Catalytic conversion of CO2 into propylene carbonate in a continuous fixed bed reactor by immobilized ionic liquids

Abstract

In this study, functionalized composite catalysts, namely, ILs (ILX/(ZnBr₂)₂), with hydroxyl, carboxyl and amino groups immobilized on a molecular sieve (MCM-22) support were synthesized with the help of a silane coupling agent, 3-chloropropyltriethoxysilane (CPTES). Cycloaddition of CO₂ and propylene oxide (PO) was carried out in a fixed bed reactor. The results show that MCM-22-CPTES-[AeMIM][Zn₂Br₅] demonstrates the best catalytic properties for this reaction. A high selectivity and yield of propylene carbonate (PC) could be reached at 130 °C under a CO₂ pressure of 2.0 MPa, with a LHSV of 0.75 h⁻¹ and a molar ratio of CO₂/PO of 3 : 1. The yield stabilized at 61.6% after 50 h in the fixed bed reactor.