A method for separating ethylene carbonate and chloroethylene carbonate

Abstract

This invention provides a method for separating ethylene carbonate and chloroethylene carbonate. The method includes: mixing a first mixture containing ethylene carbonate and chloroethylene carbonate with a substituted halobenzene compound, performing a first separation to obtain ethylene carbonate and a second mixture containing chloroethylene carbonate, respectively. By adding a substituted halobenzene compound, this invention increases the relative volatility of ethylene carbonate and chloroethylene carbonate, reduces the difficulty of their separation, decreases the theoretical plate number, and reduces energy consumption. Furthermore, the ethylene carbonate after the first separation has high purity, overcoming the bottleneck of conventional separation methods in obtaining high-purity ethylene carbonate and chloroethylene carbonate.

Description

Technical Field

[0001] This invention belongs to the field of chemical separation technology and relates to a method for separating ethylene carbonate and chloroethylene carbonate. Background Technology

[0002] Ethylene carbonate (EC) is an important organic compound with wide applications in chemical, pharmaceutical, and electronics industries. Its primary use is as a solvent in lithium-ion battery electrolytes, due to its high dielectric constant and polarizability, which improves battery capacity and cycle life. Additionally, ethylene carbonate can be used to prepare chloroethylene carbonate (CEC), a key raw material for the preparation of electrolyte additives such as vinylene carbonate (VC) and fluoroethylene carbonate (FEC).

[0003] Currently, industrially, CEC is prepared by reacting EC with chlorine. During the reaction, the higher the EC conversion rate, the higher the proportion of the byproduct dichloroethylene carbonate (DCEC). To reduce DCEC formation, the EC conversion rate is typically controlled. Industrial production usually maintains a CEC concentration of 60%-85%, with the remainder being mainly EC and a small amount of DCEC. When using 60%-85% CEC to prepare VC and FEC, EC, as a heavy component, remains in the bottom of the separation column and is discharged along with tar as heavy waste. This process wastes EC and increases hazardous waste treatment costs. Separating and recovering EC from the 60%-85% CEC feedstock allows the recovered EC to be reused as a feedstock for further CEC production with chlorine, reducing both raw material waste and hazardous waste generation and treatment costs.

[0004] EC and CEC have similar boiling points (EC: 243℃, CEC: 237℃), making their separation and purification extremely difficult. Traditional distillation methods require a very high number of trays and extremely high reflux ratios, resulting in very high energy consumption. Effective separation of EC and CEC to obtain high-purity products would enable EC recovery and reuse, reducing production costs and effectively improving both economic and environmental benefits for enterprises. However, currently, there is no efficient and low-cost method for separating EC and CEC in the industry.

[0005] Therefore, providing a simple, low-cost method for separating EC and CEC with high product purity is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a method for separating ethylene carbonate and chloroethylene carbonate. By adding a substituted halobenzene compound, the relative volatility of ethylene carbonate and chloroethylene carbonate is increased, and efficient separation of the two is achieved through a first separation process.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] This invention provides a method for separating ethylene carbonate and chloroethylene carbonate, the separation method comprising:

[0009] A first mixture containing ethylene carbonate and chloroethylene carbonate is mixed with a substituted halobenzene compound and subjected to a first separation to obtain ethylene carbonate and a second mixture containing chloroethylene carbonate, respectively.

[0010] The separation method provided by this invention increases the relative volatility of ethylene carbonate and chloroethylene carbonate by adding substituted halobenzene compounds, thereby reducing the difficulty of separating the two, reducing the number of theoretical plates, reducing energy consumption, and producing high purity ethylene carbonate after the first separation. This method overcomes the bottleneck of conventional separation methods in obtaining high-purity ethylene carbonate and chloroethylene carbonate.

[0011] As a preferred embodiment of the present invention, the substituted halobenzene compound includes alkyl-substituted halobenzene.

[0012] Preferably, the number of alkyl groups in the alkyl-substituted halobenzene includes 1 to 5, for example, 1, 2, 3, 4 or 5, preferably 2.

[0013] Preferably, the alkyl group in the alkyl-substituted halobenzene includes a straight-chain or branched alkyl group of C1-C6, preferably methyl, wherein "C1-C6" refers to a carbon number of 1-6, for example, 1, 2, 3, 4, 5 or 6.

