NMR spectra of cyclic formals formed during the early stage of the copolymerization of trioxane and ethylene oxide

During the early stage of the copolymerization of trioxane and ethylene oxi de, we found the formation of three novel cyclic compounds: 1,3,5,7-tetraox acyclononane (TOCN), 1,3,5,7,10-pentaoxacyclododecane (POCD), and 1,3,5,7,1 0,13-hexaoxacyclopentadecane (HOCP). These novel cyclic compounds were new direct reaction products of 1 mole of trioxane and 1 mole of ethylene oxide , 1 mole of trioxane and 2 moles of ethylene oxide, and 1 mole of trioxane and 3 moles of ethylene oxide, respectively. We compared the H-1-NMR and C- 13-NMR spectra of each cyclic compound and precisely assigned the signals o f each spectrum using NOESY (nuclear Overhauser enhancement spectroscopy) a nd HETCOR (heteronuclear correlated spectroscopy). We also compared the H-1 -NMR spectra of POCD and HOCP with the corresponding cyclic formals with on e oxymethylene unit, diethylene glycol formal (DEGF) and triethylene glycol formal (TEGF). Interestingly, we found that DEGF and TEGF, which have only one oxymethylene unit, showed no proton splitting of the oxyethylene units , while POCD and HOCP, which have three consecutive oxymethylene units, hav e split signals for the oxyethylene units.