Method of producing nitromethane

Abstract

The present invention provides a novel method for producing nitromethane. The method for producing nitromethane according to the present invention can provide nitromethane having minimized impurities and a high yield and purity, by controlling the reaction temperature upon carrying out the reaction process.

Description

Method for manufacturing nitromethane

[0001] The present invention relates to a novel method for producing nitromethane.

[0002]

[0003] Nitromethane is a polar liquid commonly used as a solvent in various industrial applications, such as extraction, reaction media, and cleaning solvents. It is widely used as an intermediate in organic synthesis for the manufacture of pharmaceuticals, pesticides, explosives, textiles, and coatings. Additionally, it is used as a fuel (e.g., for racing boats and glow model engines) and is added in small amounts as a volatile liquid to many halogenated solvents and aerosol propellants as a stabilizer. Furthermore, it is used as a polar solvent for some polymers and resins, as a special fuel, and as an explosive.

[0004] Specifically, nitromethane is highly polar and miscible with many organic compounds. Nitromethane is a colorless oily liquid that mixes with alcohols, carbon tetrachloride, dimethylformamide, and other organic solvents and can dissolve aromatic hydrocarbons, but it does not mix with alkanes and cycloalkanes. These selective properties can be used for hydrocarbon separation and lubricating oil purification. Nitromethane and all nitroalkanes readily dissolve anhydrous aluminum chloride and can produce a solution with a content of about 50%.

[0005] To date, many processes, such as the direct nitration of methane, have been proposed for the production of nitromethane. However, because methane is stable, it is much more difficult to nitrate than heavier hydrocarbons. Therefore, research for the synthesis of nitromethane has been conducted using raw materials other than methane.

[0006] In U.S. Patents No. 2,105,581 and 2,117,931, nitroalkanes were produced using a liquid / gas phase system in which a C1-C6 alkyl halide gas passes through an aqueous solution of 1 to 10 moles of sodium nitrite. However, this method did not achieve commercial importance because the reaction rate was very slow.

[0007] In addition, U.S. Patent No. 4,424,385 describes the reaction of an alkali and an alkaline earth metal with a nitrite in the presence of an excess amount of liquid methyl halide to form nitromethane.

[0008] In addition, U.S. Patent No. 4,992,603 ​​proposes a method using a nitrating agent (Nitric acid or NO2) composed of an oxygenated nitrogen compound and a compound containing at least one carbon or two carbons (ethanol, acetic acid, acetaldehyde).

[0009] The process for manufacturing nitroalkanes, particularly nitromethanes, must be a simple process that does not require the cumbersome separation and recovery of catalysts. Furthermore, the desired product must be produced in high condition without using expensive materials to increase the reaction rate.

[0010] Therefore, a new process is required for this.

[0011]

[0012] The present invention aims to produce nitromethane with high yield and purity by minimizing impurities through the control of the reaction temperature during the reaction process.

[0013]

[0014] The present invention comprises the step of preparing a second mixed solution by dropping a first mixed solution containing sodium nitrite (NaNO2), sodium carbonate (Na2CO3), and water onto dimethyl sulfate (DMS) under temperature conditions maintained constant at 5 to 20℃;

[0015] A step of raising the temperature of the second mixed solution to 60 to 80°C by its own reaction heat;

[0016] A step of proceeding the reaction by stirring for 30 minutes or less, and then cooling to 20 to 45°C; and

[0017] A method for producing nitromethane is provided, comprising the step of obtaining nitromethane by vacuum distillation.

[0018]

[0019] In addition, the present invention provides nitromethane produced by the aforementioned method for producing nitromethane.

[0020]

[0021] The method for producing nitromethane according to the present invention can produce nitromethane with high yield and purity while minimizing impurities by controlling the reaction temperature during the reaction process.

