Method for producing methylene disulfonate compounds

Abstract

Provided is a novel method that enables a methylene disulfonate compound to be easily produced.　The method for producing a methylene disulfonate compound includes reacting a specific sulfonic acid compound with a formaldehyde compound in the presence of sulfur trioxide.

Description

[Technical field]

[0001] The present disclosure relates to a method for producing a methylene disulfonate compound, etc. The contents of all documents described in this specification are incorporated herein by reference. [Background technology]

[0002] Methylene disulfonate compounds are known to be useful as pharmaceuticals such as drugs for treating leukemia in animals, and as stabilizers for electrolytes for secondary batteries.

[0003] For example, Patent Document 1 discloses a method for producing a methylene disulfonate compound by reacting silver disulfonate obtained by reacting disulfonyl chloride with silver carbonate with diiodomethane.

[0004] [ka]

[0005] Furthermore, for example, Patent Document 2 discloses a method for producing a methylene disulfonate compound by reacting an alkane disulfonic acid or the like with methylene diacetate or the like.

[0006] [ka]

[0007] Furthermore, for example, Patent Document 3 discloses a method for producing a methylene disulfonate compound by converting methane disulfonic acid into methane disulfonyl chloride using a chlorinating agent such as thionyl chloride, and reacting this with formaldehyde. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Special Publication No. 61-501089 [Patent Document 2] JP 2005-336155 A [Patent Document 3] China Patent Application Publication No. 102344436 Summary of the Invention [Problem to be solved by the invention]

[0009] However, in the method of Patent Document 1, the silver carbonate and diiodomethane used are expensive, the reaction proceeds slowly, and the target product may not be obtained in a satisfactory yield. In addition, poorly soluble silver iodide is by-produced in a stoichiometric amount, which may cause handling problems in the transfer and filtration steps.

[0010] The method of Patent Document 2 has a problem in that the methylene diacetate used is difficult to obtain and expensive.

[0011] The method of Patent Document 3 involves a multi-step reaction process, which makes the production steps complicated. In addition, there is a problem in that a toxic by-product is generated due to a side reaction caused by the chlorinating agent.

[0012] As described above, none of the conventionally known methods is necessarily satisfactory for implementing mass production on an industrial scale.

[0013] The present inventors have conducted research with the aim of providing a novel method for easily producing a methylene disulfonate compound. Specifically, the present inventors have found the possibility of producing a methylene disulfonate compound by reacting a sulfonic acid compound with a formaldehyde compound in the presence of sulfur trioxide (SO3, also known as sulfuric anhydride), and have made further improvements.

[0014] The present disclosure includes, for example, the subject matter described in the following sections: Item 1 Formula (1):

[0015] [ka]

[0016] (In the formula, two X's are the same or different and each represents a hydrogen atom or an alkali metal. 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. n represents an integer of 1 to 4, and 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.) and Formula (2):

[0017] [ka]

[0018] (In the formula, Y represents an alkaline earth metal. 1 , R 2 , and n are the same as above.) A compound represented by The method comprises reacting at least one sulfonic acid compound selected from the group consisting of: Formula (3):

[0019] [ka]

[0020] (In the formula, R 1 , R 2 and n is as defined above. Section 2 2. The method for producing a methylene disulfonate compound according to claim 1, wherein the formaldehyde compound is at least one selected from the group consisting of paraformaldehyde, anhydrous formaldehyde, trioxane, and methylal. Section 3 Item 3. The method for producing a methylene disulfonate compound according to Item 1 or 2, wherein the sulfonic acid compound is a compound represented by formula (1) in which both of X's are hydrogen atoms. Section 4 Item 4. A method for producing a methylene disulfonate compound according to any one of Items 1 to 3, comprising reacting the sulfonic acid compound with a formaldehyde compound in the presence of sulfur trioxide and a dehydrating agent. Section 5 Item 5. The method for producing a methylene disulfonate compound according to Item 4, wherein the dehydrating agent is phosphorus pentoxide. Effect of the Invention

[0021] The present invention provides a method for easily and inexpensively producing a methylene disulfonate compound, in which the viscosity of the reaction mixture during the process is relatively low and the handling properties are good even in industrial-scale production, and therefore the method is industrially advantageous. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Each embodiment included in the present disclosure will be described in more detail below. The present disclosure preferably includes a method for producing a methylene disulfonate compound, but is not limited thereto, and the present disclosure includes all that is disclosed in the present specification and that can be recognized by a person skilled in the art.

