Method for comprehensive recovery and treatment of waste water in preparation of 7-ANCA
By adjusting the pH of wastewater with phosphoric acid or hydrochloric acid during the preparation of 7-ANCA, preparing tricalcium phosphate by precipitation, alkali-displacement phase separation, and cation exchange resin separation, the problems of wastewater resource waste and environmental pollution are solved, and the efficient recovery and recycling of components in wastewater are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANXI WEIQIDA PHARMA IND
- Filing Date
- 2024-10-31
- Publication Date
- 2026-08-04
AI Technical Summary
The direct discharge of wastewater generated during the preparation of 7-ANCA leads to high pressure on wastewater treatment, serious environmental pollution, and significant waste of resources, especially since components such as triethylamine, phosphate, and methanesulfonic acid have not been effectively recovered and utilized.
Methanol is recovered by vacuum distillation after adjusting the pH of the wastewater with phosphoric acid or hydrochloric acid, high-purity tricalcium phosphate is prepared by precipitation, triethylamine is recovered by temperature-controlled phase separation with alkali replacement, and methanesulfonic acid and hydrochloric acid are separated by cation exchange resin, so as to achieve comprehensive recovery and utilization of the components in the wastewater.
It reduces wastewater treatment costs, decreases environmental pollution, and enables the recycling of resources such as triethylamine, brine, and hydrochloric acid, thereby reducing raw material costs.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of pharmaceutical and chemical technology, and relates to a comprehensive recycling and treatment method for wastewater in the preparation process of 7-ANCA. Background Technology
[0002] Since their inception, cephalosporin antibiotics have held a leading position in the antibiotic field due to their strong antibacterial ability and few side effects, accounting for more than 60% of the market. Cephalosporin antibiotics are mainly obtained by introducing different groups on the 7-amino, 3-C and 4-carboxyl groups of key cores such as 7-ANCA, 7-ADCA, 7-ACA, and GCLE.
[0003] 7-ANCA (7-amino-3-agno-3-cephalocyclo-4-carboxylic acid) is a core intermediate in the synthesis of third-generation cephalosporins cefazolin and cefbufen, and also a core raw material for the next-generation antibiotic cefuroxime. Currently, there are two main directions in the preparation of 7-ANCA:
[0004] (1) It is prepared by deesterification at the 3-position of cephalosporin intermediate 7-ACA and further oxidation to remove hydroxymethyl groups. However, this process route has expensive raw materials and low yield of dehydroxymethylation, and is limited to laboratory research. The reaction process is as follows:
[0005]
[0006] (2) Using penicillin G as a raw material, ring expansion and modification were carried out. Penicillin G was cyclized through esterification, sulfonation, ring opening, oxidation, hydroxyl protection, bromination, and rearrangement with a deprotecting agent to prepare 3-hydroxycephalosporin. The cephalosporin ring double bond was then reduced with sodium borohydride to obtain HCA (3-hydroxy-7β-phenylacetamide-3-non-3-cephalosporane-2-carboxylic acid diphenylmethyl ester). HCA was then esterified with triethylamine-catalyzed methanesulfonyl chloride, followed by triethylamine-catalyzed ester elimination, while simultaneously reducing the cephalosporin ring double bond to obtain PNCD (3-hydro-7β-phenylacetamide-3-non-3-cephalosporane-2-carboxylic acid diphenylmethyl ester). PNCD underwent decarboxylation and amino protecting group removal to obtain 7-ANCA. The reaction process is as follows:
[0007]
[0008]
[0009] Although the process route using penicillin G as a raw material is long, it has advantages such as simple process, high yield, and low raw material price, and is currently the common process route for the industrial production of 7-ANCA in China. However, this route generates a lot of waste liquid. In the process of preparing PNCD from HCA, the hydroxyl groups at the 2 and 3 positions react with methanesulfonyl chloride through triethylamine catalysis to form methanesulfonate. Then, under an alkaline environment, a large amount of triethylamine is used to catalyze the ester elimination reaction, eliminating the methanesulfonate at the 3 position and reducing the double bond of the cephalosporin ring to obtain PNCD. After the reaction, excess triethylamine is neutralized with phosphoric acid. Water and organic solvent are added to the reaction solution for phase separation. The product extracted from the organic phase is used for the next reaction. The wastewater generated from the phase separation is currently discharged into the sewage system. This wastewater generally contains 15%–18% triethylamine, 16%–18% phosphate, 3%–4% methanesulfonic acid, 18%–20% methanol, and the remainder is sodium chloride, water, trace amounts of HCA and PNCD, by weight percentage.
