Method for producing alkanedisulfonic acid compounds

Abstract

Provided is an industrially advantageous method which is for producing an alkane disulfonic acid compound and by which an alkane disulfonic acid compound can be easily and inexpensively produced at high yield.　The present invention is a method for producing an alkane disulfonic acid compound, the method comprising a step for obtaining an alkane disulfonic acid compound by reacting at least one alkane sulfonic acid compound having a specific structure with at least one complex having a Lewis base and sulfur trioxide. According to this production method, an alkane disulfonic acid compound can be easily and inexpensively produced at high yield, which is industrially advantageous.

Description

[Technical field]

[0001] The present invention relates to a method for producing an alkanedisulfonic acid compound. [Background technology]

[0002] It has been known that alkanedisulfonic acid compounds are useful not only as pharmaceuticals such as leukemia treatment drugs for animals, but also as raw materials for functional materials such as stabilizers for electrolytes for secondary batteries, and thus they can be said to be highly valuable compounds. It is known that such alkanedisulfonic acid compounds can be produced by various methods.

[0003] For example, Patent Document 1 discloses a method for obtaining a methane disulfonic acid compound by treating methane and sulfur trioxide with mercuric sulfate under an atmosphere of 5.8 MPa and 260° C. for 1.5 hours. Patent Document 2 discloses a method for obtaining methane disulfonic acid by reacting methanesulfonic acid with sulfur trioxide. Patent Document 3 discloses a method for obtaining methane disulfonic acid by reacting dibromomethane with a sulfite in the presence of tetrabutylammonium bromide and potassium iodide to obtain a methanesulfonate salt, and then obtaining methane disulfonic acid using an ion exchange resin. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 2493038 [Patent Document 2] U.S. Patent No. 2842589 [Patent Document 3] US Patent Application Publication No. 2006 / 0155142 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the method disclosed in Patent Document 1 requires the use of a toxic mercury compound and reaction conditions such as high temperature and high pressure, and is not necessarily suitable for industrial production. In addition, the method disclosed in Patent Document 2 has a problem that the yield of methane disulfonic acid is low, which is disadvantageous for industrial production. Furthermore, the method disclosed in Patent Document 3 enables the reaction under atmospheric pressure, but the process is complicated, and the catalyst remains as an impurity and a large amount of ion exchange resin is required, making it difficult to carry out on an industrial scale.

[0006] The present invention has been made in view of the above, and an object of the present invention is to provide an industrially advantageous method for producing an alkanedisulfonic acid compound, which can produce an alkanedisulfonic acid compound in high yield, easily and inexpensively. [Means for solving the problem]

[0007] As a result of intensive research into achieving the above-mentioned object, the inventors have found that the above-mentioned object can be achieved by reacting a specific alkanesulfonic acid compound with a complex having a Lewis base and sulfur trioxide, and have thus completed the present invention.

[0008] That is, the present invention includes, for example, the subject matter described in the following sections. Item 1 A method for producing an alkanedisulfonic acid compound, comprising the steps of: at least one alkane sulfonic acid compound; At least one complex having a Lewis base and sulfur trioxide; to obtain an alkane disulfonic acid compound, The alkanesulfonic acid compound is represented by the following general formula (1):

[0009] [ka]

[0010] (In formula (1), R 1and R 2 are the same or different and each represents an alkyl group having 1 to 4 carbon atoms which may be substituted by a halogen atom or a hydrogen atom; n represents an integer of 1 to 4; when n is an integer of 2 to 4, n R 1 may be the same or different, and n R 2 may be the same or different.) A compound represented by the formula: The alkane disulfonic acid compound is represented by the following general formula (4):

[0011] [ka]

[0012] (In formula (4), R 1 , R 2 and n are each R in formula (1). 1 , R 2 and n.) A method for producing an alkanedisulfonic acid compound represented by the formula: Section 2 The Lewis base comprises a sulfoxide compound; The sulfoxide compound is represented by the following general formula (2):

[0013] [ka]

