Silanol compounds, methods for producing the silanol compounds, and compositions containing the silanol compounds

Abstract

To provide a novel silanol compound that does not undergo dehydration condensation and can be isolated as a single powder even without a crystal solvent.SOLUTION: An acidic compound is added to a dispersion containing dodecapotassium-2,4,6,8,10,12,14,16,18,20,22,24,25,26,27,28,29,30-octadecaoxa-1,3,5,7,9,11,13,15,17,19,21,23-dodecasilaheptacyclo[13.9.1.13,13.15,11.17,21.19,19.117,23]triacontane-1,3,5,7,9,11,13,15,17,19,21,23-dodecakis(olate)bis(α-dextrin)hydrate and the mixture is subjected to a proton-exchange reaction to obtain a cage-type silsesquioxane represented by (HOSiO1.5)12.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to silanol compounds, methods for producing said silanol compounds, and compositions containing said silanol compounds. [Background technology]

[0002] By controlling and constructing materials at the atomic level, unprecedented physical properties can be achieved, making them useful materials. For example, fullerenes, carbon nanotubes, and graphene are nanocarbon materials in which carbon is assembled in 0, 1, and 2 dimensions, and each possesses unique physical properties.

[0003] SiO2, like carbon, is an inexhaustible material on Earth and has been used in various fields to date. As a method for obtaining SiO2 materials constructed by controlling SiO2 at the atomic level, similar to nanocarbon materials, it is considered efficient to assemble orthosilicic acid (Si(OH)4), the basic unit of SiO2 represented by the following formula. [ka]

[0004] Orthosilicic acid is known to be synthesized and isolated, for example, by reacting a silicon compound having a benzyl protecting group that can be removed by hydrocracking in the presence of a Pd or Pt / C catalyst (see, for example, Non-Patent Document 1). Furthermore, the synthesis and isolation of orthosilicic acid dimers, cyclic trimers, and cyclic tetramers, as represented by the following formulas, have been successfully achieved using the above method. These oligomers of orthosilicic acid, such as dimers, trimers, and cyclic tetramers, are also useful as raw materials for obtaining SiO2 materials. [ka] [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Nature Communications, 2017, 8, 140. [Overview of the project] [Problems that the invention aims to solve]

[0006] However, although orthosilicic acid (Si(OH)4), its dimers, cyclic trimers, and cyclic tetramers have been successfully synthesized and isolated, they are unstable in the presence of water and readily undergo dehydration condensation, leaving room for improvement in handling. In particular, the cage-type octamer (Q8H8) of orthosilicic acid (Si(OH)4), shown in the formula below, undergoes dehydration condensation unless a crystalline solvent (such as an amide solvent) that stabilizes its coordination is present, making it impossible to isolate it as a standalone powder. [ka]

[0007] Generally, silanol compounds are far more advantageous in materials development when used as standalone powders that have not been solvated in a crystalline solvent.

[0008] Therefore, the present invention aims to provide a novel oligomeric silanol compound of orthosilicic acid that can be isolated as a single powder without the need for a crystalline solvent, without undergoing dehydration condensation. [Means for solving the problem]

[0009] As a result of diligent research, the inventors of the present invention have found that the cage-type dodecamer of orthosilicic acid (Q 12 H 12 However, we discovered that even without a crystalline solvent, dehydration condensation does not occur, and the material can be isolated as a single powder, thus completing the present invention.

[0010] In other words, the present invention includes the following embodiments. [1] A silanol compound represented by the following formula (1). [ka] [2] A composition comprising the silanol compound described in [1]. [3] The composition according to [2], wherein the content of the silanol compound is 0.1 to 99.9% by mass. [4] The composition according to [2] or [3] further comprises at least one selected from the group consisting of water, ether compounds, amine compounds, amide compounds, ammonium salts, and metal complexes. [5] A method for producing a silanol compound, comprising a proton exchange step of reacting a silicate having the structure represented by the following formula (1)' with an acidic compound to obtain a solution containing a silanol compound represented by the following formula (1). [ka] (In formula (1)', Q + (This represents a positive ion.) [ka] [6] A method for producing a silanol compound according to [5], further comprising the steps of adding a poor solvent for precipitating the silanol compound represented by formula (1) to the solution obtained in the proton exchange step, precipitating the silanol compound represented by formula (1), and isolating the silanol compound represented by formula (1) as a powder. [7] A method for producing a silanol compound according to [5] or [6], wherein the acid dissociation constant pKa of the acidic compound in dimethyl sulfoxide (DMSO) is -1 to 20. [8] A method for producing a silanol compound according to any one of [5] to [7], wherein the acid dissociation constant pKa of the acidic compound in dimethyl sulfoxide (DMSO) is 12.6 or less. [9] A method for producing a silanol compound according to any one of [5] to [8], wherein the acidic compound is an inorganic acid.

