JP7621162B2 - Method for producing cyclic silane hydride compounds - Google Patents

Description

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

Attempts are being made to use cyclic hydrogenated silanes such as cyclopentasilane and cyclohexasilane instead of conventional monosilane as a raw material for thin-film silicon used in solar cells, semiconductors, etc.

As a method for producing a cyclic silane hydride, for example, Non-Patent Document 1 describes the following: a diethyl ether solution of _LiAlH4 is added to a diethyl ether solution of a salt of a _{cyclic halosilane} compound, [( _Et2NCH2CH2 ) _{2NEt.H2SiCl ]2 [ Si6Cl14 ]} , to carry out a reduction reaction; solids are removed from the reaction mixture by filtration; the mixture is washed with diethyl ether, and the filtrate is concentrated under vacuum; the crude product is extracted with pentane; the pentane extract is washed by adding 9N sulfuric acid _; the organic layer is dried over _Na2SO4 ; filtered; and then distilled under reduced pressure to produce cyclohexasilane.

Xiaotang Lu et al. , “Low Temperature Colloidal Synthesis of Silicon Nanorods from Isotetrasilane, Neopentasilane, and Cyclohexasilane”, Chem. Mater. , 27, p6053 (2015)

As described above, several methods for producing cyclic silane hydride compounds are known. However, the inventors have found that when the solid content is filtered from the reaction solution after reducing the salt of the cyclic halosilane compound, as in the method known in Non-Patent Document 1, components derived from the reducing agent adhere to the transport route when the reaction solution containing the solid content is transported. The inventors have also found that if the adhered matter accumulates, it may ignite. Furthermore, in order to treat the solid content after filtration, it is necessary to remove the solid that has a risk of ignition from the filter, and it is necessary to disperse it in a solvent or the like and recover it, and it has been found that the problem of adhesion occurs in the filter and the transport route in this case.
Therefore, an object of the present disclosure is to provide a method for producing a cyclic silane hydride by reducing a cyclic halosilane compound, which prevents components derived from the reducing agent from adhering to the production equipment and efficiently produces a cyclic silane hydride.

The present inventors have conducted various investigations to achieve the above object and have arrived at the present invention.
That is, the present disclosure relates to a method for producing a cyclic silane hydrogen compound, the method comprising: a step (A) of contacting one or more compounds selected from a cyclic halosilane compound, a salt of a cyclic halosilane compound, and a complex of a cyclic halosilane compound with a reducing agent; and a step (B) of contacting the reduction reaction liquid obtained in the step (A) with an acidic aqueous solution.

The manufacturing method disclosed herein can prevent components derived from the reducing agent from adhering to the manufacturing equipment, making it possible to safely and efficiently manufacture cyclic hydrogen silanes.

The present disclosure will be described in detail below.
In addition, a combination of two or more of the individual preferred embodiments of the present disclosure described below is also a preferred embodiment of the present disclosure.

[Cyclic silane hydride compounds of the present disclosure]
In the present disclosure, the cyclic silane hydrogenation may be any compound having a ring structure containing one or more Si atoms and one or more Si-H bonds, and the ring structure may have a substituent (hereinafter, also referred to as the cyclic silane hydrogenation compound of the present disclosure). In the cyclic silane hydrogenation compound of the present disclosure, the number of Si atoms in one molecule is preferably 3 or more, more preferably 5 or more, and preferably 14 or less, and more preferably 7 or less. The cyclic silane hydrogenation compound of the present disclosure preferably contains a silicon monocycle.
The cyclic silane hydrogen compound of the present disclosure can be represented, for example, by the following general formula (1).

In the above general formula (1), ^X1 and ^X2 each independently represent a halogen atom, n represents a number from 0 to 5, b represents a number from 1 to 2n, a and c each represent a number from 0 to 2n-1 (where a+b+c=2n), and d and e each represent a number from 0 to 3 (where d+e is 3).

In the above general formula (1), a is the number of halogen atoms directly bonded to the Si atom contained in the ring structure, b is the number of hydrogen atoms directly bonded to the Si atom contained in the ring structure, and c is the number of -SiX ² _d H _e groups directly bonded to the Si atom contained in the ring structure. For example, when n is 3, the ring structure contained in the cyclic hydrogen silane compound of the present disclosure is a 6-membered ring structure containing 6 Si atoms. d is the number of halogen atoms bonded to the Si atom in each -SiX ² _d H _e group, and e is the number of hydrogen atoms bonded to the Si atom in each -SiX ² _d H _e group.

In the above general formula (1), n is preferably 2 or more and preferably 4 or less. In the above general formula (1), b is preferably 10 or more and preferably 14 or less. In the above general formula (1), c is preferably 1 or less and more preferably 0. In the above general formula (1), e is more preferably 3.

In the above general formula (1), the halogen atoms of ^X1 and ^X2 include a chlorine atom, a bromine atom, an iodine atom, and a fluorine atom, preferably a chlorine atom or a bromine atom, and more preferably a chlorine atom. When there are a plurality of ^X1 and/or ^X2 , they may be the same or different.

Preferred examples of the cyclic silane hydride compound of the present disclosure include cyclopentasilane, silylcyclopentasilane, cyclohexasilane, silylcyclohexasilane, cycloheptasilane _, silylcycloheptasilane _{, Si5H9-Si5H9, Si6H11-Si6H11, Si7H13-Si7H13 , and the like , with cyclopentasilane or cyclohexasilane being} more preferred.

[Cyclic halosilane compounds of the present disclosure]
<Cyclic halosilane compound>
In the present disclosure, a cyclic halosilane compound may be any compound having a ring structure containing one or more Si atoms and one or more Si-halogen bond, and the ring structure may have a substituent (hereinafter, also referred to as the cyclic halosilane compound of the present disclosure). In the cyclic halosilane compound of the present disclosure, the number of Si atoms in one molecule is preferably 3 or more, more preferably 5 or more, and preferably 14 or less, and more preferably 7 or less. The cyclic halosilane compound of the present disclosure preferably contains a silicon monocycle.

The cyclic halosilane compound of the present disclosure can be represented, for example, by the following general formula (2):

In the above general formula (2), ^X1 and ^X2 each independently represent a halogen atom, n represents a number from 0 to 5, a represents a number from 1 to 2n, b and c each represent a number from 0 to 2n-1 (where a+b+c=2n), and d and e each represent a number from 0 to 3 (where d+e is 3).

In the above general formula (2), a is the number of halogen atoms directly bonded to the Si atom contained in the ring structure, b is the number of hydrogen atoms directly bonded to the Si atom contained in the ring structure, and c is the number of -SiX ² _d H _e groups directly bonded to the Si atom contained in the ring structure. For example, when n is 3, the ring structure contained in the cyclic halosilane compound of the present disclosure is a 6-membered ring structure containing 6 Si atoms. d is the number of halogen atoms bonded to the Si atom in each -SiX ² _d H _e group, and e is the number of hydrogen atoms bonded to the Si atom in each -SiX ² _d H _e group.

