This document provides an introduction to alcohols. It begins by defining alcohols and phenols. It then discusses the classification of alcohols as primary, secondary, or tertiary based on the carbon atom bonded to the hydroxyl group. The document outlines some common nomenclature and naming conventions for alcohols and phenols. It also discusses some typical physical properties of alcohols like boiling point, solubility, and acidity due to hydrogen bonding. Finally, it briefly introduces some common preparation methods for alcohols like Grignard synthesis and hydrolysis of alkyl halides.

1. CHAPTER 1:
ALCOHOLS
NORFAZRIN MOHD HANIF
FACULTY OF APPLIED SCIENCE
UITM NEGERI SEMBILAN

2. SUBTOPICS
Nomenclature
– common and IUPAC names for alcohols & phenols
Classification of alcohol as 1°, 2°, and 3°.
Physical properties of alcohol.
Preparation of alcohol
–Grignard synthesis
–Hydrolysis of alkyl halides
–Industrial and laboratory preparations of ethyl alcohol
Reactions of alcohol
–Oxidation
–Esterification
–Dehydration
–Halogenation
–Formation of alkoxides

3. INTRODUCTION
 Alcohols are compounds whose molecules have a hydroxyl group
(-OH) attached to:
 saturated C atom of a simple alkyl group
CH3 OH
Methanol
CH3 CH2 OH
Ethanol
OH
CH3 CH2 CH3
2-Propanol
 unsaturated C atom of an alkenyl or alkynyl group
HC CH CH2 OH
H2C CH CH2 OH
2-Propynol
2-Propenol
 Compounds that have –OH group attached directly to a benzene ring
are called phenol
Phenol
OH

4. CLASSIFICATION
• According to the type of carbinol carbon atom (C bonded to the –OH group).
C
OH
Classes:
i) Primary alcohol
- -OH group attached to a primary carbon atom
- one or no alkyl group attached to the carbon bonded to the –OH group
ii) Secondary alcohol
- -OH group attached to a secondary carbon atom
- two alkyl group attached to the carbon bonded to the –OH group
iii) Tertiary alcohol
- -OH group attached to a tertiary carbon atom
- three alkyl group attached to the carbon bonded to the –OH group

5. CLASSIFICATION
Primary (1°) Alcohol
H
H
H
C
C
H
H
H
H
OH
H
Tertiary (3°) Alcohol
H
H
H
H
C
H
H
C
C
C
H
OH
H
H
H
H
C
C
C
H
H
C
Secondary (2°) Alcohol
OH
H
H

6. CLASSIFICATION
Polyhydroxy Alcohols
• Alcohols that contain more than one OH group attached to
different carbons are called polyhydroxy alcohols.
• Monohydroxy: one OH group per molecule.
• Dihydroxy: two OH groups per molecule.
• Trihydroxy: three OH groups per molecule.

7. NOMENCLATURE
Select
1 continuous the longest
chain of carbon
2
atoms containing –-OH .
a. IUPAC names
b. Common names
3
Change the name of the
alkane corresponding to this
chain by dropping the final-e
and adding the suffix –ol.
Number the parent chain to
give the -OH group the lowest
possible number.
Name the alkyl group followed by
the word alcohol

8. NOMENCLATURE
 Examples
OH
OH
IUPAC :
1-Propanol
COMMON: (Propyl alcohol)
OH
2-Propan ol
(Isoprop yl alcoh ol)
OH
OH
IUPAC :
2-Butanol
COMMON:(s ec-Butyl alcohol)
2-Meth yl-1-p ropan ol
(Isobutyl alcohol)
1-Bu tanol
(Bu tyl alcoh ol)
OH
2-Meth yl-2-p ropan ol
(tert -Butyl alcohol)

