文档介绍：Chapter 11 Reactions of Alcohols
Jo Blackburn
Richland College, Dallas, TX
Dallas munity College District
ã 2003, Prentice Hall
Organic Chemistry, 5th Edition L. G. Wade, Jr.
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Chapter 11
Types of Alcohol Reactions
Dehydration to alkene
Oxidation to aldehyde, ketone
Substitution to form alkyl halide
Reduction to alkane
Esterification
Tosylation
Williamson synthesis of ether =>
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Summary Table
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Oxidation States
Easy for anic salts
CrO42- reduced to Cr2O3
KMnO4 reduced to MnO2
Oxidation: loss of H2, gain of O, O2, or X2
Reduction: gain of H2 or H-, loss of O, O2, or X2
Neither: gain or loss of H+, H2O, HX =>
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Chapter 11
1º, 2º, 3º Carbons
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Chapter 11
Oxidation of 2° Alcohols
2° alcohol es a ketone
Reagent is Na2Cr2O7/H2SO4
Active reagent probably H2CrO4
Color change: orange to greenish-blue
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Chapter 11
Oxidation of 1° Alcohols
1° alcohol to aldehyde to carboxylic acid
Difficult to stop at aldehyde
Use pyridinium chlorochromate (PCC) to limit the oxidation.
PCC can also be used to oxidize 2° alcohols to ketones.
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3° Alcohols Don’t Oxidize
Cannot lose 2 H’s
Basis for chromic acid test
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Other Oxidation Reagents
Collins reagent: Cr2O3 in pyridine
Jones reagent: chromic acid in acetone
KMnO4 (strong oxidizer)
Nitric acid (strong oxidizer)
CuO, 300°C (industrial dehydrogenation)
Swern oxidation: dimethylsulfoxide, with oxalyl chloride and hindered base, oxidizes 2 alcohols to ketones and 1 alcohols to aldehydes. =>
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Biological Oxidation
Catalyzed by ADH, alcohol dehydrogenase.
Oxidizing agent is NAD+, nicotinamide adenine dinucleotide.
Ethanol oxidizes to acetaldehyde, then acetic acid, a normal metabolite.
Methanol oxidizes to formaldehyde, then formic acid, more toxic than methanol.
Ethylene glycol oxidizes to oxalic acid, toxic.
Treatment for poisoning is excess ethanol. =>
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