A method for indoxacarb wastewater pretreatment

Abstract

The application discloses an indoxacarb wastewater pretreatment method, belongs to the technical field of indoxacarb wastewater pretreatment, and mainly aims at 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone, an intermediate of indoxacarb. First, the pH is adjusted to hydrolyze the indoxacarb intermediate into methanol and 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone derivatives with carboxylate, the methanol is collected, and then the waste liquid is adjusted to be acidic. The prepared emulsion is added, liquid-liquid separation is carried out, on the basis of recycling of the methanol and the 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone derivatives, the waste liquid meeting the national minimum emission standard is obtained, and the waste liquid is sent to a sewage treatment plant for further treatment. The indoxacarb wastewater pretreatment method has the characteristics of energy saving and consumption reduction and recycling of useful components of liquid.

Description

Technical Field

[0001] This invention belongs to the field of indoxacarb wastewater pretreatment technology, specifically relating to a method for pretreating indoxacarb wastewater. Background Technology

[0002] Indoxacarb is a typical representative of oxadiazine insecticides and the first commercially available sodium channel blocker. Its chemical name is S-7-chloro-2,5-dihydro-2-[[(methoxycarbonyl)[4-(trifluoromethoxy)-phenyl]amino]carbonyl]indo[1,2-e][1,3,4]oxadiazine-4(3H)-carboxylic acid methyl ester, and its CAS number is 144171-61-9.

[0003] Currently, existing production processes primarily synthesize the important intermediate 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone, which is then used to synthesize the final product, indoxacarb. However, during the reaction with benzyl hydrazinocarbamate, a significant amount of 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone remains. Without pretreatment, further degradation is impossible, directly impacting business operations and becoming one of the most pressing technical problems to be solved in this field.

[0004] Currently, there are few reports on pretreatment methods for indoxacarb wastewater. The main methods for pretreating toxic wastewater involve reacting and settling high concentrations of toxic wastewater through precipitation or adsorption to reduce the concentration to a treatable level. However, the reaction precipitation method may be ineffective for substances like 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone, which are difficult to precipitate. Furthermore, the reaction process may consume large amounts of reagents, and the useful components in the wastewater may be difficult to recover. For adsorption separation, the adsorbent may reach saturation after a period of use, requiring replacement or regeneration, and the regeneration effect is not always satisfactory, further increasing costs. Therefore, there is an urgent need to provide a pretreatment method for indoxacarb wastewater. Summary of the Invention

[0005] The purpose of this invention is to provide a pretreatment method for indoxacarb wastewater to solve the problems mentioned in the background art, such as the scarcity of reports on current indoxacarb wastewater pretreatment methods and the common use of reaction precipitation and adsorption separation methods, which have the problems of difficulty in forming precipitates of the substances to be treated, difficulty in recovering useful components, and high energy and material consumption.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A method for pretreatment of indoxacarb wastewater includes the following steps:

[0008] (1) In a sealed extraction and separation device, add indoxacarb wastewater; adjust the pH to 10, heat to 70-80℃, and continue the reaction for 2 hours to hydrolyze. Collect methanol by distillation at 64-66℃ for 10 minutes. Then adjust the pH to 3-4, add emulsion, and stir for 20-30 minutes at a stirring speed of 200 r / min to obtain suspension a.

[0009] (2) The suspension a is transferred into a phase separator and allowed to stand and separate into layers, separating the first lower layer solution and the first upper layer solution. The first lower layer solution is sent to the sewage treatment plant.

[0010] (3) After heating the first upper layer solution to 20–50°C for 9–23 minutes, transfer it to a phase separator and allow it to stand and separate into two layers. The second upper layer solution is a regenerated emulsion, and the second lower layer solution is a solution containing a large amount of 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone. The second upper layer solution and the second lower layer solution are collected separately for recycling.

[0011] The wastewater from the production of indoxacarb contains 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone.

[0012] The volume ratio of the indoxacarb wastewater to the emulsion is 5:1.

[0013] The pH adjusting reagent is NaOH solid and 98wt% concentrated sulfuric acid.

[0014] The preparation steps of the emulsion are as follows:

[0015] The membrane phase reagent and the internal phase reagent were added to the emulsifier, and the emulsifier was placed in a high-speed disperser for intermittent emulsification for 15 minutes to obtain an emulsion.

