Advanced Organic - Acyl anhydrides & Acid anhydrides (7.2) Flashcards
What functional group do esters contain?
COO group in the middle of the chain (C=O bond and attached to this C, an O is also bonded)
How can you distinguish esters from other compounds?
They are neutral compounds with a sweet/fruity or distinctive smell
What happens in esterification?
Alcohol + carboxylic acid -> ester + water
condensation reaction
What are the conditions required for esterification?
An acid catalyst e.g H2SO4
Give an advantage when using carboxylic acids for esterification
Non-toxic reagents & products
Give a disadvantage when using carboxylic acids for esterification
It is a reversible reaction so will not give 100% yield
How are acyl chlorides synthesised?
Carboxylic acid + phosphorus pentachloride (PCl5)
No conditions
What type of reaction is nucleophile (Nu) + acyl chloride?
A (nucleophilic) addition-elimination reaction
Give 2 examples of other homologous series that undergo a similar reaction mechanism to the addition-elimination reaction between Nu + acyl chloride when they react with a nucleophile
acyl chlorides acid anhydrides amides amino acids carboxylic acids
Give an advantage of using acyl chlorides for esterification
- 100% yield
- Acyl chlorides are extremely reactive so do not require a catalyst
Give a disadvantage of using acyl chlorides for esterification
- Production of toxic fumes of acidic HCl in the process
- Very dry conditions required
Acyl chlorides are extremely reactive so they can react with moisture in the air. What products are made from this reaction?
Carboxylic acids & misty fumes of acidic HCl gas
Acid anhydrides only be symmetrical. True or false?
False - They can be symmetrical or asymmetrical
Symmetrical acid anhydrides produce two molecules of the same carboxylic acid. True or false?
True - asymmetrical acid anhydrides produce two different carboxylic acids
