Novel Three Dimensional Cubic Fm3m Mesoporous Aluminosilicates with Tailored Cage Type Pore Structure and High Aluminum Content

Abstract

Novel three dimensional cubic Fm3m mesoporous aluminosilicates (AlKIT‐5) with very high structural order and unprecedented loadings of Al in the silica framework have been successfully prepared for the first time by using non ionic surfactant as a template in a highly acidic medium. The obtained materials have been unambiguously characterized in detail by several sophisticated techniques such as XRD, N2 adsorption, HRTEM, HRSEM, EDS, elemental mapping, 27Al MAS NMR, and NH3‐TPD. We also demonstrate that the nature, and the amount of Al incorporation in the silica framework can easily be controlled by simply varying the nH2O/nHCl and the nSi/nAl ratios, and the Al sources in the synthesis gel. Among the Al sources examined, the Al isopropoxide (AiPr) is superior over other Al sources. 27Al MAS NMR results reveal that the amount of tetrahedral Al in the framework can be controlled by simply adjusting the nSi/nAl ratio in the synthesis gel, which increases with increasing the Al incorporation. One of the interesting findings in the work is the increase of the specific surface area, specific pore volume and the pore diameter of AlKIT‐5 with increasing the Al incorporation in the silica framework (up to nSi/nAl ratio of 10) while retaining the well‐ordered three dimensional cage type porous structure, and the mechanism for the unusual behavior has been discussed in detail. Finally, the acidity and the catalytic activity in the acetylation of veratrole of the AlKIT‐5 catalysts have been studied and the results have been compared with the several zeolites catalysts. Among the catalysts examined, AlKIT‐5(10) is found to be superior over the zeolites catalysts such as mordenite, zeolite H‐Y, zeolite H‐β, and ZSM‐5.

Synthesis of Superacid‐Functionalized Mesoporous Nanocages with Tunable Pore Diameters and Their Application in the Synthesis of Coumarins

“…www.chemeurj.org showed higher catalytic activity for acetylation of veratrole and ring opening of epoxides than the zeolites and other metal-substituted mesoporous materials. [17,52] However, the catalytic activity of AlKIT-5 in the synthesis of coumarin derivatives is less than that of KIT-5A C H T U N G T R E N N U N G (100)-20TA. This is mainly due to the presence of a huge number of acidic sites on the surface of the KIT-5 support that come from the TFA molecules and are easily available to the reactant molecules.…”

“…Very recently, Vinu et al reported the preparation of aluminum-supported mesoporous KIT-5 material (AlKIT-5), which possesses a 3D mesostructure with Fm3m symmetry and excellent textural characteristics. [17] Although the material showed excellent performance in the acid-catalyzed reactions, the acidity of the material is much lower than zeolites and zeotype materials. By increasing the acidity of the KIT-5 materials, the possibility of using the material as a catalyst for various acid-catalyzed organic transformations could be extended.…”

Enzyme-Encapsulated Layer-by-Layer Assemblies: Current Status and Challenges Toward Ultimate Nanodevices

“…Mesoporous materials can be attractive materials for many kinds of applications [278][279][280], because these materials provide huge surface areas and pore volumes as well as well-defined pore geometries [281][282][283][284][285][286][287][288]. Research on mesoporous materials is currently extremely popular and detailed descriptions can be found in several reviews [289][290][291][292][293][294][295] and reports on advanced functions [296][297][298][299].…”

Selective Monoacylation of Ferrocene with Bulky Acylating Agents over Mesoporous Sieve AlKIT‐5

“…[4][5][6][7][8][9][10] With respect to that, mesoporous materials that possess three-dimensional cage-type pore structures such as SBA-1, SBA-16, and KIT-5 are nowadays considered more promising as they are more resistant to pore blocking, they allow for a faster diffusion of the reactants, and they provide more adsorption sites, which are more accessible through the three-dimensional porous structure. [11] Mesoporous molecular sieves have received considerable attention owing to their narrow pore-size distributions, high surface areas, and large pore volumes. [12][13][14][15][16] Among the materials mentioned above, KIT-5 is particularly interesting as it possesses a highly ordered three-dimensional mesoporous structure with cubic Fm3m close-packed symmetry, a large surface area, pores with tunable diameter, a large specific pore volume, and large cages.…”