JP2013203601A - Method for producing cyclohexasilane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing cyclohexasilane that simplifies steps to improve productivity and saves spaces over the entire production device when a series of reactions for producing cyclohexasilane from trihalosilane are successively carried out.SOLUTION: There is provided a method for producing cyclohexasilane in which the cyclohexasilane is produced by synthesizing a tetradecahalocyclohexasilane-dianion-containing compound by cyclizing and coupling trihalosilane, filtering the dianion-containing compound out of the synthesized liquid, synthesizing cyclohexasilane by reducing the filtered dianion-containing compound, and filtering insoluble matter out of the cyclohexasilane synthesized liquid. A mesh member fitted in a cyclohexasilane synthesis container or downstream from a discharge port of the synthesis container performs both the filtration of the dianion-containing compound and the filtration of the insoluble matter from the cyclohexasilane synthesized liquid.

Description

  The present invention relates to a method for continuously producing cyclohexasilane from trihalosilane with good productivity.

  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 cyclic hydrogenated silane has attracted attention in place of the CVD method. This manufacturing method is a coating film forming method (liquid process) in which a hydrogenated polysilane solution is applied to a substrate and baked, and cyclopentasilane is used as a raw material for preparing the hydrogenated polysilane solution. Cyclopentasilane is commercially available and is known to be hydrogenated polysilane by UV irradiation. However, cyclopentasilane is very expensive because it requires a multi-step synthesis and purification process using an expensive water-free reagent. Thus, cyclohexasilane has attracted attention as an alternative material for cyclopentasilane.

  Cyclohexasilane is trichlorosilane, N, N, N ′, N ″, N ″ -pentaethyldiethylenetriamine (peda) or N, N, N ′, N′-tetraethylethylenediamine (teeda). The salt of tetradecachlorocyclohexasilane dianion can be prepared by cyclization coupling in the presence of a tertiary polyamine such as)), and the salt can be reduced by contacting with the metal hydride reducing agent. Known (Patent Document 1).

Japanese Patent No. 4519955

  According to the method described in Patent Document 1, since tetradecachlorocyclohexasilane dianion salt is obtained as a solid in the cyclization coupling reaction, it is necessary to filter it from the reaction solution after the coupling reaction. In the subsequent reduction reaction, the target product, cyclohexasilane, dissolves in the reaction solution, but the by-product (metal salt of the reducing agent) is insoluble. Run) must be collected. Therefore, when performing a series of reactions for producing cyclohexasilane from trichlorosilane, a vessel for performing a cyclization coupling reaction, a first filtration device, a vessel for carrying out a reduction reaction, and a second filtration device are sequentially provided. , Complicated operations (for example, filtration after the cyclization coupling reaction, charging of the filtrate into another reaction vessel, subsequent reduction reaction, and subsequent filtration) had to be performed.

  The present invention has been made by paying attention to the above-described circumstances, and its purpose is to simplify the process and improve productivity in continuously performing a series of reactions for producing cyclohexasilane from trihalosilane. An object of the present invention is to provide a method for producing cyclohexasilane that can be improved and can save space in the whole production apparatus.

  The process for producing cyclohexasilane of the present invention that can achieve the above-mentioned object is a compound comprising a tetradecahalocyclohexasilane / dianion containing compound (hereinafter referred to simply as “halocyclosilane salt”). The dianion-containing compound (halocyclosilane salt) is filtered from the synthesis solution, and the dianion-containing compound (halocyclosilane salt) is reduced to synthesize cyclohexasilane. The cyclohexasilane synthesis solution is a method for producing cyclohexasilane by filtering off insoluble matter contained in the cyclohexasilane synthesis solution, and is a mesh member attached in the cyclohexasilane synthesis vessel or downstream from the discharge port of the synthesis vessel. The point is that both the filtration of the dianion-containing compound and the insoluble matter from the cyclohexasilane synthesis solution are separated by filtration. Those having.

  In the present invention, the mesh member is preferably attached in a cyclohexasilane synthesis container. Further, the cyclohexasilane synthesis container has an inner and outer cylinder double structure, and the mesh member is an inner cylinder. It is preferable to be formed. Moreover, it is preferable that the mesh pore diameter of the said mesh member is 3-100 micrometers.