[0010] Direct discharge of the aforementioned wastewater into sewage treatment plants places immense pressure on these facilities and causes water and soil pollution. Furthermore, the wastewater contains expensive triethylamine and valuable phosphates with significant applications across various fields. For example, tricalcium phosphate is used in the food, feed, agriculture, and pharmaceutical industries and is harmless to humans. Methanesulfonates are also widely used in food, pharmaceuticals, chemicals, optics, and agriculture. Industrial sodium chloride has recycling value, and triethylamine and methanol can be recycled in PNCD production. Therefore, direct sewage treatment of this wastewater not only increases treatment costs and pollutes the environment but also represents a significant waste of resources. It is therefore necessary to extract the components from this wastewater to reduce pollution, lower wastewater treatment costs, and conserve resources while creating value. Summary of the Invention
[0011] Therefore, the purpose of this invention is to provide a comprehensive wastewater recovery and treatment method in the preparation process of 7-ANCA. This method is simple, low-cost, and easy to operate industrially. It utilizes phosphate ions in the wastewater to prepare high-purity tricalcium phosphate by precipitation; it uses alkali replacement to control temperature and phase separation, and recovers triethylamine through dehydration and distillation; it removes dissolved sodium ions through resin exchange, and then separates methanesulfonic acid and hydrochloric acid by distillation, thereby achieving comprehensive recovery and utilization of the components in the wastewater. The recovered triethylamine, brine, and hydrochloric acid can be used for recycling in the process.
[0012] According to the present invention, the comprehensive recycling and treatment method for wastewater in the preparation process of 7-ANCA includes:
[0013] (1) Methanol recovery
[0014] The pH of the wastewater was adjusted to 5.5–6.8 using phosphoric acid or hydrochloric acid, and then crude methanol and methanol-removed wastewater were obtained by vacuum distillation. The crude methanol was dehydrated by calcium oxide and then purified by distillation to obtain purified methanol.
[0015] (2) Recovery of tricalcium phosphate
[0016] A calcium source was added to the above methanol removal wastewater at room temperature, and the mixture was stirred to react. A white tricalcium phosphate precipitate was formed. The filtrate was collected by filtration, and the tricalcium phosphate filter cake was washed with a water:alcohol solution at a volume ratio of 1:2 to 1:8. The filter cake was rinsed with purified water and dried to obtain purified tricalcium phosphate.
[0017] (3) Recovery of triethylamine
[0018] Add sodium hydroxide or potassium hydroxide to the filtrate collected in step (2) to adjust the pH to 9-14, and perform static phase separation at a temperature of 25℃-40℃. The upper layer is crude triethylamine and the lower layer is brine. Add a dehydrating agent to the crude triethylamine and perform distillation to obtain purified triethylamine.
[0019] (4) Recovery of methanesulfonic acid and hydrochloric acid
[0020] The brine obtained in step (3) above is adjusted to neutral with hydrochloric acid and passed through a cation exchange resin to obtain a strongly acidic flow solution, wherein the sodium ions in the brine are exchanged for hydrogen ions; the strongly acidic flow solution is distilled, wherein the hydrogen chloride tail gas undergoes two-stage absorption treatment, the first stage using water absorption and the second stage using alkaline water absorption, and the bottom of the vessel is cooled to obtain solid methanesulfonic acid.
