# Palladium Acetate - Did anyone try?



## Alentia (Nov 14, 2013)

I have found this interesting note from wiki:



> Pd(NO3)2 + 2 CH3COOH → Pd(O2CCH3)2 + 2 HNO3
> 
> When warmed with alcohols, or on prolonged boiling with other solvents, palladium(II) acetate decomposes to palladium.



You suppose to get brown-yellow salt precipitate (or not.)

Based on this, if palladium was present during HNO3 treatment, after separating Ag with NaCl or HCl process can continue to separate Pd from the solution.

I remember that AgNO3 is not very friendly with Acetic Acid.

Cu, Zn, Ni nitrates do not suppose to react with CH3COOH.


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## freechemist (Nov 18, 2013)

As I wrote in my answer to 9kuuby9's last question in _"Final refining gold, - brainstorming"_
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=19424&start=40#p198614
it is not possible, to separate Ag and Pd, dissolved in nitric acid, without using an excess of chloride (NaCl or HCl), such as to *precipitate AgCl quantitatively and, at the same time, forming chloro-complexes of Pd ([PdCl4]2-)* quantitatively. The Pd will remain in solution as the chloro-complex [PdCl4]2- mainly, which will not react with acetic acid.


last edited by freechemist, november, 18, 2013, 19:26


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## Alentia (Nov 19, 2013)

Thank you!

1. Adding Acetic Acid to Silver/Palladium Nitrate should precipitate Pd Acetate, is it correct?

2. If Na present in the solution, will it create Na(ac) to subsequently react with Ag(NO3)2 to create Ag(ac)?

3. 10gr of Ag(ac) is soluble in 1000ml of water. The question will remain, how to convert dissolved Ag(ac) to elemental Ag if #2 is correct?

This goes back to Harold's mentioning of separating Pd from cell slime using NaCl or HCl to drop silver and than cement Pd. But if Pd will become chloride almost insoluble in water with either, it will mix with AgCl2 again unless excess of HCl is added. Or treating both Chlorides with HCl to dissolve Pd before converting Ag elemental with Al/HCl.


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## freechemist (Nov 19, 2013)

> 1. Adding Acetic Acid to Silver/Palladium Nitrate should precipitate Pd Acetate, is it correct?


This is not correct. Nothing will precipitate. The resulting solution will contain silver-cations, Ag+, Pd-cations, Pd2+, nitrate-anions, NO3-, some in digestion of silver/palladium unused nitric acid, HNO3, plus the added amount of acetic acid.



> 2. If Na present in the solution, will it create Na(ac) to subsequently react with Ag (NO3)2 to create Ag(ac)?


If sodium is present, it will remain dissolved as sodium-cation, Na+, as it was before, and it does not react with any of the dissolved or to be additionally dissolved substances.
The chemical formula for silver nitrate is AgNO3. The salt is composed of singly positively charged silver-cations, Ag+ and an equal amount of singly negatively charged nitrate-anions, NO3-.
Silver acetate, Ag(ac) will only precipitate, if acetic acid has been added to the original silver/palladium-solution, and if the resulting solutions pH is increased sufficiently, to allow significant amounts of acetate-anions, (ac)- to be formed.



> This goes back to Harold's mentioning of separating Pd from cell slime using NaCl or HCl to drop silver and than cement Pd. But if Pd will become chloride almost insoluble in water with either, it will mix with AgCl2 again unless excess of HCl is added. Or treating both Chlorides with HCl to dissolve Pd before converting Ag elemental with Al/HCl.


As mentioned in my former post, it is not possible, to precipitate only silver chloride, AgCl, selectively by means of HCl or NaCl from mixed silver/palladium-solutions in aqueous HNO3, without forming soluble [PdCl4]2--anions at the same time. However, if enough chloride has been added, AgCl can be recovered simply by filtration, leaving behind a filtrate without silver, containing the remaining palladium dissolved as [PdCl4]2-.


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## Lou (Nov 19, 2013)

Mind you that the silver chloride will tenaciously hold palladium values present; so when the chloride is smelted, the resulting silver bar must be analyzed for Pd content (best with AA).

Lou


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## Alentia (Nov 19, 2013)

freechemist said:


> > > This goes back to Harold's mentioning of separating Pd from cell slime using NaCl or HCl to drop silver and than cement Pd. But if Pd will become chloride almost insoluble in water with either, it will mix with AgCl2 again unless excess of HCl is added. Or treating both Chlorides with HCl to dissolve Pd before converting Ag elemental with Al/HCl.
> >
> >
> > As mentioned in my former post, it is not possible, to precipitate only silver chloride, AgCl, selectively by means of HCl or NaCl from mixed silver/palladium-solutions in aqueous HNO3, without forming soluble [PdCl4]2--anions at the same time. However, if enough chloride has been added, AgCl can be recovered simply by filtration, leaving behind a filtrate without silver, containing the remaining palladium dissolved as [PdCl4]2-.



To confirm I understood you correctly with additional questions:

1. (PdCl4)2 will be soluble in Nitrate Solution and either filtration or decanting will separate Ag from Pd with traces of Pd remaining in the chloride(aq), no matter how good it is washed.
2. Does above holds true for NaCl or HCl or both?
3. Is it possible to cement (PdCl4)2 subsequently with copper (for "dirty" Pd) or should "standard" process to be utilized to recover palladium?
4. How one would determine "enough chloride has been added"?


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## Lou (Nov 19, 2013)

1. (PdCl4)2 will be soluble in Nitrate Solution and either filtration or decanting will separate Ag from Pd with traces of Pd remaining in the chloride(aq), no matter how good it is washed.
[PdCl4]2- will remain absorbed onto the surface of the AgCl. Although washing with a dilute (0.5 M) HNO3 solution will largely remove all but a few tenths of a percent. 
2. Does above holds true for NaCl or HCl or both? Yes. Both are chloride sources.
3. Is it possible to cement (PdCl4)2 subsequently with copper (for "dirty" Pd) or should "standard" process to be utilized to recover palladium?
No, because you have a gross excess of nitric acid; it would be very noxious to try and use this; better to neutralize the solution (perhaps pH 7-8) and recover the Pd as its hydroxide (this can be re-dissolved in minimum HCl), and perhaps finish by making PdS. 
4. How one would determine "enough chloride has been added"?
Know the silver concentration (titration with chloride, Volhard can't be used because Pd interferes). You need not add a gross excess of Cl- (which will also solublize some of the AgCl as [AgCl2]-


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## Lino1406 (Dec 22, 2013)

If it helps - Palladium acetate is easily melted directly to Pd


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