TheBlindGenius (Hive Bee)
03-07-03 04:49
No 414548
      Beaker's 2CB synthesis & Palladium/BaSO4  Bookmark   

I would have asked Beaker himself, but he hasn't posted since last year, so I don't think he's around anymore.  In his synthesis, ../rhodium/chemistry /2cb.beaker.html he does a catalytic transfer hydrogenation of 2,5-dimethoxynitroethane to 2C-H.  Does anyone know or care to give an opinon as to if 10% Pd/BaSO4 or 10% Pd/Al2O3 can be used instead of the 10% Pd/C he uses?

The working man is a sucker
 
 
 
 
    Barium
(Hive Addict)
03-07-03 09:10
No 414600
      Carrier  Bookmark   

By switching carrier one can change some of the properties of a catalyst completely. This is particulary so with Al2O3 since alumina can have acidic, neutral or alkaline properties. This means that instead of adding a base or acid one can get the right conditions just where the catalyst is and not everywhere in the solution.
Iīve wanted to investigate this phenomenon for some time to see if it can be used to catalytically hydrogenate nitrostyrenes to amines at low pressures with good yields.

But, to answer your question, I donīt know how Pd/BaSO4 behaves in this reaction since I havenīt used it. Pd/Al2O3 should work though.

Freaky
 
 
 
 
    hest
(Hive Adickt)
03-07-03 09:11
No 414602
      Pd  Bookmark   

Pd on BaSO4 is usual used iff you have some sulfur in the molecule, it's not as 'reactive' as pd/c but im's sure it works to reduce the NO2 group. Pd an Al-oxide react usual as Pd/c.
The short anser is it' dose't matter. (Im's sure they both are more ekspensive than Pd/C but who cares :-) ).
edit Ba was faster than mee. But should'n hee know abouth Pd on BaSO4 (laugh)
 
 
 
 
    Lilienthal
(Moderator)
03-12-03 11:46
No 416218
      As far as I know Pd on BaSO 4 is very ...  Bookmark   

As far as I know Pd on BaSO4 is very deactivated. What ever that means.
 
 
 
 
    algebra
(Stranger)
05-21-03 07:14
No 434549
      supported catalysts  Bookmark   

<edit>
I have not been able to find an answer to this question - is there any difference between 'palladium on carbon' and 'palladium on charcoal' or are these terms just synonymous? If these catalysts are different then in the context of catalytic transfer hydrogenation (CTH) with a hydrogen donor is there any preference for or against using one or the other.
 
 
 
 
    Lilienthal
(Moderator)
05-21-03 08:50
No 434568
      Both are the same. The abbreviation is Pd/C,...  Bookmark   

Both are the same. The abbreviation is Pd/C, some people call that palladium on carbon, others call  it palladium on charcoal.
 
 
 
 
    Tricky
(Stunning)
06-29-03 11:48
No 443331
      Help needed.  Bookmark   

Hi, bees!

I have the same problem as discussed in this topic.

Swit would like to try the Pd-reduction rxn of ring-substituted phenyl-2-nitroethanes , but he can't pick out the right catalyst.
Please, prompt him in this holy affair  smile!

I have the next choice (from Sigma-Aldrich catalogue):
1) 10% Pd on activated aluminia (hydrogenation catalyst).
2) 10% Pd on activated charcoal (there is no notes, what is it... ) - so, it borns some doubts (as a matter of fact I've posted my question about it here) ...
3) 10% Pd on barium sulfate (hydrogenation catalyst).
4) 10% Pd on calcium carbonate (hydrogenation catalyst).

Tanx for advice.

AllAccess
 
 
 
 
    Rhodium
(Chief Bee)
06-30-03 07:01
No 443525
      palladium on activated charcoal = Pd/C  Bookmark   

You are looking for #2 - the one with palladium on activated charcoal. That one is 10% Pd/C. On the other supports - alumina/barium sulfate/etc - the Pd has differing reactivities, so avoid those if you don't know what you are doing.

The reason the catalog doesn't explicitly state "hydrogenation catalyst" for that one is probably because Pd/C has a lot of other different uses.