Author Topic: MeAm a la Rafike, How bad are the fumes?  (Read 1200 times)

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NeoSynthesis

  • Guest
MeAm a la Rafike, How bad are the fumes?
« on: October 10, 2003, 10:01:00 PM »
SWIM's about to dream up some MeAm by way of NH4Cl + Formalin. Wondering how bad the fumes would be on a run of say... 137g/Ammonium + 250ml of Formalin. Any insights? SWIM's a city bee with minimal ventilation & curious to see how this reaction would progress. But better safe then sorry - So... experienced bees out there, HOW BAD's THE SMELL? Is this doable? Help!


OcoteaCymbarum

  • Guest
There is a fish smell
« Reply #1 on: October 11, 2003, 03:19:00 AM »
but no smell whily preparing it. To make sure, just plug a hose of some sort on the vaccum adapter that leads outside.
I've always done it distilling style, not the way Raffike does it so most fall in the receiving flask. It will smell like fish after, work as fast as possible behind closed doors and wash your clothes after.

DRIVEN

  • Guest
Techniques to minimize l'odour de poissant
« Reply #2 on: October 11, 2003, 04:47:00 AM »
In addition to OC's comments, A lot of fish smell is created when the hot MeAm concentrate is poured out into a dish. It seems that one has to get it out of the flask before it cools or else it will harden in the flask. An alternative is to let it cool in the flask, add in a suitable solvent (n-butanol, there must be better one though) and reflux to dissolve the MeAm. Pour off the saturated solution and allow the MeAm to crystalize out of the solvent as it cools. Get it really cold, vac filter and get it into a container.

DRIVEN :)


NeoSynthesis

  • Guest
MeAm into a solvent
« Reply #3 on: October 11, 2003, 10:27:00 PM »
Thanks - Any clues on what a good solvent for MeAm xtals would be?

Peace -
Neo

DRIVEN

  • Guest
MeAm HCl solvent
« Reply #4 on: October 12, 2003, 12:08:00 AM »
Absolute alcohol will work. See following post for its use:

Post 455381

(technology: "In order to obtain a pure product, the crude...", Newbee Forum)


DRIVEN


NeoSynthesis

  • Guest
Absolute Alcohol?
« Reply #5 on: October 12, 2003, 12:53:00 AM »
You mean like rubbing alcohol sold in pharmacies?

yinga

  • Guest
Absolute alcohol is 95% ethanol, not rubbing...
« Reply #6 on: October 12, 2003, 02:42:00 AM »
Absolute alcohol is 95% ethanol, not rubbing alcohol (isopropyl).  N-butyl alcohol is the best solvent for recrystallizing a MeAm.Hcl and nh4.hcl mixture because nh4.hcl's solubility in it is next to nothing.  Dry isopropyl alcohol can also good for small amounts but MeAm.HCl's solubility in it is so low that the volume needed becomes impractical for recrystallizing large amounts.  Ethanol is next best after propanol (can you see the trend developing here) but not as good as n-butyl in terms of nh4.hcl solubility.  I followed Chromic's suggestion and recrystallized in MeOH and had good results.  Supposedly the nh4.cl solubility in MeOH (which is already fairly low to begin with) becomes negligible when the MeOH is saturated with MeAm.Hcl.  Even assuming that isn't true, recrystallizing twice would still give >99% purity.

I learned all of this by UTFSE, and you could've too.  A search for "methylamine recrystallization solvent" returned the thread

Post 16333 (missing)

(edge: "Methylamine", Newbee Forum)
in the first page of results.  Making redundant posts might not seem like a big deal, but to those that have been here for a while responding to them is like feeding trolls.  They also increase the noise ratio of TFSE results.

abolt

  • Guest
Absolute alcohol is 95% ethanol, not rubbing...
« Reply #7 on: October 13, 2003, 05:45:00 AM »
Absolute alcohol is 95% ethanol, not rubbing alcohol (isopropyl).

Absolute alcohol is 100% Ethanol. 95% Ethanol is known as "Denatured alcohol" or "Methylated Spirits."


Flippie

  • Guest
95% Ethanol is known as "Denatured ...
« Reply #8 on: October 16, 2003, 09:48:00 PM »
95% Ethanol is known as "Denatured alcohol" or "Methylated Spirits."

I disagree, denatured ethanol just means that a denaturing agent [often methanol ranging from 0.1-5% ( or another toxic substance like cyclohexane, toluene, etc... ] has been added to the ethanol to make it undrinkable. The big price difference between food-grade ethanol and denatured ethanol is taxes. Since water and ethanol form an azeotrope around 95-96% you cannot simply further distill to get 100% pure ethanol. [I believe one commercial applied method is to add benzene to this azeotrope before further distilling to remove the remaining water but I don't know the details]  For crystallization and other applications where "no water" conditions are required you either use the 100% or you dry your 95% "absolute" ethanol using a drying agent.

All you need to know about drying agents can be found on

https://www.thevespiary.org/rhodium/Rhodium/chemistry/equipment/dryingagent.html



To conclude: I'm aware that some chemsuppliers reserve the term "absolute" for 99.7-100% ethanol but 95% does not necessarily mean denatured.


Chromic

  • Guest
Agreed
« Reply #9 on: October 18, 2003, 07:52:00 AM »
In the lab we use 95% EtOH from Fisher or Aldrich all the time... it is not denatured (one could drink the stuff and in the past people have been known to) and thus not called denatured alcohol.

zero_nrg

  • Guest
very little stink
« Reply #10 on: October 30, 2003, 06:25:00 PM »
Tried this a couple of times using the Vogel procedure.  Very little stink.  Used condenser in reflux mode after distillation setup produced little distillate.  Raffike proc. essentially the same.  I believe it was Osmium or wizard x who said not to worry about the amount of distillate and just heat for required amount of time.  Bring temp up slowly though.  A distinction has to be made between liberating the freebase and producing the HCL. -zero