A method for pretreating cumene oxidation liquid and application thereof

Abstract

This invention discloses a pretreatment method for cumene oxidation liquid and its application. The method includes alkaline washing of the cumene oxidation liquid containing cumene hydroperoxide with an alkaline washing agent, followed by oil-water phase separation treatment, and finally passing the resulting oil phase through a hydrophobic filter material. Compared with oxidation liquids containing high concentrations of acid and sodium ions, the oxidation liquid treated by this invention can significantly improve the activity and stability of the epoxidation catalyst when used as a raw material for epoxidation reactions. Furthermore, compared with existing deacidification and sodium removal processes, this method eliminates the need for multi-stage water washing, hydrocyclone separation, and other enhanced separation methods, making the process simpler.

Description

Technical Field

[0001] This invention relates to the field of olefin epoxide production technology, and more specifically, to a pretreatment method for cumene oxide solution used in olefin epoxidation and its application. Background Technology

[0002] Propylene oxide, also known as 1,2-epoxypropane, is mainly used in the production of derivative chemicals such as polyether polyols, polyurethanes, propylene glycol, propylene glycol ethers, and propylene carbonate. Its applications cover almost all industrial sectors and daily life scenarios, and it is the second largest propylene-based product after polypropylene.

[0003] There are multiple routes available for propylene oxide production technology. The CHPPO process, which uses cumene hydroperoxide as an oxidant, has advantages such as no byproducts and is safe and environmentally friendly, and has a promising future. The CHPPO process mainly includes: cumene oxidation to generate cumene hydroperoxide (CHP); CHP then reacts with propylene as an oxidant to produce propylene oxide (PO) and dimethyl benzyl alcohol (DMBA). The products are separated and purified to obtain PO; the remaining DMBA is hydrogenated to generate cumene for recycling.

[0004] The oxidation of cumene to CHP is a relatively mature technology. However, most industrial cumene oxidation processes are currently used for phenol and acetone production, where the acidic components in the oxidation products are not a major concern. In the CHPPO process, a cumene oxidation solution containing approximately 30 wt% to 60 wt% CHP is typically used as a raw material. Under current technology, this oxidation solution often contains 100 to 1000 ppm of organic acids, including formic acid, acetic acid, propionic acid, and benzoic acid. These organic acids have significant adverse effects on subsequent epoxidation reactions, potentially leading to decreased catalyst activity and increased byproducts. Therefore, deacidification of the cumene oxidation solution is a necessary step in olefin epoxidation applications.

[0005] In existing technologies, strong alkaline solutions such as sodium hydroxide and sodium carbonate are typically used to neutralize and remove acid from cumene oxidation solutions. However, for oxidation solutions, especially those with high CHP concentrations, severe emulsification often occurs during alkaline washing, making oil-water phase separation difficult. This often necessitates the design of large settling tanks, resulting in high equipment investment and operating costs.

[0006] Furthermore, the oxidizing solution after alkaline washing contains a high content of sodium ions. When this oxidizing solution is used in the epoxidation reaction, it may cause blockage of the catalyst bed. Current technology requires that the sodium content in the cumene oxidizing solution used in the epoxidation reaction not exceed 1.0 mg / kg. To meet this requirement, the oxidizing solution often needs to be repeatedly washed with water after alkaline washing to completely remove sodium ions. This operation further increases equipment and operating costs and generates more saline wastewater.

[0007] To address the aforementioned issues, some patents have proposed enhancing phase separation during the alkaline washing (water washing) process. Patent CN111892523A discloses a method for separating, removing acid and sodium in a CHPPO unit. This method involves setting up a "mixer-centrifuge-oil-water separator," with the centrifuge oil phase containing a small amount of water and the centrifuge water phase containing no oil. This process removes acid and sodium from the impurity-laden oxidizing liquid, resulting in a purified oxidizing liquid with organic acid impurities ≤50 mg / kg and sodium ion impurities ≤1.0 mg / kg. This purified oxidizing liquid can be applied to the industrial production of CHPPO units.

[0008] Patent CN111892522A discloses a method for separating, removing acid and sodium using a CHPPO device. This method employs a combined process of a stirrer and an aggregator, incorporating an advanced impeller structure within the stirrer and three layers of special materials within the aggregator. This process purifies an oxidizing solution containing 100-5000 mg / kg of organic acid and 20-800 mg / kg of sodium ions. The organic acid removal rate is 59.30-99.00%, and the sodium ion removal rate is 95.45-99.88%, yielding a purified oxidizing solution with organic acid ≤50 mg / kg and sodium ion ≤1.0 mg / kg.

