Author Topic: methylamine synthesized ala Bright Star´s:it´s good enough? (Read 1853 times)

sassa · « **on:** June 17, 2010, 03:12:08 PM »

Last these day I have been proving new writeups of amination. Always I have used nitrometane as source of metylamine, with good succes but not perfect results as for yields.
Some time ago I did a few hundreds of grams of metylamine following the bright star´s method that never used. That is to say, with only 1 filtering of the residual ammonium chloride and without doing any type of purification with chloroform or recrystallization.
I am going to prove the variant of reduction with methylamine, methanol,.... proposed by Roundbottom: " Osmium/BrightStar Al/Hg Methylamine Reductive Amination ", posted on Rhodium,since the yields are really interesting, and the process is way more simply and easier than Methyl's man method. I am going to use a scale 10X minor to try with few amounts of ket.
My question is with regard to the quality of the produced methylamine following the bright star´s method:i know that is not pure, something about 95 %, and it must contain significant quantities of ammonium chloride and other amines.. But the production of mda as a side product would not be a problem. Only wish that yields were not lowering in excess due to this lack of purity of the methyilamine.10-20% less hydrocloride would not be a problem to handle.It´s posible to need to add some extra mg. of this methylamine to assure a propper amount of it?
Some experience using methylamine done with this process?

mumbles · « **Reply #1 on:** June 17, 2010, 05:00:03 PM »

You may want to clean up that methylamine with hot isopropanol, there is a good 4 page-ish thread on this on sciencemadness ('good way to methylamine' ?). I've read roundbottom's take on it as well. Roundbottom's yields were high and he used smaller flasks for the same amount of ketone which is handy.

sassa · « **Reply #2 on:** June 22, 2010, 11:29:50 PM »

Proved that methylamine(without cleaning) and worked fine.Roundbottom write-up of the reductive amination with methylamine/AL/HG/MeOH rocks!!both about lower solvents needed,easy procedure and good yields!Seems too that the product it´s a little more trippier about effect. i have never obtained the expected yields from Methyls´man method ,but of course i supposed my problem wastoo on crystallization with gas.Anyway,this write-up works way easy.
Only one thing.The methylamine gas smell

.It´s way stronger than produced Using nitromethaneas methylamine source,using exact the same equipment and conditions(cold water with a reflux condenser):Methyalmine gas come over easy.Maybe will try a better and longer reflux condenser.i Really hate that smell that fix on the room for days.Anyway,the product and yields were the expected

.
Only maked diferrent the crystalization to try another method than gas and worked fine.Extract the amine from the final toulene with 10 %HCL and let evaporate water at room Temo:Takes days,but works fine!
I recommend this write-up as the first to try if it´s your first AL/Hg.Of course at this day is easier get nitromethane than make Metylamine,but it´s really hard to go wrong.

Osmium/BrightStar Al/Hg Methylamine Reductive Amination

http://www.erowid.org/archive/rhodium/chemistry/redamin.os-bs.html

jon · « **Reply #3 on:** June 24, 2010, 11:55:29 PM »

methylamine produced with paraforamldehyde 2 moles and 1 mole nh4cl gives good results the key is temperature control and vacum to eliminate co2 to drive equilibrium to the right the temperature should be held in exactly the 104-106 range just sufficient vacum to pull co2 is important too much and the reactants evaporate the vacum is adjusted so that the co2 evolution is visible from the top of the reaction soup ie. no co2 should be seen bubbling from the bottom.
under these parameters only methylamine is recovered in 2-3 crops under vacum reduction.
no ammonium chloride is precipitated indicating high yeild and efficiency and ease of workup as well.
the methylamine produced in this manner is pure enough to be used without workup it's purity is indicated by the fact that it is not very hygroscopic.
any further questions feel free to ask

madprossor · « **Reply #4 on:** June 26, 2010, 06:06:19 AM »

wow, Jon. the OrgSyn procedure was always my reference but it definitely gives incomplete conversion of the NH4Cl (and slow workup on a small funnel). i didn't know it was possible to get a close-to-complete conversion without having problems with dimethylation. VL mentioned slight vacuum, he specified 20 inches of Hg, which confused some people (who tried 20 mmHg and failed) and is still much higher than what you're talking about.