[0014] Preferably, the alkyl-substituted halobenzene compound includes any one or a combination of at least two of alkyl-substituted chlorobenzene, alkyl-substituted bromobenzene, or alkyl-substituted iodobenzene.

[0015] In this invention, taking dimethyl-substituted chlorobenzene as an example, the dimethyl-substituted chlorobenzene includes any one or a combination of at least two of 2,3-dimethylchlorobenzene, 2,4-dimethylchlorobenzene, 2,5-dimethylchlorobenzene, 2,6-dimethylchlorobenzene, 3,4-dimethylchlorobenzene, or 3,5-dimethylchlorobenzene.

[0016] As a preferred embodiment of the present invention, the first mixture comprises a chlorination reaction solution of ethylene carbonate.

[0017] In this invention, the chlorination reaction solution of ethylene carbonate includes crude chloroethylene carbonate with a purity of 60-85%.

[0018] Preferably, the mass ratio of ethylene carbonate to chloroethylene carbonate in the first mixture is (0.1-10):1, for example, it can be 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1 or 9:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0019] As a preferred technical solution of the present invention, the mass ratio of the substituted halobenzene compound and the first mixture is (0.01-0.5):1, for example, it can be 0.05:1, 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1 or 0.45:1, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably (0.1-0.3):1.

[0020] As a preferred technical solution of the present invention, the first separation includes supergravity distillation.

[0021] It is worth noting that the first separation method of this invention adopts supergravity distillation, which enhances mass transfer and enables efficient separation of ethylene carbonate and chloroethylene carbonate.

[0022] Preferably, the vacuum degree of the supergravity distillation is 0.1-10 kPaA, for example, it can be 0.5 kPaA, 1 kPaA, 2 kPaA, 3 kPaA, 4 kPaA, 5 kPaA, 6 kPaA, 7 kPaA, 8 kPaA or 9 kPaA, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0023] Preferably, the rotational speed of the supergravity distillation is 500-2000 rpm, for example, it can be 600 rpm, 800 rpm, 1000 rpm, 1200 rpm, 1500 rpm, 1600 rpm or 1800 rpm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] As a preferred technical solution of the present invention, the supergravity distillation is carried out using a supergravity distillation apparatus.

[0025] In this invention, the ethylene carbonate is collected from the reboiler at the bottom of the centrifugal distillation apparatus, and the second mixture containing chlorinated ethylene carbonate is collected from the top of the centrifugal distillation apparatus.

[0026] Preferably, the rotor packing inside the supergravity distillation apparatus includes corrugated structured packing.

[0027] Preferably, the corrugated structured packing has an inner diameter of 100-300 mm, an outer diameter of 200-1000 mm, and a height of 200-500 mm.

[0028] In this invention, the inner diameter of the corrugated structured packing is 100-300mm, for example, it can be 120mm, 150mm, 180mm, 200mm, 220mm, 250mm or 280mm, etc.; the outer diameter is 200-1000mm, for example, it can be 300mm, 400mm, 500mm, 600mm, 700mm, 800mm or 900mm, etc.; and the height is 200-500mm, for example, it can be 220mm, 250mm, 280mm, 300mm, 350mm, 400mm or 450mm, etc., but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0029] Preferably, the corrugated structured packing includes any one or a combination of at least two of silicon carbide corrugated structured packing, perforated plate corrugated structured packing, ceramic corrugated structured packing, or metal wire mesh corrugated structured packing. Typical but not limited combinations include: a combination of silicon carbide corrugated structured packing and perforated plate corrugated structured packing, a combination of ceramic corrugated structured packing and metal wire mesh corrugated structured packing, or a combination of metal wire mesh corrugated structured packing and silicon carbide corrugated structured packing, etc., with ceramic corrugated structured packing being the most preferred.

[0030] In this invention, the material of the perforated plate corrugated packing includes plastic or metal.

[0031] As a preferred embodiment of the present invention, the first separation further includes: performing a second separation on the second mixture to obtain chloroethylene carbonate and substituted halobenzene compounds, wherein the obtained substituted halobenzene compounds are reused in the first separation.

