WO2011052917A2

WO2011052917A2 - Layered double hydroxide variant sepiolite compound, and method for preparing same

Info

Publication number: WO2011052917A2
Application number: PCT/KR2010/007057
Authority: WO
Inventors: 최진호; 박대환; 장명욱; 임병길; 문민호
Original assignee: 주식회사 단석산업; 이화여자대학교 산학협력단
Priority date: 2009-10-26
Filing date: 2010-10-14
Publication date: 2011-05-05
Also published as: CN102712492B; KR101130282B1; WO2011052917A3; KR20110045282A; CN102712492A

Abstract

The present invention relates to a layered double hydroxide variant sepiolite compound and to a method for preparing same. In detail, the present invention relates to a layered double hydroxide variant sepiolite compound and to a method for preparing same wherein a thermal transformation process and a hydration process are performed on layered metal hydroxide which is an anionic compound, so that the layered double hydroxide variant sepiolite compound has a channel structure in which blocks and tunnels intersect each other in a crystallographic axis, and has physicochemical stability, a wide specific surface area, and porosity, and thus improved thermal properties. The sepiolite compound according to the present invention can be applied to a variety of fields including the production of thermal stabilizers, flame retardants, absorbents, filters, spandex, fillers, catalysts, decolorants, etc.

Description

Layered Metal Bilayer Hydroxide Variants Sepiosite Compounds and Methods for Preparing the Same

The present invention relates to a layered metal double layer hydroxide variant Sepiosite compound and a method for preparing the same. More specifically, the layered metal hydroxide, which is an anionic compound, is thermally modified and hydrated, and blocks and tunnels are crystallographic axes. Layered metal hydroxide variant Sepiocite compound with similar crystal structure and physicochemical properties of sepiolite with improved thermal properties due to physicochemical stability, wide specific surface area and porosity It is about a method.

Layered Double Hydoroxide (LDH) is an anionic clay or hydrotalcite-like or bursite-like compound that has a distinct two-dimensional layered structure. Such layered metal bilayer hydroxides can generally be represented by the formula: [M ^{II +} _1-x M ^{III +} _x (OH) ₂ ] [A ^m− ] _{x / m} n · H ₂ O, where M ^{n +} is a metal cation , A ^m- represents an interlayer anion. The metal double layer hydroxide has excellent anion exchange ability, various chemical composition, swelling property, biocompatible and affinity for carbonate anion, biomimetic engineering materials, anion exchanger, stabilizer, absorbent, It is applicable to various fields such as scavenger, catalyst, catalyst support, precursor, and the like.

These layered metal double layer hydroxides are not only naturally occurring but also artificially synthesized anionic compounds, which are dehydrated, dehydrogenated, and deionized according to the synthesis method, external treatment method, or thermal behavior. Phase changes can also lead to changes in the reaction phase. The layered metal double layer hydroxide is inorganic, heat resistant, harmless to the human body, and has an excellent ability to trap chlorine between the double layer structures, thereby improving thermal stability and flame retardancy of polymer resins and the like (Korea Patent No. 10-0548645) No. 10-0527978, 10-0506123, 10-0370961, 10-0909220, etc.). However, due to the chlorine capture action by simple ion exchange, chlorine ions are released again at high temperature, which may generate hydrogen chloride gas. Thus, the development of a material having a stronger thermal chlorine binding ability and excellent thermal stabilizer properties This is necessary.

Meanwhile, the sepiolite formed from montmorillonite, a cationic natural compound, is a natural clay having a microcrystalline structure having a chemical formula of Si ₁₂ Mg ₈ O ₃₀ (OH) ₄ (OH ₂ ) ₄ .8H ₂ O. Unlike ordinary natural clays, sepiolites have a chain-like channel structure, and sepiolites of such chain lattice have very low cation exchange capacity. Sepiolite is known for its various applications due to its needle-like shape, porosity and non-swellability with high specific surface area, excellent adsorption capacity and unique colloidal properties.

The present inventors, through thermal deformation and hydration of a layered metal hydroxide, which is an anionic compound, exhibit a channel structure in which the blocks and tunnels of the sepiolite intersect with the crystallographic axis, and at the same time, have a physicochemical stability and a large specific surface area. And the present invention was completed by preparing a sepiolite-like compound synthesized from a layered metal bilayer hydroxide having improved thermal properties due to its porosity, and the compound was named "sepisite."

