JP2020147463A - Method for Producing Cyclic Hydrogenated Silane Compound - Google Patents

Abstract

To provide a method for efficiently producing a cyclic hydrogenated silane compound.SOLUTION: A method for producing a cyclic hydrogenated silane compound comprises a first reaction step of contacting and reacting a salt of a cyclic halosilane compound with a Lewis acid compound in the presence of a solvent to obtain a reaction liquid (A) containing the cyclic halosilane compound, a solid-liquid separation step of removing the salt of the Lewis acid compound contained in the reaction liquid (A) as a solid to obtain a solution containing the cyclic halosilane compound, and a second reaction step of contacting the solution containing the cyclic halosilane compound with a metal hydride to obtain a reaction liquid (B) containing the cyclic hydrogenated silane compound.SELECTED DRAWING: None

Description

The present invention relates to a method for producing a cyclic hydrogenated silane compound.

Thin-film silicon is used for solar cells, semiconductors, and the like, and conventionally, the thin-film silicon is produced by a vapor deposition film forming method (CVD method) using monosilane as a raw material. In recent years, as a simpler method for producing thin film silicon, a method of applying a hydrogenated polysilane solution and firing it has attracted attention. The hydrogenated polysilane is produced from a cyclic hydrogenated silane compound such as cyclopentasilane and cyclohexasilane (Non-Patent Document 1 and the like).

As a method for producing a cyclic hydride silane compound, for example, in Patent Document 1, a salt of a cyclic halosilane compound and a Lewis acid compound are contacted to obtain a cyclic halosilane compound, and the obtained cyclic halosilane compound is contacted with a metal hydride. A method of allowing and reducing the amount is disclosed. More specifically, in Patent Document 1, a white solid containing a phosphonium salt of tetradecachlorocyclohexasilane dianion and aluminum chloride are reacted in benzene with stirring for 4 days, and the obtained reaction solution is used. Benzene was distilled off under reduced pressure to obtain a white solid containing Si ₆ Cl ₁₂ , and this white solid (Si ₆ Cl ₁₂ ) was added to benzene and reduced by adding lithium aluminum hydride to obtain cyclohexasilane. It is described to manufacture.

JP-A-2017-95324

T.Shimoda et al., "Solution-processed silicon films and transistors", Nature, vol.440, p783 (2006)

In Patent Document 1, a white solid containing a phosphonium salt of tetradecachlorocyclohexasilane dianion and aluminum chloride are reacted in benzene, and then benzene is distilled off under reduced pressure because of the low molecular weight together with benzene. This is to remove the silicon compound and increase the purity of the final product, cyclohexasilane. However, if the distillation step is provided, the production efficiency of the target product is lowered. Further, when the reaction product of tetradecachlorocyclohexasilane dianion (Si ₆ Cl ₁₂ ) is reduced with lithium aluminum hydride in a benzene solvent, the melting point of benzene is as high as about 6 ° C., so that the reaction temperature is lowered. Becomes difficult.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method capable of efficiently producing a cyclic hydrogenated silane compound.

The present invention includes the following inventions.
[1] The first reaction step of contacting and reacting a salt of a cyclic halosilane compound with a Lewis acid compound in the presence of a solvent to obtain a reaction solution (A) containing the cyclic halosilane compound.
A solid-liquid separation step of removing a salt of a Lewis acid compound contained as a solid in the reaction solution (A) to obtain a solution containing a cyclic halosilane compound.
The second reaction step of contacting the solution containing the cyclic halosilane compound with a metal hydride to obtain a reaction solution (B) containing the cyclic hydrogenated silane compound.
A method for producing a cyclic hydrogenated silane compound containing.
[2] The method for producing a cyclic hydrogenated silane compound according to [1], wherein the solvent in the first reaction step is at least one of the solvents in the second reaction step.
[3] The method for producing a cyclic hydrogenated silane compound according to [1] or [2], wherein the concentration of the cyclic halosilane compound at the start of the reaction in the second reaction step is 1% by mass or more and 60% by mass or less.
[4] The method for producing a cyclic hydrogenated silane compound according to any one of [1] to [3], wherein the solvent is a hydrocarbon solvent.

According to the present invention, the reaction solution (A) containing the cyclic halosilane compound prepared from the salt of the cyclic halosilane compound is solid-liquid separated, and the solution containing the cyclic halosilane compound is brought into contact with the metal hydride. A silane compound can be efficiently produced.

The production method of the present invention comprises a step of converting a salt of a cyclic halosilane compound into a cyclic halosilane compound (first reaction step), a step of converting a cyclic halosilane compound into a cyclic hydride silane compound (second reaction step), and a first reaction. It has a solid-liquid separation step which is carried out between the step and the second reaction step and removes a salt of a Lewis acid compound contained as a solid in the reaction solution of the first reaction step. That is, the first reaction step, the solid-liquid separation step, and the second reaction step are continuously performed in this order.

I. First Reaction Step The first reaction step is, more specifically, a step of contacting and reacting a salt of a cyclic halosilane compound with a Lewis acid compound in the presence of a solvent to obtain a reaction solution (A) containing the cyclic halosilane compound. Is.

The salt of the cyclic halosilane compound has a structure in which silicon atoms are connected to form a monoprime ring and a halogen atom is bonded to at least one silicon atom constituting the monoprime ring to form a salt. Examples of the compound. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

The number of silicon atoms constituting the monoprime ring is not particularly limited, but 3 or more is preferable, 4 or more is more preferable, 5 or more is further preferable, 8 or less is more preferable, 7 or less is more preferable, and 6 or less is further preferable. preferable.

The cyclic halosilane compound may contain a silicon atom that does not form a monoprime ring. For example, a substituent containing a silicon atom (for example, a silyl group) is bonded to the silicon atom that constitutes the monoprime ring. May be. However, if a silicon atom that does not form a monocyclic ring is contained, in the storage of the cyclic halosilane compound salt or the cyclic halosilane compound, or in the step of reducing the obtained cyclic halosilane compound to produce the cyclic hydride silane compound. Since the amount of silane gas generated tends to increase and the yield of the cyclic hydride silane compound tends to decrease, it is preferable that silicon atoms that do not form a monoelement ring are not contained as much as possible.