[0032] In this invention, the substituted halobenzene compound can be recycled, avoiding the generation of waste and reducing production costs.

[0033] As a preferred technical solution of the present invention, the second separation method includes distillation or crystallization, preferably distillation.

[0034] As a preferred embodiment of the present invention, the distillation is carried out using a plate distillation column.

[0035] In this invention, the chloroethylene carbonate is collected from the bottom of the plate distillation column, and the substituted halobenzene compound is collected from the top of the plate distillation column.

[0036] Preferably, the number of trays in the plate distillation column is 10-50, for example, 15, 20, 25, 30, 35, 40 or 45, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0037] Preferably, the vacuum degree of the plate distillation column is 0.5-20 kPaA, for example, it can be 1 kPaA, 3 kPaA, 5 kPaA, 6 kPaA, 8 kPaA, 10 kPaA, 12 kPaA, 15 kPaA, 16 kPaA or 18 kPaA, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0038] Preferably, the reflux ratio of the plate distillation column is (0.1-10):1, for example, it can be 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1 or 9:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0039] Preferably, the bottom temperature of the plate distillation column is 80-160℃, for example, it can be 90℃, 100℃, 110℃, 120℃, 130℃, 140℃ or 150℃, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0040] As a preferred technical solution of the present invention, the separation method includes the following steps:

[0041] (1) The first mixture containing ethylene carbonate and chloroethylene carbonate is mixed with a substituted halobenzene compound and subjected to a first separation to obtain ethylene carbonate and a second mixture containing chloroethylene carbonate, respectively.

[0042] The substituted halobenzene compound includes alkyl-substituted halobenzene; the number of alkyl groups in the alkyl-substituted halobenzene is 1-5; the alkyl groups in the alkyl-substituted halobenzene include C1-C6 straight-chain or branched alkyl groups; the alkyl-substituted halobenzene compound includes any one or a combination of at least two of alkyl-substituted chlorobenzene, alkyl-substituted bromobenzene, or alkyl-substituted iodobenzene.

[0043] The first mixture includes a chlorinated ethylene carbonate reaction solution; the mass ratio of ethylene carbonate to chloroethylene carbonate in the first mixture is (0.1-10):1; the mass ratio of the substituted halobenzene compound to the first mixture is (0.01-0.5):1;

[0044] The first separation includes high gravity distillation; the high gravity distillation is carried out under a vacuum of 0.1-10 kPaA and a rotation speed of 500-2000 rpm.

[0045] (2) The second mixture from step (1) is subjected to a second separation to obtain vinyl chloride carbonate and substituted halobenzene compound, respectively. The substituted halobenzene compound is recycled into the first separation.

[0046] The second separation method includes distillation or crystallization.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] (1) The separation method provided by the present invention increases the relative volatility of ethylene carbonate and chloroethylene carbonate by adding substituted halobenzene compounds, thereby reducing the difficulty of separating the two. Combined with the first separation method using supergravity distillation, the enhanced mass transfer effect of supergravity distillation enables the efficient separation of ethylene carbonate and chloroethylene carbonate. The separated products have high purity, with the ethylene carbonate purity ≥99.9% and the chloroethylene carbonate purity ≥99.9%. This method breaks through the bottleneck of conventional separation methods being unable to obtain high-purity ethylene carbonate and chloroethylene carbonate, realizes the recycling of ethylene carbonate, and avoids the waste of resources.

[0049] (2) The separation method provided by the present invention has strong operability, mild and stable process, reduces the theoretical number of distillation columns, has low energy consumption, and can replace halogenated compounds for recycling, avoiding the generation of waste and reducing production costs. Detailed Implementation

[0050] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0051] Example 1

[0052] This embodiment provides a method for separating ethylene carbonate and chloroethylene carbonate, the separation method comprising the following steps:

[0053] (1) The first mixture containing ethylene carbonate and chloroethylene carbonate is mixed with 2,3-dimethylchlorobenzene and subjected to first separation by a supergravity distillation apparatus. Ethyl carbonate is obtained at the bottom of the column and chloroethylene carbonate is obtained at the top of the column.