[0016] Furthermore, the rotational speed of the high-speed disperser is 2500–2800 r / min.

[0017] Furthermore, the volume ratio of the membrane phase reagent to the internal phase reagent is 1 to 2:1.

[0018] The internal phase reagent is a 10 wt% NaOH aqueous solution.

[0019] The membrane phase reagent comprises the following raw materials in parts by weight: 85-95 parts of household kerosene, 2-4 parts of surfactant, and 5-11 parts of liquid paraffin.

[0020] Furthermore, the surfactant is at least one of Span-80 and Tween-80.

[0021] The beneficial effects of this invention are:

[0022] This invention provides a pretreatment method for indoxacarb wastewater, employing an emulsion membrane method to separate 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone from the wastewater. After hydrolysis by adjusting the pH, a 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone derivative is generated. Due to the presence of surfactants in the membrane phase reagent, the 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone derivative diffuses into the inner phase of the emulsion, reacts with the NaOH aqueous solution in the inner phase to form the corresponding salt, and is retained in the inner phase of the emulsion, achieving highly efficient separation.

[0023] This invention provides a pretreatment method for indoxacarb wastewater that can recover a large amount of useful components. The invention achieves liquid-liquid separation using an emulsion membrane method, separating useful components without altering the properties of the substances. Furthermore, by adjusting the pH and temperature for hydrolysis, a large amount of methanol is extracted from 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone.

[0024] The indoxacarb wastewater pretreatment method provided by this invention has the characteristics of energy saving and consumption reduction. This invention achieves liquid-liquid separation through emulsion liquid membrane method, which reduces the cumbersome wastewater recycling steps and solid waste treatment steps in the existing process, and can complete effective separation in 20 to 30 minutes, reducing energy and material consumption. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] The civilian kerosene used in this invention was purchased from a civilian retail store; Span-80 was purchased from Tianjin Xiens Biochemical Technology Co., Ltd.; and the liquid paraffin, with a specification of 99%, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0027] Example 1

[0028] This embodiment provides an emulsion, which is prepared through the following steps:

[0029] A mixture of 8.5g of household kerosene, 0.2g of Span-80, and 0.5g of liquid paraffin was used as the membrane phase reagent, and a 10wt% NaOH aqueous solution was used as the internal phase reagent. 300ml of the membrane phase reagent and 300ml of the internal phase reagent were then added to an emulsifier. The emulsifier was placed in a high-speed disperser, and emulsification was carried out intermittently for 15 minutes at a speed of 2500 rpm to obtain an emulsion.

[0030] Example 2

[0031] This embodiment provides an emulsion, which is prepared through the following steps:

[0032] A mixture of 9g of household kerosene, 0.3g of Span-80, and 0.8g of liquid paraffin was used as the membrane phase reagent, and a 10wt% NaOH aqueous solution was used as the internal phase reagent. 450ml of the membrane phase reagent and 300ml of the internal phase reagent were then added to an emulsifier. The emulsifier was placed in a high-speed disperser, and emulsification was carried out intermittently for 15 minutes at a speed of 2650 rpm to obtain an emulsion.

[0033] Example 3

[0034] This embodiment provides an emulsion, which is prepared through the following steps:

[0035] A mixture of 9.5g of household kerosene, 0.4g of Span-80, and 1.1g of liquid paraffin was used as the membrane phase reagent, and a 10wt% NaOH aqueous solution was used as the internal phase reagent. 600ml of the membrane phase reagent and 300ml of the internal phase reagent were used. The membrane phase reagent and internal phase reagent were added to an emulsifier, which was then placed in a high-speed disperser. Emulsification was carried out intermittently for 15 minutes at a speed of 2800 rpm to obtain an emulsion.

[0036] Example 4

[0037] This embodiment provides a method for pretreatment of indoxacarb wastewater, including the following steps:

[0038] In a sealed extraction and separation apparatus, 1 L of indoxacarb wastewater with a concentration of 1000 mg / L was added, followed by the addition of solid NaOH to adjust the pH to 10. The mixture was heated to 70°C and allowed to continue hydrolysis for 2 hours. Subsequently, methanol was collected by distillation at 64°C for 10 minutes. Then, 98 wt% concentrated sulfuric acid was added to adjust the pH to 3, and 200 mL of the emulsion prepared in Example 1 was added. The mixture was stirred for 20 minutes at a stirring speed of 200 r / min to obtain suspension a.

