Low-temperature catalytic oxidative desulfurization by two-phase system with O-bridged diiron perfluorophthalocyanine

An environmentally friendly desulfurization technology was constructed innovatively through coupling extraction and oxidation technique under mild conditions. A biomimetic catalytic system was built by O-bridged diiron perfluorophthalocyanine (FePcF 16 -O-FePcF 16 ) and hydrogen peroxide, and its displayed excellent catalytic activity and satisfactory regenerative performance for the oxidative desulfurization reaction. A mixed solvent of ethanol and water (volume ratio 9:1) was used as a “green” extractant with the property of low cost and low toxicity. It was found that 99% of the conversion rate of dibenzothiophene was achieved successfully after 2 h operation at 30 °C. The catalyst system was cycled 6 times without significantly reducing the removal of DBT. The catalytic activity was in the order of dibenzothiophene > 4,6-dimethyldibenzothiophene > benzothiophene. In addition, a possible reaction mechanism of the extraction and oxidative desulfurization was proposed and confirmed by electron paramagnetic resonance tests, gas chromatograph-mass spectrometer and electrospray ionization–mass spectrometry. The results demonstrated that the high-valent iron-oxo (Fe(IV) = O) was the main active species and this technology provides a novel idea for the design of high-efficiency, energy-saving and environmentally friendly desulfurization system.