probably cold ethanol dissolves more of the soluble impurities than cold water, so you get more soluble impurities removed. since ethanol is a better solvent than water (but both don't dissolve the crystals)
After my hot acidic filtration under reduced pressure my crystals failed to form, I tried scratching the sides to no avail and even leaving it overnight does not form crystals, any idea what I can do to form crystals from the pure aspirin dissolved in ethanol?
ik it's a year later, but in the first step, i don't think you should dissolve the aspirin in hot acid, it should be dissolved in hot ethanol. maybe that's why the crystals didn't reform?
Excellent explanation of the single recrystallization. Do you do weighings of the tared, dried product at each step for % yield?
Excellent video. Your explanations and the summary was perfect. Many thanks.
Thank you.
NP
Hello, if the point of the cold filtration was to not dissolve the crystals, why do we still have to use ethanol rather than simply water?
probably cold ethanol dissolves more of the soluble impurities than cold water, so you get more soluble impurities removed. since ethanol is a better solvent than water (but both don't dissolve the crystals)
After my hot acidic filtration under reduced pressure my crystals failed to form, I tried scratching the sides to no avail and even leaving it overnight does not form crystals, any idea what I can do to form crystals from the pure aspirin dissolved in ethanol?
ik it's a year later, but in the first step, i don't think you should dissolve the aspirin in hot acid, it should be dissolved in hot ethanol. maybe that's why the crystals didn't reform?