[0014] (In formula (2), R 3 and R 4 are the same or different and each represents an alkyl group having 1 to 12 carbon atoms which may have a substituent, R 3 and R 4 may be bonded to each other together with the sulfur atom to which they are bonded, with or without a heteroatom to form a cyclic structure. Item 3. The method according to item 1, wherein the compound is represented by the formula: Section 3 The Lewis base comprises a sulfone compound, The sulfone compound is represented by the following general formula (3):

[0015] [ka]

[0016] (In formula (3), R 3 and R 4 are the same or different and each represents an alkyl group having 1 to 12 carbon atoms which may have a substituent; R 3 and R 4 may be bonded to each other together with the sulfur atom to which they are attached to form a cyclic structure with or without a heteroatom. Item 3. The method according to item 1 or 2, wherein the compound is represented by the formula: Section 4 Item 3. The method according to Item 2, wherein the sulfoxide compound is dimethyl sulfoxide. Section 5 Item 4. The method according to item 3, wherein the sulfone compound is at least one selected from the group consisting of sulfolane, 3-methylsulfolane, ethyl methyl sulfone, and ethyl isopropyl sulfone. Effect of the Invention

[0017] According to the production method of the present invention, it is possible to produce an alkanedisulfonic acid compound in high yield, easily and inexpensively, and is industrially advantageous. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, embodiments of the present invention will be described in detail. In this specification, the term "comprising" includes "consisting essentially of" and "consisting of."

[0019] In the numerical ranges described in stages in this specification, the upper or lower limit of a certain numerical range can be arbitrarily combined with the upper or lower limit of another numerical range. In the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in an example or a value that can be unambiguously derived from an example. In addition, in this specification, a numerical value connected with "~" means a numerical range that includes the numerical values ​​before and after "~" as the lower and upper limits.

[0020] The method for producing an alkanedisulfonic acid compound of the present invention includes a step of reacting at least one alkanedisulfonic acid compound with at least one complex having a Lewis base and sulfur trioxide to obtain an alkanedisulfonic acid compound, which will hereinafter be referred to as "Step A."

[0021] (Alkanesulfonic acid compounds) The alkanesulfonic acid compound used in step A is a compound represented by the following general formula (1).

[0022] [ka]

[0023] Here, in formula (1), R 1 and R 2 are the same or different and each represents an alkyl group having 1 to 4 carbon atoms which may be substituted with a halogen atom or a hydrogen atom, and n represents an integer of 1 to 4. In formula (1), when n is an integer of 2 to 4, n R 1 may be the same or different. When n is an integer of 2 to 4, n R 2 may be the same or different.

[0024] R in Equation (1) 1 and R 2In the above, the type of the alkyl group having 1 to 4 carbon atoms which may be substituted with a halogen atom is not particularly limited. Examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom. Specific examples of the alkyl group having 1 to 4 carbon atoms which may be substituted with a halogen atom include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, a fluoromethyl group, a trifluoromethyl group, a chloromethyl group, a chloroethyl group, a chloropropyl group, and a bromomethyl group.

[0025] In formula (1), R 1 R is preferably a hydrogen atom, a methyl group, an ethyl group, or an n-propyl group, and more preferably a hydrogen atom. 2 is preferably a hydrogen atom, a methyl group, an ethyl group, or an n-propyl group, and more preferably a hydrogen atom. 1 and R 2 are preferably the same.

[0026] In formula (1), when n is an integer of 2 to 4, that is, when n is 2, 3, or 4, n R 1 may be the same or different, and similarly, n R 2 In formula (1), when n is an integer of 2 to 4, n R 1 are preferably all the same, and when n is an integer of 2 to 4, n R 2 are preferably all the same.

[0027] In the formula (1), n ​​is particularly preferably 1, in which case the yield of the target alkanedisulfonic acid compound tends to be particularly high.

[0028] The alkane sulfonic acid compound is not particularly limited as long as it is a compound represented by formula (1). Preferably, the alkane sulfonic acid compound is methanesulfonic acid (in formula (1), R 1 =R 2=H, n=1), ethanesulfonic acid (in formula (1), R 1 =CH3, R 2 =H, n=1), 1-propanesulfonic acid (in formula (1), R 1 =CH2CH3,R 2 =H, n=1), 2-propanesulfonic acid (in formula (1), R 1 =R 2 =CH3, n=1), 1-butanesulfonic acid (in formula (1), R 1 =R 2 =H, n=4), etc.

