KR20080114198A - A method for preparation of mono-halogenated ethylene carbonate - Google Patents

Abstract

A preparation method of mono-halogenated ethylene carbonate is provided to facilitate the keeping and handling of the materials used and to be suitable for the mass production due to less by-products and simple refining process. A preparation method of chloroethylene carbonate comprises (a) a step for manufacturing the mixed solution by mixing ethylene carbonate and carbon tetrachloride; (b) a chlorination step for injecting Cl2 gas to the mixed solution and light-irradiating it with a halogen lamp; (c) a step for removing carbon tetrachloride; and (d) a step for obtaining the chloroethylene carbonate by using the distillation under reduced pressure. The chlorination reaction step maintains the mixed solution in a range of 55-60‹C.

Description

A method for preparation of mono-halogenated ethylene carbonate

1 shows an apparatus for producing chloroethylene carbonate according to the present invention,

Figure 2 shows a reduced pressure fractional distillation apparatus according to the present invention,

3 shows an apparatus for producing fluoroethylene carbonate from chloroethylene.

<Explanation of symbols for the main parts of the drawings>

110, 210, 310: reactor 111, 211, 311: agitator

112, 212, 312: temperature controller 120: photoreaction unit

121, 122, 123: photoreactor 124: halogen lamp

151, 152: solvent recovery tank 160, 260, 360: reflux cooler

220: distillation column 251, 252, 351: storage tank

320: filter

The present invention relates to a method for producing halogenated ethylene carbonate, and more particularly, to a method for producing chloroethylene carbonate (CEC) and fluoroethylene carbonate (FEC).

Halogenated ethylene carbonate is added to the solvent in an electrochemical cell and the compound is used to increase the stability of the electrode material. In addition, the halogenated ethylene carbonate is used as an intermediate for producing vinylene carbonate used in the electrolyte solution for electrochemical cells.

Chloroethylene carbonate is usually synthesized by chlorination of ethylene carbonate. U.S. Patent No. 3,021,340 discloses a method for producing chloroethylene carbonate by heating ethylene carbonate to boiling point in carbon tetrachloride and anhydrous iron chloride and then passing chlorine gas, but a mixture of chloroethylene carbonate and dichloroethylene carbonate is produced and the yield is low. There is this.

Korean Patent Laid-Open Publication No. 2001-0090814 discloses a method of selectively preparing monochloroethylene carbonate by UV irradiation using SO ₂ Cl ₂ in the absence of a solvent. The patent has a disadvantage in that it is difficult to apply to mass production due to the excessive use of by-products such as SO ₂ by the excessive use of the liquid SO ₂ Cl ₂ as well as the high corrosiveness and handling difficulties of SO ₂ Cl ₂ .

On the other hand, fluoroethylene carbonate is a substance which is usefully used as a solvent, additive, organic solvent, or intermediate of pharmaceuticals for electrolytes of lithium secondary batteries, and is usually obtained by directly fluorinating ethylene carbonate using fluorine gas. However, the conventional method has a low reaction selectivity, so that difluoro products are always produced together, causing a problem of separation, and a low yield of mono substituted products. In addition, fluorine gas having a very high toxicity and high corrosiveness is used, which is a major problem in the ease of manufacture and stability in the manufacturing process.

It is an object of the present invention to provide a method for selectively preparing chloroethylene carbonate from ethylene carbonate. That is, the present invention has been made to solve the disadvantages of the prior art that the yield is low and a mixture of chloroethylene carbonate and dichloroethylene carbonate is produced, the object is to provide a method for producing chloroethylene carbonate with high yield and high purity have. In another aspect, the present invention is to provide an economical, safe and eco-friendly manufacturing method suitable for mass production in the production method of chloroethylene carbonate is less by-products than the conventional method, the purity and yield is high, the purification process is simple There is a purpose.

In addition, the present invention has another object to provide a manufacturing method for producing a high purity fluoroethylene carbonate from the monochloroethylene carbonate prepared by the above production method.

The present invention relates to a method for producing chloroethylene carbonate and fluoroethylene carbonate from ethylene carbonate, specifically a method for selectively producing chloroethylene carbonate by injecting chlorine gas into ethylene carbonate and light irradiation with a halogen lamp The present invention relates to a method for producing fluoroethylene carbonate by a fluorine substitution reaction by adding a fluorine salt to the prepared chloroethylene carbonate.

