Method for recovering catalyst and ethylene carbonate from liquid waste product of ethylene carbonate production

Abstract

A method for recovering a catalyst and ethylene carbonate from a liquid waste product of ethylene carbonate production according to the present invention is characterized by comprising: a step in which a liquid waste product generated in a process for producing ethylene carbonate by reacting ethylene oxide and carbon dioxide in the presence of a metal halide-based catalyst is distilled under reduced pressure to separate and recover ethylene carbonate; a step in which a solid residue remaining after the ethylene carbonate is separated from the liquid waste product is dissolved in dichloromethane and then filtered to remove by-products of the production process; a step in which, after removing the by-products, the filtered solid residue is dissolved in water and then filtered to filter out impurities; and a step for drying the filtrate to recover the metal halide-based catalyst. The recovery method can separate and recover the catalyst and ethylene carbonate at a high yield and purity from the liquid waste product of ethylene carbonate production.

Description

Method for recovering catalyst and ethylene carbonate from ethylene carbonate production waste liquid

[0001] The present invention relates to a method for recovering a catalyst and ethylene carbonate from an ethylene carbonate production waste liquid. More specifically, the present invention relates to a method for separating and recovering a catalyst and ethylene carbonate from an ethylene carbonate production waste liquid with high yield and purity.

[0002]

[0003] Ethylene carbonate is used as a solvent for various chemical reactions, as an electrolyte solvent for lithium-ion secondary batteries, and as a representative raw material for polycarbonate resin.

[0004] Typically, ethylene carbonate is synthesized by reacting ethylene oxide and carbon dioxide at high temperatures and pressures. Various halide-based materials can be used as catalysts during this reaction. Among these, metal halide-based catalysts exhibit excellent reactivity and selectivity, and are therefore widely used.

[0005] During the ethylene carbonate manufacturing process, waste liquid containing ethylene carbonate and catalyst is generated. This waste liquid contains various byproducts. If the waste liquid is recycled directly into the ethylene carbonate manufacturing process, these byproducts could infiltrate the resulting ethylene carbonate, degrading its quality.

[0006] Due to these problems, ethylene carbonate manufacturing waste liquid may be discharged and disposed of by consignment instead of being reused. However, this not only incurs the cost of consignment disposal, but also is not desirable from an economic and environmental perspective because useful substances such as catalysts and ethylene carbonate in the waste liquid are disposed of together.

[0007] Therefore, there is a need to develop a method capable of separating and recovering catalysts and ethylene carbonate with high yield and purity from ethylene carbonate manufacturing wastewater.

[0008] The background technology of the present invention is disclosed in Japanese Patent Publication No. 5762031, etc.

[0009]

[0010] The purpose of the present invention is to provide a method for separating and recovering a catalyst and ethylene carbonate with high yield and high purity from ethylene carbonate production waste liquid.

[0011] The above and other objects of the present invention can all be achieved by the present invention described below.

[0012]

[0013] 1. One aspect of the present invention relates to a method for recovering a catalyst and ethylene carbonate from an ethylene carbonate production waste liquid. The recovery method comprises the steps of: subjecting a production waste liquid generated in a process for producing ethylene carbonate by reacting ethylene oxide and carbon dioxide in the presence of a metal halide catalyst to reduced pressure distillation to separate and recover ethylene carbonate; separating the ethylene carbonate from the production waste liquid, dissolving the remaining solid residue in dichloromethane and filtering the resulting solution to remove by-products of the production process; dissolving the filtered solid residue in water and filtering the resulting solution to remove impurities; and drying the filtrate to recover the metal halide catalyst.

[0014] 2. In the above 1 specific example, the manufacturing waste liquid may include about 1 to about 10 wt% of the metal halide catalyst, about 60 to about 95 wt% of the ethylene carbonate, and about 1 to about 30 wt% of the by-products and impurities, based on 100 wt% of the total manufacturing waste liquid.

[0015] 3. In the above 1 or 2 specific examples, the reduced pressure distillation can be performed under conditions of about 100 to about 150°C and about 0.5 to about 20 torr.