[0023] A method for producing a methylene disulfonate compound encompassed by the present disclosure involves reacting a particular sulfonic acid compound with a formaldehyde compound in the presence of sulfur trioxide.

[0024] The specific sulfonic acid compound is at least one compound selected from the group consisting of compounds represented by formula (1) and compounds represented by formula (2).

[0025] [ka]

[0026] [ka]

[0027] In each of formulas (1) and (2), R 1 and R 2 are each independently (i.e., the same or different) a hydrogen atom or an alkyl group having 1 to 4 carbon atoms (1, 2, 3, or 4) which may be substituted with a halogen atom, and n is an integer of 1 to 4 (1, 2, 3, or 4). In addition, X are the same or different (preferably the same) a hydrogen atom or an alkali metal, and Y is an alkaline earth metal.

[0028] Examples of the halogen atom in the alkyl group having 1 to 4 carbon atoms which may be substituted with a halogen atom include a fluorine atom, a chlorine atom, a bromine atom, etc. 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, a bromomethyl group, etc.

[0029] R 1 and R 2 is preferably a hydrogen atom, a methyl group, an ethyl group, or an n-propyl group, and more preferably a hydrogen atom.

[0030] In each of formulas (1) and (2), when n is an integer of 2 to 4 (2, 3, or 4), n R 1 may be the same or different, and n R 2 may be the same or different. It is preferable that n is 1.

[0031] Examples of the alkali metal represented by X include lithium, sodium, and potassium.

[0032] Examples of the alkaline earth metal represented by Y include magnesium, calcium, and barium.

[0033] The specific sulfonic acid compound is preferably one in which two Xs in formula (1) are the same or different and each is a hydrogen atom, sodium, or potassium, and more preferably one in formula (1) in which two Xs are both hydrogen atoms.

[0034] As specific examples of the sulfonic acid compound represented by formula (1), the following compounds can be preferably mentioned.

[0035] Methanedisulfonic acid (X=H, R 1 =R 2 =H, n=1), 1,1-ethanedisulfonic acid (X=H, R 1 =CH3, R 2 =H, n=1), 1,2-ethanedisulfonic acid (X=H, R 1 =R 2 =H, n=2), 1,1-propanedisulfonic acid (X=H, R 1 =CH2CH3,R 2 =H, n=1), 1,2-propanedisulfonic acid (X=H, R 1 =CH3 and H, R 2 =H, n=2), 1,3-propanedisulfonic acid (X=H, R 1 =R 2 =H, n=3), 2,2-propanedisulfonic acid (X=H, R 1 =R 2 =CH3, n=1), 1,4-butanedisulfonic acid (X=H, R 1 =R 2 =H, n=4), Sodium methane disulfonate (X=Na, R 1 =R 2 = H, n = 1), sodium 1,1-ethanedisulfonate (X = Na, R 1 =CH3, R 2 = H, n = 1), sodium 1,2-ethanedisulfonate (X = Na, R 1 =R 2 = H, n = 2), sodium 1,1-propanedisulfonate (X = Na, R1 =CH2CH3,R 2 = H, n = 1), sodium 1,2-propanedisulfonate (X = Na, R 1 =CH3 and H, R 2 = H, n = 2), sodium 1,3-propanedisulfonate (X = Na, R 1 =R 2 = H, n = 3), sodium 2,2-propanedisulfonate (X = Na, R 1 =R 2 = CH3, n = 1), sodium 1,4-butanedisulfonate (X = Na, R 1 =R 2 =H, n=4), Potassium methanedisulfonate (X=K, R 1 =R 2 = H, n = 1), potassium 1,1-ethanedisulfonate (X = K, R 1 =CH3, R 2 = H, n = 1), potassium 1,2-ethanedisulfonate (X = K, R 1 =R 2 = H, n = 2), potassium 1,1-propanedisulfonate (X = K, R 1 =CH2CH3,R 2 = H, n = 1), potassium 1,2-propanedisulfonate (X = K, R 1 =CH3 and H, R 2 = H, n = 2), potassium 1,3-propanedisulfonate (X = K, R 1 =R 2 = H, n = 3), potassium 2,2-propanedisulfonate (X = K, R 1 =R 2 =CH3, n=1), potassium 1,4-butanedisulfonate (X=K, R 1 =R 2 =H, n=4).

