Trimer process

摘要

Polymer-grade cyclic phosphonitrilic halide trimer can be obtained by (i) reacting ammonium halide with phosphorus pentahalide in an inert solvent containing pyridine, substituted pyridines or mixtures thereof or hydrogen halide complexes thereof, (ii) washing the solvent phase with an aqueous alkali metal hydroxide and (iii) crystallizing cyclic trimer and/or distilling the cyclic trimer to obtain polymer-grade trimer.