2903.51.10.00 - 2,3,3,3-Tetrafluoropropene (HFO-1234yf),1,3,3,3-tetrafluoropropene (HFO-1234ze) and (Z)-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz)

This HTS classification, 2903.51.10.00, specifically enumerates and classifies three distinct fluorinated unsaturated acyclic hydrocarbons: 2,3,3,3-Tetrafluoropropene (HFO-1234yf), 1,3,3,3-tetrafluoropropene (HFO-1234ze), and (Z)-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz). These compounds are characterized by the presence of both carbon-carbon double bonds (unsaturation) and fluorine atoms within their acyclic hydrocarbon structures. Their primary applications include use as refrigerants, blowing agents, and propellants, often as replacements for ozone-depleting substances and high global warming potential hydrofluorocarbons (HFCs).

This category is distinguished from its sibling, 2903.59, which covers "Other" unsaturated fluorinated derivatives of acyclic hydrocarbons not specifically listed under 2903.51. Therefore, any unsaturated fluorinated acyclic hydrocarbon that does not precisely match the chemical identity of HFO-1234yf, HFO-1234ze, or HFO-1336mzz would be directed to the broader "Other" subheading. The specificity of 2903.51.10.00 ensures precise classification for these widely utilized modern fluorocarbons.

As this classification represents a leaf node in the HTS structure, there are no further subcategories. Classification at this level requires a precise identification of the imported substance as one of the three named compounds. Verification of the chemical identity through certificates of analysis or other supporting documentation is crucial for accurate customs declaration and clearance.