Transcript ch12 - Organic Compounds with Oxygen and Sulfur

Chapter 12 Organic Compounds with
Oxygen and Sulfur
1
12.1
Alcohols, Phenols, Thiols,
and Ethers
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition
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Alcohols
2
An alcohol contains a hydroxyl group (–OH) that replaces a
hydrogen atom in a hydrocarbon.
A phenol contains a hydroxyl group (–OH) attached to a
benzene ring.
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Naming Alcohols
3
The names of alcohols
• in the IUPAC system replace the -e with -ol
• with common names use the name of the alkyl group
followed by alcohol
Formula
IUPAC
CH4
methane
CH3─OH
methanol
CH3─CH3
ethane
CH3─CH2─OH
ethanol
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Common Name
methyl alcohol
ethyl alcohol
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Naming Alcohols
4
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition
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Naming of Alcohols
5
Step 1 Name the longest carbon chain with the –OH group.
Name an aromatic alcohol as a phenol.
CH3CH2CH2OH
propanol
OH
CH3CHCH2CH3
CH3
butanol
OH
CH3CHCH2CH2CHCH3
6
5 4
3
2
1
hexanol
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Naming of Alcohols
6
Step 2
Number the chain starting at the end closer to the
–OH.
CH3CH2CH2OH
1-propanol
OH
CH3CHCH2CH3
CH3
2-butanol
OH
CH3CHCH2CH2CHCH3
6
5
4
3
2 1
2-hexanol
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Naming of Alcohols
7
Step 3
Give the location and name of each substituent
relative to the –OH group.
CH3CH2CH2OH
1-propanol
OH
CH3CHCH2CH3
CH3
2-butanol
OH
CH3CHCH2CH2CHCH3
6
5 4
3
2
1
5-methyl-2-hexanol
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Some Typical Alcohols
8
OH
|
“Rubbing alcohol” CH3—CH—CH3
2-propanol (isopropyl alcohol)
Antifreeze HO—CH2—CH2—OH
1,2-ethanediol (ethylene glycol)
OH
|
Glycerol
HO—CH2—CH—CH2—OH
1,2,3-propanetriol
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Learning Check
9
Name the following compounds:
1. CH3—CH2—CH2—CH2—OH
2.
OH CH3
|
|
CH3—CH—CH—CH2—CH3
OH
3.
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Solution
10
Step 1 Name the longest carbon chain with the –OH group.
Name an aromatic alcohol as a phenol.
1. CH3—CH2—CH2—CH2—OH
butanol
OH CH3
|
|
2. CH3—CH—CH—CH2—CH3
pentanol
OH
3.
cyclopentanol
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Solution
11
Step 2
Number the chain starting at the end closer to the
–OH.
1. CH3—CH2—CH2—CH2—OH
1-butanol
OH CH3
|
|
2. CH3—CH—CH—CH2—CH3
2-pentanol
OH
3.
cyclopentanol
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Solution
12
Step 3
Give the location and name of each substituent
relative to the –OH group.
1. CH3—CH2—CH2—CH2—OH
1-butanol
OH CH3
|
|
2. CH3—CH—CH—CH2—CH3
3-methyl-2-pentanol
OH
3.
cyclopentanol
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Phenols in Medicine
13
Phenol is
• the IUPAC name for benzene with a hydroxyl group
• used in antiseptics and disinfectants
OH
OH
OH
OH
OH
CH2CH2CH2CH2CH2CH3
Phenol
Resorcinol
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4-Hexylresorcinol
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Derivatives of Phenol
14
Compounds of phenol are the active ingredients in the essential
oils of cloves, vanilla, nutmeg, and mint.
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Naming Phenols
15
Step 1 Name the longest carbon chain with the –OH group.
Name an aromatic alcohol as a phenol.
OH
OH
Cl
Br
phenol
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phenol
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Naming Phenols
16
Step 2
Number the chain starting at the end closer to the
–OH.
OH
OH
1
1
3
4
Cl
Br
phenol
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phenol
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Naming Phenols
17
Step 3
Give the location and name of each substituent
relative to the –OH group.
OH
OH
1
1
3
4
Cl
Br
3-chlorophenol
4-bromophenol
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Learning Check
18
Write the structure of each of the following:
A.
