Thursday, September 27, 2012

Methylamine Pseudoscience

Please see updates, posted below original piece. Thanks!

Pseudoscience strikes again. About a month ago, over at Slate's Brow Beat culture blog, Mr. Daniel Lametti - he of 'Ph.D.-Waste-Of-Time' fame - wrote a piece analyzing a recurring Breaking Bad plot device: the theft of large quantities of methylamine for the characters' illegal methamphetamine operation. The meat of the post:
"As a post on Reddit asks, since Walt is a brilliant chemist, couldn’t he just synthesize the stuff himself?
Yes, and pretty easily. There are many different ways to make the compound; with little more than an introductory organic chemistry class, you could probably synthesize it in your kitchen sink. (Brow Beat doesn’t recommend trying to make methylamine in your kitchen sink). Chemically speaking, methylamine is just ammonia with one hydrogen atom swapped out for a methyl group—a carbon atom and three hydrogen atoms. Without getting into too much detail, an easy way to achieve this swap* is to “bubble” ammonia (a gas) through methanol (a liquid) that’s been laced with a dehydrating agent like Silica gel. You could probably buy these chemicals at Home Depot and CVS. Silica gel packets are often packaged with new shoes and electronics to keep them dry."
Wait, huh? Let's start from No.

As a practicing synthetic organic chemist, I agree with the statement that silica gel dehydrates solvents by water absorption. Sure. But I've heated plenty of alcohols in the presence of silica gel, and 99% of them don't spontaneously lose water! (That would be a rocking olefin synthesis, if it worked...)

Methylamine: Easy as hooking up five pressurized reactors in your kitchen sink.
Credit: Albermarle
Let's put this on firm scientific ground. The reaction in question, a nucleophilic substitution, could theoretically occur by two mechanisms: SN1, where the -OH group of methanol dislodges to form a methyl cation (?!?!), followed by subsequent ammonia bonding; or SN2, where the ammonia directly displaces the -OH, one step, no intermediates.

In this scenario, both are extremely unlikely, especially at room temperature and pressure.

Now let's talk practicality: which company will sell you a cylinder of ammonia gas for 'home use?' (Not Home Depot). How will you get your methanol? What's the plan to isolate the (volatile, stinky) methylamine from the complex mixture of compounds this theoretical reaction produces?

Well, how do companies make methylamine? Albemarle technical documents to the rescue! Seems that mixing methanol and excess ammonia at 300-500 degrees Celsius, under pressure, over a zeolite catalyst will produce an equilibrium mixture of methylamine, dimethylamine, and trimethylamine (favored). After fractional distillation, the trimethylamine can be streamed over an amorphous silica / alumina catalyst to disproportionate it back into methylamine.

Not a kitchen sink in sight.

Update, 8/17/13 - This piece jumped back into the spotlight as Breaking Bad winds down its 5-season run. Thanks to Dylan at WaPo's Wonkblog for linking back here.

Commenters have taken issue with my description of the reaction, so I've slightly changed the text for clarity (methods / mechanisms, "forms" cations, oxidation...)

8/19/13 - Arguments have cropped up, in multiple forums, about reagent availability, feasibility of the chemistry at small-scale, mechanism, purification, etc. I blame myself for not refining my argument well enough in the original post. Very directly, I'll re-state the major arguments:

1) The silica gel + methanol + ammonia route will not produce methylamine as stated
2) Although an experienced chemist *could* produce methylamine using different reactions in a kitchen sink, he will by no means produce enough to support a burgeoning criminal enterprise which manufactures methamphetamine at multi-kilo scale.

*Curious - Appended at the bottom of the essay is a thanks for Prof. Adam Braunschweig, faculty at NYU now UMiami.. To what extent did Prof. Braunschweig proofread this post? Did he sign off on the "kitchen sink silica gel" concept in the middle? I can't possibly imagine that he thoroughly vetted this essay.

29 comments:

  1. That said, methylamine is in fact not so hard to synthesize. Methylamine.HCl can be synthesized via hexamethylenetetramine and conc. HCl & not extremely excessive heating. Perhaps that's a bit closer to a "kitchen sink" procedure.

