Determination of the individual cyclic oligomers in equilibrium systems from ϵ‐caprolactam and water

Abstract

Abstract The content of cyclic dimer, trimer, tetramer in equilibrium polymerisates of ϵ‐caprolactam and water is determined by fractional sublimation of a methanolic extract, freed from the cyclic monomer and linear oligomers. The proportion of the cyclic dimer, trimer and tetramer in these products is 2/1/2 at 221.5° C and 5/2/7 at 253.5° C. The stability of the tetramer is tentatively explained on the basis of its molecular structure.