JPH056556B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing tungsten penta-alkoxide, which is suitable for producing low-temperature sintered dielectric materials and is represented by the general formula. W(OR) ₅ ... (In the formula, R represents an alkyl group. The same applies hereinafter.) More specifically, the present invention relates to a method for producing tungsten penta-alkoxide using tungsten hexachloride as a starting material. [Prior Art] Conventionally, tungsten 5-ethoxide (chemical formula: W(OC ₂ H ₅ ) ₅ ) in which the alkyl group R of tungsten 5-alkoxide is an ethyl group has been produced.
is known to be synthesized by adding sodium ethoxide to a solution of tungsten pentachloride dissolved in ethanol and reacting it (Inorganic Chemistry 1980, Vol. 9, No. 827).
page). [Problems to be solved by the invention] However, the starting material used in this synthesis method, 5-yen tungsten, is extremely difficult to synthesize and expensive, and moreover, it is easily decomposed by moisture, oxygen, etc. in the air. However, there have been problems in that it is difficult to handle and the yield and purity of tungsten penta-alkoxide obtained with this tungsten pentachloride are low. The purpose of the present invention is to have easy synthesis and stability;
Moreover, by using inexpensive starting materials, high-purity tungsten 5 can be produced at low cost and with good yield.
The object of the present invention is to provide a method for producing alkoxides. [Means for Solving the Problems] The present inventors have discovered that when 6-yen tungsten, which is easier to synthesize than tungsten pentachloride, is relatively stable in the air, and is available at a lower price, is dissolved in ethanol. Conventional _{technology ( Inorganic Chemistry 1965 , Inorganic} Chemistry, ₁₉₆₅ ,
(Volume 4, page 1668), they have completed the present invention. That is, in the present invention, tungsten hexachloride is used as a starting material, tungsten hexachloride is dissolved in alcohol to produce tungsten trichloride dialkoxide, and an alcoholic solution of tungsten trichloride dialkoxide and an alcoholic solution of alkali metal alkoxide or an alkali are prepared. High purity tungsten 5 alkoxide is obtained by reacting with an alcohol solution of earth metal alkoxide to obtain an alcohol solution of tungsten 5 alkoxide, and further replacing the solvent of this tungsten 5 alkoxide from alcohol with an aromatic hydrocarbon compound. It is. Note that in this specification, "alkoxide" refers to a compound in which the hydrogen element of the OH group of an alcohol is replaced with a metal element. To obtain tungsten penta-alkoxide, an alcohol solution of tungsten trichloride di-alkoxide described above and an alkali metal alkoxide represented by the following general formula A (OR)... (where A is an alkali metal such as lithium, sodium, potassium, etc.) are used. ) or an alkaline earth metal alkoxide represented by the general formula B (OR) ₂ ... (in the formula, B represents an alkaline earth metal such as magnesium, calcium, strontium, barium, etc.). , respectively, as shown in the reaction formula or WCl ₃ (OR) ₂ +3AOR→W(OR) ₅ +3ACl...WCl ₃ (OR) ₂ +3/2B(OR) ₂ →W(OR) ₅ +3/2BCl... An alcoholic solution of tungsten 5 alkoxide and a chloride of an alkali metal or alkaline earth metal are obtained.The by-product chloride is removed by filtration or centrifugation to obtain an alcoholic solution of tungsten 5 alkoxide as a liquid.This solution includes Since a small amount of alkali metal chloride or alkaline earth metal chloride is still dissolved, this solution is evaporated to dryness.Then, an aromatic hydrocarbon compound is added to the residue as a solvent for dissolving tungsten-5 alkoxide. , chlorides of alkali metals or chlorides of alkaline earth metals precipitate. This precipitate can be removed by filtration or centrifugation to obtain an aromatic hydrocarbon solution of tungsten-5 alkoxide. Isolated, pure tungsten penta-alkoxide can be obtained by evaporating an aromatic hydrocarbon solution, but this compound is extremely sensitive to moisture and susceptible to hydrolysis, so it is usually more convenient to store it in solution. The dissolution of tungsten hexachloride in alcohol is preferably carried out at 0°C or lower to prevent side reactions.In addition, the reaction between tungsten trichloride dialkoxide and each alcohol solution of alkali metal alkoxide or alkaline earth metal alkoxide is It is preferable to reflux at the boiling point of the alcohol because the yield is good and the reaction rate is fast.In addition, in the reaction formula or, the alkali metal alkoxide or alkaline earth metal alkoxide to be added is not the same as hydrogen chloride or chlorine produced by the reaction formula. Since it reacts, it is preferable to add it in excess of the theoretical amount required by the reaction formula or the amount to be added in excess.The amount to be added in excess may be selected from the range of 1.7 to 1.9 times the theoretical amount.If it is less than 1.7 times, is not preferable because unreacted tungsten trichloride dialkoxide remains and if it exceeds 1.9 times, the amount of by-products increases. The aromatic hydrocarbon compound used as the solvent for dissolving the tungsten penta-alkoxide mentioned above is benzene,
