JPS6250406B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to novel microporous clay materials useful as catalyst supports and adsorbents. More specifically, this invention relates to a novel microporous clay material in which an anionic water-soluble polymer compound and an inorganic substance are interposed between the layers of montmorillonite group minerals, and the interlayer spacing is maintained at 20 angstroms or more. be. Montmorillonite group minerals, also called smectites, are a group of minerals that make up clay, and all of them belong to phyllosilicate minerals that have a three-layered structure. A typical example of this is montmorillonite, which consists of a silicate tetrahedral layer.
Alumina octahedral layers and silicate tetrahedral layers 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 lower positive charge, which gives the layer a negative charge.
Alkali ions (mainly
Na ⁺ ) is interposed between the layers and neutralizes the charge in the crystalline layers.

Therefore, montmorillonite has a large cation exchange capacity. Also, due to the hydration properties of the exchangeable cations, a significant amount of water is absorbed between the layers, resulting in extremely high swelling properties. Other montmorillonite group minerals have properties similar to montmorillonite, and all of these minerals are used as catalyst carriers, adsorbents, etc. by taking advantage of their layered structures.

Conventional porous clay materials, such as JP-A-54-5884
No. 54-16386, cationic hydroxy metal complexes, aluminum chlorohydroxide complexes, silicates,
It is a material containing phosphate, zirconia, etc.
The interlayer spacing is about 10 angstroms or less.

However, when using montmorillonite group minerals with short interlayer distances as described above as a heat insulating material, sufficient effects may not be obtained. For example, if this material is used to create an insulating material by applying orientation, water will clog between the layers even at a relative humidity of about 10%. Therefore, a sufficient heat insulation effect cannot be achieved.

In view of the above circumstances, this invention was developed as a result of intensive research aimed at producing a microporous clay material made of montmorillonite group minerals with a relatively long interlayer distance. The material was discovered. A cross-sectional view of the structure of the microporous clay material of this invention is shown in FIG. a is a crystalline layer of montmorillonite group minerals, and its thickness d ₁ is approximately 10 angstroms.
Spirals and b are anionic water-soluble polymer compounds and inorganic substances inserted between the layers, and serve as pillars that support the interlayers. And an interlayer spacing of d ₂ appears.
The microporous clay material of this invention has a d ₂ of 20 angstroms or more.

The montmorillonite group minerals in this invention include, for example, montmorillonite, bentonite, chlorite,
It can be selected from one or more mixtures of beidellite, hectorite, synthetic mica, and substituted analogs thereof.

In addition, anionic water-soluble polymer compounds include polyacrylic acid derivatives, polyvinylsulfonic acid derivatives,
selected from the group consisting of carboxycellulose derivatives and mixtures thereof. Inorganic substances are gelled products of silica sol reacted with cations, and these cations include calcium, barium, magnesium, aluminum, iron, nickel, cobalt,
Ions of divalent or higher valence such as ruthenium and lanthanide are used.

As a result of examining the interlayer spacing of the microporous clay material of the present invention by a nitrogen adsorption/desorption method, as shown in FIG. 2, the interlayer spacing is mainly 20 angstroms or more and 60 angstroms or less. In addition, the surface area with an interlayer spacing of 20 angstroms or more is approximately 300 m ² /
g, total surface area is about 500 m ² /g, nitrogen capacity is about 0.4 ml / g, specific volume is about 0.8 cm ² /g, porosity is about 0.5
It is.

Figure 3 shows the state when montmorillonite group minerals are mixed with water, where a is the crystal layer and d ₁ is the thickness of the crystal layer (approximately 10 angstroms). The interlayer distance _d3 changes depending on the mixing ratio of Montmorillonite group minerals and water.
If a large amount of water is present, the value can be up to about 500 angstroms. However, when montmorillonite group minerals are mixed with water containing cations such as Ca ²⁺ and Al ³⁺ , the positive charge between the layers increases and d ₃ becomes smaller. And if the amount of cations increases, d ₃ will eventually become about 10 angstroms.

Furthermore, in conventional production methods, for example, JP-A-54-5884 and JP-A-54-16386, montmorillonite group minerals are mixed with water and cationic inorganic substances, and the cationic inorganic substances are exchanged with interlayer exchangeable cations. Since the production method involves ion exchange followed by hydrolysis, the interlayer distance of the product is approximately 10 angstroms or less.

