Photochemical oxidation of thiophene by O2 in an organic two-phase liquid-liquid extraction system

Photochemical oxidation products and the kinetics of thiophene in an n -octane/acetonitrile extraction system using O 2 as an oxidant was studied. The results could be used as a reference for the oxidative desulfurization of gasoline because thiophene is one of the main components containing sulfur in a fluid catalytic cracking (FCC) gasoline. Thiophene dissolved in n -octane was photodecomposed and removed into the water phase at an ambient temperature and atmospheric pressure. A 500-W high-pressure mercury lamp (main wavelength 365 nm, 0.22 kW m −2 ) was used as the light source for irradiation and air was introduced by a gas pump to supply O 2 . Thiophene could be photooxidized to SO 4 2− and CO 2 . The desulfurization yield of thiophene in n -octane is 65.2% for a 5-h photoirradiation under the conditions of air flow at 150 m min −1 and V( n -octane): V(acetonitrile) = 1:1. It can be improved to 96.5% by adding 1.5 g L −1 artificial zeolite, which is an absorbent for O 2 . Under such conditions, the photooxidation kinetics of thiophene with O 2 is of the first order with an apparent rate constant of 0.6297 h −1 and a half time of 1.10 h. The sulfur content can be depressed from 800 to 28 ppm.