A treatment method for the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one

Abstract

The present invention relates to the technical field of industrial wastewater treatment, and specifically discloses a method for treating the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one. First, the production wastewater is adsorbed by a styrene-type macroporous adsorption resin with a specific pore size to separate and recover the 2-azabicyclo[2.2.1]hept-5-en-3-one product rich in the production wastewater; the adsorption liquid is oxidized to convert the macromolecular organic matters rich in the production wastewater into small-molecular organic matters; after the oxidation liquid is acidified, a weak-base acrylic-type anion exchange resin with a specific pore size is used to adsorb and separate various small-molecular organic matters in the acidified liquid to obtain a purified liquid; the purified liquid is adjusted to weak alkalinity and then concentrated and dried, and an alcohol solvent is added to separate methyl sulfonic acid from sodium chloride and sodium sulfate, and the mixed salts can separate sodium chloride and sodium sulfate by nanofiltration.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial wastewater treatment, and particularly relates to a method for treating the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one. Background Art

[0002] The main downstream products of 2-azabicyclo[2.2.1]hept-5-en-3-one are the drugs abacavir and peramivir. Abacavir is a new generation of anti-HIV drug developed by GlaxoSmithKline, belonging to a new generation of reverse transcriptase inhibitors, and has characteristics such as high oral bioavailability and slow drug resistance. Peramivir is a new type of neuraminidase inhibitor against influenza virus, developed by the American company Biocryst, and has played a key role in combating the H1N1 influenza virus. As an intermediate for these two drugs, 2-azabicyclo[2.2.1]hept-5-en-3-one is a very important compound, and its uses have been more widely expanded at home and abroad.

[0003] During the production process of 2-azabicyclo[2.2.1]hept-5-en-3-one products, a large amount of organic high-salt wastewater will be generated. In addition to containing 2-azabicyclo[2.2.1]hept-5-en-3-one products, this wastewater also contains organic components such as high-concentration methylsulfinic acid, dichloromethane, and polycyclic compounds formed by polymerization, and the COD concentration is as high as about 80,000 mg / L. Moreover, a variety of raw materials such as sodium bicarbonate and sodium sulfite are used in its synthesis process, which inevitably leads to the existence of a variety of mixed salts in its production wastewater. Coupled with the high salt content, it is difficult to completely solve the problem of effective treatment of 2-azabicyclo[2.2.1]hept-5-en-3-one production wastewater by using the current single physical, chemical, or biological methods.

[0004] In the prior art, a method for treating chemical wastewater containing nitrogen heterocyclic compounds by combining flocculation precipitation, electrolytic oxidation, and biochemical treatment has been reported. This process is complex and the treatment cost is high, and it is not suitable for the treatment of high-concentration wastewater. There are also literatures mentioning the use of a two-step catalytic oxidation technology to treat nitrogen heterocyclic pesticide wastewater. Although it can achieve efficient removal of organic matter, the heterogeneous metal catalyst involved in its treatment process is not easy to recycle, and the wastewater needs to be adjusted to acidic and operated under high temperature and high pressure conditions. This not only requires relatively harsh equipment materials, but also has potential safety hazards and high treatment costs, and it is difficult to implement industrially. Therefore, there is an urgent need for a method that can effectively treat the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one. Summary of the Invention

[0005] In view of the problems that the existing wastewater from the production of 2-azabicyclo[2.2.1]hept-5-en-3-one contains a large amount of organic matter and inorganic mixed salts, is difficult to treat, has high treatment costs, and is difficult to implement industrially, the present invention provides a method for treating wastewater from the production of 2-azabicyclo[2.2.1]hept-5-en-3-one. It mainly separates and recovers various effective components in the wastewater from the production of 2-azabicyclo[2.2.1]hept-5-en-3-one one by one through specific steps such as resin adsorption, oxidation, acidification, alcohol precipitation, and nanofiltration, and at the same time separates the various mixed salts rich in the wastewater, completely solving the technical problem that the wastewater from the production of 2-azabicyclo[2.2.1]hept-5-en-3-one is difficult to treat, and having high economic and environmental benefits.

[0006] To solve the above technical problems, the technical solution provided by the present invention is:

[0007] A method for treating wastewater from the production of 2-azabicyclo[2.2.1]hept-5-en-3-one, comprising the following steps:

[0008] Step a, introducing the wastewater from the production of 2-azabicyclo[2.2.1]hept-5-en-3-one into a non-polar styrene-based macroporous adsorption resin for adsorption to obtain an adsorption solution;

[0009] Step b, introducing oxygen into the adsorption solution and performing oxidation at 250°C to 270°C to obtain an oxidation solution;

[0010] Step c, adjusting the pH of the oxidation solution to strong acidity to obtain an acidified solution; introducing the acidified solution into a macroporous weakly basic acrylic-based anion exchange resin for adsorption to obtain a purified solution;

[0011] Step d, adjusting the pH of the purified solution to weak alkalinity, concentrating and drying to obtain a crude product; adding an alcohol solvent to the crude product, adjusting the pH to strong acidity, and performing solid-liquid separation to obtain a separation solution and mixed salts;

[0012] Step e, performing desolvation on the separation solution to obtain methanesulfonic acid;

[0013] Among them, the pore diameter of the non-polar styrene-based macroporous adsorption resin is The pore diameter of the macroporous weakly basic acrylic-based anion exchange resin is 0.40 mm to 0.70 mm.

