Sciencemadness Discussion Board

How to clean Pd/C with Raney after hydrogenation?

R.Esposito - 28-11-2012 at 05:19

Hi all. I have problem with catalyst after reaction under 30bar. At the end of hydrogenation catalyst I extract it out and washed several times with demineralized water and finally with methanol. Optically pure catalyst appears, but at each use it is obvious that the hydrogenation does not behave as before. As if it could not clean the catalyst or that lost power...

solo - 28-11-2012 at 06:01

Method for platinum or palladium catalyst reactivation
United States Patent 4120819

Attachment: Method for platinum or palladium catalyst reactivation .pdf (182kB)
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zed - 28-11-2012 at 18:53

Many catalysts have a limited life expectancy. In the case of Pd and Pt, hydrogenation catalysts, generally after few runs, they become poisoned, lose activity, and have to be reactivated or completely recycled.

Active sites upon the catalyst's surface become crudded-up and blocked, and are thus unavailable to work their magic. Additionally, some common solvents are capable of poisoning or deactivating catalysts.

Reactivation usually cannot be practiced eternally. Eventually, catalysts completely lose their mojo, and the Pt or Pd content is dissolved into aqua regia, and from the recovered metal salts...fresh new catalyst can be generated.

[Edited on 29-11-2012 by zed]