Effect of selective 4-membered ring dealumination on mordenite-catalyzed dimethyl ether carbonylation
Effect of selective 4-membered ring dealumination on mordenite-catalyzed dimethyl ether carbonylation
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DOI：
10.1016/j.jcat.2017.03.010
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发表时间：
2017-05-01
影响因子：
7.3
通讯作者：
Semagina, Natalia
中科院分区：
文献类型：
--
作者：
Reule, Allen A. C.;Sawada, James A.;Semagina, Natalia
研究了一系列 Si/Al 比为 6.5 至 15.4 的脱铝丝光沸石的二甲醚羰基化反应生成乙酸甲酯的情况。通过用硝酸浸出实现脱铝。通过结合 DRIFTS、探针分子的 TPD、Al-27 MAS NMR、表面积、孔分布和 XRD 分析，建议选择性耦合去除分别位于 8 元和 12 元通道中 4 元环中的 T3 和 T4 Al 位点。当按 8 元环中的每个残留 T3 位点计算时，发现乙酸甲酯的峰值生产率是相等的，这提供了反应位点特异性的实验证据。虽然由于活性和选择性的 T3 位点去除，脱铝导致产物峰值速率降低，但它使催化剂寿命加倍，并且失活时的选择性从 50% 提高到 80%。该研究解耦了 4 元（T3 和 T4）和 5 元（T1 和 T2）酸位对产物形成和催化剂失活的影响。 (C) 2017 Elsevier Inc. 保留所有权利。
Dimethyl ether carbonylation to methyl acetate was studied on a series of dealuminated mordenites with Si/Al ratios of 6.5 through 15.4. Dealumination was achieved via leaching with nitric acid. Selective coupled removal of T3 and T4 Al sites located in 4-membered rings in 8- and 12-membered channels, respectively, was suggested by a combination of DRIFTS, TPD of probe molecules, Al-27 MAS NMR, surface area, pore distribution, and XRD analyses. The methyl acetate peak productivity was found to be equal when calculated per residual T3 sites in 8-membered rings, providing experimental evidence of the reaction site specificity. While dealumination led to the decrease in product peak rate because of active and selective T3 site removal, it doubled the catalyst lifetime and increased selectivity upon deactivation from 50% to 80%. The study decoupled the contribution of 4-membered (T3 and T4) and 5-membered (T1 and T2) acid sites to the products' formation and catalyst deactivation. (C) 2017 Elsevier Inc. All rights reserved.