2933.31.00.00 - Pyridine and its salts

This HTS category, 2933.31.00.00, specifically covers pyridine and its salts. Pyridine is a basic heterocyclic organic compound with the chemical formula C₅H₅N. It serves as a fundamental building block in the synthesis of a wide range of chemicals, including pharmaceuticals, agrochemicals, and solvents. The inclusion of "its salts" signifies that any salt formed by pyridine with an acid is also classified here, provided it meets the structural requirements of pyridine as the base.

This classification is distinct from its sibling categories by its exclusive focus on pyridine and its direct salts. For instance, while 2933.32 covers piperidine and its salts, piperidine is a saturated heterocyclic compound derived from pyridine, representing a different chemical structure and thus a separate classification. Similarly, categories like 2933.33.01.00, 2933.34.00.00, and others deal with more complex heterocyclic compounds that may contain a pyridine ring but are further substituted or modified, or include fused ring systems. The key differentiator for 2933.31.00.00 is the presence of the fundamental, unfused pyridine ring as the sole defining heterocyclic feature, without additional complex functionalization or ring fusion.

As this is a leaf node within the HTS structure, there are no further subcategories. Therefore, classification within 2933.31.00.00 hinges on accurately identifying the substance as pyridine itself or a direct salt thereof, based on its chemical composition and structure. Common examples falling under this heading would include pure pyridine used as a solvent or reagent, or simple pyridine hydrochlorides and sulfates.