Maybe this will help you further I have not tested it personally yet. I could look in my folders maybe I can find the original PDF still
General Procedure for the Racemization Experiments. A
0.06 M solution of amine (100 mg) and thiol (1.2 or 0.2 equiv)
in benzene was refluxed for 2 h (stoichiometric condition) or 7
h (catalytic condition) in the presence of AIBN (an overall
quantity of 20 mol % of AIBN was divided into three equal
portions (when reaction time > 2 h) that were added successively each 2 h). After concentration, the residue was diluted
with HCl (1 M), and the solution was washed with Et2O. The
aqueous phase was basified with saturated sodium carbonate
and extracted with Et2O. The pure amine was isolated after
drying on MgSO4 and concentration
General Procedure for the Racemization Experiments. A
0.06 M solution of amine (100 mg) and thiol (1.2 or 0.2 equiv)
in benzene was refluxed for 2 h (stoichiometric condition) or 7
h (catalytic condition) in the presence of AIBN (an overall
quantity of 20 mol % of AIBN was divided into three equal
portions (when reaction time > 2 h) that were added successively each 2 h). After concentration, the residue was diluted
with HCl (1 M), and the solution was washed with Et2O. The
aqueous phase was basified with saturated sodium carbonate
and extracted with Et2O. The pure amine was isolated after
drying on MgSO4 and concentration
- By Sciencenutz
I have access to aibn and thiol but would appreciate some help with the proper ratios converted to say per kg of L-meth freebase? I'll post my results
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- By HerrHaber
the procedure stated above is on an analytical scale and you must first understand clearly all that is said (for example a 0,06M soln of amine in benzene from 1kg would be really on an industrial scale and benzene is notoriously carcinogenic even if it smells nice) you need to have mastered the intermolar conversion calculus and understand fully what 20% molar eqivalents are... chemists usually write like this because it is more relevant to them than having a cheesecake recipe type of writeup
- By HerrHaber
Please excuse me if my comment was a bit sour... it's the stigma of introducing phosgene on the battle fields that make's me somewhat arrogant in appearance, but I am not really that much of a bad person just maybe harsh on chemical knowledge (and most notably on myself). Calculating instead of you will not be educative of me but if you give it a try I promise to proofread it and kindly guide you.
- By Sciencenutz
Well here are the weights of all 3.
L methamphetime 149.23g/mol
Methyl thiogylcolate 106.14g/mol
AIBN 164.21g/mol
Therefore would it be 1 mol L-meth and it says 0.2 equal so 106.14x0.2=21.22g. And a 20% for aibn is 32.84g.
So say I did 149.23g L-meth and 21.22g thiol and refluxed for 7 hours while every 2 hours add 10.94g (32.84/3=10.94g) of AIBN.
Would that be the correct numbers?
L methamphetime 149.23g/mol
Methyl thiogylcolate 106.14g/mol
AIBN 164.21g/mol
Therefore would it be 1 mol L-meth and it says 0.2 equal so 106.14x0.2=21.22g. And a 20% for aibn is 32.84g.
So say I did 149.23g L-meth and 21.22g thiol and refluxed for 7 hours while every 2 hours add 10.94g (32.84/3=10.94g) of AIBN.
Would that be the correct numbers?
- By HerrHaber
This seems correct, sorry for judging you harshly again, don't forget about the amine concentration in the soilvent which is said to be 0,06M benzene (this concentration is much to low on the preparative scale and substitute for benzene like toluene is strongly advised unless there is a boiling boint rellevance, benzene boils at arround 68C approx and toluene is 110C)
- By HerrHaber
Correction: boiling point is relevant since you need to reflux so just be careful of the vapours inhaled since it is an achetypal carcinogen even if not a very potent one it can induce severe liver damage upon chronic exposure. Also the boiling point of benzene I mentioned is from memory and you should check it out. I trust the molar masses were checked out by you so I did no documentation just made sure your thinking is that of a chemist.
- By btcboss2022
Thats correct I found this same process some time ago and the problem is only possible in that amounts higher ones wont works correctly so to much time for low amounts I didnt try It.
- By Sciencenutz
So would it be L meth HCl or could I use the freebase? And btcboss what do you mean by "higher ones won't work"? Also I do not like benzene either maybe a suitable substitute would be acetonitrile since bp of benzene is 80 and acetonitrile 82?
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- By btcboss2022
Should be from a L-Meth freebase solution with the tiol.
I mean that this process is not efficient in larger amounts.
I mean that this process is not efficient in larger amounts.
- By Sciencenutz
Is there any other ways that know of? From my reading I've done there's many articles saying that the mexican cartels do this at pretty massive scale...why would this not be suitable for large scale?
- By K-Cyanide
I am also keen to dig deeper into this topic. Even the EU authorities are writing in their publications of the massive use of this kind of "recycling" method for the otherwise disposed L-meth fraction. I will find one of the articles and will post it here.
