JP2001139323A - Nu-1 type binderless zeolite molding and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a binderless zeolite molding substantially consisting of NU-1 type zeolite alone. SOLUTION: The zeolite precursor expressed by the formula Si1(TMA)xM1yM2z (where, TMA denotes tetramethyl ammonium; M1 denotes an alkaline metal; M2 denotes the metal element to be incorporated into a metallosilicate crystal skeleton; (x) denotes a range of 0.01 to 1; (y) 0.0001 to 1; and (z) 0 to 0.3) is brought into contact with saturated steam of 80 to 260 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a NU-1 type binderless zeolite molded product and a method for producing a NU-1 type binderless zeolite molded product. The NU-1 type zeolite means a "RUT type" zeolite which is described by a code indicating a structure according to the International Zeolite Society.

[0002]

2. Description of the Related Art NU-1 type zeolite is a zeolite first discovered in 1977 as an aluminosilicate having small pores of a six-membered oxygen ring, and its structure can be identified by powder X-ray diffraction. The crystalline aluminosilicate composed of silicon and aluminum as a metal component (hereinafter sometimes referred to as T atom) constituting the zeolite crystal skeleton is mainly composed of Al ³⁺ in a crystal lattice for the purpose of controlling its acidity.
It is widely practiced to replace cations with other metal ions, and in general, NU-1 type including aluminum-free silicalite having the same structure and crystalline metallosilicate in which aluminum is replaced by other metal ions. It is called zeolite. As the NU-1 type crystalline metallosilicate, a zeolite containing boron, gallium, iron, titanium, and the like in a T atom is known.

As a method of synthesizing these NU-1 type zeolites, a so-called hydrothermal synthesis method using an aqueous reaction slurry using a tetramethylammonium salt as a template agent as a raw material is conventionally known.

[0004] However, in the conventional hydrothermal reaction method, a part of the raw material components are dissolved in water at the time of heating, so that the ratio of the components converted into crystals is inevitably reduced, so that the yield is low. In addition, according to such a crystallization method in which an alkali component is diluted, large crystals are easily grown, and silicon (S
Since foreign metal components (M) other than i) are easily excluded outside the crystal lattice, the atomic ratio of Si / M (M represents T atom other than silicon) in the aqueous slurry and the synthesized NU
The atomic ratio of Si / M in the type-1 zeolite does not always match. Further, industrially, it is necessary to use a closed container having a relatively large volume with respect to the weight of generated crystals in order to heat an aqueous slurry, to use a large amount of an expensive template agent, and to use a large amount of waste liquid. , The zeolite powder is filtered, and the firing step is complicated.

[0005] Further, when a conventional zeolite molded body is manufactured, it is necessary to first synthesize a zeolite powder by a hydrothermal synthesis method and then mold it using an inorganic binder, because the moldability of zeolite alone is poor. there were. In this method, it is necessary to select a binder that does not adversely affect the intended use, and not only does the zeolite content in the molded body decrease because a large amount of inorganic binder is required to obtain sufficient strength. There is a problem that zeolite buried in the binder cannot be used effectively. A method of manufacturing a supported zeolite molded article using an inorganic molded article has also been proposed. For example, JP-A-11-
In the specification of Japanese Patent No. 165074, an aqueous gel composed of tetraethyl orthosilicate, tetraethyl orthotitanate and tetrapropylammonium hydroxide is supported on a silica carrier, and then subjected to MF treatment by steaming under pressure.
Form I crystalline titanosilicate is crystallized on the support. In this method, it is necessary to use a low-concentration aqueous gel having sufficient fluidity to be able to be supported on the carrier. That is, the supported zeolite molded article obtained by this method has a problem that the zeolite content is extremely low.

Therefore, several methods for producing a zeolite molded article substantially containing no binder have been proposed. For example, Japanese Patent Application Laid-Open No. 59-162952 (TSZ-type aluminosilicate) and Japanese Patent Application Laid-Open No. 61-72620 (MOR) Type aluminosilicate) and JP-A-62-138320 (F
Some limited types of crystal-type binderless aluminosilicate moldings, such as AU-type aluminosilicate), are known. However, binderless NU-1 type aluminosilicate molded articles have not been known at all.

In these methods, a zeolite powder synthesized in advance is used as a secondary raw material, and this is molded with an inorganic binder such as a clay mineral or silica-alumina sol and reacted with an alkaline solution to form a binder. Requires substantially twice hydrothermal synthesis. For this reason, there is a problem in that the process becomes longer and the amount of waste liquid increases.

