A method for extracting vinylene carbonate from a vinylene carbonate pot residue

Abstract

The application provides a method for extracting vinylene carbonate from vinylene carbonate still residue, which comprises the following steps: dissolving the vinylene carbonate still residue by using an organic solvent, and then performing pressure filtration and post-treatment to obtain the vinylene carbonate. The method for extracting the vinylene carbonate from the vinylene carbonate still residue does not need to use water as an extractant, directly uses the organic solvent to dissolve and then performs filtration, reduces the participation of water, and improves the extraction yield. The operation is simple and convenient, does not need to be treated in a high-temperature environment, can quickly and effectively extract the vinylene carbonate, efficiently recycles the vinylene carbonate still residue, and reduces the cost.

Description

Technical Field

[0001] This invention relates to the field of lithium battery additives, and more specifically to a method for extracting vinylene carbonate from vinylene carbonate residue. Background Technology

[0002] Vinyl carbonate is obtained by adding chloroethylene carbonate to an organic solvent and then adding a catalyst. It is subsequently extracted through distillation. However, during the extraction process, due to the viscosity of the material in the later stages, some residual vinylene carbonate cannot be extracted normally at certain production temperatures and must be discharged as reactor residue. This residue cannot be recycled and is treated as hazardous waste, requiring incineration, resulting in significant waste. The vinylene carbonate reactor residue contains a large amount of tar, approximately 20% vinylene carbonate, and small amounts of EC, DCEC, triethylamine, and other substances. With the rapid development of lithium batteries, the demand for vinylene carbonate is increasing. Further improvements and development are needed to improve the recovery rate of vinylene carbonate from the reactor residue. Summary of the Invention

[0003] To address the shortcomings of existing technologies and solve the aforementioned problems, a method for extracting vinylene carbonate from vinylene carbonate reactor residues is proposed, and the following technical solution is provided:

[0004] A method for extracting vinylene carbonate from vinylene carbonate reactor residue involves dissolving the vinylene carbonate reactor residue with an organic solvent and then performing post-treatment to obtain vinylene carbonate.

[0005] Furthermore, the organic solvent is at least one of chloroalkanes such as dichloromethane and dichloroethane.

[0006] Furthermore, calculated by mass fraction, the ratio of vinylene carbonate residue to organic solvent is 5:1-4.

[0007] Furthermore, the filtration is carried out using a filter press, and the filter cloth used in the filter press has a porosity range of 0.1-50μm.

[0008] Furthermore, the filtration is carried out using a filter press, the filter cloth used in the filter press has a porosity range of 0.1-50μm, and the pressure of the filter press is set to 0.02Mpa-0.05Mpa.

[0009] Furthermore, the post-processing includes vacuum distillation and cooling.

[0010] Furthermore, the conditions for vacuum distillation are: a vacuum degree of -0.09 MPa to 0 MPa, heating from room temperature to 50°C until no material is collected, and the heating rate is 5-10°C every two hours.

[0011] Furthermore, the organic solvent is collected during the vacuum distillation process and used to dissolve the vinylene carbonate residue in the reactor.

[0012] Furthermore, after vacuum distillation, the product is cooled twice. The first cooling temperature is 25-28℃, and the second cooling temperature is 5℃-10℃.

[0013] Furthermore, after the first cooling, the temperature is kept at 25-28℃ for 4-5 hours. After the heat preservation is completed, filtration is performed, followed by a second cooling.

[0014] Furthermore, after the second cooling, the mixture was cooled at 5℃-10℃ for 3-4 hours, and then solid-liquid separation was performed to obtain vinylene carbonate solid.

[0015] Due to the adoption of the above technical solutions, the beneficial technical effects of the present invention are as follows:

[0016] 1. The method of extracting vinylene carbonate from vinylene carbonate residue of the present invention does not require the use of water as an extractant. Instead, it directly uses an organic solvent to dissolve the carbonate and then performs pressure filtration, which reduces the involvement of water and improves the extraction yield.

[0017] 2. This invention achieves the extraction of vinylene carbonate from vinylene carbonate residue by sequentially designing an overall process of organic solvent dissolution, filtration, vacuum distillation and cooling. The sequential coordination of each process extracts vinylene carbonate from the vinylene carbonate residue, and the recovery rate of vinylene carbonate reaches more than 95%.

