Process for purifying leucoindigo salt solutions using an inert gas

Abstract

The present invention refers to a process for purifying leucoindigo salt solutions, for removal of aromatic amines, particularly aniline and N-methylaniline, comprising: adding to a purification vessel a leucoindigo salt solution containing aromatic amines, said solution in the form of a stationary mass; bubbling with a controlled flow rate an inert gas in the purification vessel, by means of a device submerged at the surface of the stationary mass; injecting with a controlled flow rate a gas purification current into the vessel, by means of a device submerged at the stationary mass; and recovering the purified solution from the vessel. It also refers to the use of inert gas in a process for purifying leucoindigo salt solutions, acting as a gas anti-foaming agent, to reduce foam and chances of product stripping during processing.

Dependencies are inferred from the claim text.