[0029] The alkane sulfonic acid compound used in step A can be obtained from a commercial product, or can be obtained by a known method or a method easily derived from a known method. For example, the alkane sulfonic acid compound can be synthesized by a method of oxidizing a corresponding disulfide compound using methyltrioxorhenium(VII) / hydrogen peroxide as a catalyst, with reference to Tetrahedron Letters (2009), 50(46), 6231-6232. Alternatively, the alkane sulfonic acid compound can be synthesized by a method of oxidizing a corresponding thiol compound using hydrogen peroxide, with reference to International Publication No. WO 2004 / 058693.

[0030] The alkanesulfonic acid compound used in step A may be one type alone or two or more types in combination.

[0031] (Complexes with Lewis bases and sulfur trioxide) In step A, at least one type of complex is used. Such a complex has a Lewis base and sulfur trioxide (SO3). The complex used in step A may have a structure in which, for example, a Lewis base and sulfur trioxide are coordinated. In this case, for example, a complex is formed by one molecule of Lewis base and one molecule of sulfur trioxide. Alternatively, two or more molecules of Lewis base may be coordinated to one molecule of sulfur trioxide, and in this case, the two or more molecules of Lewis base may all be different types, or some or all of them may be the same type.

[0032] In the complex, the type of Lewis base is not particularly limited as long as it can form a complex with sulfur trioxide. For example, the Lewis base can be a compound capable of forming a coordinate bond with sulfur trioxide, and among them, from the viewpoint of easy coordination with sulfur trioxide, the Lewis base is preferably a compound having an S=O bond. Examples of such Lewis bases include sulfoxide compounds and sulfone compounds.

[0033] Therefore, the complex used in step A may include a complex having a sulfoxide compound and sulfur trioxide. Alternatively, the complex used in step A may include a complex having a sulfone compound and sulfur trioxide. The sulfoxide compound and the sulfone compound are described below.

[0034] An example of the sulfoxide compound is a compound represented by the following general formula (2).

[0035] [ka]

[0036] Here, in formula (2), R 3 and R 4 are the same or different and each represents an alkyl group having 1 to 12 carbon atoms which may have a substituent. In formula (2), R 3 and R 4 may be bonded to each other together with the sulfur atom to which they are attached to form a cyclic structure with or without a heteroatom.

[0037] Moreover, the sulfone compound may, for example, be a compound represented by the following general formula (3).

[0038] [ka]

[0039] Here, in formula (3), R 3and R 4 are the same or different and each represents an alkyl group having 1 to 12 carbon atoms which may have a substituent; R 3 and R 4 may be bonded to each other together with the sulfur atom to which they are bonded, with or without a heteroatom to form a cyclic structure. 3 and R 4 is R in Eq. (2). 3 and R 4 is synonymous with.

[0040] R in formula (2) and formula (3) 3 and R 4 In the formula (I), when the alkyl group having 1 to 12 carbon atoms has a substituent, the type of the substituent is not particularly limited. Specific examples of the substituent include a halogen atom, an alkoxy group, a carboxyl group, a cyano group, a nitro group, and a sulfo group.

[0041] R in formula (2) and formula (3) 3 and R 4 In the above, examples of the alkyl group having 1 to 12 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-hexyl group, an n-octyl group, an n-decyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, a norbornyl group, an adamantyl group, a cyclopentylmethyl group, a cyclohexylmethyl group, and a 2-cyclohexylethyl group. These alkyl groups may also have the above-mentioned substituent. The number of carbon atoms is preferably 1 to 6, in that the yield of the target alkanedisulfonic acid compound is likely to be high. Therefore, among the above-listed examples of the alkyl group having 1 to 12 carbon atoms, a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-hexyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, or a cyclopentylmethyl group is preferred.

[0042] In formula (2) and formula (3), R 3 and R 4 and may be bonded together with the sulfur atom to which they are bonded to form a cyclic structure with or without a heteroatom. That is, they may form a cyclic structure containing the sulfur atom in the compounds represented by formulas (2) and (3) as a ring member. In this case, for example, R 3 and R 4 The carbon atoms of R can form chemical bonds to form a ring structure. For example, R 3 and R 4 A cyclic structure can be formed together with the sulfur atom by a covalent bond between the terminal carbon atoms of the ring. The cyclic structure is, for example, a saturated ring containing a sulfur atom. When the cyclic structure has a hetero atom in addition to the sulfur atom, the type of the hetero atom is not particularly limited.

