| Autor: |
Niknam, Fatemeh, Denk, Alina, Buonerba, Antonio, Rieger, Bernhard, Grassi, Alfonso, Capacchione, Carmine |
| Zdroj: |
Catalysis Science & Technology; 2023, Vol. 13 Issue: 16 p4684-4692, 9p |
| Abstrakt: |
In this study, a new family of dinuclear chromium complexes (1–3) containing bis-thioether-diphenolate ligands has been introduced for the binary copolymerization of carbon dioxide and epoxides and ternary copolymerization of the latter with phthalic anhydride. Complex 1(0.1 mol%) in combination with (bis(triphenylphosphine)iminium chloride) (PPNCl, 0.5 mol) at 45 °C and 20 bar of CO2showed high regioselective copolymerization to polypropylene carbonate (PPC) with conversion (up to 91%) and selectivity (up to 95%). The data presented in this work have consistently shown that complex 1displayed higher catalytic activity in copolymerizing epoxides with CO2than complexes 2, 3, and the analogous mononuclear 4. At the same time, complex 1showed good catalytic properties in the terpolymerization of epoxides/CO2/phthalic anhydride among the tested complexes 2and 4. In the case of cyclohexene oxide and vinylcyclohexene oxide, a selectivity of more than 99% towards polycyclohexene carbonate (PCHC) and polyvinylcyclohexene carbonate (PVCHC) with a TOF as high as 41 h−1in the poly(ester-block-carbonate) was observed. Notably, a conversion higher than 99% towards the polyester block was also observed for all the studied epoxides. A bimetallic intramolecular cooperative mechanism was proposed for the copolymerization of propylene oxide and CO2based on the first-order dependence with respect to complex 1by the kinetic investigations. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