[0016] 4. In the above 1 to 3 specific examples, the separated and recovered ethylene carbonate is dissolved in methanol at a concentration of 5 wt% to prepare a sample, and then the sample is injected into a gas chromatography (GC) equipped with a DB-WAX column at an injection temperature of 250°C, the chamber temperature is maintained at 40°C for 5 minutes, and then the temperature is increased at a rate of 10°C / min to 230°C, and the purity calculated as the area value of the peak detected by a flame ionization detector (FID) may be about 99.5% or more.

[0017] 5. In the above specific examples 1 to 4, the dichloromethane may be added in an amount of about 80 to about 500 parts by weight relative to about 100 parts by weight of the solid residue remaining after separating the ethylene carbonate.

[0018] 6. In the above 1 to 5 specific examples, the water may be added in an amount of about 80 to about 500 parts by weight based on about 100 parts by weight of the solid residue filtered after removing the by-product.

[0019] 7. In the above 1 to 6 specific examples, drying of the filtrate can be performed under conditions of about 60 to about 110°C and about 1 to about 300 torr.

[0020] 8. In the above 1 to 7 specific examples, the recovered metal halide catalyst is dissolved in methanol at a concentration of 5 wt% to prepare a sample, and then the sample is injected into a gas chromatograph equipped with a DB-WAX column at an injection temperature of 250°C, the chamber temperature is maintained at 40°C for 5 minutes, and then the temperature is increased at a rate of 10°C / min to 230°C, and when measured with a flame ionization detector, no organic matter including ethylene carbonate may be detected.

[0021] 9. In the above 1 to 8 specific examples, the recovery method may have a recovery rate of about 70% or more of the metal halide catalyst according to the following formula 1:

[0022] [Formula 1]

[0023] Metal halide catalyst recovery rate (%) = (Amount of recovered metal halide catalyst (g) / Amount of metal halide catalyst in ethylene carbonate manufacturing wastewater (g)) × 100

[0024] In the above formula 1, the amount of metal halide catalyst in the ethylene carbonate manufacturing waste liquid is calculated by multiplying the weight of the manufacturing waste liquid used by the percentage (%) of the content of the metal halide catalyst in the entire manufacturing waste liquid.

[0025]

[0026] The present invention has the effect of providing a method for separating and recovering a catalyst and ethylene carbonate with high yield and high purity from an ethylene carbonate production waste liquid.

[0027]

[0028] Hereinafter, the present invention will be described in detail as follows.

[0029] In this specification, “a to b” indicating a numerical range is defined as “≥a and ≤b”.

[0030]

[0031] The present invention relates to a method for separating and recovering a catalyst and ethylene carbonate with high yield and purity from an ethylene carbonate production waste liquid, comprising the steps of: (A) distilling under reduced pressure a production waste liquid generated in a process for producing ethylene carbonate by reacting ethylene oxide and carbon dioxide in the presence of a metal halide catalyst to separate and recover ethylene carbonate; (B) removing by-products of the production process by dissolving the remaining solid residue in dichloromethane and then filtering the solid residue after removing the by-products; (C) dissolving the filtered solid residue in water and then filtering the solid residue to filter out impurities; and (D) drying the filtrate to recover the metal halide catalyst.

[0032] In a specific example, the manufacturing waste liquid may have the composition of a manufacturing waste liquid generated in a typical ethylene carbonate manufacturing process, and may include, for example, about 1 to about 10 wt% of the metal halide catalyst, about 60 to about 95 wt% of the ethylene carbonate, and about 1 to about 30 wt% of the by-products and impurities, based on 100 wt% of the total manufacturing waste liquid.

[0033] In a specific example, the reduced pressure distillation may be performed at a temperature of about 100 to about 150°C, for example, about 110 to about 145°C, and a pressure of about 0.5 to about 20 torr, for example, about 0.6 to about 10 torr, specifically about 0.7 to about 5 torr, for about 1 to about 6 hours. Within this range, ethylene carbonate can be separated and recovered in a high yield.

