AbstractFree fatty acids serve as fundamental precursors in surfactant synthesis, providing essential lipophilic structures for non-ionic and anionic surfactants. Despite the abundance of palmitic acid in palm oil, a highly efficient and straightforward synthesis of non-ionic surfactants using this free fatty acid remains unexplored. This work introduces a novel and facile method for synthesizing non-ionic surfactants via the reaction of palmitic acid with heterocyclic azoles, catalyzed by CuO-CeO2. The catalyst and synthesized surfactants – palmitic 1,3,4-thiadiazole, palmitic 1,3,4-oxadiazole, and their derivatives— are purified and compresively characterized in terms of their physicochemical properties, including particle size distribution, morphological structures, and crystallographic features. The synthesized surfactants are further applied in surfactant-assisted extraction of antioxidants from mangosteen peel (Garcinia mangostana L.) using an Aqueous Biphasic System (ABS) composed of PEG 6000 and ammonium sulfate (NH4SO4). Key extraction parameters, including surfactant concentration, partition coefficient, and recovery efficiency, are analyzed. UV/Vis characterization confirms successful synthesis, with palmitic 1,3,4-thiadiazole (10 mg, partition coefficient = 1.73) exhibiting the highest extraction efficacy. These findings highlight the potential of thiadiazole-based surfactants for efficient antioxidant extraction from natural sources, particularly fruit peels. Eventually, extracting natural antioxidants from various fruit peels promotes the circular economy by diminishing waste and creating value-added products. © 2026 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.