[10] The method for producing a silanol compound according to [9], wherein the inorganic acid is hydrochloric acid or nitric acid.

[11] The method for producing a silanol compound according to [9], wherein the inorganic acid is hydrochloric acid.

[12] A method for producing a silanol compound according to any one of [5] to [8], wherein the acidic compound is at least one selected from the group consisting of acetic acid and compounds having a structure represented by the following formulas (b-1) to (b-5). [ka] (In formulas (b-1) to (b-5), X is independently an oxygen atom, a sulfur atom, or an amino group (-NR) 3 -) to, R 1 R is a hydrogen atom or a hydrocarbon group having 1 to 14 carbon atoms. 2 Each of these independently represents a hydrogen atom or a hydrocarbon group with 1 to 14 carbon atoms.

[13] The method for producing a silanol compound according to

[12] , wherein the acidic compound is a resin having at least one structure selected from the group consisting of structures represented by formulas (b-2) to (b-5).

[14] A method for producing a silanol compound according to any one of [5] to

[13] , wherein the proton exchange step is performed in at least one liquid selected from the group consisting of water, ether-based liquids, alcohol-based liquids, amide-based liquids, ester-based liquids, halogen-based liquids, and aprotic polar liquids. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a novel silanol compound that does not undergo dehydration condensation even without a crystalline solvent and can be isolated as a single powder. [Brief explanation of the drawing]

[0012] [Figure 1] This shows the 29Si-NMR measurement results of the product obtained in Example 1. [Figure 2] This shows the high-resolution mass spectrometry (TOF-MS) measurement results of the product obtained in Example 1. [Figure 3] This is an example of a proton exchange reaction equation for producing a silanol compound by reacting a silicate having the structure represented by formula (1)' with an inorganic acid (e.g., hydrochloric acid). [Modes for carrying out the invention]

[0013] The following describes in detail embodiments for carrying out the present invention (hereinafter abbreviated as "this embodiment"). It should be noted that the present invention is not limited to the following embodiments, and can be implemented in various modifications within the scope of its gist.

[0014] <Silanol compounds> The silanol compound of this embodiment is represented by the following formula (1). [ka] The silanol compound of this embodiment, having the structure described above, does not undergo dehydration condensation even without a crystalline solvent and can be isolated as a single powder. Conventional silanol compounds (for example, the cage-type octamer (Q8H8) of orthosilicic acid (Si(OH)4)) cannot be isolated as individual powders because dehydration condensation proceeds if a crystalline solvent (such as an amide solvent) that stabilizes coordination is not present. On the other hand, the silanol compound of this embodiment can maintain a stable state as a powder on its own (for example, with a purity of 100%), making it easy to handle and extremely advantageous in material development. In this embodiment, the silanol compound represented by formula (1) can be confirmed by various NMR, high-resolution mass spectrometry, and X-ray crystal structure analysis.

[0015] <Method for producing silanol compounds> The method for producing a silanol compound according to this embodiment includes a proton exchange step (hereinafter, may be abbreviated as "proton exchange step") of reacting a silicate having a structure represented by the following formula (1)' (hereinafter, may be abbreviated as "silicate") with an acidic compound to obtain a solution containing a silanol compound represented by the following formula (1). [Chemical formula] (In formula (1)', Q + represents a cation.) [Chemical formula] Further, the method for producing a silanol compound according to this embodiment preferably further includes a step of adding a poor solvent to the solution obtained in the proton exchange step to precipitate the silanol compound represented by the formula (1) and isolating the silanol compound represented by the formula (1) as a powder (hereinafter, may be abbreviated as "isolation step").

[0016] Hereinafter, the silicate, acidic compound, and other reaction conditions in the proton exchange step will be described in detail.

[0017] (Proton exchange step) The specific type of silicate, the specific type of acidic compound, the amount of the acidic compound used, the type of the reaction medium which is a solvent or a dispersion medium, the reaction conditions, etc. used in the proton exchange step are not particularly limited and can be appropriately selected according to the purpose.

