JP7744264B2 - Trimethylaluminum-containing composition and method for producing the same - Google Patents

Description

The present invention relates to a trimethylaluminum-containing composition and a method for producing the same.

Trimethylaluminum (hereinafter sometimes referred to as TMAL) is used as a polymerization catalyst, a raw material for olefin production, and a raw material for the electronics industry, such as semiconductors, and there is demand for high-purity products with low impurity content. The main impurities contained in trimethylaluminum are chlorine-containing components such as dimethylaluminum chloride, oxygen-containing components, ethyl group-containing components, and organosilicon components. Several methods are known for reducing the impurities contained in trimethylaluminum.

Known methods include removing impurities contained in trimethylaluminum by distillation and evaporation, and mixing impurity-containing trimethylaluminum with metallic sodium in a solvent, and then removing the solvent by distillation (Patent Document 1). This method is said to provide trimethylaluminum with reduced amounts of organosilicon components, chlorine components, etc.

As a method for reducing oxygen-containing impurities in alkylaluminum, it has been disclosed that trimethylaluminum is reacted with lithium aluminum hydride, followed by distillation, to provide purified trimethylaluminum with an oxygen concentration reduced to less than 2 ppm (Patent Document 2, Example 2).

Japanese Patent Application Laid-Open No. 2006-1896 Japanese Patent Application Publication No. 2-67230

The impurity reduction method described in Patent Document 1 has the following problems.
(1) Metallic sodium that is substantially free of impurities (purity of 99.9% or more) is required, and it is necessary to add the sodium to the vessel while dissolving it in a solvent whose boiling point is at least 10° C. higher than that of trimethylaluminum, which increases costs and makes the operation complicated.
(2) The amount of metallic sodium required is 2 to 5 wt % based on the amount of trimethylaluminum, which is costly and requires complicated post-treatment of the reaction residue.
(3) The chlorine content of the raw material TMAL is specified to be 50 to 100 ppm, and no further reduction of the chlorine content is anticipated.

The method described in Example 2 of Patent Document 2 can reduce the concentration of oxygen components to <2 ppm. However, the inventors' studies have revealed that the resulting purified trimethylaluminum contains a large amount (approximately 4,120 ppm) of dimethylaluminum hydride, which remains in the trimethylaluminum even after distillation purification (see Comparative Example 3). A new issue has emerged: dimethylaluminum hydride may behave differently from trimethylaluminum when trimethylaluminum is used as a manufacturing raw material for the electronics industry or as a polymerization catalyst. Furthermore, the inventors' studies have revealed that the method described in Example 2 of Patent Document 2 can reduce not only oxygen components but also chlorine-containing components, but that the reduction in oxygen and chlorine-containing components results in the inclusion of a large amount of dimethylaluminum hydride (see Comparative Example 3).

The present invention therefore aims to provide a trimethylaluminum-containing composition in which the amounts of dimethylaluminum chloride and dimethylaluminum hydride, which are the main causes of inhibiting the function of trimethylaluminum when used as a manufacturing raw material in the electronics industry or as a polymerization catalyst, have been reduced to a level that does not inhibit or is unlikely to inhibit the function of trimethylaluminum.

In Example 2 of Patent Document 2, the amount of lithium aluminum hydride added to the trimethylaluminum is approximately 5 wt%. There is no mention of the concentrations of oxygen-containing or chlorine-containing components in the trimethylaluminum to be purified, but a large excess amount is used relative to the components to be reduced. In Example 2 of Patent Document 2, the target for reduction is oxygen-containing components, and it is presumed that a large excess amount was used to reduce these to <2 ppm. As a result, although not stated in Patent Document 2, it is presumed that approximately 4,120 ppm of dimethylaluminum hydride was contained in the trimethylaluminum.

As a result of further investigations, the inventors discovered that by using the same lithium aluminum hydride as in Example 2 of Patent Document 2 to produce trimethylaluminum containing oxygen-containing and chlorine-containing components as impurities, but by significantly reducing the amount and using milder reaction conditions, it was possible to obtain purified trimethylaluminum in which, although the oxygen-containing components could not be significantly reduced, the chlorine-containing components could be reduced to a level that prevented the inhibition of the activity of trimethylaluminum, and the dimethylaluminum hydride content could also be reduced to a level that prevented the inhibition of the activity of trimethylaluminum, thereby completing the present invention.

