WO2012124727A1

WO2012124727A1 - Machinable zeolite bulk body, method for producing same and hydrothermal synthesis reaction solution therefor, and application therefor

Info

Publication number: WO2012124727A1
Application number: PCT/JP2012/056535
Authority: WO
Inventors: 三宅　通博; 亀島　欣一; 俊介西本; 栄作猪木
Original assignee: 国立大学法人岡山大学
Priority date: 2011-03-14
Filing date: 2012-03-14
Publication date: 2012-09-20
Also published as: JP6052749B2; JPWO2012124727A1; JP2016052997A; JP5858492B2

Abstract

This machinable zeolite bulk body, in which no binder is used, is characterized in comprising 50-100 mass% of a zeolite component (A) and 0-50 mass% of a silica component (B) made of α-SiO₂ and/or amorphous SiO₂, the tensile strength thereof being at least 3 MPa or the flexural strength thereof being at least 3 MPa. This zeolite bulk body can be either hydrophobic (Si/Al ratio at least 3) or hydrophilic (Si/Al ratio ranging from 1 to less than 3), and can be produced by running a hydrothermal synthesis treatment for 6 hours to 10 days at a temperature of 80-225°C on a hydrothermal synthesis reaction solution containing a silica source (a), and, per mole of silica (SiO₂) in the silica source: 0.1-3.0 moles of an alkali metal component (b), in terms of the amount of alkali metal atoms; 0-0.7 moles of an alumina source (c), in terms of the amount of alumina (Al₂O₃); 0-0.15 moles of an organic template (d); and 5-50 moles of water (e).

Description

Zeolite bulk having machinability, reaction solution and production method thereof for hydrothermal synthesis, and use thereof

The present invention relates to a zeolite bulk body that can be machined and a method for producing the same. More specifically, the present invention relates to a zeolite bulk body having a strength capable of being machined without using a binder, and a simple production method using hydrothermal processing.

Zeolites that are useful as industrial and environmental materials are generally obtained as powdered solids by hydrothermal synthesis, but research on the production of membranous zeolites and bulk zeolites has been actively conducted in order to utilize their functions to a higher degree. Yes.

When zeolite is used as a bulk body, it is difficult to form a zeolite powder into a bulk body by a sintering method. Therefore, conventionally, an inorganic binder (inorganic oxide, clay, etc.) or an organic binder ( (Thickeners such as cellulose derivatives) have been used. For example, in Patent Document 1 (Japanese Patent Laid-Open No. 2000-126602), zeolite powder is formed into a pellet using a binder such as silica, alumina, titania, etc., and then palladium is uniformly dispersed and supported on the pellet. For this reason, a method for producing a palladium-supported zeolite shaped catalyst, which requires pretreatment with ammonia water and post-treatment by rapid drying of hot hot air, is disclosed.

However, in the bulk body obtained by such a method using a binder, the fine structure of the zeolite is buried in the binder, the original adsorption and ion exchange ability may not function, and the performance may be greatly impaired. The content of zeolite is also reduced. In addition, when an organic binder is used, it cannot be used at a high temperature, and is vulnerable to acids and alkalis.

On the other hand, a method for producing a zeolite bulk body by using hydrothermal treatment without using the problematic binder as described above has also been proposed.

For example, in Patent Document 2 (Japanese Patent Laid-Open No. 6-183725), a synthetic NaX-type zeolite powder, kaolin-type clay and sodium hydroxide are mixed and molded, and the resulting molded body is dried and fired, In producing a binderless X-type zeolite molded body by contacting with a mixed aqueous solution of sodium hydroxide and sodium silicate, by using the kaolin-type clay having an average particle diameter of 1.5 μm or more, containing the X-type zeolite A method for producing a binderless X-type zeolite compact having an amount of 98 wt% or more is disclosed.

Patent Document 3 discloses that 20 to 35 parts by weight of kaolin clay and 100% by weight of zeolite (X-type or A-type powder) and an inorganic dispersant (condensed phosphorus) in which the aqueous solution is alkaline and highly water-soluble. Acid zeolite, aluminate, etc.) after calcining a zeolite bead molded body formed by rolling granulation from a mixture of 4 to 10 parts by weight or / and 0.5 to 5 parts by weight of a cellulose derivative, By making the binder-less by bringing it into contact, the zeolite content rate is 95% or more, and the average value of the pressure strength of particles having a particle size of 1.7 mm or more among all particles is 6 kgf or more. A method for producing a binderless zeolite bead compact is disclosed.

In the methods described in

Patent Documents

2 and 3, the mixture of zeolite powder and kaolin-type clay is fired into a sintered body, and then the kaolin-type clay is converted into zeolite by hydrothermal treatment in an alkaline aqueous solution. Thus, a binderless zeolite compact is produced. However, these methods are complicated including raw material mixing and molding steps, firing steps, hydrothermal treatment steps using an aqueous sodium hydroxide solution, and the like.

Patent Document 3 describes that a zeolite bead molded body having strong physical properties (pressure strength) required for a dry dehydrating agent can be produced by the method described in the document. It is not described that the molded body has physical properties that can be machined without causing brittle fracture. In particular, the paragraph [0035] states that in order to obtain a molded body strength of 6 kgf or more, it is preferable that the range of 1.7 to 2.4 mm is a zeolite bead molded body of 90% or more. A bulk body having a size larger than this and a strength capable of being machined and a method for producing the same are not described in the document. Patent Document 2 does not specifically describe the strength physical properties of the zeolite molded body obtained by the method described in the document.

