1. Main Menu Lesson 9 Meet the Families Part 2 – The Revenge of Father-in-Law

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3. Main Menu Lesson 9: Meet the Families….again  Objectives:  Learn to recognise and name a further 4 functional groups  Use molecular models to build the above

4. Main Menu Functional Groups Mind map  You need to add these functional groups to your mind map from lesson 3:  Amide  Amine  Nitrile  Ester – with the full detail now  For each one you should include:  General structural formula  Rules for naming them (including the position where relevant)  With an example  Relative volatility and solubility in water  For amines you should include a branch to explain the difference between 1 o, 2 o and 3 o  You should spend time looking in more detail at the naming of the amines and amides as the N atom can complicate things

5. Main Menu Building Organic Compounds  Use molecular models to make any of the compounds mentioned in your mind-map:  Draw it (structural and skeletal)  Name it  Give it to a friend and challenge them to do the same  Only go up to 6 carbons  Only include branched-chains for the alkanes

6. Main Menu Key Points  There are 11 functional groups we need to know in detail and 1 extra we need to be able to recognise  We will look at each in detail at the 4 new ones over the rest of the unit

7. Main Menu Lesson 10 S N 1 and S N 2 Revisited

8. Main Menu Refresh  What is the IUPAC name of the compound CH 3 CH 2 COOCH 2 CH 3 ? A. Ethyl ethanoate B. Propyl ethanoate C. Ethyl propanoate D. Pentyl propanoate Reviewing Your Notes You should spend 60 seconds reviewing your notes from last lesson before attempting this. Your notes and mind-map must be ready for me to inspect.

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10. Main Menu Lesson 10: S N 1 and S N 2 Revisited  Objectives:  Understand why the nature of the halogenoalkane effects the mechanism of nucleophilic substitution reactions  Understand why OH - is a better nucleophile than H 2 O  Understand the effect of the halogen on the rate of nuclephilic substitution reactions  Complete a short investigation into the factors affecting the rate of nucleophilic substitution

11. Main Menu S N 1 and S N 2 Recap

12. Main Menu S N 1 and the carbocation  The carbocation is an unstable species, and will often immediately attract the halide ion straight back  Alkyl groups surrounding the carbocation donate electron charge to it and stabilise it  In this diagram, the arrows on the bonds represent the charge donated by the surrounding alkyl groups  3 o carbocations have most surrounding alkyl groups and therefore are most stable, thus S N 1 is preferred for 3 o halogenoalkanes

13. Main Menu Mechanism and rate  For S N 1:rate = k[halogenoalkane]  For S N 2:rate = k[halogenoalkane][nucleophile]  Since S N 1 only depends on one reactant, it tends to be faster (all else being equal) than S N 2  Therefore, if we consider the rates of hydrolysis / substitution, as a rule of thumb: Tertiary > Secondary > Primary

14. Main Menu S N 2 and steric hindrance  Alkyl groups are physically bulky, and make it difficult for a nucleophile to attack the carbon: this is called steric hindrance  1 o halogenoalkanes only have one surrounding alkyl group so steric hindrance is low and SN2 is favourable  3 o halogenoalkanes have three surrounding alkyl groups so steric hindrance is high and SN2 is unfavourable  The black arrows on the diagram are supposed to show possible avenues of approach by the nucleophile, red crosses show where they are blocked

15. Main Menu Changing the Nucleophile  Water can act as our nucleophile:  Halogenoalkane + water  alcohol + hydrogen halide  However, hydroxide is much better. Why?  Explain why using ideas from the bonding unit

16. Main Menu Changing the Halogen  The rate of substitution / hydrolysis varies greatly depending on the halogen atom  As a rule, with all else being equal, the rate changes as follows: Iodine > Bromine > Chlorine  Explain why using ideas from the bonding unit

17. Main Menu Key Points  The substitution mechanism followed depends on:  Stabilisation of the carbocation by surrounding alkyl groups  Steric hindrance of the carbocation by surrounding alkyl groups  Hydroxide ions are better nucleophiles than water due to their strong negative charge  Iodoalkanes react faster than chloroalkanes due to the C-I bond being weaker than the C-Cl bond

18. Main Menu Lesson 11 More Nucleophiles

19. Main Menu Refresh Which statements about substitution reactions are correct? I. The reaction between sodium hydroxide and 1-chloropentane predominantly follows an S N 2 mechanism. II. The reaction between sodium hydroxide and 2-chloro-2-methylbutane predominantly follows an S N 2 mechanism. III. The reaction of sodium hydroxide with 1- chloropentane occurs at a slower rate than with 1-bromopentane. A. I and II only B. I and III only C. II and III only D. I, II and III Reviewing Your Notes You should spend 60 seconds reviewing your notes from last lesson before attempting this. Your notes and mind-map must be ready for me to inspect.

