cheeseboy (Hive Bee)
02-05-02 19:24
No 265538
      TLC separations  Bookmark   

  Osmium said that the re-arrangement of 2-phenylpropanol to phenylacetone is only possible using TLC (thin layer chromatography). Due to Hydrotropic Aldehyde having a very close BP temp. to P2P. Now, cheese thought that after the rxn took place in -15*C, one could just extract the P2P with ether or toluene or whatever non-polar you want.
  Or would the the Hydratropaldehyde go into the non-polar as well? This seems very challenging the more cheese thinks about it. Ephedrine reduction is so much more direct, in  a sense that no intermediates like "p2p" need bee made, it's just one reduction of ephedrine via HI.

May The Source Bee With You....Always.

  - OB1KNoBee
(Stoni's sexual toy)
02-05-02 22:49
No 265602
      Re: TLC separations  Bookmark   

What I meant was that you have to follow the progress of the reaction with TLC, so you won't stop the reaction too early, since there is no easy way to separate the two.

Now that I think about it, maybe excess unconverted hydratopic aldehyde can be oxidised to the acid (autoxidation by air even?) and extracted with a base.
That might work.

I'm not fat just horizontally disproportionate.
(Hive Prodigy)
02-05-02 23:06
No 265610
      Re: TLC separations  Bookmark   

That is exactly what Rhodium had suggested to me awhile back for seperation of the two. If it is the only way, it is truly a sad situation, as you can imagine. The destruction of any unreacted precursor just to salvage product from the reaction mixture, is synonymous with ruthless genocide.


Vivent Longtemps la Ruche!