JP2013087114A - Method for producing silicon compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a silicon compound by which a desired silicon compound can be produced in high efficiency and high yield by reducing a compound having a silicon-halogen bond.SOLUTION: The method for producing the silicon compound includes reducing the compound having a silicon-halogen bond by using an alkali metal alkoxyaluminum hydride. In a preferable embodiment of the invention, the reduction is carried out in a hydrocarbon-based solvent, and the compound having the silicon-halogen bond has a structure obtained by bonding one silicon atom with at least one halogen atom and another silicon atom. Further, in a preferable embodiment of the invention, the silicon-halogen bond is converted to a silicon-hydrogen bond by the reduction.

Description

  The present invention relates to a method for producing a silicon compound by reduction.

  Conventionally, in a reaction using a general reducing agent, ether solvents such as diethyl ether and tetrahydrofuran have been widely used from the viewpoint of the solubility of the reducing agent and the reaction rate. In particular, lithium aluminum hydride (LAH), which can exhibit good reactivity as a hydride reducing agent when reducing halogen atoms to hydrogen atoms, has extremely low solubility in solvents other than ether solvents, and is reduced using LAH. Solvents that can be used for the reaction were substantially limited to ether solvents only. Moreover, since the solubility of LAH is low even when an ether solvent is used, the reduction reaction using LAH is generally performed in a heterogeneous system. For example, in Patent Document 1, a salt containing a dianion of tetradecachlorocyclohexasilane prepared from trichlorosilane and a tertiary polyamine is brought into contact with lithium aluminum hydride in diethyl ether, whereby the chlorine atom of the dianion is changed. It has been reported that cyclohexasilane reduced to hydrogen atoms can be produced.

Japanese Patent No. 4519955

  However, when a halogen atom bonded to a silicon atom is reduced to a hydrogen atom in an ether solvent as in the reduction of the tetradecachlorocyclohexasilane dianion in Patent Document 1, the silicon-hydrogen bond that is a reduction product is reduced. The yield of the compound (in the case of Patent Document 1, cyclohexasilane) sometimes did not reach the desired level.

  The present invention has been made paying attention to the circumstances as described above, and its purpose is to obtain a desired silicon hydride compound with high efficiency and high yield by reducing a compound having a silicon-halogen bond. An object of the present invention is to provide a method for producing a silicon compound.

  As a result of intensive studies to solve the above problems, the inventors of the present invention reduced the yield of a reduction product (a compound having a silicon-hydrogen bond) when a compound having a silicon-halogen bond was reduced. It was found that the reduction reaction was caused by a heterogeneous system. Based on this knowledge, it is possible to express the same reactivity as conventional LAH in reducing halogen atoms on silicon atoms to hydrogen atoms, and it is highly soluble in solvents and can be reduced in a homogeneous system. In order to find a reducing agent that can be used, various reducing agents were investigated. As a result, it was found that if the alkali metal hydride is an alkali metal hydride, the reduction reaction can be carried out in a homogeneous system, and the halogen atom on the silicon atom can be replaced with a hydrogen atom with good reactivity. By using an alkali metal salt, it was confirmed that a desired reduction product was obtained with high efficiency and high yield, and the present invention was completed.

  That is, the method for producing a silicon compound of the present invention is characterized in that a compound having a silicon-halogen bond is reduced using an alkali aluminum hydride alkali metal salt. In a preferred embodiment of the present invention, the reduction is preferably performed in a hydrocarbon solvent, and the compound having a silicon-halogen bond has at least one halogen atom and another silicon atom in one silicon atom. It preferably has a structure formed by bonding. In a preferred embodiment of the present invention, the silicon-halogen bond is converted to a silicon-hydrogen bond by the reduction.

  According to the present invention, since an alkali aluminum hydride alkali metal salt is used as a reducing agent, it is possible to perform a reduction reaction in a homogeneous system, and as a result, an improvement in reaction rate when reducing a compound having a silicon-halogen bond. Can be achieved. Thereby, it becomes possible to obtain a desired silicon hydride compound with high efficiency and high yield by reducing a compound having a silicon-halogen bond. Furthermore, the alkali aluminum hydride alkali metal salt has an advantage that it is highly stable in air and easy to handle as compared with LAH which is a typical hydride reducing agent.

  In the present invention, a silicon hydride compound is produced by reducing a compound having a silicon-halogen bond using an alkali aluminum hydride alkali metal salt.