As shown in the results of the Examples, the method of the present invention fails to substantially reduce oxygen-containing components. In the description of Example 2 of Patent Document 2, the target to be reduced is oxygen components, and a person skilled in the art would not be motivated to conceive of the present invention, which corresponds to a purification method under conditions that fail to substantially reduce oxygen components.

The present invention is as follows.
[1]
A composition containing trimethylaluminum, dimethylaluminum chloride, and dimethylaluminum hydride,
The content of dimethylaluminum hydride is in the range of 0.1 ppm or more and 500 ppm or less in terms of hydrogen atom mass, and the content of dimethylaluminum chloride is 15 ppm or less in terms of chlorine atom mass.
The composition.
[2]
The composition according to [1], further comprising an oxygen-containing component, wherein the content of the oxygen-containing component is 5 ppm or more and 500 ppm or less in terms of oxygen atomic mass.
[3]
The composition according to [1] or [2], which is substantially free of ethyl group-containing components.
[4]
[The composition according to any one of [1] to [3], wherein the content of the organosilicon component is 0.01 ppm or more and 1 ppm or less in terms of silicon atomic mass.
[5]
The calcium content is 0.1 ppm or less in terms of calcium atomic mass, the cadmium content is 0.1 ppm or less in terms of cadmium atomic mass, the cobalt content is 0.1 ppm or less in terms of cobalt atomic mass, the chromium content is 0.1 ppm or less in terms of chromium atomic mass, the copper content is 0.1 ppm or less in terms of copper atomic mass, the iron content is 0.1 ppm or less in terms of iron atomic mass, the germanium content is 0.6 ppm or less in terms of germanium atomic mass, and the lithium content is 0.1 ppm or less in terms of lithium atomic mass. the magnesium content is 0.1 ppm or less in terms of magnesium atomic mass; the manganese content is 0.1 ppm or less in terms of manganese atomic mass; the sodium content is 0.1 ppm or less in terms of sodium atomic mass; the nickel content is 0.1 ppm or less in terms of nickel atomic mass; the lead content is 5 ppm or less in terms of lead atomic mass; the tin content is 2 ppm or less in terms of tin atomic mass; or the zinc content is 0.1 ppm or less in terms of zinc atomic mass.
[6]
A step (1) of mixing a raw material trimethylaluminum containing dimethylaluminum chloride as an impurity with a compound represented by general formula (A);
wherein M ^I represents a Group 1 element, M ^II represents a Group 13 element, and R represents a combination of hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a cyano group; and the method includes a step (2) of distilling the mixture obtained by the mixing to obtain the composition according to [1] as a main fraction,
the amount of the compound represented by formula (A) mixed in step (1) is in the range of 1 equivalent or more and 20 equivalents or less relative to dimethylaluminum chloride;
A method for producing a composition containing trimethylaluminum, dimethylaluminum chloride, and dimethylaluminum hydride.
[7]
The production method according to [6], wherein the starting trimethylaluminum further contains an oxygen-containing component, and the composition obtained as the main fraction in step (2) further contains an oxygen-containing component, and the content of the oxygen-containing component is 5 ppm or more and 500 ppm or less in terms of oxygen atomic mass.
[8]
The production method according to [6] or [7], wherein the starting trimethylaluminum further contains an ethyl group-containing component, and the composition obtained as the main fraction in step (2) is substantially free of the ethyl group-containing component.
[9]
The production method according to any one of [6] to [8], wherein the mixture obtained in step (1) is filtered to remove solids, and the resulting liquid is subjected to distillation in step (2).
[10]
The method according to any one of [6] to [9], wherein the Group 13 element is aluminum or boron.
[11]
The method according to any one of [6] to [10], wherein the compound represented by general formula (A) is lithium aluminum hydride or sodium borohydride.
[12]
[12] The method according to any one of [6] to [11], wherein the mixing temperature in step (1) is 20°C or higher and 150°C or lower.

According to the present invention, it is possible to obtain a trimethylaluminum-containing composition, which is purified trimethylaluminum, in which the content of chlorine-containing components has been reduced to a level that prevents the inhibition of the activity of trimethylaluminum, and the content of dimethylaluminum hydride has also been reduced to a level that prevents the inhibition of the activity of trimethylaluminum.