[0043] Specific examples of the sulfoxide compound represented by formula (2) include dimethyl sulfoxide, ethyl methyl sulfoxide, methyl n-propyl sulfoxide, dipropyl sulfoxide, dibutyl sulfoxide, di-n-octyl sulfoxide, didodecyl sulfoxide, and tetramethylene sulfoxide. Among these, the sulfoxide compound represented by formula (2) is preferably dimethyl sulfoxide.

[0044] Specific examples of the sulfone compound represented by formula (3) include trimethylene sulfone, hexamethylene sulfone, trimethylene disulfone, tetramethylene disulfone, hexamethylene disulfone, sulfolane, 3-methyl sulfolane, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, methyl n-propyl sulfone, ethyl n-propyl sulfone, di-n-propyl sulfone, methyl isopropyl sulfone, ethyl isopropyl sulfone, diisopropyl sulfone, n-butyl methyl sulfone, n-butyl ethyl sulfone, t-butyl methyl sulfone, t-butyl ethyl sulfone, etc. Among these, the sulfone compound represented by formula (3) is preferably sulfolane, 3-methyl sulfolane, ethyl methyl sulfone, or ethyl isopropyl sulfone, more preferably sulfolane or 3-methyl sulfolane, and even more preferably sulfolane.

[0045] A preferred complex used in step A is at least one selected from the group consisting of a complex having a sulfoxide compound and sulfur trioxide represented by formula (2) and a complex having a sulfone compound and sulfur trioxide represented by formula (3), in that it tends to increase the yield of the target product. More specifically, the Lewis base constituting the complex used in step A is preferably at least one selected from the group consisting of dimethyl sulfoxide, sulfolane, 3-methyl sulfolane, ethyl methyl sulfone, and ethyl isopropyl sulfone, more preferably at least one selected from the group consisting of sulfolane, 3-methyl sulfolane, ethyl methyl sulfone, and ethyl isopropyl sulfone, and particularly preferably sulfolane.

[0046] The complex used in step A may be one type alone, or two or more different types may be used. For example, the complex used in step A may be only one type of complex having the sulfoxide compound and sulfur trioxide, or two or more types of complexes having the sulfoxide compound and sulfur trioxide may be used in combination. Similarly, the complex used in step A may be only one type of complex having the sulfone compound and sulfur trioxide, or two or more types of complexes having the sulfone compound and sulfur trioxide may be used in combination. In addition, the complex used in step A may include both a complex having a sulfoxide compound and sulfur trioxide and a complex having a sulfone compound and sulfur trioxide.

[0047] The complex used in step A can be obtained from commercial products or can be synthesized with reference to known methods. For example, a complex in which sulfolane is coordinated with sulfur trioxide can be synthesized with reference to Journal of Applied Chemistry and Biotechnology. 1976, 26, 513-516.

[0048] As an example of a method for producing the complex, the complex can be obtained by a step of mixing a Lewis base (for example, a sulfoxide compound represented by formula (2) or a sulfone compound represented by formula (3)) with sulfur trioxide. Hereinafter, this step will be referred to as a "mixing step". In the mixing step, the mixing ratio of the Lewis base to sulfur trioxide is not particularly limited. For example, in terms of facilitating the formation of a complex and increasing the yield, the Lewis base is preferably 0.1 to 10 mol, more preferably 0.2 to 8 mol, and even more preferably 0.3 to 6 mol relative to 1 mol of sulfur trioxide.

[0049] When the Lewis base and sulfur trioxide are mixed in the mixing step, the temperature during mixing can be, for example, 0 to 100°C. In addition, when mixing the two, a method of dropping one into the other can also be adopted. After mixing, for example, the complex is obtained as white crystals, and the complex can be obtained by extracting the white crystals by an appropriate method. In particular, when sulfolane is used as the Lewis base, it is preferable to obtain the complex by a production method including the mixing step. The presence or absence of the complex can be determined, for example, by 1 This can be determined from the H-NMR spectrum.

