3,6-Endoxo-1,2,3,6-tetrahydrophthalic anhydride from Japan
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 — Japan → United States
12.5%
Rate breakdown
9903.05.4912.5%Section 301 (forced labor) — Japan (col1 rate < 12.5 percent): MFN < 12.5% → total duty capped at 12.5%
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