[0034] In a specific example, the separated and recovered ethylene carbonate is dissolved in methanol at a concentration of 5 wt% to prepare a sample, and then the sample is injected into a gas chromatograph equipped with a DB-WAX column at an injection temperature of 250°C, the chamber temperature is maintained at 40°C for 5 minutes, and then the temperature is increased at a rate of 10°C / min to 230°C, and the purity calculated as the area value of the peak detected by a flame ionization detector may be about 99.5% or more.

[0035] In a specific example, the dichloromethane may be added in an amount of about 80 to about 500 parts by weight, for example, about 85 to about 300 parts by weight, based on about 100 parts by weight of the solid residue remaining after separating the ethylene carbonate. Within this range, by-products and residual ethylene carbonate, which are highly soluble in dichloromethane, can be dissolved in dichloromethane from the solid residue, and can be effectively removed in a liquid phase through filtration together with the dichloromethane.

[0036] In a specific example, the water may be added in an amount of about 80 to about 500 parts by weight, for example, about 85 to about 300 parts by weight, based on about 100 parts by weight of the solid residue filtered after removing the by-products. In this range, a metal halide catalyst having a high solubility in water can be selectively dissolved in water from the solid residue, and impurities that are not dissolved in water (including residual by-products that are not dissolved in dichloromethane, etc.) can be effectively filtered out through filtration, thereby obtaining a filtrate in which a high-purity metal halide catalyst is dissolved in water.

[0037] In a specific example, the drying of the filtrate may be performed at a temperature of about 60 to about 110°C, for example, about 80 to about 105°C, and a pressure of about 1 to about 300 torr, for example, about 5 to about 40 torr, for about 1 to about 6 hours. Within this range, water can be removed from the filtrate, and a metal halide catalyst can be obtained in high yield and high purity.

[0038] In a specific example, the recovered metal halide catalyst is dissolved in methanol at a concentration of 5 wt% to prepare a sample, and then the sample is injected into a gas chromatograph equipped with a DB-WAX column at an injection temperature of 250°C, the chamber temperature is maintained at 40°C for 5 minutes, and then the temperature is increased to 230°C at a rate of 10°C / min. When measured using a flame ionization detector, no organic matter including ethylene carbonate may be detected.

[0039] In a specific example, the recovery method may have a recovery rate of the metal halide catalyst according to the following formula 1 of about 70% or more, for example, about 80 to about 95%.

[0040] [Formula 1]

[0041] Metal halide catalyst recovery rate (%) = (Amount of recovered metal halide catalyst (g) / Amount of metal halide catalyst in ethylene carbonate manufacturing wastewater (g)) × 100

[0042] In the above formula 1, the amount of metal halide catalyst in the ethylene carbonate manufacturing waste liquid is calculated by multiplying the weight of the manufacturing waste liquid used by the percentage (%) of the content of the metal halide catalyst in the entire manufacturing waste liquid.

[0043]

[0044] In general, since ethylene carbonate acts as a solvent that dissolves the catalyst, if an extraction separation method using a polar solvent and a non-polar solvent is applied without first separating the ethylene carbonate, it is very difficult to completely separate the ethylene carbonate and the catalyst, and the amount of catalyst and ethylene carbonate that can be recovered is reduced because the catalyst is dissolved in both the water layer and the non-polar solvent.

[0045] On the other hand, the catalyst and ethylene carbonate recovery method of the present invention is a method of first separating ethylene carbonate through reduced pressure distillation, and then separating the remaining catalyst and impurities by solubility differences using a non-polar solvent and water. Since there is no residual ethylene carbonate in the step of separating by solubility differences, impurities can be completely removed while recovering a high-purity catalyst.

[0046] As described above, the method for recovering a catalyst and ethylene carbonate from an ethylene carbonate manufacturing waste liquid of the present invention establishes an eco-friendly process for recovering and recycling a catalyst and ethylene carbonate from a manufacturing waste liquid with high yield and high purity, thereby significantly reducing the cost of disposing of the manufacturing waste liquid and the cost of purchasing a catalyst.

[0047]

[0048] Hereinafter, the structure and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, these are presented as preferred examples of the present invention and should not be construed as limiting the present invention in any way.

