Acid anhydrides Flashcards
What is an acid anhydride made up of?
Two identical carboxylic acids
What do the two carboxylic acids join up by?
Via an oxygen molecule with the carbonyl groups on either side
What is released when two carboxylic acids join up?
A molecule of water
How do you name an acid anhydride?
Take off “acid” and add “anhydride”
What do you get when you react an acid anhydride with water?
2 carboxylic acid molecules
What do you get when you react an acid anhydride with methanol?
Ester
Carboxylic acid
What do you get when you react an acid anhydride with ammonia?
Amide
carboxylic acid
What do you get when you react an acid anhydride with an amine?
N-Substituted amide
Carboxylic acid
Why are reactions with acid anhydrides better than reactions with acyl chlorides?
They’re almost the same but they are less vigorous and a carboxylic acid is formed instead of HCl
How can you make aspirin?
Salicylic acid and either ethanoic anhydride or ethanoyl chloride
Why is ethanoic anhydride used over ethanoyl chloride?
Cheaper
Safer as its less corrosive, reacts more slowly with water and doesn’t produce dangerous HCl fumes
What is aspirin?
A type of ester