Summary of the Invention

SUMMARY OF THE INVENTION An object of the present invention is to provide a sepiocite compound, which is a layered metal hydroxide variant compound, characterized in that the block structure and the tunnel, which are similar to the crystal structure of sepiolite, have a channel type structure in which a tunnel crosses the crystallographic axis. .

Another object of the present invention is to provide a method for producing the sepiocite compound.

In order to achieve the above object, the present invention is represented by the following formula (1), characterized in that the layered metal, characterized in that the crystal structure similar to the crystal structure of the block and the tunnel has a channel-like structure intersecting the crystallographic axis Provided the bilayer hydroxide variant Sepiosite compound:

Formula 1

[M (II) _1-x M (III) _x O _{a / b} (OH) _2-a (A) _{X / n} ] y H ₂ O

Wherein M (II) represents a divalent metal cation; M (III) represents a trivalent metal cation; A is an anionic species covalently bonded to the hydroxide layer, n is the number of charges; x is a number from 0.1 to less than 0.5; a is a number greater than 0 and less than 2; b is a number greater than 0 and less than a; And y is a positive number greater than zero.

The present invention also comprises the steps of (a) heat treating the layered metal bilayer hydroxide at 265 to 275 ° C. to produce a partially dehydrated layered metal double layer hydroxide; And (b) hydrating the partially dehydrated layered metal bilayer hydroxide to produce a sepiosite compound having a channel structure.

Other features and embodiments of the present invention will become more apparent from the following detailed description and the appended claims.

1 is a transmission electron microscope image showing the channel-type crystal structure of sepiolite, A and B are the crystal structure of the natural sepiolite compound, C is a photograph showing the crystal structure of the anhydrous sepiolite .

FIG. 2 is a schematic diagram of Sepiosite prepared by thermal modification and hydration from a layered metal double layer hydroxide (a: layered metal double layer hydroxide, b: dehydrated layered metal double layer hydroxide, c: partial dehydration) Layered metal bilayer hydroxide, d: sepiosite prepared by hydration, e: dehydrated sepiosite, and f: decarbonized layered metal bilayer hydroxide).

FIG. 3 is an X-ray diffractogram of sepiosite (a: layered metal bilayer hydroxide, b: dehydrated layered metal bilayer hydroxide, c: partially dehydrated layered metal bilayer hydroxide, d: hydrated in air Sepiosite prepared, e: Sepiosite prepared by hydration in water at room temperature, f: Sepiosite prepared by hydration in water at 90 ° C, g: Dehydrated Sepiosite)

4 is a transmission electron microscope image of sepiocite (a: layered metal bilayer hydroxide surface structure, b: layered metal bilayer hydroxide internal structure, c: sepiosite surface structure, and d: sepiosite internal structure) .

FIG. 5 shows the results of infrared spectral analysis of Sepiosite (a: layered metal bilayer hydroxide, b: dehydrated layered metal bilayer hydroxide, c: sepiosite, and d: dehydrated sepiosite).

FIG. 6 shows the results of ²⁷ aluminum magic angle spinning nuclear magnetic resonance analysis of Sepiosite (a: layered metal hydroxide, b: dehydrated layered metal hydroxide, c: sepiosite, and d: dehydrated Sepio site).

FIG. 7 shows the results of thermogravimetric analysis of sepiocites (a: layered metal bilayer hydroxide, b: dehydrated layered metal bilayer hydroxide, c: sepiosite, and d: dehydrated sepiosite).

Detailed Description of the Invention and Specific Embodiments

The present invention relates to a layered metal bilayer hydroxide variant sepiocite compound represented by the following Chemical Formula 1 and having a crystal structure similar to the crystal structure of sepiolite:

Formula 1

[M (II) _1-x M (III) _x O _{a / b} (OH) _2-a (A) _{X / n} ] yH ₂ O

Here, the divalent metal cation is Mg ²⁺ , Ca ²⁺ , Co ²⁺ , Cu ²⁺ , Ni ²⁺ , or Zn ²⁺ , and the trivalent metal cation is Al ³⁺ , Cr ³⁺ , Fe ^{3 +} , Ga ³⁺ , In ³⁺ , V ³⁺ , or Ti ³⁺ , wherein the anion may be CO ₃ ^2- , NO ^3- , Cl ⁻ , OH ⁻ , O ^2- , or SO ₄ ^2- . .

