Preparation method of 1-fluoromethyl methyl carbonate

Abstract

The invention discloses a preparation method of 1-fluoromethyl methyl carbonate, which is characterized by comprising the following steps: 1, 1-chloromethyl methyl carbonate is dissolved in a mixed solvent, the mixed solvent comprises an organic phase and a water phase, and the water phase is deionized water; adding a catalytic amount of iodized salt and an excessive amount of acidic fluorination reagent, and carrying out nucleophilic fluorination reaction at 25-80 DEG C; the iodized salt is selected from one of sodium iodide, potassium iodide and tetrabutylammonium iodide, and the feeding molar ratio of the iodized salt to the 1-chloromethyl methyl carbonate is 0.05-0.2; and 2, after the reaction is completed, washing the reaction liquid with water, concentrating to remove the organic solvent, and carrying out reduced pressure rectification on the concentrated liquid to obtain the 1-fluoromethyl methyl carbonate product. The method has the advantages that reaction conditions are mild and controllable, the process is simple, aftertreatment is convenient, the product purity is 99.6% or above, the yield is generally 91% or above, the highest yield can reach 96.76%, the product purity and yield are both greatly improved, and industrial production is greatly facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of compound synthesis, and in particular to a method for preparing 1-fluoromethyl methyl carbonate. Background Art

[0002] Fluorine-containing materials have excellent properties and have been widely used in aerospace, military industry, integrated circuits, electronic gases, photovoltaic energy, lithium-ion batteries and other fields in recent years, especially in the field of lithium batteries.

[0003] The strong electronegativity of fluorine is conducive to increasing the reduction potential of solvent molecules on the surface of carbon negative electrode, optimizing the solid electrolyte interface film, improving the compatibility between lithium battery electrolyte and positive and negative electrode materials, and thus stabilizing the electrochemical performance of the electrode. In addition, fluorinated carbonates all have high flash points. Adding them to lithium battery electrolytes can improve thermal stability, and the SEI film structure layer formed is tighter without increasing impedance, which can prevent further decomposition of the electrolyte and improve the low-temperature performance of the electrolyte.

[0004] At present, the known synthesis method of 1-fluoromethyl methyl carbonate is to use 18-crown ether-6 as a heterogeneous catalyst to react 1-chloromethyl methyl carbonate with potassium fluoride to generate 1-fluoromethyl methyl carbonate by nucleophilic fluorination, such as the technical solution disclosed in WO2011006822. The technical problems existing in this process are: long reaction time, a large amount of raw materials cannot be consumed completely, many by-products, extremely low yield, low product purity, and unfavorable for industrial production. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method for preparing 1-fluoromethyl methyl carbonate, wherein the raw materials of the method are easy to obtain, the preparation time is short, the post-treatment is simple, and the yield and purity are high.

[0006] To solve the above problems, the technical solution adopted by the present invention includes: a method for preparing 1-fluoromethyl methyl carbonate, comprising the following steps: 1. dissolving 1-chloromethyl methyl carbonate in a mixed solvent, the mixed solvent comprising an organic phase and an aqueous phase, the aqueous phase being deionized water; after adding a catalytic amount of iodine salt and an excess of an acidic fluoriding agent, a nucleophilic fluorination reaction occurs at 25°C to 80°C; the iodine salt is selected from one of sodium iodide, potassium iodide, and tetrabutylammonium iodide, and the molar ratio of the iodine salt to the 1-chloromethyl methyl carbonate is 0.05 to 0.2; 2. after the reaction is completed, washing the reaction solution with water, concentrating to remove the organic solvent, and subjecting the concentrated solution to vacuum distillation to obtain the 1-fluoromethyl methyl carbonate product.

[0007] The reaction principle is as follows: .

[0008] Furthermore, in the aforementioned method for preparing 1-fluoromethyl methyl carbonate, the organic phase in the mixed solvent is selected from any one of diethyl ether, methyl tert-butyl ether, tetrahydrofuran, dioxane, acetone, and acetonitrile.

[0009] Furthermore, in the aforementioned method for preparing 1-fluoromethyl methyl carbonate, the organic phase in the mixed solvent is methyl tert-butyl ether.

[0010] Furthermore, in the aforementioned method for preparing 1-fluoromethyl methyl carbonate, the iodine salt is tetrabutylammonium iodide.

[0011] Furthermore, in the aforementioned method for preparing 1-fluoromethyl methyl carbonate, the acidic fluorination agent is selected from one of triethylamine trihydrofluoride, pyridine hydrofluoride, ammonium bifluoride, and potassium bifluoride; and the molar ratio of the acidic fluorination agent to 1-chloromethyl methyl carbonate is 1.5 to 3.

[0012] Furthermore, in the aforementioned method for preparing 1-fluoromethyl methyl carbonate, the acidic fluorination reagent is pyridine hydrofluoride.

[0013] Furthermore, in the aforementioned method for preparing 1-fluoromethyl methyl carbonate, after the reaction is completed, the reaction solution is washed with water at least once.

[0014] Furthermore, in the aforementioned method for preparing 1-fluoromethyl methyl carbonate, the nucleophilic fluorination reaction time is 2 to 8 hours.

