WO2014156821A1 - Method for producing dimethyl aluminum hydride - Google Patents

Abstract

A method for producing dimethyl aluminum hydride comprises a step of adding an alkali metal hydride to a dimethyl aluminum halide continuously or intermittently at a temperature of 80˚C or higher to react the dimethyl aluminum halide with the alkali metal hydride.

Description

Method for producing dimethylaluminum hydride

The present invention relates to a method for producing dimethylaluminum hydride used for various polymerization reaction catalysts, various synthesis reaction reaction reagents, semiconductor materials, and the like.

In recent years, the demand for dialkylaluminum hydride is increasing as a co-catalyst for polymer polymerization and a reaction reagent in organic synthesis, and further as a raw material for MOCVD (metal organic vapor deposition) for Al (aluminum) wiring in semiconductor manufacturing. .

As a method for producing such a dialkylaluminum hydride, for example, a method of preparing dimethylaluminum hydride by reacting trimethylaluminum with lithium aluminum hydride is known (see, for example, Patent Document 1 and Patent Document 2). .

However, in such a method, generally expensive lithium aluminum hydride is used, the yield of dimethylaluminum hydride is low, and further, it takes a lot of time to process the residue generated by the reaction. In some cases, it may not be industrially satisfactory.

Therefore, for example, as shown in the following formula (1), a method of preparing a dialkylaluminum hydride by reacting a dialkylaluminum halide with an alkali metal hydride is known. In such a method, compared with lithium aluminum hydride, an inexpensive alkali metal hydride is generally used, so that the cost can be reduced and the residue generated in the reaction is mainly halogenated. Because of alkali metal halide salts, post-treatment is easy.
Formula (1):
R ₂ AlX + MH → R ₂ AlH + MX (1)
(In formula (1), R represents an alkyl group, X represents a halogen atom, and M represents an alkali metal.)
As a method for producing such a dialkylaluminum hydride, for example, a method for producing dimethylaluminum hydride in which dimethylaluminum halide is added to an oil slurry of sodium hydride at 30 to 50 ° C. and reacted therewith (for example, Patent Documents) 3) or, for example, in a hexane solvent, sodium hydride and dimethylaluminum chloride are reacted in the presence of a polishing medium such as glass beads (for example, see Patent Document 4). For example, a method for producing diethylaluminum hydride in which diethylaluminum chloride is dropped into a 1.3-diisopropylbenzene solution of sodium hydride and reacted with them has been proposed (see, for example, Patent Document 5).

JP-A-10-96079 JP 2000-072780 A U.S. Pat. No. 2,915,542 JP 2000-256367 A JP 2013-49648 A

However, in the method for producing dimethylaluminum hydride described in Patent Document 3 and Patent Document 4, a by-product may be generated with the progress of the reaction. If it does so, the yield of a dimethylaluminum hydride will fall, and a by-product will adhere in a reactor, and stirring will become difficult. Moreover, in the Example of patent document 5, there is no description of dimethylaluminum hydride, and when a dimethylaluminum hydride is actually manufactured by the method described in patent document 5, a by-product is generated, and the yield of dimethylaluminum hydride is reduced. The same problem arises as it decreases and makes stirring difficult.

Furthermore, in the method for producing dimethylaluminum hydride described in Patent Document 3, it is necessary that the sodium hydride to be used is synthesized by adding metal borate to metal sodium and hydrogen, which facilitates the production process and It is difficult to reduce the manufacturing cost. In addition, in the method for producing dimethylaluminum hydride described in Patent Document 4, sodium hydride and dimethylaluminum chloride are reacted in the presence of a polishing medium such as glass beads. Therefore, a special reactor containing the polishing medium is used. It is necessary to prepare. Therefore, it is difficult to scale up industrially.

Accordingly, an object of the present invention is to provide a method for producing dimethylaluminum hydride, which can suppress the production of by-products and improve the yield, and can further easily produce dimethylaluminum hydride industrially inexpensively. Is to provide.

The method for producing dimethylaluminum hydride according to the present invention comprises a step of continuously or intermittently adding an alkali metal hydride to dimethylaluminum halide at a temperature of 80 ° C. or higher to react the dimethylaluminum halide with the alkali metal hydride. It is characterized by including.

