JP2014181145A - Method of manufacturing cyclic silane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method producing cyclic silane from a cyclic halosilane compound in good productivity and good reproductivity and also capable of easily achieving purification of the cyclic silane.SOLUTION: The method of manufacturing cyclic silane includes a pulverization process for pulverizing a solid cyclic halosilane compound and a reaction process for producing cyclic silane represented by the formula (1): SiR(1), where n is an integer of 3 to 10, and R represents hydrogen, an organic group having 1 to 10 carbon atoms or a silyl group, by contacting the resulting cyclic halosilane pulverized product with at least one kind selected from a hydride reducing agent and an organic metallic reaction agent.

Description

  The present invention relates to a method for producing cyclic silane, and more particularly to a method for producing cyclic silane efficiently.

  Thin film silicon is used for applications such as solar cells and semiconductors, and this thin film silicon has been conventionally produced by a vapor deposition method (CVD method) using monosilane as a raw material. In recent years, a new production method using hydrogenated polysilane has attracted attention in place of the CVD method. The method is a coating film forming method (liquid process) in which a hydrogenated polysilane solution is applied to a substrate and then baked. As a raw material of the hydrogenated polysilane solution, cyclopentasilane, which is a cyclic hydrogenated silane, is used. It is used. It has been reported that this cyclopentasilane becomes hydrogenated polysilane by UV irradiation (Non-patent Document 1).

  By the way, there is a possibility that hydrogenated polysilane can be synthesized by using a cyclic hydrogenated silane other than cyclopentasilane as a raw material. In addition to cyclopentasilane, cyclohexasilane is known as the cyclic hydrogenated silane. Cyclohexasilane is, for example, trichlorosilane and N, N, N ′, N ″, N ″ -pentaethyldiethylenetriamine (pedeta) or N, N, N ′, N′-tetraethylethylenediamine (Teeda). (Teeda)) is contacted with a tertiary polyamine to prepare a tetradecachlorocyclohexasilane dianion salt, and the cyclic silane precursor (cyclic halosilane compound) is reduced using the hydride reducing agent. (Patent Documents 1 and 2).

Japanese Patent No. 4519955 International Publication No. 2011/094191 Pamphlet

T. Shimoda et. Al., “Solution-processed silicon films and transistors”, Nature, 2006, vol. 440, p. 783

However, the reduction of the cyclic halosilane compound with a hydride reducing agent requires a long reaction time, and the productivity is not sufficient and the reproducibility is poor.
Accordingly, an object of the present invention is to produce a cyclic silane from a cyclic halosilane compound with good productivity and reproducibility.
Another object of the present invention is to provide a production method capable of easily achieving not only improvement of productivity and reproducibility but also purification of cyclic silane.

  As a result of diligent studies to solve the above problems, the present inventors use a cyclic halosilane compound as a raw material as a solid, because the reduction reaction has low productivity and poor reproducibility. I thought that it was because of non-uniformity. Therefore, investigations were made to improve productivity and reproducibility by dissolving cyclic halosilane compounds.

  On the other hand, the cyclic silane as a product is generally more soluble in the reaction solvent than the raw material cyclic halosilane. Therefore, if the raw material cyclic halosilane is used as a solid and the reaction is made heterogeneous, by filtering after the reaction, unreacted raw material can be removed from the cyclic silane (product) dissolved in the reaction solvent by, for example, filtration. It can be removed by a simple method. Since the product, cyclic silane, is an extremely unstable compound, the fact that unreacted raw materials can be easily removed in this way enables rapid isolation by simplification of the process. This is very important from the viewpoint of suppressing decomposition. If the cyclic halosilane compound is dissolved, removal of the unreacted raw material becomes difficult. Therefore, it has been difficult to achieve both the productivity and reproducibility of the reduction reaction and the simple purification of the product.

