Practical 10b: Synthesis and Purification of Ethyl Ethanoate Flashcards
what are anti bumping for
prevent large bubbles from forming
prevents vigorous bubbling
why isn’t a bunsen burner used as a heat source?
ethanol is flammable
why is the cold water entering the condenser from the bottom rather than the top?
to completely fill the condenser with cold water
why is it essential to have an open top at the top of your condenser?
to prevent pressure from building up
why is sodium carbonate used to wash the mixture?
to react and remove any excess ethanoic acid which would be a contaminant
why is the stop cock repeatedly opened after every inversion?
to prevent pressure from building up
what is the point in adding anhydrous calcium chloride/sodium sulfate to the washings?
to remove unwanted water
why is the aqueous layer below the organic layer?
its more dense
name the process that we purify the ester
distillation
why would the ester have a lower boiling point than the starting ethanoic acid and ethanol starting materials?
no hydrogen bonding between molecules
why should the end of the thermometer be level with the condenser?
to accurately measure the boiling point of the vapour
how can we qualitatively observe at an ester has been made?
fruity smell
what is the boiling point of ethyl ethanoate ?
77.1 degrees C
why is sodium carbonate added to reaction mixture in separation of products?
This neutralises the unreacted acids
helps to separate the ester into an oily layer
two reasons stopcock opened
The separating funnel is inverted and the stopcock opened to release the pressure
The stop cock is opened so that the aqueous layer drains away and then the ethyl ethanoate can be drained into a clean beaker
why is sodium sulfate added during separation
to absorb water and dry the ethyl ethanoate
how is product separated
immiscible layers separate
hazards
- ethanol is flammable
- ethyl ethanoate is toxic , flammable + has a strong odour, should be handled in fume cupboard
how can an ester be identified
using bp of ester
, or smell
ester can then be hydrolysed and the resulting carboxylic acid purified by recrystallisation and its melting pint checked against known values
The acid hydrolysis of an ester is very slow, how can the process of formng the c acid be sped up
The acid hydrolysis of an ester is very slow,
so it must be heated under reflux with an acid catalyst to make the carboxylic acid
