An approach to applicable inorganic polymers. I. Polycondensation by interaction of chloroborazoles and phosphorus esters

Trialkyl phosphates (3 mol.) form a hydrogen‐bonded complex with B‐trichloroborazole (1 mol.), and at 100°, this gives alkyl chloride and a solid borazole system with ‐OP(: O)(OR)2 structure attached to each boron atom. At about 200°, trialkyl phosphate is eliminated, and borazole rings appear to become attached by the structure ‐O.P(: O)(OR).O‐. Further polycondensation occurs at ∼500–800°, to give an infusible, insoluble and hydrolytically stable inorganic polymer containing boron, nitrogen and phosphorus. Related observations with N‐methyl‐ and N‐phenyl‐B‐trichloroborazoles are recorded. Equimolal systems, and dialkyl hydrogen phosphite‐trichloroborazole systems are described. Triphenyl phosphate reacted differently with B‐trichloroborazole, but did not react at all with N‐trimethyl‐B‐trichloroborazole. Techniques of gas chromatography, infra‐red spectroscopy and thermogravimetric analysis were used.