Method and system for recovering ethyl acetate in sulbactam acid production

Abstract

The invention provides a method and system for recovering ethyl acetate in sulbactam acid production, and the method comprises the following steps: adjusting the pH value of an ethyl acetate mother solution to 5-7, and adding sodium acetate to obtain an adjusted ethyl acetate mother solution; filtering the adjusted ethyl acetate mother liquor to obtain pretreated ethyl acetate mother liquor; rectifying the pretreated ethyl acetate mother liquor to obtain ethyl acetate at the top of a rectifying tower, and recycling the ethyl acetate; a filter material for filtering treatment comprises 40-50 parts by weight of sodium bentonite, 10-20 parts by weight of polytetrafluoroethylene, 5-8 parts by weight of silicon dioxide, 5-7 parts by weight of activated aluminum oxide, 0.5-1 part by weight of a triazinyl covalent organic framework material and 15-20 parts by weight of water; the triazinyl covalent organic framework material is obtained by carrying out solvothermal reaction on melamine and 1, 4-dicyanobenzene. The system comprises an adjusting tank, a rectifying tower and a collecting tank which are sequentially communicated. The recovery efficiency of the ethyl acetate is improved, and the water content of the ethyl acetate is remarkably reduced.

Description

Technical Field

[0001] This application relates to the field of chemical wastewater treatment technology, and in particular to a method and system for recovering ethyl acetate in the production of sulbactamic acid. Background Technology

[0002] Sulbactamic acid is a β-lactamase inhibitor, often used in combination with β-lactam antibiotics (such as cephalosporins or penicillins). It enhances the antibacterial effect by inhibiting the β-lactamase produced by bacteria, protecting the antibiotic from degradation. It itself has no significant antibacterial activity and must be used in combination with other drugs. Clinically, it is mainly used to treat infections caused by drug-resistant bacteria.

[0003] In the production of sulbactam acid, ethyl acetate is usually used as a solvent for extraction after the reaction is completed. In the continuous production process in the factory, a large amount of ethyl acetate mother liquor is generated. If this ethyl acetate mother liquor is directly treated as wastewater, it will not only lead to waste of resources, but also pollute the surrounding environment.

[0004] Traditional methods of treating these ethyl acetate mother liquors by distillation often suffer from high energy consumption and low processing efficiency, which is detrimental to cost control and environmental protection in industrial production. Furthermore, the recovered ethyl acetate contains a high water content. Therefore, developing an efficient and energy-saving solvent recovery process is of great significance. Summary of the Invention

[0005] This application provides a method and system for recovering ethyl acetate in the production of sulbactamic acid, in order to solve the problems mentioned in the background art.

[0006] On the one hand, this application provides a method for recovering ethyl acetate in the production of sulbactamic acid, the method comprising the following steps: Mother liquor pretreatment: The pH of the ethyl acetate mother liquor is adjusted to 5-7 with alkali, and then sodium acetate is added and stirred to obtain the adjusted ethyl acetate mother liquor; Filtration treatment: The adjusted ethyl acetate mother liquor is filtered to obtain the pretreated ethyl acetate mother liquor; Distillation treatment: The pretreated ethyl acetate mother liquor is fed to a distillation column for distillation, and ethyl acetate is obtained at the top of the distillation column and reused; The filter media used in the filtration process includes 40-50 parts by weight of sodium bentonite, 10-20 parts by weight of polytetrafluoroethylene, 5-8 parts by weight of silica, 5-7 parts by weight of activated alumina, 0.5-1 parts by weight of triazine-based covalent organic framework material, and 15-20 parts by weight of water. Triazine-based covalent organic framework materials are obtained by a solvothermal reaction of melamine and 1,4-dicyanobenzene.

[0007] Optionally, the alkali includes at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate.

[0008] Optionally, the amount of sodium acetate added is 4-7 wt% of the ethyl acetate mother liquor.

[0009] Optionally, during the distillation process, the top temperature of the distillation column is 77-79℃, and the bottom temperature of the distillation column is 80-90℃.

[0010] Optionally, methods for preparing triazine-based covalent organic framework materials include: (1) Preparation of precursor solution: 1,4-Dicyanobenzene and melamine were dissolved in dimethyl sulfoxide in a molar ratio of 1:1, and trifluoroacetic acid was added. The mixture was then sonicated for 10-15 minutes with stirring to obtain a precursor solution. (2) Solvothermal reaction: The precursor solution is transferred to a high-pressure reactor, sealed and placed in an oven, and subjected to a solvothermal reaction at 120-140℃ for 12-36h to obtain triazine covalent organic framework material.

[0011] Optionally, the filter media preparation process includes the following steps: (1) Sodium-based bentonite, polytetrafluoroethylene, silica, activated alumina and triazine-based covalent organic framework material are ball-milled for 4-8 hours according to the weight parts; (2) Add water according to the weight ratio and continue ball milling for 20-30 minutes; (3) Granulate into spherical particles with a diameter of 5-10 mm and dry to a moisture content of 1-5%; (4) Firing at 200-400℃ for 1-2 hours to obtain filter material.

[0012] Optionally, the distillation process may also include: A water-ethyl acetate azeotrope is obtained at the top of the distillation column. A portion of the water-ethyl acetate azeotrope is refluxed, and the other portion is separated to obtain a water layer and an ethyl acetate layer. The ethyl acetate layer is then reused.

[0013] Optionally, during the distillation process, the reflux ratio of the distillation column is 1:2-3.

[0014] Optionally, during the distillation process, distillation waste liquid is obtained in the bottom of the distillation column and treated together with the water layer as wastewater.

[0015] On the other hand, this application also provides a system for recovering ethyl acetate in the production of sulbactam acid. The system is used to perform the above-mentioned method for recovering ethyl acetate in the production of sulbactam acid, including a conditioning tank, a filter, a distillation column and a collection tank connected in sequence. The inlet of the conditioning tank is connected to an alkali storage tank and a sodium acetate storage tank. The outlet of the regulating tank is connected to the inlet of the filter 101, the outlet of the filter 101 is connected to the upper feed inlet of the distillation column through a feed pipe, the top outlet of the distillation column is connected to the collection tank through a liquid outlet pipe, and a condenser is installed on the liquid outlet pipe.