[0018] As the acidic compound used in the proton exchange step, an acidic compound having an acid dissociation constant pKa (hereinafter, may be abbreviated as "pKa(DMSO)") of -1 to 20 in dimethyl sulfoxide (DMSO) is preferable.

[0019] By performing proton exchange with an acidic compound having a pKa(DMSO) of -1 to 20, a silanol compound can tend to be efficiently produced. When the pKa(DMSO) is -1 to 20, the cation (Q + ) of the silicate and the proton (H +The exchange of protons proceeds efficiently, while side reactions are suppressed. As a result, the silanol compound itself can be synthesized in high yield. Furthermore, the method for producing the silanol compound in this embodiment is very suitable for industrial production because the reaction proceeds rapidly under mild conditions. Note that the smaller the pKa(DMSO), the faster the proton exchange step tends to proceed.

[0020] Furthermore, pKa(DMSO) refers to a known value calculated from the concentrations of each component in the acid dissociation equilibrium of acidic compounds in DMSO at 25°C. Specifically, it is the logarithmic value of the value Ka calculated by the following formula.

[0021]

number

[0022] In the proton exchange step, a silicate having the structure represented by the following formula (1)' is reacted with an acidic compound. [ka] (In formula (1)', Q + (This represents a positive ion.) In formula (1)', Q + The cation is not particularly limited, but for example, lithium ion (Li + ), sodium ions (Na + ), potassium ions (K + Alkali metal ions such as (Mg) and magnesium ions (Mg 2+ ), and calcium ions (Ca 2+ Alkaline earth metal ions such as ) and iron(III) ions (Fe 3+ ), copper(II) ion (Cu 2+ ), and zinc ions (Zn 2+ ) transition metal ions such as ammonium ions (NH4 + ), tetramethylammonium ion (NMe4 + ), ethyltrimethylammonium ion (NEtMe3 + ), diethyldimethylammonium ion (NEt2Me2+ ), triethylmethylammonium ion (NEt3Me + ), tetraethylammonium ion (NEt4 + ), tetrapropylammonium ion (NPr4 + ), and tetrabutylammonium ion (NBu4 + Examples of ammonium ions include sodium ions (Na). + ), potassium ions (K + ), tetramethylammonium ion (NMe4 + ), tetraethylammonium ion (NEt4 + ), and ethyltrimethylammonium ion (NEtMe3 + ) is particularly preferable.

[0023] In the proton exchange step, the silicate reacted with the acidic compound is not particularly limited, but for example, a cage-type potassium silicate dodecamer (Q) in which two α-cyclodextrins (αCD) are coordinated vertically, as shown in the following formula described in Angew. Chem. Int. Ed. Engl. 1997, 36, 743. 12 K 12 ) hydrate (dodecapotassium-2,4,6,8,10,12,14,16,18,20,22,24,25,26,27,28,29,30-octadecaoxa-1,3,5,7,9,11,13,15,17,19,21,23-dodecasilaheptacyclo[13.9.1.1 3,13 .1 5,11 .1 7,21 .1 9,19 .1 17,23 ]Triacontane-1,3,5,7,9,11,13,15,17,19,21,23-Dodecais(olate)bis(α-dextrin) hydrate ((Hereafter, "Q 12 K 12 It is sometimes abbreviated as "·2αCD·nH2O". [ka] Such Q 12 K 122αCD·nH2O can be prepared, but is not particularly limited, by referring to, for example, the descriptions in Angew. Chem. Int. Ed. Engl. 1997, 36, 743. and Crystals 2018, 8, 457.

[0024] The acidic compound is preferably an acidic compound with a pKa(DMSO) of -1 to 20. The pKa(DMSO) of the acidic compound is preferably 0 or higher, more preferably 1 or higher, even more preferably 2 or higher, preferably 16 or lower, more preferably 14 or lower, and even more preferably 8 or lower. When the pKa(DMSO) of the acidic compound is within the above range, silanol compounds can be produced efficiently.