<TMAL-containing composition>
The TMAL-containing composition of the present invention is a composition containing trimethylaluminum, dimethylaluminum chloride, and dimethylaluminum hydride,
The content of dimethylaluminum hydride is in the range of 0.1 ppm to 500 ppm in terms of the mass of hydrogen atoms, and the content of dimethylaluminum chloride is 15 ppm or less in terms of the mass of chlorine atoms.

The TMAL-containing composition of the present invention is primarily composed of trimethylaluminum (TMAL), and contains dimethylaluminum chloride and dimethylaluminum hydride as impurities. It may also contain impurities other than dimethylaluminum chloride and dimethylaluminum hydride, but the remainder is TMAL.

The dimethylaluminum hydride content, calculated as the mass of hydrogen atoms contained in dimethylaluminum hydride, is in the range of 0.1 ppm to 500 ppm, preferably 0.1 ppm to 300 ppm, more preferably 0.1 ppm to 200 ppm, even more preferably 0.1 ppm to 150 ppm, and even more preferably 0.1 ppm to 100 ppm. Dimethylaluminum hydride is a by-product produced when preparing the TMAL-containing composition of the present invention, and the lower the dimethylaluminum hydride content, the less likely it is to inhibit the activity of TMAL when the TMAL-containing composition is used as a manufacturing raw material for the electronics industry, a polymerization catalyst, or the like.

The dimethylaluminum chloride content is 15 ppm or less, calculated as the mass of chlorine atoms contained in dimethylaluminum chloride. The lower the dimethylaluminum chloride content, the less likely it is to inhibit the activity of TMAL when the TMAL-containing composition is used as a manufacturing raw material for the electronics industry, a polymerization catalyst, or the like. Dimethylaluminum chloride is a component contained as an impurity in the raw material TMAL, and is a component that is reduced when preparing the TMAL-containing composition of the present invention.

The TMAL-containing composition of the present invention may further contain oxygen-containing components as impurities. When an oxygen-containing component is contained, the content of the oxygen-containing component can be 5 ppm or more and 500 ppm or less in terms of the mass of oxygen atoms contained in the oxygen-containing component. The oxygen-containing component is an organoaluminum compound, including alkoxides, and is contained in and derived from the raw material TMAL. When preparing the TMAL-containing composition of the present invention, depending on the conditions, the amount of the oxygen-containing component may be reduced compared to the raw material, but it is not significantly reduced, and a certain amount may remain.

The TMAL-containing composition of the present invention preferably is substantially free of ethyl group-containing components. Ethyl group-containing components are organoaluminum compounds such as triethylaluminum, which may be contained in the raw material TMAL and are components derived from the raw material TMAL. When preparing the TMAL-containing composition of the present invention, the amount of these components is reduced compared to the raw material.

The TMAL-containing composition of the present invention may contain, in addition to the above, metal-containing components derived from the raw material TMAL as impurities. A low content of these impurities is advantageous when the TMAL-containing composition is used as a manufacturing raw material for the electronics industry or as a polymerization catalyst. The content of the organosilicon component, calculated as the mass of silicon atoms contained in the organosilicon component, can be 0.01 ppm or more and 1 ppm or less, preferably 0.2 ppm or less, and more preferably 0.1 ppm or less.

The calcium content is 0.1 ppm or less in terms of calcium atomic mass, the cadmium content is 0.1 ppm or less in terms of cadmium atomic mass, the cobalt content is 0.1 ppm or less in terms of cobalt atomic mass, the chromium content is 0.1 ppm or less in terms of chromium atomic mass, the copper content is 0.1 ppm or less in terms of copper atomic mass, the iron content is 0.1 ppm or less in terms of iron atomic mass, the germanium content is 0.6 ppm or less in terms of germanium atomic mass, and the lithium content is 0.1 ppm or less in terms of lithium atomic mass. The content of the magnesium component is 0.1 ppm or less in terms of the atomic mass of magnesium, the content of the manganese component is 0.1 ppm or less in terms of the atomic mass of manganese, the content of the sodium component is 0.1 ppm or less in terms of the atomic mass of sodium, the content of the nickel component is 0.1 ppm or less in terms of the atomic mass of nickel, the content of the lead component is 5 ppm or less in terms of the atomic mass of lead, the content of the tin component is 2 ppm or less in terms of the atomic mass of tin, or the content of the zinc component is 0.1 ppm or less in terms of the atomic mass of zinc. Preferably, the contents of all of the metal components as impurities are within the above numerical ranges.