[0022] Specifically, in the present invention, when sodium nitrite dissolved in water is dropped onto dimethyl sulfate, the hydrolysis of dimethyl sulfate by water can be minimized. In addition, by maintaining the temperature of the reactor containing dimethyl sulfate at 5 to 20°C, the generation of methyl nitrite, which is an impurity, can be minimized.

[0023] In addition, by maintaining the temperature of the raw materials at 60 to 80°C during the reaction, evaporation caused by the azeotropic mixture of nitromethane and water (NM + H2O azeotrope) phenomenon can be prevented, and the yield reduction can be reduced.

[0024]

[0025] Figure 1 shows the HPLC analysis results of the nitromethane prepared in Example 1.

[0026] Figure 2 shows the NMR analysis results of the nitromethane prepared in Example 1.

[0027] Figure 3 shows the gas chromatography analysis results of the nitromethane prepared in Example 2.

[0028]

[0029] The present invention relates to a method for producing nitromethane.

[0030]

[0031] Hereinafter, a method for manufacturing nitromethane according to the present invention will be described in more detail.

[0032] The method for producing nitromethane according to the present invention comprises the following steps:

[0033] A first step of preparing a second mixed solution by dropping a first mixed solution containing sodium nitrite (NaNO2), sodium carbonate (Na2CO3), and water onto dimethyl sulfate (DMS) under temperature conditions maintained at 5 to 20℃;

[0034] A second step of raising the temperature of the second mixed solution to 60 to 80°C by its own reaction heat;

[0035] A third step of proceeding the reaction by stirring for 30 minutes or less, and then cooling to 20 to 45°C; and

[0036] Step 4, obtaining nitromethane by vacuum distillation.

[0037]

[0038] In the present invention, the first step is to prepare a second mixed solution by dropping a first mixed solution containing sodium nitrite (NaNO2), sodium carbonate (Na2CO3), and water onto dimethyl sulfate (DMS) under temperature conditions maintained at 5 to 20°C.

[0039] Step 1 is a) adding dimethyl sulfate to a reaction vessel and cooling it to 5 to 20°C;

[0040] b) a step of preparing a first mixed solution by dissolving sodium nitrite and sodium carbonate in water in another container; and

[0041] The method may consist of slowly adding the solution prepared in step b) to the solution prepared in step a) at 5 to 20°C.

[0042] In one embodiment, dimethyl sulfate forms nitromethane by methylation in the presence of a base catalyst.

[0043] In one embodiment, sodium nitrite reacts with the dimethyl sulfate to form nitromethane.

[0044] The content of the sodium nitrite above may be 0.7 to 1.1 parts by weight, preferably 0.8 to 1 part by weight, per 1 part by weight of dimethyl sulfate. In addition, the molar ratio of dimethyl sulfate to sodium nitrite may be 1:0.7 to 1:1.2, and preferably 1:0.8 to 1:1.

[0045] In one embodiment, sodium carbonate can be used as a base catalyst.

[0046] Triethylamine, commonly used in the industry as a base catalyst, contains some TEA, and a color change (white to yellow) is observed during simple distillation; NaHCO3 has low reactivity, resulting in a longer reaction time and reduced yield; and NaOH has significantly lower reactivity. In addition, TEAB (tetraethylammonium bromide) and TBAB (tetrabutylammonium bromide), which are PTCs (phase transfer catalysts) widely used alongside base catalysts, have a fast initial reaction, leading to severe gas generation and requiring large quantities due to their large molecular weights; TBAC (tetrabutylammonium chloride) has a low yield; and BEAC (benzyltriethylammonium chloride) and BMAC / BMAB (benzyltrimethylammonium chloride / bromide) pose a risk of generating byproducts due to PTC decomposition.

[0047] Therefore, in the present invention, by using sodium carbonate as a base catalyst, it is possible to produce nitromethane with excellent reactivity and high yield.

[0048] In one embodiment, the content of sodium carbonate may be 0.01 to 0.5 parts by weight, preferably 0.03 to 0.1 parts by weight, per 1 part by weight of dimethyl sulfate. Additionally, the molar concentration of sodium carbonate may be 0.01 to 0.5 mol.

