Chapter 24:Alcohols and Carboxylic acids

Alchohols

• Alcohols contain the hydroxyl (-OH) functional group

• Alcohols are a homologous series of compounds that have the general formula CnH2n+1OH

• They differ by one -CH2 in the molecular formulae

• Ethanol : C2H6OH

• Methanol CH3OH

• Propanol C3H7OH

• Butanol C4H9OH

  

• There are two methods used to manufacture ethanol:

1.The hydration of ethene with steam

• [ ] Ethene is bubbled through a phosphoric acid catalyst under pressure and at a temperature of 300°C.
• [ ] Ethene + steam ➡️ethanol

2.The fermentation of glucose

• [ ] Conversion of glucose /sugar to ethanol and carbon dioxide by the action of enzymes in yeast at 20°C
• [ ] Glucose ➡️ethanol + Carbon dioxide

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Uses of ethanol

• Cosmetics
• solvents
• achoholic drinks

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Carboxylic acids

• compounds that all contain the same functional group: –COOH

• They have the general formula: CnH2n+1COOH

• They are colourless liquids

• They react with alkaline solutions, turn blue litmus red and form salts called ethanoates

• They have the general formula: CnH2n+1COOH

  

• Two methods used to make carboxylic acids are:

1.Oxidation by fermentation

2.Using oxidising agents

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Esters

• Alcohols and carboxylic acids react to make esters in esterification reactions
• Esters are compounds with the functional group R-COO-R
• Esters are sweet-smelling oily liquids used in food flavourings and perfumes
• Ethanoic acid will react with ethanol in the presence of concentrated sulfuric acid (catalyst) to form ethyl ethanoate

Naming esters

• The first part of the name indicates the length of the carbon chain in the alcohol
• it ends with the letters ‘- yl’
• The second part of the name indicates the length of the carbon chain in the carboxylic acid
• and it ends with the letters ‘- oate’

Polymers

• Polymers are large molecules built by linking 50 or more smaller molecules called monomers
• Synthetic polymers are ones made in a factory, for example nylon.

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