JPH0158194B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for purifying organometallic compounds.
More specifically, the present invention relates to a method for removing trace amounts of impurity elements from organometallic compounds. Hereinafter, the organometallic compound will be described using an organoaluminum compound as a representative example. However, it is clear that the method of the present invention is not limited thereto. Organoaluminum compounds are useful substances as polymerization catalysts, raw materials for producing olefins, raw materials for higher alcohols, raw materials for producing high-purity alumina, and the like. However, ordinary organoaluminum compounds contain trace amounts of titanium, vanadium, chromium, manganese,
Elements or metal compounds (hereinafter referred to as impurities) such as iron, cobalt, nickel, copper, uranium, and silicon are present. Impurities in this organoaluminum compound may be extracted from the aluminum raw material for the synthesis of the organoaluminum compound, extracted from the reactor material, or added to additives to accelerate the reaction during the synthesis reaction of the organoaluminum compound. Therefore, it exists. The presence of impurities in organoaluminum compounds brings about various disadvantages for each of the above-mentioned applications. For example, when olefin is produced by polymerizing a small amount of ethylene in the presence of a catalytic amount of an alkyl aluminum compound, undesired polymer by-products may be produced, or when ethylene is added to an alkyl aluminum compound to perform a growth reaction. In addition, there are disadvantages such as elimination of olefin, which inhibits the growth reaction, and inability to produce high-purity aluminum hydroxide or alumina when producing aluminum hydroxide or alumina by hydrolyzing organoaluminum compounds. will occur. Methods such as precision distillation can easily be considered as a method for removing the above-mentioned impurities in organoaluminum compounds, but in this case, it is essentially difficult to purify and recover products that require three nines or higher purity. . This is because the impurities present in the organoaluminum compound are organometallic compounds having the same organic groups as the organoaluminum compound, and therefore have similar boiling point ranges. Also,
This method also has the disadvantage that the equipment is complex and expensive. Under such circumstances, the present inventors conducted intensive research to find an industrial method for highly efficiently removing trace amounts of impurities in organometallic compounds, and as a result, they found that they contain impurities such as those described above. When an organometallic compound is first hydrolyzed (hereinafter referred to as reaction) under specific conditions and then distilled, an unpredictable behavior occurs in which impurities in the organometallic compound are concentrated in the reaction product. They discovered this and completed the present invention. It is an object of the present invention to provide a new process for obtaining organometallic compounds that are substantially to completely free of impurities. That is, the present invention provides a general formula containing at least one impurity of titanium, iron, copper, silicon, sodium, and uranium in a liquid state.

[Formula] or

[Formula] [In the formula, M ₃ is Al, Ga, In or Y, M ₄ is Si,
Ti or Zr, R ₁ , R ₂ , R ₃ and R ₄ are the same or different alkyl, alkoxy or hydrogen atoms (however,
(excluding cases where R ₁ , R ₂ , R ₃ and R ₄ are all hydrogen atoms)] is hydrolyzed to about 0.1 to 50% of the organometallic compound under stirring conditions, The present invention provides a method for purifying an organometallic compound by producing a solid reaction product, then separating the solid reaction product and unreacted organometallic compound by distillation, and recovering the organometallic compound. The organometallic compound to be treated in the method of the invention is an organometallic compound containing at least one metal impurity other than the mother liquor-forming metal. Such impurities include metals or metal compounds other than the metals forming the mother liquor, and organic compounds containing at least one impurity such as titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, aluminum, gallium, or uranium. It exhibits a remarkable effect on the removal of these impurities from metal compounds. Although the concentration of impurities in the organometallic compound is not a limiting factor in the purification process according to the method of the present invention,
Usually, an ultra-high purity organometallic compound with an impurity concentration of about 0.01% by weight or less can be obtained from a raw organometallic compound with an impurity concentration of about 0.5% by weight or less. The organometallic compound mentioned above has the general formula