[0014] Compared with the prior art, the method for treating the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one provided by the present invention first adsorbs the production wastewater with a styrene-type macroporous adsorption resin with a specific pore size to separate and recover the 2-azabicyclo[2.2.1]hept-5-en-3-one product rich in the production wastewater; then, the adsorption liquid is oxidized with oxygen as an oxidant under specific conditions to convert the macromolecular organic substances rich in the production wastewater into small-molecular organic substances (such as formic acid and acetic acid substances); then the oxidation liquid is acidified to convert all the sodium carbonate and sodium bicarbonate rich in the oxidation liquid into sodium chloride, and then a weakly basic acrylic acid-based anion exchange resin with a specific pore size is used to adsorb and separate various small-molecular organic substances in the acidified liquid to obtain a purified liquid; then the purified liquid is adjusted to a weakly basic state and then concentrated and dried, and an alcohol solvent is added to separate methyl sulfonic acid from sodium chloride and sodium sulfate to obtain an alcohol separation liquid rich in methyl sulfonic acid and a mixed salt rich in sodium sulfate and sodium chloride. After the separation liquid is desolvated, methyl sulfonic acid with a purity of more than 98% can be obtained. The mixed salt can separate sodium chloride and sodium sulfate by nanofiltration to obtain sodium chloride and sodium sulfate with a purity of more than 98% respectively.

[0015] The whole treatment process of the present invention is simple, safe and controllable. It can separate and recover various effective substances in the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one one by one, avoid the loss and waste of effective components, realize the harmless treatment and resource utilization of industrial wastewater, and at the same time, the added value generated by the recovered by-products can greatly reduce the treatment cost of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one, effectively solve the problem of treating the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one, and has high economic and environmental benefits and high practical value.

[0016] It should be noted that the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one in the present invention is the production wastewater obtained by a synthesis reaction process using dichloromethane as a solvent and methylsulfonyl chloride, sodium sulfite, sodium bicarbonate, cyclopentadiene and cyanogen chloride as raw materials. The pH of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one is 6-7, the concentration of COD therein is 60000mg / L-80000mg / L, the TOC concentration is 25000mg / L-35000mg / L, the mass concentration of 2-azabicyclo[2.2.1]hept-5-en-3-one is 0.5%-0.6%, the mass concentration of NaCl is 9%-11%, the mass concentration of Na2SO4 is 2%-3%, the mass concentration of sodium methyl sulfinate is 2%-3%, and the mass concentration of total salt is 19%-21%.

[0017] Preferably, in step a, the specific surface area of the non-polar styrene-based macroporous adsorption resin is 650 m 2 / g to 750 m 2 / g.

[0018] Preferably, in step a, the non-polar styrene-based macroporous adsorption resin is Diaion HP 20.

[0019] The preferred non-polar styrene-based macroporous adsorption resin has an appropriate pore size for adsorbing 2-azabicyclo[2.2.1]hept-5-en-3-one. Using it to treat the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one can effectively adsorb and separate the 2-azabicyclo[2.2.1]hept-5-en-3-one product rich in the wastewater, and will not adsorb other polycyclic compounds. While effectively reducing the COD and TOC concentrations of the wastewater, it can also effectively ensure the purity of the separated 2-azabicyclo[2.2.1]hept-5-en-3-one product.

[0020] Preferably, in step a, the adsorption flow rate is 0.6 BV / h to 0.8 BV / h.

[0021] It should be noted that when the adsorption volume of the non-polar styrene-based macroporous adsorption resin reaches 35 BV to 40 BV, it is desorbed and analyzed with dichloromethane, and the desorbed non-polar styrene-based macroporous adsorption resin can be recycled.

[0022] Furthermore, in step a, the adsorbed non-polar styrene-based macroporous adsorption resin is analyzed with dichloromethane, and the analysis solution is desolvated and dried to obtain the 2-azabicyclo[2.2.1]hept-5-en-3-one product.

[0023] The adsorbed non-polar styrene-based macroporous adsorption resin is desorbed and analyzed with dichloromethane. After desolvating the analysis solution, a 2-azabicyclo[2.2.1]hept-5-en-3-one product with a purity greater than 98% can be obtained. The dichloromethane solvent obtained by desolvation can be recycled as the analysis agent for the next batch of resin, or can be recycled as the reaction solvent for synthesizing the 2-azabicyclo[2.2.1]hept-5-en-3-one product.

