chemrox
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palladium sponge
what is palladium sponge? I need palladium acetate and I have PdCl2 and Pd/C. The procedure I have for making Pd acetate is via Pd sponge.
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mr.crow
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Would a nitric acid/acetic acid solution work? I have shown how vigorously normal aqua regia attacks palladium coins, I don't think sponge is needed
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smuv
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probably palladium sponge = palladium black; just finely divided Pd. If this is not the case, then I am sure any finely divided Pd source should
easily substitute. It may also be possible to simply substitute PdCl2 for whatever you want to do or make the acetate via metathesis of the
chloride...
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DDTea
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I imagine it's the Palladium equivalent of Raney nickel, which was the first "sponge metal" catalyst for organic reductions.
"In the end the proud scientist or philosopher who cannot be bothered to make his thought accessible has no choice but to retire to the heights in
which dwell the Great Misunderstood and the Great Ignored, there to rail in Olympic superiority at the folly of mankind." - Reginald Kapp.
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Fleaker
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Quote: Originally posted by mr.crow  | | Would a nitric acid/acetic acid solution work? I have shown how vigorously normal aqua regia attacks palladium coins, I don't think sponge is needed
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Nitric and acetic acids should never be mixed or refluxed if concentrated!! That wikipedia article which gave you that idea is slightly misinformed.
Also, palladium sponge is not the same as palladium black. Palladium black is prepared by reduction of chloropallidic acid (H2PdCl6) with ammonium
formate or borohydride. Palladium sponge is prepared by reduction of any palladium salt with hydrazine, or by heating (NH4)2PdCl6, a brick-red
compound, until it gives off ammonium chloride and chlorine gas. What's left behind is a gray sponge that settles easily if put in water. The same
holds true for rhodium, platinum, and the rest of the sisters.
The activities are wildly different--palladium black holds hydrogen quite well--in fact, palladium blacks I have made must be heated in vacuo to
completely remove the hydrogen stuck onto them.
If one wants palladium acetate, one should start from palladium black and place it in refluxing glacial acetic acid and then cautiously add oxidizer.
Alternatively, make the complex nitrate with a slight excess of Pd present, and reflux that with GAA until no more brown fumes are present. The
solution will be a vivid orange-red that is yellow on dilution.
@Chemrox
PdCl2 can be used in lieu of the acetate in many catalytic reactions.
Alternatively, I may have some Pd(OAc)2 to spare you.
Neither flask nor beaker.
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hkparker
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Just curious, but why not?
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Fleaker
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Oxidation/Reduction.
Technically, you're not supposed to store GAA and 16M or greater HNO3 in the same acid cabinet.
Neither flask nor beaker.
"Kid, you don't even know just what you don't know. "
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entropy51
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| Quote: Originally posted by chemrox | | what is palladium sponge? I need palladium acetate and I have PdCl2 and Pd/C. The procedure I have for making Pd acetate is via Pd sponge.
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The Pt sponge that I have made resembles granules of aquarium filter charcoal or black pumice stone. It
seems to be a more active catalyst than Pt black. There are recipes for its preparation in the old journals. Also see Platinum black.
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chemrox
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@Fleaker- thank you my friend! Most particularly for the answer to my question. Also for the Pd(Oac)2 you can spare (if any).
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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