JPS6241168B2 - - Google Patents

Description

Detailed Description of the Invention The present invention provides a method for producing a porous clay material having a pore diameter of 20 angstroms or more, more specifically, a method for producing a porous clay material having a pore diameter of 20 angstroms or more, and more specifically, a method for producing a porous clay material having a pore diameter of 20 angstroms or more, and more specifically, a method for producing a porous clay material having a pore size of 20 angstroms or more, and more specifically, a method for producing a porous clay material having a pore size of 20 angstroms or more. The present invention relates to a method for producing a porous clay material maintained as described above.

Smectite-type minerals include montmorillonite, bentonite, chlorite, beidellite, hectorite, and synthetic mica. For example, in the crystal structure of montmorillonite, a silicate tetrahedral layer, an alumina octahedral layer, and a silicate tetrahedral layer are stacked and bonded to form a single crystal layer. In addition, aluminum, the central metal of the octahedral layer, is partially replaced by magnesium, which has a smaller positive charge.
This gives the layer a negative charge. Alkali metal ions (mainly Ma ⁺ ) corresponding to this negative charge are interposed between the layers to neutralize the charge on the crystal layer. Montmorillonite thus has a large cation exchange capacity and, mainly due to the hydration nature of the exchangeable cations, absorbs a significant amount of water between its layers and exhibits a significantly high swelling property. Other smectite-type minerals also have properties similar to montmorillonite. Attempts have been made to use the above-mentioned smectite minerals as catalyst carriers or adsorbents by utilizing their interlayer structure.

On the other hand, Figure 1 shows the phase diagram when a smectite mineral is mixed with water, where a is the crystal layer and d ₁ is the thickness of the crystal layer (approximately 10 angstroms). Interlayer distance d ₂ in state
varies depending on the mixing ratio of smectite minerals and water, and can take a maximum value of about 500 angstroms if a large amount of water is present. However, when smectite minerals are mixed with water containing cations such as Al ³⁺ and Ca ²⁺ , the positive charge between the layers increases and d ₂
becomes smaller. And if the amount of cations increases
d ₂ ends up being about 10 angstroms.

Furthermore, in conventional production methods, for example, JP-A-54-5884 and JP-A-54-16386, smectite-type minerals are mixed with water and cationic inorganic substances, and the cationic inorganic substances are mixed with interlayer exchangeable cations and ions. Since the production method involves exchange and then hydrolysis, the interlayer distance of the product is about 10 angstroms or less.

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However, when a smectite mineral with a short interlayer distance as described above is used as an adsorbent, a sufficient effect may not be obtained. For example, when refining gasoline using this, low molecular weight hydrocarbons with a small number of carbon atoms in gasoline are inserted between the layers, but relatively large hydrocarbons with a large number of carbon atoms and a relatively large molecular weight are inserted between the layers. It is not inserted, and therefore a sufficient purification effect cannot be achieved.

The present inventors first added a water-soluble polymer compound that dissolves in water and has a neutral charge, a cationic oxide or a cationic hydroxide, and water to a smectite mineral, and mixed them thoroughly. Later, a method was developed to obtain microporous clay with a pore diameter of 20 angstroms or more by drying and firing (Japanese Patent Application Laid-open No. 131878/1983), but as a result of further research, the water-soluble clay described above was developed. Instead of a polymer compound, water-soluble polymer compounds that dissolve in water and have a negative charge, such as polyacrylic acid derivatives, polyvinyl sulfonic acid derivatives, and carboxycellulose derivatives, are used to easily create micropores with a pore diameter of 20 angstroms or more. They discovered that quality clay could be obtained and came up with this invention.

That is, the present invention is a method for producing a microporous clay material, which is characterized in that an anionic water-soluble polymer compound, a cationic inorganic substance, and water are added to a smectite mineral, thoroughly mixed, and then dried and fired. It provides law.

The smectite type mineral in this invention can be selected from, for example, montmorillonite, bentonite, chlorite, beidellite, hectorite, synthetic mica and substituted analogs thereof, or a mixture of two or more thereof.

Further, in the present invention, the inorganic substance interposed between the layers of the smectite mineral to produce a layer spacing of at least 20 angstroms is a cationic oxide or a cationic hydroxide. Specifically, the cationic oxide is, for example, alumina prepared by dissolving monoaluminum phosphate in water, and
Cationic hydroxides have the general formula [Al ₂ (OH) _o
Cl _6-o ] _n , where n is about 3 and m is 10 or less, polyaluminum chloride is dissolved in water and partially hydrolyzed aluminum hydroxide and Al, Cr, Bi, Fe
Add alkali little by little to an aqueous solution of each chloride, nitrate, and sulfate while stirring to dissolve partially hydrolyzed aluminum hydroxide, chromium hydroxide, bismuth hydroxide, iron hydroxide, and ZrOCl in water. This is an aqueous solution of the obtained zirconium hydroxide and trinuclear iron acetate.

