Hydroxylation-Depolymerization of Oxyphenylene-Based Super Engineering Plastics To Regenerate Arenols

Super engineeringplastics, high-performance thermoplastic resins,show high thermal stability and mechanical strength as well as chemicalresistance. On the other hand, chemical recycling for these plasticshas not been developed due to their stability. This study describesdepolymerization of oxyphenylene super engineering plastics via carbon-oxygenmain chain cleaving hydroxylation reaction with an alkali hydroxidenucleophile. This method is conducted with cesium hydroxide as a hydroxysource and calcium hydride as a dehydration agent in 1,3-dimethyl-2-imidazolidinone,which provides hydroxylated monomers effectively. In the case of polysulfone,both 4,4 & PRIME;-sulfonyldiphenol (bisphenol S) and 4,4 & PRIME;-(propane-2,2-diyl)diphenol(bisphenol A) were obtained in high yields. Other super engineeringplastics such as polyethersulfone, polyphenylsulfone, and polyetheretherketonewere also applicable to this depolymerization.

Automated summary

This study investigates the depolymerization of oxyphenylene super engineering plastics using cesium hydroxide as a hydroxy source and calcium hydride as a dehydration agent. The reaction takes place in 1,3-dimethyl-2-imidazolidinone and effectively produces hydroxylated monomers. High yields of 4,4'-(sulfonyldiphenol) and 4,4'-(propane-2,2-diyl)diphenol were obtained in the case of polysulfone, and similar results were observed for other super engineering plastics such as polyethersulfone, polyphenylsulfone, and polyetheretherketone.