JP2642893B2 - Method for producing X-type zeolite single crystal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method for producing an X-type zeolite single crystal. More specifically, the present invention provides an economically advantageous X-type zeolite single crystal having a large crystallite diameter and high purity using ordinary industrial raw materials without using an organic chemical such as triethanolamine. The present invention relates to an industrial method for efficiently producing a product.

[0002]

BACKGROUND OF THE INVENTION Zeolites, the general formula _{M 2 / n O · Al 2} O 3 · xSiO 2 · yH 2 O (M in formula Na, K, Ca or Ba, n is the valence of M,
x is 2 to 10 and y is 2 to 7) is an alkali metal or alkaline earth metal aluminosilicate represented by the following formula, wherein a three-dimensional network formed by (Al, Si) O ₄ tetrahedra sharing the vertices: In the pores of the structure, alkali metal or alkaline earth metal, having a structure containing water molecules, for example, builder, paper filler, soil conditioner,
It is widely used in many fields as a molecular sieve, a hygroscopic agent, a catalyst and its carrier.

[0003] These zeolites are roughly classified into natural products and synthetic products. Synthetic zeolites include, for example, A type, X type, Y type, L type, etc., depending on their composition and structure. The X-type zeolite in this is usually of the general formula Na ₂ O.Al ₂ O _3.
(2-3) It has a faujasite-like structure having a composition of SiO ₂ .yH ₂ O, and a method for producing a single crystal thereof is described in, for example, (1) “Journal of Crystal.
Growth (J. Crystal Growth) # 8
Vol. 291-294 (1971) and (2)
"Zeolites" Volume 13, Volume 64
5-653 pages (1993). However, in these methods, it is necessary to use triethanolamine, which causes a deterioration in working environment, as an additive in order to suppress by-products of zeolites other than X-type zeolite. Not necessarily suitable. And (2)
In order to obtain X-type zeolite having a large crystallite diameter, the method of (1) requires the use of extremely high-purity silica. For example, alumina and iron in silica
It is necessary to keep 0 ppm or less, calcium 20 ppm or less, and magnesium 2 ppm or less, which inevitably increases the production cost.

[0004]

SUMMARY OF THE INVENTION The present invention overcomes the drawbacks of the conventional method for producing a single crystal of X-type zeolite and uses an ordinary industrial raw material to convert an organic chemical such as triethanolamine. An object of the present invention is to provide an industrial method for economically, advantageously, and efficiently producing an X-type zeolite single crystal having a large crystallite size and a high purity without using it.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies on a method for producing an X-type zeolite single crystal, and as a result, using sodium hydroxide, sodium aluminate, silica and water as raw materials, After preparing a mixture containing at a ratio of at room temperature, it was found that it can be easily produced by crystallization at a predetermined temperature, and the present invention was completed based on this finding.

That is, the present invention relates to sodium hydroxide,
Sodium aluminate, silica and water were converted to SiO ₂ / A
The l ₂ O ₃ molar ratio is 2 to 8, and the Na ₂ O / SiO ₂ molar ratio is 0.
X is characterized in that a raw material mixture containing 5 to 4 and a H ₂ O / Na ₂ O molar ratio of 70 to 170 is prepared at room temperature, and then crystallized at a temperature of 50 to 120 ° C. It is intended to provide a method for producing a type zeolite single crystal.

In the method of the present invention, sodium hydroxide, sodium aluminate, silica and water are used as raw materials. The sodium aluminate is preferably used in the form of an aqueous solution obtained by adding aluminum hydroxide to an aqueous sodium hydroxide solution and dissolving by heating. Further, various kinds of silica can be used, but colloidal silica, silica sol and fumed silica are particularly preferable. Examples of such silica include colloidal silica VN3 [produced by Nippon Silica Industry Co., Ltd.
SiO ₂ = 89% by weight], Silica sol SA [manufactured by Catalyst Chemical Industry Co., Ltd., SiO ₂ = 31% by weight], Aerosil
-200 [manufactured by Nippon Aerosil Co., Ltd.] and the like are commercially available, and any of them can be used.

