In this work, the oxidation mechanism of thiophenic compounds over Ti-MWW zeolite was investigated by DFT-D3 method. Formation energy and activation barrier results indicate that Ti1-η²–OOH–H₂O is the most likely to be the real active center. It was revealed that the reactivity increased in the order of thiophene < benzothiophene < dibenzothiophene < 4-methyldibenzothiophene < 4, 6-dimethyldibenzothiophene, generally consistent with the previous experimental and theoretical results. Independent gradient model analysis suggests a strong interaction between O_α and S in transition states, clearly explaining why the oxidation products could be formed readily. At last, the kinetics results show that oxidation desulfurization on Ti-MWW could easily occur at room temperature. The findings can contribute to a better understanding of the oxidative desulfurization mechanism of thiophenic compounds on Ti-MWW zeolite.

本工作采用DFT-D3法研究了噻吩类化合物在Ti-MWW沸石上的氧化机理。形成能和活化能垒结果表明 Ti1-η ² -OOH-H ₂ O 最有可能是真正的活性中心。结果表明，反应性按噻吩<苯并噻吩<二苯并噻吩<4-甲基二苯并噻吩<4, 6-二甲基二苯并噻吩的顺序增加，与之前的实验和理论结果基本一致。独立梯度模型分析表明 O _α之间存在强相互作用和 S 处于过渡态，清楚地解释了为什么容易形成氧化产物。最后，动力学结果表明，Ti-MWW 在室温下很容易发生氧化脱硫。这些发现有助于更好地理解噻吩化合物在 Ti-MWW 沸石上的氧化脱硫机理。