JPH0339008B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel crystalline iron silicate fired body having a three-dimensional network structure in which (SiO ₂ )(FeO ₂ ) ⁻ shares oxygen and a method for producing the same. To be more specific, (0, 2, 0), (0,
The present invention relates to a crystalline iron silicate fired body similar to ZSM-5 with particularly developed 4,0) planes and its production. Crystalline aluminosilicate containing (AlO ₂ ) ^- instead of (FeO ₂ ) ^- is called zeolite, and it is also produced naturally as a mineral, but currently there are only those with the same crystal structure as natural products, and Many substances classified as zeolites have been synthesized, although they are not produced in the world. These zeolites have a certain crystal structure with many voids and tunnels within the structure, and therefore have the function of adsorbing molecules of a certain size but excluding molecules larger than that, and are also called molecular sieves. be done. Pores due to voids or tunnels are determined by the form in which (SiO ₂ ) and (AlO ₂ ) ^- in the crystal structure bond by covalently oxygen. The electronegative nature of aluminum-containing tetrahedra is usually kept electroneutral by alkali metal ions, especially sodium and potassium. Usually, to produce crystalline aluminosilicate, SiO ₂ , Al ₂ O ₃ , alkali metal ion sources and water are mixed in the desired proportions under basic conditions, and then subjected to a hydrothermal reaction under normal or elevated pressure. A method is being taken to deal with it. There is also a method of using organic nitrogen compounds or organic phosphorous compounds as bases, and various crystalline aluminosilicates with various ion exchange abilities, adsorption abilities, and catalytic actions have been synthesized using these methods, and in recent years, they have been used to create energy, resources, and the environment. As one of the most important materials involved, it has become of great interest worldwide, and much research is being conducted on it. Especially by Mobil Oil Co.
ZSM zeolite is a crystalline aluminosilicate synthesized using tetraalkyl compounds, tetraalkylphosphonium compounds, ethylenediamine, choline, etc., and its unique adsorption ability and catalytic activity are attracting attention. Among them, ZSM-5 is 5
Because it has a medium pore size of ~6〓,
Straight-chain hydrocarbons and slightly branched hydrocarbons are adsorbed, but highly branched hydrocarbons are not adsorbed, and are suitable for catalytic dewaxing, cracking, isomerization,
It has outstanding performance as a catalyst for alkylation, polymerization and especially for the production of gasoline from methanol. As a result of intensive studies on the synthesis of new zeolites containing iron, the present inventors have found that, in particular, regarding the synthesis of crystalline iron silicate, SiO ₂ , Fe ₂ O ₃ , alkali metal ion sources, water and at least one (0,2,0), (0,4,
0) We have discovered that a crystalline iron silicate similar to ZSM-5 with particularly developed faces can be synthesized, and that this crystal face can be developed to any ratio by changing the amount of Sr compound added, and we have arrived at the present invention. . That is, according to the present invention, the molar ratio of S ₁ O ₂ and Fe ₂ O ₃ is 15 or more, and the powder X-ray diffraction pattern shown in Table 1 of the main text is (0, 2, 0).
A crystalline iron silicate fired body in which the (0,4,0) plane is particularly developed is provided. All of the powder X-ray diffraction patterns in the present invention were obtained according to a conventional method by irradiating copper with K-alpha rays. The fired product of the crystalline iron silicate of the present invention exhibits the X-ray diffraction pattern shown in Table 1 above, but no fired product has been known to exhibit such an X-ray diffraction pattern. The pattern shown in Table 1 is
Ger.Offen.2831611, JP-A-56-22623, JP-A-56
-26822, JP-A-56-96719, etc., it is very similar to the pattern of crystalline iron silicate. However, in general, crystalline iron silicate does not show peaks as strong as those of the present invention at around 8.8 degrees and around 17.8 degrees in 2θ. That is, compared to the conventional crystalline iron silicate, the product of the present invention has 2θ=
(0,2,0) plane giving a peak around 8.8 degrees and (0''4, giving a peak around 2θ=17.8 degrees)
0) A new zeolite with particularly developed surfaces. Next, a method for producing crystalline iron silicate according to the present invention will be described. As the SiO ₂ source, silica gel, silica sol, and silica can be used, and silica sol is preferably used. As the Fe ₂ O ₃ source, ferric nitrate, ferric sulfate, ferric chloride, etc. are used. As the alkali metal ion source, sodium hydroxide, potassium hydroxide, etc. are used. The various tetraalkylammonium compounds are preferably hydroxides and halides, and tetraalkylammonium bromide is particularly preferred. As the Sr compound, acetate and chloride can be used, and acetate is particularly preferred. These raw material compounds are mixed and subjected to a hydrothermal reaction treatment, and their composition is preferably in the following proportions. Note that any mixing method may be used as long as the mixture is mixed homogeneously so that the composition of the mixture falls within a predetermined range. SiO ₂ /Fe ₂ O ₃ (mole ratio): 15 or more OH ^- /SiO ₂ (mole ratio): 0.07 to 0.3 H ₂ O / SiO ₂ (mole ratio): 30 to 70 R ₄ N ⁺ /SiO ₂ (mole ratio): 0.08 to 0.16 Sr/Fe (molar ratio): 0.05 to 5 where OH ^- indicates the amount of hydroxyl ions in the mixture,
Corresponds to the amount of alkali metal ions. To adjust this value, an alkali metal hydroxide, an alkali metal oxide, etc. are used. R ₄ N ⁺ indicates the amount of tetraalkylammonium ion in the mixture. use here
