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Transcript
Alcohols, Phenols, and Ethers
Chapter 14
Problem-Set Solutions
14.1
a.
b.
c.
d.
Oxygen has 6 valence electrons and so forms 2 covalent bonds.
Hydrogen has 1 valence electron and forms 1 covalent bond to complete its “octet” of 2.
Carbon has 4 valence electrons and so forms 4 covalent bonds.
A halogen atom has 7 valence electrons and so forms 1 covalent bond.
14.2
a. incorrect
14.3
The generalized formula for an alcohol is R–OH, where R is an alkyl group with a saturated
carbon attached to the OH group.
14.4
hydroxyl group
14.5
Alcohols may be viewed as being alkyl derivatives of water in which a hydrogen atom has
been replaced by an alkyl group.
14.6
R–OH versus R–H
14.7
To name an alcohol by the IUPAC rules, find the longest carbon chain to which the hydroxyl
group is attached, number the chain starting at the end nearest the hydroxyl group, and name
and locate any other substituents present. Use the suffix –ol.
a. 2-pentanol
b. ethanol
c. 3-methyl-2-butanol
d. 2-ethyl-1-pentanol
e. 2-butanol
f. 3,3-dimethyl-1-butanol
14.8
a. 3-pentanol
d. 2,3-dimethyl-1-butanol
14.9
To name an alcohol by the IUPAC rules, find the longest carbon chain to which the hydroxyl
group is attached, number the chain starting at the end nearest the hydroxyl group, and name
and locate any other substituents present. Use the suffix –ol.
a. 1-hexanol
b. 3-hexanol
c. 5,6-dimethyl-2-heptanol
d. 2-methyl-3-pentanol
14.10 a. 2-heptanol
c. 3-ethyl-1-hexanol
462
b. correct
c. correct
b. 2-methyl-3-pentanol
e. 2-methyl-2-butanol
d. incorrect
c. 4-ethyl-1-heptanol
f. 4,4,5-trimethyl-3-heptanol
b. 1-butanol
d. 3-methyl-4-heptanol
Copyright © Houghton Mifflin Company. All rights reserved.
463
Problem-Set Solutions Chapter 14
14.11 In an alcohol name, the number before the parent chain designates the position of the –OH
group. The positions of the substituents are numbered relative to the –OH group.
a. CH3 CH2 CH
CH2 CH3
OH
c. CH2 CH
OH
b. CH3 CH2 C
CH3
d. CH3 CH
CH3
C
CH2 CH2 CH3
OH
CH2 CH
OH
OH
H3C
CH2 CH3
CH3
OH
f.
CH3
CH3
e.
CH3
CH3
14.12 a. CH3 CH
CH2 CH2
CH2 CH2 CH3
b. CH2
OH
OH
C
CH2
CH2 CH2 CH3
CH
CH2 CH3
CH3
OH
c. CH3 C
CH2 CH2
CH2 CH2 CH3
d. CH3
CH
OH
CH3
CH2
CH3
e. CH2 CH2 CH
CH3
OH
f.
OH
CH3
CH3
14.13 Common names exist for alcohols with simple alkyl groups. The word alcohol, as a separate
word, is placed after the name of the alkyl group.
a.
CH3 CH2 CH2 CH2 CH2 OH
1-pentanol
c. CH3 CH
CH2 OH
CH3
2-methyl-1-propanol
Copyright © Houghton Mifflin Company. All rights reserved.
b. CH3 CH2 CH2 OH
1-propanol
d. CH3 CH2 CH
CH3
2-butanol
OH
464
Problem-Set Solutions Chapter 14
14.14 a. CH3 CH2 CH2 CH2 OH
b. CH3 CH2 CH2 CH2
CH2 CH2 OH
1-hexanol
1-butanol
CH3
d. CH3
c. CH3 CH OH
C
OH
CH3
CH3
2-methyl-2-propanol
2-propanol
14.15 Polyhydroxy alcohols (more than one hydroxyl group) can be named with a slight
modification: a compound with two hydroxyl groups is named a diol, one with three hydroxyl
groups is a triol.
