Dissociation extractive crystallization is a two- or three-phase separation technique and exploits the differences between dissociation constants of the components and their chemical affinities towards extraneous agents. Separation of dichloroacetic and trichloroacetic acids was investigated through this process. In the two-phase method, the separation was carried out in aqueous phase using piperazine as a reagent. A ternary solid-liquid phase equilibrium diagram for the dichloroacetic acid-trichloroacetic acid-water system was constructed. The solubility of the trichloroacetic acid-piperazine complex was represented on the ternary diagram. In order to establish the separation feasibility, a series of batch and semibatch equilibrium precipitation experiments was performed at different concentrations and temperatures. At high concentrations, improved separation can be achieved in the semibatch operation. Using ternary equilibrium data, a general analytical equation for the maximum recovery of trichloroacetic acid as a function of feed concentration was proposed. High recovery and separation factor of trichloroacetic acid can be achieved in a single stage. In the three-phase process, di- and trichloroacetic acids were dissolved in toluene and aqueous piperazine solution was used as a reagent. Variations of the recovery and purity of trichloroacetic acid with the weight ratio of water to toluene were experimentally determined.