The ITQ-37 mesoporous chiral zeolite

Abstract

The synthesis of crystalline molecular sieves with pore dimensions that fill the gap between microporous and mesoporous materials is a matter of fundamental and industrial interest. The preparation of zeolitic materials with extralarge pores and chiral frameworks would permit many new applications. Two important steps in this direction include the synthesis of ITQ-33, a stable zeolite with 18 x 10 x 10 ring windows, and the synthesis of SU-32, which has an intrinsically chiral zeolite structure and where each crystal exhibits only one handedness. Here we present a germanosilicate zeolite (ITQ-37) with extralarge 30-ring windows. Its structure was determined by combining selected area electron diffraction (SAED) and powder X-ray diffraction (PXRD) in a charge-flipping algorithm. The framework follows the SrSi(2) (srs) minimal net and forms two unique cavities, each of which is connected to three other cavities to form a gyroidal channel system. These cavities comprise the enantiomorphous srs net of the framework. ITQ-37 is the first chiral zeolite with one single gyroidal channel. It has the lowest framework density (10.3 T atoms per 1,000 A(3)) of all existing 4-coordinated crystalline oxide frameworks, and the pore volume of the corresponding silica polymorph would be 0.38 cm(3) g(-1).

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Role of boron-containing ionic liquid in the synthesis of manganese borophosphate with extra-large 16-ring pore openings

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A New Microporous Zeolitic Silicoborate (ITQ-52) with Interconnected Small and Medium Pores

“…Zeolites have been applied for gas adsorption, separation, catalysis, encapsulation or controlled release of molecules, among others, some of them are of industrial application. [1][2][3][4][5][6][7][8][9] There is no doubt that this is the driving force for synthesizing new zeolite structures.Most of the zeolites described in the literature have been obtained by employing tetraalkylammonium cations as organic structure directing agents (OSDAs). 10-13 Recently, we have reported a number of new zeolites synthesized by using tetraalkylphosphonium cations 14 15 and ITQ-49 17 ) or phosphazenes (ITQ-47 18 ) as OSDAs.…”

“…Zeolites have been applied for gas adsorption, separation, catalysis, encapsulation or controlled release of molecules, among others, some of them are of industrial application. [1][2][3][4][5][6][7][8][9] There is no doubt that this is the driving force for synthesizing new zeolite structures.…”