<Method of producing TMAL-containing composition>
The method for producing the TMAL-containing composition of the present invention includes the steps of: (1) mixing a starting material trimethylaluminum containing dimethylaluminum chloride as an impurity with a compound represented by general formula (A); and (2) distilling the mixture obtained by the mixing to obtain the TMAL-containing composition of the present invention as a main fraction.

Process (1)
In step (1), a raw material trimethylaluminum (raw material TMAL) containing dimethylaluminum chloride as an impurity is mixed with a compound represented by general formula (A).

In general formula (A), M ^I represents an element of Group 1, M ^II represents an element of Group 13, and R represents any combination of hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a cyano group.

Specific examples of M ^I (Group 1 element) include lithium, sodium, and potassium, and specific examples of M ^II (Group 13 element) include boron and aluminum.

Specific examples of alkyl groups having 1 to 6 carbon atoms represented by R in the compound represented by general formula (A) include methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, i-butyl, and t-butyl. Specific examples of alkoxy groups having 1 to 6 carbon atoms include methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, s-butoxy, i-butoxy, t-butoxy, methoxymethoxy, methoxyethoxy, ethoxyethoxy, and acetoxy.

The three functional groups R in the compound represented by general formula (A) may be the same or different.

From the viewpoint of ease of availability, the compound represented by general formula (A) is preferably lithium aluminum hydride, sodium bis(2-methoxyethoxy)aluminum hydride, sodium borohydride, lithium borohydride, sodium cyanoborohydride, or lithium triethylborohydride, with lithium aluminum hydride or sodium borohydride being more preferred.

The compound represented by general formula (A) can be a commercially available product or a product produced by a known method, or a product prepared as a solution in a hydrocarbon solvent can also be used.

The amount of the compound represented by general formula (A) mixed in step (1) is in the range of 1 to 20 equivalents relative to the dimethylaluminum chloride. Using an amount of 1 or more equivalents relative to the dimethylaluminum chloride contained in the raw material TMAL will achieve the desired effect of reducing dimethylaluminum chloride. On the other hand, using too much of the compound represented by general formula (A) undesirably increases the amount of dimethylaluminum hydride by-product. For these reasons, the amount of the compound represented by general formula (A) mixed is preferably 1 to 20 equivalents relative to the dimethylaluminum chloride, more preferably 2 to 15 equivalents.

There are no particular restrictions on the TMAL used as a raw material, but while this varies depending on the production method and conditions, TMAL may generally contain impurities derived from raw materials, solvents, and operations, such as chlorine components such as dimethylaluminum chloride in the range of 1 ppm to 1000 ppm, organosilicon components in the range of 1 ppm to 1000 ppm, metal-containing components in the total range of 0.1 ppm to 100 ppm, hydrocarbon components other than those derived from trimethylaluminum in the range of 1 ppm to 1000 ppm, and oxygen components in the range of 1 ppm to 1000 ppm.

The compound represented by general formula (A) reacts with dimethylaluminum chloride, which is contained as an impurity in the raw material TMAL, to undergo the reaction represented by the following general formula (1).

Furthermore, the reaction shown in the following general formula (2) also occurs with the main component, trimethylaluminum.

If an excess amount of the compound represented by general formula (A) is used, the side reaction represented by general formula (2) will occur, causing an increase in the amount of dimethylaluminum hydride produced as a by-product in the resulting TMAL-containing composition.

The reaction apparatus used in step (1) may be either vertical or horizontal, and can be used without any particular restrictions. For example, a pressure-resistant autoclave equipped with a stirrer can be used. Conventional stirring blades can be used, such as propellers, turbines, Pfaudle, Maxblend, and Fullzone.

The reactor is preferably kept under an inert gas atmosphere such as nitrogen or argon, as moisture in the air will react with the reaction system.

