我国富煤、少油和少气的能源结构决定了我国对煤炭资源具有极强的依赖性。因此,如何发挥我国大储量煤炭资源的优势,实现煤炭资源清洁化、低碳化和多元化利用是亟待解决的问题。将不可再生能源煤炭向多元化学品转化,降低对石油、天然气的消耗和对外依赖,一直是我国煤炭资源利用研究的重点方向。将煤经高温气化为CO和H2后,利用CO和H2合成气合成的草酸二甲酯(DMO)为原料,经催化加氢反应向多种含氧化学品转化是一条已被证实的可行技术路线。随着DMO经过间接加氢反应和连续加氢反应向乙醇酸甲酯(MG)、乙二醇(EG)、乙醇、碳酸二甲酯(DMC)和草酰胺等多种高值化学品转化技术的逐步发展,使我国丰富的煤炭资源得以高效利用,促进了我国能源结构的平衡。围绕DMO向下游产品转化展开详细论述和讨论。根据近年来学者对DMO的研究,DMO初步加氢可得到MG,MG二次加氢可得到EG,EG脱水得到乙醇、C3~C4醇,及DMO氨化制备“新型氮肥”———草酰胺等。重点归纳了各下游产品转化所使用催化剂的研究进展、不同催化剂的催化机理及活性物种的吸附-活化作用机制。详细梳理总结了当前通过引入其他助剂、调控表面酸碱度和引入第二第三金属等提高催化剂性能的方法。针对目前负载型铜基催化剂、铁基催化剂和银基催化剂等在DMO加氢过程中表现出的高选择性和局限性展开了细致的讨论。明确指出了随着产能的不断扩大,铜基催化剂所显现的高温易板结、中毒失活问题,铁基催化剂存在的中间产物加氢能力差及银基催化剂C—O键活化过程作用弱等问题,并进一步对催化剂失活原因和解决方法进行了细致的讨论和分析。详细指出了当前DMO加氢工艺路线存在的问题和挑战,给出了DMO加氢催化剂的未来研究方向和发展趋势。

China′s energy resource structure can be characterized as coal-rich but oil-lean and gas-lean, resulting in a high dependenceon coal resources. Therefore, how to give full play to the advantages of China′s large coal reserves and realize the cleaner, low-carbon,and diversified utilization of coal resources is an urgent problem to be solved. Converting non-renewable coal to diversified chemicals andreducing the consumption and external dependence on the use of oil and natural gas has been the key direction of China′s coal resourceutilization research. After the gasification of coal into CO and H2 at high temperatures, the conversion of dimethyl oxalate (DMO) synthesized from CO and H2 synthesis gas into a variety of oxygen-containing chemicals by catalytic hydrogenation reaction is a proven feasibletechnical route. With the gradual development of the technology for the conversion of DMO to a variety of high-value chemicals, suchas methyl glycolate (MG), ethylene glycol (EG), ethanol, dimethyl carbonate (DMC), and oxalamide, through indirect and continuoushydrogenation reactions, it has enabled China′s abundant coal resources to be utilized more efficiently and promoted the balance of China′senergy structure. This work centered on the conversion of DMO to downstream products in detail and discussion. According to the researchon DMO in recent years, the preliminary hydrogenation of DMO can obtain MG, the secondary hydrogenation of MG can obtain EG, thedehydration of EG can obtain ethanol, C3-C4 alcohol, and the ammoniation of DMO can prepare oxalamide, which is a " new type of nitrogen fertilizer" . The research progress of catalysts used in the conversion of downstream products, the catalytic mechanism of different catalysts, and the adsorption-activation mechanism of active species were summarized. The current methods to improve catalyst performanceby introducing other additives, regulating surface acidity and alkalinity, and introducing the second and third metals were summarized indetail. The high selectivity and limitations of the current loaded copper-based catalysts, iron-based catalysts, and silver-based catalystsin the DMO hydrogenation process were discussed in detail. The problems of high-temperature sliding and toxic deactivation of copperbased catalysts, poor intermediate product hydrogenation of iron - based catalysts, and weak C - O bond activation process of silver based catalysts with the continuous expansion of production capacity were pointed out, and the reasons for the deactivation of the catalystsand the solutions were further discussed and analyzed in detail. The problems and challenges of the current DMO hydrogenation processroute are pointed out in detail, and the future research direction and development trend of DMO hydrogenation catalysts were given.

0 引言

1 煤气化合成草酸酯

2 乙醇酸甲酯（MG）

   2.1 均相催化剂

   2.2 非均相催化剂

3 乙二醇（EG）

   3.1 煤制乙二醇

   3.2 不同载体影响

   3.3 不同助剂影响

   3.4 酸碱性影响

   3.5 活性机理研究

4 乙醇

   4.1 铜基催化剂

   4.2 非铜基催化剂

5 碳酸二甲酯

6 草酰胺

7 结语与展望