UC Berkeley Chemists Can Now Vaporize Plastic Waste Into Molecular Building Blocks

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1. This honestly doesn’t make much sense. There’s something wrong here, probably With the way the media is portraying it.

   How do you resect a polymer into consistent monomers that can be reused? First off, there’s no catalyst that can do this. Catalysts increase the speed of a reaction by decreasing the amount of energy that it takes to activate a chemical reaction. But they can’t induce a reaction that is thermodynamically disfavored.

   The problem is that the *sigma*-bonding between carbon and carbon and carbon and hydrogen is the “happiest” condition for these atoms. PP and PE are made entirely out of these bonds between carbon and hydrogen. Whereas, in the monomers from which these plastics are made, there is one carbon-carbon bond called a *pi*-bond that nature does not favor compared to a *sigma*-bond.

   There’s no catalyst that’s going to convert pure sigma bonding into a pi bond during the breakdown of a hydrocarbon. It’s just not what carbon “wants” to do in that situation.

   Yes, there are processes like catalytic cracking that do this. But they consume vast amounts of energy. And they generate a much “messier” product that contains a vast array of different hydrocarbons. It just doesn’t make sense that you could recreate the pure monomers from a hydrocarbon polymer.

   If you try to break down the hydrocarbon polymer chain in PE or PP, all you’ll get is smaller alkyl hydrocarbons like methane, ethane, etc.