stoichiometric_steve
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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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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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Pd/BaSO4 will not reduce double bonds, but will reduce triple bonds, IIRC. It's basically Pd poisoned with Ba.
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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solo
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.......see Rylander book on Hydrogenations there is lots of info there....solo
It's better to die on your feet, than live on your knees....Emiliano Zapata.
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Nicodem
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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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WizardX
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PALLADIUM CATALYSTS http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0685
Albert Einstein - \"Great ideas often receive violent opposition from mediocre minds.\"
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chemrox
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| 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.
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I don't quite see the applicability of this paper but here it is:
Attachment: jo00415a045.pdf (371kB)
This file has been downloaded 1750 times
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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