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Alkanoic acids and EstersIntermediate 2 ChemistryUnit 2(b)(c)
Examples
Examples
Examples
Functional group
C
O
O H
-COOH
The carboxyl group
Naming• As with other organic molecules,
except ending is –anoic acid.
CH
OH
OC
H
H
CC
H
H
C
C
H
H
H
H
H
CH
H
H
CH3
CH3
CH3
CH2 COOHCH2CH CH
Reactions• React with alkanols to produce esters.
R C
O
O H
+ ROH
1
RCO
O 1
R +O
H H
ESTER
Producing esters
• Because water is produced, this is called a condensation reaction.
Alkanol + Alkanoic acid
Ester + Water
Specific example
C
H
OCH
H H
O
C
H
OC
H
HH
H
H
+ O
H H+C
HO
C
H
H HOH
H
C C H
H
• The –OH is removed from the ACID
• The –H is removed from the ALCOHOL
CH3CH2CH2OH + HOOCCH2CH3 CH3CH2CH2OOCCH2CH3
Using SSF:
• The C with H atoms attached is from the alcohol
• The C without H atoms attached is from the acid
• Use structural formulae to illustrate the reaction of:– Methanol with butanoic acid;– Propanoic acid with ethanol.
Naming esters• 1st part of name comes from the alkanol
– e.g. methanol produces methyl-, ethanol produces ethyl- etc...
• 2nd part of name comes from alkanoic acid– e.g. methanoic acid produces –methanoate,
ethanoic acid produces –ethanoate etc...
Practice• Name the esters produced from...
– Butanol and pentanoic acid– Heptanoic acid and ethanol
• Name the alkanols and alkanoic acids used to produce...– Pentyl butanoate– Methyl octanoate
The reverse reaction• The formation of esters is a reversible
reaction.
• This means that an alkanol and alkanoic acid can be produced from an ester.
Alkanol + Alkanoic acid
Ester + Water
This breakdown using water is called a “hydrolysis” reaction.
C
HO
C
H
H HOH
H
C C H
H
COH
CH
H O H
Ethanoic acid
C
O
H
CH
H
H
H H
Ethanol
CH3COOCH2CH2CH3
CH3COOH
Ethanoic acid
CH3CH2CH2OHPropan –1- ol
C C C
O
O C C C C
H
H
H
H
HH
H H H H
H
HH H