Photochemical Oxidation of Thiophene Adsorbed on Na-ZSM-5 Zeolite by O2 in Oil/Acetonitrile Two-Phase Extraction System

Photochemical oxidation of thiophene in n-octane/acetonitrile extraction system using O₂ as oxidant was studied. Results obtained here can be used as the reference for the oxidative desulfurization of gasoline because thiophene is one of the main components containing sulfur in fluid catalytic cracking gasoline. A 500 w high-pressure mercury lamp was used as light source for irradiation and air was introduced by a gas pump to supply O₂. Thiophene dissolved in nopolar n-octane solvent was photodecomposed and removed into the polar acetonitrile phase. The desulfurization rate of thiophene in n-octane is 65.2% under photo-irradiation for 5 h. It can be improved to 96.8% by adding 0.15 g Na-ZSM-5 zeolite into 100 mL reaction system, which is the absorbent for O₂ and thiophene. And the photooxidation kinetics of thiophene with O₂ and Na-ZSM-5 zeolite is first-order with an apparent rate constant of 0.6305 h^-1 and half-time of 1.10 h under the conditions of air flow at 150 mL-min^-1 and V(n-octane): V(water)=1:1. The sulfur content can be depressed from 800 muL-L^-1 to less than 26 muL-L^-1.