  In the present invention, the dianion-containing compound synthesis container and the cyclohexasilane synthesis container are the same or different, and the dianion-containing compound synthesis container and the cyclohexasilane synthesis container are accommodated in one explosion-proof booth. preferable. Furthermore, it is preferable to control the inside of the explosion-proof booth to an inert gas atmosphere having an oxygen concentration of 10% by volume or less and a moisture concentration of 10 ppm (volume basis) or less.

According to the present invention, when cyclohexasilane is produced from trihalosilane via a halocyclosilane salt such as tetradecachlorocyclohexasilane dianion salt, in the cyclohexasilane synthesis vessel used for reduction of the halocyclosilane salt or the synthesis A mesh member attached downstream from the outlet of the vessel performs both the filtration of the halocyclosilane salt and the insoluble matter from the cyclohexasilane synthesis solution. In this case, it is possible to improve the productivity by simplifying the process and to obtain the effect that the entire manufacturing apparatus can be saved in space. That is, according to the present invention, in a predetermined space in which all of the filtration of the halocyclosilane salt, the synthesis of cyclohexasilane (reduction reaction), and the separation of insoluble matter from the resultant synthesis solution are separated ( In a cyclohexasilane synthesis container, etc.), space saving of the production equipment can be achieved, and for example, complicated operations such as recharging the filtered halocyclosilane salt into another synthesis container can be simplified, Productivity is also improved.
In addition, since cyclohexasilane is a water- and oxygen-free substance, at least the reduction reaction and the filtration of insoluble matter after the reduction reaction must be performed in a completely inert gas atmosphere. In view of such circumstances, it can be said that it can be an advantageous effect that it can be performed in a predetermined space (such as in a cyclohexasilane synthesis container) from the reduction reaction to the subsequent filtration operation (separation of insoluble matter).
Further, when the cyclohexasilane synthesis container has an inner / outer cylinder double structure and the mesh member is formed in a removable inner cylinder, there is an advantage that maintenance of the mesh member is facilitated. .

  The dianion-containing compound synthesis vessel and the cyclohexasilane synthesis vessel are accommodated in one explosion-proof booth, and the inert gas having an oxygen concentration of 10% by volume or less and a moisture concentration of 10 ppm (volume basis) or less in the explosion-proof booth. When the atmosphere is controlled, the oxidation reaction or hydrolysis reaction of the product cyclohexasilane can be suppressed even when there is leakage from the explosion-proof booth into the synthesis container.

FIG. 1 is a schematic view for explaining a production line for performing the production method of the present invention. FIG. 2 is a schematic cross-sectional view showing an example of a synthetic container having a double inner / outer cylinder structure that can be used in the production method of the present invention.

  In the present invention, a halocyclosilane salt is synthesized by cyclization coupling of trihalosilane, and the halocyclosilane salt is filtered from the synthesis solution (halocyclosilane salt synthesis step, first filtration), The obtained halocyclosilane salt is reduced to synthesize cyclohexasilane, and a process of separating insoluble matters contained in the cyclohexasilane synthesis solution (cyclohexasilane synthesis process, second filtration) is continuously performed. To produce cyclohexasilane. Moreover, in the present invention, both the first filtration and the second filtration are performed with a mesh member attached in the cyclohexasilane synthesis container or on the downstream side from the discharge port of the synthesis container. If the mesh members used in the first filtration and the second filtration are made common in this way, two types of filtration can be performed by a series of operations within a predetermined space, which improves productivity and the entire manufacturing apparatus. Space saving. The predetermined space divided is a substantially sealed space, for example, including a space having an inlet and an outlet through which an inert gas is circulated, and specifically, a space (cyclohexane) to which a mesh member is attached. In a sasilane synthesis container).

In the present invention described above, the halocyclosilane synthesis and the cyclohexasilane synthesis may be performed in different reaction vessels or in the same reaction vessel. When the reaction is performed in different reaction vessels, for example, as shown in FIG. 1, a configuration in which a separately provided halocyclosilane salt synthesis vessel 1 and cyclohexasilane synthesis vessel 2 are directly connected by a line can be employed. As shown in FIG. 1, the halocyclosilane salt synthesis vessel 1 is provided upstream of the cyclohexasilane synthesis vessel 2, and both synthesis vessels 1 and 2 are connected in a liquid-tight manner by a pipe 3. In the example shown in the figure, the bottom of the halocyclosilane salt synthesis container 1 and the lid of the cyclohexasilane synthesis container 2 are connected by a pipe 3. However, liquid feeding from the synthesis container 1 to the synthesis container 2 (pressure feeding, etc.) ) Can be changed as appropriate as long as it can be performed smoothly. In the cyclohexasilane synthesis vessel 2, a tube 4 extending from an appropriate place (can bottom in the illustrated example) may be liquid-tightly connected to the concentrator 5 (in the illustrated example, the concentrator 5 is connected). The concentrator 5 includes a reaction solvent outlet 6 and a cyclohexasilane outlet 7.
When the halocyclosilane synthesis and the cyclohexasilane synthesis are performed in the same reaction vessel, the cyclohexasilane synthesis vessel 2 also serves as the halocyclosilane salt synthesis vessel 1 in FIG. Is no longer necessary.

