Acidic Hg/Al amalgam

[noj]

While doing a little experimenting, someone has noticed that if an aqueous acidic solution of HgCl2 is used in place of crystalline HgCl2, the reaction goes much nicer. Someone experienced no boiling up or what might be considered a runaway reaction. If someone else could give this a try to verify, I would bee glad to hear.
crucify the ego before it's far too late
and you will come to find that we are all one mind

[PrimoPyro]

noj, you know the routine, we need more details. What reaction? MD-P2P/MeAm? Or MDP2P/MeNO2?

Amount of water? Procedure? More details?

                                                    PrimoPyro
Vivent Longtemps la Ruche!

[foxy2]

What do you mean?
I think you need to explain what your talking about a little better.

Well it took me a while to post and PP beat me to it.
Thats what happens with multiple windows open.

NoJailForPot

(http://www.nojailforpot.com/)

[noj]

I really need a notebook  

Someone made some HgCl2 solution according to Zygoat, and kept this in the acidic solution without evaporating. This person finds it easier to handle fluids than powders.

Performing the amalgam, this person followed the MethylMan writeup. He then added @ 30mL of this dilute mercuric solution. No NaOH was added, to keep it acidic. Amalgamation was nearly complete, Al was grey and not too much shiny surface remained. Nitro/MDP2P/MeOH was dripped in at 1 drop a sec. Within 5-10 minutes, solution became hot, but never to the point of foaming. Reflux began @ 20 minutes later with gentle heating now applied. Addition complete 30 minutes.

Someone read that the addition of NaOH encourages the breakdown of Al. Since foil was used, he didn't want it to be encouraged. So acidic solution was used. Al completely dissolved within an hour. Continuing reflux for 3 hours.

These results are repeated by this person, but would like another testimony just to make sure it's reproducible.
crucify the ego before it's far too late
and you will come to find that we are all one mind

[amalgum]

Well I forgot where, but I once read somewhere that the Al/Hg reaction proceeds better under acidic conditions and basic conditions hinder the reaction.  I could be wrong though. Maybe your acid is reacting with the Aluminum hydroxides helping keep the pH down.

[foxy2]

Did it work?
And was the yeild good?

NoJailForPot

(http://www.nojailforpot.com/)

[PrimoPyro]

Highly interesting....

But wouldnt the acidic protons react with the methylamine, forming the methylammonium ion and an anion?

                                                     PrimoPyro
Vivent Longtemps la Ruche!

[noj]

Yeah it worked like the typical MM reduction. Yields were similar.

I like that nojailforpot.com    Needs to be expanded to any victimless non-violent non-destructive offense.
crucify the ego before it's far too late
and you will come to find that we are all one mind

[___]

amalgum, that is not a universal truth. Acidity in oxime and nitroethane redxns is neccesary (period). I've done this using GAA, HCl and silica gel. GAA being the highest yeilding. I'm not convinced that are reductive amination of ketones would benifit from acidic conditions. Otherwise we would just toss in MeAM.HCl, without freebasing it first.

[Osmium]

How much acid did those 30ml contain?
I bet the reaction was acidic for the first few minutes only, as soon as the Al started to react and some nitromethane was reduced to methylamine the whole reaction was basic just like any other Al/Hg amination.

[noj]

Os, that may be true. It was around 8% HCl (25% of 32% Muriatic) so perhaps it slowed the reaction in the beginning. Someone will test the pH throughout next time. It definitely seems to control the volcanic part of the reduction though.
crucify the ego before it's far too late
and you will come to find that we are all one mind

[PoohBear4Ever]

As long as one has the condensor power to contain it, is there such a thing as adding the nitro/ketone too fast(exothermia damper yields?)?

PB
"A taste of honey is worse than none at all"
~ Sublime

[blaztoff]

SWIM has found that almost running the amalgam as a pressurized rxn keeps the reaction mellow and improve yields. SWIM puts a straight vacuum adapter on top with the handy balloon and then fits a blowout valve on the nipple set for 12psi just under what the glassware will hold. The whole reaction is screwed clamped together using safe-loc setup. Its been safety coated and is nice and securlly wrapped. When the reaction gets running volcano style or if it starts to bubble up the condensor slow squeezing of the balloon to force some of the methlyamine back down the condensor that didnt condense seams to stop the eruption but keeps it bubbling like mad in the reaction flask. Havnt had one runnaway yet. And SWIM can preety much add the MeNO2/Ketone mix at a extremmly fast pace.
Hmm What would be the side rxns of running an amalgam in a pressure vessel be?  Hydrogen is released as a side product in this and is completly useless. Would keeping it in the reaction vessel cause bad or explosive side effects? The only gasses escaping here are hydrogen  and methlyamine? At least that would get past youre condensor. Or would the water formed from the amalgation become excess if it is a closed system and ruin the rxn. Or how about adding the methlyamine as a gas as the reaction progresses sort of like a hydrogenation.  SWIM has a Teflon coated vessel rated to 100psi that would probally be perfect for this.
Looking for that one pot-just add and let go-high yielding syth. For the lazy bees.  Damn looks like SWIMS going to be breaking out the hydrogenator again. Been itchy for some old fashioned hydrogenations again.

