Systems and methods for transesterification and co-production of battery grade methyl ethyl carbonate and diethyl carbonate

Abstract

This invention relates to the chemical industry, specifically to a transesterification reaction system and a method for co-producing battery-grade methyl ethyl carbonate and diethyl carbonate. The system includes: a raw material vaporization unit, an adiabatic reaction unit, and an alcohol-ester separation unit connected in series along the material flow direction; and a purification unit, the inlet of which is connected to the ester-containing stream outlet of the alcohol-ester separation unit via a pipeline. The technical solution of this invention, by employing a gas-solid phase reaction within an adiabatic reactor, improves the reaction rate and reactor production capacity, reduces energy consumption, extends catalyst lifespan, simplifies the process flow, and reduces production costs while ensuring product purity.

Description

Technical Field

[0001] This invention relates to the chemical industry, specifically to a transesterification reaction system and a method for co-producing battery-grade methyl ethyl carbonate and diethyl carbonate. Background Technology

[0002] Currently, the mature electrolyte solvents for lithium / sodium-ion batteries are complexes of organic carbonate compounds. Among them, ethyl methyl carbonate (EMC) has gradually become the main solvent due to its superior overall performance in terms of low-temperature performance, solubility, and safety stability, and its mass content exceeds 50% in some solvent formulations. Diethyl carbonate (DEC) is also a mature electrolyte solvent for lithium / sodium-ion batteries. In addition, EMC and DEC are also widely used as excellent solvents and important organic synthesis intermediates in industrial, pharmaceutical, agrochemical, hydrocarbon refining, paint and coating, and fragrance industries.

[0003] The transesterification of dimethyl carbonate (DMC) and ethanol to prepare EMC and DEC uses inexpensive raw materials and a simple, mild reaction process, making it the mainstream industrial method for synthesizing EMC and DEC. Currently, the reaction processes and catalysts used in industry mainly employ reactive distillation and sodium methoxide or sodium ethoxide catalysts. For example, ethanol and the catalyst are fed from the top of a reactive distillation column, while DMC is fed from the bottom. After multiple reactive distillations and separation and purification steps, the final product is obtained. Keller T et al. controlled the product distribution of the DMC-ethanol reaction by adjusting multiple parameters of the reactive distillation column, achieving an EMC selectivity of 79.2% or a DEC selectivity of 80.2% within the same column (Chem. Eng. J 2012, 180, 309−322). However, the catalyst is prone to deactivation during the reaction, generating sodium carbonate and sodium bicarbonate, causing pipeline blockage. Furthermore, the catalyst consumption is high and non-recyclable, and the consumption of the catalyst generates a large amount of waste residue, significantly increasing production costs.

[0004] Numerous reports have also been published on reactor and reaction process optimization. For example, CN116212759A discloses a co-production equipment and process for battery-grade dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate. DMC and ethanol react in an EMC pre-reactor and an EMC reaction tower to obtain a product mixture, which then passes through a DMC recovery tower, a coarse separation tower, an EMC crude product tank, an EMC light product removal tower, an EMC heavy product removal tower, a DEC crude product tank, and a DEC light product removal tower, and a DEC heavy product removal tower to obtain battery-grade EMC and DEC. Currently reported reaction purification processes are still relatively complex, energy-intensive, and have high production costs.

[0005] Numerous reports have also been published on catalysts. Alkali catalysts are highly efficient catalysts for the synthesis of methyl ethyl carbonate and diethyl carbonate via transesterification reactions, including liquid-phase (homogeneous) and gas-phase (heterogeneous, multiphase) reaction catalysts. Currently, industrial applications utilize sodium methoxide and sodium ethoxide liquid-phase catalysts. Although these catalysts exhibit high activity, they are prone to deactivation during the reaction, generating sodium carbonate and sodium bicarbonate, causing pipeline blockage. Furthermore, the catalyst consumption is high and non-recyclable, while the consumption of catalysts generates a large amount of waste, significantly increasing catalyst costs. Compared to liquid-phase catalysts, the use of gas-phase reaction catalysts avoids the separation of catalyst and product, enabling continuous production with high efficiency and reduced production costs. For existing gas-phase reaction processes, although reported solid alkaline catalysts exhibit high catalytic activity under mild conditions, problems such as catalyst deactivation, complex preparation processes, and equipment corrosion still exist, hindering the industrial application of solid alkaline multiphase catalysts. For example, CN118022713A discloses an acid-base bifunctional catalyst for the synthesis of ethyl methyl carbonate from dimethyl carbonate and ethanol. This catalyst is prepared by supporting a magnesium-based composite metal oxide on a silica support. The magnesium-based composite metal oxide is a combination of magnesium oxide and an oxide selected from aluminum, manganese, lanthanum, and iron. The molar ratio of magnesium to the metal selected from aluminum, manganese, lanthanum, and iron is 1:0.2-1:5, and the loading of the magnesium-based composite metal oxide is 14%-40%. However, the catalyst preparation process is complex, costly, and has low activity, which is not conducive to the industrial scale-up of the catalyst.