  And in this invention, the mesh member is provided in the predetermined place mentioned above (in the cyclohexasilane synthesis container, the downstream side from the discharge port of this synthesis container, etc.). FIG. 1 is an example of a case where a mesh member is provided in the cyclohexasilane synthesis container 2. In particular, in the illustrated example, on the downstream side of the discharge channel in the container 2 (specifically, on the bottom of the can 2 of the container 2). A discharge port 10 is provided, and a mesh member 8 is attached to a location close to the discharge port, that is, at the bottom of the container 2. Moreover, when attaching a mesh member in the downstream from the discharge port of a cyclohexasilane synthesis container, a mesh member may be attached in the pipe | tube 4 (refer FIG. 1) extended from the discharge port 10, for example, A filter (not shown) may be connected to 4 in a fluid-tight manner, and a mesh member may be attached in the filter. When connecting a filter, the above-described concentrator 5 is connected to the downstream side of the filter. If a mesh member is attached in the cyclohexasilane synthesis container 2 or downstream of the discharge port of the container 2 as described above, a predetermined space in which two types of filtration are separated (that is, the cyclohexasilane synthesis container 2) In some cases, an internal space separated by the tube 4 and the concentrator 5) can be performed by a series of operations.

For example, when the production line shown in FIG. 1 is employed (that is, when halocyclosilane synthesis and cyclohexasilane synthesis are performed in different reaction vessels), first, a halocyclosilane salt synthesis vessel 1 is used for the cyclization coupling reaction of trihalosilane. To prepare a halocyclosilane salt synthesis solution (operation 1).
Next, a valve (not shown) attached to the outlet of the synthesis vessel 1 is opened, and the halocyclosilane salt synthesis solution in the synthesis vessel 1 is passed through the tube 3 in the slurry state containing the precipitated halocyclosilane salt. Transfer to the sasilane synthesis container 2 (operation 2).
Next, the transferred halocyclosilane salt synthesis solution is filtered (first filtration) with the mesh member 8 in the cyclohexasilane synthesis container 2 so that only the halocyclosilane salt is accommodated in the cyclohexasilane synthesis container 2. (Operation 3). This operation 3 can be easily performed by, for example, opening the valve 9 and opening the outlet 10 of the cyclohexasilane synthesis container 2. At this time, if necessary, the filtration efficiency may be improved by applying pressure from the upstream side of the mesh member or reducing pressure from the downstream side. In addition, when providing a mesh member downstream from the discharge port of the synthesis container, the halocyclosilane salt on the mesh member may be pumped into the cyclohexasilane synthesis container 2 after filtration.
Next, a reducing agent or a solvent necessary for the reduction reaction is put into the cyclohexasilane synthesis vessel 2 to reslurry the halocyclosilane salt (operation 4). At this time, before introducing a reducing agent or a solvent necessary for the reduction reaction into the synthesis container, an appropriate solvent that does not react with the reducing agent (for example, a reaction solvent used for the reduction reaction) is introduced into the container and drained. Therefore, it is preferable to wash the filtered halocyclosilane salt.
After the reduction reaction, the contents of the cyclohexasilane synthesis container 2 (cyclohexasilane synthesis solution) are those in which insolubles produced as a by-product are dispersed in a solution in which the produced cyclohexasilane is dissolved. Then, the cyclohexasilane synthesis solution is filtered through the mesh member 8 (second filtration), and by-products (insoluble matter) are separated on the mesh member 8, and the solution containing cyclohexasilane passes through the mesh member 8. To the concentrator 5 (operation 5). This operation 5 can be easily performed by, for example, opening the valve 9 and opening the outlet 10 of the cyclohexasilane synthesis container 2. At this time, if necessary, the filtration efficiency may be improved by applying pressure from the upstream side of the mesh member or reducing pressure from the downstream side. The insoluble matter filtered off here contains the tertiary polyamine salt (metal salt derived from the reducing agent) used in the cyclization coupling reaction, so it is recovered from the synthesis vessel and hydrolyzed, etc. Then, it can be reused in the cyclization coupling reaction as a tertiary polyamine.
Thereafter, the solvent is distilled off from the solution containing cyclohexasilane transferred to the concentrator 5 under reduced pressure, and the cyclohexasilane is recovered from the outlet 7 provided in the concentrator 5 (operation 6).