In the present invention, first, using the above-mentioned raw materials, the molar ratio of SiO ₂ / Al ₂ O ₃ is 2 to 8, and Na ₂ O / Si
O ₂ molar ratio of 0.5-4 and H ₂ O / Na ₂ O molar ratio of 7
A raw material mixture is prepared so as to be 0 to 170. If each molar ratio deviates from the above range, it is difficult to obtain an X-type zeolite single crystal having a large crystallite diameter and high purity. The preferred range of the molar _{ratio, SiO 2 / Al 2 O 3} 2.5~6, Na
₂ O / SiO ₂ 1.5-2.5 and H ₂ O / Na ₂ O 10
0 to 130.

In the preparation of this raw material mixture, it is necessary to limit the number of nuclei generated in the initial stage of crystallization in order to form a single crystal X-type zeolite as large as possible. It is desirable to shorten the mixing and aging time as much as possible, preferably to complete the preparation of the raw material mixture within 10 minutes, more preferably within 5 minutes.

Next, the raw material mixture thus prepared is heated at a temperature in the range of 50 to 120 ° C. for about 2 to 20 days to be crystallized, thereby obtaining a highly pure X-type having a large crystallite diameter. A zeolite single crystal is obtained. The crystallite size of the X-type zeolite single crystal obtained by such a method is usually in the range of 45 to 70 μm, and its composition is represented by the formula Na ₂ O.Al ₂ O _3. (2 it can be represented by to 3) SiO _2.

[0011]

According to the present invention, an X-type zeolite single crystal having a large diameter and high purity can be efficiently produced using ordinary industrial raw materials without using an organic chemical such as triethanolamine. can do. Therefore, the method of the present invention is highly valuable as an industrial method for producing X-type zeolite single crystals.

[0012]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In addition, the sodium aluminate aqueous solution used as a raw material is aluminum hydroxide [manufactured by Mitsui Alumina Manufacturing Co., Ltd.] for producing alumina for electrolysis.
Al ₂ O ₃ : 63.4% by weight] was heated and dissolved with a 48% by weight aqueous sodium hydroxide solution and water.

Example 1 An aqueous sodium hydroxide solution (Na ₂ O: 36.49% by weight) 57.89 was placed in a Teflon reaction vessel having a capacity of 1 liter.
g, sodium aluminate aqueous solution (Na ₂ O: 20.1
1 wt%, Al ₂ O _3: 18.48 wt%) 45.00 g
And 755.3 g of distilled water, and the mixture was stirred well with a Teflon rod. Then, while stirring the mixed solution with a Teflon rod, silica sol SA [catalyst Chemical Industry Co., Ltd., SiO ₂ : 32.2] was added thereto. % By weight, Na ₂ O: 0.
20% by weight] 74.9 cm ³ was injected from a burette. Further, the mixture is mixed with an ultra disperser for 1 minute.
The mixture was stirred for 3 minutes, and 3 minutes after the completion of the injection of the silica sol SA, the reaction vessel containing the mixture was charged into a crystallization thermostat at 100 ° C. The composition of this mixture is SiO
₂ / Al ₂ O ₃ = 6, Na ₂ O / SiO ₂ = 1.0, H ₂ O /
Na ₂ O = 100.

After 6 days, the contents of the container were filtered, washed and dried, and then absorbed in a humidity box having a relative humidity of 75%. 1.5 g of the sufficiently absorbed product was pulverized for 5 minutes using a mill, and 1.000 g of the pulverized product and 0.200 g of anatase-type titanium oxide were mixed using a magnetic mortar and a pestle. When the X-ray diffraction intensity of this mixed powder sample was compared with a sample obtained in the same manner using Y-type zeolite LZ-Y52 (manufactured by UCC), the content of faujasite-type zeolite was 64.7. %Met.

The content x of the faujasite-type zeolite based on the X-ray diffraction intensity is expressed by the following equation: x (%) = (ΣIn / Ia) / (ΣIn / Ia) _LZ-Y52
× 100. Here, ΔIn is ten diffraction lines of faujasite-type zeolite, (111), (220), (3).
11), (331), (511), (440), (53)
3) The sum of the peak heights of (642), (660), and (555), and Ia indicates the peak height of the (101) diffraction line of anatase-type titanium oxide. Subscript LZ-Y
The value indicated by 52 is a standard Y-type zeolite LZ-Y5.
2 is a value obtained by pulverizing for 5 minutes with a rake machine. When a part of the product was observed with a scanning electron microscope, the diameter of the X-type zeolite single crystal was 48 μm in a large one.