By changing the amount of Sr compound, (0,2,0) and (0,4,0) planes can be developed at any ratio in crystalline iron silicate having the X-ray diffraction pattern shown in Table 1. be able to. An aqueous gel mixture with such a component composition is held under the conditions of temperature, pressure, and time under which normal crystalline iron silicate is produced to cause a hydrothermal reaction, and the resulting crystalline iron silicate is then calcined. In this way, the desired crystalline iron silicate fired body is obtained. That is, the aqueous gel mixture is heated at a temperature of 90 to 200°C, preferably 95 to 170°C, under reflux under normal pressure or in a closed container under autogenous pressure for 20 to 200°C.
Heat and stir for an hour. The reaction mixture is separated into a solid and an aqueous solution by sifting or centrifugation. The solid is further washed with water to remove excess ionic substances, and then dried to become crystalline iron silicate containing a tetraalkyl compound. This is carried out in air at 300-900℃, preferably
By firing at a temperature of 400 to 700°C for 1 to 100 hours, crystalline iron silicate containing no organic compounds is obtained. The crystalline iron silicate according to the present invention is directly
Alternatively, the alkali metal ions contained in advance as cations are exchanged with other cations using a known method to perform Fischer-Tropschule synthesis.
It can be used as a catalyst for methanol conversion reactions, decomposition, polymerization, alkylation, etc. Next, the present invention will be explained in detail with reference to examples, but the present invention is not limited thereto unless it exceeds the gist thereof. Examples 1 to 5 Example 1 will be explained. Colloidal silica Cataloid-SI-30 60g manufactured by Catalysts Kasei Co., Ltd., Nitric acid 2
4.92 g of iron nonahydrate, 5.90 g of potassium hydroxide, 7.82 g of tetra-n-propylammonium bromide and 6.54 g of strontium acetate 1/2 hydrate were uniformly mixed with 180 g of water to obtain an aqueous gel mixture; The mixture was heated and stirred at 160° C. for 16 hours under autogenous pressure in a closed container.
Separating solids from the reaction mixture by centrifugation;
Rinse thoroughly with water until all ionic substances are removed, then
It was dried at 100°C and further calcined at 500°C for 15 hours to obtain the desired crystalline iron silicate. The X-ray diffraction pattern of the product thus obtained is shown in Table 2 and FIG. Further, the specific surface area of this product measured by the BET method was 353 m ² /g. Methods for preparing crystalline iron silicate with varying amounts of other Sr compounds are summarized in Table 3. The X-ray diffraction pattern of the obtained product is
It was basically the same as shown in Table 2 and FIG. Example 6 7 g of the crystalline iron silicate obtained in Example 1 was
The suspension was suspended in 70 ml of 0.6N aqueous hydrochloric acid solution and treated at room temperature for 24 hours with stirring. Thereafter, the filtered solid material was washed with distilled water until no chlorine ions were detected, dried at 100°C for 5 hours, and further calcined in air at 500°C for 10 hours. This was compressed into tablets at a pressure of 400 Kg/cm ² , and then pulverized into 10 to 20 meshes. 2 ml of the tablet was filled into a reaction tube with an inner diameter of 10 mm. Liquid methanol is sent to the vaporizer at a rate of 4 ml/hr, where
It is mixed with argon gas sent at 45ml/min and guided into the reaction tube, and the temperature is increased from 320℃ to 600℃ at 15℃/min.
The reaction was carried out by raising the temperature at a rate of . Analysis of the product was performed using a gas chromatograph. Methanol conversion rate at reaction temperature 530℃ is 82.1%
So, the selectivity to hydrocarbons is calculated based on carbon.
It was 48.4%. Example 7 The crystalline iron silicate obtained in Example 5 was
The tablets were compressed at 400 kg/cm ² , and then 10 ml of 15 to 30 meshes were filled into a reaction tube with an inner diameter of 20 mm. Treat with hydrogen at a rate of 100 ml/min at 400°C for 15 hours, then switch the hydrogen to a mixed gas of carbon monoxide and hydrogen (molar ratio 1:1), LHSV=
The reaction was carried out at 450° C. for 2000 hr ⁻¹ . Analysis of the product was performed using a gas chromatograph. The CO conversion rate was 9.4%, and the selectivity to ethylene and propylene excluding CO ₂ was 28.8% on a carbon basis. Comparative Examples 1 to 3 Comparative Example 1 in which strontium acetate was not added, Comparative Example 2 in which calcium acetate was added in place of strontium acetate, and Comparative Example 3 in which potassium chloride was added in place of strontium acetate. It is shown in Table 4. The X-ray diffraction pattern of the crystalline iron silicate shown in Comparative Example 3 is shown in FIG. The other X-ray diffraction patterns were identical to those shown in FIG. From these results, in the preparation of crystalline iron silicate, by adding Sr compounds (other alkaline earth metal compounds and alkali metal compounds are ineffective), the peak around 2θ = 8.8° can be reduced to (0, 2, 0).
gives a peak near the plane and 2θ=17.8° (0,
It was found that the 4,0) plane can be developed to any desired ratio. Table 1 d (Å) Relative strength (100I/Io) 11.20±0.1 M 10.06±0.1 VS 7.49±0.05 VW 6.70±0.05 VW 6.37±0.05 VW 5.98±0.05 W 5.72±0.05 W 5.57±0.05 W 5.38±0. 05 VW 5.14±0.05 VW 4.98±0.05 M 4.62±0.05 VW 4.37±0.05 VW 4.27±0.05 W 4.09±0.05 VW 4.00±0.05 W 3.85±0.02 S 3.81±0.02 VS 3.75±0.02 M 3.7 2±0.02 M 3.64±0.05 W 3.53± 0.05 W 3.45±0.05 W 3.35±0.05 W 3.31±0.02 W 3.25±0.02 VW 3.05±0.02 W 2.99±0.02 W 2.96±0.02 W 2.86±0.05 VW 2.78±0.05 VW 2.73±0.0 5 VW 2.61±0.05 VW 2.51±0.05 VW 2.49±0.05 W 2.40±0.05 VW (VW: 0-5, W: 5-20, M: 20-
40, S: 40-60, VS: 60-100) Table 2 d (Å) Relative intensity (100I/Io) 11220 22 10069 100 7496 2 6741 3 6366 3 5990 14 5724 12 5569 6 5389 2 5146 2 4978 21 4635 2 4355 3 4266 8 4089 5 4000 5 3847 53 3814 69 3751 33 3718 21 3645 6 3539 6 3451 6 3348 6 3308 11 3246 3 3046 6 2986 7 2957 5 2867 2 2777 3 2738 3 2612 2 2518 3 2486 6 2411 2