  The above operation can be carried out in the same manner in embodiments other than FIG. 1. For example, when halocyclosilane synthesis and cyclohexasilane synthesis are performed in the same reaction vessel, first, trihalosilane is synthesized in the cyclohexasilane synthesis vessel. Then, a halocyclosilane salt synthesis solution is prepared (operation 1 ′). Next, as in the above operation 3, the halocyclosilane salt synthesis solution in the container is filtered through the mesh member 8 (first filtration) so that only the halocyclosilane salt is contained in the cyclohexasilane synthesis container. Thereafter, operations 4 to 6 may be performed as described above.

  If the halocyclosilane synthesis and the cyclohexasilane synthesis are performed in the same reaction vessel, an advantage that the entire manufacturing apparatus can be saved more space can be obtained. On the other hand, when the halocyclosilane synthesis and the cyclohexasilane synthesis are performed in different reaction vessels, it is possible to reduce the contamination between the reactions and the labor of washing.

  Moreover, when attaching the attachment position of a mesh member in the downstream from the discharge port of a cyclohexasilane synthesis container, it can do similarly to the above except performing the 1st and 2nd filtration in the said downstream. The attachment position of the mesh member is preferably in the cyclohexasilane synthesis container (particularly on the downstream side of the discharge channel in the synthesis container). By attaching the mesh member in the synthesis container, clogging of the filtrate can be prevented and reslurry can be easily performed as compared with the case where the mesh member is provided downstream from the discharge port of the synthesis container.

  When attaching the mesh member in the cyclohexasilane synthesis container, the mesh member may be directly attached to the container main body, but it is composed of the container main body (outer cylinder) and the inner cylinder detachably accommodated inside the outer cylinder. Preferably, the inner and outer cylinders have a double structure, and at least a part (or all) of the inner cylinders are mesh members. Thereby, the maintenance of the mesh member 8 becomes easy.

  FIG. 2 shows an example of the synthetic container having the inner / outer cylinder double structure. In FIG. 2, the synthesis container 2 includes a bottomed outer cylinder 11 that constitutes a container body, and a bottomed inner cylinder 12 that is accommodated inside the outer cylinder 11. The inner cylinder 12 in the illustrated example is entirely or bottom made of a mesh member. And the bottom part of the inner cylinder 12 is being fixed by the fixing member 13 provided in the side surface of the container 2 so that the fixed space | interval may be kept from the discharge port 10 of the container 2 bottom part. In this way, by keeping a certain distance from the discharge port 10, clogging of the filtrate can be suppressed, and the filtration efficiency is improved. The distance from the discharge port 10 (the bottom of the synthesis container 2) to the bottom of the inner cylinder 12 is preferably 30% or less of the height of the synthesis container 2, for example.

  In FIG. 2, the outer side surface of the inner cylinder 12 is in contact with the outer cylinder 11, but a certain interval may be formed between the outer side surface of the inner cylinder 12 and the inner side surface of the outer cylinder 11. If it does in this way, the outer side surface of the inner cylinder 12 will also contribute to filtration, and the filtration area can be expanded. However, in the case where a certain distance is formed between the outer side surface of the inner cylinder 12 and the inner side surface of the outer cylinder 11, it is important that the liquid level of the reaction liquid to be stored does not exceed the upper end of the inner cylinder 12. . The distance between the outer side surface of the inner cylinder 12 and the inner side surface of the outer cylinder 11 is preferably, for example, 30% or less of the diameter of the synthesis container 2.

  In the synthetic container having the inner and outer cylinder double structure, the mesh member may be formed on the entire inner cylinder as shown in FIG. 2 or on the entire or a part of the bottom of the inner cylinder. It may be the whole or part of the side surface. At least in terms of filtration efficiency, when a predetermined interval is maintained between the bottom of the synthesis container and the bottom of the inner cylinder, the entire inner cylinder bottom is preferably a mesh member, and the inner cylinder outer side surface and the outer cylinder In the case where a predetermined distance is maintained between the inner side surface and the inner side surface, the entire surface of the inner cylinder side surface is preferably a mesh member.