[0050] When the complex used in step A is obtained by separate synthesis, such a complex can be synthesized in advance prior to the reaction of the alkanesulfonic acid compound with the complex in step A, and the complex can be isolated and used in the reaction in step A. Alternatively, the previously synthesized complex does not necessarily need to be isolated, and the reactant obtained in the synthesis of the complex can be used as it is in the reaction in step A.

[0051] (Reaction in Step A) In step A, the at least one alkanesulfonic acid compound is reacted with the at least one complex.

[0052] The amount of the complex used in the reaction of step A is preferably 0.1 mol or more, more preferably 0.2 mol or more, and even more preferably 0.3 mol or more relative to 1 mol of the alkane sulfonic acid compound, in terms of the tendency to increase the yield of the target alkane disulfonic acid compound. The amount of the complex used in the reaction of step A is preferably 10 mol or less, more preferably 8 mol or less, and even more preferably 6 mol or less relative to 1 mol of the alkane sulfonic acid compound, in terms of being more economical. Here, "1 mol of the alkane sulfonic acid compound" means that when two or more kinds of alkane sulfonic acid compounds are used, the total amount of them is 1 mol.

[0053] In the reaction of step A, for example, a raw material A containing the alkane sulfonic acid compound and the complex is placed in a reaction vessel, and the reaction can be carried out in the reaction vessel. In this case, the raw material A can also be dissolved or dispersed in a solvent as necessary. When a solvent is used, the amount of the solvent used is not particularly limited, and can be, for example, 1500 parts by mass or less, and preferably 1000 parts by mass or less, relative to 100 parts by mass of the total amount of the alkane sulfonic acid compound.

[0054] When dissolving or dispersing the raw material A in a solvent, the solvent that can be used can be appropriately selected within a range that does not impair the effects of the present invention. Examples of such solvents include hydrocarbon solvents, halogen solvents, ether solvents, ketone solvents, ester solvents, amide solvents, nitrile solvents, sulfoxide solvents, sulfone solvents, and sulfuric acid. Examples of hydrocarbon solvents include toluene, xylene, monochlorobenzene, dichlorobenzene, trichlorobenzene, hexane, heptane, and decane. Examples of halogen solvents include dichloromethane and 1,2-dichloroethane. Examples of ether solvents include diethyl ether, ethylene glycol dimethyl ether, diisopropyl ether, diphenyl ether, tetrahydrofuran, dioxane, methyl-tert-butyl ether, and cyclopentyl methyl ether. Examples of ketone solvents include acetone, methyl ethyl ketone, and methyl isobutyl ketone. Examples of ester solvents include ethyl acetate and butyl acetate. Examples of amide solvents include dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. Examples of nitrile solvents include acetonitrile. Examples of sulfoxide solvents include dimethylsulfoxide. Examples of sulfone solvents include ethyl methyl sulfone, ethyl isopropyl sulfone, sulfolane, and 3-methylsulfolane.

[0055] Furthermore, when the complex is synthesized by the reaction of a Lewis base with sulfur trioxide as described above, the Lewis base may be used in excess relative to the sulfur trioxide, and the remaining free Lewis base that does not form a complex with sulfur trioxide may be used substantially as a solvent in the reaction of step A. Thus, when an excess amount of Lewis base is reacted with sulfur trioxide to synthesize a complex, the resulting complex can be directly used as the complex to be used in the reaction of step A without producing a reactant, and the remaining Lewis base can play the role of a solvent in the reaction of step A. In particular, when an excess amount of sulfolane is used as the Lewis base, it is preferable that the remaining sulfolane also serves as a solvent for the reaction of step A.

[0056] The raw material A used in the step A may contain other additives in addition to the solvent, or may consist only of the alkane sulfonic acid compound and the complex, or may consist only of the alkane sulfonic acid compound, the complex, and the solvent.

[0057] The type of reaction vessel used in the reaction of step A is not particularly limited, and for example, a wide variety of known reaction vessels can be used.

