JP2853318B2 - Crystalline copper silicate and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a crystalline copper silicate and a method for producing the same.

Since this crystalline copper silicate has adsorption properties and catalytic performances that cannot be obtained with conventional zeolites, it can be used as a molecular sieve, adsorbent, or as a catalyst component for denitration and hydrocarbon conversion reactions, as well as a copper ion sterilization ability. It is useful as a bactericidal substance that makes use of the above.

<Prior Art> Conventionally, as a method of incorporating a metal into a zeolite, ion exchange or loading by impregnation is known.

Furthermore, a method of allowing a metal to be present in a raw material for producing zeolite has recently become known. Copper silicate in which a copper compound is present in a zeolite production raw material is disclosed in JP-A-1-31.
Japanese Patent Application Laid-Open No. 9488 and JP-A-64-15142 disclose a structure having the structure of ZSM-5.

<Problems to be Solved by the Invention> However, by ion exchange, only an equimolar amount of copper or alkaline earth metal with alumina in zeolite could be taken. In addition, a large amount of metal can be taken in by supporting by impregnation or the like, but the taken-in metal tends to form aggregates as hydroxides or oxides, and copper and alkaline earth metals are highly Could not be dispersed.

In addition, the conventional method in which a copper compound is present in a raw material for producing zeolite can capture a large amount of metal, but the captured metal also easily forms aggregates as hydroxides or oxides. Could not be highly dispersed.

<Means and Actions for Solving the Problems> The present inventors have prepared a crystalline copper silicate having a structure similar to ZSM-5 and having a desired amount of copper and alkaline earth metal highly dispersed in the crystal. As a result of intensive studies for the purpose of manufacturing, the present invention has been achieved.

 Hereinafter, the present invention will be described in detail.

The novel substance of the present invention is represented by the following formula: aR ₂ O.bMO.cAl ₂ O ₃ .CuO.dSiO ₂ (where a, b, c, and d are 0 <b ≦ 10, 0 ≦ c ≦ 2 20 (c + 1) ≦ d ≦ 3000 0 ≦ a ≦ d / 40, where R is an organic mineralizer and M is an alkaline earth metal. A crystalline copper silicate having a powder X-ray diffraction pattern substantially including the lattice spacing shown in Table 1 in an unfired state, and comprising copper and alkaline earth It is a crystalline copper silicate produced in the presence of a metal. The crystalline copper silicate of the present invention incorporates copper and alkaline earth metal into the crystal during the crystallization step,
It is characterized by a high dispersion of copper and alkaline earth metals in the crystal. Further, the novel substance of the present invention
As can be determined from the composition, the presence of aluminum is not essential.

Table 1 Powder X-ray diffraction pattern spacing d (A) Peak intensity 11.19 ± 0.60 W 10.03 ± 0.50 W 3.86 ± 0.07 VS 3.83 ± 0.07 S 3.76 ± 0.07 M 3.72 ± 0.06 M 3.66 ± 0.06 W to M 3.45 ± 0.05 W 3.06 ± 0.04 W 2.99 ± 0.04 W (W, M, S, and VS in the table represent weak, medium, strong, and very strong, respectively) Hereinafter, the method for producing the crystalline copper silicate of the present invention will be described. explain.

A tetrapropylammonium compound; an alkaline earth metal source; a copper source; an aluminum source; a silicon source; a hydroxy ion source;
The following _{composition, SiO 2 / CuO 20~3000 MO /} CuO 0.05~10 Al 2 O 3 / CuO 0~2 OH - / SiO 2 0.04~0.40 H 2 O / SiO 2 15~100 TPA / SiO 2 0.02~1.0 (Where M represents an alkaline earth metal and TPA represents a tetrapropylammonium compound; the same shall apply hereinafter), and the reaction mixture is kept at a temperature of 90 ° C. to 230 ° C. for crystallization. It is mandatory.

As can be determined from the raw material composition, no alkali metal is used in the production method of the present invention. Conventionally, an alkali metal hydroxide, usually sodium hydroxide, has been used for the synthesis of a zeolite-like silicate. However, the present inventors have found that the use of an alkali metal hydroxide promotes the formation of amorphous copper silicate and localizes the copper. We have found a manufacturing method.

Accordingly, the tetrapropylammonium compound, alkaline earth metal source, copper source, aluminum source, silicon source, and hydroxy ion source used in the present invention are not particularly limited, but all need to contain no alkali metal.

