4,4'-Diamino-3-biphenylsulfonic Acid (3-Benzidinesulfonic Acid) from Mexico
A sulfonated aromatic polyamine used as a dye intermediate, specifically listed under HTS 2921.59.0800. It features two amine groups and a sulfonic acid function on a biphenyl structure. Classified here as it qualifies as a derivative of aromatic polyamines.
Duty Rate — Mexico → United States
15.8%
Rate breakdown
9903.05.5510%Except for products described in headings 9903.05.85–9903.05.92 and 9903.05.94, articles the product of Mexico, as provided for in U.S. note 52 to this subchapter
Import Tips
• Confirm sulfonic acid content doesn't trigger organo-sulfur exclusion (note to 2930); remains in 2921 as sulfonated derivative
• Require EPA TSCA certification; sulfonic acids often regulated for wastewater discharge
• Label with GHS pictograms for corrosivity due to sulfonic acid group