i disagree that pure MeNH2.HCl is not so hygroscopic though. i had relatively pure MeNH2.HCl from the OrgSyn procedure and it turns into a puddle after a couple hours of air exposure. NH4Cl in contrast is much less hygroscopic. did you try to recrystallize the methylamine hydrochloride from alcohol to see it's purity? i understand of course even a good bit of residual NH4Cl should not interfere at all in the next reaction.

jon · « **Reply #5 on:** June 26, 2010, 12:46:40 PM »

hi madprossor have'nt seen you here.
umm pure methylamine is hygroscopic but it can be handled without turning into a puddle.
when you crop the methylamine you start to see the scummy looking film and you stop the vacum reduction.
i put a fan on it to cool it all the way to room temp i find if i did'nt do this i wind up filtering endlessly.
because nh4cl always crystalizes first there's a sharp distinction between the two.
i did'nt bother checking purity you can look at it's crystall shape and that tells all.
the way to keep temps in that range is by reacting it in a boiling saturated solution of table salt it boils exactly 106 i bunged 32 ounce beer bottles to an aspirator and pulled a very gentle vacum if the vacum is to high you will know because it will simply foam out.
but that's the way to do it without tieing up glassware.
another minor detail careful with that soda glass don't cool it suddenly.
and lid the pot so the steam heats up the bottles also otherwise the temp gets a little cool and nothing happens.
you can always tell by the rate of co2 generation.
all i did was vacum filter then plop it in the vac dessicator for a day.
the halosafrole process takes a lot of methylamind escpecially if one is doing a couple hundred grams of mdma.
and in this case purity is'nt that critical i would'nt think a little ammonium chloride would stop the reductive amination from happening either.

madprossor · « **Reply #6 on:** June 27, 2010, 04:57:09 AM »

beer bottles, heh. we made some hydroxylamine in champagne bottles- similar concept.

i remember the OrgSyn procedure being tedious. alcohol is added and distilled off to remove water. nh4cl is cropped off once. the next two crops give MeNH2.HCl contaminated with nh4cl. the MeNH2.HCl is extracted from the nh4cl with boiling dry isopropanol then precip'ed.

i was wondering quantitatively how much the use of vacuum improves yields and decrease the amount of residual nh4cl. i guess it doesn't matter though any improvement is worth a try, after which all will become clear.

salat · « **Reply #7 on:** June 27, 2010, 01:30:50 PM »

Quote

i had relatively pure MeNH2.HCl from the OrgSyn procedure and it turns into a puddle after a couple hours of air exposure

In humid climates try 10 min or less!!

salat

jon · « **Reply #8 on:** June 27, 2010, 05:55:33 PM »

ummm with vacum i cropped no ammonium chloride just like the refs say, temperature is also key that's why the salt water baths you can't fuck it up this way.
it's qauntitative try it and see.
and salat, i enjoy reading your posts i think you're smarter than you let on.

salat · « **Reply #9 on:** July 04, 2010, 12:42:55 AM »

thanks, I'm smart enough to know what I don't know. My husband is the chemistry whiz and I learn from him and comment on what he's doing that's why you have this combination of newbie and advanced in my writing. I'm good at researching, but just getting my feet wet with the real thing.

He's wondering why he can't wash methylamine with chloroform to remove the small amound of dimethylamine he got (flask too big so he overshot his temperature slightly) - waiting for some butyl alcohol to arrive otherwise.