[0049] In one embodiment, water is used as a solvent. Dimethyl sulfate, a major reaction component used in the present invention, is insoluble only in water, and sodium nitrite is soluble only in water. Therefore, water must be used as a solvent for the reaction to produce nitromethane, and as the reaction proceeds, dimethyl sulfate can be dissolved in water.

[0050] In one embodiment, the first step may maintain the reaction temperature at 5 to 20°C, preferably 10 to 15°C, using a cooling system. This reaction temperature range can provide a balance between the reaction rate and the impurity level. Generally, increasing the temperature increases the reaction rate, but promotes side reactions that are not required at high temperatures. Therefore, in the present invention, the reaction temperature is controlled to 5 to 20°C to prevent the hydrolysis of dimethyl sulfate by the solvent. This minimizes the generation of the byproduct methyl nitrite.

[0051] In one embodiment, the dropping of the first mixed solution may be performed under atmospheric pressure, but is not limited thereto.

[0052] In one embodiment, the dropping of the first mixed solution can be performed at a constant rate for 10 to 120 minutes.

[0053] In one embodiment, the first mixed solution may be added in several portions or added all at once.

[0054] In one embodiment, a second mixed solution is prepared through the first step.

[0055] In the present invention, the second step is to raise the temperature of the second mixed solution prepared in the first step to 60 to 80°C by its own reaction heat.

[0056] The second step can be performed by releasing the cooling system, and when the cooling system is released, dimethyl sulfate and sodium nitrite react to produce an aqueous nitromethane solution.

[0057] Reaction Scheme 1 below shows the reaction mechanism between dimethyl sulfate and sodium nitrite.

[0058] [Reaction Equation 1]

[0059]

[0060]

[0061] As shown in reaction scheme 1 above, nitromethane can be produced using dimethyl sulfate and sodium nitrite in the presence of a base catalyst with water as a solvent.

[0062] In one embodiment, the step comprises a first heating to 30 to 40°C for 10 to 30 minutes; and

[0063] It may include a second temperature increase to 60 to 80°C for 5 to 10 minutes.

[0064] When the above heating temperature exceeds 80°C, distillation of nitromethane and water produced by the azeotrope phenomenon begins, and there is a possibility that the reactants may be pumped out. Therefore, in the above step, a cooling system may be operated separately so that the heating temperature does not exceed 80°C.

[0065] In the present invention, the third step is to proceed with the reaction by stirring the heated second mixed solution for 30 minutes or less, and then cooling it to 20 to 45°C.

[0066] Through stirring in the third stage, any mixed or remaining reactions can be completed, and the aqueous nitromethane solution can be finally prepared.

[0067] In one embodiment, the total reaction time, i.e., steps 2 and 3, may be carried out for 180 minutes or less. When the reaction time is delayed at high temperatures, there is a risk that the yield may be reduced due to hydrolysis of the biological material by water. In the present invention, the yield of nitromethane can be maximized by optimizing reaction conditions such as reaction time.

[0068] In the present invention, the fourth step is to obtain nitromethane by vacuum distillation.

[0069] In one embodiment, vacuum distillation can be performed at 20 to 150 torr.

[0070] In one embodiment, salts, unreacted materials, and impurities can be removed through vacuum distillation. Through this, a distillate containing a mixture of water and nitromethane can be obtained.

[0071] In one embodiment, the distillate may undergo phase separation (upper layer: water, lower layer: nitromethane). Therefore, extraction may be further performed on the lower layer to remove water and obtain only pure nitromethane.

[0072] Through the manufacturing method according to the present invention, nitromethane with a high yield of 60% or more, 65% or more, 70% or more, 75% or more, or 80% or more can be produced.

[0073] In addition, nitromethane produced through the manufacturing method according to the present invention can have a high purity of 99% or more.

