Problems recyling Al/Hg solvent

[lab_bitch]

After running a nitro Al/Hg, I basified, filtered, and stripped off the solvent.  I then tried using this solvent in the next reaction.  I first amalgamated the aluminum in some clean solvent, poured this solvent off, and added the recycled solvent.  When I began adding the nitromethane, the reaction seemed to slowly heat up to reflux temperature, and then the aluminum became covered by a black coating and stopped reacting.  Does anyone know what might have happened?

[Rhodium]

You didn't amalgamate long enough if that could happen. Your recycled solvent shouldn't contain anything besides methylamine, water and alcohol.

[Diggity]

Wouldn't you distill the solvent before basifying?
& I'm, somethin of a phenom, no need for da cron, I'm un-stopable.   
 

[Rhodium]

The aluminum sludge must be filtered off before the alcohol can be distilled. The addition of a smaller amount of aqueous sodium hydroxide followed by stirring the suspension for a few minutes often makes the sludge easier to filter (here is another example where Celite/diatomaceous earth makes a world of a difference when filtering something, likewise after an LAH reduction).

[lab_bitch]

Basifying the post rxn mixture is also essential to free the MeAm and MDMA adsorbed on the Al3+ surface.  I amalgamated the aluminum exactly as I did when I used fresh methanol as the solvent, except after amalgamation was complete, I pour of the fresh methanol and added the recycled methanol.  Could the fact that the recycled methanol had some water in it have something to do with it while the recycled methanol was pure Heet?  If so, how should I compensate for the water?  Use more HgCl2?

[ClearLight]

 Oh yeah... I just got a 25 lb bag at the local pool shop... cheap and wonderful!

Infinite Radiant Light - THKRA

[Rhodium]

I don't know how you amalgamate, but I think that the best way is to soak Al foil in 25 times its weight of 0.05% aqueous HgCl2 until hydrogen evolution becomes "moderate" (hard to describe this in absolute terms, but it is usually accompanied with the initially cold water heating to 25-30°C), then pour off the water (grey from suspended Al oxides), wash the foil with the same amount of water, then add the desired solvent (MeOH, IPA or THF, 10x the weight of the Al), followed by the reagents and then more of the same solvent (10x the weight of the Al). Finally aqueous NaOH or aqueous HCl is added if it  is desired to run the reaction under basic or acid conditions.

[scram]

You will know its amalgamated after you've stirred it for several minutes and let it sit unstirred for 30-45 seconds. Then gently knock the bottle and you will see bubble emminate as if you jarred a new glass of soda pop.

[Rhodium]

You should let it go further than that - it should bubble like a soda pop even without you knocking the flask...

[SPISSHAK]

Finally aqueous NaOH or aqueous HCl is added if it  is desired to run the reaction under basic or acid conditions.

Can you add HCL to this reaction and expect that the ALCl3 will keep everyithing under acidic conditions when the Al2O3, and Al(OH3) would seem to nuetralize this?

[Rhodium]

Yes, just like you can add NaOH to keep the reaction basic, even if the Al2O3 etc works as a buffer against it. Just look at Antibody2's acidic Al/Hg reduction of oximes for example.

[SPISSHAK]

Preacher who did some time in Levenworth who has since changed his ways, but he was describing some of the ways they'd cook meth from P2P and one of the things preacher man taught me was that they titurated the amalgum with H2SO4 before adding the reaction mixture.
So if this is the case then why wasn't everyone doing this to begin with to avoid that nasty argument we saw earlier between Lab_bitch and Protium over the mechanism of dehydration of carbinolamine to Imines.

Or does the aluminum oxides present work some kind of magic in this reaction that somehow converts the carbinolamine to the Imine without protonation so the alcohol can leave as water.
Maybe we should all stop arguing over mechanisms and just trust in magic to accomplish our goals.

[Rhodium]

"titurated"? Is that "titrated" or "triturated"? And in either case, what was the intention here?

[SPISSHAK]

I think It had something to do with a condesation of methylamine on P2P.
Any classic organic chem textbook will tell you that Imine formation is favored by lowered PH.
But if the aluminium oxides accomplish this for you then maybe it is'nt nessecary.
I read something about them having amphoteric properties as far as acidity and basicity goes.

[abacus]

Rhodium,

SWIMS procedure is to reduce nitromethane to methylamine using al/hg, add some NaOH and then simply distill the methylamine/methanol to recover virtually all of it.  Normally enough to animate over 200g ketone in a 2L flask.

Experiments that invloved filtering the sludge instead of distillation, yielded about half of what was expected.   

Please explain why the alcohol should be filtered first

Abacus
The problem is what you don't know you don't know.

[Rhodium]

When you are working with the volatile methylamine, vacuum filtering the solution will naturally suck a lot of the methylamine into the aspirator and down the drain. That won't happen when working with MDMA.

Heating MDMA freebase together with the Al sludge to distill off the solvent will definitely produce more bumping than necessary, cause unwanted side reactions and also cover your distillation flask with a thin layer of Al oxides, necessitating soaking the flask in strong acid or base to make it look like new again. And you need to filter the sludge off anyway after the concentration, so why not do it before?

[abacus]

sorry, i misunderstood.

I meant to say, SWIM makes methylamine via al/hg and then distills the methylamine/methanol to recover.  Then this is used seperately in another al/hg with ketone.

Experiments indicated distilling the methanol with the methylamine "dissolved" in it, was better than trying to vacuum filter the methanol, as you just mentioned.

I didn't mean to imply freebase is distilled with sludge.

Post al/hg with ketone and methylamine, the solvent is filtered (because that has the freebase) then stripped off to leave the freebase.  A/B washed and vacuum distilled.

The recovered methanol is then recycled.
 
Sorry about the confusion I caused. 

The problem is what you don't know you don't know.

[wyndowlicker]

Post Rxn mixture after 4 hours of stirring.the extra hour makes a difference as far as I can tell.I usually basify let cool.Usually it doesnt need to much time if you get your NaOH solution nice and cold in freezer.Begin toluene extractions.As of lately Ive noticed a bit of undisolved aluminum in the mix. been able to work around it and I chill all the Toluene extractions and immobalize anything possible.Decant and begin washes.Gravity filtration before basification had come to mind,but Filtering is very slow if not impossible.Would vac filtration bee the key?final product is beautiful.Just this minor problem?Anybees have any ideas?The gray sludge filteres very clear is this OK?
You can tell the queen of diamonds,by the way that she shines.-GD