It is preferable that at least one halogen atom is bonded to the monoelement ring formed from the silicon atom, and one or two halogen atoms are bonded to each of the silicon atoms constituting the monoelement ring. Is more preferable, and it is further preferable that two halogen atoms are bonded to each of the silicon atoms constituting the monoelement ring.

As the salt of the cyclic halosilane compound, it is preferable to use a salt represented by the following formula (1).

In the above formula (1), X ¹ and X ² each independently represent a halogen atom, L represents an anionic ligand, and p is an integer of -2 to -1 as the valence of the ligand L. Represented, K represents a counter cation, q represents an integer of +1 to +2 as the valence of the counter cation K, n represents an integer of 0 to 5, and a, b, and c are integers of 0 to 2n + 6, respectively. , A + b + c = 2n + 6, a and c are not 0 at the same time, d is an integer of 0 to 3 (however, a and d are not 0 at the same time), and e is an integer of 0 to 3 (however, d + e). = 3), m is 1 to 2, s represents an integer of 1 or more, and t represents an integer of 1 or more.

In the above formula (1), n represents the number of silicon atoms constituting the monoprime ring, and the value thereof is an integer of 0 to 5, preferably 1 or more, more preferably 2 or more, and preferably 4 or less. 3 or less is more preferable. n is particularly preferably 3, that is, the compound represented by the formula (1) is preferably a 6-membered silicon monoprime ring.

In the above formula (1), X ¹ represents a halogen atom bonded to a silicon atom forming a ring, and X ² represents a halogen atom of a silyl group bonded to a silicon atom forming a ring. Examples of the halogen atom of X ¹ and X ² include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, preferably a chlorine atom or a bromine atom, and more preferably a chlorine atom. If the plural X ^1, a plurality of X ¹ may be different even in the same. If the X ² there is a plurality, the plurality of X ² may be different even in the same.

In the above formula (1), a represents the number of halogen atoms bonded to the silicon atoms constituting the ring, b represents the number of hydrogen atoms bonded to the silicon atoms constituting the ring, and c represents the silicon constituting the ring. Represents the number of silyl groups attached to an atom. Further, d represents the number of halogen atoms of the silyl group bonded to the silicon atom constituting the ring, and e represents the number of hydrogen atoms of the silyl group bonded to the silicon atom constituting the ring. When c is 2 or more, the plurality of silyl groups bonded to the silicon atoms forming the ring may be the same or different. a, b and c represent integers of 0 to 2n + 6 (where a + b + c = 2n + 6 and a and c are not 0 at the same time), a is an integer of 1 to 2n + 6 and b and c are integers of 0 to n + 5. It is preferable that a is an integer of n + 6 to 2n + 6, and b and c are integers of 0 to n.

If c is 0 in the above formula (1), side reactions such as a coupling reaction can be suppressed when the compound is reacted with the Lewis acid compound, or a salt of a cyclic halosilane compound or a salt thereof can be produced. The storage stability of the cyclic halosilane compound is improved, the generation of silane gas is suppressed in the step of reducing the obtained cyclic halosilane compound to produce the cyclic hydride silane compound, and the yield of the cyclic hydride silane compound is increased. It is even more preferable in that it can be used. Further, it is particularly preferable that a is 2n + 6 and b and c are 0.

In the above formula (1), L represents an anionic ligand coordinated to a silicon atom constituting the ring, p represents the valence of the ligand L (an integer of -2 to -1), and m. Represents the number of ligands L (1-2). Examples of the anionic ligand include halide ions, nitrate ions, cyanide ions and the like.

In the above formula (1), K represents a counter cation, q represents the valence of the counter cation K (an integer of +1 to +2), and depends on the valence and number of the ligand L and the valence of the counter cation K. The values of s and t are determined respectively. Examples of the countercation K include oniums (for example, phosphonium ion and ammonium ion), polyamine / SiH ₂ Cl ⁺ (for example, pedeta / SiH ₂ Cl ⁺ , teeda / SiH ₂ Cl ^+, etc.) and the like.

When the counter cation K is polyamine / SiH ₂ Cl ⁺ , silane gas, which is a pyrophoric gas, is generated when the compound is reacted with the Lewis acid compound. Therefore, in order to suppress the generation of such silane gas. , The counter cation K is preferably oniums. Further, when the countercation K is onium, it is preferable from the viewpoint that the yield of the cyclic halosilane compound is improved when the cyclic halosilane compound is produced by contacting with the salt of the cyclic halosilane compound.

As the oniums of the counter cation K, a phosphonium ion represented by the following formula (2) or an ammonium ion represented by the following formula (3) is preferable.

R ^{1 to} R ⁴ in the above formula (2) and R ^{5 to} R ⁸ in the above formula (3) independently represent a hydrogen atom, an alkyl group, and an aryl group, respectively.

In the above formula (2), R ^{1 to} R ⁴ may be different from each other, but it is preferable that they are all the same group. In the above formula (3), R ^{5 to} R ⁸ may be different from each other, but it is preferable that they are all the same group. The alkyl groups of R ^{1 to} R ⁴ and R ^{5 to} R ⁸ include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, cyclohexyl group and the like. Alkyl groups having 1 to 16 carbon atoms are preferably mentioned, and alkyl groups having 1 to 8 carbon atoms are more preferable. As the aryl group of R ^{1 to} R ⁴ and R ^{5 to} R ⁸ , preferably an aryl group having 6 to 18 carbon atoms such as a phenyl group and a naphthyl group is preferable, and an aryl group having 6 to 12 carbon atoms is more preferable. ..

Specific examples of the salt of the cyclic halosilane compound represented by the above formula (1) include a salt of a tetradecachlorocyclohexasilane dianion complex ([Si ₆ Cl ₁₄ ^2- ]) and a tetradecabromocyclohexaci. Examples thereof include salts of orchid dianion complex ([Si ₆ Br ₁₄ ^2- ]). Further, as the counter ion, a phosphonium ion or an ammonium ion is preferable.