In the present invention, it is preferable that the temperature is in the range of 80 ° C. or higher and 150 ° C. or lower.

In the present invention, it is more preferable that the temperature is in the range of 85 ° C. or higher and 130 ° C. or lower.

In the present invention, it is preferable that dimethylaluminum halide and alkali metal hydride are reacted in a hydrocarbon solvent having a boiling point higher than that of dimethylaluminum hydride to be produced.

In the present invention, it is preferable to include a step of separating and purifying dimethylaluminum hydride by distillation of a reaction mixture obtained by the reaction of dimethylaluminum halide and alkali metal hydride.

In the present invention, it is preferable that the dimethylaluminum halide is dimethylaluminum chloride and the alkali metal hydride is sodium hydride.

According to the method for producing dimethylaluminum hydride of the present invention, alkali metal hydride is continuously or intermittently added to dimethylaluminum halide at a temperature of 80 ° C. or higher to react dimethylaluminum halide with alkali metal hydride. Therefore, the production of by-products can be suppressed, and the yield of dimethylaluminum hydride can be improved.

Further, in the method for producing dimethylaluminum hydride according to the present invention, a general alkali metal hydride and dimethylaluminum halide can be used as raw materials, and there is no need to use a special reactor. Inexpensive and easy to manufacture.

Therefore, dimethylaluminum hydride can be produced inexpensively and easily on an industrial scale, while the production of by-products can be suppressed and the yield can be improved.

The method for producing dimethylaluminum hydride of the present invention includes at least a reaction step of adding an alkali metal hydride to dimethylaluminum halide, and if necessary, a ripening step of reacting raw material components in the reaction mixture, and purifying the reaction mixture. Purification step.
1. Reaction Step In the reaction step, alkali metal hydride (raw material) is continuously or intermittently added to dimethylaluminum halide (raw material) and reacted.

Dimethylaluminum halide is a compound containing an aluminum atom, two methyl groups bonded to the aluminum atom, and a halogen atom bonded to the aluminum atom.

Examples of the halogen atom of dimethylaluminum halide include chlorine, bromine, fluorine, iodine and the like, and preferably chlorine.

Such a dimethylaluminum halide is preferably dimethylaluminum chloride from an economic viewpoint. Moreover, such a dimethylaluminum halide may be used independently and can also be used together.

Such dimethylaluminum halide can be prepared by a known method. For example, dimethylaluminum halide can be easily synthesized from trimethylaluminum and aluminum halide.

The alkali metal hydride is a compound in which a hydrogen atom is bonded to an alkali metal atom, and examples thereof include lithium hydride, sodium hydride, potassium hydride, rubidium hydride, and cesium hydride. Among such alkali metal hydrides, sodium hydride is preferably used from the economical viewpoint. Moreover, such alkali metal hydrides may be used alone or in combination.

The alkali metal hydride may be an industrially available commercial product (for example, trade name: SH manufactured by KAI Kasei Co., Ltd.) or may be purified as necessary.

The addition ratio of the alkali metal hydride is not particularly limited, but is, for example, 1 mol or more, for example, 1.5 mol or less, preferably 1.1 mol or less from an economical viewpoint, with respect to 1 mol of dimethylaluminum halide.

If the addition ratio of the alkali metal hydride is 1 mol or more with respect to 1 mol of dimethylaluminum halide, the residual amount of dimethylaluminum halide in the reaction mixture described later can be reduced, and high purity dimethylaluminum hydride can be obtained. Obtainable.

More specifically, in the reaction step, first, the above dimethylaluminum halide and, if necessary, a solvent are charged into the reactor.

The reactor is not particularly limited, and examples thereof include a known reactor of a vertical type or a horizontal type.

The solvent is not particularly required, but is preferably used from the viewpoint of improving the fluidity of the slurry reaction and removing heat of reaction heat.

The solvent is not particularly limited as long as it is a reaction inert solvent with respect to the raw material and the reaction product, and examples thereof include known solvents such as hydrocarbons. Examples of the hydrocarbons include aliphatic saturated hydrocarbons (eg, heptane, hexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, etc.), aromatic hydrocarbons (toluene, xylene, mesitylene). , Cumene, cymen, tetralin, etc.), liquid paraffin, mineral oil and the like.