[0036] Specific preferred examples of the sulfonic acid compound represented by formula (2) include the following compounds.

[0037] Calcium methane disulfonate (Y=Ca, R 1 =R 2= H, n = 1), calcium 1,2-ethanedisulfonate (Y = Ca, R 1 =R 2 = H, n = 2), magnesium methane disulfonate (Y = Mg, R 1 =R 2 =H, n=1), barium methanedisulfonate (Y=Ba, R 1 =R 2 = H, n = 1), barium 1,2-ethanedisulfonate (Y = Ba, R 1 =R 2 = H, n = 2), barium 1,2-propanedisulfonate (Y = Ba, R 1 =CH3 and H, R 2 = H, n = 2), barium 1,3-propanedisulfonate (Y = Ba, R 1 =R 2 = H, n = 3), barium 1,4-butanedisulfonate (Y = Ba, R 1 =R 2 =H, n=4).

[0038] The sulfonic acid compound may be a commercially available product, or may be prepared by a known method or a method easily derived from a known method. For example, it may be prepared by reacting a corresponding disulfonyl halide with water, with reference to JP-A-2005-336155. It may be synthesized by reacting dichloromethane with an alkali sulfite in a water solvent at 150 to 160°C, with reference to Recueil des Travaux Chimiques des Pays-Bas, 48, 949-952 (1929).

[0039] The sulfonic acid compounds may be used alone or in combination of two or more.

[0040] As the formaldehyde compound, for example, paraformaldehyde, anhydrous formaldehyde, trioxane, acetalized formaldehyde (e.g., methylal), etc. can be used. Anhydrous formaldehyde can be obtained, for example, by heat-treating paraformaldehyde. Trioxane can be obtained, for example, by acid-treating paraformaldehyde. Among these, as the formaldehyde compound, paraformaldehyde, anhydrous formaldehyde, and trioxane are preferred, and paraformaldehyde is more preferred. The formaldehyde compound can be used alone or in combination of two or more.

[0041] The amount of the formaldehyde compound used can be, for example, 0.6 to 10 mol, preferably 0.7 to 7.0 mol, and more preferably 0.8 to 5.0 mol, per 1.0 mol of the sulfonic acid compound.

[0042] When the amount of the formaldehyde compound used is 0.6 moles or more, the reaction can proceed sufficiently and the yield can be improved, while when the amount is 10 moles or less, it is economical.

[0043] The amount of sulfur trioxide used can be, for example, 0.1 to 10 mol, preferably 0.2 to 8.0 mol, and more preferably 0.3 to 6.0 mol, relative to 1.0 mol of the sulfonic acid compound.

[0044] When the amount of sulfur trioxide used is 0.1 mole or more, the reaction proceeds sufficiently and the yield can be improved, while when the amount is 10 moles or less, it is economical.

