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Author: Subject: Pd/C vs. Pd/BaSO4
stoichiometric_steve
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[*] posted on 3-2-2008 at 04:55
Pd/C vs. Pd/BaSO4


does anybody know if the difference on the solid support of Pd results in different activity or applicability for certain reductions? as far as specific area per gram matters, charcoal sure makes a difference vs. BaSO4.
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Klute
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[*] posted on 3-2-2008 at 06:02


It's not much, but in Chemical Reviews, (1985) 85(2), 129-170 they state:

" [the following] order of activity was found in the hydrogenolysis of benzyloxycarbonyl and benzyl protecting groups of peptides using cyclohexadiene as hydrogen donor, Ie., Pd black > 10%
Pd/C > 5% Pd/C > 10% Pd/BaS04 > 5% Pd/BaSO4."

ref provided: Felix, A. M.; Heimer, E. P.; Lambros, T. J.; Tzougraki, C.; Meienhofer, J. J. Org. Chem. 1978, 43, 4194.
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vulture
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[*] posted on 3-2-2008 at 09:26


Pd/BaSO4 will not reduce double bonds, but will reduce triple bonds, IIRC. It's basically Pd poisoned with Ba.



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[*] posted on 3-2-2008 at 09:31


.......see Rylander book on Hydrogenations there is lots of info there....solo



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Nicodem
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[*] posted on 3-2-2008 at 13:16


Pd/BaSO4 is a slightly poisoned form of Pd catalyst that has some peculiar properties. For example, it can reduce acyl chlorides to aldehydes but not aldehydes to alcohols (not that Pd/C is particularly efficient at reducing aldehydes either, but Pd/BaSO4 does it more cleanly).
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[*] posted on 3-2-2008 at 15:10


PALLADIUM CATALYSTS http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0685



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chemrox
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[*] posted on 3-2-2008 at 18:28


Quote:
Originally posted by Klute
It's not much, but in Chemical Reviews, (1985) 85(2), 129-170 they state:

" [the following] order of activity was found in the hydrogenolysis of benzyloxycarbonyl and benzyl protecting groups of peptides using cyclohexadiene as hydrogen donor, Ie., Pd black > 10%
Pd/C > 5% Pd/C > 10% Pd/BaS04 > 5% Pd/BaSO4."

ref provided: Felix, A. M.; Heimer, E. P.; Lambros, T. J.; Tzougraki, C.; Meienhofer, J. J. Org. Chem. 1978, 43, 4194.


I don't quite see the applicability of this paper but here it is:

Attachment: jo00415a045.pdf (371kB)
This file has been downloaded 1636 times





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