  Therefore, as a result of further investigation, the present inventors have found that the cyclic halosilane compound is used in a heterogeneous system while remaining in a solid state, but there is room for improvement in its form. In other words, the cyclic halosilane compound used as a raw material was found to be extremely stable compared to the product cyclic silane, and it was not decomposed even when further pulverized, and the cyclic halosilane compound dissolved in the reaction solvent even when finely pulverized. On the other hand, even if it is not dissolved, if it is made fine, the reaction itself proceeds stably, and even if it remains as an unreacted substance after completion of the reaction, it can be removed by simple solid-liquid separation means such as filtration. Completed the invention.

That is, the method for producing the cyclic silane of the present invention includes:
A crushing step of crushing a solid cyclic halosilane compound;
The obtained cyclic halosilane pulverized product is brought into contact with at least one selected from a hydride reducing agent and an organometallic reactant, and the following formula (1):
Si _n R _2n (1)
(In the formula, n is an integer of 3 to 10, and R represents hydrogen, an organic group having 1 to 10 carbon atoms, or a silyl group.)
The reaction process of producing | generating cyclic silane represented by these is included (invention 1).
In the present invention, it is preferable that a reaction step is included after the pulverization step, a classification step is included after the pulverization step, and a particle size of the pulverized cyclic halosilane is 300 μm or less by the classification step.
The present invention also provides:
A cyclic halosilane compound having a size of 300 μm or less is brought into contact with at least one selected from a hydride reducing agent and an organometallic reactant, and the following formula (1):
Si _n R _2n (1)
(In the formula, n is an integer of 3 to 10, and R represents hydrogen, an organic group having 1 to 10 carbon atoms, or a silyl group.)
The manufacturing method (invention 2) of the cyclic silane characterized by including the reaction process of producing | generating cyclic silane represented by these is also included.
In this invention, in the said invention 1 and 2, it is preferable that the particle size of the cyclic | annular halosilane compound used at a reaction process is 20 micrometers or more. The reaction step is preferably carried out in the presence of a solvent, and the solvent is particularly preferably an ether solvent. In the reaction step, it is a more desirable embodiment to carry out the reaction while dropping at least one of at least one selected from a cyclic halosilane compound or a hydride reducing agent and an organometallic reactant.
Further, the present invention (Invention 1 and 2) includes a purification step of cyclic silane produced in the reaction step,
This purification step desirably includes a solid-liquid separation step of removing solids from the liquid containing cyclic silane. And it is a more desirable aspect that the said refinement | purification process includes at least one of the light boiling component distillation process which removes a light boiling impurity from cyclic silane, and the cyclic silane distillation process which removes a high boiling impurity from cyclic silane.
The present invention also includes cyclic halosilane particles having a particle size of 20 μm or more and 300 μm or less.

  According to the present invention, the cyclic halosilane compound is used in a finer form than before without dissolving the cyclic halosilane compound in the reaction solvent, so that the cyclic silane can be produced with high yield, and the product cyclic silane can be easily obtained. It can be purified. Thereby, it becomes possible to easily produce cyclic silane.

First, the outline of the method for producing a cyclic silane according to the present invention will be described.
In the following description, “cyclic hydrogenated silane” means a compound in which a silicon element constituting a monocyclic ring is unsubstituted in a compound having a monocyclic ring constituted by a silicon element. In addition, “cyclic organosilane” refers to a compound having a monocyclic ring composed of silicon elements, in which at least a part of hydrogen atoms bonded to silicon atoms constituting the monocyclic ring are substituted with other substituents (organic Or a silyl group). In addition, “cyclic silane” means a compound having a monocyclic ring composed of silicon element, and includes both the cyclic hydrogenated silane and the cyclic organosilane.
The cyclic halosilane compound means a compound in which at least a part of the silicon element constituting the elemental ring is substituted with halogen in the compound having a elemental ring composed of the silicon element. That is, it becomes a compound which becomes a precursor when producing cyclic hydrogenated silane or cyclic organosilane. The cyclic halosilane compound may be a salt or a complex. Details of the cyclic halosilane compound will be described in detail below.

