1. Industrial Uses of Ethene<br />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.<br />Fruit:<br />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.<br />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.<br />Plastics:<br />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.<br />PVC and polystyrene:<br />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:<br />Figure 34: 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.<br />Figure 44: Polymerization of monomer styrene to form polymer polystyrene. Where n is the number of styrene molecules.<br />Table 2. <br />Vinyl ChlorideStyreneItems that the material is found in/used forShoesCredit cardsHandle bar gripsFloor tilesFood containersCD, cassette casesPlastic cupsTV cabinetsFeatures/propertiesToxicProduces HCl when burntTransparent polymerHard<br />Antifreeze:<br />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. <br />Ethanol:<br />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).<br />Figure 54: Formation of ethanol through the hydration of ethene.<br />The diagram below (figure 6) summarizes and gives an indication of the many industrial ethene made substances.<br />800100-228600<br />Figure 64: Uses of ethene/proportions of synthetic organic chemicals which are made from ethene.<br />