JPH0761857B2 - Silicate / polymer composites, silicate compacts and methods for their production - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silicate / polymer composite, a molded product of the silicate obtained via the composite, and a method for producing them.

[0002]

2. Description of the Related Art Zeolite, which is a typical example of silicate, is
It is composed of crystalline hydrous aluminosilicate and structurally has many pores at the molecular level. Generally, zeolite is obtained as a microcrystalline powder by hydrothermal synthesis, but since the size and shape of pores differ depending on the ratio of silicon and aluminum and the synthesis conditions, the synthesis conditions and structure, and the structure and function / application It is still being actively researched because of the relationship.

The pore structure of zeolite is suitable for molecular screening, adsorption, storage / storage, activation, reaction field, etc. Since it is an aluminosilicate, it has ion exchange capacity and solid acidity. Therefore, it is widely used industrially such as adsorption / separation / purification material and catalyst. Further, in recent years, attention has been started as a sensor, an optical material, etc., and the potential demand thereof is high, and it is a material that is expected to have more and more demand in the future.

However, when zeolite is used as the above-mentioned material, it is often the case that it is not necessarily excellent in moldability, which is a major obstacle, and there is a problem that its inherent function cannot be utilized highly and multilaterally. Therefore, in order to efficiently use and apply the functions of zeolite, morphological control of zeolite, for example, research on membrane formation, fiber formation, etc. is being actively pursued.

Recently, there have been attempts to obtain zeolite as a membrane in order to improve application functions such as adsorption and separation / purification functions. For example, it has been proposed to synthesize a zeolite zeolite in the form of particles of several tens of microns to several hundreds of microns and arrange (fill) it in an organic substance to form a zeolite membrane with a thickness of several tens of microns to several hundreds of microns. ing. A method for synthesizing a zeolite membrane on a glass or porous inorganic oxide substrate has also been disclosed (Japanese Patent Laid-Open Nos. 59-23136, 63-291809, and US Pat. No. 4).
No. 800187 issued in 1989). Furthermore, the present inventors have previously proposed to easily synthesize a film composed of zeolite particles alone without using a porous oxide substrate or the like (6th Zeolite Research Group Research Presentation, November 29) ).

These methods are attracting attention because they not only improve the function of zeolite but also lead to the discovery of new functions.

[0007]

However, in the above method, since the zeolite crystals in the form of particles are synthesized and then arranged in a film form in the organic matter, the zeolite crystal fine particles are added in addition to the step of synthesizing the zeolite crystals. A step of arranging is required, and a zeolite membrane cannot be easily obtained. In addition, it was obtained that the organic substance blocks the pores of the zeolite, that the ion exchange capacity and the solid acidity cannot be adjusted sufficiently even after film formation, and that the organic substance is vulnerable to high temperatures. Zeolite membrane has a problem that it cannot withstand use at high temperature.

On the other hand, in the case of synthesizing a zeolite membrane on glass or a porous inorganic oxide substrate, there is a problem that a new solid acid appears in addition to the solid acid originally possessed by zeolite, in addition to the pore clogging by the substrate. is there. In addition, there is a problem that the crystal growth of zeolite is difficult to be uniform due to the influence of the surface structure such as irregularities and pores of the substrate, and only the zeolite of a specific structure can be formed due to epitaxy. And is involved in the reaction,
When synthesizing a membrane, it is necessary to estimate that amount, and it is not easy to synthesize the membrane. Therefore, in the technology so far, there is no example in which a uniform zeolite membrane is freely synthesized on the substrate, and it can be said that the obtained membrane also exhibits excellent performance reflecting the original properties of zeolite. I want to.

With respect to this point, the zeolite membrane obtained by the method previously proposed by the present inventors is excellent because it is a molded body made of zeolite alone, but since the connection between the zeolite particles is weak, the strength of the membrane is low. Is not enough, and also
Its form has not reached the point where it can be controlled freely.