  The compound having a silicon-halogen bond may be any compound having at least one silicon-halogen bond in one molecule, but preferably has two or more silicon-halogen bonds. Examples of the halogen in the silicon-halogen bond include a chlorine atom, a bromine atom, a fluorine atom, and an iodine atom, and a chlorine atom is preferable.

  The number of silicon atoms constituting the compound having a silicon-halogen bond may be one like (mono-, di-, tri-, tetra-) halogenated monosilane, or two or more. Also good. When there are two or more silicon atoms, each silicon atom may be connected in a straight chain like (mono-, di-, tri-) halogenated disilane, or halogenated tris (trialkylsilyl) silane. It may be connected like a branch. When there are 3 or more silicon atoms, each silicon atom may form a halogenated cyclic silane skeleton such as halogenated cyclopentasilane or halogenated cyclohexasilane. Further, the compound having a silicon-halogen bond may be an ionic compound (salt) or a complex salt such as a salt containing a dianion of tetradecachlorocyclohexasilane of Patent Document 1.

  Further, the compound having a silicon-halogen bond is a structure in which at least one halogen atom and another silicon atom are bonded to one silicon atom (hereinafter also referred to as “Si—Si—X structure”), For example, -Si-SiXn- (wherein X represents a halogen atom, n is 1 or 2, and when n = 2, the two Xs may be the same or different. It is preferable that it has a structure as shown by this. When such a compound having a Si—Si—X structure is reduced, it has a structure represented by —Si—SiH—, but the —Si—Si— bond is oxidized to form a siloxane bond (—Si—). O-Si-) is easily converted. Therefore, in the case of reducing halogen bonded to at least one Si forming a Si-Si bond, such as the compound having the Si-Si-X structure, the target product, i.e., -Si-SiH- is shown. The yield of the silicon compound having a structure tends to decrease. However, in the present invention, the target silicon compound (reduction product) can be obtained with high efficiency and high yield even in such a case. That is, the effect of the present invention becomes more significant in the embodiment in which the compound having a silicon-halogen bond for reduction has the Si-Si-X structure.

  The compound having a silicon-halogen bond is preferably composed only of a silicon atom and a halogen atom, but the halogen may be substituted with a hydrogen atom or may be substituted with another substituent. . Examples of the substituent include an alkyl group having 1 to 20 carbon atoms (methyl group, ethyl group, propyl group, butyl group, etc.), an aryl group having 6 to 20 carbon atoms (phenyl group, naphthyl group, etc.), and the like. . These substituents are usually bonded to a silicon atom.

  Preferable examples of the compound having a silicon-halogen bond as described above include, for example, trimethylchlorosilane, diphenyldichlorosilane, methyltrichlorosilane, phenyltrichlorosilane, trichlorosilane, tetrachlorosilane (mono-, di-, tri- Tetra-) halogenated monosilanes; chloro (trimethylsilyl) dimethylsilane, 1,2-dichlorotetramethyldisilane, 1,1-dichlorotetramethyldisilane, 1,1,2-trichlorotrimethyldisilane, etc. (mono-, di- , Tri-, tetra-) halogenated disilanes; halogenated tris (trialkylsilyl) silanes such as chlorotris (trimethylsilyl) silane, chlorotris (triethylsilyl) silane; decachlorocyclopentasilane, dodecachlorocyclohexane Ionic compounds of salts including tetradecanol chloro cyclohexasilane dianion or complex; halogenated cyclic silane such Sashiran the like.

  In the present invention, an alkali aluminum hydride alkali metal salt is used as a reducing agent. Alkoxy aluminum hydride alkali metal salt is an anion formed by bonding (coordinating) n (n is an integer of 1 to 3, particularly 1 or 2) hydride and (4-n) alkoxide centering on aluminum. And a salt of an alkali metal cation. Here, the alkoxide is preferably an alkoxide having 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, particularly 3 to 5 carbon atoms, and specifically, for example, methoxide, ethoxide, 2-methoxyethoxide. , Tert-butoxide and the like. Moreover, the alkali metal which becomes a counter ion of an anion is sodium, potassium, lithium etc., for example.

  Preferable examples of the alkali metal hydride alkali metal salt include, for example, sodium bis (2-methoxyethoxy) aluminum hydride, lithium tri-tert-butoxyaluminum hydride and the like, and among these, availability is easy. In view of the above, sodium bis (2-methoxyethoxy) aluminum hydride is preferable.