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21. Main Menu Lesson 11: More Nucleophiles  Objectives:  Understand the reaction of halogenoalkanes with ammonia  Understand the reaction of halogenoalkanes with potassium cyanide  Describe and explain the reduction of nitriles

22. Main Menu More nucleophiles  So far we have met two nucleophiles:  Hydroxide  Water  This lesson we meet two more:  Ammonia, NH3  Cyanide, - CN  Draw the Lewis structure of cyanide  These undergo participate in nucleophilic substitution in exactly the same way as hydroxide and water.

23. Main Menu Key Points  Halogenoalkanes react with:  Ammonia to form primary amines  Further reactions can for secondary and tertiary amines and quaternary ammonium salts  Potassium cyanide to form a nitrile  This is useful as it creates a new C-C bond…no mean feat!  The nitrile can be reduced to an amine by reaction with H 2 and Ni catalyst

24. Main Menu Lesson 12 Elimination Reactions

25. Main Menu Refresh  What is the product of the following reaction? CH 3 CH 2 CH 2 CN + H 2 A. CH 3 CH 2 CH 2 NH 2 B. CH 3 CH 2 CH 2 CH 3 C. CH 3 CH 2 CH 2 CH 2 CH 3 D. CH 3 CH 2 CH 2 CH 2 NH 2 Ni. cat Reviewing Your Notes You should spend 60 seconds reviewing your notes from last lesson before attempting this. Your notes and mind-map must be ready for me to inspect.

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27. Main Menu Lesson 12: Elimination Reactions  Objectives:  Describe with equations the elimination reactions of halogenoalkanes  Describe the mechanism of elimination reactions  Complete an experiment investigating elimination reactions

28. Main Menu Elimination  With warm, aqueous sodium hydroxide, halogenoalkanes undergo substitution  With hot, ethanolic sodium hydroxide an elimination reaction will take place: halogenoalkane + sodium hydroxide  alkene + water + sodium halide

29. Main Menu The mechanism  Similar to substitution, there are unimolecular (E1) and bimolecular (E2) mechanisms:  They work in a similar way to S N 1/2 and are affected by similar factors:  E1:  E2:  You only need remember one (go with E2…shorter), and do not need to know the same level of detail as for substitution

30. Main Menu Key Points  Halogenoalkanes will undergo elimination on reaction with sodium hydroxide if:  It is dissolved in ethanol  Hot  The elimination proceeds by both bimolecular and unimolecular mechanisms

31. Main Menu Lesson 13 Condensation Reactions

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33. Main Menu Lesson 13: Condensation Reactions  Objectives:  Describe with equations the reaction of alcohols with carboxylic acids  Describe with equations the reaction of amines with carboxylic acids  Complete a lovely-smelling esters experiment

34. Main Menu Condensation Reactions  A reaction in which two molecules join together, and produce a molecule of water as a by-product.

35. Main Menu Esterification – the reaction of alcohols and carboxylic acids  Carboxylic acids react with alcohols to make esters:  The ester linkage is outline in red  Carboxylic acid + alcohol ester + water  You may need to review your mind-map for details on naming esters…basically the alcohol gives the ‘-yl’ part and the acid the ‘- oate’ part H + cat

36. Main Menu Amides – the reaction of amines and carboxylic acids  Carboxylic acids react with amines to make amides:  The amide linkage is outlined in red  Carboxylic acid + amine amide + water  You may need to review your mind-map for details on naming esters  The amine gives the ‘-yl’ part and the acid the ‘-anamide’ part, the N- signifies that the alkyl group is attached to the nitrogen  Note the similarity to esterification

37. Main Menu Draw and name the products of the following reactions:  Ethanoic acid with ethanol  Methanoic acid with butylamine  Pentanoic acid with phenol (C 6 H 5 OH)  Propanoic acid with methylamine

38. Main Menu Key Points  Carboxylic acid + alcohol  ester + water  Carboxylic acid + amine  amide + water

39. Main Menu Lesson 14 Condensation Polymerisation

40. Main Menu Refresh  What is the IUPAC name of CH 3 CH 2 CONH 2 ? A. Aminopropanal B. Ethanamide C. Propylamine D. Propanamide Reviewing Your Notes You should spend 60 seconds reviewing your notes from last lesson before attempting this. Your notes and mind-map must be ready for me to inspect.

