NaBh4 meth Problems

[Acab1312]

Hello, I have recently had a problem with the NaBh4 to meth problems.
1.I dissolve the methylamine hcl in methanol
2. Cool and add the naho, and let it stir for 10min
3. Add a dry agent molecular sieve 3a or silica gel
4.now I add the p2p and let it stir for 1 hour under 15°
5. I add the NaBh4 (temperature always below 15°).
6 when everything is added, I let it stir for 2 hours.
7. Now I add h2o, let it stir for 5 min
8. Then toluene and leave it for 15minStir.
9.I have the layers separated.
10. Separate the toluene, which is now yellow.
11. Add h2o and set ph to 4.
12. Separate the aqueous layer and freebase it again to separate isomers. The response would be made successful several times. Unfortunately, I had to change my supplier and since then it hasn't worked anymore. Either ph 4 has a white substance (which is presumably naCI). And zero yield. The only change is my supplier of chemical. Or have I made a gross mistake in her place, for I do not see myself?

 

[craris100]

1.I dissolve the methylamine hcl in methanol

Thats the problem.

How to properly generate Methylamine gas to Methanol

I have problem because I don't know how to properly generate Methylamine gas I putted 100 grams of Methylamine in 80g of water and mixed in one beaker Then I putted 200 grams of NaOH in erlenmeyer flask which was connected with silicone tubing to ice cold liebig condenser and then to Jar that...

bbgate.com

 

[btcboss2022]

Why is that a problem exactly?
I see more problem to wash the mixture with toluene at PH4 I always use and recommend PH2 for that stage and no leave it stirring at least 4-12 hours after NaBH4 addition.

 

[Acab1312]

OK, if I understand correctly, I'm supposed to set it to ph2.

And let the reduction be reduced by 4-12 hours?

I'll definitely try it out

Thank you very much

 

[btcboss2022]

No no, are different stages sorry for the misunderstanding.
The PH2(acid washing) must be after NaBH4 reduction.

 

[Acab1312]

OK perfect, now I understand that thank you very much I will try it like this. The main thing is that it works again.

 

[Acab1312]

Thank you very much. I'll try that next time, I'm just a bit surprised. Since I did it without any problems before. To produce the methylamine freebase in situ. Do you happen to know what this white precipitation is, which appears at the end of the ph setting?

 

[craris100]

Probably nacl and other salts

 

[Acab1312]

OK thank you

 

[Throw-off]

What did ol' LaBToP use to say "Time is NOT Money!" Let it mix in total for 8.5hrs..

Also why are you gassing it down to Ph 4? I'm presuming your cliental doesn't have taste buds at Ph 4 the gear would taste putrid!

I'd love to watch someone try and dissolve methylamine HCI in acidic conditions.. You wouldn't have a left handed screwdriver by chance?

 

[Acab1312]

OK thanks for the advice for the reduction time I will implement next time.

Because I set ph to 4 to get all the product. Then the ph 11 is restored. Then add ph11 again, then hydrochloric acid without h20 on ph5. The freebase hydrochloric acid mixture is heated and crashed into ice-cold acetone. Place in freezer 24h, separating the solid from acetone. Then recrystallization. Thanks for the advice, but the customers have never criticized each other for taste.