METHOD AND DEVICE FOR MAKING ANILINE-FREE LEUCOINDIGO SALT SOLUTIONS

摘要

Method of making an aqueous aniline-free or aniline-free and N-methylaniline-free leucoindigo solution from an aqueous leucoindigo solution comprising aniline or aniline and N-methylaniline, the concentration of aniline or aniline and N-methylaniline being determined according to ISO 14362-1:2017(E), wherein said leucoindigo is in the form of an alkali metal salt, the method comprising at least steps (A) to (C):(A) providing a liquid stream comprising said aqueous leucoindigo solution comprising said amine(s);(B) providing a purification stream;(C) bringing into contact said liquid stream with said purification stream.