JP2004352541A - Method for producing layered double hydroxide having organic acid between layers - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for easily and efficiently producing a layered double hydroxide having an organic acid between layers at a high purity in such a manner that the generation of a waste liquid is reduced and environmental pollution is not caused. <P>SOLUTION: In the method for producing the layered double hydroxide containing the organic acid between the layers, the water-soluble salt of a monovalent and/or trivalent metal, the water-soluble salt of a divalent metal or the oxide of the divalent metal and the organic acid and/or the metal salt thereof are mixed in alkaline water and thereafter the produced layered double hydroxide is collected. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing a layered double hydroxide containing an organic acid between layers used as a component such as a stabilizer for plastics.
[0002]
[Prior art]
Fatty acids are used as stabilizers and lubricants for plastics, components of cosmetics and pharmaceutical preparations, and the like. Organic sulfonic acids are used in synthetic detergents and the like.
[0003]
When the anion of an organic acid such as a fatty acid or an organic sulfonic acid is intercalated as a guest between layers of the layered double hydroxide as a host, it exhibits excellent properties not found in a single guest or a host. . Such a layered double hydroxide having an organic acid between layers is useful not only as a component such as a stabilizer but also as a catalyst.
[0004]
As a method for producing a layered double hydroxide in which an organic acid anion having a large ionic size is intercalated, Patent Document 1 discloses a limited condition that, besides a metal hydroxide and an organic acid, an anionic component does not coexist. The method by hydrothermal reaction below is described. Non-Patent Document 1 describes a method by ion exchange between an anionic species of a layered double hydroxide and an organic acid. The ion exchange is complicated and the treatment of a large amount of waste liquid after the ion exchange is troublesome.
[0005]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2000-290012 [Non-Patent Document 1] Meyn, K .; Beneke, G .; Lagally, Inorg. Chem. , 29, 5201 (1990).
[0006]
[Problems to be solved by the invention]
The present invention has been made in order to solve the above-mentioned problems, and provides a method capable of easily and efficiently producing a layered double hydroxide having an organic acid between layers without generating waste liquid and causing less environmental pollution. The purpose is to:
[0007]
[Means for Solving the Problems]
The method for producing a layered double hydroxide containing an organic acid between layers according to the present invention, which has been made to achieve the above object, comprises a water-soluble salt of a monovalent and / or trivalent metal, After mixing a water-soluble salt or a divalent metal oxide with an organic acid and / or its metal salt in alkaline water, the resulting layered double hydroxide is fractionated.
[0008]
The monovalent, divalent, and trivalent metal water-soluble salts are preferably various water-soluble inorganic salts other than hydroxide salts, and among them, sulfates, carbonates, nitrates, and hydrochlorides. Still preferred. Regardless of the type of water-soluble salt, the layered double hydroxide has a high purity because the organic acid anion is intercalated between the layers and the inorganic anion is not intercalated. Although the details are not clear, it is presumed that the layered double hydroxide forms a layer having an appropriate interlayer distance such that a relatively large organic acid anion can just fit in, but a very small inorganic anion can pass through. You.
[0009]
Wherein the monovalent metal water-soluble salt is a Li salt, and the divalent metal water-soluble salt is a salt of at least one of Mg, Zn, Ca, Cu, Zr, Co, Ni, Fe, and Mn; The water-soluble salt of a trivalent metal is preferably a salt of at least one of Al, Fe and Co. These salts may be made into an aqueous solution and mixed.
[0010]
The divalent metal oxide is preferably magnesium oxide, more preferably calcined. This oxide may be mixed in a solid state.
[0011]
The organic acid is a monocarboxylic acid represented by R ¹ —COOH (R ¹ — is an alkyl group having 1 to 24 carbon atoms, an alkenyl group having 2 to 24 carbon atoms, or an unsubstituted or alkyl-substituted phenyl group). It is preferable that stearic acid, oleic acid, and palmitic acid be used. Organic _{^{acids, R 2 -SO 3 H (R}} 2 - is R ¹ - same as) may be a monosulfonic acid represented by dodecyl sulfate, dodecyl benzene sulfate and the like and more specifically. The organic ^{acid, HOOC-R 3 -COOH (-R} 3 - is either an alkyl group, an alkenyl group having 2 to 24 carbon atoms, an unsubstituted or alkyl-substituted phenylene group 0-24 carbon atoms) a And more specifically, oxalic acid, maleic acid, and fumaric acid.
