The document summarizes key information about alcohols, phenols, thiols, and ethers from Chapter 12. It discusses the structures, properties, and reactions of these functional groups. Alcohols contain a hydroxyl group (-OH) and are polar due to hydrogen bonding. Their solubility decreases with increasing carbon chain length. Alcohols can be prepared by hydration of alkenes or hydrogenation of carbonyl groups. They undergo oxidation, dehydration, and substitution reactions. Phenols contain a hydroxyl group attached to an aromatic ring. Ethers have an oxygen atom bonded to two alkyl groups instead of a hydroxyl group and alkyl group. Thiols are analogous to alco

1. Chapter 12
Alcohols, Phenols, Thiols, and Ethers
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2. 1. Alcohols: structure and properties
The functional group found on all alcohols is the hydroxyl
group, -OH.
Alcohols are like water molecules, but with an alkyl group
(-R) substituted for one of the hydrogens.
H-OH R-OH
2

3. 1. Alcohols: structure and properties
Since oxygen is more
electronegative than carbon
and hydrogen, the hydroxyl
group makes alcohol molecules
polar.
This polarity, along with the
hydrogen bonded to oxygen,
allows alcohols to hydrogen-
bond.
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4. 1. Alcohols: structure and properties
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5. 1. Alcohols: structure and properties
The strength of hydrogen-bonding causes alcohols to
have higher melting and boiling points than the
corresponding hydrocarbons.
Compound Molar Mass Boiling Point
CH3CH2CH3 44 g/mol -42 oC
CH3CH2OH 46 g/mol +78.5 oC
CH3CH2CH2CH3 58 g/mol -0.5 oC
CH3CH2CH2OH 60 g/mol 97.2 oC
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6. 1. Alcohols: structure and properties
Small alcohol molecules (1-4 carbons) are very soluble in
water.
Alcohols with 5-6 carbons are moderately soluble in
water.
Larger alcohols are not appreciably soluble in water.
WHY?
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7. 1. Alcohols: structure and properties
Name Formula Water solubility*
methanol CH3OH miscible
ethanol C2H5OH miscible
propanol C3H7OH miscible
butanol C4H9OH 0.11
pentanol C5H11OH 0.030
hexanol C6H13OH 0.0058
heptanol C7H15OH 0.0008
*mol/100g at 25oC
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8. 1. Alcohols: structure and properties
The hydroxyl end of an alcohol molecule is hydrophilic.
“Water-loving”
The nonpolar hydrocarbon portion of the alcohol
molecule is hydrophobic.
“Water-fearing”
As the nonpolar portion becomes larger relative to the
polar portion, water solubility decreases.
8

9. 1. Alcohols: structure and properties
The presence of multiple hydroxyl groups on a carbon
chain will increase solubility.
Name Formula Water solubility*
butanol 0.11
1,4-butanediol miscible
Tegrity lecture video
9

10. 1. Alcohols: structure and properties
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11. 1. Alcohols: structure and properties
Here’s Journal question number one!
tag = alcohols
What characteristic of alcohols is responsible for both
their high boiling points and their high degree of
solubility in water? How does this characteristic cause
high boiling points and high solubilities?
11

12. 2. Alcohols: Nomenclature
1) Name the parent compound based on the longest
carbon chain or the carbon ring.
2) Replace the parent name ending –e with –ol.
3) Number the parent chain to give the hydroxyl carbon
the lowest possible number.
4) Identify, name, and number all additional substituents.
12

13. 2. Alcohols: Nomenclature
1) Name the parent compound based on
the longest carbon chain or the carbon
ring.
butane
2) Replace the parent name ending –e with
–ol.
butanol
3) Number the parent chain to give the
hydroxyl carbon the lowest possible
number.
2-butanol
4) Identify, name, and number all
additional substituents.
3-methyl-2-butanol
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14. 2. Alcohols: Nomenclature
Name the following compounds:
pencast
14

