Author Topic: Methylamine - Where'd my CO2 go?  (Read 2099 times)

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FriendlyFinger

  • Guest
Methylamine - Where'd my CO2 go?
« on: January 04, 2003, 04:39:00 AM »
Swim was making MeNH2 with Formalin/NH4Cl At 65°C and vacuum Approx 20". CO2 was comming nicely and had very slight reflux, then after 15 minutes, solution turns clear and tiny lovely CO2 gone. Second frigging time.

This was Swims second run with the same thing happening. First run yielded about 2g! Swims Formalin was about 2 years old and on the second synth I noticed polymerised powder on the bottom of the bottle, which was mixed for inclusion in the second synth.

So does Formalin decay over time? Swim should be seeing CO2 for hours. Can't recall reading any post about CO2 disappearing. I know the differance between CO2 and boiling bubbles. It's the Formalin man. What else could it be?

Regards,
FF.
2

SPISSHAK

  • Guest
Hmmm
« Reply #1 on: January 04, 2003, 04:42:00 AM »
You won't get Methamine production at  65 degress, that'ss where your CO2 went.
periodic application of vacum will remove CO2, but other than that that vacum reflux idea is a bunch of bullshit.

FriendlyFinger

  • Guest
Are you suggesting It's Bullshit specifically...
« Reply #2 on: January 04, 2003, 05:00:00 AM »
Are you suggesting It's Bullshit specifically for the HCHO/NH4Cl method or the hex/HCl as well, alla "Sumerian". I've read so much conflicting stuff.

Regards,
FF

sponsan

  • Guest
on the second synth I noticed polymerised...
« Reply #3 on: January 04, 2003, 05:18:00 AM »


on the second synth I noticed polymerised powder on the bottom of the bottle, which was mixed for inclusion in the second synth.



If you don't shake your 2 year old bottle of formalin like crazy before measuring it out, you'll find that you are just measuring out methanol.  Your formalin solution after shaking the bottle should be milky white.

terbium

  • Guest
Vacuum method is BS.
« Reply #4 on: January 04, 2003, 08:16:00 AM »
Are you suggesting It's Bullshit specifically for the HCHO/NH4Cl method or the hex/HCl as well, alla "Sumerian".
Yes, IMHO, the method that uses vacuum and temperatures below 104°C is pure bullshit. Also, there is no CO2 production during the reaction. As I have said many times the reaction conditions should be those specified in Vogel or Organic Syntheses.


Chromic

  • Guest
minor details
« Reply #5 on: January 04, 2003, 08:39:00 AM »
>Also, there is no CO2 production during the reaction.

I'd love to take a picture of the gases slowly bubbling out from the vacuum adapter into a graduated cylinder just to show you that there is some sort of gas production from this reaction. I still don't think I'm doing it wrong--someone will figure it out, and resolve this minor quibble on the details on this reaction.

... I fully agree that the vacuum method is B.S.--run this reaction at atmospheric pressure and ever so slowly increase the temperature!

terbium

  • Guest
Temperature, temperature, temperature!
« Reply #6 on: January 04, 2003, 05:42:00 PM »
I'd love to take a picture of the gases slowly bubbling out from the vacuum adapter into a graduated cylinder just to show you that there is some sort of gas production from this reaction. I still don't think I'm doing it wrong--someone will figure it out, and resolve this minor quibble on the details on this reaction.
I thought we had resolved this. It is because you don't control the temperature at 104°C but keep increasing the temperature until well above this where you finally do get some production of either CO2 or CO.

When the reaction is run with paraformaldehyde at 104°C as measured by a thermometer that dips into the reaction mixture there is almost no bubbling of the reaction mixture even though the reaction is indeed proceeding with alacrity.


raffike

  • Guest
Reaction should go like that: CH2O + NH4Cl...
« Reply #7 on: January 04, 2003, 05:57:00 PM »
Reaction should go like that:
CH2O + NH4Cl --> CH2(OH)NH3Cl --> CH2=NH2Cl + H2O
CH2=NH2Cl + CH2O + H2O --> CH3NH2*HCl + HCOOH