a. 1,2-propanediol
b. 1,4-pentanediol
c. 1,3-pentanediol
d. 3-methyl-1,2,4-butanetriol
14.16 a. 2-methyl-1,3-propanediol
c. 2,3-pentanediol
b. 1,2-butanediol
d. 1,2,3-butanetriol
14.17 In naming cyclic alcohols the carbon to which the –OH group is attached is assigned the
number 1. The substituents on the ring are numbered relative to the –OH group. However, the
number 1 (designating the –OH group) is not included in the name.
a. cyclohexanol
b. trans-3-chlorocyclohexanol
c. cis-2-methylcyclohexanol
d. 1-methylcyclobutanol
14.18 a. trans-2-methylcyclohexanol
c. cis-3-bromocyclohexanol
b. cyclopentanol
d. cis-2-methylcyclopropanol
14.19 In the naming of alcohols with unsaturated carbon chains, the longest chain must contain both
the carbon atom to which the hydroxyl group is attached and also the carbon atoms which are
unsaturated. The chain is numbered from the end that gives the lowest number to the carbon
to which the hydroxyl group is attached. Two endings are needed: one for the double or triple
bond and one for the –OH group. Unsaturated alcohols are named as alkenols or alkynols.
a. CH3 CH
CH2 CH
CH2
b.
HC
C
CH
OH
c.
CH3 CH
OH
CH2 CH3
OH
C
CH2
HO
CH2
d.
CH3
CH3
C
C
H
H
.
14.20 a. H2C
CH
CH
CH2 CH3
b. CH2
CH2
HO CH2
OH
CH
CH3
CH
CH
OH
OH
c. CH2
C
CH2
CH2
H
C
d.
H
C
CH3
.
Copyright © Houghton Mifflin Company. All rights reserved.
465
Problem-Set Solutions Chapter 14
14.21 a. CH2 CH
OH
CH3
For the incorrect name, the wrong parent chain was
chosen. The correct name is 2-methyl-1-butanol.
CH2 CH2
For the incorrect name, the parent chain was numbered
from the wrong end. The correct name is 1,3-butanediol.
CH2
CH3
b.
CH3 CH
OH
OH
c. CH3 CH
CH
CH3
CH3 OH
HO
d.
OH
14.22 a. CH3 CH
CH
OH
For the incorrect name, the parent chain was
numbered from the wrong end. The correct name is
3-methyl-2-butanol.
When there are two possible ways to number the
substituents on a ring, choose the way that gives the
lowest possible total number. The correct name is
1,3-cyclopentanediol.
b. CH3 CH2 CH
CH3
OH
CH2
CH
CH3
OH
CH3
3-methyl-2-pentanol
2,3-pentanediol
CH3
c. CH3
CH2
C
CH3
d. CH3
CH3
OH
C
CH2
CH2
CH3
OH
2-methyl-2-butanol
2-methyl-2-pentanol
14.23 a. No, this is not a constitutional isomer of 1-hexanol; it has a different molecular formula.
(This is 1-pentanol.)
b. Yes, this is a constitutional isomer of 1-hexanol; the position of the functional group (OH)
has changed. (This is 3-hexanol.)
c. Yes, this is a constitutional isomer of 1-hexanol; the carbon-chain arrangement has
changed. (This is 4-methyl-2-pentanol.)
d. Yes, this is a constitutional isomer of 1-hexanol; the position of the functional group (OH)
has changed. (This is the same compound as the one in part b., 3-hexanol.)
14.24 a. no
b. yes
c. yes
d. no
14.25 Since the carbon chain is unbranched, there are four possible positions for the –OH group.
1-heptanol, 2-heptanol, 3-heptanol, and 4-heptanol.