[0006] Therefore, although reactive distillation reactors and their homogeneous catalysts have high catalytic activity for DMC and ethanol transesterification and high product yield, they have disadvantages such as complex separation processes and high production costs. On the other hand, heterogeneous catalysts have lower activity and cannot meet the needs of industrial production. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems of complex transesterification processes, high energy consumption, low efficiency, low product yield, and short catalyst lifespan in existing technologies. It provides a transesterification system and a method for co-producing battery-grade methyl ethyl carbonate and diethyl carbonate. This system and method are characterized by simpler processes, lower energy consumption, higher efficiency, higher product yield, and improved catalyst lifespan.

[0008] To achieve the above objectives, a first aspect of the present invention provides a system for transesterification reaction, the system comprising: a raw material vaporization unit, an adiabatic reaction unit, and an alcohol-ester separation unit connected in series along the material flow direction; and a purification unit, wherein the inlet of the purification unit is connected to the ester-containing stream outlet of the alcohol-ester separation unit via a pipeline.

[0009] A second aspect of the present invention provides a method for co-producing battery-grade methyl ethyl carbonate and diethyl carbonate, the method being carried out in the system described in the first aspect, comprising the following steps: (1) Dimethyl carbonate and ethanol are fed into the raw material vaporization unit to obtain steam reaction material; (2) The steam reactants enter the adiabatic reaction unit and, in the presence of a solid alkali catalyst, obtain the reaction liquid; (3) The reaction liquid is passed into the alcohol-ester separation unit to obtain a stream containing methanol and unreacted raw materials and a mixture stream containing methyl ethyl carbonate and diethyl carbonate. (4) The mixture containing methyl ethyl carbonate and diethyl carbonate is fed into the refining unit to obtain battery-grade methyl ethyl carbonate and battery-grade diethyl carbonate.

[0010] Through the above technical solution, the present invention has the following advantages: The technical solution of this invention improves the reaction rate and reactor production capacity by using gas-solid phase reaction in an adiabatic reactor, reduces energy consumption, extends catalyst lifespan, simplifies the process flow, and reduces production costs while ensuring product purity. Attached Figure Description

[0011] Figure 1 This is an ester exchange system according to a preferred embodiment of the present invention.

[0012] Explanation of reference numerals in the attached figures M101 - Static mixer, E101 - Vaporizer, E102 - Superheater, R101 - Adiabatic reactor, T101 - Alcohol-ester separation tower, E103 - Alcohol-ester separation tower bottom reboiler, E104 - Alcohol-ester separation tower top condenser, T102 - EMC tower, E105 - EMC tower bottom reboiler, E106 - EMC tower top condenser, T103 - Azeotropic tower, E107 - Azeotropic tower bottom reboiler, E108 - Azeotropic tower top condenser, E109 - Pervaporator. Detailed Implementation

[0013] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0014] The present invention provides a transesterification reaction system, the system comprising: a raw material vaporization unit, an adiabatic reaction unit, and an alcohol-ester separation unit connected in series along the material flow direction; and a purification unit, wherein the inlet of the purification unit is connected to the ester-containing stream outlet of the alcohol-ester separation unit via a pipeline.

[0015] The technical solution of this invention improves the reaction rate and reactor production capacity by using gas-solid phase reaction in an adiabatic reactor, reduces energy consumption, extends catalyst lifespan, simplifies the process flow, and reduces production costs while ensuring product purity.