[0012]
The method for producing the layered double hydroxide is as follows: 0.1 to 9 molar equivalents of a water-soluble salt of a monovalent and / or trivalent metal; It is preferable that the organic acid and / or its metal salt is mixed in an amount of 0.1 to 9 molar equivalents.
[0013]
This mixing is preferably performed at room temperature to reflux temperature. After mixing, the product may be aged.
[0014]
Preferably, the fractionation is performed by filtration. The filtered layered double hydroxide may be washed with water or an organic solvent and dried.
[0015]
According to this production method, a layered double hydroxide having an organic acid between layers can be produced simply and with good yield.
[0016]
【Example】
Hereinafter, Examples of the method for producing a layered double hydroxide having an organic acid between layers according to the present invention will be described in detail.
[0017]
Examples 1 and 2 are methods for producing a layered double hydroxide having an organic acid between layers to which the present invention is applied. Comparative Example 1 is a method for producing a layered double hydroxide to which the present invention is not applied. Comparative Examples 2 and 3 are fatty acid salts to which the present invention is not applied.
[0018]
(Example 1)
In a four-necked flask equipped with a dropping funnel, a stirrer, a condenser, and a pH meter, 5.21 g of industrial stearic acid (a mixture of 65% stearic acid and 35% palmitic acid) and 29.5 g of ion-exchanged water were added. While heating the mixture to 70 ° C., 2.2 g of a 48% aqueous potassium hydroxide solution was added to adjust the pH value to 10.81 to prepare an aqueous potassium stearate solution. A mixture of 12.1 g of magnesium sulfate heptahydrate and 5.7 g of aluminum sulfate decahydrate was added to 20.1 g of ion-exchanged water, and the mixture was heated to 70 ° C. and dissolved to prepare a mixed metal aqueous solution. While the mixed metal aqueous solution was dropped into the potassium stearate aqueous solution, the reaction mixture was adjusted with a 48% aqueous potassium hydroxide solution as needed so that the pH value of the reaction mixture became 8 to 11, and kept at 75 to 80 ° C. Stir and mix. After completion of the dropwise addition, aging was performed at 75 to 80 ° C. for 6 hours. After aging, the resulting precipitate was filtered, washed with ion-exchanged water, and dried at room temperature, to obtain 13.2 g of a layered double hydroxide having an organic acid intercalated between layers. Mg ²⁺ and Al ³⁺ contained in this layered double hydroxide were quantified by atomic absorption spectrometry. The organic acid contained in the layered double hydroxide was quantified by an acid decomposition method. In the acid decomposition method, 5 g of a sample was weighed and placed in a 200-mL volumetric flask with a marked line, and then two or three boiling stones were added, 50 mL of water was added, and 50 mL of white hydrochloric acid (concentrated hydrochloric acid) was further added. After heating and boiling to confirm the separation of the oil, add about 5% saline solution at a temperature of about 80 ° C so that the oil enters the marked line, and measure the oil content from the numerical difference between the upper and lower lines. Things.
[0019]
As a result, the layered double hydroxide having an organic acid between the layers,
Mg _2.6 was identified as being _{Al 1.0 (OH) 7.2 (Stearate} ) 1.0 · 3.5H 2 O as those represented by the composition formula.
[0020]
(Example 2)
0.066 mol of sodium aluminate was placed in a four-necked flask equipped with a dropping funnel, a stirrer, a condenser, and a pH meter, and dissolved in 300 ml of ion-exchanged water. 0.11 mol of magnesium oxide calcined at 550 ° C. was added to this aqueous solution, followed by stirring at 80 ° C. for 5 minutes. Next, 300 ml of 0.066 mol of an aqueous solution of industrial sodium stearate was added, and the mixture was heated and aged at 80 ° C. for 3 hours. During this time, the pH value of the reaction solution was 12-13. The resulting precipitate was filtered, washed with ion-exchanged water, and dried at room temperature, to obtain 18.2 g of a layered double hydroxide having an organic acid intercalated between layers. Then, Mg ²⁺ and Al ³⁺ contained in the obtained layered double hydroxide obtained by intercalating the organic acid and the fatty acid were quantified by atomic absorption spectrometry. The organic acid contained in the layered double hydroxide was quantified by an acid decomposition method.