【table】

【table】

【table】 [Brief explanation of drawings]

FIG. 1 is a powder X-ray diffraction diagram of the crystalline iron silicate of the present invention. FIG. 2 is a powder X-ray diffraction diagram of crystalline iron silicate synthesized by adding potassium chloride instead of strontium acetate.

Claims (1)

[Claims] 1. (0,2,0), (0,4) having a molar ratio of SiO ₂ and Fe ₂ O ₃ of 15 or more and having a powder , 0) Crystalline iron silicate fired body with particularly developed surfaces. 2 SiO ₂ , Fe ₂ O ₃ , alkali metal ion sources, Sr compound, water and at least one tetraalkyl ion source, and the composition expressed in molar ratio is SiO ₂ /Fe ₂ O ₃ ( molar ratio): 15 or more OH ^- /SiO ₂ (molar ratio): 0.07 to 0.3 H ₂ O / SiO ₂ (molar ratio): 30 to 70 R ₄ N ⁺ /SiO ₂ (molar ratio): 0.08 to 0.16 Sr / Crystallize the ^aqueous gel mixture with ^Fe (molar ratio): _0.05-5 . It is characterized by being subjected to a hydrothermal reaction under conditions that produce iron silicate, has a molar ratio of SiO ₂ and Fe ₂ O ₃ of 15 or more, and has a powder X-ray diffraction pattern shown in Table 1 of the main text. (0,2,0),
A method for producing a fired crystalline iron silicate body with particularly developed (0,4,0) planes.