[0054] The first mixture is a chlorination reaction solution of ethylene carbonate, and the mass ratio of ethylene carbonate to chloroethylene carbonate in the first mixture is 0.5:1; the mass ratio of 2,3-dimethylchlorobenzene to the first mixture is 0.15:1.

[0055] The vacuum degree of the first separation (hypergravity distillation) is 0.5 kPaA, and the rotation speed is 1000 rpm; the rotor packing inside the hypergravity distillation device is ceramic corrugated structured packing; the inner diameter of the ceramic corrugated structured packing is 200 mm, the outer diameter is 800 mm, and the height is 300 mm.

[0056] (2) In step (1), the second mixture is subjected to a second separation in a plate distillation column. The bottom of the column yields chloroethylene carbonate, and the 2,3-dimethylchlorobenzene obtained at the top of the column is recycled in step (1).

[0057] The plate distillation column has 25 trays, a vacuum of 2 kPaA, a reflux ratio of 3:1, and a bottom temperature of 130°C.

[0058] Example 2

[0059] This embodiment provides a method for separating ethylene carbonate and chloroethylene carbonate, the separation method comprising the following steps:

[0060] (1) The first mixture containing ethylene carbonate and chloroethylene carbonate is mixed with 2,4-dimethylchlorobenzene and subjected to first separation by a supergravity distillation apparatus. Ethyl carbonate is obtained at the bottom of the column and chloroethylene carbonate is obtained at the top of the column.

[0061] The first mixture is a chlorination reaction solution of ethylene carbonate, and the mass ratio of ethylene carbonate to chloroethylene carbonate in the first mixture is 0.1:1; the mass ratio of 2,4-dimethylchlorobenzene to the first mixture is 0.2:1.

[0062] The vacuum degree of the first separation (hypergravity distillation) is 5 kPaA and the rotation speed is 500 rpm; the rotor packing inside the hypergravity distillation device is silicon carbide corrugated structured packing; the inner diameter of the silicon carbide corrugated structured packing is 250 mm, the outer diameter is 1000 mm, and the height is 200 mm.

[0063] (2) In step (1), the second mixture is subjected to a second separation in a plate distillation column. The bottom of the column yields chloroethylene carbonate, and the 2,4-dimethylchlorobenzene obtained at the top of the column is recycled in step (1).

[0064] The plate distillation column has 35 plates, a vacuum of 0.5 kPaA, a reflux ratio of 1:1, and a bottom temperature of 80°C.

[0065] Example 3

[0066] This embodiment provides a method for separating ethylene carbonate and chloroethylene carbonate, the separation method comprising the following steps:

[0067] (1) The first mixture containing ethylene carbonate and chloroethylene carbonate is mixed with 2,5-dimethylchlorobenzene and subjected to first separation by a supergravity distillation apparatus. Ethyl carbonate is obtained at the bottom of the column and chloroethylene carbonate is obtained at the top of the column.

[0068] The first mixture is a chlorination reaction solution of ethylene carbonate, and the mass ratio of ethylene carbonate to chloroethylene carbonate in the first mixture is 1:1; the mass ratio of 2,5-dimethylchlorobenzene to the first mixture is 0.1:1.

[0069] The vacuum degree of the first separation (hypergravity distillation) is 0.1 kPaA, and the rotation speed is 800 rpm; the rotor packing inside the hypergravity distillation device is ceramic corrugated structured packing; the inner diameter of the ceramic corrugated structured packing is 100 mm, the outer diameter is 200 mm, and the height is 500 mm.

[0070] (2) In step (1), the second mixture is subjected to a second separation in a plate distillation column. The bottom of the column yields chloroethylene carbonate, and the 2,5-dimethylchlorobenzene obtained at the top of the column is recycled in step (1).

[0071] The plate distillation column has 10 plates, a vacuum of 5 kPaA, a reflux ratio of 10:1, and a bottom temperature of 110°C.

[0072] Example 4

[0073] This embodiment provides a method for separating ethylene carbonate and chloroethylene carbonate, the separation method comprising the following steps:

[0074] (1) The first mixture containing ethylene carbonate and chloroethylene carbonate is mixed with 2,6-dimethylchlorobenzene and subjected to first separation by a supergravity distillation apparatus. Ethyl carbonate is obtained at the bottom of the column and chloroethylene carbonate is obtained at the top of the column.