[0016] Optionally, a phase separator is installed between the collection tank and the storage tank. The light phase outlet of the phase separator is connected to the collection tank, and the heavy phase outlet of the phase separator is connected to the wastewater pipeline.

[0017] Optionally, a storage tank is provided between the condenser and the collection tank, and the storage tank is also connected to the reflux port of the distillation column via a reflux pipe.

[0018] The method and system for recovering ethyl acetate in the production of sulbactamic acid provided in this application achieve the recovery of ethyl acetate in the production of sulbactamic acid, and have the following advantages compared with the prior art: (1) This application achieves efficient recovery of ethyl acetate through the above scheme, and also makes the recovered ethyl acetate have an ultra-low water content. By adding alkali to the ethyl acetate mother liquor, the pH value of the ethyl acetate mother liquor is adjusted to neutral or weakly acidic, which greatly reduces the corrosion of the ethyl acetate mother liquor on the equipment and extends the service life of the system equipment. By adding sodium acetate to the adjustment tank, the decomposition of ethyl acetate caused by high temperature is reduced, and the adjusted ethyl acetate mother liquor is obtained. Through filtration, not only can the small amount of solid impurities contained in the mother liquor be intercepted, which is beneficial to avoid the accumulation and blockage of solid impurities in the subsequent distillation process of the mother liquor, making the transportation and distillation process smoother and more efficient, but the filter material can also adsorb the water contained in the mother liquor, remove some of the water in the mother liquor in advance in the filtration process, avoid obtaining more ethyl acetate and water azeotrope at the top of the distillation kettle in the subsequent distillation process, thereby reducing the reflux flow of the distillation column, improving the distillation efficiency, and significantly reducing the water content in the finally recovered ethyl acetate, improving the recovery rate and recovery quality of ethyl acetate, which has a significant promoting effect on the efficient utilization of the subsequent return to the production process. The pretreated ethyl acetate mother liquor obtained from filtration is then fed to a distillation column for distillation. Ethyl acetate is obtained at the top of the distillation column, recovered, and reused for the extraction of sulbactamic acid. This setup not only allows for the recovery and reuse of ethyl acetate, avoiding resource waste, but also prevents environmental pollution caused by the discharge of ethyl acetate.

[0019] (2) The filter material provided in this application can not only intercept the small amount of solid impurities contained in the mother liquor, which is beneficial to avoid the accumulation and blockage of solid impurities in the subsequent distillation process of the mother liquor, making the transportation and distillation process smoother and more efficient, but also can adsorb the water contained in the mother liquor, remove some of the water in the mother liquor in advance in the filtration process, avoid obtaining more ethyl acetate and water azeotrope at the top of the distillation kettle in the subsequent distillation process, thereby reducing the reflux flow of the distillation column, improving the distillation efficiency, and significantly reducing the water content in the final recovered ethyl acetate, improving the recovery rate and recovery quality of ethyl acetate, which has a significant promoting effect on the efficient utilization of the subsequent return to the production process.

[0020] Sodium-based bentonite in the filter media facilitates the adsorption of water from the mother liquor. The triazine-based covalent organic framework material, obtained from melamine and 1,4-dicyanobenzene via a solvothermal reaction, is porous and efficiently adsorbs solid impurities from the mother liquor. Simultaneously, the nitrogen-rich structure in the triazine ring, containing hydrophilic amino groups (-NH2), synergistically interacts with silica to improve the separation of water and ethyl acetate. Furthermore, when the mother liquor flows through the filter media, water in the mother liquor approaches the surface of the hydrophilic triazine-based covalent organic framework material and silica more quickly than ethyl acetate. Therefore, during filtration, the addition of triazine-based covalent organic framework material and silica accelerates the separation of water and ethyl acetate, allowing ethyl acetate to pass through the filter media more rapidly. It also helps the absorbent filter media components retain water, further improving filtration efficiency and reducing the water content in ethyl acetate. Simultaneously, silica enhances the overall mechanical strength and compressive strength of the filter media, thereby improving filtration efficiency.

[0021] (3) This application effectively reduces the energy consumption of solvent recovery and the decomposition of ethyl acetate by adding sodium acetate to the ethyl acetate mother liquor and using a dehydration method combining reflux and stratification during distillation.

[0022] (4) This application ensures the purity and quality of the recovered ethyl acetate through distillation. At the same time, the process method of this application simplifies the steps of ethyl acetate recovery and increases the throughput per unit time, making it suitable for industrial production. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1A schematic diagram of the structure of an ethyl acetate recovery system in the production of sulbactamic acid provided in an embodiment of this application; Figure 2 A schematic diagram of the structure of an ethyl acetate recovery system in the production of sulbactamic acid, provided in another embodiment of this application; Figure 3 This is a schematic diagram of the ethyl acetate recovery system in the production of sulbactamic acid, provided in another embodiment of this application.

[0025] Figure label: 1: Adjustment tank; 101: Filter; 110: Alkali storage tank; 120: Sodium acetate storage tank; 130: Feed pipe; 2: Distillation column; 3: Collection tank; 310: Liquid outlet pipe; 320: Condenser; 4: Storage tank; 410: Reflux pipe; 5: Phase separator. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are also within the scope of protection of this application.

