1. 20.4 Condensation Reactions

2. Assessment Statements 20.4.1 Describe, using equations, the reactions with alcohol with carboxylic acids to form esters and state the uses of esters. 20.4.2 Describe, using equations, the reactions with amines with carboxylic acids. 20.4.3 Deduce the structures of the polymers formed in the reactions of alcohols with carboxylic acids. 20.4.4 Deduce the structures of the polymers formed in the reactions with amines and carboxylic acids. 20.4.5 Outline the economic importance of condensation reactions

3. Assessment Statements 20.4.1 Describe, using equations, the reactions with alcohol with carboxylic acids to form esters and state the uses of esters. 20.4.3 Deduce the structures of the polymers formed in the reactions of alcohols with carboxylic acids.

4. Condensation reactions Condensation reactions result from the addition of two molecules with the elimination of water molecules. IMPORTANT in biological systems (IB biolog students maybe able to recognise where these are used). An example of a condensation reaction is ESTERIFICATION. Carboxylic acid + Alcohol (acid catalyst)  Ester and water

5. Most esters have very distinctive smells. Generally fruity used as scents for perfumes or air fresheners and food flavourings Also used as painkillers, solvents and anaesthetics

6. Some Esters

7. Benzene Structures Painkillers such as aspirin include esters

8. Alcohols can contain more that one hydroxyl group (OH) and carboxylic acid groups (COOH) so can link to form POLYESTERS Multiple OH groups Multiple COOH groups Groups can still undergo further esterification

9. Polyesters

10. Dipole/dipole interactions between the polar chains interact with one another. Used in textiles (e,g, shirts) and plastics. This is TERYLENE (Dacron) used to make clothing in cotton/polyester blends

11. Assessment Statements 20.4.2 Describe, using equations, the reactions with amines with carboxylic acids. 20.4.4 Deduce the structures of the polymers formed in the reactions with amines and carboxylic acids.

12. Amines with Carboxylic Acids

13. Example

14. Polymerisation Reactions Nylons is the polymerisation of amines and carboxylic acids. Same principle as polymerisation of carboxylic acids and alcohols where the molecules have two amine groups or two carboxylic acid groups.

15. The two monomers each have six carbon chains so it is called nylon 6,6

16. The Repeating Unit For Nylon 6,6

17. Nylon in Industry The reactions to form nylon are carried out in a vacuum so as to assist in the removal of the released water (remember, it is a condensation reaction) Nylon is known as a POLYAMIDE It is the same link as in PEPTIDE BONDS in POLYPEPTIDES in PROTEINS. Nylon is produced in a solid form and can be melted and passed through jets which produces NYLON FIBRES. The resultant product can then be woven for rope, fabrics, parachutes, bags etc

18. Hydrogen Bonding Hydrogen bonds hold the strands together between the NH and CO groups.

19. Further Uses

20. Assessment Statements 20.4.5 Outline the economic importance of condensation reactions

21. Just to Summarise Condensation reactions are used to make Perfumes Flavourings Painkillers Solvents Anaesthetics Plastics (e.g kevlar) Polyesters Nylons (Polyamides) Making Proteins

22. The worlds nylon production is estimated to exceed 5 million tonnes Clothes carpets, ropes etc High strength, resists abrasion and easy to dye. Used in engineering to replace metals (gears, etc) Kevlar now used to reinforce many materials.

23. Diagram of common organic reactions HL 23