Al Amalgamation using Methanol as Solvent

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Author	Topic: Al Amalgamation using Methanol as Solvent
MK Ultra unregistered	posted 01-12-99 08:34 PM Has anyone dreamed about Osmium's variation on the Al amalgamation using methanol as a solvent instead of ethanol or instead of isopropanol via Shulgin's variation. If not, is there a reason why methanol would not be a good substitute?
quirks Member	posted 01-12-99 09:03 PM Low bp for a rxn that tends to heat. No personal experince with it, but I think everyman succeded. So long as you have some good ice cooling handy, thick al, and a good condensor wouldn't hurt either.
Bright Star Member	posted 01-12-99 09:27 PM I think this is an excellent idea. This way you could heat to reflux, ~50-60C, chill with an ice-water condenser, and thermodynamic control is maintained.... right around the temperature that Ritter, Shulgin, and Elusis thought should be maintained. I'd use slightly more MeOH, because you'd loose a little throughout the experiment. And why not? Its easy to get rid of....
quirks Member	posted 01-12-99 10:57 PM If your going to use reflux to control the tempeture do it with a big flask. I wouldn't want to do it with a flask any more then 1/3 full. Or at least have ice handy.
Semtex Enigma Member	posted 01-13-99 05:23 AM Rhodium: I heard a little bird say that you once said that Ammonium Nitrate and water cool when mixed. So how long does this effect last? Would it be suitable for use as an ice bath?
sunlight Member	posted 01-13-99 07:09 AM Yes I think this is a very good idea. I thought about it time ago, but I never did it. May be in my next dream I can do it.
Ritter Member	posted 01-13-99 09:53 AM Methanol is by far the very best solvent for this rctn. I say this without hesitation because yields approaching 95% are routinely recognized. BS is right- MeOH is perfect because it boils at 60'C so it can't get so hot as to allow decomposition or rapid runaway as with IPA. Perfect yields are recognized using the following technique- and don't question Ritter on this as it is reproducible every time! 30g Aluminum which is about twice as thick as Reynolds Wrap Heavy Duty foil are cut up into 1" squares. A soln of 1.5g HgCl2 in 800ml MeOH is dumped onto aluminum. Heating is commenced by placing beaker on hotplate set to lowest setting. When amalgamation is sufficient (about 10min required) a mixture of 60g ketone ang 75ml 40% aq MeNH2 is dumped in. Simply keep this on the heat until Al is dissolved (about 4hrs) while periodically adding more MeOH to compensate for evaporation. The temp of the mess should be maintained at about 50'C for the duration. If it slows down too much ad a kicker of another .5g HgCl2. When all Al is dissolved dump into about 1.5l H2o containing 150g NaOH, extract w/ 1L toluene, wash toluene w/ water and sat. NaCl many times to remove Hg, dry toluene extract w/ MgSO4 and bubble w/ HCl until the first hint of a yellow or orange tinge appears. Cool toluene/crystal mess in freezer then filter to recover AT LEAST 60g product. These numbers are not bullshit and before anybody flames me, try this and amaze yourself first! Oh, yeh, only methanol is miscible w/ the NaOH quench, EtOH and IPA will all float on top causing problems w/ the toluene extraction. More Later, Ritter
Beagle Member	posted 01-13-99 11:04 AM I agree that methanol is absolutely the best alcohol to use in reductive amination. Never really thought about why that was, but temperature control sounds like a good explanation. Now, any idea why does Shulgin adds NaCl to the reaction when using aq. methylamine rather than the HCl salt?
boingo Member	posted 01-13-99 01:06 PM oh boingo is getting excited now! Ritter: You don't mention any sort of stirring. Am I correct in assuming that it is not necessary? Also, could one substitute MeAm-HCl here if they included an equimolar amount of NaOH? Oooh boy, combine this with Ritter's in situ MeAm production with nitromethane, and I think we have the most facile small-scale amalgamation setup! All bees with amalgamation woes should be very excited right now! peace, boingo
Bright Star Member	posted 01-13-99 03:17 PM Beagle- I've always wondered that same thing ... Perhaps its to complex the water, but only strong enough, untill its needed? Boingo - Stirring is very necessary. Without it, your ketone will go to the top, and the Al will be on the bottom. I wouldn't put in an equimolar amount of NaOH.. I'd put in an 0.75 molar amount (of NaOH vs. MeAm.HCl) ... assuming that you put in a 2.5 molar excess of MeAm.HCl anyway ... Ritter - Good to see ya. What do you think about Shulgin's washing of the Al foil with water before the adding of the ketone+MeAM solution? He basically washes away all of the Hg in solution... and thus minimizes the chance of Hg in your final product. It is my belief that the Hg is there only to destroy that outer layer of Al2O3 ... and once thats gone, the Hg has no other purpose. I have (hypathetically) made this work with great success without the Hg in the reaction flask. Your thoughts?