3-pentanol
B. ethyl alcohol
C.
4-methylphenol
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Solution
19
Write the structure of each of the following:
A. 3-pentanol
OH
|
CH3—CH2—CH—CH2—CH3
B. ethyl alcohol
CH3—CH2—OH
OH
C. 4-methylphenol
CH3
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Thiols
20
Thiols
• contain sulfur
• are similar to alcohols
• contain a thiol (–SH) group
• often have strong odors
• are found in cheese, onions, garlic,
and oysters
• are used to detect gas leaks
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Thiols
21
Thiols are named in the IUPAC system by adding thiol to
the alkane name of the longest carbon chain.
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Ethers
22
An ether
• contains an –O– between two carbon groups
• has a common name that gives the alkyl names of the
attached groups, followed by ether
CH3OCH3
CH3CH2OCH3
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Learning Check
23
Write the structure of the following:
A. 3-pentanol
B. ethanethiol
C. diethyl ether
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Solution
24
A. 3-pentanol
OH
|
CH3CH2CHCH2CH3
B. ethanethiol
CH3CH2SH
C. diethyl ether
CH3CH2OCH2CH3
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Ethers as Anesthetics
25
Anesthetics
• inhibit pain signals to the brain
• like diethyl ether, CH3CH2OCH2CH3, were used for over
a century, but caused nausea and were flammable
• developed by the 1960s were nonflammable
Cl F
F
Cl F
H
HCCOCH
F F
F
Ethrane (enflurane)
HCCOCH
H F
H
Penthrane
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Chapter 12 Organic Compounds with
Oxygen and Sulfur
26
12.2
Properties of Alcohols and Ethers
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Classification of Alcohols
27
Classification of alcohols is
• determined by the number of alkyl groups attached to the
carbon bonded to the hydroxyl
• primary (1), secondary (2), or tertiary (3)
Primary (1)
1 group
H
|
CH3—C—OH
|
H
Secondary (2)
2 groups
CH3
|
CH3—C—OH
|
H
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Tertiary (3)
3 groups
CH3
|
CH3—C—OH
|
CH3
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Learning Check
28
Classify each alcohol as primary, secondary, or tertiary.
OH
|
A. CH3—CH—CH2—CH3
B. CH3—CH2—CH2—OH
OH
|
C. CH3—CH2—C—CH2—CH3
|
CH3
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Solution
29
OH
|
A. CH3—CH—CH2—CH3
secondary
B. CH3—CH2—CH2—OH
primary
OH
|
C. CH3—CH2—C—CH2—CH3
|
CH3
tertiary
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Solubility of Alcohols in Water
30
Alcohols
• contain polar OH groups and
form hydrogen bonds with other
alcohol molecules
• that have one to three carbons are
soluble in water
• solubility in water decreases with
increasing number of carbons
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Solubility of Ethers in Water
31
Ethers
• do not have a polar OH group,
but have a COC group
• do not form hydrogen bonds
• with less than four carbons are
slightly soluble in water
• with more than four carbons are
not soluble in water
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Solubility of Alcohols and Ethers in
Water
32
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Solubility of Phenols
33
Phenols
• are slightly soluble in water
• have an OH group that can form hydrogen bonds with water
• can react with water to produce phenoxide ions
• were once used as antiseptics
OH
O-
+ H2O
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+ H3O+
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Learning Check
34
Indicate whether each of the following is soluble in water
and explain why.
A. CH3CH2CH2CH2CH2CH2OH
B. CH3OCH2CH3
C. CH3CH2OH
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Solution
35
Indicate whether each of the following is soluble in water
and explain why.
A. CH3CH2CH2CH2CH2CH2OH
Not soluble
Alcohols with long carbon chains (nonpolar) are not soluble.
B. CH3OCH2CH3
Slightly soluble
Ethers with less than four carbons are only slightly
soluble in water.
C. CH3CH2OH
Soluble
Short-chain alcohols form hydrogen bonds with water.