    ReplyDelete
    Replies
    1. Oh, sure, I'll concede that there are ways to get fairly pure compound, and production of the salt would help with isolation / purification. However, I think the transformation discussed in the Slate piece would have issues with selectivity, ease of handling, and reagent sourcing.

      Delete
  2. Um, trimethylamine disproportionates into methylamine? What's the other product? Pentamethylamine??

    ReplyDelete
    Replies
    1. Methanol.

      Me3N + 2 H2O -> MeNH2 + 2 MeOH

      As the author states, trimethylamine is favored (tetramethylammonium hydroxide will also be produced to some degree, but at elevated pressure and temp this will split back into trimethylamine and methanol) because increasing amine substitution (more methyl groups) makes it more reactive.

      If I was Walt in season 5, I would make friends with a top-fuel (nitromethane) drag racer team and under-the-table a few gallons of fuel. Since dragsters use up >10 gallons per run, making a few extra disappear wouldn't be a problem. Nitromethane can be reduced to methylamine in a number of ways, all of which are potentially explosive, but possible. This method will not produce di- or trimethylamine, and fractional distillation of the products is easy (relatively).

      Source: top of my Chemistry class, recent graduate, working researcher, and beloved O-chem tutor. Fuck Meth, powder caffeine all the way. Great show though, gotta love the attention to scientific detail.

      Delete
  3. TMA + NH3 <=> DMA + MMA
    DMA + NH3 <=> 2 MMA

    ReplyDelete
  4. See Arr Oh is quite right - The proposed kitchen sink methylamine synthesis is nonsense. But if I can be a little pedantic...

    "could theoretically occur by two methods: 1. SN1, where the -OH group of methanol dislodges from the methyl cation (?!?!), followed by subsequent ammonia bonding"

    should be:

    "could theoretically occur by two **mechanisms**: 1. SN1, where the -OH group of methanol **is released to form a** methyl cation [the cation wasn't there before...] (?!?!), followed by subsequent ammonia bonding"

    Also, disproportionation is a redox process but I think what you have here is equilibration in the presence of ammonia without changes oxidation level (at least if Anonymous' comment is the actual process...)

    Sorry to be pedantic!

    ReplyDelete
    Replies
    1. No, you're quite right. This was an old piece, and I'll mark edits accordingly. Thanks!

      Delete
  5. "How will you get your methanol?"

    Methanol is very easy to procure, both in retail amounts and industrial amounts. It's used as fuel for many yacht stoves, added to race car fuels along with a dozen other uses in industry.

    I bought mine at a Canadian Tire store in 4 a liter jug.

    hexamethylenetetramine is also used as a fuel, backpackers and campers and may be a part of many homes emergency preparedness kit. It usually comes in a small square package with a small emergency stove. It burns well even in the rain and wind. Too stinky for use inside.

    I have no idea if hexamethylenetetramine is available in large amounts. It seems to me that doing so might trigger a visit from Homeland Security because it is used in the production of some explosives.

    ReplyDelete
  6. What you're talking about is usually called Hexamine. And yeah, it is used in explosive manufacture. The reaction of methanol and ammonia do yield it.

    But what motivated me to comment, is that no "practicing" synthetic chemist worth his salt would discount a production method because it's performed at high temperatures and pressures in an industrial environment.

    Anyone who's been in the trade longer than it took to get his degree, should know that those conditions are not required for the reaction to proceed on an acceptable scale. A business performing a reaction repeatedly will benefit from shifting the equilibrium as far as possible toward the desired product. A small lab performing a reaction can suffice with less.

    I'm unsure what to think when he goes on to mock the final reaction mixture. It would appear he is the first "practicing synthetic chemist" to have never performed a synthetic reaction. Product isolation is routine and straightforward.

    This author merely contributes an entry level analysis which serves to do little more than confuse the layperson.

    ReplyDelete
    Replies
    1. Dear Anon:

      I'm sorry you find my "entry-level analysis" so sorely lacking. If you have a more learned contribution, I invite you to write it up and send it to me. I'll post it if I believe you're somehow better informed on the matter than I.

