JPH0210763B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical field to which the invention pertains] The present invention relates to a method for producing a germanate of a divalent metal. In particular, the present invention relates to a method for producing germanate, which is suitable for modifying materials such as dielectrics. [Description of the Prior Art] Conventionally, germanates such as barium germate (BaGeO ₃ ) have a low melting point, so if they are added to ceramic dielectric materials such as barium titanate (BaTiO ₃ ), It is believed that dielectrics can be sintered at lower temperatures. There are two conventional methods for this addition: The first method is barium carbonate (BaCO ₃ )
barium salts and germanium oxide (GeO ₂ ) such as
This is a method in which a required amount of is added, followed by calcination, pulverization, and calcination to cause a reaction. The second method is the above-mentioned barium salt and GeO ₂
In this method, a germanate such as BaGeO ₃ is synthesized in advance by mixing and firing, and after pulverizing this, it is added to a ceramic material and fired. According to these conventional methods, especially in the first method, BaO and GeO ₂ do not necessarily distribute or react uniformly in ceramics, and it is difficult to stabilize their properties. In addition, both the first and second methods have the disadvantage that impurities are likely to be mixed in from the grinding device during grinding, resulting in deterioration of the properties. In recent years, electronic components have been required to be smaller and have more advanced characteristics, and the raw material powder used for them has therefore become more required than ever to have uniform composition and high-purity fine particles. It's coming. In manufacturing processes, there is also an increasing interest in producing materials using as little energy as possible. [Object of the Invention] The present invention solves the above-mentioned drawbacks, and provides germanate with (a) a uniform and desired composition, (b) high purity and fine particles, and (c) low cost and low energy consumption. It is an object of the present invention to provide a method for producing germanate that can be produced. [Summary of the Invention] The first feature of the present invention includes a step of mixing and reacting a divalent metal alkoxide and germanium alkoxide, and a step of hydrolyzing this reaction product to obtain a germanate salt. In the method for producing germanate. Note that it is preferable that the alkoxide of the divalent metal and the germanium alkoxide are reacted in a state in which they are dissolved in an organic solvent. Further, the reaction temperature between the divalent metal alkoxide and the germanium alkoxide is 0°C to 100°C.
It is preferable that Further, the reaction temperature for hydrolyzing to obtain germanate is preferably 0°C to 100°C. Further, it is preferable to obtain a germanate by hydrolysis with an alkaline aqueous solution. In addition, the above divalent metals include Ba, Sr, Ca, Mg, Pb,
1 selected from Zn, Co, Mn, Cd, Ni and Cu
Or two or more metals are preferable. The second feature of the present invention is the step of mixing and reacting a divalent metal alkoxide and germanium alkoxide, and hydrolyzing this reaction product to produce a hydrous germanate and/or an amorphous germanate. and heating the hydrous germanate and/or amorphous germanate to obtain an anhydrous and/or crystalline germanate. The heating temperature of the above amorphous germanate is 400℃.
The temperature is preferably at least .degree. C. and below the decomposition starting temperature of germanate. As used herein, alkoxide refers to a compound in which the hydrogen atom of the OH group of an alcohol is replaced with a metal atom. [Supplementary Explanation] The present invention will be further explained below. The present invention is to produce a germanate of a divalent metal using an alkoxide as a starting material. In the present invention, it is first necessary to produce an alkoxide of a divalent metal and germanium. This divalent metal is
Ba, Sr, Ca, Mg, Pb, Zn, Co, Mn, Cd, Ni
It is preferably one or more metals selected from Cu and Cu. In particular, divalent metals such as Ba, Sr, Ca, and Mg have high reactivity with alcohol, so they can be directly reacted with alcohol to produce alkoxides as shown in the following general formula. M+2ROH→M(OR) ₂ +H ₂ ... (However, M is a divalent metal. The same applies hereinafter.) Heating may be performed to advance this alkoxide production reaction. In particular, since Mg reacts slowly with alcohol, a catalyst such as I ₂ or HgCl ₂ may be added, but care must be taken as this may cause contamination of impurity ions and liberation of mercury. This reaction between metal and alcohol proceeds from the surface of the metal to the inside, but the reaction may be slowed down because the alkoxide produced covers the metal surface. In order to prevent this, it is preferable to add benzene or other solvent. Divalent metals Pb, Zn, and Ge are created by other methods because it is difficult to directly react these metals with alcohol. In the case of Pb, lead acetate (Pb
(CH ₃ COO) ₂ ) and sodium alkoxide (NaOR) using an exchange reaction to synthesize lead alkoxide. Pb(CH ₃ COO) ₂ +2NaOR→ Pb(OR) ₂ +2CH ₃ COONa... In the case of Zn, zinc chloride (ZnCl ₂ ) and sodium alkoxide (NaOR) are combined as shown in the following formula.