[0024] The recovered 2-azabicyclo[2.2.1]hept-5-en-3-one product with a purity greater than 98% can be recycled to the purification process of 2-azabicyclo[2.2.1]hept-5-en-3-one to further improve its purity, obtaining a 2-azabicyclo[2.2.1]hept-5-en-3-one product with a purity greater than 99.5%, and reducing the production cost of the 2-azabicyclo[2.2.1]hept-5-en-3-one product.

[0025] Further, in step a, the adsorption temperature is 25°C to 30°C.

[0026] By limiting the above adsorption temperature, the precipitation of impurities in the wastewater can be avoided, the resin adsorption system can be prevented from being blocked, the adsorption effect of the wastewater can be ensured, and the deterioration of 2-azabicyclo[2.2.1]hept-5-en-3-one caused by too high temperature can also be avoided, further ensuring the quality of the recovered 2-azabicyclo[2.2.1]hept-5-en-3-one.

[0027] Preferably, in step b, the oxidation time is 6h to 7h.

[0028] By limiting the oxidation at 250°C to 270°C, the refractory macromolecular organic compounds in the 2-azabicyclo[2.2.1]hept-5-en-3-one production wastewater can be completely degraded, and they can be completely converted into small molecular organic compounds such as formic acid and acetic acid; at the same time, under the condition that sodium methylsulfinate is not decomposed, sodium methylsulfinate can be completely oxidized to sodium methylsulfonate, providing a basis for the subsequent separation and recovery of methyl sulfonic acid.

[0029] The preferred oxidation time further ensures the degradation rate of the refractory macromolecular organic compounds in the nitrogen heteropolycyclic class.

[0030] Preferably, in step b, the mass of oxygen introduced is 0.05 to 0.10 times the mass of the adsorption liquid.

[0031] As a specific embodiment of the present invention, in step b, the oxidation reaction is carried out in a closed container. First, the 2-azabicyclo[2.2.1]hept-5-en-3-one production wastewater is added to the closed container, 0.05 to 0.10 times the amount of oxygen is introduced, the oxygen is closed, and the temperature is raised to 250°C to 270°C, and the oxidation reaction is carried out while maintaining the temperature.

[0032] The inventor found in the experiment that strong oxidants such as hydrogen peroxide or sodium persulfate cannot fully degrade the macromolecular organic compounds in the 2-azabicyclo[2.2.1]hept-5-en-3-one production wastewater. In addition, hydrogen peroxide is easy to decompose and the storage conditions are relatively harsh, and sodium persulfate is easy to introduce additional inorganic salts into the system, increasing the burden on the treatment system.

[0033] Using oxygen as the oxidant raw material for the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one is more environmentally friendly, does not introduce other impurities into the wastewater additionally, and under specific oxidation conditions, can promote the rapid chain breaking of large molecular organic compounds of azapolycyclic classes to generate small molecular organic compounds such as formic acid and acetic acid, ensuring the degradation rate of large molecular organic compounds of azapolycyclic classes, and controlling the degradation rate of large molecular organic compounds of azapolycyclic classes above 90%, creating a prerequisite for the subsequent treatment of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one.

[0034] Preferably, in step c, the strong acidity refers to a pH value of 1 to 2.

[0035] Exemplarily, in step c, before resin adsorption, the pH of the oxidation liquid is adjusted to strong acidity.

[0036] Adjusting the pH of the oxidation liquid to 1 to 2 before resin adsorption can convert all carbonates and bicarbonates in the wastewater into chlorides, avoiding the influence of the common ion effect on the solubility of bicarbonates, resulting in the precipitation of bicarbonates clogging the resin adsorption system and affecting the adsorption effect of the resin system.

[0037] Preferably, in step c, the macroporous weakly basic acrylic anion exchange resin is D311.

[0038] Preferably, in step c, the adsorption flow rate is 1.3 BV / h to 1.5 BV / h.

[0039] Preferably, in step c, the adsorption temperature is 15°C to 25°C.

[0040] The oxidation liquid after high-temperature oxidation is rich in certain concentrations of small molecular organic compounds such as formic acid and acetic acid. By adsorbing through a specific adsorption resin at a specific flow rate and temperature, the COD concentration of the purified liquid after adsorption can be controlled within 1000 mg / L, ensuring the quality of the purified liquid.

[0041] Preferably, in step d, the weak alkalinity refers to a pH value of 7 to 8.

[0042] Exemplarily, in step d, the pH of the purified liquid is adjusted to 7 to 8 using liquid caustic soda with a mass concentration of 32%. Within this pH range, the corrosion of equipment during the subsequent high-temperature drying process can be reduced.

[0043] Preferably, in step d, the concentration and drying are carried out by spray drying.