  2 includes a raw material supply port 14, a shaft 15 and a stirring blade 16 for stirring the contents, a jacket 17 and a thermometer 18 for controlling the temperature of the contents, and an inert gas in the container. A gas supply pipe 19, a pressure gauge 20 and a valve for providing an atmosphere are provided. These may be provided as needed, and for example, the shape of the stirring blade 16 can be selected as appropriate. Although not shown, the synthesis container 2 shown in FIG. 1 may be provided with similar equipment.

  The material of the mesh member is not particularly limited as long as it has durability against each reaction and does not affect each reaction. For example, a mesh member formed of a material such as a metal such as stainless steel, ceramics such as an alumina sintered body, glass, or plastic such as fluororesin (fluorinated ethylene propylene) can be used. Among these, a fluororesin is preferable.

  The mesh pore diameter of the mesh member is preferably 3 to 100 μm, more preferably 5 μm or more, further preferably 10 μm or more, more preferably 90 μm or less, and further preferably 80 μm or less. If the mesh pore diameter is too small, clogging tends to occur during filtration. On the other hand, if the mesh pore diameter is too large, the filtration accuracy may be insufficient.

  In the present invention, it is preferable that the halocyclosilane salt synthesis vessel and the cyclohexasilane synthesis vessel are accommodated in one explosion-proof booth, and further, the oxygen concentration within the explosion-proof booth is 10% by volume or less (more It is preferable to control the inert gas atmosphere so that it is preferably 8% by volume or less, more preferably 5% by volume or less, and a water concentration of 10 ppm (volume basis) or less (more preferably 8 ppm or less, more preferably 5 ppm or less). Thereby, even when there is leakage from the explosion-proof booth into the synthesis container, the oxidation reaction or hydrolysis reaction of the product cyclohexasilane can be suppressed. The explosion-proof booth is not particularly limited as long as it can completely enclose the halocyclosilane salt synthesis vessel and the cyclohexasilane synthesis vessel, and its material, formation method, and oxygen concentration and moisture concentration in the explosion-proof booth. For such control means and the like, known techniques may be taken into consideration as appropriate. More preferably, together with the halocyclosilane salt synthesis vessel and the cyclohexasilane synthesis vessel, the concentrator, the tubes connecting the synthesis vessels, and the tubes connecting the concentrator and the synthesis vessel are also accommodated in the explosion-proof booth.

Hereinafter, the raw materials and each reaction condition used in the halocyclosilane salt synthesis step and the cyclohexasilane synthesis step of the present invention will be described.
(Halocyclosilane salt synthesis process)
In the halocyclosilane salt synthesis step, a halocyclosilane salt is synthesized by a cyclization coupling reaction of trihalosilane in the presence of a tertiary polyamine or a halogenated onium salt.
Examples of the trihalosilane include trichlorosilane, tribromosilane, triiodosilane, and trifluorosilane. Among these, trichlorosilane is preferable.
Examples of the tertiary polyamine include N, N, N ′, N ″, N ″ -pentaethyldiethylenetriamine (“peda”) and the like, such as an alkylene group (particularly an ethylene group). Examples thereof include polyalkyleneamines in which an alkylene group having 1 to 6 carbon atoms is preferable and an alkyl group (particularly an alkyl group having 1 to 6 carbon atoms such as an ethyl group is preferable). Here, the repeating unit of the alkylene amine is, for example, 2 or more, preferably about 2 to 6, and more preferably about 2 to 4.

Examples of the onium halide salt include tetraalkylphosphonium and tetraarylphosphonium represented by 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)). ), Ammoniums (such as tetraalkylammonium and tetraarylammonium represented by 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 chloro And salts with halogen anions such as anions, bromo anions and iodine anions.
The use amount (total use amount) of the tertiary polyamine or halogenated onium salt is preferably 0.01 mol or more and 0.5 mol or less, more preferably 0.05 mol or more and 0 mol, per 1 mol of trihalosilane. .4 mol or less, more preferably 0.1 mol or more and 0.3 mol or less. If the amount of phosphonium salt or ammonium salt is too small, unreacted trihalosilane will remain, which may reduce the yield of the halocyclosilane salt. On the other hand, if the amount is too large, the purity of the halocyclosilane salt will decrease. There is a fear.