[0075] The first mixture is a chlorination reaction solution of ethylene carbonate, and the mass ratio of ethylene carbonate to chloroethylene carbonate in the first mixture is 10:1; the mass ratio of 2,6-dimethylchlorobenzene to the first mixture is 0.3:1.

[0076] The vacuum degree of the first separation (hypergravity distillation) is 10 kPaA and the rotation speed is 2000 rpm; the rotor packing inside the hypergravity distillation device is perforated corrugated structured packing; the inner diameter of the perforated corrugated structured packing is 150 mm, the outer diameter is 500 mm, and the height is 250 mm.

[0077] (2) In step (1), the second mixture is subjected to a second separation in a plate distillation column. The bottom of the column yields chloroethylene carbonate, and the 2,6-dimethylchlorobenzene obtained at the top of the column is recycled in step (1).

[0078] The plate distillation column has 20 trays, a vacuum of 15 kPaA, a reflux ratio of 6:1, and a bottom temperature of 160°C.

[0079] Example 5

[0080] This embodiment provides a method for separating ethylene carbonate and chloroethylene carbonate, the separation method comprising the following steps:

[0081] (1) The first mixture containing ethylene carbonate and chloroethylene carbonate is mixed with 3,4-dimethylchlorobenzene and subjected to first separation by a supergravity distillation apparatus. Ethyl carbonate is obtained at the bottom of the column and chloroethylene carbonate is obtained at the top of the column.

[0082] The first mixture is a chlorination reaction solution of ethylene carbonate, and the mass ratio of ethylene carbonate to chloroethylene carbonate in the first mixture is 4:1; the mass ratio of 3,4-dimethylchlorobenzene to the first mixture is 0.25:1.

[0083] The vacuum degree of the first separation (hypergravity distillation) is 1 kPaA, and the rotation speed is 1300 rpm; the rotor packing inside the hypergravity distillation device is ceramic corrugated structured packing; the inner diameter of the ceramic corrugated structured packing is 300 mm, the outer diameter is 1000 mm, and the height is 400 mm.

[0084] (2) In step (1), the second mixture is subjected to a second separation in a plate distillation column. The bottom of the column yields chloroethylene carbonate, and the 3,4-dimethylchlorobenzene obtained at the top of the column is recycled in step (1).

[0085] The plate distillation column has 50 plates, a vacuum of 10 kPaA, a reflux ratio of 0.1:1, and a bottom temperature of 150°C.

[0086] Example 6

[0087] This embodiment provides a method for separating ethylene carbonate and chloroethylene carbonate, the separation method comprising the following steps:

[0088] (1) The first mixture containing ethylene carbonate and chloroethylene carbonate is mixed with 3,5-dimethylchlorobenzene and subjected to first separation by a supergravity distillation apparatus. Ethyl carbonate is obtained at the bottom of the column and chloroethylene carbonate is obtained at the top of the column.

[0089] The first mixture is a chlorination reaction solution of ethylene carbonate, and the mass ratio of ethylene carbonate to chloroethylene carbonate in the first mixture is 7:1; the mass ratio of 3,5-dimethylchlorobenzene to the first mixture is 0.2:1.

[0090] The first separation (hypergravity distillation) has a vacuum of 7 kPaA and a rotation speed of 1500 rpm; the rotor packing inside the hypergravity distillation device is a metal wire mesh corrugated structured packing; the inner diameter of the metal wire mesh corrugated structured packing is 200 mm, the outer diameter is 600 mm, and the height is 300 mm.

[0091] (2) In step (1), the second mixture is subjected to a second separation in a plate distillation column. The bottom of the column yields chloroethylene carbonate, and the 3,5-dimethylchlorobenzene obtained at the top of the column is recycled in step (1).

[0092] The plate distillation column has 40 plates, a vacuum of 20 kPaA, a reflux ratio of 0.5:1, and a bottom temperature of 160°C.

