solubility and insolubility of ephedrine/psuedoephedrine

[Le Junk]

Does anyone know what ephedrine hydrochloride/ psuedoephedrine are soluble in the cocaine hydrochloride is not, or vica versa?

Greatly appreciated.

Le Junk

[redeemer]

You probably aren't going to find a solvent that won't dissolve at least some of each compound as they are both hydrochloride salts. Merck says cocaine hydrochloride is soluble in acetone, it doesn't mention whether (pseudo)ephedrine hydrochloride is, although it probably is to some extent.

[Sandbag]

Cocaine is not soluble in acetone. I've used it to wash blow before and the remaining solid was definately cocaine. In answer to the question I'm not sure if there's a certain solvent that will dissolve eph/peph but not cocaine, but I think if you just recrystallize the cocaine by dissolving the coke in de-ionized H20, titrating with NH3, extracting freebase with ether and then bubbling HCl gas through the ether to reform CocHCl and harvest. Though this is pending on the assumption that eph/pse won't be affected by the NH3 and will remain in the aqueous layer when the Coc- is extracted with ether.

[Kremar]

Cocaine
pKa (15°) 8.61

Base:
One gram dissolves in 600 ml water, 270 ml water at 80°, 6.5 ml alcohol, 0.7 ml chloroform, 3.5 ml ether, 12 ml oil turpentine, 12 ml olive oil, 30-50 ml liquid petrolatum. Also sol in acetone, ethyl acetate, carbon disulfide.

HCl:
One gram dissolves in 0.4 ml water; 3.2 ml cold, 2 ml hot alcohol; 12.5 ml chloroform. Also sol in glycerol, acetone. Insol in ether or oils.

Pseudo
pKa 9.22

Base:
Sparingly sol in water. Freely sol in alc or ether.

HCl:
(at 25° ) One gram dissolves in 0.5ml water; 90.9ml chloroform; 3.6ml ethanol.

Eph
Base:
Sol in water, alcohol, chloroform, ether.

HCl:
Freely sol in water; sol in alcohol. Practically insol in ether.

as you can see, their pKa are too close to eachother, so you wont be able to separate them through an A/B exctraction as someone above suggested...

[redeemer]

You could try a recrystallization of the freebased powder from water followed by a conversion to the HCl salt and and wash with chloroform. The first step should remove the ephedrine while the latter should remove the pseudoephedrine, though the chloroform will also disssolve some cocaine.

[alkap555]

do an Acetone wash (caffeine gone)
then freebase
wash the bases with water (ephedrine gone)
dry completely
sal out of acetone using 1:1 HCL/ethanol
do final acetone wash

Why do you predict that an aqueous wash of freebase cocaine and ephedrine (in say DCM or Et2O) will selectively pull out the ephedrine? These are both amines with similar solubility profiles (gut feeling--too lazy to look up anything).

[sekio]

Ephedrine freebase isn't very water soluble, dude.

[jammon]

[sekio]

That is one page of two - and I don't know how far I would trust it given it is from a clandestine cocaine purification handbook from the 70s.

Apparently ephedrine base is actually soluble 1g in 20ml water or 0,2 ml ethanol. Pseudo-ephedrine is less. The salt is still more soluble of course but I guess the a-hydroxyamine is enough of a hydrogen bond buffet that it can solvate ok. Don't know if you would call ephedrine a strong base though, it doesn't disproportionate to OH- and ephedryl(??) ions. NaOH on the other hand is a strong base.


For others who are wondering "WTF is cocamine" - cinnamoylcocaine apparently.

[sekio]

Read my post?

Technically can you not just freebase, and wash it with tons of water to remove essentially all the impurities, then re-xtallize from whatever you please?