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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: gxhfly on October 06, 2004, 09:34:49 AM

Title: who knows pearllman's catalyst?
Post by: gxhfly on October 06, 2004, 09:34:49 AM
I want to hydrogenate a compound having a nitro and a ketone group. I checked my lab and find a bottle of pearlman's catalyst. I wonder if it can be used to reduce that compound.  ??? I checked it in Google, but get less info as I wished. Can anyone help me here?
Title: Re:who knows pearllman's catalyst?
Post by: Demotivator on October 06, 2004, 09:51:34 AM
it's 20% Pd(OH)2 on Carbon.
It is normally used for hygrogenation of C-C double bonds.
Title: Re:who knows pearllman's catalyst?
Post by: gxhfly on October 06, 2004, 10:08:11 AM
Oh, thank you so much, demotivator! Then what method can i use to hydrogenate a nitro and ketone group to amine and ol together? ;)
Title: Re:who knows pearllman's catalyst?
Post by: Demotivator on October 06, 2004, 10:22:23 AM
it's fairly unselective. Though it hydrogenates C-C faster, It'll probably work for aromatic keto and nitro too.
But the reducing agent LiAlH4  is very unselective and therefore better. It will work for reducing keto and nitro group. And it does not require hydrogen gas.

http://www.chemicals.matthey.com/catalysts/introhet.asp
"Catalyst performance is determined mainly by the precious metal component. A metal is chosen based both on its ability to increase the rate of the reaction and its inability to complete an unwanted reaction. Palladium is typically the preferred metal for hydrogenation of acetylenes, olefins, carbonyls in aromatic aldehydes and ketones, aromatic and aliphatic nitro compounds, reductive alkylation, hydrogenolysis and hydrodehalogenation reactions. Platinum is typically the preferred metal for selective hydrogenation of halonitroaromatics and reductive alkylations.  Rhodium is used for the hydrogenation of aromatic rings and olefins while ruthenium is used for the hydrogenation of aromatic rings and aliphatic aldehydes and ketones."