Among these solvents, preferably, a solvent having a boiling point or distillation start temperature of 130 ° C. or higher under atmospheric pressure (standard pressure) is mentioned, and from the viewpoint of ease of separation and purification during distillation, Preferably, a solvent having a boiling point higher than that of the dimethylaluminum hydride to be produced (154 ° C.) and a large difference between them is used. Specific examples of the aliphatic saturated hydrocarbons include dodecane (boiling point: 214 to 216 ° C.), tridecane (boiling point: 234 ° C.), tetradecane (boiling point: 253 to 255 ° C.), and aromatic hydrocarbons. Examples of the oil include tetralin (boiling point: 206 to 208 ° C.), and examples of the mineral oil include Daphne Oil KP-15 (distillation start temperature at 10 mmHg: 158 ° C.) manufactured by Idemitsu Kosan Co., Ltd. Moreover, such a solvent may be used independently and can also be used together.

The charge ratio of the solvent is not particularly limited, but is, for example, 10 parts by mass or more, preferably 50 parts by mass or more, for example, 500 parts by mass or less, preferably 300 parts by mass or less with respect to 100 parts by mass of dimethylaluminum halide. More preferably, it is 200 parts by mass or less. If the charging ratio of the solvent is not less than the above lower limit value, the fluidity of the solid content (alkali metal halide) produced in the reaction can be ensured and can be easily stirred.

In addition, when dimethylaluminum halide and a solvent are charged into a reactor, the reactor is heated to a predetermined temperature while stirring with a stirrer.

The stirrer is not particularly limited, and examples thereof include a stirrer having a known stirring blade such as a crescent moon, an anchor, a propeller, a paddle, a turbine type, a max blend type, and a full zone type.

The predetermined temperature is, for example, 80 ° C. or higher, preferably 85 ° C. or higher, for example, 130 ° C. or lower, preferably 125 ° C. or lower, more preferably 120 ° C. or lower.

Next, the above alkali metal hydride is continuously or intermittently added to the reactor charged with dimethylaluminum halide to react the dimethylaluminum halide with the above alkali metal hydride.

The method for adding the alkali metal hydride continuously or intermittently is not particularly limited. For example, a method in which a slurry in which an alkali metal hydride is dispersed in a solvent is added (dropped) continuously or intermittently, And a method of adding alkali metal hydride powder continuously or intermittently.

Among such addition methods, a method in which a slurry in which an alkali metal hydride is dispersed in a solvent is preferably added (dropped) continuously or intermittently.

In this case, first, an alkali metal hydride is dispersed in a solvent to prepare a slurry. Examples of the solvent for preparing the slurry include the same solvents as those described above. Moreover, when the solvent is previously charged to the reactor, it is preferable that the previously charged solvent and the solvent for preparing the slurry are the same.

The content ratio of the alkali metal hydride in such a slurry is, for example, 3 parts by mass or more, preferably 5 parts by mass or more, for example, 50 parts by mass or less, preferably 30 parts by mass with respect to 100 parts by mass of the solvent. It is as follows.

Then, the slurry is dropped into the reactor, for example, while stirring with a stirrer or flowing with an inert gas such as nitrogen.

The addition (dropping) time can be appropriately determined according to the reaction temperature and other conditions, and is, for example, 0.3 hours or more, preferably 0.5 hours or more, for example, 24 hours or less, preferably 10 hours or less.

Further, during the addition (dropping) of the alkali metal hydride, the inside of the reactor is maintained in a predetermined temperature range (hereinafter referred to as reaction temperature), and the raw material components and the reaction product are mixed by the above stirrer. Stir.

The reaction temperature is 80 ° C. or higher, preferably 85 ° C. or higher, more preferably 90 ° C. or higher. The upper limit of the reaction temperature is not particularly limited, but generally 150 ° C. or lower, preferably from the thermal stability of dimethylaluminum hydride. 130 ° C. or lower, more preferably 125 ° C. or lower, particularly preferably 120 ° C. or lower.

When the reaction temperature is 80 ° C. or higher, the reaction rate between dimethylaluminum halide and alkali metal hydride can be improved, and the reaction can be completed with certainty. That is, when the reaction temperature is less than 80 ° C., the reaction rate is slow even if alkali metal hydride is continuously or intermittently added to dimethylaluminum halide, and it is difficult to complete these reactions.