Toluene, xylene, etc. are suitable, but benzene with high solubility is most suitable. The tungsten-5 alkoxide obtained by the above-mentioned series of operations can be produced by converting the alcohol into one of the industrially widely used alcohols such as ethanol, methanol, and 2-propanol. Synthesized into 5-isopropoxide, etc. As a result of chemical analysis, the obtained tungsten-5 alkoxide was a highly pure substance with impurities of 0.5% or less. Further, the proportions of the constituent tungsten atoms, carbon atoms, hydrogen atoms, and oxygen atoms were extremely close to the stoichiometric ratio. [Effects of the Invention] As described above, according to the present invention, a solution in which tungsten hexachloride is dissolved in alcohol is reacted with an alcohol solution of an alkali metal alkoxide or an alkaline earth metal alkoxide, and the alcohol is converted into an aromatic Substitution with group hydrocarbon compounds has the excellent effect of producing highly pure tungsten penta-alkoxide with easy synthetic operations and low cost with good yield. [Examples] Next, in order to show specific embodiments of the present invention, the present invention will be explained in more detail using Examples. However, the examples shown below are merely examples, and the technical scope of the present invention is not limited thereby. It's not something you do. Example 1 Put 2000 ml of dehydrated methanol into a 5000 ml round bottom flask and cool it to -5°C, then gradually add 200 g of tungsten hexachloride and dissolve by stirring for 2 hours to form a methanol solution of tungsten trichloride dimethoxide. I got it. A methanol solution of magnesium methoxide obtained by reacting 32 g of highly pure magnesium metal with 2000 ml of dehydrated methanol was added to this tungsten trichloride dimethoxide. The amount of magnesium methoxide added was 1.7 times the theoretical reaction amount. Methanol solutions of tungsten trichloride dimethoxide and magnesium methoxide were refluxed and reacted at the boiling point for 4 hours to obtain a methanol solution of tungsten dimethoxide. Since a small amount of magnesium chloride was still dissolved in this solution, methanol was evaporated from the solution using an evaporator at 60°C for 1 hour, and the dissolved substance was dried. 2000 ml of benzene was added to the evaporated residue of this solution, and magnesium chloride was precipitated as a precipitate insoluble in benzene. This benzene solution was filtered to separate it from the precipitate to obtain a benzene solution of tungsten 5-methoxide as a liquid. Benzene was evaporated from this solution using an evaporator at 40° C. for 3 hours to obtain 137 g of tungsten 5-methoxide. The yield was 80.2%. As a result of chemical analysis of this substance, the purity was 99.6% or more, and the constituent elements were very close to the theoretical values as shown in the table. Example 2 High purity metallic sodium was used instead of the methanol solution of magnesium methoxide used in Example 1.
A methanol solution of sodium methoxide obtained by reacting 60 g with 2000 ml of dehydrated methanol was used. The amount of sodium methoxide added to tungsten trichloride dimethoxide was 1.7 times the theoretical reaction amount. Thereafter, 145 g of dungsten 5-methoxide was obtained in the same manner as in Example 1. The yield was 85.2%. As a result of chemical analysis of this substance, the purity was 99.7% or more, and the constituent elements were very close to the theoretical values as shown in the table. Example 3 Put 2000 ml of dehydrated ethanol into a 5000 ml round bottom flask, cool it to -78°C, then gradually add 200 g of tungsten hexachloride and dissolve by stirring for 4 hours to form an ethanol solution of tungsten trichloride diethoxide. I got it. To this solution was added an ethanol solution of sodium ethoxide obtained by reacting 60 g of high purity metal sodium weighed in a dry box with 2000 ml of dehydrated ethanol. The amount of sodium ethoxide added was 1.7 times the theoretical reaction amount. Ethanol solutions of tungsten trichloride 2-ethoxide and sodium ethoxide were refluxed at the boiling point for 6 hours to react, thereby obtaining an ethanol solution of tungsten 5-ethoxide. Since a small amount of sodium chloride was still dissolved in this solution, the ethanol was evaporated from the solution using an evaporator at 50° C. for 1.5 hours, and the dissolved material was dried. 2000 ml of benzene was added to the evaporated residue of this solution, and sodium chloride was precipitated as a precipitate insoluble in benzene. This benzene solution was filtered to separate it from the precipitate to obtain a benzene solution of tungsten 5-ethoxide as a liquid. Benzene was evaporated from this solution using an evaporator at 40° C. for 3 hours to obtain 183 g of tungsten 5-ethoxide. The yield was 88.7%. Chemical analysis of this substance revealed that the purity was over 99.8%, and the constituent elements were very close to the theoretical values as shown in the table. 【table】

Claims (1)

[Claims] 1. Tungsten hexachloride is dissolved in alcohol to produce tungsten trichloride dialkoxide, and an alcoholic solution of the tungsten trichloride dialkoxide and an alcoholic solution of an alkali metal alkoxide or an alkaline earth metal alkoxide are combined. A method for producing tungsten 5 alkoxide, which comprises: reacting to produce an alcohol solution of tungsten 5 alkoxide, and replacing alcohol, which is a solvent for the tungsten 5 alkoxide, with an aromatic hydrocarbon compound to obtain tungsten 5 alkoxide. 2. The method for producing tungsten penta-alkoxide according to claim 1, wherein the reaction amount of the alkali metal alkoxide or alkaline earth metal alkoxide with the tungsten trichloride dialkoxide is in excess of the theoretical reaction amount. 3 Alcohols include methanol, ethanol, 2-
The method for producing tungsten 5-alkoxide according to claim 1 or 2, wherein the alcohol is one alcohol selected from propanol. 4. The method for producing tungsten 5-alkoxide according to any one of claims 1 to 3, wherein the alkali metal alkoxide is one alkali metal alkoxide selected from lithium alkoxide, sodium alkoxide, and potassium alkoxide. 5. Tungsten according to any one of claims 1 to 3, wherein the alkaline earth metal alkoxide is one alkaline earth metal alkoxide selected from magnesium alkoxide, calcium alkoxide, strontium alkoxide, and barium alkoxide. Method for producing alkoxide.