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Chapter 12 Organic Compounds with
Oxygen and Sulfur
36
12.3
Reactions of Alcohols and Thiols
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Dehydration of Alcohols
37
Alcohols undergo
• dehydration when heated with an acid catalyst
• the loss of –H and –OH from adjacent carbon atoms,
producing an alkene
H OH
| |
H—C—C—H
| |
H H
alcohol
H+, heat
H—C=C—H + H2O
| |
H H
alkene
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Oxidation of 1 Alcohols
38
Alcohols undergo oxidation, increasing the number of
carbon and oxygen bonds.
Primary alcohols are oxidized to produce an aldehyde.
1 bond to O
H OH
|
|
H—C—C—H
| |
H H
1 alcohol
2 bonds to O
oxidation
H O
| ||
H—C—C—H
|
H
aldehyde
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Oxidation of 1 Alcohols
39
Alcohols undergo oxidation, increasing the number of
carbon and oxygen bonds.
Aldehydes can further oxidize to produce a carboxylic acid.
1 bond to O
H O
|
||
H—C—C—H
|
H
aldehyde
2 bonds to O
oxidation
H O
| ||
H—C—C—OH
|
H
carboxylic acid
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Oxidation of 2 Alcohols
40
Secondary alcohols are oxidized to produce a ketone.
To indicate the process of oxidation, [O] is placed over the
reaction arrow.
1 bond to O
2 bonds to O
H OH H
|
| |
H—C—C—C—H
|
| |
H H H
H O H
| || |
H—C—C—C—H
|
|
H
H
[O]
2 alcohol
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ketone
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Oxidation of Tertiary 3 Alcohols
41
Tertiary (3) alcohols do not readily oxidize.
OH
CH3CCH3
CH3
3 alcohol
[O]
no product
no H to oxidize
no reaction
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Oxidation and Reduction
42
In an oxidation,
• there is an increase in the number of C–O bonds
• there is a loss of H
In a reduction,
• there is a decrease in the number of C–O bonds
• there is a gain of H
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Oxidation and Reduction
43
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Methanol Poisoning
44
Methanol
• is also known as methyl alcohol
• is highly toxic and found in windshield washer fluid, Sterno,
and paint strippers
• is rapidly absorbed and oxidized to formaldehyde and then
formic acid
O
[O]
CH3OH
O
[O]
HCH
methyl alcohol formaldehyde
HCOH
formic acid
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Ethanol, CH3CH2OH
45
Ethanol
• acts as a depressant and kills or
disables more people than any
other drug
• is metabolized at a rate of
12–15 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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Effect of Alcohol on the Body
46
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Oxidation of Thiols
47
When thiols undergo oxidation,
• an H atom is lost from each of two –SH groups
• the product is a disulfide
• protein in hair is cross-linked by disulfide bonds found in the
amino acid cysteine
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Learning Check
48
Select the product for the oxidation of
OH
CH3CHCH2CH3
[O]
O
A. CH3CH=CHCH3
B. CH3CCH2CH3
OH
C. CO2 + H2O
D. CH3CHCH2CH3
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Solution
49
Select the product for the oxidation of
OH
[O]
CH3CHCH2CH3
O
The answer is B.
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CH3CCH2CH3
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Learning Check
50
Select the product when CH3–CH2–CH2–OH undergoes each of
the following reactions:
[O]
[O]
CH3—CH2 —CH2OH
B.
C.
