2918.99 - Other:

This HTS category, HTS 2918.99, encompasses carboxylic acids with an additional oxygen function, along with their anhydrides, halides, peroxides, and peroxyacids, and their halogenated, sulfonated, nitrated, or nitrosated derivatives, that do not fall into any more specific subheadings. The "Other" designation signifies that these compounds do not fit into the narrowly defined categories within heading 2918, such as those with a single halogen atom or the specific compound 2,4,5-T.

To differentiate from its sibling, HTS 2918.91.00.00, this category excludes the herbicide 2,4,5-T (2,4,5-trichlorophenoxyacetic acid), its salts, and its esters. Therefore, any carboxylic acid derivative with an additional oxygen function that is not 2,4,5-T and does not fit into other more specific subheadings would be classified here.

This category further subdivides based on the aromatic nature of the compounds. The presence of an aromatic ring structure in the molecule will lead to classification under the "Aromatic" subdivision. Alternatively, if the compound does not possess an aromatic structure, it will be classified under the "Other" subheading (2918.99.50.00), which serves as the residual category for non-aromatic carboxylic acid derivatives with additional oxygen functions not otherwise specified.