Catalyst – solid sorbent – or support therefor: product or process – In form of a membrane
Reexamination Certificate
2002-06-28
2004-02-17
Dunn, Tom (Department: 1725)
Catalyst, solid sorbent, or support therefor: product or process
In form of a membrane
C502S060000, C502S064000
Reexamination Certificate
active
06693055
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a zeolite-substrate composite comprising a patterned zeolite layer and a method of preparation of the same. More specifically, the present invention relates to a method for the preparation of a zeolite-substrate composite comprising a patterned zeolite monolayer or multilayer on a substrate, which comprises forming a pattern of a linking compound on the substrate by binding a linking compound on the substrate surface followed by a selective irradiation with UV ray thereon, or by a selective coating on a portion of the substrate surface with a linking compound or a blocking compound such as octadecyltrichlorosilane, or by a selective deposition of a metal such as platinum on the substrate surface followed by binding a linking compound thereon, and combining selectively zeolite or zeotype molecular sieve (hereinafter, referred as to “zeolite” or “molecular sieve”) along with said pattern, wherein said substrate is selected from a group consisting of a substance having surface hydroxyl groups, a metal capable of being reacted with thiol group (—SH) or amino group (—NH
2
) and a polymeric material having various surface functional groups. The present invention also relates to the zeolite-substrate composite prepared thereby.
BACKGROUND ART
Molecular sieves including zeolite are important materials, which have been employed widely in the household item level and the industrial field. Zeolite generally presents in the form of fine powder, which gives both advantages and disadvantages for using zeolite. Combining those zeolite particles firmly with various substrates through chemical bond, a wide industrial applicability of zeolite can be expected.
Further, it can be said that it is significant to adjust the zeolite so as to have a uniform orientation to the substrate as it can induce new physical properties expectedly. Still further, if zeolite particles are combined to the substrate surface so as to have a selective and/or uniform orientation, novel characteristics that have never been found in the conventional material would be expected and an epoch-making development may be achieved.
“Zeolite” is a generic name of crystalline aluminosilicate, which constitutes the pore skeleton of zeolite molecules and bears an anionic charge for each aluminum atom. Cations for offsetting such anion charges are present within the pore space and the remaining pore space is filled with water. The three dimensional pore structure of the zeolite molecule varies depending on the shape and size of the pore, and the pore diameter is usually determined by size of the molecule. Therefore, based on the shape and size of the pore, zeolite has a shape selectivity for a molecule entering into the pore. In this connection, zeolite is called as a molecular sieve.
Zeolite (or molecular sieve) or analogous molecular sieves (hereinafter, referred to as zeolite or its analogs) show diverse chemical and physical properties depending on its chemical composition, structure, pre-treatment method, etc. Especially, modified zeolite in which protons are replaced with other cations is widely used as a cracking catalyst of crude oil in the petrochemical industry, thanks to its resistance to high temperature. Further, zeolite is widely used as a water-absorbing drying agent, adsorbent, gas-purifying agent, ion exchanger, additives for detergent, soil improving agent or the like. An extensive study is now being made on its application as a sensor carrier.
Meanwhile, there are known many other zeolite-like molecular sieves (or zeotype molecular sieves) wherein a part or all of silicon (Si) and/or aluminum (Al) atoms constituting the structural skeleton of zeolite molecule are replaced with other elements. For example, a mesoporous silica (MCM-series mesoporous silica and silicalite, etc.) in which aluminum atoms are completely eliminated, an alpo(AlPO
4
)-type molecular sieve in which silicon atoms are replaced with phosporous atoms, and other molecular sieve or its analog wherein skeleton metal atoms are partly replaced with various metal atom such as Ti, Mn, Co, Fe, Zn, etc., have been developed and widely used.
For better utilization of zeolite or its analogs, studies have been carried out to develop methods of attaching zeolite particles to the surface of substrates such as glass, ceramics, polymeric materials, metal, etc. [L. C. Boudreau, J. A. Kuck, M. Tsapatsis,
J Membr. Sci.
1999, 152, 41-59; Z. Li, C. Lai, T. E. Mallouk,
Inorg. Chem.
1989, 28, 178-182; L. C. Boudreau, J. A. Kuck, M. Tsapatsis,
J. Membr. Sci.
1999, 152, 41-59; J. C. Jansen, D. Kashchiev, A. Erdem-Senataler,
Stud. Surf, Sci. Catal,
1994, 85. 215-250; R. Althoff, K. Unger, F. Shuff,
Microporous Mater,
1994, 2, 557-562].
However it is not easy to perfectly control the thickness and orientation of a zeolite monolayer through conventional methods. The inventors have developed a simple and economic method for the preparation of a composite of substrate-linking compound-zeolite by chemically changing the surface of the substrate or zeolite by using a linking compound having functional groups capable of reacting with the substrate or zeolite, respectively. [See: PCT/KR00/01001 with claiming a priority based on Korean Patent Application No. 2000-19667 (filed on Apr. 14, 2000)].
On the other hand, numerous studies have been carried out in respect of the formation of the pattern on the surface of substrates such as glass, ceramics, polymeric materials and metal. As to conventionally known methods for forming a pattern, the following three methods can be exemplified basically.
The first method is a selective irradiation wherein UV ray is irradiated with a photomask to selectively form a pattern. The second method is a stamping method wherein a pattern is previously prepared onto a cast by using polydimethylsiloxane (PDMS), a linking compound or a blocking compound such as octadecyltrichlorosilane is applied onto the cast, and said cast is stamped onto the substrate to form said pattern on the substrate. The third method is a selective metal deposition wherein a metal grid is stuck to a substrate and a deposited layer of a metal such as platinum is selectively formed on the substrate to form a pattern.
As set forth herein above, such technology wherein a surface is modified by forming a pattern on a substrate so that the chemical reactivity of the surface of the substrate varies along the pattern formed on said substrate is well known. There are many technical difficulties in modifying the surface of zeolite so as to have a chemical reactivity to combine the zeolite particles chemically onto a substrate.
The inventors have already achieved a great development of the chemical procedure by modifying a chemical reaction that happens in a solution state so that it can happen at the surface of a material. Further, the inventors have extensively studied in order to produce various composites by utilizing the methods thus developed.
As a result, the inventors have developed a method for the formation of a patterned monolayer or multilayer of zeolite having an excellent durability and orientation, which comprises forming a pattern on the substrate by means of UV ray, a blocking compound, a metal (e.g., platinum) deposition, etc. and chemically combining of zeolite onto the patterned surface of the substrate.
As set forth hereinabove, it has been well known to modify the surface so as to the different chemical reactivity along the pattern by forming a pattern thereon by means of UV ray, a linking or blocking compound (e.g., octadecyltrichlorosilane), a metal (e.g., platinum) deposition, etc. However, it has never been reported to form a patterned zeolite layer on surface-modified substrate.
It is now found that, when the method described in said Korean Patent Application No.2000-19667 filed by the inventors, i.e., when the method of combining zeolite to a substrate via a chemical bonding is employed, it is possible to laminate on a substrate on which a pattern has been formed a zeolite layer alo
Chun Yu-Sung
Ha Kwang
Lee Goo-Soo
Lee Yun-Jo
Park Yong-Soo
Ildebrando Christina
Nixon & Vanderhye P.C.
Sogang University Corporation
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