For example, a tetrapropylammonium halide or hydroxide can be used as the tetrapropylammonium compound.

As the alkaline earth metal source, salts, oxides, hydroxides and the like containing these metals can be used, but it is desirable that the source is water-soluble in order to obtain a higher dispersion state. Preferred alkaline earth metal species are Sr and Ca.

As the silicon source, colloidal silica, amorphous silica, fumed silica, water glass from which alkali metals have been removed, and the like can be used.

As the aluminum source, salts, oxides, hydroxides and the like containing aluminum can be used, but the presence of the aluminum source is not essential, as can be judged from the raw material composition.

Hydroxy ions may be obtained by adding a hydroxide such as an alkaline earth metal or ammonium, or by adding an alkaline raw material as another raw material, for example, tetramethylammonium hydroxide as a tetrapropylammonium compound and ammonia as a silicon source. It is introduced by using colloidal silica or the like.

When a highly alkaline raw material such as tetrapropylammonium hydroxide is used, it is necessary to neutralize it with an acid such as sulfuric acid, phosphoric acid or hydrochloric acid in addition to the above raw materials in order to obtain suitable reaction conditions. It may be.

It is essential that the composition of the reaction mixture be the following composition shown in molar ratio.

_{SiO 2 / CuO 20~3000 MO / CuO} 0.05~10 Al 2 O 3 / CuO 0~2 OH - if _{/ SiO 2 0.04~0.40 H 2 O /} SiO 2 15~100 TPA / SiO 2 0.02~1.0 why, SiO _If the value of ₂ / CuO is less than 20, crystallization will be remarkably slow. On the other hand, when the value of SiO ₂ / CuO is 3000 or more, the crystallization proceeds, but the amount of Cu in the produced crystal becomes extremely small and substantially contains copper, so the crystalline copper of the present invention Silicates cannot be produced.

If the value of MO / CuO is less than 0.05, the produced crystals are substantially free of alkaline earth metals, so that the crystalline copper silicate of the present invention cannot be produced. If it is larger than 10, amorphous copper silicate is produced as a by-product.

When the value of OH ⁻ / SiO ₂ is smaller than 0.04, crystallization does not proceed, and when it is larger than 0.40, amorphous copper silicate is produced as a by-product.

If the value of H ₂ O / SiO ₂ is less than 15, a reaction mixture having a suitable viscosity cannot be obtained. If the value is more than 100, the desired product can be obtained, but the yield is small and the efficiency is low.

If the value of TPA / SiO ₂ is less than 0.02, silicate minerals are by-produced. If the value is more than 1.0, the desired product can be obtained, but it is not economical.

If the reaction mixture is non-uniform, impurities may be by-produced. Therefore, these raw materials are preferably added with stirring, and the final reaction mixture is preferably stirred until it is substantially homogeneous.

The final reaction mixture thus obtained is crystallized using a stainless steel sealed pressure-resistant vessel lined with an inert plastic material such as, for example, polytetrafluoroethylene, in order to prevent contamination of impurities. The crystallization is preferably carried out by maintaining the temperature between 90 ° C. and 230 ° C. under autogenous pressure. At temperatures lower than 90 ° C, crystallization takes a considerable time, and at temperatures higher than 230 ° C, silicate minerals may be by-produced. Usually, the crystalline copper silicate of the present invention can be obtained by placing at this temperature for about 2 hours to about 200 hours.

The product is recovered by a conventional separation method such as filtration or centrifugation.

X-ray diffraction of the product herein is performed by a Philips powder X-ray diffractometer PW1700. The source is CuK-α
Using a line, using a variable divergence slit,
The measurement is performed with the X-ray irradiation area on the measurement sample kept constant.

The crystalline copper silicate of the present invention produced as described above contains a tetrapropylammonium ion or a compound thereof in the pores. If necessary, the crystalline copper silicate of the present invention containing this organic substance may be heated to 350 ° C. to 6 ° C.
By firing at 00 ° C., the organic matter can be decomposed and removed. The powder X-ray diffraction pattern of the crystalline copper silicate of the present invention is:
This firing does not essentially change.

<Effect of the Invention> The crystalline copper silicate of the present invention incorporates copper and alkaline earth metal into the crystal during the crystallization step, and copper and alkaline earth metal are highly dispersed in the crystal. Highly dispersing the metal increases the number of active sites per amount of metal and can result in a more active catalyst or adsorbent.