[0027] like Figure 1 As shown, this application provides a method for recovering ethyl acetate in the production of sulbactamic acid, the method comprising the following steps: Mother liquor pretreatment: The pH of the ethyl acetate mother liquor is adjusted to 5-7 with alkali, and then sodium acetate is added and stirred to obtain the adjusted ethyl acetate mother liquor; Filtration treatment: The adjusted ethyl acetate mother liquor is filtered to obtain the pretreated ethyl acetate mother liquor; Distillation treatment: The pretreated ethyl acetate mother liquor is fed to a distillation column for distillation, and ethyl acetate is obtained at the top of the distillation column and reused; The filter media used in the filtration process includes 40-50 parts by weight of sodium bentonite, 10-20 parts by weight of polytetrafluoroethylene, 5-8 parts by weight of silica, 5-7 parts by weight of activated alumina, 0.5-1 parts by weight of triazine-based covalent organic framework material, and 15-20 parts by weight of water. Triazine-based covalent organic framework materials are obtained by a solvothermal reaction of melamine and 1,4-dicyanobenzene.

[0028] On the other hand, this application also provides a system for recovering ethyl acetate in the production of sulbactam acid. The system is used to perform the above-mentioned method for recovering ethyl acetate in the production of sulbactam acid. It includes a regulating tank 1, a filter 101, a distillation column 2 and a collection tank 3 connected in sequence. The inlet of the regulating tank 1 is connected to an alkali storage tank 110 and a sodium acetate storage tank 120. The outlet of the regulating tank 1 is connected to the inlet of the filter 101. The outlet of the filter 101 is connected to the upper feed inlet of the distillation column 2 through the feed pipe 130. The top outlet of the distillation column 2 is connected to the collection tank 3 through the liquid outlet pipe 310. A condenser 320 is installed on the liquid outlet pipe 310.

[0029] Specifically, during the production of sulbactamic acid, ethyl acetate is usually used as a solvent for extraction after the reaction is completed. In the continuous production process in the factory, a large amount of ethyl acetate mother liquor is generated. The ethyl acetate mother liquor contains the following components: ethyl acetate, water, trace amounts of sulbactamic acid, and a small amount of solid impurities.

[0030] First, alkali is added to the ethyl acetate mother liquor in the regulating tank 1 through the alkali storage tank 110 to adjust the pH value of the ethyl acetate mother liquor to neutral or weakly acidic. This can greatly reduce the corrosion of the ethyl acetate mother liquor on equipment and pipelines during subsequent processing, extend the service life of the system equipment, and thus improve the recovery efficiency of ethyl acetate.

[0031] Under heating conditions, ethyl acetate readily decomposes into ethanol and acetic acid, leading to a decrease in ethyl acetate recovery efficiency. After pH adjustment, sodium acetate is added to the adjustment tank 1 via the sodium acetate storage tank 120 and stirred. The addition of sodium acetate reduces the decomposition of ethyl acetate caused by high temperature. Simultaneously, the hydrophilicity of sodium acetate promotes the binding of trace amounts of water with it, reducing the formation of azeotropes between water and ethyl acetate, thereby improving the purity of ethyl acetate.

[0032] After the sodium acetate addition is complete, continue stirring for 20-30 minutes to obtain the adjusted ethyl acetate mother liquor. Then, filter the adjusted ethyl acetate mother liquor through a filter medium to obtain the pretreated ethyl acetate mother liquor. The filter media used in the filtration process includes 40-50 parts by weight of sodium bentonite, 10-20 parts by weight of polytetrafluoroethylene, 5-8 parts by weight of silica, 5-7 parts by weight of activated alumina, 0.5-1 parts by weight of triazine-based covalent organic framework material, and 15-20 parts by weight of water. The filtration process not only intercepts small amounts of solid impurities in the mother liquor, preventing their accumulation and clogging during subsequent distillation, thus making the transport and distillation processes smoother and more efficient, but also adsorbs water from the mother liquor, removing some of it beforehand. This prevents the formation of a large amount of ethyl acetate-water azeotrope at the top of the distillation vessel during subsequent distillation, thereby reducing the reflux flow rate of the distillation column, improving distillation efficiency, and significantly reducing the water content in the final recovered ethyl acetate. This improves the recovery rate and quality of ethyl acetate, significantly promoting its efficient utilization in subsequent production processes.

[0033] The sodium-based bentonite in the filter media expands upon contact with water to form a gel, which can form a dense filter cake under pressure, effectively intercepting fine particles. It also has strong hygroscopicity, which is beneficial for adsorbing water in the mother liquor. Polytetrafluoroethylene can perform high-precision filtration, and its good chemical stability, temperature resistance, and corrosion resistance contribute to the stable properties of the filter media. Activated alumina possesses high strength and numerous micropores, exhibiting a strong affinity for water. Triazine-based covalent organic frameworks (CABs), obtained through a solvothermal reaction of melamine and 1,4-dicyanobenzene, are porous and efficiently adsorb solid impurities from the mother liquor. Simultaneously, the nitrogen-rich structure of the triazine ring, containing hydrophilic amino groups (-NH2), synergistically enhances the separation of water and ethyl acetate. The silica surface, rich in silanol groups, exhibits good hydrophilicity. When the mother liquor flows through the filter media, water in the mother liquor approaches the hydrophilic triazine-based CABs and silica surfaces more quickly than ethyl acetate. Therefore, the addition of triazine-based CABs and silica to the filter media accelerates the separation of water and ethyl acetate, allowing ethyl acetate to pass through the filter media rapidly. It also helps the absorbent filter media components retain water, further improving filtration efficiency and reducing the water content in ethyl acetate. Furthermore, silica enhances the overall mechanical strength and compressive strength of the filter media, thereby improving filtration efficiency.

[0034] Furthermore, triazine-based covalent organic framework materials possess a nitrogen-rich structure, wherein below 200°C, the amino group is adsorbed onto the alumina surface via hydrogen bonding or van der Waals forces, while at 200-400°C, the nitrogen atom of the amino group binds to the Lewis acid sites (Al) on the alumina surface. 3+ Coordination occurs, forming surface aluminum amino species; simultaneously, at temperatures above 300℃, the cyano groups in the triazine-based covalent organic framework material can oxidize Lewis acid sites (Al) on the aluminum surface. 3+ Chemical bonding; and the silica surface is rich in silanol groups. During the filter material firing process, the amino groups react with the silanol groups, which can improve the mechanical strength of the filter material with alumina and silica, thereby maintaining the density and uniformity of the filter material during the filtration process. The triazine covalent organic framework material accelerates the rapid separation of water and ethyl acetate through hydrophilicity and improves the mechanical strength of the filter material, ultimately improving the filtration efficiency of the mother liquor and reducing the water content, thereby reducing the water content and quality of the recovered ethyl acetate.

