LAUSR

Abstract Multifunctional alkanolamines without metals or halides were designed as catalysts for the synthesis of propylene carbonate (PC) by the cycloaddition of CO2 and propylene oxide (PO). New catalysts were synthesized in a one-step, low-temperature reaction. Among the multifunctional alkanolamine catalysts, bis(methylpiperazinyl)triol (Catalyst 1) showed the best performance, with a 96% yield of PO in 3 h at 120 °C and 10 bar using 1 mol% catalyst. A 90% yield of PO could be obtained using 5.60 mol% of Catalyst 1 under mild conditions (100 °C and 5 bar). A reaction mechanism was proposed based on the synergistic effects between the hydroxyl and amine groups in one multifunctional molecule. The effects of the reaction parameters (temperature, CO2 pressure, and catalyst loading) on the yield of PC were interpreted using response surface methodology. The metal- and halide-free catalysts will facilitate an environmentally friendly process for the application of other carbonates.