Lee Hyunjoo, Zones Stacey I, Davis Mark E
Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.
J Phys Chem B. 2005 Feb 17;109(6):2187-91. doi: 10.1021/jp048908p.
Zeolites and molecular sieves are synthesized using organic structure-directing agents (SDAs) that have the potential to be degraded into fragments within the pore space so that they can be readily extracted at mild conditions. The zeolites and molecular sieves, VPI-8, ZSM-12, and ZSM-5, are synthesized using the ketal-containing SDA, 8,8-dimethyl-1,4-dioxa-8-azoniaspiro[4,5]decane (SDA-1). As expected, solids with unidimensional pore systems (VPI-8, ZSM-12) are much more difficult to process by this methodology than solids containing multidimensional pore systems (ZSM-5). Pore-filling agents (PFAs) such as isobutylamine and cyclopentylamine are used together with the ketal-containing SDA-1 to prepare ZSM-5. Extraction of the PFA is shown to be feasible, and its removal provides space for components to enter the zeolite micropores where they react with and cleave SDA-1. Removal of the cleavage fragments from SDA-1 gives ZSM-5 that has the appropriate pore volume, framework aluminum (measured by 27Al NMR), and catalytic behavior. Reasons for desiring this new type of zeolite synthesis method are enumerated.
沸石和分子筛是使用有机结构导向剂（SDA）合成的，这些导向剂有可能在孔道内降解成碎片，从而可以在温和条件下轻松提取出来。VPI - 8、ZSM - 12和ZSM - 5等沸石和分子筛是使用含缩酮的SDA，即8,8 - 二甲基 - 1,4 - 二氧杂 - 8 - 氮杂螺[4,5]癸烷（SDA - 1）合成的。正如预期的那样，与含有多维孔道系统的固体（ZSM - 5）相比，具有一维孔道系统的固体（VPI - 8、ZSM - 12）用这种方法处理起来要困难得多。孔填充剂（PFA），如异丁胺和环戊胺，与含缩酮的SDA - 1一起用于制备ZSM - 5。结果表明，PFA的提取是可行的，其去除为组分进入沸石微孔提供了空间，在微孔中这些组分与SDA - 1反应并使其裂解。从SDA - 1中去除裂解片段后得到的ZSM - 5具有合适的孔体积、骨架铝（通过27Al NMR测量）和催化性能。文中列举了期望这种新型沸石合成方法的原因。
