Efficient linking of two epoxides using potassium thioacetate in water and its use in polymerization

Here, we show that two epoxides can be efficiently linked using potassium thioacetate (AcSK) in water even at their imbalanced stoichiometric ratios. We found that the first reaction between epoxide and AcSK gave rise to an intermediate that underwent the second reaction with another epoxide with a reactivity much higher than that of AcSK. Time-dependent ¹H NMR measurements revealed that the rate constant of the second reaction was 31 times larger than that of the first reaction. Using this reaction, we succeeded in nonstoichiometric polymerization of a bifunctional epoxide. Furthermore, in the presence of a multifunctional epoxide, we obtained hydrogels and self-standing films. We expect that this straightforward and efficient reaction of versatile reagents, epoxide and AcSK, in water would lead to new applications of epoxides.