[0016] According to a preferred embodiment of the present invention, the refining unit is made of 304EP grade stainless steel. By adopting the aforementioned preferred solution, product purity can be further guaranteed and production costs can be reduced.

[0017] According to a preferred embodiment of the present invention, the pipeline connected to the refining unit is made of 304EP grade stainless steel. By adopting the aforementioned preferred solution, product purity can be further guaranteed and production costs can be reduced.

[0018] According to a preferred embodiment of the present invention, the alcohol-ester separation unit includes a distillation column, wherein a reboiler is provided at the bottom of the distillation column to circulate the bottom material, and a condenser is provided at the top of the column to circulate the top material. By adopting the aforementioned preferred solution, product purity can be further guaranteed, and production energy consumption and costs can be reduced.

[0019] According to a preferred embodiment of the present invention, the refining unit includes a distillation column, wherein a reboiler is provided at the bottom of the distillation column to circulate the bottom material, and a condenser is provided at the top of the column to circulate the top material. By adopting the aforementioned preferred solution, product purity can be further guaranteed, and production energy consumption and costs can be reduced.

[0020] According to a preferred embodiment of the present invention, the alcohol-ester separation unit includes a distillation column, wherein the reboiler at the bottom and the condenser at the top of the distillation column are made of 304EP grade stainless steel. By adopting the aforementioned preferred solution, product purity can be further guaranteed and production costs can be reduced.

[0021] According to a preferred embodiment of the present invention, the system further includes a reaction raw material mixing unit, the material outlet of which is connected to the feed inlet of the raw material vaporization unit via a pipeline. By adopting the aforementioned preferred solution, the reaction efficiency can be further improved.

[0022] According to a preferred embodiment of the present invention, the system further includes an azeotropic separation unit, wherein the raw material inlet of the azeotropic separation unit is connected to the alcohol-containing stream outlet of the alcohol-ester separation unit via a pipeline.

[0023] According to a preferred embodiment of the present invention, the azeotropic separation unit includes a distillation column, wherein a reboiler is provided at the bottom of the distillation column to circulate the bottom material, and a condenser is provided at the top of the column to circulate the top material. By adopting the aforementioned preferred scheme, the separation of azeotropes can be fully realized.

[0024] According to a preferred embodiment of the present invention, the system further includes a dehydration unit, wherein the raw material inlet of the dehydration unit is connected to the ester-containing stream outlet of the azeotropic separation unit via a pipeline.

[0025] According to a preferred embodiment of the present invention, the dehydration unit includes a pervaporator, which comprises a molecular sieve permeation membrane. By adopting the aforementioned preferred solution, moisture can be further removed from the target material, which is beneficial for subsequent recycling.

[0026] According to a preferred embodiment of the present invention, the ester outlet of the dehydration unit is connected to the reaction feed mixing unit and / or the feed vaporization unit via a pipeline. By adopting the aforementioned preferred solution, production costs can be further reduced.

[0027] According to a preferred embodiment of the present invention, a superheater is provided on the pipeline connecting the raw material vaporization unit and the adiabatic reaction unit to ensure that the raw material is fully preheated to the reaction temperature and to effectively avoid side reactions caused by excessively high raw material temperature.

[0028] This invention provides a method for co-producing battery-grade methyl ethyl carbonate and diethyl carbonate, the method being carried out in the aforementioned system and comprising the following steps: (1) Dimethyl carbonate and ethanol are fed into the raw material vaporization unit to obtain steam reaction material; (2) The steam reactants enter the adiabatic reaction unit and, in the presence of a solid alkali catalyst, obtain the reaction liquid; (3) The reaction liquid is passed into the alcohol-ester separation unit to obtain a stream containing methanol and unreacted raw materials and a mixture stream containing methyl ethyl carbonate and diethyl carbonate. (4) The mixture containing methyl ethyl carbonate and diethyl carbonate is fed into the refining unit to obtain battery-grade methyl ethyl carbonate and battery-grade diethyl carbonate.

[0029] The technical solution of this invention improves the reaction efficiency of dimethyl carbonate and ethanol feedstock by using gas-solid phase reaction in an adiabatic reactor, thereby reducing production energy consumption, increasing catalyst lifespan and product purity.

[0030] According to a preferred embodiment of the present invention, the solid base catalyst comprises an activated carbon support and an alkali metal carbonate supported on the activated carbon support. By adopting the aforementioned preferred embodiment, the reaction efficiency can be further improved, production energy consumption can be reduced, and the stability of the catalyst can be guaranteed.

