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Chemistry

Naming organic compounds

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Naming carboxylic acids and esters

Carboxylic acids

Carboxylic acids contain the carboxyl functional group (-COOH). The carboxyl group will never have a position number in a carboxylic acid, as it is always on the end of the carbon chain.

Carboxylic acids end in '-oic acid'.

The basic rules of naming apply.

For example:

Structures of methanoic acid (CH=OOH) 2-methylpropanoic acid (CH3-CHCH3-COOH, 3-methylpentanoic acid (not 2-ethylbutanoic acid, CH3-CH2-CHCH3-CH2-COOH)

Esters

An ester is made from an alcohol and a carboxylic acid.

Esters have their own rules for naming.

The first part of the name comes from the alcohol, and it ends with the letters '-yl'.

The second part of the name comes from the carboxylic acid, and it ends with the letters '-oate'.

For example:

Name of AlcoholName of Carboxylic acidName of ester
ethanolpropanoic acidethyl propanoate
butanolmethanoic acidbutyl methanoate
pentanolethanoic acidpentyl ethanoate

It is also possible to form names from structures.

The ester is divided between the carbon and oxygen in the ester functional group.

The acid part contains the carbonyl group.

The division of the acid part and alcohol part that make up the ester ethyl butanoate are shown by the division between the carbon and oxygen of the ester functional group

For example:

Structures of methyl propanoate, ethyl ethanoate and butyl methanoate

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