JP4812149B2 - Beta-type binderless zeolite molding and method for producing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a beta-type binderless zeolite molding and a method for producing a beta-type binderless zeolite molding. Beta-type zeolite means “BEA-type” zeolite, which is a code indicating a structure by the International Zeolite Society.
[0002]
[Prior art]
Beta-type zeolite is a crystalline metallosilicate typified by crystalline aluminosilicate having 12-membered ring pores disclosed for the first time in US Pat. No. 3,308,069. A crystalline aluminosilicate composed of silicon and aluminum, which is a metal component that constitutes the zeolite crystal skeleton (hereinafter sometimes referred to as T atom), mainly contains Al ³⁺ cations in the crystal lattice for the purpose of controlling its acidity. Substitution with other metal ions is widely performed, and it is generally said to be a beta zeolite including silicalite of the same structure that does not contain aluminum and crystalline metallosilicates in which aluminum is substituted with other metal ions. As a method for synthesizing the beta-type crystalline metallosilicate, a so-called hydrothermal reaction method using an aqueous reaction slurry using tetraethylammonium ions as a template agent as a raw material has been known. However, in the conventional hydrothermal synthesis method, a part of the raw material components are dissolved in water during heating, so that the ratio of the components converted into crystals is inevitably reduced, so the yield is low. Further, since the alkali component is diluted, the crystallization time becomes very long, and such a slow crystallization method tends to grow large crystals. Moreover, since the extraneous metal component (M) other than silicon (Si) is 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 synthesis This causes a problem that the atomic ratio of Si / M in the formed beta zeolite does not always match. Furthermore, industrially, in order to heat the aqueous slurry, a closed container having a relatively large volume with respect to the weight of the generated crystals is required, a large amount of expensive template agent needs to be used, and a large amount of waste liquid. Generation of zeolite, filtration of the zeolite powder, and a complicated firing process.
[0003]
Further, in the case of producing a conventional zeolite molded body, since the moldability of zeolite alone is poor, it has been necessary to first synthesize zeolite powder by a hydrothermal synthesis method and then mold it using an inorganic binder. In this method, it is necessary to select a binder that does not adversely affect the intended use, and in order to obtain sufficient strength, a large amount of an inorganic binder is required. However, there is a problem that the zeolite buried in the binder cannot be effectively used.
[0004]
A method for producing a supported zeolite molded body using an inorganic molded body has also been proposed. For example, in JP-A-11-165074, an aqueous gel comprising tetraethylorthosilicate, tetraethylorthotitanate and tetrapropylammonium hydroxide is supported on a silica carrier and then treated with water vapor under pressure to perform MFI type crystalline titano. Silicate is crystallized on the support. In this method, since it is necessary to use a low-concentration aqueous gel having sufficient fluidity to be supported on the carrier, the amount supported on the carrier is extremely low. That is, the supported zeolite molded body obtained by this method has a problem that the zeolite content is extremely low.
[0005]
Therefore, several methods for producing an aluminosilicate molded body substantially free of a binder have been proposed. For example, Japanese Patent Laid-Open No. 59-162951 (TSZ type aluminosilicate), Japanese Patent Laid-Open No. 61-72620 (MOR type alumino). Several limited types of crystalline binderless aluminosilicate moldings are known, such as silicates) and JP-A-62-2138320 (FAU type aluminosilicate). However, no binderless beta type aluminosilicate molded body has been known.
[0006]
In these methods, crystalline aluminosilicate powder synthesized in advance is used as a secondary raw material, and the binder is crystallized by reacting it with an inorganic solution such as clay mineral or silica alumina sol. Substantially twice hydrothermal synthesis is required to convert to a functional aluminosilicate. For this reason, there are problems in that the process becomes longer and the amount of waste liquid increases.
[0007]
Furthermore, a method for synthesizing a binderless silicalite molded body in which the metal component constituting the crystal skeleton is substantially composed only of silicon or a binderless crystalline metallosilicate molded body composed of T atoms other than aluminum is known. It wasn't.