[0074] In addition, the nitromethane produced by the manufacturing method according to the present invention may contain 30% by weight or less of methyl nitrite, which is an impurity.

[0075] Nitromethane produced by conventional manufacturing methods has a low yield and contains a high proportion of methyl nitrite, an impurity. In particular, when methyl nitrite is contained in an amount greater than 30% to 40%, the methyl nitrite has a low boiling point, which causes it to vaporize into a gaseous form during the manufacturing process, raising concerns about gas generation during the reaction. That is, since the manufacturing method according to the present invention allows for the control of the content of methyl nitrite, an impurity, it is possible to stably produce nitromethane with high yield and purity.

[0076]

[0077] In addition, the present invention relates to nitromethane produced by the aforementioned manufacturing method.

[0078] The nitromethane according to the present invention can be provided as a transparent liquid.

[0079]

[0080] The present invention will be explained in detail below through the following experimental examples. However, the following experimental examples are merely illustrative of the present invention, and the scope of the present invention is not limited by the following experimental examples. Furthermore, since these experimental examples are intended only to aid in understanding the present invention, the scope of the present invention is not limited by them in any way.

[0081] Specific examples of the present invention will be described below with reference to the embodiments, but the scope of the present invention is not limited thereto.

[0082]

[0083] Examples

[0084] Example 1.

[0085] A 3-neck flask and an ice bath were prepared. DMS (1.00 mol) was added to the flask and stirred using a stirrer while cooling the temperature inside the reaction solution to 10–15°C. NaNO2 (0.85 mol) and Na2CO3 (0.02 mol) were completely dissolved in DIW and then fed into the flask at a uniform rate using a dropping funnel for 1 hour. During this time, the temperature of the reaction solution was maintained at 10–15°C.

[0086] After the input was complete, the mixture was stirred for 10 minutes, then the ice bath was removed to raise the temperature of the reaction solution using its own heat of reaction. Starting from an initial temperature of 15–30°C, the temperature rose to 30–40°C after about 20 minutes, and then rapidly increased to over 70°C within 5–10 minutes. Upon reaching 70–75°C, the temperature was controlled using an ice bath, and the mixture was stirred at 70°C for 30 minutes using a heating mantle. Once the reaction was complete, the solution was cooled to 40°C, and primary distillation was performed via vacuum distillation at 20–60 torr to obtain the (H2O + NM) solution.

[0087] The distilled liquid separated into a water layer and an NM layer, and NM crude was obtained from the NM solution through an extraction process. Subsequently, pure nitromethane was obtained by distilling the crude at atmospheric pressure.

[0088]

[0089] Example 2.

[0090] Nitromethane was prepared in the same manner as in Example 1, except that Na2CO3 (0.13 mol) was used for DMS (1.00 mol).

[0091]

[0092] Example 3.

[0093] Nitromethane was prepared in the same manner as in Example 1, except that Na2CO3 (0.02 mol) was used for DMS (1.00 mol).

[0094]

[0095] Example 4.

[0096] Nitromethane was prepared in the same manner as in Example 1, except that NaNO2 (1.00 mol) and Na2CO3 (0.02 mol) were used for DMS (1.00 mol).

[0097]

[0098] Example 5.

[0099] Nitromethane was prepared in the same manner as in Example 1, except that Na2CO3 (0.05 mol) was used for DMS (1.00 mol) and the initial reaction temperature was lowered to 5 degrees.

[0100]

[0101] Comparative Example 1.

[0102] NaNO2 (0.85 mol), Na2CO3 (0.13 mol), and DIW were added to a 3-neck or 4-neck flask and completely dissolved using a stirrer, while maintaining the internal temperature of the reaction mixture at room temperature. DMS (1.00 mol) was added to the flask at a uniform rate using a dropping funnel for 1 hour. After the addition was complete, the mixture was stirred for 10 minutes, and then the temperature of the reaction mixture was raised using the internal heat of reaction. The temperature rose rapidly starting from 30–40°C. Once it reached 70°C, the mixture was stirred at 70°C for 30 minutes using a heating mantle. Subsequently, primary purification was performed via vacuum distillation, and the resulting distillate was separated into phases to obtain the crude. The crude was then distilled at atmospheric pressure to obtain pure nitromethane.

