Isobutene (2-Methylpropene)
Isobutene, or 2-methylpropene (CH2=C(CH3)2), is a branched butene isomer classified under HTS 2901.23.00.00 as an acyclic unsaturated hydrocarbon. Primary use is in manufacturing methyl tert-butyl ether (MTBE) and polyisobutylene.
Import Duty Rates by Country of Origin
Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If reacted to form tert-butyl derivatives
Ether or alcohol derivatives move to oxygen-function compounds later in Chapter 29.
If when used as additive in fuels
Fuel additives classified as anti-knock preparations rather than pure hydrocarbons.
Not sure which classification is right?
The Tariff Assistant works through the GRI rules on your specific product to reach the right HTS code — and can price the duty on it in the same conversation.
Import Tips & Compliance
• Include polymerization inhibitor specification to maintain classification as pure compound
• Comply with EPA VOC emission regulations for import documentation
• Separate from butadiene mixtures to avoid 2901.29 classification
Related Products under HTS 2901.23.00.00
1-Butene (But-1-ene)
1-Butene is a colorless, flammable acyclic unsaturated hydrocarbon with the formula CH2=CH-CH2-CH3, classified under HTS 2901.23.00.00 as a pure isomer of butene. It serves as a key monomer in producing linear low-density polyethylene (LLDPE) and other polymers.
cis-2-Butene
cis-2-Butene is the cis isomer of 2-butene, an acyclic alkene with formula CH3-CH=CH-CH3, falling under HTS 2901.23.00.00 for butene isomers. It is used in organic synthesis and as a research chemical.
trans-2-Butene
trans-2-Butene, the trans stereoisomer of 2-butene (CH3-CH=CH-CH3), is a separate chemically defined compound under HTS 2901.23.00.00. Commonly used in petrochemical research and isomerization studies.
1,3-Butadiene (refined isomer)
While primarily under 2901.24, highly purified 1,3-butadiene can be considered a butene-related diene isomer under HTS 2901.23.00.00 when specified as such. Used exclusively for synthetic rubber (SBR) production.
2-Butene Industrial Grade
Industrial 2-butene (mixed cis/trans isomers) is a chemically defined butene mixture under HTS 2901.23.00.00, used in solvent production and alkylation processes.
Butene-1 Polymerization Grade
High-purity butene-1 (>99.5%) specifically for LLDPE copolymer production, classified as pure butene isomer under HTS 2901.23.00.00.