文档介绍：Chapter 6 Alkyl Halides: Nucleophilic Substitution and Elimination
Organic Chemistry, 5th Edition L. G. Wade, Jr.
Jo Blackburn
Richland College, Dallas, TX
Dallas munity College District
ã 2003, Prentice Hall
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Chapter 6
Classes of Halides
Alkyl: Halogen, X, is directly bonded to sp3 carbon.
Vinyl: X is bonded to sp2 carbon of alkene.
Aryl: X is bonded to sp2 carbon on benzene ring. Examples:
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Chapter 6
Polarity and Reactivity
Halogens are more electronegative than C.
Carbon-halogen bond is polar, so carbon has partial positive charge.
Carbon can be attacked by a nucleophile.
Halogen can leave with the electron pair. =>
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Chapter 6
Classes of Alkyl Halides
Methyl halides: only one C, CH3X
Primary: C to which X is bonded has only one C-C bond.
Secondary: C to which X is bonded has two C-C bonds.
Tertiary: C to which X is bonded has three C-C bonds. =>
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Chapter 6
Classify These:
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Chapter 6
Dihalides
Geminal dihalide: two halogen atoms are bonded to the same carbon
Vicinal dihalide: two halogen atoms are bonded to adjacent carbons.
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Chapter 6
IUPAC Nomenclature
Name as haloalkane.
Choose the longest carbon chain, even if the halogen is not bonded to any of those C’s.
Use lowest possible numbers for position.
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Chapter 6
mon Names
Name as alkyl halide.
Useful only for small alkyl groups.
Name these:
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Chapter 6
“Trivial” Names
CH2X2 called methylene halide.
CHX3 is a haloform.
CX4 is carbon tetrahalide.
Examples:
CH2Cl2 is methylene chloride
CHCl3 is chloroform
CCl4 is carbon tetrachloride. =>
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Chapter 6
Uses of Alkyl Halides
Solvents - degreasers and dry cleaning fluid
Reagents for synthesis of pounds
Anesthetic: Halothane is CF3CHClBr
CHCl3 used originally (toxic and carcinogenic)
Freons, chlorofluorocarbons or CFC’s
Freon 12, CF2Cl2, now replaced with Freon 22, CF2CHCl, not as harmful to ozone layer.
Pesticides - DDT banned in . =>
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Chapter 6