14.26 1-octanol, 2-octanol, 3-octanol, 4-octanol
Copyright © Houghton Mifflin Company. All rights reserved.
466
Problem-Set Solutions Chapter 14
14.27 For the alcohol 2-methyl-x-pentanol, the possible values of x that will give a correct IUPAC
name are x = 1, 2, or 3. If x had a higher value, the alcohol would be numbered from the
wrong end of the chain (2-methyl-4-pentanol is an incorrect name for 4-methyl-2-pentanol,
and 2-methyl-5-pentanol is an incorrect name for 4-methyl-1-pentanol).
14.28 x = 1, 2, or 3
14.29 a. Absolute alcohol is 100% ethyl alcohol, with all traces of water removed.
b. Grain alcohol is ethyl alcohol; ethyl alcohol can be synthesized from grains such as corn,
rice, and barley.
c. Rubbing alcohol is 70% isopropyl alcohol; because of its high evaporation rate, it is used
for alcohol rubs combating high body temperatures.
d. Drinking alcohol is ethyl alcohol; it is the alcohol produced by yeast fermentation of
sugars, and it is present in all alcoholic beverages.
14.30 a.
b.
c.
d.
methanol
ethanol with toxic agents added to make it undrinkable
35% solution of ethanol
drinking alcohol (ethanol)
14.31 a.
b.
c.
d.
Glycerol is a thick liquid that has the consistency of honey.
Ethanol is often produced by a fermentation process.
Methanol is used as a race car fuel.
Methanol can be industrially produced from CO and H2.
14.32 a. isopropyl alcohol
b. ethylene glycol
c. ethanol
d. glycerol
14.33 Alcohols can form hydrogen bonds with one another (see Figure 14.10). Alkane molecules do
not form hydrogen bonds.
14.34 Alcohols can hydrogen-bond to water; alkanes cannot.
14.35 a. 1-Heptanol has a higher boiling point than 1-butanol because boiling point increases as the
length of the carbon chain increases.
b. 1-Propanol has a higher boiling point than butane; 1-propanol forms hydrogen bonds
between molecules.
c. 1,2-Ethanediol has a higher boiling point than ethanol; because of increased hydrogen
bonding, alcohols with multiple –OH groups have higher boiling points than their
monohydroxy counterparts.
14.36 a. 1-octanol
b. 1-butanol
c. 1,3-propanediol
14.37 a. 1-Butanol is more soluble than butane because alcohol molecules can form hydrogen bonds
with water molecules.
b. 1-Pentanol is more water-soluble than 1-octanol; as the carbon-chain (nonpolar) increases
in length, solubility in water (polar) decreases.
c. 1,2-Butanediol is more water-soluble than 1-butanol; increased hydrogen bonding makes an
alcohol with two –OH groups more soluble than its counterpart with one –OH group.
14.38 a. 1-butanol
b. 1-propanol
c. 1,2,3-propanetriol
Copyright © Houghton Mifflin Company. All rights reserved.
467
Problem-Set Solutions Chapter 14
14.39 a. Three hydrogen bonds can form between ethanol molecules (see Figure 14.10).
b. Three hydrogen bonds can form between ethanol molecules and water molecules
(see Figure 14.11).
c. Three hydrogen bonds can form between methanol molecules (see Figure 14.10).
d. Three hydrogen bonds can form between 1-propanol molecules (see Figure 14.10).
14.40 a. 3
b. 3
c. 3
d. 3
14.41 Two general methods of preparing alcohols are: 1) the hydration of alkenes, in which a
molecule of water is added to a double bond in the presence of a catalyst (sulfuric acid), and
2) the addition of H2 to a carbon-oxygen double bond (a carbonyl group) in the presence of a
catalyst.
a.