[0049]

[0050] Example

[0051] Example 1

[0052] 200 g of ethylene carbonate production waste liquid containing 2.3 wt% of an alkali metal halide catalyst, 75.3 wt% of ethylene carbonate (EC), and 22.4 wt% of by-products and impurities was distilled under reduced pressure at 140°C and 1 torr for 4 hours to separate the distillate (ethylene carbonate). The amount of the separated distillate was 147 g, and the distillate was dissolved in methanol at a concentration of 5 wt% to prepare a sample, and the sample was injected into a gas chromatograph (GC, manufacturer: Agilent Technologies, device name: GC 7890A) equipped with a DB-WAX column (manufacturer: Agilent Technologies, product name: J&W DB-WAX, part number: 123-7032) at an injection temperature of 250°C, and the chamber temperature was maintained at 40°C for 5 minutes, and then increased at a rate of 10°C / min to 230°C. The area value of the peak detected by a flame ionization detector was measured to confirm the purity of ethylene carbonate, and as a result, it was confirmed that high-purity ethylene carbonate was recovered at 99.8%.

[0053] Next, ethylene carbonate was separated from the above-mentioned manufacturing waste liquid, and 53 g of the remaining solid residue was mixed with 50 g of dichloromethane (manufactured by: Samchun Pure Chemicals), and stirred for 1 hour to dissolve the solid residue. After that, dichloromethane and dissolved components (by-products of the manufacturing process, etc.) were removed by passing them through a filter paper (manufactured by: ADVANTEC, product name: No. 5C quantitative filter paper), and the solid precipitate filtered on the filter paper was added to 50 g of water (distilled water) and stirred for 30 minutes to dissolve it. Using a filter paper (manufacturer: ADVANTEC, product name: No. 5C quantitative filter paper), the components dissolved in water were passed through, insoluble impurities were removed, and the filtrate (water and alkali metal halide catalyst) was dried at 100°C and 10 torr for 4 hours to obtain 4 g of a white solid (alkali metal halide catalyst). The obtained white solid was dissolved in methanol at a concentration of 5 wt% to prepare a sample, and the sample was analyzed using a gas chromatograph (GC, manufacturer: Agilent Technologies, equipment name: GC 7890A) equipped with a DB-WAX column (manufacturer: Agilent Technologies, product name: J&W DB-WAX, product number: 123-7032), and it was confirmed that no organic substances including ethylene carbonate were detected. In addition, the contents of alkali metal and halide components were analyzed using an inductively coupled plasma optical spectroscopy (ICP-OES, manufacturer: Perkin-Elmer, product name: OPTIMA 7300DV) and an ion chromatography (IC, manufacturer: Thermo Fisher Scientific, product name: ICS-6000, combustion device: AQF-2100H (manufacturer: Mitsubishi Chemical Corporation)), and it was confirmed that the alkali metal halide catalyst was normally recovered. According to the following equation 1, the recovery rate of the alkali metal halide catalyst was calculated, and the results are shown in Table 1.

[0054]

[0055] Comparative Example 1

[0056] 200 g of ethylene carbonate manufacturing waste liquid was mixed with 360 g of water and 40 g of dichloromethane, stirred for 30 minutes, and allowed to stand. As a result, it was confirmed that layers were separated into a water (polar solvent) layer and a dichloromethane (non-polar solvent) layer. The water layer was separated and dried at 100°C and 10 torr for 4 hours, but it still existed in a liquid state and weighed 110.4 g. As a result of gas chromatography, inductively coupled plasma spectrometry, and ion chromatography analysis, ethylene carbonate was confirmed to be 96.6 wt%, and an alkali metal halide catalyst was confirmed to be 3.4 wt%, indicating that a large amount of ethylene carbonate still remained without being separated. The recovery rate of the alkali metal halide catalyst was calculated according to Equation 1 below, and the results are shown in Table 1.

