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Carboxylic Acids and Esters

Carboxylic Acids and Esters. Describe the chemical and physical properties of carboxylic acids and esters Explain how an ester can be made. What do you remember about alcohols?. Miscible in water OH Hydroxyl Homologous series. Carboxylic acids.

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Carboxylic Acids and Esters

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  1. Carboxylic Acids and Esters • Describe the chemical and physical properties of carboxylic acids and esters • Explain how an ester can be made

  2. What do you remember about alcohols? • Miscible in water • OH • Hydroxyl • Homologous series

  3. Carboxylic acids • Carboxylic acids contain the -COOH group, which is written out in full is: • Carboxylic acids are shown by the ending oic acid. When you count the carbon chain, you have to remember to include the carbon in the -COOH group.

  4. Alcohols Carboxylic Acids

  5. Practical 1 Part 1: Reactions of dilute ethanoic acid • Test a little ethanoic acid with universal indicator. What is the pH? • Fill a tube about one-third full with dilute ethanoic acid. Add a piece of magnesium. Note your observations and test the gas that is given off. • Fill a tube about one-third full with dilute ethanoic acid. Add a spatula of sodium hydrogen carbonate. Note your observations and test the gas that is given off. • Repeat step C using sodium carbonate. • Record your results neatly in a table.

  6. Fill in the equations for the practical in part 1 • magnesium  _________ ___________  magnesium ethanoate  _________ • sodium _________ ethanoic acid  _________ ethanoate  _________ __________ water

  7. H H H O H-C-C O-C-C-H H H H Making an Ester Esters are made by reacting a carboxylic acid with an alcohol (a base). Esters are organic salts. Ethanoic Acid + Ethanol H O-H Ethyl ethanoate + Water CH3COOC2H5 H2O

  8. Practical 2 Practical 2 Part 2: Making an ester • Pour some boiling water into a 250 cm3 beaker. • Put about 2 cm3 of ethanol into a test tube. • Go to the fume cupboard and ask your teacher to add 1 cm3 of concentrated ethanoic acid and three drops of concentrated sulphuric acid to your tube. • Stand your tube in the beaker of hot water for about 5 minutes. • While you are waiting, collect a 100 cm3 beaker and fill it about half full with sodium hydrogen carbonate solution. • After 5 minutes, carefully tip the liquid from the test tube into the beaker and stir well. • Carefully smell the product in the beaker.

  9. Ethanol + ethanoic acid Propanol + ethanoic acid Butanol + ethanoic acid Ethanol + propanoic acid Ethanol + benzoic acid Esters are named by joining the name of the alcohol with the name of the acid. Ethyl ethanoate Propyl ethanoate Butyl ethanoate Ethyl propanoate Ethyl benzoate

  10. O H H - C – O - C - H H A guide to naming esters • Firstly the C=O in the ester must come last. Turn it around if it isn't. • Split it into two. The part attached to the O on the left hand side is from the alcohol, and the C=O is from the acid.

  11. O H H H - C - C– O - C - H H H H H ethanol H – C – C - O - H This bit of the ester came from the alcohol This bit of the ester came from the acid H H methanoic acid O H – O - C - H The original ester is ethyl methanoate

  12. Whichalcohols and carboxylic acids were these esters formed from?

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