Chemistry of inorganic compounds – Zeolite – Organic compound used to form zeolite
Reexamination Certificate
1999-09-22
2001-11-20
Sample, David R. (Department: 1755)
Chemistry of inorganic compounds
Zeolite
Organic compound used to form zeolite
C423S705000, C423S716000, C423S327100, C423S328200, C423S335000
Reexamination Certificate
active
06319486
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a mesoporous aluminosilicate or pure-silica molecular sieves, and in particular relates to a mesoporous aluminosilicate or pure-silica molecular sieves composed of hollow balls or hollow balls with pillars in them or solid spheres.
BACKGROUND OF THE INVENTION
Recently, the discovery of the new family of crystalline mesoporous materials M41S by researchers at Mobil Corp. (U.S. Pat. No. 5,108,725) has attracted great attention. These mesoporous molecular sieves with adjustable and uniformed pore sizes in the range of 1.5 to 10.0 nm can be applied in various fields. MCM-41, one member of this series, possessing a hexagonal arrangement of uniformly sized channel mesopores, has been the focus of the most recent applications in catalysts and absorbents for larger molecules.
Since the MCM-41 materials were synthesized from a complex mixture of surfactants and silicate, the behavior and the structure of the system might be variable. However, the previous literature reported that the morphology of MCM-41 material was limited in microparticles. This is caused by two reasons. One is that the MCM-41 structure was always prepared from acidifying highly condensed silicate form; it is too rigid to bend into other large-scaled morphologies. Second, there is no suitable micron-sized template existed in the synthetic composition to prepare the hierarchical structure. Therefore, there is an opportunity to tailor the morphology of MCM-41 products to a designed structure by using a soft or less condensed silicon source and a proper composition promoting the formation of micron-sized template.
Based on the theory of surfactant complex fluids, the morphology of aggregates formed by self-assembly of surfactants in solution and the evolution of morphology with additives, such as alcohol with medium chain length, is of current interest. Thus, we added a proper amount of alcohol into surfactant-silicate synthetic system to produce the mesoporous materials with special micron-sized morphologies.
SUMMARY OF THE INVENTION
The present invention provides a method for making mesoporous molecular sieves by adding the desired amount of alcohol.
Another object of the present invention is to provide a pure-silica molecular sieve having a hollow spherical morphology with a pillar inside and a method forming the same.
A further object of the present invention is to provide an aluminosilicate molecular sieve having a hollow spherical morphology and a method forming the same.
A still further object of the present invention is to provide a pure-silica molecular sieve having a solid spherical morphology and a method forming the same.
(1) Synthesis of a Pure-silica Molecular Sieve Having a Hollow Spherical Morphology with a Pillar Inside.
The alcohol was added to a clear aqueous solution of the surfactant silicate under stirring and a gel mixture was formed. After stirring for about 10-30 minutes at room temperature, a proper amount of sulfuric acid or other acids was gradually added into the gel mixture. The pH value of the final mixture was adjusted to about 11.5-9.0. The molar ratio of the resultant gel composition was about within 1 surfactant:(3.0-0.3) SiO
2
:(2.78-0.40)NaOH:(2.50-0.3) HA:(3.0-0.1) alcohol:(50-2000) H
2
O. Then, the mixture is loaded into an autoclave and statically heated at about (20-25° C.) for about 1-480 hours. The resulting solid products were recovered by filtration, washed with deionized water and dried in air at room temperature or 100° C. To remove the organic species in the pores of mesoporous silicate, the as-synthesized sample were calcined in air at 500-900° C. for about 6-12 hours.
(2) Synthesis of an aluminosilicate molecular sieve having a hollow spherical morphology.
The aluminosilicate was synthesized with the same process mentioned in (1) except that a suitable amount of sodium aluminate aqueous solution was added into the aqueous solution of surfactant-silicate. The silicate/aluminate molar ratio. is about 60-10.
(3) Synthesis of a pure-silica molecular sieve having a solid spherical morphology.
The silicate was synthesized with the same process mentioned in (1) except that a suitable amount of tetraethylorthosilicate (TEOS) was added into the aqueous solution of surfactant-silicate. The molar ratio of TEOS/surfactant is about 10-0.5.
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Yang et al., “Synthesis of Mesoporous Silica Species under Quiescent Aqueous Acidic Conditions,” J. Mater. Chem., 8(3), pp. 743-750, Mar. 1998.*
Grun et al., “The Synthesis of Micrometer-and Submicrometer-Size Spheres of Ordered Mesoporous Oxide MCM-41,” Advanced Materials, 9(3), pp. 254-257, 1997.*
Schacht et al., “Oil-Water Interface Templating of Mesoporous Macroscale Structures,” Science, vol. 273, pp. 768-771, Aug. 1996.*
Lewis, Hawley's Condensed Chemical Dictionary, Twelfth Edition, p. 1035, 1993.
Lin Hong-Ping
Mou Chung-Yuan
Chinese Petroleum Corp.
Knobbe Martens Olson & Bear LLP
Sample David R.
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