In the production of this invention, first, a smectite mineral, water, an anionic water-soluble polymer compound, and a cationic inorganic substance are mixed. The amount of water should be 0.4 ml or more per gram of smectite mineral. Further, the concentration of the aqueous solution of the anionic water-soluble polymer compound is set within a range that exhibits fluidity at a viscosity below that of which the solution slightly flows when tilted. The amount of cationic inorganic material is in the range of 0.05g to 1g per 1g of smectite mineral, and if it is less than 0.05g, it will not form a pillar large enough to expand the interlayer gap, and if it is more than 1g, the porosity will decrease, etc. It is disadvantageous to use it from

The mixing order is such that a cationic inorganic substance is mixed into a mixture of a smectite mineral and an aqueous solution of an anionic water-soluble polymer compound. The state of the smectite mineral and the anionic water-soluble polymer compound aqueous solution after mixing is shown in FIG. Here, the spiral line represents an anionic water-soluble polymer compound. In this state, the appearance of structural viscosity of the anionic water-soluble polymer compound causes the interlayer to expand.

To explain this in more detail, in general, in an aqueous polymer solution, the molecular weight of the polymer increases, and as the concentration increases, the viscosity increases and becomes difficult to flow. This is due to the appearance of structural viscosity due to the formation of a network structure resulting from the so-called "entanglement" phenomenon in which polymer threads become entangled. Then, it begins to exhibit rubber elasticity.

The present invention is characterized in that the characteristics of these anionic water-soluble polymer compounds are applied to the interlayers of smectite minerals to prevent the interlayer distance from becoming small.

Next, a cationic inorganic substance is inserted in the state (), dried at room temperature or up to 150°C, and then heated at 300°C to 700°C to incinerate and remove the anionic water-soluble polymer compound between the layers. As a result, columns of cationic inorganic substances are formed between the layers (). Note that the operation of drying at room temperature or at a temperature up to 150° C. may be omitted.

Therefore, another feature of the present invention is to solidify these cationic inorganic substances between layers of smectite minerals.
The point is that a microporous clay material of a smectite mineral with a long interlayer distance can be obtained by incinerating and removing the anionic water-soluble polymer compound.

Furthermore, as a result of examining the product of this invention by a nitrogen adsorption/desorption method, it was found to be a microporous material having a pore diameter of 20 angstroms or more, as shown in FIG. Further, the maximum surface area of pores with a diameter of 20 angstroms or more is about 160 m ² /g, and the maximum total surface area is about 230 m ² /g. The nitrogen capacity is a maximum of about 0.2 ml/g, the specific volume is a maximum of about 0.6 cm ³ /g, and the porosity is a maximum of about 0.3.

These microporous clay materials are useful as catalyst supports and adsorbents and, when oriented, are also useful in high performance thermal insulation materials.

Examples of this invention will be shown below.

Example 1 After dissolving 0.4 g of sodium polyacrylate with a degree of polymerization of 200 in 5 ml of water, 1.00 g of sodium montmorillonite is added, followed by stirring and mixing. into the mixture
Add 2 ml of 10 weight percent polyaluminum chloride aqueous solution, stir and mix, and then heat to 50°C.
After drying, it was baked in an electric furnace at 500°C for 15 hours in an air atmosphere. As a result of investigating the pore size, surface area, nitrogen capacity, specific volume, and porosity of the product using the nitrogen adsorption/desorption method, the pore size with the maximum pore distribution was 31 angstroms, and the surface area was 157 m for pore sizes of 20 angstroms or more. The total surface area was 228 ^{m 2} /g, the nitrogen capacity was 0.17 ml/g, the specific volume was 0.57 cm ³ /g, and the porosity was 0.30.

Example 2 0.4g of sodium polyacrylate with a degree of polymerization of 2000
After dissolving in 5 ml of water, add 1.00 g of sodium montmorillonite and stir to mix. Add 2 ml of a 10 weight percent polyaluminum chloride aqueous solution to the mixture, stir and mix, and then
The sample was left in a dryer at 500°C for 15 hours after drying, and then baked in an electric furnace in an air atmosphere at 500°C for 15 hours. As a result of examining the pore size, surface area, nitrogen capacity, specific volume, and porosity of the product using the nitrogen adsorption/desorption method, the pore size with the maximum pore distribution was 31 angstroms, and the surface area was 157 m for pore sizes of 20 angstroms or more. The total surface area was 229 ^{m 2} /g, the nitrogen capacity was 0.19 ml/g, the specific volume was 0.59 cm ³ /g, and the porosity was 0.32.