[0015] Furthermore, in the aforementioned method for preparing 1-fluoromethyl methyl carbonate, the mass ratio of the organic phase to deionized water is 10-5.

[0016] The advantages of the present invention are: mild and controllable reaction conditions, simple process, convenient post-treatment, product purity of 99.6% or above, yield generally above 91%, and up to 96.76%, product purity and yield are greatly improved, and it is extremely beneficial to industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is the H NMR spectrum of the finished product of 1-fluoromethyl methyl carbonate in Example 2, 1 H NMR (400MHz, CDCl3) δ5.75 (1H,s), 5.66 (1H,s), 3.88 (3H,s).

[0018] Figure 2 This is the NMR carbon spectrum of the finished product of 1-fluoromethyl methyl carbonate in Example 2 13C NMR (100MHz, CDCl3) δ154.43, 97.20, 95.72, 55.68. Implementation

[0019] The preparation method of 1-fluoromethyl methyl carbonate of the present invention is described in detail below through specific examples.

[0020] Example 1: In a three-necked jacketed kettle equipped with a thermometer and a stirrer, 125 g of 1-chloromethyl methyl carbonate, 250 g of acetonitrile, 50 g of deionized water, 30 g of sodium iodide, and 245 g of triethylamine trihydrofluoride were added, stirred evenly, heated to 80°C and refluxed for 5 hours, then the reaction was stopped and cooled to room temperature.

[0021] The reaction solution was washed with water three times and then concentrated to remove acetonitrile. The concentrate was subjected to vacuum distillation to obtain 97 g of 1-fluoromethyl methyl carbonate. The purity was 99.73% as determined by GC (gas chromatography). The calculated molar yield was 89.81%.

[0022] Example 2: In a three-necked jacketed kettle equipped with a thermometer and a stirrer, 250 g of 1-chloromethyl methyl carbonate, 500 g of methyl tert-butyl ether, 62.5 g of deionized water, 74 g of tetrabutylammonium iodide, and 397 g of pyridine hydrofluoride were added, stirred evenly, heated to 56°C and refluxed for 3 h, then the reaction was stopped and cooled to room temperature.

[0023] The reaction solution was washed with water three times, concentrated to remove methyl tert-butyl ether, and the concentrate was distilled under reduced pressure to obtain 209 g of 1-fluoromethyl methyl carbonate. The purity was 99.92% as determined by GC (gas chromatography), and the calculated molar yield was 96.76%. The product NMR hydrogen spectrum is shown in Figure 1 , NMR carbon spectrum see Figure 2 .

[0024] Example 3: In a three-necked jacketed kettle equipped with a thermometer and a stirrer, 200 g of 1-chloromethyl methyl carbonate, 400 g of tetrahydrofuran, 50 g of deionized water, 53 g of potassium iodide and 238 g of pyridine hydrofluoride were added, stirred evenly, heated to 66° C. and refluxed for 4 h, then the reaction was stopped and cooled to room temperature.

[0025] The reaction solution was washed with water three times, concentrated to remove tetrahydrofuran, and the concentrate was distilled under reduced pressure to obtain 162 g of 1-fluoromethyl methyl carbonate. The purity was 99.81% as detected by GC (gas chromatography), and the calculated molar yield was 93.75%.

[0026] Example 4: In a three-necked jacketed kettle equipped with a thermometer and a stirrer, 225 g of 1-chloromethyl methyl carbonate, 450 g of dioxane, 45 g of deionized water, 33.4 g of tetrabutylammonium iodide and 160 g of ammonium hydrogen fluoride were added, stirred evenly, heated to 80°C and refluxed for 6 h, then the reaction was stopped and cooled to room temperature.

[0027] The reaction solution was washed with water three times and then concentrated to remove dioxane. The concentrate was subjected to vacuum distillation to obtain 177 g of 1-fluoromethyl methyl carbonate. The purity was 99.79% as determined by GC (gas chromatography). The calculated molar yield was 91.05%.

[0028] Example 5: In a three-necked jacketed kettle equipped with a thermometer and a stirrer, 175 g of 1-chloromethyl methyl carbonate, 350 g of ether, 50 g of deionized water, 42 g of sodium iodide, and 273 g of potassium bifluoride were added, stirred evenly, heated to 35°C and refluxed for 8 hours, then the reaction was stopped and cooled to room temperature.

[0029] The reaction solution was washed with water three times and then concentrated to remove ether. The concentrate was subjected to vacuum distillation to obtain 139 g of 1-fluoromethyl methyl carbonate. The purity was 99.65% as determined by GC (gas chromatography). The calculated molar yield was 91.93%.

[0030] Example 6: In a three-necked jacketed kettle equipped with a thermometer and a stirrer, 150 g of 1-chloromethyl methyl carbonate, 300 g of acetone, 30 g of deionized water, 39 g of potassium iodide, and 358 g of pyridine hydrofluoride were added, stirred evenly, heated to 56°C and refluxed for 3 h, then the reaction was stopped and cooled to room temperature.

