Transition Lessons Flashcards
What are the main uses of esters ?
Perfumes
Food flavourings
Solvents
Plasticisers
Why are esters used as perfumes.
They have low boiling points so vaporise easily to release a smell.
Why are esters often used over natural flavourings despite being artificial ?
They can be readily synthesised as they are cheap.
Whereas natural sources are much more expensive to extract.
How can esters and why can they be used as solvents.
They have low boiling points so evaporate reading.
Antibiotics , glue , nail varnish
How are esters used as plasticisers ?
Improve flexibility of plastics.
What is esterification ? And what type of reaction is this ?
Carboxylic acid reacts with an alcohol in the presence of a strong catalyst to form an ester and water.
It is a reversible condensation reaction
What are the issues with esterification and why ?
Has a low yield due to being a reversible reaction. The low yield is also caused as esters are highly volatile so much be collected by distillation.
Slow reaction
What are the other possible functional groups of esters ?
Acyl chlorides
Acid anhydrides
What are the products of a reaction of an acyl chloride.
Ester and hydrochloride acjd
What are the issues with using acyl chlorides to create esters ??
The products are esters and hydrochloric acid.
Hydrochloric acid is highly toxic and corrosive.
Acyl chlorides react violently with water so are hard to store.
What are the positives of a reaction with acyl chlorides to create esters ?
Fast reaction
Good yield- because it is irreversible.
What is the reaction of acid anhydrides ?
2 carboxylic acids react by condensation reaction to produce weak hydrochloric acid and an ester.
What are the positives of using acid anhydrides to create esters ??
They only produce a weak hydrochloric acid which is less harmful than hydrochloric.
They have a good yield due to it being an irreversible reaction.
What are the negatives of using acid anhydrides to create esters ??
Low atom economy
What are the negatives of using acid anhydrides to create esters ??
Produces a low atom economy