[0035] The pretreated ethyl acetate mother liquor is fed into distillation column 2 through feed pipe 130. The column bottom is heated, and the ethyl acetate and a small amount of water in the pretreated ethyl acetate mother liquor evaporate. The resulting gaseous ethyl acetate and a small amount of water vapor move upwards. The liquid phase of the pretreated ethyl acetate mother liquor is sprayed from the upper middle part of distillation column 2 and moves downwards. The gaseous ethyl acetate and a small amount of water vapor come into countercurrent contact with the liquid phase ethyl acetate mother liquor, undergoing mass and heat exchange. At the top of distillation column 2, gaseous ethyl acetate is obtained and fed to condenser 320 through outlet pipe 310 for condensation. The resulting liquid ethyl acetate is then sent to collection tank 3 for storage and reuse in the extraction of sulbactamic acid. This setup not only allows for the recovery and reuse of ethyl acetate, avoiding resource waste, but also prevents environmental pollution caused by the discharge of ethyl acetate.

[0036] This application achieves efficient recovery of ethyl acetate through the aforementioned scheme, resulting in ethyl acetate with an ultra-low water content. By adding alkali to the ethyl acetate mother liquor to adjust its pH to neutral or weakly acidic, the corrosion of the ethyl acetate mother liquor on equipment is significantly reduced, extending the service life of the system equipment. Adding sodium acetate to the conditioning tank reduces the decomposition of ethyl acetate caused by high temperatures, yielding a conditioned ethyl acetate mother liquor. Filtration not only removes small amounts of solid impurities from the mother liquor, preventing their accumulation and clogging during subsequent distillation, thus making the transport and distillation processes smoother and more efficient, but also allows the filter media to adsorb water from the mother liquor, removing some water in advance during the filtration process. This prevents the formation of a large amount of ethyl acetate-water azeotrope at the top of the distillation vessel during subsequent distillation, thereby reducing the reflux flow rate of the distillation column, improving distillation efficiency, and significantly reducing the water content in the final recovered ethyl acetate. This improves the recovery rate and quality of ethyl acetate, significantly promoting its efficient utilization in subsequent production processes. The pretreated ethyl acetate mother liquor obtained from filtration is then fed to a distillation column for distillation. Ethyl acetate is obtained at the top of the distillation column, recovered, and reused for the extraction of sulbactamic acid. This setup not only allows for the recovery and reuse of ethyl acetate, avoiding resource waste, but also prevents environmental pollution caused by the discharge of ethyl acetate.

[0037] Optionally, the alkali includes at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate.

[0038] Optionally, the amount of sodium acetate added is 4-7 wt% of the ethyl acetate mother liquor.

[0039] Specifically, sodium acetate, as a weak base salt, can neutralize free acetic acid, maintaining the system's pH at 5-7 (weakly acidic to neutral), thus disrupting the acidic catalytic environment. Simultaneously, it buffers the reaction (CH3COOH / CH3COO). - (Balance) Stabilize pH and prevent hydrolysis caused by localized over-acidity.

[0040] The amount of sodium acetate added should be kept appropriate. Excessive addition does not further promote the decomposition of ethyl acetate, resulting in waste of sodium acetate.

[0041] Optionally, during the distillation process, the top temperature of the column is 77-79℃ and the bottom temperature is 80-90℃.

[0042] Specifically, this application employs atmospheric distillation and controls the temperature at the top and bottom of the column, with the temperature during the process kept below 100°C. This effectively reduces energy consumption and recovery costs in the ethyl acetate recovery process, resulting in significant economic benefits for the enterprise.

[0043] Optionally, methods for preparing triazine-based covalent organic framework materials include: (1) Preparation of precursor solution: 1,4-Dicyanobenzene and melamine were dissolved in dimethyl sulfoxide in a molar ratio of 1:1, and trifluoroacetic acid was added. The mixture was then sonicated for 10-15 minutes with stirring to obtain a precursor solution. (2) Solvothermal reaction: The precursor solution is transferred to a high-pressure reactor, sealed and placed in an oven, and subjected to a solvothermal reaction at 120-140℃ for 12-36h to obtain triazine covalent organic framework material.

[0044] Specifically, a triazine-based covalent organic framework material skeleton is obtained by solvothermal reaction of 1,4-dicyanobenzene and melamine, where the cyano group (-C≡N) of 1,4-dicyanobenzene condenses with the amino group (-NH2) of melamine to form a six-membered heterocyclic structure.

[0045] Furthermore, in the precursor solution, the mass-to-volume ratio of the sum of the masses of 1,4-dicyanobenzene and melamine to dimethyl sulfoxide is 0.5-3 g / 60 mL, and the mass-to-volume ratio of the sum of the masses of 1,4-dicyanobenzene and melamine to trifluoroacetic acid is 0.025-0.16 g / 60 mL.

[0046] Furthermore, after the solvothermal reaction is completed, the mixture is cooled to room temperature, and the reactants are washed repeatedly with deionized water and anhydrous ethanol, and then dried in a vacuum drying oven at 70-80℃ for 8-12 hours to obtain triazine-based covalent organic framework materials.

[0047] Optionally, the filter media preparation process includes the following steps: (1) Sodium bentonite, polytetrafluoroethylene, silica, activated alumina and triazine covalent organic framework material are ball-milled for 4-8 hours according to the weight parts to make the particle size of each component in the filter material uniform, which is beneficial to improving the uniformity of the filter material. (2) Add water according to the weight ratio and continue ball milling for 20-30 minutes; (3) Granulate into spherical particles with a diameter of 5-10 mm and dry to a moisture content of 1-5%; (4) Firing at 200-400℃ for 1-2 hours to obtain filter material.