[0031] The reaction solution was washed with water three times and then concentrated to remove acetone. The concentrate was subjected to vacuum distillation to obtain 121 g of 1-fluoromethyl methyl carbonate. The purity was 99.87% as determined by GC (gas chromatography). The calculated molar yield was 93.36%.

[0032] Example 7: In a three-necked jacketed kettle equipped with a thermometer and a stirrer, 225 g of 1-chloromethyl methyl carbonate, 450 g of methyl tert-butyl ether, 75 g of deionized water, 67 g of tetrabutylammonium iodide, and 438 g of triethylamine trihydrofluoride were added, stirred evenly, heated to 56°C and refluxed for 5 hours, then the reaction was stopped and cooled to room temperature.

[0033] The reaction solution was washed with water three times and then concentrated to remove methyl tert-butyl ether. The concentrate was distilled under reduced pressure to obtain 182 g of 1-fluoromethyl methyl carbonate. The purity was 99.76% as determined by GC (gas chromatography). The calculated molar yield was 93.62%.

[0034] In the above embodiments, first, a mixed solvent formed by an organic phase and an aqueous phase is used to increase the solubility of the catalyst and the fluorinating agent, which promotes the reaction to proceed in a positive direction and greatly improves the reaction efficiency. Second, an iodine salt is added as a catalyst to enhance the leaving ability of the chlorine atom in 1-chloromethyl methyl carbonate, thereby further promoting the positive reaction. Third, an acidic fluorinating agent is used to effectively avoid the decomposition of 1-chloromethyl methyl carbonate to generate alcohol and carbon dioxide during the heating reaction. The above three points promote the efficient conduction of the nucleophilic fluorination reaction.

[0035] Comparative Example 8: In a three-necked jacketed kettle equipped with a thermometer and a stirrer, 125 g of 1-chloromethyl methyl carbonate, 300 g of ether, 116 g of potassium iodide, and 26 g of 18-crown ether-6 were added, stirred evenly, and reacted vigorously at 25° C. for 24 h, then the reaction was stopped.

[0036] The reaction solution was filtered, and the filtrate was concentrated to remove ether, and then vacuum distilled to obtain 5 g of 1-fluoromethyl methyl carbonate. The purity was 96.38% as detected by GC (gas chromatography), and the calculated molar yield was 4.63%.

[0037] The experimental results of Comparative Example 8 show that the method of synthesizing 1-fluoromethyl methyl carbonate using potassium fluoride has the disadvantages of long reaction time, low yield, many by-products, and low product purity.

[0038] It can be seen from the above embodiments that the preparation method of 1-fluoromethyl methyl carbonate of the present invention has mild and controllable reaction conditions, simple process, convenient post-treatment, product purity of 99.6% and above, and yield generally above 91%, up to 96.76%, which greatly improves product purity and yield, and is extremely conducive to industrial production.

Claims

1. A method for preparing 1-fluoromethyl methyl carbonate, characterized in that: The following steps are involved:

1. Dissolve 1-chloromethyl methyl carbonate in a mixed solvent, the mixed solvent comprises an organic phase and an aqueous phase, and the aqueous phase is deionized water; after adding a catalytic amount of iodine salt and an excess of an acidic fluorination agent, a nucleophilic fluorination reaction occurs at 25°C to 80°C; the iodine salt is selected from one of sodium iodide, potassium iodide, and tetrabutylammonium iodide, and the molar ratio of the iodine salt to 1-chloromethyl methyl carbonate is 0.05 to 0.2; 2. After the reaction is completed, wash the reaction solution with water, concentrate to remove the organic solvent, and conduct vacuum distillation of the concentrated solution to obtain the 1-fluoromethyl methyl carbonate product.

2. The method for preparing 1-fluoromethyl methyl carbonate according to claim 1, characterized in that: The organic phase in the mixed solvent is selected from any one of diethyl ether, methyl tert-butyl ether, tetrahydrofuran, dioxane, acetone and acetonitrile.

3. A method for preparing 1-fluoromethyl methyl carbonate according to claim 2, characterized in that: The organic phase in the mixed solvent is methyl tert-butyl ether.

4. The method for preparing 1-fluoromethyl methyl carbonate according to claim 1, characterized in that: The iodized salt is tetrabutylammonium iodide.

5. The method for preparing 1-fluoromethyl methyl carbonate according to claim 1, characterized in that: The acidic fluorination agent is selected from one of triethylamine trihydrofluoride, pyridine hydrofluoride, ammonium bifluoride and potassium bifluoride; the molar ratio of the acidic fluorination agent to 1-chloromethyl methyl carbonate is 1.5-3.

6. The method for preparing 1-fluoromethyl methyl carbonate according to claim 5, characterized in that: The acidic fluorination reagent is pyridine hydrofluoride.

7. The method for preparing 1-fluoromethyl methyl carbonate according to claim 1, characterized in that: After the reaction is completed, the reaction solution is washed with water at least once.

8. The method for preparing 1-fluoromethyl methyl carbonate according to claim 1, characterized in that: The nucleophilic fluorination reaction time is 2 to 8 hours.

9. The method for preparing 1-fluoromethyl methyl carbonate according to claim 1, characterized in that: The mass ratio of the organic phase to the deionized water is 10-5.

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