1. Organic Chemistry VCE Chemistry Unit 1: The Big Ideas of Chemistry Area of Study 2 – Materials

2. Organic chemistry is the study of carbon compounds. Carbon has the ability to bond in many different ways with other atoms (C, H, N, O, P, S) to form the millions of organic compounds. An organic family is a set of organic compounds that have very similar structures and hence similar properties. Organic Chemistry – An Introduction

3. Hydrocarbons are classified as non-polar compounds since their carbon and hydrogen atoms have similar electronegativities and molecules are symmetrical. This means that there is no permanent build-up of charge within the molecules. As a result, they are only attracted to each other by weak dispersion forces. The greater the dispersion forces between the molecules, the more energy needed to move the molecules past each other out of the solid lattice. Hence the melting point of the solid and the boiling point and viscosity of the liquid increases! Organic Chemistry – Structure and Bonding

5. A series of compounds of similar structure in which each member differs from the next by a common repeating unit. The members of the series are called homologues. All share the same general formula. Formula of a homologue differs from its neighbour by CH 2. (e.g. CH 4, C 2 H 6 etc… ) Contain the same functional group. Have similar chemical properties. Show a gradual change in physical properties as molar mass increases. Can usually be prepared by similar methods. Organic Chemistry – Homologous Series

6. AlkanesAlkenes NameFormulaNameFormula MethaneCH 4 -- EthaneC2H6C2H6 EtheneC2H4C2H4 PropaneC3H8C3H8 PropeneC3H6C3H6 ButaneC 4 H 10 ButeneC4H8C4H8 PentaneC 5 H 12 PenteneC 5 H 10 HexaneC 6 H 14 HexeneC 6 H 12 HeptaneC 7 H 16 HepteneC 7 H 14 OctaneC 8 H 18 OcteneC 8 H 16 NonaneC 9 H 20 NoneneC 9 H 18 DecaneC 10 H 22 DeceneC 10 H 20

7. The alkane family is the set of hydrocarbons in which all the C–C bonds in their molecules are single covalent bonds. This means that each carbon atom must be bonded to four atoms in order to gain a stable electron configuration. Since this is the maximum number of atoms to which a carbon atom can be bonded, alkanes are described as saturated compounds. Alkanes have the general formula C n H 2n+2 Organic Chemistry – Alkanes

8. The alkene family is the set of hydrocarbons in which two of the carbon atoms are joined by a C=C covalent bond. All other carbon atoms are joined by single covalent bonds This means that the first family member must contain two carbon atoms. Because not all of the C–C bonds are single bonds, alkenes are described as unsaturated compounds. Alkenes have the general formula C n H 2n Alkene’s also exist where there are two double bonds present – these are called diene’s Organic Chemistry – Alkenes

9. As soon as there are four carbon atoms present in an alkane molecule, there is more than one possible spatial arrangement of the atoms. Molecules that have the same net molecular formula but different structures are termed structural isomers. Different structural isomers have slightly different physical properties as their molecules will pack together differently. Structural Isomers

10. To pick if two compounds are structural isomers, draw them and name them! Same Name? Not isomers!

11. All alkanes with 4 or more carbons have structural isomers The names that arise from using this system are termed systematic names. The system is described as systematic nomenclature. Any group of atoms that hangs off the main chain is termed a side group. In alkanes, the side groups are all alkyl groups. Alkyl groups are groups of atoms that have just one less hydrogen atom than their parent alkane. Systematic Nomenclature Alkyl radicals MethylCH 3 - CH 3 EthylCH 3 - CH 2 - C 2 H 5 PropylCH 3 - CH 2 - CH 2 - C 3 H 7

12. There are a number of rules for naming hydrocarbons. 1.Determine the longest chain of carbon atoms. 2.Determine which end is nearest to a branch, a double bond or a triple bond. Multiple bonds take precedence over a branch if they are equidistant from either end of the chain. 3.Number the carbon atoms from the end chosen. 4.Name any branches first with the ending -yl (methyl, ethyl), then the longest chain, then any multiple bond. 5.When two or more branches occur on the same carbon atom, the number of the carbon atom is indicated for each branch, with the names given in alphabetical order. 6. When two or more identical branchesoccur on different carbon atoms, the prefixes di-, tri- and tetra- are used. Systematic Nomenclature