1) CH3—CH=CH2
2) CO2 + H2O
O
||
3) CH3—CH2—C—H
O
||
4) CH3—CH2—C—OH
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Solution
51
Select the product when CH3–CH2–CH2–OH undergoes each of
the following reactions:
O
[O]
B. 3)
||
CH3—CH2—CH2OH
CH3—CH2—C—H
[O]
O
C. 4)
||
CH3—CH2—C—OH
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Learning Check
52
Give the primary product for the reaction of
2-propanol when it undergoes
A. oxidation
B. dehydration
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Solution
53
OH
CH3CHCH3 = 2-propanol = C3H8O
A. oxidation
OH
O
2CH3CHCH3 + 9O2
[O]
CH3CCH3 + 6CO2 + 8H2O
B. dehydration
OH
CH3CHCH3
H+, heat
CH3CH=CH2 + H2O
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Chapter 12 Organic Compounds with
Oxygen and Sulfur
54
12.4
Aldehydes and Ketones
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Carbonyl Group in Aldehydes
and Ketones
55
A carbonyl group
• consists of a carbon-oxygen polar
double bond
• has a very electronegative oxygen
atom
• has two lone pair electrons on the
O atom
• has partial positive charge on C
and partial negative charge on O
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O
C
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Carbonyl Group in Aldehydes
and Ketones
56
A carbonyl group
• in an aldehyde is attached
to at least one H atom
• in a ketone is attached to
two carbon groups
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Naming Aldehydes
57
An aldehyde
• has an IUPAC name in which the -e in the alkane name is
changed to -al
• has a common name for the first four aldehydes that use the
following prefixes:
1 carbon, form
2 carbons, acet
3 carbons, propion
4 carbons butyr
followed by aldehyde
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Naming Aldehydes
58
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Naming Aldehydes
59
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Naming Aldehydes
60
Give the IUPAC name for the following aldehydes:
O
||
CH3CH2CH2CHCH
|
CH3
O
C
H
Cl
Cl
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Naming Aldehydes
61
Step 1 Name the longest carbon chain containing the
carbonyl group by replacing the e in the
alkane name with al.
O
O
||
CH3CH2CH2CHCH
|
CH3
pentanal
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C
H
Cl
Cl
benzaldehyde
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Naming Aldehydes
62
Step 2 Name and number substituents by counting the
carbonyl group as carbon 1.
O
O
||
CH3CH2CH2CHCH
|
CH3
C
H
Cl
2-methylpentanal
Cl
3,4-dichlorobenzaldehyde
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Aldehydes in Flavorings
63
Several naturally occurring aldehydes are used as
flavorings for foods and fragrances.
O
O
C
C
H
H
vanillin
HO
OCH3
benzaldehyde
(almonds)
O
C
HC
C
H
H
cinnamaldehyde
cinnamon
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Naming Ketones
64
When naming the following ketones
• in the IUPAC system, the -e in the alkane name is replaced
with -one
• with a common name, the alkyl groups attached to the
carbonyl group are named alphabetically, followed by ketone
O
CH3 CCH3
propanone
(dimethyl ketone)
O
CH3CCH2CH3
2-butanone
(ethyl methyl ketone)
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Naming Ketones
65
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Naming Ketones
66
Name the following ketones using the IUPAC system.
O
||
CH3CH2CHCH2CCH3
|
CH3
O
CH3
CH3
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Naming Ketones
67
Step 1 Name the longest carbon chain that contains the
carbonyl group by replacing the e in the alkane name
with one.
O
O
||
CH3CH2CHCH2CCH3
|
CH3
hexanone
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CH3
CH3
pentanone
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Naming Ketones
68
Step 2 Number the carbon chain starting from the end nearer
the carbonyl group and indicate its location.
O
||
CH3CH2CHCH2CCH3
|
CH3
2-hexanone
O
CH3
CH3
pentanone
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Naming Ketones
69
Step 3 Name and number any substituents on the carbon chain.
O
||
CH3CH2CHCH2CCH3
|
CH3
O
CH3
4-methyl-2-hexanone
CH3
2,3-dimethylcylcopentanone
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Ketones in Common Use
70
Acetone (propanone) is a solvent
used in nail polish remover.
Butanedione is the butter
flavoring used in margarine.
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Learning Check
71
Classify each as an aldehyde or ketone.
O
||
A. CH3—CH2—C—CH3
O
||
B. CH3—C—H
O
CH3
O
|
||
C. CH3—C—CH2—C—H
|
CH3
D.
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Solution
72
Classify each as an aldehyde or ketone.
O
||
A. CH3—CH2—C—CH3
O
||
B. CH3—C—H
aldehyde
ketone
CH3
O
|
||
C. CH3—C—CH2—C—H
|
CH3
aldehyde
O
D.
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ketone
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Learning Check
73
Classify each as an aldehyde, ketone, alcohol, or ether.
O
A. CH3CH2CCH3
CH3
B. CH3OCH3
O
C. CH3CCH2CH
OH
D. CH3CHCH3
CH3
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Solution
74
Classify each as an aldehyde, ketone, alcohol, or ether.