  In the present invention, the cyclic silane is produced by reacting a cyclic halosilane compound with at least one selected from a hydride reducing agent and an organometallic reactant. That is, the cyclic hydrogenated silane is produced by reducing a precursor cyclic halosilane compound using a hydride reducing agent, and the cyclic organosilane is reacted with an organometallic reagent (in some cases, organic Reaction using both metal reactant and hydride reducing agent). Hereinafter, “at least one selected from a hydride reducing agent and an organometallic reactant” may be simply referred to as “nucleophilic agent”.

  And in this invention, when it uses for the subsequent reaction process (Reduction reaction using a hydride reducing agent, Organic group substitution reaction using an organometallic reagent), it has the characteristics in the point refine | miniaturized beforehand. By miniaturizing the cyclic halosilane compound, it is possible to achieve both a simple separation from the product cyclic silane while maintaining the reactivity with the hydride reducing agent and the organometallic reactant.

≪Cyclic silane≫
Cyclic silane is a compound having a monocyclic ring composed of silicon element. Specifically, the following formula (1):
Si _n R _2n (1)
(In the formula, n is an integer of 3 to 10, and R represents hydrogen, an organic group having 1 to 10 carbon atoms, or a silyl group.)
It is a compound represented by these.

  In the formula (1), n means the number of silicon atoms constituting the monocyclic ring, and the number of atoms n constituting the monocyclic ring is usually 3 to 10. The number of atoms n constituting the monocyclic ring is not particularly limited, but is preferably 4 or more, more preferably 5 or more, and preferably 9 or less, more preferably 8 or less. More preferably, it is 7 or less. Since it is useful for forming thin film silicon, it is most preferable that the number of silicon atoms constituting the elemental ring is 6 (that is, n is 6).

  The cyclic silane produced by the present invention is, for example, a cyclic hydrogenated silane in which R is a hydrogen atom in the formula (1), or an organic group having 1 to 10 carbon atoms or silyl in the formula (1). Examples thereof include cyclic organosilanes.

  Examples of the organic group of the cyclic organosilane include an alkyl group having 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and still more preferably 1 to 6 carbon atoms; Preferred examples include aryl groups having 6 to 9 carbon atoms, more preferably 6 to 8 carbon atoms; and more specifically, methyl groups, ethyl groups, propyl groups, iso-propyl groups, and n-butyl groups. Group, sec-butyl group, pentyl group, hexyl group, octyl group and phenyl group.

  Examples of the silyl group of the cyclic organosilane include a trimethylsilyl group, a triethylsilyl group, a triiso-propylsilyl group, a tert-butyldimethylsilyl group, a tert-butyldiphenylsilyl group, and a triphenylsilyl group.

≪Cyclic halosilane compound≫
Cyclic halosilane compounds used as raw materials for cyclic silanes generate cyclic silanes by reactions using hydride reducing agents and organometallic reagents (in some cases, reactions using both organometallic and hydride reducing agents). A compound that can be used is used. For example, one or two of the remaining two bonds of silicon constituting the monocyclic ring are formed by connecting silicon atoms with n silicon atoms to form a monocyclic ring ( In particular, a compound having a cyclic halosilane structure in which a halogen atom is bonded to 2). Further, as the cyclic halosilane compound, the compound having the cyclic halosilane structure further contains a halogen atom to form an anion structure as a whole, and a salt formed by the formed anion and a paired cation (that is, cyclic halosilane) Salt having a structure). In the present invention, the cyclic halosilane compound is preferably a salt having a cyclic halosilane structure because synthesis is simple and can be stably stored as a precursor. Hereinafter, in the present specification, a compound having a cyclic halosilane structure and a salt having a cyclic halosilane structure are collectively referred to as a cyclic halosilane compound.

Examples of the salt having a cyclic halosilane structure include a tetradecachlorocyclohexasilane dianion ([Si] in which a monocyclic ring (6-membered ring) composed of 6 silicon atoms is dianioned with 14 chlorine atoms. ₆ Cl ₁₄ ^2- ]), and a salt containing tetradecabromocyclohexasilane dianion ([Si ₆ Br ₁₄ ^2- ]). The counter ion of the dianion is not limited as long as it can form a stable salt with the dianion, and examples thereof include compounds in which a tertiary polyamine and a chlorosilane residue are bonded, and oniums.

