Molecular-level swelling behaviors of poly (ethylene terephthalate) glycolysis using ionic liquids as catalyst

Ionic liquids (ILs) are considered as the high-efficiency catalysts for PET glycolysis. However, insight into the swelling behaviors for PET glycolysis with IL still remains seldom. Hence, temperature-dependent interfacial properties and catalytic performance for PET glycolysis with [Cho][OAc] catalysts were investigated using molecular dynamic (MD) simulation and experiments. MD results indicate that [Cho][OAc] can enhance the PET swelling in ethylene glycol (EG), especially at high temperature, contributing to the enhanced conversion of PET. Strong interaction between EG and [OAc]- as well as PET and [Cho]+ can intensify the access of reaction sites between PET and EG, important to the high-efficiency PET glycolysis. Furthermore, experimental results confirm that the PET conversion catalyzed by [Cho][OAc] increases with elevated temperature with almost 100 % PET conversion and 66.7 % BHET yield at 180 ℃, which strongly supports MD results. The information provides an essential understanding about the swelling for PET glycolysis with IL catalysts.