cuhmor催化二甲醚羰基化反应活性位的研究及调控word格式论文.docxVIP

摘要乙醇作为重要的基础化工原料和石油替代能源，具有广阔的发展前景和巨大 的市场潜力。基于我国“贫油、多煤、少气”的能源结构，以合成气为原料经二 甲醚（DME）羰基化制醋酸甲酯（MA）、醋酸甲酯加氢制乙醇的新型工艺是一 条非常有前途的工艺路线。氢型丝光沸石（H-MOR）分子筛由于其孔道限域效 应在 DME 羰基化反应表现出优异的选择性，而铜改性可以显著提高催化剂的活 性。本论文开展了 Cu/H-MOR 催化二甲醚羰基化反应活性位的作用机制及调控 研究。采用铜氨液体离子交换法及 CuCl 固体离子交换法分别制备了不同负载量的 Cu/H-M(x)及 SSIE Cu/H-M(x)催化剂。相比于 H-MOR，还原后的 Cu/H-M(x)样品 的催化活性明显提高，而 SSIE Cu/H-M(x)催化剂的活性则随铜负载量的增加而下 降。通过对还原前后及反应后 Cu/H-M(x)样品的酸量、种类和分布以及铜物种的 存在形式、位置等进行表征，明确了铜物种在制备、还原及反应过程中的变化历 程。通过建立 Cu/H-M(x)及 SSIE Cu/H-M(x)催化剂不同价态铜物种的量与 DME 羰基化反应活性的量化关系，明确了羰基化反应的活性铜物种为 Cu0，揭示了 Cu0 与 Br?nsted 酸的协同催化作用。另一方面，分子筛骨架破坏和 Cu0 物种的团 聚及向表面迁移均会导致反应活性的下降。为提高活性金属的利用效率，在较低的铜负载量下，通过调变还原温度及制 备方法获得了高分散度的 Cu0 活性物种，进而提高了 DME 羰基化反应的活性。 研究表明，适当提高还原温度和蒸氨过程均有利于增加高分散 Cu0 物种的比例。 相比铜氨液体离子交换法，蒸氨法制备的 Cu/H-MOR 催化剂其 DME 转化率可提 高近 30%。关键词：二甲醚，羰基化，Cu/H-MOR，醋酸甲酯，活性铜物种，Br?nsted 酸 位ABSTRACTAs an important chemical raw material and ideal alternative energy source of traditional fuels, ethanol has an expansive development potential and promising application foreground. Based on the energy structure of China, a novel syngas-to-ethanol route, including carbonylation of dimethyl ether (DME) to methyl acetate (MA) and hydrogenation of MA, is developed and has attracted much attention. It has been shown that H-MOR emerges enzyme-like specific selectivity for DME carbonylation reaction because of the spatial confinement effect of 8-member ring channels. Modification of H-MOR catalyst by Cu dopant leads to an obvious enhancement on the catalytic performance. This work focuses on identification of the copper active species in Cu/H-MOR and elucidation of their evolution during the preparation and reaction. Besides, it offers methods to modify Cu/H-MOR catalystswith more and better-dispered Cu0 species in order to improve catalytic activity.Ion-exchange with copper ammonia solution and solid state ion-exchange with CuCl methods were applied to synthesize Cu/H-MOR samples with different Cu loading, labeled as Cu/H-M(x) and SSIE Cu/H-M(x) respectively. Compared with H-MO