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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: mir on September 03, 2006, 07:48:39 AM

Title: Removing colloidal Palladium
Post by: mir on September 03, 2006, 07:48:39 AM

Thanks for a great forum. I hope somone can help me with a problem:

I have done a synthesis with palladiumacetate in stochiometric amounts. All my palladium is probably reduced to palladium metal, since the reaction mixture is totally black with no visible residues. My friend told me this might be because the palladium is colloidal. The desired products is in high yield in the solution.

How do I remove this colloidal particles?

They wont go away, I tried to filtrate the mixture through celite with poor results.

Title: Re: Removing colloidal Palladium
Post by: Borek on September 03, 2006, 08:00:42 AM

Quote from: mir on September 03, 2006, 07:48:39 AM

How do I remove this colloidal particles?

I can be completely off, but in the presence of CN^- metallic palladium should be easily oxidized by almost everything.

Title: Re: Removing colloidal Palladium
Post by: mir on September 03, 2006, 08:25:28 AM

Quote from: Borek on September 03, 2006, 08:00:42 AM

I can be completely off, but in the presence of CN^- metallic palladium should be easily oxidized by almost everything.

The problem with the particles is that they also followed the organic layer with my products when I tried to extract it. Hm, maybe the palladium(0) is complexed with my product in some way. That would make it harder to remove it.

So I oxidize the palladium and then extract it from the mixture?
That might work. But with poor atom economy.

Title: Re: Removing colloidal Palladium
Post by: HP on September 03, 2006, 02:29:00 PM

Ultracentrofugation may help you to sediment Pd colloid also may try electrocoagulation or some chemical coagulation with some salt adding but as you have organic layer it could be problematic to some extend...

Title: Re: Removing colloidal Palladium
Post by: mir on September 04, 2006, 09:25:49 AM

I read an article, where they made it short and purified it all by flash chromatography. I wish there was another method for separating Pd(0), since flash is what the name say: Really fast, and in my ears: I wish I was an Octopus.

Title: Re: Removing colloidal Palladium
Post by: DrCMS on September 04, 2006, 10:55:52 AM

What you really need to use is Pd EnCat (Palladium Acetate encapsulated in a polyurea beads - avaliable in lab amounts from Aldrich) rather than Palladium Acetate.  You can just filter the beads off afterwards.

Title: Re: Removing colloidal Palladium
Post by: HP on September 04, 2006, 01:22:44 PM

Also Millipore sample filtration sounds reasonable for me...I agree and with mir about possible use flash chromatography purification.

Title: Re: Removing colloidal Palladium
Post by: mir on September 04, 2006, 03:17:14 PM

Quote from: HP on September 04, 2006, 01:22:44 PM

Also Millipore sample filtration sounds reasonable for me...I agree and with mir about possible use flash chromatography purification.

You mean the little syringes with build-in micrometer-filter?
Worth a try...