Esters, Fats & Oils Flashcards
What is the functional group for an ester?
carboxylate (ester link) group (COO)
How do you name an ester?
The parent alkanol gives the start of the name in ‘yl’. The parent acid gives the second part of the name ending in ‘oate’
What are esters used for?
used as flavourings and fragrances. Esters are also used as industrial solvents.
How are esters made?
Esters are formed by the condensation reaction
between carboxylic acid and an alcohol. The ester
link is formed by the reaction of a hydroxyl group
and the carboxyl group. In condensation reactions,
the molecules join together with the elimination of a
small stable molecule, in this case water.
Is making esters a reversible or irreversible?
reversible
What are two advantages of using sulfuric acid when making esters?
acts as a catalyst, absorbs the water formed stopping the ester reacting w/ the water and prevents the reverse reaction
Are esters non-polar or polar molecules?
non polar
What is hydrolysis
large molecules are broken down into smaller molecules by the reaction with water
What is produced when esters are hydrolysed?
Esters can be hydrolysed to produce the parent
carboxylic acid and parent alcohol
What are the two types of hydrolysis of an ester?
Acid-catalysed hydrolysis
Alkaline hydrolysis
In acid catalysed hydrolysis, is the ester is heated with dilute HCl or H2SO4?
provides the H+ ions which catalyse the reaction
What are the products of Alkaline hydrolysis?
an alcohol and a salt of a carboxylic acid
How is alkaline hydrolysis carried out?
the mixture is heated under reflux, the alcohol is then distilled off. The remaining salt is acidified with HCl, converting it to the acid.
What are the advantages of alkaline hydrolysis?
It is not reversible, higher yield is obtained.
It is easier to separate the products
What are fats and oils?
Fats and oils are esters formed from the
condensation of glycerol (propane-1,2,3-triol) and
three carboxylic acid molecules. The carboxylic
acids are known as ‘fatty acids’ and are saturated
or unsaturated straight-chain carboxylic acids,
usually with long chains of carbon atoms.