Further, it is preferable that the reaction temperature is 150 ° C. or lower because the generated dimethylaluminum hydride can be prevented from being decomposed by heat.

In addition, such a reaction process is implemented in inert gas (nitrogen gas, argon gas, etc.) atmosphere.

Thus, the reaction process is completed. As a result, as shown in the following formula (2), dimethylaluminum halide and an alkali metal hydride react to produce dimethylaluminum hydride (reaction product).

Formula (2):
Me ₂ AlX + MH → Me ₂ AlH + MX (2)
(In formula (2), Me represents a methyl group, X represents a halogen atom, and M represents an alkali metal.)
2. Ripening step Following the reaction step, preferably an aging step is performed to convert the dimethylaluminum halide remaining in the reaction mixture (raw material and reaction product) into dimethylaluminum hydride. Thereby, the yield and quality of dimethylaluminum hydride can be improved.

More specifically, while stirring the reaction mixture in the reactor with the above stirrer, the temperature is maintained in a predetermined temperature range, and the reaction is performed for a predetermined aging time.

The predetermined temperature range includes, for example, the same temperature range as the reaction temperature described above, and is 80 ° C. or higher, preferably 85 ° C. or higher, more preferably 90 ° C. or higher, and the upper limit temperature is not particularly limited. Is 150 ° C. or lower, preferably 130 ° C. or lower, more preferably 125 ° C. or lower, and particularly preferably 120 ° C. or lower. The predetermined temperature range is preferably the same temperature as the reaction temperature.

The predetermined aging time is, for example, 0.5 hours or more, preferably 1 hour or more, for example, 48 hours or less, preferably 24 hours or less, more preferably 10 hours or less.

Thus, the ripening process is completed.

After the aging step, the conversion rate of dimethylaluminum halide is, for example, 80% or more, preferably 90% or more, and more preferably 100%. The conversion rate can be measured by the method described in Examples described later.

The reaction yield of dimethylaluminum hydride is, for example, 60% or more, preferably 70% or more, and more preferably 80% or more. In addition, reaction yield can be measured by the method as described in the Example mentioned later.
3. Purification step Following the reaction step or aging step, preferably a purification step is performed to purify the reaction mixture. Thereby, high purity dimethylaluminum hydride can be obtained.

The method for purifying the reaction mixture is not particularly limited, and examples thereof include known methods such as distillation, filtration, and decantation. When a solvent is used in the reaction, the method for purifying the reaction mixture is preferably distillation from the viewpoint of separation from the solvent.

Examples of the distillation method include known distillation methods, preferably batch distillation using a distillation column, continuous distillation, and the like. Examples of the distillation tower include known distillation towers such as a packed tower and a plate tower.

When purifying the reaction mixture by distillation, the reaction mixture may be directly distilled, or after solid content such as alkali metal halide produced by the reaction is removed in advance by filtration or decantation, the reaction mixture may be distilled. .

In particular, in the reaction step described above, when a solvent having a boiling point higher than that of dimethylaluminum hydride to be produced is used, it is preferable to directly distill the reaction mixture. This eliminates the need for solvent evaporation and simplifies the production process. Also, since the kettle residue (including solids) after distillation contains the solvent, the kettle residue is fixed to the distillation column. And unity can be suppressed, and the residual liquor can be easily discharged from the distillation column.

That is, if the reaction between dimethylaluminum halide and alkali metal hydride is completed by the above reaction step and / or aging step, high-purity dimethylaluminum hydride can be obtained by simple distillation purification.

The purity of the dimethylaluminum hydride thus obtained is, for example, 90.0% or more, preferably 95.0% or more, and more preferably 99.8% or more.
4). Effects In such a method for producing dimethylaluminum hydride, an alkali metal hydride is continuously or intermittently added to dimethylaluminum halide at a temperature of 80 ° C. or higher in the reaction step.

Thereby, as shown in the above formula (2), the dimethylaluminum halide and the alkali metal hydride react to produce dimethylaluminum hydride.

