Author Topic: pseudo and CHCl3  (Read 3938 times)

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Osmium

  • Guest
pseudo and CHCl3
« on: May 24, 2004, 03:39:00 PM »
Can anyone comment from first hand experience on the solubility of pseudoephedrine hydrochoride in chloroform? or quote some reliable literature value?
The search engine gives conflicting results. Several quotes from the Merck index can be found, either saying that pseudo HCl is "soluble" in CHCl3, or that solubility is only 0.011g/ml.


wareami

  • Guest
Merck verus ???
« Reply #1 on: May 24, 2004, 04:29:00 PM »
Os: I'd be more inclined to trust the Merck's latest entry's but here is some data from 1953 that states Pseudoephedrine hcl is soluble in chloroform.


Physical Properties of Pseudoephedrine (d-Ephedrine)
   Manske & Holmes, The Alkaloids, Vol III, p 347, Academic Press (1953)
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The base forms white rhombic crystals, mp 118°C (from water) and is much
less soluble in water than ephedrine. Hydrochloride, colorless needles,
mp 181-182°C, the salt is soluble in chloroform. Hydriodide, rhombic
crystals, mp 172°C (43).

l-pseudo-Ephedrine has not been found in nature. The base has mp 118-118.7°C.
The hydrochloride has mp 182-182.5°C. The l-pseudo-ephedrine-d-tartrate has
mp 178°C; l-pseudo-ephedrine-l-tartrate, mp 178.5°C (17, 68, 69, 70).

dl-pseudo-Ephedrine (racemic pseudo-ephedrine) melts at 118°C.
The hydrochloride has a mp of 164°C.


http://www.ephedra.demon.nl/stories/chemical.htm




fierceness

  • Guest
Re: DESCRIPTION AND SOLUBILITY : FINE, WHITE...
« Reply #2 on: May 25, 2004, 12:01:00 AM »


DESCRIPTION AND SOLUBILITY :

FINE, WHITE TO OFF-WHITE CRYSTALLINE OR POWDER. HAVING A FAINT CHARACTERISTIC ODOR. VERY SOLUBLE IN WATER; FREELY SOLUBLE IN ALCOHOL; SPARINGLY SOLUBLE IN CHLOROFORM. MELTING POINT : 182--186 C.



http://www.gsmeheco.com/english/yansuanweimahuangjian.htm



Rhodium

  • Guest
No exact answer, but a lower solubility limit...
« Reply #3 on: May 25, 2004, 01:15:00 AM »
Emde tells us that (+)-Pseudoephedrine·HCl is "several times more soluble" than (-)-Ephedrine·HCl in water, abs. ethanol, chloroform and ether.

He then lists the following solubility ratios (presumably w/w) for (-)-Ephedrine·HCl in various solvents at their respective boiling point and at room temp.

Water: 1:1 - 1:5 (RT)
Abs. EtOH: 1:9 - 1:28 (RT)
Chloroform: 1:2000 - 1:3000 (RT)
Ether: Insoluble

Ref:

Post 401416

(Rhodium: "Hermann Emde's Ephedrine Chemistry Treatise", Stimulants)



WizardX

  • Guest
crystal lattice
« Reply #4 on: May 25, 2004, 07:39:00 AM »
You also must take into account the water content in the (+)-Pseudoephedrine·HCl crystal lattice. Dry (+)-Pseudoephedrine·HCl is slightly more soluble in chloroform than (+)-Pseudoephedrine·HCl hydrate.

This must be taken into consideration as well as temperature and pressure as referred by Emde.


He then lists the following solubility ratios (presumably w/w) for (-)-Ephedrine·HCl in various solvents at their respective boiling point and at room temp.