[0018] 3. This invention is simple and convenient to operate, does not require high-temperature treatment, can quickly and effectively extract vinylene carbonate, and efficiently recovers vinylene carbonate residues from the reactor, thus reducing costs. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Based on the embodiments in this application, other similar embodiments obtained by those skilled in the art without creative effort should all fall within the scope of protection of this application.

[0020] A method for extracting vinylene carbonate from vinylene carbonate residue from a reactor is disclosed. The method involves dissolving the residue in an organic solvent, followed by pressure filtration, and then further processing to obtain vinylene carbonate. This method eliminates the need for water as an extractant, directly using an organic solvent for dissolution and filtration, thus reducing water involvement and increasing the extraction yield. The operation is simple and convenient, requiring no high-temperature treatment, and allows for rapid and effective extraction of vinylene carbonate. It also enables efficient recovery of the residue, reducing costs. The organic solvent dissolves the vinylene carbonate residue; the pressure filtration process effectively removes solid particles and a large amount of tar, leaving primarily the extraction solvent, vinylene carbonate, and ethylene carbonate.

[0021] It is simple and convenient to operate, and can quickly and effectively purify vinylene carbonate products. This reduces the generation of hazardous waste and increases the output of enterprises, which is more in line with the theme of safe and environmentally friendly production.

[0022] This scheme aims to improve the recovery rate and content of vinylene carbonate extracted from vinylene carbonate residue. It explores a new extraction process and various process parameters. The order of the extraction process and the parameter conditions have a significant impact on the recovery rate and content of vinylene carbonate. When the extraction process or parameter conditions are changed, the recovery rate of vinylene carbonate will decrease, and the purity of the obtained vinylene carbonate will also decrease.

[0023] After pressure filtration, the solvent is separated and recovered by vacuum distillation. This solvent can be recycled multiple times. Vacuum distillation yields relatively pure vinylene carbonate, ethylene carbonate, and a small amount of unfiltered tar. The high-content vinylene carbonate is then reused in the production process, achieving a recycling effect.

[0024] Example 1

[0025] 100 parts of vinylene carbonate residue were dissolved in 80 parts of dichloromethane, and then filtered using a filter press with a filter cloth porosity of 5 μm and a filtration pressure of 0.02 MPa. The filtered liquid was then subjected to vacuum distillation. The filtered liquid was placed in a sealed reaction vessel, stirred, and evacuated to a vacuum degree of 0 MPa. The temperature was slowly increased from room temperature to 50°C until no further distillation was observed, at a rate of 5°C every two hours. The temperature of the liquid obtained after vacuum distillation was reduced to 28°C. ℃ The liquid was kept at a constant temperature for 4 hours, and then filtered. The filtered liquid was then cooled a second time to 8°C for 3 hours. After cooling, solid-liquid separation was performed, and the obtained solid was pure vinylene carbonate with a content of 90% and a recovery rate of 80%.

[0026] Example 2

[0027] 100 parts of vinylene carbonate residue were dissolved in 20 parts of dichloroethane, and then filtered using a filter press with a filter cloth porosity of 1 μm and a filtration pressure of 0.03 MPa. The filtered liquid was then subjected to vacuum distillation. The filtered liquid was placed in a sealed reaction vessel, stirred, and evacuated to a vacuum degree of -0.07 MPa. The temperature was slowly increased from room temperature to 50°C until no further distillation was observed, at a rate of 8°C every two hours. The temperature of the liquid obtained after vacuum distillation was lowered to 25°C and held at this temperature for 5 hours. After holding at this temperature, the liquid was filtered. The filtered liquid was then cooled a second time to 5°C and cooled for 4 hours. After cooling, solid-liquid separation was performed, and the solid obtained was pure vinylene carbonate with a content of 80% and a recovery rate of 65%.

[0028] Example 3

[0029] 100 parts of vinylene carbonate residue were dissolved in 40 parts of dichloroethane, and then filtered using a filter press with a filter cloth porosity of 10 μm and a filtration pressure of 0.05 MPa. The filtered liquid was then subjected to vacuum distillation. The filtered liquid was placed in a sealed reaction vessel, stirred, and evacuated to a vacuum degree of -0.09 MPa. The temperature was slowly increased from room temperature to 50°C until no further distillation was observed, at a rate of 10°C every two hours. The temperature of the liquid obtained after vacuum distillation was lowered to 27°C and held at this temperature for 4 hours. After holding at this temperature, the liquid was filtered. The filtered liquid was then cooled a second time to 10°C and cooled for 4 hours. After cooling, solid-liquid separation was performed, and the obtained solid was pure vinylene carbonate with a vinylene carbonate content of 95% and a recovery rate of 90%.

