1. Free radical substitution Eletrophilic addition Nucleophilic substitution Elimination Addition – Elimination Electrophilic substitution Esterification Alkaline hydrolysis Nucleophilic addition ORGANIC REACTION MECHANISMS AS A2 Dehydration Friedel-Crafts Bromination Nitration Acylation Addition polymerisation Bond fission Hydration of alkene Formation of polypeptides Formation of polyamides Formation of polyesters Bromination of alkene

2. BOND FISSION + 2 x Free radicals (= an unpaired electron) Electrophile Nucleophile (= electron pair acceptor) (= electron pair donor) (Breaking of the bond) Reaction of ALKANES = Free radical substitution Reaction of ALKENES = Electrophilic addition HOMOLYTIC FISSION HETEROLYTIC FISSION Curly arrow One electron moving A pair of electrons moving Br Br Br Br Br Br + Br - Homolytic fission Heterolytic fission Br 2 Br +. + Br - Br 2 2 Br .

3. Initiation Propagation Termination FREE RADICAL SUBSTITUTION MECHANISM Least favourable Possible Major organic product + + + + + + + Most favourable Initiation Propagation Termination Br Br Br Br Br Br 2 Br 2 Br 2 Br C H H H H Br C H H H C H H H C H H H Br H Br H Br H Br Br C H H H C H H H Br Br Br Br C H H Br H C H H Br H H Br Br Br Br Br Br 2 Br  Br 2 CH 3 + Br 2  CH 3 Br + Br CH 4 + Br  CH 3 + HBr Br 2  2 Br C H H H C H H C H H H H H 2 CH 3  H 3 C-CH 3 C H H H C H H H Br C H H H C H H H C H H Br H H 3 C + Br  CH 3 Br

4. 2-methylpropene  -  + Carbocation (Electrophile) : Br - Nucleophile BROMINATION OF ALKENE 1,2-dibromo-2-methylpropane C C H 3 C H 3 C H H Br Br C + C Br H 3 C H 3 C H H C C Br Br H 3 C H 3 C H H

5. HYDRATION OF ALKENE MECHANISM 2-methylpropene H + 2-methylpropan-1-ol H + C C H 3 C H 3 C H H C + C H H 3 C H 3 C H H O H H C C H O + H 3 C H 3 C H H H H C C H O H 3 C H 3 C H H H

6. Trigonal planar + + Repeat unit Repeat unit = Any 2 consecutive C along the C chain Chloroethene Polychloroethene 120 o Trimer Monomer Dimer ADDITION POLYMERISATION MECHANISM H Cl H C = C H Cl H C = C H H Cl H C C H H Cl H C = C H H Cl H C C H H Cl H C C H H Cl H C = C H H Cl H C C H H n or

7. NUCLEOPHILIC SUBSTITUTION MECHANISM ELECTRON CLOUD from the nucleophile SHIFTS toward  + C atom, and a DATIVE COVALENT BOND starts to form. As this happens, the C – X bond is WEAKENS and eventually BREAKS HETEROLITICALLY . OH - Cl - δ + δ - + + R - X + :Nu - R - Nu + :X - δ+ δ- H C H Cl H H C H HO H

8. ELIMINATION MECHANISM H 2 O + + H Cl H C H C H H OH - Cl - Cl H C H C H H - H C H C H H

9. H + + DEHYDRATION + H + H O H C H C H H H H O H C H C H H H H + H H C C H H O H H

10. + + H 2 O + ESTERIFICATION MECHANISM Protonation Nucleophilic attack Proton transfer Water elimination Proton elimination C O HO R H O R H + C O HO R H + C O HO R + H O R H H H C O HO R O R + R C O R O + H + H C O R O R

11. ADDITION-ELIMINATION MECHANISM (NUCLEOPHILIC SUBSTITUTION) δ+ δ- δ + δ - Nucleophilic addition Elimination Nucleophilic substitution δ + δ - + + Cl - HO C H O δ+ δ- Cl C H O OH - δ+ δ- C O - OH H Cl

