Method for producing fluorine-containing dialkyl carbonate compounds

Abstract

The present invention relates to a method for producing fluorine-containing dialkyl carbonate compounds, which are suitable as non-aqueous solvents for non-aqueous electrolytes used in secondary batteries. When an alkyl chloroformate and an alcohol are reacted in the presence of an ether-containing imidazole derivative base, the reaction can be carried out at room temperature as compared with the prior art, and the products can be separated within a short time from the reactants. This is an economical process, and according to the present invention, it is possible to obtain alkyl carbonates containing fluorine atoms simply and without difficulty in the removal of solvents, salts formed during the reaction, and by-products.

Claims

1. A method for producing a dialkyl carbonate represented by the following Chemical Formula 3, comprising: reacting an alkyl chloroformate represented by the following Chemical Formula 1 and an alcohol represented by the following Chemical Formula 2 in the presence of a base, wherein the base is one or two or more selected from 1-(methoxymethyl)imidazole, 1-(ethoxymethyl)imidazole, 1-(propoxymethyl)imidazole, 1-(butoxymethyl)imidazole, 1-(2-methoxyethyl)imidazole, 1-(2-ethoxyethyl)imidazole, 1-(2-propoxyethyl)imidazole, 1-(2-butoxyethyl)imidazole, 1-(3-methoxypropyl)imidazole, and 1-(3-ethoxypropyl)imidazole: ##STR00003## wherein, R.sub.1 and R.sub.2 are each independently an unsubstituted C.sub.1-C.sub.20 alkyl group and a fluorine-substituted C.sub.1-C.sub.20 alkyl group.

2. The method for producing a dialkyl carbonate of claim 1, wherein the reaction temperature is in the range of 10 to 35 C.

3. The method for producing a dialkyl carbonate of claim 1, wherein the reaction product is separated from the reactants by layer separation.

4. The method for producing a dialkyl carbonate of claim 1, wherein the base is 1-(2-ethoxyethyl)imidazole.

5. The method for producing a dialkyl carbonate of claim 1, wherein the reaction time is less than 6 hours.

6. The method for producing a dialkyl carbonate of claim 1, wherein the mixing molar ratio of the base, the alkyl chloroformate and the alcohol is 1:1:1.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

(1) Hereinafter, the present invention will be described in more detail by way of Examples. It should be understood that the terms or words used in the specification and the appended claims should not be construed as limited to general and dictionary meanings, but interpreted based on the meanings and concepts corresponding to technical aspects of the present disclosure. Therefore, the embodiments disclosed in the present specification are merely the most preferred embodiments of the present disclosure, and not all of them represent the technical ideas of the present disclosure, and thus it should be understood that there may be various equivalents and modified examples that could substitute therefore at the time of filing the present application.

Example 1: Preparation of Methyl 2,2,2-trifluoroethyl Carbonate

(2) 100 g of methyl chloroformate and 106 g of 2,2,2-trifluoroethanol were added to a 1000-mL reactor equipped with a stirrer, and the mixture was stirred at room temperature for 30 minutes. 149 g of 1-(2-ethoxyethyl)imidazole was placed in a dropping funnel equipped in the reactor head, then added dropwise for 2 hours and stirred at room temperature for 3 hours. After completion of the reaction, the layers were separated to obtain methyl 2,2,2-trifluoroethyl carbonate as a transparent liquid in a yield of 88%.

Examples 2 to 4: Preparation of Methyl Fluoroalkyl Carbonate Compounds

(3) The reaction was carried out in the same manner as in Example 1, except that the type of alcohols was varied. The results are shown in Table 1 below.

(4) TABLE-US-00001 TABLE 1 Examples Alcohol compounds Yield (%) 2 Hexafluoro-iso-propanol 85 3 2,2,3,3-tetrafluoropropanol 80 4 2,2,3,3,3-pentafluoropropanol 90

Example 5: Preparation of Ethyl 2,2,2-trifluoroethyl Carbonate

(5) 100 g of ethyl chloroformate and 92 g of 2,2,2-trifluoroethanol were added to a 1000-mL reactor equipped with a stirrer, and the mixture was stirred at room temperature for 30 minutes. 129 g of 1-(2-ethoxyethyl)imidazole was placed in a dropping funnel equipped in the reactor head, then added dropwise for 2 hours and stirred at room temperature for 3 hours. After completion of the reaction, the layers were separated to obtain ethyl 2,2,2-trifluoroethyl carbonate as a transparent liquid in a yield of 92%.

Examples 6 to 8: Preparation of Ethyl Fluoroalkyl Carbonate

(6) The reaction was carried out in the same manner as in Example 5, except that the type of alcohol compounds was varied. The results are shown in Table 2 below.

(7) TABLE-US-00002 TABLE 2 Examples Alcohol compounds Yield (%) 6 Hexafluoro-iso-propanol 85 7 2,2,3,3-tetrafluoropropanol 85 8 2,2,3,3,3-pentafluoropropanol 90

Examples 9 to 14: Preparation of Fluorodialkyl Carbonate

(8) The reaction was carried out in the same manner as in Example 1, except that the molar ratio was varied. The results are shown in Table 3 below.

(9) TABLE-US-00003 TABLE 3 Methyl 2,2,2- 1-(2-ethoxyethyl) Yield Examples chloroformate trifluoroethanol imidazo1e (%) 9 0.9 1 1 65 10 1 0.9 1 72 11 1 1 0.9 70 12 1.1 1 1 88 13 1 1.1 1 88 14 1 1 1.1 60

Examples 15 to 19: Preparation of Fluorodialkyl Carbonate

(10) The reaction was carried out in the same manner as in Example 1, except that the reaction temperature was varied. The results are shown in Table 4 below.

(11) TABLE-US-00004 TABLE 4 Examples Reaction Temperature ( C.) Yield (%) 15 0 45 16 10 88 17 35 88 18 50 85 19 70 70

Examples 20 to 24: Preparation of Fluorodialkyl Carbonate

(12) The reaction was carried out in the same manner as in Example 1, except that the reaction time was varied. The results are shown in Table 5 below.

(13) TABLE-US-00005 TABLE 5 Examples Reaction Time (h) Yield (%) 20 0.5 50 21 1 60 22 2 80 23 4 88 24 6 88