PRactical Flashcards
TCL method
grind the tablets using pestle and mortar dissolve in ethanol
Draw a line 1cm from bottom of plate and use a capillary tube to put sample.
Put small amount of ethyl ethanoate and place tlc plate and cover with lid
Considerations
Use dilute sample and too concentrate leaves spots as long streaks
Using a capillary tube
Large quantities of sample will cause spots as long streaks so use capillary tube
Why does the solvent line have to be below pencil line
The solvent will dissolve all the same and they will not travel up the plate
Why do solvent needs to be marked immediately?
As they evaporated quickly
Preparing crude aspirin?
Add weighed amount of salicylic acid and ethanoic anhydride and mix. Add sulphuric acid and warm mixture using water baths. Let it cool n pour in water and stir and and filter under reduced pressure and let it dry.
Recrystallisation of aspirin
Heat ethanol and add sprinin let it dissolve and
Why do we use ethanoic anhydride?
Less exothermic cheaper and easier to recycle. Less dangerous by product
Why dont we use acyl chloride?
HCl is produced dangerous
Preparing crude ethyl ethanoate
To a