In the present invention, the sepiolite may be represented by the following formula (4),

Formula 4

Si ₁₂ Mg ₈ O ₃₀ (OH) ₄ (OH ₂ ) ₄ · 8H ₂ O (Sepiolite)

As shown in A, B and C of FIG. 1 (Eduardo Ruiz-Hitzky, Journal of Materials Chemistry , 2001, 11, 86-91), sepiolite has an elongated form of crystals, A magnesium silicate mineral having a crystal structure, or magnesium silicate hydrate, having a structure in which two tetrahedral silicate layers are connected to oxygen atoms in an octahedral magnesium atom layer formed discontinuously in a central portion.

The sepiolite is present from the montmorillonite existing in nature by heat and pressure chemical modification, montmorillonite is a natural mineral having the following formula (5).

Formula 5

(Al _2-x Mg _x ) (Si ₄ ) O ₁₀ [OH] ₂ M ^{+ n} _{x / n} (montmorillonite)

Here, M is a metal ion between the layers, represents a metal cation that can be easily replaced by a cationic species compared to metal ions such as Si, Al, Mg, etc. in the layer, x is a composition ratio of the interlayer metal ions from 0.2 to 0.7 and n is the valence. In the formula, when x is about 0.2 to 0.7, the interlayer cation is actually easily substituted.

Sepiolite synthesized from such montmorillonite has a very high specific surface area, excellent adsorption capacity, and excellent decolorizng, binding, and thickening ability, and thus, fillers (rubber, pigment, paint, plastic) ), Desiccant, carrier, catalyst, asbestos substitute reinforcement, building material (mortar, tile), refractory, adsorbent, rug, filler, liquid carrier, oil absorbent, clarifier (bleach), boringnier, brake lining It can be used for up and down humidity control.

Sepiocite compounds of the present invention having similar structural characteristics and physicochemical properties to sepiolite may also be applicable to the field where the sepiolite is applicable due to its large specific surface area, porosity, adsorption capacity, and thus excellent thermal properties.

In the present invention, the two-dimensional crystallographic structure of the Sepiocite compound may be characterized in that it has a unique channel-like structure of the chain intersecting the block and the tunnel. As shown in FIG. 4, the conventional layered metal double layer hydroxide or partially dehydrated layered metal double layer hydroxide has a layered structure, as shown in FIG. There is no break. However, in the case of the sepiocite compound according to the present invention, it has a "channel-like structure in which blocks and tunnels cross the crystallographic axis". That is, as shown in (d) of FIG. 4, a break occurs in the hydroxide layer itself, a tunnel is formed on the horizontal axis of the hydroxide layer, and a block (hydroxide layer) tunnel (broken space) intersects on the vertical axis. And, when viewed from the crystallographic axes a, b, and c axes, the structure has a channel or chain structure. Compared with the conventional layered metal double layer hydroxide, the structure of the crystal phase is changed, and thus the accompanying physical and chemical properties are similar to those of the sepiolite.

In the present invention, the sepiocite compound may have a specific surface area of 3 to 4 times larger than that of the layered metal double-cartoxide hydroxide. As shown in the examples below, the sepiocite compounds of the present invention appear to have a specific surface area of about 3.5 times larger than the specific surface area of conventional layered metal bilayer hydroxides.

In the present invention, the sepiocite compound has an improved thermal property of 30 to 40 ° C. than the layered metal double layer hydroxide, and specifically, as shown in FIG. 7, about 30 to 40 more than the layered metal double layer hydroxide. Dehydration reaction occurs at a temperature as high as ℃.

In the present invention, the layered metal double layered hydroxide has a layered crystal structure, exhibits specific interlayer reactivity, and has anion exchange capacity. This is because the hydroxide layer of the layered metal double layer hydroxide has a positive charge and an anion is present between the layers to compensate for this, and the interlayer anion may be replaced with another anion species. It may be characterized by represented by the formula (2):

Formula 2

[M (II) _1-x M (III) _x (OH) ₂ ] ^{X +} [A ^n- ] _{X /} nyH ₂ O

Wherein M (II) represents a divalent metal cation; M (III) represents a trivalent metal cation; A is an anionic species where n is the number of charges of the anion; x is a number from 0.1 to less than 0.5; And y is a positive number greater than zero.

