Naming Structural Formulae
Chemistry: Cambridge International GCSE Supplement, topic 11.2.4
Naming Structural Formulae
Esters are named by combining the alcohol part with the carboxylic acid part.
How are esters named?
- The name of an ester comes from two parts:
- The alcohol part gives the –yl ending.
- Ethanol → ethyl
- Methanol → methyl
- Butanol → butyl
- The carboxylic acid part gives the –oate ending.
- Ethanoic acid → ethanoate
- Methanoic acid → methanoate
- Butanoic acid → butanoate
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Putting together ester names
- To complete naming an ester, put both the alcohol and acid parts together.
- Example 1: Ethyl ethanoate
- Ethanol → ethyl
- Ethanoic acid → ethanoate
- Example 2: Propyl butanoate
- Propanol → propyl
- Butanoic acid → butanoate
Drawing and naming
- A displayed formula shows all atoms and bonds.
- In esters:
- The C=O group (carbonyl) is bonded to an –O–R group.
- Example:
- The picture shows the structure CH3COOCH2CH3.
- This is ethyl ethanoate.
Drawing and naming 2
- To name an ester from its formula:
- Identify the acid part (the C=O group)
- Count the carbons in this part to get the '-oate' name.
- Identify the alcohol part (the single-bonded oxygen atom).
- Count the carbons in this part to get the '-yl' name.
- To draw an ester from its name:
- Draw the acid part based on the '-oate' name.
- Draw the alcohol part based on the '-yl' name.
- Connect both the alcohol and acid parts.