Patent Document 4 (Japanese Patent Application Laid-Open No. 2001-58817) discloses a formula Si ₁ Al _x M _y obtained by supporting a raw material containing an aluminum component, an alkali metal component, and a tetraalkylammonium component on a silica molding. (SDA) _z (wherein M represents an alkali metal, SDA represents tetraalkylammonium, x represents 0.0001 to 0.5, y represents 0.0001 to 1, and z represents a range of 0.001 to 1) The aluminosilicate precursor represented by the formula (2) is brought into contact with saturated water vapor to have a ZSM-5 type crystal structure, and the composition ratio (atomic ratio) between silicon and aluminum constituting the crystal structure is , All aluminum in which aluminum is in the range of 0.0001 to 0.5 with respect to silicon 1 and the aluminum content outside the crystal lattice is contained in the molded body Is 3% or less, a method for producing a binderless crystalline aluminosilicate molded is disclosed.

Patent Document 5 (Japanese Unexamined Patent Application Publication No. 2009-190915) discloses that a silica molded body containing an alkali metal component and a quaternary ammonium salt and further supporting a raw material component containing an aluminum component as necessary is brought into contact with water vapor. Thus, when producing a binderless zeolite molded body, a silica molded body having a pore volume of 0.3 to 0.55 cc / g is used, and the supported amount of quaternary ammonium salt is further increased in the silica molded body. There is provided a method for producing a binderless zeolite molded body having a ZMS-5 crystal structure having a mechanical strength of 20 N or more by adjusting so as to be in the range of 0.001 to 0.02 mol with respect to silicon contained. It is disclosed.

In the methods described in

Patent Documents

4 and 5, the binderless zeolite molded body is produced by hydrothermal synthesis treatment of a silica molded body as a base on which other raw material components are supported. The mechanical strength of the resulting zeolite molded body depends on the mechanical strength of the silica molded body used as a raw material (see, for example, paragraph [0023] in Patent Document 5), but the mechanical strength is lowered through the manufacturing process. It is inevitable. And, it is described that a zeolite molded body having a certain mechanical strength that does not cause problems such as destruction when a zeolite molded body is filled in a reactor as a catalyst can be obtained (for example, Patent Document 5 [0037]). Paragraph), it is not described that the zeolite molding has physical properties that can be machined without causing brittle fracture.

In Patent Document 6 (Japanese Patent Laid-Open No. 7-89716), an aqueous mixture comprising colloidal silica as a silica source, an alumina source, an alkali metal source, a tetrapropylammonium salt as a crystallization agent and water is enclosed in a pressure vessel. The synthesized zeolite is membranous ZSM-5, characterized in that it is heated to a hydrothermal synthesis temperature at a rate of 0.1-5 ° C / min and maintained at a hydrothermal synthesis temperature of 160-200 ° C. A process for producing a membranous synthetic zeolite is disclosed. However, the zeolite obtained by the method described in this document is in the form of a film to the extent that a zeolite bulk body having strength that can be machined can be obtained, or hydrothermal synthesis from which such a zeolite bulk body can be obtained. There is no description or suggestion that a reaction solution can be prepared. As can be seen from the additional test results shown later as comparative examples, both the “film-like” zeolite obtained in Example 11 of Patent Document 6 and the “lumpy” zeolite obtained in Comparative Example 2 have machinability. It is a substance which does not correspond to the zeolite bulk body of the present invention which is not present.

JP 2000-126602 A JP-A-6-183725 JP 2002-68732 A JP 2001-58817 A (Patent No. 34442348) JP 2009-190915 A Japanese Patent Laid-Open No. 7-89716

If a zeolite bulk body having a strength that can be machined without causing brittle fracture is obtained, it is possible to further expand the use of zeolite, but it has such physical properties and without using a binder. A relatively large bulk body that retains the original function of zeolite has not been obtained so far. An object of the present invention is to provide a binder-free (binderless) zeolite bulk body having a strength capable of machining and a method for producing such a zeolite bulk body as simple as possible.

By using a reaction solution containing water, a silica source, an alumina source, an alkali metal component, and an organic template as a structure-directing agent in a predetermined ratio, the inventors have obtained water under appropriate reaction temperature and reaction time conditions. Although it is a simple manufacturing method that uses thermal synthesis processing, it has a strength that enables machining such as cutting, drilling, and polishing without causing brittle fracture, and it is a relatively large bulk rather than powder or film. It has been found that a zeolite can be produced. Furthermore, in the above production method, not only can a hydrophobic zeolite bulk body be produced by making the alumina source in the reaction solution relatively small, but also an organic template is not blended in the reaction solution. Further, it became clear that a hydrophilic zeolite bulk body can be produced by using a relatively large amount of alumina source, and the present invention has been completed.

