Organic chemistry

• Addition polymerisation


  The reaction in which many small molecule monomers bone together to form a long chain polymer
• Addition reaction


  A reaction in which at least two molecules combine together to form larger molecule
• Alcohols


  Organic compounds containing the functional group-OH. The first four members of a homologous series of alcohols are methanol, ethanol, propanol and butanol. Alcohols can be oxidised to carboxylic acids
• Alkanes


  The most common hydrocarbon found in crude oil. The first four alkanes are methane, ethane, propane and butane. They have the general formula CH and can undergo substitution reactions with chlorine
• Alkenes


  Hydrocarbons with a double bond between two of the carbon atoms in their chain, causing them to be unsaturated. They have the general formula C,H and react to produce polymers in addition polymerisation reactions. The first three alkenes are ethene, propene and butene
• Biodegradable


  Able to be broken down by living organisms
• Carboxylic acids


  Organic compounds containing the functional group-COOH. The first four members of a homologous series of carboxylic acids are methanoic acid, ethanoic acid, propanoic acid and butanoic acid. Carboxylic acids are weak acids and can be formed by the oxidation of alcohols
• Chromatography


  A process used to separate substances in a mixture. Separation of the substance depends on distribution between a mobile phase and a stationary phase. Chromatography is used to identify the products of hydrolysis of carbohydrates and proteins
• Complex carbohydrates


  A large number of sugar units joined together in long chains by condensation polymerisation
• Condensation polymerisation


  1. Monomers join together and lose small molecules, such as water

  2. Involves monomers with two functional groups
• Cracking


  1. Breaking down larger hydrocarbons to produce smaller more useful molecules

  2. Can be done by catalytic cracking or steam cracking
• Crude oil (petroleum)


  • A finite resource found in rocks
  • Remains of an ancient biomass consisting mainly of plankton that was buried in mud
  • Most of the compounds are hydrocarbons which can be separated by fractional distillation
• Ester


  • The product of a condensation reaction between a carboxylic acid and an alcohol in the presence of an acid catalyst
  • Example: ethanol + ethanoic acid - ethyl ethanoate
• Fermentation


  1. A chemical process by which molecules such as glucose are broken down anaerobically

  2. Ethanol is produced when sugar solutions are fermented using yeast
• Fractional distillation


  1. A process used to separate a mixture of liquids, in particular to separate crude oil

  2. The liquids have different boiling points so can be separated into different fractions within a fractionating column
• Functional group


  • The group of atoms responsible for how a particular compound reacts
  • All compounds in the same homologous series have the same functional group
• General formula


  • A chemical formula which applies to a class of compounds, representing the composition of the atoms present in the compound
  • Eg. Alkanes have the general formula CnH2n+2 where n is the number of carbon atoms in the molecule
• Homologous series


  A series of compounds with the same functional group and similar chemical properties
• Hydrocarbons


  Molecules that are made up of hydrogen and carbon atoms only
• Hydrolysis


  1. The breakdown of a compound by the reaction with water

  2. Proteins can be hydrolysed to amino acids and carbohydrates can be hydrolysed to simple sugars
• Molecular formula


  The actual ratio of atoms of each element present in a compound
• Monomer


  Small short chain molecules which can join together to form a long chain polymer
• Polyamide


  • A category of polymers which contain the amide functional group in their main chain
  • Formed by a condensation reaction between a diamine and a dicarboxylic acid
• Polyester


  A category of polymers which contain the ester functional group in their main chain. Formed by a condensation reaction between a diol and a dicarboxylic acid.
• Polymer


  Large long-chain molecule made up of lots of small monomers joined together by covalent bonds.
• Proteins


  Constituents of food. Polymers made up of amino acid molecules with amide linkages. Proteins can be hydrolysed to amino acids.
• Saturated hydrocarbon


  A hydrocarbon compound containing only single bonds between carbon atoms. Alkanes are saturated compounds.
• Structural formula


  A formula which shows the arrangement of atoms in the molecule of a compound but does not show all the bonds between them. E.g. CH,CH,COCH,
• Structural isomerism


  A type of isomerism which occurs when compounds have the same molecular formula but a different structural formula.
• Unsaturated hydrocarbon


  A compound that contains double or triple carbon bonds so that it does not contain the maximum number of hydrogen atoms. Alkenes are unsaturated compounds.
• Weak acid


  A weak acid is only partially lonised in an aqueous solution. This means only a small number of the H+ ions are released. Carboxylic acids are examples of weak acids.
• What is a common example of a condensation reaction between a carboxylic acid and an alcohol?

  Ethanol + ethanoic acid -> ethyl ethanoate
• What is the formula for alkenes?

  CnH2n
• What is the formula for alkanes?

  CnH2n+2
• What is the formula for alcohols?

  CnH2n+1OH
• What is the formula for carboxylic acids?

  CnH2n+1COOH
• Manufacture of ethanol by fermentation

  1. Fermentation of glucose

  2. Conditions: temperature of about 30°C, anaerobic conditions (no oxygen) and using the enzymes in yeast

  3. Equation: glucose -> ethanol + carbon dioxide
• Manufacture of ethanol by catalytic addition of steam to ethene


  1. Reacting ethene with steam

  2. Conditions: phosphoric acid catalyst, temperature of about 300°C and a pressure of about 60-70 atm

  3. Equation: ethene + steam -> ethanol
• Fermentation


  • Renewable raw materials
  • Warm, normal pressure (inexpensive)
  • Little energy needed
• Fermentation


  • Batch process (stop-start)
  • A lot of workers needed
  • Slow
  • Impure-needs treatment