However, as explained above in the "microporous clay material", when montmorillonite group minerals with short interlayer distances are used as a heat insulating material, sufficient effects may not be obtained.

The microporous clay material of this invention is produced by adding silica sol, an anionic water-soluble polymer compound, a cationic co-supplant material, and water to montmorillonite group minerals, thoroughly mixing the mixture, and then drying the mixture. can do.

The montmorillonite group minerals in this invention include, for example, montmorillonite, chlorite, beidellite,
It can be selected from one or a mixture of two or more of hectorite, synthetic mica and substituted analogs thereof.

The anionic water-soluble polymer compound used in the production can be selected from polyacrylic acid derivatives, polyvinylsulfonic acid derivatives, carboxycellulose derivatives, and mixtures of one or more of these.

Further, as the silica sol, one containing polymeric silica, silicate ions, etc., and which reacts with cations to form a gel is used. This cation is
Ions of divalent or higher valent metals such as calcium, barium, magnesium, aluminum, iron, nickel, cobalt, ruthenium, and lanthanide are used.

In the production of this invention, first, the montmorillonite group mineral, water, an anionic water-soluble polymer compound, and an inorganic substance are mixed.

The amount of water is 0.4ml per gram of montmorillonite group minerals.
The above shall apply. 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 that is below the level where the solution slightly flows when tilted. The inorganic content ranges from 0.05g to 1g per 1g of montmorillonite group minerals, and is used because 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. It is disadvantageous to do so. The order of mixing is to mix a mixed aqueous solution of an anionic water-soluble polymer compound and an inorganic substance with a montmorillonite group mineral, or to mix an inorganic substance with a mixture of a montmorillonite group mineral and an aqueous solution of an anionic water-soluble polymer compound. Either is fine. After mixing as above, cations are added. The cation content is 1×10 ^-4 mol to 1× per gram of montmorillonite group minerals.
It is in the range of 10 ^-2 mol, and if it is less than 1 x 10 ^-4 mol, the inorganic substance will not gel sufficiently, and if it is more than 1 x 10 ^-2 mol, it is disadvantageous to use it because the porosity will decrease. . Furthermore, aluminate ions may be added in addition to cations. The addition amount should be equivalent to the inorganic substance.

The state after mixing is shown in FIG. Here, C is a gel produced by a reaction between an inorganic substance and a cation or an aluminate ion. Gel generation will be explained in detail. The inorganic substance in this invention is polymeric silica (silica sol), which is a colloidal form of negatively charged amorphous silica particles dispersed in water, and the particles have a spherical shape. -SiOH groups and -OH ^- ions are present on the surface of the particles, and an electric double layer is formed by the alkali ions added as a stabilizer, which is stabilized by the reaction between the particles. If this charge balance is disrupted by the addition of cations, etc., viscosity increase, gelation, aggregation, etc. occur. The degree of gelation varies depending on the type, concentration, temperature, etc. of the cations added. When a gel is dried, it changes from a water-containing gel to a dry gel. combination) A strong dry gel solid is obtained. The thermal changes of this dried gel were measured by differential thermal analysis and thermogravimetric analysis, and the results are as follows. At about 150°C, the water adsorbed on the silica gel dehydrates, resulting in a weight loss of about 5%. 400℃
Silanol dehydration occurs at ~700°C. No particle change is observed up to this temperature.

The spiral line in FIG. 4 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, as the molecular weight of the polymer increases and 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 montmorillonite group minerals so that the interlayer distance does not become smaller due to the insertion of inorganic substances and cations.

Next, water between the layers is removed by drying at room temperature or up to 200°C under the conditions shown in Figure 4.
The spreading of the anionic water-soluble polymer compound becomes smaller, and pillars of inorganic matter are formed between the layers (first
figure).

Therefore, another feature of the present invention is that these anionic water-soluble polymer compounds and inorganic substances are fixed between the layers of the montmorillonite group mineral, and then dried to form fine pores of the montmorillonite group mineral with a long interlayer distance. The advantage is that high-quality clay materials can be obtained.

