1. Islamic University of Gaza
Organic chemistry B
Chapters 14, 15, 16
Aromatic Compounds
By Prof. Dr.
Adel M. Awadallah
Islamic University of Gaza

2. Hydrocarbons (contain only carbon and hydrogen)
Aromatic Compounds
Hydrocarbons (contain only carbon and hydrogen)
Saturated: (Contain only single bonds)
Alkanes (CnH2N + 2 )
Cycloalkanes (CnH2N )
b) Unsaturated: contain
Alkenes: double bonds (,,,CnH2N)
Alkynes: triple bonds ((CnH2N - 2)
Aromatic: benzene like compounds

3. Facts about double and triple bonds

4. Structure of Benzene
Benzene is the parent of a class of especially stable compounds called aromatic compounds. It was first isolated by Faraday in 1825 from compressed illuminating gas
Different structures were suggested for benzene (C6H6). The regular conjugated hexagon structure was suggested by Kekuli` in 1865

7. Orbital Model for Benzene

8. Nomenclature of Aromatic Compounds

9. Disubstituted Benzene

10. Assigning Priority
Halogens < alkanes < alkenes < amines < OH < ketone < aldehyde < acid < ester
Examples

11. Aromatic Compounds in Nature and Health

12. Aromatic Character 1) High degree of unsaturation
Aromatic compounds are those that resembles benzene:
1) High degree of unsaturation
2) Do not undergo addition reactions
3) Undergo electrophilic substitution
4) Unusual stability
5) Cyclic five, six, seven
6) flat or nearly flat molecules
7) Delocalized pi clouds must contain a total of
(4N + 2) pi electrons [Hueckel 4n+2 rule]
8) Protons appear around 7 ppm in NMR

13. Resonance Energy of Benzene

16. Hetrocyclic Aromatic Compounds

32. Rearrangement of carbocations

33. Rearrangement of carbocations

37. Reaction of benzene with n-propyl chloride produces isopropyl benzene because of rearrangement

54. How can you prepare the following compound? Starting from benzene

55. Reactions of the side chain of alkylbenzene

56. Arenes: (Alkyl-, Alkenyl- & Alkynylbenzenes)

62. Resonance structure of the allyl radical

63. Triphenylmethyl: a stable free radical

64. Halogenation of the side chain

66. Alkenylbenzenes: Preparation of styrene

72. Polycyclic aromatic compounds cigarettes

73. C60, An aromatic sphere
The Fullerenes