On the other hand, in the reaction step, when dimethylaluminum halide is continuously or intermittently added to the alkali metal hydride at a temperature of 80 ° C. or higher (see Comparative Example 1 described later), as shown in the following formula (3): The produced dimethylaluminum hydride further reacts with the excessive alkali metal hydride to produce an aluminum complex as a by-product.
Formula (3):
Me ₂ AlH + MH → MAlMe ₂ H ₂ (3)
(In formula (3), Me represents a methyl group, and M represents an alkali metal.)
If it does so, an aluminum complex will adhere in a reactor, and stirring will become difficult and reaction cannot be continued. In addition, the yield of dimethylaluminum hydride is reduced.

On the other hand, when the alkali metal hydride is continuously or intermittently added to dimethylaluminum halide at a temperature of 80 ° C. or higher in the reaction step as in the present invention, the added alkali metal hydride is: Reacts with excess dimethylaluminum halide to produce dimethylaluminum hydride and is consumed.

Therefore, it is possible to suppress the reaction between the added alkali metal hydride and the generated dimethylaluminum hydride, and it is possible to suppress the formation of an aluminum complex as a by-product.

As a result, sticking of by-products to the reactor can be suppressed, and the reaction can be completed with certainty. In addition, the yield can be improved.

Further, in the above method for producing dimethylaluminum hydride, general alkali metal hydride and dimethylaluminum halide can be used as raw materials, and it is not necessary to use a special reactor. Can be manufactured inexpensively and easily.

Next, although this invention is demonstrated based on an Example and a comparative example, this invention is not limited by the following Example. In the examples, parts and percentages indicating the blending ratio are based on mass. Moreover, numerical values, such as a mixture ratio in an Example, can be substituted for the upper limit value or the lower limit value of the corresponding portion described in the above embodiment.
[Example 1]
A well-dried 300 mL glass flask (reactor) equipped with a crescent blade stirrer, thermometer, reflux condenser and dropping funnel, 19.7 parts of dimethylaluminum chloride (dimethylaluminum halide) under a nitrogen atmosphere, mineral oil (Solvent, manufactured by Idemitsu Kosan Co., Ltd., trade name: Daphne Oil KP-15) was charged with 52.2 parts and heated to 120 ° C. with stirring.

Next, 9.2 parts of 60% sodium hydride (alkali metal hydride, manufactured by Kay Kasei Co., Ltd., trade name: SH (white oil impregnated product)) and 65.8 parts of the above mineral oil are added to the dropping funnel. While being charged and flowing the slurry with nitrogen, it was continuously dropped into the reactor at a dropping rate of 1.5 parts / minute for 50 minutes (reaction step). As a result, dimethylaluminum chloride and sodium hydride reacted to produce dimethylaluminum hydride. The reaction temperature in the reactor during the dropping was adjusted to 120 to 125 ° C. The molar ratio of sodium hydride to dimethylaluminum chloride was 1.07.

Thus, a reaction mixture (reaction mixture) containing dimethylaluminum hydride was obtained in the reactor.

After completion of the dropwise addition, the reaction temperature in the reactor was maintained in the temperature range of 128 to 130 ° C., and the reaction mixture was stirred for 1 hour (aging process). Thus, dimethylaluminum chloride remaining in the reaction mixture and sodium hydride were sufficiently reacted (aging reaction).

During the dropping and the ripening reaction, the solid content in the reaction mixture flowed without problems by stirring, and no problem of fixation or consolidation occurred.

After completion of the above stirring, a part of the reaction mixture was extracted and the solid content was removed by filtration to obtain a filtrate. Then, the chlorine concentration in the filtrate was measured, and the conversion rate of dimethylaluminum chloride was calculated by comparing with the chlorine concentration in the dimethylaluminum chloride solution at the start of the reaction (before the start of dropping). The conversion of dimethylaluminum chloride was 90.5%. The chlorine concentration was measured by a potentiometric titration method using a silver nitrate solution, and the conversion rate was obtained by determining the number of moles of dimethylaluminum chloride remaining from the measured chlorine concentration, and assuming that the number of moles of dimethylaluminum chloride before the reaction was 100. Calculated as a percentage.