The reaction temperature should be above the melting point of trimethylaluminum, 15°C, and is preferably between 20°C and 150°C. There are no particular restrictions on the reaction time, but it is preferably between 1 hour and 48 hours. The reaction pressure may be either atmospheric pressure or pressurized, but is preferably between 0 MPaG and 0.2 MPaG.

The mixture obtained in step (1) can be filtered to remove solids, and the resulting liquid can be subjected to distillation in step (2). Filtration can be performed on the reaction mixture after the above reaction to remove solids including unreacted reducing agent. In particular, when lithium aluminum hydride is used as the reducing agent, filtration is preferred because it can reduce the dimethylaluminum hydride content in the composition obtained after distillation.

It is preferable to perform the filtration under an inert gas atmosphere such as nitrogen or argon, as moisture in the air will react with the reaction mixture.

As the reaction mixture reacts with the moisture contained in the filter paper, it is preferable to use a glass filter that does not require filter paper and to use a vacuum pump for suction.

There are no particular restrictions on the pressure used during filtration, but a pressure of 50 kPaA or less is preferred. The filtration temperature should be above the melting point of trimethylaluminum, 15°C, and is preferably between 20°C and 30°C.

Process (2)
In step (2), the mixture obtained by mixing in step (1) or the mixture after subsequent filtration is distilled to obtain the TMAL-containing composition of the present invention as a main fraction. In the distillation, a first fraction and a main fraction are obtained as fractions, and the main fraction is the TMAL-containing composition of the present invention.

To improve separation performance, it is preferable to use packing in the distillation column. The packing can be commercially available or manufactured by known methods, and either structured or irregular packing can be used. The higher the number of theoretical plates, the better, but an industrially advantageous height should be selected. A distillation column with a theoretical plate count of 4 to 20 is preferred.

Because moisture in the air inside the distillation apparatus will react with the reaction mixture or filtrate, it is preferable to replace the air with an inert gas such as nitrogen or argon before starting the distillation.

The temperature during distillation depends on the degree of vacuum in the apparatus, but is preferably 40°C or higher and 150°C or lower, and more preferably 40°C or higher and 130°C or lower. The pressure during distillation may be either atmospheric pressure or reduced pressure, but is preferably 0.01 kPaA or higher and 30 kPaA or lower.

Of the fractions obtained by distillation, the initial fraction is primarily composed of trimethylaluminum, but also contains many impurities. Therefore, it is difficult to obtain it as the composition of the present invention, but it can be recovered and reused in the reduction reaction or distillation of the next batch.

Of the fractions obtained by distillation, the recovery rate of the main fraction is preferably, for example, 30% or more and 70% or less.

The TMAL-containing composition obtained as the main fraction has a dimethylaluminum hydride content in the range of 0.1 ppm to 500 ppm, calculated as hydrogen atom mass, and a dimethylaluminum chloride content of 15 ppm or less, calculated as chlorine atom mass. The TMAL-containing composition obtained as the main fraction may further contain an oxygen-containing component, and the content of the oxygen-containing component may be 5 ppm to 500 ppm, calculated as oxygen atom mass. It is preferable that the TMAL-containing composition obtained as the main fraction is substantially free of ethyl group-containing components.

The present invention will be described in more detail below based on examples. However, these examples are merely illustrative of the present invention, and the present invention is not intended to be limited to these examples. The following analytical method was used to analyze the components of trimethylaluminum.

Preparation of analytical sample: A solution of trimethylaluminum, the target of analysis, diluted with an organic solvent was dropped into an acidic aqueous solution to prepare a trimethylaluminum hydrolyzed solution. The hydrogen and hydrocarbon components were diluted approximately four-fold with liquid paraffin, and the metal components (including aluminum), chlorine components, and organosilicon components were diluted approximately 30-fold with xylene.

Analysis Method 1 (Metallic Components Excluding Aluminum and Organosilicon Components)
For the metal components other than aluminum contained in trimethylaluminum, the aqueous layer of the hydrolyzed solution was measured using an ICP-AES (inductively coupled plasma-atomic emission spectroscopy) analyzer OPTIMA 7300DV manufactured by PerkinElmer, and the mass equivalent content of each metal atom was calculated. For the organosilicon components, the organic layer of the hydrolyzed solution was measured using an ICP-AES analyzer ICP-7510 manufactured by Shimadzu Corporation, and the mass equivalent content of silicon atoms was calculated.