[0008]
As described above, a beta-type binderless zeolite molding substantially free of a binder and a simple and efficient production method thereof have not been known.
[0009]
[Problems to be solved by the invention]
Accordingly, an object of the present invention has been made in view of the above-described problems, and an object thereof is to provide a beta-type binderless zeolite molded body which substantially contains only zeolite crystals without containing an inorganic binder.
[0010]
Another object of the present invention is to provide a simple and efficient method for producing a beta-type zeolite molded body that does not use a binder.
[0011]
[Means for Solving the Problems]
As a result of intensive studies on the beta-type binderless zeolite moldings, the present inventors have, for example, supported a tetraethylammonium component, an alkali metal component, and other metal components together on a silica molding, and then saturated water vapor under specific conditions. The beta-type binderless zeolite molded body that essentially contains no binder and crystallizes the entire amount of the silica component while maintaining the shape of the silica molded body and simultaneously incorporates the metal component as T atoms. Thus, the present invention was completed.
[0012]
That is, the present invention relates to a binderless zeolite molding, wherein the zeolite has a beta crystal structure.
[0013]
The binderless zeolite molded body, for example, the specific surface area determined from nitrogen adsorption measurements by BET method, which is binderless zeolite molded body is 300m ² / g~950m ² / g.
[0014]
The binderless zeolite molded body, for example, the pore diameter determined by mercury intrusion porosimetry has pores of more than 4 nm, the surface area of the pores is a 2m ² / g~200m ² / g, and the fine It is a binderless zeolite molded body having a pore volume of 0.10 ml / g to 1.5 ml / g.
[0015]
Another invention of the present invention is represented by the following formula (1):
Si ₁ (TEA) _x M ¹ _y M ² _z (1)
(Wherein TEA is tetraethylammonium, M ¹ is an alkali metal, M ² is a metal element incorporated into the metallosilicate crystal skeleton, x is 0.005 to 1, y is 0.0001 to 1, and z is 0.00. Represents a range of 0005 to 0.4.)
It is related with the manufacturing method of the binderless zeolite molded object characterized by making a zeolite precursor represented by 80-260 degreeC saturated steam contact.
[0016]
The zeolite precursor is preferably a zeolite precursor formed by supporting a raw material containing a tetraethylammonium component, an alkali metal component, and a metal component incorporated in a metallosilicate crystal skeleton on a silica molding. .
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Details of the present invention will be described below.
[0018]
The zeolite precursor used in the method for producing a binderless zeolite molding of the present invention is represented by the following formula (1):
Si ₁ (TEA) _x M ¹ _y M ² _z (1)
(Wherein TEA is tetraethylammonium, M ¹ is an alkali metal, M ² is a metal element incorporated into the metallosilicate crystal skeleton, x is 0.005 to 1, y is 0.0001 to 1, and z is 0.00. Represents a range of 0005 to 0.4.)
If it is a composition represented by, it will not specifically limit. In the formula (1), M ¹ represents an alkali metal such as lithium, sodium, or potassium, and M ² represents a metal element incorporated in the metallosilicate crystal skeleton, such as boron, aluminum, titanium, iron, zinc, gallium, and indium. Represents at least one element selected from the group consisting of Further, in the formula (1), it is preferable that x is 0.001-1, y is 0.0001-1, z is 0.0005-0.3, and further in the formula (1) , X is preferably 0.002 to 0.8, y is 0.0002 to 0.5, and z is preferably 0.001 to 0.2.
[0019]
The method for preparing the zeolite precursor is not particularly limited, and a raw material containing a tetraethylammonium component, an alkali metal component, and one or more metal components incorporated in a metallosilicate crystal skeleton supported as desired is formed into silica. A method of supporting the body is preferred.
