4-Sulfo-1,8-Naphthalic Anhydride from China
4-Sulfo-1,8-naphthalic anhydride is a sulfonated aromatic polycarboxylic anhydride used in fluorescent brighteners and dye intermediates. Explicitly listed in HTS 2917.39.04.00 covering sulfonated derivatives per Chapter notes. Chemically defined compound with sulfo group directly characterized.
Duty Rate — China → United States
41.5%
Rate breakdown
9903.03.0110%Except for products described in headings 9903.03.02–9903.03.11, articles the product of any country, as provided for in subdivision (aa) of U.S. note 2 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
• Verify CAS 81-46-9 registration; confirm sulfo group content via FTIR spectroscopy
• Hazard Class 8 corrosive labeling required (UN 3261); segregation from amines mandatory
• Dye industry end-use certificates prevent reclassification as coloring matter (Chapter 32 exclusion)