  The cyclization coupling reaction is preferably performed in the presence of a basic compound. Examples of the basic compound include (mono-, di-, tri-, poly-) amine compounds. Among them, monoamine compounds are preferable. Specifically, for example, triethylamine, tripropylamine, tributylamine, trioctylamine, triisobutylamine, triisopentylamine, diethylmethylamine, diisopropylethylamine, dimethylbutylamine, dimethyl-2-ethylhexylamine, diisopropyl-2- Preferable examples include ethylhexylamine and methyldioctylamine.

  The amount of the basic compound used may be appropriately set according to the type and the like. For example, in the case of a monoamine compound, it is preferably 0.10 mol or more and 1.2 mol or less with respect to 1 mol of trihalosilane, More preferably, it is 0.20 mol or more and 1.0 mol or less, More preferably, it is 0.40 mol or more and 0.80 mol or less. If the basic compound (monoamine compound) is too small, unreacted trihalosilane may remain and the yield of the halocyclosilane salt may decrease. On the other hand, if the amount is too large, the yield of the halocyclosilane salt may decrease. There is a risk of causing a decrease in purity. In addition, although a diamine compound, a triamine compound, and a polyamine compound can also be used as a basic compound, the usage-amount (total usage-amount) of these basic compounds (di-, tri-, poly-amine) is trihalo. 0.5 mol or less is preferable with respect to 1 mol of silane, More preferably, it is 0.4 mol or less, More preferably, it is 0.3 mol or less.

  The cyclization coupling reaction can be carried out in an organic solvent as necessary. The organic solvent is preferably a solvent that does not interfere with the coupling reaction. For example, a halogenated hydrocarbon solvent (for example, chloroform, dichloromethane, 1,2-dichloroethane, etc.), an ether solvent (for example, diethyl ether, tetrahydrofuran, cyclopentylmethyl). Preferred are aprotic polar solvents such as ether, diisopropyl ether, methyl tertiary butyl ether), acetonitrile, N, N-dimethylformamide, and dimethyl sulfoxide. Among these, chlorinated hydrocarbon solvents such as chloroform, dichloromethane and 1,2-dichloroethane are preferable, and 1,2-dichloroethane is particularly preferable.

  The amount of the organic solvent used for the cyclization coupling reaction is not particularly limited, but it is usually preferable to adjust the concentration of the trihalosilane to be 0.5 mol / L or more and 10 mol / L or less, and more preferable concentration. Is 0.8 mol / L or more and 8 mol / L or less, and a more preferable concentration is 1 mol / L or more and 5 mol / L or less.

In the cyclization coupling reaction, the reaction temperature can be appropriately set according to the reactivity, and is, for example, about 0 to 120 ° C, preferably about 15 to 70 ° C. The reaction time may be appropriately determined according to the progress of the reaction, but is usually 30 minutes or longer and 72 hours or shorter, preferably 2 hours or longer and 48 hours or shorter, more preferably 6 hours or longer and 36 hours or shorter.
The cyclization coupling reaction is desirably performed under substantially anhydrous conditions, and is preferably performed, for example, in a dry gas (particularly inert gas such as nitrogen gas or argon gas) atmosphere.

Through the above cyclization coupling reaction, tetradecahalocyclohexasilane / halocyclosilane salt (halocyclosilane salt) is precipitated. Preferred examples of the halocyclosilane salt include tetradecachlorocyclohexasilane dianion salt.
The tetradecachlorocyclohexasilane dianion salt comprises tetradecachlorocyclohexasilane dianion ([Si ₆ Cl ₁₄ ^-2 ]) and a cation which is a counter ion of the anion, and is preferably represented by the following formula.
[X ^{n +} ] _{2 / n} [Si ₆ Cl ₁₄ ²⁻ ]
(In the formula, X ^{n +} represents a cation. N represents the valence of the cation, and is preferably 1.)

The X ^{n +} is not particularly limited as long as it can form a stable salt with the dianion. For example, the above-described tertiary polyamine and chlorosilane residue (for example, a silicon atom, a tertiary polyamine, a chlorine atom, and a hydrogen atom) And the above-mentioned oniums and the like.

