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