[0031] According to a preferred embodiment of the present invention, the activated carbon support is coconut shell carbon. By adopting the aforementioned preferred solution, the reaction efficiency can be further improved, production energy consumption can be reduced, and the stability of the catalyst can be guaranteed.

[0032] According to a preferred embodiment of the present invention, the alkali metal carbonate is a carbonate of at least one alkali metal selected from sodium, potassium, and cesium. By adopting the aforementioned preferred embodiment, the reaction efficiency can be further improved, production energy consumption reduced, and catalyst stability ensured.

[0033] In this invention, there is no particular limitation on the content of the active component alkali metal carbonate in the catalyst. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the content of alkali metal carbonate is 3-30% based on the total mass of the solid alkali catalyst.

[0034] According to a preferred embodiment of the present invention, in step (3), 50-90% by volume of the stream containing methanol and unreacted raw materials is recycled back to the alcohol ester separation unit. By adopting the aforementioned preferred embodiment, the purity of the product can be further improved.

[0035] According to a preferred embodiment of the present invention, in step (3), a mixture containing ethyl methyl carbonate and diethyl carbonate is recycled back to the alcohol ester separation unit at a volume percentage of 50-90%. By adopting the aforementioned preferred embodiment, the purity of the product can be further improved.

[0036] According to a preferred embodiment of the present invention, in step (4), 50-90% by volume of battery-grade ethyl methyl carbonate is recycled back to the refining unit. By adopting the aforementioned preferred scheme, the purity of the product can be further improved.

[0037] According to a preferred embodiment of the present invention, in step (4), 50-90% by volume of battery-grade diethyl carbonate is recycled back to the refining unit. By adopting the aforementioned preferred solution, the purity of the product can be further improved.

[0038] In order to further improve the reaction effect, according to a preferred embodiment of the present invention, the method further includes: passing dimethyl carbonate raw material and ethanol raw material into the reaction raw material mixing unit, and then passing them into the raw material vaporization unit.

[0039] In order to further reduce production costs, according to a preferred embodiment of the present invention, the method further includes: feeding a stream containing methanol and unreacted raw materials into an azeotropic separation unit to obtain a stream containing methanol and a mixture stream containing dimethyl carbonate and ethanol.

[0040] In this invention, in order to improve the effect of azeotropic separation, according to a preferred embodiment of the invention, 50-90% by volume of the methanol-containing stream is recycled back to the azeotropic separation unit.

[0041] In this invention, in order to improve the effect of azeotropic separation and reduce production costs, according to a preferred embodiment of the invention, 50-90% by volume of the mixture containing dimethyl carbonate and ethanol is recycled back to the azeotropic separation unit, and the remainder is sent to the dehydration unit to remove moisture and then recycled back to the reaction raw material mixing unit and / or the raw material vaporization unit.

[0042] In this invention, the operating conditions of the raw material vaporization unit can be selected from a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the operating conditions of the raw material vaporization unit include: a temperature of 100-130°C and an operating pressure of 100-300 kPa.

[0043] According to a preferred embodiment of the present invention, the operating conditions of the adiabatic reaction unit include: a temperature of 130-150°C, a pressure of 100-300 kPa, and a space velocity of 0.1-10 h⁻¹. -1 By adopting the aforementioned preferred scheme, the reaction efficiency can be further improved, production energy consumption can be reduced, and the stability of the catalyst can be guaranteed.

[0044] According to a preferred embodiment of the present invention, the operating temperature of the adiabatic reaction unit is 20-40°C higher than the operating temperature of the raw material vaporization unit. By adopting the aforementioned preferred solution, the reaction efficiency can be further improved, production energy consumption can be reduced, and the stability of the catalyst can be guaranteed.

[0045] In this invention, the operating conditions of the alcohol-ester separation unit can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the operating conditions of the alcohol-ester separation unit include: a temperature of 90-150°C and a pressure of 100-200 kPa, wherein the temperature of the reboiler is 130-150°C and the temperature of the condenser is 90-100°C.

[0046] In this invention, the operating conditions of the refining unit can be selected from a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the operating conditions of the refining unit include: a temperature of 100-150°C and a pressure of 5-30 kPa, wherein the temperature of the reboiler is 125-150°C and the temperature of the condenser is 100-120°C.

