urushibara (Hive Bee)
06-28-03 18:34
No 443198
      for those who think ephedrine is better  Bookmark   

here's an excerpt of something from rhodium about isomerising ephedrine/pseudoephedrine

On heating ephedrine hydrochloride with 5% hydrochloric acid, under pressure, at 170-180C (248) or with 25% acid, at 100C, the compound is partially converted to pseudo-ephedrine (20, 32, 40). The conversion is reversible and an equilibrium is established. According to Emde (39), the rearrangement takes place by replacement of the hydroxyl group by chlorine, followed by hydrolysis. Oxidation of ephedrine or pseudo-ephedrine, gives benzaldehyde or benzoic acid.

so you can get 50% ephedrine out of pseudo if you think it's worth it

you can't keep peace with a gun
(Chief Bee)
06-28-03 21:58
No 443217
      H. Emde, Helv Chim Acta, 12, 365-405 (1929)  Bookmark   

The original reference is here, for those of you who can read German: Post 401416 (Rhodium: "Hermann Emde's Ephedrine Chemistry Treatise", Stimulants)