[0025] Specific examples of acidic compounds are not particularly limited, but include, for example, inorganic acids such as nitric acid (pKa(DMSO) 1.4), sulfuric acid (pKa1(DMSO) 1.4, pKa2(DMSO) 14.7), hydrochloric acid (pKa(DMSO) 2.1), phosphoric acid (pKa1(DMSO) 1.83, pKa2(DMSO) 6.43, pKa3(DMSO) 11.46), and organic acids, which are at least one selected from the group consisting of acetic acid or compounds having a structure represented by the following formulas (b-1) to (b-5). [ka] (In formulas (b-1) to (b-5), X is independently an oxygen atom, a sulfur atom, or an amino group (-NR) 3 -) to, R 1 R is a hydrogen atom or a hydrocarbon group having 1 to 14 carbon atoms. 2 Each of these independently represents a hydrogen atom or a hydrocarbon group with 1 to 14 carbon atoms.

[0026] When a proton exchange reaction using an organic acid is carried out in a reaction medium such as N,N-dimethylacetamide (hereinafter also referred to as "DMAc") or methanol (hereinafter also referred to as "MeOH"), the resulting ammonium salt or alkali metal salt dissolves in the reaction medium. For this reason, it is preferable to separate the by-product ammonium salt or alkali metal salt by column purification or the like. On the other hand, when a proton exchange reaction using an inorganic acid is carried out in a reaction medium such as tetrahydrofuran (hereinafter also referred to as "THF"), the resulting ammonium salt or alkali metal salt, as well as α-dextrin and chemical species derived from α-dextrin, are not easily soluble in the reaction medium. For this reason, the ammonium salt or alkali metal salt can be separated by simple separation means such as filter filtration, and a silanol compound solution is obtained as a filtrate. For this reason, it is preferable that the acidic compound is an inorganic acid.

[0027] Among inorganic acids, nitric acid, sulfuric acid, hydrochloric acid, and phosphoric acid are preferred, with nitric acid or hydrochloric acid being more preferred, and hydrochloric acid being particularly preferred. Hydrochloric acid is inexpensive, and yields tend to be higher when hydrochloric acid is used.

[0028] In addition, the wavy lines in formulas (b-2) to (b-5) above indicate that the structure beyond the line is arbitrary. For example, an acidic compound may contain functional groups that do not participate in the reaction. Therefore, for example, an acidic compound having the structure represented by formula (b-4) above may be a compound that contains a hydrocarbon group such as a methyl group beyond the oxygen atom corresponding to X, as shown in the formula below, such as dimethyl malonate. Furthermore, for example, an acidic compound having the structure represented by formula (b-4) above may be a compound in which the hydrocarbon group beyond the oxygen atom corresponding to X is bonded to form a cyclic structure, as shown in the formula below, such as meldramic acid.

[0029] [ka]

[0030] The structures represented by formulas (b-1) to (b-5) above are so-called β-dicarbonyl structures, and it is known that the hydrogen atom of the methylene group sandwiched between the two carbonyl groups, i.e., the α-hydrogen, acts as an acid site. By having the structures represented by formulas (b-1) to (b-5) above, acidic compounds exhibit an appropriate acid dissociation constant, and the electrons of the anion generated by proton dissociation are delocalized within the structure. For example, an acidic compound having the structure represented by formula (b-2) above undergoes proton dissociation as shown in the following formula. For this reason, it is thought that acidic compounds having the structures represented by formulas (b-1) to (b-5) above have the basicity and nucleophilicity of the anion suppressed, and side reactions can be effectively inhibited.

[0031] [ka]

[0032] X is an amino group (-NR 3 Examples of - include secondary amino groups (-NH-). X is particularly preferably an oxygen atom. 1 When R is a hydrocarbon group, the number of carbon atoms is preferably 6 or less, more preferably 5 or less, and even more preferably 4 or less. 1 The group is not particularly limited and includes, for example, a hydrogen atom, a methyl group (-Me), an ethyl group (-Et), an n-propyl group (-nPr), an i-propyl group (-iPr), and an n-butyl group (-nBu) and a phenyl group (-Ph), but a hydrogen atom is preferred.

[0033] R 2 When R is a hydrocarbon group, the number of carbon atoms is preferably 5 or less, more preferably 4 or less, and even more preferably 3 or less. 2 Examples of such groups include hydrogen atoms, methyl groups (-Me), ethyl groups (-Et), n-propyl groups (-nPr), i-propyl groups (-iPr), and n-butyl groups (-nBu), but hydrogen atoms are preferred.