Further, a method of synthesizing a binderless silicalite molded article in which the metal component constituting the crystal skeleton is substantially composed of only silicon or a binderless crystalline metallosilicate molded article composed of T atoms other than aluminum. Was not known.

As described above, a NU-1 type binderless zeolite molded article substantially containing no binder and a simple and efficient production method thereof have not been known.

[0010]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a NU-1 type binder consisting essentially of zeolite crystals without containing an inorganic binder. An object of the present invention is to provide a reseolite molded body.

Another object of the present invention is to provide a simple and efficient method for producing a NU-1 type zeolite molded body without using a binder.

[0012]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on a NU-1 type binderless zeolite molded product, and have found that, for example, a tetramethylammonium component, an alkali metal component and another metal component are combined with a silica molded product. After being supported, the entire amount of silica is crystallized while maintaining the shape of the silica molded body by a method of contacting with saturated steam under specific conditions, and at the same time, the binder essentially taking in the metal component as a T atom is removed. It has been found that a NU-1 type binderless zeolite molded body containing no NU-1 can be easily produced with high yield, and the present invention has been completed.

That is, the present invention relates to a binderless zeolite molded body, wherein the zeolite has a NU-1 type crystal structure.

The binderless zeolite molded body is
For example, the specific surface area determined from nitrogen adsorption measurements by BET method, which is binderless zeolite molded body is 20m ² / g~200m ² / g.

According to another aspect of the present invention, the following formula (1): Si ₁ (TMA) _x M ¹ _y M ² _z (1) (wherein TMA is tetramethylammonium, M ¹ is an alkali metal, M ² represents a metal element incorporated in the metallosilicate crystal skeleton, x is 0.01 to 1, and y is 0.0
001 to 1 and z represent a range of 0 to 0.3. The present invention relates to a method for producing a binderless zeolite molded body, which comprises contacting the zeolite precursor represented by the formula (1) with saturated steam at 80 to 260 ° C.

The zeolite precursor may be a zeolite precursor obtained by supporting a raw material containing a tetramethylammonium component, an alkali metal component, and a metal component incorporated in a metallosilicate crystal skeleton on a silica molded body. It is preferred.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below.

The zeolite precursor used in the method for producing a binderless zeolite molded article of the present invention is represented by the following formula (1): Si ₁ (TMA) _x M ¹ _y M ² _z (1) Represents tetramethylammonium, M ¹ represents an alkali metal, M ² represents a metal element incorporated in the metallosilicate crystal skeleton, x is 0.01 to 1, and y is 0.0
001 to 1 and z represent a range of 0 to 0.3. ) Is not particularly limited. Equation (1)
In the formula, M ¹ represents an alkali metal such as lithium, sodium, or potassium, and M ² is a metal element incorporated into the metallosilicate crystal skeleton, for example, boron, aluminum,
Represents at least one element selected from the group consisting of titanium, iron, zinc, gallium and indium. Further, in the above formula (1), x is 0.02 to 1, and y is 0.0
It is preferable that 001 and z have a composition in the range of 0 to 0.25, and in the above formula (1), x is 0.0
4-0.8, y is 0.0002-0.5, z is 0-0.
More preferably, the composition is in the range of 2.

The method for preparing the zeolite precursor is not particularly limited, but a raw material containing a tetramethylammonium component, an alkali metal component, and, if desired, at least one metal component incorporated in a metallosilicate crystal skeleton to be supported. A method of supporting a substance on a silica molded body is preferable.

When the tetraalkylammonium component and the alkali metal component are supported on the silica molded body, a binderless NU-
A type 1 silicalite molded article can be produced, and in addition to the two components, at least one selected from the group consisting of boron, aluminum, titanium, chromium, iron, cobalt, nickel, copper, zinc, gallium and indium When the metal component (1) is carried, a NU-1 type binderless crystalline metallosilicate molded body in which this is incorporated as a T atom can be produced.

The silica molded body is not particularly limited, and a commercial product can be used. Silica molded body used suitably is relatively large molded specific surface area, specific surface area determined from nitrogen adsorption measurements by conventional BET method, for example, 5m ² / g~1000m ² / g, preferably 20 m ² / g to An object in the range of 800 m ² / g is used. If the specific surface area is too small, crystallization requires a long time, and the degree of crystallization may be deteriorated.

