ORGANIC CHEMISTRY
CRUDE OIL, HYDROCARBONS AND ALKANES
Crude oil: a finite resource found in rocks, remains of ancient biomass consisting mainly of
plankton that was buried in mud
o A mixture of a very large number of compounds
o It is possible to separate the substances in the mixture by methods such as
distillation
o Most of the compounds in crude oil consist of hydrocarbons
Most of these hydrocarbons are alkanes
Hydrocarbons: compounds made up of hydrogen and carbon only
o General formula: CnH2n+2
Alkanes
o Properties:
Example of a homologous series: a group of organic compounds that have
the same functional group and react in a similar way
Fully saturated hydrocarbons as all the carbon to carbon bonds are single
bonds
o First 3 alkanes: methane, ethane, propane, butane
FRACTIONAL DISTILLATION AND PETROCHEMICALS
Process:
o Crude oil is heated until it vaporises
o The vapour rises the fractioning tower and cools as it does so
o The vapour condenses at the point in the tower where the temperature falls below
their boiling point
The purpose of fractional distillation is to separate crude oil into groups of hydrocarbons
with similar boiling points, known as fractions
o The fractions with the highest boiling points condense near the bottom of the tower
where the temperature is highest
o The fractions with the lower boiling points condense at the top of the tower where
the temperature is lower
USES OF PETROCHEMICALS:
o Crude oil: fuel, feedstock to make new compounds (polymers, lubricants, solvents,
detergents)
o Bitumen (located near the bottom of the tower): road surfaces
o Heavy fuel oil: heating, lubricating
o Diesel oil: fuel for lorries
o Kerosene: fuel for aeroplanes
o Petrol (located at the top of the tower): fuel for cars
CRUDE OIL, HYDROCARBONS AND ALKANES
Crude oil: a finite resource found in rocks, remains of ancient biomass consisting mainly of
plankton that was buried in mud
o A mixture of a very large number of compounds
o It is possible to separate the substances in the mixture by methods such as
distillation
o Most of the compounds in crude oil consist of hydrocarbons
Most of these hydrocarbons are alkanes
Hydrocarbons: compounds made up of hydrogen and carbon only
o General formula: CnH2n+2
Alkanes
o Properties:
Example of a homologous series: a group of organic compounds that have
the same functional group and react in a similar way
Fully saturated hydrocarbons as all the carbon to carbon bonds are single
bonds
o First 3 alkanes: methane, ethane, propane, butane
FRACTIONAL DISTILLATION AND PETROCHEMICALS
Process:
o Crude oil is heated until it vaporises
o The vapour rises the fractioning tower and cools as it does so
o The vapour condenses at the point in the tower where the temperature falls below
their boiling point
The purpose of fractional distillation is to separate crude oil into groups of hydrocarbons
with similar boiling points, known as fractions
o The fractions with the highest boiling points condense near the bottom of the tower
where the temperature is highest
o The fractions with the lower boiling points condense at the top of the tower where
the temperature is lower
USES OF PETROCHEMICALS:
o Crude oil: fuel, feedstock to make new compounds (polymers, lubricants, solvents,
detergents)
o Bitumen (located near the bottom of the tower): road surfaces
o Heavy fuel oil: heating, lubricating
o Diesel oil: fuel for lorries
o Kerosene: fuel for aeroplanes
o Petrol (located at the top of the tower): fuel for cars