Further, the aluminum concentration in the filtrate was measured, and the reaction yield of dimethylaluminum hydride was calculated by comparing with the aluminum concentration in the dimethylaluminum chloride solution at the start of the reaction (before the start of dropping). The reaction yield of dimethylaluminum hydride was 79.4%. The aluminum concentration was measured by a chelate titration method using a disodium ethylenediaminetetraacetate (EDTA) solution, and the reaction yield was the remaining dimethylaluminum determined from the chlorine concentration from the number of moles of aluminum calculated from the aluminum concentration. The value obtained by subtracting the number of moles of chloride was calculated as the number of moles of dimethylaluminum hydride produced by the reaction, and the percentage was calculated with the number of moles of dimethylaluminum chloride before the reaction as 100.
[Example 2]
A well-dried 0.5 L glass flask (reactor) equipped with a turbine blade stirrer, thermometer, reflux condenser and dropping funnel was charged with 78.6 parts of dimethylaluminum chloride (dimethylaluminum halide) under a nitrogen atmosphere. , 89.1 parts of the above mineral oil (solvent) were charged and heated to 90 ° C. with stirring.

Next, in a dropping funnel, 36.8 parts of 60% sodium hydride (alkali metal hydride, manufactured by K.I. Kasei Co., Ltd., trade name: SH (white oil impregnated product)) and the above-described mineral oil (solvent) 103.2. Then, the slurry was continuously added dropwise to the reactor at a dropping rate of 3.5 parts / minute for 40 minutes while the slurry was fluidized with nitrogen (reaction process). As a result, dimethylaluminum chloride and sodium hydride reacted to produce dimethylaluminum hydride. The reaction temperature in the reactor during the dropwise addition was adjusted to 88 to 91 ° C. The molar ratio of sodium hydride to dimethylaluminum chloride was 1.07.

Thus, a reaction mixture (reaction mixture) containing dimethylaluminum hydride was obtained in the reactor.

After completion of the dropwise addition, the reaction mixture is stirred for 20 hours while maintaining the reaction temperature in the temperature range of 88 to 91 ° C., and further, while maintaining the reaction temperature in the reactor at 120 ° C. The mixture was stirred for 5 hours (aging process). Thus, dimethylaluminum chloride remaining in the reaction mixture and sodium hydride were sufficiently reacted (aging reaction).

During the dropping and the ripening reaction, the solid content in the reaction solution flowed without problems by stirring, and no problem of fixation or consolidation occurred.

After completion of the above stirring, the conversion rate of dimethylaluminum chloride was calculated in the same manner as in Example 1, and the conversion rate of dimethylaluminum chloride was 98.8%.

Moreover, when the reaction yield of dimethylaluminum hydride was computed similarly to said Example 1, the reaction yield of dimethylaluminum hydride was 84.0%.
[Example 3]
A well-dried 1 L glass flask (reactor) equipped with a Max blend blade stirrer, thermometer, reflux condenser and dropping funnel, under nitrogen atmosphere, 102.2 parts of dimethylaluminum chloride (dimethylaluminum halide), The above mineral oil (solvent) 110.3 parts was charged and heated to 110 ° C. with stirring.

Next, in a dropping funnel, 47.9 parts of 60% sodium hydride (alkali metal hydride, manufactured by Kay Kasei Co., Ltd., trade name: SH (white oil impregnated product)) and the above-described mineral oil (solvent) 137.8 Then, the slurry was continuously added dropwise to the reactor (glass flask) at a dropping rate of 3.7 parts / minute for 50 minutes (reaction process). Thereby, dimethylaluminum chloride and sodium hydride reacted to produce dimethylaluminum hydride (reaction product).

The reaction temperature in the reactor during dropping was adjusted to 110 to 123 ° C. The molar ratio of sodium hydride to dimethylaluminum chloride was 1.07.

Thus, a reaction mixture (reaction mixture) containing dimethylaluminum hydride was obtained in the reactor.

After completion of the dropwise addition, the reaction mixture was stirred for 5 hours while maintaining the reaction temperature in the reactor in the temperature range of 110 to 123 ° C. (aging step). Thus, dimethylaluminum chloride remaining in the reaction mixture and sodium hydride were sufficiently reacted (aging reaction).

During the dropping and the ripening reaction, the solid content in the reaction mixture flowed without problems by stirring, and no problem of fixation or consolidation occurred.