CH3 CH2
b. CH3 CH2 CH2
OH
OH
OH
OH
c. CH3 CH2 C
d. CH3 CH2 CH
CH3
CH2 CH3
CH3
14.42
a. CH3
CH
CH2 CH3
b. CH3
CH2
OH
d. CH3
CH
CH
c. CH3
CH3
OH
CH
CH2 CH3
and
CH3 OH
CH3
CH2
OH
CH CH2
CH3
CH
CH3
OH
14.43 Alcohols are classified by the number of carbons bonded to the hydroxyl-bearing carbon atom:
in a primary alcohol, the hydroxyl-bearing carbon atom is bonded to one other carbon atom; in
a secondary alcohol, it is bonded to two other carbon atoms; and in a tertiary alcohol, it is
bonded to three other carbon atoms.
a. 2-Pentanol is secondary alcohol.
b. Ethanol is a primary alcohol.
c. 3-Methyl-2-butanol is a secondary alcohol. d. 2-Ethyl-1-pentanol is a primary alcohol.
e. 2-Butanol is a secondary alcohol.
f. 3,3-Dimethyl-1-butanol is a primary alcohol.
14.44 a. secondary
d. primary
b. secondary
e. tertiary
c. primary
f. secondary
14.45 In the dehydration of an alcohol, the components of a water molecule (H and OH) are removed
from a single molecule or from two molecules. Sulfuric acid is the catalyst. Notice that in parts
a. and c. the starting material is the same, but the temperature differs. The same product is
formed at both 140oC as at 180oC.
.
a. CH2
CH
CH3
b. CH3 C
CH2
CH3
c. CH2
.
CH
.
CH3
Copyright © Houghton Mifflin Company. All rights reserved.
d. CH3 CH2 CH2 O
.
CH2 CH2 CH3
468
Problem-Set Solutions Chapter 14
b. CH3 C
.
14.46 a. CH3 CH
.
CH2 O
CH2 CH CH3
CH3
CH2
CH3
CH3
.
.
c. CH3
CH
CH
d. CH3
CH3
CH
CH
CH3
14.47 In the dehydration of an alcohol, the components of a water molecule (H and OH) are removed
from a single molecule or from two molecules. Apply Zaitsev’s rule in parts a. and b.: the
major product in an intramolecular alcohol dehydration reaction is the alkene that has the
greatest number of alkyl groups attached to the carbon atoms of the double bond.
a. CH3 CH CH CH3
b. CH3 CH2 CH2
OH CH3
c.
or
CH3 CH OH
OH
CH3
d. CH3 CH CH2 OH
.
CH3 CH2 OH
.
CH3
14.48 a. CH2
CH
b. CH3 CH2
CH2 CH3
CH2 CH2
OH
OH CH3
c. CH3
OH
d. CH3
CH2
OH
14.49 Primary and secondary alcohols may be oxidized in the presence of a mild oxidizing agent. A
primary alcohol produces an aldehyde that is often further oxidized to a carboxylic acid. A
secondary alcohol produces a ketone.
R
O
H
C
H
O
O
R
C
H
O
O
R
C
OH
H
1o
R
Aldehyde
Alcohol
O
H
C
R
O
Carboxlic acid
O
R
C
R
H
Ketone
2o Alcohol
.
.
a. CH3 CH2 CH CH3
b. CH3 CH2 CH2 OH
.
OH
.
c.
CH3 CH2 CH2 OH
.
d.
CH2 OH
Copyright © Houghton Mifflin Company. All rights reserved.
469
Problem-Set Solutions Chapter 14
14.50 a. CH3 CH
CH3
b.
CH2 OH
CH CH CH3
CH3 OH
CH3
c. CH3
CH
d.
CH2 CH2 OH
CH3
CH2
OH
14.51 Alcohols undergo several types of reaction. Parts a., d., and f. of this problem are halogenation
reactions in which a halogen atom is substituted for the hydroxyl group. Part c. is the mild
oxidation of a secondary alcohol. In part b., a water molecule is removed (dehydration
reaction) within the molecule (180oC). Remember to use Zaitsev’s rule. In part e., also a
dehydration reaction but at a lower temperature, a water molecule is removed from two
alcohol molecules to produce an ether (140oC).
a.