As the salt of the cyclic halosilane compound represented by the above formula (1), it is preferable to use a compound represented by the following formula (4) or the following formula (5). When such a compound is used as the salt of the cyclic halosilane compound, the formation of by-products and the formation of silane gas, which is a pyrophoric gas, can be suppressed when the salt of the cyclic halosilane compound is reacted with the Lewis acid compound. The compound can be easily produced. Further, the obtained cyclic halosilane compound can be reduced to efficiently produce a cyclic hydrogenated silane compound.

In the above formula (4) and the above formula (5), X ¹ , R ^{1 to} R ⁴ , R ^{5 to} R ⁸ , n and a have the same meanings as described above, and X ³ represents a halogen atom. In addition, X ³ exists in the form of an ion in the above formula (4) and the above formula (5), and is a halide ion.

Examples of the halogen atom of X ³ include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, preferably a chlorine atom or a bromine atom, and more preferably a chlorine atom. If the X ³ have more than one plurality of X ³ may be different even in the same. The above X ¹ and the above X ³ may be the same or different. In the above formula (4) and the above formula (5), if X ¹ and X ³ are all chlorine atoms, a cyclic hydrogenated silane compound can be produced at low cost.

In the above formula (4) and the above formula (5), n represents an integer of 0 to 5, a represents an integer of 1 to 2n + 6, and n is particularly preferably 3, in which case a is 6 The above is preferable, 9 or more is more preferable, and 12 is particularly preferable.

The salt of the cyclic halosilane compound may be purified, if necessary, prior to the reaction with the Lewis acid compound. By purifying the salt of the cyclic halosilane compound to increase its purity, the formation of by-products can be suppressed by the reaction with the Lewis acid compound. The salt of the cyclic halosilane compound may be purified by a known purification method such as solid-liquid separation, distillation (solvent distilling), crystallization, and extraction.

In the first reaction step, the salt of the cyclic halosilane compound is reacted with the Lewis acid compound. The type of the Lewis acid compound is not particularly limited, but it is preferable to use a metal halide.

Examples of the metal elements constituting the metal halide include Group 4 elements such as titanium and zirconium, Group 11 elements such as copper, silver and gold, Group 13 elements such as boron, aluminum, gallium, indium and tarium, and calcium. , Iron, zinc and the like. Among these, Group 13 element is preferable, and aluminum is more preferable.
Examples of the metal halide include metal fluoride, metal chloride, metal bromide, and metal iodide, but it is preferable to use metal chloride from the viewpoint of reactivity and ease of control of the reaction.

Specific examples of the Lewis acid compound include titanium halides such as titanium chloride and titanium bromide; zirconium halides such as zirconium chloride and zirconium bromide; copper halides such as copper chloride and copper bromide; silver chloride. , Silver halides such as silver bromide; Gold halides such as gold chloride and gold bromide; Boron halides such as boron trifluoride, boron trichloride, boron tribromide; Halogenates such as aluminum chloride and aluminum bromide Aluminum bromide; gallium halide such as gallium chloride and gallium bromide; indium halide such as indium chloride and indium bromide; talium halide such as tallium chloride and talium bromide; calcium halide such as calcium chloride and calcium bromide ; Iron halide such as iron chloride and iron bromide; zinc halide such as zinc chloride and zinc bromide; and the like.

The amount of the Lewis acid compound used may be appropriately adjusted according to the reactivity between the salt of the cyclic halosilane compound and the Lewis acid compound. For example, 0.5 mol or more is preferable with respect to 1 mol of the salt of the cyclic halosilane compound. 1.5 mol or more is more preferable, 20 mol or less is preferable, and 10 mol or less is more preferable.

The solvent used in the first reaction step is preferably an organic solvent, and examples thereof include a hydrocarbon solvent; an ether solvent such as diethyl ether, tetrahydrofuran, cyclopentyl methyl ether, diisopropyl ether, and methyl tertiary butyl ether; and the like. , A hydrocarbon solvent is preferable. Examples of the hydrocarbon-based solvent include aliphatic hydrocarbon-based solvents such as hexane, heptane, octane, nonane, and decane; aromatic hydrocarbon-based solvents such as benzene, toluene, and xylene; and aliphatic hydrocarbons. System solvents, toluene, xylene and the like are more preferable, and aliphatic hydrocarbon-based solvents are particularly preferable. As will be described later, the solvent in the first reaction step is preferably at least one of the solvents in the second reaction step, and when the solvent in the second reaction step is an aliphatic hydrocarbon solvent, the reaction system is made more efficient. Can be cooled well. Further, in the present invention, after the first reaction step, a solid-liquid separation step (filtration step or the like) for removing the salt of the Lewis acid compound contained as a solid is performed. If an aliphatic hydrocarbon-based solvent is used in the first reaction step, In the solid-liquid separation step, the removal selectivity of the by-product (salt of the Lewis acid compound) in the first reaction step can be enhanced, and the reaction residue generated from the metal hydrocarbon used in the second reaction step. (Metal salt) can be easily separated.

The reaction solvent is preferably purified in advance by distillation, dehydration, or the like in order to remove water and dissolved oxygen contained therein.

The amount of the reaction solvent used is not particularly limited, but it is usually preferable to adjust the concentration of the salt of the cyclic halosilane compound to be 0.005 mol / L or more and 10 mol / L or less, and a more preferable concentration is 0.01 mol. / L or more, a more preferable concentration is 0.10 mol / L or more, a more preferable concentration is 5 mol / L or less, and a further preferable concentration is 1 mol / L or less.

The method for contacting the salt of the cyclic halosilane compound with the Lewis acid compound in the above reaction solvent is not particularly limited. For example, (1) the salt of the cyclic halosilane compound and the Lewis acid compound are each dissolved or dispersed in the solvent in advance. A method of preparing a solution (or dispersion) of a salt of a cyclic halosilane compound and a solution (or dispersion) of a Lewis acid compound, and then mixing these solutions (or dispersion), (2) in a solvent. A method of adding a salt of a cyclic halosilane compound and a Lewis acid compound simultaneously or sequentially, (3) a method of adding a Lewis acid compound to a solution (or dispersion) of a salt of a cyclic halosilane compound, (4) a method of adding a salt of a cyclic halosilane compound and Lewis acid. Examples thereof include a method in which a compound is charged and a solvent is added thereto.

