Verfahren zur Herstellung von Phosphonsaeuren bzw. deren Salzen mit mindestens 2 Phosphoratomen im Molekuel

摘要

A process for the preparation of a phosphonic acid containing at least two phosphorus atoms comprises treating an acylation product of phosphorous acid, subsequent to its formation, with water at an elevated temperature, preferably above 60 DEG C. and expediently below 160 DEG C., steam being used above 100 DEG C. Volatile products may be distilled off; steam used in the process may also be used to effect this. The products are believed to be of the type R being the residue of the carboxylic acid RCOOH. The products may be converted into alkali metal or ammonium salts. The acylation products may be prepared by the reaction of phosphorous acid with a carboxylic acid halide or anhydride or mixtures thereof or from PCl3 and the carboxylic acid. Examples describe the preparation of products from phosphorous acid and acetyl chloride, acetic anhydride, mixtures of acetyl chloride and acetic anhydride, propionic anhydride, butyric anhydride, caproic acid chloride and acrylic acid chloride. Salts are prepared in some cases.