9.2 - Production of Materials1. Fossil fuels provide both energy and raw materials such as ethylene, for the production of other substances1.1.construct word and balanced formulae equations of chemical reactions as they are encountered1.2.identify the industrial source of ethylene from the cracking of some of the fractions from the refining of petroleumSteam (thermal) cracking:C2H6 C2H4 + H2Ã¢ÂÂH = +138kJ/moleC C C C + H2C3H8 C2H4 + CH4Ã¢ÂÂH = +87kJ/moleC C C C C + CEthane and propane are converted into ethene by heating them in a furnace with steam at a temperature of around 700-900ÃÂºC. The larger molecules are converted into the small molecules that are being formed. Energy is absorbed when breaking bonds and energy is released when bonds are formed.
C16H34 C3H6 + C2H4 + C11H24With steam cracking, it is difficult to control the size of monomers.
Catalytic cracking:Decane octane + etheneC10H22 C8H18 + C2H4With catalytic cracking, they are able to control the size of monomers.
It is also possible to carry out the reaction at a much lower temperature. The catalyst is a heterogeneous catalyst. The catalyst and the reactant are not in the same phase (solid, liquid or gas). For example, zeolite - a crystalline substance consisting of aluminium, silicon and oxygen. It is a 3-D structure consisting of many channels or pores into which the long chain molecules are absorbed and broken into smaller chain molecules.
1.3.identify that ethylene, because of the high reactivity of its double bond, is readily transformed into many useful productsAlkanes are very un-reactive. They are not as reactive as the alkenes. Alkanes are saturate hydrocarbons. They undergo substitution reactions.
CH4 + Cl2 chloromethane + hydrogen chlorideC + Cl2 C + HClChloromethane + Cl2 dichloromethane + hydrogen chlorideC + Cl2 C + HCldichloromethane + Cl2 trichloromethane + hydrogen chlorideC +...