1. Chapter 13 Alcohols, Phenols, and Thiols
13.1
Alcohols, Phenols, and Thiols
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Publishing as Benjamin Cummings

2. Alcohols and Phenols An alcohol contains
A hydroxyl group (—OH) attached to a carbon chain.
A phenol contains
A hydroxyl group (—OH) attached to a benzene ring.
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3. Classification of Alcohols
Alcohols are classified
By the number of alkyl groups attached to the carbon bonded to the hydroxyl.
As primary (1°), secondary (2°), or tertiary (3°).
Primary (1º) Secondary (2º) Tertiary (3º) 1 group groups 3 groups H CH CH | | |
CH3—C—OH CH3—C—OH CH3—C—OH | | | H H CH3

4. Learning Check (P) primary, (S) secondary, or (T) tertiary. OH |
Classify each alcohol as
(P) primary, (S) secondary, or (T) tertiary. OH |
1. CH3—CH—CH2—CH3
2. CH3—CH2—CH2—OH
3. CH3—CH2—C—CH2—CH3
CH3

5. Solution | 1. CH3—CH—CH2—CH3 (S) secondaryOH |
1. CH3—CH—CH2—CH3 (S) secondary
2. CH3—CH2—CH2—OH (P) primary
3. CH3—CH2—C—CH2—CH3 (T) tertiary
CH3

6. Naming Alcohols The names of alcohols
In the IUPAC system replace -e of alkane name with -ol.
that are common names use the name of the alkyl group followed by alcohol.
Formula IUPAC Common Name
CH4 methane
CH3─OH methanol methyl alcohol
CH3─CH3 ethane
CH3─CH2─OH ethanol ethyl alcohol

7. More Names of Alcohols
In IUPAC names for longer carbon chains, the chain is
numbered from the end nearest the ─OH group.
CH3─CH2─CH2─OH propanol OH │
CH3─CH─CH2─CH butanol
CH OH
│ │
CH3─CH─CH2─CH2─CH─CH methyl-2-hexanol

8. Some Typical Alcohols | “rubbing alcohol” CH3—CH—CH3
2-propanol (isopropyl alcohol)
antifreeze HO—CH2—CH2—OH
1,2-ethanediol (ethylene glycol)
glycerol HO—CH2—CH—CH2—OH
1,2,3-propanetriol
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9. Learning Check Give the IUPAC name for each of the following:
1. CH3—CH2—CH2—CH2—OH
OH CH3
| |
2. CH3—CH—CH—CH2—CH3 3.

10. Solution OH CH3 | | 2. CH3—CH—CH—CH2—CH3 3-methyl-2-pentanol
1. CH3—CH2—CH2—CH2—OH 1-butanol
OH CH3
| |
2. CH3—CH—CH—CH2—CH methyl-2-pentanol
cyclopentanol

11. Learning Check Write the structure of the following: A. 3-pentanol
B. ethyl alcohol
C methylcyclohexanol

12. Solution Write the structure of the following: A. 3-pentanol OH |
CH3—CH2—CH—CH2—CH3
B. ethyl alcohol CH3 —CH2 —OH
C methylcyclohexanol

13. Naming Phenols To name a phenol with two substituents,
Assign C-1 to the carbon attached to the –OH.
Number the ring to give the lowest numbers.
Use prefixes o, m, and p for common names.
Phenol chlorophenol bromophenol
(m-chlorophenol) (p-bromophenol)

14. Phenols in Medicine Phenol
Is the IUPAC name for benzene with a hydroxyl group.
Is used in antiseptics and disinfectants.
phenol resorcinol hexylresorcinol

15. Derivatives of Phenol
Compounds of phenol are the active ingredients in the essential oils of cloves, vanilla, nutmeg, and mint.
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16. Learning Check Write the structure of each of the following:
A pentanol
B. ethyl alcohol
C. p-methylphenol

17. Solution Write the structure of each of the following:
A. 3-pentanol OH |
CH3—CH2—CH—CH2—CH3
B. ethyl alcohol CH3—CH2—OH
C. p-methylphenol

18. Thiols Thiols Are carbon compounds that contain a –SH group.
Are named in the IUPAC system by adding ­thiol to the alkane name of the longest carbon chain.

