氟改性UiO-66固载钼基过氧化物催化氧化含硫化合物

采用预修饰方法对UiO-66进行配体官能团改性, 通过引入—F调控UiO-66的表面亲疏水性质; 其次, 通过引入—NH₂在UiO-66骨架上锚定MoO(O₂)₂. 接触角测试表明, 氟的引入有效地提高了载体表面的疏水性; 热重分析证明, 氟修饰的UiO-66骨架上存在更多配体缺失, 从而有效提高了整体MOF骨架的Lewis酸性. 以二苯并噻吩(DBT)氧化为氧化脱硫模型反应, 过氧化氢异丙苯(CHP)为氧化剂, 采用正交实验考察了反应温度、 氧硫比及催化剂用量对催化性能的影响, 其中氧硫比是影响DBT转化率的决定性因素. 经过氟改性后的催化剂经过5次催化反应循环后其催化活性未见明显变化, 且骨架仍保持稳定.

Molybdenum Peroxide Anchored on Fluoronated UiO-66 as Catalyst in the Oxidation of Sulfur Containing Compounds

The oxidative desulfurization（ODS） process is a very important tool to reduce sulfur emission and to comply with the increasingly stringent environmental regulations for fuels. Metal-organic frameworks with high specific surface area can introduce the 2nd metal sites via. chemical bonding， thus constructing a heterogeneous catalytic system with good chemical stability， which has advantages in the field of liquid-phase oxidative desulfurization. In this work， the ligand functional groups of UiO-66 were modified by pre-modification. Firstly， the hydrophilic and hydrophobic properties of UiO-66 were regulated by introducing —F； secondly， MoO（O₂）₂ was loaded on the UiO-66 framework by introducing —NH₂. The contact angle test showed that the introduction of fluorine effectively improved the hydrophobicity of the carrier surface， and thermogravimetric analysis proved that there were more ligand missing on the fluorine-modified UiO-66 framework， thus effectively improving the Lewis acidity of the overall MOF framework. The effects of reaction temperature， ratio of oxygen to sulfur and catalyst dosage on catalytic performance were investigated by orthogonal experiment with dibenzothiophene（DBT） oxidation as the model reaction and cumene hydroperoxide（CHP） as the oxidant. The results show showed that O/S molar ratio is the key factor affecting DBT conversion. The catalytic activity of the fluorine modified catalyst has no obvious change after five catalytic cycles， and the framework remains stable.