JPH08310810A - Production of high purity crystalline silicoalumino-phosphate - Google Patents

Abstract

PURPOSE: To selectively produce a cubic crystalline silicoalumino-phosphate. CONSTITUTION: In the process for producing the silicoalumino-phosphate by the use of an aluminum compound, a phosphorus compound, a silicon compound and an organic templating agent, each raw material compound in an amount of, Si:Al=0.18:1 to 0.2:1 and P:Al=0.76:1 to 0.81:1 (where, Si, Al and P mean respectively moles of silicon atom in the silicon compound, moles of aluminum atom in the aluminum compound and moles of phosphorus atom in the phosphorus compound) is used.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a crystalline silicoaluminophosphate (hereinafter referred to as SAP) having a chabazite structure, which is useful as various catalysts and adsorbents requiring heat resistance and hot water resistance.
O-34. ) Manufacturing method.

[0002]

2. Description of the Related Art As a method for producing SAPO-34, there are methods disclosed in Japanese Examined Patent Publication No. 3-201010, Japanese Unexamined Patent Publication No. 2-251246 and the like. Further, the present inventors previously found a method in which the reaction solvent was a solvent containing alcohol as a method for safely and inexpensively synthesizing SAPO-34 in a large amount, and filed as Japanese Patent Application No. 6-1748885. SAPO-34 obtained by these methods is a mixture of spherical crystals and cubic crystals. The spherical crystal has a silicon atom content of 1 to 3 mol%, and the cubic crystal has a content of 9 to 9 mol%.
13%. (Hereinafter, the former is called SAPO-34 (A) and the latter is called SAPO-34 (B).)

[0003]

When SAPO-34 obtained by the above method is used as it is, for example, as a carrier of a catalyst for removing nitrogen oxides, SA having a low silicon content is used.
Since PO-34 (A) has few active sites as zeolite, the desired catalytic activity may not be obtained in some cases. Therefore, it is desired to develop a method capable of efficiently producing SAPO-34 (B) having many active sites.

[0004]

The present inventors have completed the present invention as a result of intensive studies and improvements to solve the above problems.

That is, according to the present invention, (1) in the step of producing a crystalline silicoaluminophosphate using an aluminum compound, a phosphorus compound, a silicon compound and an organic templating agent, Si: Al = 0.18: 1 to 0.2: 1 P: Al = 0.76: 1 to 0.81: 1 (where Si, Al, and P are the amount of silicon primitive in the above silicon compound, the amount of aluminum atoms in the aluminum compound, and the phosphorus compound) The amount of the phosphorus atom of each of which is represented by the formula (1) is used. (2) A method for producing a crystalline silicoaluminophosphate characterized by using each raw material compound, (2) The aluminum compound is aluminum triisopropoxide, and the phosphorus compound Is orthophosphoric acid or metaphosphoric acid, and the organic templating agent is tetraethylammonium hydroxide. The method for producing a Norin salt.

Next, the present invention will be described. In the present invention, a mixture of a silicon compound, an aluminum compound, a phosphorus compound and an organic templating agent is hydrothermally synthesized. Examples of the silicon compound that can be used include known raw materials, specifically, fused silica, silica sol, silica gel, and silica alkoxide, with silica sol and silica gel being preferred. The silicon compound is used in an amount such that the ratio of the number of moles of silicon atoms contained in the silicon compound to the number of moles of aluminum atoms contained in the aluminum compound described below is 0.18: 1 to 0.2: 1. If the amount of silicon compound charged falls below this range, SA
When PO-34 (A) becomes present and the charged amount of the silicon compound is further reduced, SAPO-5 is produced or becomes amorphous. Further, if it exceeds this range, many undesired compositions exist or become amorphous.

Known compounds can be used as the aluminum compound. Preferably, the dispersion state of the aluminum compound is improved when the aluminum compound and the phosphorus compound are mixed, for example, pseudo-boehmite, aluminum trimethoxide, aluminum triethoxide, aluminum tri-2-butoxide, aluminum tri-t-butoxide. , Aluminum triisopropoxide, and aluminum alkoxides and aluminophosphates. Considering availability and controllability of reaction, aluminum triisopropoxide is particularly preferable among them.

Specific examples of phosphorus compounds that can be used include orthophosphoric acid, sodium metaphosphate, phosphorous acid,
Mention may be made of potassium dihydrogen phosphate, sodium dihydrogen phosphate, monoammonium phosphate, diphosphorus pentoxide and aluminophosphates, with orthophosphoric acid being particularly preferred. The phosphorus compound is used in an amount such that the ratio of the number of moles of phosphorus atoms contained in the phosphorus compound to the number of moles of aluminum atoms contained in the aluminum compound is 0.76: 1 to 0.81: 1. If the amount of the phosphorus compound charged is less than this range, many undesired compositions such as amorphous substances will be present, and if the amount is less, amorphous substances will be produced. Further, when the content is more than this range, the obtained composition forms undesired SAPO-5 or becomes amorphous.