I'll research it tomorrow. Spent all day moving my lab stuff to another room and am tired - was just checking this thread to see if there was anything helpful for him.

salat

jon · « **Reply #10 on:** July 04, 2010, 01:17:28 AM »

dcm and tce also rid the dimethlamine.
that's why i recommend salt water baths (saturated salt water) they hold tempertures at 106 and you never overshoot temps..
beats watching a thermometer.

salat · « **Reply #11 on:** July 04, 2010, 01:18:01 PM »

will dcm work on an aquaeous solution of methylamine hcl? Stuff formed a cake on the bottom of the flask so he dissolved it with water to get it out. He said he went to 110 on purpose after the reaction was done. I don't always understand what he is saying. He's going to do an experiment to try it and see, we'll let you know.

salat

jon · « **Reply #12 on:** July 04, 2010, 01:49:37 PM »

i don't see why not but he's just going to have to reduce it under vacum again mine as well rinse it in the bushner funnel.
next time tell him to use ethanol.

salat · « **Reply #13 on:** July 04, 2010, 06:05:03 PM »

The methylamine is sitting in the bottom of the sep funnel so I guess it worked - looks white. He said ethanol for the reaction or to dissolve it to get it out of the flask? Don't ask about trying to dry ethanol around here or anything else for that matter. Glasses fog just walking outside.

At any rate he's going to have to do the washing & drying stuff anyway this is just step 1.

salat

XBee · « **Reply #14 on:** July 04, 2010, 07:03:32 PM »

Yeah, yeah - I messed-up the Brightstar MeAm synth! I've been playing with "the classic" synth to better understand it, and didn't keep my eye on the ball (so to speak). SO... LARGE flask, SMALL single neck, LOTS of VERY hard product adhering to flask bottom and keeping both my spinbar and thermocouple tube HOSTAGE! ON THE BOTTOM no less!

<sigh> that's what I git for not warming a beaker for over 7 years... but life's good now - VERY good

Anyhow - I FINALLY logged on to say something other than the intro. Oh, yeah - if anyone wants to know, I've had a great deal of successes - I know a LOT of things that DON'T work!

Bee-was

jon · « **Reply #15 on:** July 05, 2010, 03:28:47 AM »

ethanol to dissolve it out of the flask.
and as a solvent to separate the methylamine from the ammonium chloride.
hey pm me you'll probably need a little advice on preping dry alcoholic solns of methylamine it's tricky if you don't have things figured out.
was he asking wheather to use ethanol in the sn2 reaction?
it works but i don't like it. the yeilds are better with ipa.

XBee · « **Reply #16 on:** July 11, 2010, 05:55:59 AM »

Got it covered, Jon... just got the gallon of n-Butyl alcohol I've been waiting for.... just the THANG for cleaning it up without needing to mess about (in an EXTREMELY humid place!) making absolute EtOh - more like OH! Anywho... I'm not exactly trying to get to a "destination" - as I sed, I'm trying to understand the reaction dynamics. Clearly, one wants to move the puppy "to the right", i.e. eliminate the formic acid, which is the immediate product that's clogging the reaction pipe (given that this is an equilibrium deal). Mother nature to the rescue! It spontaneously (under the right conditions!) decomposes into CO2 (how nice!). THAT can be hurried up with some vac (as wuz mentioned earlier in the thread). Oh, BTW - in the Brightstar writeup, they "figger" you'll have about 3-4% NH4CL and perhaps as much di-MeAm, which for all intents and purposes one "shouldn't notice" were one to (HORRORS!) actually commit an illegal act. My trials seem to agree, tho I didn't do the quantitative analysis to confirm (if that answers the original posts' question).

The OTHER way I thought of getting rid of the formic was to add MeOH, which would POOF! make a VERY LOW BP Methyl formate. Uh... didn't pan out very well. Now, since I got myself into a bind with the last tests, I'm fiddle-forting about with off-the-wall ideas once the stuff had (allegedly) finished reacting. I say "allegedly" because I DID get a small crop of NH4CL, so I either had too much to start with, or I screwed the pooch along the way. I'm also displeases with the near-orange color of the final brew - this I suspect was from the loooonnngg ramp-up time to get to 104c (about 4 hours to get there, then 5 hours AT 104, give or take 0.2c). Temp control I've GOT DOWN - just playing with the reaction to REALLY understand it.