19. Naming Thiols
In thiols with long carbon chains, the chain is numbered to locate the –SH group.
CH3—CH2—CH2—SH 1-propanethiol SH |
CH3—CH—CH3 2-propanethiol

20. Thiols Thiols Often have strong odors. Are used to detect gas leaks.
Are found in onions, oysters, and garlic.
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21. Learning Check Draw the structure of each compound. A. 2-butanethiol
B. 2-methyl-1-butanol

22. Solution Draw the structure of each compound. A. 2-butanethiol SH |
CH3—CH—CH2—CH3
B. 2-methyl-1-butanol
CH3
HO—CH2—CH—CH2—CH3

23. Learning Check Name each of the following compounds: OH |
A. CH3—CH2 —CH—CH3
CH3
B. CH3—CH2—CH—CH2—CH2—OH
C. CH3—CH2—CH2—SH

24. Solution Name each of the following compounds: OH |
A. CH3—CH2 —CH—CH butanol
CH3
B. CH3—CH2—CH—CH2—CH2—OH
3-methyl-1-pentanol
C. CH3—CH2—CH2—SH
1-propanethiol

25. Chapter 13 Alcohols, Phenols, Ethers, and Thiols
13.2
Ethers
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26. Ethers Ethers Contain an ─O─ between two carbon groups.
That are simple are named by listing the alkyl names in alphabetical order followed by ether
CH3─O─CH3 CH3─CH2─O─CH3
dimethyl ether ethyl methyl ether

27. IUPAC Names for Ethers
In the IUPAC system, the shorter alkyl group and the oxygen are named as an alkoxy group attached to the longer alkane.
methoxy propane
CH3—O—CH2—CH2—CH3
Numbering the longer alkane gives
1-methoxypropane

28. Ethers as Anesthetics Anesthetics Inhibit pain signals to the brain.
Such as ethyl ether CH3─CH2─O─CH2─CH3 were used for over a century, but caused nausea and were flammable.
Developed by 1960s were nonflammable.
Cl F F Cl F H
│ │ │ │ │ │
H─C─C─O─C─H H─C─C─O─C─H
F F F H F H
Ethane(enflurane) Penthrane

29. MTBE Methyl tert-butyl ether CH3 │ CH3─O─C─CH3
Is one of the most produced organic chemicals.
Is a fuel additive
Is used to improve gasoline combustion.
Use is questioned since the discovery that MTBE has contaminated water supplies.

30. Learning Check Draw the structure of each compound. A. diethyl ether
B. ethyl methyl ether
C. 2-methoxybutane

31. Solution Draw the structure of each compound. A. diethyl ether
CH3—CH2—O—CH2—CH3
B. ethyl methyl ether CH3—CH2—O—CH3
C. 2-methoxybutane
O—CH3 |
CH3—CH—CH2—CH3

32. Cyclic Ethers A cyclic ether Contains an O atom in a carbon ring.
Is called a heterocyclic compound.
Typically has 5 (furan) or 6 atoms (pyran) in the ring.
furan tetrahydrofuran pyran ,4-dioxane

33. Dioxins Dioxins are A group of ethers that are highly toxic.
Formed during forest fires and as industrial by-products.
Often carcinogenic.
2,4,5-trichlorophenoxyacetic acid ,3,7,8-tetrachlorodibenzodioxin
(2,4,5-T; agent orange) (TTCC, “dioxin”)

34. Learning Check
Name each of the following: 1. 2.

35. Solution 1. methoxy cyclopentane (cyclopentyl methyl ether)
,4-dioxane

36. Chapter 13 Alcohols, Phenols, Ethers, and Thiols
13.3
Physical Properties of Alcohols,
Phenols, and Ethers
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37. Boiling Points of Alcohols
Contain a strongly electronegative O in the OH groups.
Form hydrogen bonds between alcohol molecules.
Have higher boiling points than alkanes and ethers of similar mass.
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38. Boiling Points of Ethers
Have an O atom, but no H is attached.
Cannot form hydrogen bonds between ether molecules.
Have boiling points similar to alkanes of similar mass.
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39. Solubility of Alcohols and Ethers in Water
Alcohols and ethers are more soluble in water than alkanes because the oxygen atom hydrogen bonds with water.
Alcohols with 1-4 C atoms are soluble, but alcohols with 5 or more C atoms are not.
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40. Comparing Solubility and Boiling Points
Compound Molar Boiling Soluble
Mass Point (°C) in Water?
Alkane CH3─CH2─CH No
Ether CH3─O─CH Yes
Alcohol CH3─CH2─OH Yes

41. Solubility of Phenol Phenol Is soluble in water.
Has a hydroxyl group that ionizes slightly (weak acid).
Is corrosive and irritating to the skin.
+ H2O H3O+

42. Learning Check Which compound would have the higher boiling
point? Explain.
ethyl methyl ether or 1-propanol

43. Solution 1-propanol would have the higher boiling point because
an alcohol can form hydrogen bonds, but the ether
cannot.