The organic templating agent used in the present invention is deeply involved in determining the crystal structure of the target substance. The first specific example of the organic templating agent that can be used in the present invention
Listed in the table. These can be used alone or as a mixture of several kinds. The amount of the organic templating agent used is 1 mol of the above aluminum compound,
It is usually 0.03 mol to 1 mol, preferably 0.40 mol to 0.80 mol.

[0010]

[Table 1] Table 1 Tetramethylammonium ion, tetraethylammonium ion, tetrapropylammonium ion, tetrabutylammonium ion, di-n-propylamine, triethylamine, triethanolamine, piperidine, cyclohexylamine, N, N-diethylethanol Amine, dicyclohexylamine, N, N-dimethylethanolamine, choline, N, N'-dimethylpiperazine, 1,4-diazabicyclo- [2,2,2] octane, N-methyldiethanolamine, N-methylethanolamine, N -Methylpiperidine, 3-methylpiperidine, N-methylcyclohexylamine, 3-methylpyridine, 4-methylpyridine, quinuclidine, N,
N'-dimethyl-1,4-diazabicyclo- [2,2,
2] Octane ion, di-n-butylamine, neopentylamine, ethylenediamine, pyrrolidine, 2-imidazolidone

In Table 1, the term "ion" means a compound which produces these ions when dissolved in water. In the present invention, it is preferable to use tetramethylammonium hydroxide among these organic templating agents.

In obtaining the mixture, water can usually be used as a solvent. The amount of water used is usually 50 to 50 per 100 parts by weight of the total weight of the silicon compound, aluminum compound, phosphorus compound, and organic templating agent.
00 parts by weight, preferably 100 to 1500 parts by weight. Further, as a solvent, methanol, ethanol, n-,
Alcohols such as i-propyl alcohol may be used in combination with water. Alcohol is 0 for 100 parts by weight of water
~ 1000 parts by weight are used as needed. The alcohols may be distilled off by heating or the like if necessary after mixing the aluminum compound and the phosphorus compound, but they may be present in the reaction solution as they are without any problem. The solvent (water and optionally alcohols) is not particularly necessary when a part of the raw material compound is liquid (for example, when the phosphorus compound is orthophosphoric acid), but when there is a rapid heat generation, the above alcohol is used. Preference is given to using.

Further, water is contained in the phosphorus compound, silica compound and organic templating agent, and such water also functions as a solvent as it is. However, an excessive amount of water lowers the pH of the reaction solution and inhibits crystal growth and the like. In particular, it is not preferable to have an excessive amount of water when mixing the aluminum compound and the phosphorus compound.

In the present invention, the above components are uniformly mixed in a predetermined amount, but the aluminum compound and the phosphorus compound are mixed first. At this time, when rapidly mixed, heat is generated due to the reaction between the aluminum compound and the phosphorus compound, so depending on the reaction amount, in the case of 50 mmol scale,
The mixing time is preferably 10 seconds or more. The temperature at the time of mixing is preferably as low as possible, particularly preferably room temperature or lower.

Then, a silicon compound and an organic templating agent are mixed with the above mixture. In this case, the higher the pH, the better the result. That is, when the aluminum compound, the phosphorus compound, the silica compound, and the organic templating agent are mixed, it is preferable that the pH is 9 or more, and particularly pH 1
1 or more is preferable.

The mixture thus obtained is heated in a pressure vessel and hydrothermally synthesized under autogenous pressure. The heating temperature is usually 150 ° C or higher and 300 ° C or lower, and 200 ° C or higher and 300 ° C or higher.
C. or less is preferable. The crystals thus obtained are separated, washed with water and calcined to remove the organic templating agent, whereby the desired SAPO-34 (B) is obtained. The firing temperature at this time is preferably 400 ° C. or higher and 700 ° C. or lower.

[0017]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the following examples.

Example 1 9.3 g of 85 wt% orthophosphoric acid was weighed in a beaker,
40 ml of methanol was added thereto and stirred. Another beaker, 20.5 g of aluminum triisopropoxide 3N manufactured by Kanto Kagaku Co., was weighed, 20 ml of methanol was added thereto, the mixture was added to the above mixture, and stirring was continued.

After 3 hours, 30 g of the solvent in the beaker was removed using an oil bath at 90 ° C. Then water 20
ml was added and stirred, and 3.75 g of a silica sol 30% aqueous solution (CATALOID-SI-30 manufactured by Catalysts & Chemicals Industry Co., Ltd.) was added and the stirring was continued. After 30 minutes, 58.9 g of a 10% tetraethylammonium hydroxide solution manufactured by Wako Pure Chemical Industries, Ltd. was added. This solution was placed in a zirconia-coated stainless steel pressure vessel, and the autogenous pressure (23 kg / c) was set at 210 ° C.
The mixture was heated and stirred at m ² ) for 12 hours.