That is, the present invention includes the following matters.
[1] It is composed of a zeolite component (A) of 50 to 100 mass% and a silica component (B) of 50 to 0 mass% of α-SiO ₂ and / or amorphous SiO ₂ and has a tensile strength of 3 MPa or more A zeolite bulk body having machinability, characterized by a bending strength of 3 MPa or more.
[2] The zeolite bulk body according to [1], wherein the zeolite component (A) is 60 to 100 mass% and the silica component (B) is 40 to 0 mass%.
[3] The zeolite bulk body according to [1] or [2], wherein the tensile strength is 4 MPa or more or the bending strength is 4 MPa or more.
[4] The zeolite bulk body according to any one of [1] to [3], wherein the volume is 0.05 cm ³ or more.
[5] The zeolite bulk body according to any one of [1] to [4], wherein the zeolite component (A) is hydrophobic with a Si / Al ratio of 3 or more.
[6] The zeolite bulk body according to any one of [1] to [4], wherein the zeolite component (A) is hydrophilic having a Si / Al ratio of 1 or more and less than 3.
[7] Silica source (a), 0.1 to 0.8 mole of alkali metal component (b) as an alkali metal atom equivalent per mole of silica (SiO ₂ ) in the silica source, and alumina ( Al ₂ O ₃ ) containing 0 to 0.05 mol of alumina source (c), 0.02 to 0.15 mol of organic template (d), and 10 to 45 mol of water (e) A reaction solution for hydrothermal synthesis for producing a zeolite bulk body according to [5], wherein
[8] Silica source (a), 0.3 to 3.0 moles of alkali metal component (b) as an alkali metal atom equivalent per mole of silica (SiO ₂ ) in the silica source, and alumina ( Contains 0.05 to 0.7 mol of alumina source (c) in terms of Al ₂ O ₃ ), 0 to 0.1 mol of organic template (d), and 5 to 50 mol of water (e). A reaction solution for hydrothermal synthesis for producing a zeolite bulk body according to [6], wherein
[9] The method for producing a zeolite bulk body according to [5], comprising a step of hydrothermal synthesis treatment of the reaction solution for hydrothermal synthesis according to [7] at a temperature of 175 to 225 ° C.
[10] The production method according to [9], wherein the hydrothermal synthesis treatment time is 1 to 10 days.
[11] The method for producing a zeolite bulk body according to [6], comprising a step of hydrothermal synthesis treatment of the reaction solution for hydrothermal synthesis according to [8] at a temperature of 80 to 200 ° C.
[12] The production method according to [11], wherein the hydrothermal synthesis treatment time is 6 hours to 5 days.
[13] A machined product of a zeolite bulk body according to any one of [1] to [6].
[14] An adsorptive separation agent comprising the zeolite bulk according to any one of [1] to [6] or the machined product thereof according to [13].
[15] A catalyst comprising the bulk zeolite according to any one of [1] to [6] or the machined product thereof according to [13].

The reaction solution of the present invention contains “0 mol of the alumina source (c) as an alumina conversion amount per mol of silica in the silica source” or “0 mol of organic template per mol of silica in the silica source”. “Contains (d)” means that each reaction solution contains substantially no alumina source (c) or organic template (d). That is, in the reaction solution for a hydrophobic zeolite bulk body in which “0” is defined as the lower limit of the content of the alumina source (c), the alumina source (c) is not an essential component but an optional component, and organic In the reaction solution for a hydrophilic zeolite bulk body in which “0” is defined as the lower limit of the content of the template (d), the organic template (d) is not an essential component but an optional component.

According to the present invention, a relatively large zeolite bulk body that can be processed into an arbitrary form by machining can be efficiently manufactured by a simple method using hydrothermal processing. Since the obtained zeolite bulk material does not use any material that impairs the porosity of the zeolite, such as an organic binder, it is expected to have high performance in various applications that utilize characteristics such as the porosity of the zeolite. .

Such a zeolite bulk body can be used as, for example, a membrane support or a catalyst carrier after being formed into an appropriate shape by machining as required. As an example, it can be used as an excellent support for membranous zeolite. In order to utilize the functions of zeolite such as adsorption, molecular sieving, ion exchange, and catalyst to a higher degree, the formation of a membrane has attracted attention. When zeolite is formed into a film, the film itself is not strong enough, so that it is often formed on a support that is a porous body such as alumina, zirconia, and stainless steel. However, cracks and the like are likely to occur due to differences in properties such as thermal expansion between the support and the zeolite membrane, so that the zeolite membrane cannot be used at high temperatures. In addition, since these supports are different from zeolite, their adhesion to the membrane is poor, and there is concern about durability. The components of the support may be dissolved during the production of the membrane, which may adversely affect the original functions of the zeolite such as catalytic action, molecular sieving, and adsorption. On the other hand, since the support formed from the zeolite bulk body of the present invention has properties such as thermal expansion equal to those of the membrane, it can prevent cracks due to differences in expansion. In addition, since the components of the support and the membrane are the same, the components dissolved from the support when synthesizing the membrane on the support are integrated with the support without deteriorating the performance of the zeolite membrane. A heat-resistant zeolite membrane can be produced.

FIG. 1 is a photograph of a zeolite bulk body (left) produced in Example 1 and a machined product (right) thereof. FIG. 2 is an XRD pattern of the zeolite bulk body produced in Example 1. FIG. 3 is an SEM image of a cut surface of the zeolite bulk body produced in Example 1. FIG. 4 is a photograph of the zeolite bulk body produced in Example 2. FIG. 5 is an XRD pattern of the bulk zeolite produced in Example 2. FIG. 6 is a photograph of the product obtained in Reference Example 2. FIG. 7 is an XRD pattern of the product after the heat treatment of Reference Example 2. FIG. 8 is an SEM image of the product after heat treatment of Reference Example 2. FIG. 9 is a schematic diagram of an apparatus for separating and concentrating an aqueous ethanol solution by a vapor permeation method using the bulk machined product produced in Example 1. FIG. 10 is an XRD pattern of the zeolite bulk body produced in Example 4. FIG. 11 is a photograph of a zeolite bulk body (left) and a machined product (right) produced in Example 5. FIG. 12 is an XRD pattern of the zeolite bulk body produced in Example 5. FIG. 13 is a photograph of the powdered zeolite (upper part) and the membranous zeolite (lower part) obtained in Comparative Example 1. FIG. 14 is a photograph of a brittle aggregate of zeolite powder obtained in Comparative Example 2.

-Reaction solution for hydrothermal synthesis-
The reaction solution for hydrothermal synthesis of the present invention contains a silica source, an alkali metal component, water, and, if necessary, an alumina source and an organic template as a structure directing agent in a predetermined ratio. Depending on whether the zeolite component (A) contained in the zeolite bulk body is hydrophobic or hydrophilic, the blending ratio of each component can be adjusted appropriately. Hydrophobic and hydrophilic zeolite bulk bodies are produced by hydrothermal synthesis of reaction solutions for such hydrophobic zeolite bulk bodies and hydrophilic zeolite bulk bodies at synthesis temperatures and synthesis times suitable for each. can do. Hereinafter, (a) a silica source, (b) an alkali metal component, (c) an alumina source, (d) a substance used as an organic template, and an addition amount thereof will be described in detail.

