摘要 二甲醚（DME）羰基化制乙酸甲酯（MA）是合成气制燃料乙醇的重要环节。丝光沸石（MOR）是目前DME羰基化最具工业化前景的催化剂。但对于微孔分子筛来说，扩散性能往往是影响催化性能的重要因素。本工作对MOR分别采用不同浓度的乙酸溶液处理及正硅酸乙酯（TEOS）化学沉积，采用X射线荧光光谱（XRF）、X射线衍射（XRD）、核磁共振（27Al MAS NMR）、N2物理吸附、NH3程序升温脱附（NH3-TPD）和吡啶吸附红外光谱（Py-IR）等表征分析各催化剂，结合催化剂表征和扩散动力学实验探讨扩散性质对羰基化性能的影响。结果表明：采用乙酸后处理及正硅酸乙酯化学沉积基本不影响MOR分子筛的理化性质。随着乙酸处理浓度增加，DME初始转化率先增大后降低，MA的表观生成速率（TOFMA）对乙酸处理浓度单调递增；正硅酸乙酯沉积后样品的DME初始转化率与表观TOFMA均降低。利用零长柱法（ZLC）定量分析了DME在不同样品中的扩散性质。结果表明：经乙酸处理后，DME的扩散活化能降低；经TEOS处理后，DME扩散活化能增加，说明表观TOFMA的变化是由于扩散差异引起的。
Abstract：Carbonylation of dimethyl ether (DME) to methyl alcohol (MA) is an important step to produce ethanol from syngas. Mordenite (MOR) is the most promising industrial catalyst for DME carbonylation process. In microporous zeolites, diffusion property usually affects catalytic performance. In this study, we treated MOR by using acetic acid solution with different concentrations and tetraethyl orthosilicate (TEOS), respectively. The catalysts were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), nuclear magnetic resonance (7Al MAS NMR), N2 physical adsorption, N2 physical adsorption, NH3 temperature-programmed desorption (NH3-TPD) and pyridine Fourier infrared spectroscopy (Py-IR). The results indicated that the post-treatment by acetic acid solution or tetraethyl orthosilicate had limited effects on the physical structure and chemical properties of the MOR samples. With increasing acetic acid concentration, the initial conversion of DME (XDME) first increased and then decreased, and the apparent initial MA formation rate (TOFMA) increased monotonically. While both the XDME and the TOFMA decreased after TEOS deposition. The diffusion property of DME in different samples were quantitatively analyzed by Zero Length Column (ZLC) method. The results showed that the diffusion activation energy reduced after acetic acid treatment and increased after TEOS treatment, suggesting that the changes in apparent TOFMA was due to difference in diffusion property.
WANG Jianhao,XIA Yumeng,LI Ying et al. Effect of Post Treatment on the Structural and Diffusion Properties of Mordenite Catalyst in Dimethyl Ether Carbonylation[J]. Chemical Reaction Engineering and Technology, 2021, 37(6): 520-527.