12. ALKALINE HYDROLYSIS MECHANISM Nucleophilic attack Break down of the tetrahedral intermediate Proton transfer OH - R C O R O C O - R HO Na + O R O - R Na + C O R O H OH R C O R O - Na +

13. NITRATION Formation of the electrophile: NO 2 + nitronium ion Regeneration of the catalyst: Electrophilic substitution: HSO 4 - C 6 H 6 + HNO 3 C 6 H 5 NO 2 + H 2 O Overall equation: H 2 SO 4 cat. 50 o C NO 2 + NO 2 + H H NO 2 H + + HNO 3 + H 2 SO 4 H 2 NO 3 + + HSO 4 - H 2 NO 3 + H 2 O + NO 2 + H + + HSO 4 - H 2 SO 4 HNO 3 + H 2 SO 4 H 2 O + NO 2 + + HSO 4 -

14. BROMINATION Formation of the electrophile: Br + Regeneration of the catalyst: Electrophilic substitution: FeBr 4 - C 6 H 6 + Br 2 C 6 H 5 Br + HBr Overall equation: FeCl 3 cat. Br + Br + H H Br H + + Br 2 + FeBr 3 Br + + FeBr 4 - H + + FeBr 4 - FeBr 3 +HBr

15. FRIEDEL-CRAFT MECHANISM Formation of the electrophile: CH 3 + Regeneration of the catalyst: Electrophilic substitution: FeCl 4 - C 6 H 6 + CH 3 Cl C 6 H 5 CH 3 + HCl Overall equation: FeCl 3 cat. CH 3 + CH 3 + H H CH 3 H + + CH 3 Cl + FeCl 3 CH 3 + + FeCl 4 - H + + FeCl 4 - FeCl 3 + HCl

16. ACYLATION MECHANISM Formation of the electrophile: CH 3 CO + Regeneration of the catalyst: Electrophilic substitution: FeCl 4 - C 6 H 6 + CH 3 COCl C 6 H 5 COCH 3 + HCl Overall equation: FeCl 3 cat. COCH 3 + COCH 3 + H H COCH 3 H + + CH 3 COCl + FeCl 3 CH 3 CO + + FeCl 4 - H + + FeCl 4 - FeCl 3 + HCl

17. N Ξ C - δ + δ - NUCLEOPHILIC ADDITION MECHANISM oxoanion Dative covalent bond formation  bond weakens and breaks heterolytically This reaction is useful because the chain is extended by 1 carbon. 2-hydroxynitrile Dative covalent bond formation  bond weakens and breaks heterolytically δ + δ - + + C H O H H C H N Ξ C O - H C Ξ N H C H N Ξ C O H - C Ξ N

18. + + Peptide link (amide) FORMATION OF POLYPEPTIDES Repeat unit (aminoacid residue) Peptide link (amide) + 2 H 2 O Monomer 2-amino acid Trimer C H R N O OH C H H C H R N O C H H OH` C H R N O OH C H H OH C H R N O C H C H R N O C H H C H R N O C H C H R N O C H n

19. + + + Peptide link (amide) Repeat unit Repeat unit 2 monomers +3 H 2 O DIBASIC ACID and DIAMINE to form POLYAMIDES Peptide link (amide) Peptide link (amide) (CH 2 ) n N H H N H H O (CH 2 ) n OH C O OH C (CH 2 ) n N H H N H H (CH 2 ) n O OH C O OH C (CH 2 ) n N H N H H (CH 2 ) n N H N H (CH 2 ) n O C O C (CH 2 ) n O C O OH C O OH C (CH 2 ) n O C O C Repeat unit (CH 2 ) n N H N H

20. Ester link + + Ester link Ester link + 3 H 2 O + REACTION OF DIBASIC ACID and DIOL to form POLYESTERS OH O C HO O C (CH 2 )n OH O C HO O C (CH 2 )n (CH 2 ) n O H O H O C HO O C (CH 2 )n O C O C (CH 2 )n H (CH 2 ) n O O Repeat unit (2 monomers) (CH 2 ) n O H O H (CH 2 ) n O O H O C O C (CH 2 )n H (CH 2 ) n O O Repeat unit (2 monomers)