The temperature at which the salt of the cyclic halosilane compound and the Lewis acid compound are brought into contact with each other to carry out the reaction may be appropriately adjusted according to the reactivity, but for example, -80 ° C or higher is preferable, and -50 ° C or higher is preferable. More preferably, it is more preferably −30 ° C. or higher, further preferably 200 ° C. or lower, further preferably 150 ° C. or lower, still more preferably 100 ° C. or lower.

The time for contacting the salt of the cyclic halosilane compound with the Lewis acid compound may be appropriately set according to the reaction temperature and the degree of progress of the reaction. For example, 1 hour or more is preferable, and 2 hours or more is preferable. Is more preferable, and 3 hours or more is further preferable. The reaction time is preferably 48 hours or less, more preferably 24 hours or less, and even more preferably 15 hours or less.

Heating and / or stirring may be carried out in order to accelerate the reaction between the salt of the cyclic halosilane compound and the Lewis acid compound.

The atmosphere when the salt of the cyclic halosilane compound and the Lewis acid compound are brought into contact with each other to carry out the reaction is not particularly limited, but in order to suppress the oxidation of the cyclic halosilane compound and its salt, the oxygen concentration in the atmosphere is 9 volumes. % Or less is preferable, 5% by volume or less is more preferable, 3% by volume or less is further preferable, and 1% by volume or less is particularly preferable.

Further, in order to suppress the hydrolysis of the cyclic halosilane compound and its salt, the water concentration in the above atmosphere is preferably 2000 ppm (volume basis) or less, more preferably 1500 ppm (volume basis) or less, and further preferably 1000 ppm (volume basis) or less. , 500 ppm (volume basis) or less is even more preferable, 150 ppm (volume basis) or less is particularly preferable, and 10 ppm (volume basis) or less is most preferable.

The reaction between the salt of the cyclic halosilane compound and the Lewis acid compound is preferably carried out in an atmosphere of an inert gas (for example, nitrogen gas or argon gas), and is also preferably carried out in a light-shielded state.

In the first reaction step, for example, the cyclic halosilane compound represented by the following formula (6) can be obtained from the salt of the cyclic halosilane compound represented by the above formula (1).

In the above formula (6), X ¹ , X ² , a to e, and n have the same meanings as described above.

II. Solid-liquid separation step In the reaction solution (A) containing the cyclic halosilane compound prepared as described above, the target cyclic halosilane compound is dissolved, while the salt of the Lewis acid compound, which is a by-product, is solid. It is precipitated as. Therefore, the solid (salt of the Lewis acid compound) is removed by the solid-liquid separation step, and the liquid (the liquid in which the cyclic halosilane compound is dissolved) is recovered. Examples of this solid-liquid separation step include filtration, precipitation separation, centrifugation, decantation, and the like, and filtration is preferable. According to filtration, solid-liquid separation can be performed easily and accurately.

In the solid-liquid separation step, the separated solid may be washed with an appropriate solvent, and the washing liquid may be mixed with the filtrate. By adding the cleaning liquid, the recovery rate of the cyclic halosilane compound can be increased. The solvent used in the washing liquid can be selected from the same range as the reaction solvent exemplified in the first reaction step, and may be the same as the reaction solvent used in the first reaction step. A preferred cleaning solvent is an aliphatic hydrocarbon solvent.

In the first reaction step, as long as the dissolved state of the cyclic halosilane can be maintained after the preparation of the reaction solution (A) containing the cyclic halosilane compound and before the solid-liquid separation step and / or after the separation step. A step of distilling off the used reaction solvent (for example, a concentration step) may be performed. Further, the same solvent as the solvent to be distilled off or a different solvent may be added at at least one step selected before, during the distillation, and after the distillation of the reaction solvent used in the first reaction step. The step of combining the distillation and addition of distillate is referred to as a concentration adjusting step or a solvent replacement step. Even when the concentration step, the concentration adjustment step, the solvent replacement step and the like are performed, it is preferable that the solution containing the cyclic halosilane compound to be prepared contains the solvent used in the first reaction step.

III. Second reaction step In the second reaction step, the solution containing the cyclic halosilane compound obtained in the first reaction step and the solid-liquid separation step is brought into contact with the metal hydride to prepare the reaction solution (B) containing the cyclic hydrogenated silane compound. This is the process of obtaining.

Examples of the metal hydride include aluminum hydride compounds such as lithium aluminum hydride, diisobutylaluminum hydride, and sodium bis (2-methoxyethoxy) borohydride; sodium borohydride, lithium triethylborohydride, and boron borohydride. Examples thereof include boron borohydride compounds such as nickel and zinc borohydride; tin hydride compounds such as tributyltin hydride; and transition metal compounds hydride. Only one kind of these metal hydrides may be used, or two or more kinds may be used in combination.

The amount of the metal hydride used may be appropriately set. For example, the equivalent of hydride of the metal hydride with respect to one silicon-halogen bond of the cyclic halosilane compound is preferably 0.5 equivalent or more, preferably 0.8. Equivalent or more is more preferable, 0.9 equivalent or more is further preferable, 15 equivalent or less is preferable, 5 equivalent or less is more preferable, and 2 equivalent or less is further preferable. If the amount of the metal hydride used is too small, the yield tends to decrease, which is not preferable. On the other hand, if the amount of the metal hydride used is too large, it takes time for post-treatment and the productivity tends to decrease, which is not preferable.

In the second reaction step, it is preferable to use the solvent contained in the solution containing the cyclic halosilane compound as it is as the reaction solvent, but if necessary, a solvent other than the solvent used in the first reaction step as the solvent in the second reaction step. May include. The solvent other than the solvent used in the first reaction step may be added after the start of the second reaction step, or may be a solvent for dissolving or dispersing the metal hydride. The solvent used in the second reaction step can be appropriately selected from those exemplified as the solvent in the first reaction step.

