I've already posted about my project multiple times and here I go again.
Basically now that I have managed to isolate caffeine from energy drinks I am trying to purify it.
This is my method:
The crude caffeine is washed with 1 ml portions of a 1:1 mix of hexane and diethylether.
The liquid is removed using a pipette.
The caffeine is dissolved in 2 ml of dichloromethane.
This is filtered through a thin layer of cotton into a test tube and the dish is washed a couple times with small portions of dichloromethane.
The test tube is placed in a water bath at 50-60°C
After the solvent evaporates isopropyl alcohol is added drop wise till the caffeine dissolves.
The test tube is removed from the water bath and allowed to cool to room temperature.
1 ml of hexane is added to the test tube causing the caffeine to crystallise.
The liquid is removed using a pipette and the caffeine is washed with small portions of a 1:1 mix of hexane and diethyl ether. This is removed using a pipette.
The caffeine is left to dry.
Everything goes pretty well for the most part, When adding the isopropyl alcohol I could see some nice crystals of caffeine, however, after it dissolves and the hexane is added very little crystallises.
Is this due to something I'm overlooking or is it better to stop the purification a bit earlier like just before adding isopropyl alcohol?
I am generally quite inexperienced so I would not be surprised if it's something very simple.