2921.43.90.20 - 2-Chloro-p-toluidine-5-sulfonic acid (CAS No. 88-51-7)

This HTS classification, 2921.43.90.20, specifically designates 2-Chloro-p-toluidine-5-sulfonic acid (CAS No. 88-51-7). This chemical compound is an aromatic amine derivative characterized by the presence of both a chlorine atom and a sulfonic acid group attached to a p-toluidine backbone. It falls within the broader category of toluidines and their derivatives, which are distinguished by the methyl group on the benzene ring of the aniline structure.

Within the "Other" subcategory for toluidines and their derivatives, this specific item is distinguished from its sibling category, 2921.43.90.40, which covers p-Toluidine-m-sulfonic acid (CAS No. 88-44-8). The key difference lies in the positional isomerism of the sulfonic acid group and the presence of a chlorine substituent on the aromatic ring. While both are sulfonic acid derivatives of toluidine, the specific arrangement of functional groups, namely the 2-chloro substitution and the 5-sulfonic acid position, uniquely identifies this particular compound.

As a leaf node in the HTS structure, 2921.43.90.20 represents the most granular level of classification for this specific chemical. Therefore, there are no further subcategories to introduce. Classification under this code relies on the precise chemical identity and structure of 2-Chloro-p-toluidine-5-sulfonic acid, as defined by its CAS number and systematic name.