Question regarding amphetamine synthesis via P2NP + NabH4/CuCL2

[KokosDreams]

Hey folks,

going through my notes (read below) I am wondering about three main questions right now:

1. Solution IPA/H2O 2:1 (10,4L) was added to the reactor and stir at room temp.
2. NaBH4 (500gr) was added at once while stirring.
3. P2NP (287gr) was added in small portions, so that the temperature of the mixture did not exceed 60 *С.
4. CuCl2 (30 g) in water (57,50 ml) was added at once the temperature of the mixture did not exceed 80 *С.
5. Thereafter, reaction was then held at 80 °C for 30 minutes using external heating.
6. The mixture is filtered with Buchner funnel to clean it from the solid waste of the CuCl2
7. 25% water solution of NaOH (2,3 liters) was added to reaction mixture stir 5 min and once stirring stopped leave separate phases 1 hour.
8. The aqueous phase was thereafter extracted with 2,3 liters of IPA.
9. The first layer separated is mixed with the IPA extraction and the mixture dried with anhydrous sodium sulfate, filtered with Buchner funnel.
10. IPA was evaporated on vacuum to an oil.
11. Water is added to the oil to make steam distillation.
12. The distilled mixture is extracted twice with DCM(around 250ml of DCM for each 2 liters of mixture)
13. Extraction is evaporated on vacuum in rotavap until gets off all the DCM.
14. 254gr of Amphetamine freebase are obtained(transparent oil with PH 13)

My questions now are:

1. What PH do I need to bring the reaction to before adding DCM?
2. Is it necessary to extract the aqueous phase with IPA or can I just extract with DCM and distill after adding NaOH at the end?
3. Is a 25% NaOH solution the best take or would another percentage of NaOH work better?
4. Instead of mixing the oil with water to prepare it for a steam distillation, can I fullfil a vacuum distillation in a rotavap too?

I was talking about the reaction with a friend and we got confused with these two steps

PS - This route was originally posted by @btcboss2022 and @William Dampier

Cincerly,

Koko

 

[Curiousonion]

Apparently IPA is not miscible with the salts so it will in fact separate.

 

[KokosDreams]

Apparently IPA is not miscible with the salts so it will in fact separate.

CuriousonionYeah, I got very confused by our prior conversation. Great that we could solve it

 

[KokosDreams]

Apparently IPA is not miscible with the salts so it will in fact separate.

CuriousonionDid you found some more info on the PH, is it 11 like we already assumed?

Question no. 4 is solved, vacuum distillation will work better as we discussed yesterday.

Regarding Q3, what's your take on that? I've texted with others that use a lower concentration while others just use 25%, I lack understanding of why that is.

 

[Curiousonion]

No idea about the pH. None of the rxn mention it. Need to keep looking for that

 

[KokosDreams]

No idea about the pH. None of the rxn mention it. Need to keep looking for that

CuriousonionGotcha!

 

[Curiousonion]

add cold saturated NaOH solution you made until you get to ~pH 11

 

[KokosDreams]

add cold saturated NaOH solution you made until you get to ~pH 11

CuriousonionPerfect! What temperature is best for the 'cold' NaOH solution?

 

[Curiousonion]

Perfect! What temperature is best for the 'cold' NaOH solution?

KokosDreamsJust keep the solution in the fridge

 

[KokosDreams]

Just keep the solution in the fridge

CuriousonionPerfect, thanks for everything