JP2000007323A - Production of microporous material, microporous material and separation of fluid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To readily produce a microporous material corresponding to the form of use by bringing an alkylamine into contact with an alkoxysilane in pore parts of a porous material, providing a reactional product in the pore parts and then removing the alkylamine. SOLUTION: A tetra-substituted type is preferred as an alkoxysilane and, e.g. tetraethoxysilane is cited. An alkylamine is the one having a linear 5-11C alkyl group and, e.g. ethylamine is cited. Cordierite, etc., can be used as the porous material. The porosity thereof is preferably 0.2-0.5 and the pore diameter is preferably 0.05-5 μm. The alkylamine is preferably introduced into the pore parts of the porous material before the reaction of the alkoxysilane with the alkylamine. The alkylamine is eliminated from the porous material by a method for forming a porous structure in the pore parts by the reaction, then increasing the temperature and decompressing the interior of the pores or a method, etc., for extracting and washing the alkylamine with an organic solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porous material and a fluid separation method, and more particularly, to a material having straight tubular pores used as a component separation of various fluids, a reaction catalyst or a catalyst carrier, and a method for separating such a material. The present invention relates to a method for separating fluid such as carbon dioxide used.

[0002]

BACKGROUND OF THE INVENTION A material called mesoporous silica was invented in 1992 by Mobile. This material has pores having a pore size of 1.5 to 10 nm, and is considered to be industrially usable as a catalyst material and an adsorbent. These have a regular cylindrical (straight tubular) pore arrangement and are characterized by having a large specific surface area, high heat resistance, and the like. MCM-41 is a typical example. Then, F
An analogous substance called SM-16, HMS has been synthesized.

[0003] MCM-41 is synthesized from silica sol and alkyltrimethylammonium as raw materials under hydrothermal conditions at 100 ° C or higher. 10 to 16 carbon atoms of the alkyl group
By changing the pore size to 1.5 to 1
0 nm [J. S. BECK,
J. C. VARTULI, J .; ROTH, M .; E. FIG. LE
ONOWICZ, C.I. T. KRESGE, K .; D. SC
HMITT, C.I. T-W. CHU, D.A. H. OLSO
N, E .; W. SHEPPARD, S.M. B. MCCULL
EN, J.A. B. HIGINS, and J.M. L. SC
HLENKER, J.A. Am. Chem. Soc. , 11
4, 10834 (1992)].

[0004] FSM-16 is introduced by ion exchange alkyltrimethylammonium in aqueous solution at about 50 ° C. relative to phyllosilicate kanemite _{(HSi 2 O 5 · 3H 2} O), then fired at about 700 ° C. Is obtained. MC
As in the case of M-41, by changing the number of carbon atoms of the alkyl group to about 10 to 16, the pore diameter becomes 1.5 to 10
nm [S. INAGAKI, A .; KO
IWAI, N .; SUZUKI, Y .; FUKUSHIM
A, and K. KURODA, Bull. Chem.
Soc. Jpn. , 69, 1449 (1996)].

On the other hand, HMS can be synthesized at room temperature using tetraethoxysilane and alkylamine as raw materials. By changing the carbon number of the alkyl group to about 10 to 12, the pore diameter can be controlled between 2.5 and 3 nm [P. T. TANEV, M .; CHIBWE, an
d T. J. PINNAVAIA, Nature, 36
8, 321 (1994)].

Apart from these, the present inventors have found a novel silica-based material. For such new materials,
It is described in Japanese Patent Application No. 9-291303 (not disclosed at the time of filing the present application). The production method uses alkoxysilane and an alkylamine having 6 to 11 carbon atoms in the alkyl group as raw materials. The material thus obtained is 1.0-
It has straight tubular pores with a pore size of 2.2 nm and a very narrow pore size distribution.

[0007]

However, all of these materials are obtained in powder form. Therefore, in general, for use in an industrial separation process or a catalytic reaction process, they are formed into granules or agglomerates and then packed in a fixed bed for use. Therefore, an object of the present invention is to provide a method for manufacturing a pore material that can easily produce a pore material corresponding to a use mode. Also, the present invention
It is an object of the present invention to provide a porous material capable of directly or easily obtaining a predetermined shape corresponding to a use form. Also,
An object of the present invention is to provide a method for separating a fluid using a novel pore material.