9. NOMENCLATURE
 Compounds containing more than one -OH group are named
diols, triols, etc.
CH3 CH CH2
CH2 CH2
HO OH
O H OH
1,2-Ethanediol
(Ethylene glycol)
1,2-Propanediol
(Propylene glycol)
CH2 CH CH2
H O H O OH
1,2,3-Propanetriol
(Glycerol, Glycerine)

10. NOMENCLATURE
 Unsaturated alcohols
 Name compounds containing a double bond and an
alcohol group as alkenol.
 Give the alcohol carbon the lower number.
 Examples:
CH3
OH
H3C C CH CH CH3
H2C CH CH CH3
OH
3-Buten-2-ol
4-Methyl-3-penten-2-ol

11. NOMENCLATURE
 Unsaturated alcohols
 Name compounds containing a triple bond and an alcohol
group as alkynol.
 Give the alcohol carbon the lower number.
 Examples:
OH
HC C CH2CH2 OH
3-Butyn-1-ol
H3C C CH 2 C CH
CH3
2-Methyl-4-Pentyn-2-ol

12. NOMENCLATURE - Phenol
 Phenols is the parent name & the substituent is simply indicated by
prefix.
COMMON:
IUPAC: phenol
3-Bromophenol
2-Methylphenol

13. NOMENCLATURE - Phenol
COMMON:
IUPAC:
1,2-Benzenediol
1,3-Benzenediol
1,4-Benzenediol

14. PHYSICAL PROPERTIES
• PHYSICAL STATES OF ALCOHOLS
- simple aliphatic alcohols and lower aromatic alcohols
(such as phenylmethanol, C6H5CH2OH) → liquids at
room temperature.
- highly branched alcohols and alcohols with twelve or
more carbon atoms → solids.

15. PHYSICAL PROPERTIES
 Alcohols are polar compounds
+
+
O
H
……………......... O
hydrogen
bonding
+C
H
H
H
H
+C
H
H
H
they interact with themselves and with other polar
compounds by dipole-dipole interactions
 Dipole-dipole interaction: the attraction between the
positive end of one dipole and the negative end of
another

16. PHYSICAL PROPERTIES
 Hydrogen bonding: when the positive end of one
dipole is a H bonded to F, O, or N (atoms of high
electronegativity) and the other end is F, O, or N
▫ the strength of hydrogen bonding in water is
approximately 21 kJ (5 kcal)/mol
▫ hydrogen bonds are considerably weaker than
covalent bonds
▫ nonetheless, they can have a significant effect on
physical properties

17. Boiling point & solubility
 In relation to alkanes of comparable size and
molecular weight, alcohols
– have higher boiling points
– are more soluble in water
 The presence of additional -OH groups in a molecule
further increases solubility in water and boiling point

18. A. Solubility
i) Alcohols with short carbon chains (such as methanol, ethanol, and
propanol) dissolve in water.
- when alcohols dissolve in water, hydrogen bonds are formed
between the –OH group of the alcohol molecule and the –OH
group of the water molecule.
ii) The solubility of alcohols in water decreases sharply with the
increasing length of the carbon chain. Higher alcohols are insoluble
in water.
- alcohol contains a polar end (-OH group) called ‘hydrophilic’
and a non-polar end (the alkyl group) called ‘hydrophobic’.
- the water solubility decreases as the alkyl group becomes
larger.

19. A. Solubility
iii) alcohols with more than one hydroxyl group (polyhydroxy
alcohols) are more soluble than monohydroxy alcohols with the
same number of carbon atoms. This is because they can form
more hydrogen bonds with water molecule.
iv) branched hydrocarbon increases the solubility of alcohol in
water.
- reason: branched hydrocarbon cause the hydrophobic region
becomes compact.
* Phenol is unusually soluble (9.3%) because of its compact
shape and the particularly strong hydrogen bonds formed
between phenolic –OH groups and water molecules.

