The science of Breaking Bad: Green Light

Breaking Bad : Season 3 : Episode 4 : “Green Light”

Walt on his last day in the classroom.

Walt on his last day in the classroom.

With Walt and Jesse’s post-cooking lives rapidly degenerating back to where they were, the infamous blue meth makes a reappearance on Albuquerque’s streets. In this post, I’ll be talking about reduction methods.

You can read more about this episode at AMC, IMDb and the A.V. Club.

Random thoughts

The scythe painted outside Walt’s house associates Tuco’s cousins with Los Zetas, as did their visit to the cave back at the start of the season.

Jesse’s mention of “two reflux condensers” presumably represents the maximum number that one person can comfortably manage – back in Four Days Out, Jesse and Walt were using at least six.

Reduction to product

Walt’s trademarked cooking method, as we found out in A No-Rough-Stuff Type Deal, involves the reductive amination of phenylacetone with methylamine. Walt triumphantly confronts Jesse on the reduction step by suggesting that he used platinum dioxide (PtO2) – this would have worked, but the purity could have suffered as the process is more technically challenging (note: PtO2 is used in other reductive amination and reductive alkylation cooking methods).

Jesse responds with some unexpected chemistry knowledge – he used a mercury-aluminium amalgam because the PtO2 is “too hard to keep wet”. The Hg-Al method is quite simple, making it a popular choice for cooks, though there is some risk of a runaway reaction if the reaction vessel is not attended to. Jesse’s comment about wetness may refer to the necessity of keeping the platinum catalyst away from air – PtO2 is reduced to Pt (the actual catalyst) in a hydrogen atmosphere, which will quickly form PtO2 again if it is exposed to air or an oxidising agent.

HT to Sprinkles, who predicted this very quandary in the comment thread for Four Days Out.

For background information on this topic, see the primer on redox.

Elements in the credits

Breaking Bromine
Bad Barium
Created Chromium
Bryan Cranston Bromine
AnNa Gunn Sodium
AAron Paul Argon
DeaN Norris Nitrogen
Betsy Brandt Beryllium
RJ MitTe Tellurium
BOb Odenkirk Oxygen
Giancarlo Esposito Einsteinium
JonAthan Banks Astatine
Christopher Cousins Cobalt
Steven MicHael Quezada Hydrogen
Carmen SeraNo Nobelium
Michael ShAmus Wiles Americium
Jolene Purdy Plutonium
KelleY Dixon Yttrium
Mark FreeboRn Radon
MiChael Slovis Carbon
Dave Porter Polonium
Sharon Bialy Sulfur
SherrY Thomas Yttrium
Diane MerCer Cerium
Moira Walley-Beckett Molybdenum
Thomas SchnAuz Gold
George Mastras Germanium
PeTer Gould Tellurium
Sam Catlin Calcium
John ShiBan Barium
Melissa Bernstein Beryllium
MicHelle MacLaren Helium
Mark JOhnson Oxygen
StewArt A. Lyons Argon
Sam CAtlin Astatine
Scott WiNant Sodium
Vince Gilligan Vanadium
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3 Responses to The science of Breaking Bad: Green Light

  1. Fungly says:

    Couldn’t he have opened up the Winnebago battery and added fresh sulfuric acid?

  2. John says:

    In a standard car battery, sulfuric acid is the electrolyte – electricity comes from the oxidation of lead to lead sulfate and the reduction of lead oxide to lead sulfate. Sulfate ions come from the sulfuric acid, so it does get exhausted when the battery is discharged.

    If Walt had added more H2SO4, he might have been able to squeeze out a little more battery life if the plates weren’t completely converted to PbSO4. It wouldn’t have been guaranteed, but it would certainly have been worth trying. Good thinking!

  3. John says:

    “The Hg-Al method is quite simple, making it a popular choice for cooks”

    It’s quite a bit more complicated than other reductions actually, as it involves multiple variables and forming the reducing agent insitu, it’s just easier to get the components for.

    The ‘anhydrous’ reductions do not need to be dry to a ppm standard, just ‘not soaking’, as a slight excess of sacrificial reducing agent will account for the remaining moisture.

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