equarius Member	posted 01-13-99 07:01 PM Ritter, alls I can say is WOW. This is exactly what I've been searching and waiting for. It's simple and sounds like the perfect variation. A couple questions: Did you mean reflux with a condensor when you say heat, just wondering as every other variation uses reflux. Also I'm pretty sure that MeNH2HCl can be used instead of aquaous Methylamine, is that right. No decanting of amalgated catalyst ala Strike? Have you left out the little things (like decanting) or is it really a simple as you say? Also if you can contribute anything to the PdCl2 recycling question I posted in the Chemical section I would really appreciate it. Good work and wicked post.
Ritter Member	posted 01-13-99 11:00 PM No reflux if needed, this is best done in a beaker. Rctn temp doesn't need to be held at reflux temp, just high enough for Al to maintain degradation- about 45-55'C. This high a temp is only needed for the thicker Al foil I am talking about. Thinner foil will cause a runaway rctn. at this temp. At 50-55'C some evaporation of MeOH will occur. This is no problem, just add more MeOH periodically. Stirring: As Bright Star mentions this is essential at the beginning of the reduction to make sure all is homogenous. Once all is mixed thoroughly no stirring is needed. The ebolution (sp?) from the bubbles of H2 produced usually does a good enough job. Washing, filtering Al sludge: FORGET IT!!! in small batches such as this the entire grey reduction soup is dissolved in NaOH soln as mentioned in my first post. A VERY HIGH yield of product is then recognized when the entire mess is extracted w/ toluene as described. Filtering the Al salts really sucks because a lot of product is always lost. Please also note that only 30g Al is needed in my first post where Shulgin would use about 45. Shulgin uses a huge excess and I believe this can cause some degradation of product. 30g is a much more reasonable quantity of catalyst- and still an excess. I don't have much time for more info but if people follow my details in these posts and my many posts on this topic from the past (not to mention my entry in TS2) there should be no reason for anyone to report a "dismal" yield from Al/Hg ever again. Oh, yeh, don't skip out on those final washings of the toluene extract w/ water and NaCl. It's going to really piss me off if I hear about any shit contaminated w/ Hg showing up anywhere! Bright Star-- just realized you asked me some other things-- will respond tomorrow! Ritter
Belladonna Member	posted 01-14-99 12:29 AM Bright Star, is it true that the Hg is only used for baring the metal from the Al2O3, and the Al is used for reduction? I've got an idea of how not to use any Hg at all, assuming the above is correct: 1. Use thick foil, as Ritter says. This increases the mass of aluminum to aluminum that could be oxidized by the air. Possibly cleaned-off soda cans would work? As well as aluminum blocks, but slower. 2. Prepare a quantity of methanol to work with in three separate beakers. Two contain methanol only, while the third contains your choice of either conc. HCl, or conc. NaOH solution. 3. Place the foil in the reaction beaker (with base or acid), and wait a while after the evolution of hydrogen gas is at a constant rate (all oxide removed.) 4. Quickly removed the dripping metal and immediately place it in the second beaker, to rinse off the acid or base. 5. After the first rinse, rinse again with methanol from the third beaker. 6. You now have aluminum metal, oxide-free, ready to reductively aminate that ketone of yours. Note: This is pure fancy, of course. Actually, teaching undergraduates how to make alum salts, it was necessary to clean the metal with strong NaOH prior to use. Also, I assume that there is no reaction between methanol and aluminum, so prepared metal could be stored in a sealed container indefinitely. Although, a sonic dismembrator should be used to get rid of oxygen dissolved in the MeOH prior to use as a storing agent. And if one has the facilities to work with oxygen-free environments, this would be easier. Yeehaw! Bzzzzzzzzzzzzzzzzzz.......
