JP2697033B2 - Large crystal mordenite-like zeolite having hexagonal columnar crystal shape and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a mordenite-like zeolite having a hexagonal columnar crystal shape, particularly to a zeolite having a large crystal and a method for producing them.

Monodenite-like zeolites having a hexagonal columnar crystal shape, particularly those having large crystals, can be effectively used as a catalyst, a catalyst carrier, or an adsorbent.

<Prior Art> Mordenite-type zeolites used for catalysts, adsorbents, and the like are usually small crystals having a plate shape of 1 to 5 μm or a quadrangular prism shape of 2 μm or less on a side. Forming particles.

Generally, as a method for synthesizing a zeolite having a large crystal, a method of performing crystallization for a long time in a static state has been known.

However, industrially, crystallization for a long time is inefficient, and crystallization under standing may lead to non-uniform product quality and by-product impurities.

<Problems to be Solved by the Invention> When zeolite is used as a catalyst or an adsorbent, its performance is greatly affected by its crystal shape, crystal size, and the like.

The present invention relates to a crystalline mordenite-like zeolite which can be effectively used as a catalyst, a catalyst carrier, an adsorbent, etc., having a novel crystal shape, a large crystal among them, and a method for industrially efficiently producing them. Is provided.

<Means for Solving the Problems> The novel substance of the present invention is a zeolite having a hexagonal columnar crystal shape and having a powder X-ray diffraction pattern shown in Table 1, and a zeolite having a crystal length of 20. It extends to ~ 50μ.

Table 1 X-ray powder diffraction pattern d (A) Relative intensity (%) 13.49 ± 0.88 M 9.03 ± 0.38 VS 6.56 ± 0.21 M 6.37 ± 0.20 W 5.78 ± 0.15 W to M 5.51 ± 0.14 M 3.98 ± 0.07 M 3.46 ± 0.05 M 3.38 ± 0.05 M 3.22 ± 0.05 M 3.20 ± 0.05 M (W, M, and VS in the table represent weak, medium, and very strong, respectively.) The production methods of these new substances will be described below.

Except for using a specific and specific amount of polyethylene glycol, the zeolite of the present invention can be produced by employing conventionally known production conditions for mordenite-type zeolite. That is, the molar composition _{SiO 2 / Al 2 O 3 10~200} (Na and / or _{K) 2 O / SiO 2 0.05~1.0} H 2 O / SiO 2 5~50 PEG / SiO 2 0.1~1.0 (PEG has an average By holding a reaction mixture consisting of polyethylene glycol having a molecular weight of 400 or less at 100 to 200 ° C. for 5 to 100 hours, the above-mentioned zeolite is easily formed.

Use of polyethylene glycol having an average molecular weight of more than 400 is not preferable in terms of operation because it has a high viscosity at room temperature or is in a solid state.

If the amount of polyethylene glycol is less than 10% of the number of moles of silica, the large crystalline mordenite-like zeolite having a hexagonal columnar crystal shape of the present invention cannot be obtained. If the amount of addition is more than 100% of the number of moles of silica,
Although the zeolite having a hexagonal columnar crystal shape of the present invention can be obtained, the yield is reduced and the efficiency is inefficient.

Raw materials for silica and alumina in the reaction mixture are not particularly limited, and raw materials conventionally used for the production of zeolite, ie, silica sources, include water glass, amorphous silica, colloidal silica, sodium silicate, and fumed silica. As alumina sources such as silica, sodium aluminate,
Alumina sol, aluminum hydroxide, aluminum oxide, aluminum sulfate and the like can be used. However, the crystal size of the product differs depending on the nature of the raw material used, particularly the raw material serving as the silica source. That is, when a silica source containing high molecular weight silica such as amorphous silica or diatomaceous earth is used, a relatively small crystal is obtained, and silica containing lower molecular weight silica such as water glass or colloidal silica is used. The use of a source results in a crystal consisting of 20 to 50 microns.

A large crystalline mordenite-like zeolite having a hexagonal columnar crystal shape can be produced even when stirring the reaction mixture during crystallization.

The zeolite having a hexagonal columnar crystal shape of the present invention,
It is similar to mordenite, but has the characteristic powder X-ray diffraction patterns shown in Table 1. In other words, compared to ordinary mordenite-type zeolite, the (200) plane attributed to diffraction lines near the lattice spacing of 9.03A develops, and the diffraction intensity attributed to the other planes is reduced to (200) plane. Less than half the assigned diffraction intensity.

<Effect of the Invention> Normally, the mordenite-type zeolite is obtained in the form of a secondary aggregate in which small crystals of 1 to 5 μm in a plate shape or a rectangular column having a side of 2 μm or less adhere to each other. However, the novel hexagonal columnar zeolite of the present invention has a
It can have a large crystal length of ~ 50μ and can be effectively used as a catalyst with excellent selectivity or as an adsorbent.

