| dc.description.abstract | Industrial processes avoid the formation of azeotropic solvent solutions, because azeotropes cannot be recovered to pure solvents by distillation. If it is inevitable, additional processes may be required to recover the solvent and increase the operational costs. The potential advantage of azeotropic solvents in the crystallization process, that is, the azeotrope can be recovered after crystallization process by evaporation without worrying about changes in the co-solvent composition was proposed. In this thesis, six solvent systems, including acetone (ACE), ethyl acetate (EA), ethanol (EtOH), 2-propanol (IPA), the azeotropic mixture of EA/EtOH =70/30 wt% (AZE-EA/EtOH), and the azeotropic mixture of EA/IPA=75/25 wt% (AZE-EA/IPA), were investigated to separate and purify curcumin (CUR) from its structurally related impurities of desmethoxycurcumin (DMC) and bisdesmethoxycurcumin (BDMC) by cooling crystallization. The purified CUR crystals were harvested by filtration and drying at 40°C and the purity was determined by high performance liquid chromatography (HPLC). Utilizing the uniqueness of azeotropes, including AZE-EA/EtOH and AZE-EA/IPA can be recovered by evaporating the filtrate, then the ones of individual solvent components at a lower boiling point of azeotrope. The recovered azeotrope was analyzed by gas chromatography, and the boiling point and density at 25°C were measured at 1 atm to ensure the composition of the co-solvent. In my research, AZE-EA/EtOH is the most suitable solvent for CUR purification because of its high solubility power (28.8 mg/ml at 25°C) and solvent capacity (15.7 mg/ml), which has the advantage for solvent saving, and having almost the same purity about 94 wt% as EA and EtOH used in the food industry. Overall, the raw CUR of 71.8 wt% was purified to 94.4 wt% in AZE-EA/EtOH by one-step cooling crystallization, crystallization time was 1 day, and inoculation at 50°C and 300 rpm. | en_US |