p-Toluenesulfonic Acid (PTSA) from Mexico
p-Toluenesulfonic acid is a strong organic acid obtained by sulfonation of toluene, fitting the definition of sulfonated aromatic hydrocarbons. It qualifies for HTS 2904.99.40.00 as described in additional U.S. note 3 to section VI, used as a catalyst in esterification and polymerization. The monohydrate form is also common in imports.
Duty Rate — Mexico → United States
110%
Rate breakdown
9903.04.6094.5%Except as provided in heading 9903.04.61, patented pharmaceutical articles as provided for in subdivisions (c) and (d) of U.S. note 40 to this subchapter
9903.05.5510%Except for products described in headings 9903.05.85–9903.05.92 and 9903.05.94, articles the product of Mexico, as provided for in U.S. note 52 to this subchapter
Import Tips
• Submit certificate of analysis confirming >95% purity to meet 'separate chemically defined compound' requirement
• Declare hydration state (anhydrous vs monohydrate) accurately for correct duty assessment
• Watch for reclassification if mixed with solvents beyond transport allowances per chapter note (e)