Example 3 0.4g of sodium polyacrylate with a degree of polymerization of 5000
After dissolving in 5 ml of water, add 1.00 g of sodium montmorillonite and stir to mix. Add 2 ml of a 10 weight percent polyaluminum chloride aqueous solution to the mixture, stir and mix, and then
The sample was left in a dryer at 500°C for 15 hours after drying, and then baked in an electric furnace in an air atmosphere at 500°C for 15 hours. As a result of investigating the pore size, surface area, nitrogen capacity, specific volume, and porosity of the product using the nitrogen adsorption/desorption method, the pore size with the maximum pore distribution was 31 angstroms, and the surface area was 113 m for pore diameters of 20 angstroms or more. The total surface area was 176 ^{m 2} /g, the nitrogen capacity was 0.13 ml/g, the specific volume was 0.53 cm ³ /g, and the porosity was 0.25.

Example 4 After dissolving 0.4 g of sodium polyacrylate with a degree of polymerization of 200 in 5 ml of water, 1.00 g of sodium montmorillonite was added, followed by stirring and mixing. into the mixture
Add 5 ml of a 10 weight percent polyaluminum chloride aqueous solution, stir and mix, and then heat to 50°C.
After being left in a dryer for one day, it was baked in an electric furnace in an air atmosphere at 500°C for 15 hours. As a result of investigating the pore size, surface area, nitrogen capacity, specific volume, and porosity of the product using the nitrogen adsorption/desorption method, the pore size with the maximum pore distribution was 31 angstroms, and the surface area was 45 m for pore diameters of 20 angstroms or more. ² /g, total surface area is 81m ² /g, nitrogen capacity is 0.14ml/g, specific volume is
The porosity was 0.54 cm ³ /g and 0.26.

Example 5 0.4g of sodium polyacrylate with a degree of polymerization of 5000
After dissolving in 5 ml of water, add 1.00 g of sodium montmorillonite and stir to mix. Add 5 ml of a 10 weight percent polyaluminum chloride aqueous solution to the mixture, stir and mix, and then
The sample was left in a dryer at 500°C for 15 hours after drying, and then baked in an electric furnace in an air atmosphere at 500°C for 15 hours. As a result of investigating the pore size, surface area, nitrogen capacity, specific volume, and porosity of the product by nitrogen adsorption/desorption method, the pore size with the maximum pore distribution was 31 angstroms, and the surface area was 38 m for pore diameters of 20 angstroms or more. ² /g, total surface area is 87m ² /g, nitrogen capacity is 0.11ml/g, specific volume is
The area was 0.51 m ³ /g, and the porosity was 0.22.

Example 6 After dissolving 0.4 g of sodium polyacrylate with a degree of polymerization of 200 in 5 ml of water, 1.00 g of synthetic mica was added.
and stir to mix. 2 ml of 10% by weight polyaluminum chloride was added to the mixture, which was further stirred and mixed, and then left in a dryer at 50°C for one day. After drying, it was fired at 500°C in an electric furnace in an air atmosphere for 15 hours. Product pore size, surface area, nitrogen capacity,
As a result of investigating the specific volume and porosity using nitrogen adsorption/desorption method, the pore diameter showing the maximum pore distribution was 30 angstroms.
The surface area is 55 m ² /g for pore sizes of 20 angstroms or more, the total surface area is 79 m ² /g, the nitrogen capacity is 0.24 ml/g, the specific volume is 0.64 cm ³ /g, and the porosity is 0.38.
It was hot.

Example 7 0.4g of sodium polyacrylate with a degree of polymerization of 5000
After dissolving in 5 ml of water, add 1.00 g of synthetic mica and stir to mix. 2 ml of 10% by weight polyaluminum chloride was added to the mixture, which was further stirred and mixed, and then left in a dryer at 50°C for one day. After drying, it was fired at 500°C in an electric furnace in an air atmosphere for 15 hours. Product pore size, surface area, nitrogen capacity,
As a result of investigating the specific volume and porosity using nitrogen adsorption/desorption method, the pore diameter showing the maximum pore distribution was 30 angstroms.
The surface area is 62 m ² /g for pore diameters of 20 angstroms or more, the total surface area is 82 m ² /g, the nitrogen capacity is 0.18 ml/g, the specific volume is 0.58 cm ² /g, and the porosity is 0.31.
It was hot.

[Brief explanation of the drawing]

Figure 1 shows a state in which a smectite mineral is swollen and contains water between its layers. FIG. 2 shows the pore generation process in a manufacturing method in which an anionic water-soluble polymer compound and a cationic inorganic substance are inserted between the layers of a smectite mineral. FIG. 3 is a pore distribution curve of the microporous clay material of the present invention obtained by the nitrogen desorption method. 〓〓〓〓

Claims (1)

[Claims] 1. A method for producing a microporous clay material, which comprises adding an anionic water-soluble polymer compound, a cationic inorganic substance, and water to a smectite mineral, thoroughly mixing the mixture, and then drying and firing the mixture.