  What is necessary is just to set the usage-amount of the alkali aluminum hydride alkali metal salt used as the said reducing agent suitably according to the kind etc. of reaction substrate (compound which has a silicon-halogen bond). Theoretically, hydrogen per mole of compound (1 / m) having a silicon-halogen bond (where m means the number of Si-halogen bonds per molecule of the compound having a silicon-halogen bond). The alkoxyaluminum alkali metal salt may be (1 / n) mol or more (where n means the number of aluminum-hydrogen bonds per molecule of the alkoxyalkoxyaluminum alkali metal salt), but preferably ( 2 / n) to (50 / n) mol, more preferably (5 / n) to (40 / n) mol, and even more preferably (10 / n) to (30 / n) mol. is there. If the amount of the reducing agent used is too large, the post-treatment takes time and the productivity tends to decrease. On the other hand, if it is too small, the yield tends to decrease.

In the present invention, an alkoxyaluminum hydride alkali metal salt is used as the reducing agent, so that the solvent that can be used is not limited to the ether solvent as in the conventional reduction reaction using LAH. It is also possible to use a solvent.
The solvent used for the reduction reaction in the present invention is not particularly limited as long as it does not react with a hydride reducing agent. Examples of such a solvent include aromatic hydrocarbon solvents such as benzene and toluene; pentane and hexane. And aliphatic hydrocarbon solvents such as heptane and methylcyclohexane; ether solvents such as diethyl ether, tetrahydrofuran, cyclopentyl methyl ether, diisopropyl ether and methyl tertiary butyl ether; Among these, solvents other than ether solvents, specifically, hydrocarbon solvents (aromatic hydrocarbon solvents and aliphatic hydrocarbon solvents) are preferable, and aromatic hydrocarbon solvents are particularly preferable. By using a solvent other than the ether solvent, the desired silicon hydride compound can be obtained with higher efficiency and yield. That is, when an ether solvent is used, a peroxide is by-produced due to the ether solvent, and the target reduction product (compound having a silicon-hydrogen bond) is oxidized by the peroxide, and as a result. Although there is concern about a decrease in yield, such a decrease in yield can be avoided by using a solvent other than an ether solvent such as a hydrocarbon solvent, and the reaction efficiency and reaction yield can be further improved. . These solvents are preferably subjected to purification such as distillation or dehydration before the reaction in order to remove water and dissolved oxygen contained therein. The solvent used for the reduction reaction may be used alone or in combination of two or more.

  The amount of the solvent used for the reduction reaction is preferably adjusted so that the concentration of the reaction substrate (compound having a silicon-halogen bond) is 5 mol / L or less, more preferably 4 mol / L or less. The concentration is 3 mol / L or less. When the concentration of the reaction substrate is higher than the above range, that is, when the amount of the solvent used is too small, the heat generated by the reaction cannot be sufficiently removed and the reaction product may be hardly dissolved. On the other hand, the upper limit of the amount of solvent used for the reduction reaction is not particularly limited, but is preferably adjusted so that the concentration of the reaction substrate is 0.01 mol / L or more, more preferably 0.02 mol / L or more. A more preferable concentration is 0.03 mol / L or more. When the concentration of the reaction substrate is lower than the above range, that is, when the amount of the solvent used is larger than the above range, the reaction rate tends to decrease, and the reduction product is removed from the reaction solution after the reduction reaction by distilling off the solvent. Productivity tends to decrease when trying to recover.

  The reduction can be performed by bringing a reaction substrate (a compound having a silicon-halogen bond) into contact with a reducing agent (alkoxyaluminum hydride alkali metal salt). The contact between the reaction substrate and the reducing agent is preferably performed in the presence of a solvent. In order to bring the reaction substrate and the reducing agent into contact with each other in the presence of a solvent, for example, 1) one of the reaction substrate and the reducing agent is dissolved or dispersed in the solvent to form a solution or dispersion and mixed with the other (the other 2) Add the solution or dispersion to the other, or add the solution or dispersion to the other) 2) Dissolve or disperse both in a solvent and leave it as a solution or dispersion, and then mix them together 3) Solvent What is necessary is just to employ | adopt mixing procedures, such as adding a reaction substrate and a reducing agent simultaneously or sequentially in it. Among these, the embodiment 2) is particularly preferable.