The manufacturing method according to the present invention has the advantage of being suitable for mass production because the material to be used is inexpensive, safe, easy to store and handle, and there is little by-product generation, thus simplifying the purification process. In addition, by using a chlorine gas as a material used for the chlorination reaction and a halogen lamp as a light source suitable for the decomposition and selective substitution thereof, there is an advantage that the chlorethylene one substituted chloroethylene carbonate can be selectively produced in a high yield. Conventionally, the method using UV has a problem that the separation process is complicated due to the large amount of dichloroethylene carbonate being produced, and the yield of chloroethylene carbonate is lowered. However, when halogen lamp is used instead of UV, the chlorine gas is activated and replaced. By supplying the appropriate energy it was possible to selectively prepare chloroethylene carbonate substituted with one chlorine.

In addition, the short wavelength UV transmits through the reactants using a solvent so that it is difficult for UV to penetrate deep inside the reactants. Therefore, the reaction of the reactants due to the irradiated light does not occur efficiently. Since the wavelength is long, there is an advantage that the light energy can be transferred deep into the reactant.

Hereinafter, the present invention will be described in more detail.

At this time, if there is no other definition in the technical terms and scientific terms used, it has a meaning commonly understood by those of ordinary skill in the art.

In addition, repeated description of the same technical configuration and operation as in the prior art will be omitted.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided as examples to sufficiently convey the spirit of the present invention to those skilled in the art. Accordingly, the invention is not limited to the embodiments described below and may be embodied in other forms. In the drawings, lengths, thicknesses, and the like of layers and regions may be exaggerated for convenience. Like numbers refer to like elements throughout.

The method for producing chloroethylene carbonate according to the present invention comprises the following steps.

a) mixing the ethylene carbonate and carbon tetrachloride to prepare a mixed solution;

b) a chlorination reaction for injecting chlorine gas into the mixed solution and irradiating with a halogen lamp;

c) removing carbon tetrachloride; And

d) obtaining chloroethylene carbonate by distillation under reduced pressure.

The method for producing chloroethylene carbonate according to the present invention can be represented by the following Scheme 1.

Scheme 1

The manufacturing method according to the present invention can be made through a manufacturing apparatus as shown in FIG. Referring to FIG. 1, a manufacturing apparatus includes a reactor 110 in which ethylene carbonate and carbon tetrachloride are added and mixed, and a plurality of photoreactors equipped with halogen lamps are ethylene carbonate and a solvent as raw materials in the photoreaction unit 120 connected in parallel. Carbon tetrachloride is injected, circulating pumps 131, 132, and 133 for circulating the mixed solution of ethylene carbonate and carbon tetrachloride through a photoreactor at a constant flow rate from the reactor 110, and the circulation pump and the photoreaction unit 120. Located between the chlorine gas injection unit 140, which injects chlorine gas into the mixed solution, and the photoreaction unit 20 is a plurality of photoreactors 121, 122, 123 are connected in parallel The photoreactor is provided with a plurality of halogen lamps 124 to produce chloroethylene carbonate by light irradiation using a halogen lamp 124 to the mixed solution in which chlorine gas is injected The. The mixed solution passed through the photoreaction unit 120 includes carbon tetrachloride as a solvent and hydrogen chloride (HCl) as a by-product in addition to unreacted ethylene carbonate and chloroethylene carbonate. The mixed liquid passing through the photoreaction unit 120 is circulated back to the reactor and repeats the above circulation process. The reactor 110 includes an ethylene carbonate injector, a solvent injector, a stirrer 111, and a temperature control device 112. The temperature control device is formed on the outer wall of the reactor using steam and tap water. The temperature of the reactor can be adjusted in the range of 55 to 65 ° C. while circulating the part.

The manufacturing method using the manufacturing apparatus shown in FIG. 1 will be described in detail as follows. Ethylene carbonate and carbon tetrachloride are added to the reactor 110. 100 to 500 parts by weight of carbon tetrachloride are used with respect to 100 parts by weight of ethylene carbonate and mixed with a stirrer in the reactor. In the present reaction, it is preferable to maintain the reactor at 55 to 60 ° C., because the reaction does not proceed properly when the temperature is lower than the temperature, and when the temperature is higher than the temperature, the reaction rate may increase to generate dichloroethylene carbonate. to be.