[0009] Similarly, patents CN111848325A and CN111807920A disclose a method for deacidifying cumene raw materials using a "mixer-cyclone separator-oil-water separator-mixer-aggregator" to obtain cumene with organic acid ≤50mg / kg. However, simply deacidifying the cumene raw materials is insufficient to ensure that the organic acid in the cumene oxidation solution is also completely removed, and some organic acid will still be generated during the oxidation process.

[0010] Existing technologies for optimizing the acid and sodium removal steps of cumene oxidation liquid mainly rely on devices such as centrifuges to enhance the phase separation process. However, the process remains relatively cumbersome, and the reduction in equipment investment and operating costs is limited. Summary of the Invention

[0011] To optimize existing processes for removing acid and alkali from cumene oxidation solutions and improve the performance indicators of the CHP-based olefin epoxidation reaction at a lower cost, this invention proposes a pretreatment method for cumene oxidation solutions, particularly for epoxidation technologies using cumene hydroperoxide as the oxidant.

[0012] One objective of this invention is to provide a pretreatment method for cumene oxide solution, comprising using an alkaline washing agent to perform alkaline washing on the cumene oxide solution containing hydrogen peroxide, followed by oil-water phase separation treatment, and finally passing the resulting oil phase through a hydrophobic filter material.

[0013] In the pretreatment method of the present invention, the concentration of cumene hydroperoxide in the cumene oxidation solution does not exceed 30 wt%, preferably 10-20 wt%. Alternatively, for cumene oxidation solutions with a cumene hydroperoxide concentration exceeding 30 wt%, the cumene oxidation solution with a cumene hydroperoxide concentration exceeding 30 wt% is diluted with a diluent to a concentration not exceeding 30 wt%, wherein the diluent is preferably at least one selected from cumene, ethylbenzene, toluene, and p-xylene.

[0014] In the pretreatment method of the present invention, the alkaline washing agent is selected from the conjugate base corresponding to a weak base with a pKb range of 4 to 8, a weak acid with a pKa range of 6 to 10, or a mixture thereof.

[0015] The weak base is preferably selected from at least one of ammonium hydroxide, hydrazine, and hydroxylamine, and the conjugate base is preferably selected from at least one of sodium bicarbonate and sodium hydrogen phosphate; preferably, the alkaline detergent is sodium bicarbonate or a mixture of sodium bicarbonate and the weak base, wherein there is no particular limitation on the ratio of sodium bicarbonate to the weak base.

[0016] In the pretreatment method described in this invention, a stronger but cheaper detergent, such as sodium carbonate, can be added during the alkaline washing treatment. The molar amount of the stronger alkaline agent, such as sodium carbonate, does not significantly exceed the total molar amount of organic acids in the oxidation solution; it is lower than or approximately equal to the total molar amount of organic acids in the oxidation solution, i.e., it does not exceed 10 times the total molar amount of organic acids.

[0017] In the pretreatment method of the present invention, the molar amount of the alkaline washing agent is 1 to 1000 times the total molar amount of organic acids in the cumene oxidation solution, preferably 10 to 100 times.

[0018] In the pretreatment method of the present invention, the hydrophobic filter material is selected from at least one of membrane, fabric, porous material, and solid particle bed, and is preferably a hydrophobic microporous membrane, wherein the pore size of the hydrophobic microporous membrane is preferably 0.2 to 2.0 μm.

[0019] In the pretreatment method of the present invention, the oil-water phase treatment is carried out by gravity sedimentation or centrifugation.

[0020] In the pretreatment method described in this invention, the cumene oxidized liquid obtained after the pretreatment method can be concentrated to reach the required specified concentration.

[0021] The second objective of this invention is to provide the cumene oxide solution obtained by the aforementioned pretreatment method.

[0022] In the cumene oxidation liquid, the organic acid content is converted into benzoic acid content (mg / kg), and the organic acid content calculated as benzoic acid is less than 20mg / kg, and the sodium ion content is less than 1mg / kg.

[0023] A third objective of this invention is to provide the application of the pretreatment method in the production of olefin epoxides.

