lab_bitch (Hive Bee)
07-02-03 22:27
No 444145
      What Psuedo Impurities Affect Cat. Hydrogenation?  Bookmark   

Does anyone know the particular denaturants in store bought psuedo that would poison Pt/C or Pd/C catalysts if one wanted to hydrogenate it?  Has anyone actually tried to hydrogenate store bought psuedo or is it just assumed that it is too impure to use?  Are there any OTC sources of ephedrine/psuedo that would be suitable for hydrogenation?
(Hive Bee)
07-03-03 11:47
No 444279
      I'm not talking about throwing whole pills in.  Bookmark   

I'm not talking about throwing whole pills in.  Many people have said that sudafed will not work for hydrogenations, even after thoroughly cleaning them.  In other words, there are compounds in the pills that will poison the catalyst even in very minute quantities.  After reading the ingrediants on the box, I didn't see anything that would seem capable of poisoning the catalyst.  All I want to know is if anyone has actually run straight E and sudafed in the exact same rxn with the results being that the E worked fine but the sudafed didn't.
07-03-03 23:58
No 444430
      plain forget it  Bookmark   

you have neither the theoretical nor practical knowledge to get this going even with SIGMA-ALDRICH material.
Btw. Ephedrine is a chemical but sudafed is the name of a brand.

Didnīt answer your question....
but now I did.

Honi soit qui mal y pense
07-04-03 11:01
      Watch What You Say Ragnaroekk
(Rated as: offending)
07-04-03 19:50
No 444612
      On Rhodiums page  Bookmark   

the one who is interested in catalytic hydrogenation finds:
../rhodium/pdf /poisoning_and_deactivation.pdf

and more.

Reading this highly interesting article prevents from asking questions like those asked in this thread at start - provided that one understands what is written.

I am to lazy to
- explain why the questions have been not on the point
- explain how the right questions would have looked like
- and to answer these questions .

Not for someone with this special attitude. smile
Would be wasted time anyways.

Honi soit qui mal y pense
(Hive Bee)
07-04-03 23:08
No 444642
      Come on! Don't you think that you would have a  Bookmark   

Come on! Don't you think that you would have a "special attitude" too if someone told you that you don't know anything about hydrogenation?  By the way, I didn't really expect anyone to know exactly what impurities deactivate the catalyst.  I mainly wanted to know if anyone had successfully hydrogenated perfectly cleaned store bought pills before.  When I UTFSE, I found people who said that it wouldn't work, but they didn't say whether they had tried it themselves, or whether it was just speculation.  If you actually know the answer to my question like you say you do, then post it for everyone's benefit.  Otherwise, don't go around insulting people for no reason at all.  I'm glad you're post wasn't deleted as well because it makes you look like a jackass.
(Hive Bee)
07-05-03 11:27
No 444723
      RE: What Pseudo Impurities affect....  Bookmark   

If you are going the way of first making chloroephedrine or chloro pseudo ephedrine and then Hydrogenationg with Pd/charcoal, my experience has been that once cleaned you need to wash your chloroephedrien or chloropseudo ephedrine well with acetone then dry , then follow with  the hydrogenation procedure . You may still poison your catalyst, so what happens  is recharge with fresh catalyst and save the poisoned catalyst to later wash and reactivate. Since  thionylchloride was used to make the halogenated ephedrine(pseudo ephedrine), care must be taken to remove all the junk in the ether or acetone wash till precipitated product is white........the whiter the smoother your run and the faster it takes the

We're  all in this world together,