[0008]

Means for Solving the Problems The present inventors have studied in detail the reaction steps for producing a porous material using alkoxysilane and tetraalkylamine as raw materials, and as a result, completed the following invention. That is, the present invention provides a method for producing a porous material, which comprises contacting an alkylamine and an alkoxysilane in a pore of a porous body to obtain a reaction product in the pore, and thereafter removing the alkylamine. It is. According to this production method, a pore structure is formed in the pores of the porous body. In this production method, a method for producing a pore material in which the alkylamine has 5 to 11 carbon atoms is also provided. In this production method, the alkoxysilane is a pore using one or more of tetraethoxysilane, tetrabutoxysilane, tetrapropoxysilane, triethoxymethoxysilane, trimethoxyethoxysilane, and diethoxydimethoxysilane. A method of making the material is also provided.

Further, the present invention provides a porous material having a porous structure in the pores of a porous body. According to this microporous material, since the microporous structure is provided in the pores of the porous body as a carrier, the microporous material can be processed as it is or easily into a use form as a separation material or a catalyst.

[0010] The present invention also provides a fluid separation method for separating a component in a fluid by bringing a fluid mixture into contact with a pore material having a pore structure in the pores of a porous body. In this separation method, the fluid mixture contains carbon dioxide, and a fluid separation method for separating carbon dioxide is provided.

[0011]

Embodiments of the present invention will be described below in detail. The pore material obtained by the method for producing a pore material of the present invention has a pore structure in the pores of the porous body. It is preferable that the pore structure is not formed by filling the pores with a powder of a pore material or the like, but is formed and reacted in the interior. This is because it is more preferable as a pore material in terms of pore filling property and density. The formation of the pore structure in the pores of the porous body can be made from an alkylamine and an alkoxysilane. The pore structure is composed of a silica-based pore structure using an alkylamine as a template for a capillary.

(Production of Porous Material) To obtain the porous material of the present invention, a porous body and a raw material for forming a pore structure are required.

(Raw Material of Pore Structure) Two kinds of raw materials are used for synthesizing the pore structure in the pores of the porous body. The first material is alkoxysilane which is a source of silicon and oxygen forming the skeleton of the present material. As the alkyl group of the alkoxysilane, a linear, branched, or cyclic alkyl group can be used. As the alkoxysilane, a tetrasubstituted alkoxysilane can be preferably used. The alkyl groups of the alkoxysilane may be all the same or may be composed of different alkyl groups. Preferred examples of the alkoxysilane include, for example, tetraethoxysilane, tetrabutoxysilane, tetrapropoxysilane, triethoxymethoxysilane, trimethoxyethoxysilane, diethoxydimethoxysilane, dimethoxydiethoxysilane, and the like. As the alkoxysilane, one kind or a combination of two or more kinds can be used.

The second raw material is an alkylamine which is a so-called template agent, which functions as a template for determining the pore diameter of the material. As the alkyl group of the alkylamine, a linear, branched, or cyclic alkyl group can be used. Preferably, it is a linear alkyl group. Note that the alkylamine is preferably a primary amine. The carbon number of the alkyl group is a factor that controls the diameter of the capillary. In order to obtain a capillary having a smaller diameter, it is preferable to use an alkyl group having a small number of carbon atoms. As the alkyl group, one having 5 to 11 carbon atoms can be preferably used. The alkylamine that can be preferably used in the present invention is a straight-chain tetraalkylamine having an alkyl group having 5 to 11 carbon atoms, and specific examples thereof include, but are not limited to, ethylamine, propylamine,
Butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine and undecylamine. The alkylamine is 1
Species can be used alone or in combination of two or more.

(Porous Body) As the porous body, cordierite, mullite, silicon nitride, silicon carbide, alumina, zirconia, titania and the like can be used. The porosity of the porous body is preferably from 0.2 to 0.5, but may exceed 0.5 as long as the strength is secured. Further, a preferable pore diameter is 0.05 to 5 μm. The smaller the pore size, the better the packing state of the pore structure. The form of the porous body is preferably a flat plate or a circular tube.

