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: S_N1, where the -OH group of methanol dislodges to form a methyl cation (?!?!), followed by subsequent ammonia bonding; or S_N2, 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.

Say it With Me - Fluorophlogopite!

 

Source: Nails, Inc.

The other night, my special someone and I were sitting on the couch, and I was introduced to the "new hot thing" in fashion: magnetic nail polish. 


Apparently, as several DIY blogs explain, the "secret magnetic particles" contained in the polish "activate" in a magnetic field. Of course, a quick glance at the ingredients shows just plain iron powder, which, when dolled up with several layers of lacquer and clays, creates ripple patterns on the nail surface. 


But hey, with companies like LCN and Sephora charging to the tune of $16 USD (for a 10 mL bottle!) the price is comparable to standard lab reagents.

Sodium Zeolite A
Source: British Zeolite Association

But I digress. Looking through the ingredient list of the Trafalgar Square color, I felt totally out of my depth. Luckily, C&EN's "What's That Stuff?" feature came to my rescue, at least for a few of the common components (thanks, Carmen!). 


Of course, there's nitrocellulose, the shiny, potentially explosive major player, found for a time in movie film, gun cotton, and auto paint. Clays familiar to the bench chemist (bentonites, hectorites) make their way in as thickeners, including the fantastically-named bulking agent fluorophlogopite. This synthetic aluminosilicate calls to mind zeolites, inorganic structures used in fuel upgrading, gas storage, and catalysis.

One of the great features of chemical research: Even though you think you've seen it all, there's a surprise around the corner. After nitrocellulose, this particular brand uses an interesting copolymer of adipic acid, neopentyl glycol, and...trimellitic anhydride? I'd seen the first two, but never this, an interesting "triple-reactive" crosslinker (looks like maleic anhydride went for a crazy aromatic spin) which was first isolated in 1830 by Liebig and Wöhler, two heavyweights of 19th Century German chemistry. 


This tetracyclic curing agent, an all-star of the coal tar chemistry in the early 1900s, found use as a curing agent in polymers as early as the '30s. New uses in the last 15 years include protein charge ladders and luminescent materials research.


Update (1/21/2012): Over at Chemical Novelty, Travis has dug deep in the patent literature to really see what this product is all about. Go have a peek!