[0047] In this invention, the amount of reactants can be selected from a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the molar ratio of dimethyl carbonate and ethanol introduced into the raw material vaporization unit is 10:1 to 1:10.

[0048] In this invention, the operating conditions of the azeotropic separation unit can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the operating conditions of the azeotropic separation unit include: a temperature of 60-100°C and an operating pressure of 5-30 kPa, wherein the temperature of the reboiler is 60-100°C and the temperature of the condenser is 65-80°C.

[0049] In this invention, the operating conditions of the dehydration unit can be selected from a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the operating conditions of the dehydration unit include: a temperature of 80-100°C and an operating pressure of 5-20 kPa.

[0050] like Figure 1 As shown, the present invention provides a system for co-producing battery-grade methyl ethyl carbonate and diethyl carbonate via transesterification reaction, comprising a static mixer M101, a vaporizer E101, a superheater E102, an adiabatic reactor R101, an alcohol-ester separation tower T101, a reboiler at the bottom of the alcohol-ester separation tower E103, a condenser at the top of the alcohol-ester separation tower E104, an EMC tower T102, a reboiler at the bottom of the EMC tower E105, a condenser at the top of the EMC tower E106, an azeotropic tower T103, a reboiler at the bottom of the azeotropic tower E107, a condenser at the top of the azeotropic tower E108, and a pervaporator E109. The static mixer M101 is connected to the vaporizer E101 via a pipeline. The vaporizer E101 is connected to the adiabatic reactor R101. The bottom of the adiabatic reactor R101 is connected to the alcohol-ester separation tower T101 via a pipeline. The bottom of the alcohol-ester separation tower T101 is used to collect methyl ethyl carbonate and diethyl carbonate materials, and the top of the alcohol-ester separation tower T101 is used to collect methanol, unreacted dimethyl carbonate, and ethanol materials. The alcohol-ester separation tower T101 is configured with... The alcohol-ester separation column includes a reboiler E103 at the bottom and a condenser E104 at the top. The reboiler E103 controls the bottom temperature of the alcohol-ester separation column, and the condenser E104 controls the top temperature. The bottom of the alcohol-ester separation column, T101, is connected to an EMC column, T102, via a pipeline. The bottom of the EMC column, T102, is used to obtain battery-grade diethyl carbonate, and the top of the EMC column, T102, is used to obtain... Battery-grade ethyl methyl carbonate is obtained. The EMC column T102 is equipped with an EMC column bottom reboiler E105 and an EMC column top condenser E106. The EMC column bottom reboiler E105 is used to control the EMC column bottom temperature, and the EMC column top condenser E106 is used to control the EMC column top temperature. The top of the alcohol-ester separation column T101 is connected to the azeotropic column T103 via a pipeline. The bottom of the azeotropic column T103 is used to obtain dimethyl carbonate and ethanol. The top of the azeotropic tower T103 is used to obtain methanol. The azeotropic tower T103 is equipped with an azeotropic tower bottom reboiler E107 and an azeotropic tower top condenser E108. The azeotropic tower bottom reboiler E107 is used to control the temperature of the azeotropic tower bottom, and the azeotropic tower top condenser E108 is used to control the temperature of the azeotropic tower top. The bottom of the azeotropic tower T103 is connected to a pervaporator through a pipeline. The material entering the pervaporator E109 is dehydrated and then recycled back to the static mixer.

[0051] The present invention will be described in detail below through embodiments. In the following embodiments, unless otherwise specified, the raw materials are all commercially available products, and "%" refers to mass.