When the mixed solution in the reactor is maintained in the temperature range it is circulated to the photoreaction unit 120 through the circulation pump. Chlorine gas is injected before passing through a photoreactor equipped with a halogen lamp in the photoreaction section. Before the chlorine gas injection, the photoreactor becomes yellow by ethylene carbonate and disappears yellow and becomes transparent color by reaction with chlorine gas. If an excess of chlorine gas is injected, a lot of dichloroethylene carbonate is produced, and the upper end of the loop reactor becomes green due to chlorine gas. Therefore, it is preferable to inject chlorine gas so that the top of the photoreactor becomes a transparent color. Chlorine carbonate is formed by the chlorination reaction as the mixed solution in which chlorine gas is injected passes through a ê * reactor where light is irradiated with a halogen lamp, and HCl is produced as a reaction by-product. The photoreactor is preferably filled with a glass bead (glass bead) to increase the light irradiation surface area, it is preferable to connect a large number of photoreactors in parallel to process a large amount of reactants in a short time. Halogen lamps emit light in the wavelength range from visible to near infrared, and there is no need to limit the type of halogen lamp.

The reaction time is terminated when the content of ethylene carbonate is less than 5% by weight by gas chromatography (GC) analysis. Usually after 48 hours it is recommended to measure the residual ethylene carbonate content by GC. At the end of the reaction, atmospheric distillation is performed to recover carbon tetrachloride from the solvent recovery tanks 151 and 152 through a reflux condensor 160. The recovery rate of the carbon tetrachloride distilled at atmospheric pressure is 80%, and the remaining carbon tetrachloride and HCl remove the reactor under reduced pressure distillation, for example, 50 ° C. and 5 torr.

As described above, the product from which the solvent and the HCl have been removed is transferred from the reactor to the vacuum distillation apparatus. The reduced pressure fractional distillation apparatus according to the present invention is shown in FIG. 2. Referring to FIG. 2, unpurified chloroethylene carbonate is introduced into the reactor 210, and the reactor 210 maintains the reactor at a constant temperature with a temperature control device 212, and a distillation column 220 is connected to the top of the reactor. The steam passing through the distillation column 220 is cooled in the reflux cooler 260 and stored in the storage tanks 251 and 252. The distillation under reduced pressure of the chloroethylene carbonate is a material that is heated to a temperature of 70 to 80 ℃ ℃ and distilled below 70 ℃ while maintaining the reactor pressure of about 2 to 4 torr through a vacuum line connected to the reactor Only substances which are regarded as impurities and distilled in the above temperature range are obtained.

The following describes a method for producing fluoroethylene carbonate using the chloroethylene carbonate produced by the above production method.

Fluoroethylene carbonate production method according to the invention is characterized in that it comprises the following steps.

a) preparing a fluorine solution by adding a fluorine salt and a solvent to the reactor;

b) injecting chloroethylene carbonate prepared by the production method according to the present invention to the fluoride salt solution;

c) heating the reactor to 90 to 95 ° C. for fluorine substitution reaction; And

d) cooling the reactor to room temperature and then filtration under reduced pressure to remove the chloride salt and recover the solvent.

The manufacturing method may further comprise the step of obtaining a fluoroethylene carbonate by distillation under reduced pressure after the solvent recovery step.

The method for producing fluoroethylene carbonate according to the present invention can be represented by the following Scheme 2. However, other fluorine salts may be used in addition to KF, and other solvents may be used in addition to dimethyl carbonate (DMC). As the fluoride salts, alkali fluoride salts such as lithium fluoride, sodium fluoride, potassium fluoride, calcium fluoride and magnesium fluoride are preferable, and potassium fluoride is most preferable in terms of yield. Also in the case of solvent, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, ethylene glycol, acetonitrile , Formamide, acetamide, dimethylsulfoxide or mixtures thereof may be used, but dimethyl carbonate is most preferred in terms of fluoroethylene carbonate yield and solvent recovery.

Scheme 2

Steps a) and b) are preferably maintained at a temperature of 0 to 15 ℃, which may cause a problem that the reaction may occur suddenly when the chloroethylene carbonate is added when the temperature exceeds 15 ℃ It is not desirable to maintain the temperature below 0 ° C., since the cost for the manufacturing apparatus increases as well as the effect thereof is negligible.