(Production Method of Capillary Material) Prior to the reaction between the alkoxysilane and the alkylamine, it is preferable to introduce the alkylamine into the pores of the porous body. When the alkylamine is introduced, it is preferably in the form of an aqueous suspension suspended in an aqueous solvent. The aqueous solvent is a solvent mainly composed of water, but is more preferably water. The aqueous solvent may contain other solvents other than water, such as ethanol, in consideration of the solubility of the alkylamine. The preparation in the aqueous suspension is performed at a temperature not lower than the temperature at which the alkylamine to be suspended is liquefied. However, in the synthesis of a pore structure having a pore diameter of 1.8 nm or less, heating is generally not required. A suspension can be prepared. The mixing ratio of the alkylamine and the aqueous solvent (alkylamine: aqueous solvent) is 1: 1 to 1: 1 in molar ratio.
Preferably it is 000. More preferably,
1:10 to 1: 300, more preferably 1:
20 to 1: 100.

Next, this suspension is introduced into the pores of the porous body. As the method of introduction, various conventionally known methods such as spraying the suspension on the porous body or dipping (dipping) the porous body into the suspension can be used. At the time of introduction, removing the air in the hole under reduced pressure is particularly effective for filling the hole with the suspension.

By bringing the alkylamine in the pores of the porous body into contact with the alkoxysilane, a pore structure can be formed in the pores of the porous body. When the alkylamine has already been introduced into the pores of the porous body, the method of adding the alkoxysilane may be a method of spraying a stock solution of the alkoxysilane or a method of supplying steam. The molar ratio of the alkoxysilane to the alkylamine in the pores of the porous material (alkoxysilane: alkylamine) is 1:10.
0-10000: 1 is preferred. A desirable molar ratio at which the reaction proceeds smoothly is 1: 1 to 10,000: 1, more preferably 100: 1 to 1000: 1. When tetraethoxysilane is used as the alkoxysilane and pentylamine is used as the alkylamine, the preferred molar ratio (tetraethoxysilane: pentylamine) is 10
It is preferably 0: 1 to 5000: 1, more preferably 500: 1 to 2000: 1. Most preferably, it is about 1000: 1. In order to promote the contact between the alkoxysilane and the alkylamine in the porous material pores, it is preferable that the porous material is suctioned under reduced pressure from the side opposite to the side on which the alkoxysilane is supplied to the porous material.

The reaction by the contact of both components, that is, the arrangement and polymerization reaction of the alkoxysilane using the alkylamine as a template proceeds. The reaction temperature range is higher than the freezing point of the alkylamine used and lower than the boiling point of water. As the reaction proceeds, the pores in the porous body are filled with the reaction product. Above a certain loading, the alkoxysilane will not pass through the porous plate. By allowing the mixture to stand for 0.1 to 20 hours from this point, the reaction product is formed in the hole with a good filling rate. Usually, alkoxysilane is added from the surface side of the porous body, and the alkoxysilane gradually penetrates into the porous body through the pores of the porous body and reacts with the alkylamine to generate a reaction product. I will do it. Therefore, a reaction product is more easily formed on the alkoxysilane addition side, and a layer having a high concentration of the reaction product is easily formed on the alkoxysilane addition side of the porous body. When such a layer is formed, the layer in the porous body can be used as a film. Further, depending on the shape of the porous body and the method of adding the alkoxysilane, a reaction product can be obtained from the entire porous body. For example,
For a thin-film porous body having a thickness that allows alkoxysilane to sufficiently penetrate, for a granular porous body having such a particle size,
A reaction product can be obtained over the entire porous body by a usual addition method of alkoxysilane. Furthermore, in order to penetrate the alkoxysilane into the porous body,
It is more effective if vacuum suction or the like is performed. The reaction product can be penetrated into the porous body in the range of 0.1 to 100 μm, and it is relatively easy to impart a pore structure in this range.

In this way, after the alkoxysilane is applied to the porous body to generate a reaction product in the pores, the alkylamine is desorbed from the porous body. Examples of the separation method include a method of desorption under reduced pressure by increasing the temperature, a method of extraction and washing with an organic solvent, and a method of burning and removing by heating and introducing oxygen. The first two methods are preferable in that the alkylamine can be recovered. However, in order to remove a trace amount of residual amine, it is more preferable to combine with a combustion removal method.

In the case of the combustion removal method, by heating in an air stream containing oxygen or the like, the alkylamine can be removed and the solvent can be removed, and at the same time, a porous body having a pore structure in the pores can be obtained. The heating temperature is preferably 500 ° C. or higher. In the process of raising the temperature to 500 ° C., decomposition of the alkylamine starts. Further, in the process of increasing the temperature, combustion is started. If the oxygen concentration and the rate of temperature rise are too high in the airflow, local heat rise of the capillary structure due to combustion heat may occur, resulting in structural destruction of the material. For this reason, it is preferable to control the heating rate, the oxygen concentration, and the heating temperature. By maintaining the temperature at 500 ° C. or higher, alkylamines (particularly primary amines) and their decomposition residues, such as carbon, are removed.

