A method for separating residual peroxides in an epoxy soybean oil

Abstract

This invention provides a method for separating residual peroxides from epoxidized soybean oil. The method involves using a superheated, low-boiling-point stripping agent to react with the peroxide-containing epoxidized soybean oil solution in a stripping tower for gas-liquid mass transfer. During this process, the peroxides in the epoxidized soybean oil are rapidly vaporized and separated. The vaporized peroxide-containing vapor is within a safe combustion range and is further separated after condensation, allowing for the recycling of the peroxides. This method not only efficiently removes residual peroxides from epoxidized soybean oil but also ensures that the epoxy value of the obtained epoxidized soybean oil remains essentially unchanged (the difference is less than 0.02).

Description

Technical Field

[0001] This invention belongs to the field of peroxide separation technology; specifically, it relates to a method for separating residual peroxides in epoxidized soybean oil, particularly a method for separating residual tert-butyl hydrogen peroxide in epoxidized soybean oil. Background Technology

[0002] Epoxidized soybean oil is a chemical product obtained by oxidizing soybean oil. It is a light yellow, viscous, oily liquid at room temperature. It can be used as a plasticizer and stabilizer for polyvinyl chloride (PVC). It has good compatibility with PVC resin, low volatility, and low migration. It has excellent thermal and light stability, as well as good water and oil resistance. It can give products good mechanical strength, weather resistance, and electrical properties. It is also non-toxic and is currently an internationally recognized chemical process aid for food packaging materials.

[0003] The preparation process of epoxidized soybean oil typically involves using hydrogen peroxide as the oxygen source, formic acid as the oxygen carrier, and sulfuric acid as the catalyst. These are mixed with soybean oil to undergo an epoxidation reaction. After the reaction, the mixture is washed with water and dried to obtain the final product. However, this process suffers from problems such as long reaction time and the generation of large amounts of acidic wastewater.

[0004] Alkyl organic peroxides are excellent oxidants for soybean oil epoxidation, offering advantages such as no acidic wastewater generation and rapid reaction rates. Existing technologies have reported the use of tert-butyl hydroperoxide (TBHP) solution as an oxygen source to oxidize fatty acid esters and soybean oil under catalysis. After the reaction, the remaining TBHP and byproduct tert-butanol (TBA) are separated by vacuum distillation. Further processes such as washing and drying then yield high-quality finished epoxidized fatty acid esters and epoxidized soybean oil. However, due to the high boiling point of TBHP, the vacuum distillation temperature typically needs to be maintained above 100°C for a prolonged period to separate TBHP from the epoxidized product, which can easily lead to a darker product color and a decrease in epoxy value. Furthermore, TBHP is prone to decomposition at high temperatures, and prolonged high-temperature vacuum distillation can cause TBHP decomposition, posing a safety risk to the production process.

[0005] Existing technologies have also reported methods for removing residual TBHP from epoxidized soybean oil using tert-butanol steam stripping. Although this method can safely and quickly remove TBHP from epoxidized soybean oil, the epoxy value of the epoxidized soybean oil will decrease to some extent during the stripping process, which cannot guarantee the performance of the epoxidized soybean oil. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, this invention provides a method for separating residual peroxides in epoxidized soybean oil, particularly a method for separating residual tert-butyl hydrogen peroxide in epoxidized soybean oil. The separation method is characterized by safe and stable operation. It can remove residual peroxides (especially tert-butyl hydrogen peroxide) from epoxidized soybean oil within a short time (e.g., within 30 minutes), thus preparing high-quality epoxidized soybean oil (i.e., epoxidized soybean oil with high epoxy value and low peroxide content).

[0007] The objective of this invention is achieved through the following technical solution: A method for separating residual peroxides in epoxidized soybean oil, the method comprising the following steps: 1) The epoxidized soybean oil reaction solution containing peroxide is preheated by a preheater and then sent to the top of the stripping tower; 2) The stripping agent is sequentially fed into the vaporizer for vaporization, then into the superheater for superheating, and finally fed into the bottom of the stripping tower in the form of steam. 3) The stripping agent in step 2) and the peroxide-containing epoxidized soybean oil reaction solution in step 1) undergo gas-liquid mass transfer in the stripping tower. The peroxide-containing steam is collected at the top of the stripping tower, and the finished epoxidized soybean oil is collected at the bottom of the stripping tower.

[0008] According to an embodiment of the present invention, in step 1), the source of the peroxide-containing epoxidized soybean oil reaction solution is not particularly limited, and it can be an epoxidized soybean oil reaction solution containing peroxide obtained by methods known in the art; for example, it can be an epoxidized soybean oil reaction solution containing peroxide prepared by epoxidation reaction using tert-butyl hydroperoxide as an oxidant.

[0009] According to an embodiment of the present invention, in step 1), the epoxidized soybean oil reaction solution containing peroxide includes epoxidized soybean oil, peroxide, and solvent; the peroxide is selected from tert-butyl hydroperoxide; and the solvent is selected from tert-butanol.

[0010] According to an embodiment of the present invention, in step 1), the mass percentage of peroxide in the epoxidized soybean oil reaction solution containing peroxide is 0-15 wt%, preferably 5-13 wt%, for example, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, or 15 wt%. If the mass percentage of peroxide in the epoxidized soybean oil reaction solution containing peroxide is >15 wt%, the epoxidized soybean oil reaction solution containing peroxide can be flash-evaporated first (exemplarily, the flash-evaporation temperature is 110-120℃ (e.g., 114℃), and the flash-evaporation pressure is -0.03~-0.08 MPa (e.g., -0.051 MPa)) to remove most of the peroxide in the epoxidized soybean oil reaction solution containing peroxide, thereby improving the removal efficiency of the method of the present application for residual peroxide in the epoxidized soybean oil reaction solution containing peroxide.

[0011] According to an embodiment of the present invention, in step 1), the mass percentage of solvent in the peroxide-containing epoxidized soybean oil reaction solution is 0-12 wt%, preferably 5-12 wt%, for example 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, or 12 wt%.

[0012] According to an embodiment of the present invention, in step 1), the mass percentage of solvent in the peroxide-containing epoxidized soybean oil reaction solution is lower than the mass percentage of peroxide in the peroxide-containing epoxidized soybean oil reaction solution.

[0013] According to an embodiment of the present invention, in step 1), the preheater is a device known in the art capable of preheating materials.

[0014] According to an embodiment of the present invention, in step 1), the preheating temperature is 90-115℃, preferably 95-110℃, for example 90℃, 95℃, 100℃, 105℃, 110℃ or 115℃; the preheating time is not specifically defined, as long as it can ensure that the temperature of the peroxide-containing epoxidized soybean oil reaction solution after preheating reaches the preheating temperature; in the present invention, the preheating temperature refers to the temperature of the peroxide-containing epoxidized soybean oil reaction solution after preheating by the preheater.

[0015] According to an embodiment of the present invention, in step 2), the stripping agent comprises substituted or unsubstituted alkanes, substituted or unsubstituted cycloalkanes; if substituted, the substituent is an alkyl or chlorine atom; preferably, the stripping agent comprises substituted or unsubstituted C 1-12Alkanes, substituted or unsubstituted C 3-12 Cycloalkanes; if substituted, the substituent is C. 1-12 Alkyl or chlorine atom; and more preferably, the stripping agent comprises substituted or unsubstituted C atoms. 1-6 Alkanes, substituted or unsubstituted C 3-8 Cycloalkanes; if substituted, the substituent is C. 1-6 Alkyl or chlorine atom; more preferably, the stripping agent comprises substituted or unsubstituted C atoms. 1-6 Alkanes, substituted or unsubstituted C 3-6 Cycloalkanes; if substituted, the substituent is C. 1-6 Alkyl or chlorine atom; exemplarily, the stripping agent includes at least one of isobutane, n-hexane, cyclohexane, dichloromethane, and dichloroethane, preferably n-hexane and dichloromethane.

[0016] According to an embodiment of the present invention, in step 2), the stripping agent further includes a solvent, wherein the solvent is selected from tert-butanol.

[0017] According to an embodiment of the present invention, in step 2), the mass ratio of substituted or unsubstituted alkanes and substituted or unsubstituted cycloalkanes to solvent in the stripping agent is 99:1-85:15, for example, 99:1, 98:2, 97:3, 96:4, 95:5, 94:6, 93:7, 92:8, 91:9, 90:10, 89:11, 88:12, 87:13, 86:14, or 85:15. The addition of solvent can reduce the amount of substituted or unsubstituted alkanes and substituted or unsubstituted cycloalkanes used in the stripping agent, thereby reducing costs.

[0018] According to an embodiment of the present invention, in step 2), the vaporizer is a device known in the art capable of vaporizing the stripping agent.

[0019] According to an embodiment of the present invention, in step 2), the vaporization temperature is 80-120°C, preferably 90-110°C, for example, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, or 120°C. The vaporization time is not specifically defined, as long as it is sufficient to vaporize the stripping agent into a gas. In this invention, the vaporization temperature refers to the temperature reached by the stripping agent after vaporization in the vaporizer.

[0020] According to an embodiment of the present invention, in step 2), the superheater is a device known in the art capable of superheating steam.

[0021] According to an embodiment of the present invention, in step 2), the superheating temperature is 90-130℃, preferably 100-120℃, for example, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, or 130℃. The superheating time is not specifically defined; it only needs to raise the temperature of the stripping agent in vapor form after vaporization. In this invention, the superheating temperature refers to the temperature of the stripping agent in vapor form after superheating treatment in the superheater. Research has found that by increasing the temperature of the stripping agent fed to the bottom of the stripping tower, the removal efficiency of residual peroxides in the epoxidized soybean oil reaction solution containing peroxides is improved, resulting in a low peroxide content while ensuring that the epoxidized soybean oil has a high epoxy value.

[0022] According to an embodiment of the present invention, in step 2), the superheating temperature is 5°C higher than the vaporization temperature, preferably 5-20°C higher, such as 5°C, 10°C, 15°C, or 20°C. Studies have found that by increasing the temperature of the stripping agent fed into the bottom of the stripping tower, the removal efficiency of residual peroxides in the epoxidized soybean oil reaction solution containing peroxides can be improved, achieving a low peroxide content while ensuring that the epoxidized soybean oil has a high epoxy value. In particular, when the mass percentage of residual peroxides in the epoxidized soybean oil reaction solution containing peroxides is high, the removal efficiency of residual peroxides in the epoxidized soybean oil reaction solution containing peroxides can be improved by appropriately increasing the temperature of the stripping agent fed into the bottom of the stripping tower.

[0023] According to an embodiment of the present invention, in step 3), the mass ratio of the flow rate of the stripping agent fed to the bottom of the stripping tower to the flow rate of the peroxide-containing epoxidized soybean oil reaction solution fed to the top of the stripping tower is 40-90%, for example, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or 90%. When the mass ratio of the flow rate of the stripping agent fed to the bottom of the stripping tower to the flow rate of the peroxide-containing epoxidized soybean oil reaction solution fed to the top of the stripping tower is 40-90%, efficient removal of residual peroxides in the peroxide-containing epoxidized soybean oil reaction solution can be achieved, while also reducing the cost of the separation process and saving energy. When the mass percentage of residual peroxides in the peroxide-containing epoxidized soybean oil reaction solution is high, the flow rate of the stripping agent fed to the bottom of the stripping tower can also be appropriately increased, thereby achieving efficient removal of residual peroxides in the peroxide-containing epoxidized soybean oil reaction solution.

[0024] According to an embodiment of the present invention, in step 3), the stripping tower includes a first inlet, a second inlet, and a first outlet; wherein, the first inlet of the stripping tower is connected to the outlet of the preheater of the peroxide-containing epoxidized soybean oil reaction liquid, and the first inlet is located at the top of the stripping tower for introducing the peroxide-containing epoxidized soybean oil reaction liquid into the stripping tower; the second inlet of the stripping tower is connected to the outlet of the superheater, and the second inlet is located at the bottom of the stripping tower for introducing the superheated stripping agent into the stripping tower; the first outlet of the stripping tower is connected to the epoxidized soybean oil storage tank, and the first outlet is located at the bottom of the stripping tower for exporting the crude epoxidized soybean oil after the peroxide separation.

[0025] According to an embodiment of the present invention, in step 3), the stripping tower further includes a second outlet for discharging vapor containing peroxide (e.g., vapor containing peroxide, solvent and stripping agent), and the second outlet is located at the top of the stripping tower.

[0026] According to an embodiment of the present invention, in step 3), steam containing peroxide, solvent and stripping agent is extracted from the top of the stripping tower.

[0027] According to an embodiment of the present invention, in step 3), the stripping tower is a stripping tower conventionally used in the art; exemplaryly, the theoretical number of stages of the stripping tower is 5-20, preferably 7-15.

[0028] According to an embodiment of the present invention, in step 3), the operating pressure in the stripping tower is 5-25 kPa; preferably, the operating pressure in the stripping tower is 10-15 kPa.

[0029] According to an embodiment of the present invention, in step 3), the temperature of the bottom of the stripping tower is 60-100°C; preferably, the temperature of the bottom of the stripping tower is 60-90°C.

[0030] According to an embodiment of the present invention, in step 3), the top temperature of the stripping tower is 60-90°C; preferably, the top temperature of the stripping tower is 60-80°C.

[0031] According to an embodiment of the present invention, the method further includes the following steps: 4) The peroxide-containing steam extracted from the top of the stripping tower is condensed and liquefied by a condenser and sent to the steam condensate recovery tank; optionally, the peroxide in the steam condensate recovery tank is separated and reused.

[0032] According to an embodiment of the present invention, in step 4), the temperature of the condensation and liquefaction is -10~20℃, preferably 0~10℃.

[0033] According to an embodiment of the present invention, the method further includes the following steps: 5) The epoxidized soybean oil, after the peroxides have been removed from the bottom of the stripping tower, is extracted by the extraction pump and sent to the epoxidized soybean oil storage tank.

[0034] According to an embodiment of the present invention, in step 5), the mass percentage of peroxide in the epoxidized soybean oil obtained after stripping is less than or equal to 0.5 wt%, preferably less than or equal to 0.3 wt%, for example 0-0.2 wt%.

[0035] According to an embodiment of the present invention, in step 5), the difference between the epoxy value of the epoxidized soybean oil obtained after stripping and the epoxy value of the epoxidized soybean oil in the peroxide-containing epoxidized soybean oil reaction solution is less than 0.02, for example, 0-0.01.

[0036] Beneficial effects: This invention provides a method for separating residual peroxides in epoxidized soybean oil, specifically a method for separating residual tert-butyl hydrogen peroxide. The invention utilizes a superheated, low-boiling-point stripping agent to conduct gas-liquid exchange mass transfer with the peroxide-containing epoxidized soybean oil reaction solution within a stripping tower. During this process, the peroxides in the epoxidized soybean oil are rapidly vaporized and separated. The vaporized peroxide-containing vapor is within a safe combustion range, and further separation and processing after condensation allows for the recycling of the peroxides. This method not only efficiently removes residual peroxides from epoxidized soybean oil but also ensures that the epoxy value of the obtained epoxidized soybean oil remains essentially unchanged (difference less than 0.02), meaning that high-quality epoxidized soybean oil products can be obtained using this method. Compared with existing technologies, the present invention uses substituted or unsubstituted alkanes or substituted or unsubstituted cycloalkanes as stripping agents to separate residual peroxides in epoxidized soybean oil. This method is characterized by safe operation, high peroxide recovery rate, and high epoxy value of the product. It is a new, green, environmentally friendly, economical and efficient epoxidized soybean oil production process. Attached Figure Description

[0037] Figure 1 The above is a process flow diagram of the method for separating residual peroxides in epoxidized soybean oil, which is a preferred embodiment of the present invention.

[0038] The attached diagram shows the following labels: 1-Crude epoxidized soybean oil tank, 2-Preheater, 3-Stripping agent tank, 4-Vaporizer, 5-Superheater, 6-Stripping tower, 7-Condenser, 8-Condensate receiving tank, 9-Tower bottom transfer pump, 10-Epoxidized soybean oil storage tank. Detailed Implementation

[0039] The method of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0040] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0041] The crude epoxidized soybean oil used in the following examples and comparative examples includes epoxidized soybean oil (BM), tert-butyl hydroperoxide (TBHP), and tert-butanol (TBA), wherein the concentration of TBHP is 11.27 wt%, the concentration of TBA is 8.87 wt%, and the iodine value of BM is 3.37 and the epoxy value is 6.39.

[0042] In this invention, unless otherwise specified, the term "concentration" refers to "mass concentration", that is, "mass percentage content".

[0043] Example 1 The crude epoxidized soybean oil was pumped to a preheater at a flow rate of 18.0 kg / hr and preheated to 97.5°C before being fed to the top of the stripping tower. Hexane from the solvent tank was pumped to a vaporizer at a flow rate of 12.6 kg / hr, vaporized, and then heated to 100°C before being fed to the bottom of the stripping tower. The top pressure of the stripping tower was maintained at 10 kPa, the top temperature at 66.2°C, and the vapor flow rate from the top was 15.9 kg / hr. This vapor was condensed to 0°C in a condenser and entered the top collection tank. The composition of the top vapor condensate was: 67.77% hexane, 12.72% TBHP, 17.37% TBA, with the remainder being impurities.

[0044] The temperature of the stripping tower bottom is 78.0℃. The epoxidized soybean oil in the tower bottom is pumped to the product tank at a flow rate of 14.7 kg / hr. The composition of the bottom product is as follows: TBHP concentration is 0.2%, TBA concentration is 0.42%, n-hexane concentration is 3.92%, BM concentration is 95.01%, and BM epoxy value is 6.39.

[0045] Example 2 The crude epoxidized soybean oil was pumped to a preheater at a flow rate of 18.0 kg / hr and preheated to 97.5°C before being fed to the top of the stripping tower. Dichloromethane in the solvent tank was pumped to a vaporizer at a flow rate of 15.4 kg / hr, vaporized, and then heated to 100°C before being fed to the bottom of the stripping tower. The top pressure of the stripping tower was maintained at 10 kPa, the top temperature at 63.5°C, and the vapor flow rate from the top was 19.0 kg / hr. This vapor was condensed to 0°C in a condenser and entered the top collection tank. The composition of the top vapor condensate was: 8.4% TBA, 10.67% TBHP, 79.13% dichloromethane, with the remainder being impurities.

[0046] The temperature of the stripping tower bottom is 64.7℃. Epoxidized soybean oil in the bottom is pumped to the product tank at a flow rate of 14.4 kg / hr via the bottom discharge pump. The composition of the bottom product is as follows: TBHP concentration is 0.21%, TBA concentration is 0.30%, dichloromethane concentration is 2.54%, BM concentration is 96.81%, and the epoxy value of BM is 6.39.

[0047] Example 3 The crude epoxidized soybean oil was pumped to a preheater at a flow rate of 18.0 kg / hr and preheated to 98°C before being fed to the top of the stripping tower. A cyclohexane-tert-butanol mixed solvent (mass ratio 89:11) in the solvent tank was pumped to a vaporizer at a flow rate of 12.65 kg / hr for vaporization. The vapor was then heated to 100°C by a heat exchanger and fed to the bottom of the stripping tower. The top pressure of the stripping tower was maintained at 10 kPa, the top temperature at 66.3°C, and the vapor flow rate from the top was 15.96 kg / hr. This vapor was condensed to 10°C in a condenser and entered the top collection tank. The composition of the top vapor condensate was: 67.04% cyclohexane, 12.71% TBHP, 18.12% TBA, with the remainder being impurities.

[0048] The temperature of the stripping tower bottom is 78.0℃. Epoxidized soybean oil in the bottom is pumped to the product tank at a flow rate of 14.69 kg / hr via the bottom discharge pump. The composition of the bottom product is as follows: TBA concentration is 0.67%, TBHP concentration is 0.19%, cyclohexane concentration is 3.80%, BM concentration is 95.09%, and the epoxy value of BM is 6.38.

[0049] Comparative Example 1 The crude epoxidized soybean oil was pumped to a preheater at a flow rate of 18.0 kg / hr and preheated to 97.5°C before being fed to the top of the stripping tower. TBA in the solvent tank was pumped to a vaporizer at a flow rate of 8.8 kg / hr for vaporization. The vapor was then heated to 100°C by a heat exchanger and fed to the bottom of the stripping tower. The top pressure of the stripping tower was maintained at 10 kPa, the top temperature at 71.3°C, and the vapor flow rate from the top was 11.8 kg / hr. This vapor was condensed to 10°C in a condenser and entered the top collection tank. The composition of the top vapor condensate was: 17.26% TBHP, 79.61% TBA, and the remainder being impurities.

[0050] The temperature of the stripping tower bottom is 78.0℃. The epoxidized soybean oil in the bottom is pumped to the product tank at a flow rate of 15.0 kg / hr. The composition of the bottom product is: TBHP concentration of 0.22%, TBA concentration of 6.57%, BM concentration of 92.88%, and BM epoxy value of 6.29.

[0051] As can be seen from the above examples and comparative examples, the separation method of the present invention can effectively remove residual peroxides (especially tert-butyl hydrogen peroxide) from epoxidized soybean oil, and prepare high-quality epoxidized soybean oil (i.e., epoxidized soybean oil with high epoxy value and low peroxide content).

[0052] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for separating residual peroxides in epoxidized soybean oil, the separation method comprising the following steps: 1) The epoxidized soybean oil reaction solution containing peroxide is preheated by a preheater and then sent to the top of the stripping tower; 2) The stripping agent is sequentially fed into the vaporizer for vaporization, then into the superheater for superheating, and finally fed into the bottom of the stripping tower in the form of steam. 3) The stripping agent in step 2) and the peroxide-containing epoxidized soybean oil reaction solution in step 1) undergo gas-liquid mass transfer in the stripping tower. The peroxide-containing steam is collected at the top of the stripping tower, and the finished epoxidized soybean oil is collected at the bottom of the stripping tower.

2. The separation method according to claim 1, wherein, In step 1), the epoxidized soybean oil reaction solution containing peroxide includes epoxidized soybean oil, peroxide, and solvent; the peroxide is selected from tert-butyl hydroperoxide; the solvent is selected from tert-butanol. And / or, in step 1), the mass percentage of peroxide in the epoxidized soybean oil reaction solution containing peroxide is 0-15 wt%, preferably 5-13 wt%; And / or, in step 1), the mass percentage of the solvent in the peroxide-containing epoxidized soybean oil reaction solution is 0-12 wt%, preferably 5-12 wt%. Preferably, in step 1), the mass percentage of solvent in the peroxide-containing epoxidized soybean oil reaction solution is lower than the mass percentage of peroxide in the peroxide-containing epoxidized soybean oil reaction solution. Preferably, in step 1), the preheating temperature is 90-115°C.

3. The separation method according to claim 1 or 2, wherein, In step 2), the stripping agent includes substituted or unsubstituted alkanes and substituted or unsubstituted cycloalkanes; if substituted, the substituent is an alkyl or chlorine atom; Preferably, the stripping agent comprises substituted or unsubstituted C 1-12 Alkanes, substituted or unsubstituted C 3-12 Cycloalkanes; if substituted, the substituent is C. 1-12 Alkyl or chlorine atom; Preferably, the stripping agent comprises substituted or unsubstituted C 1-6 Alkanes, substituted or unsubstituted C 3-8 Cycloalkanes; if substituted, the substituent is C. 1-6 Alkyl or chlorine atom; Preferably, the stripping agent comprises substituted or unsubstituted C 1-6 Alkanes, substituted or unsubstituted C 3-6 Cycloalkanes; if substituted, the substituent is C. 1-6 Alkyl or chlorine atom; Preferably, the stripping agent includes at least one of isobutane, n-hexane, cyclohexane, dichloromethane, and dichloroethane, with n-hexane and dichloromethane being more preferred.

4. The separation method according to any one of claims 1-3, wherein, In step 2), the stripping agent further includes a solvent, which is selected from tert-butanol. Preferably, in step 2), the mass ratio of substituted or unsubstituted alkanes, substituted or unsubstituted cycloalkanes to solvent in the stripping agent is 99:1-85:

15.

5. The separation method according to any one of claims 1-4, wherein, In step 2), the vaporization temperature is 80-120℃; And / or, in step 2), the overheating temperature is 90-130°C; And / or, in step 2), the overheating temperature is more than 5°C higher than the vaporization temperature.

6. The separation method according to any one of claims 1-5, wherein, In step 3), the mass ratio of the flow rate of the stripping agent fed to the bottom of the stripping tower to the flow rate of the peroxide-containing epoxidized soybean oil reaction liquid fed to the top of the stripping tower is 40-90%.

7. The separation method according to any one of claims 1-6, wherein, In step 3), the stripping tower includes a first inlet, a second inlet, and a first outlet; wherein, the first inlet of the stripping tower is connected to the outlet of the preheater of the peroxide-containing epoxidized soybean oil reaction liquid, and the first inlet is located at the top of the stripping tower for introducing the peroxide-containing epoxidized soybean oil reaction liquid into the stripping tower; the second inlet of the stripping tower is connected to the outlet of the superheater, and the second inlet is located at the bottom of the stripping tower for introducing the superheated stripping agent into the stripping tower; the first outlet of the stripping tower is connected to the epoxidized soybean oil storage tank, and the first outlet is located at the bottom of the stripping tower for exporting the crude epoxidized soybean oil after the peroxide separation. Preferably, in step 3), the stripping tower further includes a second outlet for discharging vapor containing peroxides (e.g., vapor containing peroxides, solvents, and stripping agents), and the second outlet is located at the top of the stripping tower.

8. The separation method according to any one of claims 1-7, wherein, In step 3), the theoretical number of stages in the stripping tower is 5-20. And / or, in step 3), the operating pressure in the stripping tower is 5-25 kPa; And / or, in step 3), the temperature of the bottom of the stripping tower is 60-100℃; And / or, in step 3), the temperature at the top of the stripping tower is 60-90°C.

9. The separation method according to any one of claims 1-8, wherein, The method further includes the following steps: 4) The peroxide-containing steam extracted from the top of the stripping tower is condensed and liquefied by a condenser and sent to the steam condensate recovery tank; optionally, the peroxide in the steam condensate recovery tank is separated and reused. Preferably, in step 4), the temperature of the condensation and liquefaction is -10~20℃.

10. The separation method according to any one of claims 1-9, wherein, The method further includes the following steps: 5) The epoxidized soybean oil, after the peroxides have been removed from the bottom of the stripping tower, is extracted by the extraction pump and sent to the epoxidized soybean oil storage tank. Preferably, in step 5), the peroxide content in the epoxidized soybean oil obtained after stripping is less than or equal to 0.5 wt%. Preferably, in step 5), the difference between the epoxy value of the epoxidized soybean oil obtained after stripping and the epoxy value of the epoxidized soybean oil in the peroxide-containing epoxidized soybean oil reaction solution is less than 0.02.

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