[0048] like Figure 2 , Figure 3 As shown, optionally, the distillation process also includes: A water-ethyl acetate azeotrope is obtained at the top of the distillation column. A portion of the water-ethyl acetate azeotrope is refluxed, and the other portion is separated to obtain a water layer and an ethyl acetate layer. The ethyl acetate layer is then reused.

[0049] Optionally, a storage tank 4 is provided between the condenser 320 and the collection tank 3, and the storage tank 4 is also connected to the reflux port of the distillation column 2 through a reflux pipe 410.

[0050] Specifically, an azeotrope of vaporized water and ethyl acetate is obtained at the top of distillation column 2. This azeotrope is then condensed in condenser 320 to obtain a liquid azeotrope of liquid water and ethyl acetate, which is temporarily stored in storage tank 4. A portion of the liquid azeotrope in storage tank 4 is refluxed through reflux pipe 410, while the remainder is sent to collection tank 3. Through reflux, the reflux liquid comes into countercurrent contact with rising water and ethyl acetate vapor within the column. Through multiple partial vaporization and condensation processes, ethyl acetate is repeatedly separated from impurities, thereby improving the recovery rate of ethyl acetate.

[0051] Optionally, during the distillation process, the reflux ratio of the distillation column is 1:2-3.

[0052] Specifically, the reflux liquid comes into countercurrent contact with rising water and ethyl acetate vapor inside the column. Through multiple partial vaporization and condensation, ethyl acetate is repeatedly separated from impurities such as ethanol and water. Controlling the reflux ratio increases the number of gas-liquid contacts, improves the theoretical plate equivalent number, and thus enhances the separation degree. However, an excessively high reflux ratio may cause excessive ethyl acetate to be carried back to the bottom of the column, which would reduce the yield.

[0053] Optionally, during the distillation process, distillation waste liquid is obtained in the bottom of the distillation column and treated together with the water layer as wastewater.

[0054] Optionally, a phase separator 5 is installed between the collection tank 3 and the storage tank 4. The light phase outlet of the phase separator 5 is connected to the collection tank 3, and the heavy phase outlet of the phase separator 5 is connected to the wastewater pipeline.

[0055] Specifically, a portion of the liquid water and ethyl acetate azeotrope in storage tank 4 is refluxed through reflux pipe 410, while the remaining portion is sent to phase separator 5 for stratification, resulting in a water layer and an ethyl acetate layer. The ethyl acetate layer is then temporarily stored in collection tank 3 for reuse. This combination of reflux and stratification in the distillation process effectively reduces the energy consumption for solvent recovery, decreases the decomposition of ethyl acetate, and improves the recovery rate of ethyl acetate.

[0056] The technical solution of this application will be illustrated in detail below with specific embodiments.

[0057] Example 1 Methods for preparing triazine-based covalent organic framework materials include: (1) Preparation of precursor solution: 1,4-Dicyanobenzene and melamine were dissolved in dimethyl sulfoxide in a molar ratio of 1:1, and trifluoroacetic acid was added. The mixture was then sonicated for 10 min under stirring to obtain a precursor solution. (2) Solvothermal reaction: The precursor solution was transferred to a high-pressure reactor, sealed and placed in an oven, and subjected to a solvothermal reaction at 120°C for 36 h to obtain a triazine covalent organic framework material. Example 2

[0058] Methods for preparing triazine-based covalent organic framework materials include: (1) Preparation of precursor solution: 1,4-Dicyanobenzene and melamine were dissolved in dimethyl sulfoxide in a molar ratio of 1:1, and trifluoroacetic acid was added. The mixture was then sonicated for 15 min under stirring to obtain a precursor solution. (2) Solvothermal reaction: The precursor solution was transferred to a high-pressure reactor, sealed and placed in an oven, and subjected to a solvothermal reaction at 130°C for 24 h to obtain a triazine covalent organic framework material. Example 3

[0059] Methods for preparing triazine-based covalent organic framework materials include: (1) Preparation of precursor solution: 1,4-Dicyanobenzene and melamine were dissolved in dimethyl sulfoxide in a molar ratio of 1:1, and trifluoroacetic acid was added. The mixture was then sonicated for 15 min under stirring to obtain a precursor solution. (2) Solvothermal reaction: The precursor solution was transferred to a high-pressure reactor, sealed and placed in an oven, and subjected to a solvothermal reaction at 140°C for 12 h to obtain a triazine covalent organic framework material. Example 4

[0060] The preparation process of filter media includes the following steps: Triazine-based covalent organic framework materials were obtained using the methods provided in Examples 1-3. Taking the triazine-based covalent organic framework material provided in Example 1 as an example, filter media were prepared. (1) Sodium bentonite, polytetrafluoroethylene, silica, activated alumina and triazine covalent organic framework material are ball-milled for 4 hours according to the weight parts to make the particle size of each component in the filter material uniform, which is beneficial to improving the uniformity of the filter material. (2) Add water according to the weight ratio and continue ball milling for 20 minutes; (3) Granulate into spherical particles with a diameter of 5 mm and dry to a moisture content of 2%; (4) The filter material is obtained by firing at 300℃ for 1 hour. Example 5

[0061] The preparation process of filter media includes the following steps: The difference from Example 4 is that: Taking the triazine-based covalent organic framework material provided in Example 2 as an example, the filter media was prepared. Example 6

[0062] The preparation process of filter media includes the following steps: Taking the triazine-based covalent organic framework material provided in Example 3 as an example, filter media were prepared. Example 7

[0063] The preparation process of filter media includes the following steps: The difference from Example 5 is that: (1) Sodium bentonite, polytetrafluoroethylene, silica, activated alumina and triazine covalent organic framework material are ball-milled for 6 hours according to the weight parts to make the particle size of each component in the filter material uniform, which is beneficial to improving the uniformity of the filter material. (2) Add water according to the weight ratio and continue ball milling for 30 minutes; (3) Granulate into spherical particles with a diameter of 8 mm and dry to a moisture content of 1%; (4) The filter material is obtained by firing at 200℃ for 1 hour. Example 8

[0064] The preparation process of filter media includes the following steps: The difference from Example 5 is that: (1) Sodium bentonite, polytetrafluoroethylene, silica, activated alumina and triazine covalent organic framework material are ball-milled for 8 hours according to the weight parts to make the particle size of each component in the filter material uniform, which is beneficial to improving the uniformity of the filter material. (2) Add water according to the weight ratio and continue ball milling for 25 minutes; (3) Granulate into spherical particles with a diameter of 10 mm and dry to a moisture content of 5%; (4) The filter material is obtained by firing at 400℃ for 1 hour.