.
CH3 CH2 CH2 Cl
b.
.
CH3
O
c. CH3 C
d. CH3 CH2 CH
CH2 CH3
CH2 CH3
Cl
.
.
e. CH3 CH2
O
f. CH2 CH2
CH2 CH3
.
Cl
14.52 a. CH3 CH2 CH2 Br
.
Cl
.
CH3
b.
.
Cl
.
c. CH3 CH2 CH2 CH2 O CH2 CH2 CH2 CH3
.
O
.
d.
CH3 CH2
C CH2
CH3
e. CH3 CH
CH2
f.
CH2
CH2
Cl
Cl
14.53 Polymeric alcohols have structures similar to those of substituted polyethylenes.
CH
CH
OH
OH n
Copyright © Houghton Mifflin Company. All rights reserved.
470
Problem-Set Solutions Chapter 14
14.54
CH2
CH
OH
n
14.55 In a phenol, the –OH group is attached to a carbon atom that is part of an aromatic ring, as in
the first structure. In the second structure, the –OH group is attached to an alkyl group, so it is
not a phenol.
14.56 The ring to which the –OH group is attached must be a benzene ring.
14.57 In naming phenols, the parent name is phenol; substituents are numbered beginning with the
–OH group and proceeds in the direction that gives the lower number to the next carbon atom
bearing a substituent. The –OH group is not specified in the name because it is 1 by definition.
a. 3-ethylphenol
b. 2-chlorophenol
c. o-cresol
d. hydroquinone
e. 2-bromophenol
f. 2-bromo-3-ethylphenol
14.58 a. 4-propylphenol
c. p-cresol
e. 3-chlorophenol
b. catechol
d. 2-bromophenol
f. 4-chloro-2-isopropylphenol
14.59 The positions of the substituents are relative to the –OH group (carbon 1). Methylphenols are
called cresols. Each of the three hydroxyphenols has a different name: resorcinol is the
meta-hydroxyphenol.
OH
OH
CH2 CH3
b.
a.
Cl
OH
OH
Br
c.
d.
CH3
Br
.
OH
OH
H3C
H2C
CH2 CH3
f.
e.
OH
CH3
Copyright © Houghton Mifflin Company. All rights reserved.
471
Problem-Set Solutions Chapter 14
OH
OH
14.60 a.
b.
Br
CH2 CH3
OH
OH
CH3
d.
c.
OH
OH
OH
OH
e.
Cl
Cl
f.
14.61 An antiseptic kills microorganisms on living tissue; a disinfectant kills microorganisms on
inanimate objects.
14.62 An antioxidant is a substance that is more readily oxidized than some other substances; the
antioxidant is oxidized first, keeping the other substances from becoming oxidized.
14.63 Phenols are weak acids in water solution, and like other weak acids, they ionize in water to
form the hydronium ion and a negative ion (the phenoxide ion).
_
O
OH
+ H2O
+ H3O +
14.64 Phenols are less acidic than most inorganic weak acids.
14.65 In an ether, an oxygen atom is bonded to two carbon atoms by single bonds.
a. Yes, this is an ether.
b. No, this is not an ether; it is an alcohol.
c. Yes, this is an ether.
d. Yes, this is an ether.
14.66 a.
b.
c.
d.
ether and alcohol
two ethers, one with an alkyl and an aromatic group and the other with two aromatic groups
phenol and ether
two ethers, one with two alkyl groups and the other with two aromatic groups
Copyright © Houghton Mifflin Company. All rights reserved.
