Standardization of catalyst preparation using reference catalyst: ion exchange of mordenite type zeolite: 2. Origin of dealumination and recommended standard conditions
Standardization of catalyst preparation using reference catalyst: ion exchange of mordenite type zeolite: 2. Origin of dealumination and recommended standard conditions
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DOI：
10.1016/j.apcata.2005.01.026
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发表时间：
2005-04
影响因子：
5.5
通讯作者：
N. Katada;T. Takeguchi;Tatsuya Suzuki;Toshihisa Fukushima;Kinya Inagaki;S. Tokunaga;H. Shimada;Koich Sato;Y. Oumi;T. Sano;K. Segawa;K. Nakai;H. Shoji;Peng Wu;T. Tatsumi;T. Komatsu;T. Masuda;K. Domen;E. Yoda;J. Kondo;T. Okuhara;Takahide Kanai;M. Niwa;M. Ogura;M. Matsukata;E. Kikuchi;N. Okazaki;Motoi Takahashi;A. Tada;S. Tawada;Y. Kubota;Y. Sugi;Y. Higashio;M. Kamada;Yukiyo Kioka;Kohei Yamamoto;T. Shouji;S. Satokawa;Y. Arima;Y. Okamoto;H. Matsumoto
中科院分区：
文献类型：
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作者：
N. Katada;T. Takeguchi;Tatsuya Suzuki;Toshihisa Fukushima;Kinya Inagaki;S. Tokunaga;H. Shimada;Koich Sato;Y. Oumi;T. Sano;K. Segawa;K. Nakai;H. Shoji;Peng Wu;T. Tatsumi;T. Komatsu;T. Masuda;K. Domen;E. Yoda;J. Kondo;T. Okuhara;Takahide Kanai;M. Niwa;M. Ogura;M. Matsukata;E. Kikuchi;N. Okazaki;Motoi Takahashi;A. Tada;S. Tawada;Y. Kubota;Y. Sugi;Y. Higashio;M. Kamada;Yukiyo Kioka;Kohei Yamamoto;T. Shouji;S. Satokawa;Y. Arima;Y. Okamoto;H. Matsumoto
组织了一项联合研究，以建立一套将沸石从钠离子交换为质子形式的标准条件。 Si/Al2=ca的钠型丝光沸石。将15离子交换成NH4形式，然后根据各种配方进行煅烧。然后应用各种先进的表征技术（ICP、TG、XPS、SEM、XRD、N2吸附、29Si和27Al NMR、苯扩散、OH和吸附的吡啶和CO的IR、氨TPD），并进行了一些测试反应（异丙苯裂解、联苯异丙化、丙烯齐聚以及乙醛和氨缩合成甲基吡啶的chichibabin）。离子交换（钠的去除）按预期进行，但由此制备的质子形式样品的物理化学和催化性质观察到显着差异。离子交换的异常高温 (383K) 导致结构降解，而大多数在 333-353K 温度下交换的样品保持了结晶度和孔体积。 NH4Cl 的使用稍微改变了晶体形态。大多数样品在 773K 以上煅烧后形成了骨架外的铝物质。相比之下，673K 下的煅烧保持了铝的骨架。因此，认为脱铝是在从铵型沸石中完全除去氨之后进行的。然而，质子型沸石在干燥条件下是稳定的，因此推测脱铝是由于质子型沸石与潮湿的大气接触而引起的。总酸度和布朗斯台德酸度随着脱铝而降低，而路易斯酸度则增加。另一方面，铵型沸石的快速加热导致微孔变窄。这些结构变化严重影响了各种反应的催化活性。
A joint study was organized to establish a standard set of conditions for the ion exchange of zeolite from sodium into proton-form. The sodium-form mordenite with Si/Al2=ca. 15 was ion exchanged into an NH4-form, followed by calcination according to various recipes. Then various advanced techniques for characterization (ICP, TG, XPS, SEM, XRD, N2adsorption,29Si and27Al NMR, benzene diffusion, IR of OH and adsorbed pyridine and CO, ammonia TPD) were applied, and some test reactions (cracking of cumene, isopropylation of biphenyl, oligomerization of propene and chichibabin condensation of acetaldehyde and ammonia into picoline) were conducted. The ion exchange (removal of sodium) proceeded as expected, but remarkable differences were observed in physicochemical and catalytic properties of the thus-prepared proton-form samples. Exceptionally high temperature (383K) for the ion exchange resulted in the structural degradation, while most samples exchanged at 333–353K maintained the crystallinity and pore volume. The use of NH4Cl slightly changed the crystal morphology. Extra-framework aluminum species was formed on most samples after calcination above 773K. In contrast, calcination at 673K maintained the framework aluminum. Therefore, the dealumination is considered to proceed after complete removal of ammonia from the ammonium-form zeolite. However, the proton-form zeolite was stable under dry conditions, so it is speculated that the dealumination was induced by the contact of the proton-form zeolite to atmosphere with humidity. The total and Brønsted acidity decreased with the dealumination, while Lewis acidity increased. On the other hand, rapid heating of the ammonium type zeolite caused narrowing of the micropores. These structural changes seriously affected the catalytic activities for various reactions.