[0034] The acidic compound represented by formula (b-4) above is not particularly limited, but examples include the acidic compound represented by the following formula (b-4-1). The acidic compound represented by formula (b-5) above is, for example, the acidic compound represented by the following formula (b-5-1).

[0035] [ka] (In equations (b-4-1) and (b-5-1), R 1 R is a hydrogen atom or a hydrocarbon group having 1 to 14 carbon atoms. 4 (These represent divalent hydrocarbon groups with 1 to 14 carbon atoms.)

[0036] R 4 Examples of such groups are not particularly limited, but include methylene group (-CH2-), ethylene group (-CH2CH2-), n-propylene group (-CH2CH2CH2-), dimethylmethylene group (-C(CH3)2-), and i-propylene group (-CH(CH3)CH2-).

[0037] Specific examples of acidic compounds are not limited to acetic acid (pKa(DMSO) 12.6), benzoic acid (pKa(DMSO) 11.1), meldrumic acid (pKa(DMSO) 7.3), meldrumic acid derivatives, dimedone (pKa(DMSO) 11.2), dimedone derivatives, acetylacetone (pKa(DMSO) 13.3), and acetylacetone derivatives (see formula below).

[0038] [ka]

[0039] As the acidic compound, low molecular weight compounds such as meldrum acid, or compounds represented by formulas (b-2) to (b-5) above can be introduced into organic solid materials such as resins, or inorganic solid materials such as silica or carbon. When the acidic compound is such a solid, it can be packed into a column and used like an ion exchange resin. Therefore, silanol compounds can be produced very efficiently. As the acidic compound, general solid acids (for example, amberlist or amberlite) may also be used.

[0040] In particular, the acidic compound is preferably a resin having at least one structure selected from the group consisting of formulas (b-2) to (b-5) above, and is preferably regenerated as an acidic compound by exposing it to an acidic aqueous solution such as hydrochloric acid after a proton exchange process.

[0041] The amount of acidic compound used in the proton exchange step is typically 1 or more, preferably 1.5 or more, more preferably 2.0 or more, in terms of molar amount relative to the silicate, and typically 50 or less, preferably 20 or less, and more preferably 5 or less. When the amount of acidic compound used is within the above range, silanol compounds can be produced efficiently.

[0042] The reaction in the proton exchange step is preferably carried out in a liquid (reaction medium). Such reaction mediums are not particularly limited, but examples include ether-based liquids such as tetrahydrofuran (THF), tetrahydropyran, dioxane, diethyl ether (Et2O), dimethyl ether, diisopropyl ether, diphenyl ether, methyl ethyl ether, diethylene glycol dimethyl ether, and triethylene glycol dimethyl ether; alcohol-based liquids such as methanol, ethanol, n-propanol, and i-propanol; amide-based liquids such as formamide, N,N-dimethylformamide (DMF), acetamide, N-methylacetamide, N,N-dimethylacetamide (DMAc), urea, and tetramethylurea; ester-based liquids such as ethyl acetate, n-amyl acetate, and ethyl lactate; halogen-based liquids such as methylene chloride, chloroform, carbon tetrachloride, tetrachloroethane, and hexachloroethane; acetonitrile, acetone, methyl ethyl ketone, phenyl methyl ketone, dimethyl sulfoxide (DMSO); and water. Furthermore, the reaction medium is not limited to one type; two or more types may be combined.

[0043] The amount of reaction medium used in the proton exchange step is preferably such that the silicate content is 0.005 to 0.04 mol / L. This silicate content allows for the efficient production of silanol compounds. The reaction temperature in the proton exchange step is usually -80°C or higher, preferably 0°C or higher, more preferably 20°C or higher, and usually 200°C or lower, preferably 70°C or lower, more preferably 40°C or lower. The reaction time in the proton exchange step is usually 48 hours or less, preferably 24 hours or less, more preferably 8 hours or less, and particularly preferably 1 hour or less. Within the above range, silanol compounds can be produced efficiently.

[0044] (Isolation process) The method for producing the silanol compound of this embodiment preferably includes a step of adding a poor solvent to the solution of the silanol compound represented by formula (1) obtained in the proton exchange step, thereby precipitating the silanol compound represented by formula (1) and isolating the silanol compound represented by formula (1) as a powder. By including such a step, the method for producing the silanol compound of this embodiment can be isolated as a single powder very easily without the need for a crystalline solvent, and without dehydration condensation.

