Abstract:

A cationic surfactant 2C₁₂GeQS was prepared by amidation reaction and quaternization reaction. The molecular structure of the cationic surfactant was characterized by infrared spectroscopy and ¹H NMR. Then 2C₁₂GeQS was used as the phase transfer catalyst to conduct a single factor experiment in the oxidative desulfurization of straight-run diesel. The results showed that the surfactant 2C₁₂GeQS was successfully prepared, and the presence of amide group was confirmed by the IR peaks at 1 641 and 1 550 cm^-1. The optimized reaction condition for oxidative desulfurization of straight-run diesel was as follows: The reaction temperature was 60 ℃, the reaction time was 90 min, the stirring rate was 900 r/min, the surfactant dosage was 0.2wt%, the volume ratio of H₂O₂ and CH₃COOH in oxidizing system was 0.7, and the volume ratio of oxidizer to diesel was 0.3. Under this condition the desulfurization rate and mass yield of diesel were 85.96% and 94.28%, respectively. With the increase of the number of cycles, the pore structure of the surfactant 2C₁₂GeQS was gradually blocked, and agglomeration phenomenon was observed at the surfactant surface, and the desulfurization ability of the surfactant was gradually reduced. After five cycles, the desulfurization rate and mass yield were 82.89% and 90.05%, respectively, indicative of high desulfurization effect and excellent reusability.

Key words: straight-run diesel, oxidative desulfurization, quaternary ammonium cationic surfactant, phase transfer, catalyze