Synthesis, Characterizations And Catalytic Properties Of MWW And IWR-type Metallosilicates

This dissertation focuses on the synthesis, characterizations and catalytic properties of MWW-type metallosilicates and ECNU-3 with the IWR framework. This dissertation is composed of four parts.In the first part, Ti-MWW has been hydrothermally synthesized for the first time in absence of crystallization-supporting agent such as boron acid by means of cooperative templating effects of N,N,N-trimethyl-1-adamantammonium hydroxide (l-TMAda⁺OH^-) and hexamethyleneimine (HMI) as second organic additives and potassium as a mineralization agent. Its physicochemical properties have been compared with that of hydrothermally synthesized (HTS) Ti,B-MWW, dry-gel conversion (DGC) synthesized Ti-MWW and postsynthesis synthesized (PS) Ti-MWW. As-synthesized Ti-MWW lamellar precursors contained both tetrahedral and octahedral species but the latter was small and selectively removed by acid treatment. Ti-MWW catalysts showed higher intrinsic activity than Ti,B-MWW and Ti-MWW-DGC, but slightly lower activity than Ti-MWW-PS in the epoxidation of 1-hexene with hydrogen peroxide.In the second part, Zr-MWW and Sn-MWW were also synthesized by means of cooperative templating effects of 1-TMAda⁺OH^- and HMI. Because of an in crease in bond distance of Zr-O (0.222 nm) > Sn-O (0.207 nm) > Ti-O (0. 179 nm ) > Si-O (0.160 nm), a decrease in crystallinity and a partial collapse of structure were caused by incorporation of Zr and Sn. We have successfully prepared Zr-MWW and Sn-MWW samples (low as Si/T=100) without loss of textural properties.In the third part, we have found that a commercially available linear quaternary ammonium, octyltrimethylammonium (OCTMAOH), was capable of directing the formation of MWW borosilicate in the absence of alkali cations. Furthermore, Ti-MWW was synthesized successfully using this SDA from the gel containing greatly reduced boric acid in comparison to the synthesis with piperidine (PI) or HMI.In the fourth part, ECNU-3 type zeolites, with intersecting 10- and 12-membered ring pores have been synthesized in the system GeO₂-SiO₂/SDA with two template molecules: benzyltrimethylammonium (TMBA) and dimethylhexamethyl eneimine (DMHMI). AST and BEC type zeolites have also been obtained in the presence of F'. The catalytic activity of Ti containing ECNU-3 for the epoxidation of1-hexene and cyclohexene was investigated.