44. Learning Check Which compound would be more soluble in water? Explain.
ethanol or 2-pentanol

45. Solution Ethanol. An alcohol with two carbons in its carbon chain
is more soluble than one with 5 carbons. The longer
alkyl chain diminishes the effect of the –OH group.

46. Chapter 13 Alcohols, Phenols, Ethers, and Thiols
13.4
Reactions of Alcohols and Thiols
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47. Combustion of Alcohols
Combustion is the reaction of an alcohol
with O2 to produce CO2 and H2O.
2CH3OH + 3O CO H2O + Heat
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48. Dehydration of Alcohols
Dehydration of an alcohol occurs
When heated with an acid catalyst.
With the loss of —H and —OH from adjacent carbon atoms.
H OH
| | H+, heat
H—C—C—H H—C=C—H + H2O
| | | |
H H H H
alcohol alkene

49. Learning Check Write the equations for the reactions when
2-propanol undergoes:
1. combustion
2. dehydration

50. Solution OH │ CH3─CH─CH3 = 2-propanol = C3H8O 1. combustion
2C3H8O + 9O CO H2O
2. dehydration
│ H+
CH3─CH─CH CH3─CH=CH2 + H2O

51. Formation of Ethers
Ethers form when dehydration takes place at low temperature. H+
CH3—OH + HO—CH CH3—O—CH3 + H2O
two methanol dimethyl ether

52. Oxidation and Reduction
In the oxidation of an organic compound
There is an increase in the number of C—O bonds.
There is a loss of H.
In the reduction of an organic compound
There is an decrease in the number of C—O bonds.
There is a gain of H.

53. Oxidation and Reduction
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54. Oxidation of Primary (1) Alcohols
When a primary alcohol is oxidized [O],
One H is removed from the –OH.
Another H is removed from the carbon bonded to the OH.
An aldehyde is produced.
[O]
Primary alcohol Aldehyde
OH O
| [O] ||
CH3—C—H CH3—C—H + H2O | H
Ethanol Ethanal
(ethyl alcohol) (acetaldehyde)

55. Oxidation of Secondary (2) Alcohols
When a secondary alcohol is oxidized [O],
One H is removed from the –OH.
Another H is removed from the carbon bonded to the OH.
A ketone is produced.
[O]
secondary alcohol ketone
OH O
│ [O] ║
CH3—C—CH CH3—C—CH3 + H2O │ H
2-propanol (isopropyl alcohol) propanone(dimethyl ketone,
“acetone”)

56. Oxidation of Tertiary (3)Alcohols
Tertiary alcohols do not readily oxidize [O]
Tertiary alcohol no reaction OH
│ [O]
CH3─C─CH3 no product │
CH no H on the C-OH to oxidize
2-methyl-2-propanol

57. Learning Check Select the compound that would result for each reaction
of CH3—CH2—CH2—OH.
O ||
1) CH3—CH=CH ) CO2 + H2O ) CH3—CH2—C—H
A. H+, heat
B. [O]
C. O2, heat

58. Solution CH3—CH2—CH2—OH A. H+, heat 1) CH3—CH=CH2 O ||
B. [O] 3) CH3—CH2—C—H
C. O2, heat 2) CO2 + H2O

59. Oxidation of Ethanol in the Body
Ethanol is oxidized by enzymes in the liver.
Aldehyde product impairs coordination.
O O
║ ║
CH3─CH2─OH CH3─C─H CH3─C─OH
ethyl alcohol acetaldehyde acetic acid
2CO2 + H2O

60. Ethanol CH3─CH2─OH Ethanol Acts as a depressant.
Kills or disables more people than any other drug.
Is metabolized at a rate of mg/dL per hour by a social drinker.
Is metabolized at a rate of 30 mg/dL per hour by an alcoholic.
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61. Effect of Alcohol on the Body
TABLE 13.2
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62. Learning Check OH │ [O] CH3—CH—CH2—CH3 O ║
Select the product for the oxidation of OH
│ [O]
CH3—CH—CH2—CH3
O ║
1) CH3—CH=CH—CH ) CH3—C—CH2 —CH3 │
3) CO2 + H2O ) CH3—CH—CH2—CH3

63. Solution OH │ [O] CH3—CH—CH2—CH3 O ║ 2) CH3—C—CH2—CH3
Select the product for the oxidation of OH
│ [O]
CH3—CH—CH2—CH3
O ║
2) CH3—C—CH2—CH3

64. Oxidation of Thiols When thiols undergo oxidation,
An H atom is lost from each of two –SH groups.
The product is a disulfide.
[O]
CH3—SH + HS—CH CH3—S—S—CH3 + H2O