[0020]
When the tetraethylammonium component and the alkali metal component are supported on the silica molded body, a binderless beta-type silicalite molded body composed of silicon-only T atoms can be produced. In addition to the two components, In the case where at least one metal component selected from the group consisting of boron, aluminum, titanium, iron, zinc, gallium and indium is supported, a beta-type binderless crystalline metallosilicate molded body in which this is incorporated as a T atom is obtained. Can be manufactured.
[0021]
The silica molded body is not particularly limited, and a commercially available 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 Those in the range of 800 m ² / g are used. This is because if the specific surface area is too small, a long time is required for crystallization, and the degree of crystallization may deteriorate.
[0022]
Further the silica molded body, for example, the pore diameter determined by mercury intrusion porosimetry has pores of more than 4 nm, surface area and pore volume due to pores each ^{5m 2 / g~1000m 2 / g,} 0 was .10ml / g~1.5ml / g, and preferably from 20m ² / g~800m ² /g,0.15ml/g~1.3ml/g.
[0023]
Examples of the tetraethylammonium component include tetraethylammonium halides and hydroxides, and tetraethylammonium hydroxide is usually used. By using tetraethylammonium hydroxide, it is possible to efficiently synthesize beta-type zeolite.
[0024]
Examples of the alkali metal component include lithium, sodium, potassium, and the like, and alkali metal components in hydroxides, halides, silica moldings and / or metal salt compounds thereof can also be used.
[0025]
When synthesizing a beta-type binderless crystalline metallosilicate molded body, a metal salt that becomes a T atom is supported on the silica molded body together with the tetraethylammonium component and the alkali metal component. Examples of these metal salts include nitrates such as boron, aluminum, titanium, iron, zinc, gallium, and indium, sulfates, halides, oxoacid salts, and hydroxides. It is preferable to use it. In addition, the metal salt is preferable in that the use of a metal salt of at least one metal selected from the group consisting of boron, aluminum, iron, zinc and gallium can significantly shorten the crystallization time. These metal components are converted into a binderless metallosilicate by being incorporated into the zeolite framework during crystallization.
[0026]
A method for supporting a raw material material containing a tetraethylammonium component, an alkali metal component, and one or more metal components incorporated in a metallosilicate crystal skeleton supported as desired on the silica molding is not particularly limited. However, since it is desirable to uniformly support the raw material in the silica molded body, it is usually performed by impregnating with an aqueous solution and then drying. As an example, a predetermined amount of each component is made into a uniform aqueous solution, and is prepared and impregnated so as to have an aqueous solution amount that matches 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 divided and supported in several times. Will not be affected.
[0027]
The drying temperature after impregnating the aqueous solution is not particularly limited, but is preferably 20 ° C. to 150 ° C., more preferably 50 ° C. to 120 ° C., in that the decomposition of the tetraethylammonium salt is low and the water content is suppressed efficiently. Will be implemented. The water content of the precursor is preferably 30% or less, and more preferably in the range of 20% to 0.1% in that the supported component does not elute during crystallization and the yield is good.
[0028]
Further, the drying method is not particularly limited, and the drying can be carried out under any conditions of reduced pressure and normal pressure. Since it is easy to dry under an air stream at normal pressure, it is preferable.
[0029]
The production method of the present invention is characterized in that the zeolite precursor is brought into contact with saturated steam.
[0030]
The temperature of the saturated water vapor is not particularly limited, and it is 80 to 260 ° C. in that a beta-type binderless zeolite molded body having a high crystallization rate and less decomposition of the contained tetraethylammonium component and high crystallinity can be obtained. A range is preferable and 100 to 230 degreeC is more preferable. If the crystallization temperature is too high, mixed crystals with other minerals such as MFI type zeolite may be formed.
[0031]
The contact time with the saturated water vapor may be a short time, usually 2 to 300 hours, preferably 3 to 150 hours. If the crystallization time is too short, the crystallinity is lowered, and if it is too long, a mixed crystal with other minerals may be formed.