20. A. Solubility
 Use basic solubility rule: “like dissolves like”
 Each
alcohol
consists
of
a
nonpolar
carbon
chain
(hydrophobic part) and a polar OH group (hydrophilic part).
As water is polar, it attracts OH group while carbon chain
on the other hand as nonpolar is repelled. Solubility of
alcohols is determined by the stronger of the two forces.
 Another factor in understanding solubility is the capability
to form hydrogen bonding to water.
+
O
H
H
δ+
………….. H O
+C
H
H
H
hydrogen
bonding

21. A. Solubility
MW
bp
(°C)
Solubility
in Water
Structural Formula
Name
CH3 OH
Methanol
Ethane
32
30
65
-89
Infinite
Insoluble
CH3 CH2 CH3
Ethanol
Propane
46
44
78
-42
Infinite
Insoluble
CH3 CH2 CH2 OH
CH3 CH2 CH2 CH3
1-Propanol
Butane
60
58
97
0
Infinite
Insoluble
CH3 ( CH 2 ) 2 CH 2 OH
1-Butanol
Pentane
74
72
117
36
8 g/100 g
Insoluble
90
88
86
230
138
69
Infinite
2.3 g/100 g
Insoluble
CH3 CH3
CH3 CH2 OH
CH3 ( CH 2 ) 3 CH 3
HOCH2 ( CH2 ) 2 CH2 OH 1,4-Butanediol
CH3 ( CH 2 ) 3 CH 2 OH
1-Pentanol
CH3 ( CH 2 ) 4 CH 3
Hexane

22. B. Boiling point
i) The boiling points of alcohols are higher than those of alkanes and
chloroalkanes of similar relative molecular mass.
- For example:
C2H5OH
CH3CH2CH3
CH3Cl
Relative molecular mass:
46
44
50.5
Boiling point:
78°C
-42°C
-24°C
- Reason:
* intermolecular hydrogen bonds exist between the –OH
groups in the alcohol molecules.
R
δ-
O
H
Ar
δ+
H
hydrogen bonding
O
R
O
δ-
δ-
H
δ+
H
Ar
O
hydrogen bonding
δ-
ii) Branched chain alcohols boils at a lower temperature (more volatile) than the
straight chain alcohols with the same number of carbon atoms.

23. B. Boiling point
CH3CH2 OH
Ethanol
bp 78° C
CH3OCH3
Dimethyl ether
bp -24°C
CH3CH3
Ethane
bp -89°C
• Their boiling points are dramatically different
– ethanol forms intermolecular hydrogen bonds which
increase attractive forces between its molecules
resulting in a higher boiling point
– there is no comparable attractive force between
molecules of dimethyl ether & ethane.

24. OCTOBER 2008
APRIL 2009

25. C. Acidity
• Alcohol is weakly acidic.
• In aqueous solution, alcohol will donated its proton to water
molecule to give an alkoxide ion (R-O-).
R-OH + H2O
R-O- + H3O+
Ka = ~ 10-16 to 10-18
alkoxide ion
Example
CH3CH2-OH + H2O

CH3CH2-O- + H3O+
The acid-dissociation constant, Ka, of an alcohol is defined by the
equilibrium
K
a
Ka = [H3O+] [RO-]
R-OH + H2O
[ROH]
R-O- + H3O+
pKa = - log (Ka)
* More smaller the pKa
value, the alcohol is
more acidic

26. C. Acidity
 Alcohol is weakly acidic.
 In aqueous solution, alcohol will donated its proton to water
molecule to give an alkoxide ion (R-O-).
CH3 O H + :O H
H
Ka =
+
CH3 O: + H O H
alkoxide ion
H
[ CH3 O-] [H3 O+ ]
[ CH3 OH]
–
= 1 0 - 15 .5
pKa = 1 5 .5
pKa decrease, acidity increase

27. C. Acidity
Compoun d
Structural
Formula
pK a
Hyd rogen ch loride
HCl
-7
A cetic acid
CH3 COOH
Meth anol
CH3 OH
15.5
Water
Ethanol
H2 O
15.7
CH3 CH 2 OH
15.9
2-Prop anol
( CH3 ) 2 CHOH
17
2-Methyl-2-prop anol
( CH3 ) 3 COH
18
4.8
Stronger
acid
Weaker
acid
*A lso given for comparison are pK a values for w ater,
acetic acid, an d hydrogen chloride.