In the above general formula (2), n is preferably 2 or more and preferably 4 or less. In the above general formula (2), a is preferably 10 or more and preferably 14 or less. In the above general formula (2), c is preferably 1 or less and more preferably 0. In the above general formula (2), d is more preferably 3.

In the above general formula (2), the halogen atoms of ^X1 and ^X2 include a chlorine atom, a bromine atom, an iodine atom, and a fluorine atom, preferably a chlorine atom or a bromine atom, and more preferably a chlorine atom. When there are a plurality of ^X1 and/or ^X2 , they may be the same or different.

Preferred examples of the cyclic halosilane compounds of the present disclosure include decachlorocyclopentasilane, trichlorosilyl-nonachlorocyclopentasilane, dodecachlorocyclohexasilane, trichlorosilyl _- undecachlorocyclohexasilane _, tetradecacycloheptasilane, trichlorosilyl-tridecachlorocycloheptasilane, _{Si5Cl9 - Si5Cl9 ,} Si6Cl11 _{-Si6Cl11 , Si7Cl13 - Si7Cl13} , and the like, with decachlorocyclopentasilane or _{dodecachlorocyclohexasilane} being more preferred.

The cyclic halosilane compound of the present disclosure can be produced, for example, by the method described in step (E) below, without any particular limitation.

<Salt of Cyclic Halosilane Compound>
In the present disclosure, the salt of a cyclic halosilane compound may have a ring structure containing one or more Si atoms, an anion moiety containing one or more Si-halogen bond, and a counter cation moiety, and the ring structure may have a substituent (hereinafter, also referred to as the salt of a cyclic halosilane compound of the present disclosure). The number of Si atoms in one molecule of the salt of a cyclic halosilane compound of the present disclosure is preferably 3 or more, more preferably 5 or more, and preferably 14 or less, and more preferably 7 or less. The salt of a cyclic halosilane compound of the present disclosure preferably contains a silicon monocycle.

The salt of the cyclic halosilane compound may contain any structure as a counter cation moiety. Examples of the counter cation moiety include oniums (e.g., phosphonium ion and ammonium ion); polyamines.SiH _{2 Cl + such as N,N,N',N",N"-pentaethyldiethylenetriamine (pedeta).SiH 2} ^Cl _{+ and N,N,N',N'-tetraethylethylenediamine (teda).SiH 2} ^Cl ₊ ^.

The salt of the cyclic halosilane compound is preferably a phosphonium salt or an ammonium salt. The salt of the cyclic halosilane compound preferably contains a structure represented by the following general formula (3) or (4) as the counter cation site.

In formula (3) or (4), R ¹ to R ⁴ each independently represent a hydrogen atom, an alkyl group which may have a substituent, or an aryl group which may have a substituent. In formula (3) or (4), R ¹ to R ⁴ may be different from each other, but it is preferable that they are all the same group. As the alkyl group, preferred examples include alkyl groups having 1 to 16 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, and cyclohexyl, and more preferably alkyl groups having 1 to 8 carbon atoms. As the aryl group, preferred examples include aryl groups having 6 to 18 carbon atoms, such as phenyl and naphthyl, and more preferably aryl groups having 6 to 12 carbon atoms. As the substituent, there is no particular limitation, and examples include halogen atoms, alkyl groups, aryl groups, alkoxy groups, and hydroxyl groups.
In addition, R ¹ to R ⁴ are preferably alkyl groups or aryl groups, as this tends to facilitate the production of high-purity salts of the cyclic halosilane compound, and in particular, in the case of formula (3), aryl groups are more preferable, and in the case of formula (4), alkyl groups are more preferable. As the counter cation, ammonium ions are more preferable than phosphonium ions.

The salt of the cyclic halosilane compound of the present disclosure can be represented, for example, by the following general formula (5):

In the above general formula (5), ^X1 and ^X2 each independently represent a halogen atom, n represents a number from 0 to 5, a represents a number from 1 to 2n, b and c each represent a number from 0 to 2n-1 (provided that a+b+c=2n), d and e each represent a number from 0 to 3 (provided that d+e is 3), L represents an anionic ligand, p represents an integer from -2 to 0 as the valence of the ligand L, K represents a counter cation, q represents an integer from 0 to 2 as the valence of the counter cation K, 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 general formula (5), a is the number of halogen atoms directly bonded to the Si atom contained in the ring structure, b is the number of hydrogen atoms directly bonded to the Si atom contained in the ring structure, and c is the number of -SiX ² _d H _e groups directly bonded to the Si atom contained in the ring structure. For example, when n is 3, the ring structure contained in the cyclic halosilane compound of the present disclosure is a 6-membered ring structure containing 6 Si atoms. d is the number of halogen atoms bonded to the Si atom in each -SiX ² _d H _e group, and e is the number of hydrogen atoms bonded to the Si atom in each -SiX ² _d H _e group.

In the above general formula (5), n is preferably 2 or more and preferably 4 or less. In the above general formula (5), a is preferably 10 or more and preferably 14 or less. In the above general formula (5), c is preferably 1 or less and more preferably 0. In the above general formula (5), d is more preferably 3.

In the above general formula (3), the halogen atoms of ^X1 and ^X2 include a chlorine atom, a bromine atom, an iodine atom, and a fluorine atom, preferably a chlorine atom or a bromine atom, and more preferably a chlorine atom. When there are a plurality of ^X1 and/or ^X2 , they may be the same or different.
In formula (5), L represents an anionic ligand coordinated to a silicon atom constituting the ring, p represents the valence of the ligand (an integer of −2 to 0), and m represents the number of ligands (1 to 2). Examples of the anionic ligand include a halide ion, a nitrate ion, and a cyanide ion.
In formula (5), K represents a counter cation, q represents the valence of the counter cation K (an integer of 0 to 2), and the values of s and t are determined depending on the valence and number of the ligand L and the valence of the counter cation K. The preferred form of the counter cation is as described above.
Specific examples of salts of the cyclic halosilane compounds of the present disclosure include _salts of tetradecachlorocyclohexasilane dianion complex ([ _Si6Cl142- ]), salts of tetradecabromocyclohexasilane dianion complex ( ^[ _Si6Br142- ^] ), [ _Si5Cl122- ^] _, [ _Si5Br122- ], etc. The counter ion is preferably _a phosphonium ion or an _ammonium ^ion .
Examples of salts of the cyclic halosilane compounds of the present disclosure include compounds represented by the following general formulas (6) and (7).

In the above general formulas (6) and (7), ^X1 , ^X2 , a, b, c, d, e, and their preferred forms are the same as those in the above general formula (5), and ^R1 , ^R2 , ^R3 , ^R4, and their preferred forms are the same as those in the above general formulas (3) and (4). In the above general formulas (6) and (7), ^X3 represents a halogen atom. In formulas (6) and (7), ^X3 exists in the form of an ion and is a halide ion.

