Consists of a benzene ring with a
carboxylic acid functional group on
position 1, and an alcohol
functional group on position 2
2-hydroxybenzoic acid
Salicylic acid contains a phenol
group, so will not react with
Carboxylic acids to make esters,
hence why we use ethanoic
anhydride orethanoyl chloride to
make Aspirin.
Phenol groups can be detected by using
Iron (III) Chloride. If it goes dark purple then
there is a phenol group present. If it stays
orange then there is no phenol group.
Oil of Wintergreen
If Salicylic acid is reacted with
Methanol instead of an ethanoic
anhydride or ethanoyl chloride then it
forms oil of wintergreen, which also has
painkilling qualities.
Oil of Wintergreen is also an
ester, like Aspirin, however the
carboxylic acid functional group
has reacted this time, instead of
the alcohol group, so a different
ester is formed.
Ethanoic Anhydride
This is the most used
chemical to react with
salicylic acid to make
Aspirin.
Formed when 2 ethanoic acid
molecules react to form
ethanoic anhydride and water.
Condensation reaction
Ethanoyl Chloride
Formed when
ethanoic acid and
hydrogen chloride
react to form ethanoyl
chloride and water.
Substitution reaction
Not commonly used to react with
salicylic acid to make Aspirin as it
is a nasty chemical to handle.