4-Sulfo-1,8-Naphthalic Anhydride from China
4-Sulfo-1,8-naphthalic anhydride is a sulfonated aromatic polycarboxylic anhydride used in the production of fluorescent brighteners and dye intermediates. It is a separate chemically defined organic compound, and its sulfonation does not remove it from the scope of heading 29.17, as the derivatives are covered by the heading's text.
Duty Rate — China → Canada
0%
Import Tips
• Ensure the product is a separate chemically defined compound; if it contains impurities, they must be incidental
• Verify that the sulfonic acid group is directly attached to the aromatic ring, as this confirms classification under heading 29.17
• Keep technical data sheets to support the chemical identity if requested by the CBSA