13. Systematic Nomenclature - Alkanes

14. Systematic Nomenclature - Alkenes

15. The bond, atom, or group of atoms which gives a molecule its specific properties is called its functional group. Haloalkanes (R-X, X = F, Cl, Br, I): The Halo Group CH 3 CH 2 CH 2 CH 2 Cl1-chlorobutane Alcohols (R-OH): The Hydroxyl Group CH 3 CH 2 CH 2 CH 2 OH1-butanol Carboxylic Acids (R-COOH): The Carboxyl Group CH 3 CH 2 CH 2 COOHbutanoic acid Functional Groups

16. Alkanes undergo substitution reactions. Substitution reactions occur when an atom or group of atoms replace an atom in the original molecule. E.g. Ethane reacts with chlorine in the presence of sunlight to form chloroethane. CH 3 CH 3 (g) + Cl 2 (g) (light)  HCl (g) + CH 3 CH 2 Cl (g) Reactions of Alkanes

17. Alkenes undergo addition reactions. Addition reactions occur when a group of atoms bind to an unsaturated hydrocarbon, forming a single C-C bond. In this process two reactant molecules become one. E.g. The chlorinatation of ethene to form chloroethane. CH 2 =CH 2 (g) + HCl (g)  CH 3 CH 2 Cl (g) The hydrogenation of ethene to form ethane. CH 2 =CH 2 (g) + H 2 (g)  CH 3 CH 3 (g) The reaction of ethene with steam to form ethanol CH 2 =CH 2 (g) + H 2 O(g) (cat)  CH 3 CH 2 OH(l) Reactions of Alkenes

18. Polymerisation of Alkenes Process During polymerisation, an alkene undergoes an addition reaction with itself All the atoms in the original alkenes are used to form the polymer Long hydrocarbon chains are formed ADDITION POLYMERISATION OF ETHENE The equation shows the original monomer and the repeating unit in the polymer ethene poly(ethene) MONOMER POLYMER n represents a large number

19. ETHENE EXAMPLES OF ADDITION POLYMERISATION PROPENE TETRAFLUOROETHENE CHLOROETHENE VINYL CHLORIDE POLY(ETHENE) POLY(PROPENE) POLY(CHLOROETHENE) POLYVINYLCHLORIDE (PVC) POLY(TETRAFLUOROETHENE) (PTFE) “Teflon” Polymerisation of Alkenes

20. In the past, most organic chemicals were derived from coal. Nowadays, natural gas and crude oil from petroleum provide an alternative source. The composition of petroleum varies from one oilfield or gasfield to another and is variable between adjacent wells. Crude Oil Natural GasCrude Oil Consists primarily of methaneConsists primarily of alkanes Usually contains a small percentage of ethane (<10%) A large range of alkanes is present; molecular size can range from C1 to C70, with numerous isomers present May contain smaller percentages of other alkanes such as propane, butane and pentane Contains small amounts of organic compounds which also contain sulphur, nitrogen or oxygen atoms May contain a small amount of nitrogen, carbon dioxide or hydrogen sulphide

21. Separation of the components of crude oil is accomplished by fractional distillation, in a fractionating tower. Crude oil is separated into several fractions, each containing a number of hydrocarbons which have similar boiling points. Crude oil or natural gas entering the fractionating tower is first heated to about 350 o C so that it becomes a hot mixture of vapour and liquid. On entering the tower the liquid and vapour immediately separate and the vapour rises upwards. As the mixture of the hydrocarbon gases moves up the tower there is a gradual decrease in temperature. Fractional Distillation

22. Boiling C’s per Name of Use(s) range / °C molecule fraction < 25 1 - 4 REFINERY GASLPG Camping Gas 40-100 4 - 12 GASOLINEPetrol 100-150 7 - 14 NAPHTHAPetrochemicals 150-200 11 - 15 KEROSINEAviation Fuel 220-350 15 - 19 GAS OILCentral Heating Fuel > 350 20 - 30 LUBRICATING OIL Lubrication Oil > 400 30 - 40 FUEL OILPower Station Fuel Ship Fuel > 400 40 - 50 WAX, GREASECandles Grease for bearings > 400 > 50 BITUMENRoad surfaces Roofing Fractional Distillation

23. When alkanes are subjected to high temperatures, carbon- carbon bonds can be broken, producing smaller molecules. Molecules formed include small alkanes or unsaturated molecules such as ethene, propene and butadiene. Hydrogen gas may also be produced. This decomposition by heating is called cracking. Thermal Cracking – to produce unsaturated hydrocarbons, such as ethene and propene. Catalytic Cracking – to increase the amount of lighter fractions recovered from crude oil. Thermal and Catalytic Cracking

24. Oil Refinery

25. THE ALTONA PETROCHEMICAL COMPLEX