Template-free clathrasils and clathrasil membranes
AssigneeBASF SE
InventorsHartwig Voβ, Jörg Therre, Hermann Gies, Bernd Marler
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Abstract
The present invention relates to template-free clathrasils whose framework comprises essentially SiO2, wherein the crystals of the clathrasils have the platelet-like morphology of a sheet silicate. The present invention further relates to a process for preparing these template-free clathrasils and also to their use as absorbent, as seed crystals for the synthesis of clathrasil membranes of the same zeolite type and in the form of dense layers which function as gas separation membranes having a molecular sieving action.
Claims16
A template-free clathrasil whose framework comprises essentially SiO2, wherein the crystals of the clathrasil have a platelet-like morphology of a sheet silicate, and wherein the clathrasil is template-free.
A process for preparing template-free clathrasils whose framework comprises essentially SiO2 from sheet silicates, which comprises the following steps:
- (i) replacement of the cations intercalated in the interlayers of the sheet silicates and, if present, at least part of the water of crystallization by at least one organic and polar, water-soluble compound,
- (ii) thermal topotactic condensation of the sheet silicates exchanged with at least one organic compound to form clathrasils.
A process for producing clathrasil membranes from clathrasil seed crystals which have been derived from a sheet silicate, which comprises the following steps:
- (i) replacement of the cations intercalated in the interlayers of the sheet silicate crystals and, if present, at least part of the water of crystallization by at least one organic and polar, water-soluble compound,
- (ii) deposition of the sheet silicate crystals exchanged with at least one organic compound on an inorganic porous support,
- (iii) thermal topotactic condensation of the sheet silicate crystals exchanged with at least one organic compound to form clathrasil seed crystals,
- (iv) hydrothermal synthesis of a clathrasil membrane.
A process for producing template-free clathrasil membranes from sheet silicate crystals, which comprises the following steps:
- (i) replacement of the cations intercalated in the interlayers of the sheet silicate crystals and, if present, at least part of the water of crystallization by at least one organic and polar, water-soluble compound,
- (ii) deposition of the sheet silicate crystals exchanged with at least one organic compound on an inorganic porous support until a layer of sheet silicate crystals which covers the support has been formed,
- (iii) thermal topotactic condensation of the sheet silicate crystals exchanged with at least one organic compound in the deposited layer to give a clathrasil membrane.
Dependencies are inferred from the claim text.