(A) Silica source As the silica source, a commercially available colloidal silica, fumed silica, tetraethyl orthosilicate (TEOS), amorphous silica, amorphous silica, or the like, which is the same as a known zeolite synthesis method, is used. be able to. Each silica source may be prepared by an alkoxide method or may be prepared from water glass (sodium silicate). Properties such as silica concentration, particle diameter and pH are not particularly limited.

(B) Alkali metal component When preparing a reaction solution for a hydrophobic zeolite bulk body, the amount of the alkali metal component in the reaction solution is usually 0. It is adjusted in the range of 1 to 0.8 mol, preferably 0.15 to 0.65 mol, more preferably 0.2 to 0.65 mol.

When preparing a reaction solution for a hydrophilic zeolite bulk body, the amount of the alkali metal component in the reaction solution is usually 0.3 to 3.0 mol as an alkali metal atom conversion amount per mol of silica in the silica source. , Preferably 0.4 to 2.8 mol, more preferably 0.5 to 2.5 mol.

When an alkali metal salt of aluminate (such as sodium aluminate) is used as the aluminum component, the remaining amount of the alkali metal component obtained by subtracting the amount of alkali metal contained therein from the predetermined amount is added as a raw material. That's fine.

As the raw material of the alkali metal component, hydroxides, halides, etc. of alkali metals such as lithium, sodium and potassium can be used as in the known zeolite synthesis methods, but sodium hydroxide is preferred.

(C) Alumina source When preparing a reaction solution for a hydrophobic zeolite bulk body, the amount of alumina source in the reaction solution is usually as alumina (Al ₂ O ₃ ) equivalent per mol of silica in the silica source. It is adjusted in the range of 0 to 0.05 mol, preferably 0 to 0.45 mol, more preferably 0 to 0.04 mol.

When preparing a reaction solution for a hydrophilic zeolite bulk body, the amount of the alumina source in the reaction solution is usually 0.05 to 0 in terms of alumina (Al ₂ O ₃ ) per mole of silica in the silica source. 0.7 mol, preferably 0.07 to 0.6 mol, more preferably 0.1 to 0.5 mol.

When the amount of the aluminum component is larger than the above range, even if a bulk body is obtained, it is not dense but brittle and tends to be inappropriate for machining.

As the alumina source, aluminate or nitrates, sulfates, halides, hydroxides, etc. of alumina can be used as in the known zeolite synthesis methods, but aluminates are preferred. Examples include alkali metal salts such as sodium aluminate, and organic amine salts such as quaternary ammonium aluminate and guanidine aluminate, among which sodium aluminate (NaAlO ₂ ) is particularly preferable. Also, an aluminum acid prepared by dissolving an aluminum compound such as aluminum powder or aluminum hydroxide in an alkaline aqueous solution (for example, an aqueous solution containing a quaternary ammonium aqueous solution such as tetramethylammonium hydroxide aqueous solution or an organic amine such as guanidine or trimethylamine). An aqueous salt solution may be used as a raw material.

(D) Organic template When preparing a reaction solution for a hydrophobic zeolite bulk body, the amount of the organic template in the reaction solution is usually 0.02 to 0.15 mol per mol of silica in the silica source, preferably It is adjusted in the range of 0.03 to 0.13 mol, more preferably 0.04 to 0.12 mol.

When preparing a reaction solution for a hydrophilic zeolite bulk body, the amount of the organic template in the reaction solution is usually 0 to 0.1 mol, preferably 0 to 0.07 mol, per mol of silica in the silica source. More preferably, it is adjusted in the range of 0 to 0.05 mol.

As the organic template, quaternary ammonium salts, crown ethers, alcohols and the like similar to the known zeolite synthesis methods can be used, and among them, quaternary ammonium salts are preferable. Further, among the quaternary ammonium salts, tetraalkylammonium salts are more preferable. For example, tetramethylammonium, tetraethylammonium, tetra-n-propylammonium, tetraisopropylammonium, tetra-n-butylammonium, tetra-n-pentylammonium, triethylmethylammonium, triethyl-n-propylammonium, tri-n-propyl Halides such as methylammonium and tri-n-butylmethylammonium (for example, bromide) and hydroxides can be mentioned. Among them, tetra-n-propylammonium hydroxide (TPAOH) can efficiently synthesize hydrophobic zeolites and the like. Particularly preferred in terms.

(E) Water When preparing a reaction solution for a hydrophobic zeolite bulk body, the amount of water in the reaction solution is usually 10 to 45 mol, preferably 10 to 40 mol, per mol of silica in the silica source. Preferably, it is adjusted in the range of 10 to 35 mol.

When preparing a reaction solution for a hydrophilic zeolite bulk body, the amount of water in the reaction solution is usually 5 to 50 mol, preferably 5 to 47 mol, more preferably 5 to 5 mol per mol of silica in the silica source. It is adjusted in the range of 45 mol.

Regardless of the structure of the zeolite contained in the zeolite component (A), generally, when the amount of water is larger or smaller than the above range, voids are easily formed in the bulk body, and when the amount is particularly large, the bulk body is difficult to obtain.

Ease of formation of the zeolite bulk body may vary depending on the mixing ratio of each component in the reaction solution, but those skilled in the art can prepare a reaction solution that can obtain a zeolite bulk body without undue trial and error. It is possible. For example, a zeolite zeolite may be easily formed by adjusting the amount of water slightly within the above range. The amount of water used in the method for producing a zeolite bulk body of the present invention is significantly smaller than that in the case of synthesizing zeolite powder by a conventional method (about 1/4 to 1/10).

