Esters Flashcards
What is an esterification reaction?
Alcohols and Carboxylic acids reacting together to make esters
What is the functional group of esters?
-COO-
Are esters compounds?
Yes
What two things are esters used in?
Food Flavourings and Perfumes
How is ethyl ethanoate formed?
Ethanoic acid will react with ethanol in the presence of concentrated sulfuric acid (catalyst) to form the ester ethyl ethanoate
What features do esters have?
They are sweet smelling oily liquids
What else is produced in an esterification reaction?
A molecule of water (H2O)
What are esters made from?
Carboxylic acids reacting with an Alcohol
What does an ester’s name always end with?
-anoate
When naming an ester, what always takes the first part of the name?
The alcohol
When naming an ester, what always takes the second part of the name?
The carboxylic acid
Carboxylic acid + Alcohol ——>?
Ester + Water
What is the water molecule made of during an esterification reaction?
The OH- ion from the carboxylic acid AND the H+ ion from the alcohol
When drawing the displayed formula of an ester, what element joins the carboxylic acid and the alcohol?
An oxygen ion (O) from the end of the carboxylic acid which bonds with the end carbon (C) ion in the alcohol
What is the structural formula of ethyl ethanoate?
CH3CO2CH2CH3
Where is the double bond in an ester?
In the carboxylic acid between a carbon (C) and oxygen (O) atom
What is the purpose of an acid catalyst in an esterification reaction?
To speed up the reaction (usually use concentrated sulfuric acid)
What other term can be used to refer to the -COO- group in esters?
Ester link
What is the only byproduct of an esterification reaction?
The water molecule (H2O)
What is the structural formula of ethanoic acid?
CH3COOH
What is the structural formula of ethanol?
CH3CH2OH
Can you draw the displayed formula for ethyl ethanoate?
DRAW IT RIGHT
What is the name of the ester that is formed by ethanol and propanoic acid?
Ethyl propanoate
What is the name of the ester that is formed by butanol and methanoic acid?
Butyl methanoate
What is the name of the ester that is formed by pentanol and ethanoic acid?
Pentyl ethanoate
What other reaction can an esterification reaction be described as?
The reaction can also be described as a condensation reaction because water is made when two molecules join together
What is ethyl ethanoate?
An ester
What kind of compounds are esters?
They are volatile compounds with distinctive smell and are used as food flavourings and in perfumes
What kind of smell are esters often described as having?
Esters are often described as having a sweet, fruity smell (they typically smell of bananas, raspberries, pears or other fruit because esters occur in all these natural products)
How would you prepare a small sample of ethyl ethanoate?
METHOD:
-obtain a test tube and add 6 drops of sulfuric acid to it
-add 10 drops of ethanol to the same test tube
-carefully add 10 drops of glacial ethanoic acid to the same test tube
-gently warm the test tube in a water bath for a few minutes (ETHANOL IS FLAMMABLE SO A BUNSEN BURNER CANNOT BE USED)
-obtain a 100cm3 beaker and measure approximately 25cm3 of sodium carbonate solution and pour into the beaker (to remove acidic impurities)
-tip the contents of the test tube into the beaker, swirl gently and smell carefully by wafting fumes towards your nose from a distance of about 20cm
