Abstract:

The synthesis of organic dye Indigo followed by the application on the coloration of different fiber structures is introduced, as an undergraduate organic experiment widely employed overseas. Three confusing but important questions related to the synthesis procedure are also discussed, which are normally not mentioned in foreign textbooks: the synthetic mechanism for Indigo, the principle of Indigo coloration, and the process design of Indigo dyeing. The exquisitely designed procedure and practical achievement of this experiment are both worth applying to the domestic undergraduate experiments.

Key words: Indigo, Leucoindigo/Indigo white, Organic dye, Fiber, Undergraduate experiment