[0024] The pretreatment method of this invention involves using a strictly defined alkaline washing agent to perform alkaline washing on an oxidation solution with a specified CHP concentration. After alkaline washing, the oil phase stream is filtered through a hydrophobic filter material to remove the emulsion phase, and then concentrated to the specified concentration required for the downstream epoxidation reaction.

[0025] The cumene oxidation liquid processed by the method of this invention can be used as a raw material in the olefin epoxidation process, mainly for propylene epoxidation, but it can also be extended to systems where olefins such as butene, butadiene, and cyclohexene are oxidized by CHP.

[0026] The main advantage of this invention is that it prevents emulsification during alkaline washing of cumene oxide solution, resulting in clear stratification of the oil and water phases after treatment. The oil and water phases can be separated using simple separation methods. At the same time, it can effectively reduce the content of organic acid impurities such as formic acid, acetic acid and benzoic acid in CHP, and minimize the content of sodium ions and other impurities carried over due to alkaline washing.

[0027] Beneficial effects of the invention:

[0028] This invention is mainly aimed at cumene oxide solution containing hydrogen peroxide (CHP) used in olefin epoxidation processes such as CHPPO units. The purpose is to solve the problem of severe emulsification during alkaline washing of cumene oxide solution in the prior art, which causes difficulty in separating the oil and water phases.

[0029] Compared with some existing processes for deacidifying and removing sodium from cumene oxide liquid, the pretreatment method for cumene oxide liquid proposed in this invention avoids emulsification during alkaline washing, eliminates the need for multi-stage water washing, hydrocyclone separation and other enhanced separation methods, and simplifies the process and reduces costs. Detailed Implementation

[0030] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0031] The pretreatment method for cumene oxidation liquid of the present invention selects an alkaline component with a strictly limited pKb value within a certain range as an alkaline washing agent. Alkaline washing treatment is performed on cumene oxidation liquid with a CHP concentration of no more than 30%, which can effectively reduce components such as organic acids, sodium ions and water entrained in the organic phase. After alkaline washing, the oil phase is passed through a hydrophobic filter material to remove a small amount of emulsion phase, and then concentrated to a specified concentration to obtain cumene oxidation liquid with an organic acid content of less than 20 mg / kg and a sodium ion content of less than 1 mg / kg.

[0032] According to a preferred embodiment of the present invention, the pretreatment method requires strict limitation on the type of alkaline washing agent used for alkaline washing of the oxidizing solution. The main limiting condition is the strength of the alkali, measured by the pKb value (ionization equilibrium constant of the alkali). Preferably, weak bases with a pKb range of 4 to 8 are used, including conjugate bases of weak acids, i.e., conjugate bases corresponding to acids with pKa values ​​(ionization equilibrium constants of acids) ranging from 6 to 10, as well as mixtures of weak bases and conjugate bases of weak acids.

[0033] The base with the specified strength can be an inorganic base, such as, but not limited to, ammonium hydroxide, hydrazine, hydroxylamine, etc.; it can be a conjugate base of a weak acid, such as, but not limited to, sodium bicarbonate, sodium hydrogen phosphate, etc.; the preferred option is to choose a conjugate base such as a sodium salt, and the more preferred option is sodium bicarbonate or a mixture mainly composed of sodium bicarbonate, such as a mixture of sodium bicarbonate and a weak base, and there is no particular limitation on the ratio of sodium bicarbonate to the weak base.

[0034] According to a preferred embodiment of the present invention, the concentration and amount of alkaline washing agent are typically determined based on the content of organic acids in the cumene oxidation solution to be treated. Calculated according to acid-base neutralization equivalents, the amount of alkali used should significantly exceed the amount of organic acids in the oxidation solution. Preferably, the molar ratio of alkali to acid (i.e., the molar amount of alkaline washing agent to the total molar amount of organic acids in the cumene oxidation solution) is 1 to 1000 times, more preferably in the range of 10 to 100 times, for example, 1, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 500, 800, 1000, etc. If the acid content in the cumene oxidation solution to be treated is too high, a large amount of alkali is required, and the water-to-oil ratio is too disproportionate during alkaline washing. In such cases, stepwise alkaline washing is permitted for ease of operation.

[0035] According to a preferred embodiment of the present invention, the concentration of CHP in the oxidizing solution during alkaline washing is generally not higher than 30 wt%, preferably 10-20 wt%, and it is permissible to dilute the cumene oxidizing solution from a high concentration of more than 30 wt% to the preferred concentration range using cumene or similar aromatic and alkane solvents such as ethylbenzene.