[0093] Example 7

[0094] This embodiment provides a method for separating ethylene carbonate and chloroethylene carbonate. Except for replacing "2,3-dimethylchlorobenzene" with 4-methylchlorobenzene, all other conditions are the same as in Example 1.

[0095] Example 8

[0096] This embodiment provides a method for separating ethylene carbonate and chloroethylene carbonate. Except for adjusting the mass ratio of 2,3-dimethylchlorobenzene to the first mixture from 0.15:1 to 1:1 while keeping the content of the first mixture unchanged, all other conditions are the same as in Example 1.

[0097] Example 9

[0098] This embodiment provides a method for separating ethylene carbonate and chloroethylene carbonate. Except for adjusting the mass ratio of 2,3-dimethylchlorobenzene to the first mixture from 0.15:1 to 0.001:1 while keeping the content of the first mixture unchanged, all other conditions are the same as in Example 1.

[0099] Example 10

[0100] This embodiment provides a method for separating ethylene carbonate and chloroethylene carbonate. Except for the first separation being changed from centrifugal distillation to plate distillation, all other conditions are the same as in Example 1.

[0101] Comparative Example 1

[0102] This comparative example provides a method for separating ethylene carbonate and chloroethylene carbonate, except that "2,3-dimethylchlorobenzene" is replaced with chlorobenzene, and all other conditions are the same as in Example 1.

[0103] Comparative Example 2

[0104] This comparative example provides a method for separating ethylene carbonate and chloroethylene carbonate, with all conditions being the same as in Example 1 except that 2,3-dimethylchlorobenzene was not added.

[0105] The purity of the extracted fluids from the above embodiments and comparative examples was tested using gas chromatography, and the test results are shown in Table 1.

[0106] Table 1

[0107]

[0108]

[0109] As shown in Table 1:

[0110] (1) The separation method provided in Examples 1-7 of the present invention increases the relative volatility of ethylene carbonate and chloroethylene carbonate by adding substituted halobenzene compounds, and achieves efficient separation of ethylene carbonate and chloroethylene carbonate by using supergravity distillation in conjunction with the first separation, and the substituted halobenzene compounds can be recycled; wherein, the purity of the separated ethylene carbonate is ≥99.9%, the purity of the chloroethylene carbonate is ≥99.9%, and when the substituted halobenzene compound is preferably dimethyl-substituted halobenzene, the purity of the separated ethylene carbonate is ≥99.95%, and the purity of the chloroethylene carbonate is >99.99%;

[0111] (2) Comparison of Examples 1 and 8-9 shows that the best effect is achieved when the mass ratio of the substituted halobenzene compound to the first mixture is controlled within (0.01-0.5):1. Adding too much or too little substituted halobenzene compound will have an adverse effect on the separation of EC and CEC.

[0112] (3) A comparison of Examples 1 and 10 and Comparative Examples 1-2 shows that neither adding substituted halobenzene compounds under centrifugal distillation conditions nor using centrifugal distillation without adding substituted halobenzene compounds can effectively solve the problem of separating EC and CEC. Only a combination of both methods can achieve a good separation effect, ensuring that the purity of the separated ethylene carbonate is ≥99.9% and the purity of the chloroethylene carbonate is ≥99.9%.

[0113] The applicant declares that the detailed structural features of the present invention are illustrated through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components selected in the present invention, additions of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for separating ethylene carbonate and chloroethylene carbonate, characterized in that, The separation method includes: A first mixture containing ethylene carbonate and chloroethylene carbonate is mixed with a substituted halobenzene compound and subjected to a first separation to obtain ethylene carbonate and a second mixture containing chloroethylene carbonate, respectively. The substituted halobenzene compound is an alkyl-substituted halobenzene; the number of alkyl groups in the alkyl-substituted halobenzene is 1-5; the alkyl groups in the alkyl-substituted halobenzene are C1-C6 straight-chain or branched alkyl groups.

2. The separation method according to claim 1, characterized in that, The number of alkyl groups in the alkyl-substituted halobenzene is two.

3. The separation method according to claim 1, characterized in that, The alkyl group in the alkyl-substituted halobenzene is methyl.