The crystalline copper silicate of the present invention can be effectively used as various adsorptive separation agents by controlling the pore size and adsorption characteristics by ion exchange operation after removing organic substances.

In addition, it can be used as a catalyst for various reactions such as removal of hydrogen and oxygen in gas, denitration, and hydrocarbon addition reaction by utilizing the catalytic ability of copper ions.

Furthermore, it can be used as an antibacterial substance by adding it to food packaging materials, etc., making use of the sterilizing ability of copper ions.

<Examples> In order to more specifically describe the present invention, examples will be shown below, but the present invention is not limited to the following examples.

Example 1 Amorphous silica (NIPSIL VN-3 SiO2 8 manufactured by Nippon Silica Co., Ltd.)
7.7 wt%, Al2O3 0.5 wt%), copper acetate monohydrate, strontium chloride hexahydrate, tetrapropylammonium hydroxide aqueous solution (10 wt%), and water are mixed to prepare a reaction mixture having the following molar composition. did.

_{SiO 2 / CuO 70 SrO / CuO} 3.50 Al 2 O 3 / CuO 0.24 OH - a _{/ SiO 2 0.10 H 2 O /} SiO 2 50 TPA / SiO 2 0.10 The Hatsuno mixture was sealed in an autoclave, with constant stirring The mixture was heated to 170 ° C. under autogenous pressure and maintained at this temperature for 64 hours to obtain a crystalline product. After filtration and washing with water,
Dried at 0 ° C.

The product had the following molar composition on a dry basis by chemical analysis.

1.91 (TPA) ₂ O · 1.93SrO · CuO · 0.25Al ₂ O ₃ · 90.4SiO ₂ This product was a crystalline copper silicate of the present invention having the powder X-ray diffraction pattern shown in Table 2.

Observation of this product with a scanning electron microscope revealed that the precipitation of foreign matter on the crystal surface was very small, as shown in FIG.
Copper was incorporated into the crystal.

Example 2 A reaction mixture having the following molar composition was prepared in the same manner as in Example 1 except that calcium chloride dihydrate was used instead of strontium chloride hexahydrate.

_{SiO 2 / CuO 70 CaO / CuO} 3.50 Al 2 O 3 / CuO 0.24 OH - / the _{SiO 2 0.08 H 2 O / SiO} 2 50 TPA / SiO 2 0.08 The reaction mixture was sealed in an autoclave, the constant stirring under autogenous pressure Heat to 170 ° C. and hold at this temperature for 64 hours to obtain a crystalline product. After filtration and washing with water,
Dried at 0 ° C.

The product had the following molar composition on a dry basis by chemical analysis.

1.90 (TPA) ₂ O · 2.02CaO · CuO · 0.24Al ₂ O ₃ · 90.6SiO ₂ This product was a crystalline copper silicate of the present invention having the powder X-ray diffraction pattern shown in Table 3.

When this product was observed with a scanning electron microscope, the deposition of foreign matter on the crystal surface was very small as shown in FIG.
Copper was incorporated into the crystal.

Example 3 In the same manner as in Example 1, a reaction mixture having the following molar composition was prepared.

_{SiO 2 / CuO 40 SrO / CuO} 0.10 Al 2 O 3 / CuO 0.13 OH - / the _{SiO 2 0.20 H 2 O / SiO} 2 50 TPA / SiO 2 0.20 The reaction mixture was sealed in an autoclave, the constant stirring under autogenous pressure Heat to 130 ° C. and hold at this temperature for 90 hours to obtain a crystalline product. After filtration and washing with water,
Dried at 0 ° C.

The product was found to have the following molar composition on a dry basis by compound analysis.

1.03 (TPA) ₂ O.0.08 SrO.CuO.0.14Al ₂ O ₃ .50.3SiO ₂ This product was a crystalline copper silicate of the present invention having the powder X-ray diffraction pattern shown in Table 4.

When this product was observed with a scanning electron microscope, as shown in FIG.
Copper was incorporated into the crystal.

Example 4 In the same manner as in Example 1, a reaction mixture having the following molar composition was prepared.

_{SiO 2 / CuO 40 SrO / CuO} 2.0 Al 2 O 3 / Cu 0.13 OH - / the _{SiO 2 0.10 H 2 O / SiO} 2 70 TPA / SiO 2 0.10 The reaction mixture was adhered to the autoclave, the constant stirring under autogenous pressure Heat to 170 ° C. and hold at this temperature for 48 hours to obtain a crystalline product. After filtration and washing with water,
Dried at 0 ° C.