The salt of the cyclic halosilane compound of the present disclosure is not particularly limited, but can be produced, for example, by the method described in step (D) below.
<Complex of Cyclic Halosilane Compound>
In the present disclosure, a complex of a cyclic halosilane compound includes a ring structure containing one or more Si elements and one or more Si-halogen bond, and may include at least one coordination compound, and the ring structure may have a substituent (hereinafter, also referred to as a complex of a cyclic halosilane compound of the present disclosure). In a complex of a cyclic halosilane compound of the present disclosure, the number of Si elements in one molecule is preferably 3 or more, more preferably 5 or more, and preferably 14 or less, and more preferably 7 or less. A complex of a cyclic halosilane compound of the present disclosure preferably includes a silicon monocycle.

The complex of the cyclic halosilane compound of the present disclosure is preferably a cyclic halosilane neutral complex containing at least one coordination compound selected from the group consisting of the following (i) and (ii):
(i) A compound represented by XR _h (when X is P, P═O or N, h=3; R is the same or different and represents a substituted or unsubstituted alkyl group or aryl group; when X is S, S═O or O, h=2; R is the same or different and represents the same group as above; however, the number of amino groups in XR _h is 0 or 1),
(ii) Substituted or unsubstituted heterocyclic compounds containing N, O, S or P having an unshared electron pair in the ring.

A preferred example of the complex of the cyclic halosilane compound of the present disclosure is a cyclic halosilane neutral complex represented by the following general formula (8):

In the above general formula (8), X ¹ , X ² , a, b, c, d, e and their preferred forms are the same as those in the above general formula (5), and Y is at least one coordination compound selected from the group consisting of (i) a compound represented by XR _h (when X is P, P═O, N, h=3, R is the same or different and represents a substituted or unsubstituted alkyl group or aryl group, and when X is S, S═O, O, h=2, R is the same or different and represents the same group as above, with the proviso that the number of amino groups in XR _h is 0 or 1), and (ii) a substituted or unsubstituted heterocyclic compound containing N, O, S or P having an unshared electron pair in the ring), and l is 1 or 2.
Specific examples of the compound (i) include compounds where X is P, P=O, or N, such as _{triphenylphosphine} ( _PPh3 ), triphenylphosphine oxide (Ph3P=O), tris(4-methoxyphenyl)phosphine (P(MeOPh) ₃ ), and triphenylamine; and compounds where X is S=O, such as dimethyl sulfoxide.
(ii) In the heterocyclic compound, it is necessary that the ring has an unshared electron pair, and this unshared electron pair is coordinated to the cyclic silane to form a cyclic halosilane neutral complex. Such heterocyclic compounds include one or more substituted or unsubstituted heterocyclic compounds containing N, O, S, or P having an unshared electron pair in the ring. The substituents that the heterocyclic compound may have are the same as the substituents that may be possessed when R is an alkyl group or an aryl group when X is P or P=O. Examples of the heterocyclic compound include pyridines, imidazoles, pyrazoles, oxazoles, thiazoles, imidazolines, pyrazines, thiophenes, furans, etc., and specific examples include N,N-dimethyl-4-aminopyridine, tetrahydrothiophene, tetrahydrofuran, etc.

Preferred examples of complexes of _{the cyclic halosilane compounds of the present disclosure include [PPh3]2[Si6Cl12 ] , [ Ph3P} =O] ₂ [ _Si6Cl12 ], [ _P ( _CH3OPh ) ₃ ] _{2 [ Si6Cl12} ], and [N,N-dimethyl-4-aminopyridine] ₂ [ _{Si6Cl12 ]} .

The complex of the cyclic halosilane compound of the present disclosure is not particularly limited, but can be produced, for example, by the method described in step (F) below.

[Method for producing cyclic silane hydride compounds according to the present disclosure]
<Step (A)>
The method for producing a cyclic silane hydrogen compound of the present disclosure includes a step of contacting one or more compounds selected from a cyclic halosilane compound, a salt of a cyclic halosilane compound, and a complex of a cyclic halosilane compound (hereinafter also referred to as "cyclic halosilane compound, etc.") with a reducing agent (hereinafter also referred to as "step (A)"). One or more of the cyclic halosilane compounds, etc. can be used.

The reducing agent used in step (A) is not particularly limited, but examples thereof include neutral or ionic hydride compounds, and is preferably at least one selected from aluminum hydride compounds, boron hydride compounds, silicon hydride compounds, tin hydride compounds, and transition metal hydride compounds. Specific examples of aluminum hydride compounds include lithium aluminum hydride, diisobutylaluminum hydride, and sodium bis(2-methoxyethoxy)aluminum hydride. Specific examples of boron hydride compounds include sodium borohydride, lithium triethylborohydride, nickel borohydride, and zinc borohydride. Specific examples of silicon hydride compounds include triethylsilane and triisopropylsilane. Specific examples of tin hydride compounds include tributyltin hydride.

The amount of reducing agent used in step (A) may be appropriately set. For example, the amount of hydride in the hydride compound per silicon-halogen bond in the cyclic halosilane compound or the like is preferably 0.5 equivalents or more, more preferably 0.8 equivalents or more, even more preferably 0.9 equivalents or more, and preferably 15 equivalents or less, more preferably 5 equivalents or less, and even more preferably 2 equivalents or less.

In step (A), an organic solvent may be used. Examples of solvents that can be used in step (A) include hydrocarbon solvents such as hexane, heptane, and toluene; ether solvents such as diethyl ether, tetrahydrofuran, cyclopentyl methyl ether, diisopropyl ether, dibutyl ether, and methyl tertiary butyl ether; and halogenated carbon solvents such as dichloromethane and dichloroethane. Step (A) is preferably carried out in the presence of at least one selected from hydrocarbon solvents and ether solvents. Step (A) may be carried out in the presence of one or more solvents. In this disclosure, the solvent may be any solvent that dissolves one or more of the reaction raw materials and/or one or more of the reaction products.

The amount of solvent used in step (A) is preferably 0.01 mol or more, more preferably 0.05 mol or more, and even more preferably 0.10 mol or more, and is preferably 5.0 mol or less, more preferably 3.0 mol or less, and even more preferably 1.0 mol or less, per 1 L of solvent. When the reaction is carried out using a solvent in the above range, the efficiency of the reduction reaction tends to improve.

In step (A), the total concentration of the cyclic halosilane compound and the cyclic hydrogen silane compound in the reaction solution is preferably 0.01 mol/L or more, more preferably 0.05 mol/L or more, and even more preferably 0.10 mol/L or more, and is preferably 5.0 mol/L or less, more preferably 3.0 mol/L or less, and even more preferably 1.0 mol/L or less. When the reaction is carried out within the above range, the efficiency of the reduction reaction tends to be improved.

