goxingyi - 7-9-2006 at 03:57
how to recrystallize 2-Chloro-1H -benzimidazole?
thanks lot.
12AX7 - 7-9-2006 at 07:56
Uh...dissolve in...alcohol!?
Seems to me it may be soluble in water too...
Then remove solvent, or precipitate with different solvent.
Was that especially hard, goxingyi?
Tim
garage chemist - 7-9-2006 at 08:20
12AX7, that's not how one recrystallizes something!
Adding solvent and then removing it reduces purity instead of increasing it.
Same for adding another solvent to precipitate something from solution. This is not a method to purify chemicals.
Recrystallizing is dissolving the substance in a hot solvent, letting it cool and then filter the crystals.
Impurities that have the same solubility as the substance can be removed by this, since they stay in solution because their concentration is too
small.
@ threadstarter: Please look for a solvent in which your substance has moderate solubility, and then do what I've said about recrystallization.
12AX7 - 7-9-2006 at 11:18
Well...obviously you remove the crystals and leave the impurities in the rest of the liquor...
As far as I know, this works as well as cooling, if not moreso for chemicals with a small temperature difference in solubility (e.g., salt).
Tim