When the combustion removal method is not carried out, the residual porous material after the reaction from which the alkylamine has been removed is further removed from the reaction product by heating under reduced pressure or elevated temperature, or a combination thereof, Further, by heating in an air stream containing oxygen or the like, a porous body having a pore structure in the pores can be obtained. The heating temperature is preferably 500 ° C. or higher. At the time of such heating, it is preferable to control the heating rate, the oxygen concentration, and the heating temperature for the same reason as in the case of performing the combustion removal method.

In this manner, a porous body having a pore structure in the pore can be obtained. Further, by repeating the above-described steps, that is, by repeating the steps of providing an alkylamine, providing an alkoxysilane, removing an alkylamine, removing a solvent, and heating, the pores of the porous body have a higher density. A pore structure can be provided. In addition, the formation region of the pore structure can be increased. Note that, after the alkylamine is previously applied to the pores of the porous body, the alkylamine and the alkoxysilane are brought into contact with each other to obtain a reaction product in the pores and obtain a pore structure in the pores. However, by contacting the alkylamine with the alkoxysilane in the pores of the porous body, a pore structure can be formed in the pores without such a step. For example, by applying an alkylamine and an alkoxysilane almost simultaneously, for example, in a mixed liquid state to the pores of the porous body,
A reaction product can be obtained in the pores of the porous body to form a pore structure.

The obtained pore material has a pore structure formed in the pores of the porous body. That is, since the pore structure is held by the porous body, the pore structure is more stable and the strength is improved as compared with the case where only the pore structure is used. Such a porous material can be used as it is for separation, for a catalyst, or for a catalyst carrier, depending on the form of the porous body used. Further, it is also easy to pulverize and use the pulverized material as a filler or as a molding material. That is, processing is easy.

The pore structure obtained in the pores of the porous body is
It is preferable that the straight tubular pores are arranged. The straight tubular pore structure can be confirmed by observing a gas adsorption / desorption isotherm.

The obtained pore material is used for various applications. For example, it has selectivity based on affinity for a specific component of a pore structure formed in a pore portion, and thus can be used in various separation processes as an adsorbent material or a permeable membrane material. Further, it can be used as an adsorption separation process, a membrane separation process, a selective reaction catalyst, a membrane reactor, or the like based on the pore diameter of the pores. Furthermore, various uses can be provided by combining the above selectivity with the pore diameter. In particular, the present porous materials are useful for carbon dioxide separation processes by utilizing their selective affinity for a characteristic component such as carbon dioxide.

[0027]

According to the method for producing a porous material of the present invention,
It is possible to provide a manufacturing method capable of easily manufacturing a pore material corresponding to a use mode. According to the pore material of the present invention, it is possible to provide a pore material capable of directly or easily obtaining a predetermined shape corresponding to a use form. According to the fluid separation method of the present invention, it is possible to provide a method of separating a fluid using a novel pore material.

[0028]

The present invention will be described below with reference to specific examples. Note that the present invention is not limited to the following embodiments. (Example 1) At 25 ° C, 13.5 mmol of alkylamine was added to 26.6 ml of deionized water,
An aqueous suspension of the alkylamine was prepared. As the alkylamine, three kinds of (a) nonylamine (9 carbon atoms), (b) hexylamine (6 carbon atoms), and (c) pentylamine (5 carbon atoms) were used. For each suspension, a porosity of 0.
35 and a silicon carbide plate (1) having an average pore diameter of 200 nm.
0 mm × 10 mm × 1 mm thick), and the inside of the hole of the silicon carbide plate was filled with the suspension. After the silicon carbide plate after filling with the suspension was mounted on a filter, 50 mmol of a stock solution of tetraethoxysilane was added from above. The silicon carbide plate was sucked from the bottom of the plate to promote the introduction of tetraethoxysilane. When the tetraethoxysilane stock solution did not pass through the silicon carbide plate, the suction operation was completed, and the plate was allowed to stand at 25 ° C. for 20 hours.