[0044] Furthermore, in step d, the temperature of spray drying is 110°C to 130°C, and the water content of the crude product obtained by spray drying is 0.6% to 1.0%.

[0045] By adopting the spray drying method, the drying efficiency can be improved, and the quality of sodium methyl sulfonate, sodium chloride and sodium sulfate obtained in the subsequent separation can be ensured.

[0046] Preferably, in step d, the alcohol solvent is methanol or ethanol.

[0047] Preferably, in step d, the addition amount of the alcohol solvent is 1.5 - 2.0 times the mass of the crude product.

[0048] Preferably, in step d, the strong acidity means that the pH value is 1 - 2.

[0049] Preferably, in step d, the temperature of the solid-liquid separation is 5°C - 15°C.

[0050] By adding a specific amount of methanol or ethanol to the crude product, controlling the specific pH and the temperature of solid-liquid separation, methyl sulfonic acid can be fully separated from sodium chloride and sodium sulfate, while ensuring the full precipitation of sodium chloride and sodium sulfate, and improving the recovery rates of methyl sulfonic acid, sodium chloride and sodium sulfate.

[0051] As a specific embodiment of the present invention, in step d, after adding the alcohol solvent, stir at 5°C - 15°C for 1h - 2h and then perform solid-liquid separation.

[0052] Preferably, in step e, the separation liquid is desolvated by means of atmospheric distillation, and when the top temperature of the distillation column reaches 110°C - 130°C, stop distillation.

[0053] By limiting the temperature at the end point of desolvation, the solvent in the separation liquid can be fully recovered, while ensuring the quality of the recovered methyl sulfonic acid, so that the purity of the recovered methyl sulfonic acid reaches more than 98%.

[0054] Preferably, it further includes step f: subjecting the mixed salt to nanofiltration to obtain sodium chloride and sodium sulfate.

[0055] In the present invention, existing conventional nanofiltration methods can be adopted. The mixed salt is dissolved in water for nanofiltration and dehydration to obtain sodium chloride and sodium sulfate. Any existing mature nanofiltration method can be used. The present invention does not make special limitations. As long as the conventional nanofiltration method in the art is adopted, the mixed salt can be separated to obtain sodium chloride and sodium sulfate with a purity of more than 98%.

[0056] The production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one provided by the present invention has simple process operation and strong controllability. It can recover various effective substances in the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one one by one, and at the same time separate various mixed salts rich in the wastewater, obtaining 2-azabicyclo[2.2.1]hept-5-en-3-one, methanesulfonic acid, sodium chloride and sodium sulfate with a purity greater than 98%. It not only effectively solves the problem of difficult treatment of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one, but also realizes the comprehensive treatment and resource utilization of the wastewater. It has strong industrial feasibility, high economic and environmental benefits, and extremely high promotion value. Detailed implementation manners

[0057] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0058] To better illustrate the present invention, further illustrative examples are given below through embodiments.

[0059] The production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one used in the following examples and comparative examples is the production wastewater obtained by a synthesis reaction process using dichloromethane as a solvent and methanesulfonyl chloride, sodium sulfite, sodium bicarbonate, cyclopentadiene, cyanogen chloride, etc. as raw materials.

[0060] In the following examples, the Diaion HP 20 macroporous adsorption resin is produced by Mitsubishi; the D311 macroporous adsorption resin is produced by Shanghai Hualing; the HYA-108 is produced by Xi'an Hanyu; the D318 macroporous adsorption resin is produced by Shanghai Hualing.

[0061] Example 1

[0062] This example provides a method for treating the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one. Among them, the pH of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one is 6.72, the concentration of COD is 80000 mg / L, the TOC concentration is 35000 mg / L, the mass concentration of 2-azabicyclo[2.2.1]hept-5-en-3-one is 0.6%, the mass concentration of NaCl is 9.96%, the mass concentration of Na2SO4 is 2.86%, the mass concentration of sodium methylsulfinate is 2.69%, and the mass concentration of total salts is 19.81%.

[0063] The treatment method includes the following steps:

[0064] Step 1: At 25°C, 5000 g of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one was introduced into Diaion HP20 non-polar styrene-based macroporous adsorption resin for adsorption at an adsorption flow rate of 0.7 BV / h. When the resin adsorption volume reached 35 BV, the resin system adsorption reached saturation, and 4960 g of adsorption liquid was obtained;

[0065] The resin adsorption system was desorbed with dichloromethane, and after desolvation of the desorbed liquid, 29.4 g of 2-azabicyclo[2.2.1]hept-5-en-3-one with a purity of 98.4% was obtained;

[0066] Step 2: 4960 g of the adsorption liquid was added to a closed reaction kettle, 248 g of oxygen was introduced, and the temperature was raised to 250°C for oxidation for 6.0 h to obtain 5020 g of oxidation liquid. The COD concentration of the oxidation liquid was detected to be 8000 mg / L;

[0067] Step 3: The pH of 5020 g of the oxidation liquid was adjusted to 1.0 with 216 g of a hydrochloric acid solution with a mass concentration of 30% to obtain 5158 g of acidified liquid;

[0068] Step 4: At 15°C, 5158 g of the obtained acidified liquid was introduced into D311 macroporous weakly basic acrylic-based anion exchange resin for adsorption to obtain 4963 g of purified liquid. The COD concentration of the purified liquid was detected to be 2100 mg / L, and the TOC concentration was 665 ppm;

[0069] Step 5: The pH of 4963 g of the purified liquid was adjusted to 7.0 with 177 g of a liquid caustic soda with a mass concentration of 32%, and then spray drying was carried out at 110°C to obtain 872 g of crude product. The water content of the crude product was detected to be 1.0%;

[0070] Step 6: 1308 g of methanol was added to 872 g of the crude product, and then the pH was adjusted to 1.0 with hydrochloric acid with a mass concentration of 30%. Stirring was carried out at 5°C for 2.0 h, and filtration was carried out to obtain 1424 g of separated liquid and 754 g of mixed salts;

[0071] Step 7: The 1424 g of separated liquid was subjected to atmospheric distillation, and distillation was stopped when the top temperature of the distillation column reached 110°C to obtain 116 g of methanesulfonic acid with a purity of 98.36%;

[0072] Step 8: The obtained 754 g of mixed salts was dissolved in water, subjected to nanofiltration and dehydration to obtain 565 g of sodium chloride with a purity of 98.6% and 142 g of sodium sulfate with a purity of 98.2%.

[0073] Example 2

[0074] This embodiment provides a method for treating the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one. Among them, the pH of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one is 6.65, the concentration of COD is 60000 mg / L, the concentration of TOC is 25000 mg / L, the mass concentration of 2-azabicyclo[2.2.1]hept-5-en-3-one is 0.5%, the mass concentration of NaCl is 9.02%, the mass concentration of Na2SO4 is 2.10%, the mass concentration of sodium methylsulfinate is 2.04%, and the mass concentration of total salts is 19.01%.

[0075] The treatment method includes the following steps:

[0076] Step 1: At 30 °C, 5000 g of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one is introduced into Diaion HP20 non-polar styrene-based macroporous adsorption resin for adsorption. The adsorption flow rate is 0.6 BV / h. When the resin adsorption volume reaches 40 BV, the resin system adsorption reaches the saturation state, and 4970 g of adsorption liquid is obtained;

[0077] The resin adsorption system is desorbed with dichloromethane, and 24.6 g of 2-azabicyclo[2.2.1]hept-5-en-3-one with a purity of 98.4% is obtained after the desorbed liquid is stripped of solvent;

[0078] Step 2: 4970 g of the adsorption liquid is added to a closed reaction kettle, 497 g of oxygen is introduced, and the temperature is raised to 270 °C for oxidation for 7.0 h to obtain 5031 g of oxidation liquid. The COD concentration of the oxidation liquid is detected to be 6000 mg / L;

[0079] Step 3: The pH of 5031 g of the oxidation liquid is adjusted to 2.0 with 182 g of a hydrochloric acid solution with a mass concentration of 30% to obtain 5134 g of acidified liquid;

[0080] Step 4: At 25 °C, the obtained 5134 g of acidified liquid is introduced into D311 macroporous weakly basic acrylic anion exchange resin for adsorption to obtain 4975 g of purified liquid. The COD concentration of the purified liquid is detected to be 1800 mg / L, and the TOC concentration is 590 ppm;

[0081] Step 5: The pH of 4975 g of the purified liquid is adjusted to 8.0 with 177.5 g of a liquid alkali with a mass concentration of 32%, and then spray drying is carried out at 130 °C to obtain 726 g of crude product. The water content of the crude product is detected to be 0.6%;

[0082] Step 6: Add 1452 g of methanol to 726 g of the crude product, then adjust the pH to 1.5 with 30% hydrochloric acid by mass, stir for 1.5 h at 15 °C, and filter to obtain 1542 g of the separation liquid and 621 g of the mixed salt;

[0083] Step 7: Subject 1542 g of the separation liquid to atmospheric distillation, and stop distillation when the top temperature of the distillation column reaches 120 °C to obtain 84 g of methanesulfonic acid with a purity of 98.61%;

[0084] Step 8: Dissolve the obtained 621 g of the mixed salt in water, perform nanofiltration and dehydration to obtain 513 g of sodium chloride with a purity of 98.6% and 101 g of sodium sulfate with a purity of 98.2%.

