Esters Flashcards
Define an ester
An ester is formed when a carboxylic (alkanoic) acid molecule reacts with an alcohol (alkanol) molecule in a condensation or esterification reaction.
When naming, what is first part of name
Alcohol molecule (alcohol to alkyl)
When naming, what is second part of name
Carboxylic acid (acid to alkanoate)
3 uses of esters
-Give sweets flavour
-Ethyl benzanoate in perfumes
-Solvents for nonpolar solutes (solvents for nail varnish)
Why are esters good for the uses
They are very volatile (evaporate easily)
Catalyst for esterification (condensation)
Concentrated sulfuric acid
Define condensation/esterification
A reaction where a molecule of water is eliminated as two molecules join together
How to tell which is alcohol and which is acid in an ester
Alcohol takes C - O
Acid takes C = O
Ester link
Circle the O between the alcohol and acid
Define hydrolysis
The splitting of a molecule by reaction with water
Is esterification reversible or irreversible
reversible
What will hydrolysis of an ester produce
Parent alcohol + acid
Apparatus for heating under reflux
Heating mixture with a condenser attached
Define acid hydrolysis and is it reversible
when esters are heated under reflux with an acid catalyst and the hydrolysis is reversible
Define alkaline hydrolysis
when esters are heated under reflux with an alkali and the reaction goes to completion
Stage 1 alkaline hydrolysis
Reversible - acid and alcohol produced
Stage 2 alkaline hydrolysis
Alkali reacts with carboxylic acid formed in a neutralisation reaction and so is no longer reversible
How to identify when an ester is formed
Distinctive smell and oil layer forms
Why use a condenser
Prevent escape of gas reactants
Safe methods heating flammable mixture
Hot water bath
Heating mantle
other product when ester formed
water
how to draw salt for carboxylic acid
Remove hydrogen from singly bonded O
Add element next to O (no bond)
Typical isomer of esters
carboxylic