[0058] The reaction conditions in step A are not particularly limited. For example, the reaction temperature in step A is not particularly limited and can be appropriately set depending on the conditions such as the type of raw material and the amount of raw material. For example, the reaction temperature can be 0 to 200°C, and is preferably 50 to 180°C, more preferably 80 to 170°C, and even more preferably 100 to 160°C, in that the yield of the target product is likely to be high. The reaction time can be appropriately set depending on the reaction temperature, and can be, for example, about 1 to 48 hours.

[0059] In the reaction of step A, the method for adjusting the reaction temperature is not particularly limited. For example, the reaction temperature can be set to an appropriate temperature by heating the reaction vessel in which the raw material A is placed.

[0060] The reaction can be carried out while stirring the raw material A with a stirrer or the like. The reaction can also be carried out by charging all the raw materials in a reaction vessel in random order and maintaining the temperature at a predetermined level. Alternatively, the reaction can be carried out while adding any of the raw materials dropwise.

[0061] The reaction in step A can be carried out under any of increased pressure, reduced pressure, and atmospheric pressure. The reaction in step A can also be carried out in an inert gas atmosphere such as nitrogen or argon. The reaction can also be carried out while blowing in an inert gas.

[0062] The target alkane disulfonic acid compound is produced by the reaction in step A. This alkane disulfonic acid compound is a compound represented by the following general formula (4).

[0063] [ka]

[0064] Here, in formula (4), R 1 , R 2 and n are each R in formula (1). 1 , R 2 and n.

[0065] Specific examples of the alkane disulfonic acid compound represented by formula (4) include methane disulfonic acid (R 1 =R 2 =H, n=1), ethanedisulfonic acid (R 1 =CH3, R 2 =H, n=1), 1-propanedisulfonic acid (R 1 =CH2CH3,R 2 =H, n=1), 2-propanedisulfonic acid (R 1 =R 2 =CH3, n=1), 1-butanedisulfonic acid (R 1 =R 2 =H, n=4) and the like.

[0066] The alkane disulfonic acid compound obtained in step A can be isolated by a conventionally known purification operation and isolation operation, and the method is not particularly limited. For example, the alkane disulfonic acid compound obtained in step A can be isolated by a method such as extracting the reaction liquid obtained after the reaction in step A using a solvent, washing, and then crystallizing. When the obtained alkane disulfonic acid compound is used as a raw material for another reaction, it is not necessarily necessary to isolate it, and the reaction liquid containing the alkane disulfonic acid compound can be directly used in the subsequent reaction. For example, the alkane disulfonic acid compound obtained in step A can be used as a raw material for producing a methylene disulfonate compound.

[0067] Usually, in the production of an alkanedisulfonic acid compound using sulfur trioxide, the reaction between sulfur trioxide and the alkanedisulfonic acid compound is difficult to occur, and the yield of the alkanedisulfonic acid compound is low. In contrast, when the alkanedisulfonic acid compound is reacted with a Lewis base-sulfur trioxide (SO3) complex (e.g., a complex in which a Lewis base is coordinated to SO3) as in step A, the sulfur trioxide in the complex reacts efficiently with the alkanedisulfonic acid compound, and the yield of the produced alkanedisulfonic acid compound is improved.

[0068] The present disclosure includes all arbitrary combinations of the constituent features described in this specification. In addition, the various characteristics (properties, structures, functions, etc.) described for each embodiment of the present disclosure above may be combined in any way to specify the subject matter included in the present disclosure. In other words, the present disclosure includes all subject matter consisting of all combinations of each combinable characteristic described in this specification. EXAMPLES

[0069] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the embodiments of these examples.

[0070] [Production Example 1] A four-neck flask equipped with a stirrer, a condenser, a thermometer, and a dropping funnel was charged with 36.1 g (0.30 mol) of sulfolane as a Lewis base, and 12.0 g (0.15 mol) of sulfur trioxide was added dropwise thereto over 30 minutes to obtain a mixed solution, which was then heated to 60°C and stirred at this temperature for 30 minutes. The resulting reaction solution was cooled to 20°C and stirred for 1 hour, after which the precipitated white crystals were filtered out in a dry nitrogen atmosphere and washed with dichloromethane. The resulting wet body was dried in a dry nitrogen atmosphere to obtain 20.1 g (0.10 mol) of a complex consisting of a Lewis base and sulfur trioxide. This complex is a sulfolane-sulfur trioxide complex, as shown below. 1 This was determined from the results of H-NMR analysis. 1 H-NMR (400MHz, CDCl3)δ(ppm):2.28(4H),3.17(4H) For comparison, the free sulfolane 1 The results of H-NMR analysis are as follows: 1 H-NMR (400 MHz, CDCl3) δ (ppm): 2.23 (4H), 3.04 (4H).

