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用沉淀法制备了 L i3PO4 、Fe PO4 和 5% L i3PO4 ·Fe PO4 3种固体表面材料 ,并用 XRD、IR、TPD和激光促进材料表面反应 ( L SSR)等技术研究了在这些化合物固体表面上甲醇氧化偶联生成乙二醇的反应规律 .结果表明 :甲醇在催化剂表面的 P O 键上产生 C— H端的分子态吸附 ,在表面的 L ewis酸位上产生解离态吸附 .L i3PO4 和 Fe PO4 的相互作用可影响甲醇在固体表面的吸附态 .激光表面反应的机理为 :用频率为 10 77cm-1的激光光子激发固体表面的 P O 键 ,可使表面晶格氧活化 ,活化的氧与吸附态的甲醇分子作用使其脱氢 ,形成表面 CH2 OH基 ,进而在固体表面的 L ewis酸位上 CH2 OH基相互偶联生成乙二醇 .反应温度的提高有助于补充激光能量的不足 ,同时促进产物的脱附 ,但温度升高会诱发热反应进行而生成副产物
Three kinds of solid surface materials, L i3PO4, Fe PO4 and 5% L i3PO4 · Fe PO4, were prepared by precipitation method. The effects of XRD, IR, TPD and LPSR on the surface of these compounds were investigated. The results showed that the methanol adsorbed on the PO bond on the surface of the catalyst resulted in the molecular absorption at the C-H end, which resulted in the dissociative adsorption on the Lewis acid sites on the surface of the catalyst.Li3PO4 and Fe PO4 interaction can affect the methanol adsorption state on the solid surface.Laser surface reaction mechanism is: the frequency of 10 77cm-1 laser photons on the solid surface PO bond, the surface lattice oxygen can be activated, activated oxygen and Adsorption of methanol molecules to dehydrogenation, the formation of surface CH2 OH groups, and then in the solid surface Lewis acid acid sites CH2 OH coupling with each other to generate ethylene glycol.Reaction temperature helps to supplement the lack of laser energy , While promoting the desorption of the product, but the temperature will induce the thermal reaction proceeds to produce by-products