28. C. Acidity
H 2O
Water
pKa = 15.7
CH3OH
Methanol
pKa = 15.5
CH3CH2OH
Ethanol
pKa = 15.9
CH3CH2(OH)CH3
2-Propanol
pKa = 17.0
 Acidity depends primarily on the degree of stabilization and
solvation of the alkoxide ion
▫ the negatively charged oxygens of methanol and ethanol are
about as accessible as hydroxide ion for solvation; these
alcohol are about as acidic as water
▫ as the bulk of the alkyl group increases, the ability of water
to solvate the alkoxide decreases, the acidity of the alcohol
decreases, and the basicity of the alkoxide ion increases

29. C. Acidity of phenols
• Phenol is a stronger acid than alcohols and water.
R-OH + H2O
alcohol
OH
R-O- + H3O+
Ka = ~ 10-16 to 10-18
alkoxide ion
H2O
phenol
H 2 O + H2 O
O-
H3O+
Ka = 1.2 x 10-10
phenoxide ion
HO- + H3O+
Ka = 1.8 x 10-16
hydroxide ion
Phenol is more acidic than alcohols by considering the
resonance effect.

30. C. Acidity of phenols
ii) The phenoxide ion
- one of the lone pairs of electrons on the oxygen atom is delocalised
into the benzene ring.
- the phenoxide ion is more stable than the alkoxide ion because the
negative charge is not confined to the oxygen atom but delocalised
into the benzene ring.
- the phenoxide ion is resonance stabilised by the benzene ring and
this decreases the tendency for the phenoxide ion to react with H3O+.
O
O
O
O

31. C. Acidity
i) The alkoxide ion (RO-)
- the negative charge is confined to the oxygen and is not
spread over the alkyl group.
- this makes the RO- ion less stable and more susceptible to
attack by positive ions such as H+ ions.

32. PREPARATION
 Grignard Synthesis
 Hydrolysis of alkyl halides
 Acid-catalyzed Hydration of
alkenes

33. 1.Grignard Synthesis
• The grignard reagent (RMgX) is prepared by the reaction of
metallic magnesium with the appropriate organic halide. This
reaction is always carried out in an ether solvent, which is
needed to solvate and stabilize the Grignard reagent as it forms.
R-X + Mg
(X = Cl, Br or I)


CH3CH2OCH2CH3
R-Mg-X
organomagnesium halide
(Grignard reagent)
Grignard reagents may be made from primary, secondary, and
tertiary alkyl halides, as well as from vinyl and aryl halides.
Alkyl iodides are the most reactive halides, followed by bromides
and chlorides. Alkyl fluorides generally do not react.

34. 1.Grignard Synthesis
EXAMPLES
ether
Mg
CH3I
CH3CH2Br
Br
Mg
Mg
ether
CH3MgI
CH3CH2MgBr
ether
MgBr

35. 1.Grignard Synthesis
General formula:
R
MgX +
Grignard
reagent
C
O
• Grignard reagents
act as nucleophiles
toward the carbonyl
group
CH3
H3C
Ether
H3O+
H3C Carbonyl
compound
R
OH
C
CH3
alcohol
 Grignard Reagents react with Formaldehyde to give a 1° alcohol
H
H
CH 3CH 2 MgBr +
alkyl halide
C
O
Ether
H3O+
CH 3CH 2 C
H
H
alcohol
OH

36. 1.Grignard Synthesis
 Grignard Reagents react with all other aldehyde to give a 2° alcohol
+ C
R MgX
R'
R'
R'
O
Ether
R
C
H
O MgX
H3O+
R
C
OH
H
H
2o alcohol
aldehyde
 Grignard Reagents react with ketone to give a 3° alcohol
R'
R MgX
+ C
R''
Ketone
R'
R'
O
Ether
R
C
O MgX
NH4Cl
R
C
H2O
R''
R''
3o alcohol
OH

