2917.35.00.00 - Phthalic anhydride

This HTS category, 2917.35.00.00, specifically classifies phthalic anhydride. Phthalic anhydride is an organic compound that serves as a crucial intermediate in the production of various chemical products, most notably plasticizers, unsaturated polyester resins, and alkyd resins. Its structure is characterized by an anhydride group bridging two adjacent positions on an aromatic benzene ring.

Within the broader classification of aromatic polycarboxylic acids and their derivatives, phthalic anhydride stands apart from its siblings. For instance, it is distinct from the orthophthalate esters listed under 2917.32.00.00 and 2917.33.00, which are esters derived from phthalic acid, not the anhydride itself. Similarly, it differs from terephthalic acid and its derivatives (2917.36.00.00 and 2917.37.00.00), which are isomers of phthalic acid and have different chemical structures and applications.

As this node represents a leaf node within the HTS, there are no further subcategories. Classification under 2917.35.00.00 is definitive for phthalic anhydride. When classifying goods, it is essential to confirm the chemical identity of the substance and distinguish it from structurally similar compounds, particularly its esters and isomers of dicarboxylic acids, to ensure accurate tariff treatment.