Chapter 13 Unsaturated Hydrocarbons CHEM 2124 – General Chemistry II Alfred State College Professor Bensley

Chapter 13 Objectives  Identify the three major types of unsaturated hydrocarbons – alkenes, alkynes, and aromatic compounds.  Name alkanes, alkynes, and substituted benzenes.  Recognize the difference between constitutional isomers and stereoisomers, as well as identify cis and trans isomers.  Draw the products of addition reactions of alkenes.

Chapter 13 Objectives  Draw the products of reactions that follow Markovnikov’s Rule.  Draw the structure of polymers that are formed from alkene monomers.  Draw the products of substitution reactions of benzene.

Chapter 13 – Unsaturated Hydrocarbons I. Alkenes and Alkynes A.Alkenes B.Alkynes

Chapter 13 – Unsaturated Hydrocarbons What are unsaturated hydrocarbons? Drawing Condensed Structures C.Alkene and Alkyne Properties

Nomenclature of Alkenes and Alkynes HOW TO Name an Alkene or Alkyne Step [1] Find the longest chain that contains both C atoms of the double or triple bond. 4 C’s in longest chain butane ----> butene 6 C’s in longest chain hexane ----> hexyne

Nomenclature of Alkenes and Alkynes HOW TO Name an Alkene or Alkyne Step [2] Number the carbon chain from the end that gives the multiple bond the lower number. 1-butene 2-hexyne

Nomenclature of Alkenes and Alkynes HOW TO Name an Alkene or Alkyne Step [3] Number and name the substituents, and write the name. What is a diene?

Chapter 13 – Unsaturated Hydrocarbons CH methylcyclopentene CH ,6-dimethylcyclohexene D. Cycloalkenes

Chapter 13 – Unsaturated Hydrocarbons 2-butene II. Stereoisomers A. Cis/trans isomers

Chapter 13 – Unsaturated Hydrocarbons B. Stereoisomers vs. Constitutional Isomers

Interesting Alkenes in Food and Medicine

Chapter 13 – Unsaturated Hydrocarbons A.Addition Reactions III. Reactions of Alkenes 1. Hydrogenation

Chapter 13 – Unsaturated Hydrocarbons 2. Halogenation 3. Hydrohalogenation

Chapter 13 – Unsaturated Hydrocarbons 4. Markovnikov’s Rule C1 has more H’s, so it will bond to the H from HCl. 2-Chloropropane is the only product formed. C2 is bonded to 1 H C1 is bonded to 2 H’s

Chapter 13 – Unsaturated Hydrocarbons 5. Hydration CH 3 H +HOH this C has no H’s this C has 1 H OH H CH 3 H H 2 SO 4 only product

Figure 13.4

Chapter 13 – Unsaturated Hydrocarbons IV. Aromatic Compounds What is a resonance hybrid?

1. One substituent Chapter 13 – Unsaturated Hydrocarbons A. Nomenclature of Aromatic Compounds

Chapter 13 – Unsaturated Hydrocarbons 2. Disubstituted Benzenes

ortho-xylene o-xylene 1,2-dimethylbenzene meta-xylene m-xylene 1,3-dimethylbenzene para-xylene p-xylene 1,4-dimethylbenzene 3. Polysubstituted Benzenes 4-chloro-1-ethyl-2-propylbenzene

2,5-dichloroaniline Some common drugs that contain benzene rings are:

B. Reactions of Aromatic Hydrocarbons Chapter 13 – Unsaturated Hydrocarbons Addition  NO Substitution  YES

Chapter 13 – Unsaturated Hydrocarbons