The silica molded body has pores having a pore diameter of 4 nm or more, for example, determined by a mercury intrusion method, and the surface area and the pore volume of the pores are each 5 m ² / g to 5 m ² / g.
1000 m ^{2 /} g, 0.10 ml / g to 1.5 ml / g
, And the preferably ^{20m 2 / g~800m 2 / g,} 0.
The range is from 15 ml / g to 1.3 ml / g.

Examples of the tetramethylammonium component include tetramethylammonium halides and hydroxides, and tetramethylammonium hydroxide is preferably used. By using tetramethylammonium hydroxide,
NU-1 type zeolite can be efficiently synthesized.

As the alkali metal component, lithium,
Examples thereof include sodium and potassium, and hydroxides, halides or silica carriers thereof and / or
Alternatively, an alkali metal component in a metal salt compound can be used.

When synthesizing a NU-1 type binderless crystalline metallosilicate molded product, a salt of a metal to be a T atom is supported on a silica carrier together with the tetramethylammonium component and the alkali metal component. . These metal salts include boron, aluminum, titanium,
Nitrates, sulfates, halides such as chromium, iron, cobalt, nickel, copper, zinc, gallium, indium,
Examples thereof include oxo acid salts and hydroxides, and these are preferably used in the form of an aqueous solution. When the metal salt is a metal salt of at least one metal selected from the group consisting of boron, aluminum, iron and gallium, a high crystallinity is preferably obtained.
These metal components are converted into binderless metallosilicate by being incorporated into the zeolite framework during crystallization.

The method for supporting a raw material containing a tetramethylammonium component, an alkali metal component, and one or more metal components incorporated into a metallosilicate crystal skeleton to be supported as required on the silica molded body is not particularly limited. However, since it is desirable that the raw material is uniformly supported in the silica molded body, it is usually dried by impregnating with an aqueous solution. As an example, a predetermined amount of each component is made into a uniform aqueous solution, which is prepared and impregnated so as to have an aqueous solution amount corresponding to the water absorption amount of the silica molded body. At this time, each component may be supported at the same time, or each component or a uniform mixed solution may be supported by dividing it into several times. Has no effect on

The drying temperature after the impregnation with the aqueous solution is not particularly limited, but is preferably 20 ° C. to 150 ° C., and more preferably 50 ° C., in that the decomposition of the tetramethylammonium salt is small, and the water content is suppressed efficiently. C. to 120.degree. As for the water content of the precursor, 30% or less, in that the supported component is not eluted during crystallization and the yield is good,
Further, the range is preferably 20% to 0.1%.

The drying method is not particularly limited, and the drying can be performed under reduced pressure or normal pressure. Drying under an air stream at normal pressure is preferred because it is simple.

The method of the present invention is characterized in that the zeolite precursor is brought into contact with saturated steam.

The temperature of the saturated steam is not particularly limited, and the crystallization rate is high, the decomposition of the contained tetramethylammonium component is small, and a NU-1 type binderless zeolite molded article having a high crystallinity can be obtained. , 80-2
A range of 60 ° C is preferable, and 100 ° C to 240 ° C is more preferable.

The contact time with the saturated steam is not particularly limited, but is usually 5 to 300 hours, preferably 12 to 200 hours.
Time range. If the crystallization time is too short, the degree of crystallinity will decrease, and if it is too long, a mixed crystal with other minerals may be formed.

The method and apparatus for heating the zeolite precursor by bringing it into contact with saturated steam are not particularly limited. For example, it can be carried out by installing a precursor in the hollow of a pressure-resistant container, enclosing water corresponding to a saturated steam amount determined by a reaction temperature and a volume of the container in a lower portion of the container, and then heating in a constant temperature bath. Embodiments are not limited to this. This precursor may be placed in a vessel and a sealed vessel containing water outside may be used, or the precursor is continuously synthesized by a fixed-bed reactor or a moving-bed reactor in contact with saturated steam. You can also.

By using the production method of the present invention, crystallization can be carried out by contacting the zeolite precursor with saturated steam without dispersing the zeolite precursor in water and causing a hydrothermal reaction. If desired, the supported metal component can be converted to a NU-1 type zeolite having T atoms. As a result, the whole amount of the silica molded body as a raw material is converted into zeolite while maintaining its shape, so that the generated zeolite contains essentially no binder, and a NU-1 type binderless zeolite molded body can be easily produced. It is inferred.

Since no binder is used in the production method of the present invention, the NU-1 type zeolite molded product synthesized by the production method of the present invention has a zeolite content of almost 100%.
Has a very high crystallinity. By selecting an appropriate precursor composition ratio, crystallization temperature and crystallization time from the above conditions, the crystallinity of the molded article can be controlled, for example, 95% or more, preferably 98% or more. . The crushing strength can be controlled by the crystallinity.

