JP3192677B2 - Method for producing crystalline silicate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel method for producing a crystalline silicate, and more particularly to a method for producing a crystalline silicate having a specific chemical composition in the absence of organic additives.

[0002]

2. Description of the Related Art Zeolite has a large number of three-dimensional structures and is used as a molecular sieve for separating adsorbents and gases. Recently, catalysts for hydrocarbon conversion such as cracking and isomerization of hydrocarbons, and denitration catalysts, etc. It has become widely used as. Usually the zeolite is a crystalline aluminosilicate, the ratio of total aluminum and silicon atoms to oxygen atoms is 1: SiO ₄ are linked by sharing of oxygen atoms at 2 and AlO ₄ ^- tetrahedra rigid three-dimensional structure Have.

[0003] On the other hand, even if a trivalent cation having the same radius as the ionic radius of Al is used instead of Al, a tetrahedron of the trivalent cation is formed in the same form as the SiO ₄ tetrahedron in the zeolite structure. (Tokuhei 2-356)
No. 92).

[0004] It has been recognized that the conversion of some or all of Al in the zeolite to a transition metal significantly changes the catalytic performance. For example, in the aromatic conversion reaction of methanol or other oxygen-containing organic compounds, in a conventional zeolite called ZSM-5, durene as a by-product is a few%.
But it produces, when using such a crystalline silicate, as a result of C ₁₀ or more aromatic products not throat generate N殆such durene is obtained. Further, in the direct decomposition reaction of nitrogen oxides (2N0 → N ₂ + O ₂ ), such a crystalline silicate subjected to Cu ion exchange can be used in a conventional ZSM.
It has been reported that a side reaction is suppressed as compared with zeolite referred to as -5, and only the above-mentioned reaction proceeds selectively (Japanese Patent Application No. 01-281996).

Hitherto, such a crystalline silicate has been produced by a hydrothermal synthesis method using an organic nitrogen-containing compound or the like. Examples of the organic substances used include i) primary amines: n-propylamine, monoethanolamine, etc. ii) secondary amines: dipropylamine, diethanolamine, etc. iii) tertiary amines: tripropylamine Iv) Other organic nitrogen compounds: pyridine, pyrazine and the like. Examples of organic substances other than the organic nitrogen compounds include alcohols such as ethanol and methanol, ketones such as acetone, and ethers such as diethyl ether. And esters are also used. It is said that the above-mentioned organic substance acts as a crystallization accelerator, and that the organic substance is present at the intersection of the pores, thereby enabling a high-quality silicate to be obtained as a crystal nucleus.

However, the above-mentioned organic compounds are expensive,
In some cases toxicity is a problem. When the crystalline silicate is synthesized, the organic compound is taken into the pores, and even if a baking operation is performed to remove the organic silicate, an organic substance may remain or instantaneous high-temperature combustion may occur, resulting in demetalization ( A
1, Fe... etc.).

[0007]

In order to eliminate these disadvantages, there has been proposed a method for producing a crystalline silicate without using an organic additive. For example, a method of producing a crystalline silicate by holding an aqueous raw material mixture comprising silica, alumina, alkali metal salt and the like containing no organic additives at 80 to 210 ° C. for 40 to 200 hours under natural pressure (Japanese Patent Publication No. Sho 56)
-49851 JP) have been proposed, which coexist byproducts mordenite in the crystal, it is impossible to get a good crystalline silicate purity.

The present invention has been made in view of the above-mentioned state of the art, and aims to provide a method for producing a crystalline silicate which does not use an organic additive as a raw material and has no coexistence of by-products as in the above-mentioned method.

In the present invention, in the dehydrated form, (0.1-2.0) R _{2 / n} O ·
During _{[aM 2 O 3 · bAl 2 O} 3 ] · ySiO ₂ (above formula, R: 1 or more monovalent or divalent ion, n:
R valence, M: Fe + Co, Fe + V, Ni, Ru,
One or more element ions selected from the group consisting of La, Ce, Ti, V, Cr, Nb , and Bi, a + b = 1, a>
0, b> 0, y ≧ 12) and producing a crystalline silicate having a lattice spacing (α value) in powder X-ray diffraction shown in Table A, a silica source, alumina source, monovalent or divalent metal salt and M ₂ O _3: a slurry of aqueous raw material mixture comprising a water-soluble material based salts (M same as defined above) is prepared, this _{time, H 2 O / R 2 /} n the pH in the range of 7-9.5 when O ratio and a _{5~20 R 2 / n O / (} Al 2 O 3 + M 2 O 3) ratio of 5 to 20, H ₂
O / R2 _/ nO ratio is 20-300 and R2 _/ nO / (Al
_{2 O 3 + M 2 O 3} ) ratio of 11 to a pH in the case of 1-8
A method for producing a crystalline silicate, which is prepared in the range of 14 and maintained under hydrothermal synthesis conditions.