One topic the underground chemist has always to deal with, when following academic/scientific papers, are the high ratios of solvent to compound.they are using. The 0.06M concentration of L-meth base is ridiculous low, for preparative or decent clandestine chemistry quite useless.
So actually we need to develop a practical method derived from existing information like this paper.
I am afraid calling the Mexican cartels for support is not an alternative route to gather knowledge. *smile*
I have some experience in "converting" and applying scientific papers to basement conditions, though not (yet) for meth.
One question: Which entry in Table5 in the paper to you determine for L-meth /0.2equiv. methyl-thio respectively?
One topic the underground chemist has always to deal with, when following academic/scientific papers, are the high ratios of solvent to compound.they are using. The 0.06M concentration of L-meth base is ridiculous low, for preparative or decent clandestine chemistry quite useless.
So actually we need to develop a practical method derived from existing information like this paper.
I am afraid calling the Mexican cartels for support is not an alternative route to gather knowledge. *smile*
I have some experience in "converting" and applying scientific papers to basement conditions, though not (yet) for meth.
One question: Which entry in Table5 in the paper to you determine for L-meth /0.2equiv. methyl-thio respectively?
- By Sciencenutz
Yes I would use just enough to comfortably dissolve the benzene as this would be on 25kg scale and wouldn't make sense...I have all chems accessible so any info you have would help as I can test this out pretty easily...do you have any ideas of a benzene replacement or must benzene be used
- By K-Cyanide
yes, this sounds reasonable, as a rule of thumb i would suggest a volume ratio of 1:6 to 1:10, in this case 1:10 would be 1000ml L-methamphetamine free base dissolved in 10.000ml benzene.
The choice of solvent is determined by various factors. To my knowledge these are the boiling point when using a reflux (HerrHaber stated it already) , the solubility of the solvent in water and vice versa when applying water sensitive procedures (i.e. Grignard Reactions), the said toxicity, the polarity etc.
So what would i choose here: I guess also Toluene should work, as well as Xylene, What about Ethyl acetate? Did you consider it already ?
The choice of solvent is determined by various factors. To my knowledge these are the boiling point when using a reflux (HerrHaber stated it already) , the solubility of the solvent in water and vice versa when applying water sensitive procedures (i.e. Grignard Reactions), the said toxicity, the polarity etc.
So what would i choose here: I guess also Toluene should work, as well as Xylene, What about Ethyl acetate? Did you consider it already ?
- By btcboss2022
As far as I know (I am not officially a chemist) AIBN is a radical initiator and thiol (in this case methylthiogilcolate) reacts with AIBN creating another radical, so as radicals they have a short life in the presence of oxygen or water, for this reason I think it would be difficult to maintain an efficient process on a large scale without an inert atmosphere.
In an inert atmosphere it might be possible.
Without conditions of inert atmosphere I would try it (in fact when I have free time I hope to do it) in stoichiometric condition (reflux 2 hours) with these quantities:
0.06 M of free base solution in toluene
Methylthiocylcholate 1.3 equiv
30 mol % AIBN
The reason is that less time reacts less chance of product loss due to radicals in the presence of oxygen for this reason I would add a little more thiol and AIBN than the original process.
THIS IS WHAT I WOULD TEST DON'T MEANS IT'S AN OFFICIAL METHOD OR SIMILAR AND I COULD BE WRONG.
In an inert atmosphere it might be possible.
Without conditions of inert atmosphere I would try it (in fact when I have free time I hope to do it) in stoichiometric condition (reflux 2 hours) with these quantities:
0.06 M of free base solution in toluene
Methylthiocylcholate 1.3 equiv
30 mol % AIBN
The reason is that less time reacts less chance of product loss due to radicals in the presence of oxygen for this reason I would add a little more thiol and AIBN than the original process.
THIS IS WHAT I WOULD TEST DON'T MEANS IT'S AN OFFICIAL METHOD OR SIMILAR AND I COULD BE WRONG.
- By btcboss2022
I forgot to comment about the other ways that you asked:
Another way possible with Raney Nickel as catalyst in pressure conditions. (I never tried just literature)
Anyway I don't like talking so much about processes that I don't test it myself but this one is enough interesting to participate even my low profile in chemistry.
This doc could help with the process of the thread.
Another way possible with Raney Nickel as catalyst in pressure conditions. (I never tried just literature)
Anyway I don't like talking so much about processes that I don't test it myself but this one is enough interesting to participate even my low profile in chemistry.
This doc could help with the process of the thread.
https://pubs.acs.org/doi/full/10.1021/jo061033l
- By Sciencenutz
So you would reflux the toluene and not just bring it to 80c? And what is 0.06M convert to in grams of freebase I'm a bit confused with that part
- By btcboss2022
Another possible way could be by epimerization in that case with HCL in toluene.
This doc could help:
https://doi.org/10.1002/jhet.5570180538
This doc could help:
https://doi.org/10.1002/jhet.5570180538