Colorants from naphthalene -1,4,5,8-tetracarboxylic acid

摘要

NAPHTHALENE-1,4,5,8-tetracar-boxylic acid is used in the preparation of several colorants like vat dyes, reactive dyes, pigments and others giving yellow, orange, red, brown and blue shades, Naphthalene-1,4,5,8-tetracarboxylic acid is a stable molecule. It is not attacked by warm oleum or nitric acid or bromine in concentrated sulphuric acid. On drying at above 100℃ it forms the anhydride .