4. The separation method according to claim 1, characterized in that, The alkyl-substituted halobenzene compound is any one or a combination of at least two of alkyl-substituted chlorobenzene, alkyl-substituted bromobenzene, or alkyl-substituted iodobenzene.

5. The separation method according to claim 1, characterized in that, The first mixture is a chlorination reaction solution of ethylene carbonate.

6. The separation method according to claim 1, characterized in that, The mass ratio of ethylene carbonate to chloroethylene carbonate in the first mixture is (0.1-10):

1.

7. The separation method according to claim 1, characterized in that, The mass ratio of the substituted halobenzene compound to the first mixture is (0.01-0.5):

1.

8. The separation method according to claim 7, characterized in that, The mass ratio of the substituted halobenzene compound to the first mixture is (0.1-0.3):

1.

9. The separation method according to claim 1, characterized in that, The first separation is a supergravity distillation.

10. The separation method according to claim 9, characterized in that, The vacuum degree of the supergravity distillation is 0.1-10 kPaA.

11. The separation method according to claim 9, characterized in that, The rotational speed of the supergravity distillation is 500-2000 rpm.

12. The separation method according to claim 9, characterized in that, The supergravity distillation is carried out using a supergravity distillation apparatus.

13. The separation method according to claim 12, characterized in that, The rotor packing inside the supergravity distillation device is corrugated structured packing.

14. The separation method according to claim 13, characterized in that, The corrugated structured packing has an inner diameter of 100-300 mm, an outer diameter of 200-1000 mm, and a height of 200-500 mm.

15. The separation method according to claim 13, characterized in that, The corrugated structured packing is any one or a combination of at least two of the following: silicon carbide corrugated structured packing, perforated plate corrugated structured packing, ceramic corrugated structured packing, or metal wire mesh corrugated structured packing.

16. The separation method according to claim 15, characterized in that, The corrugated structured packing is a ceramic corrugated structured packing.

17. The separation method according to claim 1, characterized in that, The process further includes: performing a second separation on the second mixture to obtain chloroethylene carbonate and substituted halobenzene compounds, respectively, with the obtained substituted halobenzene compounds being reused in the first separation.

18. The separation method according to claim 17, characterized in that, The second separation method is distillation or crystallization.

19. The separation method according to claim 18, characterized in that, The second separation method is distillation.

20. The separation method according to claim 18, characterized in that, The distillation is carried out using a plate distillation column.

21. The separation method according to claim 20, characterized in that, The number of trays in the plate distillation column is 10-50.

22. The separation method according to claim 20, characterized in that, The vacuum degree of the plate distillation column is 0.5-20 kPaA.

23. The separation method according to claim 20, characterized in that, The reflux ratio of the plate distillation column is (0.1-10):

1.

24. The separation method according to claim 20, characterized in that, The bottom temperature of the plate distillation column is 80-160℃.

25. The separation method according to claim 1, characterized in that, The separation method includes the following steps: (1) The first mixture containing ethylene carbonate and chloroethylene carbonate is mixed with a substituted halobenzene compound and subjected to a first separation to obtain ethylene carbonate and a second mixture containing chloroethylene carbonate, respectively. The substituted halobenzene compound is an alkyl-substituted halobenzene; the number of alkyl groups in the alkyl-substituted halobenzene is 1-5; the alkyl groups in the alkyl-substituted halobenzene are C1-C6 straight-chain or branched alkyl groups; the alkyl-substituted halobenzene compound is any one or a combination of at least two of alkyl-substituted chlorobenzene, alkyl-substituted bromobenzene, or alkyl-substituted iodobenzene. The first mixture is a chlorination reaction solution of ethylene carbonate; the mass ratio of ethylene carbonate to chloroethylene carbonate in the first mixture is (0.1-10):1; the mass ratio of the substituted halobenzene compound to the first mixture is (0.01-0.5):1; The first separation is a high-gravity distillation; the vacuum degree of the high-gravity distillation is 0.1-10 kPaA, and the rotation speed is 500-2000 rpm; (2) The second mixture from step (1) is subjected to a second separation to obtain chloroethylene carbonate and substituted halobenzene compounds, respectively. The obtained substituted halobenzene compounds are recycled in the first separation. The second separation method is distillation or crystallization.

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