2921.45.90 - Other

This HTS category, 2921.45.90, encompasses aromatic monoamines and their derivatives, specifically those that are not explicitly listed under more specific subheadings within the 2921.45 grouping. It serves as a residual classification for compounds fitting the general description of aromatic monoamines and their salts but lacking a more precise designation within this chapter. The focus is on nitrogen-containing organic compounds where the amino group (-NH2) is directly attached to an aromatic ring system, and these specific compounds do not fall into the more defined subcategories.

This "Other" subheading distinguishes itself from its sibling, 2921.45.60, by excluding products that are specifically designated as "Products described in additional U.S. note 3 to section VI." This means that while both fall under aromatic monoamines and their derivatives, 2921.45.90 is for those not covered by that particular additional U.S. note, ensuring a clear separation of classification based on specific trade or regulatory notes.

Within this category, further subclassification exists to refine the identification of specific aromatic monoamine derivatives. The subcategory 2921.45.90.10 addresses 2-Amino-1-naphthalenesulfonic acid, also known as Tobias acid, which is a distinct chemical entity with specific applications. The remaining items within this general "Other" category are then captured under 2921.45.90.90, providing a final level of residual classification for all other aromatic monoamines and their derivatives not otherwise specified.