[0032]
The method and apparatus for heating the zeolite precursor in contact with saturated steam is not particularly limited. For example, it can be carried out by placing the precursor in the hollow of the pressure vessel and enclosing water corresponding to the saturated water vapor amount determined by the reaction temperature and the volume of the vessel at the bottom of the vessel, followed by heating in a thermostatic chamber, The embodiment is not limited to this. The precursor may be placed in a container and a sealed container with water on the outside may be used. Alternatively, the precursor may be continuously synthesized by a fixed bed reactor or a moving bed reactor in which the precursor is brought into contact with saturated steam. You can also
[0033]
By using the production method of the present invention, the zeolite precursor can be crystallized by being brought into contact with saturated steam without being dispersed in water and subjected to a hydrothermal reaction. Accordingly, it is possible to convert the supported metal component into a beta-type zeolite having T atoms. As a result, the silica molded body, which is the raw material, is converted into zeolite while maintaining its shape, so the zeolite produced is essentially free of binder, and it is assumed that a beta-type binderless zeolite molded body can be easily produced. Is done.
[0034]
Since no binder is used in the production method of the present invention, the beta zeolite molded body synthesized by the production method of the present invention has a very high crystallinity with a zeolite content of almost 100%. By selecting an appropriate composition ratio of precursor, crystallization temperature and crystallization time from the above conditions, the crystallinity of the molded product can be controlled, for example, 95% or more, preferably 98% or more. . The crushing strength can be controlled by the degree of crystallinity.
[0035]
Further, in the production method of the present invention, a silica molded body is molded into an arbitrary shape such as a spherical shape, a cylinder shape, or a ring shape by a conventional method, and then converted into a zeolite by the method according to the present invention, whereby a spherical shape, a cylinder shape, a ring A binderless zeolite molded body having an arbitrary shape such as a mold can be produced. Since the silica support itself as a raw material is converted into zeolite as it is, a binderless zeolite molded body maintaining the shape of the silica molded body can be obtained.
[0036]
Moreover, in the manufacturing method of this invention, not only the external appearance of a raw material silica molded object is hold | maintained but crushing strength, macropore distribution, etc. are reflected. For this reason, the physical property of a binderless zeolite molding can be easily controlled by controlling the physical property of the silica molding used for a raw material by a conventional method.
[0037]
Moreover, the binderless zeolite molding of the present invention is
(1) the zeolite has a BEA type crystal structure, and (2) the composition ratio (atomic ratio) between silicon and the metal constituting the zeolite crystal structure is 0.0005 It is characterized by being in the range of 0.4.
[0038]
The zeolite in the molded body of the present invention has a BEA type crystal structure. This can be confirmed by powder X-ray diffraction measurement or the like. The structure of the BEA type zeolite forms a zeolite crystal skeleton by three-dimensionally bonding a TO ₄ tetrahedron having four oxygen atoms coordinated at the apex with T atoms as the center. For this reason, silicalite whose T atom is composed only of silicon is electrically neutral and therefore does not exhibit solid acidity. It is well known that when Si ⁴⁺ is replaced by another valent metal, cations such as protons exist in the crystal to electrically neutralize the TO ₄ anion, and thereby solid acidity is expressed. ing. These cations can be easily ion-exchanged by ordinary operations. Further, the amount of solid acidic acid and the acid strength that are expressed can be controlled by the amount and type of the element introduced as T atom. The solid acidity can be evaluated by a temperature desorption (TPD) method of ammonia.
[0039]
In the molded body of the present invention, the composition ratio (atomic ratio) of the metal components constituting the zeolite crystal structure in the molded body is in the range of 0.0005 to 0.4, preferably 0.001 to silicon 1. It is characterized by being in the range of 0.2.
[0040]
The molded body of the present invention are, for example, the specific surface area determined from nitrogen adsorption measurements by the BET method was 300m ² / g~950m ² / g, preferably in the range of 320m ² / g~850m ² / g.
