核黄素光敏氧化噻吩脱硫研究

Photosensitized oxidative desulfurization of thiophene by riboflavin

以噻吩的正辛烷溶液模拟FCC汽油,以水为萃取剂,以空气中的O2为氧化剂,以核黄素为光敏剂,研究了噻吩在500W高压汞灯照射下的光化学氧化。实验结果表明,在通气量为150mL/min、水油比为1∶1、核黄素加入量为30μmol/L的条件下,反应3h后噻吩的脱硫率能够达到85.4%。核黄素的敏化作用是通过激发基态氧为单线态氧实现的,噻吩氧化脱硫为一级动力学反应,加入光敏剂时反应速率常数k=9.10×10-5s-1,半衰期t1/2=2.12h。

Photosensitized oxidative desulfurization of thiophene in n-octane/water extraction system was studied with riboflavin as photosensitizer and O2 in air as oxidant. A 500 W high pressure Hg lamp was used as the light source for irradiation and air was introduced by a gas pump for supplying O2. The desulfurization yield of thiophene was 85.4% for a 3 h photoirradiation under the conditions with the air flow at 150 mL/min, water/oil ratio at 1： 1 and riboflavin concentration at 30 μmol/L. The mechanism of photosensitized oxidative of thiophene is ^1O2 exited from ^3O2 by the addition of riboflavin. Under the above conditions, the photooxidation kinetics of thiophene with O2/riboflavin is first-order with a rate constant of 9.10 ×10^-5s^-1 and half-time of 2.12 h.