      Sound fair?

      Delete
    2. I see no reason to do that when the synthesis is a grignard with methylIMINE. You've misunderstood the chemical, making this entire discussion moot.

      Delete
    3. Dear Anon:

      If Walt and Jesse are (according to the script) engaging in a modified P2P cook, then they're reacting phenylacetone with methylAmine, followed by some sort of enantioselective reduction. A twist on a classic method, in use by clandestine labs since the '60s.

      http://www.vice.com/read/a-comprehensive-guide-to-cooking-meth-on-breaking-bad

      Now, please, tell me where you see a Grignard in P2P. Are you perhaps thinking of imine formation onto phenethyl aldehyde, followed by some sort of (Lewis acid-catalyzed) MeMgBr addition?

      Delete
  7. *Edit*

    "2) Although an experienced chemist *could* produce methylamine..., he (or she) will by no means produce enough..."

    ReplyDelete
    Replies
    1. The use of the masculine singular pronoun here isn't meant to exclude women from illicit drug chemistry.
      By all means, a female chemist could certainly produce methylamine by this route.

      Delete
  8. Being that it is a television show they obviously had to pick an ingredient whose manufacture in a large and profitable scale is debatably too difficult to produce in the time frame of the story. That being said it is obvious to conclude that they had to steal it or buy it in mass quantities to supply the demand influx they created. It really comes down to basic economics and not chemistry

    ReplyDelete
  9. wow, the snide, pretentious, dweebishness on evidence in some of these comments is truly repellant and I wish I hand't bothered to click through to this blog post, let alone read it. Way to go, arguing amongst yourselves like socially tone-deaf Aspies...

    ReplyDelete
  10. Ah, for the good old days of P2P when labs were fairly clean. I remember one raid in Evergreen CO, where the product was 98% and white, of course; not blue. After P2P went on the watch list and everyone switched to phenylacetic acid, it got really foul. One lab in Farmers Branch TX in an industrial park was so bad you could smell it just driving by in the street. I kept one set of tennis shoes in a bag in my garage just for lab raids. Twice thru the wash and several months out in the Texas sun and they still stunk like horsepiss. I was happy to retire before the Sudafed - phosphorus days really got going.
    --A retired DEA Senior Forensic Chemist

    ReplyDelete
  11. I read this entire post in Walt's voice.

    ReplyDelete
  12. hello I'm not a chemist but i made the synthesis but i think it won't work becaus of the methylamin will diseapear if the temerature is higher than -6°C So it's a but problem and i have one even worse ammina will deseapear if the temperature is HIGHIER THAN -38°C yeah LESS FORTYEIGHT sorry for caps but it's a big problem so you see well it isn't true it can work (because methylamin will but with wather and NH3 will be NH4OH) well if you could tell me how to get some methylamin (i study chemistry ...)(But making drugs it isn't my goal at all but it could be fun to chalenge ourself and a make a true synthesis )

    ReplyDelete
    Replies
    1. Haha hahahahahah ahahahahaha

      Delete
  13. ok im gonna jump in here with my own taught knowledge of making legible psychotherapy designer drugs that eventually lead to world peace day dream as a pisces birthdayina few days glad i found this ...... WELL AS FOR BREAKING BAD FOR ME THAT WAS MY SHOW... lets call him joe.. Joe got into alot of bath salts while on a speed bindge for months and spent 20 grand on the shit motel to motel sex eat sex eat shoot shoot repeat repeat no sleep days tanked smoked out 11 prescribed pharmaceuticals and 11 warrants... next state over.... so im in RHODE ISLAND where nothing is banned and this shit is outlawed 90 percent else where... whatever thats way before the chemistry knoledge comes n all that but ive read tons of chemistry books under the influence of amphetamine knock offs that even made u bug out and learned a whole deal of a lot now its research chemical study and effect and im not a lab rat says joe... as for dreams of blue meth the closest clandestinaly making it with basic knoledge of the chemicals alone is not enough... neither is you completing the reactions correctly and knowing weither or not you screwd up this is also alot of math equation and measuring in this.... i will say this Methamphetamine is nuerotoxic ECSTASY/MOLLY is MDMA methyldioxymethamphetamine also nuerotoxic .... Dextroamphetamine is not... amphetamine is not therefore... MDDA would not be nuero toxic nor would MDA. MDE etc..

