4,4'-Diamino-3-biphenylsulfonic Acid (3-Benzidinesulfonic Acid) from Canada
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 — Canada → United States
15.8%
Rate breakdown
9903.05.2910%Section 301 (forced labor) — additional 10% ad valorem on products of Canada
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