37. 2. Hydrolysis of alkyl halide
General formula:
R
X
+ OH-
Δ
Alkyl Halide
OH + HX
R
Alcohol
Examples:
CH3 Cl + OH-
Δ
CH3CH2CH2 Cl + OH-
(CH 3)2CH Br + OH-
CH3 OH + HCl
Δ
Δ
?
?
• Alkyl halides can be
converted to
alcohols using
water or hydroxide
as the nucleophile.
• Mechanism is a
simple nucleophilic
substitution

38. 3. Acid catalyzed hydration of alkene
General formula:
H3C
CH3
C
H3C
C
Alkene
H
+ H2O
H+
C
H3C
OH
C
CH3
H3C
CH3
• Note that this is not
a reaction
mechanism, but an
CH3
equation for the
overall reaction.
Examples:
H
H2 C
CH 2
+ H2O
H+
OH
C
C
H
Ethene
H
• Hydronium ion is a
required catalyst.
H
Ethanol
H
Industrial &
laboratory
preparation of
ethanol

39. 3. Acid catalyzed hydration of alkene
Examples:
CH3
CH3 C
CH3 H
CH3 H
CHCH 3 + H2O
H+
CH3 C
OH
2-Methyl-2-butene
C
CH3
H
2-Methyl-2-butanol
(Major product)
+
CH3 C
H
C
CH3
OH
3-Methyl-2-butanol
(Little formed)
* Markovnikov’s rule : in the addition of H-OH to an alkene, the H atom adds to
the C atom of the double bond that already has the greater number of H atom.

40. REACTION





Oxidation
Dehydration
Halogenation
Esterification
Formation of alkoxides

41. 1. Oxidation

42. 1. Oxidation
 Oxidation of 1°Alcohol to Aldehyde : RCH2-OH
[O]
RCHO
O
CH3CH 2OH + PCC
Ethanol
CH2CI2
o
25 C
CH3 C H
Ethanal
PCC: Pyridinium chlorochromate
 Oxidation of 1°Alcohol to Carboxylic Acid : RCH2-OH
O
CH3CH 2 OH
Ethanol
H2CrO4
acetone
35oC
CH3 C OH
Ethanoic Acid
O
CH3CH 2 OH
Ethanol
KMnO4/ H+
CH3 C OH
Ethanoic Acid
[O]
RCOOH

43. 1. Oxidation
O
OH
 Oxidation of 2°Alcohol to Ketone :
R CHR'
[O]
O
OH
CH3CHCH2 CH3
H2CrO4
acetone
35oC
CH3CCH2CH3
2-Butanone
2-Butanol
O
OH
KMnO4/H+
cyclohexanol
cyclohexanone
R C R'

44. 1. Oxidation
 A Chemical Test for 1o, 2o and 3o Alcohol
1oAlcohol
CH3CH 2 OH
Ethanol
H2CrO4
acetone
35oC
orange
OH
2oAlcohol
CH3CHCH 2CH3
2-Butanol
O
CH3 C OH
3oAlcohol
CH3 C CH3
CH3
2-Methyl-2-propanol
Cr3+
green
Ethanoic Acid
O
H2CrO4
acetone
35oC
CH3C CH 2 CH3 +
2-Butanone
orange
OH
+
H2CrO4
acetone
35oC
No reaction!
Cr3+
green

45. 2. Dehydration
• When heated with strong acids catalysts (most commonly H2SO4,
H3PO4), alcohols typically undergo a reactions to generate an alkene and
water. Also known as dehydration since it involves the removal of a
molecule of water.
• Dehydration of alcohols will formed alkenes and the products will followed
Zaitsev’s rule .
R-CH2-CH2-OH
conc. H2SO4
R-CH=CH2 + H2O
* Zaitsev’s rule : The major product of the reaction favor the more stable alkene.
+
H
CH3CH2-CH-CH3
OH
2-butanol
CH3CH2-CH=CH2 + H2O
+
H
1-butene
CH3CH=CH-CH3 + H2O
2-butene
major product