472
Problem-Set Solutions Chapter 14
14.67 In the IUPAC system, ethers are named as substituted hydrocarbons. The longest carbon chain
is the base name. Change the –yl ending of the other alkyl group to –oxy, and place the alkoxy
name, with a locator number, in front of the base chain name.
a. 1-methoxypropane
b. 1-ethoxypropane
c. 2-methoxypropane
d. methoxybenzene
e. cyclohexoxycyclohexane
f. ethoxycyclobutane
14.68 a. ethoxyethane
c. 2-ethoxybutane
e. propoxycyclohexane
b. 2-methoxypropane
d. phenoxybenzene
f. ethoxybenzene
14.69 The common names for ethers use the form: alkyl alkyl ether or dialkyl ether. Two different
alkyl groups are written in alphabetical order.
a. methyl propyl ether
b. ethyl propyl ether
c. isopropyl methyl ether
d. methyl phenyl ether
e. dicyclohexyl ether
f. cyclobutyl ethyl ether
14.70 a. diethyl ether
c. ethyl sec-butyl ethers
e. cyclohexyl propyl ether
b. isopropyl methyl ether
d. diphenyl ether
f. ethyl phenyl ether
14.71 In the IUPAC system, ethers are named as substituted hydrocarbons. The longest carbon chain
is the base name. Change the –yl ending of the other alkyl group to –oxy, and place the alkoxy
name, with a locator number, in front of the base chain name.
a. 1-methoxypentane
b. 1-ethoxy-2-methylpropane
c. 2-ethoxybutane
d. 2-methoxybutane
14.72 a. 1-ethoxypropane
c. 1-propoxybutane
b. 1-methoxy-2-methylpropane
d. 1-methoxy-1,1-dimethylethane
14.73 The common names for ethers use the form: alkyl alkyl ether or dialkyl ether.
a. CH3 CH
O CH2 CH2 CH3
CH3
O
CH3
b. CH3 CH2
d.
CH3 CH
O
O
CH2 CH2 CH3
CH2 CH3
c.
CH3
O
e.
CH2 CH3
CH3
f.
CH3 O
CH2 C
CH3
CH3
Copyright © Houghton Mifflin Company. All rights reserved.
473
Problem-Set Solutions Chapter 14
O
CH3
.
14.74 a. CH3 CH2 CH2 CH2 O CH3
b.
.
c.
O CH2
CH2 CH3
d. CH3 CH2
CH
O
O
CH2
CH2
CH2 CH2 CH3
CH2
CH3
CH3
f. CH3
e.
O
CH
CH
CH2
CH2 CH3
CH3 O
CH3
CH3
14.75 Constitutional isomers have the same molecular formulas, but different bonding arrangements
between atoms. Ethyl propyl ether has a molecular formula of C5H12O.
a. No, this is not a constitutional isomer of ethyl propyl ether; the molecular formula is
C6H14O.
b. No, this is not a constitutional isomer of ethyl propyl ether; the molecular formula is
C6H14O.
c. Yes, this is a constitutional isomer of ethyl propyl ether; the molecular formula is
C5H12O, and the name is sec-butyl methyl ether.
d. No, this is not a constitutional isomer of ethyl propyl ether; the molecular formula is
C6H14O.
14.76 a. no
b. yes
c. no
Copyright © Houghton Mifflin Company. All rights reserved.
d. no
474
Problem-Set Solutions Chapter 14
14.77 The easiest way to find the common names for the five ethers that are constitutional isomers of
ethyl propyl ether is to draw the isomers and then name them.
O
O
O
butyl methyl ether
isobutyl methyl ether
sec-butyl methyl ether
O
tert-butyl methyl ether
O
ethyl isopropyl ether
14.78 ethyl propyl ether, ethyl isopropyl ether, sec-butyl methyl ether, tert-butyl methyl ether,
isobutyl methyl ether
14.79 Functional group isomers are constitutional isomers that contain different functional groups.
a.
CH3 O CH2 CH2 CH3
CH3 O
CH CH3
CH3
CH3 CH2 O CH2 CH3
b.
CH3 CH2 CH2 CH2 OH
CH3 CH2
CH OH
CH3
CH3
CH3
CH
CH2 OH
CH3
a.