Example 2 An aqueous sodium hydroxide solution (Na ₂ O: 32.78% by weight) was placed in a stainless steel reaction vessel having a capacity of 350 cm ^3.
5.93 g of a sodium aluminate aqueous solution (Na ₂ O:
19.83% by weight, Al ₂ O ₃ : 18.60% by weight) 1
After 7.63 g and 224.7 g of distilled water were charged and stirred well with a Teflon rod, the mixed solution was stirred with a Teflon rod, and silica sol SA [catalyst Chemical Industry Co., Ltd., SiO ₂ : 32.2% by weight, Na ₂
O: 0.20 wt% was injected 30 cm ³ from the pipette. Further, the mixture is mixed with an ultra disperser for 1 minute.
The mixture was stirred for 6 minutes, and 6 minutes after the completion of the injection of the silica sol SA, the reaction vessel containing the mixture was charged into a crystallization constant temperature bath at 100 ° C. The composition of this mixture is SiO
₂ / Al ₂ O ₃ = 6, Na ₂ O / SiO ₂ = 1.0, H ₂ O /
Na ₂ O = 80.

After 4 days, the contents of the container were filtered, washed and dried, and then absorbed in a humidity box having a relative humidity of 75%. When the content of the faujasite-type zeolite in the sufficiently absorbed product was measured in the same manner as in Example 1, the content of the faujasite-type zeolite was 76.6%.
Met. Also, the diameter of the single crystal by scanning electron microscope,
In the case of a large one, it was 50 μm. FIG. 1 is a scanning electron micrograph of this crystal.

Example 3 An aqueous solution of sodium hydroxide (Na ₂ O: 32.38% by weight) 51.81 was placed in a 1-liter Teflon-made reaction vessel.
g, sodium aluminate aqueous solution (Na ₂ O: 19.8)
(3% by weight, Al ₂ O ₃ : 18.60% by weight) 20.57 g
Then, 774.5 g of distilled water and 774.5 g of distilled water were charged, and the mixture was stirred well with a Teflon rod. Then, while stirring the mixed solution with a Teflon rod, silica sol SA [manufactured by Catalyst Chemical Industry Co., Ltd., SiO ₂ : 32.2. % By weight, Na ₂ O: 0.
20 wt% was injected 35 cm ³ from the pipette. Further, this mixture was stirred with an ultra disperser for 1 minute, and after closing the lid of the reaction vessel, the reaction vessel containing the mixture was immediately put into a 100 ° C. crystallization thermostat. The composition of this mixture is represented by a molar ratio of SiO ₂ / Al ₂ O ₃ =
6, Na ₂ O / SiO ₂ = 1.5, H ₂ O / Na ₂ O = 14
It was 0.

After 8 days, the contents of the reaction vessel are filtered, washed,
After drying, they were absorbed in a humidity box of 75% relative humidity. The content of the faujasite-type zeolite in the sufficiently absorbed product was 25.0%. The diameter of the single crystal measured by a scanning electron microscope was 68 μm in the case of a large crystal.

EXAMPLE 4 51.58 sodium hydroxide aqueous solution (Na ₂ O: 37.17% by weight) was placed in a 1-liter reaction vessel made of Teflon.
g, sodium aluminate aqueous solution (Na ₂ O: 19.8)
23.50 g) ( ₃ % by weight, Al ₂ O ₃ : 18.60% by weight)
And 753.8 g of distilled water, and the mixture was stirred well with a Teflon rod. Then, while stirring the mixed solution with a Teflon rod, silica sol SA [catalyst Chemical Industry Co., Ltd., SiO ₂ : 32.2. % By weight, Na ₂ O: 0.
20 wt% was injected 40 cm ³ from the pipette. Further, this mixture was stirred for 1 minute with an ultra disperser, and 5 minutes after the completion of the silica sol SA injection, the reaction vessel containing the mixture was put into a 100 ° C. crystallization thermostat. The composition of this mixture is SiO ₂ / Al ₂ O in a molar ratio.
₃ = 6, Na ₂ O / SiO ₂ = 1.5, H ₂ O / Na ₂ O =
120.

After 7 days, the contents of the reaction vessel are filtered, washed,
After drying, they were absorbed in a humidity box of 75% relative humidity. The content of faujasite-type zeolite in the product that had sufficiently absorbed moisture was 82.0%. In addition, the diameter of the single crystal measured by a scanning electron microscope was 46 μm in a large one.