[0045] When the specific sulfonic acid compound and the formaldehyde compound are reacted in the presence of sulfur trioxide, a dehydrating agent may be further used to promote the reaction. Examples of the dehydrating agent include phosphorus pentoxide, phosphorus pentachloride, phosphorus oxychloride, thionyl chloride, acetyl chloride, acetic anhydride, and aluminum chloride. Among these, phosphorus pentoxide is preferably used from the viewpoint of reactivity. The dehydrating agent may be used alone or in combination of two or more.

[0046] The amount of the dehydrating agent used may be, for example, 0 to 10 mol, preferably 0 to 5.0 mol, and more preferably 0 to 3.0 mol, relative to 1.0 mol of the sulfonic acid compound. The lower limit of the range is not particularly limited, but may be, for example, about 0.1, 0.5, or 1 mol.

[0047] In the above reaction, a solvent may be used as necessary. The amount of the solvent used may be, for example, 0 to 1500 parts by mass, and preferably 0 to 1000 parts by mass, relative to 100 parts by mass of the sulfonic acid compound. The lower limit of this range is not particularly limited, but may be, for example, about 1, 5, or 10 parts by mass.

[0048] Examples of the solvent include hydrocarbon solvents, ether solvents, ketone solvents, ester solvents, amide solvents, nitrile solvents, sulfoxide solvents, sulfone solvents, and sulfuric acid. Examples of the hydrocarbon solvent include toluene, xylene, monochlorobenzene, dichlorobenzene, trichlorobenzene, hexane, heptane, and decane. Examples of the ether solvent include diethyl ether, ethylene glycol dimethyl ether, diisopropyl ether, diphenyl ether, tetrahydrofuran, dioxane, methyl-tert-butyl ether, and cyclopentyl methyl ether. Examples of the ketone solvent include acetone, methyl ethyl ketone, and methyl isobutyl ketone. Examples of the ester solvent include ethyl acetate and butyl acetate. Examples of the amide solvent include dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. Examples of the nitrile solvent include acetonitrile. Examples of the sulfoxide solvent include dimethyl sulfoxide. Examples of the sulfone solvent include ethyl methyl sulfone, ethyl isopropyl sulfone, sulfolane, and 3-methyl sulfolane. Among these, ether-based solvents, ketone-based solvents, ester-based solvents, amide-based solvents, nitrile-based solvents, sulfoxide-based solvents, sulfone-based solvents, and sulfuric acid are preferred, sulfoxide-based solvents, sulfone-based solvents, and sulfuric acid are more preferred, and sulfoxide-based solvents and sulfone-based solvents are even more preferred.

[0049] In reacting the specific sulfonic acid compound with a formaldehyde compound in the presence of sulfur trioxide, the reaction method is not particularly limited, and examples thereof include a method in which a sulfonic acid compound, sulfur trioxide, and a solvent and a dehydrating agent used as necessary are placed in a reaction vessel, and paraformaldehyde is added while the mixture is sufficiently stirred; a method in which a sulfonic acid compound, a formaldehyde compound, and a solvent and a dehydrating agent used as necessary are placed in a reaction vessel, and sulfur trioxide is added while the mixture is sufficiently stirred; or a method in which a paraformaldehyde compound, sulfur trioxide, and a solvent and a dehydrating agent used as necessary are placed in a reaction vessel, and the sulfonic acid compound is added while the mixture is sufficiently stirred; and the like.

[0050] The reaction temperature can be, for example, about 0 to 200° C., and is preferably about 10 to 150° C. The reaction time may vary depending on the reaction temperature, but is, for example, about 0.1 to 20 hours.

[0051] By the above method, the formula (3):

[0052] [ka]

[0053] (In the formula, R 1 , R 2 and n is the same as above.) can be obtained.