[0010]

[Means for Solving the Problems] The inventors of the present invention have conducted earnest studies on the development of zeolite composites and molded bodies which highly possess the excellent functions originally possessed by zeolites, and the production method of their advantages. As a result, in the reaction system for producing silicic acid by the hydrothermal synthesis method, when a silicate is synthesized by allowing the presence of a cellulosic material having an active hydrogen-containing functional group, the silicate and the cellulosic material are , It was found that a silicate / polymer composite bonded through the active hydrogen-containing functional group of the cellulosic material can be obtained, and that this composite has a high function originally possessed by silicate. Furthermore, in this composite, the silicate that binds to the cellulosic material corresponds to the shape of the cellulosic material when forming a continuous layer and firing the composite. It found to give silicate molded product having a shape, and have completed the present invention based on these findings. That is, according to the present invention, it is composed of a cellulosic material having an active hydrogen-containing functional group and a silicate, and the silicate is the cellulosic material via the active hydrogen-containing functional group contained in the cellulosic material. Provided is a silicate / polymer composite characterized by being bound to a material. Further, according to the present invention, there is provided a silicate compact comprising a fired product obtained by firing the silicate / polymer composite. Further, according to the present invention, in a method for producing a silicate by a hydrothermal synthesis method, a cellulose material having an active hydrogen-containing functional group is present in the reaction system, and the produced silicate is treated with the active hydrogen-containing material. Provided is a method for producing a silicate / polymer composite, which is characterized in that it is bound to a cellulosic material via a functional group. Furthermore, according to the present invention, the composite is fired, and the cellulosic material contained in the composite is fired and removed to obtain a fired product having a shape corresponding to the shape of the composite. A method for manufacturing a silicate compact is provided.

The cellulosic material used in the present invention has an active hydrogen-containing functional group. In this case, as the active hydrogen-containing functional group, an amino group, an amide group, a hydroxyl group,
It can represent a carboxyl group, a sulfone group, a mercapto group, or the like. The cellulosic material used in the present invention preferably contains a large number of such active hydrogen-containing functional groups in the molecule. Generally, it is preferable to use a cellulosic material having an atomic ratio (H / C) of active hydrogen to carbon of 0.05 or more, preferably 0.2 or more. The cellulosic material used in the present invention is a reaction system for synthesizing silicate,
It is necessary to exhibit insolubility, and those exhibiting solubility in the reaction system can be obtained by graft-polymerizing a hydrophobic monomer, for example, styrene, ethylene, propylene, acrylic acid ester, methacrylic acid ester, or by crosslinking. It can be insolubilized before use. The cellulosic material of the present invention may have any shape, such as powder, pellet, film, plate, corrugated plate, honeycomb, fiber (thread), woven cloth, non-woven cloth, cylinder, and container. Can have various shapes such as. Examples of preferable cellulosic materials used in the present invention include materials in various forms mainly composed of cellulose or a derivative thereof, such as pulp powder, paper, filter paper, cotton thread, and cotton cloth.

The composite of the present invention can be produced by allowing the above-mentioned cellulosic material to be present in the hydrothermal synthesis reaction system for synthesizing silicate. The hydrothermal synthesis reaction for synthesizing a silicate is a well-known reaction, and its reaction temperature varies depending on the kind of the silicate to be synthesized, but the temperature is 200 ° C. or lower, usually 120 ° C. ~ 180
It is in the range of ° C. Examples of the silicate include zeolite (crystalline aluminosilicate, crystalline aluminogallosilicate, crystalline aluminoiron silicate, etc.), silicalite (crystalline silicate), and molecular sieve. The hydrothermal synthesis reaction used for producing the composite of the present invention is preferably carried out without stirring so that the hydrothermal synthesis reaction selectively proceeds on the surface of the cellulosic material. The specific composition and reaction conditions of the hydrated gel used in the reaction may be appropriately selected depending on the desired silicate. For example, in the case of synthesizing zeolite, a solution containing an aluminum compound and a silicon compound according to the desired zeolite composition, alkali hydroxide is added, if necessary an organic amine such as tetrapropylammonium bromide is added as a templating agent, The reaction is carried out at 100 to 200 ° C.
The complex of the present invention obtained by the hydrothermal synthesis reaction,
A silicate is bonded to the surface of a cellulosic material as a continuous layer, the shape of which corresponds to the shape of the cellulosic material present. For example, if the cellulosic material is sheet-shaped, a sheet-shaped composite is obtained, and if the cellulosic material is thread-shaped, a thread-shaped composite is obtained. Therefore, in the present invention, a composite having any shape can be easily obtained.