[0085] Example 3

[0086] This example provides a method for treating the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one. Among them, the pH of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one is 6.72, the concentration of COD is 80000 mg / L, the concentration of TOC is 35000 mg / L, the mass concentration of 2-azabicyclo[2.2.1]hept-5-en-3-one is 0.6%, the mass concentration of NaCl is 9.96%, the mass concentration of Na2SO4 is 2.86%, the mass concentration of sodium methyl sulfinate is 2.69%, and the mass concentration of the total salt is 19.81%.

[0087] The treatment method includes the following steps:

[0088] Step 1: At 25 °C, pass 5000 g of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one into Diaion HP20 non-polar styrene-based macroporous adsorption resin for adsorption, and the adsorption flow rate is 0.8 BV / h. When the resin adsorption volume reaches 35 BV, the resin system adsorption reaches the saturation state to obtain 4960 g of the adsorption liquid;

[0089] Use dichloromethane to desorb the resin adsorption system, and after desolventizing the desorption liquid, obtain 29.4 g of 2-azabicyclo[2.2.1]hept-5-en-3-one with a purity of 98.4%;

[0090] Step 2: Add 4960 g of the adsorption liquid to a closed reaction kettle, introduce 248 g of oxygen, heat up to 260 °C and oxidize for 6.5 h to obtain 5018 g of the oxidation liquid, and detect that the COD concentration of the oxidation liquid is 6800 mg / L;

[0091] Step 3: Adjust the pH of 5018 g of the oxidation liquid to 1.1 with 191 g of 30% hydrochloric acid solution by mass to obtain 5120 g of the acidified liquid;

[0092] Step 4: At 15°C, pass the obtained 5120 g of acidified solution through D311 macroporous weakly basic acrylic acid-based anion exchange resin for adsorption to obtain 4959 g of purified solution. The COD concentration of the purified solution is detected to be 1850 mg / L, and the TOC concentration is 612 ppm.

[0093] Step 5: Use 176.8 g of liquid caustic soda with a mass concentration of 32% to adjust the pH of 4959 g of purified solution to 7.0, and then perform spray drying at 130°C to obtain 866 g of crude product. The moisture content of the crude product is detected to be 0.63%.

[0094] Step 6: Add 1732 g of methanol to 866 g of crude product, then adjust the pH to 1.0 with hydrochloric acid with a mass concentration of 30%, stir at 5°C for 2.0 h, and filter to obtain 1847 g of separation liquid and 733 g of mixed salt.

[0095] Step 7: Subject 1847 g of separation liquid to atmospheric distillation, and stop distillation when the top temperature of the distillation column reaches 130°C to obtain 115.3 g of methanesulfonic acid with a purity of 98.57%.

[0096] Step 8: Dissolve the obtained 733 g of mixed salt in water, perform nanofiltration and dehydration to obtain 575 g of sodium chloride with a purity of 98.3% and 140 g of sodium sulfate with a purity of 98.35%.

[0097] Comparative Example 1

[0098] This comparative example provides a method for treating the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one. The only difference from Example 1 is that the macroporous adsorption resin used in Step 1 is HYA-108, and the rest are exactly the same.

[0099] The treatment method includes the following steps:

[0100] Step 1: At 25°C, pass 5000 g of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one through HYA-108 macroporous adsorption resin for adsorption. The adsorption flow rate is 0.7 BV / h. When the resin adsorption volume reaches 1 BV, the concentration of 2-azabicyclo[2.2.1]hept-5-en-3-one in the adsorbed water is detected to be 0.599%, indicating that the HYA-108 macroporous adsorption resin has no adsorption effect on 2-azabicyclo[2.2.1]hept-5-en-3-one.

[0101] Step 2: Add 4980 g of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one to a closed reaction kettle, introduce 250 g of oxygen, heat up to 250°C and oxidize for 6.0 h to obtain 5010 g of oxidation solution. The COD concentration of the oxidation solution is detected to be 8500 mg / L.

[0102] Step 3: Adjust the pH of 5010 g of the oxidation solution to 1.0 with 215.5 g of a hydrochloric acid solution with a mass concentration of 30% to obtain 5155 g of an acidified solution;

[0103] Step 4: At 15 °C, pass the obtained 5155 g of the acidified solution through D311 macroporous weakly basic acrylic anion exchange resin for adsorption to obtain 5140 g of a purified solution. The COD concentration of the purified solution is detected to be 8000 mg / L, and the TOC concentration is 4480 ppm;

[0104] Step 5: Use 158 g of a liquid caustic soda with a mass concentration of 32% to adjust the pH of 5140 g of the purified solution to 7.0, and then perform spray drying at 110 °C to obtain 980 g of a crude product. The moisture content of the crude product is detected to be 1.0%;

[0105] Step 6: Add 1960 g of methanol to 980 g of the crude product, then adjust the pH to 1.0 with hydrochloric acid with a mass concentration of 30%, stir at 5 °C for 2.0 h, and filter to obtain 2215 g of a separation liquid and 723 g of a mixed salt;

[0106] Step 7: Subject the 2215 g of the separation liquid to atmospheric distillation, and stop distillation when the top temperature of the distillation column reaches 110 °C to obtain 255 g of methanesulfonic acid with a purity of 49.56%;

[0107] Step 8: Dissolve the obtained 723 g of the mixed salt in water, perform nanofiltration and dehydration to obtain 555 g of sodium chloride with a purity of 90.5% and 166 g of sodium sulfate with a purity of 86.14%.

[0108] Comparative Example 2

[0109] This comparative example provides a method for treating the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one. The only difference from Example 2 is that the macroporous adsorption resin used in Step 4 is D318, and the rest are exactly the same.

[0110] The treatment method includes the following steps:

[0111] Step 1: At 30 °C, pass 5000 g of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one through Diaion HP20 non-polar styrene-based macroporous adsorption resin for adsorption. The adsorption flow rate is 0.6 BV / h. When the resin adsorption volume reaches 40 BV, the resin system adsorption reaches a saturated state to obtain 4975 g of an adsorption liquid;

[0112] Use dichloromethane to desorb the resin adsorption system, and after desolventizing the desorbed liquid, obtain 24.3 g of 2-azabicyclo[2.2.1]hept-5-en-3-one with a purity of 98.4%;

[0113] Step 2: Add 4975 g of the adsorption solution into a closed reaction kettle, introduce 497 g of oxygen, heat up to 270 °C and oxidize for 7.0 h to obtain 5031 g of the oxidation solution. Detect that the COD concentration of the oxidation solution is 6000 mg / L;

[0114] Step 3: Adjust the pH of 5031 g of the oxidation solution to 2.0 with 181.8 g of a hydrochloric acid solution with a mass concentration of 30% to obtain 5132 g of the acidified solution;

[0115] Step 4: At 25 °C, pass the obtained 5132 g of the acidified solution through D318 macroporous weakly basic acrylic anion exchange resin for adsorption to obtain 5130 g of the purified solution. Detect that the COD concentration of the purified solution is 5594 mg / L and the TOC concentration is 3172 ppm;

[0116] Step 5: Use 204 g of a liquid caustic soda with a mass concentration of 32% to adjust the pH of 5130 g of the purified solution to 8.0, and then perform spray drying at 130 °C to obtain 934 g of the crude product. Detect that the moisture content of the crude product is 0.6%;

[0117] Step 6: Add 1868 g of methanol to 934 g of the crude product, then adjust the pH to 1.0 with a hydrochloric acid solution with a mass concentration of 30%, stir at 15 °C for 2.0 h, and filter to obtain 2002 g of the separation solution and 800 g of the mixed salt;

[0118] Step 7: Distill the 2002 g of the separation solution under normal pressure and stop distillation when the top temperature of the distillation column reaches 120 °C to obtain 134 g of methanesulfonic acid with a purity of 71.50%;

[0119] Step 8: Dissolve the obtained 800 g of the mixed salt in water, perform nanofiltration and dehydration to obtain 623 g of sodium chloride with a purity of 72.42% and 175 g of sodium sulfate with a purity of 60%.

[0120] Comparative Example 3

[0121] This comparative example provides a method for treating the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one. The only difference from Example 3 is that the oxidation temperature in Step 2 is 200 °C and the oxidation time is 7 h, and the rest are exactly the same.

[0122] The treatment method includes the following steps:

[0123] Step 1: At 25 °C, pass 5000 g of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one through Diaion HP20 non-polar styrene-based macroporous adsorption resin for adsorption. The adsorption flow rate is 0.8 BV / h. When the resin adsorption volume reaches 35 BV, the resin system adsorption reaches the saturation state to obtain 4958 g of the adsorption solution;

[0124] The resin adsorption system was desorbed with dichloromethane, and after the desorption liquid was stripped, 29.1 g of 2-azabicyclo[2.2.1]hept-5-en-3-one with a purity of 98.4% was obtained;

[0125] Step 2: Add 4958 g of the adsorption liquid into a closed reaction kettle, introduce 248 g of oxygen, heat up to 200 °C and oxidize for 7.0 h to obtain 5184 g of the oxidation liquid. The COD concentration of the oxidation liquid was detected to be 41640 mg / L;

[0126] Step 3: Adjust the pH of 5184 g of the oxidation liquid to 1.1 with 188 g of a hydrochloric acid solution with a mass concentration of 30% to obtain 5312 g of the acidified liquid;

[0127] Step 4: At 15 °C, pass the obtained 5312 g of the acidified liquid through D311 macroporous weakly basic acrylic anion exchange resin for adsorption to obtain 5309 g of the purified liquid. The COD concentration of the purified liquid was detected to be 40580 mg / L, and the TOC concentration was 11936 ppm;