[Formula] or

[Formula] [In the formula, M ₃ is Al, Ga, In or Y, M ₄ is Si,
Ti or Zr, R ₁ , R ₂ , R ₃ and R ₄ are the same or different alkyl, alkoxy or hydrogen atoms (however,
(excluding cases where R ₁ , R ₂ , R ₃ and R ₄ are all hydrogen atoms)] Preferably an alkyl group having 1 to 12 carbon atoms or a carbon number 1 of a metal element such as Al, Ga, In, Si, Zr, Sn, etc.
Organometallic compounds having ~8 alkoxy groups are targeted for treatment. Especially triethylaluminum, tripropylaluminum, tributylaluminum, trihexylaluminum, dibutylaluminum hydride, dihexylaluminum hydride,
Dioctylaluminium hydride, triethoxyaluminum, tripropoxyaluminum, tributoxyaluminum, and triamyloxyaluminum are preferably used. Further, in the purification treatment of the method of the present invention, the impurity-containing organometallic compound can be subjected to the purification treatment alone, but it is also possible to use it as a mixture with an organic solvent. Such organic solvents include pentane, hexane,
Saturated aliphatic hydrocarbons such as octane, decane, dodecane, paraffin oil, and kerosene; unsaturated aliphatic hydrocarbons such as pentene, hexene, heptene, octene, decene, and dodecene; alicyclic hydrocarbons such as cyclohexane and cyclopentane; Aromatic hydrocarbons such as benzene and toluene, alcohols such as methanol, ethanol, propanol and butanol, and ethers such as diethyl ether, dipropyl ether, anisole, dioxane and tetrahydrofuran can be used. The method of the present invention uses an organometallic compound containing impurities as described above in a liquid state (not only an organometallic compound that is liquid at room temperature, but also a solution in which an organometallic compound that is liquid at room temperature or solid at room temperature is mixed in a solvent). ) and about 0.1 to 50% of the organometallic compound is hydrolyzed under stirring conditions. It is essential that this reaction be carried out under stirring conditions while keeping the organometallic compound in a liquid state. Stirring conditions can be easily determined through preliminary experiments.
Usually, it is sufficient to rotate the stirring blade at 10 to 200 rpm. When the above reaction is kept in a liquid state and carried out under stirring conditions, a reaction of impurities occurs at the same time as the reaction of the organometallic compound. After carrying out the reaction, the unreacted organometallic compound is essentially to completely free of impurities, and the impurities become present in the solid reaction product. However, even if the mixture is kept in a liquid state, impurities cannot be substantially removed unless it is stirred because local reactions occur. Water, steam, acidic aqueous solution, etc. are usually used as the reactant. Water, acidic aqueous solutions, etc. are preferably supplied in the form of organic solvents, but of course they can also be supplied as they are. In the purification process of the present invention, the amount of the reactant used is generally about 0.1 to
The amount used is such that 50%, preferably about 1-20%, is hydrolyzed. Reaction rate of organometallic compound is 0.1%
If the amount is smaller, the removal rate of impurities will decrease,
On the other hand, if the amount is more than 50%, the removal rate is good, but it is not economical, so it is not preferable. The reaction conditions may be carried out at a temperature of about 0 to 150°C. Further, any method of contacting the impurity-containing organometallic compound and the reactant may be used, but a method in which the reactant is added to a state where the organometallic compound is stirred is usually suitably applied. However, other stirring methods such as gas injection mixing are also possible, and addition methods such as feeding into the liquid are also applicable. After the reaction, the organometallic compound is left as it is, or if necessary, the reaction product is separated by standing, filtering, centrifugation, etc., and then subjected to a distillation treatment. In implementing the method of the present invention, the organometallic compound prepurified as described above is subjected to distillation treatments such as simple distillation, precision distillation, and vacuum distillation. The distillation method may be appropriately selected depending on the purity of the target organometallic compound, and the distillation temperature may also be determined depending on the physical properties of the organometallic compound to be purified. Generally, distillation treatment is carried out under a reduced pressure of 0.1 to 100 mmHg at 50
It is desirable to use a temperature range of ~250°C. Distillation treatment is therefore an essential step in the purification method of the present invention, and impurities cannot be effectively removed unless such distillation treatment is performed. Therefore, the method of the present invention is effective for removing impurities from organometallic compounds containing impurities of several percent or less, but the method of the present invention is particularly effective for removing impurities from organometallic compounds containing impurities of 1 to 1000 ppm. It is suitable for producing organometallic compounds of extremely high purity, for example, three nines or more. According to the method of the present invention described in detail above, impurities can be substantially to completely removed from an impurity-containing organometallic compound, and the organometallic compound thus purified can be used as a polymerization catalyst, a raw material for producing olefins, a raw material for producing higher alcohols, It can be effectively used as a raw material for producing pure metal oxides without causing the above-mentioned disadvantages, and its industrial value is great. Hereinafter, the method of the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded. Example 1 570 g of triethylaluminum containing various impurities at the concentrations shown in the raw material column of Table 1 was charged into a No. 5 reactor equipped with a stirrer, a condenser, a water dropping tube, etc., and the mixture was heated while maintaining the temperature at 65°C. While stirring at 100rpm
18 g of water diluted with 1000 c.c. of tetrahydrofuran
was fed over 1 hour to hydrolyze triethylaluminum. The resulting reaction product was separated and removed by filtration, and then tetrahydrofuran was removed by heating at 70°C, followed by vacuum distillation at 97°C and 10 mmHg to obtain 490 g of purified triethylaluminum. The concentrations of various impurity elements in the purified triethylaluminum obtained were as shown in the purified organometallic compound column of Table 1.

