4,4'-Diamino-3-biphenylsulfonic Acid (3-Benzidinesulfonic Acid) from Germany
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 — Germany → United States
10%
Rate breakdown
9903.05.3910%Except for products described in headings 9903.05.85–9903.05.92 and 9903.05.97, articles the product of a member state of the European Union, with an ad valorem (or ad valorem equivalent) rate of duty under column 1 less than 10 percent, 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