Semtex Enigma Member	posted 01-14-99 03:30 AM Ritter: If I understand correctly, in Osmium's variation the purpose of the reflux condenser is to control or minimize the MeAm loss. Are you saying that this step is not nessesary?
sunlight Member	posted 01-14-99 04:09 AM In my dreams I do the things similar to Ritter, but with a few differences. First one is I us ethanol 96, next time I'll use the cheaper methanol, both are OTC here. I amalgamate a la Shulgin, so the most part of HgCl2 is out of rxn. I filter the sludge, it's horrible, may be the next time I'll try the Ritter method. I use the thickest aluminium I can, but anyway is too much thin, I mix ketone and methylamine with ethanol first and I prechill the alcohol, when the amalgam is prepared, I put the ketone mix and the alcohol, and when the temp start to be near 35 C I put the rxn in ice, and a refluxer. Temp climbs to boil, even in ice, and when boiling is finished I keep temp between 50-60 C. After filtering I evaporate all alcohol and water and I diolve teh oil in toluene, rinse the flask with toluene, neutralize till 5 with comercial 24 % HCl and boil with stiring till 110 - 115 C, only a brow oil remain, and when is at 60 C or so, I put anhydrous acetone, and cool. The crystals are easily cleaned with more acetone and in the filter with small quantities of acetone, like eluting in cromatography, it's the same. The final product is snow-withe crystals. My last dream was with 100 grams MDP2P, 100 cc of MeNH2 40%, 44 grams Al and 1 liter ethanol, and I got 99 grams plus the little I didn't remove in filter etc... Well yields depends mainly on teh purity of ketone of course, and this one was highly pure. BTW I was 5 hours filtering the cake and washing it twice with the same volume of methanol. We can make a puzzle with the good ideas, like avoid filtration. The method I use for crystallitation (it's not new) runs perfect for me.
Bright Star Member	posted 01-14-99 08:29 AM So... Are ya'll excited? I am! Equarius- If you use the 2.5molar excess of MeAm.HCl (vs. ketone) also add ~1.75molar excess of concentrated (20% or greater) NaOH solution. This will add the salts (NaCl) to the solution (that Shulgin does), and create the aq.MeAm. And it really is that simple. It is my opinion that those who have trouble with this method, are actually having trouble with the ketone formation. No ketone = no product. Be sure you have ketone! Bell - Hummm.... I'll have to think about that one.... It really sounds good ..... I'll get back to you..... Semtex - Thats why you should use a HUGE excess of the MeAm .... If you lose some ... It doesn't matter! Sunlight - Interesting stuff! No need for that Ethyl ether, eh? Thats great. Can you buy the 40% MeAm, or did you make it? By what method did you make the ketone? Great post! GREAT THREAD!
psychokitty Member	posted 01-14-99 09:59 AM I recently found a limited review in the red multivolume "Encyclopedia of Reagents for Organic Synthesis" describing the various uses of aluminum amalgam in organic chemistry. Under the heading "C=N Bond Reduction" there were citations of articles that might detail how aluminum amalgam reduces schiff bases to the corresponding amines. So I'm going to post the references here in hopes that maybe somebee, somewhere in the hive, will look up the journal articles for me, as I unfortunately have a limited library resource. My impression is that the articles might be reviews with loads and loads of information as to how the Al-Hg reaction can be optimized. Also, there were several diagrams of various applications of Al-Hg, and guess what? In practically all of them, THF was used as the solvent. This should not be so surprising as THF, like methanol, also has a bp somewhere in the 60degC range. So now we might finally resolve the mystery behind why Eleusis was busted with multi-liters of the stuff. I mean, hasn't anyone ever wondered why he had so much? I did and do. After all, I never really bought the idea that he was using that much THF for nitroalkene reductions. Another coincidence: The use of THF seems to be in line with some other references that I have posted in the past. In one was information taken from a US patent wherein the auther, Hildebrandt, synthesized 2-methoxymethamphetamine. Ethyl ether was used as the solvent. In the other post where I detailed the synthesis of amphetamines using Al-Hg under pressure, ethyl ether is used again. MeOH is obviously the better and more economical route, if it works, but just for the sake of intellectual pursuits, someone should try THF just to see what happens. Anyway, here are the references I mentioned above: AP 1960, 293, 67. BCJ 1968, 41, 506.