  Examples of the tertiary polyamine include N, N, N ′, N ″, N ″ -pentaethyldiethylenetriamine (referred to as “pedeta”), an alkylene group (particularly an ethylene group, etc.) Are preferably alkylene groups having 1 to 6 carbon atoms) and an alkyl group (particularly, an alkyl group having 1 to 6 carbon atoms such as an ethyl group is preferably bonded). The number of repeating units of the alkylene amine is, for example, preferably 2 or more, more preferably 2 to 6, and still more preferably 2 to 4. The chlorosilane residue is a chlorosilane in which the tertiary polyamine, chlorine atom and hydrogen atom are coordinated to a silicon atom.

Examples of the oniums include phosphoniums (R ³ ₄ P (R ³ is an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 20 carbon atoms)), ammonium, and the like And the like (R ³ ₄ N (R ³ is an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 20 carbon atoms)) and the like.

≪Method for producing cyclic silane≫
<Preparation of cyclic halosilane compound>
Cyclic silane is produced by bringing the cyclic halosilane compound into contact with at least one selected from a hydride reducing agent and an organometallic reactant. In the present invention, the solid cyclic halosilane compound used as a raw material is subjected to these reaction steps (reduction reaction using a hydride reducing agent or an organometallic reactant (in some cases, both an organometallic reactant and a hydride reducing agent are used). It is characterized in that it is refined in advance when it is subjected to an organic group substitution reaction) using (reaction).

  Examples of the method for refining the cyclic halosilane compound include a method of pulverizing a solid cyclic halosilane compound. The method for pulverizing the solid cyclic halosilane compound is not particularly limited. For example, a method for grinding the cyclic halosilane compound using a mortar or the like; a pulverizer such as a ball mill, a disk mill, a bead mill, or a jet mill is used. Method; etc. may be adopted as appropriate. Among them, if the amount of the sample is small, it is preferable to employ a method of crushing using a mortar. If the number of samples is large, it is desirable to use a pulverizer, and a ball mill is particularly preferable because the operation is simple.

  When subjected to the reaction step, the particle size of the cyclic halosilane compound is, for example, preferably 300 μm or less, more preferably 250 μm or less, still more preferably 200 μm or less, and preferably 20 μm or more. Preferably it is 53 micrometers or more, More preferably, it is 100 micrometers or more. When the particle diameter of the cyclic halosilane compound used in the reaction step exceeds 300 μm, the reaction rate in the subsequent reaction step becomes slow, and the productivity may be reduced. On the other hand, if the particle diameter is smaller than 20 μm, the residual cyclic halosilane compound may pass through the filtration filter, making it difficult to separate the unreacted cyclic halosilane compound from the reaction mixture. The cyclic halosilane compound (for example, a pulverized product of cyclic halosilane) is preferably in the form of particles.

  The particle diameter of the cyclic halosilane compound can be easily controlled within the above range by using, for example, a standard sieve of JIS Z8801 (the particle size of 300 μm or less corresponds to a 50-mesh sieve component).

  In the present invention, it is also possible to use a commercially available cyclic halosilane compound whose particle diameter is adjusted in advance, or a cyclic halosilane compound whose particle diameter is adjusted within a predetermined range by a method other than pulverization. . By using a cyclic halosilane compound in which these particle sizes are adjusted, the pulverization step can be omitted.

  In the present invention, after the pulverizing step of pulverizing the cyclic halosilane compound, or a classification step for classifying a commercially available cyclic halosilane compound may be performed. By performing the classification step, it is preferable because the particle size of the cyclic halosilane compound can be adjusted within a predetermined range (for example, 20 μm to 300 μm, more preferably 53 μm to 250 μm, still more preferably 100 μm to 200 μm).

  The classification method is not particularly limited, but various classification methods such as sieving classification, gravity classification, inertia classification, dry classification such as centrifugal classification (cyclonic classification); wet classification such as sedimentation classification and hydraulic classification; Can be adopted as appropriate. In the present invention, dry classification is preferable because the cyclic halosilane compound is not dissolved. In particular, it is desirable to employ sieving classification because classification accuracy is high and operation is simple.

