2-Butyne

2-Butyne

3D model of 2-Butyne

2-Butyne, also known as dimethylacetylene, is an alkyne with the chemical formula $\mathrm{H}{\phantom{A}}_3\mathrm{C}-\mathrm{C}\equiv \mathrm{C}-\mathrm{C}\mathrm{H}{\phantom{A}}_3$. It is a member of the butyne family, which consists of alkynes with four carbon atoms and a triple bond between two of them.

Structure and Properties

2-Butyne is a symmetrical alkyne, meaning it has a triple bond between the second and third carbon atoms in its carbon chain. The molecule is linear around the triple bond, with a bond angle of approximately 180 degrees. The presence of the triple bond gives 2-butyne its characteristic properties, such as a higher boiling point compared to its alkene and alkane counterparts.

Synthesis

2-Butyne can be synthesized through various methods, including the dehydrohalogenation of 2,3-dibromobutane or by the reaction of acetylene with methyl iodide in the presence of a strong base. These methods involve the removal of halogen atoms or the addition of methyl groups to form the triple bond characteristic of alkynes.

Reactions

As an alkyne, 2-butyne undergoes typical reactions associated with triple bonds. These include:

• Hydrogenation: 2-Butyne can be hydrogenated to form butane or 2-butene, depending on the conditions and catalysts used.
• Halogenation: It reacts with halogens to form dihaloalkanes.
• Hydration: In the presence of acid and mercury(II) salts, 2-butyne can be hydrated to form ketones.

Uses

2-Butyne is used in organic synthesis as a building block for more complex molecules. It serves as a precursor in the synthesis of pharmaceuticals, agrochemicals, and other industrial chemicals. Its reactivity makes it a valuable intermediate in various chemical reactions.

Safety

2-Butyne is a flammable liquid and should be handled with care. It can form explosive mixtures with air and should be stored in a cool, well-ventilated area away from sources of ignition.

Related Pages

• Alkyne
• Butyne
• Hydrogenation
• Organic synthesis