[0054] Specific examples of the methylene disulfonate compound represented by formula (3) include methylenemethane disulfonate (R 1 =R 2 =H, n=1), methylene 1,1-ethane disulfonate (R 1 =CH3, R 2 =H, n=1), methylene 1,2-ethane disulfonate (R 1 =R 2 =H, n=2), methylene 1,1-propane disulfonate (R 1 =CH2CH3,R 2=H, n=1), methylene 1,2-propane disulfonate (R 1 =CH3 and H, R 2 =H, n=2), methylene 1,3-propane disulfonate (R 1 =R 2 =H, n=3), methylene 2,2-propane disulfonate (R 1 =CH3, R 2 =CH3, n=1) and methylene 1,4-butane disulfonate (R 1 =R 2 =H, n=4) and the like.

[0055] The methylene disulfonate compound obtained by the above method can be isolated, for example, by a conventionally known purification and isolation procedure, and the method is not particularly limited, but examples thereof include a method in which the compound is extracted from the reaction mixture using a solvent or the like, and then crystallized through washing with water, etc. Alternatively, for example, water or the like may be added to the reaction mixture to decompose sulfur trioxide, and then crystallized through solvent extraction, washing with water, etc. as described above, or a poor solvent such as water may be added to the reaction mixture to precipitate a crude product, which is then filtered off and purified by recrystallization.

[0056] In addition, in this specification, the term "comprising" includes "consisting essentially of" and "consisting of." In addition, the present disclosure includes all arbitrary combinations of the constituent features described in this specification.

[0057] In addition, the various characteristics (properties, structures, functions, etc.) described in 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

[0058] Hereinafter, the embodiments of the present disclosure will be described more specifically with reference to examples, but the embodiments of the present disclosure are not limited to the following examples.

[0059] [Example 1] In a four-neck flask equipped with a stirrer, a condenser, a thermometer, and a dropping funnel, 17.6 g (0.10 mol) of methane disulfonic acid, 10.0 g of sulfolane, and 16.0 g (0.20 mol) of sulfur trioxide were charged, and 3.3 g of 91% paraformaldehyde (0.10 mol as formaldehyde) was added at room temperature under stirring, and then the mixture was stirred at 55° C. for 3 hours. The production yield of methylene methane disulfonate was 73 mol% based on methane disulfonic acid. The production yield was determined from the peak area value obtained by sampling the reaction solution and analyzing it with HPLC (the same applies to the following examples).

[0060] Next, the reaction mixture was cooled to 25°C. Even at 25°C, the reaction mixture had low viscosity and excellent fluidity.

[0061] Next, methylene chloride and water were added to the reaction mixture, and the organic layer was separated and washed with water. The resulting organic layer was concentrated, and the precipitated crystals were filtered off and dried at 40°C and 10 mmHg for 6 hours to obtain 12.2 g of methylenemethane disulfonate. The yield based on methane disulfonic acid was 65 mol%.

[0062] The crystals were confirmed to be methylenemethane disulfonate by 1H-NMR analysis. 1H-NMR (400MHz, CD3CN) δ (ppm): 5.33 (s, 2H), 6.00 (s, 2H).

[0063] [Example 2] A four-neck flask equipped with a stirrer, a condenser, a thermometer, and a dropping funnel was charged with 17.6 g (0.10 mol) of methane disulfonic acid, 10.0 g of sulfolane, and 16.0 g (0.20 mol) of sulfur trioxide, and 3.3 g of 91% paraformaldehyde (0.10 mol as formaldehyde) was added at room temperature with stirring, followed by stirring for 3 hours at 40° C. The production yield of methylene methane disulfonate was 80 mol% based on methane disulfonic acid.

[0064] Next, the reaction mixture was cooled to 25°C. Even at 25°C, the reaction mixture had low viscosity and excellent fluidity.

[0065] [Example 3] A four-neck flask equipped with a stirrer, a condenser, a thermometer, and a dropping funnel was charged with 17.6 g (0.10 mol) of methane disulfonic acid, 10.0 g of sulfolane, and 16.0 g (0.20 mol) of sulfur trioxide, and 3.3 g of 91% paraformaldehyde (0.10 mol as formaldehyde) was added at room temperature with stirring, followed by stirring for 3 hours at 30° C. The production yield of methylene methane disulfonate was 82 mol% based on methane disulfonic acid.

