CHAPTER 17: Hydroxy Compounds
17.1 Introduction to Alcohols
17.2 Reactions of Alcohols
Learning outcomes:
(a) recall the chemistry of alcohols, exemplified by ethanol:
(i) combustion.
(ii) substitution to give halogenoalkanes.
(iii) reaction with sodium.
(iv) oxidation to carbonyl compounds and carboxylic acids.
(v) dehydration to alkenes.
(vi) formation of esters by esterification with carboxylic acids.
(b) (i) classify hydroxy compounds into primary, secondary and tertiary alcohols.
(ii) suggest characteristic distinguishing reactions, e.g. mild oxidation.
, 17.1 Introduction to Alcohols
What are alcohols?
1) Alcohols are compounds in which one or more hydrogen atoms in an alkane
have been replaced by an -OH group.
2) Alcohols can be classified as primary, secondary or tertiary depending on
the number of alkyl groups(R groups) attached to the carbon atom holding the
-OH group.
3) Some examples of alcohols:
Physical properties of alcohols
1) i. Alcohols are soluble in water because they can form
hydrogen bonds with water molecules.
ii. However, the solubility decreases as the number of
carbon atoms increases. This is because the presence of
long hydrocarbon tail disrupts the effectiveness of hydrogen bonding.
2) i. Alcohols have higher boiling points than the
alkanes with similar Mr due to the presence of
intermolecular hydrogen bonding in addition
of van der Waals' forces of attraction.
ii. The boiling point increases as the number of
carbon atoms increases. This is because there
are more electrons, hence more temporary
dipoles can be set up. More energy is required
to overcome these forces.
17.1 Introduction to Alcohols
17.2 Reactions of Alcohols
Learning outcomes:
(a) recall the chemistry of alcohols, exemplified by ethanol:
(i) combustion.
(ii) substitution to give halogenoalkanes.
(iii) reaction with sodium.
(iv) oxidation to carbonyl compounds and carboxylic acids.
(v) dehydration to alkenes.
(vi) formation of esters by esterification with carboxylic acids.
(b) (i) classify hydroxy compounds into primary, secondary and tertiary alcohols.
(ii) suggest characteristic distinguishing reactions, e.g. mild oxidation.
, 17.1 Introduction to Alcohols
What are alcohols?
1) Alcohols are compounds in which one or more hydrogen atoms in an alkane
have been replaced by an -OH group.
2) Alcohols can be classified as primary, secondary or tertiary depending on
the number of alkyl groups(R groups) attached to the carbon atom holding the
-OH group.
3) Some examples of alcohols:
Physical properties of alcohols
1) i. Alcohols are soluble in water because they can form
hydrogen bonds with water molecules.
ii. However, the solubility decreases as the number of
carbon atoms increases. This is because the presence of
long hydrocarbon tail disrupts the effectiveness of hydrogen bonding.
2) i. Alcohols have higher boiling points than the
alkanes with similar Mr due to the presence of
intermolecular hydrogen bonding in addition
of van der Waals' forces of attraction.
ii. The boiling point increases as the number of
carbon atoms increases. This is because there
are more electrons, hence more temporary
dipoles can be set up. More energy is required
to overcome these forces.
