Nagai method ratios

[rotovap5002]

Does anyone one know the best ratios for the Nagai method?
On here people claim its 1:2:2 but more experienced cooks claim its 1:1:1.
Anyone who tried this can chime in?

 

[hacke8]

Methamphetamine From Ephedrine by Iodine and Red P

Starting reagents and materials 6 g Synthetic ephedrine hydrochloride racemate 1.8 g Red phosphorous (P) 12 g Iodine (I2) 100-150 ml H2O 3 g Sodium thiosulfate (Na2S2O3) 24 ml 25% NaOH 250-300 ml DCM 100 ml Petroleum ether HCl gas 100 g NH4Cl 25 ml H2SO4 83% Flasks 250 and 500 ml Beakers...

bbgate.com

Methamphetamine Synthesis from Ephedrine by Using I2 and H3PO2

Starting Reagents and Materials 6 g Synthetic ephedrine hydrochloride racemic 12 g I2 10.8 ml H3PO2 (50%) 20 ml H2O 50 ml 25% NaOH (15-20 г NaOH) 3 g sodium thiosulfate 250-300 ml DCM 30-50 g Na2SO4 100 ml Petroleum ether HCl gas 100 g NH4Cl 25 ml H2SO4 83% Flasks 250 and 500 ml Glasses Funnels...

bbgate.com

 

[rotovap5002]

Yes i read that, but people claim the ratios are wrong on those

 

[hacke8]

No, they are correct. I have completed the experiment with both methods.

 

[rotovap5002]

At what scale did you do the reaction?

 

[hacke8]

The maximum scale does not exceed 200 grams, otherwise the reaction is difficult to control. Unless you have a larger pressure reaction vessel.

 

[rotovap5002]

I know the red phosphorus one is but even the nagai route if you add the acid in intervals?

 

[Consider]

1:1:1 ratio is what I use, although it's violent be careful of explosion and poisonous gas release, phosphine gas