When zeolite is used as a catalyst or an adsorbent, its performance, thermal stability, life, and the like are greatly affected by the size of the crystals. In general, the larger the crystal,
It is known that its selectivity is excellent.

Further, according to the method of the present invention, the reaction mixture has an average molecular weight of
Up to 400 polyethylene glycols in the reaction mixture
By adding 10% to 100% of the number of moles of iO ₂ and crystallizing, zeolite that can be effectively used as a catalyst, an adsorbent, etc. can be industrially produced by the crystallization time of ordinary mordenite zeolite. It has become possible to manufacture efficiently.

Generally, as-synthesized zeolites contain the alkali metal ions used during the synthesis. This alkali metal ion can be exchanged for another cation by an ion exchange operation.

The zeolite obtained by the method of the present invention controls pore size and adsorption characteristics by this ion exchange operation,
It can be effectively used as various adsorption separation agents.

Further, after ion-exchange with an aqueous solution of an ammonium salt such as ammonium hydroxide, ammonium sulfate, or ammonium nitrate, the mixture is converted into an ammonium type, and then 400 to 700 ° C.
Ammonia is removed by calcining to obtain a hydrogen type having a high catalytic activity, which can be used as a solid acid catalyst.

Furthermore, a desired catalytically active component such as platinum can be introduced by ion exchange or loading, and used as a catalyst for various reactions such as a hydrocarbon conversion reaction.

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

Example 1 Water glass (SiO ₂ = 29.30 wt%, Na ₂ O = 9.35 wt%, Al ₂ O _{3
= 0.016wt%, H 2 O =} 61.334wt%), sodium aluminate _{(Al 2 O 3 = 18.80wt%} , Na 2 O = 19.16wt%, H 2 O = 62.04wt
%), Polyethylene glycol with an average molecular weight of 300 (PE
G), sulfuric acid (95%), and pure water were mixed to prepare a reaction mixture having the following composition.

SiO ₂ / Al ₂ O ₃ 50 Na ₂ O / SiO ₂ 0.2 H ₂ O / SiO ₂ 30 PEG / SiO ₂ 0.3 The reaction mixture is sealed in an autoclave, heated to 160 ° C. under natural pressure and the temperature is raised for 48 hours. Retention gave a crystalline product. This was filtered, washed with water and dried at 110 ° C.

The product was a mordenite-like zeolite having the powder X-ray diffraction pattern shown in Table 2.

This product was hexagonal and had a large crystal diameter of 30 to 50 μm, as shown in the scanning electron microscope image shown in FIG.

Table 2 d (A) Relative strength (%) 13.55 49 10.22 10 9.05 100 6.57 38 6.39 14 6.04 6 5.79 16 4.85 2 4.52 22 4.23 2 4.14 2 3.99 35 3.83 7 3.76 5 3.62 2 3.57 2 3.53 3 3.47 34 3.41 10 3.39 24 3.29 2 3.22 25 3.20 17 3.15 2 3.10 2 2.94 3 2.89 8 2.70 2 2.64 1 2.56 2 2.52 4 2.45 2 Example 2 Except that polyethylene glycol having an average molecular weight of 400 was used, A reaction mixture having the following composition was prepared.

SiO ₂ / Al ₂ O ₃ 50 Na ₂ O / SiO ₂ 0.3 H ₂ O / SiO ₂ 30 PEG / SiO ₂ 0.3 The reaction mixture is sealed in an autoclave, heated to 160 ° C. under natural pressure and the temperature is raised for 48 hours. Retention gave a crystalline product. This was filtered, washed with water and dried at 110 ° C.

The product was a mordenite-like zeolite having the powder X-ray diffraction pattern shown in Table 3.

The product was hexagonal and had a large crystal diameter of 20 to 40 μm, as shown in the scanning electron microscope image shown in FIG.

Table 3 d (A) Relative strength (%) 13.36 35 10.13 10 8.97 100 6.53 35 6.34 12 6.02 6 5.76 17 5.01 2 4.84 2 4.56 7 4.50 25 4.21 2 4.13 5 3.98 35 3.82 11 3.74 5 3.61 2 3.56 3 3.52 4 3.45 38 3.38 25 3.28 3 3.21 30 3.19 25 3.14 3 3.10 3 2.93 4 2.88 10 2.73 1 2.69 3 2.63 1 2.55 3 2.51 5 2.46 3 2.43 2 2.27 1 Example 3 As in Example 1, a reaction mixture having the following composition Was prepared.

SiO ₂ / Al ₂ O ₃ 100 Na ₂ O / SiO ₂ 0.3 H ₂ O / SiO ₂ 30 PEG / SiO ₂ 0.2 The reaction mixture is sealed in an autoclave, heated to 160 ° C. under natural pressure and the temperature is raised for 48 hours. Retention gave a crystalline product. This was filtered, washed with water and dried at 110 ° C.

