I've done the following reaction:
Ar-NH2 with chloracetic acid in the following way:
3 g of acid was neutralized with 11-12 mL of NaOH 2N, aniline was added in portions (3 times) in about 2 or 3 minutes (3 mL) and reflux up to completion of the amine (in my case yellow layer of aniline), otherwise monitoring by TLC. (about 2 hours in my case). cooling (usually crystallization) and checking the pH (if it is basic correction with diluted acid) up to 7.
in my case works as charmed
good luck