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42. Main Menu Lesson 14: Condensation Reactions  Objectives:  Describe with equations the condensation reactions of diacids with diols  Describe with equations the condensation reactions of diacids with diamides  Perform the nylon rope-trick

43. Main Menu Polyesters  Polyesters form from monomers containing two functional groups  For example dicarboxylic acids and dialcohols  Each end of each molecule forms an ester linkage, allowing for long chains to build up

44. Main Menu Polyamides  Similar to polyesters, polyamides form from monomers containing two functional groups  For example dicarboxylic acids and diamines  Each end of each molecule forms an amide linkage, allowing for long chains to build up

45. Main Menu A quick note  You can also get condensation polymerisation from monomers containing one of each of the functional groups.  The best example is amino acids and proteins:

46. Main Menu Key Points  Polyesters form from monomers containing two acid and two alcohol groups  Polyamides form from monomers containing two acid and two amine groups

47. Main Menu Lesson 15 Geometrical Isomerism

48. Main Menu Refresh Which formula represents a polyamide? A. ( CH 2 –CHCl ) n B. ( NH–(CH 2 ) 6 –NH–CO–(CH 3 ) 4 – CO ) n C. ( CF 2 –CF 2 ) n D. ( O–(CH 2 ) 2 –O–CO–--–CO ) n Reviewing Your Notes You should spend 60 seconds reviewing your notes from last lesson before attempting this. Your notes and mind-map must be ready for me to inspect.

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50. Main Menu Lesson 15: Geometrical Isomerism  Objectives:  Understand the term stereoisomerism  Understand and identify geometrical isomerism  Understand the chemical significance of cis-trans isomerism

51. Main Menu Stereoisomerism  Stereoisomers are compounds with the same structural formula but different 3D arrangement of atoms  There are two types of stereoisomerism:  Geometrical isomerism  Optical isomerism

52. Main Menu Geometrical (cis-trans isomerism)  It happens because double bonds are not free to rotate  Each C=C carbon must have two different groups attached to it.  In the trans isomer, the substituents (the –CH3 groups) are on opposite sides of the double bond  In the cis isomer, the substituents are on the same side of the double bond  Geometric isomerism involves the arrangement of groups around a double bond  Or a single bond that can’t rotate freely such as in a cyclic compound

53. Main Menu Properties  Chemical and physical properties will often be similar but there can be important differences as you are about to see….

54. Main Menu Chemical properties of geometric isomers  Can be different  For example:  Why do you think this happens?  Hint: think about the previous couple of lessons

55. Main Menu Key Points  Cis isomers: the substituents are on the same side  Trans isomers: the substituents are on opposite sides  Cis alkenes have lower mp/bp than trans due to ‘rounder’ shape  Cis halogenoalkenes have higher mp/bp due to polarity  Chemical properties can be different where cis brings groups close enough to react

56. Main Menu Lesson 16 Optical Isomerism

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58. Main Menu Lesson 16: Optical Isomerism  Objectives:  Understand and identify optical isomerism  Understand the chemical significance of optical isomerism

59. Main Menu Optical Isomerism  Optical isomerism occurs when you have four different groups all bonded to a central atom.  For example: amino acids

60. Main Menu Some terminology  The central carbon is referred to as ‘chiral’  You will see books refer to the ‘chiral carbon’ or ‘chiral centre’  You may see books talking about the ‘chirality’ of a molecule  A molecule might be described as ‘chiral’ if it has a ‘chiral centre’  A carbon must have at least 4 different groups to be chiral  The two optical isomers are referred to as enantiomers  A racemic mixture is a one with a 50:50 mix of the two enantiomers  Enantiomers can be referred to as right or left handed  If you see ‘R-’ or ‘L-’ in a name, this is what they are referring to  There is a standard way to work this out but we don’t need it!

61. Main Menu Properties of optical isomers  Enantiomers share virtually identical chemical and physical properties  However:  Two enantiomers will rotate plane- polarised light in opposite directions…hence the term ‘optical isomerism’  More on the next slide  Chemical properties differ significantly in chemical systems where 3D-shape is important, particularly biochemistry  The image above right shows an enzyme, these are sensitive to the exact shape of a molecule

62. Main Menu Rotation of plane-polarised light  Light normally vibrates in many different directions  Plane-polarised light only vibrates in one direction  A pure solutions of enantiomers rotate the plane- polarised light in opposite directions  A racemic mixture will not rotate light as the rotations from each enantiomer cancel each other out  This rotation can be detected using a polarimeter

63. Main Menu Key Points  Optical isomers (enantiomers) rotate plane-polarised light in opposite directions  To display optical activity, a compound must have at least four different groups attached to the same atom  The central atom is referred to as chiral

64. Main Menu Lesson 17 Reaction Pathways – Boss Level

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66. Main Menu Lesson 17: Reaction Pathways Again  Objectives:  Add the HL reactions to the reaction pathways diagram  Set your classmates challenges involving navigation around the diagram

67. Main Menu Some Challenges  Use your reaction pathways diagrams to help you solve the following problems  Butylamine can be produced from propane in three steps. Give the reaction conditions and draw the intermediate products for each step  Ethyl ethanoate can be prepared from ethene over several steps. Outline how you might do this, naming the intermediate products and giving suitable reaction conditions

68. Main Menu Key Points  Inter-converting between organic compounds is the bread and butter of an organic chemist  Reaction pathways are the map that help you navigate from your point of origin to your destination