The product was a mordenite-like zeolite having the powder X-ray diffraction pattern shown in Table 4.

The product was hexagonal and had a large crystal diameter of 30 to 40 μm, as shown in the scanning electron microscope image shown in FIG.

Table 4 d (A) Relative strength (%) 13.49 42 10.19 9 9.03 100 6.55 37 6.36 11 6.04 7 5.78 18 5.56 3 5.02 2 4.85 2 4.51 28 4.22 1 4.13 3 3.98 38 3.82 9 3.75 4 3.62 2 3.56 2 3.52 3 3.46 35 3.38 30 3.28 2 3.22 30 3.20 24 3.15 2 3.10 2 2.93 4 2.89 8 2.70 2 2.63 1 2.55 2 2.51 4 2.46 2 Example 4 In the same manner as in Example 1, a reaction mixture having the following composition was prepared.

SiO ₂ / Al ₂ O ₃ 50 Na ₂ O / SiO ₂ 0.3 H ₂ O / SiO ₂ 30 PEG / SiO ₂ 0.3 The reaction mixture was sealed in an autoclave and heated to 160 ° C. under natural pressure with constant stirring, This temperature was maintained for 48 hours to obtain a crystalline product. After filtration and washing with water,
Dried at 110 ° C.

The product was a mordenite-like zeolite having the powder X-ray diffraction pattern shown in Table 5.

The product was hexagonal and had a large crystal diameter of 20 to 30 μm as shown in the scanning electron microscope image shown in FIG.

Table 5 d (A) Relative strength (%) 13.56 44 10.22 8 9.05 100 6.57 24 6.39 12 6.06 5 5.79 19 5.09 1 4.88 1 4.52 20 4.23 1 4.14 3 3.99 23 3.83 6 3.76 4 3.62 2 3.57 2 3.53 3 3.47 28 3.39 23 3.28 2 3.22 23 3.20 19 3.15 2 3.11 2 2.94 3 2.89 7 2.74 1 2.70 2 2.63 1 2.56 2 2.52 4 2.46 1 Comparative Example The same composition as in Example 4 except that polyethylene glycol was not used. Was prepared.

SiO ₂ / Al ₂ O ₃ 50 Na ₂ O / SiO ₂ 0.3 H ₂ O / SiO ₂ 30 The reaction mixture was sealed in an autoclave and heated to 160 ° C. under natural pressure with constant stirring, and the temperature was raised for 48 hours. Retention gave a crystalline product. After filtration and washing with water,
Dried at 110 ° C.

This product was a mordenite-type zeolite having a powder X-ray diffraction pattern shown in Table 6.

Further, in this product, small crystals of about 5 μ were aggregated as in the scanning electron microscope image shown in FIG.

Table 6 d (A) Relative strength (%) 13.46 47 10.19 18 9.03 84 6.56 58 6.37 24 6.04 13 5.79 20 5.03 4 4.86 3 4.52 40 4.23 2 4.14 4 3.99 84 3.83 16 3.76 14 3.62 5 3.53 9 3.47 100 3.39 63 3.28 8 3.24 28 3.22 47 3.19 56 3.15 6 3.10 5 2.94 7 2.89 23 2.73 2 2.69 5 2.63 2 2.56 6 2.52 13 2.46 5 2.43 3

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1, 2, 3, 4 and 5 are scanning electron microscope images showing the crystal structures of the products of Examples 1, 2, 3, 4 and Comparative Example, respectively.

Claims (4)

(57) [Claims] 1. A zeolite having a hexagonal columnar crystal shape and having a powder X-ray diffraction pattern shown in Table 1. Table 1 X-ray powder diffraction pattern spacing d (A) Relative intensity (%) 13.49 ± 0.88 M 9.03 ± 0.38 VS 6.56 ± 0.21 M 6.37 ± 0.20 W 5.78 ± 0.15 W to M 5.51 ± 0.14 M 3.98 ± 0.07 M 3.46 ± 0.05 M 3.38 ± 0.05 M 3.22 ± 0.05 M 3.20 ± 0.05 M (W, M, and VS in the table represent weak, medium, and very strong, respectively.) 2. The zeolite according to claim 1, comprising crystals having a length of 20 to 50 μm. 3. A molar composition _{SiO 2 / Al 2 O 3 10~200} (Na and / or _{K) 2 O / SiO 2 0.05~1.0} H 2 O / SiO 2 5~50 PEG / SiO 2 0.1~1.0 (PEG The method for producing a zeolite according to claim 1, wherein the reaction mixture comprising polyethylene glycol having an average molecular weight of 400 or less is kept at 100 to 200 ° C for 5 to 100 hours. 4. A method for producing a zeolite according to claim 2, wherein the silica source used for obtaining the reaction mixture is water glass or colloidal silica. .