The amount of the solvent common to the first reaction step is, for example, 30% by mass or more, preferably 50% by mass or more, and more preferably 80% by mass or more, based on 100% by mass of the total solvent used in the second reaction step. , 100% by mass.

As the solvent in the second reaction step, saturated aliphatic hydrocarbons are particularly preferable, and the amount of saturated aliphatic hydrocarbons is, for example, 30% by mass or more in 100% by mass of the total solvent at the end of the reaction in the second reaction step. It is preferably 40% by mass or more, more preferably 50% by mass or more. The larger the amount of saturated aliphatic hydrocarbon in the second reaction step, the easier it is to remove by-products (metal salts that are the reaction residue of the metal hydride) in the second reaction step by solid-liquid separation. preferable.

The concentration of the cyclic halosilane compound at the start of the reaction (that is, the concentration of the cyclic halosilane compound in the solution containing the cyclic halosilane compound) can be set within a range in which the cyclic halosilane compound dissolves, and is, for example, 1% by mass or more, preferably 3% by mass. % Or more, more preferably 5% by mass or more, for example, 80% by mass or less, preferably 70% by mass or less, more preferably 50% by mass or less.

The method of contacting the solution containing the cyclic halosilane compound with the metal hydride is not particularly limited, and for example, (1) a method of adding one of the solution of the cyclic halosilane compound and the metal hydride to the other, and (2) the cyclic halosilane compound. A method of preparing a solution and a solution or dispersion containing a metal hydride and a solvent and mixing the two in an appropriate procedure; and the like are mentioned, and the aspect (2) above is preferable.

As the aspect of (2) above, (A) a solution of a cyclic halosilane compound is charged in a reaction vessel, and a solution of a metal hydride or a dispersion is added thereto, and (B) metal hydrogen in a reactor. A mode in which a solution or dispersion of a compound is charged and a solution of a cyclic halosilane compound is added thereto. (C) A solution of the cyclic halosilane compound and a metal hydride are placed in a reactor in which a solvent is charged if necessary. Examples thereof include a mode in which the solution or dispersion of the above is added simultaneously or sequentially.

When the solution of the cyclic halosilane compound and the solution or dispersion of the metal hydride are mixed, the concentration of the metal hydride is, for example, 0.1 mol / L or more, preferably 0.3 mol / L or more, more preferably 0. It is .5 mol / L or more, for example, 20 mol / L or less, preferably 10 mol / L or less, and more preferably 5 mol / L or less.

The reaction temperature in the second reaction step is, for example, preferably −50 ° C. or higher, more preferably −30 ° C. or higher, further preferably −20 ° C. or higher, further preferably 80 ° C. or lower, more preferably 70 ° C. or lower, and more preferably 60 ° C. The following is more preferable, and 50 ° C. or lower is particularly preferable. The reaction time of the second reaction step may be appropriately adjusted according to the degree of progress of the reaction. For example, 10 minutes or more is preferable, 1 hour or more is more preferable, 2 hours or more is further preferable, and 72 hours or less is preferable. It is preferably 48 hours or less, more preferably 24 hours or less.

The cyclic hydride silane compound is an oxygen-free substance. Therefore, the second reaction step is preferably carried out in an atmosphere of an inert gas such as nitrogen gas or argon gas.

The cyclic hydrogenated silane compound obtained in the second reaction step may be purified in order to increase the purity. As a method for purifying the cyclic hydrogenated silane compound, known purification methods such as solid-liquid separation, distillation, crystallization, and extraction can be adopted. For example, solid-liquid separation can be performed to easily remove the metal salt which is the reaction residue of the metal hydride.

Further, by performing distillation, light boiling impurities having a lower boiling point than the cyclic hydride silane compound and high boiling impurities having a higher boiling point than the cyclic hydride silane compound can be removed. In the present invention, after obtaining the reaction solution (A) in which the cyclic halosilane compound is dissolved in the first reaction step, the cyclic halosilane compound is used in the second reaction step without being concentrated and solidified. Therefore, the reaction solution (A) It contains low boiling point impurities (such as low molecular weight silicon compounds) that dissolve in the second reaction step, and these low boiling point impurities can be removed by distillation after the second reaction step.

Examples of the distillation include short-stroke distillation, thin-film distillation, precision distillation such as molecular distillation, and distillation in a distillation column, and these distillations may be appropriately combined. In particular, it is preferable to perform the precision distillation and then distill in a distillation column.

The pressure in precision distillation is, for example, preferably performed at a decompression degree (absolute pressure) of 3 kPa or less, more preferably 1 kPa or less, still more preferably 500 Pa or less, and particularly preferably 200 Pa or less (absolute pressure). .. The lower limit of the degree of decompression (absolute pressure) in precision distillation is not particularly limited, but in actual operation, 1 Pa or more is preferable, and 10 Pa or more is more preferable. The distillation temperature in precision distillation is, for example, 25 to 80 ° C, preferably 30 to 70 ° C, and more preferably 35 to 65 ° C.

Distillation in the distillation column is preferably performed at a decompression degree (absolute pressure) of 5 kPa or less, more preferably 2 kPa or less, still more preferably 1 kPa or less, and particularly preferably 200 Pa or less. The lower limit of the degree of decompression (absolute pressure) is not particularly limited, but in actual operation, 5 Pa or more is preferable, and 10 Pa or more is more preferable. The temperature of distillation in the distillation column is, for example, 30 to 100 ° C., preferably 35 to 90 ° C., and more preferably 40 to 85 ° C. It is preferable to set the temperature higher than the temperature used in precision distillation.

The cyclic hydride silane compound obtained in the second reaction step is a compound having a monoprime ring composed of a series of silicon atoms and composed of a silicon atom and a hydrogen atom. The cyclic hydrogenated silane compound may have a hydrogen atom bonded to all the substitution positions of the silicon atom constituting the monoelement ring, and an unsubstituted silyl group is bonded to the silicon atom constituting the monoelement ring. It may be. However, from the viewpoint of storage stability, it is preferable that the silicon atom other than the silicon atom constituting the monoprime ring is not contained. By reducing the cyclic halosilane compound instead of the salt of the cyclic halosilane compound, the generation of silane gas derived from the countercation of the salt is not generated, and the generation of silane gas can be suppressed as a whole. Therefore, the cyclic hydrogenated silane compound can be produced in high yield. It can be easily obtained.

