Section C: Petroleum as a Building Source In this section we study: –Common hydrocarbon “builder molecules” and –Some materials made from them

Section C.1: Creating New Options: Petrochemicals Petrochemicals – compounds produced from oil and natural gas Some petrochemicals are used directly: detergents, pesticides, pharmaceuticals & cosmetics Most are raw materials - mostly in plastics: paints, fabrics, rubber, insulation, foams, adhesives, etc. Only a few builder molecules are used to make 1000’s of new substances.

Section C.1: Creating New Options: Petrochemicals (continued) 1 key builder molecule is ethene, or ethylene H H | | C==C + H–OH  H–C–C–H | | H H H OH EtheneWater Ethanol (addition reaction) Easily reacts due to double bond

Section C.1: Creating New Options: Petrochemicals (continued) Ethene can react with itself (500-20,000 times) : H H H H H H H H H H | | | | | | | | | | n C=C  -C-C-C-C-C-C-  -(-C-C-)-n | | | | | | | | | | H H H H H H H H H H Ethene (a monomer) Growing polymer chain Polyethene (a polymer) This reaction is an addition polymer

Section C.1: Creating New Options: Petrochemicals (continued) Many polymers can be created monomers that resemble ethene: H H H H H H H H | | | | | | | | C=C  (-C-C-C-C-C-C-)n C=C  (-C-C-C-C-C-C)n | | | | | | | | H Cl H ClH ClH Cl H CN H CNH CNH CN Vinyl chloride Polyvinyl chloride Acrylonitrile Polyacrylonitrile (a monomer) (a polymer) (a monomer) (a polymer) Also, styrene and polystyrene (benzene atom)

Section C.2 – Beyond Alkanes Carbon atoms bond with 4 other atoms (alkanes/saturated), they can also bond with 3 other atoms (alkenes/unsaturated) Carbon to carbon bonding like in Ethene is a double covalent bond and better building blocks – unsaturated prefer a 4 th atom Different atoms(1) and arrangements of like atoms(2) dramatically changes the substance: 1.Oxygen, nitrogen, chlorine or sulfer 2.C 2 H 6 O (grain alcohol) & C 2 H 6 O 2 (antifreeze)

Section C.3 (lab) – The Builders Alkene names are like alkane names: ethene, propene, butene, etc. No methene as must have 2 Carbon atoms. 1-butene, double bond is between 1 st & 2 nd, 2-butene, double bond is between 2 nd & 3 rd.

Section C.4 – More Builder Molecules Two new classes of compounds (rings): –Cyclohexane for nylon: a cycloalkane, saturated –Aromatic compounds: unsaturated, benzene is simplest. No surprise – has a pleasing smell. Cyclohexane Benzene or CH 2 CH

Section C.4 – More Builder Molecules (continued) Oddly, the double bonds in benzene are not reactive. Evidence is that bonds are =, not alternating. Electrons are shared equally with all 6 carbon atoms! So… we draw benzene: Petroleum has few aromatic compounds, but many are made by cracking and fractionating. Dye and drug industries are based on aromatics

Section C.5 – Builder Molecules Containing Oxygen

Section C… More to come More to come… For more on diamonds, buckey balls, etc see: