A process for the production of an electronic grade epichlorohydrin

Abstract

This invention relates to a method for producing electronic-grade epichlorohydrin, comprising steps including chlorination reaction, dichloropropanol separation, cyclization reaction, and purification. This method can produce electronic-grade epichlorohydrin with an epichlorohydrin content of over 99.99%, meeting the quality requirements for high-purity epichlorohydrin in the high-end electronic materials field. Furthermore, the extractant used in this invention can be recycled, resulting in low overall waste generation, high raw material utilization, and excellent economic and environmental benefits.

Description

Technical Field

[0001] This invention belongs to the field of chemical technology, and more specifically, this invention relates to a method for producing electronic-grade epichlorohydrin. Background Technology

[0003] Traditional epichlorohydrin production methods may suffer from insufficient product purity and high impurity content during production, making them unsuitable for applications requiring extremely high purity. This invention addresses this issue by providing an effective method for producing high-purity electronic-grade epichlorohydrin, thus meeting the growing demand for high-quality raw materials in the chemical industry. Through specific process steps and controlled conditions, this method effectively improves product purity and reduces impurity content, demonstrating significant technical advantages and application value.

[0004] Therefore, in order to overcome the shortcomings of existing technologies, it is essential to develop a new route for producing electronic-grade epichlorohydrin. After extensive experimentation and research, the inventors have finally completed this invention. Summary of the Invention

[0005] [Technical problem to be solved] The purpose of this invention is to provide a method for producing electronic-grade epichlorohydrin.

[0006] [Technical Solution] The present invention is achieved through the following technical solution.

[0007] This invention relates to a method for producing electronic-grade epichlorohydrin.

[0008] The production steps of this production method are as follows: A. Chlorination reaction According to the catalyst-to-refined glycerol weight ratio of 1:10~20 and the refined glycerol-to-hydrogen chloride molar ratio of 1:2.0~2.6, refined glycerol from outside the site is sent to the upper part of the premixing tank 1 through a pipeline, and the dicarboxylic acid catalyst is sent to the top of the premixing tank 1 through a pipeline. The refined glycerol and the catalyst are stirred and mixed evenly in the premixing tank 1, and then discharged from the bottom of the premixing tank 1. It is sent to the upper part of the chlorination reactor 3 by the glycerol solution transfer pump 2 and the pipeline. At the same time, hydrogen chloride gas is sent to the lower part of the chlorination reactor 3 through a pipeline. The refined glycerol and hydrogen chloride undergo chlorination reaction for 2~8 hours in the presence of the dicarboxylic acid catalyst at a temperature of 100~130℃ and a pressure of 0.1~1.0MPa. The resulting chlorinated reaction liquid is discharged from the bottom of the chlorination reactor 3, while the unreacted hydrogen chloride gas is discharged from the top of the chlorination reactor 3 and returned to the lower part of the premixing tank 1 through a pipeline. B. Dichloropropanol separation The chlorinated reaction solution obtained in step A is sent to the middle of the dichloropropanol separation tower 5 by the chlorination liquid transfer pump 4. Separation is carried out under conditions of 100-140℃ and 8.0-14.0 kPa. A dichloropropanol aqueous solution containing dichloropropanol, water, hydrogen chloride, and other organic matter is discharged from the top of the dichloropropanol separation tower 5, while a mixture of dicarboxylic acid catalyst and its ester is discharged from the bottom and returned to the chlorination reactor 3 for reuse. The dichloropropanol aqueous solution is then transported via pipeline at a mass ratio of 1:1-10 to the extractant. The extractant is sent to the upper part of the extraction tower 6, while the extractant is sent to the lower part of the extraction tower 6. Extraction is carried out in the extraction tower 6 at an extraction temperature of 10~40℃ for 1~4 hours. Then the extract phase is discharged from the top of the extraction tower 6 and the raffinate phase is discharged from the bottom of the extraction tower 6. The extract phase is sent to the middle part of the solvent recovery tower 7 through a pipeline. Separation is carried out at a top temperature of 60~100℃ and a pressure of 10~60KPa. The solvent and light component mixture is discharged from the top of the solvent recovery tower 7 and the concentrated dichloropropanol solution is discharged from the bottom of the solvent recovery tower 7. C. Cycling reaction The concentrated dichloropropanol solution obtained in step B is sent to the mixer 9 by the dichloropropanol transfer pump 8. At the same time, the liquid alkali is also sent to the mixer 9 through the pipeline. The concentrated dichloropropanol solution and the liquid alkali are mixed evenly and then sent to the upper part of the cyclization reactor 10. The dichloropropanol and the liquid alkali undergo a cyclization reaction at a temperature of 30~80℃ for 5~40 minutes. The crude epichlorohydrin obtained from the cyclization reaction is discharged from the top of the cyclization reactor 10, while the cyclization wastewater is discharged from the bottom of the cyclization reactor 10. D. Refined The crude epichlorohydrin from step C is piped to the middle of the light component removal tower 11, where light components are removed under conditions of a top temperature of 50-70°C and a pressure of 20-40 kPa. The light components are discharged from the top of the light component removal tower 11, while the epichlorohydrin without light components is discharged from the bottom of the light component removal tower 11 and sent by the epichlorohydrin transfer pump 12 to the middle of the product refining tower 13 for refining under conditions of a top temperature of 85-95°C and a pressure of 50-60 kPa. The electronic-grade epichlorohydrin product is discharged from the top of the product refining tower 13.

[0009] According to a preferred embodiment of the present invention, in step A, the refined glycerol contains, by weight, 99.0-99.5% glycerol, 0.01-0.05% sulfated ash, 0.5-0.8% water and 0.01-0.1% free fatty acids; the dicarboxylic acid catalyst is one or more catalysts selected from oxalic acid, malonic acid, succinic acid or adipic acid.

[0010] According to another preferred embodiment of the present invention, in step A, the chlorination reactor 3 is a bubble column type, tubular type or circulating reactor.

[0011] According to another preferred embodiment of the present invention, in step A, the chlorination reaction solution contains, by weight, 50.0-60.0% dichloropropanol, 1.0-2.0% 3-chloro-1,2-propanediol, 10.0-15.0% 2-chloro-1,3-propanediol, 0.01-0.1% glycerol, 9.0-11.0% water, and 6.0-8.0% hydrogen chloride.

[0012] According to another preferred embodiment of the present invention, in step B, the extractant is methyl isobutyl ketone or 1,2-dichloroethane.

[0013] According to another preferred embodiment of the present invention, in step B, the dichloropropanol separation tower 5 is a separation device with internal components of sieve plates, float valves, packing, or bubble caps; the extraction tower 6 is an extraction device with internal components of sieve plates, packing, or rotary discs; and the solvent recovery tower 7 is a recovery device with internal components of float valves, packing, or sieve plates.

[0014] According to another preferred embodiment of the present invention, in step B, the concentrated dichloropropanol solution contains, by weight, 60.0-80.0% dichloropropanol, 0.1-1.0% 2-chloro-1,3-propanediol, 5.0-7.0% water and 15.0-20.0% hydrogen chloride.

[0015] According to another preferred embodiment of the present invention, in step C, the mixer 9 is a static mixer, a jet mixer or a Venturi mixer type mixing device; the cyclization reactor 10 is a plate cyclization tower reaction device.

[0016] According to another preferred embodiment of the present invention, in step D, the light component removal tower 11 is a separation device with float valves, packing or sieve plates as internal components; the product refining tower 13 is a separation device with float valves, packing or sieve plates as internal components.

[0017] According to another preferred embodiment of the present invention, in step D, the electronic-grade epichlorohydrin contains more than 99.99% epichlorohydrin, 0.001-0.005% water, 0.001-0.005% dichloropropanol and 0.001-0.003% chloroacetone by weight.

[0018] The invention will now be described in more detail.

[0019] This invention relates to a method for producing electronic-grade epichlorohydrin. The specific steps of this production method are detailed in the appendix. Figure 1 .

[0020] The steps of this production method are as follows: A. Chlorination reaction According to the catalyst-to-refined glycerol weight ratio of 1:10~20 and the refined glycerol-to-hydrogen chloride molar ratio of 1:2.0~2.6, refined glycerol from outside the site is sent to the upper part of the premixing tank 1 through a pipeline, and the dicarboxylic acid catalyst is sent to the top of the premixing tank 1 through a pipeline. The refined glycerol and the catalyst are stirred and mixed evenly in the premixing tank 1, and then discharged from the bottom of the premixing tank 1. It is sent to the upper part of the chlorination reactor 3 by the glycerol solution transfer pump 2 and the pipeline. At the same time, hydrogen chloride gas is sent to the lower part of the chlorination reactor 3 through a pipeline. The refined glycerol and hydrogen chloride undergo chlorination reaction for 2~8 hours in the presence of the dicarboxylic acid catalyst at a temperature of 100~130℃ and a pressure of 0.1~1.0MPa. The resulting chlorinated reaction liquid is discharged from the bottom of the chlorination reactor 3, while the unreacted hydrogen chloride gas is discharged from the top of the chlorination reactor 3 and returned to the lower part of the premixing tank 1 through a pipeline. The chlorination reaction of refined glycerol with hydrogen chloride in the presence of a dicarboxylic acid catalyst is shown in the following chemical reaction equation (I): In this step, when the weight ratio of catalyst to refined glycerol is 1:10~20 and the molar ratio of refined glycerol to hydrogen chloride is 1:2.0~2.6, the refined glycerol and hydrogen chloride undergo a chlorination reaction in the presence of a dicarboxylic acid catalyst at a temperature of 100~130℃ and a pressure of 0.1~1.0MPa for 2~8h.

[0021] The basic role of the dicarboxylic acid catalyst in this chlorination reaction is to activate the reaction process, increase the effective collision frequency between hydrogen chloride and glycerol molecules, and thus accelerate the chlorination reaction rate. Under the set temperature and pressure reaction conditions, it can promote the chlorination reaction to proceed in the direction of producing dichloropropanol, thereby increasing the final yield of dichloropropanol.

[0022] The dicarboxylic acid catalyst used in this invention is one or more catalysts selected from oxalic acid, malonic acid, succinic acid, or adipic acid. These are all products currently sold on the market, such as products sold by Jinan Century Tongda Chemical Co., Ltd. under the trade name oxalic acid, products sold by Guangzhou Deshui Chemical Co., Ltd. under the trade names malonic acid and succinic acid, or products sold by Shandong Longhui Chemical Co., Ltd. under the trade name adipic acid.

[0023] According to the standard analytical method specified in GB / T13206-2022 "Glycerin", the refined glycerin used in this invention contains 99.0-99.5% glycerin, 0.01-0.05% sulfated ash, 0.5-0.8% water and 0.01-0.1% free fatty acids by weight. Among them, sulfated ash should be understood as the inorganic matter remaining after the refined glycerin sample has undergone specific treatment (first carbonization, then thorough wetting with concentrated sulfuric acid at high temperature and then ignition); free fatty acids should be understood as fatty acid molecules in the refined glycerin that have not combined with glycerol to form esters and are in a free state.

[0024] According to the present invention, under the conditions of the chlorination reaction, if the weight ratio of catalyst to refined glycerol is less than 1:20, there are insufficient catalytically active sites in the reaction system, the chlorination reaction rate will be significantly reduced, and the glycerol conversion rate will not reach the expected level. If the weight ratio of catalyst to refined glycerol is greater than 1:10, it will lead to excessive catalysis in the reaction system, which will not only increase the cost of raw materials but also introduce more impurities, increasing the burden on subsequent separation and purification processes. Therefore, a weight ratio of catalyst to refined glycerol of 1:10 to 20 is suitable, preferably 1:12 to 18, and more preferably 1:14 to 16.

[0025] If the molar ratio of refined glycerol to hydrogen chloride is higher than 1:2.0, the amount of hydrogen chloride used will be insufficient, failing to ensure that glycerol is fully converted into the target dichloropropanol product. If the molar ratio of refined glycerol to hydrogen chloride is lower than 1:2.6, the excess hydrogen chloride will not only fail to improve the glycerol conversion rate but will also increase the hydrogen chloride recovery load, thereby increasing production energy consumption and waste treatment costs. Therefore, a molar ratio of refined glycerol to hydrogen chloride of 1:2.0 to 2.6 is reasonable, preferably 1:2.1 to 2.5, and more preferably 1:2.2 to 2.4.

[0026] In this step, when the catalyst-to-refined glycerol weight ratio, the refined glycerol-to-hydrogen chloride molar ratio, the reaction pressure, and the reaction time are within the specified ranges, if the reaction temperature is below 100°C, the activation energy for the chlorination reaction will be insufficient, resulting in a slow reaction rate and low glycerol conversion. If the reaction temperature is above 130°C, side reactions will be exacerbated, generating more polychlorinated byproducts, reducing the selectivity of the target product dichloropropanol, and increasing the difficulty of subsequent impurity removal. Therefore, a reaction temperature of 100–130°C is suitable, preferably 108–124°C, and more preferably 112–118°C.

[0027] When the catalyst-to-glycerol weight ratio, the glycerol-to-hydrogen chloride molar ratio, the reaction temperature, and the reaction time are within the specified ranges, if the reaction pressure is below 0.1 MPa, the solubility of hydrogen chloride in the reaction solution is low, resulting in insufficient reaction efficiency. If the reaction pressure is above 1.0 MPa, the pressure requirements for the equipment increase, significantly increasing equipment investment and operating costs without resulting in a significant improvement in reaction efficiency. Therefore, a reaction pressure of 0.1–1.0 MPa is appropriate, preferably 0.2–0.8 MPa, and more preferably 0.3–0.6 MPa.

[0028] When the catalyst-to-refined glycerol weight ratio, the refined glycerol-to-hydrogen chloride molar ratio, the reaction temperature, and the reaction pressure are within the specified ranges, if the reaction time is less than 2 hours, the glycerol will not fully participate in the reaction, the conversion rate will not meet the requirements, and the overall production yield will be reduced. If the reaction time is longer than 8 hours, the reaction has approached equilibrium, and further extending the reaction time will not only fail to improve the glycerol conversion rate and dichloropropanol yield, but will also increase the probability of side reactions and reduce the production capacity of the unit per unit time. Therefore, a reaction time of 2 to 8 hours is desirable, preferably 3 to 7 hours, and more preferably 4 to 6 hours.

[0029] Preferably, when the weight ratio of catalyst to refined glycerol is 1:12~18 and the molar ratio of refined glycerol to hydrogen chloride is 1:2.1~2.5, the chlorination reaction of refined glycerol and hydrogen chloride is carried out in the presence of a dicarboxylic acid catalyst at a temperature of 108~124℃ and a pressure of 0.2~0.8MPa for 3~7h.

[0030] More preferably, when the weight ratio of catalyst to refined glycerol is 1:14~16 and the molar ratio of refined glycerol to hydrogen chloride is 1:2.2~2.4, the chlorination reaction of refined glycerol and hydrogen chloride is carried out in the presence of a dicarboxylic acid catalyst at a temperature of 112~118℃ and a pressure of 0.3~0.6MPa for 4~6h.

[0031] According to the gas chromatography internal standard method, Karl Fischer method and acid-base neutralization titration method, the chlorinated reaction solution contains, by weight, 50.0-60.0% dichloropropanol, 1.0-2.0% 3-chloro-1,2-propanediol, 10.0-15.0% 2-chloro-1,3-propanediol, 0.01-0.1% glycerol, 9.0-11.0% water and 6.0-8.0% hydrogen chloride.

[0032] The chlorination reactor 3 used in step A of this invention is a bubble column reactor, a tubular reactor, or a circulating reactor. These are all products currently sold on the market. For example, the bubble column reactor sold by Xuchang Ruitaifeng Technology Co., Ltd. under the trade name bubble reactor, the tubular reactor sold by Nantong Jianghan Petrochemical Equipment Co., Ltd. under the trade name tubular reactor, and the circulating reactor sold by Shanghai Donggeng Chemical Co., Ltd. under the trade name circulating reactor.

[0033] The premixing tank 1 used in step A of this invention is a mixing device commonly used in the field of chemical technology; the glycerol solution transfer pump 2 used in step A of this invention is a liquid transfer device commonly used in the field of chemical technology.

[0034] B. Dichloropropanol separation The chlorinated reaction solution obtained in step A is sent to the middle of the dichloropropanol separation tower 5 by the chlorination liquid transfer pump 4. Separation is carried out under conditions of 100-140℃ and 8.0-14.0 kPa. A dichloropropanol aqueous solution containing dichloropropanol, water, hydrogen chloride, and other organic matter is discharged from the top of the dichloropropanol separation tower 5, while a mixture of dicarboxylic acid catalyst and its ester is discharged from the bottom and returned to the chlorination reactor 3 for reuse. The dichloropropanol aqueous solution is then transported via pipeline at a mass ratio of 1:1-10 to the extractant. The extractant is sent to the upper part of the extraction tower 6, while the extractant is sent to the lower part of the extraction tower 6. Extraction is carried out in the extraction tower 6 at an extraction temperature of 10~40℃ for 1~4 hours. Then the extract phase is discharged from the top of the extraction tower 6 and the raffinate phase is discharged from the bottom of the extraction tower 6. The extract phase is sent to the middle part of the solvent recovery tower 7 through a pipeline. Separation is carried out at a top temperature of 60~100℃ and a pressure of 10~60KPa. The solvent and light component mixture is discharged from the top of the solvent recovery tower 7 and the concentrated dichloropropanol solution is discharged from the bottom of the solvent recovery tower 7. The main role of the dichloropropanol separation step in the electronic-grade epichlorohydrin production method of this invention is to effectively separate the dichloropropanol product from unreacted raw materials, catalysts, and by-products. On the one hand, it recovers and recycles the incompletely reacted raw materials and the stable dicarboxylic acid catalyst, reducing raw material consumption and production costs, and improving the overall economic efficiency of the process. On the other hand, it removes residual acidic components and organic impurities from the system, preventing impurities from entering the subsequent cyclization process and affecting the purity and yield of the product.

[0035] The chlorinated reaction solution obtained in step A is separated in dichloropropanol separation tower 5 at a temperature of 100-140°C and a pressure of 8.0-14.0 kPa to obtain a mixture of dichloropropanol aqueous solution and dicarboxylic acid catalyst. When the pressure in dichloropropanol separation tower 5 is within the aforementioned range, if the separation temperature is below 100°C, the dichloropropanol volatilization effect will not meet the requirements, and it cannot be effectively separated from the reaction solution, leading to a decrease in the dichloropropanol yield. If the separation temperature is above 140°C, some byproducts in the system will evaporate along with the dichloropropanol, and the thermal decomposition of dichloropropanol itself will be aggravated, thus reducing the purity of the separated dichloropropanol. Therefore, a separation temperature of 100-140°C is suitable, preferably 108-134°C, and more preferably 114-128°C. When the temperature of the dichloropropanol separation tower 5 is within the aforementioned range, if its separation pressure is below 8.0 kPa, the performance requirements for the vacuum equipment will increase significantly, the energy consumption of the unit will increase significantly, and the production cost will rise sharply. If its separation pressure is above 14.0 kPa, a higher separation temperature is required to achieve effective separation of dichloropropanol from the tower bottom components, which will also increase energy consumption and increase the risk of by-product distillation and dichloropropanol decomposition. Therefore, a separation pressure of 8.0~14.0 kPa is reasonable, preferably 8.8~13.2 kPa, and more preferably 9.4~12.8 kPa. Preferably, the chlorinated reaction solution is separated in the dichloropropanol separation tower 5 at a temperature of 108~134℃ and a pressure of 8.8~13.2KPa to obtain a mixture of dichloropropanol aqueous solution and organic acid catalyst.

[0036] More preferably, the chlorinated reaction solution is separated in the dichloropropanol separation tower 5 at a temperature of 114~128℃ and a pressure of 9.4~12.8KPa to obtain a mixture of dichloropropanol aqueous solution and organic acid catalyst.

[0037] According to the gas chromatography internal standard method, Karl Fischer method and acid-base neutralization titration method, the dichloropropanol aqueous solution discharged from the top of the dichloropropanol separation tower 5 contains dichloropropanol, water, hydrogen chloride and other organic matter, while the product discharged from the bottom of the tower is an organic acid catalyst and its ester mixture, which is returned to the chlorination reactor 3 for reuse.

[0038] The dichloropropanol separation tower 5 used in this invention is a separation device with internal components of sieve plates, floating valves, packing, or bubble caps. These are all products currently sold on the market. For example, sieve plate separation devices sold by Tianjin Huizhu Hengsheng Technology Co., Ltd. under the trade name sieve plate tray, floating valve separation devices sold by Shandong Zhongsheng Precision Technology Co., Ltd. under the trade name floating valve tray, packing separation devices sold by Nantong Sansheng Graphite Equipment Technology Co., Ltd. under the trade name ST type graphite packed tower, and bubble cap separation devices sold by Hebei Huiheng Distillation Technology Co., Ltd. under the trade name bubble cap tray. The dichloropropanol aqueous solution and the extractant are extracted in extraction tower 6 at a mass ratio of 1:1~10 and an extraction temperature of 10~40℃ for 1~4 hours.

[0039] The extractant used in this invention is methyl isobutyl ketone or 1,2-dichloroethane, both of which are currently commercially available products, such as those sold by Jinan Century Tongda Chemical Co., Ltd. under the trade name methyl isobutyl ketone, and those sold by Shanghai Nanmu Chemical Co., Ltd. under the trade name 1,2-dichloroethane.

[0040] In this invention, when the extraction temperature and extraction time are within the specified range, if the mass ratio of dichloropropanol aqueous solution to extractant is higher than 1:1, the amount of extractant is insufficient, and dichloropropanol cannot be completely extracted, resulting in a reduced product yield. If the mass ratio of dichloropropanol aqueous solution to extractant is lower than 1:10, the amount of extractant is excessive, increasing solvent recovery energy consumption and cost without improving extraction efficiency. Therefore, the mass ratio of dichloropropanol aqueous solution to extractant is 1:1 to 10; preferably 1:3 to 8, and more preferably 1:4 to 6.

[0041] When the mass ratio of dichloropropanol aqueous solution to extractant and the extraction time are within the specified range, if the extraction temperature is below 10°C, the solubility and fluidity of dichloropropanol in the extractant decreases, the extraction partition coefficient decreases, and efficient extraction and separation cannot be achieved. If the extraction temperature is above 40°C, the volatilization loss of the extractant increases, not only causing solvent loss and increasing production costs, but also easily triggering the volatilization of organic pollutants on site, increasing the pressure on safety and environmental protection management. Therefore, an extraction temperature of 10~40°C is appropriate, preferably 16~34°C, and more preferably 20~30°C.

[0042] When the mass ratio of dichloropropanol aqueous solution to extractant and the extraction temperature are within the specified range, if the extraction time is less than 1 hour, sufficient interphase mass transfer of dichloropropanol cannot be achieved in the extraction tower, resulting in incomplete extraction and a significant decrease in the dichloropropanol yield. If the extraction time exceeds 4 hours, it will reduce the processing capacity of the extraction tower, increase the production time per unit product, reduce overall production efficiency, and not contribute to further improvement of extraction efficiency. Therefore, an extraction time of 1 to 4 hours is appropriate, preferably 1.6 to 3.4 hours, and more preferably 2.0 to 3.0 hours.

[0043] Preferably, the dichloropropanol aqueous solution and the extractant are extracted in the extraction tower 6 at a mass ratio of 1:3~8 and an extraction temperature of 16~34℃ for 1.6~3.4h.

[0044] More preferably, the dichloropropanol aqueous solution and the extractant are extracted in the extraction tower 6 at a mass ratio of 1:4~6 and an extraction temperature of 20~30℃ for 2.0~3.0h.

[0045] The extraction tower 6 used in this invention is an extraction device with internal components of sieve plates, packing, or rotary discs. These are all products currently sold on the market, such as the sieve plate extraction device sold by Wenzhou Yurun Machinery Technology Co., Ltd. under the trade name "periodic high-efficiency sieve plate extraction tower", the packing type extraction device sold by Zhejiang Shuangzi Intelligent Equipment Co., Ltd. under the trade name "extraction tower", and the rotary disc extraction device sold by Jiangsu Zhengfen Technology Co., Ltd. under the trade name "turbine rotary disc extraction tower". The extract phase discharged from the top of extraction column 6 is separated in solvent recovery column 7 under conditions of a top temperature of 60-100°C and a pressure of 10-60 kPa. When the pressure inside solvent recovery column 7 is within the aforementioned range, if the top temperature is below 60°C, the extractant cannot be completely vaporized and distilled off, resulting in incomplete solvent recovery, which leads to a decrease in extractant recovery rate and an increase in production costs. If the top temperature is above 100°C, a small amount of dichloropropanol will also be distilled off along with the extractant, causing not only a loss of dichloropropanol but also affecting the purity of the recovered extractant, leading to a decrease in the efficiency of subsequent extraction processes. Therefore, a top temperature of 60-100°C is feasible, preferably 68-90°C, and more preferably 76-84°C. When the top temperature of the column is within the specified range, if the pressure inside the solvent recovery column 7 is below 10 kPa, it will increase the requirements for the vacuum performance of the equipment and significantly increase the energy consumption of the unit. If the pressure inside the solvent recovery column 7 is above 60 kPa, a higher top temperature is required to achieve full recovery of the extractant, which will also lead to increased energy consumption and dichloropropanol loss. Therefore, a pressure of 10-60 kPa inside the solvent recovery column 7 is suitable, preferably 18-54 kPa, and more preferably 25-46 kPa. Preferably, the extract phase discharged from the top of the extraction tower 6 is separated in the solvent recovery tower 7 under the conditions of a top temperature of 68~90℃ and a pressure of 18~54KPa.

[0046] More preferably, the extract phase discharged from the top of the extraction tower 6 is separated in the solvent recovery tower 7 under the conditions of a top temperature of 76~84°C and a pressure of 25~46 kPa.

[0047] The solvent recovery tower 7 used in this invention is a recovery device with internal components of a floating valve, packing, or sieve plate. These are all products currently sold on the market. For example, the floating valve type recovery device sold by Shandong Zhong Sheng Precision Technology Co., Ltd. under the trade name Floating Valve Tray, the packing type recovery device sold by Hebei Huiheng Distillation Technology Co., Ltd. under the trade name Metal Structured Packing, and the sieve plate type recovery device sold by Tianjin Huizhu Hengsheng Technology Co., Ltd. under the trade name Sieve Plate Tray.

[0048] The extract phase is separated in solvent recovery tower 7, with the solvent and light component mixture discharged from the top and the concentrated dichloropropanol solution discharged from the bottom. According to the gas chromatography internal standard method, Karl Fischer method and acid-base neutralization titration method, the concentrated dichloropropanol solution contains 60.0-80.0% dichloropropanol, 0.1-1.0% 2-chloro-1,3-propanediol, 5.0-7.0% water and 15.0-20.0% hydrogen chloride by weight.

[0049] The chlorinated liquid transfer pump 4 used in this step is a commonly used transfer pump in the field of chemical technology.

[0050] C. Cycling reaction The concentrated dichloropropanol solution obtained from step B is sent to the mixer 9 by the dichloropropanol transfer pump 8. At the same time, the liquid alkali is also sent to the mixer 9 through the pipeline. The concentrated dichloropropanol solution and the liquid alkali are mixed evenly and then sent to the upper part of the cyclization reactor 10. The concentrated dichloropropanol solution and the liquid alkali undergo a cyclization reaction at a temperature of 30~80℃ for 5~40 minutes. The crude epichlorohydrin obtained from the cyclization reaction is discharged from the top of the cyclization reactor 10, while the cyclization wastewater is discharged from the bottom of the cyclization reactor 10. In this step, the cyclization reaction equation between the concentrated dichloropropanol solution and the liquid alkali is as follows: According to the present invention, the liquid alkali should be understood to be an aqueous solution of sodium hydroxide with a concentration of 15-25% by weight, which are commonly used products in the field of chemical technology.

[0051] According to the present invention, concentrated dichloropropanol solution and liquid alkali are subjected to a cyclization reaction at a temperature of 30~80°C for 5~40 min.

[0052] In this step, when the cyclization reaction time is within the specified range, if the cyclization reaction temperature is below 30°C, the reaction rate will decrease significantly, resulting in a large amount of dichloropropanol not being converted. This will ultimately lead to a decrease in the epichlorohydrin yield. At the same time, the unreacted dichloropropanol will enter subsequent processes, increasing the difficulty of impurity separation and affecting the purity of the final product. If the cyclization reaction temperature is above 80°C, the reaction rate will be too fast, and the side reactions will also be aggravated, generating more byproducts. This will also reduce the epichlorohydrin yield and increase the load on subsequent separation and purification processes. Therefore, a cyclization reaction temperature of 30~80°C is appropriate, preferably 38~72°C, and more preferably 45~66°C. When the cyclization reaction temperature is within the aforementioned range, if the cyclization reaction time is less than 5 min, the dichloropropanol reaction will be insufficient and the conversion will be incomplete, similar to the negative effects of low temperature. If the cyclization reaction time is longer than 40 min, it will not only increase the probability of side reactions and reduce product yield, but also prolong the production cycle, reduce the unit time processing capacity of the device, and lower the overall production efficiency. Therefore, a cyclization reaction time of 5 to 40 min is appropriate, preferably 12 to 34 min, and more preferably 18 to 28 min. Preferably, the concentrated dichloropropanol solution and liquid alkali are subjected to a cyclization reaction at a temperature of 38~72℃ for 12~34 min.

[0053] More preferably, the concentrated dichloropropanol solution and liquid alkali are subjected to a cyclization reaction at a temperature of 45~66℃ for 18~28 min.

[0054] According to gas chromatography and Karl Fischer method, the crude epichlorohydrin obtained by this cyclization reaction step contains 95.0-97.0% epichlorohydrin, 1.2-2.0% water, 0.1-0.2% acrolein, 1.5-2.5% dichloropropanol and 0.1-0.2% other organic matter by weight.

[0055] The mixer 9 used in this invention is a static mixer, jet mixer, or Venturi mixer type mixing equipment, which are all products currently sold on the market. For example, the static mixer sold by Qidong Xingmei Machinery Factory under the trade name static mixer, the jet mixer sold by Shanghai Chenpai Petrochemical Equipment Co., Ltd. under the trade name jet mixer, and the Venturi mixer sold by Shenyang Northern Technology Co., Ltd. under the trade name Venturi jet mixer. The cyclization reactor 10 used in this invention is a plate cyclization tower reaction device, which is a product currently sold on the market, such as the plate cyclization tower reaction device sold by Wuxi Nanquan Hongda Reaction Tower Equipment Factory under the trade name reactor.

[0056] The dichloropropanol transfer pump 8 used in this invention is a product commonly used in the field of chemical technology and currently available on the market.

[0057] D. Refined The crude epichlorohydrin from step C is piped to the middle of the light component removal tower 11, where light components are removed under conditions of a top temperature of 50-70°C and a pressure of 20-40 kPa. The light components are discharged from the top of the light component removal tower 11, while the epichlorohydrin without light components is discharged from the bottom of the light component removal tower 11 and sent by the epichlorohydrin transfer pump 12 to the middle of the product refining tower 13 for refining under conditions of a top temperature of 85-95°C and a pressure of 50-60 kPa. The electronic-grade epichlorohydrin product is discharged from the top of the product refining tower 13.

[0058] In this step, the crude epichlorohydrin is first treated to remove light components before purification. This segmented treatment aims to prevent light components from prematurely contaminating the final product and affecting the purity of the epichlorohydrin product. It also reduces the interference of light components on the purification tower separation process, ensuring stable operation of the purification process. The light components mainly consist of water, acrolein, 2-chloropropenol, and dichloropropane.

[0059] The crude epichlorohydrin is subjected to a light component removal process in column 11 at a top temperature of 50-70°C and a pressure of 20-40 kPa to remove its light components. When the pressure for light component removal is within this range, if the top temperature is below 50°C, the light components are difficult to fully vaporize and distill out, making complete separation from the crude epichlorohydrin impossible. The remaining light components will be carried into subsequent refining processes, affecting the purity of the final product. If the top temperature is above 70°C, some epichlorohydrin will also be distilled out along with the light components, reducing the final product yield and increasing material loss, leading to higher production costs. Therefore, a top temperature of 50-70°C for light component removal is reasonable, preferably 54-66°C, and more preferably 56-64°C. When the temperature for removing light components is within the aforementioned range, if the pressure for removing light components is below 20 kPa, the excessively high vacuum level will significantly increase the operating load of the vacuum equipment, increasing the energy consumption and maintenance costs of the device. If the pressure for removing light components is above 40 kPa, a higher temperature is required to achieve complete removal of the light components, which will also lead to increased energy consumption and the loss of epichlorohydrin due to the distillation of light components. Therefore, a pressure of 20-40 kPa for removing light components is feasible, preferably 24-36 kPa, and more preferably 28-32 kPa. According to gas chromatography and Karl Fischer method, the electronic grade epichlorohydrin contains more than 99.99% epichlorohydrin, 0.001-0.005% water, 0.001-0.005% dichloropropanol and 0.001-0.003% chloroacetone by weight.

[0060] In step D, the light component removal tower 11 is a tower internals of a floating valve, packing or sieve plate type separation device, which are all products currently sold on the market, such as floating valve type separation device, packing type separation device, and sieve plate type separation device sold by ………. Company under the trade name ………; The product refining tower 13 is a separation device with internal components of floating valves, packing, or sieve plates. These are all products currently sold on the market, such as floating valve type separation devices, packing type separation devices, and sieve plate type separation devices sold by Wuxi Pengmao Chemical Equipment Co., Ltd. under the trade name distillation tower.

[0061] [Beneficial Effects] Compared with existing technologies, this invention has the following main advantages: Through a process route of chlorination reaction-extraction separation of dichloropropanol-cyclization reaction-multi-stage purification, combined with specific process parameter control at each step, this invention can efficiently remove various impurities from the crude product, ultimately obtaining electronic-grade epichlorohydrin with a purity of over 99.99%, meeting the requirements of high-end electronic materials. This enables domestic mass production and supply of electronic-grade epichlorohydrin, effectively reducing raw material costs for downstream semiconductor and high-end PCB industries, and ensuring the safety and stability of the industrial chain and supply chain. Furthermore, the extractant in this invention's process can be recycled, resulting in low waste generation and high atom utilization, demonstrating excellent economic and environmental benefits. Attached Figure Description Figure 1 This is a schematic diagram of the process flow for the production method of electronic-grade epichlorohydrin according to the present invention; In the picture: 1-Premixing tank, 2-Glycerol solution transfer pump, 3-Chlorination reactor, 4-Chlorinated liquid transfer pump, 5-Dichloropropanol separation tower, 6-Extraction tower, 7-Solvent recovery tower, 8-Dichloropropanol transfer pump, 9-Mixer, 10-Circulation reactor, 11-Light component removal tower, 12-Epoxychloropropane transfer pump, 13-Product purification tower. Detailed Implementation The invention will be better understood through the following examples.

[0062] Example 1: Method for producing electronic-grade epichlorohydrin according to the present invention The implementation method of this embodiment is as follows: A. Chlorination reaction This embodiment uses refined glycerol produced by Ningbo Huanyang New Material Co., Ltd., which contains 99.16% glycerol, 0.03% sulfated ash, 0.80% moisture and 0.01% free fatty acids by weight.

[0063] According to the catalyst to refined glycerol weight ratio of 1:17 and the refined glycerol to hydrogen chloride molar ratio of 1:2.0, refined glycerol from outside the site is sent to the upper part of the premixing tank 1 through a pipeline. The oxalic acid dicarboxylic acid catalyst is sent to the top of the premixing tank 1 through a pipeline. The refined glycerol and the catalyst are stirred and mixed evenly in the premixing tank 1, and then discharged from the bottom of the premixing tank 1. The glycerol solution is sent to the upper part of the chlorination reactor 3 through the glycerol solution transfer pump 2 and pipeline. At the same time, hydrogen chloride gas is sent to the lower part of the chlorination reactor 3 through a pipeline. The refined glycerol and hydrogen chloride undergo a chlorination reaction for 4 hours at a temperature of 120°C and a pressure of 0.4 MPa in the presence of the oxalic acid dicarboxylic acid catalyst. The resulting chlorinated reaction liquid is discharged from the bottom of the chlorination reactor 3, while the unreacted hydrogen chloride gas is discharged from the top of the chlorination reactor 3 and returned to the lower part of the premixing tank 1 through a pipeline. B. Dichloropropanol separation The chlorinated reaction solution obtained in step A is sent to the middle of the dichloropropanol separation tower 5 by the chlorination liquid transfer pump 4. Separation is carried out under conditions of 140℃ and 8.0KPa. A dichloropropanol aqueous solution containing dichloropropanol, water, hydrogen chloride, and other organic matter is discharged from the top of the dichloropropanol separation tower 5, while a mixture of oxalic acid dicarboxylic acid catalyst and its ester is discharged from the bottom of the tower and returned to the chlorination reactor 3 for reuse. The dichloropropanol aqueous solution is sent to the upper part of the extraction tower 6 via a pipeline at a mass ratio of 1:7 to the extractant. Simultaneously, the methyl isobutyl ketone extractant is sent to the lower part of the extraction tower 6. Extraction was carried out at an extraction temperature of 10°C for 4 hours. The extract phase was then discharged from the top of extraction tower 6, and the raffinate phase was discharged from the bottom of extraction tower 6. The extract phase was sent to the middle of solvent recovery tower 7 through a pipeline, where it was separated at a top temperature of 100°C and a pressure of 10 kPa. The solvent and light component mixture was discharged from the top of solvent recovery tower 7, and the concentrated dichloropropanol solution was discharged from the bottom of solvent recovery tower 7. According to the method described in this application, the concentrated dichloropropanol solution contained 74.5% dichloropropanol, 1.0% 2-chloro-1,3-propanediol, 5.6% water, and 18.5% hydrogen chloride by weight.

[0064] C. Cycling reaction The concentrated dichloropropanol solution obtained from step B is sent to the mixer 9 by the dichloropropanol transfer pump 8. At the same time, the liquid alkali with a concentration of 15% by weight is also sent to the mixer 9 by the pipeline. The concentrated dichloropropanol solution and the liquid alkali are mixed evenly and then sent to the upper part of the cyclization reactor 10. The concentrated dichloropropanol solution and the liquid alkali are subjected to a cyclization reaction at a temperature of 80°C for 5 minutes. The crude epichlorohydrin obtained from the cyclization reaction is discharged from the top of the cyclization reactor 10, while the cyclization wastewater is discharged from the bottom of the cyclization reactor 10. D. Refined The crude epichlorohydrin from step C is piped to the middle of the light component removal tower 11, where light components are removed under the conditions of a tower top temperature of 70°C and a pressure of 34 kPa. The light components are discharged from the top of the light component removal tower 11, while the epichlorohydrin with the light components removed is discharged from the bottom of the light component removal tower 11 and sent by the epichlorohydrin transfer pump 12 to the middle of the product refining tower 13 for refining under the conditions of a tower top temperature of 92°C and a pressure of 53 kPa. The electronic-grade epichlorohydrin product is discharged from the top of the product refining tower 13.

[0065] According to the analytical method described in this application, the electronic-grade epichlorohydrin prepared in this embodiment contains 99.998% epichlorohydrin, 0.005% water, 0.002% dichloropropanol and 0.002% chloroacetone by weight.

[0066] Example 2: Method for producing electronic-grade epichlorohydrin according to the present invention The implementation method of this embodiment is as follows: A. Chlorination reaction This embodiment uses refined glycerol produced by Ningbo Huanyang New Material Co., Ltd., which contains 99.22% glycerol, 0.01% sulfated ash, 0.70% moisture and 0.07% free fatty acids by weight.

[0067] According to the catalyst to refined glycerol weight ratio of 1:10 and the refined glycerol to hydrogen chloride molar ratio of 1:2.6, refined glycerol from outside the site is sent to the upper part of the premixing tank 1 through a pipeline. The malondicarboxylic acid catalyst is sent to the top of the premixing tank 1 through a pipeline. The refined glycerol and the catalyst are stirred and mixed evenly in the premixing tank 1, and then discharged from the bottom of the premixing tank 1. The glycerol solution is sent to the upper part of the chlorination reactor 3 through the glycerol solution transfer pump 2 and pipeline. At the same time, hydrogen chloride gas is sent to the lower part of the chlorination reactor 3 through a pipeline. The refined glycerol and hydrogen chloride undergo a chlorination reaction for 8 hours at a temperature of 100℃ and a pressure of 0.1MPa in the presence of the organic dicarboxylic acid catalyst. The resulting chlorinated reaction liquid is discharged from the bottom of the chlorination reactor 3, while the unreacted hydrogen chloride gas is discharged from the top of the chlorination reactor 3 and returned to the lower part of the premixing tank 1 through a pipeline. B. Dichloropropanol separation The chlorinated reaction solution obtained in step A is sent to the middle of the dichloropropanol separation tower 5 by the chlorination liquid transfer pump 4. Separation is carried out under conditions of 112℃ and 10.0KPa. A dichloropropanol aqueous solution containing dichloropropanol, water, hydrogen chloride, and other organic matter is discharged from the top of the dichloropropanol separation tower 5, while a mixture of malonic acid dicarboxylic acid catalyst and its ester is discharged from the bottom and returned to the chlorination reactor 3 for reuse. The dichloropropanol aqueous solution is sent to the upper part of the extraction tower 6 via pipeline at a mass ratio of 1:1 to the extractant, while 1,2-dichloroethane extractant is sent to the lower part of the extraction tower 6. During the extraction process... Extraction is carried out in column 6 at an extraction temperature of 20°C for 3 hours. The extract phase is then discharged from the top of column 6, and the raffinate phase is discharged from the bottom of column 6. The extract phase is sent to the middle of solvent recovery column 7 through a pipeline and separated at a top temperature of 60°C and a pressure of 25 kPa. The solvent and light component mixture is discharged from the top of solvent recovery column 7, and the concentrated dichloropropanol solution is discharged from the bottom of solvent recovery column 7. According to the method described in this application, the concentrated dichloropropanol solution contains 60.0% dichloropropanol, 0.1% 2-chloro-1,3-propanediol, 5.0% water, and 15.0% hydrogen chloride by weight.

[0068] C. Cycling reaction The concentrated dichloropropanol solution obtained from step B is sent to the mixer 9 by the dichloropropanol transfer pump 8. At the same time, the liquid alkali with a concentration of 25% by weight is also sent to the mixer 9 by pipeline. The concentrated dichloropropanol solution and the liquid alkali are mixed evenly and then sent to the upper part of the cyclization reactor 10. The concentrated dichloropropanol solution and the liquid alkali undergo a cyclization reaction at a temperature of 30°C for 40 minutes. The crude epichlorohydrin obtained from the cyclization reaction is discharged from the top of the cyclization reactor 10, while the cyclization wastewater is discharged from the bottom of the cyclization reactor 10. D. Refined The crude epichlorohydrin from step C is piped to the middle of the light component removal tower 11, where light components are removed under the conditions of a tower top temperature of 50°C and a pressure of 20 kPa. The light components are discharged from the top of the light component removal tower 11, while the epichlorohydrin with the light components removed is discharged from the bottom of the light component removal tower 11 and sent by the epichlorohydrin transfer pump 12 to the middle of the product refining tower 13 for refining under the conditions of a tower top temperature of 85°C and a pressure of 58 kPa. The electronic-grade epichlorohydrin product is discharged from the top of the product refining tower 13.

[0069] According to the analytical method described in this application, the electronic-grade epichlorohydrin prepared in this embodiment contains 99.995% epichlorohydrin, 0.001% water, 0.005% dichloropropanol and 0.001% chloroacetone by weight.

[0070] Example 3: Method for producing electronic-grade epichlorohydrin according to the present invention The implementation method of this embodiment is as follows: A. Chlorination reaction This embodiment uses refined glycerol produced by Ningbo Huanyang New Material Co., Ltd., which contains 99.40% glycerol, 0.05% sulfated ash, 0.52% moisture and 0.03% free fatty acids by weight.

[0071] According to the catalyst to refined glycerol weight ratio of 1:20 and the refined glycerol to hydrogen chloride molar ratio of 1:2.2, refined glycerol from outside the site is sent to the upper part of the premixing tank 1 through a pipeline. The succinic acid dicarboxylic acid catalyst is sent to the top of the premixing tank 1 through a pipeline. The refined glycerol and the catalyst are stirred and mixed evenly in the premixing tank 1, and then discharged from the bottom of the premixing tank 1. It is sent to the upper part of the chlorination reactor 3 by the glycerol solution transfer pump 2 and pipeline. At the same time, hydrogen chloride gas is sent to the lower part of the chlorination reactor 3 through a pipeline. The refined glycerol and hydrogen chloride undergo chlorination reaction for 2 hours at a temperature of 130℃ and a pressure of 1.0MPa in the presence of the organic dicarboxylic acid catalyst. The resulting chlorinated reaction liquid is discharged from the bottom of the chlorination reactor 3, while the unreacted hydrogen chloride gas is discharged from the top of the chlorination reactor 3 and returned to the lower part of the premixing tank 1 through a pipeline. B. Dichloropropanol separation The chlorinated reaction solution obtained in step A is sent to the middle of the dichloropropanol separation tower 5 by the chlorination liquid transfer pump 4. Separation is carried out under conditions of 100℃ and 14.0KPa. A dichloropropanol aqueous solution containing dichloropropanol, water, hydrogen chloride, and other organic matter is discharged from the top of the dichloropropanol separation tower 5, while a mixture of succinic acid dicarboxylic acid catalyst and its ester is discharged from the bottom of the tower and returned to the chlorination reactor 3 for reuse. The dichloropropanol aqueous solution is sent to the upper part of the extraction tower 6 via pipeline at a mass ratio of 1:10 to the extractant, while the methyl isobutyl ketone extractant is sent to the lower part of the extraction tower 6. Extraction was carried out at an extraction temperature of 30°C for 2 hours. The extract phase was then discharged from the top of extraction tower 6, and the raffinate phase was discharged from the bottom of extraction tower 6. The extract phase was sent to the middle of solvent recovery tower 7 through a pipeline and separated under the conditions of a top temperature of 75°C and a pressure of 45 kPa. The solvent and light component mixture was discharged from the top of solvent recovery tower 7, and the concentrated dichloropropanol solution was discharged from the bottom of solvent recovery tower 7. According to the method described in this application, the concentrated dichloropropanol solution contained 66.8% dichloropropanol, 0.4% 2-chloro-1,3-propanediol, 7.0% water and 20.0% hydrogen chloride by weight.

[0072] C. Cycling reaction The concentrated dichloropropanol solution obtained from step B is sent to the mixer 9 by the dichloropropanol transfer pump 8. At the same time, the liquid alkali with a concentration of 20% by weight is also sent to the mixer 9 by the pipeline. The concentrated dichloropropanol solution and the liquid alkali are mixed evenly and then sent to the upper part of the cyclization reactor 10. The concentrated dichloropropanol solution and the liquid alkali are subjected to a cyclization reaction at a temperature of 48°C for 15 minutes. The crude epichlorohydrin obtained from the cyclization reaction is discharged from the top of the cyclization reactor 10, while the cyclization wastewater is discharged from the bottom of the cyclization reactor 10. D. Refined The crude epichlorohydrin from step C is piped to the middle of the light component removal tower 11, where light components are removed under the conditions of a tower top temperature of 56°C and a pressure of 26 kPa. The light components are discharged from the top of the light component removal tower 11, while the epichlorohydrin with the light components removed is discharged from the bottom of the light component removal tower 11 and sent by the epichlorohydrin transfer pump 12 to the middle of the product refining tower 13 for refining under the conditions of a tower top temperature of 88°C and a pressure of 60 kPa. The electronic-grade epichlorohydrin product is discharged from the top of the product refining tower 13.

[0073] According to the analytical method described in this application, the electronic-grade epichlorohydrin prepared in this embodiment contains 99.992% epichlorohydrin, 0.002% water, 0.001% dichloropropanol and 0.003% chloroacetone by weight.

[0074] Example 4: Method for producing electronic-grade epichlorohydrin according to the present invention The implementation method of this embodiment is as follows: A. Chlorination reaction This embodiment uses refined glycerol produced by Ningbo Huanyang New Material Co., Ltd., which contains 99.26% glycerol, 0.04% sulfated ash, 0.60% moisture and 0.10% free fatty acids by weight.

[0075] According to the catalyst to refined glycerol weight ratio of 1:14 and the refined glycerol to hydrogen chloride molar ratio of 1:2.4, refined glycerol from outside the site is sent to the upper part of the premixing tank 1 through a pipeline. The adipic acid dicarboxylic acid catalyst is sent to the top of the premixing tank 1 through a pipeline. The refined glycerol and the catalyst are stirred and mixed evenly in the premixing tank 1, and then discharged from the bottom of the premixing tank 1. The glycerol solution is sent to the upper part of the chlorination reactor 3 through the glycerol solution transfer pump 2 and pipeline. At the same time, hydrogen chloride gas is sent to the lower part of the chlorination reactor 3 through a pipeline. The refined glycerol and hydrogen chloride undergo chlorination reaction for 6 hours at a temperature of 110℃ and a pressure of 0.6MPa in the presence of the organic dicarboxylic acid catalyst. The resulting chlorinated reaction liquid is discharged from the bottom of the chlorination reactor 3, while the unreacted hydrogen chloride gas is discharged from the top of the chlorination reactor 3 and returned to the lower part of the premixing tank 1 through a pipeline. B. Dichloropropanol separation The chlorinated reaction solution obtained in step A is sent to the middle of the dichloropropanol separation tower 5 by the chlorination liquid transfer pump 4. Separation is carried out at a temperature of 128℃ and a pressure of 12.0 kPa. A dichloropropanol aqueous solution containing dichloropropanol, water, hydrogen chloride, and other organic matter is discharged from the top of the dichloropropanol separation tower 5, while a mixture of adipic acid dicarboxylic acid catalyst and its ester is discharged from the bottom and returned to the chlorination reactor 3 for reuse. The dichloropropanol aqueous solution is sent to the upper part of the extraction tower 6 by pipeline at a mass ratio of 1:3 to the extractant. Simultaneously, 1,2-dichloroethane extractant is sent to the lower part of the extraction tower 6. Extraction is carried out in the extraction tower 6 at an extraction temperature of 40℃ for 1 hour. Then… The extract phase is discharged from the top of extraction tower 6, and the raffinate phase is discharged from the bottom of extraction tower 6. The extract phase is sent to the middle of solvent recovery tower 7 through a pipeline and separated under the conditions of a top temperature of 85°C and a pressure of 60 kPa. The solvent and light component mixture is discharged from the top of solvent recovery tower 7, and the concentrated dichloropropanol solution is discharged from the bottom of solvent recovery tower 7. According to the method described in this application, the concentrated dichloropropanol solution contains 80.0% dichloropropanol, 0.8% 2-chloro-1,3-propanediol, 6.4% water and 16.8% hydrogen chloride by weight.