[0057]

[0058] Comparative Example 2

[0059] The same procedure as in Comparative Example 1 was followed, except that 200 g of water and 200 g of dichloromethane were mixed with 200 g of ethylene carbonate manufacturing wastewater. The aqueous layer was separated and dried at 100°C and 10 torr for 4 hours, but it still existed in a liquid state and weighed 47.8 g. As a result of gas chromatography, inductively coupled plasma spectrometry, and ion chromatography analysis, ethylene carbonate was confirmed to be 93.3 wt%, and the alkali metal halide catalyst was 6.7 wt%, indicating that a large amount of ethylene carbonate still remained without being separated. The recovery rate of the alkali metal halide catalyst was calculated according to Equation 1 below, and the results are shown in Table 1.

[0060]

[0061] Comparative Example 3

[0062] The same procedure as in Comparative Example 1 was followed, except that 40 g of water and 360 g of dichloromethane were mixed with 200 g of ethylene carbonate manufacturing wastewater. The aqueous layer was separated and dried at 100°C and 10 torr for 4 hours, but it still existed in a liquid state and weighed 12.4 g. As a result of gas chromatography, inductively coupled plasma spectrometry, and ion chromatography analysis, ethylene carbonate was confirmed to be 85.1 wt%, and the alkali metal halide catalyst was 14.9 wt%, indicating that a large amount of ethylene carbonate still remained without being separated. The recovery rate of the alkali metal halide catalyst was calculated according to Equation 1 below, and the results are shown in Table 1.

[0063]

[0064] Comparative Example 4

[0065] After performing the same procedure as in Comparative Example 3, the aqueous layer was separated and distilled under reduced pressure for 4 hours at 140°C and 1 torr, but the solid and liquid phases were mixed and the weight was 2.3 g. As a result of gas chromatography, inductively coupled plasma spectrometry, and ion chromatography analysis, ethylene carbonate was confirmed to be 21.5 wt% and the alkali metal halide catalyst was 78.5 wt%, indicating that although the catalyst content was high, a large amount of ethylene carbonate still remained without being separated. According to Equation 1 below, the recovery rate of the alkali metal halide catalyst was calculated, and the results are shown in Table 1.

[0066]

[0067] Method of measuring physical properties

[0068] Recovery rate of metal halide catalyst (unit: %): The recovery rate of metal halide catalyst was calculated according to Equation 1 below.

[0069] [Formula 1]

[0070] Metal halide catalyst recovery rate (%) = (Amount of recovered metal halide catalyst (g) / Amount of metal halide catalyst in ethylene carbonate manufacturing wastewater (g)) × 100

[0071] In the above formula 1, the amount of metal halide catalyst in the ethylene carbonate manufacturing waste liquid is calculated by multiplying the weight of the manufacturing waste liquid used by the percentage (%) of the content of the metal halide catalyst in the entire manufacturing waste liquid.

[0072] For reference, the amount of recovered alkali metal halide catalyst of Comparative Examples 1 to 4 was calculated from the contents of gas chromatography, inductively coupled plasma spectrometry, and ion chromatography analysis results of the liquid phase or liquid and solid phase mixed phase results obtained in Comparative Examples 1 to 4.

[0073]

[0074] Example Comparative Example 11234 Recovery result weight (g) 4.0 1 10.4 4 7.8 12.4 2.3 Catalyst content (wt%) 100 3.4 6.7 14.9 7 8.5 EC content (wt%) 0 96.6 9 3.3 8 5.1 2 1.5 Catalyst recovery rate (%) 87.0 8 1.6 6 9.6 4 0.2 3 9.3

[0075]

[0076] From the above results, it can be seen that the method of recovering a catalyst and ethylene carbonate from an ethylene carbonate production waste liquid of the present invention first separates and recovers ethylene carbonate from the production waste liquid by reduced pressure distillation, and then separates and recovers a metal halide catalyst, thereby enabling separation and recovery of the catalyst and ethylene carbonate with high yield and high purity.

[0077] On the other hand, in the case of the comparative example in which ethylene carbonate was not separated and recovered first, it can be seen that an excessive amount of unseparated ethylene carbonate remains together with dichloromethane in the resultant product, and the recovery rate of the metal halide catalyst is also reduced.

[0078]

[0079] The present invention has been described with reference to exemplary embodiments. Those skilled in the art will appreciate that the present invention can be implemented in modified forms without departing from its essential characteristics. Therefore, the disclosed embodiments should be considered illustrative rather than limiting. The scope of the present invention is set forth in the claims, not the foregoing description, and all differences within the scope equivalent thereto should be construed as being encompassed by the present invention.