[0052] Example 1 In such Figure 1 The system shown co-produces battery-grade methyl ethyl carbonate and diethyl carbonate. The operating conditions for each unit are as follows: Catalyst: Coconut shell charcoal supported with 10% by mass of potassium carbonate; Static mixer M101: The molar ratio of ethanol to DMC introduced is 2; Vaporizer E101: Temperature 100℃, operating pressure 200kPa; Adiabatic reactor R101: temperature 140℃, reaction space velocity (WHSV) 5.34 h⁻¹ -1 The pressure is 200 kPa; Alcohol-ester separation column T101: pressure 200 kPa, top circulation rate 52.3%, bottom circulation rate 56.1%; E103 reboiler at the bottom of the alcohol-ester separation column: temperature 130-150℃; E104, the top condenser of the alcohol-ester separation column: temperature is 90-100℃; EMC Tower T102: Pressure is 15 kPa, top circulation rate is 86.6%, bottom circulation rate is 78.7%, and material is 304EP grade stainless steel; EMC column bottom reboiler E105: temperature 130-150℃, material is 304EP grade stainless steel; EMC tower top condenser E106: temperature range 100-120℃, material is 304EP grade stainless steel; Azeotropic tower T103: pressure 15 kPa, top circulation rate 88.6%, bottom circulation rate 80.4%; Azeotropic column bottom reboiler E107: temperature 85-100℃; Azeotropic column top condenser E108: temperature 65-80℃; Pervaporator E109: Equipped with NaA type inorganic molecular sieve permeation membrane, temperature is 90℃, operating pressure is 10kPa.

[0053] Reaction results: All products were analyzed online by GC with an FID detector. The DMC conversion was found to be 53.4%, and the selectivity for EMC and DEC was 68.4% and 31.6%, respectively. Catalyst stability data are shown in the table below:

[0054] Under these operating conditions, the total heating consumption is 2.1 Gcal / ton of product.

[0055] Example 2 Similar to Embodiment 1, except that the operating conditions of each device are as follows: Catalyst: Coconut shell charcoal supported with 20% sodium carbonate by mass; Static mixer M101: The molar ratio of ethanol to DMC introduced is 2; Vaporizer E101: Temperature is 110℃, operating pressure is 100kPa; Adiabatic reactor R101: temperature 130℃, reaction space velocity (WHSV) 5.34 h⁻¹ -1 The pressure is 100 kPa; Alcohol-ester separation tower T101: pressure 150 kPa, top circulation rate 58.9%, bottom circulation rate 63.7%; E103 reboiler at the bottom of the alcohol-ester separation column: temperature 130-150℃; E104, the top condenser of the alcohol-ester separation column: temperature is 90-100℃; EMC Tower T102: Pressure is 10 kPa, top circulation rate is 78.5%, bottom circulation rate is 76.2%, and material is 304EP grade stainless steel; EMC column bottom reboiler E105: temperature 130-150℃, material is 304EP grade stainless steel; EMC tower top condenser E106: temperature range 100-120℃, material is 304EP grade stainless steel; Azeotropic tower T103: pressure 8 kPa, top circulation rate 89.3%, bottom circulation rate 85.2%; Azeotropic column bottom reboiler E107: temperature 85-100℃; Azeotropic column top condenser E108: temperature 65-80℃; Pervaporator E109: Equipped with NaA type inorganic molecular sieve permeation membrane, temperature is 80℃, operating pressure is 50kPa.

[0056] Reaction results: All products were analyzed online by GC with an FID detector. The DMC conversion rate was 48.5%, and the selectivities for EMC and DEC were 77.9% and 22.1%, respectively. The purity of EMC at the top of the EMC column was 99.99%, and the purity of DEC at the bottom of the column was 99.99%.

[0057] Example 3 Similar to Embodiment 1, except that the operating conditions of each device are as follows: Catalyst: 25% rubidium carbonate supported on coconut shell charcoal; Static mixer M101: The molar ratio of ethanol to DMC introduced is 2; Vaporizer E101: Temperature is 130℃, operating pressure is 300kPa; Adiabatic reactor R101: temperature 150℃, reaction space velocity (WHSV) 5.34 h⁻¹ -1 The pressure is 300 kPa; Alcohol-ester separation tower T101: pressure 200 kPa, top circulation rate 54.1%, bottom circulation rate 57.3%; E103 reboiler at the bottom of the alcohol-ester separation column: temperature 130-150℃; E104, the top condenser of the alcohol-ester separation column: temperature is 90-100℃; EMC Tower T102: Pressure is 30 kPa, top circulation rate is 81.3%, bottom circulation rate is 78.6%, and material is 304EP grade stainless steel; EMC column bottom reboiler E105: temperature 130-150℃, material is 304EP grade stainless steel; EMC tower top condenser E106: temperature range 100-120℃, material is 304EP grade stainless steel; Azeotropic tower T103: pressure 30 kPa, top circulation rate 87.2%, bottom circulation rate 83.8%; Azeotropic column bottom reboiler E107: temperature 85-100℃; Azeotropic column top condenser E108: temperature 65-80℃; Pervaporator E109: Equipped with a 3A molecular sieve permeation membrane, operating temperature is 100℃, and operating pressure is 20kPa.

