A paper on copolymerization of carbonyl sulfide, written by a PhD student named Ming Luo from the laboratory of controlled polymerization and structure-properties of polymers, was published in Macromolecules.
As an important role in greenhouse gases, carbonyl sulfide (COS) is one of the chief culprits for acid rain and ozone depletion. We synthesized a regioregular and fully alternating poly(propylene monothiocarbonate) (PPMTC) through copolymerization of COS and propylene oxide (PO) by using (Salen)CrCl complexes as the catalysts and bis(triphenylphosphoranylidene)ammonium chloride ([PPN]Cl) as the cocatalysts. Through researches and optimizations, this catalyst system showed excellent performance during the process of polymerization. Firstly, the formation of cyclic by-products was completely inhibited, leading to 100% polymer product; secondly, its molecular weight was up to 25000 Da and the conversion rate of the monomer PO was nearly 100%; thirdly, this system could catalyze the fully alternating copolymerization of COS and PO; finally, the content of tail-to-head linkages of PPMTC was up to 98%, indicating that the copolymerization was highly regioselective. Significantly, different from the CS2-PO copolymerization system we reported before, the oxygen−sulfur exchange reaction in this copolymerization could be eliminated in the main, resulting in the absence of carbonate and dithiocarbonate units to ensure the synthesis of poly(monothiocarbonate) with definite structure. From the view of chemistry, this work also presented a highly regioslective copolymerization model involved two asymmetric monomers, enriching the research of monocarbon chemistry.
dx.doi.org/10.1021/ma401114m | Macromolecules 2013, 46, 5899−5904
Author：Ming Luo, Xing-Hong Zhang, Bin-Yang Du, Qi Wang, and Zhi-Qiang Fan
(By Lucy)
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