OH
CH3
CH3
14.80
C
CH3 O CH2 CH2 CH3
CH3 O
CH CH3
CH3
CH3 CH2 O CH2 CH3
b.
CH3 CH2 CH2 CH2 OH
CH3 CH2
CH OH
CH3
CH3
CH3
CH
CH3
CH2 OH
CH3
C
OH
CH3
Copyright © Houghton Mifflin Company. All rights reserved.
475
Problem-Set Solutions Chapter 14
14.81 The values of x for which x-methoxy-3-methylpentane is a correct IUPAC name are:
x = 1, 2, or 3. The names that include x = 4 or 5 would be incorrect because the numbering
would be from the wrong end of the carbon chain.
14.82 x = 1, 2, or 3
14.83 There is no hydrogen bonding between molecules of dimethyl ether (disruptive forces are
greater than cohesive forces); there is hydrogen bonding between molecules of ethyl alcohol
(cohesive forces are of about the same magnitude as disruptive forces).
14.84 Alcohols are more soluble because of hydrogen bonding.
14.85 The two chemical hazards associated with ether use are flammability and peroxide formation.
14.86 a. Ethers are much less reactive than alcohols.
b. Ethers are slightly less reactive than alkanes.
14.87 Ether molecules cannot form hydrogen bonds with one another because there are no oxygenhydrogen bonds in ethers.
14.88 two
14.89 In cyclic ethers, the ether functional group is part of a ring system.
a. This is a noncyclic ether; the ether functional group is not included in the ring.
b. This is a noncyclic ether; the ether functional group is not included in the ring.
c. This is a cyclic ether; the functional group is part of the ring system.
d. This is a cyclic ether; the functional group is part of the ring system.
e. This is a noncyclic ether; the ether functional group is not included in the ring.
f. This is a nonether; it is an alcohol.
14.90 a. noncyclic ether
d. nonether
b. noncyclic ether
e. noncyclic ether
c. cyclic ether
f. cyclic ether
14.91 A thioalcohol has the general formula R–S–H where R is an alkyl group; an alcohol has the
general formula R–O–H.
14.92 R–S–R versus R–O–R
14.93 In the IUPAC system, the names of thiols are similar to those of alcohols except that –ol has
been replaced by –thiol.
b. CH3 CH
.
a. CH3 SH
CH3
.
SH
c. CH2 CH2 CH2 CH3
SH
e.
d. CH2 CH2 CH
SH
SH
Copyright © Houghton Mifflin Company. All rights reserved.
CH3
f. CH2 CH2
SH
SH
CH2 CH3
476
Problem-Set Solutions Chapter 14
14.94 a.
CH2
b. CH3 CH2 SH
CH2 CH3
SH
CH3
c. CH2 CH2
SH
CH
CH2 CH3
d. CH3 CH2
C
CH2
CH3
SH
SH
SH
CH3
e.
CH3
f. CH2 C
SH
CH2
CH2 CH2 CH3
CH3
14.95 In writing common names for thiols, the name of the alkyl group (as a separate word) precedes
the word mercaptan. The structures of thiols are similar to those of alcohols, except the
oxygen atom is replaced by a sulfur atom.
a. methyl mercaptan
b. propyl mercaptan
c. sec-butyl mercaptan
d. isobutyl mercaptan
14.96 a. ethyl mercaptan
c. butyl mercaptan
b. isopropyl mercaptan
d. tert-butyl mercaptan
14.97 The oxidation of an alcohol produces aldehydes (which may be further oxidized to carboxylic
acids) and ketones; the oxidation of a thiol produces disulfides.