boingo Member	posted 01-14-99 10:14 AM BS: Why do you recommend less than an equimolar amount of NaOH vs. MeAm-HCl? peace, boingo
Rhodium Administrator	posted 01-14-99 11:05 AM Semtex: Ammonium nitrate is very good as a substitute for an ice bath. I dunno exactly how long the effect lasts, it is just that every time you dissolve an amount of the salt in water, the temp goes down a bit. I think the max cooling effect is down to -12°C.
ChemHack Member	posted 01-14-99 06:45 PM Why not add crushed ice directly to the mix? Surely there is enough alcohol in there to keep it all in solution. WARNING: I've never tried doing it, but I've been tempted...
Atomicdog Member	posted 01-15-99 01:28 AM Somebody PLEASE answer this: Can DCM be substituted for toluene as the extraction solvent in this 'Ritter' variation? If so, are there any differences in the workup? Toluene is hard to come by in my parts Thanks in advance, Atomicdog
Labrat Member	posted 01-15-99 09:47 AM Psychokitty, I checked the refs you gave: Arch.Pharm. 1960: this article was about reducing benzylic ketimines with Mg/MgI2 and Al/Hg. It's mostly about dimer-formation of the benzylic compounds. BSC Japan 1968: this article was about reducing (cyclo)-aliphatic imines. The imines were prepared by refluxing equimolar amounts of ketone and amine in the presence of KF. Yields were moderate. Lr/ P.S. If you have any other good refs, just tell them to me. You got my attention!
Bright Star Member	posted 01-15-99 11:33 AM I'm very close to wetting my pants. And I appear to be happy about it. Boingo! I've been doing this for several reasons... 1. The ketone will react with the MeAm salt ... just not as quickly .... 2. The excess of the MeAm. also ties up the excess water in the solution, preventing the ketone re-formation.... 3. Having a little MeAm.HCl always in there, leaves open the possibility that any ketone that does not react with the initial burst of free MeAm in solution, can (it is thermodynamically reasonable) react with salt.... Atomic Dog - sure DCM can always be used ... but Ritteran sunlight have an excellent point... One that I didn't even consider untill I read their posts... DCM gets EVERYTHING. All the unreacted ketone, all of the by products everything.... You'll have to distill the result. But apparently thats not true with toluene... I've never tried it, mind you, but I've always distilled after each procedure.... Chemhack - That might be alright... Weigh the ice though.... And the number of time you'll need to cool it might make it impractical ... This is great....
Atomicdog Member	posted 01-15-99 01:32 PM Brightstar: Interesting, the other reason I didn't like toluene was that I have no MgSO4 so drying would be difficult(Cacl2 maybe?) But DCM wouldn't have that problem, it would separate right out from the water layer and could be separated and then stripped off. The result could then be extracted with toluene(according to what I'm hearing) and the procudure finished. A way to dry without drying agents?
Beagle Member	posted 01-15-99 02:01 PM One of the great things about using toluene in a procedure like Sunlight's is that using drying agent is unecessary. Toluene forms an azeotrope with water, so as it is boiled off, it carries the water with it. The NaCl washes are still important though. But really, everyone should have easy access to Mg(SO4)2, since this is just epsom salts, after being baked in the oven.
Atomicdog Member	posted 01-15-99 04:02 PM Beagle: I think the small bit of water remaining is taken out becuase it would interfere with crystalization. Epsom salts! I'll have to come out of my cave more often! Hmmm... I have to admit, I've never used a drying agent for this. Do you simply pour the toluene/extract through the stuff? Oh, and what temp/ duration on the epsom salts?