(Cyclohexasilane synthesis process)
In the cyclohexasilane synthesis step, cyclohexasilane is synthesized by reducing the halocyclosilane salt with a reducing agent.
Although it does not restrict | limit especially as a reducing agent which can be used for a reductive reaction, It is preferable to use 1 or more types chosen from the group which consists of an aluminum-type reducing agent and a boron-type reducing agent. Examples of the aluminum-based reducing agent include metal hydrides such as lithium aluminum hydride, diisobutylaluminum hydride, and sodium bis (2-methoxyethoxy) aluminum hydride. Examples of the boron reducing agent include metal hydrides such as sodium borohydride and lithium triethylborohydride. In addition, only 1 type may be used for a reducing agent and it may use 2 or more types together.

  The amount of the reducing agent used may be appropriately set. For example, the molar equivalent of the reducing agent with respect to one silicon-halogen bond of the halocyclosilane salt may be at least 1 equivalent, preferably 2 equivalents or more. 50 equivalents or less, more preferably 5 equivalents or more and 40 equivalents or less, and still more preferably 10 equivalents or more and 30 equivalents or less. If the amount of the reducing agent used is too large, the post-treatment takes time and the productivity tends to decrease. On the other hand, if it is too small, the yield tends to decrease.

  The reduction reaction can be performed in the presence of an organic solvent, if necessary. Examples of the organic solvent that can be used here include 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 organic solvents may use only 1 type and may use 2 or more types together. The organic solvent used in the reduction step is preferably subjected to purification such as distillation or dehydration before the reaction in order to remove water and dissolved oxygen contained therein.

  The amount of the organic solvent used for the reduction reaction is preferably adjusted so that the concentration of the halocyclosilane salt is 0.01 mol / L or more and 1 mol / L or less, and a more preferable concentration is 0.02 mol / L or more. 0.7 mol / L or less, and a more preferable concentration is 0.03 mol / L or more and 0.5 mol / L or less. If the concentration of the halocyclosilane salt is higher than the above range, that is, if the amount of the organic solvent used is too small, the heat generated by the reduction reaction is not sufficiently removed, and the reaction product is difficult to dissolve. There is a possibility that problems such as lowering may occur. On the other hand, when the concentration of the halocyclosilane salt is lower than the above range, that is, when the amount of the organic solvent used is excessive, the amount of the solvent to be distilled off when separating the organic solvent and cyclohexasilane after the reduction reaction increases. Therefore, productivity tends to decrease.

In the reduction reaction, the reaction temperature may be appropriately set according to the kind of the halocyclosilane salt or the reducing agent, and is usually −20 ° C. to 150 ° C., preferably −10 ° C. or higher, more preferably 0 ° C. or higher. The temperature is preferably 100 ° C. or lower, more preferably 80 ° C. or lower, and still more preferably 70 ° C. or lower. The reaction time may be appropriately determined according to the progress of the reaction, but is usually 10 minutes or longer and 72 hours or shorter, preferably 1 hour or longer and 48 hours or shorter, more preferably 2 hours or longer and 36 hours or shorter.
The reduction reaction is usually preferably performed in an atmosphere of an inert gas such as nitrogen gas or argon gas.

  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]
In an explosion-proof booth controlled to a nitrogen atmosphere with an oxygen concentration of 10% by volume or less and a moisture value of 10 ppm or less, a 3L synthesis container 1 and a 3L synthesis container 2 having a mesh member 8 (mesh pore diameter is 20 μm) inside The production line shown in FIG. 1 comprising the concentrator 5 is assembled, and the nitrogen gas is introduced into the reaction system so that each container and the inside of the tube have a nitrogen atmosphere with an oxygen concentration of 10 vol% or less and a moisture value of 10 ppm or less. It was circulated at a flow rate of 1.0 L / min.
First, 59.1 g (0.24 mol) of N, N, N ′, N ″, N ″ -pentaethyldiethylenetriamine (pedeta), diisopropyl, in a synthesis vessel 1 for synthesizing a halocyclohexasilane salt. 94.2 g (0.73 mol) of ethylamine and 313.4 g (3.17 mol) of 1,2-dichloroethane were charged, respectively. Next, 164.5 g (1.21 mol) of trichlorosilane and 657.9 g of 1,2-dichloroethane (6. 6) were obtained while controlling the liquid temperature in the synthesis container 1 at 20 ° C. and stirring the inside of the container 1 with a stirring blade. 65 mol) was added dropwise at a rate of 7.0 g / min. After completion of the dropwise addition, a heating medium is circulated through the jacket, and the contents in the container 1 are aged for 24 hours while being heated to 50 ° C. to form a halocyclosilane salt in the reaction solution. It was.
Next, by pressurizing the inside of the synthesis container 1 with nitrogen gas, the content in the synthesis container 1 (a solution containing a solid of a halocyclosilane salt) is transferred to the cyclohexasilane synthesis container 2 through the tube 3 and the synthesis is performed. The solid of the halocyclosilane salt was collected by filtration with the mesh member 8 of the container 2. Subsequently, the filtered solid on the mesh member 8 is washed with an appropriate amount of cyclopentyl methyl ether to remove a residual liquid such as 1,2-dichloroethane, and a halocyclosilane salt [peda · SiH ₂ Cl ⁺ ] ₂ [Si ₆ Cl ₁₄ < ^2- > white solid 95.0g (0.074mol) was obtained.