[0058] Reaction results: All products were analyzed online by GC with an FID detector. The single-pass conversion of DMC was 52.2%, and the selectivities of EMC and DEC were 71.7% and 28.3%, respectively. The purity of EMC at the top of the EMC column was 99.99%, and the purity of DEC at the bottom of the column was 99.99%.

[0059] Example 4 Same as Example 1, except that the material is ordinary carbon steel.

[0060] Reaction results: The conversion rate and selectivity were comparable, but the impurity content of the product increased. Taking the DE column as an example, the comparison of metal content in the product is shown in the table below.

[0061]

[0062] Example 5 Same as Example 1, except that: there is no circulation at the top of the EMC tower.

[0063] Reaction results: The composition of the EMC tower top is compared in the table below:

[0064] Example 6 Same as Example 1, except that: the temperature of vaporizer E101 is the same as the operating temperature of adiabatic reactor R101, which is 140°C.

[0065] Reaction results: The conversion rates of DMC were comparable, but the selectivity of EMC and DEC both decreased to 65.6% and 27.3%, respectively, and the product purity decreased significantly, indicating that side reactions occurred.

[0066] Comparative Example 1 Same as Example 1, except that the adiabatic reactor is replaced with an empty tube reactor.

[0067] Reaction results: The reaction efficiency decreased, with a single-pass conversion rate of 31.2% for DMC, and selectivities of 91.4% and 8.6% for EMC and DEC, respectively. Furthermore, the catalyst activity decreased significantly after 24 hours of use, with a 5% reduction in conversion rate compared to the initial value. The total heating required for this process was 3.5 Gcal / ton of product.

[0068] Comparative Example 2 Similar to Example 1, except that instead of using an adiabatic reactor and alcohol-ester separation tower T101, a reactive distillation tower is used so that the reaction and separation are carried out in the same distillation tower.

[0069] Reaction results: The catalyst was rapidly deactivated within 24 hours, and the conversion rate of DMC dropped to almost 0.

[0070] Comparative Example 3 Same as Example 1, except that a vaporizer E101 is not provided.

[0071] Reaction results: The reaction efficiency decreased, and the single-pass conversion rate of DMC was measured to be 10.3%, while the selectivity of EMC and DEC was 95.5% and 4%, respectively.

[0072] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A system for transesterification, characterized in that, The system includes: a raw material vaporization unit, an adiabatic reaction unit, and an alcohol-ester separation unit connected in series along the material flow direction; and a refining unit, wherein the inlet of the refining unit is connected to the ester-containing stream outlet of the alcohol-ester separation unit via a pipeline.

2. The system according to claim 1, characterized in that, The refining unit is made of 304EP grade stainless steel; and / or The pipeline connected to the refining unit is made of 304EP grade stainless steel.

3. The system according to claim 1, characterized in that, The alcohol-ester separation unit includes a distillation column, wherein a reboiler is provided at the bottom of the distillation column to circulate the bottom material, and a condenser is provided at the top of the column to circulate the top material; and / or The refining unit includes a distillation column, which has a reboiler at the bottom for circulating the bottom material and a condenser at the top for circulating the top material.

4. The system according to claim 1, characterized in that, The alcohol-ester separation unit includes a distillation column, and the bottom reboiler and top condenser of the distillation column are made of 304EP grade stainless steel.

5. The system according to claim 1, characterized in that, The system also includes a reaction raw material mixing unit, the material outlet of which is connected to the feed inlet of the raw material vaporization unit via a pipeline.

6. The system according to claim 1, characterized in that, The system further includes an azeotropic separation unit, the raw material inlet of which is connected to the alcohol-containing stream outlet of the alcohol-ester separation unit via a pipeline.

7. The system according to claim 6, characterized in that, The azeotropic separation unit includes a distillation column, which has a reboiler at the bottom for circulating the bottom material and a condenser at the top for circulating the top material.