The reaction temperature in step (A) may be adjusted appropriately depending on the reactivity, and is, for example, preferably -60°C or higher, more preferably -40°C or higher, even more preferably -20°C or higher, and preferably 150°C or lower, more preferably 100°C or lower, even more preferably 80°C or lower, and particularly preferably 70°C or lower. The reaction time may be adjusted appropriately depending on the extent of the progress of the reaction, and is, for example, preferably 10 minutes or more, more preferably 1 hour or more, even more preferably 2 hours or more, and preferably 72 hours or lower, more preferably 48 hours or lower, and even more preferably 24 hours or lower.

Step (A) is preferably carried out under an inert gas atmosphere such as nitrogen gas or argon gas.

In step (A), the cyclic halosilane compound, etc., and the reducing agent are preferably brought into contact in the presence of a solvent. Examples of methods for bringing the cyclic halosilane compound, etc., and the reducing agent into contact in the presence of a solvent include (1) a method in which one of the cyclic halosilane compound, etc. and the reducing agent is dissolved or dispersed in a solvent to form a solution or dispersion, and then mixed with the other (the other is added to the solution or dispersion, or the solution or dispersion is added to the other), (2) a method in which both are dissolved or dispersed in a solvent to form a solution or dispersion, and then the two are mixed, and (3) a method in which the cyclic halosilane compound, etc. and the reducing agent are added to the solvent simultaneously or sequentially. Among these, the above-mentioned mode (2) is particularly preferred.

In step (A), the cyclic halosilane compound or the like or the reducing agent may be added to the reaction system in one lump, or preferably in a sequential manner. The sequential addition may be in portions, or preferably in a continuous manner.
Step (A) may be a batch reaction, or a continuous reaction using a continuous bed reactor such as a CSTR, or a tubular reactor such as a microreactor or a flow reactor.

<Step (B)>
The method for producing a cyclic silane hydride compound of the present disclosure includes a step of contacting the reduction reaction solution obtained in the step (A) with an acidic aqueous solution (hereinafter also referred to as "step (B)").

It is preferable that step (B) is carried out without a solid-liquid separation step after step (A). In the above case, the adhesion of components derived from the reducing agent to the manufacturing equipment tends to be further suppressed. In this disclosure, "contacting the reduction reaction liquid obtained in step (A) with an acidic aqueous solution" means that the reduction reaction liquid obtained in step (A) is contacted with an acidic aqueous solution without substantially passing through a solid-liquid separation step. "Substantially not passing through a solid-liquid separation step" means, for example, that 10% by mass or more, preferably 5% by mass or more of the solid content is not separated from the reduction reaction liquid obtained in step (A). It is more preferable that step (B) is carried out subsequent to step (A).

In step (B), it is more preferable to contact the reduction reaction solution with the acidic aqueous solution without going through a concentration step. Although the solvent may be removed by distillation before contacting with the acidic aqueous solution, excessive concentration may cause the deposition of solids on the top of the concentration vessel or in the cooler, and therefore it is preferable to concentrate the solution to a solid content of 30% or less.
When both steps (A) and (B) are carried out as batch reactions, it is preferable to carry out steps (A) and (B) in the same reactor (reaction kettle). When either or both of steps (A) and (B) are carried out as continuous reactions, it is preferable to carry out them in a microreactor or a flow reactor.

In step (B), the concentration of the acidic substance in the acidic aqueous solution brought into contact with the reduction reaction solution obtained in step (A) is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 1% by mass or more, preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less. In the above case, there is a tendency for the adhesion of components derived from the reducing agent to the manufacturing equipment to be further suppressed.

The amount of the acidic aqueous solution used is preferably 1 to 10,000 parts by mass, more preferably 10 to 5,000 parts by mass, and even more preferably 20 to 3,000 parts by mass, per 100 parts by mass of the reduction reaction solution.

The acidic substance is not particularly limited, and examples include organic acids and inorganic acids, but it is preferable that the acidic substance contains at least one selected from hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid.

In the step (B), when the reduction reaction solution is brought into contact with the acidic aqueous solution, it is preferable to sequentially add at least one of the reduction reaction solution and the acidic aqueous solution to the reactor. By dropping one or both of the reduction reaction solution and the acidic aqueous solution in this manner, the formation of solid residues is suppressed while the residue of the reducing agent contained in the reduction reaction solution tends to be decomposed, and the generated heat and the generated acidic gas and hydrogen gas can also be controlled by the addition rate, which leads to an effect of improving productivity.
In the step (B), preferred embodiments for dropping one or both of the reduction reaction solution and the acidic aqueous solution are (1) an embodiment in which the reduction reaction solution is charged in a reactor and the acidic aqueous solution is added thereto, (2) an embodiment in which the acidic aqueous solution is charged in a reactor and the reduction reaction solution is added thereto, and (3) an embodiment in which the reduction reaction solution and the acidic aqueous solution are added simultaneously or sequentially to the reactor. Among these, the embodiment (2), i.e., adding the reduction reaction solution to the acidic aqueous solution, is preferred.
The acidic aqueous solution used in step (B) is preferably degassed in advance to remove dissolved oxygen. Degassing may be performed by bubbling an inert gas such as nitrogen or argon into the acidic aqueous solution, by repeatedly reducing the pressure and replacing the solution with an inert gas such as nitrogen or argon several times, by boiling the solution under normal or reduced pressure, by irradiating the solution with ultrasonic waves, or by a combination of two or more of these methods.

The reactor used in step (B) is preferably equipped with a stirring means. The stirring means may be a dynamic stirring means such as a stirring blade, or a static stirring means such as a static mixer.

In step (B), the reaction temperature may be adjusted as appropriate, but is preferably -80°C or higher, more preferably -50°C or higher, even more preferably -30°C or higher, and is preferably 200°C or lower, more preferably 150°C or lower, and even more preferably 100°C or lower.

In step (B), the mixture of the reduction reaction solution and the acidic aqueous solution may be separated into an aqueous phase and an organic phase (also called an oil layer), and the organic phase may be separated to separate the solution containing the cyclic silane hydride compound. In order to completely remove the solids, the separated organic layer may be contacted with an aqueous acid solution or water, and then separated again into an aqueous layer and an organic layer.
The separated organic phase may be further subjected to a dehydration treatment. The dehydration treatment may be performed using a chemical desiccant such as an inorganic salt, such as sodium sulfate or magnesium sulfate, or a physical desiccant such as an alumina silicate (zeolite), such as molecular sieves.

The reduction reaction liquid obtained in step (A) preferably contains a cyclic hydrogen silane compound and an aluminum complex, and more preferably the aluminum complex is a complex of aluminum or an aluminum halide and an ether-based solvent. In the case of the above combination, adhesion of solids tends to be further suppressed.

<Step (C)>
The method for producing the cyclic silane hydride compound of the present disclosure is optional, but preferably includes a step of distilling the cyclic silane hydride compound (hereinafter also referred to as "step (C)").

