Influence of the Lewis acidity of indium-modified beta zeolite in the m-xylene transformation
Influence of the Lewis acidity of indium-modified beta zeolite in the m-xylene transformation
复制标题
铟改性β沸石路易斯酸度对间二甲苯转化的影响
DOI：
10.1016/s0926-860x(00)00833-4
复制
发表时间：
2001
影响因子：
5.5
通讯作者：
C. Minchev
中科院分区：
文献类型：
--
作者：
V. Mavrodinova;M. Popova;Y. Neinska;C. Minchev
采用还原性固态离子交换法（RSSIE），在NH 4-β分子筛上引入不同数量的In+，研究了其在间二甲苯转化反应中的催化性能。它已被证明，在阳离子被认为是具有刘易斯酸性的配位不饱和物种显着改变催化剂的稳定性和反应的选择性时，在惰性气氛中进行。In-改性β沸石加速了沸石的脱水和结焦副反应，推测其机理是夺取氢离子和加快苄型阳离子的生成。在H2的存在下，这些反应被强烈抑制，以牺牲异构化的主要反应为代价。在完全In交换的β沸石上，提出了异构化的部分双分子机理。
The catalytic performance of NH4-beta zeolite containing different amounts of indium, introduced as In+cations by the method of reductive solid-state ion exchange (RSSIE), has been studied in the m-xylene conversion. It has been shown that In cations regarded as coordinatively unsaturated species possessing Lewis acidity substantially change the catalyst stability and the selectivity of the reaction when performed in an inert atmosphere. An acceleration of the side reactions of disproportionation and coking has been observed on the In-modifications of zeolite beta and a mechanism of hydride ion abstraction and faster benzylic cation formation on them have been supposed. In presence of H2these reactions are strongly suppressed at the expense of the main reaction of isomerisation. On the completely In-exchanged beta zeolite a partial bimolecular mechanism of isomerisation is suggested.