Alkanes

Linear alkanes Straight-chain alkanes are sometimes indicated by the prefix "n-" (for normal) where a non-linear isomer exists.

The odd-numbered alkanes have a lower trend in melting points than even numbered alkanes.

Alkanes are separated in an oil refinery by fractional distillation and processed into many different products.

Also, alkanes are generally unreactive chemically or biologically, and do not undergo functional group interconversions cleanly.

As the boiling point of alkanes is primarily determined by weight, it should not be a surprise that the boiling point has almost a linear relationship with the size ( molecular weight ) of the molecule.

Ball-and-stick models of the two rotamers of ethane Ethane forms the simplest case for studying the conformation of alkanes, as there is only one C–C bond.

Biological occurrence Acyclic alkanes occur in nature in various ways.

Butane is the most common alkane that is put under the process of isomerization, as it makes many branched alkanes with high octane numbers.

Cycloalkanes have similar properties to alkanes but have higher boiling points.

Different alkanes are, for example, miscible in all proportions among themselves.

For simple alkanes, the method is nonselective but too inexpensive to be useful.

For this reason, alkanes are usually shown in a zigzag arrangement in diagrams or in models.

Hence, alkanes form the upper layer in an alkane–water mixture.

Hydrodeoxygenated biodiesel is produced by direct hydrogenolysis of the fat into alkanes and propane.

In general they are volatile, but less so than their parent alkanes.

In highly branched alkanes, the bond angle may differ significantly from the optimal value (109.5°) in order to allow the different groups sufficient space.

Isomerization and reformation Dragan and his colleague were the first to report about isomerization in alkanes.

It is a mixture of paraffins ( alkanes ), cycloalkanes (naphthenes), and olefins ( alkenes ), where the usage of the terms paraffin and olefin is particular to the oil industry.

Laboratory preparation There is usually little need for alkanes to be synthesized in the laboratory, since they are usually commercially available.

Molecular geometry sp 3 -hybridization in methane The molecular structure of the alkanes directly affects their physical and chemical characteristics.