  A cyclic halosilane compound (hereinafter referred to as a “fine cyclic halosilane compound”) having a particle diameter adjusted within a predetermined range can be used as a solid in the reaction process in consideration of the balance between solubility in a solvent and reactivity. It is desirable to provide.

<Reduction reaction>
A hydride reducing agent is used for the reduction of the cyclic halosilane compound. The hydride reducing agent is not particularly limited. For example, aluminum-based reducing agents such as lithium aluminum hydride, diisobutylaluminum hydride, sodium bis (2-methoxyethoxy) aluminum hydride; sodium borohydride, hydrogen Metal hydrides such as boron-based reducing agents such as lithium triethylborohydride. In addition, these hydride reducing agents may use only 1 type and may use 2 or more types together.

  The amount of the hydride reducing agent used may be appropriately set. For example, the molar equivalent of the hydride reducing agent per one silicon-halogen bond in the fine cyclic halosilane compound may be at least 1 equivalent, preferably Is from 2 equivalents to 50 equivalents, more preferably from 5 equivalents to 40 equivalents, and even more preferably from 10 equivalents to 30 equivalents. If the amount of the hydride reducing agent is too large, it takes time for the post-treatment and the productivity tends to decrease. Moreover, since there exists a tendency for a yield to fall when there is too little quantity of a hydride reducing agent, it is unpreferable.

<Organic group substitution reaction>
An organometallic reactant is used for the organic group substitution reaction of the cyclic halosilane compound. The organometallic reactant is not particularly limited, and examples thereof include a Grignard reagent or an organolithium reagent.

  Examples of Grignard reagents include alkylmagnesium halides such as methylmagnesium bromide; arylmagnesium halides such as phenylmagnesium bromide; and the like. These Grignard reagents may be used alone or in combination of two or more.

  Examples of the organic lithium reagent include alkyl lithium compounds such as methyl lithium, n-butyl lithium, sec-butyl lithium, and tert-butyl lithium; aryl lithium compounds such as phenyl lithium; These organolithium reagents may be used alone or in combination of two or more.

  What is necessary is just to set the usage-amount of the said organometallic reactant suitably, for example, the molar equivalent of the organometallic reactant with respect to one silicon-halogen bond of the said fine cyclic | annular halosilane compound should just be at least 1 equivalent or more. Preferably, it is 1.1 equivalents or more and 10 equivalents or less, More preferably, it is 1.2 equivalents or more and 5 equivalents or less, More preferably, it is 1.5 equivalents or more and 3 equivalents or less. If the amount of the organometallic reactant is too large, post-treatment takes time and the productivity tends to decrease. On the other hand, if the amount of the organometallic reactant is too small, the yield tends to decrease, such being undesirable. In addition, in the organic group substitution reaction, not only the organometallic reactant described above but also a hydride reducing agent can be used in combination.

<Reaction procedure, etc.>
Since the solvents and reaction procedures used in the reduction reaction and the organic group substitution reaction are common, they will be collectively described below. In the reduction reaction and the organic group substitution reaction, the cyclic halosilane compound obtained by the above-mentioned pulverization step of the cyclic halosilane compound; the cyclic halosilane compound obtained by the classification step; Fine cyclic halosilane compounds such as can be used.

  These reaction steps are all carried out in the presence of a solvent. Examples of the solvent include various solvents such as hydrocarbon solvents such as hexane and toluene; ether solvents such as diethyl ether, tetrahydrofuran, cyclopentyl methyl ether, diisopropyl ether, and methyl tertiary butyl ether. These solvent may use only 1 type and may use 2 or more types together. Among them, the solvent used in the reaction step is preferably an ether solvent, and more preferably cyclopentyl methyl ether. Even if the ether solvent is a heterogeneous reaction system, it is superior to other solvents in that the reaction proceeds with high yield and reproducibility simply by making the cyclic halosilane compound fine. In addition, the reaction liquid after the reaction is superior to other solvents in that it can be precipitated as a solid while dissolving the target cyclic silane, without dissolving impurities (for example, cyclic halosilane compounds). ing. Therefore, it is preferable because the cyclic silane can be efficiently isolated by solid-liquid separation such as filtration, and thereby high-purity cyclic silane can be efficiently produced.

