1-Butene vs. 2-Butene

What's the Difference?

1-Butene and 2-Butene are both isomers of butene, a hydrocarbon with four carbon atoms and a double bond. The main difference between the two isomers lies in the position of the double bond. In 1-Butene, the double bond is located between the first and second carbon atoms, while in 2-Butene, it is between the second and third carbon atoms. This difference in double bond position leads to distinct chemical properties and reactivity. Additionally, 1-Butene is more stable and less reactive than 2-Butene due to the presence of a methyl group on the second carbon atom, which provides additional steric hindrance.


Chemical FormulaC4H8C4H8
Structural FormulaCH3CH2CH=CH2CH3CH=CHCH3
Isomer TypeTerminalInternal
Double Bond PositionBetween carbon 1 and 2Between carbon 2 and 3
Boiling Point-6.3°C-6.3°C
Melting Point-185.3°C-138.9°C
Density0.62 g/cm³0.62 g/cm³
Molar Mass56.11 g/mol56.11 g/mol
OdorSweet, gasoline-likeSweet, gasoline-like

Further Detail


1-Butene and 2-Butene are both important chemical compounds belonging to the family of butenes. These compounds are classified as alkenes, which means they contain a carbon-carbon double bond. While they share some similarities, they also have distinct attributes that set them apart. In this article, we will explore the various characteristics of 1-Butene and 2-Butene, including their chemical structures, physical properties, uses, and potential hazards.

Chemical Structures

1-Butene, also known as alpha-butylene, has the chemical formula C4H8. It consists of four carbon atoms and eight hydrogen atoms, with a double bond between the first and second carbon atoms. On the other hand, 2-Butene, also called cis-butene or Z-butene, has the same chemical formula but a different structural arrangement. In 2-Butene, the double bond is between the second and third carbon atoms. This subtle difference in the placement of the double bond leads to distinct properties and reactivity.

Physical Properties

When it comes to physical properties, 1-Butene and 2-Butene exhibit some similarities but also display notable differences. Both compounds are colorless gases at room temperature and have a characteristic odor. However, 1-Butene has a boiling point of approximately -6.3°C (-21.3°F), while 2-Butene has a slightly higher boiling point of around -4.9°C (23.2°F). This difference can be attributed to the variation in molecular structure, which affects intermolecular forces and the strength of attractive interactions between molecules.

Furthermore, 1-Butene and 2-Butene have different densities. 1-Butene has a density of about 0.62 g/cm³, whereas 2-Butene has a slightly higher density of approximately 0.63 g/cm³. These variations in density and boiling point can impact their applications in different industries, such as in the production of plastics, fuels, and solvents.


Both 1-Butene and 2-Butene find applications in various industries due to their unique properties. 1-Butene is primarily used as a monomer in the production of polyethylene, a widely used plastic. It serves as a building block for the synthesis of linear low-density polyethylene (LLDPE), which is used in packaging films, pipes, and other plastic products. Additionally, 1-Butene can be used as a fuel additive to enhance the octane rating of gasoline.

On the other hand, 2-Butene has different applications. It is commonly used as a starting material in the production of butadiene, a key ingredient in the manufacturing of synthetic rubber. Butadiene is utilized in the production of tires, hoses, gaskets, and other rubber products. Furthermore, 2-Butene can be employed as a solvent in various chemical reactions and as a raw material for the synthesis of other chemicals, including pharmaceuticals and fragrances.

Potential Hazards

While 1-Butene and 2-Butene have numerous industrial applications, it is important to be aware of their potential hazards. Both compounds are flammable and can form explosive mixtures with air. They should be handled with caution and stored in appropriate containers away from ignition sources. In case of a fire involving these substances, it is crucial to use suitable extinguishing agents, such as carbon dioxide or dry chemical powder.

Moreover, prolonged exposure to high concentrations of 1-Butene or 2-Butene vapor may cause irritation to the respiratory system, eyes, and skin. Adequate ventilation and personal protective equipment should be used when working with these compounds to minimize the risk of inhalation or contact. It is also important to follow proper disposal procedures to prevent environmental contamination.


In conclusion, 1-Butene and 2-Butene are important chemical compounds with distinct attributes. While they share a similar chemical formula, their structural arrangement, physical properties, uses, and potential hazards differ. Understanding these differences is crucial for various industries that rely on these compounds for the production of plastics, rubber, solvents, and other chemicals. By considering their unique characteristics, scientists and engineers can harness the potential of 1-Butene and 2-Butene to develop innovative products and processes.

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