3,6-Endoxo-1,2,3,6-tetrahydrophthalic anhydride from Mexico
Bicyclic cyclenic anhydride featuring oxygen-bridged norbornene structure with fused phthalic anhydride. Covered by HTS 2917.20.00.00 as cyclenic polycarboxylic acid derivative. Key monomer for high-temperature resistant polymers.
Duty Rate — Mexico → United States
14.2%
Rate breakdown
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
• Distinguish exo/endo isomers via NMR; both cyclenic but different reactivity profiles
• Provide Diels-Alder reaction synthesis documentation confirming structure
• Monitor double bond content as full hydrogenation changes to hexahydro version