In the production method of the present invention, the silica molded body is molded into an arbitrary shape such as a sphere, a cylinder or a ring by a conventional method, and then converted into a zeolite by the method of the invention to obtain a sphere or a cylinder. A binderless zeolite molded article having an arbitrary shape such as a mold and a ring mold can be manufactured. Since the silica carrier itself as the raw material is converted into the zeolite as it is, a binderless zeolite molded body which maintains the shape of the silica molded body can be obtained.

In the production method of the present invention, not only the appearance of the raw material silica molded body is maintained, but also the crushing strength, the distribution of macropores, and the like are reflected. For this reason, by controlling the physical properties of the silica molded body used as a raw material in a conventional manner, the physical properties of the binderless zeolite molded body can be easily controlled.

Further, the binderless zeolite molded article of the present invention is characterized in that (1) the zeolite has a RUT type crystal structure, and (2) the composition ratio (atomic ratio) between silicon and the metal constituting the zeolite crystal structure is as follows. , Silicon, and the metal is in a range of 0 to 0.3.

The zeolite in the molded article of the present invention is RUT
It has a type crystal structure. This is based on the powder X-ray diffraction spectrum of the obtained zeolite, for example, from the literature (Zeolite).
s18, p. 361 (1997)).

In the structure of the RUT-type zeolite, a TO ₄ tetrahedron in which four oxygen atoms are coordinated at the apexes with the T atom at the center forms a zeolite crystal skeleton by three-dimensionally bonding. For this reason, silicalite in which T atoms consist only of silicon is electrically neutral and does not exhibit solid acidity. Replacing Si ⁴⁺ with another valence metal gives TO
It is well known that cations such as protons exist in the crystal to electrically neutralize the ₄ anions, which causes solid acidity to develop. These cations can be easily exchanged by ordinary operations. Also, T
The amount and type of acid of the solid acidic acid to be developed can be controlled by the amount and type of the element introduced as an atom. The solid acidity can be evaluated by a thermal desorption (TPD) method of ammonia or the like.

In the molded article of the present invention, the composition ratio (atomic ratio) of the metal component constituting the zeolite crystal structure in the molded article is as follows:
In the range of 0 to 0.3, preferably 0.0
005 to 0.2.

The molded article of the present invention has a specific surface area of, for example, 20 m ² / g determined by nitrogen adsorption measurement by the BET method.
２００200 m ² / g, preferably 30 m ² / g〜18
It is in the range of 0 m ² / g.

The molded article of the present invention has, for example, secondary pores having a pore diameter of 4 nm or more determined by a mercury intrusion method,
The surface area and pore volume of the pores are 2 m ² / g, respectively.
１５０150 m ^{2 /} g, 0.10 ml / g to 1.5 ml / g
, And the preferably 3m ² / g~100m ² /g,0.1
The range is from 3 ml / g to 1.3 ml / g.

The molded article of the present invention can be easily and efficiently produced by the above-mentioned method for producing a binderless zeolite molded article.

Examples of the shape of the molded article of the present invention include a sphere, a cylinder and a ring.
There is no particular limitation.

Since the molded article of the present invention can easily control the shape, size, macropore distribution, and the like, it can be used as an adsorbent, a catalyst for a chemical reaction, or a catalyst carrier in various chemical processes. , An alkylation reaction catalyst,
It is preferably used as an isomerization reaction catalyst, a transesterification reaction catalyst, a cracking reaction catalyst, a Beckmann rearrangement reaction catalyst, a hydration reaction catalyst, an alcohol addition reaction catalyst, a liquefied alkanolamine synthesis catalyst, and the like.

[0046]

EXAMPLES The present invention will be described in detail with reference to the following Examples, but the present invention is not limited to these Examples.

Example 1 2.2 ml of a 4 mol / l aqueous solution of sodium hydroxide
And 12.5 g of a 26% by weight aqueous solution of tetramethylammonium hydroxide (abbreviated as TMA) were mixed, and the total amount was made up to 15 ml with distilled water. 15 ml of the aqueous solution was impregnated with 10.7 g of silica beads ("Carrierct Q-10", manufactured by Fuji Silysia Chemical Ltd., 10 to 20 mesh) dried at 120C for one day, and TMA and sodium were placed on the silica beads. The components were loaded. The composition ratio is Si ₁
TMA _0.2 Na _0.05 .