Example 5 An aqueous solution of sodium hydroxide (Na ₂ O: 36.49% by weight) 56.51 was placed in a Teflon-made reaction vessel having a capacity of 1 liter.
g, sodium aluminate aqueous solution (Na ₂ O: 20.1
1 wt%, Al ₂ O _3: 18.48 wt%) 18.03 g
And 846.2 g of distilled water, and the mixture was stirred well with a Teflon rod. Then, the mixed solution was stirred with a Teflon rod, and the mixture was mixed with silica sol SA [manufactured by Catalyst Chemical Industry Co., Ltd., SiO ₂ : 32.2]. % By weight, Na ₂ O: 0.
20 wt% was injected 30 cm ³ from the burette.
Further, this mixture was stirred with an ultra disperser for 1 minute, and 3 minutes after the completion of the silica sol SA injection, the reaction vessel containing the mixture was put into a 100 ° C. crystallization thermostat. The composition of this mixture is SiO ₂ / A in molar ratio.
l ₂ O ₃ = 6, Na ₂ O / SiO ₂ = 2.0, H ₂ O / Na ₂
O = 130.

After 6 days, the contents of the reaction vessel are filtered, washed,
After drying, they were absorbed in a humidity box of 75% relative humidity. The content of faujasite-type zeolite in the product that had sufficiently absorbed moisture was 82.0%. In addition, the diameter of the single crystal measured by a scanning electron microscope was 46 μm in a large one.

Example 6 An aqueous sodium hydroxide solution (Na ₂ O: 36.49% by weight) 56.94 was placed in a Teflon-made reaction vessel having a capacity of 1 liter.
g, sodium aluminate aqueous solution (Na ₂ O: 20.1
1 wt%, Al ₂ O _3: 18.48 wt%) 14.03g
Then, 828.9 g of distilled water was charged, and the mixture was stirred well with a Teflon rod. Then, while stirring the mixed solution with a Teflon rod, silica sol SA [catalyst Chemical Industry Co., Ltd., SiO ₂ : 32.2] was added thereto. % By weight, Na ₂ O: 0.
20 wt% was injected 30 cm ³ from the burette.
Further, this mixture was stirred with an ultra disperser for 1 minute, and 3 minutes after the completion of the silica sol SA injection, the reaction vessel containing the mixture was put into a 100 ° C. crystallization thermostat. The composition of this mixture is SiO ₂ / A in molar ratio.
l ₂ O ₃ = 6, Na ₂ O / SiO ₂ = 2.5, H ₂ O / Na ₂
O = 130.

After 6 days, the contents of the reaction vessel are filtered, washed,
After drying, they were absorbed in a humidity box of 75% relative humidity. The content of faujasite-type zeolite in the product that had sufficiently absorbed moisture was 82.0%. In addition, the diameter of the single crystal measured by a scanning electron microscope was 46 μm in a large one.

[Brief description of the drawings]

FIG. 1 is a scanning electron micrograph of an example of an X-type zeolite single crystal obtained by the method of the present invention.

Claims (5)

(57) [Claims] 1. A method according to claim 1, wherein sodium hydroxide, sodium aluminate, silica and water are mixed at a SiO ₂ / Al ₂ O ₃ molar ratio of 2 to 2.
8, Na ₂ O / SiO ₂ molar ratio of 0.5 to 4 and H ₂ O /
A raw material mixture containing Na ₂ O at a molar ratio of 70 to 170 was prepared at room temperature, and then 50 to 120 ° C.
A method for producing a single crystal of X-type zeolite, characterized by crystallizing at a temperature. 2. The raw material mixture has a SiO ₂ / Al ₂ O ₃ molar ratio of 2.5 to 6, a Na ₂ O / SiO ₂ molar ratio of 1.5 to 2.5, and a H ₂ O / Na ₂ O molar ratio of 100 to 100. The method according to claim 1, wherein the number is 130. 3. The method according to claim 1, wherein the silica is colloidal silica, silica sol or fumed silica. 4. The method according to claim 1, wherein the preparation of the raw material mixture is completed at room temperature within 10 minutes. 5. The raw material mixture is heated at a temperature of 50 to 120 ° C. for 2 hours.
The method according to any one of claims 1 to 4, wherein the crystallization is performed by heating for up to 20 days.