Synthesize from. ZnCl ₂ +2NaOR→Zn(OR) ₂ +2NaCl... Also, in the case of Ge, germanium halide,
In particular, germanium tetrachloride (GeCl ₄ ) is preferably used. To synthesize germanium alkoxide from GeCl ₄ , it is best to use anhydrous ammonia, as shown in the following general formula. GeCl ₄ +4ROH+4NH ₃ → Ge(OR) ₄ +4NH ₄ Cl... When producing this alkoxide, methanol, ethanol, propanol, butanol, etc. are preferable as the alcohol. The type of alcohol used is largely related to the reactivity in producing the alkoxide, but when the produced alkoxide is used as a starting material for the present invention, the type of alkyl group in the alkoxide is not essentially important. The metals, alcohols, and metal salts that are the starting materials for this alkoxide have the characteristic that they can be purified by relatively easy physical or chemical methods, and they do not contain any unnecessary ions. The alkoxide synthesized as a starting material can be easily reduced to 0.1% or less of impurities without any particular purification. In order to further increase the purity of the alkoxide, solid alkoxides are recrystallized, and liquid alkoxides are subjected to distillation, etc. Divalent metal alkoxide M obtained as above
(OR) ₂ and germanium alkoxide Ge(OR) ₄ or their organic solvent solutions are mixed to the desired composition and then hydrolyzed by gradually adding decarboxylated distilled water, dilute aqueous ammonia, or other alkaline aqueous solution. When this is done, a white powder precipitate is formed. If this is separated by filtration, germanate salts are obtained. Here, there is no difference in the properties of the product whether distilled water or alkaline aqueous solution is used for hydrolysis, but the hydrolysis of germanium alkoxide is faster when hydrolyzed in alkaline conditions. Germanate formation is also faster. In order to make this alkaline state, in addition to hydrolyzing with an alkaline aqueous solution, an alkali alkoxide, an amine, etc. may be added to the alkoxide solution to make it alkaline in advance. The reaction between the divalent metal alkoxide and germanium alkoxide is preferably carried out in a solvent. Suitable organic solvents include benzene, alcohol, hexane, and the like. When the reaction temperature is higher than the boiling point of the solvent, the reaction can be carried out under pressure in a pressure vessel. It is preferred that the reaction temperature of both alkoxides does not exceed 100°C for most alkoxides.
Although it is not necessary to carry out the reaction by cooling, a desirable reaction temperature is 0°C to 100°C. A particularly desirable reaction temperature is 40°C to 100°C. In addition, the reaction temperature for hydrolysis is 0°C to 100°C.
℃ is preferable. Further, hydrolysis is not limited to water alone, but can also be performed with aqueous ammonia or other alkaline aqueous solutions. According to the method of the present invention, the germanate obtained by the reaction may be obtained as a hydrate or an anhydride depending on the reaction conditions, the blending ratio of the raw materials used, the type of divalent metal used, etc. When obtained, it may be obtained in an amorphous form, or it may be obtained in a crystalline form, or these forms may coexist, but regardless of which form it is obtained, it can be added as a modifying material for dielectrics, etc. In this case, there is no change in the properties of the dielectric, etc. When obtained as a hydrate, it can be easily converted into an anhydride by heating or drying as necessary. Moreover, even when obtained in an amorphous state, a crystalline germanate can be easily obtained by heating. This heating temperature is preferably 400° C. or higher and lower than the decomposition starting temperature of the germanate, but it can also be obtained at a lower temperature or by vacuum heating. The temperature for this crystallization varies depending on the type of divalent metal, reaction conditions, etc. For example, if the divalent metal is Ba, the temperature is 800℃.
However, crystalline germanate can be obtained at heating temperatures of 400°C for Sr and 800°C for Mg. The heating atmosphere in this case is air, neutral, oxidizing, or reducing atmosphere. The germanate in the final form is preferably an anhydrous germanate when used, but it does not necessarily have to be in an anhydrous state when the ceramic material is added, and it can be heated together with the ceramic material after the addition. It can also be used as an anhydrous germanate. In either case, when a germanate is obtained directly by the above reaction, or an anhydrous and/or crystalline germanate is obtained by heating, the germanate obtained is 0.01~ They are fine particles with a particle size of 0.1 μm. Furthermore, since the heat treatment temperature for crystallizing the germanate is lower than the conventional firing temperature of 1000°C or higher, it is easy to loosen agglomerates.
