Polyaniline supported Salen complex as highly active and recyclable catalysts for copolymerization of CO2 and epoxides

A new heterogeneous catalyst, polyaniline (PANI) supported SalenCr(III)Cl complex was investigated for the alternating copolymerization of cyclohexene oxide (CHO) with carbon dioxide (CO2) in the presence of [PPN]Cl (bis(triphenylphosphine)iminium chloride). The FT-IR, SEM/TEM, XRD, and XPS results indicated that SalenCr(III)Cl was successfully supported on PANI. The resulted catalyst (SalenCr(III)Cl-PANI) exhibited excellent catalytic performance for alternating copolymerization of CHO with CO2. Compared with the homogeneous SalenCr(III)Cl, the heterogeneous salenCr(III)Cl-PANI had obvious effect on microstructures of the copolymer, and the obtained polymer was found to be a linear alternating copolymer with narrower molecular weight distribution. The effects of various reaction parameters were also studied in detail, the reaction gives yield=12.91 g(Polym)./g(Supp). cat., M-n=12.21 kg/mol, M-w/M-n(PDI)=1.16 at 5.0 MPa CO2 pressure, 80 degrees C and 10 h. The SalenCr(III)Cl-PANI maintained good catalytic activity and selectivity after reuse. (C) 2016 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.