[Table 2]

Conventionally, when a crystalline silicate is produced using an organic substance such as tetrapropylammonium bromide, it has been produced starting from an aqueous mixture having the following molar composition. SiO ₂ / (Al ₂ O ₃ + M ₂ O ₃ ): 12-3000
(Preferably _{20~200) H 2 O / SiO 2} : 5~1000 ( preferably _{7~200) R 2 / n O /} SiO 2: 0.02~1.0 ( preferably 0.05 to 0.2 _{) H 2 O / R 2 /} n O: 5~1000 ( preferably 10-300) organic compound _{/ (Al 2 O 3 + M} 2 O 3): 1~100
(Preferably 5 to 50)

As in the present invention, when the organic compound is not added, the above molar composition does not apply to the synthesis of crystalline silicate with high purity, but the aqueous solution based on the added metal oxide (M ₂ O ₃ ) source is used. It has been found that the crystalline raw material salt works effectively as a crystallization accelerator, and the present invention has found that a predetermined crystalline silicate can be synthesized under the following molar composition conditions.

The molar composition of the reaction mixture is SiO ₂ / (Al ₂ O ₃ + M ₂ O ₃ ): 12 to 100
(Preferably 20 to 60) H ₂ O / SiO ₂ : 5 to 1000
(Preferably 7 to 200)

Further, the pH of the formed gel, ie, the gel
H in⁺(Hydrogen ion) concentration is an important factor._TwoO
/ R_{2 / n}O ratio is 5 to 20 and R_{2 / n}O / (Al_TwoO
_Three+ M_TwoO_Three) When preparing a slurry with a ratio of 5 to 20
PH ranges from 7 to 9.5 and H_TwoO / R_{2 / n}O ratio
Is 20 to 300 and R_{2 / n}O / (Al_TwoO_Three+ M _Two
O_Three) When the ratio is adjusted to 1 to 8, the pH is 11 to 14.
Must be prepared.

Further, the crystalline silicate of the present invention is synthesized by heating the above-mentioned raw material mixture at a temperature and for a time sufficient to produce the crystalline silicate. The hydrothermal synthesis temperature is 80 to 300 ° C., preferably It is in the range of 130 to 200 ° C, and the hydrothermal synthesis time is 0.5 to 14 days, preferably 1 to 10 days.

[0015]

The metal oxide added in the method of the present invention (M
It has been found that the metal ion of the water-soluble raw material salt based on ₂ O ₃ ) has the function of a central cation at the pore intersection, and exhibits an important function of promoting crystal growth. Metal ions of the water soluble material salts are Fe + Co, Fe + V, Ni, rare earth elements, Ti, V, Cr, Nb , Sb, B i.

Further, the above metal ions function as important catalytic active sites in the generated crystalline silicate,
Especially, the present invention crystalline silicates carrying the copper direct decomposition reaction of nitrogen oxides _{(2NO → N 2 + O 2} ), purification reaction of the exhaust gas (e.g. _{9NO + C 3 H 6 → 9} / 2N 2 · 3
(CO ₂ + 3H ₂ O) has been found to have high activity.

The water-soluble raw material salt based on the metal oxide to be added can be any of chloride, nitrate, sulfate, acetate and the like, and is not particularly limited. Hereinafter, the method for producing a crystalline silicate of the present invention will be described with reference to examples.

[0018]

【Example】

(Example 1) Sodium aluminate (Purity 85%, manufactured by Hayashi Junyaku Co., Ltd.) 1
98.1 g, caustic soda (manufactured by Hayashi Junyaku Co., Ltd.) 211.
7 g is dissolved in 4018 g of water to obtain a solution A. On the other hand, a silica sol solution (Nissan Chemical Snowtex O: SiO ₂
(20%) 4320 g of water was added to 9180 g, and 27 g of ferric chloride and 145 g of cobalt chloride were further dissolved in this aqueous solution to obtain a solution B.

Next, the solution A and the solution B are uniformly added to another container, neutralized, and mixed and stirred at a uniform pH (pH = 12.6) to form a gel. The gel was set in a stainless steel autoclave, and maintained at 160 ° C. for 72 hours under self-generated pressure to synthesize a crystalline silicate.

After completion of the reaction, the product was filtered and washed, and then dried at 120 ° C. As a result, crystalline silicate 1 was obtained, and as a result of powder X-ray diffraction, it was found to have the crystal pattern shown in Table A above.