  Cyclic silane is an oxygen- and water-absorptive substance. For this reason, it is desirable to purify the solvent used in the reaction step by distillation or dehydration before the reaction in order to remove water and dissolved oxygen contained in the solvent. The water content of the solvent is, for example, preferably 100 ppm or less on a mass basis, more preferably 50 ppm or less, and still more preferably 20 ppm or less. Further, the water content of the solvent is preferably 0 ppm or more, but since it may be difficult in practice to set the water content to 0 ppm, the water content of the solvent is preferably at least 0.01 ppm. It is.

  The amount of the solvent used in the reaction step is preferably adjusted so that the concentration of the cyclic halosilane compound is 0.005 mol / L or more and 1 mol / L or less, more preferably 0.01 mol / L or more and 0.7 mol. / L or less, more preferably 0.025 mol / L or more and 0.5 mol / L or less. When the concentration of the cyclic halosilane compound exceeds 1 mol / L, the heat generated by the reaction may not be sufficiently removed. In addition, since the product is difficult to dissolve, problems such as a decrease in reaction rate may occur. On the other hand, when the concentration of the cyclic halosilane compound is less than 0.005 mol / L, the amount of the solvent to be distilled off when the solvent and the target product are separated after the reaction increases, and thus the productivity tends to decrease. Therefore, it is not preferable.

  The reaction step can be performed by bringing a fine cyclic halosilane compound into contact with a nucleophile. The contact between the fine cyclic halosilane compound and the nucleophile is preferably carried out in the presence of a solvent. Examples of methods for contacting the cyclic halosilane compound and the nucleophile in the presence of a solvent include 1) cyclic halosilane. Each of the compound and the nucleophile is dissolved or dispersed in advance in a solvent to prepare a solution (or dispersion) of the cyclic halosilane compound and a solution (or dispersion) of the nucleophile, and then these solutions ( Or a dispersion method), and 2) a contact method such as a method in which a cyclic halosilane compound and a nucleophile are directly or sequentially added to a solvent. Among them, it is preferable to employ the contact method 1) because of high reaction efficiency.

  In contacting the cyclic halosilane compound and the nucleophile in the reaction step, it is preferable to drop at least one (nucleophilic agent) selected from a cyclic halosilane compound or a hydride reducing agent and an organometallic reactant. As the dropping method, for example, (I) at least one of a cyclic halosilane compound and a nucleophile or a mixture thereof is charged in a reaction system for carrying out the reaction, and the other solution (or dispersion) not charged in the reactor therein. (II) A solution (or dispersion) of a cyclic halosilane compound and a solution (or dispersion) of a nucleophile are dropped simultaneously or sequentially into an empty reaction system (reactor). And adding it. Thus, when the reaction raw material is added dropwise, the dropping rate can be controlled, so that the amount of heat generated by the reaction can be controlled. Thereby, for example, it is expected that productivity can be improved, such as miniaturization of a capacitor or the like.

The solute concentration of the solution or dispersion medium containing the cyclic halosilane compound as a solute is preferably 0.005 mol / L or more, more preferably 0.01 mol / L or more, and further preferably 0.02 mol / L or more. If the solute concentration is too low, the amount of solvent that must be distilled off when isolating the target product increases, which may reduce productivity. On the other hand, the upper limit of the solute concentration is preferably 1 mol / L or less, more preferably 0.8 mol / L or less, and still more preferably 0.6 mol / L or less. If the solute concentration (particularly the solute concentration of the solution or dispersion used for the dropwise addition) is too high, the amount of heat generated in the reaction tends to be difficult to control.
In addition, the solute concentration of each solution or dispersion is adjusted so that the solution mass or the dispersion solution containing the cyclic halosilane compound as the solute and the solution or dispersion solution containing the nucleophilic agent as the solute have substantially the same dissolved mass. It is preferable to do.

