1 Chapter 12 Unsaturated Hydrocarbons 12.5 Aromatic Compounds

2 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. Aromatic Compounds Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

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

4 Aromatic Compounds in Nature and Health VanillinAspirin Ibuprofen Acetaminophen

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

6 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 aniline phenol (methylbenzene) (benzenamine) (hydroxybenzene)

7 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

8 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

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

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

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

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

13 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