Chemistry Reference
In-Depth Information
AROMATIC ORGANIC CHEMISTRY
S
B
UBSTITUTED
ENZENES
Different groups can be attached to an aromatic ring, for example:
CH
3
CH
3
CH
3
Cl
+
+
Cl
2
Cl
toluene
2-chlorotoluene
4-chlorotoluene
SO
3
H
SO
3
H
+
HNO
3
NO
2
benzenesulfonic acid
3-nitrobenzenesulfonic acid
benzenes are different, the same
three isomers are possible that are possible when the substituents are the
same. Compounds with two different substituents are usually named as
positional derivatives of a monosubstituted (parent) compound. Above, the
common (and commercial) name for methylbenzene is toluene, and the
chlorinated derivatives are named as shown above. However, the same two
chlorinated derivatives can also be properly named 2-chloromethylbenzene
and 4-chloromethylbenzene. In this case, for naming, the parent compound
is methylbenzene and it is understood that the methyl group is in the 1-
position. The terms “
When the two groups in
disubstituted
ortho
-” (1,2-), “
meta
-” (1,3-), and “
para-
” (1,4-) are also
sometimes used; for example, 2-chlorotoluene can be called
-chlorotol-
uene. This can be very confusing, but in the chemical industry, outside of
the research labs, the common names for the parent compounds are almost
always used.
ortho
