Title of Paper:Bis-ammonium immobilized polystyrenes with co-catalyzing functional end groups as efficient and reusable heterogeneous catalysts for synthesis of cyclic carbonate from CO2 and epoxides

Hits:

Date of Publication:2016-01-01

Journal:RSC ADVANCES

Included Journals:SCIE、EI

Volume:6

Issue:3

Page Number:2217-2224

ISSN No.:2046-2069

Abstract:A series of novel bis-ammoniumionic liquid immobilized polystyrene (BisAm-i-PS) heterogeneous catalysts with co-catalyzing functional end groups of -CH2COOH, -CH2CH2OH, and -CH2CH2NH2 were synthesized for the cycloaddition reaction of CO2 and epoxides without any additional co-catalyst and organic solvent. All the ammonium immobilized catalysts showed high selectivity. Bis-ammonium immobilized catalysts were more efficient than single-ammonium ones. The yield was further increased by introducing the functional end groups. Both -CH2COOH and -CH2CH2OH terminated BisAm-i-PS catalysts achieved high activities (yield: > 99%), while the -NH2 terminated one had a slightly lower activity (yield: 97.3%) under the same reaction conditions. The effects of different parameters, such as the halide anions of the catalysts, reaction temperature, initial pressure and reaction time were also investigated with -CH2CH2OH terminated BisAm-i-PS (BisAm-OH-i-PS) as the catalyst. Under optimal reaction conditions (1.2 MPa, 130 degrees C and 2.5 h), BisAm-OH-i-PSs with 2Br(-) and 2I(-) showed very high efficiencies. For each of them, propylene carbonate selectivity and yield were more than 99% and 99%, respectively. In addition, the catalyst possessed good stability, and both catalytic activity and selectivity were always more than 99% for 5 times of recycle tests.