8. The system according to claim 7, characterized in that, The system further includes a dehydration unit, the raw material inlet of which is connected to the ester-containing stream outlet of the azeotropic separation unit via a pipeline.

9. The system according to claim 8, characterized in that, The dehydration unit includes a pervaporator, which comprises a molecular sieve permeation membrane; and / or The ester outlet of the dehydration unit is connected to the reaction feed mixing unit and / or the feed vaporization unit via a pipeline.

10. The system according to claim 7, characterized in that, A superheater is installed on the pipeline connecting the raw material vaporization unit and the adiabatic reaction unit.

11. A method for co-producing battery-grade methyl ethyl carbonate and diethyl carbonate, characterized in that, The method, performed in the system described in any one of claims 1-10, includes the following steps: (1) Dimethyl carbonate and ethanol are fed into the raw material vaporization unit to obtain steam reaction material; (2) The steam reactants enter the adiabatic reaction unit and, in the presence of a solid alkali catalyst, obtain the reaction liquid; (3) The reaction liquid is passed into the alcohol-ester separation unit to obtain a stream containing methanol and unreacted raw materials and a mixture stream containing methyl ethyl carbonate and diethyl carbonate. (4) The mixture containing methyl ethyl carbonate and diethyl carbonate is fed into the refining unit to obtain battery-grade methyl ethyl carbonate and battery-grade diethyl carbonate.

12. The method according to claim 11, characterized in that, The solid base catalyst comprises an activated carbon support and an alkali metal carbonate supported on the activated carbon support.

13. The method according to claim 12, characterized in that, The activated carbon carrier is coconut shell charcoal; and / or The alkali metal carbonate is a carbonate of at least one alkali metal selected from sodium, potassium, and cesium.

14. The method according to claim 12, characterized in that, The alkali metal carbonate content is 3-30% based on the total mass of the solid base catalyst.

15. The method according to claim 11, characterized in that, In step (3), A stream containing methanol and unreacted feedstock is recycled back 50-90% by volume to the alcohol-ester separation unit; and / or A mixture containing methyl ethyl carbonate and diethyl carbonate is recycled back to the alcohol ester separation unit at a volume percentage of 50-90%.

16. The method according to claim 11, characterized in that, In step (4), Battery-grade ethyl methyl carbonate 50-90% by volume is recycled back to the refining unit; and / or Battery-grade diethyl carbonate 50-90% by volume is recycled back to the refining unit.

17. The method according to claim 11, characterized in that, The method further includes: After the dimethyl carbonate and ethanol feedstocks are introduced into the reaction feedstock mixing unit, they are then introduced into the feedstock vaporization unit; and / or The stream containing methanol and unreacted feedstock is fed into an azeotropic separation unit to obtain a methanol-containing stream and a mixture stream containing dimethyl carbonate and ethanol.

18. The method according to claim 17, characterized in that, The methanol-containing stream is recycled back to the azeotropic separation unit at a rate of 50-90% by volume; and / or The mixture containing dimethyl carbonate and ethanol is recycled back to the azeotropic separation unit at a volume rate of 50-90%, and the remainder is sent to the dehydration unit to remove moisture and then recycled back to the reaction feed mixing unit and / or feed vaporization unit.

19. The method according to claim 11, characterized in that, The operating conditions of the raw material vaporization unit include: a temperature of 100-130℃ and an operating pressure of 100-300 kPa; and / or The operating conditions of the adiabatic reaction unit include: temperature of 130-150℃, pressure of 100-300kPa, and space velocity of 0.1-10h. -1 .

20. The method according to claim 11, characterized in that, The operating temperature of the adiabatic reaction unit is 20-40°C higher than that of the raw material vaporization unit.

21. The method according to claim 11, characterized in that, The operating conditions of the alcohol-ester separation unit include: a temperature of 90-150℃ and a pressure of 100-200kPa, wherein the temperature of the reboiler is 130-150℃ and the temperature of the condenser is 90-100℃.

22. The method according to claim 11, characterized in that, The operating conditions of the refining unit include: a temperature of 100-150℃ and a pressure of 5-30kPa, wherein the temperature of the reboiler is 125-150℃ and the temperature of the condenser is 100-120℃.

23. The method according to claim 11, characterized in that, The molar ratio of dimethyl carbonate and ethanol introduced into the raw material vaporization unit is 10:1 to 1:10.

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