Hope that answers all those burning questions no one's asked yet

just buzzing 'round

lugh · « **Reply #17 on:** August 30, 2010, 03:17:41 AM »

The best way to dry methylamine hydrochloride is with a centrifuge as described in Vogels and Organic Syntheses

no1uno · « **Reply #18 on:** August 30, 2010, 04:23:28 AM »

Just requested two papers on the acid/thermal decomposition of urotropine/hexamine. I've done the reaction, but I'd dearly love to know if there is a way to add excess ammonium salts to stop the formaldehyde/formic acid production. That shit stinks the place down.

Ok the references are in (Java is a wonder), hydrolysis of hexamine with acetic acid gives acetamide and formaldehyde, two VERY FUCKING USEFUL chemicals which are a bitch to acquire easily. I'll throw up the paper on the Hoffman Degradation of Acetamide to give methylamine as well (given that acetamide is easily made via hexamine). Any input on how to rapidly form paraformaldehyde from the formaldehyde generated by the reaction?

PS Another paper on the production of methylamine from ammonium chloride and 40% formalin solution, it is attached.

PPS Has anyone got a selective preparation of dimethylamine? Right at the moment alkaline hydrolysis of various weed-n-feed-type products (present as about 500g/L in several combinations) as the dimethylamine salts seems like the best "selective" route... I want it to try out the dimethylchloramine + phosphine = RP + dimethylammonium chloride reaction, but dimethylamine:borane looks tasty too.

NeilPatrickHarris · « **Reply #19 on:** October 30, 2010, 06:29:01 AM »

Quote from: jon on June 24, 2010, 11:55:29 PM

the methylamine produced in this manner is pure enough to be used without workup it's purity is indicated by the fact that it is not very hygroscopic.
any further questions feel free to ask

quick question about how hygroscopic MeAm HCl is. if one were to titrate a solution of MeOH + MeAm(g) then drive off the MeOH with heat and no vacuum, would that be an issue? its melting point is 230C so no worry there but what about it sucking up moisture from the air while you're trying to drive off the MeOH? i hear the more heat you apply (within reason) the dryer it will be so perhaps an oil bath set to 150C would be reassuring to get it nice and dry?

Author Topic: methylamine synthesized ala Bright Star´s:it´s good enough? (Read 1853 times)

sassa

methylamine synthesized ala Bright Star´s:it´s good enough?

mumbles

Re: methylamine synthesized ala Bright Star´s:it´s good enough?

sassa

Re: methylamine synthesized ala Bright Star´s:it´s good enough?

jon

Re: methylamine synthesized ala Bright Star´s:it´s good enough?

madprossor

Re: methylamine synthesized ala Bright Star´s:it´s good enough?

jon

Re: methylamine synthesized ala Bright Star´s:it´s good enough?

madprossor

Re: methylamine synthesized ala Bright Star´s:it´s good enough?

salat

Re: methylamine synthesized ala Bright Star´s:it´s good enough?

jon

Re: methylamine synthesized ala Bright Star´s:it´s good enough?

salat

Re: methylamine synthesized ala Bright Star´s:it´s good enough?

jon

Re: methylamine synthesized ala Bright Star´s:it´s good enough?

salat

Re: methylamine synthesized ala Bright Star´s:it´s good enough?

jon

Re: methylamine synthesized ala Bright Star´s:it´s good enough?

salat

Re: methylamine synthesized ala Bright Star´s:it´s good enough?

XBee

Re: methylamine synthesized ala Bright Star´s:it´s good enough?

jon

Re: methylamine synthesized ala Bright Star´s:it´s good enough?

XBee

Re: methylamine synthesized ala Bright Star´s:it´s good enough?

lugh

Re: methylamine synthesized ala Bright Star´s:it´s good enough?

no1uno

Re: methylamine synthesized ala Bright Star´s:it´s good enough?

NeilPatrickHarris

Re: methylamine synthesized ala Bright Star´s:it´s good enough?