Solubility, metastable zone, and cooling crystallization process of dodecanedioic acid investigated by focused‐beam reflectance measurement technology

Abstract BACKGROUND Dodecanedioic acid (DC 12 ) is widely used as a chemical intermediate in nylon synthesis but its separation and purification are crucial for producing high‐quality DC 12 . Herein, the solubility characteristics of DC 12 in various solvents (ethanol, isopropanol, ethyl acetate, 1,4‐dioxane, Dimethyl sulfoxide (DMSO), and N , N ‐dimethylformamide (DMF)) were investigated by focused‐beam reflectance measurement technology. RESULTS Based on the results of solubility data simulation to the modified equations of Apelblat and λh , the former equation model of Apelblat yielded the best‐fitting performance. Subsequently, thermodynamic properties of DC 12 in the six solvents were investigated and the results identified increasing endothermic and entropy as the dissolution processes of DC 12 in all solvents. The thermodynamic analyses also revealed 1,4‐dioxane as the best solvent for the cooling crystallization of DC 12 . The measured metastable zone width (MSZW) of DC 12 cooling crystallization in 1,4‐dioxane displayed a decline as a function of the decrease in cooling rate and increase in stirring speed. CONCLUSION The optimal process parameters for the cooling crystallization of DC 12 in 1,4‐dioxane were determined as solid–liquid ratio of 1:5 g mL −1 , stirring speed of 200 rpm, and solution preparation temperature of 70 °C. To the best of our knowledge, the proposed method for crystallization of DC 12 with 1,4‐dioxane solvent is reported for the first time and has potential for future industrial application in DC 12 production. © 2025 Society of Chemical Industry (SCI).