-Production method-
The method for producing a zeolite bulk body according to the present invention comprises hydrothermal synthesis based on conditions suitable for hydrothermal synthesis reaction solutions for hydrophobic zeolite bulk bodies or hydrophilic zeolites containing the above-mentioned specific components. It is characterized by including a process, and an optional process may be further included as necessary. Appropriate conditions for the time and temperature of the hydrothermal synthesis reaction described below can be adjusted by those skilled in the art without undue trial and error.

The reaction solution for hydrothermal synthesis is prepared in advance before the hydrothermal synthesis step. What is necessary is just to put a raw material into a suitable container and to stir and mix for a suitable time so that it may become the predetermined | prescribed compounding composition mentioned above. Usually, the reaction solution for hydrothermal synthesis is prepared as a solution (suspension) in which each raw material is uniformly suspended.

In the hydrothermal synthesis process, the reaction solution is put in a pressure-resistant container (generally, the inner container is an autoclave made of Teflon (registered trademark)) in the heating apparatus, as in the hydrothermal synthesis process in the known zeolite production method. It is performed by heating at a predetermined temperature for a predetermined time. What is necessary is just to heat up in the heating apparatus beforehand to the temperature for a hydrothermal synthesis process. As the pressure vessel, a vessel having a desired size can be used, and a zeolite bulk body corresponding to the size of the pressure vessel (for example, a truncated cone shape having a bottom diameter of 1 cm or more) is obtained. The zeolite bulk is usually generated at the bottom of the pressure vessel.

When using a reaction solution for a hydrophobic zeolite bulk body, the treatment time of the hydrothermal synthesis step is preferably 1 to 10 days, and more preferably 3 to 8 days. When using a reaction solution for a hydrophilic zeolite bulk body, the treatment time in the hydrothermal synthesis step is preferably 6 hours to 5 days, more preferably 12 hours to 4 days. If the treatment time is shorter than the above range, it is difficult to obtain a zeolite bulk body (becomes a powder or amorphous bulk body), and if necessary, the organic template (d) inside the amorphous body is also subjected to heat treatment performed after this step. May be carbonized without being removed. On the other hand, if the treatment time is long, a bulk material containing more zeolites (for example, analcime: structure code ANA) of other structures than the target zeolite (for example, ZSM-5: structure code MFI and mordenite: structure code MOR) There is a case.

When using a reaction solution for a hydrophobic zeolite bulk body, the treatment temperature in the hydrothermal synthesis step is preferably adjusted in the range of 175 to 225 ° C., more preferably 190 to 210 ° C. When the reaction solution for the hydrophilic zeolite bulk is used, the treatment temperature in the hydrothermal synthesis step is preferably adjusted in the range of 80 to 200 ° C, more preferably 80 to 180 ° C. If the treatment temperature is lower than the above range, it is difficult to obtain a bulk material. Conversely, if the treatment temperature is high, a bulk material containing a large amount of zeolite having a structure other than the target zeolite may be obtained.

After the hydrothermal synthesis step, a water washing step for removing alkali and a heat treatment step for removing the organic template are further performed as necessary. These steps may be performed in the same manner as the steps in a known zeolite production method.

-Zeolite bulk-
The zeolite bulk body of the present invention has machinability and is typically obtained by the above-described method for producing a zeolite bulk body of the present invention.

The zeolite bulk body is mainly composed of the zeolite component (A). The amount of the zeolite component (A) in the zeolite bulk body (when the component includes zeolite having a plurality of structures, the total amount thereof) is usually 50 to 100 mass%, preferably 60 to 100 mass%, more preferably 75-100 mass%.

Further, the zeolite bulk body may contain a silica component (B) composed of α-SiO ₂ (crystal) and / or amorphous SiO ₂ in addition to the zeolite component (A). The amount of silica component (B) in the zeolite bulk body (when the component includes both α-SiO ₂ and amorphous SiO ₂ ) is usually 50 to 0 mass%, preferably 40 to 0 mass% More preferably, it is 25 to 0 mass%.

As long as there is practically no problem in the use of the zeolite bulk body or its machined product, components other than the components (A) and (B) derived from the raw materials described above remain in the zeolite bulk body to some extent. It is also acceptable.

Zeolite bulk has strength that allows machining without causing brittle fracture. For example, if the “tensile strength” measured according to JIS M 0303: 2000 (Tensile strength test method of rock) is used as an index, the tensile strength of the zeolite bulk body is usually 3 MPa or more, preferably 4 MPa or more. is there. In addition, if “bending strength” measured according to JIS R 1601: 2008 (method for testing room temperature bending strength of fine ceramics) is used as an index, the bending strength of the zeolite bulk body is usually 3 MPa or more, preferably 4 MPa. That's it.

The size of the bulk zeolite is not particularly limited as long as it can be distinguished from the conventional zeolite in the form of at least a fine powder or a thin film. The size of the zeolite bulk body is typically may vary depending on the size of the container used in the manufacturing method of the zeolite bulk body of the present invention described above, preferably 0.05 cm ³ or more, more preferably 0.1 cm ³ or more, More preferably, it is 0.5 cm ³ or more.

Depending on the conditions of the reaction solution and the production method, the obtained bulk zeolite may not be solid, and some voids may be formed inside, but the required strength and performance can be ensured depending on the application. It is acceptable if it is within range.

