20 Examples of Alkynes

The alkynes or acetylenic hydrocarbons are hydrocarbons which are characterized by the presence of a carbon-carbon triple bond. Non-cyclic alkynes respond to the molecular formula C n H2 n-2 , where n represents the number of carbon atoms. They have a degree of establishment even higher than that of alkenes . For example: ethyne, propyne, 2-butyne, 3-octyne .

Among the physical properties of alkynes, the fact that they are low polarity compounds stands out , therefore insoluble in water but quite soluble in common organic solvents such as ether, benzene or carbon tetrachloride.

The boiling and melting points of alkynes are very similar to those of alkanes or alkenes of the same carbon number. On the other hand, the effect on these physical properties of the number of carbon atoms and the presence of branches in the chain (which change in the same direction) is more noticeable. That is, the boiling and melting point increases the more carbon atoms the alkyne has.

The simplest alkyne is acetylene, followed by propylene (or propyne) and butyne, which can be 1-butyne (triple bond at the end of the molecule ) or 2-butyne (triple bond in the center of the molecule) . These three are gases; those with the highest number of carbon atoms are liquid or solid.

In a similar way to alkenes, the triple bonds that characterize alkynes give these substances great chemical reactivity and make them very prone to undergo addition reactions (of hydrogen, halogens, water, etc.) and others. However, the three bonds that join one carbon atom with another are not equivalent: one of them (which is called the sigma bond) is stronger and acts as the main responsible for the union. When an alkyne is hydrogenated, the resulting compound can become double bonds or just single bonds.

Compounds that have the triple bond at one end of the chain are called terminal alkynes . These compounds are characterized by their marked acidity, in fact, terminal alkynes are the most acidic simple hydrocarbons.

The length between carbon atoms in the bond is 1.20 pm (picometers), even less than that of alkenes (1.34 pm) and that of alkanes (1.54 pm). Single, double and triple carbon-carbon bonds can coexist in the same molecule. When this happens, the hydrocarbon is named as an alkyne and the position of the double bond is marked with the ending “ene”, inserting it where appropriate.

  • It can serve you: Alkanes

Examples of alkynes

Examples of alkynes are shown below:

  1. ethyne
  2. tip
  3. 2-butyne
  4. 2-pentine
  5. 1-butyne
  6. October 3
  7. cyclobutine
  8. tert-butyl acetylene
  9. 6,6-diethyl-4-nonino
  10. 1-ene-4-hexyne
  11. 2-nonino

 

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