2921.42 - Aniline derivatives and their salts:

This HTS category, 2921.42, encompasses a broad range of aniline derivatives and their salts. These are organic compounds characterized by an amino group (-NH2) directly attached to an aromatic ring, with further substitutions on that ring or the amino group itself. This classification covers a vast array of chemical intermediates, dyes, pharmaceuticals, and other specialized chemicals used across various industrial sectors.

Category 2921.42 distinguishes itself from its siblings by its generality. For instance, 2921.41 specifically pertains to aniline and its simple salts, while 2921.43 focuses on toluidines (aniline with a methyl group) and their derivatives. Similarly, other siblings are dedicated to diphenylamine, naphthylamines, or specific amphetamine-related compounds. Category 2921.42 serves as a catch-all for aniline derivatives that do not fit into these more narrowly defined sibling headings, requiring careful examination of the specific chemical structure for accurate classification.

Within 2921.42, further subcategories exist to provide more granular classification for specific aniline derivatives. These include provisions for compounds like N,N-Dimethylaniline and N-Ethylaniline/N,N-Diethylaniline (2921.42.15.00), recognizing common substituted anilines with distinct applications. Other subcategories address halogenated or nitrated aniline derivatives, such as 2,4,5-Trichloroaniline (2921.42.16.00) and various chloro- and nitroanilines. Additionally, important sulfonic acid derivatives of aniline, like metanilic acid and sulfanilic acid, are separately enumerated. The existence of an "Other" category within this heading signifies that it also serves to capture any remaining aniline derivatives and their salts not explicitly listed in the preceding subheadings, emphasizing the importance of consulting the detailed Explanatory Notes for definitive classification.