R.Esposito
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Registered: 1-6-2012
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How to clean Pd/C with Raney after hydrogenation?
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...
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solo
International Hazard
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Registered: 9-12-2002
Location: Estados Unidos de La Republica Mexicana
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Mood: ....getting old and drowning in a sea of knowledge
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Method for platinum or palladium catalyst reactivation
United States Patent 4120819
Attachment: Method for platinum or palladium catalyst reactivation .pdf (182kB)
This file has been downloaded 452 times
It's better to die on your feet, than live on your knees....Emiliano Zapata.
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zed
International Hazard
Posts: 2278
Registered: 6-9-2008
Location: Great State of Jefferson, City of Portland
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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]
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