H Acid Free Acid (4-Amino-5-hydroxy-2,7-naphthalenedisulfonic acid) from China
The free acid form of H acid is specifically enumerated in HTS 2922.21.1000 alongside its salts. Less common than salt forms but used where specific pH control needed in dye coupling. Highly water-soluble despite free sulfonic groups.
Duty Rate — China → United States
43.3%
Rate breakdown
9903.05.3112.5%Except for products described in headings 9903.05.85–9903.05.92, articles the product of China, as provided for in U.S. note 52 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
• Neutralization equivalence point titration confirms free acid content
• Stronger corrosivity requires UN 3265 class 8 designation
• Specialized ventilation for dust exposure during unloading