[0021]
As a result, the layered double hydroxide having an organic acid between the layers,
Mg _3.1 was identified as being _{Al 1.0 (OH) 8.2 (Stearate} ) that 1.0 · 4.2H ₂ O as represented by the composition formula.
[0022]
(Comparative Example 1)
12.1 g of magnesium sulfate heptahydrate and 5.7 g of aluminum sulfate decahydrate were heated and dissolved in 20.1 g of ion-exchanged water at a temperature of 60 to 70 ° C. to prepare a mixed metal aqueous solution. 29.5 g of ion-exchanged water was added to a four-necked flask equipped with a dropping funnel, a stirrer, a condenser, and a pH meter, and heated to 70 ° C. While the mixed metal aqueous solution was added dropwise thereto, the reaction mixture was adjusted with a 48% aqueous solution of potassium hydroxide as needed so that the pH value of the reaction mixture became 8 to 11, kept at 75 to 80 ° C, stirred and mixed. . After completion of the dropwise addition, aging was performed at 75 to 80 ° C for 6 hours. After aging, the formed precipitate was filtered, washed with ion-exchanged water, and dried at room temperature to obtain a layered double hydroxide having sulfate ions intercalated between layers. Mg ²⁺ and Al ³⁺ contained in this layered double hydroxide were quantified by atomic absorption spectrometry. The sulfate ion was quantified by ion chromatography.
[0023]
As a result, the layered double hydroxide having sulfate ions between the layers is:
Mg _2.6 Al _1.0 (OH) _7.2 (SO ₄ ) _0.5 · 2.9 H ₂ O was identified as the one represented by the composition formula.
[0024]
(Comparative Example 2)
Commercially available magnesium stearate was used as a fatty acid magnesium salt which does not correspond to the layered double hydroxide.
[0025]
(Comparative Example 3)
Commercially available aluminum stearate was used as a fatty acid aluminum salt which does not correspond to a layered double hydroxide.
[0026]
Next, an X-ray diffraction measurement test was performed on the layered double hydroxides of Examples 1 and 2 and Comparative Example 1 and the salts of Comparative Examples 2 and 3 to clarify the three-dimensional structure.
[0027]
(X-ray diffraction measurement test)
For the X-ray diffraction measurement, an X-ray diffractometer was used, copper (Cu Kα λ = 1.54 °) was adopted for the counter electrode, a tube voltage of 40 kV, a tube current of 100 mA, and a scan speed of 2.00 ° / min. And X-rays were irradiated within the measurement angle range 2θ = 2 to 65 ° to obtain a diffraction diagram. In addition, 2θ was determined from the tip of the peak, and the plane distance d was calculated according to Bragg's formula (nλ = 2d sin θ).
[0028]
FIG. 1 shows the diffraction diagrams of the layered double hydroxides of Examples 1 and 2, and FIG. 2 shows the diffraction diagrams of the layered double hydroxide of Comparative Example 1 and the salts of Comparative Examples 2 and 3. In the diffraction diagram, the horizontal axis represents the measurement angle range, and the vertical axis represents the diffraction intensity.
[0029]
The diffraction pattern of the diffraction diagram of the layered double hydroxide of Example 1 shown in FIG. 1 is any of the diffraction patterns of the layered double hydroxide of Comparative Example 1 and the salts of Comparative Examples 2 and 3 shown in FIG. Does not match. The layered double hydroxide of Example 1 is indexed as a hexagonal system having a lattice constant c ₀ = 29.9 ° and a ₀ = 3.04 ° with respect to the result of the X-ray diffraction, (001), (002), ( Since many diffraction peaks of (003), (004), (005), (006), and (007) were observed, it was confirmed that they had a layered structure laminated in the c-axis direction. Further, since the value of the lattice constant a ₀ thereof coincides with the value (3.0 °) generally reported as a layered double hydroxide-like compound, the layered double hydroxide of Example 1 The three-dimensional structure is supported.
