1-Naphthylamine-4,8-disulfonic Acid (Casella's Acid) from Japan
Casella's acid features dual sulfonic groups on the 1-naphthylamine backbone, used in direct dyes. While not explicitly named, its structural similarity to listed 2921.45.25.00 compounds and retention of primary amine function justifies inclusion. Chapter 29's last-in-order rule prioritizes amine over sulfonated classifications.
Duty Rate — Japan → United States
10%
Rate breakdown
9903.03.0110%Except for products described in headings 9903.03.02–9903.03.11, articles the product of any country, as provided for in subdivision (aa) of U.S. note 2 to this subchapter
Import Tips
• Document sulfonic group count and positions via MS/NMR for classification support
• Use low-temperature storage (<25°C) and declare stability data
• Separate from mono-sulfonic isomers to avoid mixture designation confusion