[0039] Suspension a was transferred to a phase separator and allowed to settle and separate into a first lower layer and a first upper layer. The first lower layer was sent to a wastewater treatment plant. The first upper layer was heated to 20°C for 23 minutes and then transferred to a phase separator and allowed to settle and separate into a second upper layer and a second lower layer. The second upper layer was a regenerated emulsion, and the second lower layer was a solution containing a large amount of 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone. The second upper layer and the second lower layer were collected separately for recycling.

[0040] Example 5

[0041] This embodiment provides a method for pretreatment of indoxacarb wastewater, including the following steps:

[0042] In a sealed extraction and separation apparatus, 1.5 L of indoxacarb wastewater with a concentration of 1000 mg / L was added, followed by the addition of solid NaOH to adjust the pH to 10. The mixture was heated to 75°C and allowed to continue hydrolysis for 2 hours. Subsequently, methanol was collected by distillation at 65°C for 10 minutes. Then, 98 wt% concentrated sulfuric acid was added to adjust the pH to 4, and 300 mL of the emulsion prepared in Example 2 was added. The mixture was stirred for 25 minutes at a stirring speed of 200 r / min to obtain suspension a.

[0043] Suspension a was transferred to a phase separator and allowed to settle and separate into a first lower layer and a first upper layer. The first lower layer was sent to a wastewater treatment plant. The first upper layer was heated to 35°C for 16 minutes and then transferred to a phase separator and allowed to settle and separate into a second upper layer and a second lower layer. The second upper layer was a regenerated emulsion, and the second lower layer was a solution containing a large amount of 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone. The second upper layer and the second lower layer were collected separately for recycling.

[0044] Example 6

[0045] This embodiment provides a method for pretreatment of indoxacarb wastewater, including the following steps:

[0046] In a sealed extraction and separation apparatus, 2 L of indoxacarb wastewater was added, along with solid NaOH to adjust the pH to 10. The mixture was heated to 80°C and allowed to continue hydrolysis for 2 hours. Subsequently, methanol was collected by distillation at 66°C for 10 minutes. Then, 98 wt% concentrated sulfuric acid was added to adjust the pH to 4, and 400 ml of the emulsion prepared in Example 3 was added. The mixture was stirred for 30 minutes at a stirring speed of 200 r / min to obtain suspension a.

[0047] Suspension a was transferred to a phase separator and allowed to settle and separate into a first lower layer and a first upper layer. The first lower layer was sent to a wastewater treatment plant. The first upper layer was heated to 50°C for 9 minutes and then transferred to a phase separator and allowed to settle and separate into a second upper layer and a second lower layer. The second upper layer was a regenerated emulsion, and the second lower layer was a solution containing a large amount of 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone. The second upper layer and the second lower layer were collected separately for recycling.

[0048] Comparative Example 1

[0049] This embodiment provides a method for pretreatment of indoxacarb wastewater, including the following steps:

[0050] Compared with Example 4, the emulsion prepared in Example 1 of Example 4 was replaced with 10-24 mesh activated carbon, which was purchased from Aladdin Reagent (Shanghai) Co., Ltd. The other raw materials and preparation process were the same as in Example 4.

[0051] Comparative Example 2

[0052] This embodiment provides a method for pretreatment of indoxacarb wastewater, including the following steps:

[0053] Compared with Example 4, the preparation process of suspension a is as follows: In a sealed extraction and separation device, 1L of indoxacarb wastewater with a content of 1000mg / L is added, followed by the addition of 98wt% concentrated sulfuric acid to adjust the pH to 3, and then 200ml of the emulsion prepared in Example 1 is added. The mixture is stirred for 20min at a stirring speed of 200r / min to obtain suspension a. The remaining raw materials and preparation process are the same as in Example 4.

[0054] The indoxacarb wastewater pretreatment methods provided in Examples 4-6, Comparative Examples 1 and 2 were evaluated. Specifically, the wastewater requiring further treatment was evaluated according to the GB8978-1996 Integrated Wastewater Discharge Standard, and the content of 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone and its derivatives in the lower aqueous phase was detected using high-performance liquid chromatography.