[0065] Comparative Example 1 The preparation process of filter media includes the following steps: The difference from Example 5 is that: (4) The filter material is obtained by firing at 195℃ for 1 hour.

[0066] Comparative Example 2 The preparation process of filter media includes the following steps: The difference from Example 5 is that: (4) The filter material is obtained by firing at 205℃ for 1 hour.

[0067] The mechanical strength of the filter media obtained in Examples 4-8, Comparative Example 1, and Comparative Example 2 was tested, including compressive strength and breakage rate. At least three parallel experiments were set up for each experiment, and the average value was taken. The results are shown in Table 1.

[0068] The compressive strength test shall be conducted in accordance with CJ / T 299-2008 "Artificial Ceramsite Filter Media for Water Treatment"; The breakage rate test was conducted in accordance with GB / T 1964-2023, "Test Method for Room Temperature Compressive Strength of Porous Ceramics".

[0069] Table 1

[0070] As shown in Table 1, the mechanical strength of the filter media obtained in Examples 4-8 of this application is significantly improved compared to Comparative Examples 1 and 2. Comparing Examples 4-6 demonstrates that the addition of the triazine-based covalent organic framework material obtained in Example 2 has an excellent effect on improving the mechanical strength of the filter media, and the synthesis conditions of the triazine-based covalent organic framework material provided in Example 2 are superior. Furthermore, comparing Examples 4-6 with Examples 7-8 and Comparative Examples 1-2 shows that the firing temperature has a significant impact on the mechanical strength of the filter media during firing. A firing temperature of 200-400℃ is preferred, and further, 300℃ is optimal.

[0071] The filter media provided in this application has good compressive strength and breakage rate, indicating that the filter media not only has good hardness during use, but is also not easily broken by the continuous impact of the mother liquor. As a result, it can have good stability during the filtration process, improve filtration efficiency while keeping the filter media stable, making the filtration process stable and efficient.

[0072] Example 9 A method and system for recovering ethyl acetate in the production of sulbactamic acid, specifically including the following steps: (1) Mother liquor pretreatment: First, add alkali to the ethyl acetate mother liquor in the adjustment tank 1 through the alkali storage tank 110 to adjust the pH value of the ethyl acetate mother liquor to 5; The amount of sodium acetate added is 4 wt% of the ethyl acetate mother liquor; Sodium acetate was added to conditioning tank 1 through sodium acetate storage tank 120, and stirring was continued for 20 minutes to obtain pretreated ethyl acetate mother liquor, which was then conditioned. (2) The adjusted ethyl acetate mother liquor is fed to filter 101 for filtration to obtain pretreated ethyl acetate mother liquor, wherein the filter material used for filtration is obtained from Example 4.

[0073] (3) Distillation treatment: The pretreated ethyl acetate mother liquor is fed into the distillation column 2 through the feed pipe 130. The column bottom is heated, and the ethyl acetate and a small amount of water in the pretreated ethyl acetate mother liquor are evaporated by heating. The resulting gaseous ethyl acetate and a small amount of water vapor move from bottom to top. The liquid phase of the pretreated ethyl acetate mother liquor is sprayed from the middle and upper part of the distillation column 2 and moves from top to bottom. The gaseous ethyl acetate and a small amount of water vapor come into countercurrent contact with the liquid phase of the ethyl acetate mother liquor and exchange mass and heat. The gaseous ethyl acetate is obtained at the top of the distillation column 2 and is fed to the condenser 320 through the liquid outlet pipe 310 for condensation. The resulting liquid ethyl acetate is fed to the collection tank 3 for storage and is recovered for reuse in the extraction of sulbactam acid.

[0074] During the distillation process, the temperature at the top of the column is 77℃ and the temperature at the bottom of the column is 80℃.

[0075] Example 10 (1) Mother liquor pretreatment: First, add alkali to the ethyl acetate mother liquor in the adjustment tank 1 through the alkali storage tank 110 to adjust the pH value of the ethyl acetate mother liquor to 6; The amount of sodium acetate added was 6 wt% of the ethyl acetate mother liquor; Sodium acetate was added to the regulating tank 1 through the sodium acetate storage tank 120, and stirring was continued for 25 minutes to obtain the pretreated ethyl acetate mother liquor. (2) The adjusted ethyl acetate mother liquor is fed to filter 101 for filtration to obtain pretreated ethyl acetate mother liquor, wherein the filter material used for filtration is obtained from Example 5.

[0076] (3) Distillation treatment: The pretreated ethyl acetate mother liquor is fed into the distillation column 2 through the feed pipe 130. The column bottom is heated, and the ethyl acetate and a small amount of water in the pretreated ethyl acetate mother liquor are evaporated by heating. The resulting gaseous ethyl acetate and a small amount of water vapor move from bottom to top. The liquid phase of the pretreated ethyl acetate mother liquor is sprayed from the middle and upper part of the distillation column 2 and moves from top to bottom. The gaseous ethyl acetate and a small amount of water vapor come into countercurrent contact with the liquid phase ethyl acetate mother liquor and exchange mass and heat. A gaseous water and ethyl acetate azeotrope is obtained at the top of the distillation column 2. The gaseous water and ethyl acetate azeotrope is condensed through the condenser 320 to obtain the liquid phase water and ethyl acetate azeotrope, which is then temporarily stored in the storage tank 4. A portion of the liquid phase water and ethyl acetate azeotrope in the storage tank 4 is refluxed through the reflux pipe 410, and the remaining portion is sent to the collection tank 3 for recovery and reuse for the extraction of sulbactam acid.

