Polymorphism and Mechanochemistry of 5-Phenoxymethyl-2-oxazolidinone

Abstract

5-Phenoxymethy1-2-oxazolidinone (PMO), obtained by the reaction of tris (2, 3-epoxypropyl) isocyanurate (TEPIC) with phenol, gave dimorphic crystals, A- and B-forms, or their mixtures (Fig.1). The composition of the mixture depended upon solvents of recrystallization, grinding conditions and thermal treatment. In solution two forms gave the identical IR and NMR spectra, but in solid phase they showed marked differences in the IR spectra (Fig.2), X-ray diffraction patterns (Fig.3), and DTA curves (Fig.4). The transition temperature from Bto A-form was determined by the methods of microscopy and DTA measurement.
No difference in the pyrolytic behavior was observed in these two forms. The activation. energy and order of the pyrolysis were calculated from the TG curves to be 23.0 kcal/mol and zero, respectively.