Then, the only remaining trick is identifying which crystals have which enantiomer (and as these crystals are translucent and "optically active", observing the polarization pattern of light shone through the crystals will identify which are which). This means that all White has to do is slow the evaporation of solvent and subsequent cooling of the pan, letting the largest possible crystals form. This means, for the non-chemists, that each enantiomer molecule prefers to crystallize with others of the same chiral species, so as the solution cools and the solvent is evaporated off, the D-methamphetamine will form one set of homogeneous crystals and the L-methamphetamine will form another set. In the case of methamphetamine, this resolution is among the easiest, because methamphetamine forms a "racemic conglomerate" when crystallized. The advantage is that most of the methods are pretty cheap and easy the disadvantage is that your maximum possible yield is 50% (unless you can then run a racemization reaction on the undesireable half to "reshuffle" the chirality of that half then your yield increases by 50% of the last increase each time you run this step on the undesirable product). This seems to be the way it works in the real world. The remaining route, then, is chiral resolution let the reaction produce the 50-50 split, then separate the two enantiomers by some means of reactionary and/or physical chemistry. I don't remember any mention of using organocatalysis or biocatalysis, but these are possible. Metal complexes with chiral ligands can be used to selectively catalyze production of one enantiomer, however the aluminum-mercury amalgam is again achiral.
Recipe for crystal meth tv#
There are other methods of asymmetric synthesis, however none of them seem applicable to the chemistry shown or described on TV either none of the reagents or catalysts mentioned would work as chiral catalysts, nor are they bio- or organocatalysts.
However, again as you show, phenylacetone is achiral, and so the P2P process cannot take advantage of this method.
As you state, starting with an enantiomerically-pure sample of a chiral reagent (pseudoephedrine) as the starting point allows you to preserve the chirality of the finished product, provided the chiral point is not part of any "leaving group" during the reaction. The pseudoephedrine method for methamphetamine employs one of the more common methods of asymmetric synthesis, called "chiral pool resolution". Reaction processes designed to do this are known as "asymmetric synthesis" reactions, because they favor production of one enantiomer over the other. In this case, White wants D-methamphetamine (powerful psychoactive drug), not L-methamphetamine (Vicks Vapor Inhaler). White could have used to obtain an enantiomerically pure product?įirst, the best yield would be achieved by selectively producing one enantiomer instead of the other. Since the show might not want to tell us the answer, I am wondering what what other possible methods Mr. In fact, he raises this topic more than once in the series. White clearly knows about the issue of producing the correct enantiomer. While his blue-colored product is considered by his customers to be exceptionally pure, Mr. Racemic methamphetamine was obtained by the Winnebago-based chemists by reductive amination of P2P using methylamine and hydrogen over activated aluminum. White uses his knowledge of chemistry to move to an alternative synthesis starting with phenylacetone (also know as P2P or phenyl-2-propanone): However, making (S)-methamphetamine on a large scale is limited because it is hard to get sufficient quantities of (1S,2S)-pseudoephedrine. This method features the use of an optically active starting material to make an optically active end product, (S)-methamphetamine. White uses the common small-scale route starting with (1S,2S)-pseudoephedrine (the active ingredient in Sudafed®️). In the highly-rated TV series, Breaking Bad, Walter White, a high school chemistry teacher recently diagnosed with cancer, takes to making the illicit drug, crystal meth (methamphetamine), by two main routes.įirst, along with his RV-driving accomplice, Jessie Pinkman, Mr.
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