TITAN- UND ZIRKONIUM-PYROPHOSPHATE, IHRE HERSTELLUNG UND VERWENDUNG

57 The invention relates to a new process for producing titanium IV and zirconium IV pyrophosphates, certain of which are new compounds, and their uses. The pyrophosphates are prepared by reacting a metal tetraester with phosphorus pentachloride, with or without the addition of an hydroxyl compound, such as an alcohol or a phenol. Depending on the molar ratio of the components, the compounds produced may contain cyclic or straight chain pyrophosphate groups and alkoxy groups attached to the metallic ion. In addition to forming new compounds, the process of the invention produces the desired products without difficult-to-separate by-products. The products of the invention are useful as flame-retardants, antioxidants, coupling agent, impact modifiers and processing aids, and the reaction for their preparation may be represented as follows:wherein M is titanium or zirconium; R is a monovalent hydrocarbon group optionally substituted with halogen or oxygen substituents; n is an integer from 1 to 4; m is an integer from 0 to 4; x is an integer from 0 to 2; q is an integer from 0 to 4; n is greater than or equal to m; n = p + m + q; x + m + 2p + q = 4; and when x is greater than 0, q is 0.