Phosphonitrilic chloride polymers
AssigneeEthyl Corporation
InventorHsueh M. Li
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Abstract
Linear phosphonitrilic chloride polymers are produced from linear phosphonitrilic chloride oligomers by means of a two-step process. In the first step a mixture of linear phosphonitrilic chloride oligomer having an average degree of polymerization of at least 4 is heated with an excess of ammonia or ammonium chloride. Cyclic phosphonitrilic chloride oligomer formed during the course of the first step is removed from the reaction mixture. After the removal of the cyclic oligomer the reaction mixture is subjected to the second step which involves heating the mixture in an inert liquid solvent (optionally in the presence of ammonia or ammonium chloride) whereby the molecular weight of the linear phosphonitrilic chloride polymer is increased.
Claims27
A process for producing linear phosphonitrilic chloride polymers from linear phosphonitrilic chloride oligomers of lower molecular weight which comprises:
- (a) heating a mixture of linear phosphonitrilic chloride oligomer having an average degree of polymerization of at least 4 and an excess of ammonia or ammonium chloride at a temperature in the range of about 130.degree. to about 250.degree. C. while concurrently removing hydrogen chloride and concurrently or subsequently removing cyclic phosphonitrilic chloride oligomer from the heated reaction mixture;
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- (b) after the formation of cyclic phosphonitrilic chloride oligomer has essentially ceased and after removal of the oligomer, heating the reaction mixture in an inert liquid solvent at a temperature in the range of about 130.degree. to about 250.degree. C. to increase the molecular weight of the dissolved linear phosphonitrilic chloride polymer.
Dependencies are inferred from the claim text.