[0076] C. Cycling reaction The concentrated dichloropropanol solution obtained from step B is sent to the mixer 9 by the dichloropropanol transfer pump 8. At the same time, the liquid alkali with a concentration of 18% by weight is also sent to the mixer 9 by the pipeline. The concentrated dichloropropanol solution and the liquid alkali are mixed evenly and then sent to the upper part of the cyclization reactor 10. The concentrated dichloropropanol solution and the liquid alkali are subjected to a cyclization reaction at a temperature of 62°C for 30 minutes. The crude epichlorohydrin obtained from the cyclization reaction is discharged from the top of the cyclization reactor 10, while the cyclization wastewater is discharged from the bottom of the cyclization reactor 10. D. Refined The crude epichlorohydrin from step C is piped to the middle of the light component removal tower 11, where light components are removed under the conditions of a tower top temperature of 64°C and a pressure of 40 kPa. The light components are discharged from the top of the light component removal tower 11, while the epichlorohydrin with the light components removed is discharged from the bottom of the light component removal tower 11 and sent by the epichlorohydrin transfer pump 12 to the middle of the product refining tower 13 for refining under the conditions of a tower top temperature of 95°C and a pressure of 50 kPa. The electronic-grade epichlorohydrin product is discharged from the top of the product refining tower 13.

[0077] According to the analytical method described in this application, the electronic-grade epichlorohydrin prepared in this embodiment contains 99.994% epichlorohydrin, 0.004% water, 0.004% dichloropropanol and 0.002% chloroacetone by weight.

Claims

1. A method for producing electronic-grade epichlorohydrin, characterized in that... The production steps of this production method are as follows: A. Chlorination reaction According to the catalyst to refined glycerol weight ratio of 1:10~20 and the refined glycerol to hydrogen chloride molar ratio of 1:2.0~2.6, refined glycerol from outside the boundary is sent to the upper part of the premix tank (1) through a pipeline, and the dicarboxylic acid catalyst is sent to the top of the premix tank (1) through a pipeline. The refined glycerol and the catalyst are stirred and mixed evenly in the premix tank (1), and then discharged from the bottom of the premix tank (1). The glycerol solution is sent to the upper part of the chlorination reactor (3) through the glycerol solution transfer pump (2) and pipeline. At the same time, hydrogen chloride gas is sent to the lower part of the chlorination reactor (3) through a pipeline. The refined glycerol and hydrogen chloride are subjected to chlorination reaction for 2~8h in the presence of the dicarboxylic acid catalyst at a temperature of 100~130℃ and a pressure of 0.1~1.0MPa. The chlorinated reaction liquid is discharged from the bottom of the chlorination reactor (3), while the unreacted hydrogen chloride gas is discharged from the top of the chlorination reactor (3) and returned to the lower part of the premix tank (1) through a pipeline. B. Dichloropropanol separation The chlorinated reaction solution obtained in step A is sent to the middle of the dichloropropanol separation tower (5) by the chlorinated liquid transfer pump (4). Separation is carried out under conditions of 100~140℃ and 8.0~14.0KPa. A dichloropropanol aqueous solution containing dichloropropanol, water, hydrogen chloride, and other organic matter is discharged from the top of the dichloropropanol separation tower (5), while a mixture of dicarboxylic acid catalyst and its ester is discharged from the bottom and returned to the chlorination reactor (3) for reuse. The dichloropropanol aqueous solution is then piped to the extraction tower (5) at a mass ratio of 1:1~10 to the extractant. 6) At the upper part, the extractant is sent from the lower part of the extraction tower (6) into the extraction tower (6), and is extracted in the extraction tower (6) at an extraction temperature of 10~40℃ for 1~4h. Then the extract phase is discharged from the top of the extraction tower (6) and the raffinate phase is discharged from the bottom of the extraction tower (6). The extract phase is sent to the middle part of the solvent recovery tower (7) through a pipeline, and is separated under the conditions of a top temperature of 60~100℃ and a pressure of 10~60KPa. The solvent and light component mixture is discharged from the top of the solvent recovery tower (7) and the concentrated dichloropropanol solution is discharged from the bottom of the solvent recovery tower (7). C. Cycling reaction The concentrated dichloropropanol solution obtained from step B is sent to the mixer (9) by the dichloropropanol transfer pump (8), and the liquid alkali is also sent to the mixer (9) by the pipeline. The concentrated dichloropropanol solution and the liquid alkali are mixed evenly and then sent to the upper part of the cyclization reactor (10). The dichloropropanol and the liquid alkali undergo a cyclization reaction at a temperature of 30~80℃ for 5~40 minutes. The crude epichlorohydrin obtained from the cyclization reaction is discharged from the top of the cyclization reactor (10), while the cyclization wastewater is discharged from the bottom of the cyclization reactor (10). D. Refined The crude epichlorohydrin from step C is piped to the middle of the light component removal tower (11), where light components are removed at a top temperature of 50-70°C and a pressure of 20-40 kPa. The light components are discharged from the top of the light component removal tower (11), while the epichlorohydrin with the light components removed is discharged from the bottom of the light component removal tower (11) and sent by the epichlorohydrin transfer pump (12) to the middle of the product refining tower (13) for refining at a top temperature of 85-95°C and a pressure of 50-60 kPa. The electronic-grade epichlorohydrin product is discharged from the top of the product refining tower (13).

2. The production method according to claim 1, characterized in that... In step A, the refined glycerol contains 99.0-99.5% glycerol, 0.01-0.05% sulfated ash, 0.5-0.8% water and 0.01-0.1% free fatty acids by weight; the dicarboxylic acid catalyst is one or more catalysts selected from oxalic acid, malonic acid, succinic acid or adipic acid.

3. The production method according to claim 1, characterized in that... In step A, the chlorination reactor (3) is a bubble column type, tubular type or circulating type reactor.

4. The production method according to claim 1, characterized in that... In step A, the chlorination reaction solution contains, by weight, 50.0–60.0% dichloropropanol, 1.0–2.0% 3-chloro-1,2-propanediol, 10.0–15.0% 2-chloro-1,3-propanediol, 0.01–0.1% glycerol, 9.0–11.0% water, and 6.0–8.0% hydrogen chloride.

5. The production method according to claim 1, characterized in that... In step B, the extractant is methyl isobutyl ketone or 1,2-dichloroethane.

6. The production method according to claim 1, characterized in that... In step B, the dichloropropanol separation tower (5) is a separation device with internal components of sieve plates, float valves, packing or bubble caps; the extraction tower (6) is an extraction device with internal components of sieve plates, packing or rotary discs; and the solvent recovery tower (7) is a recovery device with internal components of float valves, packing or sieve plates.

7. The production method according to claim 1, characterized in that... In step B, the concentrated dichloropropanol solution contains, by weight, 60.0-80.0% dichloropropanol, 0.1-1.0% 2-chloro-1,3-propanediol, 5.0-7.0% water and 15.0-20.0% hydrogen chloride.

8. The production method according to claim 1, characterized in that... In step C, the mixer (9) is a static mixer, a jet mixer, or a Venturi mixer; the cyclization reactor (10) is a plate cyclization tower reactor.

9. The production method according to claim 1, characterized in that... In step D, the light component removal tower (11) is a separation device with floating valves, packing or sieve plates as internal components; the product refining tower (13) is a separation device with floating valves, packing or sieve plates as internal components.

10. The production method according to claim 1, characterized in that... In step D, the electronic-grade epichlorohydrin contains more than 99.99% epichlorohydrin, 0.001-0.005% water, 0.001-0.005% dichloropropanol and 0.001-0.003% chloroacetone by weight.

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