[baalchemist]

Hey NoJ, Baal knows exactly what you're talking about. Baal has some of that same solution you speak of, that he has been playing around with once again lately just like yourself. Baal has used it in the past a couple times in a pinch, but normally dried it to crystalline prior to use. Baal has found that a small 'scoop'(~100mg)(3-4 drops) of the granular white liquid is all it takes to kick out a normal Al/Hg/Nitro reaction. It doesnt make the reaction acidic, theres not enough acid in volume to do that. Its basically just wet HgCl2, if it does change the reaction Ph then youre adding quite a bit more than necessary. Baal can tell you from experience, this stuff can and will produce a volcanoe if given the chance. Baal took an accidental Al/Hg shower last week for 2-3 mins. or so, great for the complexion. Baal adds a small amount of MeOh to the white,HgCl2/H2O liquid to help dissolve some of the more chunkier stuff with it. Dispensing with an eyeroppper is a much simpler task I agree. Baal never posted anything on this because Baal figured someone would flip him some shit about being too lazy to dry his HgCl2. Glad to see that someone else enjoys it just the same.
GODISNOWHERE

[Osmium]

blatztoff:
why make this goddamn procedure any more complicated than it really is???
Is 90% yield not good enough for you or what?!? Sheesh!

[terbium]

Baal never posted anything on this because Baal figured someone would flip him some shit about being too lazy to dry his HgCl2. Glad to see that someone else enjoys it just the same.
Yeah, for the purposes here it is much better (safer) to not try to isolate the solid mercuric chloride but just keep it in the acidic solution and dispense it this way, in liquid form.

[baalchemist]

No doubt Terbium, the less hands on with that crap the better. It also kinda opens a door for the newbee that needs some HgCl2, but is still rusty in the synth area or has no other access to it. It is so easily made w/otc's and doesnt require much in labor, boilin', filterin' & a little mixing is about all.
GODISNOWHERE

[Moriarty]

I probably don't understand this process as well as I should and have had very little success with it, but as I understand it as the Schiff's Base.  I also read that this reaction requires acidic conditions.  Between 4-6 if I remember what I read correctly.  I can't quote that source right now (or at least not the author) but it was simply an Organic Experiments book my sister-in-law let me read.  My guess is that basic conditions only give the appearance of a sped reaction because of it's reaction with the Al, which I would like to remind everybody that it does without the presence of Ketone or MeNH2.  In the presence of H2 (this is just a guess) the solution starts to proceed to the lower ph on it's own.  Adding NaOH, I suspect, just slows down the reaction we want and creates a mess.  I used MeNH2 and probably screwed up there.  Again, I've had little sucess with this and would probably have done better if I would have listened and used Nitro.  In the words of Joe Dirt, "I'm new, I don't know what to do!"  In other words, this is my first post on the hive so take it easy on me if I'm wrong.

[sYnThOmAtIc]

I don't get the VOLCANIC part of this. Pinky has done many al/hg rxn's in beakers, flasks, rxn kettles and with minimal condensing paths (sometimes none) and even had drip rates as high as 8 drops per second and the reaction never bubbled out of the beaker or up and out of the condenser. So what is it that causes this happen? As the only thing that I can conclude to cause it is the heat put of from the addition mixture reacting with the foil at high rates causing the surrounding meoh to boil and as the heat has no where to go if the reaction is still paced as is then the meoh is forced out, causing "the bubbling over affect". So why hasn't this happened to pinky? As he would like very much to avoid this.

[Moriarty]

I've been using the methods set forth in brightstar's writeup.  In case your not familiar, there is no MeOH used and amalgam is done with water prior to dripping in MeNH2 and ketone (both in IPA solution).  As a matter of fact, they're not dripped in at all, they are simply added. 

Here's my point.  I've had it boil over.  That's only Al, HgCl2 and H2O.  Evidently this does not involve the reduction of alcohols (if it did we would all be using Al/Hg to reduce Ephedrine).  I that the lack of vigor is probably due to pour amalgamation (i.e. bad or insufficient amounts of Hg Salt).  When it has boiled over, I believe that their was an excess of Hg Salt.  The eppervescence is caused, I believe, by H2 produced during the process.  This is after all a reduction, which gives off H2.  I would be concerned more with lack of a reaction more than too much of one.  Next time I'm going to set up a reflux (which was not mentioned in the Brightstar writeup), make sure that I have a good amalgamation in progress and then start dripping in ketone/Nitro in MeOH so that I can nail down all these question I have about this procedure.  I certainly have not obtained good yeilds (sometime none at all) and look forward to seeing the fruits of my labor.  In the meantime, chemistry is still more fun than just about any other investment of my time and money.