[0045] The poor solvent for precipitating the silanol compound represented by formula (1) above is not particularly limited, but examples include hexane, benzene, toluene, dibutyl ether, diisopropyl ether, diethyl ether, dichloromethane, chloroform, and ethyl acetate. Among these, hexane, benzene, diisopropyl ether, and ethyl acetate are preferred, and diethyl ether and ethyl acetate are particularly preferred. Furthermore, in the isolation process, a precursor (e.g., Q) to which a ligand (e.g., αCD) is coordinated is used as the silicate to react with the acidic compound. 12 K 12 When using (2αCD·nH2O), it is preferable to use a solvent that dissolves the ligand and its decomposition products (e.g., αCD and its decomposition products) as a poor solvent for precipitating the silanol compound represented by formula (1) above. The boiling point of the poor solvent used to precipitate the silanol compound represented by formula (1) above is usually 0°C or higher, preferably 10°C or higher, more preferably 30°C or higher, and usually 300°C or lower, preferably 200°C or lower, more preferably 150°C or lower.

[0046] Furthermore, it is preferable to concentrate the solution obtained in the proton exchange step by filtering out the salt produced in the reaction and then concentrating the filtrate. By using this concentrate, the silanol compound represented by formula (1) can be precipitated more efficiently.

[0047] In the isolation step, the time for precipitating the silanol compound represented by formula (1) is not particularly limited and can be selected as appropriate. It is usually 24 hours or less, preferably 12 hours or less, more preferably 6 hours or less, and usually 0.25 hours or more, preferably 0.5 hours or more, more preferably 1 hour or more. When precipitating the silanol compound, stirring will result in more uniform precipitated particles, making it easier to powderize in the drying step.

[0048] Methods for isolating the silanol compound represented by formula (1) above as a powder are not particularly limited, but include, for example, filtration. Furthermore, it is preferable to dry the powder of the silanol compound represented by formula (1) obtained by such an isolation method. The drying temperature, drying pressure, drying time, etc., are not particularly limited and can be appropriately selected depending on the purpose.

[0049] <Composition> The composition of this embodiment contains a silanol compound represented by the above formula (1). In the composition of this embodiment, the types of compounds other than the silanol compound represented by formula (1) are not particularly limited and can be appropriately selected according to the purpose. As mentioned above, the silanol compound of this embodiment can be isolated as a powder (purity: 100%), so the content of the silanol compound represented by formula (1) in the composition of this embodiment can be adjusted as appropriate. The content of the silanol compound represented by formula (1) in the composition of this embodiment is not particularly limited, but for example, it is preferably 0.1 to 99.9% by mass, more preferably 25 to 50% by mass, even more preferably 50 to 70% by mass, and particularly preferably 70 to 99% by mass.

[0050] In the composition of this embodiment, compounds other than the silanol compound represented by formula (1) are not particularly limited, but examples include water, ether compounds, amine compounds, amide compounds, ammonium salts, and metal complexes.

[0051] The amine compound is not limited to any specific type, as long as it has an amino group (which may be a primary, secondary, or tertiary amine). Compounds having both an amino group and an amide group are classified as "amide compounds." Examples of amine compounds include aniline (NH2Ph), diphenylamine (NHPh2), dimethylpyridine (Me2Pyr), di-tert-butylpyridine (tBu2Pyr), pyrazine (Pyraz), triphenylamine (NPh3), triethylamine (Et3N), and di-isopropylethylamine (iPr2EtN). Among the amine compounds, aniline (NH2Ph) is particularly preferred. The composition is not limited to one type of amine compound, but may contain two or more types.

[0052] The content of the amine compound in the composition of this embodiment (total content if two or more types are included) is preferably more than 0.1% by mass, more preferably 1% by mass or more, even more preferably 10% by mass or more, and usually less than 95% by mass, preferably 80% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less.

[0053] The specific type of amide compound is not limited as long as it contains an amide bond. Examples of amide compounds include those represented by the following formulas (i) or (ii).

[0054] [ka] (In formulas (i) and (ii), R' and R'' each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.)

[0055] R' and R'' are not particularly limited, but examples include a hydrogen atom, a methyl group (-Me), an ethyl group (-Et), an n-propyl group (-nPr), an i-propyl group (-iPr), and a phenyl group (-Ph). The compound represented by formula (i) is not particularly limited, but examples include formamide, DMF, acetamide, N-methylacetamide, and DMAc. The compound represented by formula (ii) is not particularly limited, but examples include urea and tetramethylurea (Me4Urea). The content of the amide compound in the composition of this embodiment (total content if two or more types are included) may be 0% by mass (not included) or more and 90% by mass or less.