[0066] Next, the reaction mixture was cooled to 25°C. Even at 25°C, the reaction mixture had low viscosity and excellent fluidity.

[0067] [Example 4] A four-neck flask equipped with a stirrer, a condenser, a thermometer, and a dropping funnel was charged with 17.6 g (0.10 mol) of methane disulfonic acid, 10.0 g of sulfolane, and 24.0 g (0.30 mol) of sulfur trioxide, and 3.3 g of 91% paraformaldehyde (0.10 mol as formaldehyde) was added at room temperature with stirring, followed by stirring for 1 hour at 55° C. The production yield of methylene methane disulfonate was 80 mol% based on methane disulfonic acid.

[0068] Next, the reaction mixture was cooled to 25°C. Even at 25°C, the reaction mixture had low viscosity and excellent fluidity.

[0069] [Example 5] A four-neck flask equipped with a stirrer, a condenser, a thermometer, and a dropping funnel was charged with 17.6 g (0.10 mol) of methane disulfonic acid, 10.0 g of sulfolane, and 27.2 g (0.34 mol) of sulfur trioxide, and 5.6 g of 91% paraformaldehyde (0.17 mol as formaldehyde) was added at room temperature with stirring, followed by stirring for 3 hours at 55° C. The production yield of methylene methane disulfonate was 90 mol% based on methane disulfonic acid.

[0070] Next, the reaction mixture was cooled to 25°C. Even at 25°C, the reaction mixture had low viscosity and excellent fluidity.

[0071] [Example 6] A four-neck flask equipped with a stirrer, a condenser, a thermometer, and a dropping funnel was charged with 17.6 g (0.10 mol) of methane disulfonic acid, 60.0 g of sulfolane, and 38.4 g (0.48 mol) of sulfur trioxide, and 13.2 g of 91% paraformaldehyde (0.40 mol as formaldehyde) was added at room temperature with stirring, followed by stirring for 2 hours at 100° C. The production yield of methylene methane disulfonate was 86 mol% based on methane disulfonic acid.

[0072] Next, the reaction mixture was cooled to 25°C. Even at 25°C, the reaction mixture had low viscosity and excellent fluidity.

[0073] [Example 7] In a four-neck flask equipped with a stirrer, a condenser, a thermometer, and a dropping funnel, 17.6 g (0.10 mol) of methane disulfonic acid, 40.0 g of sulfolane, 19.2 g (0.24 mol) of sulfur trioxide, and 7.1 g of phosphorus pentoxide (0.05 mol as P2O5) were charged, and 6.6 g of 91% paraformaldehyde (0.20 mol as formaldehyde) was added at room temperature with stirring, followed by stirring for 2 hours at 100°C. The production yield of methylene methane disulfonate was 74 mol% based on methane disulfonic acid.

[0074] Next, the reaction mixture was cooled to 25°C. Even at 25°C, the reaction mixture had low viscosity and excellent fluidity.

[0075] [Example 8] A four-neck flask equipped with a stirrer, a condenser, a thermometer, and a dropping funnel was charged with 17.6 g (0.10 mol) of methane disulfonic acid and 24.0 g (0.30 mol) of sulfur trioxide, and 3.3 g of 91% paraformaldehyde (0.10 mol as formaldehyde) was added at room temperature with stirring, followed by stirring for 2 hours at 55° C. The production yield of methylene methane disulfonate was 47 mol% based on methane disulfonic acid.

[0076] Next, the reaction mixture was cooled to 25°C. Even at 25°C, the reaction mixture had low viscosity and excellent fluidity.