In the present invention, the sepiolite compound is a variant compound derived from the layered metal double layer hydroxide, but has a different structure in terms of lattice structure, but may maintain the particle size and shape of the layered metal hydroxide as it is, or may be modified. .

In the present invention, the divalent metal cation is selected from the group consisting of Mg ²⁺ , Ca ²⁺ , Co ²⁺ , Cu ²⁺ , Ni ²⁺ and Zn ²⁺ , and the trivalent metal cation is Al ³⁺ , Cr ³⁺ , Fe ³⁺ , Ga ³⁺ , In ³⁺ , V ³⁺ , and Ti ³⁺ , wherein the anion is CO ₃ ^2- , NO _3- , Cl-, OH ⁻ , O ^2- , and SO ₄ ^2- may be selected from the group consisting of. The ratio of the divalent metal cation to the trivalent metal cation may be adjusted to 2: 1, 3: 1, 4: 1, etc. to form a layered metal hydroxide having a controlled layer charge. The divalent metal cation, the trivalent metal cation, and the anion are not limited to the above types, and may include all of those known as layered metal bilayer hydroxides in the art.

In the manufacturing process, the layered metal hydroxide may be prepared from various factors such as i) temperature of the reaction solution, ii) concentration of the reaction solution, iii) mixing ratio between the metal cations, iv) temperature of the wash water, and v) drying temperature. It can represent particle size and shape.

In the present invention, the sepiosite compound may be represented by the following Chemical Formula 3:

Formula 3

[Mg _1-x Al _x O _{a / b} (OH) _2-a (CO ₃ ) _{x / 2} ] yH ₂ O

Wherein x is a number from 0.1 to less than 0.5; a is a number greater than 0 and less than 2; b is a number greater than 0 and less than a; And y is a positive number greater than zero.

In another aspect, the present invention provides a method for preparing a partially dehydrated layered metal double layer hydroxide by (a) heat treating the layered metal double layer hydroxide at 265 to 275 ° C; And (b) hydrating the partially dehydroxylated layered metal bilayer hydroxide to produce a sepiocite compound having a channel structure.

In the present invention, the three Pio site of 6 coordination compounds is a hydroxy group with six surrounding the Mg ^2+, Al ³⁺ (octahedral) and 4 hydroxyl groups coordinated to four surrounding the Mg ^2+, Al ³⁺ (tetrahedral structure) Has a mixed structure.

In the present invention, the hydration reaction may be characterized in that the hydrated by supporting the partially dehydrated layered metal bilayer hydroxide in a gaseous or aqueous solvent containing water.

In the present invention, the specific heat treatment temperature range of 265 to 275 ℃ in the step (a) and the channel structure is generated by the hydration reaction in the step (b), the heat treatment time or hydration reaction Time is not so limited.

In the present invention, as shown in Figure 2, the layered metal double layer hydroxide (step a) is heated to 180 ℃ to cause a dehydration reaction (step b), then heat-treated to 270 ℃ partial dehydration reaction (step c ). As the OH group inside the hydroxide layer undergoes partial dehydration reaction, the carbonate anion covalently forms with the hydroxide layer, thereby decomposing the solid two-dimensional layered crystal structure of the layered metal double layer hydroxide. Then, when hydrated, for example, dispersed in water, the hydration reaction takes place (d step), and the crystal structure is rearranged in a channel form to form sepiosite, and when heated to 180 ° C., dehydration of the sepiosite is performed. Inflammation takes place (step e), and a decarbonation reaction (step f) occurs when heat-treated at 580 ° C.

In the reaction process, for example, in the layered metal double layer hydroxide, hydrotalcite is a metahydrotalcite which is partially dehydrated and hydrated at 260 ° C., when hydrated in water or air at room temperature, covalent bonds of carbonate anions The metal in the hydroxide layer maintains a layered structure with a mixture of 6 coordination and 4 coordination, but when hydrated in water above 90 ° C, the covalently bonded carbonate anion and 4 coordination are precursors of layered structure with electrostatic attraction and 6 coordination. (Fig. 5, TS. Stanimirova et al, Journal of Materials Science, 34, 1999, 4153). However, in case of hydration in water of 90 ° C. or higher, the sepiosite compound according to the present invention does not return to the original layered metal double layer hydroxide, and maintains the structure of the sepiosite compound prepared at room temperature.

