I synthesised [3,5 -bis(tolyl carbamoyl)phenyl pivalate] by reaction of 5-acetoxyisophthalic acid with para amino toluene and according TLC i have an exess of Para amino toluene. Moreover, i used DMAP and DIC as a catalyst.
Have you already tried aqueous acidic workup to get your paraaminotoluene protonated and therefore into the aqueous phase? This cour work well
yes i have tried but i added 0.1 N HCl until the medium became PH=6 so do you think this PH is not enough to remove it ?
Well, in general we use 1M sulphuric acid or a 2M HCl to remove anilin derivatives during our workup (for example in the synthesis of quite stable imins), I would give that a try. If you think this could be to strong you could try a saturated ammoniumchloride solution to wash you organic phase. Check all your phases by TLC to be sure were to find your impurities.
pH6 is indeed to high I would say, because pka of p-toluidine is 5.08, so you need a lower pH to significantly protonate you p-toluidine impurities
i agree with Rossen Buyukliev you can distill out para-amino toulene i did same process
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