[0030] Comparative Example 1

[0031] 100 parts of vinylene carbonate residue were added to 120 parts of water and heated in a water bath at 80°C for two hours. The lower layer was then collected using a separatory funnel and subjected to vacuum distillation. The filtered liquid was placed in a sealed reaction vessel, stirred, and evacuated to a vacuum degree of -0.09 MPa. The temperature was increased from room temperature to 75°C at a rate of 5°C every two hours. The distillate from the early stage of vacuum distillation was discarded, while the later stage yielded vitamin C. The obtained vitamin C was crystallized at 8°C for 3 hours. After cooling, the solid and liquid were separated, and the solid was vinylene carbonate with a content of 80% and a yield of 40%. Some vinylene carbonate reacted with water, resulting in some waste. The initial product from vacuum distillation was a mixture of water and vinylene carbonate, with water making up the majority and vinylene carbonate the minority, which was unusable.

[0032] Comparative Example 2

[0033] Compared to Example 1, no pressure filtration was performed, but the other steps were the same as in Example 1. The vinylene carbonate content was 60%, and the recovery rate was 40%.

[0034] Comparative Example 3

[0035] The filter cloth of the filter press has a porosity of 70 μm, and the filtration pressure is 0.01 MPa. The vinylene carbonate content is 75%, and the recovery rate is 60%.

[0036] As can be seen from Examples 1-3 and Comparative Examples 1-3, the method for extracting vinylene carbonate from vinylene carbonate residue in this scheme does not use water as an extractant. Instead, it directly uses an organic solvent for dissolution followed by pressure filtration, reducing the involvement of water and further improving the recovery rate. In contrast, adding water for extraction requires heating, making the operation more cumbersome. Furthermore, compared to a separatory funnel, the adjustable porosity of the filter cloth and the pressure of the filter press allow for the thorough filtration of solid particles and a large amount of tar. Specifically, in Comparative Example 1, some vinylene carbonate reacts with water, resulting in some waste. During vacuum distillation, the initial product is a mixture of water and vinylene carbonate, with water making up the majority and vinylene carbonate the minority, making it unusable. In Comparative Example 2, no pressure filtration is performed, resulting in some vinylene carbonate being mixed with the tar, and the extracted vinylene carbonate also contains a small amount of tar, leading to low purity and low yield. Comparative Example 3 uses a filter element, but its high porosity results in a small amount of tar remaining in the vinylene carbonate, reducing purity.

[0037] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for extracting vinylene carbonate from vinylene carbonate reactor residue, characterized in that, The residue of vinylene carbonate was dissolved in an organic solvent and then filtered under pressure. After filtration, post-treatment was carried out to obtain vinylene carbonate. The organic solvent is at least one of dichloromethane and dichloroethane; Based on mass fractions, the ratio of vinylene carbonate residue to organic solvent is 5:1-4. The filtration is carried out using a filter press, and the filter cloth used in the filter press has a porosity range of 0.1-50μm. The pressure of the filter press is set to 0.02Mpa-0.05Mpa. The post-processing includes vacuum distillation and cooling; The conditions for vacuum distillation are: vacuum degree between -0.09 MPa and 0 MPa, temperature rise from room temperature to 50°C until no product is collected, and the heating rate is 5-10°C every two hours. After vacuum distillation, the product is cooled twice. The first cooling temperature is 25-28℃, and the second cooling temperature is 5℃-10℃. After the first cooling, keep the temperature at 25-28℃ for 4-5 hours. After the heat preservation is completed, filter the product. After the filtration is completed, cool the product a second time. After the second cooling, the mixture was cooled at 5℃-10℃ for 3-4 hours. After cooling, solid-liquid separation was performed to obtain vinylene carbonate solid.

2. The method for extracting vinylene carbonate from vinylene carbonate reactor residue according to claim 1, characterized in that, Organic solvents are collected during vacuum distillation and used to dissolve vinylene carbonate residues in the reactor.