(Example 2) Water glass No. 1 (manufactured by Tokuyama Soda, Si
5616 g of water (containing 37% of O ₂ ) was dissolved in 5429 g of water,
Obtain solution A. On the other hand, sodium chloride 2
62 g, aluminum sulfate 749 g, ferric chloride 22 g
And 15 g of cobalt chloride and 1700 g of concentrated hydrochloric acid were added and dissolved to obtain a solution B.

Next, the solution A and the solution B were uniformly added to another container and neutralized in the same manner as in Example 1, and mixed and stirred at a uniform pH (pH = 8.5) to form a gel. This gel was set in a stainless steel autoclave and 100
The crystalline silicate was synthesized by maintaining the pressure at 24 ° C. for 24 hours and at 170 ° C. for 48 hours under self-generated pressure.

As a result of powder X-ray diffraction, the crystalline silicate 2 was found to have the crystal pattern shown in Table A above.

Example 3 In Example 1, 42 g of lanthanum nitrate was added in place of ferric chloride and cobalt chloride, and the other processes were the same as in Example 1, except that crystalline silicate 3 was used.
I got

Similarly, 28 g of cerium nitrate, 26 g of titanium tetrachloride, 16 g of vanadium trichloride and 18 g of ferric chloride
g, niobium chloride 6 g, bismuth chloride 26 g, and chromium nitrate 38 g were added instead of ferric chloride and cobalt chloride, respectively.
5, 6, 7, and 8 were obtained.

All of these crystalline silicates had the diffraction patterns shown in Table A above as a result of powder X-ray diffraction.

Example 4 In Example 2, 6 g of ruthenium chloride and 26 g of nickel chloride were added in place of ferric chloride and cobalt chloride.
Crystalline silicates 9 and 10 were obtained in the same manner as described above.

As a result of powder X-ray diffraction of these crystalline silicates, they had the diffraction patterns shown in Table A above.

(Comparative Example) Crystalline silicates 11 and 12 were obtained in the same manner as in Examples 1 and 2 except that ferric chloride and cobalt chloride were not added and the organic substances were not added. Was.

As a result of powder X-ray diffraction of these crystalline silicates, it was found that the crystalline silicate 11 formed almost amorphous and the crystalline silicate 12 formed almost mordenite type crystal structure.

The above Examples 1 to 4 and Comparative Examples are summarized below.
It is shown in Table B.

[Table 3]

[0032]

As shown in Examples according to the present invention, by <br/> adding a water-soluble material salts based on specific metal oxide raw material of the crystalline silicate, without the addition of conventional organic and synthetic It has become possible to easily synthesize crystalline silicate, which has been impossible. The added metal ions effectively act as catalytically active species in the crystalline silicate, and the crystalline silicates 1 to 10 carrying copper directly decompose nitrogen oxides (2NO → N ₂ + O ₂ ) and purify exhaust gas. reaction _{(9NO + C 3 H 6 →} 9 / 2N 2 · 3CO 2 + 3H 2 O)
And the like.

──────────────────────────────────────────────────の Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C01B 33/20-39/54

Claims (1)

(57) [Claims] 1. A dehydrated form, expressed in terms of mole ratios of _{oxides, (0.1~2.0) R 2 / n} O · [aM ₂
O ₃ .bAl ₂ O ₃ ] .ySiO ₂ (in the above formula, R: 1
Species or higher monovalent or divalent ions, n: valence of R, M: Fe + Co, Fe + V, Ni, Ru, La, C
e, at least one element ion selected from the group consisting of Ti, V, Cr, Nb , and Bi, a + b = 1, a> 0, b>
0, y ≧ 12) and a crystalline silicate having a lattice spacing (α value) in powder X-ray diffraction shown in Table A, a silica source, an alumina source,
A slurry of an aqueous raw material mixture consisting of a monovalent or divalent metal salt and a water-soluble raw material salt based on M ₂ O ₃ (M: as defined above) is prepared, wherein the H ₂ O / R _{2 / n} O ratio is Is 5 to 2
0 a and _{R 2 / n O / (Al} 2 O 3 + M 2 O 3) ratio of 5
In the case of 20, the pH is set in the range of 7 to 9.5, and H ₂ O / R
_{The 2 / n} O ratio is 20-300 and R _{2 / n} O / (Al ₂ O ₃
+ M ₂ O ₃₎ ratio is adjusted to 11 to 14 range of pH in the case of 1-8, method for producing a crystalline silicate which is characterized in that retaining the hydrothermal synthesis conditions. [Table 1]