The reason why the silicate / polymer composite is obtained by allowing the presence of the cellulosic material in the hydrothermal synthesis reaction system is that the active hydrogen-containing functional group in the cellulosic material is treated by the metal ion-trapping action. A field of thermosynthetic reaction is formed, and the hydrothermal synthetic reaction proceeds smoothly in this active hydrogen-containing functional group portion of the cellulosic material,
It is considered that the generated silicate is bonded to the cellulosic material via the active hydrogen-containing functional group, and the silicate crystals grow on the surface of the cellulosic material with the bonded silicate as a nucleus. To be When the composite of the present invention is baked and the cellulosic material contained therein is removed by baking, a silicate-fired product having a shape corresponding to the composite is obtained. For example, a sheet-shaped composite gives a sheet-shaped silicate calcined product, and a thread-shaped composite gives a thread-shaped silicate calcined product. The firing temperature of the composite is 40
The temperature is 0 to 1000 ° C, preferably 500 to 600 ° C.

[0014]

The composite of the present invention has a structure in which a silicate is bonded to the surface of a cellulosic material, and has the functions of both the cellulosic material and the silicate.
This can be used as a packing material for thin layer chromatography or column chromatography, and can also be used as a gas separation membrane. As described above, the shape of the fired product of the composite of the present invention corresponds to the shape of the composite, and thus the composite of the present invention can be advantageously used as a raw material for producing a silicate compact. Further, the calcined product obtained from the composite of the present invention is composed only of silicate, but its shape should be maintained in an arbitrary shape according to the shape of the cellulosic material used for manufacturing the composite. You can
Therefore, the baked product of the composite of the present invention is widely used as a shaped product having an appropriate shape, such as a molecular sieve, an adsorbing and separating / purifying agent, an ion exchanger, and a catalyst.

[0015]

EXAMPLES Examples of the present invention will be described below. Example TPABr (tetrapropylammonium bromide) and NaOH were added to an aqueous solution containing Al (NO3) 3.9H2O and colloidal silica, and the mixture was stirred uniformly to prepare a hydrated gel. The composition of the gel is 0.1TPABr-0.05Na _{2
O- (0~0.05) Al 2 O 3} -SiO 2 - (40~1000) H 2
An O composition was prepared.

Each gel composition was treated under the conditions shown in Table 1 in the presence of various shapes of cellulosic material (filter paper).
Hydrothermal synthesis was performed using an autoclave of 0 to 300 ml to obtain a complex of ZSM-5 type zeolite and a cellulosic material.

[0017]

[Table 1]

The shape of the obtained composite depends on the shape of the cellulosic material used, and is a thread, a sheet, or a three-dimensional shape, and it can be seen that a composite of any shape can be prepared.

The composite obtained in Experiment No. 1 was washed with water, dried, and subjected to structural analysis by XRD (X-ray diffraction).
It was confirmed that the silicate contained in the composite had a ZSM-5 type zeolite structure. Further, as a result of examining a SEM (scanning electron microscope) image of a cross section of the composite obtained in Experiment No. 1, the thickness is about 500 microns,
It was observed that zeolite was intricately grown inside the filter paper. It was also observed that a relatively large size zeolite was present in the surface layer. The thickness of the filter paper used alone is about 200 μm. Further, the thickness of the composite can be arbitrarily adjusted by changing the size of the filter paper and the amount of the hydrated gel charged.

Next, even if the obtained composite is calcined at 500 ° C. to burn and remove the cellulose contained in the composite,
Its shape did not change. Therefore, according to the present invention, a zeolite compact can be easily obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuichi Niwa 1-1, Higashi, Tsukuba-shi, Ibaraki Industrial Technology Institute, Institute of Chemical Technology (72) Inventor Makoto Toba 1-1-1, East, Tsukuba-shi, Ibaraki Institute of Chemical Technology In-house (72) Inventor Kazuyuki Maeda 1-chome, Higashi 1-1-chome, Tsukuba, Ibaraki Institute of Chemical Technology, Institute of Industrial Technology (56) Reference JP-A-61-295224 (JP, A)

Claims (5)

[Claims] 1. A cellulosic material having an active hydrogen-containing functional group and a silicate, wherein the silicate is bonded to the cellulosic material via an active hydrogen-containing functional group contained in the cellulosic material. A silicate / cellulosic composite characterized in that 2. The silicate is a zeolite.
Complex of. 3. A silicate compact comprising the fired product of the composite according to claim 1. 4. A method for producing a silicate by a hydrothermal synthesis method, wherein a cellulosic material having an active hydrogen-containing functional group is present in the reaction system, and the produced silicate is treated with the active hydrogen-containing functional group. A method for producing a silicate / polymer composite, which comprises binding to a cellulosic material via a silicate. 5. The silicic acid, characterized in that the composite according to claim 1 is calcined, the cellulosic material contained in the composite is calcined and removed, and a calcined product having a shape corresponding to the shape of the composite is obtained. A method for producing a salt molded body.