Examples of Alkenes

Alkenes are hydrocarbons made up of at least two carbon atoms, since the double bond would occur between them; it is for this that they are also called unsaturated hydrocarbons . They are more reactive than alkanes because it is easier to break the pi π bond. The most important are ethylene CH 2 = CH 2 and propylene CH 2 = CH – CH 3 , gases that act as fuels and as chemical reagents for the production of polymers: polyethylene and polypropylene .
Ethylene and propylene are in the gaseous state and provide a sufficient amount of heat when burned. After this combustion reaction, they release carbon dioxide (CO 2 ) and water vapor (H 2 O). Ethylene, for its part, is used to accelerate the ripening process of fruits in food distributors.
Nomenclature of alkenes
Alkenes are named taking into account the one containing the double bond as the main chain. Starting from the end to which the bond is closest , the positions are counted until the C = C is identified. The position number is written , followed by the name of the hydrocarbon chain , ending with the suffix -eno .
For example:
- 1-butene: CH 2 = CH – CH 2 –CH 3
- 2-butene: CH 3 –CH = CH – CH 3
- 1-pentene: CH 2 = CH – CH 2 –CH 2 –CH 3
- 2-pentene: CH 3 –CH = CH – CH 2 –CH 3
- 3-hexene: CH 3 –CH 2 –CH = CH – CH 2 –CH 3
If the chain has two or more double bonds, the number prefix “di, tri” is added to the name of the hydrocarbon.
For example:
- 1,3-butadiene CH 2 = CH-CH = CH 2
- 1,4-pentadiene CH 2 = CH-CH 2 -CH = CH 2
- 1,5-hexadiene CH 2 = CH-CH 2 -CH 2 -CH = CH 2
- 2,4-pentadiene CH 3 -CH = CH-CH = CH 2
- 2,4-hexadiene CH 3 -CH = CH-CH = CH-CH 3
Examples of alkenes
- Ethylene CH 2 = CH 2
- Propylene CH 2 = CH – CH 3
- 1-Butene CH 2 = CH – CH 2 –CH 3
- 2-Butene CH 3 –CH = CH – CH 3
- 1-Pentene CH 2 = CH – CH 2 –CH 2 –CH 3
- 2-Pentene CH 3 –CH = CH – CH 2 –CH 3
- 1-Hexene CH 2 = CH – CH 2 –CH 2 –CH 2 –CH 3
- 2-Hexene CH 3 –CH = CH – CH 2 –CH 2 –CH 3
- 3-Hexene CH 3 –CH 2 –CH = CH – CH 2 –CH 3
- 1-Heptene CH 2 = CH – CH 2 –CH 2 –CH 2 –CH 2 –CH 3
- 2-Heptene CH 3 –CH = CH – CH 2 –CH 2 –CH 2 –CH 3
- 3-Heptene CH 3 –CH 2 –CH = CH – CH 2 –CH 2 –CH 3
- 1-Octene CH = CH – CH 2 –CH 2 –CH 2 –CH 2 –CH 2 –CH 3
- 2-Octene CH 3 –CH = CH – CH 2 –CH 2 –CH 2 –CH 2 –CH 3
- 3-Octene CH 3 –CH 2 –CH = CH – CH 2 –CH 2 –CH 2 –CH 3
- 4-Octene CH 3 –CH 2 –CH 2 –CH = CH – CH 2 –CH 2 –CH 3
- 1,3-butadiene CH 2 = CH-CH = CH 2
- 1,4-pentadiene CH 2 = CH-CH 2 -CH = CH 2
- 1,5-hexadiene CH 2 = CH-CH 2 -CH 2 -CH = CH 2
- 2,4-pentadiene CH 3 -CH = CH-CH = CH 2