[0077] During the distillation process, the top temperature of the column is 78℃, the bottom temperature is 85℃, and the reflux ratio of the distillation column is 1:2.

[0078] Example 11 (1) Mother liquor pretreatment: First, add alkali to the ethyl acetate mother liquor in the adjustment tank 1 through the alkali storage tank 110 to adjust the pH value of the ethyl acetate mother liquor to 7; The amount of sodium acetate added is 4-7 wt% of the ethyl acetate mother liquor; Sodium acetate was added to the regulating tank 1 through the sodium acetate storage tank 120, and stirring was continued for 30 minutes to obtain the pretreated ethyl acetate mother liquor. (2) The adjusted ethyl acetate mother liquor is fed to filter 101 for filtration to obtain pretreated ethyl acetate mother liquor, wherein the filter material used for filtration is obtained from Example 6.

[0079] (3) Distillation treatment: The pretreated ethyl acetate mother liquor is fed into the distillation column 2 through the feed pipe 130. The column bottom is heated, and the ethyl acetate and a small amount of water in the pretreated ethyl acetate mother liquor are evaporated by heating. The resulting gaseous ethyl acetate and a small amount of water vapor move from bottom to top. The liquid phase of the pretreated ethyl acetate mother liquor is sprayed from the middle and upper part of the distillation column 2 and moves from top to bottom. The gaseous ethyl acetate and a small amount of water vapor come into countercurrent contact with the liquid phase ethyl acetate mother liquor and exchange mass and heat. A gaseous water and ethyl acetate azeotrope is obtained at the top of the distillation column 2. The gaseous water and ethyl acetate azeotrope is condensed through the condenser 320 to obtain the liquid phase water and ethyl acetate azeotrope, which is then temporarily stored in the storage tank 4. A portion of the liquid phase water and ethyl acetate azeotrope in the storage tank 4 is refluxed through the reflux pipe 410, and the remaining portion is sent to the collection tank 3 for recovery and reuse for the extraction of sulbactam acid.

[0080] During the distillation process, the top temperature of the column is 79℃, the bottom temperature is 90℃, and the reflux ratio of the distillation column is 1:3.

[0081] Example 12 (1) Mother liquor pretreatment: First, add alkali to the ethyl acetate mother liquor in the adjustment tank 1 through the alkali storage tank 110 to adjust the pH value of the ethyl acetate mother liquor to 7; The amount of sodium acetate added was 7 wt% of the ethyl acetate mother liquor; Sodium acetate was added to the regulating tank 1 through the sodium acetate storage tank 120, and stirring was continued for 30 minutes to obtain the pretreated ethyl acetate mother liquor. (2) The adjusted ethyl acetate mother liquor is fed to filter 101 for filtration to obtain pretreated ethyl acetate mother liquor, wherein the filter material used for filtration is obtained from Example 7.

[0082] (3) Distillation treatment: The pretreated ethyl acetate mother liquor is fed into the distillation column 2 through the feed pipe 130. The column bottom is heated, and the ethyl acetate and a small amount of water in the pretreated ethyl acetate mother liquor are evaporated by heating. The resulting gas phase ethyl acetate and a small amount of water vapor move from bottom to top. The liquid phase pretreated ethyl acetate mother liquor is sprayed from the middle and upper part of the distillation column 2 and moves from top to bottom. The gas phase ethyl acetate and a small amount of water vapor come into countercurrent contact with the liquid phase ethyl acetate mother liquor and exchange mass and heat. A gas phase water and ethyl acetate azeotrope is obtained at the top of the distillation column 2. After the vapor phase water and ethyl acetate azeotrope are condensed in condenser 320, liquid phase water and ethyl acetate azeotrope are obtained and temporarily stored in storage tank 4. A portion of the liquid phase water and ethyl acetate azeotrope in storage tank 4 is refluxed through reflux pipe 410, and the remaining portion is sent to phase separator 5 for stratification to obtain water layer and ethyl acetate layer. The ethyl acetate layer is temporarily stored in collection tank 3 and recycled for the extraction of sulbactam acid. Distillation waste liquid is obtained in the bottom of the distillation column and is treated together with the water layer as wastewater.

[0083] During the distillation process, the top temperature of the column is 79℃, the bottom temperature is 90℃, and the reflux ratio of the distillation column is 1:3.

[0084] Example 13 The difference from Example 12 is that: The filter media used in the filtration process was obtained from Example 8.

[0085] Comparative Example 3 The difference from Example 12 is that: The filter media used in the filtration process was obtained from Comparative Example 1.

[0086] Comparative Example 4 The difference from Example 12 is that: The filter media used in the filtration process was obtained from Comparative Example 2.

[0087] The recovery rate, decomposition rate and water content of ethyl acetate obtained from Examples 9-13 and Comparative Examples 3-4 were tested. At least three parallel experiments were set up for each experiment, and the average value was taken. The results are shown in Table 2.

[0088] Table 2

[0089] As shown in Table 2, the ethyl acetate recovery method and system provided in this application improve both the recovery rate and the quality of the final ethyl acetate. Based on the results in Table 1, Example 10, using the filter media provided in Example 5, exhibits a lower ethyl acetate recovery rate and lower water content, indicating that the filter media provided in Example 5 performs better. This is because the filter media provided in this application not only retains small amounts of solid impurities in the mother liquor, which helps prevent the accumulation and blockage of solid impurities during subsequent distillation, making the conveying and distillation process smoother and more efficient, but also adsorbs water from the mother liquor, removing some of the water in the mother liquor during the filtration process. This avoids obtaining a large amount of ethyl acetate-water azeotrope at the top of the distillation vessel during subsequent distillation, thereby reducing the reflux flow rate of the distillation column, improving distillation efficiency, and significantly reducing the water content in the final recovered ethyl acetate. This improves the recovery rate and quality of ethyl acetate and significantly promotes its efficient utilization in subsequent production processes.

