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%Except for products described in headings 9903.05.85–9903.05.92, articles the product of Japan, with an ad valorem (or ad valorem equivalent) rate of duty under column 1 less than 12.5 percent, 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