An aliphatic hydrocarbon is composed of hydrogen and carbon and has no aromaticity.
The adjective aliphatic is used in the field of chemistry to describe those organic compounds that have an open chain as the structure of their molecules. In this way, it is possible to speak of different aliphatic type compounds.
Aliphatic hydrocarbon is the organic compound that is formed with hydrogen and carbon and that lacks aromaticity, a chemical property linked to the behavior of the electrons that are in the double bonds. These electrons, since they can move freely between the different bonds, both single and double, give a degree of stability to the molecule that would not be possible to achieve if they remained fixed in the bond.
Graphic representation and related concepts
When designing a graphic representation of the molecule taking into account aromaticity, the double bonds in one of the configurations must be drawn and related to the others through arrows, to express the other opportunities that electrons have to form new ones. bonds around the aromatic ring . An example of this behavior can be seen in benzene, whose molecule has more than one resonance state and its double bonds are represented alternating with the single ones.
There are many concepts related to the term aliphatic ; Such is the case of alkanes , hydrocarbons that exclusively contain hydrogen and carbon atoms . They are also known as saturated hydrocarbons , since they do not have double or triple bonds, which is why their carbons present a rearrangement of their electrons called hybridization . On the other hand, they do not have functional groups either.
Acetylene is an acyclic aliphatic hydrocarbon.
Aliphatic hydrocarbons
These aliphatic hydrocarbons can be cyclic or acyclic . In the case of cyclic aliphatic hydrocarbons , their aliphatic chain manages to close and forms a ring. A cycloalkane (or cyclic alkane ), therefore, is a saturated hydrocarbon composed only of carbon atoms that are joined together through single bonds that take on a ring shape. The generic formula of cyclic alkanes is CnH2nl
Acyclic aliphatic hydrocarbons have a linear hydrocarbon group. The simplest of these organic compounds are the aliphatic alkanes , with a branched or linear chain and no functional groups .
Alkanes of this type
The reactivity of aliphatic alkanes is very small in contrast to that of other organic compounds. All its links are of the sigma type , that is, simple; They are covalent and have a single pair of electrons in an s orbital, and therefore in their structure you can see a series of lines that represent the covalent bonds through which each bonded atom shares a pair of electrons with the others.
An example of an aliphatic alkane is propane , a gas derived from petroleum that has three carbon atoms. Its chemical formula is C3H8 : through industrial processes that allow gas to be liquefied, propane is used as fuel, often combined with butane .
Alkenes and alkynes, other aliphatic hydrocarbons
On the other hand we have the following two concepts:
* alkenes , unsaturated hydrocarbons that have one or more carbon-carbon bonds in their molecule . Alkenes can be understood as alkanes that have lost two hydrogen atoms, which produces a double-type bond between two carbons. In a similar way to what happens with alkanes, cyclic alkenes are called cycloalkenes ;
* alkynes , aliphatic hydrocarbons that have at least two pi and one sigma bonds that occur between two carbon atoms.
It should be noted that alkenes (such as ethylene ) and alkynes (such as acetylene ) are also acyclic aliphatic hydrocarbons. Ethylene is found naturally in plants, although it is usually obtained from hydrocarbons. The same happens with acetylene, collected from oil or natural gas through different industrial procedures.