[0128] Step 5: Use 183.9 g of a liquid caustic soda with a mass concentration of 32% to adjust the pH of 5309 g of the purified liquid to 7.0, and then perform spray drying at 130 °C to obtain 1042 g of the crude product. The water content of the crude product was detected to be 0.63%;

[0129] Step 6: Add 2084 g of methanol to 1042 g of the crude product, then adjust the pH to 1.0 with hydrochloric acid with a mass concentration of 30%, stir at 5 °C for 2.0 h, and filter to obtain 2298 g of the separation liquid and 824 g of the mixed salt;

[0130] Step 7: Distill the 2298 g of the separation liquid at atmospheric pressure and stop distillation when the top temperature of the distillation column reaches 130 °C to obtain 212 g of methanesulfonic acid with a purity of 45.19%;

[0131] Step 8: Dissolve the obtained 824 g of the mixed salt in water, perform nanofiltration and dehydration to obtain 650 g of sodium chloride with a purity of 78.3% and 178 g of sodium sulfate with a purity of 80.35%.

[0132] In summary, through the treatment method of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one provided by the present invention, various effective components in the wastewater can be recovered one by one, and by-products with high added value such as 2-azabicyclo[2.2.1]hept-5-en-3-one with a purity greater than 98%, methanesulfonic acid, sodium chloride, and sodium sulfate are separated, effectively reducing the treatment cost of the wastewater, realizing the resource utilization of the wastewater, completely solving the technical problem of the difficult treatment of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one, conforming to the development trend of energy conservation, consumption reduction, and environmental protection, being convenient for industrial implementation, and having extremely high practical value.

[0133] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, or improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A treatment method for the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one, characterized in that, It includes the following steps: Step a: Pass the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one into a non-polar styrene-based macroporous adsorption resin for adsorption to obtain an adsorption solution; Step b: Pass oxygen into the adsorption solution and perform oxidation at 250°C to 270°C to obtain an oxidation solution; Step c: Adjust the pH of the oxidation solution to strong acidity to obtain an acidified solution; Pass the acidified solution into a macroporous weakly basic acrylic anion exchange resin for adsorption to obtain a purified solution; Step d: Adjust the pH of the purified solution to weak alkalinity, concentrate and dry to obtain a crude product; add an alcohol solvent to the crude product, adjust the pH to strong acidity, perform solid-liquid separation to obtain a separation solution and a mixed salt; Step e: Desolventize the separation solution to obtain methanesulfonic acid; Among them, the pore diameter of the non-polar styrene-based macroporous adsorption resin is The pore diameter of the macroporous weakly basic acrylic anion exchange resin is 0.40 mm to 0.70 mm.

2. The treatment method of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one as described in claim 1, characterized in that, In step a, the non-polar styrene-based macroporous adsorption resin is Diaion HP 20; and / or In step a, the adsorption flow rate is 0.6 BV / h to 0.8 BV / h; and / or In step a, the adsorption temperature is 25°C to 30°C.

3. The treatment method of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one as described in claim 1, characterized in that, In step a, use dichloromethane to desorb the adsorbed non-polar styrene-based macroporous adsorption resin, desolventize the desorption solution, and dry to obtain 2-azabicyclo 2.2.1]hept-5-en-3-one product.

4. The treatment method of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one according to claim 1, characterized in that, In step b, the oxidation time is 6 h to 7 h; and / or In step b, the mass of oxygen passed in is 0.05 to 0.10 times the mass of the adsorption solution.

5. The treatment method of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one as described in claim 1, characterized in that, In step c, the strong acidity means a pH value of 1 to 2; and / or In step c, the macroporous weakly basic acrylic anion exchange resin is D311.

6. The treatment method of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one as described in claim 1, characterized in that, In step c, the adsorption flow rate is 1.3 BV / h to 1.5 BV / h; and / or In step c, the adsorption temperature is 15°C to 25°C.

7. The treatment method of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one as described in claim 1, characterized in that, In step d, the weak alkalinity means a pH value of 7 to 8; and / or In step d, the concentration and drying are carried out by spray drying; and / or In step d, the alcohol solvent is methanol or ethanol.

8. The treatment method of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one as described in claim 1 or 7, characterized in that, In step d, the addition amount of the alcohol solvent is 1.5 to 2.0 times the mass of the crude product; and / or In step d, the strong acidity means a pH value of 1 to 2; and / or In step d, the temperature of the solid-liquid separation is 5°C to 15°C.

9. The treatment method of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one as described in claim 1, characterized in that In step e, desolventize the separation solution by atmospheric distillation, and stop distillation when the top temperature of the distillation column reaches 110°C to 130°C.

10. The treatment method of the production wastewater of 2-azabicyclo[2.2.1]hept-5-en-3-one as described in claim 1, characterized in that, It also includes step f: subject the mixed salt to nanofiltration to obtain sodium chloride and sodium sulfate.