METHOD OF PURIFICATION OF THE OXALIC ACID DIAMIDE

摘要

A method of removing copper from oxamide obtained through a process which involves the use of copper catalysts, by contacting it with an aqueous solution of a suitable complexing agent, which is capable of forming copper-containing water-soluble complexes and imparts to the aqueous solution a pH comprised between 2 and 8, optionally repeating the contacting step and, finally, recovering the purified oxamide by solid-liquid separation techniques. The claimed process affords oxamide containing less than 25 ppm of copper.