Nomenclature of Aromatic Hydrocarbons
Benzene is the most common aromatic parent structure.
a. The benzene ring is named as a
phenyl group when it is a substituent.phenylethyne
b. Multiple substituents on a benzene ring are numbered to give these substituents the lowest possible numbers.
When only two substituents are attached to a benzene ring, they can be named by the common nomenclature using ortho (o-) (1-2 placement), meta (m-) (1-3 placement) or para (p-) (1-4 placement).·
Try to name the following compounds using both conventions... 
*
Try to draw structures for the following compounds...1,2,4-trimethylbenzene
Jp-dimethylbenzene
Jc. Some common names involving benzene rings that you should know are...
toluene
ortho
-xylene
·
Try to draw structures for the following compounds...meta-xylene J
para-xylene J
biphenyl...Notice the numbering convention for this compound.
·
Try to draw a structure for the following compound...2,3'-dimethylbiphenyl
Jbenzyl group
styrene
polystyrene
d. Polycyclic aromatic hydrocarbons that you should know are...
naphthalene
A common nomenclature if only one substituent is on the naphthalene ring system involves the use of
*
Try to name the following compounds using both conventions...*
Try to draw structures for the following compounds...a
-isopropylnaphthalene J1-ethyl-5-methylnaphthalene
Janthracene
phenanthrene
e. The
annulenes are large aromatic rings that have 4n + 2 p electrons in a cyclic conjugated system (n = any whole number including zero). The compound 1,3,5,7-cyclooctatetraene is not an annulene. It has eight p electrons which would yield 1.5 for "n".10-annulene
Copyright © August 2000 by Richard C. Banks...all rights reserved.