In the present invention, the layered metal double layer hydroxide comprises the steps of: (a) preparing a precipitated layered salt metal hydroxide crystals by dropwise adding an aqueous base solution to an aqueous solution containing a divalent metal salt and a trivalent metal salt; And (b) hydrothermally synthesizing the layered salt metal hydroxide crystals prepared in step (a) to prepare a layered metal hydroxide.

In the present invention, the divalent metal salt is a magnesium salt, the trivalent metal salt may be characterized in that the aluminum salt.

In the present invention, when the divalent metal salt and trivalent metal salt aqueous solution is titrated with a base solution to synthesize the layered metal double layer hydroxide at room temperature by crystallization and hydrothermal reaction, the divalent metal is magnesium (Mg ²⁺ ), calcium (Ca ²⁺ ) or zinc (Zn ²⁺ ), the trivalent metal may be aluminum (Al ³⁺ ), or iron (Fe ³⁺ ), and the base solution Sodium hydroxide (NaOH) or ammonia (NH ₃ ). The layered metal bilayer hydroxide, in which precipitates are formed and synthesized, can be obtained as particles having various compositions, granularities, and particle sizes, depending on the concentration of metal ions in the synthesis, the ratio of metal ions, proper rate, and total reaction time. have.

In the present invention, the hydrothermal synthesis method is a synthesis method to improve the crystallinity by reacting the crystallized layered metal double-layer hydroxide in a high temperature and high pressure environment, the temperature is 50 ~ 500 ℃, the pressure can be synthesized in the environment of atmospheric pressure or more.

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are only for illustrating the present invention, and it will be apparent to those skilled in the art that the present invention is not to be construed as limited by these examples.

Example 1 Preparation of Layered Metal Bilayer Hydroxide and Sepiosite Compounds

1-1. Manufacture of Layered Metal Double Layer Hydroxide

Mg (NO ₃ ) ₂ · 6H ₂ O (0.4 M) and Al (NO ₃ ) ₃ · 9H ₂ O (0.2 M) were dissolved in distilled water and NaHCO ₃ (0.2 M) was dissolved in aqueous NaOH solution at pH 9∼ It titrated to 10 value and obtained the layered metal double layer hydroxide crystal formed by precipitation. The layered metal double layer hydroxide crystals were stirred at 100 ° C. for 16 hours, washed to remove unreacted salt, and then lyophilized to obtain a layered metal double layer hydroxide.

1-2. Sepiosite Compound Preparation

The layered metal double layer hydroxide obtained in 1-1 was heat-treated at 270 ° C. for 8 hours using a thermogravimetric analyzer (PerkinElmer Pyris Diamond) to obtain a partially dehydrated layered metal double layer hydroxide. The partially dehydrated layered metal bilayer hydroxide was dispersed in distilled water, hydrated by stirring for 7 days, and lyophilized to obtain a sepiosite compound.

Comparative Example 1: Preparation of Dehydrated Layered Metal Hydroxide and Dehydrated Sepiosite

The layered metal bilayer hydroxide and Sepiosite prepared in Example 1 were heated to 180 ° C. at 10 ° C./min using a thermogravimetric analyzer (PerkinElmer Pyris Diamond) to dehydrate and dehydrate the water present therein. Layered metal bilayer hydroxides and dehydrated sepiosites were prepared.

Experimental Example 1: Structure Analysis of Sepiosite

1-1. X-ray diffraction analysis

In order to confirm the crystal structures of the compounds prepared in Example 1 and Comparative Example 1, X-ray diffraction (Rigaku, D / Max 2200) analysis was performed. As a result, as shown in FIG. 3, the interlayer spacing between the layered metal bilayer hydroxide and the dehydrated layered metal bilayer hydroxide was 7.58˜7.60 mm 3, indicating that it is a typical layered structure in which carbonate anions are inserted. The layered metal bilayer hydroxide has become an amorphous structure in which the layered lattice is decomposed. Sepiosite was rearranged to a constant structure with 6.91 Å between layers due to the hydration reaction of the partially dehydrated layered metal bilayer hydroxide. The interlayer spacing of the dehydrated sepiosite was 6.72 Å, so that the distance between layers of the crystallite size was not reduced even after the dehydration reaction. Moreover, even when it hydrated in water of 90 degreeC, it turned out that it does not return to original LDH, but shows the same XRD pattern (FIG.3 (f)) similar to the sepiocite compound manufactured at normal temperature.