The zeolite bulk body can be either hydrophobic or hydrophilic depending on the crystal structure of the zeolite contained in the zeolite component (A). The terms hydrophobic and hydrophilic are relative expressions, but in the present invention, the zeolite bulk is “hydrophobic” when the Si / Al ratio of the zeolite component (A) is 3 or more. The zeolite bulk body is “hydrophilic” when the Si / Al ratio of the zeolite component (A) is 1 or more and less than 3 (usually, the Si / Al ratio of the zeolite is less than 1). Never). The Si / Al ratio of the obtained zeolite bulk can be determined by a general method (fluorescence X-ray analysis, ICP emission analysis, etc.).

Table 1 shows typical zeolites. Representative examples of hydrophobic zeolite include MFI (ZSM-5), MOR (mordenite) and the like, while representative examples of hydrophilic zeolite include LTA (A type), FAU (X type or Y type). ), CAN (cancrinite), and the like, but the crystal structure contained in the bulk zeolite of the present invention is not limited to both hydrophobic and hydrophilic. The crystal structure of zeolite may be occupied by only one kind, or may be occupied by two or more kinds.

The crystal structure of the zeolite bulk body can be adjusted by the treatment time and treatment temperature of the hydrothermal synthesis step in the production method described above.

The contents of the zeolite component (A) and the silica component (B) in the zeolite bulk body can be quantified from the X-ray diffraction (XRD) pattern of the crystal structure of the zeolite bulk body according to a conventional method.

-Applications-
The zeolite bulk body of the present invention has a molecular sieving ability, adsorption ability, ion exchange ability, solid acidity, etc., as in the case of conventional powdery or membrane-like zeolites and molded articles produced by adding a binder to them. It can be used for various applications utilizing the characteristics of zeolite.

The use of the zeolite bulk material is not particularly limited, but as one of the typical applications, a liquid in which various molecules are mixed depending on properties such as the atoms constituting the zeolite and the size of the zeolite pores. Alternatively, it can be used as a separation / adsorption material for separating or adsorbing specific molecules from gas.

For example, hydrophobic zeolite can be used as a separator for organic substances such as alcohol. General bioethanol is recovered as an aqueous ethanol solution with a concentration of about 5 to 10 mass%. By using hydrophobic zeolite, ethanol is allowed to pass through the zeolite pores while keeping the water molecules away from the zeolite pores. The aqueous ethanol solution can be concentrated. By repeating the concentration operation about 2 to 3 times, the ethanol concentration is increased to about 99 mass% that can be used as bioethanol fuel much more efficiently (with low energy) than known methods such as distillation. be able to.

On the other hand, since hydrophilic zeolite can adsorb water mixed in liquid or gas to the zeolite pores, it can be used as a dehydrating / drying material.

Zeolite can be used as a catalyst for various reactions. For example, for the purpose of improving the octane number of gasoline, a reaction in which a long-chain alkane is shortened (catalytic decomposition) or a linear alkane is branched (catalytic reforming) is widely performed. As a catalyst for these reactions, a zeolitic catalyst (for example, zeolite carrying Pt) or the like can be used. A zeolite-based catalyst can also be used for the isomerization of xylene obtained by converting p-xylene from other isomers (such as ethylbenzene and m-xylene). Among zeolites, ZSM-5, in particular, has a pore size just as large as that of the target p-xylene, and therefore can selectively generate p-xylene while suppressing disproportionation.

The zeolite bulk body can be processed into an arbitrary shape by machining such as cutting, drilling, and polishing depending on the application. For example, it can be machined into a tube having openings at both ends or one end for applications such as separation of mixed solutions and gas separation. It can also be machined into a disk shape for applications such as membrane zeolite supports.

[Example 1]
Colloidal silica (formula 60.09, purity 40%, balance is water, Nissan Chemical Industries), sodium hydroxide (formula 40.00, purity 96%, Nacalai Tesque), sodium aluminate (formula 81.97, Purity 69.5%, Kanto Chemical), TPAOH (formula weight 203.36, 1M in H ₂ O, ALDRICH) and ultrapure water, SiO ₂ : 0.3NaOH: 0.016Al ₂ O ₃ : 0.066TPAOH: 22.5H ₂ The mixture was mixed at a composition ratio of O and stirred with a stirrer for 24 hours to obtain a reaction solution. 20 ml of this reaction solution was put into a Teflon container having a volume of 30 ml, and this container was put into a heating apparatus heated in advance to 200 ° C., and hydrothermal synthesis was performed at a synthesis temperature of 200 ° C. for 5 days. Then, in order to remove an alkali content, it wash | cleaned by the ultrasonic treatment for 2 hours with the pure water, and in order to remove organic substance, it heat-processed at 600 degreeC for 5 hours. The mass of the obtained bulk body was 1.98 g, and the density was 2.1 g / cm ² . Further, ZSM-5 in the bulk material, α-SiO _{_2,} SiO ₂ content of amorphous, using a commercially available ZSM-5 powder and alpha-SiO _2, Si, a calibration curve is prepared by XRD, quantitative It was done. As a result, ZSM-5: 78mass%, α-SiO 2: 12mass%, amorphous SiO _2: was 10 mass%. The Si / Al ratio was estimated to be about 25 by XRD and fluorescent X-ray. In addition, Rigaku RINT2100 / PC (CuKα ray, θ-2θ, timed measurement method) was used for XRD, and Rigaku ZSX Primus II-R1 was used for fluorescent X-ray. The photograph of the bulk body obtained in FIG. 1 (left) is shown.

Further, after the bulk body obtained in the above example was cut into a disk shape (diameter 13 mm, thickness 7 mm), it was drilled with an electric drill (manufactured by Ryobi) with a carbon steel drill (diameter 8 mm). I made a hole. Fig. 1 (right) shows a photograph of this machined product.

This bulk was identified as ZSM-5 (structure code: MFI), which is a more hydrophobic zeolite than XRD. FIG. 2 shows an XRD pattern of the bulk body, and FIG. 3 shows an SEM image of the bulk body.