Next, this silicon carbide plate was put into 200 ml of ethanol, and ethanol was introduced into the plate by vacuum degassing treatment and pentylamine was extracted. Thereafter, heating is performed in an air atmosphere at 500 ° C., and the above-described series of manufacturing steps is repeated twice to form a silicon carbide plate-supported pore material having a pore structure in a hole on one surface side of the silicon carbide plate ( A), (B) and (C) were obtained. In the pore materials (A) to (C), the region where the pores were formed was in a range of about 20 μm on the surface side of the silicon carbide plate.

The pore material 77 obtained in Example 1
FIG. 1 shows a nitrogen adsorption / desorption isotherm of the low pressure section at K. From FIG. 1, the pore materials (A), (B), and
The adsorption isotherm and the desorption isotherm of (C) almost coincide with each other, and no hysteresis is observed, suggesting the presence of a pore structure of a straight tube. Further, in (A), the relative pressure of nitrogen P / P
The steep rise seen at 0 = 0.1 and also at (B) up to the relative nitrogen pressure P / P0 = 0.1 clearly supports this suggestion.

FIG. 2 shows the pore size distribution of the pore material obtained in Example 1. In FIG. 2, the pore material (A) has a diameter of 1.7 nm, (B) has a diameter of 1.0 nm, and (C)
Has a relatively sharp pore size distribution centered at 0.6 nm in diameter.

Specific surface areas of the porous materials (A), (B) and (C) obtained by analyzing the adsorption-desorption isotherm shown in FIG.
The pore volume is shown in Table 1 together with the pore diameter.

[Table 1]

(Example 2) For the porous materials (A) to (C), gas permeation at 25 ° C. was performed using an evaluation apparatus shown in FIG. 3 using pure gases Ar, O ₂ , N ₂ , CO ₂ , and SF ₆ . The properties were measured. The area fixed to the evaluation device is about 100mm ²
Five kinds of pure gases were supplied to each of the samples (pore materials (A) to (C)) at an absolute pressure of 6 kgf / cm ² , and the permeation flow rate of the gas permeating the membrane was measured by a soap membrane flow meter.
As a result, it was found that in any of the pore materials (A) to (C), the permeation flow rate of CO ₂ was larger than that of any of the pure gases.

Table 2 summarizes the permeation flow rates of the pure gases obtained in Example 2.

[Table 2]

From these results, it can be seen that the pore materials (A) to (C)
It was confirmed that each of them could selectively permeate carbon dioxide gas, and was found to be useful for separating and recovering carbon dioxide gas.

[Brief description of the drawings]

FIG. 1 is a diagram showing a nitrogen adsorption / desorption isotherm of a low-pressure portion of pore materials (A), (B), and (C).

FIG. 2 is a view showing a pore distribution of pore materials (A), (B) and (C).

FIG. 3 is a view showing a gas permeability evaluation apparatus.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Isao Tateyama 2-4-1 Rokuno, Atsuta-ku, Nagoya-shi, Aichi F-Term in the Fine Ceramics Center 4D012 BA01 CA03 CB09 CE02 CF02 CG03 CG05 CK07 4G066 AA20C AA21C AA22B AA42A AA42C AA51C AA66C AA72C AB13A AB18A AB18B BA24 BA36 CA35 DA05 FA12 FA22 4G069 AA01 AA03 AA08 BA01B BA04B BA05B BA13B BA21C BA22A BA22B BB01B BB11B BB15B BD04B BD05B BD06B BE14C BE32C DA05 EA11 EC02Y EC03Y EC06Y EC11Y EC18Y EC19 FA02 FB14 FB16 FB20 FB24 FB30 FB35 FB36 4G073 BB45 BB58 BD03 BD18 CZ54 FB01 FB42 UA01 UA02 UA06

Claims (5)

[Claims] 1. A method for producing a porous material, comprising contacting an alkylamine with an alkoxysilane in a pore of a porous body to obtain a reaction product in the pore, and then removing the alkylamine. 2. The method according to claim 1, wherein the alkylamine has 5 to 11 carbon atoms. 3. The method of claim 1, wherein one or more of the group consisting of tetraethoxysilane, tetrabutoxysilane, tetrapropoxysilane, triethoxymethoxysilane, trimethoxyethoxysilane, and diethoxydimethoxysilane is used as the alkoxysilane. 2. The method for producing a separation permeable membrane according to item 1. 4. A porous material having a porous structure in the pores of a porous body. 5. A fluid separation method for separating a component in a fluid mixture by contacting a fluid mixture with a pore material having a pore structure in pores of a porous body.