The distillation method is not particularly limited, but examples thereof include simple distillation, precision distillation, molecular distillation, thin film evaporation, flash distillation, and combinations thereof.
The distillation may be carried out under reduced pressure, for example, preferably from 5 to 400 Pa, more preferably from 10 to 350 Pa, and further preferably from 10 to 300 Pa. The temperature condition is preferably from 20 to 80° C., and more preferably from 30 to 65° C.
The distillation step may be carried out two or more times.
The distillation process may be a batch distillation or a continuous distillation.
The method for producing the cyclic silane hydride compound of the present disclosure may optionally include a purification step other than the distillation step, such as a crystallization step.

<Step (D)>
The method for producing a cyclic silane hydride compound according to the present disclosure may optionally include a step of contacting a halogenated monosilane compound with at least one selected from a phosphonium salt and an ammonium salt (hereinafter also referred to as "step (D)"). When a salt of a cyclic halosilane compound produced by step (D) is used, the efficiency of step (A) and step (E) described below tends to be improved.

In step (D), a cyclization coupling reaction of the halosilane compound occurs by contacting the halosilane compound with at least one of a phosphonium salt and an ammonium salt, and a salt of a cyclic halosilane compound containing a ring formed by linking silicon atoms of the halosilane compound can be obtained. In this case, the salt of the cyclic halosilane compound obtained has a phosphonium ion or ammonium ion as a counter cation (i.e., a phosphonium salt or an ammonium salt), and since the counter cation does not contain a silicon atom, this is advantageous in that it is possible to suppress the generation of silane gas derived from the counter cation in a later step.

As the halosilane compound used in step (D), it is possible to use halogenated disilanes such as hexachlorodisilane, hexabromodisilane, and hexaiododisilane, but it is preferable to use monosilane compounds (halogenated monosilane compounds). For example, trihalogenated silanes such as trichlorosilane, tribromosilane, triiodosilane, and trifluorosilane; dihalogenated silanes such as dichlorosilane, dibromosilane, diiodosilane, and difluorosilane; tetrahalogenated silanes such as tetrachlorosilane, tetrabromosilane, tetraiodosilane, and tetrafluorosilane; etc., among which trihalogenated silanes are preferred, and trichlorosilane is more preferred.

The phosphonium salt used in step (D) is preferably a quaternary phosphonium salt, and preferred examples thereof include salts represented by the following formula (9). The ammonium salt is preferably a quaternary ammonium salt, and preferred examples thereof include salts represented by the following formula (10). In formulas (9) and (10), the aspects and preferred aspects of R ¹ to R ⁴ have the same meanings as in formulas (3) and (4) unless otherwise specified, and A ⁻ represents a monovalent anion.

In formula (9) and formula (10), examples of the monovalent anion represented by ^A- include halide ions (e.g., Cl- ^{, Br-} , I- ^, etc.), borate ions (e.g., _BF4- ), phosphorus anions (e.g., ^{PF6- )} , etc. Among these, from the viewpoint of ease of availability, ^Cl- , ^Br- , and ^I- are _preferred , and ^Cl- and ^Br- are particularly preferred.

In step (D), either the phosphonium salt or the ammonium salt may be used alone, or both may be used. The phosphonium salt may be used alone, or two or more may be used in combination. The ammonium salt may be used alone, or two or more may be used in combination. In step (D), a coupling agent other than the phosphonium salt and the ammonium salt may be used in combination. Examples of the other coupling agent include tertiary polyamines such as N,N,N',N",N"-pentaethyldiethylenetriamine (pedeta) and N,N,N',N'-tetraethylethylenediamine (teeda), and onium salts other than phosphonium salts and ammonium salts. In this case, the handleability of the resulting salt of the cyclic halosilane compound tends to be improved, so for example, it is preferable to use the other coupling agent in an amount of 0 to 10 mol% based on the total amount of the phosphonium salt and the ammonium salt.

By using the phosphonium salt represented by formula (9) or the ammonium salt represented by formula (10), it is possible to obtain a salt of a cyclic halosilane compound, and in particular, it is possible to easily obtain a salt of a cyclic halosilane compound that contains a six-membered silicon homocycle and does not contain any silicon atoms other than the silicon atoms that form this homocycle. For example, when trichlorosilane is used as the halosilane compound and a compound in which R ¹ to R ⁴ in formula ( ⁹ ) are phenyl groups and A ^- is a chloride ion (Cl ^- ) is used as the phosphonium salt, salts consisting of the dianion of a cyclic halosilane compound and a phosphonium ion, such as dodecachlorodihydrocyclohexasilane dianion salt ([Ph ₄ P ⁺ ] ₂ [Si ₆ H ₂ Cl ₁₂ ^2- ]), tridecachlorohydrocyclohexasilane dianion salt ([Ph ₄ P + ] ₂ [Si ₆ HCl ₁₃ ^2- ]), or tetradecachlorocyclohexasilane dianion salt ([Ph ₄ P ⁺ ] ₂ [Si ₆ Cl ₁₄ ^2- ]), can be obtained.

The amount of phosphonium salt and/or ammonium salt used in step (D) (the total amount used when two or more types are used) is preferably 0.01 mol or more, more preferably 0.05 mol or more, and even more preferably 0.08 mol or more, and is preferably 1.0 mol or less, more preferably 0.7 mol or less, and even more preferably 0.5 mol or less, per mol of the halosilane compound. If the amount of phosphonium salt and/or ammonium salt is too small, the yield of the salt of the cyclic halosilane compound tends to decrease.

The step (D) is preferably carried out in the presence of a basic compound. Examples of basic compounds include (mono-, di-, tri-, poly-)amine compounds, among which monoamine compounds are preferably used. Specifically, for example, triethylamine, tripropylamine, tributylamine, trioctylamine, triisobutylamine, triisopentylamine, diethylmethylamine, diisopropylethylamine, dimethylbutylamine, dimethyl-2-ethylhexylamine, diisopropyl-2-ethylhexylamine, methyldioctylamine, etc. are preferred, with tributylamine and diisopropylethylamine being particularly preferred. Only one type of basic compound may be used, or two or more types may be used in combination.

The amount of basic compound used in step (D) (total amount when two or more types are used) may be appropriately set according to the type of compound, but is preferably 0.1 mol or more, more preferably 0.2 mol or more, even more preferably 0.4 mol or more, and preferably 2 mol or less, more preferably 1.8 mol or less, and even more preferably 1.5 mol or less, per mol of halosilane compound. The above ranges tend to improve the yield of the salt of the cyclic halosilane compound. When a diamine compound, triamine compound, or polyamine compound is used as the basic compound, the amount (total amount) of the basic compounds (di-, tri-, poly-amine) used is preferably 0.5 mol or less, more preferably 0.4 mol or less, and even more preferably 0.3 mol or less, per mol of halosilane compound.

