... the synthesis of high a high-grade dyes, pigments intermediates 1,4,5,8-Naphthalenetetracarboxylic dianhydride is a high-grade dyes ... as polyimide resin productionAppearance Pale yellow powderPurity ≥97%Melting point≥300 1,4,5,8-naphthalenetetracarboxylic dianhydride