46. 2. Dehydration
 Dehydration of Alcohol to form Alkene:
H3C
H3C
C
H3C
CH3
C
H+
CH3
OH
H3C
CH3
C
C
180oC
H3C
+ H2O
CH3
 Dehydration of Alcohol to form Ether:
H3C
H3C
C
H3C
CH3
C
OH
H+
CH3
140oC
H3C
H3C
C
H3C
CH3
CH3 CH3
C O
C
OH
CH3CH3
C
CH3+ H2O

47. 2. Dehydration
Examples:
CH3 CH2OH
H+
H2C
CH2
o
180 C
Ethene
H+
CH3 CH2OCH2CH3
o
140 C
Diethyl ether

48. 3. Halogenation

Halogenation of Alcohol to form Alkyl halide from
1.
Hydrogen Halide (H-X)
2.
Phosphorus trihalide (PX3)
3.
Thionyl Chloride (SOCl2)
1. Hydrogen Halide (H-X)
R
OH +
H
X
R
hydrogen
halide
X
+ H2O
alkyl halide
Examples:
CH3CH2 OH +
H
Br
CH3CH2 Br + H2O
X = Cl, Br, I

49. 3. Halogenation
LUCAS’S TEST:
(CH 3)3COH +
3o
2
1
25oC
H
Cl
ZnCl2
o
25 C
H
Cl
(CH 3)3C
Cl + H2O
Immediate white
cloudiness of solution
formed
(CH 3)2CH Cl + H2O
White cloudiness of
solution formed after 5
min
Clear homogenous solution
CH3CH2CH2CH2 OH +
o
Cl
Clear homogenous solution
(CH 3)2CHOH +
o
H
ZnCl2
ZnCl2
o
25 C
No reaction
Clear homogenous solution
•LUCAS TEST : used to differentiate 3o, 2o and 1o alcohol.
• Alcohol’s reactivity : 3o>2o>1o

50. 3. Halogenation
2. Phosphorus trihalide (PX3)
3R
OH + P X3
3R
X + H3PO3
X = Cl, Br, I
CH3 OH + P Br3
CH3 Br
3. Thionyl Chloride (SOCl2)
R
OH + SOCl 2
CH3 OH + SOCl 2
R
Cl + SO2 + HCl
CH3 Cl + SO2 + HCl

51. 4. Esterification
The reaction between an alcohol and a carboxylic acid to form
an ester and H2O.
O
R
C
O
H+
O
H
H O
carboxylic acid
ethanol
O
CH3
C
methanol
H+ = catalyst
O
R'
H2O
O
H+
O
H
ethanoic acid
C OH
benzoic acid
C
ester
O
CH3-O-H
R
alcohol
EXAMPLES
CH3CH2-O-H
R'
CH3
C
OCH2CH3
ethyl ethanoate
H+
O
C OCH3
methyl benzoate
H2O
H2O

52. 4. Esterification
Esterification also occurs when alcohols react with
derivatives of carboxylic acids such as acid chlorides
General formula:
O
R' OH +
O
R C Cl
R C OR'
Acid Chloride
Ester
+ HCl
Examples:
O
CH3 OH
+
C6H5 C Cl
O
C6H5C OCH3 + HCl

53. 5. Formation of alkoxides
General formula:
2R
OH + 2Na
- +
2RO Na
+ H2
alkoxide salt
2R
OH + 2K
- +
2RO K
alkoxide salt
R
OH + NaOH
+ H2
no reaction
1o>2o>3o alcohol
* Reactivity towards active metal:

54. End of Chapter 1…
Thank you