水溶液pH对甲烷低温氧化制备甲醇的影响

采用固态离子交换法制备了Fe/ZSM-5催化剂, 并通过X射线粉末衍射(XRD)、 电感耦合等离子光谱(ICP)、 漫反射紫外-可见光谱(DR UV-Vis)、 拉曼光谱(Raman)和固体核磁共振波谱(Solid-state NMR)表征方法对催化剂的结构和相关物理性质进行了表征. 采用H₂SO₄和NaOH调控反应体系的pH, 并通过气相色谱和液体核磁共振波谱分别对气相和液相产物进行定量分析, 研究了不同水溶液pH对反应活性的影响. 并对不同pH下Fe/ZSM-5催化剂的金属析出量以及剩余H₂O₂浓度的影响进行了研究. 上述结果为进一步优化甲烷低温氧化制备甲醇的反应提供了指导思想.

Effect of Aqueous Solution pH on the Oxidation of Methane to Methanol at Low Temperature

This study investigated the effect of different aqueous solution pH on the reactivity of the Fe/ZSM-5 zeolite in the process of selective oxidation of methane to methanol using H₂O₂ as oxidant at low temperature. Fe/ZSM-5 catalyst was prepared by solid ion exchange method， and its structure and physical properties were characterized by means of X-ray diffraction（XRD）， inductively coupled plasma（ICP）， diffuse reflectance ultraviolet/visible spectroscopy（DR UV-Vis）， Raman spectroscopy（Raman）， and solid-state nuclear magnetic resonance（Solid-state NMR）. H₂SO₄ and NaOH were used to adjust the pH of the reaction solution， and the products were quantitatively analyzed by gas chromatography and liquid NMR. The influences of different aqueous solution pH on the reactivity of the reaction were systematically investigated. Besides， the effects of the aqueous solution pH on the metal leaching out of the Fe/ZSM-5 catalyst and the residual concentration of H₂O₂ were further investigated. It is expected that the obtained experimental results could provide guidance for further optimization of the selective oxidation of methane to methanol reaction.