1. Aromatic compound
• pleasant fragrance smell(Greek-aroma).
• Benzene and there compound is one such
important aromatic compound.
• Not all aromatic compound have pleasant
smell. Eg. Anthracene.
• Not all pleasant compound is benzene. Eg.
Methyl acetate, chloroform, ethyl acetate.
• We cant detect Aromatic compound with
there smell.
6. Benzene (C6H6)
First synthesis by
berthelot(1870)
Also called arenes.
Aryls – Ar.
Also called phene. Eg.
C6H5 phenyl group.
Colourless, liquid,
odour, B.P. 353K.
PREPARE from
acetylene.
7. Characteristics of aromatic compounds
result burn with
sooty (smoke
release C) flame
Higher percentage of C-atom:-
9. Characteristics of aromatic compounds
Chemical behaviour:-
Substitution rxn- eg.
Halogenation.
Addition rxn – cant
decolourized KMnO4.
10. Structure formula and electronic
structure
• Micheal faraday 1825 – benzene (C6H6).
• unsaturated. Not like alkene and alkyne.
• Cyclic structure 6C-atom alternate double
bond and 1 H-atom attached to each H-atom.
• Kekule suggested the concept of oscillating
nature of double in benzene.
• All C-atom sp2 hybridized.
41. • Electronic dot structure.
• Kekules structure of benzene fails to explain
its unusual stability and substitution rxn.
Which later explain by resonance.
Structure formula and electronic
structure
175. Carcinogenicity and Toxicity
• Carcinogenicity- cancer causing and toxic.
• Polycyclic – hydrocarbon contain 2 benzene
ring fuse together.
• Several polycyclic produce incomplete
combustion of Tabacoo, coal and petroleum.
• In liver, benzene Is oxidized to an
epoxide(cyclic ether).
• benzopyrene converted into epoxydiol. These
substance are carcinogenic and can react
with DNA which stop certain growth of cell.