In addition, the temperature at which the fluorine substitution reaction takes place is 90 to 95 ℃ is appropriate. This is not appropriate because the reaction does not proceed properly when the temperature is less than 90 ℃ and the temperature is not only increased the cost of the manufacturing apparatus to increase the temperature above 95 ℃ and the effect is small.

In addition, the step a) to c) is preferably carried out in an inert gas atmosphere, such as nitrogen, when the reaction in the nitrogen atmosphere is reduced to other side reactions to help improve the reaction yield.

An example of the said fluoroethylene carbonate manufacturing apparatus is shown in FIG. Referring to FIG. 3, a reactor 310 for producing fluoroethylene carbonate, a filter 320 for vacuum filtering the by-product potassium chloride salt from the reactor, a storage tank 351 for storing the product filtered from the filter, and a reflux cooler The reactor 310 includes a solvent and a chloroethylene carbonate injection unit, a nitrogen injection unit, an exhaust line, and a vacuum line, and includes a temperature control device 312 and a stirrer 311. The temperature control device can control the temperature while circulating the space formed on the outer wall of the reactor using steam and tap water similarly to that shown in FIG.

Nitrogen is flowed into the reactor to make the reactor into a nitrogen atmosphere, and then solvent and fluorine are introduced into the reactor. The amount of fluorine salt used is preferably 1 to 2 equivalents relative to chloroethylene carbonate. The solvent is suitably added in an amount of 1 to 3 parts by volume relative to chloroethylene carbonate.

The temperature of the reactor is maintained at 15 ° C. or lower and stirred while adding chloroethylene carbonate prepared by the production method according to the present invention. After stirring for 0.5 to 2 hours to allow the reactants to be completely mixed, the reactor is heated to 90 to 95 ° C. to allow fluorine substitution. The reaction termination is analyzed by GC and the reaction is terminated when the chloroethylene carbonate is less than 0.5% by weight, usually about 48 hours. After the reaction is completed, the reactor is cooled to room temperature, and the by-product chloride is removed by filtration under reduced pressure. After filtration is completed, the solvent is recovered by distillation under reduced pressure, and when the solvent recovery is completed, fluoroethylene carbonate is obtained by short distillation under reduced pressure, and the distillation is carried out under reduced pressure to obtain a fluoroethylene carbonate by distillation under reduced pressure. The fluoroethylene carbonate vacuum distillation apparatus may be made by an apparatus as shown in FIG. 2.

The present invention will be described in more detail with reference to the following Examples. However, the following examples are merely examples of the present invention, and the claims of the present invention are not limited thereto.

Example 1 Preparation of Chloroethylene Carbonate

Chlorethylene carbonate was produced using the apparatus shown in FIG. 1, and the chloroethylene carbonate prepared from the apparatus of FIG. 1 was purified by the vacuum distillation apparatus shown in FIG. 2.

100 kg (1.136 kmol) of EC (ethylene carbonate) and 200 L of carbon tetrachloride were added to the 500 L G / l reactor 110, and the temperature inside the reactor was maintained at 57 ± 2 ° C. The mixed liquid in the reactor is circulated by three circulation pumps 131, 132, and 133 to the photoreaction unit 120 in which three photoreactors 121, 122, and 123 are connected in parallel. While the yellow mixed solution is introduced into the photoreactor, the chlorine gas is injected through the chlorine gas inlet in front of the photoreactor, but the injection amount is controlled to make the top of the photoreactor transparent. The reaction mixture into which chlorine gas is injected is introduced into the photoreactor and chlorination reaction is performed by light irradiated from the halogen lamp 124 (Philips, 220V, 10A, 500W) provided around the photoreactor. After repeating the circulation process for 48 hours, the reaction was performed through a GC sampler at the bottom of the reactor. As a result, EC was found to be present only 4.3% by weight, and the circulation process was stopped. The reactor was heated under atmospheric pressure to recover carbon tetrachloride in the solvent recovery tanks 151 and 152 through a reflux condenser, and the recovery rate was 80%. After distillation under atmospheric pressure, the mixture was distilled under reduced pressure at 50 ° C. and 5 torr to remove HCl gas and residual carbon tetrachloride, thereby obtaining crude chloroethylene carbonate (crude CEC).