This was transferred onto an evaporating dish, dried in a 90 ° C. water bath, and then dried in an 80 ° C. oven under a nitrogen stream for 3 hours. The obtained precursor was placed in a basket made of a stainless steel net and placed in a hollow Teflon crucible having a volume of 100 ml. 1 g of distilled water was placed in the bottom of the crucible and heated at 170 ° C. for 144 hours. The product taken out after cooling the crucible to room temperature was beads of 10 to 20 mesh size while maintaining the appearance of the silica beads used as the raw material. This is designated as product A.

The product A was pulverized and then subjected to powder X-ray diffraction measurement. As a result, it was found to be NU-1 type silicalite as shown in FIG.

The BET three-point method for nitrogen at 77K (P /
The specific surface area calculated according to (P0 = 0.10, 0.20, 0.30) was 137 m ² / g. Example 2 0.27 g of sodium aluminate was added to T at a concentration of 26% by weight.
Dissolve it in 9.90 g of MA aqueous solution, and make 1 volume with distilled water.
It was 2 ml. Silica beads ("Carrieract Q-10", 1
0-20 mesh) 8.48 g, 12 ml of the aqueous solution
For 1 hour to support sodium aluminate and TMA on the silica beads. The composition ratio is Si ₁ TMA _0.2
Na _0.026 Al _0.02 .

This was transferred to an evaporating dish, dried on a 90 ° C. water bath, and then dried in an 80 ° C. oven under a nitrogen stream for 3 hours. The obtained precursor was crystallized in the same manner as in Example 1. The product taken out was 10 to 20 mesh size beads while maintaining the appearance of the silica beads used as the raw material. This is designated as product B.

The product B was pulverized and then subjected to powder X-ray diffraction measurement to give a diffraction pattern essentially identical to that of FIG.
It was a NU-1 type aluminosilicate.

The BET three-point method for nitrogen at 77K (P /
(P0 = 0.10, 0.20, 0.30), the specific surface area was 92 m ² / g.

After proton ion exchange, the ammonia TPD was measured.
O _2] ^- it can be seen that consists in leaving the peak with a strong acid point of origin was observed, carrying aluminum atoms are taken into the zeolite lattice and T atoms.

[0055]

The NU-1 type binderless zeolite molded article of the present invention contains essentially no binder and therefore has a very high zeolite content in the molded article, and does not bury zeolite in the inorganic binder. . Therefore, zeolite can be used efficiently and there is no adverse effect due to impurities such as an inorganic binder.

According to the method of the present invention, since the precursor to be molded is brought into contact with saturated steam for crystallization,
A NU-1 type binderless zeolite molded body can be easily manufactured.

Further, according to the method of the present invention, since the raw material components do not elute into water, the metal components are efficiently incorporated into the crystal lattice, and as a result, the NU having a composition almost identical to the raw material charged composition is obtained. -1 type crystalline metallosilicate can be produced with good yield.

According to the method of the present invention, the N
Since the U-1 type binderless zeolite molded body directly reflects the properties of the raw silica molded body, it is easy to control the physical properties such as the secondary pore structure. Further, the amount of expensive tetraalkylammonium used can be reduced, and almost no waste liquid is generated, so that there is no need to collect and treat waste liquid, and it is economical.

[Brief description of the drawings]

FIG. 1 shows a CuKα X-ray diffraction pattern of a product A synthesized in Example 1.

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Claims (4)

[Claims] 1. A binderless zeolite molded body, wherein the zeolite is a metallosilicate having a NU-1 type crystal structure. 2. A method according to claim 1 ratio was determined from the nitrogen adsorption measurement according to the BET method surface area of 20 m ² / g to 200 m ² / g
The described binderless zeolite molded article. 3. The following formula (1): Si ₁ (TMA) _x M ¹ _y M ² _z (1) (wherein TMA is tetramethylammonium, M ¹ is an alkali metal, and M ² is a metallosilicate crystal. Represents a metal element incorporated in the skeleton, x is 0.01 to 1, y is 0.0
001 to 1 and z represent a range of 0 to 0.3. A method for producing a NU-1 type binderless zeolite molded body, comprising contacting the zeolite precursor represented by (1) with saturated steam. 4. The raw material containing a tetramethylammonium component, an alkali metal component and, if desired, a metal element component represented by M ² in the above formula (1), is formed by silica molding. 4. The production method according to claim 3, which is a zeolite precursor supported on a body.