Step (D) may be carried out in the presence of a chelating ligand such as a polyether compound such as 1,1-dimethoxyethane or 1,2-diphenoxyethane; a polythioether compound; or a multidentate phosphine compound such as 1,2-bis(dimethylphosphino)ethane or 1,3-bis(diphenylphosphino)propane. By carrying out step (D) in the presence of a chelating ligand, the yield of the salt of the cyclic halosilane compound tends to improve. In addition, by appropriately selecting the type of chelating ligand used, it is possible to adjust the number of hydrogen atoms and the composition ratio in the obtained cyclic halosilane compound. The amount of the chelating ligand used may be appropriately set, and may be, for example, 0.01 mol or more, 0.05 mol or more, or 0.1 mol or more per mol of the halosilane compound. In addition, it may be 50 mol or less, 40 mol or less, or 30 mol or less per mol of the halosilane compound.

Step (D) is preferably carried out in the presence of a solvent. As the solvent, it is preferable to use an organic solvent. As the organic solvent, a solvent that does not interfere with the cyclization coupling reaction is preferable, and examples of the organic solvent include halogenated hydrocarbon solvents such as chloroform, dichloromethane, 1,2-dichloroethane, etc., ether solvents such as diethyl ether, tetrahydrofuran, cyclopentyl methyl ether, diisopropyl ether, methyl tertiary butyl ether, etc., and aprotic polar solvents such as acetonitrile, ethyl acetate, N,N-dimethylformamide, etc. Among these, chlorinated hydrocarbon solvents such as chloroform, dichloromethane, 1,2-dichloroethane, etc. are preferably used, and dichloromethane and 1,2-dichloroethane are particularly preferable.

The amount of the solvent used in step (D) is not particularly limited, but it is usually preferable to adjust the concentration of the halosilane compound to 0.5 to 10 mol/L, more preferably 0.8 to 8 mol/L, and even more preferably 1 to 5 mol/L.

The reaction temperature in step (D) may be adjusted appropriately depending on the reactivity, and may be, for example, about 0 to 120°C, and preferably about 15 to 70°C. Here, the reaction temperature means the liquid temperature in the reactor. The reaction temperature can be adjusted, for example, by circulating a temperature control medium in a jacket provided around the reactor, but is not limited to this. The reaction temperature may be set appropriately depending on the reaction temperature and the degree of progress of the reaction, and is, for example, preferably 1 hour or more, more preferably 2 hours or more, even more preferably 3 hours or more, and preferably 48 hours or less, and more preferably 24 hours or less. Furthermore, stirring may be performed simultaneously with heating during the reaction in order to promote the reaction.

The reaction in step (D) is desirably carried out under substantially anhydrous conditions, for example, in an atmosphere of dry gas (particularly an inert gas such as nitrogen gas or argon gas).

In step (D), the method of contacting the halogenated monosilane compound with at least one selected from a phosphonium salt and an ammonium salt is arbitrary, but examples include (1) a method in which at least one selected from a phosphonium salt and an ammonium salt is added to a reactor in advance, and the halogenated monosilane compound is added successively, (2) a method in which the halogenated monosilane compound is added to a reactor in advance, and at least one selected from a phosphonium salt and an ammonium salt is added successively, and (3) a method in which the halogenated monosilane compound and at least one selected from a phosphonium salt and an ammonium salt are each added successively to a reactor. It is preferable to carry out step (D) by the above method (1).

When a solvent is used in step (D), although there are no particular limitations, either one or both of the halogenated monosilane compound and at least one selected from the phosphonium salt and the ammonium salt may be dissolved or dispersed in the solvent before contacting them. It is preferable that at least one selected from the phosphonium salt and the ammonium salt is dissolved or dispersed in the solvent beforehand.

The salt of the cyclic halosilane compound obtained in step (D) can be isolated from the reaction solution by using purification means such as solid-liquid separation, distillation, crystallization, extraction, etc. In particular, when the substituents R ¹ to R ⁴ of the phosphonium salt or ammonium salt are alkyl groups or aryl groups, the salt of the cyclic halosilane compound tends to precipitate in the reaction solution, so the salt of the cyclic halosilane compound can be easily purified by solid-liquid separation. The solid-liquid separation means used in this case are not particularly limited, and known solid-liquid separation means such as filtration, precipitation, centrifugation, decantation, etc. can be used.

<Step (E)>
The method for producing a cyclic silane hydride compound of the present disclosure may optionally include a step of contacting a salt of a cyclic halosilane compound with a Lewis acid compound (hereinafter also referred to as "step (E)"). When the cyclic halosilane compound produced by step (E) is used, the efficiency of step (A) tends to be improved.

The type of Lewis acid compound used in step (E) is not particularly limited, but it is preferable to use a metal halide. Examples of metal halides include metal chlorides, metal bromides, and metal iodides, but it is preferable to use a metal chloride from the viewpoint of reactivity and ease of reaction control. Examples of metal elements constituting the metal halide include Group 13 elements such as boron, aluminum, gallium, indium, and thallium, Group 11 elements such as copper, silver, and gold, Group 4 elements such as titanium and zirconium, iron, zinc, and calcium. Specific examples of Lewis acid compounds include boron halides such as boron trifluoride, boron trichloride, and boron tribromide; aluminum halides such as aluminum chloride and aluminum bromide; gallium halides such as gallium chloride and gallium bromide; indium halides such as indium chloride and indium bromide; thallium halides such as thallium chloride and thallium bromide; copper halides such as copper chloride and copper bromide; silver halides such as silver chloride and silver bromide; gold halides such as gold chloride and gold bromide; titanium halides such as titanium chloride and titanium bromide; zirconium halides such as zirconium chloride and zirconium bromide; iron halides such as iron chloride and iron bromide; zinc halides such as zinc chloride and zinc bromide; calcium halides such as calcium chloride and calcium bromide; and the like.

The amount of the Lewis acid compound used in step (E) may be adjusted as appropriate depending on the reactivity between the salt of the cyclic halosilane compound and the Lewis acid compound, but for example, it is preferably 0.5 moles or more, more preferably 1.5 moles or more, and is preferably 20 moles or less, more preferably 10 moles or less, per mole of the salt of the cyclic halosilane compound.

Step (E) is preferably carried out in a solvent. Examples of the solvent used in the reaction include hydrocarbon solvents such as hexane, heptane, and toluene; ether solvents such as diethyl ether, tetrahydrofuran, cyclopentyl methyl ether, diisopropyl ether, and methyl tertiary butyl ether; and halogenated carbon solvents such as dichloromethane and dichloroethane. Among these, hydrocarbon solvents are preferred, and saturated hydrocarbon solvents such as hexane and heptane are particularly preferred from the viewpoint of separation from the metal salt after the reaction. These organic solvents may be used alone or in combination of two or more. The reaction solvent may be purified by distillation, dehydration, or the like before the reaction in order to remove water and dissolved oxygen contained therein.

In step (E), the amount of solvent used is not particularly limited, but it is usually preferable to adjust the concentration of the salt of the cyclic halosilane compound to 0.005 mol/L or more and 10 mol/L or less, more preferably 0.01 mol/L or more and 5 mol/L or less, and even more preferably 0.05 mol/L or more and 3 mol/L or less.

In step (E), the reaction temperature may be adjusted appropriately depending on the reactivity, but is preferably -80°C or higher, more preferably -50°C or higher, even more preferably -30°C or higher, and is preferably 200°C or lower, more preferably 150°C or lower, and even more preferably 100°C or lower.

