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Chapter 13. Alcohols, Phenols, Ethers. Characteristics. Presence of a Oxygen Alcohol: Phenols: Ethers: anesthetics http://www.ethanol.org. Structural Information. Alcohols: Phenols: Ethers: Visualize all three as derived from water. Isomerism. Different skeleton
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Chapter 13 Alcohols, Phenols, Ethers
Characteristics • Presence of a • Oxygen • Alcohol: • Phenols: • Ethers: anesthetics • http://www.ethanol.org
Structural Information • Alcohols: • Phenols: • Ethers: • Visualize all three as derived from water
Isomerism • Different skeleton • Different placement of –OH • C:H same for • C:H same for
Classifying/Naming • 1o, 2o, 3o • Rules: • Find longest chain with the –OH • Ending changed to –ol • Number chain from end nearest –OH • Name and number substituents • Cycloalkanol numbering starts at –OH • Polyfunctional alcohols like 1,2-ethanediol
Physical Properties • High • High • Due to • Tables 13.2 and 13.3 pp 376 and 377 • Which has higher bp? • Boxes pp 378-9
Dehydration of alcohols • Loss of a water molecule • For example: • Opposite process of hydration of alkenes, section 12.6 • 2-butanol • Follows the stability rule: tetrasubstituted alkene > trisubstituted > disubstituted > monosubstituted > unsubstituted
Oxidation of alcohols • Combustion • Selective: must be –OH and –CH and presence of MnO4- or Cr2O7-2 • Primary alcohols • Stage 1: • Stage 2: • Secondary alcohols • Tertiary alcohols
Tests for alcohols • MnO4-: purple solution converted to brown precipitate • Cr2O7-2: orange solution converted to green • Limitations • Distinguish • Ethers • Can’t distinguish
Phenols • -OH attached to a carbon in benzene • Phenol is a parent compound to many important molecules. See box on 389. • Enols: • Naming substituted phenols follows same rules but uses phenol as the base name.
Properties • Phenols are more polar than regular alcohols • Increased • Do not dehydrate
Ethers • Oxygen attached to two • Either • Name using attached groups and “ether” • Common names: page 393
Ethers • There are constitutional isomers • C4H10O: • Higher b.p. than alkanes, but lower b.p. than alcohols
Ether Properties • Soluble in water but not as great as alcohols • Unreactive toward
Formation of ethers • Dehydration of primary alcohols • In the presence of • Dehydration of 1-propanol • Propene • Dipropyl ether • 2o and 3o alcohols
Thiols (mercaptans) • Presence of –SH instead of –OH • Naming is the same and add –thiol to end without dropping –e • Ethanethiol • Skunks • Humans detect
Thiols • Lower b.p. because of weaker hydrogen bonding • Oxidized to disulfides: R-S-S-R • React with