Analysis method 2 (aluminum component)
The aluminum component contained in trimethylaluminum was calculated by titrating aluminum ions contained in the aqueous layer of the hydrolyzed solution using an automatic potentiometric titrator AT-610 manufactured by Kyoto Electronics Manufacturing Co., Ltd., and calculating the content of aluminum atoms converted into mass.

Analysis method 3 (chlorine components)
The chlorine component contained in trimethylaluminum was determined by suspending the aqueous layer of the hydrolyzed solution in an aqueous silver nitrate solution, measuring the absorbance with a spectrophotometer U-1900 manufactured by Hitachi High-Technologies Corporation, and calculating the mass-equivalent content of chlorine atoms contained in trimethylaluminum.

Analysis Method 4 (Hydrogen Components and Hydrocarbon Components)
The hydrogen and hydrocarbon components contained in trimethylaluminum were determined by collecting the gas generated by hydrolysis during the preparation of the above-mentioned analytical sample, measuring the gas composition using a Shimadzu Gas Chromatograph GC-8A, and calculating the contents of these components in trimethylaluminum from the measurement results.

Analysis Method 5 (Oxygen Components)
The oxygen component contained in trimethylaluminum was determined by diluting the trimethylaluminum with deuterated benzene containing anisole added as an internal standard substance, and then measuring the proton NMR with a JEOL Ltd. NMR (nuclear magnetic resonance) apparatus JNM-ECA 500, to calculate the mass-converted content of oxygen atoms.

Example 1
To a nitrogen-purged 1-L SUS autoclave equipped with a stirrer, 197 g (2.74 mol) of the raw material trimethylaluminum containing 400 ppm (78.9 mg) of dimethylaluminum chloride in terms of chlorine atomic mass, and 1.35 g (28.5 mmol, Fujifilm Wako Pure Chemical Industries, purity 80%, 13 equivalents relative to dimethylaluminum chloride) of lithium aluminum hydride were added and stirred for 12 hours at 60° C. Then, using a glass distillation column connected to the autoclave and packed with packing (Sulzer EX Labopacking, manufactured by Sulzer) with 10 theoretical plates, distillation was carried out under conditions of 8 kPaA, 60° C., and a reflux ratio of 20. After distilling off 21 g (0.290 mol) of the initial fraction, 115 g (1.59 mol, yield 58%) of a trimethylaluminum composition was obtained as the main fraction, containing dimethylaluminum chloride at a concentration of 15 ppm or less, calculated as chlorine atom mass, and dimethylaluminum hydride at a concentration of 140 ppm, calculated as hydrogen atom mass. The impurity contents of this composition are shown in Table 1.

Example 2
The same procedure as in Example 1 was repeated except that the amount of lithium aluminum hydride was changed to 8 equivalents relative to the amount of dimethylaluminum chloride. The analytical results of the obtained composition are shown in Table 1.

Example 3
The reaction time was changed to 6 hours in Example 2. After the reaction, the reaction mixture was removed from the reactor and filtered through a glass filter connected to an oil rotary vacuum pump to remove solids. The filtrate was then returned to the reactor and distilled in the same manner as in Example 1 to obtain a trimethylaluminum composition. The analytical results of the composition are shown in Table 1.

Example 4
The same procedures as in Example 1 were carried out except that lithium aluminum hydride was replaced with sodium borohydride (manufactured by Tokyo Chemical Industry Co., Ltd., purity 95%) and the reaction temperature was changed to 100° C. The analytical results of the obtained composition are shown in Table 1.

Comparative Example 1
The starting trimethylaluminum was distilled directly under the same conditions as in Example 1, without adding, mixing, or stirring lithium aluminum hydride. The resulting composition contained 200 ppm of dimethylaluminum chloride, calculated as the mass of chlorine atoms. Other analytical results are shown in Table 1.

Comparative Example 2
The same procedure as in Example 1 was repeated, except that lithium aluminum hydride was replaced with sodium hydride (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., purity 63%, containing mineral oil). The resulting composition was trimethylaluminum containing less than 15 ppm of dimethylaluminum chloride, calculated as chlorine atom mass, and 10 ppm of dimethylaluminum hydride, calculated as hydrogen atom mass, but ethyl group-containing components derived from the starting trimethylaluminum remained. Other analytical results are shown in Table 1.

