Novel ring-expansion reaction between cyclic formal and ethylene oxide

Novel direct reactions between trioxane and ethylene oxide were discovered, and three novel cyclic formals were isolated and identified. These novel cyclic compounds clarified the initiation mechanism of the copolymerization of trioxane and ethylene oxide. This type of direct reaction is not only limited to the reaction between trioxane and ethylene oxide, but it was also found to be generalized to the reaction between the cyclic formal and ethylene oxide.