2931.43.00.00 - Diethyl ethylphosphonate

This HTS category, specifically 2931.43.00.00, covers Diethyl ethylphosphonate, an organic compound featuring both carbon and phosphorus atoms. It falls under the broader classification of "Other organo-inorganic compounds" and more specifically within the "Non-halogenated organo-phosphorous derivatives" sub-group. This means the compound contains phosphorus bonded to carbon, and it does not include halogen atoms (like chlorine, bromine, or fluorine) directly attached to the phosphorus or carbon backbone in a way that would alter its fundamental organophosphorous nature.

Diethyl ethylphosphonate is distinguished from its sibling categories by the specific alkyl groups attached to the phosphonate moiety. For example, while 2931.41.00.00 and 2931.42.00.00 represent dimethyl phosphonates with methyl or propyl substituents respectively, this entry is characterized by the presence of an ethyl group directly bonded to the phosphorus atom. Similarly, it differs from methylphosphonic acid (2931.44.00.00) and its salts by the presence of two ethyl groups in ester linkage with the phosphonate group, rather than a free acid or salt form.

As this is a leaf node within the HTS, there are no further subcategories. Therefore, classification within 2931.43.00.00 relies on the precise identification of Diethyl ethylphosphonate itself. Its primary uses often lie as a flame retardant, a plasticizer, or an intermediate in the synthesis of other chemicals. Customs officers will verify classification based on the chemical structure and purity, ensuring it precisely matches the definition of Diethyl ethylphosphonate and does not exhibit characteristics that would place it in a different organo-phosphorous derivative category.