After completion of the stirring, the conversion rate of dimethylaluminum chloride was calculated in the same manner as in Example 1 above. As a result, the conversion rate of dimethylaluminum chloride was 100%.

Further, as in Example 1 above, the reaction yield of dimethylaluminum hydride was calculated, and the reaction yield of dimethylaluminum hydride was 76.0%.

The obtained reaction mixture was transferred to a still as it was without filtration and distilled under reduced pressure, and after cutting off a portion of the initial distillate, dimethylaluminum hydride was obtained with a distillation yield of 75% (purification step). . The purity of the obtained dimethylaluminum hydride was 99.4%. The purity was calculated from the aluminum concentration.

In the distillate, dimethylaluminum chloride had a concentration of less than 0.01% and was not substantially contained. Moreover, the kettle residue after distillation was not fixed to the distiller and could be easily discharged from the distiller.
[Comparative Example 1]
A well-dried 300 mL glass flask equipped with a crescent blade stirrer, thermometer, reflux condenser and dropping funnel, under a nitrogen atmosphere, 9.2 parts of 60% sodium hydride, and 52.2 parts of the above mineral oil The slurry was heated to 120 ° C. with stirring.

Next, 19.7 parts of dimethylaluminum chloride and 65.8 parts of the above mineral oil were charged into the dropping funnel, and the slurry was flowed with nitrogen, and continuously into the reactor at a dropping rate of 1.5 parts / min. Dripped. The reaction temperature in the reactor during the dropping was adjusted to 120 to 125 ° C. The molar ratio of sodium hydride to dimethylaluminum chloride was 1.07.

Ten minutes after the start of dropping, a large solid was formed in the reactor and stirring became difficult, so the reaction was stopped.
[Comparative Example 2]
Mineral oil changed to n-hexane, reaction temperature during dropping of sodium hydride solution changed from 120-125 ° C to 22-40 ° C, reaction temperature during ripening reaction increased from 128-130 ° C to 40 ° C Dimethylaluminum hydride was produced in the same manner as in Example 1, except that the change and the reaction time of the aging reaction were changed from 1 hour to 12 hours. When the conversion rate of dimethylaluminum chloride was calculated in the same manner as described above, the conversion rate of dimethylaluminum chloride was 20.3%.

Next, the reaction solution temperature was heated to 50 ° C., and the reaction was again aged for 6 hours. The conversion rate of dimethylaluminum chloride after the aging reaction was 22.7%.

Next, the temperature of the reaction solution was heated to 60 ° C., and the reaction was aged again for 4 hours. The conversion of dimethylaluminum chloride after this aging reaction was 24.4%. Therefore, it was difficult to complete the reaction in Comparative Example 2.

Although the above invention has been provided as an exemplary embodiment of the present invention, this is merely an example and should not be interpreted in a limited manner. Variations of the present invention that are apparent to one of ordinary skill in the art are within the scope of the following claims.

The present invention is used for production of dimethylaluminum hydride used in various polymerization reaction catalysts, various synthesis reaction reaction reagents and semiconductor materials.

Claims (6)

Dimethylaluminum hydride comprising a step of continuously or intermittently adding an alkali metal hydride to dimethylaluminum halide at a temperature of 80 ° C. or higher to react dimethylaluminum halide with an alkali metal hydride. Manufacturing method. The method for producing dimethylaluminum hydride according to claim 1, wherein the temperature is in the range of 80 ° C to 150 ° C. The method for producing dimethylaluminum hydride according to claim 1, wherein the temperature is in the range of 85 ° C to 130 ° C. The method for producing dimethylaluminum hydride according to claim 1, wherein dimethylaluminum halide and alkali metal hydride are reacted in a hydrocarbon solvent having a boiling point higher than that of dimethylaluminum hydride. The method for producing dimethylaluminum hydride according to claim 1, comprising a step of separating and purifying dimethylaluminum hydride by distillation of a reaction mixture obtained by the reaction of dimethylaluminum halide and alkali metal hydride. Method. Dimethylaluminum halide is dimethylaluminum chloride,
The method for producing dimethylaluminum hydride according to claim 1, wherein the alkali metal hydride is sodium hydride.