In this work the feasibility of continuous cloud point extraction in packed columns was evaluated. Therefore, extraction of phenylacetic acid with aqueous micellar two-phase systems containing the nonionic surfactant Triton X-114 was chosen as a model system. Raschig rings and structured packing CY from Sulzer were evaluated in terms of HETP, extraction efficiency and enrichment factor. Additionally, the product recovery from the micellar phase was addressed. Back-extraction via pH-shift and adsorption were evaluated to remove phenylacetic acid from the micellar phase, whereas the successful continuous back-extraction in a Kühni column was demonstrated. Finally, several process concepts to recycle the micellar phase and to further purify phenylacetic acid after back-extraction are suggested.