The cyclic hydrogenated silane compound is preferably a compound represented by the following formula (7).
Si _z H _2z (7)

In the above formula (7), z represents the number of silicon atoms constituting the monoprime ring, and z is preferably 3 or more, more preferably 4 or more, further preferably 5 or more, still preferably 8 or less, and preferably 7 or less. More preferably, 6 or less is further preferable.
The number of silicon atoms constituting the monoprime ring is particularly preferably 6 (that is, z = 6) from the viewpoint of being useful for forming thin film silicon. From the same viewpoint, the cyclic halosilane compound to be used in the second reaction step is preferably a compound represented by the following formula (8), and more preferably a compound represented by the following formula (9).
Si _z X ¹ _a H _(2z-a) (8)
Si _z X ¹ _2z (9)

In the above formula (8) and the above formula (9), the modes of X ¹ and a and the preferred modes are the same as those of X ¹ and a in the above formula (1), respectively, unless otherwise specified, and the mode of z. And a preferred embodiment have the same meaning as z in the above formula (7), unless otherwise specified.

IV. Step for Producing Salt of Cyclic Halosilane Compound In addition, a known method can be appropriately adopted as a method for producing a salt of the cyclic halosilane compound which is a raw material of the first reaction step of the present invention. For example, a halosilane compound and a tertiary polyamine are used. It can be produced by contacting or by contacting the halosilane compound with at least one of the phosphonium salt and the ammonium salt, and preferably by contacting the halosilane compound with at least one of the phosphonium salt and the ammonium salt. When the halosilane compound is brought into contact with at least one of the phosphonium salt and the ammonium salt, a cyclization coupling reaction of the halosilane compound occurs, and the cyclic halosilane compound containing a ring formed by connecting the silicon atoms of the halosilane compound and the phosphonium ion. Alternatively, a salt with ammonium ion can be obtained (hereinafter, may be referred to as a cyclization coupling step).

As the halosilane compound, a halogenated disilane such as hexachlorodisilane, hexabromodisilane, or hexaiododisilane, or a halogenated monosilane compound can be used, and it is preferable to use a halogenated monosilane compound. When the halogenated monosilane compound is used, a salt of a cyclic halosilane compound containing no silicon atom other than the silicon atom forming the ring structure can be produced, and the generation of silane gas during storage or post-reaction can be suppressed.

Examples of the halogenated monosilane compound include trihalogenated silanes such as trichlorosilane, tribromosilane, triiodosilane and trifluorosilane; dihalogenated silanes such as dichlorosilane, dibromosilane, diiodosilane and difluorosilane; tetrachlorosilane, Tetrahalogenated silanes such as tetrabromosilane, tetraiodosilane, and tetrafluorosilane; and the like are mentioned, and among these, trihalogenated silane is preferable, and trichlorosilane is more preferable.

The phosphonium salt is preferably a quaternary phosphonium salt, and a salt represented by the following formula (10) is preferably mentioned. Further, the ammonium salt is preferably a quaternary ammonium salt, and a salt represented by the following formula (11) is preferably mentioned.

The embodiments and preferred embodiments of R ^{1 to} R ⁴ in the above formula (10) and R ^{5 to} R ⁸ in the above formula (11) are the same as those in the above formula (2) and the above formula (3) unless otherwise specified. have the meanings, a ^- represents a monovalent anion.

In the above formula (10) and the formula (11), A ^- Examples of the monovalent anion represented by the halide ion ^{(e.g., Cl -, Br -, I} - , etc.), borate ions (e.g., BF ₄ ^- ), phosphorus-based anions (e.g., PF ₆ ^-) and the like. Among these, Cl ⁻ , Br ⁻ , and I ⁻ are preferable, and Cl ⁻ or Br ⁻ is particularly preferable from the viewpoint of easy availability.

In the cyclization coupling step, only one of the phosphonium salt and the ammonium salt may be used, or both may be used. As the phosphonium salt, only one kind may be used, or two or more kinds may be used in combination. As the ammonium salt, only one kind may be used, or two or more kinds may be used in combination.

In the above formula (10), R ^{1 to} R ⁴ may be different from each other, but it is preferable that they are all the same group. In the above formula (11), R ^{5 to} R ⁸ may be different from each other, but it is preferable that they are all the same group.

By using the phosphonium salt represented by the above formula (10) or the ammonium salt represented by the above formula (11), a salt of the cyclic halosilane compound represented by the above formula (4) or the above formula (5) can be obtained. In particular, a salt of a cyclic halosilane compound containing a 6-membered silicon monoelement ring and containing no silicon atom other than the silicon atom forming the monoelement ring can be easily obtained.

For example, when trichlorosilane is used as the halosilane compound and a compound in which A ⁻ in the above formula (10) is a chlorine ion (Cl ⁻ ) and R ^{1 to} R ⁴ are phenyl groups is used as the phosphonium salt, Dodecachlorodihydrocyclohexasilane dianion salt (eg, [Ph ₄ P ⁺ ] ₂ [Si ₆ H ₂ Cl ₁₂ ] ^2- ), tridecachlorohydrocyclohexasilane dianion salt (eg, [Ph ₄ P ⁺ ]] Dianions and phosphonium ions of cyclic halosilane compounds such as ₂ [Si ₆ HCl ₁₃ ] ^2- ), tetradecachlorocyclohexasilane dianion salts (eg [Ph ₄ P ⁺ ] ₂ [Si ₆ Cl ₁₄ ] ^2- ) A salt consisting of is obtained.