1-2. Transmission electron microscope analysis

In order to finely check the shape and crystal structure of the compound prepared in Example 1, transmission electron microscopy (JEOL JEM-2100F) analysis was performed. The internal structure of the compound was observed by fixing each compound to an epoxy resin and cutting it to a thickness of 50 nm. As a result, as shown in Figure 4, the layered metal double-layer hydroxide is hexagonal particles (Fig. 4 (a)), it was confirmed that the layered structure in which the carbonate anion is inserted at about 7.6 kPa between layers (Fig. 4 (b)). In contrast, Sepiosite exhibits a split surface structure of fish-tailed patterns (Fig. 4 (c)), with an interlayer spacing of about 6.9 Å, which is no longer stratified but of block and tunnel intersecting crystallographic axes. It can be seen that the channel structure is formed (FIG. 4 (d)). The structure of Sepiosite is considered to be very similar to that of Sepiolite naturally derived from montmorillonite compounds.

1-3. Infrared spectral analysis

In order to investigate the cause of the channel structure formation of the Sepiosite, infrared spectrum (JASCO FT / IR-6100) analysis was performed. Partially dehydrated Sepiosite, through peak changes at 1360 cm ^-1 , 1025 cm ^-1 , and 3060 cm ^-1 , share carbonate anions intercalated into layers by electrostatic attraction. It can be seen that the combination (Fig. 5).

1-4. ²⁷ Aluminum Magic Angle Spinning Nuclear Magnetic Resonance Analysis

In order to investigate the cause of the channel structure formation of the Sepiocite, ²⁷ aluminum magic angle spinning nuclear magnetic resonance analysis (JASCO FT / IR-6100) analysis was performed. Measured by a 300MHz solid-state NMR spectrometer (Bruker), using a standard sample Al ₂ O ₃ , the transmitter frequency was 104.21 MHz, spinning rate 15 kHz, pulse length 2.3 kHz one pulse.

As a result, as shown in Figure 6, using the ²⁷ aluminum MAS NMR analysis, it can be seen that the surrounding environment surrounding Al ³⁺ in the layer consisting of Mg- (OH) -Al, the layered metal double layer hydroxide is hydroxyl 6 As the dog forms a six-coordinated, octahedral structure surrounding Al ³⁺ , peaks appear at 5.3 ppm ((a) and (b)). On the other hand, in the case of a three site ACF, since due to the partial dehydroxylation hydroxyl six 6 coordination surrounding the Al ^3+, 4 coordinated surrounding the octahedral structure and a hydroxyl group and four Al ^3+, tetrahedral structure are mixed, 5.3 ppm and 68 Peaks in ppm appeared simultaneously ((c) and (d)).

Experimental Example 2: Characterization of Sepiosite

2-1. Specific surface area measurement

The porosity and specific surface area of the layered metal bilayer hydroxide and sepiosite prepared in Example 1 were measured using a nitrogen adsorption-desorption method (ASAP 2000) and a BET equation.

As shown in the results in Table 1, the specific surface area of the mold layer metal hydroxide bilayer is 34.21 m ² / g and a specific surface area of the three sites is Pio channel structure formed through thermal deformation and the hydration reaction to 128.25m ² / g It can be seen that the specific surface area increased by about 3.5 times.

Table 1

2-2. Thermogravimetric test

Thermogravimetric analysis was performed to confirm the thermal properties of the compounds prepared in Example 1 and Comparative Example 1. Using a thermogravimetric analyzer (PerkinElmer Pyris Diamond) was observed to change the mass with the temperature change while raising the temperature to 800 ℃ at 10 ℃ / min.

As a result, as shown in Fig. 7, the layered metal bilayer hydroxide and sepiocite have a pyrolysis curve in three stages of typical dehydration reaction, dehydration reaction, and decarbonate ionization reaction. However, Sepiosite has been confirmed that the temperature range where the dehydration reaction occurs is elevated to about 35 ℃ higher than the layered metal hydroxide to increase the thermal properties. This is due to the stable lattice layer structure in the form of channels, and it was found that it would be useful to increase the thermal properties of sepiocite when added to other media materials.