[0071] Example 1 A four-neck flask equipped with a stirrer, a cooling tube, a thermometer, and a dropping funnel was charged with 40.1 g (0.20 mol) of the sulfolane-sulfur trioxide complex obtained in Production Example 1 and 19.2 g (0.20 mol) of methanesulfonic acid as raw material A. The raw material A in the flask was heated to 150°C while being stirred, and the reaction was continued at this temperature for 5 hours to obtain a reaction liquid. An appropriate amount of the reaction liquid obtained was sampled and analyzed by ion chromatography, and based on the area value of the peak obtained in this analysis, the product methanedisulfonic acid (R 1 and R 2 The production yield of the compound (wherein n is a hydrogen atom and n is 1) was calculated. As a result, the production yield of the obtained methanedisulfonic acid was 75 mol %.

[0072] Example 2 In the preparation of raw material A, methane disulfonic acid (R 1 and R 2 A compound in which n is a hydrogen atom and n is 1 was produced, and the production yield was calculated. As a result, the production yield of the obtained methanedisulfonic acid was 82 mol %.

[0073] Comparative Example 1 Raw materials consisting of 19.2 g (0.20 mol) of methanesulfonic acid and 16.0 g (0.20 mol) of sulfur trioxide were charged into a four-neck flask equipped with a stirrer, a cooling tube, a thermometer, and a dropping funnel. The raw materials in the flask were heated to 150°C while being stirred, and the reaction was continued at this temperature for 5 hours to obtain a reaction liquid. An appropriate amount of the reaction liquid obtained was sampled and analyzed by ion chromatography, and based on the area value of the peak obtained in this analysis, the product methane disulfonic acid (R 1 and R 2 The production yield of the compound (wherein n is a hydrogen atom and n is 1) was calculated. As a result, the production yield of the obtained methanedisulfonic acid was 40 mol %.

[0074] From the above results, it was found that the production methods performed in the respective Examples can smoothly proceed with the reaction by including step A, and can obtain the target product, methanedisulfonic acid, represented by formula (4), in high production yield. That is, it was demonstrated that the production method according to the present invention can easily and inexpensively produce an alkanedisulfonic acid compound in high yield, and is industrially advantageous.

Claims

1. A method for producing an alkanedisulfonic acid compound, comprising the steps of: at least one alkane sulfonic acid compound; At least one complex having a Lewis base and sulfur trioxide; to obtain an alkane disulfonic acid compound, The alkanesulfonic acid compound is represented by the following general formula (1): 【Chemistry 1】 (In formula (1), R １ and R ２ are the same or different and each represents an alkyl group having 1 to 4 carbon atoms which may be substituted by a halogen atom or a hydrogen atom; n represents an integer of 1 to 4; when n is an integer of 2 to 4, n R １ may be the same or different, and n R ２ may be the same or different.) A compound represented by the formula: The Lewis base comprises a sulfone compound, The sulfone compound is represented by the following general formula (3): 【Chemistry 2】 (In formula (3), R 3 and R 4 are the same or different and each represents an alkyl group having 1 to 6 carbon atoms which may have a substituent, and R 3 and R 4 may be bonded to each other together with the sulfur atom to which they are bonded, with or without a heteroatom, to form a cyclic structure.) A compound represented by the formula: The alkanedisulfonic acid compound is represented by the following general formula (4): 【Chemistry 3】 (In formula (4), R １ , R ２ and n are each R in formula (1). １ , R ２ and n.) The present invention relates to a method for producing an alkanedisulfonic acid compound represented by the following formula:

2. The method according to claim 1, wherein the sulfone compound is at least one selected from the group consisting of sulfolane, 3-methylsulfolane, ethyl methyl sulfone, and ethyl isopropyl sulfone.

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