Author Topic: MeAm in MeOH from MeAm(aq)  (Read 1591 times)

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wacko_reaco

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MeAm in MeOH from MeAm(aq)
« on: March 14, 2002, 07:00:00 AM »
On Rhodium's site is this procedure by Sunlight
"This is a convenient way of making a 10% methanolic solution of methylamine freebase from the commercially available 40% aqueous solution.

Put in a 2-neck flask 700 grams of commercial dry NaOH, and using a compensating pressure separatory funnel attached to one of the necks, add slowly over one hour 350 cc of aq. methylamine to the NaOH. In the other neck attach a rubber stopper with a teflon tube and to it a glass tube with a gas diffusor ( a tiny glasfunnel with a glasfilter glued in it with 6 seconds glue or two component glue or just melt it tight with a torch ), and bubble the MA-gas in 1000 cc of methanol in a flask in a methanol- or water/ice bath. Reaction is endothermic, finally you can heat a bit the NaOH containing flask to force the liberation of the last gas, but it's not really necessary, just shake it to see a homogeneus paste. The compensation of pressure can be done using a regular separatory funel if you attach a 1-hole rubber stopper with a teflon tube connecting to the NaOH flask, if you use a 3-neck flask you can use the other neck, and if you use a two neck flask, you can use in one of the necks a 2-hole rubber stopper, 1 hole connecting to the stopper in the neck of the separatory funel and one to the ... dripping hole of it (excuse my english...)'

Just a thought, but using a concentrated MeAm.HCl solution instead of the aqueous MeAm solution would work just as well, would it not, provided more NaOH was used?
Any thoughts anybody, it would be good as one woud not have to dry the MeAm.HCl in the dessicator post production
Also can anyone swear by the MeAm Synth from hexamine in rhodiums site, i have tried the eluesis method with failure several times.
caio

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terbium

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Re: MeAm in MeOH from MeAm(aq)
« Reply #1 on: March 14, 2002, 07:13:00 AM »
Just a thought, but using a concentrated MeAm.HCl solution instead of the aqueous MeAm solution would work just as well, would it not, provided more NaOH was used?
Yes, a concentrated solution of MeAm.HCl will work well. Either way, you should be using a very large excess of NaOH.


Also can anyone swear by the MeAm Synth from hexamine in rhodiums site, i have tried the eluesis method with failure several times.
The Vogel synthesis that I have posted here I know works well (using ammonium chloride and paraformaldehyde). Hexamine instead of ammonium chloride and paraformaldehyde should work equally well under the conditions of the Vogel procedure.

wacko_reaco

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Re: MeAm in MeOH from MeAm(aq)
« Reply #2 on: March 14, 2002, 07:36:00 AM »
ta-that was pretty efficient replying, what 30min or so

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Sunlight

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Re: MeAm in MeOH from MeAm(aq)
« Reply #3 on: March 14, 2002, 11:56:00 PM »
Well, the procedure uses a very large excess of NaOH becuase I think it is very cheap and OTC for everybody. Commercial in this case means for house (drains...), not for laboratory. You'll finally throw away the NaOH, so spent and expose yourself the minimum you can.

wacko_reaco

  • Guest
meAm gas canister
« Reply #4 on: March 23, 2002, 08:23:00 AM »
that's an awesome idea madmax, did you know that madmax 4 is deep in post production

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