O
A. CH3CH2CCH3
B. CH3OCH3
ketone
CH3
O
C. CH3CCH2CH
CH3
ether
OH
D. CH3CHCH3
aldehyde
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alcohol
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Learning Check
75
Give the IUPAC name for each of the following ketones.
O
A. CH3CH2CH2CH2CCH3
O
B. ClCH2CH2CCH3
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Solution
76
Give the IUPAC name for each of the following ketones.
Step 1 Name the longest carbon chain that contains the
carbonyl group by replacing the e in the alkane name
with one.
O
A. CH3CH2CH2CH2CCH3
pentanone
O
B. ClCH2CH2CCH3
butanone
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Solution
77
Give the IUPAC name for each of the following ketones.
Step 2 Name the carbon chain starting from the end nearer the
carbonyl group and indicate its location.
O
A. CH3CH2CH2CH2CCH3
2-pentanone
O
B. ClCH2CH2CCH3
2-butanone
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Solution
78
Give the IUPAC name for each of the following ketones.
Step 3 Name and number any substituents on the
carbon chain.
O
A. CH3CH2CH2CH2CCH3
2-pentanone
O
B. ClCH2CH2CCH3
4-chloro-2-butanone
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Learning Check
79
Give the IUPAC name for the following aldehyde compounds.
O
||
A. CH3—CH2—CH2—C—H
CH3
O
|
||
B. CH3—C—CH2—C—H
|
CH3
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Solution
80
Give the IUPAC name for the following aldehyde compounds.
Step 1 Name the longest carbon chain containing the carbonyl
group by replacing the e in the alkane name with al.
O
||
A. CH3—CH2—CH2—C—H
CH3
O
|
||
B. CH3—C—CH2—C—H
|
CH3
butanal
butanal
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Solution
81
Give the IUPAC name for the following aldehyde compounds.
Step 2 Name and number substituents by counting the carbonyl
group as carbon 1.
O
||
A. CH3—CH2—CH2—C—H
CH3
O
|
||
B. CH3—C—CH2—C—H
|
CH3
butanal
3,3-dimethylbutanal
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Learning Check
82
Draw the structural formulas for each:
A. 4-methylpentanal
B. 2,3-dichloropropanal
C. 3-methyl-2-butanone
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Solution
83
Draw the structural formulas for each:
CH3
A. 4-methylpentanal
CH3CHCH2CH2CH
Cl
B. 2,3-dichloropropanal
O
O
ClCH2CHCH
CH3 O
C. 3-methyl-2-butanone
CH3CHCCH3
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Chapter 12 Organic Compounds with
Oxygen and Sulfur
84
12.5
Properties of Aldehydes and Ketones
In Tollens’ test, a silver mirror forms when the oxidation of an aldehyde reduces silver
ion to metallic silver. The silvery surface of a mirror is formed in a similar way.
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Physical Properties
85
The polar carbonyl group provides dipole-dipole interactions.
+ -
+ -
C=O
C=O
Because the electronegative oxygen atom forms hydrogen
bonds with water molecules, aldehydes and ketones with one
to four carbons are very soluble.
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Solubility of Aldehydes and Ketones in
Water
86
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition
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Solubility in Water
87
The electronegative O atom of the carbonyl group of aldehydes
and ketones forms hydrogen bonds with water.
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Learning Check
88
Indicate whether each is soluble or insoluble in water.
A. CH3—CH2—CH3
B. CH3—CH2—OH
O
||
C. CH3—CH2—CH2—C—H
O
||
D. CH3—C—CH3
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Solution
89
Indicate whether each is soluble or insoluble in water.
A. CH3—CH2—CH3
insoluble
B. CH3—CH2—OH
soluble
O
||
C. CH3—CH2—CH2—C—H
soluble
O
||
D. CH3—C—CH3
soluble
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Oxidation of Aldehydes
90
Primary alcohols can be oxidized to aldehydes, which can
be easily oxidized to carboxylic acids.
Secondary alcohols can be oxidized to ketones, which
cannot be further oxidized.
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Tollens’ Test
91
In Tollens’ test,
• Tollens’ reagent, which contains Ag+, oxidizes aldehydes but
not ketones.
• Ag+ is reduced to metallic Ag, which appears as a “mirror”
in the test tube.