[0036] According to a preferred embodiment of the present invention, after alkali washing, oil-water phase separation can be performed using simple gravity sedimentation, but some enhanced phase separation measures such as hydrocyclone separation are also permissible. The separated aqueous phase can be reused after appropriate replenishment of alkali.

[0037] According to a preferred embodiment of the present invention, the oil phase separated after alkali washing, i.e., the oxidized liquid, is further filtered through a hydrophobic filter material to cut off the W / O type emulsion phase entrained therein. The selected filter material includes, but is not limited to, membranes, fabrics, porous materials, solid particle beds, etc., preferably hydrophobic microporous membrane materials, and more preferably hydrophobic microporous membrane materials with pore sizes in the range of 0.1 to 2.0 μm.

[0038] According to a preferred embodiment of the present invention, depending on the actual scenario of subsequent use of the oxidizing liquid, the concentration of CHP in the treated oxidizing liquid can be increased by evaporating the cumene solvent. The evaporated cumene can then be used as a solvent to dilute the excessively concentrated oxidizing liquid, as described above.

[0039] According to a preferred embodiment of the present invention, the above pretreatment typically yields an isopropylbenzene oxidation solution with an organic acid (calculated as benzoic acid) content of less than 20 mg / kg and a sodium ion content of less than 1 mg / kg. The specific calculation method is as follows: determine the total molar amount of organic acid in 1 kg of isopropylbenzene oxidation solution based on the results of acid-base titration, and then convert it to the mass of an equivalent molar amount of benzoic acid.

[0040] The present invention will be further described below through specific embodiments. The specific parameters of the embodiments do not limit the scope of the claims made by the present invention.

[0041] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0042] The following embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

[0043]

Example 1

[0044] 200 mL of cumene was poured into a three-necked flask equipped with a condenser and stirrer. A small amount of CHP was added to initiate the reaction. Air was bubbled into the liquid at a rate of 100 mL / min, and the mixture was heated to 110 °C while stirring. The reaction was continued for 12 hours to obtain an oxidized solution with a CHP concentration of approximately 21 wt% (confirmed by iodometric titration). The solution was then diluted to 15 wt% with cumene. The organic acid content was confirmed to be 279 mg / kg by titration (the organic acid content was converted to benzoic acid content).

[0045] Take 100g of oxidizing solution diluted to 15wt%. Prepare a 5wt% sodium bicarbonate aqueous solution as the alkaline washing solution. Mix 10g of sodium bicarbonate solution with the oxidizing solution, stir and shake for 10min, and let stand. Within 30min, the oil and water phases will clearly separate into two phases. Take out the oil phase separated after alkaline washing and filter it on a glass frit filter equipped with a 0.22μm PTFE microporous membrane.

[0046] The filtered oxidizing solution was titrated to confirm that the acid content had decreased to 12.1 mg / kg, and the sodium ion content was analyzed to be 0.28 mg / kg by atomic spectroscopy.

[0047]

Example 2

[0048] The operation steps are the same as in Example 1, except that a small amount of benzoic acid is added to the oxidation solution to adjust the organic acid content to 500 mg / kg.

[0049] Increasing the organic acid content in the oxidation solution, the experimental phenomena during alkaline washing and filtration were not significantly different from those in Example 1. During alkaline washing, the oil and water phases were clearly separated, and no emulsification occurred.

[0050] After alkaline washing and filtration, the acid content in the oxidation solution is 12.9 mg / kg, and the sodium ion content is 0.39 mg / kg.

[0051]

Example 3

[0052] An oxidizing solution containing organic acids was prepared according to the operating steps in Example 1. The alkaline washing solution used was a mixed solution containing 4.8 wt% sodium bicarbonate and 0.2 wt% sodium carbonate. 10 g of the alkaline washing solution was mixed with 100 g of the oxidizing solution diluted to 15 wt%. Alkaline washing and filtration were performed according to the same steps as in Example 1. The experimental phenomena observed were not significantly different from those in Example 1. During alkaline washing, the oil and water phases clearly separated, and no emulsification occurred.

[0053] After alkaline washing and filtration, the acid content in the oxidation solution is 11.5 mg / kg, and the sodium ion content is 0.91 mg / kg.

[0054]

Example 4

[0055] Following the operating steps in Example 1, the alkaline washing solution used was an aqueous solution containing 5 wt% sodium hydrogen phosphate (Na2HPO4). For 100 g of oxidizing solution diluted to 15 wt%, 10 g of the alkaline washing solution was mixed with the oxidizing solution, and alkaline washing and filtration were performed according to the same steps as in Example 1. The experimental phenomena observed during the operation were not significantly different from those in Example 1; during alkaline washing, the oil and water phases clearly separated, and no emulsification occurred.

[0056] After alkaline washing and filtration, the acid content in the oxidation solution was 18.9 mg / kg, and the sodium ion content was 0.87 mg / kg.

[0057]

Example 5

[0058] Following the operating steps in Example 1, the alkaline washing solution used was an aqueous solution containing 5 wt% ammonium hydroxide. For 100 g of oxidizing solution diluted to 15 wt%, 10 g of alkaline washing solution was mixed with the oxidizing solution, and alkaline washing and filtration were performed according to the same steps as in Example 1. The experimental phenomena observed during the operation were not significantly different from those in Example 1; during alkaline washing, the oil and water phases clearly separated, and no emulsification occurred.

[0059] After alkaline washing and filtration, the acid content in the oxidation solution was 17.1 mg / kg. Since no sodium-containing alkaline washing agent was used, the sodium content was not detected (<0.1 mg / kg).

[0060]

Example 6

[0061] Following the operating steps in Example 1, the alkaline washing solution used was an aqueous solution containing 4 wt% sodium bicarbonate and 1 wt% ammonium hydroxide. For 100 g of oxidizing solution diluted to 15 wt%, 10 g of the alkaline washing solution was mixed with the oxidizing solution, and alkaline washing and filtration were performed according to the same steps as in Example 1. The experimental phenomena observed during the operation were not significantly different from those in Example 1; during alkaline washing, the oil and water phases clearly separated, and no emulsification occurred.

[0062] After alkaline washing and filtration, the acid content in the oxidation solution is 12.5 mg / kg, and the sodium ion content is 0.60 mg / kg.

[0063] Comparative Example 1

[0064] The operation steps are the same as in Example 1, except that after alkaline washing, the mixture is kept still for 12 hours, and the upper oil phase is taken out without stirring the interface and without filtration.

[0065] In the oxidizing solution that is washed with alkali but not filtered, the acid content is 9.5 mg / kg and the sodium ion content is 5.1 mg / kg.

[0066] Comparative Example 2

[0067] The procedure was the same as in Example 1, except that a 5 wt% sodium hydroxide solution was used as the alkaline washing solution. Significant emulsification occurred during alkaline washing, making it difficult for the oil and water phases to separate. After 24 hours of settling, the oil phase remained slightly turbid. The separated oil phase was then filtered using a vacuum filtration device equipped with a 0.22 μm PTFE microporous membrane.

[0068] The oxidizing solution, after being washed with sodium hydroxide and filtered, contained 0.8 mg / kg of acid and 21.9 mg / kg of sodium ions.

[0069] Comparative Example 3

[0070] The procedure was the same as in Example 1, except that the alkaline washing solution was an aqueous solution containing 2.5 wt% sodium carbonate and 2.5 wt% sodium bicarbonate. 10 g of the alkaline washing solution was mixed with 100 g of oxidizing solution diluted to 15 wt%. The amount of sodium carbonate (2.36 mmol), which is highly alkaline, was significantly higher than the organic acid content in the oxidizing solution (approximately 0.23 mmol). A noticeable emulsification phenomenon occurred during the alkaline washing. After standing for 24 hours, the oil phase was separated and filtered through a 0.22 μm PTFE microporous membrane.

[0071] After alkali washing and filtration with a mixture of sodium carbonate and sodium bicarbonate, the acid content in the oxidizing solution was 16.9 mg / kg and the sodium ion content was 24.7 mg / kg.

[0072]

Example 7

[0073] The deacidified cumene oxidation liquids from Examples 1-6 were used as raw materials for evaluation experiments on the propylene epoxidation reaction. The evaluation experiments used a Ti-HMS catalyst, and the catalyst method disclosed in Example 2 of patent publication number CN104437636A was referenced. The specific reaction conditions were as follows: 1.0 g of catalyst was loaded into a fixed-bed reactor; the cumene oxidation liquid was fed at a rate of 0.2 mL / min and mixed with liquid propylene at a rate of 0.3 mL / min before being passed through the catalyst for reaction. The reaction temperature was maintained at 90°C, and the reaction pressure was maintained at 3.2 MPaG.