In addition, the tensile strength of the bulk body was measured in accordance with JIS M 0303 (Method of testing tensile strength of rocks). For the measurement, “Autograph DCS-R-10TS” (Shimadzu Corporation) was used, and the crosshead speed was 0.5 mm / min. As a result, the tensile strength was 4 MPa.

Next, the bending strength of the bulk body was measured according to JIS R 1601 (room temperature bending strength test method for fine ceramics). “Autograph EZ-Test” (Shimadzu Corporation) was used for the measurement, and the crosshead speed was 0.5 mm / min. As a result, the bending strength was 5 MPa.

[Example 2]
200 ml of the same reaction solution as in Example 1 was placed in a 350 ml Teflon container, hydrothermally synthesized at 240 ° C. for 1 hour, and then hydrothermally synthesized at 200 ° C. for 5 days. FIG. 4 shows a photograph of the obtained bulk body, and FIG. 5 shows an XRD pattern. The composition of the obtained bulk body, the quantitative analysis by XRD, ZSM-5: 83mass% , α-SiO 2: 7mass%, amorphous SiO _2: was 10 mass%.

[Reference Example 1]
About Example 1, when the composition ratio of H ₂ O in the reaction solution was changed from 22.5 to 100, 50, 10, the bulk body was not generated in the case of 100, but the bulk body was generated in the case of 50. There were large pores, and in the case of 10, a bulk body was formed but there were many voids.

[Reference Example 2]
Example 1 was treated in the same manner except that the hydrothermal synthesis temperature was changed to 190 ° C. and the time was changed to one of 1, 3 hours, 12 hours, 24 hours, 3 days, 7 days, and 9 days. .

FIG. 6 shows photographs of the products (after hydrothermal synthesis and after heat treatment) obtained by each treatment. FIG. 7 shows the XRD of the product after each heat treatment. In FIG. 8, the SEM image of the product after each heat processing is shown.

When the hydrothermal synthesis time was 1 hour, bulk zeolite was not obtained. In the case of 3 hours and 12 hours, the product after hydrothermal synthesis is an amorphous translucent bulk body, and the organic matter inside the amorphous body is carbonized without being sufficiently removed by heat treatment, resulting in blackening. Destroyed. In the case of 24 hours and after 3 days, a white bulk body was formed. From the XRD pattern, peaks other than ZSM-5 could not be observed. In the case of 7 days, a zeolite bulk body containing α-SiO ₂ was obtained, and the crystals grew larger. In the case of 9 days, the obtained bulk body contained analthyme, ZSM-5 and α-SiO ₂ .

[Example 3]
The bulk body produced in Example 1 was processed into a diameter of 10 mm and a thickness of 3 mm, and an ethanol aqueous solution concentration experiment was performed using the vapor permeation method (see FIG. 9). 200 ml of an ethanol aqueous solution of 5 mass%, 50 mass%, 70 mass%, and 90 mass% was heated to 40 ° C. and sucked with a vacuum pump for 30 minutes. The permeated solution was aggregated with a cold trap, and the ethanol concentration in the aggregate was measured with a gas chromatograph (Shimadzu Corporation, GC14A) equipped with FID. Table 2 shows the results. In the 5 mass% ethanol aqueous solution, 2.7 g of an ethanol aqueous solution having a concentration of about 70 mass% permeated. In a 50 mass% ethanol aqueous solution, 5.7 g of an ethanol aqueous solution having a concentration of about 89 mass% permeated. In the 70 mass% ethanol aqueous solution, 7.1 g of an ethanol aqueous solution having a concentration of about 93 mass% permeated. In the 90 mass% ethanol aqueous solution, 8.2 g of ethanol aqueous solution having a concentration of 99 mass% or more permeated.

[Example 4]
Sodium hydroxide (formula 40.00, purity 96%, Nacalai Tesque), sodium aluminate (formula 81.97, purity 69.5%, Kanto Chemical), TPAOH (formula 203.36, 1M in H ₂ O, ALDRICH) and ultrapure water were mixed at a composition ratio of SiO ₂ : 0.55NaOH: 0.025Al ₂ O ₃ : 0.09TPAOH: 27.3H ₂ O and stirred with a stirrer for 24 hours to obtain a reaction solution. Thereafter, 20 ml was placed in a 30 ml Teflon container, and hydrothermal synthesis was performed at a synthesis temperature of 200 ° C. for 5 days. Then, in order to remove an alkali content, it wash | cleaned by the ultrasonic treatment for 2 hours with the pure water, and in order to remove organic substance, it heat-processed at 600 degreeC for 5 hours.

The obtained bulk material was identified by XRD as mordenite (Si / Al = 5, structure code: MOR), which is a hydrophobic zeolite. FIG. 10 shows the XRD pattern of the bulk body. .

[Example 5]
Colloidal silica (formula 60.09, purity 40%, balance is water, Nissan Chemical Industries), sodium hydroxide (formula 40.00, purity 96%, Nacalai Tesque), sodium aluminate (formula 81.97, (Purity 69.5%, Kanto Chemical) and ultrapure water were mixed at a composition ratio of SiO ₂ : 1.3NaOH: 0.2Al ₂ O ₃ : 7.8H ₂ O and stirred for 24 hours with a stirrer. After preparing the solution, 20 ml was put into a 30 ml Teflon container, and hydrothermal synthesis was performed at a synthesis temperature of 185 ° C. for 2 days. Then, in order to remove alkali content, it wash | cleaned by the ultrasonic treatment for 2 hours with the pure water. As a result, a bulk body was formed in the full Teflon container, and there was no conspicuous void even when the cut surface was seen. The photograph of the bulk body obtained in FIG. 11 (left) is shown.

