion formation). Now the best part: you can dissolve Pb in conc. HCl, then neutralise it with NaOH and than add even more NaOH what will turn partially percipitated PbCl2 into Pb(OH)2. That's because lead chloride is slightly soluble in water while hydroxide is much more insoluble. Don't add too much NaOH or lead hydroxide will dissolve back!

Making PbO2 is tricky. Indeed you can cover lead with PbO2 by means of electrolysis. But it is not the best option. Cl2 will convert most lead compounds into PbO2, try dissolving lead (II) salt in water and make a chlorine generator from things available at pool supply stores.

I must say I've came across misLEADing informations regarding dissolving PbO2 in alkali. Some sourcess said it dissolves in aqueous alkali, some mentioned it can only be dissolved by molten hydroxides.

Also there is no reason you need acetate for your reaction. Nitrate should also work.


Have you actually done any of what you're suggesting? It sounds like you're really just quoting wikipedia, which I'm sure the poster has already visited, considering that the procedure they're asking about is also found on the wiki page. Making this compound is not nearly as simple as wikipedia would have you believe.

MeshPL - 27-9-2015 at 07:28

I'm quoting wikipedia and at least 5 inorganic chemistry textbooks and basic knowledge and reasoning. Also I was interested in making my own Pb3O4. But... I didn't have mentioned heat source. Or good equipment to work with chlorine.:(

Also Georg Brauer's "Handbook of preparative inorganic chemistry" mentions the use of plumbate and plumbite together to make Pb3O4. And hypochlorite as oxidiser for making PbO2 (may be asier than using chlorine generator if it is actually available to you.)

And potasium plumbate... you can try finding it in that Brauer's handbook. I think it was posted somewhere on the forum.

[Edited on 27-9-2015 by MeshPL]

AJKOER - 30-9-2015 at 07:54

To prepare PbO2 reasonably quickly (which I have successfully performed a few years ago), first create Lead acetate by placing an excess of Pb (Lead solder was my source) in a mixture of vinegar and dilute H2O2 together with a touch of sea salt (a good electrolyte). Jump start the electrochemical reaction with a short burst in a microwave (cover with plastic wrap to avoid inhaling any Lead fumes). After an hour, with periodic reheating, you should have consumed the most of the vinegar and H2O2 having formed sufficient Lead acetate (in the amount of at most half the number of moles of acetic acid employed) to move on to the next step. The time frame is my estimate working with Cu and Fe, as originally, unaware of the underlying electrochemistry (no sea salt employed), the reaction proceeded slowly over a week. My take on the possible half reactions assuming similarity to the Zin-air battery (see https://en.m.wikipedia.org/wiki/Zinc%E2%80%93air_battery ), which in reality may not be precisely correct:

Anode: Pb + 2 OH- --> Pb(OH)2 + 2 e-

Cathode: H2O2 + 2 e- --> 2 OH-

Net cell: Pb + H2O2 --> Pb(OH)2

And, in the presence of acetic acid, HAc:

2 HAc + Pb(OH)2 --> PbAc2 + 2 H2O

Next step, to the aqueous Lead actetate, add chlorine bleach (NaClO). A white precipitate of Lead hypochlorite, Pb(ClO)2 forms which on mild heating is converted into red PbO2. Source, please see http://bcs.whfreeman.com/WebPub/Chemistry/ichem5e/Videos/Hyp... , to quote:

"Initially, lead(II) ion reacts with hypochlorite ion to give a white precipitate of lead(II) hypochlorite:

Pb2++(aq) + 2 ClO-(aq) --> Pb(ClO)2(s)

The lead(II) hypochlorite is then oxidized to lead(IV) oxide. Reaction is slow at room temperature but much faster when the tube is placed in boiling water.

Pb2+(aq) + 2 H2O(l) --> PbO2(s) + 4 H+(aq) + 2 e-
ClO-(aq) + 2 H+(aq) + 2 e- --> Cl-(aq) + H2O(l) "

[Edited on 30-9-2015 by AJKOER]

DalisAndy - 5-10-2015 at 21:10

I would assume you could use a process similar to Cherval's salt. Since some copper(II) is reduced to copper(I), since one electron is released when metabisulfite becomes sulfite. But that is an extreme extrapolation

[Edited on 6-10-2015 by DalisAndy]

DraconicAcid - 6-10-2015 at 06:45

That's lead(IV) oxide or lead dioxide.