Abstract: Process for the isolation and purification of free acids, starting from their salts, by electrodialysis which involves the use of:i) an electrolytic cell of four compartments, in which the two compartments adjacent to the two electrodes are separated from the central compartments by means of cationic membranes (2) and the central compartments are separated from one another by means of an anionic membrane (1); or, alternatively,ii) a module formed by an array of cells of 4 compartments separated from one another by alternating anionic membranes and cationic membranes.By means of this process, the simultaneous presence of the isolated free acids and their salts in the same compartment is prevented, which increases their purity. A large number of acids and amino acids can be isolated and purified. In a preferred embodiment, the purification and isolation of IDA is described.

Abstract: Improvements to a method for preparing N-phosphonomethylglycyne by oxidation of N-phosphonomethyliminodiacetic acid. N-phosphonomethylglycine may be obtained by oxidation of N-phosphonomethyliminodiacetic acid with O.sub.2 or with an oxygen-containing gas, in the presence of a noble metal catalyst on activated carbon. To avoid the catalyst losses, the improvements of the invention consist in a pressure scavaging with N.sub.2, after completion of the oxidation reaction. Owing to such treatment, the catalyst losses are reduced from 30% to 1%, making the processing economically viable on a large industrial scale. The recovered catalyst holds its catalytic activity and may be reused at least 20 consecutive times. N-phosphonomethylglycine is a herbicide of extended application.