Separation of Unsaturated and Saturated Fatty Acids from Sunflower Oil Via Low-Temperature Methanol Crystallization Method

Sunflower oil (SFO) is rich in unsaturated fatty acids which is more than 80%, making it suitable for diverse applications.The primary aim of this study was to separate the sunflower oil unsaturated fatty acids (SFOUFA) and sunflower oil saturated fatty acids (SFOSFA) from the mixture of sunflower oil fatty acids (SFOFA) using the low-temperature methanol crystallization method.This separation serves as a preparatory step for producing a biolubricant base stock, leveraging SFOUFA as the starting material.The separation process was executed with a fatty acid to methanol molar ratio of 1:15 (w/v), at a temperature of -15 C for 24 hours.Gas chromatography-mass spectrometry (GC-MS) was employed to determine the fatty acids composition of SFOUFA and SFOSFA, while Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) were utilized to characterize the separated compounds.The highest percentage of SFOUFA exceeded 98%, achieving a percentage yield of 85.72%, while the highest percentage of SFOSFA surpassed 99%, yielding 8.32%.The utilization of methanol as a solvent in low-temperature solvent crystallization was due to its notable attributes, including high efficiency, cost-effectiveness, stability, ready availability and ease of recovery.