[0030]
On the other hand, the value of the lattice constant c ₀ is larger than that of the layered double hydroxide of Comparative Example 1 and another layered double hydroxide in which carbonate ions are intercalated between layers (c ₀ = 7.6 °). Show. Such a result was obtained because a value obtained by subtracting the layer thickness 4.8 ° described in the literature (S. Miyata, Clays Clay Miner., 23, 369 (1975)) from the value of the lattice constant c ₀ was 25 ° ±. 6.0 ° almost coincides with the molecular length value (23 °) of the stearic acid ion described in the literature (Cone Stamp, “Biochemistry”, 4th edition, Tokyo Chemical Dojin (1978), p. 338, 349). ing. From this, a three-dimensional structure as shown in FIG. 3 showing a partial structure of a layered double hydroxide that shows stearic acid ion as an organic acid ion and is just fitted between and intercalated between the layers of the layered double hydroxide. It is considered to have a structure.
[0031]
Next, an X-ray diffraction measurement test was performed on the layered double hydroxide of Example 2 and compared with the diffraction pattern of the diffraction diagram of the layered double hydroxide of Example 1. As shown in FIG. 1 showing the results, the diffraction patterns of the layered double hydroxides of Examples 1 and 2 coincided with each other. Therefore, it was confirmed that the layered double hydroxide of Example 2 also intercalated organic acid ions between layers.
[0032]
【The invention's effect】
As described above in detail, according to the method for producing a layered double hydroxide having an organic acid between layers according to the present invention, the layered double hydroxide can be easily and efficiently produced, and the obtained layered double hydroxide has a high purity. . In addition, the generation of waste liquid is small and does not cause environmental pollution.
[0033]
The layered double hydroxide is useful as a stabilizer / lubricant for plastics, a component for cosmetics / medicinal products, a catalyst, an adsorbent, and a component for a processing agent for plastic working of metal materials.
[Brief description of the drawings]
FIG. 1 is a diffraction diagram of a layered double hydroxide having an organic acid between layers obtained by a production method to which the present invention is applied, which is measured by X-ray crystal diffraction.
FIG. 2 is a diffraction diagram of the layered double hydroxide and the organic acid salt obtained by a production method which does not apply the present invention, which are measured by X-ray crystal diffraction.
FIG. 3 is a schematic view showing a partial structure of a layered double hydroxide having an organic acid between layers obtained by a production method to which the present invention is applied.

Claims (6)

A water-soluble salt of a monovalent and / or trivalent metal, a water-soluble salt of a divalent metal or an oxide of a divalent metal, and an organic acid and / or a metal salt thereof are mixed in alkaline water. Thereafter, a method for producing a layered double hydroxide having an organic acid between layers, wherein the produced layered double hydroxide is fractionated. The layered double water having an organic acid between layers according to claim 1, wherein the water-soluble salts of monovalent, divalent, and trivalent metals are sulfates, carbonates, nitrates, and hydrochlorides. A method for producing an oxide. Wherein the water-soluble salt of the monovalent metal is a Li salt, and the water-soluble salt of the divalent metal is a salt of at least one of Mg, Zn, Ca, Cu, Zr, Co, Ni, Fe, and Mn; 2. The method of claim 1, wherein the water-soluble salt of a trivalent metal is a salt of at least one of Al, Fe, and Co. 3. Method. The method for producing a layered double hydroxide having an organic acid between layers according to claim 1, wherein the oxide of the divalent metal is magnesium oxide. The organic ^{acid, R 1} -COOH (R 1 - or an alkyl group, an alkenyl group having 2 to 24 carbon atoms, an unsubstituted or alkyl group-substituted phenyl group having 1 to 24 carbon ^atoms), R 2 -SO ₃ H (R ² -is the same as R ^1- ), and / or HOOC-R ³ -COOH (-R ³ -is an alkyl group having 0 to 24 carbon atoms, an alkenyl group having 2 to 24 carbon atoms, unsubstituted or alkyl 2. The method for producing a layered double hydroxide having an organic acid between layers according to claim 1, which is any one of a group-substituted phenylene group). 0.1 to 9 molar equivalents of a water-soluble salt of a monovalent and / or trivalent metal; 0.25 to 50 molar equivalents of a water-soluble salt of a divalent metal or an oxide of a divalent metal; 2. The method for producing a layered double hydroxide having an organic acid between layers according to claim 1, wherein the metal salt is 0.1 to 9 molar equivalents.

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