[0103]

[0104] Comparative Example 2.

[0105] Nitromethane was prepared in the same manner as Comparative Example 1, except that NaNO2 (2.0 mol) was used for DMS (1.0 mol).

[0106]

[0107] Comparative Example 3.

[0108] Nitromethane was prepared in the same manner as Comparative Example 1, except that NaHCO3 (0.26 mol) was used for DMS (1.00 mol).

[0109]

[0110] Comparative Example 4.

[0111] A 3-neck or 4-neck flask and an ice bath were prepared. DMS (1 mol) was added to the flask, stirred using a stirrer, and the internal temperature of the reaction mixture was cooled to 10–15°C. KNO2 (2.0 mol) and Na2CO3 (0.26 mol) were completely dissolved in DIW and fed into the flask at a uniform rate using a dropping funnel for 1 hour. During this process, the temperature of the reaction mixture was maintained at 10–15°C. After the addition was complete, the mixture was stirred for 10 minutes, then the ice bath was removed to raise the temperature of the reaction mixture using its own heat of reaction. Once the temperature reached 55°C, a heating mantle was used to stir the mixture at 55°C for 30 minutes. Subsequently, primary purification was performed via vacuum distillation, and the resulting distillate was separated into phases to obtain the crude. The crude was then distilled at atmospheric pressure to obtain pure nitromethane.

[0112]

[0113] Comparative Example 5.

[0114] Nitromethane was prepared in the same manner as Comparative Example 1, except that NaNO2 (4.00 mol) was used for DMS (1.0 mol).

[0115]

[0116] Comparative Example 6.

[0117] Nitromethane was prepared in the same manner as in Example 1, except that Na2CO3 (0.26 mol) was used for DMS (1.00 mol) and the initial reaction temperature was lowered to 15 degrees.

[0118]

[0119] Comparative Example 7.

[0120] Nitromethane was prepared in the same manner as in Example 1, except that Na2CO3 was not used for DMS (1.00 mol).

[0121]

[0122] Comparative Example 8.

[0123] Nitromethane was prepared in the same manner as in Example 1, except that the initial reaction temperature was maintained at room temperature.

[0124]

[0125] Comparative Example 9.

[0126] Nitromethane was prepared in the same manner as in Example 1, except that Na2CO3 (0.5 mol) was used for DMS (1.00 mol).

[0127]

[0128] Comparative Example 10.

[0129] Nitromethane was prepared in the same manner as in Example 1, except that NaNO2 (2.00 mol) was used for DMS (1.0 mol) and ether was used as the mixed solvent.

[0130]

[0131] Comparative Example 11.

[0132] Nitromethane was prepared in the same manner as in Example 1, except that NaNO2 (2.00 mol) and TBAB (Tetrabutyl ammonium bromide) 0.05 mol were used for DMS (1.0 mol), and ether was used as the mixed solvent.

[0133]

[0134] Comparative Example 12.

[0135] Nitromethane was prepared in the same manner as in Example 1, except that NaNO2 (2.00 mol) and Triethylamine 0.05 mol were used for DMS (1.0 mol).

[0136]

[0137] Comparative Example 13.

[0138] Nitromethane was prepared in the same manner as in Example 1, except that NaNO2 (2.00 mol) and NaOH 0.05 mol were used for DMS (1.0 mol).

[0139]

[0140] Comparative Example 14.

[0141] Nitromethane was prepared in the same manner as Comparative Example 1, except that NaNO2 (2.00 mol) and Na2CO (30.05 mol) were used for DMS (1.0 mol) and the temperature was maintained at 30℃.

[0142]

[0143] Comparative Example 15.

