Terpolymerizations of CO₂, Propylene Oxide, and Various Epoxides Using a Cobalt(III) Complex of Salen-Type Ligand Tethered by Four Quaternary Ammonium Salts

Abstract

Terpolymerizations of CO 2 /propylene oxide (PO)/cyclohexene oxide (CHO), CO 2 /PO/1-hexene oxide (HO), and CO 2 /PO/1-butene oxide (BO) were carried out without the formation of cyclic carbonates and ether linkages with a cobalt(III) complex of a Salen-type ligand tethered by four quaternary ammonium salts ( 1 ). The activities were excellent, in the range of (0.62−1.6) × 10 6 g/mol-Co (TOF, 4400−14 000 h −1 ). In all three of terpolymerizations, the data for the PO mole fractions in the feed ( f PO ) and the polymers ( F PO ) fit the Fineman−Ross plot well to determine the monomer reactivity ratios. The linear dependencies of the T g ’s of the polymers on the mole fractions of the third monomers ( F CHO, F HO, and F BO ) were observed with the relationships of “ T g (°C) = 81 × F CHO + 40”, “ T g (°C) = −62 × F HO + 38”, and “ T g (°C) = −27 × F BO + 38”, respectively. The decomposition temperature of the resin increased when the third monomer was employed. The GPC data indicated that the polymer chains grew in an immortal passion from four 2,4-dinitrophenolates as well as the two 2,4-dinitrophenols in 1 . High molecular weights ( M n ) above 200 000 were attainable because of the high activities.