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%Section 301 (forced labor) — additional 10% ad valorem on products of Mexico
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