The Foundations of Chemistry

Another class of aromatic hydrocarbons consists of “condensed” or “fused-ring”
aromatic systems. The simplest of these are naphthalene, anthracene, and phenanthrene.

No hydrogen atoms are attached to the carbon atoms that are involved in fusion of aromatic
rings, that is, carbon atoms that are members of two or more aromatic rings.
The traditional name is often used as part of the base name in naming an aromatic
hydrocarbon and its derivatives. You should know the names and structures of the aromatic
hydrocarbons discussed thus far: benzene, toluene, the three xylenes, naphthalene,
anthracene, and phenanthrene.
Distillation of coal tar provides four volatile fractions as well as the pitch that is used
for surfacing roads and in the manufacture of “asphalt” roofing (Figure 27-12). Eight
aromatic hydrocarbons obtained in significant amounts by efficient fractional distillation
of the “light oil” fraction are those in Table 27-6.

H

H

H

H

H

H

H

H H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H H

naphthalene, C 10 H 8 anthracene, C 14 H 10 phenanthrene, C 14 H 10

27-6 Other Aromatic Hydrocarbons 1063

TABLE 27-6 Aromatic Hydrocarbons from Coal Tar

Name Formula Normal bp (°C) Normal mp (°C) Solubility

benzene C 6 H 6 80  6

toluene C 6 H 5 CH 3 111  95
o-xylene C 6 H 4 (CH 3 ) 2 144  27

m-xylene C 6 H 4 (CH 3 ) 2 139  54 All insoluble
p-xylene C 6 H 4 (CH 3 ) 2 138  13 in water

naphthalene C 10 H 8 218  80
anthracene C 14 H 10 342  218

phenanthrene C 14 H 10 340  101

Naphthalene.