[Table] Example 2 In the same reactor as in Example 1, 992 g of triisobutylaluminum containing various impurities at the concentrations shown in the raw material column of Table 2 and tetrahydrofuran were added.
1000 c.c. was charged, and while stirring at 100 rpm while maintaining the temperature at 65° C., 1.8 g of water diluted with 100 c.c. of tetrahydrofuran was fed over 1 hour to hydrolyze triisobutylaluminum. The obtained reaction product was separated and removed by filtration, and then heated at 70°C.
After heating and removing tetrahydrofuran with
The product was distilled under reduced pressure under conditions of Hg and 85°C to obtain 850 g of purified triisobutylaluminum. The concentrations of various impurity elements in the purified triisobutylaluminum obtained were as shown in Table 2.

[Table] Example 3 Using the same reactor as in Example 1, 1020 g of aluminum isopropoxide and isopropanol were prepared.
Pour 1500c.c. and raise the temperature to 80℃ while stirring at 100rpm.
C., water diluted with 200 c.c. of isopropanol in the amount shown in Table 3 was fed over 1 hour to hydrolyze aluminum isopropoxide. The resulting reaction product was separated and removed by filtration, and then the isopropanol was removed by heating at 90°C, followed by vacuum distillation at 135°C and 10 mmHg to obtain about 940 g of purified aluminum isopropoxide. The concentrations of various impurity elements in the purified aluminum isopropoxide obtained were as shown in the purified organometallic compound column of Table 3.

[Table] From the above results, it is clear that impurities in the raw materials can be effectively removed by hydrolyzing approximately 0.1% or more of the raw materials. Example 4 Using the same reactor as in Example 1, 1422 g of titanium isopropoxide and 1500 c.c. of isopropanol were prepared.
was charged, and while stirring at 100 rpm and maintaining the temperature at 80°C, 9 g of water diluted with 200 c.c. of isopropanol was supplied over 1 hour to hydrolyze titanium isopropoxide. The resulting reaction product was separated and removed by filtration, and then the isopropanol was removed by heating at 90°C, followed by distillation under reduced pressure at 116°C at 10 mmHg to obtain purified titanium isopropoxide.
Obtained 1280g. The concentrations of various impurity elements in the purified titanium isopropoxide obtained were as shown in the purified organometallic compound column of Table 4.

[Table] Example 5 100 g of an organometallic compound containing impurities at a concentration as shown in the raw material organometallic compound column of Table 5 was charged into a reactor equipped with a stirrer, a condenser, a water dropping tube, etc. It was diluted with 300 g of the solvent shown in the solvent column. Next, while maintaining the temperature shown in the hydrolysis column and stirring at 100 rpm, water diluted with 200 g of the solvent shown in the hydrolysis column was supplied over 1 hour. (bubbling and supplying as saturated steam), the organometallic compound was decomposed to the hydrolysis rate shown in the hydrolysis column of Table 5. The obtained reaction product is separated and removed by filtration,
Next, the solvent was removed under the conditions shown in Table 5, followed by further distillation to obtain a purified organic metal. The concentrations of various impurity elements in the purified organometallic compound obtained were as shown in the purified organometallic compound column of Table 5.

【table】

【table】

Claims (1)

[Claims] 1. Titanium, iron, copper, silicon, in a liquid state,
At least 1 sodium and uranium impurity
General formula [formula] or [formula] containing species [where M ₃ is Al, Ga, In or Y, M ₄ is Si,
Ti or Zr, R ₁ , R ₂ , R ₃ and R ₄ are the same or different alkyl, alkoxy or hydrogen atoms (however,
0.1 to 50% _{of the} organometallic compound is hydrolyzed under stirring conditions _to solidify _it . producing a reaction product, then separating the reaction product and unreacted organometallic compound by distillation,
A method for purifying an organometallic compound, the method comprising recovering the organometallic compound. 2. The method for purifying an organometallic compound according to claim 1, wherein the hydrolysis of the organometallic compound is 1 to 20%. 3. The method for purifying an organometallic compound according to claims 1 to 2, wherein the hydrolysis reaction is carried out at a temperature of 0 to 150°C. 4. A method for purifying an organometallic compound according to claims 1 to 3, characterized in that the reaction product is subjected to solid-liquid separation treatment before being subjected to distillation.