Transformation of kanemite into silicalite 1: parameters affecting the cation exchange reaction

Abstract

The optimum crystallization conditions for the transformation of kanemite into silicalite 1 have been determined by X-ray powder diffraction, thermal analysis and 29 Si NMR spectroscopy. The synthesis of silicalite 1 was favored by the use of a TPAOH template, in preference to a TPABr template, highly basic conditions during stirring of the suspension at 70 ³C and the adjustment of the pH to 8.5 after stirring. The more the layered structure of kanemite disintegrated after the cation exchange reaction, the higher the amount of incorporated template and the higher the crystallinity of silicalite 1 after the solid-state transformation. The dissolution process that occurs during the cation exchange reaction with short-chain alkylammonium cations was different from that which occurs in the case of long-chain alkylammonium cations which are used for the synthesis of mesoporous materials.

Synthesis and crystal structure of layered silicate PLS-3 and PLS-4 as a topotactic zeolite precursor

“…14,15 Furthermore, polycrystalline silicates such as FLS, silicalite-1, silicalite-2 and zeolite beta can be obtained by a solidstate reaction using magadiite or kanemite. [16][17][18][19][20][21] The solid-state reaction has the advantage of a very short reaction time, i.e. less than 24 h, with low consumption of water, similar to a dry-gel conversion method.…”

Solid–solid transformation route to nanocrystalline sodalite from Al-PILC at room temperature

“…Recently, a great deal of effort has been directed at the exploitation of zeolite synthesis by solidsolid transformation, since the hydrothermal method not only requires excess water for the reaction, but it also results in production of an alkaline waste solution [6,7]. These approaches exhibited much higher product yield, lower elemental losses, and shorter nucleation and crystal growth, compared to the hydrothermal reaction method.…”

“…These approaches exhibited much higher product yield, lower elemental losses, and shorter nucleation and crystal growth, compared to the hydrothermal reaction method. In addition, the solid -solid transformation also present the advantage of obtaining nanocrystalline particles which exhibit fascinating potentials because a discrete small size allows faster diffusion of reactants into inner active surface as well as the fabrication of defect-minimized film [7].…”

Pseudo-micropores formed by one-dimensional framework with hydrogen bonding in CsHSi2O5 observed by synchrotron powder diffraction and solid-state MAS NMR

“…Linear or layered silicates are the fundamental structures for various crystalline silicates and are potential precursors and building blocks for useful industrial crystalline silicates. Solid-state transformations of layered silicates to microporous materials have been investigated [2][3][4][5][6][7] and found to form porous crystals much faster than the corresponding conventional hydrothermal syntheses. Designing linear silicate chains is, therefore, very attractive since linear frameworks are easily converted into two-or three-dimensional networks by the dehydration condensation of terminal silanols.…”