[0055] HPLC conditions: Chralcel OD-H column (90.46cm×25cm), column temperature 25℃, flow rate 1mL / min, mobile phase V(n-hexane):V(isopropanol) = 90:10, detection wavelength 254nm; injection volume 20μL. Take an appropriate amount of the wastewater solution to be tested, dissolve it completely in the mobile phase to prepare a test solution with a concentration of approximately 0.1mg / mL. Inject 20μL of the test solution into the chromatograph, record the chromatogram, and calculate the residual amounts of 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone and its derivatives in the wastewater using the area normalization method. The results are shown in Table 1.

[0056] Table 1

[0057]

[0058] As shown in Table 1, the residual amounts of 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone and its derivatives in Examples 4 to 6 were all less than 0.38%, meeting the minimum standards of the National Integrated Wastewater Discharge Standard GB8978-1996. Compared to Comparative Example 1, regeneration was more convenient while still meeting the standards. Compared to Comparative Example 2, not only could methanol be recovered, but the separation amount of 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone and its derivatives was also greatly increased. This is because when 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone enters the inner phase of the emulsion, only a portion of 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone reacts with the inner phase solvent, while a large amount of 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone escapes from the inner phase.

[0059] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0060] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for pretreatment of indoxacarb wastewater, characterized in that, Includes the following steps: (1) In a sealed extraction and separation device, add indoxacarb wastewater; adjust the pH to 10, heat to 70-80℃, continue the reaction and hydrolysis for 2 hours, collect methanol by distillation at 64-66℃ for 10 minutes; then adjust the pH to 3-4, add emulsion, stir for 20-30 minutes at a stirring speed of 200 r / min to obtain suspension a; The preparation steps of the emulsion are as follows: The membrane phase reagent and the internal phase reagent were added to the emulsifier, and the emulsifier was placed in the high-speed disperser for intermittent emulsification for 15 minutes to obtain an emulsion. (2) The suspension a is transferred into a phase separator and allowed to stand and separate into layers, separating the first lower layer solution and the first upper layer solution. The first lower layer solution is sent to the sewage treatment plant. (3) After heating the first upper layer solution to 20-50℃ for 9-23 minutes, transfer it to a phase separator and let it stand to separate the layers, separating the second upper layer solution and the second lower layer solution. Collect the second upper layer solution and the second lower layer solution separately for recycling. The indoxacarb wastewater contains 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone; An emulsion membrane method was used to separate 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone from indoxacarb wastewater. After hydrolysis by adjusting the pH, a 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone derivative was generated. Due to the presence of surfactants in the membrane phase reagent, the 5-chloro-2-methoxycarbonyl-2-hydroxy-1-indanone derivative diffused into the inner phase of the emulsion, reacted with the NaOH aqueous solution in the inner phase reagent to form the corresponding salt, and was retained in the inner phase of the emulsion, thus achieving efficient separation.

2. The method for pretreatment of indoxacarb wastewater according to claim 1, characterized in that, The volume ratio of the indoxacarb wastewater to the emulsion is 5:

1.

3. The method for pretreatment of indoxacarb wastewater according to claim 1, characterized in that, The pH-adjusting reagents are solid NaOH and 98wt% concentrated sulfuric acid.

4. The method for pretreatment of indoxacarb wastewater according to claim 1, characterized in that, The high-speed disperser rotates at a speed of 2500–2800 r / min.

5. The method for pretreatment of indoxacarb wastewater according to claim 1, characterized in that, The volume ratio of the membrane phase reagent to the internal phase reagent is 1 to 2:

1.

6. The method for pretreatment of indoxacarb wastewater according to claim 1, characterized in that, The internal phase reagent is a 10 wt% NaOH aqueous solution.

7. The method for pretreatment of indoxacarb wastewater according to claim 1, characterized in that, The membrane phase reagent comprises the following raw materials in parts by weight: 85-95 parts of household kerosene, 2-4 parts of surfactant, and 5-11 parts of liquid paraffin.

8. The method for pretreatment of indoxacarb wastewater according to claim 7, characterized in that, The surfactant is at least one of Span-80 and Tween-80.

Images