2922.21.25.00 - 1-Amino-8-hydroxy-4,6-naphthalenedisulfonic acid, monosodium salt

This category encompasses specific salts derived from aminohydroxynaphthalenesulfonic acids. These are organic compounds characterized by the presence of an amino group, a hydroxyl group, and one or more sulfonic acid groups attached to a naphthalene ring system. The salts, in this instance, are typically monosodium salts, indicating the replacement of one acidic proton with a sodium ion. These compounds often function as intermediates in the synthesis of dyes and pigments due to their chromophoric properties and ability to form stable complexes.

The distinction between this specific classification (2922.21.25.00) and its sibling category (2922.21.10.00) lies in the precise chemical structure and the resulting nomenclature of the included substances. While the sibling category lists several specific aminohydroxynaphthalenesulfonic acids and their salts by name, the present category serves as a residual or "Other" classification for any salts of aminohydroxynaphthalenesulfonic acids not explicitly enumerated in the preceding sibling. This ensures comprehensive coverage for such compounds within the tariff system.

As this node represents a leaf within the HTS structure, there are no further subcategories. Classification at this level is determined by the specific chemical identity of the substance being imported or exported, with particular attention paid to whether it is a monosodium salt of an aminohydroxynaphthalenesulfonic acid that is not otherwise specifically named in the preceding provision. The precise chemical name and salt form are critical for accurate classification.