[0144] Nitromethane was prepared in the same manner as Comparative Example 1, except that NaNO2 (2.00 mol), Na2CO3 0.05 mol, and Pyridine 0.2 mol were used for DMS (1.0 mol), and the temperature was maintained at 30℃.

[0145]

[0146] Comparative Example 16.

[0147] Nitromethane was prepared in the same manner as Comparative Example 1, except that NaNO2 (2.00 mol), Na2CO3 0.05 mol, and 18-crown-6 0.05 mol were used for DMS (1.0 mol), and the temperature was maintained at 30℃.

[0148]

[0149] Comparative Example 17.

[0150] Nitromethane was prepared in the same manner as Comparative Example 1, except that NaNO2 (2.00 mol) and Na2CO (30.05 mol) were used for DMS (1.0 mol), and the temperature was maintained at 30℃ and then raised to 100℃.

[0151]

[0152] Experimental Example 1. Yield Measurement

[0153] The yield and purity of the nitromethane produced in the examples and comparative examples were measured.

[0154] The results are listed in Table 1 below.

[0155]

[0156] DMS:NaNO2(eq.) Catalyst Dropping Method (Forward: DMS Dropping) Initial Temperature / Late Temperature Mixed Solvent Yield (%) Product Color Example 11 : 0.85Na2CO3, 0.05 Reverse 15℃ / 70℃ H2O 73 Purity 99.8% Transparent or colorless Example 21 : 0.85 Na2CO3, 0.13 Reverse 15℃ / 70℃ H2O 60 Transparent or colorless Example 31 : 0.85 Na2CO3, 0.02 Reverse 15℃ / 70℃ H2O 70 Transparent or colorless Example 41 : 1 Na2CO3, 0.02 Reverse 15℃ / 70℃ H2O 68 Transparent or colorless Example 51 : 0.85 Na2CO3, 0.05Reverse 5℃ / 70℃H2O75 Transparent or colorless Comparative Example 11 : 0.85Na2CO3, 0.13Forward 25℃ / 70℃H2O40 Transparent or colorless Comparative Example 21 : 2Na2CO3, 0.13Forward 25℃ / 70℃H2O26 Transparent or colorless Comparative Example 31 : 0.85NaHCO3, 0.26Forward 25℃ / 70℃H2O28 Transparent or colorless Comparative Example 41 : 2(KNO2)Na2CO3, 0.26Reverse 15℃ / 55℃H2O21 Transparent or colorless Comparative Example 51 : 4Na2CO3, 0.13 forward 25℃ / 70℃ H2O 20 transparent or colorless Comparative Example 61 : 0.85 Na2CO3, 0.26 reverse 15℃ / 70℃ H2O 49 transparent or colorless Comparative Example 71 : 0.85 no addition reverse 15℃ / 70℃ H2O 55 transparent or colorless Comparative Example 81 : 0.85 Na2CO3, 0.05 reverse 25℃ / 70℃ H2O 45 transparent or colorless Comparative Example 91 : 0.5 Na2CO3, 0.05 reverse 15℃ / 70℃ H2O 20 transparent or colorless Comparative Example 101 : 2 Na2CO3, 0.05 reverse 15℃ / 70℃ H2O / ether 20 transparent or colorless Comparative Example 111 : 2 TBAB, 0.05 Reverse 15℃ / 70℃ H2O / ether 3 3 Light yellow Comparative Example 121 : 2 Triethylamine, 0.05 Reverse 15℃ / 70℃ H2O 4 8 Light yellow Comparative Example 131 : 2 NaOH, 0.05 Reverse 15℃ / 70℃ H2O 2 2 Transparent or colorless Comparative Example 141 : 2 Na2CO 3 0.05 Forward 30℃ H2O 4 1 Transparent or colorless Comparative Example 151 : 2 Na2CO 3 0.05 Pyridine 0.2 Forward 30℃ H2O 4 6 Light yellow Comparative Example 161 : 2 Na2CO 3 0.05 18-crown-6 0.05 Forward 30℃ H2O 2 0 Light yellow Comparative Example 171 : 2 Na2CO 3 0.05 Forward 30℃ / 100℃ H2O 4 8 Transparent or colorless

