Characterization and analysis of the triglyceride transesterification process

Nuclear magnetic resonance (NMR) spectroscopy has been employed to study the triglyceride transesterification process and characterizes the triglyceride, fatty acid methyl esters, and valorized products from biodiesel waste. Detailed NMR studies such as ¹H, ¹³C, DEPT-135, HMBC (¹H-¹³C), HMQC (¹H-¹³C), and COSY (¹H-¹H) have been performed to analyze the transesterification reaction mixture and the products. Both unused sunflower oil and used sunflower oil (waste cooking oil) were used as a triglyceride source for transesterification reaction. Zero-waste valorization of biodiesel waste is successfully demonstrated and the low-value byproduct is purified into a high-value glycerol product. Neutralization of the byproduct with hydrochloric acid produces a significant amount of salt that has been separated, washed with an organic solvent, and recrystallized to white crystalline potassium chloride. Free fatty acids and fatty acid esters have also been isolated from the acidified byproduct and utilized for surfactant preparation. Reduced pressure distillation of the aqueous glycerol layer followed by passing the distilled liquid through the resin column resulted in an odorless transparent viscous liquid. The zero-waste valorization of biodiesel waste realizes a holistic approach for resource management and sustainable development for future generations.