Ethyl Corporation

James R Mitrano

J Robert Adams, Jr

Matthew K Juneau

Polymer-grade cyclic phosphonitrilic chloride trimer can be obtained from crude cyclic polyphosphonitrilic chlorides by forming a solution of the crude cyclics, water washing the solution, distilling solvent to form a hot concentrate, cooling to form a precipitate and distilling the precipitate to form polymer-grade trimer.

Phosphonitrilic chloride trimer purification

Cyclic phosphonitrilic chloride trimer suitable for polymerization to light colored, high molecular weight, linear polyphosphonitrilic chloride can be made by (1) reacting PCl.sub.5 and NH.sub.4 Cl in an inert solvent (e.g. monochlorobenzene) to form a solution of a low molecular weight linear and cyclophosphonitrilic chlorides, (2) evaporating solvent to form a concentrate, (3) adding water and cooling the mixture to precipitate cyclic trimer, (4) separation of the trimer precipitate and (5) distillation of the separated trimer.

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Baton Rouge, LA, United States of America

James R Mitrano