The crude chloroethylene carbonate was transferred to the reduced pressure distillation apparatus shown in FIG. 2, injected into the reactor 210, and distilled under reduced pressure while the reactor was heated at a pressure of 3 torr. 100 kg of chloroethylene carbonate was obtained as a result of obtaining only the material distilled at the reactor temperature of 70 to 80 ° C. (yield 72.15%, purity 99%). No dichloroethylene carbonate was detected in the impurities and 1% ethylene carbonate was present.

Example 2 Preparation of Fluoroethylene Carbonate

Fluoroethylene carbonate was prepared from the chloroethylene carbonate prepared in Example 1 using the production apparatus shown in FIG. 3, and purification of the fluoroethylene carbonate was carried out using the vacuum distillation apparatus shown in FIG. 2.

After making nitrogen atmosphere in 500L reactor 310, DMC 200L and KF 95kg (1.635kmol) as a solvent was added and stirred to maintain the reactor temperature at 10 ± 2 ℃. 150 kg (1.23 kmol) of chloroethylene carbonate prepared in Example 1 was added while maintaining the reactor temperature at 15 ° C. or lower, followed by stirring for 1 hour. The temperature of the reactor was raised to 93 ± 2 ° C. and the reaction was performed for 42 hours, and then the reactor was cooled to room temperature. At this time, the content of the unreacted chloroethylene carbonate as a result of GC was 0.4% by weight. After the reactor is cooled, KCl is removed by filtration under reduced pressure through the filter 320. After filtration was completed, the reactor was heated to 80 ° C., vacuum was gradually collected, and dimethyl carbonate was recovered under reduced pressure to 40 torr. The recovery was 80%. The reactor was further heated to 110 ° C. and monostilled to obtain crude fluoroethylene carbonate.

The crude fluoroethylene carbonate was transferred to the vacuum fractional distillation apparatus shown in FIG. 2, and fractional distillation under reduced pressure at 3 torr, 80 to 100 ° C. yielded 65.2 kg of purified fluoroethylene carbonate. (Yield 50%)

The manufacturing method according to the present invention has the advantage of being suitable for mass production because the material to be used is inexpensive, safe, easy to store and handle, and there is little by-product generation, thus simplifying the purification process. In addition, by using chlorine gas as a material for the chlorination reaction and using a halogen lamp as a light source suitable for its decomposition and selective substitution, there is an advantage that the chlorethylene substituted one chlorethylene carbonate can be selectively produced in high yield. . In addition, by using the chloroethylene carbonate fluorine substitution reaction under a fluorine salt and a solvent there is an advantage that can be produced monofluorinated ethylene carbonate in a higher yield than the conventional production method.

Claims (7)

a) mixing the ethylene carbonate and carbon tetrachloride to prepare a mixed solution; b) a chlorination reaction for injecting chlorine gas into the mixed solution and irradiating with a halogen lamp; c) removing carbon tetrachloride; And d) obtaining chloroethylene carbonate by distillation under reduced pressure; Method for producing chloroethylene carbonate comprising a. The method of claim 1, The chlorination step is a method for producing chloroethylene carbonate, characterized in that to maintain the mixture in the range of 55 to 60 ℃. The method of claim 1, The chlorination step is a method of producing a chloroethylene carbonate, characterized in that through the circulation process of circulating a portion of the mixed solution from the reactor stored in the mixed solution to the photoreactor equipped with a halogen lamp. The method of claim 3, wherein Chlorine gas in the circulation process is characterized in that the chloroethylene carbonate production method characterized in that the injection into the mixed liquid flowing into the reactor. a) preparing a fluorine solution by adding a fluorine salt and a solvent to the reactor; b) injecting chloroethylene carbonate prepared by the method of any one of claims 1 to 4 in the fluoride salt solution; c) heating the reactor to 90 to 95 ° C. for fluorine substitution reaction; And d) cooling the reactor to room temperature and then filtration under reduced pressure to remove the chloride salt and recover the solvent; Method for producing fluoroethylene carbonate comprising a. The method of claim 5, The fluorine salt is potassium chloride, the solvent is dimethyl carbonate, characterized in that the manufacturing method of fluoroethylene carbonate. The method of claim 5, Method for producing fluoroethylene carbonate, characterized in that for maintaining the reactor temperature of step a) and b) at 0 to 15 ℃.

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