Neville-Winter Acid (1-Naphthylamine-5-sulfonic Acid) from Canada
Neville-Winter acid is an aminohydroxynaphthalenesulfonic acid used in acid dye manufacturing, subject to HTS 2922.21.4000 quotas under U.S. note 3 to section VI. Its structure with amino group ortho/para to sulfonic acid enables diazotization for azo coupling. Classification adheres to chapter priority for oxygen-function amino-naphthols.
Duty Rate — Canada → United States
16.5%
Rate breakdown
9903.05.2910%Except for products described in headings 9903.05.85–9903.05.93, articles the product of Canada, as provided for in U.S. note 52 to this subchapter
Import Tips
• Use HTS statistical annotations to track quota consumption and avoid over-import penalties
• Label containers with full IUPAC name and CAS (84-86-6) for rapid customs verification
• Test for impurities that could disqualify 'chemically defined' status per chapter note (a)