[0157]

[0158] As described in Table 1 above, it can be confirmed that transparent nitromethane with a high yield of 60% or more can be produced when the ratio of DMS:NaNO2 is set to 1:1 or 1:0.85 as in the present invention, 0.02 to 0.13 mol of Na2CO3 is used as a catalyst, and the initial reaction temperature is maintained at 5-15°C.

[0159]

[0160] Experimental Example 2. Characterization of nitromethane

[0161] HPLC (High Performance Liquid Chromatography), gas chromatography, and NMR were performed on the nitromethane prepared in Example 2.

[0162] Specifically, HPLC analysis was performed using the Water e2695 Separations Module instrument, gas chromatography analysis was performed using the Agilent 8890 GC system instrument, and NMR analysis was performed using the Burker 600 MHz FT-NMR instrument.

[0163]

[0164] The analysis results are shown in Figures 1 to 3, respectively.

[0165] Figure 1 shows the HPLC analysis results of the nitromethane prepared in Example 1, and the progress of the reaction can be determined by whether the NaNO2 used as a reactant is consumed.

[0166] As shown in Figure 1, it can be confirmed that 1.89% of NaNO2 remains and 98.11% of nitromethane is produced through 1.231 min (NaNO2) and 2.300 min (nitromethane).

[0167] That is, nitromethane with a high yield can be produced through the method according to the example.

[0168]

[0169] Figure 2 shows the NMR analysis results of the nitromethane prepared in Example 1.

[0170] As shown in FIG. 2, it can be confirmed that the final product produced through the first and second distillation purification processes according to the present invention is nitromethane.

[0171]

[0172] In addition, Figure 3 shows the gas chromatography analysis results of the nitromethane produced in Example 2, confirming that nitromethane was produced.

[0173]

[0174] The method for producing nitromethane according to the present invention can produce nitromethane with high yield and purity while minimizing impurities by controlling the reaction temperature during the reaction process.

Claims

A step of preparing a second mixed solution by dropping a first mixed solution containing sodium nitrite (NaNO2), sodium carbonate (Na2CO3), and water onto dimethyl sulfate (DMS) under temperature conditions maintained at 1.5 to 20℃; A step of raising the temperature of the second mixed solution to 60 to 80°C by its own reaction heat; A step of carrying out the reaction by stirring for 30 minutes or less, and then cooling to 20 to 45°C; and A method comprising the step of obtaining nitromethane by vacuum distillation, Method for manufacturing nitromethane.

2. In Paragraph 1, A method for producing nitromethane in which the molar ratio of dimethyl sulfate to sodium nitrite is 1:0.7 to 1:1.

2.

3. In Paragraph 1, A method for producing nitromethane in which the sodium carbonate content is 0.01 to 0.5 parts by weight per 1 part by weight of dimethyl sulfate.

4. In Paragraph 1, A method for producing nitromethane, wherein the step of preparing the second mixed solution is to maintain the reaction temperature at 5 to 20°C using a cooling system.

5. In Paragraph 1, A method for producing nitromethane, wherein the step of preparing the second mixed solution is to dropwise add the first mixed solution at a constant rate for 10 to 120 minutes.

6. In Paragraph 1, The heating step is a first heating to 30 to 40°C for 10 to 30 minutes; and A method for producing nitromethane comprising a second heating to 60 to 80°C for 5 to 10 minutes.

7. In Paragraph 1, A method for producing nitromethane in which vacuum distillation is performed at 20 to 150 torr.

8. In Paragraph 1, A method for producing nitromethane in which the yield of nitromethane is 60% or more.

9. In Paragraph 1, A method for producing nitromethane in which the produced product contains 30 weight% or less of methyl nitrite.

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