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Tollens’ Test
92
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Benedict’s Test
93
In Benedict’s test, Benedict’s reagent, which contains Cu2+,
reacts with aldehydes that have an adjacent OH group.
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Benedict’s Test
94
In Benedict’s test,
• an aldehyde is oxidized to a
carboxylic acid, while Cu2+
is reduced to give red
Cu2O(s).
The blue Cu2+ in Benedict’s solution forms a brick-red
solid of Cu2O in a positive test for many sugars and
aldehydes with adjacent hydroxyl groups.
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Reduction of Aldehydes and Ketones
95
Aldehydes and ketones can be reduced by sodium borohydride,
NaBH4, or H2.
The reduction of aldehydes and ketones decreases the number of
carbon–oxygen bonds by addition of hydrogen or loss of oxygen.
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition
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Learning Check
96
Write the structure and name of the organic product
when each is mixed with Tollens’ reagent.
A. butanal
B. acetaldehyde
C. ethyl methyl ketone
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Solution
97
A.
O
O
||
Tollens’
||
CH3—CH2—CH2—C—OH
CH3—CH2—CH2—C—OH
butanal
B.
O
||
Tollens’
CH3—C—H
acetaldehyde
butanoic acid
O
||
CH3—C—OH
acetic acid
C. Ethyl methyl ketone + Tollens’
No reaction
Ketones are not oxidized by Tollens’ reagent.
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Chapter 12 Organic Compounds with
Oxygen and Sulfur
98
12.6
Chiral Molecules
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Isomers
99
Molecules are structural isomers when they have the same
molecular formula, but different bonding arrangements.
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Stereoisomers
100
Stereoisomers have identical molecular formulas, but they
are not structural isomers.
In stereoisomers, the atoms are bonded in the same
sequence but differ in the way they are arranged in space.
When stereoisomers have mirror images that are different,
they are said to have “handedness.”
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Chiral Molecules Have Handedness
101
Chiral molecules
• have the same number of atoms
arranged differently in space
• have one or more chiral carbon
atoms, each of which is bonded to
four different groups
• are like your hands
Try to superimpose your thumbs,
palms, back of hands, and little fingers.
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Some Everyday Chiral and
Achiral Objects
102
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Chiral Carbon Atoms Are Mirror Images
103
• The mirror images of chiral compounds cannot be
superimposed.
• When the H and I atoms are aligned, the Cl and Br atoms
are on opposite sides.
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Achiral Structures Are Superimposable
104
When the mirror image of an achiral structure is rotated, the
structure can be aligned with the initial structure. Thus this
mirror image is superimposable.
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Learning Check
105
Identify each as a chiral or an achiral compound.
Cl
Cl
H
C
CH3
CH2CH3
A.
H
C
Cl
CH3
H
C
H
Br
B.
C.
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CH3
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Solution
106
Identify each as a chiral or an achiral compound.
Cl
Cl
H
C
CH3
H
C
Cl
CH3
H
C
CH3
H
Br
A.
B.
C.
chiral
achiral
chiral
CH2CH3
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Fischer Projections
107
A Fischer projection
• is a two-dimensional representation of a three-dimensional
molecule
• places the most oxidized group at the top
• uses vertical lines in place of dashes for bonds that go back
• uses horizontal lines in place of wedges for bonds that
come forward
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Drawing Fischer Projections
108
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D and L Notations
109
• By convention, the letter L is assigned to the structure with the
–OH on the left.
• The letter D is assigned to the structure with the –OH on
the right.
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Learning Check
110
Indicate whether each pair is a mirror image that cannot be
superimposed (enantiomers).
CH2OH
A.
B.
H
H
C
CH3
CH2OH
and
CH3 C
Br
Br
Cl
Cl
C
CH3
and
CH3 C
H
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition
H
H
H
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Solution
111
Indicate whether each pair is a mirror image that cannot be
superimposed (enantiomers).
CH2OH
A.
B.
H
H
C
CH3
CH2OH
and
CH3 C
Br
Br
Cl
Cl
C
CH3
and
CH3 C
H
Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition
H
Yes
No
H
H
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Concept Map – Organic Molecules
with O and S
112
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