14.98 a. CH3–CH2–S–S–CH2–CH3
b. CH3–CH2–SH
14.99 In the IUPAC system, the names of thiols are similar to those of alcohols except that –ol has
been replaced by –thiol. In writing common names for thiols, the name of the alkyl group (as a
separate word) precedes the word mercaptan.
a. methylthioethane, ethyl methyl sulfide
b. 2-methylthiopropane, isopropyl methyl sulfide
c. methylthiocyclohexane, cyclohexyl methyl sulfide
d. cyclohexylthiocyclohexane, dicyclohexyl sulfide
e. 3-(methylthio)-1-propene, allyl methyl sulfide
f. 2-methylthiobutane, sec-butyl methyl sulfide
14.100 a.
b.
c.
d.
e.
f.
ethylthioethane; diethyl sulfide
2-ethylthiopropane; ethyl isopropyl sulfide
methylthiocyclopentane; cyclopentyl methyl sulfide
cyclopentylthiocyclohexane; cyclohexyl cyclopentyl sulfide
1-(ethylthio)-2-propene; allyl ethyl sulfide
2-methylthiopropane; isopropyl methyl sulfide
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477
Problem-Set Solutions Chapter 14
14.101 To name an alcohol by the IUPAC rules, find the longest carbon chain to which the hydroxyl
group is attached, number the chain starting at the end nearest the hydroxyl group, and name
and locate any other substituents present. Use the suffix –ol. Ethers are named as substituted
hydrocarbons. The longest carbon chain is the base name. Change the –yl ending of the other
alkyl group to –oxy, and place the alkoxy name, with a locator number, in front of the base
chain name.
a. 2-hexanol
b. 3-pentanol
c. 3-phenoxy-1-propene
d. 2-methyl-1-propanol
e. 2-methyl-2-propanol
f. ethoxyethane
14.102 CH2 CH2 CH2 CH2 CH3
CH3 CH CH2 CH2 CH3
OH
OH
CH3 CH2 CH CH2 CH3
OH
CH2 CH2
OH
CH CH3
CH3
CH3 CH
OH
CH CH3
CH3
CH3 CH2 CH2 CH2 O CH3
CH2
CH CH2 CH3
OH CH3
CH3
CH3
C
CH2 CH3
OH
CH3
CH2
C
OH
CH3
CH3
CH3 CH
CH2 O CH3
CH3
CH3 CH2
CH O CH3
CH3
CH3
CH3 C
O CH3
CH3
CH3 CH2 CH2 O CH2 CH3
CH3 CH O CH2 CH3
CH3
14.103 The dehydration of 1-pentanol yields only 1-pentene. Dehydration of 2-pentanol would yield
a mixture of alkenes, and the dehydration of 3-pentanol would yield 2-pentene.
14.104 CH3–O–CH3; CH3–CH2–CH2–O–CH2–CH2–CH3; and CH3–O–CH2–CH2–CH3
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478
Problem-Set Solutions Chapter 14
14.105 a. This is a disulfide; two sulfur atoms are bonded together, and each is bonded to a carbon
atom (R–S–S–R).
b. This is a thiol (thioalcohol); a sulfur atom is bonded to a carbon atom and to a hydrogen
atom (R–SH).
c. This is an alcohol; the general formula is R–OH.
d. This a peroxide (R–O–O–R).
e. This is both an alcohol and a thiol (thioalcohol).
f. This is both an ether and a sulfide (thioether).
14.106 a. 1,2-ethanedithiol
d. 1,2-dimethoxyethane
b. 3-methoxy-1-propanol
e. methylthioethane
c. 1-propanol
f. 1-ethylthio-2-methoxyethane
14.107 The correct IUPAC name is d. 3-methyl-2-butanol.
14.108 c
14.109 The correct answer is b. The organic product formed by the oxidation of a secondary alcohol
is a ketone.
14.110 c
14.111 Answer b. is incorrect. Alcohol solubility in water increases (rather than decreases) as the
number of –OH groups present increases.
14.112 a
14.113 The correct answer is a. Simple ethers may be viewed as derivatives of water in which both
hydrogen atoms have been replaced with alkyl groups.
14.114 d
14.115 Answer a. is correct. A characteristic property of thiols is extremely strong odors.
14.116 d
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