1. Organic chemistry Topic 20

2. Organic nomenclature [371-373]
Names and structures for functional groups: Amine NH2 Amide CONH2 Ester –COOC– Nitrile CN Exercise 3 and 4 pp

3. Nucleophilic substitution [393-396]
Review
1, 2, and 3 halide [ ]
Why is C-X bond susceptible to nucleophilic attack
What is a nucleophile
Name four good nucleophiles

4. Nucleophilic substitution [393]
Order of reactivity: CN- > OH- > NH3 > H2O
Anions more reactive because higher electron density
Lower electronegativity difference more reactive because electron pair not so tightly bonded

5. Nucleophilic substitution – halogenalkanes [396-397]
Halogen identity and reaction rate
C-I > C-Br > C-Cl
Two opposing factors affect rate
Bond polarity
Bond strength

6. Nucleophilic substitution – halogenalkanes [398-399]
R-X + MOH  R-OH + MX
R-X + MCN  R-CN + MX
R-X + 2NH3  R-NH2 + NH4X
R-X + H2O  R-OH + HX

7. Nucleophilic substitution – halogenalkanes [397]
1 halogen alkane undergo SN2 mechanism
2 halogen alkane undergo either SN1 or SN2
3 halogen alkane undergo SN1 mechanism
SN1 faster than SN2
Rate of hydrolysis 3 > 2 > 1

8. Nucleophilic substitution – halogenalkanes + OH- [394-395]
1 halogen alkane + dilute base (warm)

9. Nucleophilic substitution – halogenalkanes + OH- [394-395]
3 halogen alkane + dilute base (warm)

10. Nucleophilic substitution – halogenalkanes + OH- [394-395]
Exercises 15 and 16 page 396

11. Nucleophilic substitution – halogenalkanes + NH3 [394-395]
Conditions:excess NH3 and warm

12. Nucleophilic substitution – halogenalkanes + KCN [394-395]
Conditions: reflux in ethanol

13. Reduction of nitriles [399]
Product of R-X + MCN  R-CN + MX contains an additional carbon
Chain length has increased
CN triple bond can be reduced with hydrogen and a nickel catalyst
RCN + 2H2  RCH2  NH2
product is an amine
Has one more carbon than formed with direct reaction with ammonia

14. Exercises page 399

15. Elimination Reaction - elimination of HBr from bromoalkane [400-401]
C2H5Br + dilute aqueous OH- at 60  C2H5OH + Br- (substitution) C2H5Br + conc alcoholic OH- at  100  C2H4 + HBr (elimination)

16. elimination of HBr from bromoalkane [400-401]
mechanism

17. elimination of HBr from bromoalkane [400-401]
Exercises page 401

18. Condensation reactions [401-406]
Alcohol + carboxylic acid  ester + water
Amine + carboxylic acid  amide + water

19. Condensation reactions – esters and amides [401-404]

20. Condensation reactions – polyesters and polyamides [404-406]
If using “n” monomers, form (n-1) waters

21. Condensation reactions – polyesters and polyamides [404-406]
Polyester and nylon used for production of fibers to convert into cloth
Major economic importance
Exercises page 406

22. 1-bromopropane  butanamine Exercises 25-27 page 407
Reaction pathways [ ]
1-bromopropane  butanamine Exercises page 407

23. Stereoisomerism [ ]
Stereoisomers are molecules with same structural formula, but arrangement of atoms in space is different
Atoms are joined in same order
Different from structural isomer
Stereoisomers can be divided into
Geometric isomers and optical isomers

24. Geometric isomers [408-410] Occur in alkenes
cis and trans in straight chain and cyclic

25. Geometric isomers [408-410] Different physical properties
Cis isomer usually polar, trans is not
Different polarity, boiling points, melting points, and solubility
Chemical properties are usually similar but sometimes cis or trans presents steric hindrance for reactions

26. Optical isomers [411-415] Also called enantiomers
Contain asymmetric or chiral carbon
Carbon bonded to four different groups
Non superimposable mirror images
Each rotates light a different direction
Use of polarimeter

27. Optical isomers [ ]

28. Optical isomers [ ]
Equal amounts of each enantiomer is racemic mixture
Natural products produced by enzymes are one pure enantiomer, while many man made chemicals are racemic

29. Exercises page 415