Surface functionalized ionic liquid polymer microspheres as efficient solid catalysts for chemical fixation of CO2 into cyclic carbonates

Abstract

3–5 μm ionic liquid polymer microspheres (TBB-Bpy) were synthesized with bipyridine and tetrabromotoluene through alkylation reaction and simple solvothermal method, and then a variety of alcohol amine, imidazole or pyridine was grafted onto the TBB-Bpy. And the catalytic activity of different supported ionic liquids was explored. After comparative experiments, ionic liquid polymer microspheres grafted with pyridine (TB-Py) were the most active catalysts for the synthesis of cyclic carbonates from epoxides and CO2. Morphology, structure, and stability of catalysts was explored by a variety of characterization methods (FT-IR, SEM, XPS, EA, and TGA). And various factors that affect the catalytic efficiency of TB-Py be researched, such as reaction temperature, pressure, catalyst dosage and reaction time. The selectivity and yield be analysis and detection by gas chromatography (GC-2010 Plus), under the reaction condition of 0.15 g catalyst, 80 °C, CO2 pressure of 1 Mpa, and 24 h, the yield of propylene carbonate can reach 96.52%. After 5 times of repeated use, the yield still has more than 90%, and the selectivity was always above 99%. It was easy to separate and reused after the reaction, and a reasonable reaction mechanism was proposed.