HS code · 6-digit subheading
HS Code 2901.23 – Acyclic hydrocarbons; unsaturated, butene (butylene) and isomers thereof
HS code 2901.23 is the 6-digit subheading for acyclic hydrocarbons, unsaturated, butene (butylene) and isomers thereof. It is used for 1-Butene, isobutylene, cis-2-Butene, trans-2-Butene and butene-1.
What HS 2901.23 covers
This category covers butene and its various isomers, such as 1-butene, 2-butene (cis and trans), and isobutylene. These unsaturated acyclic hydrocarbons are vital intermediates in the production of a wide range of chemicals and polymers. They are primarily used as co-monomers in polyethylene production, for manufacturing synthetic rubber (e.g., butyl rubber), and in the synthesis of fuel additives and specialty chemicals. International trade involves chemical companies and refiners, with major exporters often being countries with large petrochemical complexes or advanced refining capabilities, such as the United States, Saudi Arabia, and the Netherlands. Key importers include industrial nations like China, Germany, and Japan, which have significant downstream manufacturing industries. Transport typically involves specialized tankers or rail cars for liquefied gases. Market prices are influenced by crude oil and natural gas prices, as well as demand from the automotive and plastics sectors.
- Covers
- 1-Butene
- Isobutylene
- Cis-2-Butene
- Trans-2-Butene
- Butene-1
- Isobutene
- Mixed Butenes
- Examples
- ExxonMobil Chemical (producer of isobutylene)
- LyondellBasell (producer of 1-butene)
- SABIC (producer)
- INEOS (producer)
- BASF (producer)
Codes often confused with 2901.23
Common mistake. Can be confused with other C4 hydrocarbons like 290124 (butadiene) or even 290110 (butane) if the unsaturation is overlooked. The presence of a double bond and the specific C4 structure are key.
Top exporters and importers of HS code 290123, 2025
In 2025, the largest exporter of HS code 290123 in UN Comtrade data was the United States, with 31% of world exports; the largest importer in UN Comtrade data was Canada, with 34% of world imports. Countries that did not report 2025 data are estimated from partner records, which can understate them.
Top exporters 2025 · share of world exports
- 1 United States $198M 31% of world exports
- 2 Belgium $183M 29% of world exports
- 3 South Korea $71M 11% of world exports
World total: $640M Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 Canada $192M 34% of world imports
- 2 Germany $52M 9.3% of world imports
- 3 Thailand $43M 7.7% of world imports
World total: $558M 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 2901.23
Brazil does not split HS 2901.23: its NCM code is 2901.23.00.
All Brazil NCM codes in heading 29.01 →
Source: Siscomex NCM table, updated Oct 2026. The Portuguese text is official; the English is our translation.
Questions about HS 2901.23
What is HS code 290123?
HS code 290123 is a 6-digit subheading in the Harmonized System that covers: Acyclic hydrocarbons; unsaturated, butene (butylene) and isomers thereof. This category covers butene and its various isomers, such as 1-butene, 2-butene (cis and trans), and isobutylene. These unsaturated acyclic hydrocarbons are vital intermediates in the production of a wide range of chemicals and polymers. They are primarily used as co-monomers in polyethylene production, for manufacturing synthetic rubber (e.g., butyl rubber), and in the synthesis of fuel additives and specialty chemicals. International trade involves chemical companies and refiners, with major exporters often being countries with large petrochemical complexes or advanced refining capabilities, such as the United States, Saudi Arabia, and the Netherlands. Key importers include industrial nations like China, Germany, and Japan, which have significant downstream manufacturing industries. Transport typically involves specialized tankers or rail cars for liquefied gases. Market prices are influenced by crude oil and natural gas prices, as well as demand from the automotive and plastics sectors.
What products fall under HS code 290123?
1-Butene, Isobutylene, Cis-2-Butene, Trans-2-Butene, Butene-1, Isobutene, Mixed Butenes
What are common misclassifications for HS code 290123?
Can be confused with other C4 hydrocarbons like 290124 (butadiene) or even 290110 (butane) if the unsaturation is overlooked. The presence of a double bond and the specific C4 structure are key.
Which countries are the top exporters of goods under HS code 290123?
In 2025, the top exporters of HS code 290123 in UN Comtrade data were the United States ($198M, 31% of world exports), Belgium ($183M) and South Korea ($71M). World exports came to about $640M, 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 goods under HS code 290123?
In 2025, the top importers of HS code 290123 in UN Comtrade data were Canada ($192M, 34% of world imports), Germany ($52M) and Thailand ($43M). World imports came to about $558M, 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.
How is HS code 290123 structured?
HS code 290123 is a 6-digit subheading under the Harmonized System. The first 2 digits (29) identify the chapter, digits 3-4 (01) identify the heading, and digits 5-6 (23) specify the subheading. This code is standardized globally by the World Customs Organization.
What is the Brazil NCM code for HS code 290123?
In Brazil, HS code 290123 is NCM 2901.23.00. The last two digits are 00 because Brazil does not split this HS code further.