NANOMETER-SIZE ZEOLITIC PARTICLES AND METHOD FOR THE PRODUCTION THEREOF

Abstract

A particulate material and a process for the production thereof are provided, which particulate material comprises zeolitic particles having a crystalline structure, which contain as the main component a zeolite material having a zeolitic framework structure formed from Si, O and optionally Al, and/or a zeolite-like material having a zeolitic framework structure which is formed not only from Si, O and optionally Al, wherein the zeolitic particles are in the form of essentially spherical particles with nanometer dimensions.

Claims

1. A particulate material which comprises zeolitic particles having a crystalline structure, which contain as the main component a zeolite material having a zeolitic framework structure formed from Si, O and optionally Al, and/or a zeolite-like material having a zeolitic framework structure which is formed not only from Si, O and optionally Al, characterized in that the zeolitic particles are in the form of essentially spherical particles with nanometer dimensions.

2. The particulate material as claimed in claim 1, characterized in that it comprises zeolitic particles which contain one or more metal-containing components that are not involved in the structure of the zeolitic framework material.

3. The particulate material as claimed in claim 1, characterized in that at least 90% of all the zeolitic particles, expressed in terms of the particle number, have a particle size of from 50 to 200 nm.

4. The particulate material as claimed in claim 1, characterized in that the zeolitic framework structure is formed from tetrahedral SiO.sub.2 units, wherein up to 30% of all the silicon atoms in the framework structure may be replaced by one or more other network-forming elements selected from elements of main groups 3, 4 and 5 of the periodic table.

5. The particulate material as claimed in claim 1, characterized in that the zeolitic framework structure is a high-silica zeolite structure.

6. The particulate material as claimed in claim 1, characterized in that less than 10% of the zeolitic particles, expressed in terms of the particle number, are grown together to form aggregates.

7. A process for producing a particulate material which comprises zeolitic particles having a crystalline structure, which contain as the main component a zeolite material having a zeolitic framework structure formed from Si, O and optionally Al, and/or a zeolite-like material having a zeolitic framework structure which is formed not only from Si, O and optionally Al, wherein the zeolitic particles are in the form of particles with nanometer dimensions, characterized in that the process comprises the following steps: a) providing a starting material comprising porous starting particles, which are formed from at least one oxide that can form a zeolite material having a zeolitic framework structure or a zeolite-like material having a zeolitic framework structure; b) introducing a solution or dispersion of an organic compound, which can act as a template for the synthesis of a zeolitic framework structure, into the pores of the porous starting particles, and subsequently fully or partially removing the solvent of the solution or dispersion, so that the organic compound remains in the pores of the porous starting particles; c) converting the starting material obtained in step b), which contains the porous starting particles with the organic compound in the pores, by heating the starting material in contact with steam so that the zeolitic particles are formed.

8. The process as claimed in claim 7, wherein the particulate material produced by the method is the particulate material as claimed in one of claims 1 to 7, and wherein the zeolitic particles are in the form of essentially spherical particles with nanometer dimensions.

9. The process as claimed in claim 7, wherein the pore volume of the pores with a diameter of 1 nm or more in the porous starting particles of the starting material lies in the range of from 0.2 to 2.0 ml/g, expressed in terms of the weight of the porous starting particles.

10. The process as claimed in claim 7, wherein the introduction of the solution or dispersion in step b) is carried out such that the solution or dispersion penetrates into all pores that are open toward the particle surface, with a diameter of 1 nm or more, of the porous starting particles of the starting material.

11. The process as claimed in claim 7, wherein the fill factor of the pores with a diameter of 1 nm or more of the porous starting particles obtained in step b) with the organic compound, defined as the ratio of the volume of the organic compound contained in the pores and the pore volume of the mesopores of the particles, is from 50 to 100%.

12. The process as claimed in claim 7, wherein a metal compound is additionally introduced into the pores of the porous starting particles of the starting material in step b).

13. The process as claimed in claim 7, wherein the organic compound is a tetraorganoammonium cation or a tetraorganophosphonium cation.

14. The process as claimed in claim 7, characterized in that at least 90% of the porous starting particles of the starting material, expressed in terms of the particle number, have a particle size of between 100 nm and 1000 nm.

15. The use of the particulate material as claimed in claims 1 as a catalyst in a heterogeneously catalyzed method, in a sorption process, as a carrier for the immobilization of guest molecules, as a sensor, or as a sensing component in sensors.

Description

DESCRIPTION OF THE FIGURES

[0182] FIG. 1 shows by way of example a schematic representation of the main steps in the production of zeolitic nanoparticles of the MFI type.

[0183] FIG. 2 shows by way of example a schematic representation of the various steps and the experimental setup in the production of zeolitic nanoparticles of the MFI type.

[0184] FIG. 3 shows a scanning electron microscope (SEM) image of the nanozeolites of the MFI type produced according to Example 1 (comparative example).

[0185] FIG. 4 shows an X-ray diffractogram of the calcined mesoporous silicon dioxide particles of Example 2.

[0186] FIG. 5 shows a scanning electron microscope image of the calcined mesoporous silicon dioxide particles of Example 2.

[0187] FIG. 6 shows the nitrogen sorption isotherm (a) and DFT pore size distribution (b) of the calcined mesoporous silicon dioxide particles of Example 2.

[0188] FIG. 7 shows a scanning electron microscope image of the calcined mesoporous silicon dioxide particles of Example 3.

[0189] FIG. 8 shows an X-ray diffractogram of the calcined mesoporous silicon dioxide particles of Example 3.

[0190] FIG. 9 shows a scanning electron microscope image (a) and an X-ray diffractogram (b) of the zeolite nanoparticles of the MFI type without aluminum according to Example 4 (according to the invention). As a comparison, an SEM image (FIG. 5) of a nanozeolite of the MFI type produced according to Example 1 (comparative example) is shown.

[0191] FIG. 10 shows the nitrogen sorption isotherm of the calcined mesoporous silicon dioxide particles and the zeolite nanoparticles of the MFI type without aluminum according to Example 4.

[0192] FIG. 11 shows an X-ray diffractogram of the aluminum-containing zeolitic nanoparticles of the MFI type of Example 5.

[0193] FIG. 12 shows a scanning electron microscope image of the aluminum-containing mesoporous silicon dioxide particles of Example 3 (a) and of the zeolitic nanoparticles of the MFI type (b) of Example 5.

[0194] FIG. 13 shows an X-ray diffractogram of Nano-Pt/ZSM-5 of Example 6.

[0195] FIG. 14 shows a scanning electron microscope image of the aluminum-containing mesoporous silicon dioxide particles of Example 3 (a) and of the Nano-Pt/ZSM-5 particles (b) of Example 6.

[0196] FIG. 15 shows the particle size distribution of the starting particles produced in Example 2 (MSP) and of the nanoparticles obtained in Example 4 (with a conversion time in the autoclave of 6 and 12 h, respectively).