After completion of the reaction, the reaction mixture was rapidly cooled, and the solid reaction product in the container was recovered by centrifugation at 1500 rpm, pure water was further added and stirred, and the mixture was centrifuged at 1500 rpm. Pure water was added to the obtained solid, and the steps of stirring and centrifugation were performed 4 times. The product was dried and measured by X-ray diffraction (RIGAK
As a result of performing URINT-1100V), the diffraction peaks shown in Table 2 were obtained. When this crystal was observed by SEM, only SAPO-34 (B) was present.
Further, the composition of the crystal was analyzed by an X-ray microanalyzer, and Si: Al: P = 0.13:
The composition was 0.50: 0.40.

[0022]

[Table 2] Table 2 Peak No. 2θ d I / I ₀ × 100 1 9.44 9.36 77 2 12.78 6.9 14.2 14 3 13.98 6.33 12 4 15.92 5.56 51 5 17.86 4.96 19 6 18 .84 4.70 9 7 20.48 4.33 100 8 22.04 4.02 4 9 22.98 3.87 6 10 25.04 3.55 23 11 27.50 3.24 4 12 28.22 3.16 4 13 29.44 3.03 5 14 30.44 2.93 33 15 31.11 2.87 23 16 32.16 2.78 3 17 34.30 2.61 17 18 36.10 2. 49 5 19 38.64 2.33 2 20 39.56 2.284

In Table 2, θ: diffraction angle (degree) of Kα ray of Cu d: interplanar spacing (angstrom) I: intensity of each peak I ₀ : intensity of the strongest peak

Example 2 9.1 g of 85 wt% orthophosphoric acid was placed in a beaker, and 40 ml of primary methanol was added and stirred. 20.3 g of aluminum triisopropoxide was added little by little thereto, 20 ml of methanol was further added, and stirring was continued for 3 hours. Next, 35 g of the solvent was removed using an oil bath at 90 ° C., and 3.9 g of a 30 wt% aqueous solution of silica sol and 1
73.7 g of 0% tetraethylammonium hydroxide solution was added.

This solution was then placed in a zirconia-coated stainless steel pressure vessel and heated at 210 ° C. under autogenous pressure (20 kg / cm ² ) for 8 hours. After the reaction is completed, it is rapidly cooled, and the solid reaction product in the vessel is 1500 rpm.
Collected by centrifugation at 1,500 r
It was centrifuged at pm. Pure water was added to the obtained solid, and the steps of stirring and centrifugation were performed 4 times. The product was dried and subjected to X-ray diffraction measurement.

As a result, the diffraction peak was almost the same as in Example 1. Further, when this crystal was observed by SEM, only SAPO-34 (B) was present in the crystal.
Further, the composition of the crystal was analyzed by an X-ray microanalyzer, and Si: Al: P = 0.13:
The composition was 0.50: 0.40.

Comparative Example A beaker was charged with 10.2 g of 85 wt% orthophosphoric acid,
25 ml of methanol was added thereto and stirred. 10.2 g of aluminum triisopropoxide was added thereto little by little, and stirring was continued for 6 hours. And 1.5 g of silica sol and 29.4 g of 10% tetraethylammonium hydroxide solution.
Was added.

This solution was then placed in a zirconia-coated stainless steel pressure vessel and heated at 210 ° C. under autogenous pressure (20-21 kg / cm ² ) for 41 hours. After the reaction is heated, it is cooled rapidly, and the solid reaction product in the vessel is reduced to 1
It was recovered by centrifugation at 500 rpm, pure water was further added, and the mixture was centrifuged at 1500 rpm. This pure water was added, and the steps of stirring and centrifugation were performed 4 times. About this crystal S
When observed by EM, SAPO-34 (A) and SAPO
About −34 (B) was present in each half.

Further, when the composition of each of these crystals was analyzed by an X-ray microanalyzer, S
APO-34 (A) has Si: Al: P = 0.03: 0.
The composition was 63: 0.34, and SAPO-34 (B) had a composition of Si: Al: P = 0.10: 0.49: 0.42. Incidentally, SAPO-34 (A), SAPO-3
No. 4 (B) was difficult to separate because the particle size, specific gravity and the like were close to each other.

[0030]

According to the present invention, a large amount of SAPO-34 (B) can be manufactured at a low cost at a low cost without making a great change in the device.
Can be selectively synthesized. SA thus obtained
PO-34 (B) is useful as a catalyst carrier such as an adsorbent and a catalyst for reducing nitrogen oxides.

Claims (2)

[Claims] 1. In the step of producing a crystalline silicoaluminophosphate using an aluminum compound, a phosphorus compound, a silicon compound and an organic templating agent, Si: Al = 0.18: 1 to 0.2: 1 P : Al = 0.76: 1 to 0.81: 1 (where Si, Al, and P are the number of moles of silicon atoms in the silicon compound, the number of moles of aluminum atoms in the aluminum compound, and the number of phosphorus atoms in the phosphorus compound, respectively). Each of the raw material compounds is used in an amount such that the number of moles of the raw material compound). 2. The crystalline silicoaluminophosphate according to claim 1, wherein the aluminum compound is aluminum triisopropoxide, the phosphorus compound is orthophosphoric acid or metaphosphoric acid, and the organic templating agent is tetraethylammonium hydroxide. Manufacturing method.