Novel succinimide-based ionic liquids as efficient and sustainable media for methanolysis of polycarbonate to recover bisphenol A (BPA) under mild conditions

In this paper, several succinimide-based ionic liquids (SIILs) were developed and structurally characterized. They were used as multifunctional and sustainable media for selective conversion of polycarbonate (PC) into bisphenol A (BPA) via methanolysis method. The catalytic behaviors of SUB to the reaction, including the effects of SIIL structures, effects of reaction parameters, catalyst reusability, and interaction between SIIL and CH3OH were studied in detail. The [HDBU][Suc] comprising a 1,8-diazabicyclo[5.4.0]undec-7-ene cation and a succinimide anion exhibited superior performance compared to previous catalysts, and it afforded a complete depolymerization of PC with 96% BPA yield under mild conditions of 70 degrees C for 2 h in the absence of organic solvents and metal ions. The [HDBU][Suc] was easy to recycle and showed satisfactory reusability. Finally, a plausible mechanism for [HDBU][Suc]-catalyzed methanolysis of PC was presented in depth. (C) 2019 Elsevier Ltd. All rights reserved.