[0056] The specific type of ammonium salt is not particularly limited, as long as it is a compound consisting of an ammonium ion and a counter anion. The ammonium ion is not particularly limited, but for example, tetrahydroammonium ion (NH4) + ), tetramethylammonium ion (NMe4 + ), tetraethylammonium ion (NEt4 + ), tetrapropylammonium ion (NPr4 + ), tetrabutylammonium ion (NBu4 + ), benzyltributylammonium ion (NBnBu3 + ), tributyl(methyl)ammonium (NBu3Me + ) ions, tetrapentylammonium ions (NPen4 + ), tetrahexylammonium ion (NHex4 + ), tetraheptylammonium ion (NHep4 + ), 1-butyl-1-methylpyrrolidium ion (BuMePyr + ), methyltrioctylammonium ion (NMeOct3 + ), dimethyl dioctadecylammonium ion, hydropyridinylium ion (C5H5N + H), hydroanilinium ion (PhNH2) +Examples include H), trimethyladamantylammonium ion and meldrumate ion. Also, as a counter anion, for example, fluoride ion (F) - ), chloride ions (Cl - ), bromide ions (Br - ), iodide ion (I - ), acetoxyion (AcO - ), nitrate ion (NO3 - ), azide ions (N3 - ), tetrafluoroborate ion (BF4 - ), perchlorate ion (ClO4 - ), and sulfate ions (HSO4 - ) are some examples.

[0057] Particularly preferred ammonium salts include tetrabutylammonium chloride (NBu4Cl), tetrabutylammonium bromide (NBu4Br), tetrapentylammonium chloride (NPen4Cl), dimethyldioctadecylammonium chloride, trimethyladamantylammonium hydroxide, and meldramic acid-tetramethylammonium salt. The composition is not limited to one type of ammonium salt, but may contain two or more types.

[0058] The ammonium salt content (total content if two or more types are included) in the composition of this embodiment is preferably more than 0.1% by mass, more preferably 50% by mass or more, usually less than 95% by mass, and preferably 80% by mass or less. Furthermore, the ratio of the ammonium salt to the silanol compound (total amount of ammonium salt / total amount of silanol compound) in the composition of this embodiment is preferably greater than 0, more preferably 1 or more, usually 12 or less, preferably 8 or less, and more preferably 6 or less. [Examples]

[0059] The embodiment will be described in more detail below using specific examples, but this embodiment is not limited in any way to the following examples.

[0060] [Example 1] Q 12 H 12 Synthesis of Dodecacalcium-2,4,6,8,10,12,14,16,18,20,22,24,25,26,27,28,29,30-octadecaoxa-1,3,5,7,9,11,13,15,17,19,21,23-dodecasilaoctacyclo[13.9.1.1 3,13 .1 5,11 .1 7,21 .1 9,19 .1 17,23 triacontane-1,3,5,7,9,11,13,15,17,19,21,23-dodecakis(olate) bis(α-dextrin) hydrate (hereinafter, sometimes abbreviated as "Q 12 ​​​​​​​​​​​​​​​​​​​​​​​​​​​​It is sometimes abbreviated as "). )) was isolated as a colorless solid (powder) with a yield of 90% (0.170g). Note that Q 12 H 12 When the colorless solid (powder) was dissolved in deuterated DMSO-d6 and the NMR was measured, 1 7.07 ppm by H-NMR. 29 A peak was observed at -101.2 ppm in Si-NMR. Also, Q 12 H 12 The colorless solid (powder) was dissolved in a mixed solvent of dimethyl sulfoxide and acetonitrile, and high-resolution mass spectrometry (TOF-MS) was performed, yielding the theoretical value: H 12 O 30 Si 12 The measured value was 850.6538 compared to 850.6537 for Na[M+Na]. Based on various NMR and high-resolution mass spectrometry results, the product obtained in Example 1 has a Q structure represented by the following formula (1). 12 H 12 I confirmed that this is the case. Q 12 H 12 It was found that it can maintain a stable state as a standalone powder (100% purity). [ka]

[0061] [Example 2] Q 12 H 12 synthesis Q 12 K 12 A dispersion of 2αCD·59,3H2O, 6.845 g (1.602 mmol), was suspended in 80 mL of THF (reaction solvent). 3.924 mL (46.99 mmol) of hydrochloric acid was added to this dispersion, and the mixture was stirred for 15 minutes to obtain a suspension. This suspension was filtered to obtain the filtrate. 80 mL of ethyl acetate (poor solvent) was added to the obtained filtrate and stirred for 60 minutes to reprecipitation (precipitate the solid). The suspension solution was filtered to separate the solid. After collecting the solid, it was dried under reduced pressure to obtain Q 12 H 12 It was isolated as a colorless solid (powder) with a yield of 74% (1.167 g).

