The reaction of 1 mole of melamine with 2 moles of acetic anhydride leads to diacetylmelamine (DAM), which is a mixture of two constitutional isomers: 90% N,N′-DAM and 10% N,N-DAM The reaction of 1 mole of DAM with 1–8 moles of oxiranes (ethylene and propylene oxides) was studied by 1H NMR spectroscopy. At the molar ratio of substrates 1: ∼ 2, no N,N′-diacetyl-N,N′-bis(2-hydroxyalkyl)melamine was formed, but the product of its intramolecular rearrangement, N,N′-bis(2-acetyloxyalkyl)melamine, was found. The latter reacted with the excess of oxiranes to appropriate tetrafunctional polyetherols containing s-triazine rings.