In step (E), the atmosphere in which the reaction is carried out is not particularly limited, but in order to suppress the oxidation reaction of the cyclic halosilane compound and its salt, the oxygen concentration of the atmosphere is preferably 9% by volume or less, more preferably 5% by volume or less, even more preferably 3% by volume or less, and particularly preferably 1% by volume or less. In addition, in order to suppress the hydrolysis of the cyclic halosilane compound and its salt, the moisture concentration of the atmosphere is preferably 2000 ppm (volume basis) or less, more preferably 1500 ppm (volume basis) or less, even more preferably 1000 ppm (volume basis) or less, even more preferably 500 ppm (volume basis) or less, even more preferably 150 ppm (volume basis) or less, and particularly preferably 10 ppm (volume basis) or less. Step (E) may be carried out in an inert gas (e.g., nitrogen gas or argon gas) atmosphere or in the dark.

In step (E), the method of contacting the salt of the cyclic halosilane compound with the Lewis acid compound is not particularly limited, but examples include (1) a method in which the salt of the cyclic halosilane compound and the Lewis acid compound are each dissolved or dispersed in a solvent in advance to prepare a solution (or dispersion) of the salt of the cyclic halosilane compound and a solution (or dispersion) of the Lewis acid compound, and then these solutions (or dispersions) are mixed; (2) a method in which the salt of the cyclic halosilane compound and the Lewis acid compound are added simultaneously or sequentially to the solvent; (3) a method in which the Lewis acid compound is added to a solution (or dispersion) of the salt of the cyclic halosilane compound; and (4) a method in which the salt of the cyclic halosilane compound and the Lewis acid compound are charged and then a solvent is added thereto.

The salt of the cyclic halosilane compound used in step (E) can be produced, for example, in step (D). In this case, the reaction liquid in step (D) may be used as is as the solution (or dispersion) of the salt of the cyclic halosilane compound, but a solution (or dispersion) that has been subjected to solid-liquid separation or solvent replacement after step (D) may also be used. The salt of the cyclic halosilane compound used in step (E) may be a salt of the cyclic halosilane compound obtained by any method, such as contacting a halosilane compound with an ammonium salt or a phosphonium salt, or contacting a halosilane compound with a tertiary polyamine.

In step (E), the salt of the cyclic halosilane compound or the Lewis acid compound may be added in one lump, or preferably in a sequential manner. The sequential addition may be in portions, or preferably in a continuous manner.
Step (E) may be a batch reaction or a continuous reaction. When step (E) is carried out as a batch reaction, it is preferable to carry out the step by successively adding the Lewis acid compound to a solution (or dispersion) of the salt of the cyclic halosilane compound.

<Step (F)>
The method for producing a cyclic silane hydrogen compound of the present disclosure may include a step of cyclizing a halosilane compound in the presence of at least one coordination compound selected from the above (i) and (ii). The above-mentioned compounds can be used as the halosilane compound.
The cyclization reaction in step (F) is preferably carried out in the presence of a tertiary amine. Preferred examples of the tertiary amine include triethylamine, tripropylamine, tributylamine, trioctylamine, triisobutylamine, triisopentylamine, diethylmethylamine, diisopropylethylamine (DIPEA), dimethylbutylamine, dimethyl-2-ethylhexylamine, diisopropyl-2-ethylhexylamine, and methyldioctylamine. When a tertiary amine is used in step (F), only one type may be used, or two or more types may be used in combination.

The amounts of the coordination compound, the halosilane compound, and the tertiary amine used in step (F) may be appropriately determined. The coordination compound is preferably used in an amount of 1 mole or more, more preferably 2 moles or more, and more preferably 50 moles or less, and more preferably 10 moles or less, per mole of the halosilane compound. The tertiary amine is preferably used in an amount of 0.5 to 4 moles, and particularly preferably the same amount, per mole of the halosilane compound.
Step (F) can be carried out in an organic solvent, if necessary. Examples of the organic solvent include aprotic polar solvents such as halogenated hydrocarbon solvents (e.g., chloroform, dichloromethane, 1,2-dichloroethane, etc.), ether solvents (e.g., diethyl ether, tetrahydrofuran, cyclopentyl methyl ether, diisopropyl ether, methyl tertiary butyl ether, etc.), acetonitrile, ethyl acetate, etc. Among these, chlorinated hydrocarbon solvents such as chloroform, dichloromethane, 1,2-dichloroethane, etc. are preferred, and dichloromethane and 1,2-dichloroethane are particularly preferred. These organic solvents may be used alone or in combination of two or more. The amount of the organic solvent used is not particularly limited, but is usually adjusted so that the concentration of the halosilane compound is 0.5 to 10 mol/L, more preferably 0.8 to 8 mol/L, and even more preferably 1 to 5 mol/L.

The reaction temperature in step (F) can be set appropriately depending on the reactivity, for example, about 0 to 120°C, preferably about 15 to 70°C.

<Other processes>
The method for producing a cyclic silane hydrogen compound according to the present disclosure may include any other steps in addition to the steps described above (hereinafter, also referred to as "other steps"). Examples of the other steps include a solid-liquid separation step, a liquid-liquid separation step, an extraction step, a washing step, a purification step, a concentration step, a dilution step, etc.

[Uses of the cyclic silane hydride compounds of the present disclosure]
The cyclic silane hydride compound obtained by the method for producing the cyclic silane hydride compound of the present disclosure can be used as a raw material for chemical vapor deposition (CVD) or atomic layer deposition (ALD) to produce a silicon-containing film. There is no particular limitation on the CVD, and it can be used for thermal CVD, photo CVD, plasma CVD, epitaxial CVD, etc.

The cyclic hydrogenated silane compound obtained by the method for producing a cyclic hydrogenated silane compound disclosed herein can be photopolymerized, etc., and therefore can be used to produce a silicon-containing film by a liquid-phase process.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass."

Example 1
(1. Production Examples of Salts of Cyclic Halosilane Compounds)
After replacing the inside of a 2L four-neck flask equipped with a thermometer, a condenser, a dropping funnel and a stirrer with nitrogen gas, 123.5g (0.59mol) of tetraethylammonium bromide, 490.0g (2.64mol) of tributylamine and 702.7g of dichloromethane were placed in the flask. Then, while stirring the solution in the flask, a solution consisting of 238.1g (1.76mol) of trichlorosilane and 117.2g of dichloromethane was slowly dropped from the dropping funnel under a condition of 25°C. After the dropping was completed, the mixture was stirred for 2 hours, and then stirred while heating at 50°C for 6 hours, thereby carrying out a cyclization coupling reaction. After the reaction, the obtained solid was filtered and purified to obtain 102.7g of a salt of a cyclic halosilane compound.