[0062] [Example 3] Q 12 H 12 synthesis Q 12 K 12 A dispersion of 2αCD·59,3H2O, 6.886 g (1.602 mmol), was suspended in 80 mL of THF (reaction solvent). 3.007 mL (47.44 mmol) of nitric acid was added to this dispersion, and the mixture was stirred for 15 minutes to obtain a suspension. This suspension was filtered to obtain the filtrate. 80 mL of ethyl acetate (poor solvent) was added to the obtained filtrate and stirred for 60 minutes to reprecipitation (precipitate the solid). The suspension solution was filtered to separate the solid. After collecting the solid, it was dried under reduced pressure to obtain Q 12 H 12 It was isolated as a colorless solid (powder) with a yield of 14% (0.215 g). [Industrial applicability]

[0063] The silanol compound of this embodiment can maintain a stable state as a powder on its own (for example, with a purity of 100%), making it easy to handle, extremely advantageous in material development, and potentially applicable to industry.

Claims

1. A silanol compound represented by the following formula (1). 【Chemistry 1】

2. A composition comprising the silanol compound described in claim 1.

3. The composition according to claim 2, wherein the content of the silanol compound is 0.1 to 99.9% by mass.

4. The composition according to claim 2 or 3, further comprising at least one selected from the group consisting of water, ether compounds, amine compounds, amide compounds, ammonium salts, and metal complexes.

5. A method for producing a silanol compound, comprising a proton exchange step of reacting a silicate having the structure represented by the following formula (1)' with an acidic compound to obtain a solution containing a silanol compound represented by the following formula (1). 【Chemistry 2】 (In formula (1)', Q ＋ (This represents a positive ion.) 【Transformation 3】

6. A method for producing a silanol compound according to claim 5, further comprising the steps of adding a poor solvent for precipitating the silanol compound represented by formula (1) to the solution obtained in the proton exchange step, precipitating the silanol compound represented by formula (1), and isolating the silanol compound represented by formula (1) as a powder.

7. A method for producing a silanol compound according to claim 5 or 6, wherein the acid dissociation constant pKa of the acidic compound in dimethyl sulfoxide (DMSO) is -1 to 20.

8. A method for producing a silanol compound according to any one of claims 5 to 7, wherein the acid dissociation constant pKa of the acidic compound in dimethyl sulfoxide (DMSO) is 12.6 or less.

9. A method for producing a silanol compound according to any one of claims 5 to 8, wherein the acidic compound is an inorganic acid.

10. The method for producing a silanol compound according to claim 9, wherein the inorganic acid is hydrochloric acid or nitric acid.

11. The method for producing a silanol compound according to claim 9, wherein the inorganic acid is hydrochloric acid.

12. A method for producing a silanol compound according to any one of claims 5 to 8, wherein the acidic compound is at least one selected from the group consisting of acetic acid and compounds having a structure represented by the following formulas (b-1) to (b-5). 【Chemistry 4】 (In formulas (b-1) to (b-5), X is independently an oxygen atom, a sulfur atom, or an amino group (-NR ３ -) to, R １ R is a hydrogen atom or a hydrocarbon group having 1 to 14 carbon atoms. ２ Each of these independently represents a hydrogen atom or a hydrocarbon group having 1 to 14 carbon atoms.

13. The method for producing a silanol compound according to claim 12, wherein the acidic compound is a resin having at least one structure selected from the group consisting of structures represented by formulas (b-2) to (b-5).

14. A method for producing a silanol compound according to any one of claims 5 to 13, wherein the proton exchange step is carried out in at least one liquid selected from the group consisting of water, ether-based liquids, alcohol-based liquids, amide-based liquids, ester-based liquids, halogen-based liquids, and aprotic polar liquids.

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