甲醇脱氢和选择氧化制备甲酸甲酯的催化剂与反应路径

Catalysts and reaction pathways for dehydrogenation and selective oxidation of methanol to methyl formate

甲酸甲酯是重要的化学中间体.围绕甲酸甲酯的高效制备,本文总结了甲醇脱氢和选择氧化2种方法所使用的金属和金属氧化物催化剂的结构与其催化性能之间的关系以及所涉及的反应路径,分析了影响反应路径和甲酸甲酯选择性的关键因素.这些认识将有助于设计和构筑具有特定结构和功能的金属氧化物、贵金属以及贵金属-金属氧化物复合催化剂,从而实现甲醇到甲酸甲酯的高效定向转化.

Methyl formate is a versatile chemical precursor to a wide range of other important chemicals. It can be synthesized by different routes, among which dehydrogenation and selective oxidation of methanol to methyl formate are particularly attractive, because they are operationally simple and green. Metal catalysts such as Cu and Pd-Zn alloys show good performances in the dehydrogenation reaction, and metal oxides such as Mo O3-Sn O2 and Ru Ox/Zr O2, noble metals such as Au and Pd, and their composites, are widely used in the selective oxidation of methanol. We focused on the efficient synthesis of methyl formate, and determined the relationship between the catalyst structures and properties, and the reaction pathways in the dehydrogenation and selective oxidation of methanol. The main factors affecting the reaction pathways and selectivity for methyl formate are discussed in detail. The structures of the formaldehyde species adsorbed on Cu and Pd-Zn alloys surfaces play essential roles in the product selectivities in the dehydrogenation reaction. The secondary reaction rates of the formaldehyde intermediates on supported oxide catalysts and the reactivities of adsorbed oxygen species on noble metals control the selectivities of the methanol selective oxidation. These fundamental insights provide a basis for the design of novel catalysts with specific structures and functions for more efficient conversion of methanol to methyl formate.