  Further, at the time of contact between the reaction substrate and the reducing agent, it is preferable to drop at least one of the reaction substrate and the reducing agent (that is, one or both) into the reaction system in which the reduction is performed. By dropping one or both of the reaction substrate and the reducing agent in this way, the heat generated by the reduction reaction can be controlled by the dropping speed, etc. An effect leading to improvement is obtained. When one is dropped, the other may be charged into the reaction system (reactor) with a solvent or alone (no solvent). When both are dropped, only the solvent may be charged in the reaction system (reactor) in advance, or the reaction substrate and the reducing agent may be dropped simultaneously or sequentially into an empty reactor. . In any case, it is preferable that the side (reaction substrate and / or reducing agent) to be dropped is dissolved or dispersed in a solvent and dropped as a solution or dispersion.

  Preferred embodiments when one or both of the reaction substrate and the reducing agent are added dropwise include the following three embodiments. That is, A) An embodiment in which a solution or dispersion of a reaction substrate is charged in an anti-container, and a solution or dispersion of a reducing agent is added dropwise thereto, and B) A solution or dispersion of a reducing agent is charged in a reactor. In this mode, the reaction substrate solution or dispersion is dropped into the reactor, and C) the reaction substrate solution or dispersion and the reducing agent solution or dispersion are dropped simultaneously or sequentially into the reactor. Among these, the aspect of A) is preferable.

When one or both of the reaction substrate and the reducing agent are added dropwise in the above-described embodiments A) to C), the solute concentration in the solution or dispersion containing the reaction substrate as a solute is preferably 0.01 mol / L or more, more preferably. Is 0.02 mol / L or more, more preferably 0.04 mol / L or more, and particularly preferably 0.05 mol / L or more. If the solute concentration is too low, productivity tends to decrease. On the other hand, the upper limit of the solute concentration in the solution or dispersion containing the reaction substrate as a solute is preferably 5 mol / L or less, more preferably 4 mol / L or less, and further preferably 3 mol / L or less. If the solute concentration (particularly the solute concentration of the solution or dispersion used for the dropping) is too high, it tends to be difficult to control the heat generation in the reduction reaction.
In addition, it is preferable that the solute concentration of each solution or dispersion is set so that the amount of the solvent of the solution or dispersion using the reaction substrate as the solute and the solution or dispersion using the reducing agent as the solute are approximately the same. .

The reaction temperature during the reduction may be appropriately set according to the kind of the reaction substrate and the reducing agent, and is usually −20 ° C. to 150 ° C., preferably −10 ° C. or higher, more preferably 0 ° C. or higher, preferably 100 ° C. Hereinafter, it is more preferably 80 ° C. or less, and further preferably 70 ° C. or less. The reaction time may be appropriately determined according to the progress of the reaction, but is usually 10 minutes or longer and 72 hours or shorter, preferably 30 minutes or longer and 48 hours or shorter, more preferably 1 hour or longer and 24 hours or shorter.
In general, the reduction reaction is preferably performed in an atmosphere of an inert gas such as nitrogen gas or argon gas.

  The reduction product (compound having a silicon-hydrogen bond) generated by the reduction reaction can be isolated from the reaction solution after the reduction reaction by appropriately adopting known isolation means depending on the characteristics and physical properties. For example, when the target reduction product can be extracted with an applicable organic solvent, the target product can be obtained by extraction and distillation of the organic solvent from the extract.

  In a preferred embodiment of the present invention, the silicon-halogen bond of the reaction substrate (compound having a silicon-halogen bond) is converted into a silicon-hydrogen bond by reduction. At this time, when a plurality of silicon-halogen bonds are present in the reaction substrate, all of the silicon-halogen bonds may be reduced, or only some of the silicon-halogen bonds may be reduced. In the reduction reaction in the present invention, a portion other than the halogen atom bonded to the silicon atom may be reduced to hydrogen or the like.

  According to the production method of the present invention as described above, the reduction reaction can be carried out in a uniform reaction system, so that the silicon hydride compound can be produced with high efficiency and high yield. For example, the yield of the silicon compound obtained by the production method of the present invention is usually 80% or more, preferably 83% or more, more preferably 85% or more, and further preferably 90% or more. In the present invention, the yield may be determined by ordinary analysis such as NMR or gas chromatography (GC) analysis.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. Of course, it is possible to implement them, and they are all included in the technical scope of the present invention.

