- "The methylamine keeps flowing, no matter what. We are not ramping down. We're just getting started. Nothing stops this train."
- ―Walter White
Methylamine (CH3NH2) is an organic compound. The gas is a derivative of ammonia, but with one H atom replaced by a methyl group. It is the simplest primary amine. It is sold as a solution in methanol, ethanol, THF, and water, or as the anhydrous gas in pressurized metal containers.
In Breaking Bad, methylamine is used by Walter White and Jesse Pinkman as they use reductive amination of phenylacetone (P2P) to yield methamphetamine - a process they devised to circumvent the need to buy pseudoephedrine. This P2P and methylamine-based cook produces what became infamously known as "Blue Sky" in the American southwest. Though methylamine-based methamphetamine was traditionally considered as a less refined version next to its pseudoephedrine-based counterpart (Hank Schrader describing it as "biker meth"), Walt's chemistry expertise helped eliminate any differences in quality between the two methods.
During the course of the series, methylamine is not synthesized by either Walter White or Jesse Pinkman, and thus the search for methylamine for use as a methamphetamine precursor is a large plot point throughout the series. For example, Walt and Jesse once stole methylamine from a warehouse, and, on a later date, from a freight train. The source of methylamine during their cook sessions in the superlab was Golden Moth Chemical.
Methylamine is prepared commercially by the reaction of ammonia with methanol in the presence of a silicoaluminate catalyst. Dimethylamine and trimethylamine are coproduced; the reaction kinetics and reactant ratios determine the ratio of the three products. The product most favoured by the reaction kinetics is trimethylamine.
- CH3OH + NH3 → CH3NH2 + H2O
In this way, more than 400M kg are produced annually.
In the laboratory, methylamine hydrochloride is readily prepared by treating formaldehyde with ammonium chloride.
- NH4Cl + H2CO → [CH2=NH2]Cl + H2O
- [CH2=NH2]Cl + H2CO + H2O → [CH3NH3]Cl + HCOOH
Another route involves refluxing sulfamic acid with methanol for several hours, which yields ammonium methyl sulfate, which rearranges at high temperature to form methylamine sulfate.
The colorless methylammonium salt can be converted to the amine by the addition of strong base, like NaOH:
[CH3NH3]X + NaOH → CH3NH2 + NaX + H2O
The methylamine gas is dried using a basic desiccant, like anhydrous sodium hydroxide.
After realizing they couldn't find the supplies needed to continue the production of meth, Walter White and Jesse Pinkman decide to steal a barrel of methylamine from a lab in order to be able to continue ("").
Walt and Jesse continue to use the barrel for cooking sessions, after Saul Goodman gives Walt an advice to cook meth "while the sun still shines," Walt and Jesse spend two days cooking in the desert, using most of the methylamine inside the barrel. Jesse eventually comes to the realization that Walt's imperative to cook the entire barrel before the methylamine became denatured was a ruse to build their inventory, and that the methylamine would not spoil.
Walt is forced to destroy the RV, since Hank Schrader's investigation led him to find the RV and almost discover that Walt is behind the production of the Blue Sky. The RV is destroyed in a junkyard, and it is assumed that the barrel of methylamine was destroyed with it.
Walt, Jesse, and Saul are talking about how they are going to find more methylamine, realizing they need it prior to beginning to cook again. Later, it is revealed that Lydia Rodarte-Quayle provided Gus with methylamine in the past. Mike Ehrmantraut asks Lydia if she can still get some methlyamine and Jesse is sent to the Madrigal warehouse to get a barrel. Lydia and Jesse discover that the barrel had a bug from the DEA, preventing them from using it, but Lydia gives them another plan to steal methylamine from a freight train.
Walt, Jesse and Todd Alquist are able to steal methylamine from the train, and pump it inside a large plastic tank, which they kept it in the headquarters of Vamonos Pest. At one point, Jesse and Mike decided to sell their part of the methylamine to another dealer, so Walt hid the tank inside the Car Wash he owns, and convinced Mike to let him keep using the methylamine for production.
- Although the show makes a big fuss out of getting methylamine over the other important precursors, like phenylacetone, in reality methylamine is much easier to synthesize than the other meth precursors, and neither of methylamine's precursors are hard to find or restricted. Apart from the writers not wanting to show viewers how to make illegal drugs, there are a couple of in-universe explanations for this plot point:
- One possibility is that Walt didn't know that methylamine was a List I precursor, though this is unlikely, as it has been on the list since 1991, and Walt told Jesse that some of the items on the shopping list are difficult to find, so he would know;
- He quickly wanted a bulk amount of the simplest precursor so he could focus on making phenylacetic acid and phenylacetone, which are more complicated to make;
- Due to his ego, he found it "beneath him" to make methylamine, as it is a reaction so simple any high school kid could do it, so instead he wanted to get it by other means, especially illegal ones, to satisfy his narcissism, which fits his persona;
- Pure methylamine is a gas at standard conditions, but in the show we see that it's presented as a liquid. The most likely explanation is that the methylamine is either dissolved in water or some other solvent, or in water as salt (they replace the methylamine from the train with water after all) especially since no character from the show ever complains about the odor of methylamine, which should be putrid fish-like odor. However, in the scene where Jesse reads Walt's shopping list, Walt asked for anhydrous methylamine, which would not be stored in barrels, but rather gas cylinders. It's likely that Jesse couldn't find anhydrous methylamine, and instead settled for solution of methylamine, which Walt would purify to get anhydrous methylamine.
- Likewise, if the methylamine from the train was anhydrous, they wouldn't have been able to open the seals that easily, and if they added water, the whole methylamine would have fumed and boiled from contact with the relative warm water, as well as reaction with it, which forms methylamine hydrate. The escaping methylamine hydrate fumes would potentially poison or even kill Todd, Jesse and Walt, who were near the tank car, essentially ending their plan.
- Methylamine on Wikipedia