Further, after the bulk body obtained in the above example was cut into a cylindrical shape (diameter: 18 mm, thickness: 13 mm), it was drilled with an electric drill (manufactured by Ryobi) with a carbon steel work drill (diameter 8 mm). I made a hole. FIG. 11 (right) shows a photograph of this machined product.

The obtained bulk body was identified as cancrinite (Si / Al = 1, structure code: CAN), which is a more hydrophilic zeolite than XRD. The composition of the obtained bulk body, the quantitative analysis by XRD, _{cancrinite: 85mass%, α-SiO 2} : 0mass%, amorphous SiO _2: was 15 mass%. FIG. 12 shows the XRD pattern of the bulk body. Further, the bending strength in accordance with JIS R 1601 (room temperature bending strength test method for fine ceramics) was measured under the same conditions as in Example 1. As a result, the bending strength was 4 MPa.

[Comparative Example 1]
A follow-up experiment of Example 11 of Patent Document 6 (Japanese Patent Laid-Open No. 7-89716) was conducted. That is, composition of SiO ₂ / Al ₂ O ₃ = 20.0, crystallization agent / SiO ₂ = 0.08 (crystallization agent = tetrapropylammonium bromide), Na ₂ O / SiO ₂ = 0.296, H ₂ O / SiO ₂ = 20.0 In the hydrothermal synthesis using this, the temperature was raised to 180 ° C. at a constant rate of 2 ° C./min and held at that temperature for 36 hours. As a result, the obtained zeolite was identified as a mixture of mordenite and Na-P zeolite and was not ZSM-5. Moreover, a zeolite bulk body that can be machined is not obtained, and a powdery zeolite (upper part of FIG. 13) and a thin film of zeolite particles (lower part of FIG. 13) are obtained in a Teflon reaction vessel. It was. The obtained zeolite membrane was far from a dense membrane and was brittle with many holes in the surface. The follow-up experiment was performed twice, but the results were the same for both.

[Comparative Example 2]
A follow-up experiment of Comparative Example 2 of Patent Document 6 (Japanese Patent Laid-Open No. 7-89716) was conducted. That is, SiO ₂ / Al ₂ O ₃ = 10.0, crystallization agent / SiO ₂ = 0.20 (crystallization agent = tetrapropylammonium bromide), Na ₂ O / SiO ₂ = 0.373, H ₂ O / SiO ₂ = 20.0 In the hydrothermal synthesis using this, the temperature was raised to 180 ° C. at a constant rate of 2 ° C./min and held at that temperature for 36 hours. As a result, a blocky zeolite was obtained at the bottom of the Teflon reaction vessel, which was identified as an anthracite and not ZSM-5. However, when it was taken out, it collapsed easily as shown in FIG. In other words, this lump was a brittle aggregate of powder that lightly hardened snow by hand. The follow-up experiment was performed twice, but the results were the same for both.

Claims

It is composed of a zeolite component (A) of 50 to 100 mass% and a silica component (B) of 50 to 0 mass% of α-SiO 2 and / or amorphous SiO 2 , and has a tensile strength of 3 MPa or more or a bending strength. A zeolite bulk body having machinability, which is 3 MPa or more.
The zeolite bulk body according to claim 1, wherein the zeolite component (A) is 60 to 100 mass% and the silica component (B) is 40 to 0 mass%.
The zeolite bulk body according to claim 1 or 2, wherein the tensile strength is 4 MPa or more or the bending strength is 4 MPa or more.
The zeolite bulk body according to any one of claims 1 to 3, having a volume of 0.05 cm 3 or more.
The zeolite bulk body according to any one of claims 1 to 4, wherein the zeolite component (A) is hydrophobic having a Si / Al ratio of 3 or more.
The zeolite bulk body according to any one of claims 1 to 4, wherein the zeolite component (A) is hydrophilic having a Si / Al ratio of 1 or more and less than 3.
The silica source (a), 0.1 to 0.8 mole of alkali metal component (b) as an alkali metal atom equivalent per mole of silica (SiO 2 ) in the silica source, respectively, and alumina (Al 2 O 3 ) As an equivalent amount, 0 to 0.05 mol of alumina source (c), 0.02 to 0.15 mol of organic template (d), and 10 to 45 mol of water (e) are contained. A reaction solution for hydrothermal synthesis for producing a zeolite bulk body according to claim 5, characterized in that it is characterized in that
A silica source (a), 0.3 to 3.0 moles of an alkali metal component (b) as an alkali metal atom equivalent per mole of silica (SiO 2 ) in the silica source, respectively, and alumina (Al 2 O 3 ) It contains 0.05 to 0.7 mol of alumina source (c), 0 to 0.1 mol of organic template (d), and 5 to 50 mol of water (e) as converted amounts. The reaction solution for hydrothermal synthesis for producing a zeolite bulk body according to claim 6, characterized in that it is characterized in that
The method for producing a zeolite bulk body according to claim 5, comprising a step of hydrothermal synthesis treatment of the reaction solution for hydrothermal synthesis according to claim 7 at a temperature of 175 to 225 ° C.
The production method according to claim 9, wherein the hydrothermal synthesis treatment time is 1 to 10 days.
The method for producing a zeolite bulk body according to claim 6, comprising a step of hydrothermal synthesis treatment of the reaction solution for hydrothermal synthesis according to claim 8 at a temperature of 80 to 200 ° C.
The production method according to claim 11, wherein the hydrothermal synthesis treatment time is 6 hours to 5 days.
A machined product of a zeolite bulk body according to any one of claims 1 to 6.
An adsorption / separation agent comprising the zeolite bulk according to any one of claims 1 to 6 or the machined product thereof according to claim 13.
A catalyst comprising the zeolite bulk according to any one of claims 1 to 6 or the machined product thereof according to claim 13.