Patent ID: 8779135
Filing Date: 2014-07-15
Classification: C07F

Abstract:
1. A method for the manufacture of an aminohydroxy diphosphonic acid by combining a reaction mixture consisting essentially of the corresponding aminocarboxylic acid, P 4 O 6 and a sulfonic acid and performing the steps as follows: a: adding the P b: adding the P wherein the sulfonic acid is selected from homogeneous and heterogeneous sulfonic and polysulfonic acids; and the amino carboxylic acid and the P wherein X wherein X wherein X c: heating the reaction mixture at a temperature in the range of from 40° C. to 180° C. for a period of from 10 minutes to 30 hours, wherein the reaction contains less than 400 ppm of chlorine expressed in relation to aminohydroxy diphosphonic acid (100%).