Chemistry Reference
In-Depth Information
AROMATIC ORGANIC CHEMISTRY
S
B
UBSTITUTED
ENZENES
CH
3
CH
CH
3
CH
3
CH
2
CH
3
methylbenzene (toluene)
ethylbenzene
isopropylbenzene
Aromatic compounds can be converted to totally aliphatic compounds
by reaction with hydrogen.
HH
H
H
C
H
2
catalyst
C
C
C
H
H
H
H
C
C
H
H
HH
benzene
cyclohexane
Replacement of an aromatic hydrogen by an aliphatic group is called
alkylation
group. Industrially,
benzene is alkylated by reaction with an olefinic hydrocarbon such as
ethylene to make ethylbenzene, or with propylene to produce isopropylben-
zene. The replaced benzene hydrogen becomes part of the attached group.
Reaction of benzene with hydrogen is one of the few cases in which benzene
reacts like an aliphatic
and the attached group is called an
alkyl
, that is, the hydrogen appears to react as if
discrete double bonds were present.
olefin
