Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022 Valencia, Spain.
Science. 2017 Mar 10;355(6329):1051-1054. doi: 10.1126/science.aal0121.
Unlike homogeneous catalysts that are often designed for particular reactions, zeolites are heterogeneous catalysts that are explored and optimized in a heuristic fashion. We present a methodology for synthesizing active and selective zeolites by using organic structure-directing agents that mimic the transition state (TS) of preestablished reactions to be catalyzed. In these zeolites, the pores and cavities could be generated approaching a molecular-recognition pattern. For disproportionation of toluene and isomerization of ethylbenzene into xylenes, the TSs are larger than the reaction products. Zeolite ITQ-27 showed high disproportionation activity, and ITQ-64 showed high selectivity for the desired para and ortho isomers. For the case of a product and TS of similar size, we synthesized a catalyst, MIT-1, for the isomerization of -dicyclopentane into adamantane.
与通常针对特定反应设计的均相催化剂不同，沸石是多相催化剂，以启发式方式进行探索和优化。我们提出了一种通过使用有机结构导向剂合成活性和选择性沸石的方法，这些结构导向剂模拟要催化的预先确定反应的过渡态（TS）。在这些沸石中，孔和腔可以通过接近分子识别模式来产生。对于甲苯的歧化和乙苯异构化为二甲苯，TS 大于反应产物。沸石 ITQ-27 表现出高的歧化活性，而 ITQ-64 对所需的对位和邻位异构体表现出高选择性。对于产物和 TS 大小相似的情况，我们合成了一种催化剂 MIT-1，用于 -二环戊烷异构化为金刚烷。