Claims

1. In a process of manufacturing ethylene carbonate by reacting ethylene oxide and carbon dioxide in the presence of a metal halide catalyst, the manufacturing waste liquid generated is distilled under reduced pressure to separate and recover ethylene carbonate; The ethylene carbonate is separated from the above manufacturing waste liquid, and the remaining solid residue is dissolved in dichloromethane and filtered to remove the by-products of the manufacturing process; After removing the above by-products, the filtered solid residue is dissolved in water and filtered to filter out impurities; and A method for recovering a catalyst and ethylene carbonate from an ethylene carbonate production waste liquid, characterized in that it comprises a step of drying the filtrate to recover a metal halide catalyst.

2. A method for recovering a catalyst and ethylene carbonate from an ethylene carbonate production waste liquid, characterized in that the production waste liquid comprises about 1 to about 10 wt% of the metal halide catalyst, about 60 to about 95 wt% of the ethylene carbonate, and about 1 to about 30 wt% of the by-products and impurities, based on 100 wt% of the total production waste liquid.

3. A method for recovering a catalyst and ethylene carbonate from an ethylene carbonate production waste liquid, characterized in that the reduced pressure distillation in claim 1 or 2 is performed under conditions of about 100 to about 150°C and about 0.5 to about 20 torr.

4. A method for recovering a catalyst and ethylene carbonate from an ethylene carbonate production waste liquid, characterized in that the purity calculated from the area value of a peak detected by a flame ionization detector under the condition that the separated and recovered ethylene carbonate is dissolved in methanol at a concentration of 5 wt% to prepare a sample, the sample is injected into a gas chromatograph equipped with a DB-WAX column at an injection temperature of 250°C, the chamber temperature is maintained at 40°C for 5 minutes, and then the temperature is increased to 230°C at a rate of 10°C / min in any one of the preceding claims, is about 99.5% or more.

5. A method for recovering a catalyst and ethylene carbonate from an ethylene carbonate production waste liquid, characterized in that the dichloromethane is added in an amount of about 80 to about 500 parts by weight based on about 100 parts by weight of the solid residue remaining after separating the ethylene carbonate, in any one of the preceding claims.

6. A method for recovering a catalyst and ethylene carbonate from an ethylene carbonate production waste liquid, characterized in that the water is added in an amount of about 80 to about 500 parts by weight based on about 100 parts by weight of the solid residue filtered after removing the by-products in any one of the first to fifth clauses.

7. A method for recovering a catalyst and ethylene carbonate from an ethylene carbonate production waste liquid, characterized in that the drying of the filtrate is performed under conditions of about 60 to about 110°C and about 1 to about 300 torr in any one of claims 1 to 6.

8. A method for recovering a catalyst and ethylene carbonate from an ethylene carbonate production waste liquid, characterized in that, in any one of claims 1 to 7, the recovered metal halide catalyst is dissolved in methanol at a concentration of 5 wt% to prepare a sample, the sample is injected into a gas chromatograph equipped with a DB-WAX column at an injection temperature of 250°C, the chamber temperature is maintained at 40°C for 5 minutes, and then the temperature is increased to 230°C at a rate of 10°C / min, when measured with a flame ionization detector, no organic matter including ethylene carbonate is detected.

9. A method for recovering a catalyst and ethylene carbonate from an ethylene carbonate production waste liquid, characterized in that the recovery rate of the metal halide catalyst according to the following formula 1 is about 70% or more, in any one of paragraphs 1 to 8: [Formula 1] Metal halide catalyst recovery rate (%) = (Amount of recovered metal halide catalyst (g) / Amount of metal halide catalyst in ethylene carbonate manufacturing wastewater (g)) × 100 In the above formula 1, the amount of metal halide catalyst in the ethylene carbonate manufacturing waste liquid is calculated by multiplying the weight of the manufacturing waste liquid used by the percentage (%) of the content of the metal halide catalyst in the entire manufacturing waste liquid.