Delamination of Ti-MWW and high efficiency in epoxidation of alkenes with various molecular sizes
Delamination of Ti-MWW and high efficiency in epoxidation of alkenes with various molecular sizes
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DOI：
10.1021/jp037459a
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发表时间：
2004-12-16
影响因子：
3.3
通讯作者：
Tatsumi, T
中科院分区：
文献类型：
--
作者：
Wu, P;Nuntasri, D;Tatsumi, T
采用环胺辅助合成高波化MWW沸石后合成Ti-MWW的层状前驱体，对其进行分层制备了一种新型钛硅酸盐，命名为Del-Ti-MWW。在层状结构膨胀过程中，支持表面活性剂的有机碱用量应严格控制，以保证层状结构有效分层而不致坍塌。超声治疗被证明可以更彻底地剥离肿胀的材料。Del-Ti-MWW材料具有较大的表面积，有效地减轻了传统微孔钛硅酸盐对大体积分子的空间限制。dl -Ti-MWW保持了MWW沸石的基本结构和骨架位置的四面体Ti物质，在过氧化氢对大范围体积烯烃的环氧化反应中优于TS-1、Ti- beta、三维Ti-MWW甚至介孔Ti- mcm -41。
A new titanosilicate, named Del-Ti-MWW, has been prepared by delaminating the lamellar precursor of Ti-MWW, which is postsynthesized from highly deboronated MWW zeolite with the assistance of cyclic amine. The amount of organic base used for supporting surfactant in swelling the layered structure should be controlled carefully to delaminate efficiently without the collapse of the structure. Ultrasound treatment is demonstrated to delaminate the swollen material more completely. Del-Ti-MWW materials have a large surface area, which mitigates effectively the steric restrictions imposed by conventional microporous titanosilicates to bulky molecules. Del-Ti-MWW, maintaining the fundamental structure of MWW zeolite and tetrahedral Ti species in the framework position, proves to be superior to TS-1, Ti-Beta, three-dimensional Ti-MWW and even mesoporous Ti-MCM-41 in the epoxidation of a wide range of bulky alkenes with hydrogen peroxide.