Scientists from the University of Illinois Urbana-Champaign, UC Santa Barbara, and Dow have developed a breakthrough process to transform the most widely produced plastic — polyethylene (PE) — into the second-most widely produced plastic, polypropylene (PP), which could reduce greenhouse gas emissions (GHG). 

“The world needs more and better options for extracting the energy and molecular value from its waste plastics,” said co-lead author Susannah Scott, Distinguished Professor and Mellichamp Chair of Sustainable Catalytic Processing at UCSB. Conventional plastic recycling methods result in low-value plastic molecules and, thus, offer little incentive to recycle the mountains of plastic waste that have accumulated over the past several decades. Turning polyethylene into propylene, which can then be used to make a new polymer, is how we start to build a circular economy for plastics.”

“We started by conceptualizing this approach and demonstrated its promise first through theoretical modeling. Now, we have proved experimentally that it can be done in a way that is scalable and potentially applicable to current industry demands,” said co-lead author Damien Guironnet, a professor of chemical and biomolecular engineering at Illinois who published the first study outlining the necessary catalytic reactions in 2020. 

The new study, published in the Journal of the American Chemical Society, announces a series of coupled catalytic reactions that transform PE, which is #2 and #4 plastic, which make up 29 percent of the world’s plastic consumption, into the building-block propylene, which is the key ingredient to produce PP,  also known as #5 plastic, whic accounts for close to 25 percent of the world’s plastic consumption. 

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