Further, using trichlorosilane as a halosilane compound, A in the formula (11) in the ammonium salt ^- bromine ion (Br ^-) is, in the case of using a compound R ⁵ to R ⁸ is an ethyl group, Dodecachlorodihydrocyclohexasilane dianion salt (eg, [Et ₄ N ⁺ ] ₂ [Si ₆ H ₂ Cl ₁₂ ] ^2- ), tridecachlorohydrocyclohexasilane dianion salt (eg, [Et ₄ N ⁺ ]] Dianions and ammonium ions of cyclic halosilane compounds such as ₂ [Si ₆ HCl ₁₃ ] ^2- ), tetradecachlorocyclohexasilane dianion salt (eg [Et ₄ N ⁺ ] ₂ [Si ₆ Cl ₁₄ ] ^2- ) A salt consisting of is obtained.

The amount of the phosphonium salt and / or ammonium salt used (the total amount used when two or more kinds are used) is preferably 0.01 mol or more, more preferably 0.05 mol or more, and 0. 08 mol or more is further preferable, 1.0 mol or less is more preferable, 0.7 mol or less is more preferable, and 0.5 mol or less is further preferable. If the amount of the phosphonium salt and / or the ammonium salt used is too small, the halosilane compound may not react and the yield of the salt of the cyclic halosilane compound may decrease. On the other hand, if the amount of the phosphonium salt and / or the ammonium salt used is too large, the purity of the salt of the cyclic halosilane compound may decrease.

The cyclization coupling step may be carried out in the presence of a chelated ligand. By carrying out the cyclization coupling reaction in the presence of a chelate-type ligand, a salt of the cyclic halosilane compound can be efficiently produced. In addition, the number of hydrogens and the composition ratio in the obtained cyclic halosilane compound can be adjusted by appropriately selecting the type of chelate-type ligand to be used. As the chelate-type ligand, for example, a polyether compound, a polythioether compound, a polydentate phosphine compound and the like can be used.

Examples of the polyether compound include 1,1-dimethoxyethane, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,2-dipropoxyethane, 1,2-diisopropoxyethane, 1, 2-Dibutoxyethane, 1,2-Diphenoxyethane, 1,3-dimethoxypropane, 1,3-diethoxypropane, 1,3-dipropoxypropane, 1,3-diisopropoxypropane, 1,3- Dibutoxypropane, 1,3-diphenoxypropane, 1,4-dimethoxybutane, 1,4-diethoxybutane, 1,4-dipropoxybutane, 1,4-diisopropoxybutane, 1,4-dibutoxy Examples thereof include dialkoxyalcans such as butane and 1,4-diphenoxybutane. Among these, 1,2-dimethoxyethane is particularly preferable.

Examples of the polythioether compound include those in which the oxygen atom of the above-exemplified polyether compound is replaced with a sulfur atom.

Examples of the polydentate phosphine compound include 1,2-bis (dimethylphosphino) ethane, 1,2-bis (diethylphosphino) ethane, 1,2-bis (dipropylphosphino) ethane, 1,2. -Bis (dibutylphosphino) ethane, 1,2-bis (diphenylphosphino) ethane, 1,3-bis (dimethylphosphino) propane, 1,3-bis (diethylphosphino) propane, 1,3-bis (Dipropylphosphino) propane, 1,3-bis (dibutylphosphino) propane, 1,3-bis (diphenylphosphino) propane, 1,4-bis (dimethylphosphino) butane, 1,4-bis ( Bis (dialkylphosphino) such as diethylphosphino) butane, 1,4-bis (dipropylphosphino) butane, 1,4-bis (dibutylphosphino) butane, 1,4-bis (diphenylphosphino) butane, etc. Examples include alkanes and bis (diarylphosphino) alkanes. Among these, 1,2-bis (diphenylphosphino) ethane is particularly preferable.

The amount of the chelate-type ligand used may be appropriately set. For example, 0.01 mol or more is preferable, 0.05 mol or more is more preferable, 0.1 mol or more is more preferable, and 50 mol or more is preferable with respect to 1 mol of the halosilane compound. The following is preferable, 40 mol or less is more preferable, and 30 mol or less is further preferable.

The cyclization coupling step is preferably carried out in the presence of a basic compound. Examples of the basic compound include (mono-, di-, tri-, poly-) amine compounds, and among them, monoamine compounds are preferably used. Specifically, for example, triethylamine, tripropylamine, tributylamine, trioctylamine, triisobutylamine, triisopentylamine, diethylmethylamine, diisopropylethylamine, dimethylbutylamine, dimethyl-2-ethylhexylamine, diisopropyl-2- Ethylhexylamine, methyldioctylamine and the like are preferable, and tributylamine is particularly preferable. As the basic compound, only one kind may be used, or two or more kinds may be used in combination.

The amount of the basic compound used (when two or more types are used, the total amount used) may be appropriately set according to the type and the like. For example, in the case of a monoamine compound, 1 mol of the halosilane compound is used. 0.1 mol or more is preferable, 0.2 mol or more is more preferable, 0.4 mol or more is further preferable, 2 mol or less is preferable, 1.8 mol or less is more preferable, and 1.5 mol or less is further preferable. If the amount of the basic compound (monoamine compound) is too small, the halosilane compound may not react and the yield of the salt of the cyclic halosilane compound may decrease. On the other hand, if the amount of the basic compound (monoamine compound) is too large, the yield or purity of the salt of the cyclic halosilane compound may decrease.

Diamine compounds, triamine compounds, and polyamine compounds can also be used as the basic compounds, but in that case, the amount (total amount) of these basic compounds (di-, tri-, poly-amine) used is determined. In order to suppress the by-production of impurities derived from polyamines, the amount is preferably 0.5 mol or less, more preferably 0.4 mol or less, still more preferably 0.3 mol or less, based on 1 mol of the halosilane compound.

The cyclization coupling step is preferably carried out in a solvent. As the solvent used here (hereinafter, may be referred to as a reaction solvent), an organic solvent is preferable. As the organic solvent, a solvent that does not interfere with the cyclization coupling reaction is preferable, and for example, a halogenated hydrocarbon solvent such as chloroform, dichloromethane, 1,2-dichloroethane; diethyl ether, tetrahydrofuran, cyclopentyl methyl ether, diisopropyl ether, etc. Ether-based solvents such as methyl tertiary butyl ether; aprotonic polar solvents such as acetonitrile and N, N-dimethylformamide; and the like are preferably used. Among these, halogenated hydrocarbon solvents are more preferable, chlorinated hydrocarbon solvents such as chloroform, dichloromethane and 1,2-dichloroethane are preferably used, and dichloromethane is particularly preferable.

