https://www.cas.cn/syky/202510/t20251027_5086297.shtml

https://www.nature.com/articles/s44286-025-00248-0

A team at the CAS Institute of Chemistry, in collaboration with teams from Beijing Normal University and Peking University, has proposed a “kinetic decoupling-recoupling” strategy, which efficiently converts polyethylene into ethylene and propylene without the need for precious metals or the addition of hydrogen. The yield reached 79%, exceeding the previously reported value, and developing a new pathway for polyethylene recycling.

The team constructed a two-stage kinetic model and designed a two-stage cascade reaction system. In the first stage, the layered self-supporting molecular sieve LSP-Z100 was used at 260°C to crack PE into hydrocarbon intermediates. In the second stage, a phosphorus-modified HZSM-5 molecular sieve catalyst was used at 540°C to selectively convert the intermediates into ethylene and propylene via a dimerization-βcracking reaction. By precisely controlling the kinetics of both stages, side reactions were suppressed and the selectivity of the target products was improved. The team further combined advanced characterization techniques such as synchrotron vacuum ultraviolet photoionization mass spectrometry and neutron powder diffraction to observe the C8 intermediate and reveal the reaction mechanism at the molecular level.

The research results were published in Nature Chemical Engineering.

The novel “kinetic decoupling-recoupling” strategy enables the efficient and highly selective conversion of polyethylene into ethylene and propylene.