  The temperature at the time of dropping (specifically, the temperature of the solution or dispersion used for dropping and / or the temperature of the solution or dispersion charged in the reactor) is preferably −30 ° C. or more and 80 ° C. or less. More preferably, it is 0 degreeC or more and 50 degrees C or less, More preferably, it is 10 degreeC or more and 40 degrees C or less.

  Although the dropping rate depends on the concentration in the solution or dispersion, for example, 0.01 mL / min to 100 mL / min is preferable, more preferably 0.2 mL / min to 50 mL / min, and still more preferably 1 mL / min. It is 20 mL / min or more.

  Although the dropping time is not particularly limited, from the viewpoint of productivity, for example, it is preferably 10 minutes or longer and 20 hours or shorter, more preferably 30 minutes or longer and 10 hours or shorter, and further preferably 1 hour or longer and 6 hours or shorter. is there.

  The reaction temperature during the reaction may be appropriately set according to the kind of the cyclic halosilane compound and the nucleophile, and is usually preferably −20 ° C. or higher, more preferably −10 ° C. or higher, and further preferably 0 ° C. or higher. Yes, it is preferably 150 ° C. or lower, more preferably 100 ° C. or lower, still more preferably 70 ° C. or lower.

  The reaction time may be appropriately determined according to the progress of the reaction, and is preferably, for example, 10 minutes to 72 hours, more preferably 1 hour to 48 hours, and further preferably 2 hours to 24 hours. Below time.

  In the reaction step, it is preferable that all the cyclic halosilane compounds as raw materials are reacted, but when a part of them remains unreacted, the unreacted substances remain undissolved, while the produced cyclic hydrogenated silane It is desirable that all are dissolved.

  Cyclic silane is an oxygen-free substance. Therefore, it is desirable that the reaction process be performed in an atmosphere of an inert gas such as nitrogen gas or argon gas.

<Purification process>
In the method for producing a cyclic silane of the present invention, it is desirable to carry out a purification step for purifying the cyclic silane (cyclic hydrogenated silane compound or cyclic organosilane compound) generated in the reaction step after the reaction step. In the purification step, for example, a solid-liquid separation step of separating solids (impurities such as by-produced salts) in the reaction solution from a solution containing cyclic silane may be performed. Examples of solid-liquid separation methods include filtration, centrifugation, decantation, and the like, and filtration is more preferable because separation is simple.

  In the solution after the solid-liquid separation step, not only cyclic silane that is liquid at room temperature, but also light-boiling impurities having a boiling point lower than that of cyclic silane and high-boiling impurities having a boiling point higher than that of cyclic silane are dissolved. Therefore, in the separation step, after the solid-liquid separation step, a light boiling component distillation step for removing light boiling impurities in the solvent from the cyclic silane; a cyclic silane distillation step for removing high boiling impurities from the cyclic silane; May be implemented as appropriate. Thus, since the purity of cyclic silane can be raised more by distilling off the light boiling component in a solvent or separating a high boiling impurity by distillation, it is preferable.

  The method for distilling off the light boiling impurities is not particularly limited, but various separation methods such as distillation and concentration may be employed. Further, it is desirable to employ distillation when separating high boiling impurities from cyclic silane. In the purification step, both the light boiling component distillation step and the cyclic silane distillation step may be performed, or either the light boiling component distillation step or the cyclic silane distillation step may be performed. Moreover, it is also possible to implement only the solid-liquid separation process described above without performing these liquid-liquid separation processes.

  The cyclic silane of the present invention can be used as a thin film silicon raw material, and is suitably used for applications such as solar cells and semiconductors.

  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.