As described above, the layered metal bilayer hydroxide variant sepiocite compound according to the present invention has a crystal structure similar to that of a channel-type crystal structure in which blocks and tunnels of sepiolite intersect with the crystallographic axis, and have a large specific surface area. Due to the porosity, the thermal properties are improved, and it can be applied to various fields such as heat stabilizers, flame retardants, adsorbents, filters, spandex, fillers, catalysts, and decolorants, which are applications of sepiolite and layered metal double layer hydroxide.

Having described the specific parts of the present invention in detail, it is apparent to those skilled in the art that such specific descriptions are merely preferred embodiments, thereby not limiting the scope of the present invention. something to do. Therefore, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims

A layered metal bilayer hydroxide variant sepiosite compound represented by the following Chemical Formula 1, wherein the block and the tunnel have a channel-like structure that intersects the crystallographic axis:

Formula 1

[M (II) 1-x M (III) x O a / b (OH) 2-a (A) X / n ] yH 2 O

Wherein M (II) represents a divalent metal cation;

M (III) represents a trivalent metal cation;

A is an anionic species covalently bonded to the hydroxide layer, n is the number of charges;

x is a number from 0.1 to less than 0.5;

a is a number greater than 0 and less than 2;

b is a number greater than 0 and less than a; And

y is a positive number greater than zero.
2. Sepiosite compound according to claim 1, which has a specific surface area which is 3 to 4 times larger than the layered metal double-cartoxide hydroxide.
The sepiosite compound according to claim 1, wherein the dehydration reaction occurs at a temperature of 30 to 40 ° C. higher than that of the layered metal double-cartoxide hydroxide.
4. The divalent metal cation of claim 1, wherein the divalent metal cation is selected from the group consisting of Mg 2+ , Ca 2+ , Co 2+ , Cu 2+ , Ni 2+ and Zn 2+ . The trivalent metal cation is selected from the group consisting of Al 3+ , Cr 3+ , Fe 3+ , Ga 3+ , In 3+ , V 3+ , and Ti 3+ , and the anion is CO 3 2- , NO 3-, Cl -, OH -, O 2-, and three sites ACF compound being selected from the group consisting of SO 4 2-.
Sepiosite compound according to claim 1, which is represented by the following formula (3):

Formula 3

[Mg 1-x Al x O a / b (OH) 2-a (CO 3 ) x / 2 ] yH 2 O

Wherein x is a number from 0.1 to less than 0.5;

a is a number greater than 0 and less than 2;

b is a number greater than 0 and less than a; And

y is a positive number greater than zero.
A process for preparing a sepiocite compound according to claim 1 comprising the following steps:

(a) heat treating the layered metal bilayer hydroxide at 265 to 275 ° C. to produce a partially dehydrated layered metal bilayer hydroxide; And

(b) hydrating the partially dehydrated layered metal bilayer hydroxide to produce a sepiosite compound having a channel structure.
According to claim 6, The layered metal double layered hydroxide is seopiosite compound, characterized in that represented by the formula (2):

Formula 2

[M (II) 1-x M (III) x (OH) 2 ] X + [A n- ] X / nyH 2 O

Wherein M (II) represents a divalent metal cation;

M (III) represents a trivalent metal cation;

A is an anionic species where n is the number of charges of the anion;

x is a number from 0.1 to less than 0.5; And

y is a positive number greater than zero.
7. The method according to claim 6, wherein the hydration reaction is carried out by hydrating the layered metal bilayer hydroxide in a gaseous or aqueous solvent containing water.
The method of claim 6, wherein the layered metal bilayer hydroxide is prepared by the following steps:

(a) adding a base aqueous solution to an aqueous solution containing a divalent metal salt and a trivalent metal salt to prepare a precipitated layered salt metal double layer hydroxide crystal; And

(b) preparing a layered metal double layer hydroxide by hydrothermally synthesizing the layered salt metal double layer hydroxide crystals prepared in step (a).
The method of claim 9, wherein the divalent metal salt is a magnesium salt, and the trivalent metal salt is an aluminum salt.