Furthermore, the germanate obtained by chemical analysis is a highly pure substance with impurities of 0.1% or less, and the ratio of germanium atoms to divalent metal atoms (M/Ge)
When mixed at M/Ge=1, the product is M/Ge
It is confirmed that =0.98 to 1.02. [Effects of the Invention] As described above, according to the present invention, a germanate with high purity and fine particles can be obtained by reacting a divalent metal alkoxide with a germanium alkoxide and hydrolyzing it to obtain a germanate. The atomic ratio is extremely close to the target, and it has the excellent effect of being able to be produced uniformly and at low cost with less energy through a low temperature reaction process of 1000°C or less. [Explanation based on Examples] Next, the present invention will be explained in more detail using Examples, but the gist of the present invention is not limited to the following Examples. Example 1 High purity Ba metal 20.0g, high purity Sr metal 12.8g,
Take 3.5 g of high-purity Mg metal, put these metals together with 45 g of dehydrated isopropanol in 200 ml of benzene, and react under reflux at 80°C. A benzene solution of the metal isopropoxide is obtained in about 2 to 24 hours in each case with H ₂ evolution. In addition, by dissolving 31.2 g of anhydrous GeCl _4, a special grade reagent, in 200 ml of benzene with 70 g of isopropanol, and passing dry ammonia gas through this solution, NH ₄ Cl begins to be generated, and ammonia gas is removed from the reaction vessel in about 1 hour. It can be seen that germanium alkoxide production has been completed. The generated NH ₄ Cl is separated by filtration to obtain a benzene solution of germanium alkoxide. The divalent metal alkoxide and germanium alkoxide obtained in this way each have an atomic ratio of 1.
Mix and reflux at 80°C for over 1 hour. Next, while refluxing, 15 ml of 10N aqueous ammonia was added dropwise little by little to form a white precipitate. After separating this precipitate by filtration,
A powder was obtained by drying at 120°C for 10 hours. The properties of the obtained powder were examined by X-ray diffraction, differential thermal analysis, and thermogravimetric analysis. Also, add this powder to 400,
The structure of the germanate formed by heating at different temperatures of 600, 800 and 1000 degrees Celsius was confirmed by X-ray diffraction. Table 1 shows the results of X-ray diffraction analysis. From this Table 1, it can be seen that germanate represented by MGeO ₃ has a crystallization temperature of 400°C to 800°C, although the crystallization temperature differs depending on the type of divalent metal such as Ba, Sr, and Mg.
It can be seen that the result is anhydrous at a temperature of . When the particle size of the obtained germanate powder was measured using an electron microscope, it was found to be fine particles of 0.01 to 0.1 μm. As a result of further chemical analysis,
It was a highly pure substance with impurities of 0.1 or less, and its atomic ratio was M/Ge = 0.98 to 1.02.

[Table] (Note) * indicates amorphous.
Example 2 6.7g of high-purity Na metal was taken, added to 67g of dehydrated ethanol and reacted to synthesize sodium ethoxide, and 19.8g of special grade zinc chloride (ZnCl ₂ ) was added thereto and heated under reflux. Zinc ethoxide was obtained. The obtained zinc ethoxide and the germanium isopropoxide obtained in Example 1 are mixed so that the atomic ratio becomes Zn/Ge=2, and the mixture is reacted under reflux at about 80°C.
Then, 15 ml of decarboxylated distilled water was added dropwise little by little while the mixture was being refluxed, and a white precipitate was formed. When this powder was measured in the same manner as in Example 1,
It was found that crystals of Zn ₂ GeO ₄ were obtained. Example 3 Sodium ethoxide is synthesized in the same manner as in Example 2. and special grade lead acetate (Pb( _CH3COO ) ₂ )
Lead ethoxide was obtained by adding 47.1 g and heating under reflux. The obtained lead ethoxide and the germanium isopropoxide obtained in Example 1 are mixed so that the atomic ratio becomes Pb/Ge=1, and the mixture is reacted under reflux at about 80°C.
Then, 15 ml of decarboxylated distilled water was added dropwise little by little while the mixture was being refluxed, and a white precipitate was formed. When this powder was measured in the same manner as in Example 1,
The products shown in Table 2 were obtained.

【table】

Claims (1)

[Scope of Claims] 1. A method for producing a germanate salt, which comprises a step of mixing and reacting a divalent metal alkoxide and a germanium alkoxide, and a step of hydrolyzing the reaction product to obtain a germanate salt. 2. The method for producing a germanate salt according to claim 1, wherein a divalent metal alkoxide and germanium alkoxide are reacted in a state dissolved in an organic solvent. 3. The method for producing a germanate salt according to claim 1 or 2, wherein the reaction temperature of the divalent metal alkoxide and germanium alkoxide is 0°C to 100°C. 4. The method for producing a germanate salt according to any one of claims 1 to 3, wherein the reaction temperature for obtaining the germanate salt by hydrolysis is 0°C to 100°C. 5. The method for producing a germanate salt according to any one of claims 1 to 4, wherein the germanate salt is obtained by hydrolysis with an alkaline aqueous solution. 6 Divalent metals include Ba, Sr, Ca, Mg, Pb, Zn,
The method for producing germanate according to any one of claims 1 to 5, wherein the germanate is one or more metals selected from Co, Mn, Cd, Ni, and Cu. 7. A step of mixing and reacting a divalent metal alkoxide and a germanium alkoxide, a step of hydrolyzing this reaction product to obtain a hydrous germanate and/or an amorphous germanate, and the hydrous germanate. and/or heating an amorphous germanate to obtain an anhydrous and/or crystalline germanate. 8. The method for producing a germanate salt according to claim 7, wherein the heating temperature of the amorphous germanate salt is 400° C. or higher and lower than the decomposition start temperature of the germanate salt.