Oxygen/Sulfur Atom Exchange Copolymerization of Carbon Disulfide and Propylene Oxide by a Highly Effective Heterogeneous Berlin Green Catalyst

I n this study, we report that Berlin Green (FeFe-BG) framework exhibits superior performance in the catalytic coupling of carbon disulfide (CS 2 ) and propylene oxide (PO) to generate a random copolymer containing thioether, propylene monothiocarbonate and ether units. Oxygen and sulfur atom exchange was detected in polymeric and cyclic thiocarbonate byproducts and utilized to modulate the copolymerization of CS 2 and propylene oxide. The coupling of PO and CS 2 was selective for copolymer formation under various reaction conditions. 1 H and 13 C NMR spectroscopy determined two distinct polymer linkages and two cyclic byproducts. Copolymer number average molecular weights ranged from 6.4 kg/mol to 10.5 kg/mol, with a comparatively low polydispersity of 1.3–1.7. The CS 2 /PO molar feed ratio had a significant impact on the O/S exchange process; the ratio of cyclic thiocarbonate byproducts could be efficiently regulated by tuning the CS 2 molar feed ratio.