The product had the following molar composition on a dry basis by chemical analysis.

0.85 (TPA) ₂ O · 1.65SrO · CuO · 0.14Al ₂ O ₃ · 40.3SiO ₂ This product was the crystalline copper silicate of the present invention having the powder X-ray diffraction pattern shown in Table 5.

When this product was observed with a scanning electron microscope, the deposition of foreign matter on the crystal surface was very small as shown in FIG.
Copper was incorporated into the crystal.

Comparative Example 1 Amorphous silica (NIPSIL VN-3 SiO2 8 manufactured by Nippon Silica Co., Ltd.)
7.7 wt%, Al 2 O 3 0.5 wt%), copper acetate monohydrate, sodium hydroxide, tetrapropyl ammonium bromide, and water were mixed to prepare a reaction mixture having the following molar composition.

_{SiO 2 / CuO 40 Na 2 O} / CuO 2.0 Al 2 O 3 / CuO 0.13 OH - / the _{SiO 2 0.35 H 2 O / SiO} 2 70 TPA / SiO 2 0.10 The reaction mixture was sealed in an autoclave, with constant stirring The mixture was heated to 170 ° C. under autogenous pressure and maintained at this temperature for 48 hours to obtain a crystalline product. After filtration and washing with water,
Dried at 0 ° C.

The product had the following molar composition on a dry basis by chemical analysis.

0.85 (TPA) ₂ O ・ 0.31Na ₂ O ・ CuO ・ 0.14Al ₂ O ₃・ 40.3SiO ₂ The product was observed with a scanning electron microscope. As shown in FIG. Had adhered.

Comparative Example 2 Sr was exchanged for a cation by a normal ion exchange operation.
ZSM-5 type zeolite having a SiO ₂ / Al ₂ O ₃ ratio of 251 was added to a 1.5% aqueous solution of copper acetate monohydrate to form a 10 wt% slurry. 5% aqueous ammonia was added to the slurry to adjust the pH of the slurry to 8.5. After stirring this overnight, it was washed with filtered water and copper was supported on zeolite.

According to the chemical analysis, the copper-supported zeolite obtained by the precipitation method had the following molar composition on an anhydrous basis.

The _{0.002SrO · CuO · 0.004Al 2 O 3} · 42.3SiO 2 The product was observed with a scanning electron production microscope,
As shown in FIG. 6, aggregates considered to be copper oxide or copper hydroxide were present on the surface of the zeolite crystal.

[Brief description of the drawings]

FIGS. 1, 2, 3, 4, 5, and 6 are scanning electron micrographs showing the crystal structures of the products of Examples 1, 2, 3, 4, and Comparative Examples 1 and 2, respectively.

Claims (2)

(57) [Claims] 1. An oxide represented by the molar ratio of aR ₂ O.bMO.cAl ₂ O ₃ .CuO.dSiO ₂ (where a, b, c and d are 0 <b ≦ 10, 0 ≦ c ≦ 2 20 (c + 1) ≦ d ≦ 3000 0 ≦ a ≦ d / 40, R represents an organic mineralizer, and M represents an alkaline earth metal.) A crystalline copper silicate having a powder X-ray diffraction pattern including the lattice spacing shown in Table 1 substantially in an unfired state, and containing copper and an alkaline earth metal Crystalline copper silicate produced in the presence. Table 1 Powder X-ray diffraction pattern Lattice spacing d (A) Peak intensity 11.19 ± 0.60 W 10.03 ± 0.50 W 3.86 ± 0.07 VS 3.83 ± 0.07 S 3.76 ± 0.07 M 3.72 ± 0.06 M 3.66 ± 0.06 W to M 3.45 ± 0.05 W 3.06 ± 0.04 W 2.99 ± 0.04 W (W, M, S, and VS in the table represent weak, medium, strong, and very strong, respectively) 2. A tetrapropyl ammonium compound; an alkaline earth metal source; a copper source; an aluminum source; a silicon source; a hydroxy ion source; _{2 / CuO 20~3000 MO / CuO 0.05~10} Al 2 O 3 / CuO 0~2 OH - / SiO 2 0.04~0.40 H 2 O / SiO 2 15~100 TPA / SiO 2 0.02~1.0 ( although, M is Wherein an alkaline earth metal and TPA represent a tetrapropylammonium compound), and the reaction mixture is maintained at a temperature of from 90 ° C. to 230 ° C. The method for producing a crystalline copper silicate according to the above item.