Sciencemadness Discussion Board

Anthranilic Acid crystals turn dark. Why?

vibbzlab - 12-2-2022 at 21:54

I had made some Anthranilic Acid crystals as part of my organic chemistry research. initially it was pure white after recrystallisation. But later it turned brown. Why does this color change occur?

DraconicAcid - 12-2-2022 at 22:09

It oxidizes in air.

Amos - 13-2-2022 at 06:53

Every aniline derivative does this. The oxidized impurity is very potent in color and just a miniscule amount will discolor the whole batch, and thus a dark color doesn't really mean anything about the purity of your anthranilic acid. It's good to use still. In the future try to look around on the forums first rather than starting a new thread; I know we've had this same conversation on the board multiple times in the last couple of years.

[Edited on 2-13-2022 by Amos]

draculic acid69 - 17-3-2022 at 04:41

Look for other recent threads on anthranillic acid. One uses a soxelt extractor and heptane to purify it instead of water and it came out sparkly white. It seems that as soon as water is used for recrystallisation it goes brown. Try making it again and don't recrystallize in water.