The amount of the solvent used in the cyclization coupling step is not particularly limited, but it is usually preferable to adjust the concentration of the halosilane compound to be 0.5 mol / L or more and 10 mol / L or less, and the more preferable concentration is 0.8 mol / L or more, a more preferable concentration is 1 mol / L or more, a more preferable concentration is 8 mol / L or less, and a further preferable concentration is 5 mol / L or less.

The reaction temperature of the cyclization coupling step may be appropriately adjusted according to the reactivity, and is, for example, about 0 to 120 ° C, preferably about 15 to 70 ° C. Here, the reaction temperature means the liquid temperature in the reactor.

The reaction time of the cyclization coupling reaction may be appropriately set according to the reaction temperature and the degree of progress of the reaction. For example, 1 hour or more is preferable, 2 hours or more is more preferable, and 3 hours or more is further preferable. Further, 48 hours or less is preferable, 24 hours or less is more preferable, and 12 hours or less is particularly preferable. Further, during the reaction, stirring may be performed at the same time as heating in order to accelerate the reaction.

The cyclization coupling reaction is preferably carried out under substantially anhydrous conditions, and is preferably carried out in a dry gas (particularly an inert gas such as nitrogen gas or argon gas) atmosphere.

The salt of the cyclic halosilane compound which is the raw material of the first reaction step may be appropriately purified by known means such as solid-liquid separation, distillation, crystallization and extraction. The solid-liquid separation means at this time is not particularly limited, and known solid-liquid separation means such as filtration, precipitation separation, centrifugation, and decantation can be used.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by the following Examples, and the present invention shall be carried out with modifications to the extent that it can be adapted to the above and the purposes described below. Of course, they are also possible, and they are all included in the technical scope of the present invention.

(1) Preparation of Salt of Cyclic Halosilane Compound After replacing the inside of a 2L four-necked flask equipped with a thermometer, a condenser, a dropping funnel and a stirrer with nitrogen gas, 123.5 g (0) of tetraethylammonium bromide was placed in this flask. .59 mol), 490.0 g (2.64 mol) of tributylamine, and 702.7 g of dichloromethane were added. Then, while stirring the solution in the flask, a solution consisting of 238.1 g (1.76 mol) of trichlorosilane and 117.2 g of dichloromethane was slowly added dropwise from the dropping funnel under 25 ° C. conditions. After completion of the dropping, the mixture was stirred as it was for 2 hours, followed by stirring at 50 ° C. for 6 hours while heating and refluxing to carry out a cyclization coupling reaction. After the reaction, the obtained solid was filtered and purified to obtain a white solid containing 102.7 g of a salt of a cyclic halosilane compound ([Et ₄ N] ₂ [Si ₆ Cl ₁₄ ]) (molecular weight 925) (yield). 38%).

(2) Preparation of Solution Containing Cyclic Halosilane Compound Under a nitrogen atmosphere, 15.0 g of the cyclic halosilane compound salt obtained in (1) above and powdered aluminum chloride (aluminum chloride) were placed in a 300 mL three-necked flask equipped with a stirrer. 4.6 g (particle size 2.0 mm or less) of AlCl ₃ ) was added, and 98.7 g of normal hexane was further added. After reacting under 24 ° C. conditions for 3 hours in a nitrogen atmosphere and in a light-shielded state, filtration was performed, and 115.7 g (concentration: 4.) of a solution containing a cyclic halosilane compound (Si ₆ Cl ₁₂ ) (molecular weight 594). 8% by mass) was obtained (yield 58%). The yield was calculated from the mass of a part of the obtained solution concentrated.

(3) Preparation of Cyclic Hydrogenated Silane Compound 100.0 g of the cyclic halosilane compound-containing solution obtained in (2) above was placed in a 100 mL three-necked flask equipped with a dropping funnel and a stirrer. After replacing the inside of the flask with nitrogen gas, while stirring the solution in the flask, under 0 ° C. conditions, 38 mL of a diethyl ether solution of lithium aluminum hydride (concentration: about 1.0 mol / L) as a reducing agent from the dropping funnel. Was gradually added dropwise, and then the reduction reaction was carried out by stirring at 20 ° C. for 3 hours. After the reaction, the obtained reaction solution was filtered under a nitrogen atmosphere to remove the produced salt, and the obtained filtrate was analyzed by gas chromatography (GC). As a result, cyclohexasilane (Si ₆ H ₁₂ ) was found. It was confirmed that it was produced (yield 90%). Further, the obtained filtrate was concentrated under reduced pressure and then purified by distillation to obtain high-purity cyclohexasilane as a colorless and transparent liquid.

According to the present invention, a cyclic silane hydride compound can be produced. The cyclic hydride silane compound is useful as a silicon raw material used in, for example, solar cells and semiconductors. Further, in the semiconductor field, it can be used for producing a SiGe compound or a SiGe film by mixing or reacting with a Ge compound.

Claims (4)

The first reaction step of contacting and reacting a salt of a cyclic halosilane compound with a Lewis acid compound in the presence of a solvent to obtain a reaction solution (A) containing the cyclic halosilane compound.
A solid-liquid separation step of removing a salt of a Lewis acid compound contained as a solid in the reaction solution (A) to obtain a solution containing a cyclic halosilane compound.
The second reaction step of contacting the solution containing the cyclic halosilane compound with a metal hydride to obtain a reaction solution (B) containing the cyclic hydrogenated silane compound.
A method for producing a cyclic hydrogenated silane compound containing. The method for producing a cyclic hydrogenated silane compound according to claim 1, wherein the solvent in the first reaction step is at least one of the solvents in the second reaction step. The method for producing a cyclic hydrogenated silane compound according to claim 1 or 2, wherein the concentration of the cyclic halosilane compound at the start of the reaction in the second reaction step is 1% by mass or more and 60% by mass or less. The method for producing a cyclic hydrogenated silane compound according to any one of claims 1 to 3, wherein the solvent is a hydrocarbon solvent.