Carboxylic Acids and Derivatives: Acylation - Acid Anhydrides Flashcards
How are acid anhydrides formed?
- Formed from two identical carboxylic acid molecules
- The two carboxylic acid molecules are joined together by an oxygen with the two carbonyl groups on either side
- The oxygen comes from the OH group of one of the carboxylic acids
- The other OH and H are released as water
What is the suffix for acid anhydrides?
- -oic anhydride
- Naming like carboxylic acids
Which substances do you need to know about that react with acid anydrides?
- Water
- Alcohol
- Ammonia
- Primary amines
What is always formed in reactions between acid anhydrides and water/alcohol/ammonia/primary amines?
- Carboxylic acids
Give the general word equation for the reaction between acid anhydrides and water
- Acid anhydride + water → 2 carboxylic acids
Give the general word equation for the reaction between acid anhydrides and alcohols
- Acid anhydride + alcohol → ester + carboxylic acid
Give the general word equation for the reaction between acid anhydrides and ammonia
- Acid anhydride + ammonia → amide + carboxylic acid
Give the general word equation for the reaction between acid anhydrides and amines
- Acid anhydride + amine → N-substituted amide + carboxylic acid
Which is more favoured in industry in the manufacture of aspirin: ethanoic anhydride or ethanoyl chloride?
- Ethanoic anhydride
Why is ethanoic anhydride favoured in industry in the manufacture of aspirin?
- Ethanoic anhydride is cheaper
- Safer - less corrosive, reacts more slowly with water, doesn’t produce dangerous hydrogen chloride fumes
What is the functional group of an amide?
- RC(=O)NH2
What are N-substituted amides?
- Have at least one alkyl or aryl group bonded to the nitrogen, instead of hydrogen atoms
How do you name N-substituted amides?
- E.g N-methylethanamide CH3C(=O)NHCH3
- N-methyl - methyl (CH3) is bonded to nitrogen
- Eth(an-) - 2 carbons in acyl group
- Acyl group - RC(=O)-
What is the functional group of an amine?
- RNH2
