The method for Crystal Meth:
* 1 mol P2P = 134 gram, 1 mol (S)-(-)-alpha-methylbenzylamine = 121 gram (CAS Number: 2627-86-3, better known as 1-phenylethylamine btw.).
Say, per 100 g P2P 90 g of the phenylethylamine are needed.
Whats going on? It is a reductive Amination (or Alkylation to be more precise) but instead of Methylamine a chiral Amine is used which forces the formed molecule into the dextro orientation. So Amine and Ketone condense, splitting off water and the formed Imine is reduced to the Amine.
The Amine formed has some stuff attached which we do not want, and thats a Benzyl, Toluene basically. De-Benzylation is whats needed, and thats the heavy lifting the Pd/C has to do here. Splitting off the Benzyl-thing gives some Toluene and the oh so much desired d-Meth.
This must be tried on a not more then 10 g scale (P2P) first until it works, too many variables in play, same for catalyst re-usability: Theoretically yes, up to five times, but do not blame me if not.
80% or better yield. Improvements are possible, of course this is a working easy method though.
Improvement one: Do a CTH hydrogenation replacing most of the Hydrogen with an in-situ hydrogen donor like formic acid, formic acid salts, Limonene, Tetraline or mixtures thereof. Reaction must still be purged with hydrogen at the beginning, pump hydrogen through. pre-reduce the catalyst and attach an balloon filled with hydrogen. No pressure needed. Modern catalysts are more active, the 10% can be replaced by 5% Pd/C, the amount reduced to 15% of the P2P weight.Probably less, but thats still on the safe side. 2 mol of formic acid or its salts are needed per mol of P2P - simple, make the formate salt of the phenylethylamine and you have one mol covered, then add half a mol Limonene or a third or less of Tetraline (they donate more then one hydrogen) and its ok. Even NaBH4 can be used as hydrogen donor, donating four Hydrogens per mol. Running the reaction at about ph 4 protects the catalyst and speeds things considerably up. Hydrogenations are exothermic! You won't notice with small runs but it quickly gets interesting on bigger batches.
After the reaction let it sit under a blanket of hydrogen with mild shaking overnight - 5 to 10% better yields.
And this is a heterogeneous reaction to get the catalyst in contact the whole thing must be shaken. Not like mad but in a way that the catalyst is in even suspension and not near the bottom only. Stirring works but it atomizes the catalyst and it cannot be recovered by Celite filtration and the meth base must be vacuum distilled as the catalyst is not to remove by other ways. A PITA. Do not stir, shaking is easy. Look for "hydrogenation duck" on Google. Really. No joke.
I checked and CAS Number: 2627-86-3 is available no issues, costs about the same as BMK, so the costs are fine IMHO, real Crystal Meth is so rare nowadays that selling it as anything but a high-price, high quality, low supply item would be stupid. Nobody wants real Crystal for cheap back on the streets, the madness!, the trouble! but push it for 200 €+ per g to the poofters and your children won't go hungry any time soon.