[0041]
The molded body of the present invention has, for example, secondary pores having a pore diameter of 4 nm or more determined by a mercury intrusion method, and the surface area and pore volume of each pore are 2 m ² / g to ²⁰⁰ m ² / g, a 0.10ml / g~1.5ml / g, preferably in the range of 3m ² / g~170m ² /g,0.13ml/g~1.3ml/g.
[0042]
The molded body of the present invention can be easily and efficiently manufactured by, for example, the above-described method for manufacturing a binderless zeolite molded body.
[0043]
Examples of the shape of the molded body of the present invention include a spherical shape, a cylinder shape, and a ring shape, but are not particularly limited.
[0044]
The molded body of the present invention can be used as an adsorbent, a catalyst for a chemical reaction, or a catalyst carrier in various chemical processes because the shape, size, macropore distribution, etc. can be easily controlled. It is suitably used for an alkylation reaction catalyst, 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 liquid ammonium alkanolamine synthesis catalyst, and the like.
[0045]
【Example】
The present invention is specifically described by the following examples, but the present invention is not limited to these examples.
[0046]
Example 1
A 35 wt% aqueous solution of tetraethylammonium hydroxide (abbreviated as TEA) 13.82 g and sodium aluminate 0.32 g were dissolved in distilled water to make 14 ml. After impregnating 9.87 g of silica beads (Fuji Silysia Chemical "Caractect Q-10", 10-20 mesh) dried for one day at 120 ° C for 1 hour in the above aqueous solution, Then, TEA and sodium aluminate were supported on the silica beads. The composition ratio is Si ₁ TEA _0.20 Na _0.026 Al _0.02 .
[0047]
The obtained precursor was put in a cage made of a stainless steel net and placed in the hollow of a Teflon crucible having a volume of 100 ml. 1 g of distilled water was added to 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 washed with 300 ml of a 1 mol / l aqueous ammonium nitrate solution, and then baked at 550 ° C. for 6 hours in an air stream to remove TEA-derived organic components. .72 g was obtained. This is product A.
[0048]
The shape of the product A was 10 to 20 mesh size beads while maintaining the appearance of the silica beads used as a raw material. As a result of powder X-ray diffraction measurement after pulverizing the product A, it was a beta crystalline aluminosilicate as shown in FIG.
[0049]
The specific surface area calculated by the BET three-point method of nitrogen at 77 K (P / P0 = 0.015, 0.06, 0.10) was 693 m ² / g. Further, as a result of measuring the pore distribution by the mercury intrusion method, the pore distribution curve shown in FIG. 2 was given, and the total macropore volume of 4 nm or more was 0.33 ml / g, and the surface area of the macropore was 65 m ² / g. The pore volume in the range of pore diameters of 10 to 80 nm (average pore diameter of 30 nm) is 0.22 ml / g, and has a sharp pore distribution occupying about 68% of the total macropore volume of 4 nm or more. Recognize.
[0050]
Example 2
Sodium aluminate (0.53 g) was dissolved in 14.01 g of a 35 wt% aqueous tetraethylammonium hydroxide solution (abbreviated as TEA). After impregnating 10.0 g of silica beads (Fuji Silysia Chemical "Caractect Q-30", 10-20 mesh) dried for one day at 120 ° C for 1 hour in the above aqueous solution, dried at 80 ° C. Then, TEA and sodium aluminate were supported on the silica beads. The composition ratio is Si ₁ TEA _0.20 Na _0.043 Al _0.033 .
[0051]
The obtained precursor was crystallized in the same manner as Example 1 at 170 ° C. for 20 hours.
The product taken out after cooling was baked at 550 ° C. for 6 hours in an air stream to remove TEA-derived organic components, thereby obtaining 10.5 g of a white product. This is product B.
