Methamphetamine synthesis from P2P by NaBH4 reduction. Medium-Scale.

[btcboss2022]

Hello,

After many tests using Methylamine HCL based on this method I will share the best way that I found to obtain Methamphetamine freebase in big scale:

• 966 gr P2P​
• 14 liters Methanol
• 1183 gr Methylamine HCL​
• 638gr NaOH​
• 452 gr Anhydrous Sodium Sulfate​
• 105 gr NaBH4​
• 35 L distilled water​
• 7 Liters DCM​

- Fill the reactor with the 14 L of Methanol
- With stirring dissolve the Methylamine HCL
- Put the reactor temp at 0C(not the mixture temp) and add the NaOH, the temp will increase
- Once the temp come back to 20C add the P2P, the temp will increase stir it during 45min-1 hour
- Add 252gr of anhydrous sodium sulfate
- When the mixture temp arrives to 8C start adding portionwise the NaBH4 not exceeding the 20C
- Once all the NaBH4 has been added let it mixing under 20C during aprox 2 hours until the mixture stops bubbling
- Add the water and continue mixing during 5 min
- Add the DCM and mix it during 10 min
- Stop stirring and let layers get separated
- Keep the bottom layer and discard the upper one( not profitable to extract this aqueous phase)
- Add 200gr of anhydrous sodium sulfate to the saved layer and mix it
- Filter it in Buchner Funnel
- Evaporate the DCM
- Clean and smelly Methamphetamine freebase obtained

;-)

 

[K-Cyanide]

First, congrats on your successful aqueous reductive amination using NaBH4. Your reported yield of 88% is remarkable, as it comes close to the yields of the anhydrous path. Here yields are possible where the weight of the resulting freebase exceeds the input weight of P2P. (> 90,1% mol/mol).
Let me ask a few questions:

I) is the huge amount solvent you use (14 l Methanol) result of your experiments, if yes, to what extends where yields hurt by using less solvent?​

II) After extracting the base, and separating the organic layer you add 200g Na2SO4 to eliminate the water. 200g seems to me an overkill. Separating the layers in a separatory funnel is quite efficient, so why this large amount of drying agent?​

Thank you!​

​

 

[UWe9o12jkied91d]

A separatory funnel will not take out the water arrested by the organic layer aka emulsion.

 

[K-Cyanide]

I did not claim it either. What is the source of the water, exactly the aqueous formation of methylamine base and the formation of the imine respectively. Thatś it. For your called "arrested" water you will never need such a high amount. And finally, trying to extract a product/base out of an emulsion is not a good idea anyway.

 

[btcboss2022]

"And finally, trying to extract a product/base out of an emulsion is not a good idea anyway"
What you mean with that?Why not?

 

[K-Cyanide]

I was probably misleading. I meant you ŕe stuck, when an emulsion occurs. I usually had these troubles when extracting a compound from an aqueous solution with DCM/Ethyl acetate and the compound has similar or lower density than water. Anyway, back to my initial question:
I did a small test batch to prepare P2P from BMK Glycididate (sodium salt). The combined organic extracts had a volume of appr. 300 ml. To eliminate the water 5,8g MgSO4 was needed. Compared to your volume this equals to 135g.
Anyway, you do not even extract the aqueous phase, (i guess thats why 7l for expected 950g freebase), still you use so much drying agent. Of course, its your way to do it, but I do not understand it. Every g drying agent hurts the yield to a small extend.

 

[btcboss2022]

I don't extract the aqueous phase? Of course I do but with the organic layer at the same time, about the drying agent I use the necessary amount to dry the remaining water.
I'm not agree with that drying agents hurts the yield, some oil could be remaining in the drying agent(you will see it in the color of drying powder) when this happens you could wash the agent with solvent and evaporate this solvent.
Some people thinks that hurts the yield because they have more product before using it this overproduction is just water.
Thanks.

 

[rothschild33]

wanted to clarify with some previous message, this method works with MDP2P -> MDMA with just replacing the P2P with MDP2P?

 

[btcboss2022]

Yes but with the correct molar ratio.

 

[rothschild33]

would Ethyl Acetate be a viable alternative to DCM?

 

[G.Patton]

1340 g of meth free base from 1932g p2p is 62.4%. Anyway, congratulations!

 

[Stretcher5335]

69.35

 

[G.Patton]

You are not right. Count it carefully.

 

[Hank Schrader]

Chemically speaking, methamphetamine is methamphetamine. No matter what method it is obtained, borohydride or hydrogenation, etc...
But to be honest, NaBH4 methamphetamine is very inferior in terms of time of action and quality.
Perhaps minimal impurities that remain in other production methods and give a specific effect to the product.
In the case of borohydride, the action time is up to 16-18 hours and large dosages of the racemic product.
I think the people who synthesized borohydride methamphetamine would agree with me.
For example, methamphetamine obtained by the leukart method and divided into isomers is effective for almost 2 days.
Received methamphetamine through Sodium borohydride and separated into isomers acts only 16 hours and higher dosage.
The absence of impurities in the base is guaranteed by fractional distillation and division into isomers.
Of course, this sounds very strange, because from a chemical point of view, methamphetamine is methamphetamine, but as practice shows, this is not so.
Using the example of Viagra, I can tell you that fizer is unique in the production of sildenefil, and if you compare it with generics that have a similar amount of active ingredient, you will feel the difference.

 

[mithyl2]

Why is NaBH4 methamphetamine inferior? and is there a way to make it as high quality as other routes of synthesis?

 

[Smahk]

10% Methylamine in Methanol (w/w) - 1000 ml with 100 g MeNH2 (~3 moles

to make this from methylamine hcl, I was instructed with this procedure ? Is it correct? Thanks!

add equivalent of NaOH and methylamine hcl
Extract with dcm
Remove dcm
Dissolve in h20 by ratio

 

[G.Patton]

MeNH2 is gas at normal conditions

 

[Davidrobinson]

By the sounds of it you will probably end up dead messing with this stuff. You know nothing about it

 

[mithyl2]

is there a cheaper alternative to a Rotavap that i can use?

 

[Sciencenutz]

So if I was doing a bigger run of say 25kg P2P that would create 2mol of water per 138g p2p? So I would need to absorb 6521ml of water off 25kg? That seems like a lot of water can someone confirm this?

 

[curiousgeorge]

This is literally so interesting.

 

[mithyl2]

i'm still looking into this, but need some advice from here.

am i right in thinking that it won't be ok to perform this synthesis if i don't have a fume hood? (because of the methylamine being exposed to the air in my bathroom with me wearing a respirator and the window open and that's pretty much it.)

 

[G.Patton]

You can carry it out on a well ventilated work place.

 

[mithyl2]

what can be used in place of Dichloromethane?

 

[Sciencenutz]

Toluene will be ok but it will be on the top layer then

 

[mithyl2]

do you think there would any adjustments to quantity I would need when using toluene?

 

[Sciencenutz]

Quantity as in volume needed to extract it all? I would just use same quantity as DCM and just keep extracting untill your toluene has no color therefore you extracted all the oil