Metathesis, molecular redistribution of alkanes, and the chemical upgrading of low-density polyethylene

A new strategy for polyethylene (PE) deconstruction via alkane metathesis is presented, in which WOx/SiO2 catalyzes the olefin metathesis reaction step. Zeolite 4 A is an essential component to protect the metathesis active sites from poisoning by in-situ-generated oxygenates in a batch reaction system. High conversion of 1-hex-adecene (96%) and n-hexadecane (92%)-surrogates of long-chain molecules-demonstrates the high reactivity of WOx/SiO(2 )metathesis catalyst for olefin and alkane metathesis reactions, respectively, at moderate reaction temperatures of 300 ? for 2-3 h. Pretreatment temperature and length of the short n-alkane-chain solvent significantly affect the metathesis reactivity and selectivity. Results for the deconstruction of low-density PE (LDPE) in n-decane demonstrate a remarkable potential for PE upgrading with the advantages of short reaction times (3 h), the low mass ratio of solvent to LDPE, and the production of solid products with narrow molecular weight distributions.

Automated summary

A new strategy for polyethylene deconstruction via alkane metathesis using WOx/SiO2 catalyst has been proposed, showing high reactivity and selectivity for olefin and alkane metathesis reactions. The method has the potential for PE upgrading with short reaction times and the production of solid products with narrow molecular weight distributions.