- Education and Science
Crude Oil, The sticky black stuff
A chemical transformation of sediments that contain plankton and faeces.
In a nutshell that's exactly what it is, not very glamorous granted, but the importance of this mainly carbon, hydrogen substance is critical for modern day living.
Crude oil as a whole is not very useful, it needs to be put through a process called distillation to separate it in to its useful fractions
Now when crude oil is heated slowy, the different fractions within it will all boil at a certain temperature. As these fractions condense the pure liquid of these fractions will remain.
Now if the rise of temperature is controlled slowly these fractions can be extracted at certain temperatures.
Collectively the majority of products from crude oil comes in the form of hydrocarbons, these are compounds made up of carbon, hydrogen chains.
These hydrocarbons can then further be split into 2 groups, Alkanes and aromatics. Alkanes consist of single C-C and C-H bonds, these can also be split into 3 categories.
- Linear-chain alkanes
- Branched-chain alkanes
How far can you go?
Now with regards to linear-chains, very far! These single bonded carbon hydrogen chains can be as small as methane which has a molecular formula CH4, this compound is simply a carbon atom surrounded by 4 hydrogen atoms.
The other end of the scale for example, Octane which is a compound with a molecular formula of C8H18 . This comprises of a chain of 8 carbon atoms with 18 of its remaining bonds occupied by a hydrogen atom.
The imposter isomers
These imposters are very similar at a molecular level sharing the same formula, but when you start to look at it at a structural level the differences start to mount up.
As it shows in the diagram both of these butane compounds share the same molecular formula, but the structure is very different, the bottom butane isomer is a branched-chained alkane.
One of the carbon atoms splits away from the linear chain using a process called hydrocracking. This leads to a very important difference, there boiling temperatures.
The greek wheel
As the name and diagram suggest this compound comprises of a ring of carbon atoms each bonded with 2 carbon and 2 hydrogen atoms.
The other guy
The other type of hydrocarbon. this ring which looks similar to the cycloalkane is very different at a closer look. The ring (benzene ring) consists of 6 carbon atoms with its valency filled, more importantly every other carbon-carbon bond is a double bond, which means the electrons are being shared.