  Next, 1951.8 g (19.5 mol) of cyclopentyl methyl ether was added to the synthesis container 2 to prepare a slurry solution of a halocyclosilane salt. Next, the liquid temperature in the synthesis container 2 is controlled to 20 ° C., nitrogen gas is circulated at a flow rate of 2.7 L / min, and the synthesis container 2 is stirred with a stirring blade at a speed of 150 rpm. A slurry solution consisting of 14.6 g (0.38 mol) of lithium aluminum hydride and 548.2 g (5.47 mol) of cyclopentyl methyl ether was added dropwise at a rate of 3.0 g / min to cause a reduction reaction. The monosilane gas generated during the reduction reaction was detoxified by providing an alkaline gas trap of an aqueous potassium hydroxide solution at the nitrogen gas outlet. After completion of the dropping, stirring was continued for 24 hours to confirm that no monosilane gas was generated, and the reaction was completed. After completion of the reaction, the inside of the synthesis vessel 2 is pressurized with nitrogen gas to filter out unnecessary metal salts and the like by-produced on the mesh member 8, and the reaction solution containing cyclohexasilane is passed through the tube 4 to the concentrator 5. Transferred. Then, the reaction solution transferred to the concentrator 5 was concentrated under reduced pressure to remove cyclopentyl methyl ether from the reaction solvent outlet 6 to obtain 9.50 g (0.053 mol) of cyclohexasilane as a colorless transparent liquid.

DESCRIPTION OF SYMBOLS 1 Halocyclosilane salt synthesis container 2 Cyclohexasilane synthesis container 3, 4 Tube 5 Concentrator 6 Reaction solvent evaporating port 7 Cyclohexasilane take-out port 8 Mesh member 9 Valve 10 Outlet 11 Outer cylinder 12 Inner cylinder 13 Fixing member 14 Raw material supply port 15 Shaft 16 Stirring blade 17 Jacket 18 Thermometer 19 Gas supply pipe 20 Pressure gauge

Claims (7)

Cyclocoupling of trihalosilane was used to synthesize a tetradecahalocyclohexasilane / dianion-containing compound. The dianion-containing compound was filtered from the synthesis solution, and the filtered dianion-containing compound was reduced to obtain cyclohexasilane. A method of producing cyclohexasilane by synthesizing and filtering off insoluble matter contained in the cyclohexasilane synthesis solution,
Both the filtration of the dianion-containing compound and the insoluble matter from the cyclohexasilane synthesis solution are performed by a mesh member attached in the cyclohexasilane synthesis vessel or downstream from the discharge port of the synthesis vessel. A process for producing cyclohexasilane.   The method for producing cyclohexasilane according to claim 1, wherein the mesh member is attached in a cyclohexasilane synthesis container.   The method for producing cyclohexasilane according to claim 2, wherein the cyclohexasilane synthesis container has an inner / outer cylinder double structure, and the mesh member is formed in the inner cylinder.   The method for producing cyclohexasilane according to claim 1, wherein the mesh member has a mesh pore diameter of 3 to 100 μm.   The method for producing cyclohexasilane according to any one of claims 1 to 4, wherein the dianion-containing compound synthesis vessel and the cyclohexasilane synthesis vessel are the same or different.   The method for producing cyclohexasilane according to any one of claims 1 to 5, wherein the dianion-containing compound synthesis vessel and the cyclohexasilane synthesis vessel are accommodated in one explosion-proof booth.   The method for producing cyclohexasilane according to claim 6, wherein the inside of the explosion-proof booth is controlled to an inert gas atmosphere having an oxygen concentration of 10% by volume or less and a water concentration of 10 ppm (volume basis) or less.

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