No abstract

Benzene, chlorobenzene, c-xylene and naphthalene are phosphonated by hexagonal phosphoric anhydride in a temperature range of about 275-325°. A primary reaction product is formed by addition of one molecule of the aromatic compound to one molecule of P4Oio with opening of a covalent P-O bond. In the cases of chlorobenzene, o-xylene and naphthalene there are also formed secondary reaction products which are phosphonic anhydrides of the type (ArPCbb. The primary reaction products are insoluble in the aromatic compound while the secondary ones are soluble. Both the primary and the secondary products give the phosphonic acid when hydrolyzed and the phosphonic dichloride when chlorinated with phosphorus pentachloride.