Example 1
Under a nitrogen gas atmosphere, 12.6 g (330 mmol) of lithium aluminum hydride as a hydride reducing agent and 500 mL of cyclopentyl methyl ether (CPME) as a solvent were added to a two-necked flask to prepare a slurry solution of lithium aluminum hydroxide.
Separately, [Pedeta · SiH ₂ Cl ⁺ ] ₂ [Si ₆ Cl ₁₄ ²⁻ ] as a cyclic halosilane compound was ground in a mortar, passed through a 50 mesh (standard size 300 μm) sieve, and then passed over a 20 μm filter. The remaining crystals were collected.
Under an argon gas atmosphere, 95.0 g (74.1 mmol) of the classified cyclic halosilane compound and 2 L of cyclopentyl methyl ether (CPME) were placed in a four-necked flask (3 L) and stirred at room temperature.
Into this four-necked flask, the previously prepared slurry of lithium aluminum hydroxide was added dropwise using a dropping funnel over 3 hours, and after completion of the addition, the reaction was carried out by stirring at room temperature for 8 hours. During the reaction, argon gas was circulated in the flask and passed through two traps containing an aqueous potassium hydroxide solution, whereby silane gas generated as a by-product was captured, detoxified and discharged.
After completion of the reaction, the reaction solution was filtered using a glass filter having a pore diameter of 20 μm under a nitrogen gas atmosphere, and the solvent was distilled off from the obtained filtrate under reduced pressure to produce cyclohexasilane as a colorless transparent liquid. The yield of cyclohexasilane was 90%.

Comparative Example 1
Example 1 except that the step of grinding a cyclic halosilane compound ([Pedeta · SiH ₂ Cl ⁺ ] ₂ [Si ₆ Cl ₁₄ ^2- ]) with a mortar and the sieving step for passing through a mesh sieve are omitted. By this method, cyclohexasilane was produced as a colorless and transparent liquid. The particle size of the cyclic halosilane compound ([Pedeta · SiH ₂ Cl ⁺ ] ₂ [Si ₆ Cl ₁₄ ²⁻ ]) used in the reaction step was about 600 μm. The yield of the obtained cyclohexasilane was 64%.

Claims (11)

A crushing step of crushing a solid cyclic halosilane compound;
The obtained cyclic halosilane pulverized product is brought into contact with at least one selected from a hydride reducing agent and an organometallic reactant, and the following formula (1):
Si _n R _2n (1)
(In the formula, n is an integer of 3 to 10, and R represents hydrogen, an organic group having 1 to 10 carbon atoms, or a silyl group.)
The manufacturing method of cyclic silane characterized by including the reaction process which produces | generates cyclic silane represented by these.   The manufacturing method of the cyclic silane of Claim 1 including a reaction process after the said grinding | pulverization process.   The method for producing a cyclic silane according to claim 1, further comprising a classification step after the pulverization step, wherein the particle size of the pulverized cyclic halosilane is 300 μm or less by the classification step. A cyclic halosilane compound having a size of 300 μm or less is brought into contact with at least one selected from a hydride reducing agent and an organometallic reactant, and the following formula (1):
Si _n R _2n (1)
(In the formula, n is an integer of 3 to 10, and R represents hydrogen, an organic group having 1 to 10 carbon atoms, or a silyl group.)
The manufacturing method of cyclic silane characterized by including the reaction process which produces | generates cyclic silane represented by these.   The method for producing a cyclic silane according to any one of claims 1 to 4, wherein a particle diameter of the cyclic halosilane compound used in the reaction step is 20 µm or more.   The method for producing a cyclic silane according to claim 1, wherein the reaction step is performed in the presence of a solvent.   The method for producing a cyclic silane according to claim 6, wherein the solvent is an ether solvent.   The production of cyclic silane according to any one of claims 1 to 7, wherein in the reaction step, at least one selected from a cyclic halosilane compound or a hydride reducing agent and an organometallic reactant is added dropwise. Method. Including a purification step of cyclic silane produced in the reaction step,
The method for producing cyclic silane according to any one of claims 1 to 8, wherein the purification step includes a solid-liquid separation step of removing a solid from a liquid containing cyclic silane. The purification step comprises
The method for producing cyclic silane according to claim 9, comprising at least one of a light boiling component distillation step for removing light boiling impurities from the cyclic silane and a cyclic silane distillation step for removing high boiling impurities from the cyclic silane.   Cyclic halosilane particles having a particle size of 20 μm or more and 300 μm or less.