Industrial uses of ethene

1. Industrial Uses of Ethene

Ethene has two main industrial uses. Ethene is used to accelerate the ripening of fruits and is
most commonly used on bananas and also on citrus fruits. The other use of ethene is in the
manufacture of plastics, such as packing films, wire coatings, and squeeze bottles.

Fruit:
Ethene is made from the process of cracking hydrocarbons from petroleum. Ethene can then
be used to make other raw materials like, ethanal, ethanol, and ethyl chloride. Ethene also
occurs naturally in plants and stimulates the ripening of fruits. However by keeping the fruit
in a chamber, such as a greenhouse, the amounts of ethene present in the air can be
controlled, and thus the degree of ripening of the fruit can also be controlled.
The ethene allows the fruit to mature in colour and ripen. This process takes place over a few
days, and the more ethene that is used, the faster the fruit will ripen.

Plastics:
As for the industrial use of ethene in plastics, the ethene must first undergo polymerization.
As briefly mentioned before, polymerization is the process where ethene is converted to
polyethene through an addition reaction in the presence of a catalyst. Polymerization is an
exothermic reaction as heat is given off and requires high temperatures and pressures for it to
occur. Many examples of polyethene that are commonly found in households include, milk
bottles, bins and microwave wraps.

PVC and polystyrene:
While ethene by itself is not particularly useful, it can be used to produce chemicals such as
vinyl chloride (CH2=CHCl) and styrene (CH2=CH(C6H5)) which in turn can undergo
polymerization to produce polyvinyl chloride (PVC) and polystyrene respectively.
Traditional materials like rubber, steel, ceramics and glass are often replaced with PVC as it
is a very versatile material and even simple modifications to the basic properties of the
material can lead to a range of applications and different materials formed. One property of
PVC is that it is thermoplastic and the material is usually mixed with additives which allows
flexibility and strengthens it against UV rays. PVC is widely used and can be found as
packaging and wire coatings while polystyrene is also used for packaging. The
polymerization reactions of these monomers are illustrated below in figures 3 and 4:


Figure 3
4
: Polymerization of monomer vinyl chloride to form polymer polyvinyl chloride.
Where n is the number of vinyl chloride molecules. Vinyl chloride is formed from
the reaction between the chlorine from the electrolysis of sodium chloride and
ethene.

2. Figure 4
4
: Polymerization of monomer styrene to form polymer polystyrene. Where n is the
number of styrene molecules.

Table 2.
Vinyl Chloride Styrene
Items that the
material is found
in/used for
Shoes
Credit cards
Handle bar grips
Floor tiles
Food containers
CD, cassette cases
Plastic cups
TV cabinets
Features/properties Toxic
Produces HCl when burnt
Transparent polymer
Hard


Antifreeze:
Ethylene glycol (CH2OH-CH2OH), also known as ethane-1,2-diol is a crucial component of
antifreeze and is another chemical that is produced from ethene. Ethylene glycol in its pure
form is a colourless and viscous liquid. Since the molecule has two hydroxyl groups, it is
readily soluble in water. Therefore in antifreeze solutions, ethylene glycol is mixed with
water and since aqueous solutions of ethylene glycol have higher boiling and lower freezing
temperatures than normal water and do not aid to the corrosion of iron, it is commonly used
in car radiators.




Ethanol:
One application of ethene is the production of ethanol, which is then used as a solvent in
pharmaceuticals, inks and cosmetics and as a reagent for industrial applications. The
production of ethanol occurs through the reaction between ethene and water in the presence
of phosphoric acid, the catalyst. The reaction equation is shown below (figure 5).


Figure 5
4
: Formation of ethanol through the hydration of ethene.

3. The diagram below (figure 6) summarizes and gives an indication of the many industrial
ethene made substances.





















Figure 6
4
: Uses of ethene/proportions of synthetic organic chemicals which are made from
ethene.