Chapter 12 Unsaturated Hydrocarbons 12 5 Aromatic Compounds

Chapter 12 Unsaturated Hydrocarbons 12. 5 Aromatic Compounds 1

Aromatic Compounds Benzene is • an aromatic compound. • a ring of 6 C atoms and 6 H atoms. • a flat ring structure drawn with three double bonds. • represented by two structures because the electrons are shared among all the C atoms. Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings 2

Benzene Structure Benzene • has 6 electrons shared equally among the 6 C atoms. • is also represented as a hexagon with a circle drawn inside. 3

Aromatic Compounds in Nature and Health Vanillin Ibuprofen Aspirin Acetaminophen 4

Naming Aromatic Compounds Aromatic compounds are named • with benzene as the parent chain. • with one side group named in front of benzene. methylbenzene chlorobenzene 5

Some Common Names Some substituted benzene rings • have common names that have been in use for many years. • with a single substituent use a common name or are named as a benzene derivative. toluene (methylbenzene) aniline (benzenamine) phenol (hydroxybenzene) 6

Naming Aromatic Compounds When two groups are attached to benzene ring, the ring is numbered to give the lowest numbers to the side groups. 3 -chlorotoluene 1, 4 -dichlorobenzene 2 -chlorophenol 7

Learning Check Select the correct name for each compound. 1) chlorocyclohexane 2) chlorobenzene 3) 1 -chlorobenzene 1) 1, 2 -dimethylbenzene 2) 1, 4 -dimethylbenzene 3) 1, 3 -dimethylbenzene 8

Solution Select the correct name for each compound. 2) chlorobenzene 3) 1, 3 -dimethylbenzene 9

Learning Check Write the structural formulas for each of the following. A. 1, 3 -dichlorobenzene B. 2 -chlorotoluene 10

Solution Write the structural formulas for each of the following. A. 1, 3 -dichlorobenzene B. 2 -chlorotoluene 11

Learning Check Identify the organic family for each: A. CH 3─CH 2─CH=CH 2 B. C. CH 3─C≡CH D. 12

Solution Identify the organic family for each: A. CH 3─CH 2─CH=CH 2 alkene B. cycloalkane (alkane) C. CH 3─C≡CH alkyne D. aromatic 13