(2. Production Examples of Cyclic Halosilane Compounds)
In a nitrogen atmosphere, 15.0 g of the white solid obtained in (1) above and 4.6 g of powdered aluminum chloride (AlCl ₃ ) were placed in a 300 mL three-neck flask equipped with a stirrer, and 98.7 g of hexane was further added as a solvent. The mixture was reacted for 3 hours at room temperature under a light-shielded condition while stirring, and then filtered and concentrated to obtain a hexane solution of a cyclic halosilane compound (concentration: about 37% by mass).

(3. Production Examples of Cyclic Hydrogensilane Compounds)
After replacing the inside of a 300 mL three-neck flask equipped with a dropping funnel and a stirrer with nitrogen gas, 49 g of the hexane solution of the cyclic halosilane compound obtained in Example 1 (2) above was added. While stirring the solution in the flask, 100 mL of a diethyl ether solution of lithium aluminum hydride (concentration: about 1.0 mol/L) was gradually dropped from the dropping funnel under 0°C conditions, and then the mixture was stirred at 25°C for 1 hour to carry out a reduction reaction. After the reaction, the resulting reaction solution was slowly dropped into a 10% aqueous sulfuric acid solution cooled to 0°C. After stirring at room temperature for 30 minutes, a colorless and transparent solution containing no solids was obtained in both the organic layer and the aqueous layer. After leaving the mixture to stand, the aqueous layer was removed by separation to recover the organic layer, and the organic layer was concentrated under reduced pressure to obtain 5.7 g of a crude product. At this time, no solids were found to adhere to the top of the concentrator or the cooler for solvent condensation.
This crude product was further purified by vacuum distillation using a 100 mL glass distillation apparatus to obtain 2.8 g of colorless, transparent cyclohexasilane with an area purity of 98% by gas chromatography (GC). No solid matter was found adhering to the top of the distillation apparatus or the condensation cooler after distillation.
Furthermore, as a result of analysis by gas chromatography (GC) and NMR, no aluminum complex (complex of aluminum chloride and diethyl ether solvent) was detected in the obtained distilled product.
Furthermore, the amount of chlorine in the distillate was confirmed to be 4 ppm using an ion chromatograph (manufactured by DIONEX, "ICS-2000").

<Comparative Example 1>
(Comparative Production Example of Cyclic Hydrogensilane Compound)
After the atmosphere in a 500 mL three-neck flask equipped with a dropping funnel and a stirrer was replaced with nitrogen gas, 136.1 g of a hexane solution of a cyclic halosilane compound obtained under the same conditions as in Example 1 (2) was placed in. While stirring the solution in the flask, 314 mL of a diethyl ether solution of lithium aluminum hydride (concentration: about 1.0 mol/L) was gradually added dropwise from the dropping funnel at 0° C., and the solution was then stirred at 25° C. for 1 hour to carry out a reduction reaction.
After the reaction, the reaction solution containing the salt of the obtained solid residue was transferred to a filter and filtered under a nitrogen atmosphere to remove the salt of the generated solid residue. Note that the adhesion of the solid residue to the inside of the transfer pipe was observed.
The filtrate was then concentrated under reduced pressure to half its volume by distilling off the solvent, yielding a concentrated solution consisting of an upper layer containing cyclohexasilane and a lower layer containing solid residues. At this time, it was confirmed that solids had adhered to the top of the concentrator and the cooler for condensing the solvent.
Next, this concentrated liquid was subjected to solid-liquid separation by filtration, and the obtained filtrate was further concentrated under reduced pressure, and again filtered to remove the lower layer containing the resulting solid residue, thereby obtaining 11.6 g of a crude product.
Furthermore, 8.4 g of this crude product was purified by vacuum distillation using a 100 mL glass distillation apparatus, yielding 6.9 g of cyclohexasilane with an area purity of 98% as determined by gas chromatography (GC).
At this time, it was confirmed that solids had adhered to the top of the distillation apparatus after distillation and to the condensation cooler, etc.

In addition, part of the distillate (initial distillate) during distillation was observed to be cloudy, and analysis by gas chromatography (GC) and NMR confirmed that it contained an aluminum complex (a complex of aluminum chloride and diethyl ether solvent).
Furthermore, the amount of chlorine in the distillate was measured using an ion chromatograph (manufactured by DIONEX, "ICS-2000"), and it was found to be 2,900 ppm.

From the above, it has become clear that the manufacturing method disclosed herein can suppress adhesion of components derived from the reducing agent to the manufacturing equipment, can efficiently remove impurities derived from the reducing agent, etc., and can efficiently produce cyclic hydrogen silane.

Claims (13)

A step (A) of contacting one or more selected from a cyclic halosilane compound, a salt of a cyclic halosilane compound, and a complex of a cyclic halosilane compound with a reducing agent;
A step (B) of contacting the reduction reaction solution obtained in the step (A) with an acidic aqueous solution;
The present invention relates to a method for producing a cyclic silane hydride compound having the formula: A method for producing the cyclic silane hydrogen compound according to claim 1, comprising step (C) of distilling the cyclic silane hydrogen compound. The method for producing a cyclic hydrogen silane compound according to claim 1 or 2, wherein the salt of the cyclic halosilane compound is obtained by step (D) of contacting a halogenated monosilane compound with at least one selected from a phosphonium salt and an ammonium salt. The method for producing a cyclic hydrogen silane compound according to any one of claims 1 to 3, wherein the cyclic halosilane compound is obtained by step (E) of contacting a salt of the cyclic halosilane compound with a Lewis acid compound. The method for producing a cyclic hydrogenated silane compound according to any one of claims 1 to 4, wherein the concentration of the acidic substance in the acidic aqueous solution 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 5, wherein the acidic aqueous solution contains at least one selected from hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid. The method for producing a cyclic hydrogen silane compound according to any one of claims 1 to 6, wherein the solvent is used in step (A) such that the total amount of the cyclic halosilane compound and the like used per 1 L of the solvent is 0.01 mol or more and 5.0 mol or less. The method for producing a cyclic hydrogenated silane compound according to any one of claims 1 to 7, wherein step (B) is carried out without a solid-liquid separation step after step (A). The method for producing a cyclic silane hydrogen compound according to any one of claims 1 to 8, wherein the reduction reaction solution contains a cyclic silane hydrogen compound and an aluminum complex. The method for producing a cyclic hydrogen silane compound according to claim 9, wherein the aluminum complex is a complex of aluminum or an aluminum halide and an ether-based solvent. The method for producing a cyclic hydrogen silane compound according to any one of claims 1 to 10, wherein step (A) is carried out in the presence of at least one solvent selected from a hydrocarbon solvent and an ether solvent. The method for producing a cyclic silane hydride compound according to any one of claims 1 to 11, wherein the reducing agent is at least one selected from an aluminum hydride compound, a boron hydride compound, a silicon hydride compound, a tin hydride compound, and a transition metal hydride compound. The method for producing a cyclic silane hydrogen compound according to any one of claims 1 to 12, wherein the cyclic silane hydrogen compound includes cyclohexasilane and/or cyclopentasilane.