Abstract:

The carbonylation of dimethyl ether (DME) to produce methyl acetate (MA) and the hydrogenation of MA to ethanol is a novel, green and economical ethanol synthesis route. The formation of the catalyst is of great significance to the industrialization of this process. In this paper, pseudo-boehmite and silica sol are used as binders, and mordenite molecular sieve (MOR) is extruded to prepare a series of molded MOR catalysts with different binder types and contents. By using strength evaluation and Weibull distribution analysis, we investigated the mechanical stability and reliability of the extruded MOR. Afterwards, XRD, N₂-physisorption, NH₃-TPD and IR spectra of pyridine adsorption were employed to explore the influence of binder on textural properties, acidity and catalytic performance. The results showed that the crystal structure of MOR was maintained after addition of binder. When the pseudo-boehmite was used as a binder, the catalyst showed the best mechanical property and catalytic activity. By establishing the quantitative relationships among the yield, TOF and structure parameter, it is found that the space time yield of MA was linearly related to the specific surface area of micropores. Meanwhile, the almost constant TOF indicated that the binders did not affect the catalytic capacity of each activesites in MOR for carbonylation of dimethyl ether.

Key words: zeolite, syngas, catalyst, fixed-bed, extrusion, binder

摘要：

二甲醚（DME）羰基化制乙酸甲酯（MA），MA加氢合成乙醇工艺是一种新颖、绿色且经济的乙醇合成路线，催化剂成型对实现该工艺工业化具有重要意义。本论文选用拟薄水铝石及硅溶胶为黏结剂，对丝光沸石分子筛（MOR）进行挤条成型，制备了一系列不同黏结剂种类与含量的成型MOR催化剂。通过强度测试以及Weibull函数统计分析，探究了黏结剂对成型MOR的强度以及强度可靠性的影响；X射线衍射、N₂物理吸附、NH₃程序升温脱附、吡啶吸附原位红外等表征结合活性评价，探究了黏结剂对MOR的物理结构、酸性以及催化性能的作用。结果表明：黏结剂的引入不会影响MOR的晶体结构，且以拟薄水铝石为黏结剂时，催化剂力学性能及DME羰基化催化性能最佳。通过建立MA时空收率、TOF与微孔比表面积之间的定量关系，确定黏结剂不影响MOR内单位活性位点催化能力，产物时空收率与催化剂微孔比表面积呈线性正相关。

关键词: 分子筛, 合成气, 催化剂, 固定床, 挤条成型, 黏结剂