文档介绍：Chapter 3 Structure and Stereochemistry of Alkanes
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 3
Alkane Formulas
All C-C single bonds
Saturated with hydrogens
Ratio: CnH2n+2
Alkane homologs: CH3(CH2)nCH3
Same ratio for branched alkanes
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Chapter 3
Common Names
Isobutane, “isomer of butane”
Isopentane, isohexane, etc., methyl branch on next-to-last carbon in chain.
Neopentane, most highly branched
Five possible isomers of hexane, 18 isomers of octane and 75 for decane! =>
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Chapter 3
Pentanes
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Chapter 3
IUPAC Names
Find the longest continuous carbon chain.
Number the carbons, starting closest to the first branch.
Name the groups attached to the chain, using the carbon number as the locator.
Alphabetize substituents.
Use di-, tri-, etc., for multiples of same substituent. =>
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Chapter 3
Longest Chain
The number of carbons in the longest chain determines the base name: ethane, hexane. (Listed in Table , page 81.)
If there are two possible chains with the same number of carbons, use the chain with the most substituents.
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Chapter 3
Number the Carbons
Start at the end closest to the first attached group.
If two substituents are equidistant, look for the next closest group.
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Chapter 3
Name Alkyl Groups
CH3-, methyl
CH3CH2-, ethyl
CH3CH2CH2-, n-propyl
CH3CH2CH2CH2-, n-butyl
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Chapter 3
Propyl Groups
H
n-propyl
isopropyl
H
A primary carbon
A secondary carbon
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Chapter 3
Butyl Groups
n-butyl
sec-butyl
H
H
A primary carbon
A secondary carbon
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Chapter 3