  All reactions in the examples were performed in an inert gas (nitrogen or argon) atmosphere. Further, the solvent used in the reaction in the examples was used after removing water and oxygen.

Moreover, the analysis of the product obtained in each Example was performed by the following method.
<NMR>
The product was dissolved in dehydrated heavy benzene (C ₆ D ₆ ) or deuterated chloroform (CDCl ₃ ). For ¹ H-NMR and ¹³ C-NMR, ²⁹ Si-NMR was used using a Varian nuclear magnetic resonance apparatus. Was measured using a Bruker nuclear magnetic resonance apparatus.
<Gas chromatography (GC)>
The product was diluted in an appropriate solvent, and 0.2 μL of the diluted solution was introduced into a gas chromatograph “GC-2014” manufactured by Shimadzu Corporation and analyzed. FID was used as the detector, “DB-1ms” manufactured by Agilent Technologies was used as the analytical column, and nitrogen gas was used as the carrier gas. The detector temperature is 300 ° C., the column temperature is maintained at 50 ° C. for 5 minutes, then the temperature is increased to 250 ° C. at a temperature increase rate of 20 ° C./min, and then to 300 ° C. at a temperature increase rate of 10 ° C./min. The temperature was raised and the conditions were maintained at 300 ° C. for 10 minutes.

Example 1
In a 100 mL two-necked flask equipped with a thermometer, a condenser, a dropping funnel and a stirrer, 3.0 g (0.012 mol) of diphenyldichlorosilane and 30 mL of toluene were added. The solution in the flask was stirred while maintaining at 0 ° C. or lower, and 7 mL of a toluene solution of bis (2-methoxyethoxy) aluminum sodium hydride (concentration: about 3.6 mol / L) was slowly added dropwise from the dropping funnel. After completion of the dropwise addition, the temperature was gradually raised to room temperature and stirred for 4 hours to carry out a reduction reaction. During this time, the raw materials and products were dissolved in the reaction solution, and the reaction system was uniform. Thereafter, the reaction mixture was hydrolyzed and extracted with cyclopentyl methyl ether, and the extract was concentrated under reduced pressure to obtain a colorless liquid. When the obtained colorless liquid was analyzed by gas chromatography (GC), ¹ H-NMR, ¹³ C-NMR, and ²⁹ Si-NMR, it was confirmed that diphenylsilane was produced. Further, when the reaction yield was calculated by adding an internal standard substance during ¹ H-NMR measurement, the yield of diphenylsilane was 83%.

(Example 2)
In a 100 mL two-necked flask equipped with a thermometer, a condenser, a dropping funnel and a stirrer, 2.00 g (0.007 mol) of chlorotris (trimethylsilyl) silane and 50 mL of toluene were placed. The solution in the flask was stirred while maintaining at 0 ° C. or lower, and 2 mL of a toluene solution of bis (2-methoxyethoxy) aluminum sodium hydride (concentration: about 3.6 mol / L) was slowly added dropwise from the dropping funnel. After completion of the dropwise addition, the temperature was gradually raised to room temperature and stirred for 12 hours to carry out a reduction reaction. During this time, the raw materials and products were dissolved in the reaction solution, and the reaction system was uniform. Thereafter, the reaction mixture was hydrolyzed and extracted with cyclopentyl methyl ether, and the extract was concentrated under reduced pressure to obtain a colorless liquid. When the obtained colorless liquid was analyzed by gas chromatography (GC), ¹ H-NMR, ¹³ C-NMR and ²⁹ Si-NMR, it was confirmed that tris (trimethylsilyl) silane was produced. Further, when the reaction yield was calculated by adding an internal standard substance during ¹ H-NMR measurement, the yield of tris (trimethylsilyl) silane was 80%.

Claims (4)

  A method for producing a silicon compound, comprising reducing a compound having a silicon-halogen bond using an alkali aluminum hydride alkali metal salt.   The method for producing a silicon compound according to claim 1, wherein the reduction is performed in a hydrocarbon solvent.   The method for producing a silicon compound according to claim 1 or 2, wherein the compound having a silicon-halogen bond has a structure in which at least one halogen atom and another silicon atom are bonded to one silicon atom.   The method for producing a silicon compound according to claim 1, wherein the silicon-halogen bond is converted into a silicon-hydrogen bond by the reduction.