chinacat Member	posted 01-17-99 02:38 PM Excellent post!! Just one question -- can MeOh be substituted for anhydrous EtOh in the Nitro-AlHg rxn? The ony write-up I've seen uses ethanol, if methanol can be substituted, well that makes my job easier, living as I do, in Canaduuuuh, where even denatured ethanol is next to impossible to get from hardware stores...Keep up the good work, fellow comrade in arms, every time I hear of a successful innovation in making drugs, i get all warm and tingly....much Love, Chinacat
chinacat Member	posted 01-17-99 02:39 PM Excellent post!! Just one question -- can MeOh be substituted for anhydrous EtOh in the Nitro-AlHg rxn? The ony write-up I've seen uses ethanol, if methanol can be substituted, well that makes my job easier, living as I do, in Canaduuuuh, where even denatured ethanol is next to impossible to get from hardware stores...Keep up the good work, fellow comrade in arms, every time I hear of a successful innovation in making drugs, i get all warm and tingly....much Love, Chinacat
psychokitty Member	posted 01-19-99 04:23 PM Labrat: I have many references that need to be found for me very badly. They are all listed in various parts near the end of the thread titled "The time has come -- OTC safrole synth" under the GENERAL DISCUSSIONS heading. Please, please, please help me. Those articles are the only thing that stands between me and my getting started on an actual lab protocol for the eugenol to allylpyrocatechol synthesis. Thanks. --Psychokitty
chinacat Member	posted 01-19-99 06:48 PM BTW - In a lot of ways, the ketone/AlHg rxn reminds me of the Nirtostyrene/LiAlH4/THF rxn - when I used to dream this dream, way back when, I used to crytallize out a phosphate (with phos. acid, obviously) directly from the thf, after basifying with NaOH/KOH -- always got very good results,made crystallizing so fucking easy, am spoiled now.... perhaps, what's -his-face was doing this too??? Just a thought....
sunlight Member	posted 01-21-99 06:04 AM Bright Star This method for crystallitation is great, but it isn't new. It avoids to work with HCl gas, neutralize the toluene-oil with Hcl, 25 % is ok, and then evaporate the azeotrope with stiring, and when the temp goes to 110 it's done. I evaporate even more toluene, and then when it is at 50 C or so I add acetone. The salt is then little brown, but it is easily cleaned to absolutley white crystal in the filter, adding small amounts of acetone that works as eluent of a chromatographic column, all the grabage goes out and you work less and more comfortable. I evaporate the toluene in my balcony, I don't have a fume hood. I bought methylamine 40 % some time ago, yes. You can mail me sunlight_is_here@hotmail.com
Kaff Member	posted 01-21-99 06:02 PM So how does one substitute MeNH2.HCl in Ritter's method instead of the 40% aqueous? I mean how much in grams?
sunlight Member	posted 01-24-99 10:22 AM Use the proportions in TS, or PIHKAL.
Kaff Member	posted 01-24-99 11:01 AM Because of the risk of mercury contamination, it might be a good idea to vacuum distill the final freebase, right? One could put 10ml or so of cooking oil in with the freebase so as you vacuum distill, you won't have to worry about the boiling flask going dry.The cooking oil has a higher BP than the freebase MDMA- I tested it on the stove.Crisco canola oil boils at well over 260 C which is as high as my thermometer goes. It's more work but mercury contamination is a bigger problem than low yields or other fuckups.
Atomicdog Member	posted 01-24-99 04:56 PM Kaff- ritter uses the NaCl washes to get rid of the mercury. I'd wash once with water, 3x with saturated NaCl, and then 2x with water again. Freebase MDMA boils at 100 to 110C at .4torr! Thats about 350C at normal pressure. Nobody really knows at what temp freebase MDMA decomposes at either, many including shlugin believed it began to decompose around 60C. Whan you distill freebase you're really just stripping off everything else. Hope this helps, and don't put cooking oil in your freebase! I have no idea how you would get it out.
Kaff Member	posted 01-24-99 06:14 PM Thanks for the advice about distilling... anyway,SomeoneWhoIsNotKaff finally decided to have a first try at the Al-Hg method,as posted by Ritter in this very thrad. S.W.I.N.K. followed this recipe very closely so what happened? Almost nothing. S.W.I.N.K. thinks it's because the HgCl2 must've been exposed to light at some point during the 6 months it's been hanging around, because after 12 hours of stirring and the addition of MUCH MORE than 1.5g of HgCl2, the 30g of aluminum (cut from pie plates) is still 80% intact. Since the problem is non-degradation of the Al. it must be because the HgCl2 is kaput.
