feynmann
Harmless
Posts: 29
Registered: 6-8-2008
Member Is Offline
Mood: No Mood
|
|
Palladium on charcoal Nope question
I have 20 gm of the ALdrich palladium on charcoal 5 percent .
I want to know how to regenerate the metal in the form of palladium chloride after the reaction is over .
I would like to know if someone tried it and what is the result?
I wonder if I can use the method of platinum regeneration by dissolving in aqua regia and evaporating till dryness with conc HCl several times
|
|
|
Klute
International Hazard
Posts: 1378
Registered: 18-10-2006
Location: France
Member Is Offline
Mood: No Mood
|
|
Why go by PdCL? Dilter the catalyst off, wash it well with a solvent, 10% NaOh, water, dry and re-use!
I fyou want PdCl2, you better buy it then make it from Pd/C!
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
|
|
|
feynmann
Harmless
Posts: 29
Registered: 6-8-2008
Member Is Offline
Mood: No Mood
|
|
Sorry what I want to is to regenerate Pd/c after usage to use again
I thought that obtaining PdCl2 is the only method as Pdcl2 is used to prepare Pd/C according to vogel
|
|
|
DJF90
International Hazard
Posts: 2266
Registered: 15-12-2007
Location: At the bench
Member Is Offline
Mood: No Mood
|
|
To prepare it, yes it is a viable option. But once you already have the palladium metal adsorbed (is this the correct term?) onto the carbon then
there is no need to strip it off and then re-adsorb it... Just wash as Klute says!
|
|
|
Klute
International Hazard
Posts: 1378
Registered: 18-10-2006
Location: France
Member Is Offline
Mood: No Mood
|
|
Have a look at US 3,214,385 for details on properly re-activating Pd/C for extended re-use (up to 20 with only 6% decrease in yield for hydrogenation
of succinic acid)
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
|
|
|
feynmann
Harmless
Posts: 29
Registered: 6-8-2008
Member Is Offline
Mood: No Mood
|
|
I also found a patent to regenerate Pdcl2 as it is the precursor for many other catalysts
US3210152
I wonder if there is any simpler method for regeneration of pdcl2 like that used for platinum regeneration
Procedure for platinum regenration
Platinum residues from hydrogenation reactions should be carefully preserved and subsequently recovered by conversion into ammonium chloroplatinate by
the following method. Dissolve the platinum or platinum residues in aqua regia, evaporate just to dryness several times with concentrated hydrochloric
acid, dissolve the final residue in a little water and filter. Precipitate ammonium chloroplatinate from the filtrate by addition of excess of a
saturated solution of ammonium chloride. Filter and dry the precipitate at 100°C.
|
|
|
DJF90
International Hazard
Posts: 2266
Registered: 15-12-2007
Location: At the bench
Member Is Offline
Mood: No Mood
|
|
So you mean that rather than strip the Pd off of the charcoal and re-adsorb it, you're talking about recovering the (very) small amount of Pd that
gets leached into the reaction mixture? This is important, as although only a very small amount of Pd is lost each time, eventually you say bye bye to
your palladium 
|
|
|
stoichiometric_steve
National Hazard
Posts: 819
Registered: 14-12-2005
Member Is Offline
Mood: satyric
|
|
i think the thread originator has no idea what you two are talking about.
|
|
|
feynmann
Harmless
Posts: 29
Registered: 6-8-2008
Member Is Offline
Mood: No Mood
|
|
why are u saying so???
I have been doing so for many years ....just wanna additional experience
[Edited on 8-8-2008 by feynmann]
|
|
|
JohnWW
International Hazard
Posts: 2849
Registered: 27-7-2004
Location: New Zealand
Member Is Offline
Mood: No Mood
|
|
The scarcity and value of Pd and Pt is also a good reason for determining whether cheaper metallic catalysts, particularly Ni, could be used for the
same purpose instead.
|
|
|
Klute
International Hazard
Posts: 1378
Registered: 18-10-2006
Location: France
Member Is Offline
Mood: No Mood
|
|
Totally agreed, copper seems like a very promising candidate too. Ni oftenr equires high temp and pressures, even though some CTH can go one well
enough. But thta's not on the threads' topic unfortuanly 
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
|
|
|
S.C. Wack
bibliomaster
Posts: 2419
Registered: 7-5-2004
Location: Cornworld, Central USA
Member Is Offline
Mood: Enhanced
|
|
Just thought that I'd point out, and here is as good as anywhere to do so and you might not be aware, that the price of Pd has been falling
precipitously in the past month, if anyone has priced Pd and been scared away in the past year. It's falling pretty fast now and on its way to losing
50% of its value in 6 months.
http://www.kitco.com/charts/livepalladium.html
If it goes back down to $200, it's time to mortgage the house and back up the truck. I last bought from Apmex, once in a while they will have a Maple
or a bar within $10-20 of spot. They don't last long when that happens, because that is as good as it gets for Pd coin or bar; they often are out of
stock when prices fall (esp. silver prices, large bars from them or Tulving may be available though.) or they charge a high premium over spot.
[Edited on 12-8-2008 by S.C. Wack]
|
|
|
starman
Hazard to Others
Posts: 318
Registered: 5-7-2008
Location: Western Australia
Member Is Offline
Mood: No Mood
|
|
Recently purchased a few grams of palladium form ebay.It is in the form of small chunks of jewelers scrap,was hoping to turn it into something usable
and have a few questions if anyone has time.
The (limited) information I have viewed states Pd dissolves slowly in HCl. What are we looking at hours? weeks?
Also are there altenatives to formaldehyde or the nitric acid wash for the Pd/C preparation as given in org synth? Does it have to be nitric
acid?
Basically looking for a much as possible OTC for getting a finley divided metal on support of some sort.
Any suggestions much appreciated.
|
|
|
not_important
International Hazard
Posts: 3873
Registered: 21-7-2006
Member Is Offline
Mood: No Mood
|
|
The dissolution of palladium in non-oxidising acids (ie HCl) requires the addition of an oxidising agent. Air will work, but it is much faster to use
elemental chlorine or bromine. Alternatively you could slowly add NaNO3 or KNO3 to the hydrochloric acid - palladium mixture.
.
|
|
|
Klute
International Hazard
Posts: 1378
Registered: 18-10-2006
Location: France
Member Is Offline
Mood: No Mood
|
|
You can use NaBH4 IIRC to reduce the salts to metal, but if you can't get formaldehyde..
In the platinium mirroir thread, it was suggested dissolving Pt metal by electroslyis in HCl, maybe this could work with Pd?
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
|
|
|
cnidocyte
Hazard to Others
Posts: 214
Registered: 7-7-2010
Member Is Offline
Mood: No Mood
|
|
I wanna make some of this from palladium metal. I know I could dissolve Pd with aqua regia but would there be a better way to oxidise the Pd if my aim
is to turn it into PdCl2.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
