Product classification

HS code for HFO-1336mzz: 2903.51

Unsaturated fluorinated derivatives of 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).

Classification of HFO-1336mzz under HS 2903.51

HFO-1336mzz, chemically known as (Z)-1,1,1,4,4,4-hexafluoro-2-butene, is classified under HS code 2903.51. This classification is based on its chemical structure as an unsaturated fluorinated derivative of an acyclic hydrocarbon. Within Chapter 29 of the Harmonized System, heading 2903 covers halogenated derivatives. The subheadings are divided based on whether the hydrocarbon chain is saturated or unsaturated. As an "olefin" (HFO), HFO-1336mzz contains a double bond, which classifies it as unsaturated. Subheading 2903.51 was specifically established in the 2022 HS updates to include a group of environmentally preferable fluorinated gases, namely HFO-1234yf, HFO-1234ze, and HFO-1336mzz. The classification logic is driven by the explicit mention of hexafluoro-2-butene in the subheading text. This substance is primarily used as a high-efficiency blowing agent for polyurethane foams and as a refrigerant with low Global Warming Potential. Accurate classification under 2903.51 is essential for distinguishing this unsaturated compound from saturated hexafluorobutanes, which would fall under different subheadings.

Covers
  • (Z)-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz-Z)
  • (E)-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz-E)
  • Hexafluorobutene isomers used as blowing agents
  • HFO-1336mzz used in chiller applications
Also under 2903.51
  • Chemours Opteon YF (HFO-1234yf)
  • Honeywell Solstice YF (HFO-1234yf)
  • Arkema Forane 1234yf
  • Honeywell Solstice ze (HFO-1234ze)

Codes often confused with 2903.51

Common mistake. HFO-1336mzz is often misclassified under HS code 2903.59, the residual category for other unsaturated fluorinated derivatives. This occurs when the specific listing in 2903.51 is not identified. It may also be confused with saturated fluorinated hydrocarbons in the 2903.4x range if the unsaturated nature of the carbon-carbon bond is not recognized by the declarant.

2903.59Unsaturated fluorinated derivatives of acyclic hydrocarbons; n.e.c. in item no. 2903.529.03Halogenated derivatives of hydrocarbons

Top exporters and importers of HS 290351 (the code used for HFO-1336mzz), 2025

In 2025, the largest exporter of HS 290351 (the code used for HFO-1336mzz) in UN Comtrade data was the United States, with 39% of world exports; the largest importer in UN Comtrade data was the Netherlands, with 29% of world imports. Mexico reports $578M of its heading 2903 imports without product detail (confidential), so it may also belong among the top importers.

Figures cover everything classified under HS 290351, not only HFO-1336mzz.

Top exporters 2025 · share of world exports

  1. 1 United States $611M
  2. 2 Netherlands $508M
  3. 3 China $295M

World total: $1.6B Reported figures on UN Comtrade ↗

Top importers 2025 · share of world imports

  1. 1 Netherlands $412M
  2. 2 Germany $123M
  3. 3 South Korea $122M

Mexico reports $578M of its heading 2903 imports without product detail (confidential), so it may also belong among the top importers.

World total: $1.4B Reported figures on UN Comtrade ↗

How these figures are built

109 countries reported 2025 trade to UN Comtrade in HS 2022, and their own totals are used. Countries that did not report are estimated from what other countries recorded trading with them. Those estimates miss trade with other non-reporting countries, so they can be low, and a non-reporting country can rank higher than shown or be missing from the list. World totals add both and leave out trade between two non-reporting countries. Figures are in current US dollars; reported imports are mostly valued CIF and exports FOB, and exports include re-exports. The UN Comtrade links show the underlying records; they can also list a few reporters left out here (regional groups and older HS editions).

Source: UN Comtrade (United Nations Statistics Division), 2025 annual data.

Brazil NCM code for HFO-1336mzz

Brazil classifies HFO-1336mzz under NCM 2903.51.00: HS 2903.51 with 00 added.

Source: Siscomex NCM table, updated Oct 2026. The Portuguese text on each NCM page is the official one.

Questions about HFO-1336mzz

What is the HS code for HFO-1336mzz?

The HS code for HFO-1336mzz is 290351 (Unsaturated fluorinated derivatives of 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)). The HS code for HFO-1336mzz is 2903.51.

How do I classify HFO-1336mzz for customs?

HFO-1336mzz is classified under HS code 290351 — Unsaturated fluorinated derivatives of 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). This is a 6-digit subheading level code.

Is HFO-1336mzz classified with other HFOs?

Yes, HFO-1336mzz is grouped together with HFO-1234yf and HFO-1234ze under the same HS code, 2903.51, as they are all specific unsaturated fluorinated derivatives.

Which countries are the top exporters of HFO-1336mzz (HS 290351)?

In 2025, the top exporters of HS 290351 (the code used for HFO-1336mzz) in UN Comtrade data were the United States ($611M, 39% of world exports), the Netherlands ($508M) and China ($295M). World exports came to about $1.6B, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.

Which countries are the top importers of HFO-1336mzz (HS 290351)?

In 2025, the top importers of HS 290351 (the code used for HFO-1336mzz) in UN Comtrade data were the Netherlands ($412M, 29% of world imports), Germany ($123M) and South Korea ($122M). World imports came to about $1.4B, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Mexico reports $578M of its heading 2903 imports without product detail (confidential), so it may also belong among the top importers.

Is the HS code for HFO-1336mzz the same in all countries?

The base HS code 290351 for HFO-1336mzz is internationally standardized for the first 6 digits across 200+ countries. Individual countries may add additional digits for national tariff lines and specific classifications.

What is the NCM code for HFO-1336mzz in Brazil?

In Brazil, HFO-1336mzz (HS 290351) is classified under NCM 2903.51.00.