The product of the present invention was examined by a nitrogen adsorption/desorption method, and as shown in FIG. 2, it was found to be a microporous clay material mainly having an interlayer spacing of 20 angstroms or more. Further, the surface area with an interlayer spacing of 20 angstroms or more is about 300 m ² /g at maximum, and the total surface area is about 500 m ² /g at maximum. Nitrogen capacity is up to approx.
The specific volume is 0.4 ml/g, the maximum specific volume is approximately 0.8 cm/g, and the maximum porosity is approximately 0.5.

These microporous clay materials, when oriented, are useful in high performance insulation materials.

Examples of this invention will be shown below.

Example 1 0.018 g of sodium polyacrylate having a degree of polymerization of 22,000 to 70,000 is dissolved in 10 ml of water.

0.45 ml of 31 weight percent silica sol aqueous solution (manufactured by Catalysts Kasei Kogyo, SI-350) in 10 ml of dissolved 0.18 weight percent sodium polyacrylate aqueous solution
Add and stir to mix. Add 1.00 g of sodium montmorillonite to the mixed aqueous solution and stir and mix. To the mixture thus obtained, 3 ml of a 3.2 weight percent AlCl ₃ .6H ₂ O aqueous solution was added, stirred and mixed, and then left to dry in a dryer at 50° C. for 2 days. As a result of investigating the pore diameter, surface area, nitrogen capacity, specific volume, and porosity of the product by nitrogen adsorption/desorption method,
The pore diameters at which the pore distribution peaks are 38 and 30 angstroms, the surface area is 206 m ² /g for pore diameters of 20 angstroms or more, and the total surface area is 297 angstroms.
m ² /g, nitrogen capacity is 0.25ml/g, specific volume is 0.65cm ³ /
g, and the porosity was 0.38.

Example 2 0.036 g of sodium polyacrylate having a degree of polymerization of 22,000 to 70,000 is dissolved in 10 ml of water. Dissolved 0.36 weight percent sodium polyacrylate in water 10
ml, add 0.90ml of 31% by weight silica sol aqueous solution (manufactured by Catalysts Kasei Kogyo, SI-350), stir,
Mix. Add 1.00 g of sodium montmorillonite to the mixed aqueous solution and stir and mix.
The resulting mixture contains 3.2% by weight.
After adding 3 ml of AlCl ₃ .6H ₂ O aqueous solution and stirring and mixing, the mixture was left to dry for 2 days in a drying oven at 50°C.
The pore size, surface area, nitrogen capacity, specific volume, and porosity of the product were investigated using the nitrogen adsorption method.The pore size at which the pore distribution peaks was 41 and 30 angstroms, and the surface area was
242m ² / for pore diameters of 20 angstroms or more
g, total surface area is 349 m ² /g, nitrogen capacity is 0.31
ml/g, specific volume was 0.71 cm/g, and porosity was 0.44.

Example 3 0.064 g of sodium polyacrylate having a degree of polymerization of 22,000 to 70,000 is dissolved in 20 ml of water. Dissolved 0.032 weight percent sodium polyacrylate in water 20
1.8 ml of a 31 weight percent silica sol aqueous solution (SI-350, Catalysts & Chemicals Industries, Ltd.) is added to each ml, and the mixture is stirred and mixed. Add 1.00 g of sodium montmorillonite to the mixed aqueous solution and stir and mix. The resulting mixture contained 3.2% by weight _AlCl3 .
After adding 3 ml of 6H ₂ O aqueous solution and stirring and mixing,
It was left to dry in a dryer at 50°C for 2 days. 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 at which the pore distribution peaks is 48 angstroms, and the surface area is 287 m for pore diameters of 20 angstroms or more. ² /
g, total surface area is 475 m ² /g, nitrogen capacity is 0.38
ml/g, specific volume was 0.78 cm ³ /g, and porosity was 0.49.

[Brief explanation of the drawing]

FIG. 1 shows a cross-sectional view of the structure of the microporous clay material of the present invention. FIG. 2 is a pore distribution curve of the microporous clay material of the present invention obtained by the nitrogen adsorption/desorption method. Figure 3 shows the swollen state of montmorillonite group minerals containing water between their layers. FIG. 4 shows the state before drying in a production method in which an anionic water-soluble polymer compound and an inorganic substance are inserted between layers of montmorillonite group minerals.

Claims (1)

[Claims] 1. A microporous clay material containing an anionic water-soluble polymer compound and silica between layers of montmorillonite group minerals, and having an interlayer spacing of 20 angstroms or more.