Kaff Member	posted 01-24-99 06:36 PM I'm very interested in sunlight's method of crystallization without the HCl gas. S.W.I.N.K. cannot use the HCl gas because it's just too smelly. The sunlight crystallization seems a lot more practical, but I'm not sure how to adapt it to Ritter's Methanol amalgamation above.
ChemHack Member	posted 01-25-99 12:39 PM Kaff: Don't worry, when you add water it will take off. Try it and see!
Semtex Enigma Member	posted 01-25-99 02:11 PM Ritter: Osmium says that strong overhead stirring is nessisary for the Al/Hg. You said that stirring is only nessisary at the begining to get everything mixed. Do you think that mag stirring (2.5-3" stirbar) would be sufficiant for a 100-150g batch???
Atomicdog Member	posted 01-25-99 04:40 PM Semtex- Strong overhead stirring is nessesary for O's method. Everything I've read indicates that the force of stirring is directly related to Al thickness. Since O's method uses the thickest Al, it needs the strongest stirring. Shlugins method doesn't need strong stirring because it uses the thinnest Al. If you use pie plate thickness, you should be ok for a mag stirrer. Say, where can I find info on sunlights crystalization method?
Ritter Member	posted 01-25-99 09:44 PM kaff, are you sure the alcohol was heated to get the amalgamation going? If that didn't work then I'd guess your HgCl2 was bad, but that doesn't make sense because its a pretty stable material.
Kaff Member	posted 01-25-99 10:07 PM Ritter: Apparently HgCl2 is light sensitive, strong light can neutralize it. I didn't know this when I bought it. Is it possible to crystallize from the toluene phase without using the HCl gas method?
ChemHack Member	posted 01-25-99 11:55 PM [b]Kaff[\b]: What? The water didn't help?
ChemHack Member	posted 01-25-99 11:57 PM Are the UBB codes turned off or what? Why didn't I get BOLD in that last post ?
sunlight Member	posted 01-26-99 02:45 AM Well, I know that a friend of mine tried the Ritter method last week. She didn't follow the recipe exactly because she has some experience so he tried a variation. She amalgamated aluminium a la Shulgin to keep HgCl2 out. She evaporated all the methanol with the aspirator and a water bath before adding the NaOH solution. Then toluene and... Big emulsion, no two layers. She add then the methanol again and water, and then she could with patience extract the aqueous-alcoholic layer, using a lot of toluene. Patience with little emulsions. She told me that she prefers to filter and not breath toluene, and not use so quantitie of toluene, but this method works too. Finally she wash the toluene two times with water and one with brine, and acidified slightly toluene (she used more methanol to mix easily HCl) and evaporated with stiring a lot of it, then finally add the acetone and voila, good yields. The same than with ethanol.
Kaff Member	posted 01-26-99 04:28 PM ChemHack: Adding water isn't part of the Ritter recipe as it is written above. One uses only MeOH.
ChemHack Member	posted 01-26-99 04:46 PM "...a mixture of 60g ketone ang 75ml 40% aq MeNH2 is dumped in."
Kaff Member	posted 01-26-99 09:28 PM Sorry. You are right, ChemHack. In my dream I used MeAm.HCl made from the standard recipe. I used 130g of that instead of 75 ml aq MeAm.But I didn't add water.... should I have?
ChemHack Member	posted 01-27-99 02:18 AM I dunno, maybe the HgCl2 in my dreams is the weaker variety but when it just sits with alcohol and thick aluminum not much happens. BUT... When you pour in the aqueous solution of MeAm.HCl and NaOH all hell breaks loose! I'm not kidding! The shit goes nuts! Now, this could simply be due to the NaOH and the aluminum doing their little thing so I can't say for sure. The way to test it out would be to see what happens with just HgCl2, aluminum, and water.
equarius Member	posted 01-27-99 07:41 PM Kaff: What did you put your MeNH2HCl into then, did you just put it into the reaction flask? Also did you add any NaOH solution as required? What temp was your reaction done at, as I believe a certain temp must be reached in order for the Al to pulverize. Did you notice any white ammoniaish smelling gas comming off of the reaction. Can aquaous MeAmine solution be made by say dissolving the HCl form into 25% NaOH beforehand or will gas just be evolved?

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