Alternating copolymerization of carbonyl sulfide and Cyclohexene Oxide catalyzed by zinc-cobalt double metal cyanide complex

This paper describes the first example of alternating copolymerization of carbonyl sulfide (COS) with cyclohexene oxide (CHO) via heterogenous catalysis of a nano-lamellar zinc-cobalt(III) double metal cyanide complex (Zn-Co(III) DMCC), providing an efficient method for converting COS to poly(cyclohexene monothiocarbonate) (PCHMTC) with an alternating degree up to 93%. The number-average molecular weight (Mn) of PCHMTC was 6.5-25.0 kg/mol with polydispersities (PDIs) of 1.6-2.1. The productivity of the catalyst was up to 970 g polymer/g catalyst (5.0 h). The oxygen-sulfur exchange reaction (O/S ER) caused by Zn-Co(III) DMCC was largely suppressed when the reaction was performed at 100-110 °C in the presence of THF or CH2Cl2, and thus the selectivity of the monothiocarbonate over carbonate linkages was up to 98%. The mechanisms of the copolymerization and O/S ER were proposed based on the ESI-MS, GC-MS and FT-IR spectra. The obtained PCHMTC is highly transparent and exhibits good solubility in various organic solvents, high Tg of 112 °C, initial decomposition temperature of 214 °C and high refractive index of 1.705.

Poly(cyclohexene monothiocarbonate) was efficiently synthesized by the copolymerization of carbonyl sulfide(COS) with cyclohexene oxide (CHO) via Zn-Co(III) DMCC catalysis.160