[0090] Sodium-based bentonite in the filter media facilitates the adsorption of water from the mother liquor. The triazine-based covalent organic framework material, obtained from melamine and 1,4-dicyanobenzene via a solvothermal reaction, is porous and efficiently adsorbs solid impurities from the mother liquor. Simultaneously, the nitrogen-rich structure in the triazine ring, containing hydrophilic amino groups (-NH2), synergistically interacts with silica to improve the separation of water and ethyl acetate. Furthermore, when the mother liquor flows through the filter media, water in the mother liquor approaches the surface of the hydrophilic triazine-based covalent organic framework material and silica more quickly than ethyl acetate. Therefore, during filtration, the addition of triazine-based covalent organic framework material and silica accelerates the separation of water and ethyl acetate, allowing ethyl acetate to pass through the filter media more rapidly. It also helps the absorbent filter media components retain water, further improving filtration efficiency and reducing the water content in ethyl acetate. Simultaneously, silica enhances the overall mechanical strength and compressive strength of the filter media, thereby improving filtration efficiency.

[0091] The method and system for recovering ethyl acetate in the production of sulbactamic acid provided in this application effectively reduce the energy consumption of solvent recovery by adding sodium acetate to the ethyl acetate mother liquor, controlling the reflux ratio during distillation, and using a dehydration method combined with stratification. This results in an ethyl acetate recovery rate of greater than or equal to 98%, while achieving a very small amount of ethyl acetate decomposition, with a decomposition rate as low as 2%.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for recovering ethyl acetate in the production of sulbactamic acid, characterized in that, Includes the following steps: Mother liquor pretreatment: The pH value of the ethyl acetate mother liquor is adjusted to 5-7 with alkali, and then sodium acetate is added and stirred to obtain the adjusted ethyl acetate mother liquor; Filtration treatment: The adjusted ethyl acetate mother liquor is filtered to obtain the pretreated ethyl acetate mother liquor; Distillation treatment: The pretreated ethyl acetate mother liquor is fed to a distillation column for distillation, and ethyl acetate is obtained at the top of the distillation column and reused; The filter media used in the filtration process includes 40-50 parts by weight of sodium bentonite, 10-20 parts by weight of polytetrafluoroethylene, 5-8 parts by weight of silica, 5-7 parts by weight of activated alumina, 0.5-1 parts by weight of triazine-based covalent organic framework material, and 15-20 parts by weight of water. The triazine-based covalent organic framework material is obtained by a solvothermal reaction of melamine and 1,4-dicyanobenzene.

2. The method for recovering ethyl acetate in the production of sulbactamic acid according to claim 1, characterized in that, The alkali includes at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate.

3. The method for recovering ethyl acetate in the production of sulbactamic acid according to claim 1, characterized in that, The amount of sodium acetate added is 4-7 wt% of the ethyl acetate mother liquor.

4. The method for recovering ethyl acetate in the production of sulbactamic acid according to claim 1, characterized in that, During the distillation process, the temperature at the top of the column is 77-79℃, and the temperature at the bottom of the column is 80-90℃.

5. The method for recovering ethyl acetate in the production of sulbactamic acid according to claim 1, characterized in that, The preparation method of the triazine-based covalent organic framework material includes: (1) Preparation of precursor solution: 1,4-Dicyanobenzene and melamine were dissolved in dimethyl sulfoxide in a molar ratio of 1:1, and trifluoroacetic acid was added. The mixture was then sonicated for 10-15 minutes with stirring to obtain a precursor solution. (2) Solvothermal reaction: The precursor solution is transferred to a high-pressure reactor, sealed and placed in an oven, and subjected to a solvothermal reaction at 120-140℃ for 12-36h to obtain the triazine covalent organic framework material.

6. The method for recovering ethyl acetate in the production of sulbactamic acid according to claim 1, characterized in that, The preparation process of the filter media includes the following steps: (1) The sodium-based bentonite, the polytetrafluoroethylene, the silica, the activated alumina and the triazine-based covalent organic framework material are ball-milled for 4-8 hours according to the weight parts; (2) Add the water according to the weight ratio and continue ball milling for 20-30 minutes; (3) Granulate into spherical particles with a diameter of 5-10 mm and dry to a moisture content of 1-5%; (4) The filter material is obtained by firing at 200-400℃ for 1-2 hours.

7. The method for recovering ethyl acetate in the production of sulbactamic acid according to claim 1, characterized in that, The distillation process further includes: A water-ethyl acetate azeotrope is obtained at the top of the distillation column. A portion of the water-ethyl acetate azeotrope is refluxed, and the other portion is subjected to water separation treatment to obtain a water layer and an ethyl acetate layer. The ethyl acetate layer is then reused.

8. The method for recovering ethyl acetate in the production of sulbactamic acid according to claim 7, characterized in that, During the distillation process, the reflux ratio of the distillation column is 1:2-3.

9. The method for recovering ethyl acetate in the production of sulbactamic acid according to claim 7, characterized in that, During the distillation process, distillation waste liquid is obtained in the bottom of the distillation column and is treated together with the water layer as wastewater.

10. A system for recovering ethyl acetate in the production of sulbactamic acid, the system being used to perform the method for recovering ethyl acetate in the production of sulbactamic acid according to any one of claims 1-9, characterized in that, It includes a regulating tank (1), a filter (101), a distillation column (2) and a collection tank (3) connected in sequence. The inlet of the regulating tank (1) is connected to an alkali storage tank (110) and a sodium acetate storage tank (120). The outlet of the regulating tank (1) is connected to the inlet of the filter (101), the outlet of the filter (101) is connected to the upper feed port of the distillation column (2) through the feed pipe (130), the top outlet of the distillation column (2) is connected to the collection tank (3) through the liquid outlet pipe (310), and a condenser (320) is provided on the liquid outlet pipe (310).

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