MWW-type Tinsilicate: Direct Synthesis, Structural Transfer To MCM-56 Analogue And Catalytic Properties In Baeyer-Villiger Oxidations

Systematic research has been carried out in developing a novel solid acid catalyst on the basis of MWW-type zeolite.The first part of this dissertation describes the procedures of synthesizing Sn-MWW zeolite, using piperidine (PI) as structure-directing agent (SDA), boric acid as a crystallization-supporting agent and Tin tetrachloride as a Tin source. We found that boric acid and sodium hydroxide play the key role in the whole crystallization, without them we only obtained amorphous products, which was the same as the synthesis of Zr-MWW. When using colloidal silica (30 wt %) as silica source and obeying the synthesis recipe of NaOH/Si=0.18-0.3, Si/B=2.5-4, H2O/Si=19, PI/Si=1.4, products with full crystallization were gained even with Si/Sn=40.In the second part of this thesis, we transformed Sn-MWW into Sn-MCM-56 by post-treatment method. When lamellar precursors were treated in 2M HNO3 at 373K, the 001 and 002 diffractions disappeared, leading to three dimensional structure zeolite. However, when lamellar precursors were treated in 2M HNO3 at room temperature, we would acquire MCM-56 analogues which possessed a larger external surface and an opener reaction space, therefore alleviated effectively the steric restriction and diffusion limitation to bulky molecules that the microporous catalysts usually encountered.The last part of the thesis describes their catalytic performance in Baeyer-Villiger oxidation. Sn-MCM-56 was better than Sn-MWW not only in reaction rate but also final conversion in terms of similar tin content. In addition, when using bulky oxidant TBHP, the performance of Sn-MCM-56 was even better than Sn-beta.