Author Topic: possible azeotrope Meam/X ?  (Read 1506 times)

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zig

  • Guest
possible azeotrope Meam/X ?
« on: August 21, 2003, 10:00:00 PM »
When MDMA is produced with MeAm gas and MDP2P a tricky part of the reaction is how to get the proper amount of MeAm gas into the solution. The article by LaBTop was followed but a little bit to much MeAm got into the solution. The base mdma that was produced was destilled and then crystallized. The final product had a faint smell of MeAm and tasted different. When tested it became clear that there was meam in it. 2 questions: How can the MeAm still be in it after destillation? Does it form an azeotrope when far to much is used? And how to remove the undesired MeAM? :P

hypo

  • Guest
MeNH2 doesn't survive A/B
« Reply #1 on: August 21, 2003, 10:38:00 PM »
A/B is obligatory.

(and it can't survive vacuum distillation either with it's low bp.)


Rhodium

  • Guest
Recrystallization of MDMA.HCl for Purity
« Reply #2 on: August 21, 2003, 11:03:00 PM »
The final product had a faint smell of MeAm and tasted different. When tested it became clear that there was meam in it.

Tested how?

Smell and taste is not an adequate analysis method to differentiate between different amines, as most aliphatic amines have a very similar smell. If you vacuum distilled the MDMA, the MeNH2 would evaporate. Also, it would have formed MeNH2.HCl when you crystallized the MDMA.

I believe that you simply did not recrystallize your MDMA.HCl properly, and what you smell/taste are either residual MDMA freebase, alternatively unknown byproducts carried over through the distillation.

Anyhow, whatever the identity of the amine-smelling impurity, it will be removed by recrystallization of your MDMA.HCl. Preferably recrystallize from 7 mL/g boiling acetonitrile, but you can also dissolve the salt in a minimum of boiling isopropanol, and then with good stirring add just enough acetone (or preferably diethyl ether) to form a lasting turbidity* in the solution. Stop the stirring, and allow the MDMA.HCl to crystallize at room temp for ~30 minutes, then filter, and wash the crystals with a little acetone (or ether), then place the filtrate in the freezer a couple of hours to recover a second crop (less pure) of MDMA.HCl, but this will amount to much less than the first crop. As this second crop is of lesser purity, you should ideally subject it to another recrystallization, and you definitely should if it visually looks worse than the first crop.

Note to everyone: This is a perfect example of why it is preferable to both distill your MDMA freebase, as well as recrystallize the MDMA.HCl afterwards to achieve a high purity of your final product. The A/B extraction before the distillation is even more important, but you hopefully already knew that, didn't you? ;)

Factoid: Recrystallizing (already purified) MDMA·HCl from boiling THF (~130mL/g) gives an insanely low density microcrystalline powder (unusable as purification method, but for you who want to choose your crystal size...)

*

turbidity

(http://dictionary.reference.com/search?q=turbidity)

zig

  • Guest
Thanks for your replies.
« Reply #3 on: September 04, 2003, 11:51:00 PM »
Thanks for your replies. It was tested with chromatografy. But if recrystallisation is necessairy for removing MeAm Hcl from the mdma hcl then it must have come over during the vac dest. It was also very hard for us to believe that meam could survive vac dest. But when far too much is used it forms some sort of azeotrope apparently. But recrystallisation is the key to purity.