Methylphosphonic Acid Monomethyl Ester from Canada
This partial ester (CH3P(O)(OH)(OCH3)) has phosphorus bonded to one methyl group, meeting the HTS 2931.49.0055 specification precisely. The single methoxy group counts as the allowed C1 substituent. Used in specialty polymer flame retardants.
Duty Rate — Canada → United States
100%
Rate breakdown
9903.04.6096.3%Pharmaceuticals Annex IV: patented pharma articles — 100% floor rate
9903.05.900%Articles already subject to Section 232 (steel/aluminum/copper + derivatives, autos + parts, wood, medium/heavy vehicles + parts, semiconductors, patented pharma) — U.S. note 52(f)
Import Tips
• Label with exact CAS number (25989-52-0) and IUPAC name for customs verification
• Declare stabilization additives separately to avoid mixture classification issues