Chapter Organic Chemistry Alkanes and Aromatic Hydrocarbons Cycloalkanes Aromatic Hydrocarbons Timberlake LecturePLUS 1999

Timberlake LecturePLUS 1999 Cycloalkanes Cyclopropane CH2 CH2 CH2 Cyclobutane CH2 CH2 The is a group of alkanes that have a cyclic structure. These cycloalkanes contain a carbon chain that is in a ring. Each cycloalkane has a formula that is 2C less than the corresponding alkane. For example, propane is C3H8 whereas cyclopropane ic C3H6. Butane is C4H10 and cyclobutane is C4H10. The names of the cyclic structures use the prefix cyclo in from of the alkane name for the carbon chain. Timberlake LecturePLUS 1999

Timberlake LecturePLUS 1999 More Cycloalkanes Cyclopentane CH2 CH2 CH2 CH2 CH2 Cyclohexane CH2 Timberlake LecturePLUS 1999

Naming Cycloalkanes with Side Groups Number of Naming side groups One Side group name goes in front of the cycloalkane name. Two Number the ring in the direction that gives the lowest numbers to the side groups. Timberlake LecturePLUS 1999

Cycloalkanes with Side Groups Timberlake LecturePLUS 1999

Timberlake LecturePLUS 1999 Learning Check Alk8 Timberlake LecturePLUS 1999

Timberlake LecturePLUS 1999 Solution Alk8 Timberlake LecturePLUS 1999

Aromatic Compounds and Benzene Aromatic compounds contain benzene. Benzene, C6H6 , is represented as a six carbon ring with 3 double bonds. Two possible can be drawn to show benzene in this form. Timberlake LecturePLUS 1999

Timberlake LecturePLUS 1999 Benzene Structure The structures for benzene can also be written as a single structure where the alternating double bonds are written as a circle within the ring. Benzene structure Timberlake LecturePLUS 1999

Aromatic Compounds in Nature and Health Many aromatic compounds are common in nature and in medicine. Timberlake LecturePLUS 1999

Naming Aromatic Compounds Aromatic compounds are named with benzene as the parent chain. One side group is named in front of the name benzene. methylbenzene chlorobenzene (toluene) Timberlake LecturePLUS 1999

Naming Aromatic Compounds When two groups are attached to benzene, the ring is numbered to give the lower numbers to the side groups. The prefixes ortho (1,2), meta (1,3-) and para (1,4-) are also used. Timberlake LecturePLUS 1999

Timberlake LecturePLUS 1999 Some Common Names Some substituted benzene rings also use a common name. Then naming with additional more side groups uses the ortho-, meta-, para- system. Timberlake LecturePLUS 1999

Timberlake LecturePLUS 1999 Learning Check Alk9 Select the names for each structure: 1. Chlorocyclohexane 2. Chlorobenzene 3. 1-chlorobenzene 1. 1,2- dimethylbenzene 2. Meta-dimethylbenzene 3. 1,3-dimethylbenzene Timberlake LecturePLUS 1999

Timberlake LecturePLUS 1999 Solution Alk9 Select the names for each structure: 2. Chlorobenzene 2. Meta-dimethylbenzene 3. 1,3-dimethylbenzene Timberlake LecturePLUS 1999

Learning Check Alk10 Write the structural formulas for each of the following: A. 1,3-dichlorobenzene B. Ortho-chloromethylbenzene

Solution Alk10 Write the structural formulas for each of the following: A. 1,3-dichlorobenzene B. Ortho-chloromethylbenzene