15. 2. Alcohols: Nomenclature
Draw structures for the following compounds:
2-methyl-1-propanol
2-chlorocyclopentanol pencast
2,4-dimethylcyclohexanol
2,3-dichloro-3-hexanol
1,2,3-pentanetriol
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16. 4. Classification of alcohols
In an alcohol, the carbon atom with the hydroxyl group (-
OH) attached to it is called the .
What distinguishes the four carbinol carbons above?
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17. 4. Classification of alcohols
Methanol is in a class by itself, with 0 carbons/3
hydrogens attached to the carbinol carbon.
Primary (1o) alcohols have 1 carbon/2 hydrogens
attached to the carbinol carbon.
ethanol
Secondary (2o) alcohols have 2 carbons/1 hydrogen
attached to the carbinol carbon.
2-propanol
Tertiary (3o) alcohols have 3 carbons/0 hydrogens
attached to the carbinol carbon.
2-methyl-2-propanol
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18. 4. Classification of alcohols
Methanol
(1o)
(2o)
(3o)
18

19. 4. Classification of alcohols
Alcohols often react differently depending on their
classification as 1o, 2o, or 3o.
A fourth classification is aromatic alcohol, with the
hydroxyl group attached to a carbon on an aromatic ring.
The simplest of these is phenol.
Tegrity lecture video 19

20. 4. Classification of alcohols
Name each alcohol and classify it as 1o, 2o, or 3o.
pencast
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21. 5. Reactions involving alcohols
Preparation of alcohols: hydration of an alkene
See slides 39-42 of the Chapter 11 powerpoint.
Remember that Markovnikov’s rule applies.
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22. 5. Reactions involving alcohols
Preparation of alcohols: hydrogenation of aldehydes
and ketones.
Addition of H2 to a double bond (C=O)
These reactions are also called reductions (fewer C-O bonds,
more C-H bonds)
catalyst
catalyst
22

23. 5. Reactions involving alcohols
Write a balanced equation for the hydrogenation of
ethanal (two-carbon aldehyde).
Name the product. pencast
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24. 5. Reactions involving alcohols
Write a balanced equation for the hydrogenation of 2-
hexanone (six-carbon ketone).
pencast
Name the product.
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25. 5. Reactions involving alcohols
Dehydration of alcohols
Dehydration is the reverse of hydration.
Dehydration is a type of elimination reaction.
In the presence of heat and a strong acid, -OH and –H are
removed from adjacent carbon atoms.
A double bond is formed between these atoms.
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26. 5. Reactions involving alcohols
Sometimes, more than one product of dehydration is
possible.
major product minor product
2-butanol 2-butene 1-butene
Zaitsev’s rule: In an elimination reaction, the more
highly substituted product alkene will be the major
product.
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27. 5. Reactions involving alcohols
Give the product(s) of dehydration of the following
alcohol. Name the reactant and the product(s).
pencast
27

28. 5. Reactions involving alcohols
Give the product(s) of dehydration of the following
alcohol. Name the reactant and the product(s).
pencast
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29. 5. Reactions involving alcohols
Give the product(s) of
dehydration of this
alcohol. Name the
reactant and the
product(s). pencast
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30. 5. Reactions involving alcohols
Oxidation reactions in organic chemistry
Oxidation is a gain of a bond to oxygen and loss of a bond to
hydrogen.
Reduction is the flip side of oxidation—loss of a bond to oxygen
and gain of a bond to hydrogen.
An oxidizing agent causes oxidation to take place and is
itself reduced.
basic potassium permanganate (KMnO4/OH-)
chromic acid (H2CrO4)
general symbol [O] over the reaction arrow
30

31. 5. Reactions involving alcohols
Oxidation reactions in organic chemistry
Tegrity lecture video 31

32. 5. Reactions involving alcohols
Here’s Journal question #2.
Tag = oxidation
Combustion of an alkane to produce carbon dioxide (and
water) is an oxidation reaction. Now that you know
oxidation involves forming more bonds to oxygen and
fewer bonds to hydrogen, give the [hypothetical] steps in
the combustion (that is, oxidation) of methane to carbon
dioxide. Each step should produce a molecule with one
more carbon-oxygen bond and one less carbon-hydrogen
bond. Name the molecule produced in each step, ending
with carbon dioxide. There are four steps and four
product molecules if you include carbon dioxide.
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33. 5. Reactions involving alcohols
WHY?
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34. 5. Reactions involving alcohols
Tegrity lecture video 34

