2917.39.04.00 - 1,2,4-Benzenetricarboxylic acid, 1,2-dianhydride (Trimellitic anhydride); Phthalic acid; and 4-Sulfo-1,8-naphthalic anhydride

This HTS category, specifically 2917.39.04.00, encompasses certain aromatic polycarboxylic acids and their anhydrides that do not fall under more specific subheadings within the "Other" classification. The primary substances covered are 1,2,4-Benzenetricarboxylic acid, 1,2-dianhydride (commonly known as trimellitic anhydride), phthalic acid, and 4-Sulfo-1,8-naphthalic anhydride. These compounds are characterized by the presence of multiple carboxyl groups attached to an aromatic ring system, or their corresponding anhydride forms, and in some cases, a sulfonic acid group.

Distinguishing this code from its siblings is crucial for accurate classification. For instance, while 2917.39.08.00 specifically covers "Naphthalic anhydride," this entry includes a derivative of naphthalic anhydride (4-Sulfo-1,8-naphthalic anhydride) along with other distinct aromatic polycarboxylic acids and anhydrides. Similarly, entries for specific compounds like Isophthalic acid (2917.39.15.00) or specialized anhydrides like Tetrabromophthalic anhydride (2917.39.17.00) represent more narrowly defined substances, whereas 2917.39.04.00 acts as a residual category for other aromatic polycarboxylic acids and their derivatives that don't fit into those more precise headings.

As this is a leaf node within the HTS, there are no further subcategories to introduce. Classification under 2917.39.04.00 relies on identifying the chemical composition and structure of the imported goods, ensuring they meet the criteria of aromatic polycarboxylic acids or their anhydrides and are not specifically enumerated elsewhere within Chapter 29.