    ReplyDelete
    Replies
    1. Please consider reading this subject material while NOT under the influence of learning-distorting dopamine stimulants. The ability for direct electrical stimulation of a dopaminergic reward pathway to constrain learning to favor repetitive tasks over big-picture learning has recently been demonstrated in patients with Parkinson's disease. Recall that abuse of dopaminergic stimulants can induce symptoms (and even the onset) of Parkinson's. Do be careful.

      The nEUrotoxicity of psychoactive dopaminergic materials is related more to dosage than the identity of the compound. Methamphetamine and MDMA, both widely considered by the layperson "all-neurotoxic, all the time", are actually not when administered in acceptably small dosages. One widely publicized (and several-years-retracted) study on MDMA in Rhesus monkeys "confirming neurotoxicity at standard dosages" used the more potent methamphetamine instead of the similarly named MDMA. From this study, it is only reasonable to conclude that MDMA is less neurotoxic than meth (a foregone conclusion). The neurotoxic potency of such materials cannot be arm-chair estimated merely by looking at the structure.

      Moreover, the highly substituted PEA analogues found in the deplorable "bath salts" are likely more stressful to the brain than the more easily metabolized cocaine, though this cannot be claimed with certainty as these newer materials have not been investigated in any controlled trial. On the other hand, the biological activity of illegal materials such as "meth" and cocaine are fairly well understood, as they have been in wide use for well over 50 years.

      Pure methamphetamine, like many pure psychoactive compounds, is a white powder. Any other color implies presence of an impurity. Also, many adulterants are used which are also white powders. Bottom line: without expensive analysis, the purity of any illegal white powder cannot be known. To ensure higher purity, the educated speed-freak (lol!) may elect to recrystallize their substance of choice in the proper solvent after performing an acid-base extraction.

      Delete
    2. This comment has been removed by the author.

      Delete
    3. From a drugs forum post :

      "The addition of the N-methyl group to the methylated phenylethylamine results in a decreases in molecular polarity, greatly enhancing penetration of the blood brain barrier, allowing direct stimulation of the postsynaptic catecholamine receptors.

      Whereas the methylated phenylethylamine (Amphetamine) is an inhibitor of catecholamine breakdown and storage.

      I'm not shore how much information your after, is that what your after?

      Read more: http://www.drugs-forum.com/forum/showthread.php?t=174881#ixzz33xGuPxN9"

      Delete
  14. Methylamine can be made very easily be dissolving creatine monohydrate in Gatorade and incubating at room temperature for a few days.

    ReplyDelete
  15. I got methylamine sauce as a topping at Dairy Queen. Just ask for it.

    ReplyDelete
  16. wow. this is the smartest comment thread i´ve ever seen. Actually, this is the only smart comment thread i've ever seen.

    ReplyDelete
  17. Check out MetaFilter.com then, you might like it. Anyway, it's funny that everyone's like "it wouldn't be that hard to get XYZ and make it," but nobody really makes everything that wouldn't be all that hard to make or they would have no time to do anything else. Acquiring huge amounts of any of the precursors to methylamine they stole (and far more quantity to steal than the final product of course) would look suspicious or require lots of risk, i.e. lots of individual purchases from "smurfs" or other people who you expose yourself to in the process. If they want to make methylamine they might as well have gotten into the methylamine business and sell it to Gale and Gus.

    That would've been a clever twist actually, where your "laundering scheme" and "clandestine operation" combine into a legit super lab where Walt produces the next super chemotherapy or nanotechnology components and saves the world with another sinister one underneath producing something less sketchy to transport by train and so forth. Something for a parallel universe, I wouldn't change a thing to the original.

    ReplyDelete
  18. Formaldehyde and ammonium chloride? Isn't that one way to do it? Heat mixture to remove methylal and methylformate and then vacuum distill to get methylamine? No?

    ReplyDelete