Chapter 13 Unsaturated Hydrocarbons

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Chapter 13Unsaturated Hydrocarbons

• CHEM 2124 General Chemistry II
• Alfred State College
• Professor Bensley

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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.

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Chapter 13 Objectives

• Draw the products of reactions that follow
  Markovnikovs Rule.
• Draw the structure of polymers that are formed
  from alkene monomers.
• Draw the products of substitution reactions of
  benzene.

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Chapter 13 Unsaturated Hydrocarbons
I. Alkenes and Alkynes

1. Alkenes

1. Alkynes

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Chapter 13 Unsaturated Hydrocarbons

1. Alkene and Alkyne Properties

• What are unsaturated hydrocarbons?
• Drawing Condensed Structures

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Nomenclature of Alkenes and Alkynes
HOW TO Name an Alkene or Alkyne
Find the longest chain that contains both C atoms
of the double or triple bond.
Step 1
6 Cs in longest chain
4 Cs in longest chain
butane ----gt butene
hexane ----gt hexyne
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Nomenclature of Alkenes and Alkynes
HOW TO Name an Alkene or Alkyne
Number the carbon chain from the end that gives
the multiple bond the lower number.
Step 2
2-hexyne
1-butene
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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?
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Chapter 13 Unsaturated Hydrocarbons
D. Cycloalkenes
2
1
2
CH3
1
CH3
CH3
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1-methylcyclopentene
1,6-dimethylcyclohexene
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Chapter 13 Unsaturated Hydrocarbons
II. Stereoisomers
2-butene
A. Cis/trans isomers
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Chapter 13 Unsaturated Hydrocarbons
B. Stereoisomers vs. Constitutional Isomers
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Interesting Alkenes in Food and Medicine
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Chapter 13 Unsaturated Hydrocarbons
III. Reactions of Alkenes

1. Addition Reactions

1. Hydrogenation
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Chapter 13 Unsaturated Hydrocarbons
2. Halogenation
3. Hydrohalogenation
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Chapter 13 Unsaturated Hydrocarbons
4. Markovnikovs Rule
C2 is bonded to 1 H C1 is bonded to 2 Hs

• C1 has more Hs, so it will bond to the H from
  HCl.

• 2-Chloropropane is the only product formed.

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Chapter 13 Unsaturated Hydrocarbons
5. Hydration
this C has no Hs
CH3
CH3
OH
H2SO4

H
OH
H
H
H
this C has 1 H
only product
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Figure 13.4
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Chapter 13 Unsaturated Hydrocarbons
IV. Aromatic Compounds
What is a resonance hybrid?
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Chapter 13 Unsaturated Hydrocarbons
A. Nomenclature of Aromatic Compounds
1. One substituent
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Chapter 13 Unsaturated Hydrocarbons
2. Disubstituted Benzenes
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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
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2,5-dichloroaniline

• Some common drugs that contain benzene
• rings are

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