35. 5. Reactions involving alcohols
Draw the product of oxidation of the following alcohols
and name the product.
propanol
pencast
cyclohexanol
2-methyl-2-hexanol
1-methyl-1-cyclopentanol
3-phenyl-1-propanol
pencast
How can acetone be prepared from propene?
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36. 5. Reactions involving alcohols
When ethanol is metabolized in the liver in the following
series of reactions, catalyzed by liver enzymes.
What causes a hangover?
Step 2 of oxidation
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37. 6. Oxidation and reduction in living systems
In inorganic reactions, oxidation and reduction are often
accompanied by changes in charge and transfer of
electrons.
Oxidation of sodium: Na  Na+ + e-
Reduction of chlorine: Cl + e-  Cl-
In organic systems, there are normally no changes in
charge or obvious transfers of electrons.
Oxidation: more bonds to oxygen or fewer bonds to hydrogen
Reduction: fewer bonds to oxygen or more bonds to hydrogen
37

38. 6. Oxidation and reduction in living systems
more oxidized form
alkane alcohol aldehyde carboxylic acid
more reduced form
38

39. 7. Phenols
Compounds with a hydroxyl group attached to a benzene
ring are called phenols.
As with alcohols, the hydroxyl group makes the
compound polar and can participate in hydrogen
bonding.
Smaller phenols are slightly soluble in water.
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40. 7. Phenols
The compound phenol
is a solid at room temperatures;
is colorless and poisonous;
has a penetrating odor;
turns red when exposed to air.
The acid-base indicator
phenolphthalein
has two phenolic hydroxyl groups;
is colorless in acidic solution;
is deep magenta in basic solution.
40

41. 8. Ethers
Ethers are similar to alcohols, but the –H of the hydroxyl
group is replaced by another –R group.
alcohol ether
Intermolecular forces are weaker in ethers than in
alcohols because the absence of an O-H bond precludes
hydrogen bonding.
Ethers are slightly polar due to the C-O bonds.
41

42. 8. Ethers
Boiling points of ethers are
higher than for the corresponding alkanes.
much lower than for the corresponding alcohols.
Tegrity lecture video 42

43. 8. Naming ethers
The IUPAC names for ethers are based on the alkane
name of the longest chain attached to the oxygen.
The shorter chain is named as an alkoxy substituent, an
alkane with the -ane replaced by –oxy.
CH3CH2CH2CH2CH2-O-CH3
1-methoxypentane
Give the IUPAC names for the ethers on the next slide.
43

44. 8. Naming ethers
Give the IUPAC names for the following ethers.
pencast
44

45. 8. Synthesis of ethers
A dehydration (removal of water) reaction between two
alcohols will produce an ether.
Heat and the presence of hydrogen ions are necessary for
the reaction to take place.
ethanol + ethanol  ethoxyethane + water
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46. 8. Synthesis of ethers
If two different alcohols undergo a dehydration, a
mixture of products is possible.
methoxyethane
ethanol + methanol
methoxymethane
ethoxyethane
46

47. 8. Synthesis of ethers
And finally, Journal question #3.
Tag = solubility
Compare the relative solubilities in water of alkanes,
alcohols, phenols, and ethers. Explain their relative
solubilities in terms of their differing molecular structures
and their intermolecular forces with water molecules.
47

48. 9. Thiols
The sulfhydryl group, -SH, is analogous
to the hydroxyl group, -OH.
A compound with a sulfhydryl group is
called a thiol.
Thiols are named by adding the suffix
thiol to the name of the parent
compound.
48

49. 9. Thiols
Name the following compounds:
pencast
49

50. 9. Thiols
Draw structures for the following compounds:
1,3-butanedithiol
2-methyl-2-pentanethiol
pencast
2-chloro-2-propanethiol
cyclopentanethiol
50

51. 9. Thiols
Two thiols can be oxidized (lose hydrogen) to form a
disulfide.
+ 2 H+ + 2 e-
Disulfide bonds are important for the structure and
shape of many proteins. (more about this in Module 8)
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52. 9. Thiols
52

53. 9. Thiols
Synthesis of insulin
Disulfide bonds form to shape preproinsulin.
Loss of the gray portion of the chain forms insulin .
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