[0077] [Example 9] A four-neck flask equipped with a stirrer, a condenser, a thermometer, and a dropping funnel was charged with 17.6 g (0.10 mol) of methane disulfonic acid, 10.0 g of dimethyl sulfoxide, and 24.0 g (0.30 mol) of sulfur trioxide, and 3.3 g of 91% paraformaldehyde (0.10 mol as formaldehyde) was added at room temperature with stirring, followed by stirring for 1 hour at 55° C. The production yield of methylene methane disulfonate was 64 mol% based on methane disulfonic acid.

[0078] Next, the reaction mixture was cooled to 25°C. Even at 25°C, the reaction mixture had low viscosity and excellent fluidity.

[0079] [Example 10] In a four-neck flask equipped with a stirrer, a condenser, a thermometer, and a dropping funnel, 17.6 g (0.10 mol) of methane disulfonic acid, 80.0 g of sulfolane, and 64.1 g of 60% fuming sulfuric acid (sulfuric acid containing 60 mass% sulfur trioxide) (corresponding to 38.4 g or 0.48 mol as sulfur trioxide, and 25.6 g as sulfuric acid) were charged, and 3.3 g of 91% paraformaldehyde (0.10 mol as formaldehyde) was added at room temperature under stirring, and then the mixture was stirred for 1 hour at 55° C. The production yield of methylene methane disulfonate was 69 mol% based on methane disulfonic acid.

[0080] Next, the reaction mixture was cooled to 25°C. Even at 25°C, the reaction mixture had low viscosity and excellent fluidity.

[0081] [Example 11] In a four-neck flask equipped with a stirrer, a condenser, a thermometer, and a dropping funnel, 17.6 g (0.10 mol) of methane disulfonic acid and 40.0 g (corresponding to 24.0 g or 0.30 mol as sulfur trioxide, and 16.0 g as sulfuric acid) of 60% fuming sulfuric acid (sulfuric acid containing 60% by mass of sulfur trioxide) were charged, and 3.3 g of 91% paraformaldehyde (0.10 mol as formaldehyde) was added at room temperature under stirring, and then the mixture was stirred for 1 hour at 55° C. The production yield of methylene methane disulfonate was 47 mol% based on methane disulfonic acid.

[0082] Next, the reaction mixture was cooled to 25°C. Even at 25°C, the reaction mixture had low viscosity and excellent fluidity.

[0083] As can be seen from the above results, the above production method allows the reaction to proceed satisfactorily without the precipitation of by-products or an increase in the viscosity of the reaction mixture that accompanies the progress of the reaction. In other words, it is possible to easily and inexpensively produce a methylene disulfonate compound without poor handling such as poor stirrability during the reaction or an increase in transport load, and is suitable for industrial-scale production.

Claims

1. Formula (1): 【Chemistry 1】 (In the formula, two X's each represent a hydrogen atom. １ and R ２ are the same or different and represent an alkyl group having 1 to 4 carbon atoms which may be substituted with a halogen atom, or a hydrogen atom. n represents an integer of 1 to 4, and 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.) The method includes reacting a sulfonic acid compound represented by the formula: The amount of sulfur trioxide used is 2.0 to 10 moles per 1.0 mole of the sulfonic acid compound. Formula (3): 【Chemistry 2】 (In the formula, R １ , R ２ and n is as defined above.

2. 2. The method for producing a methylene disulfonate compound according to claim 1, wherein the sulfonic acid compound and sulfur trioxide are placed in a reaction vessel, and a formaldehyde compound is added thereto under stirring.

3. 3. The method for producing a methylene disulfonate compound according to claim 1 or 2, wherein the formaldehyde compound is at least one selected from the group consisting of paraformaldehyde, anhydrous formaldehyde, trioxane, and methylal.

4. The method for producing a methylene disulfonate compound according to any one of claims 1 to 3, comprising reacting the sulfonic acid compound with a formaldehyde compound in the presence of sulfur trioxide and a dehydrating agent.

5. The method for producing a methylene disulfonate compound according to claim 4, wherein the dehydrating agent is phosphorus pentoxide.

Images