[0074] After removing propylene from the reaction outlet product under reduced pressure, the remaining CHP content was determined by iodometric titration, and the CHP conversion rate was calculated using the following formula:

[0075] Conversion rate = 100% × (residual CHP content in product ÷ CHP content in raw material).

[0076] A higher conversion rate indicates better catalyst activity.

[0077] Comparative Example 4

[0078] An evaluation experiment on the propylene epoxidation reaction was conducted using cumene oxidized liquid before acid removal as raw material, following the method described in Example 7.

[0079] Comparative Example 5

[0080] The cumene oxide solution treated in Comparative Example 2 was used as raw material, and an evaluation experiment of the propylene epoxidation reaction was carried out according to the method in Example 7.

[0081] Comparative Example 6

[0082] The cumene oxide solution treated in Comparative Example 3 was used as raw material, and an evaluation experiment of the propylene epoxidation reaction was carried out according to the method in Example 7.

[0083] The conversion rates of cumene oxide solutions treated by different methods for propylene epoxidation are compared in Table 1 below:

[0084] Table 1 Comparison of various cumene oxidation solutions used in epoxidation reactions

[0085]

[0086] The results show that using the deacidified cumene oxidation solution in the epoxidation reaction is beneficial to improving the activity of the epoxidation catalyst. In Comparative Examples 5 and 6, although the sodium ion content was high, complete deacidification still had a positive effect on the reaction conversion rate. However, the high sodium ion content of the oxidation solution can easily cause problems such as catalyst bed blockage during long-term operation.

[0087] The results show that this invention can produce an isopropylbenzene oxidation liquid with an organic acid content of less than 20 mg / kg (based on benzoic acid) and a sodium ion content of less than 1 mg / kg. Compared with oxidation liquids containing high concentrations of acid and sodium ions, the treated oxidation liquid can significantly improve the activity and stability of the epoxidation catalyst when used as a raw material for the epoxidation reaction.

Claims

1. A pretreatment method for cumene oxide solution, comprising: alkali washing the cumene oxide solution containing cumene peroxide with an alkaline washing agent; followed by oil-water phase separation treatment; and finally passing the resulting oil phase through a hydrophobic filter material; wherein the alkaline washing agent is selected from pK b It is a weak base with a strength of 4-8 and a pK value of 8. a The conjugate base or a mixture thereof is a weak acid of 6 to 10, wherein the weak base is selected from at least one of ammonium hydroxide, hydrazine, and hydroxylamine, and the conjugate base is selected from at least one of sodium bicarbonate and sodium hydrogen phosphate. The molar amount of the alkaline washing agent is 10 to 100 times the total molar amount of organic acids in the cumene oxidation solution, and the hydrophobic filter material is a hydrophobic microporous membrane.

2. The pretreatment method for cumene oxidation liquid according to claim 1, characterized in that: The concentration of cumene hydroperoxide in the cumene oxidation solution does not exceed 30 wt%. Alternatively, the cumene oxide solution with a concentration exceeding 30 wt% hydrogen peroxide can be diluted with a diluent to a concentration not exceeding 30 wt%.

3. The pretreatment method for cumene oxidation liquid according to claim 2, characterized in that: The concentration of cumene hydroperoxide in the cumene oxidation solution is 10-20 wt%. The diluent is selected from at least one of cumene, ethylbenzene, toluene, and p-xylene.

4. The pretreatment method for cumene oxidation liquid according to claim 1, characterized in that: The alkaline detergent is sodium bicarbonate, or a mixture of sodium bicarbonate and a weak alkali.

5. The pretreatment method for cumene oxidation liquid according to claim 1, characterized in that: The hydrophobic microporous membrane has a pore size of 0.2~2.0 μm.

6. The pretreatment method for cumene oxidation liquid according to claim 1, characterized in that: The oil-water phase separation process employs gravity sedimentation or centrifugation.

7. The pretreatment method for cumene oxidation liquid according to claim 1, characterized in that: The cumene oxidized solution obtained after pretreatment was concentrated.

8. The application of the pretreatment method according to any one of claims 1 to 7 in the production of olefin epoxides.

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