[0052]
The shape of the product B was 10 to 20 mesh size beads while maintaining the appearance of the silica beads used as a raw material. As a result of powder X-ray diffraction measurement after pulverizing the product B, it gave a diffraction pattern essentially the same as that of the product A shown in FIG. 1, and it was a beta crystalline aluminosilicate.
[0053]
The specific surface area calculated by the BET three-point method of nitrogen at 77 K (P / P0 = 0.01, 0.06, 0.10) was 630 m ² / g. Moreover, as a result of measuring the pore distribution by the mercury intrusion method, the pore distribution curve shown in FIG. 3 was given, the total macropore volume of 4 nm or more was 0.43 ml / g, and the surface area of the macropore was It was 59 m ² / g. The pore volume in the range of pore diameters of 10 to 80 nm (average pore diameter of 30 nm) is 0.28 ml / g, and has a sharp pore distribution occupying about 66% of the total macropore volume of 4 nm or more. Recognize.
[0054]
【The invention's effect】
Since the beta-type binderless zeolite molding of the present invention essentially contains no binder, the zeolite content in the molding is extremely high, and the zeolite is not buried in the inorganic binder. For this reason, there is a feature that zeolite can be efficiently used and there is no adverse effect caused by impurities such as an inorganic binder.
[0055]
According to the method of the present invention, crystallization is carried out by bringing the molded precursor and saturated steam into contact with each other, so that a beta-type binderless zeolite molded body can be easily produced.
[0056]
Further, according to the method of the present invention, the time required for crystallization is short, and since the raw material component does not elute in water, the metal component is efficiently taken into the crystal lattice. A beta-type crystalline metallosilicate having a composition almost identical to the composition can be produced with good yield.
[0057]
In addition, according to the method of the present invention, the produced beta-type binderless zeolite molded body reflects the properties of the raw silica molded body as it is, and therefore it is easy to control physical properties such as the secondary pore structure. Further, since the amount of expensive tetraalkylammonium used can be reduced and almost no waste liquid is generated, there is no need for recovery and waste liquid treatment, which is economical.
[Brief description of the drawings]
FIG. 1 shows a CuKα X-ray diffraction pattern (2θ = 5 to 40 °) of product A.
FIG. 2 shows a pore distribution curve of product A by mercury porosimetry.
FIG. 3 shows a pore distribution curve of product B by mercury porosimetry.

Claims (4)

A zeolite precursor obtained by supporting a raw material component including a tetraethylammonium component, an alkali metal component , and a metal element component represented by M ² of the following formula (1) and incorporated in a metallosilicate crystal skeleton on a silica molding. The body has the following formula (1):
Si ₁ (TEA) _x M ¹ _y M ² _z (1)
(Wherein, TEA is tetraethylammonium, ^{M 1} is an alkali metal, ^{M 2} represents a metal element incorporated in the metallosilicate crystals backbone, x is 0.005 to 1, y is 0.0001 to 1, z is 0. Represents a range of 0005 to 0.4.)
By bringing the zeolite precursor into contact with saturated water vapor, the entire amount of the silica molded body is converted into zeolite while maintaining its shape, and the metal element incorporated in the metallosilicate crystal skeleton is contained in the skeleton. A method for producing a beta-type binderless zeolite molding, which is incorporated.   2. The production method according to claim 1, wherein the metal element component comprises at least one metal element selected from the group consisting of boron, aluminum, titanium, iron, zinc, gallium, and indium. The specific surface area of the binderless zeolite molded body obtained from the nitrogen adsorption measured by the BET method is 300m ² / g~950m ² / g, The process according to claim 1 or 2. The binderless shaped zeolite, the pore diameter determined by mercury intrusion porosimetry has pores of more than 4 nm, the surface area of the pores is a 2m 2 ^/ g~200m 2 ^{/ g,} and the pore The manufacturing method of any one of Claims 1-3 whose pore volume is 0.10 ml / g-1.5 ml / g.

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