[McCoy]

why is activated charcoal added to a cold solution then heat the solution to boiling rather than adding activated charcoal to a boiling solution?
what i know is that charcoal sucks up impuries in the crude compound.
help please.
thank you.

[McCoy]

oh I got it...the solution will boil over, i guess?

[ARGOS++]

Dear McCoy;

Your conclusion is correct!,  -  But your procedure is wrong!

During crystallisation you normally DON’T add the Activated Charcoal (AC) to the cold solution, because then you are not able to control the amount of required solvent by eye at boiling temperature!

The usual procedure goes approximately like this:

• a.)   Mix your product with ~1/4 of the expected amount of solvent and start to heat.
• b.)   At the boiling point add quite slowly solvent till just all product is dissolved under boiling condition.
• c.)   Let the solution cool approx. 10°C below the boiling point and then add slowly the AC. 
         Doing this way the solution will not boil over.
• d.)   Heat again to the boiling point and then filter the hot solution.
• e.)   . .

I hope to have been of help to you.
Good Luck!
                    ARGOS⁺⁺

[McCoy]

oh thank you very much.i hope that explain why my acetanilide has brown tint haha.I added ac when the solution was boiling! I can't be a good analytical chemist:(.too bad.