A simple and efficient synthetic method for poly(ethylene terephthalate): phenylalkyl pyrrolidinium ionic liquid as polycondensation medium

Abstract

A series of phenylalkyl pyrrolidinium ionic liquids (ILs) ([YBPy][X], Y = NO₂, CH₃, F, H; B = benzyl, phenethyl; X = Tf₂N) were synthesized and found to be environmentally benign reaction media for the preparation of poly(ethylene terephthalate) (PET). ILs with specific functional groups had high thermostabilities and showed interesting properties in synthesizing PET at lower temperature (190–240 °C) and pressure (500 Pa) compared to conventional ILs. PET with M_w up to 1.9 × 10⁴ g mol⁻¹ was obtained. The ILs can be easily separated and reused after simple purification except for the PF₆⁻ ILs. This process provides a valuable and environmentally friendly alternative to the currently available method for the preparation of PET in industry.