2-Naphthylamine-1-sulfonic Acid (Tobias Acid) from China
Tobias Acid is the 1,2-isomer used in reactive dye synthesis for cotton textiles. HTS 2921.45.90 covers it as 'other' β-Naphthylamine derivative; salts thereof. Chapter 29 notes confirm amine-function precedence over sulfonation.
Duty Rate — China → United States
44%
Rate breakdown
9903.05.3112.5%Except for products described in headings 9903.05.85–9903.05.92, articles the product of China, as provided for in U.S. note 52 to this subchapter
9903.88.0325%Except as provided in headings 9903.88.13, 9903.88.18, 9903.88.33, 9903.88.34, 9903.88.35, 9903.88.36, 9903.88.37, 9903.88.38, 9903.88.40, 9903.88.41, 9903.88.43, 9903.88.45, 9903.88.46, 9903.88.48, 9903.88.56, 9903.88.64, 9903.88.66, 9903.88.67, 9903.88.68, or 9903.88.69, articles the product of China, as provided for in U.S. note 20(e) to this subchapter and as provided for in the subheadings enumerated in U.S. note 20(f)
Import Tips
• Specify 1-sulfonic vs 6-sulfonic (Laurent's) isomer; CAS 84-89-9 critical
• Often imported as sodium salt; declare salt form explicitly
• Reactive dye manufacturers prefer >99% purity; test certificates prevent disputes