1.6 Carboxylic Acids and
Esters
Learning Goals …
… name and draw carboxylic acids
… name and draw esters
Carboxylic Acids
• contain the carboxyl group located at the end of a parent
chain
General formula:
O
R–C
R-COOH
OH
• name carboxylic acids by replacing the – e with – oic acid
• number chain so that the carboxyl group is at position #1
CH3
O
II
C OH
ethanoic acid (acetic acid)
CH3
CH3 – C – CH2 – C = 0
CH3
3,3-dimethylbutanoic acid
OH
4-methylpentanoic acid
benzoic acid
H2C C
O
OH
phenylethanoic acid
Properties of Carboxylic acids
• polar and weakly acidic
• hydrogen bonding can occur between molecules and with
water
• very high boiling points due to strong Hydrogen bonds
• often have unpleasant odours
• the –OH group does NOT behave like the basic hydroxide
ion – only the H+ ion is lost in solution to form an acid
Esters
General formula:
O
II
R–C
OR’
R-COOR’
O
II
R–C
main chain
OR’
alkyl group
To name an ester:
1. Name the alkyl group attached to the O, indicate
position #
2. Name the parent chain which includes the C=O
group, replacing the ending with –oate
3. Put the 2 names together (but as separate words)
O
II
CH3CH2CH2C-O-CH2CH3
O
II
H C-O-CH2CH2CH3
ethyl butanoate
1-propyl methanoate
Note: main chain does not
have to be the longest chain
CH3CH2COOCH2(CH3)CH2CH3
O
II
CH3CH2C-O-CH2CH2CH3
CH3
2-butyl propanoate
2-butyl methylpropanoate
Properties of Esters
• polar
• low boiling points
• ester groups are found in fats and oils
• often produce pleasant odours and tastes, such
as in fruits. As a result, they are often used for
perfumes and artificial flavours
Self Check
How prepared am I to start my homework? Can I …
… name and draw carboxylic acids
… name and draw esters
HOMEWORK
p48 #1, 2
p50 #1, 2
p55 #1,2