Comparative Example 3
In accordance with Example 2 of Patent Document 2, lithium aluminum hydride (80% purity, 144 equivalents relative to dimethylaluminum chloride) was used in an amount of 6 wt % relative to the starting trimethylaluminum, and the reaction temperature was changed to 100°C, the reaction time to 1 hour, the distillation pressure to 26.5 kPaA, and the distillation temperature to 80°C, with the other conditions being the same as in Example 1. The resulting composition contained 15 ppm or less of dimethylaluminum chloride in terms of chlorine atomic mass, but 4120 ppm of dimethylaluminum hydride in terms of hydrogen atomic mass. Other analytical results are shown in Table 1.

The present invention is useful in the technical field of trimethylaluminum.

Claims (12)

A composition containing trimethylaluminum, dimethylaluminum chloride, and dimethylaluminum hydride,
The composition has a dimethylaluminum hydride content in the range of 0.1 ppm to 500 ppm in terms of hydrogen atom mass, and a dimethylaluminum chloride content in the range of 15 ppm or less in terms of chlorine atom mass. The composition of claim 1, further comprising an oxygen-containing component, the content of which is 5 ppm or more and 500 ppm or less in terms of oxygen atomic mass. The composition of claim 1 or 2, which is substantially free of ethyl group-containing components. The composition according to any one of claims 1 to 3, wherein the content of the organosilicon component is 0.01 ppm or more and 1 ppm or less, calculated as silicon atomic mass. The calcium content is 0.1 ppm or less in terms of calcium atomic mass; the cadmium content is 0.1 ppm or less in terms of cadmium atomic mass; the cobalt content is 0.1 ppm or less in terms of cobalt atomic mass; the chromium content is 0.1 ppm or less in terms of chromium atomic mass; the copper content is 0.1 ppm or less in terms of copper atomic mass; the iron content is 0.1 ppm or less in terms of iron atomic mass; the germanium content is 0.6 ppm or less in terms of germanium atomic mass; and the lithium content is 0.1 ppm or less in terms of lithium atomic mass. The composition according to any one of claims 1 to 4, wherein the magnesium content is 0.1 ppm or less in terms of magnesium atomic mass, the manganese content is 0.1 ppm or less in terms of manganese atomic mass, the sodium content is 0.1 ppm or less in terms of sodium atomic mass, the nickel content is 0.1 ppm or less in terms of nickel atomic mass, the lead content is 5 ppm or less in terms of lead atomic mass, the tin content is 2 ppm or less in terms of tin atomic mass, or the zinc content is 0.1 ppm or less in terms of zinc atomic mass. A step (1) of mixing a raw material trimethylaluminum containing dimethylaluminum chloride as an impurity with a compound represented by general formula (A);
wherein M ^I represents a Group 1 element, M ^II represents a Group 13 element, and R represents any combination of hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a cyano group; and (2) distilling the mixture obtained by the mixing to obtain the composition according to claim 1 as a main fraction,
the amount of the compound represented by formula (A) mixed in step (1) is in the range of 1 equivalent or more and 20 equivalents or less relative to dimethylaluminum chloride;
A method for producing a composition containing trimethylaluminum, dimethylaluminum chloride, and dimethylaluminum hydride. The production method described in claim 6, wherein the starting trimethylaluminum further contains an oxygen-containing component, and the composition obtained as the main fraction in step (2) further contains an oxygen-containing component, and the content of the oxygen-containing component is 5 ppm or more and 500 ppm or less in terms of oxygen atomic mass. The production method described in claim 6 or 7, wherein the starting trimethylaluminum further contains an ethyl group-containing component, and the composition obtained as the main fraction in step (2) is substantially free of ethyl group-containing components. The manufacturing method described in any one of claims 6 to 8, wherein the mixture obtained in step (1) is filtered to remove solids, and the resulting liquid is subjected to distillation in step (2). The manufacturing method described in any one of claims 6 to 9, wherein the Group 13 element is aluminum or boron. The manufacturing method described in any one of claims 6 to 10, wherein the compound represented by general formula (A) is lithium aluminum hydride or sodium borohydride. The manufacturing method described in any one of claims 6 to 11, wherein the mixing temperature in step (1) is 20°C or higher and 150°C or lower.