[0021] Beneficial effects
[0022] The present invention provides a comprehensive wastewater recovery and treatment method in the preparation process of 7-ANCA. This method is simple, low-cost, and easy to operate industrially. It utilizes phosphate ions in the wastewater to prepare high-purity tricalcium phosphate by precipitation; it uses alkali replacement to control temperature and phase separation, and recovers triethylamine through dehydration and distillation; it removes dissolved sodium ions through resin exchange, and then separates methanesulfonic acid and hydrochloric acid by distillation, thereby achieving comprehensive recovery and utilization of the components in the wastewater. The recovered triethylamine, brine, and hydrochloric acid can be recycled in the process.
[0023] This method can effectively reduce the pressure on sewage treatment, reduce environmental pollution, and enable the recycling of auxiliary materials, thereby reducing raw material costs. Detailed Implementation
[0024] The following will describe in detail the comprehensive wastewater recovery and treatment method of the present invention during the preparation of 7-ANCA to facilitate understanding of the invention. However, various modifications can be made to the embodiments of the present invention, and the scope of the invention is not limited to the embodiments described below. The embodiments of the present invention are provided to make this disclosure clear and complete, in order to fully illustrate the invention to those skilled in the art.
[0025] As described above, in the preparation of 7-ANCA, during the preparation of PNCD from HCA, the hydroxyl groups at positions 2 and 3 are esterified with methanesulfonyl chloride by triethylamine to form methanesulfonate. Then, an ester elimination reaction is catalyzed by an excess of triethylamine under alkaline conditions to eliminate the methanesulfonate at position 3, while simultaneously reducing the double bond of the cephalosporin ring to obtain PNCD. After the reaction, excess triethylamine is neutralized with phosphoric acid. Water and organic solvent are added to the reaction solution for phase separation. The product extracted from the organic phase is used for the next reaction, while the wastewater generated from the phase separation is currently discharged into the sewage system. This wastewater generally contains 15%–18% triethylamine, 16%–18% phosphate, 3%–4% methanesulfonic acid, 18%–20% methanol, and the remainder consists of sodium chloride, water, and trace amounts of residual HCA and PNCD, by weight percentage.
[0026] In step (1) of methanol recovery, the pH of the wastewater is adjusted to 5.5-6.8 using phosphoric acid or hydrochloric acid, and then crude methanol and methanol-removed wastewater are obtained by vacuum distillation; the crude methanol is dehydrated by calcium oxide and then purified by distillation to obtain purified methanol.
[0027] Specifically, the pH of the wastewater is adjusted to 5.5–6.8, preferably 6.0–6.5, using phosphoric acid or hydrochloric acid. For example, 85 wt% phosphoric acid or 32 wt% hydrochloric acid is used to adjust the pH of the wastewater to 5.5–6.8, preferably 6.0–6.5. Then, vacuum distillation is carried out at a vacuum of -0.085 to -0.090 MPa and a temperature of 25°C to 36°C to obtain crude methanol and methanol-removed wastewater. The crude methanol is then dehydrated by calcium oxide and then purified by distillation to obtain purified methanol.
[0028] In step (2) of recovering tricalcium phosphate, a calcium source is added to the above-mentioned methanol-removed wastewater at room temperature, the mixture is stirred and reacted, and a white tricalcium phosphate precipitate is formed. The filtrate is collected by filtration, and the tricalcium phosphate filter cake is washed with a solution of water:alcohol at a volume ratio of 1:2 to 1:8. The filter cake is then rinsed with purified water and dried to obtain purified tricalcium phosphate.
[0029] The calcium source can be one or more selected from calcium carbonate, calcium oxide, calcium hydroxide and calcium chloride, preferably calcium oxide, and the amount of calcium source can be calculated according to the molar ratio of calcium ions to phosphate ions in the wastewater of about 3:2; the water:alcohol solution is prepared in a volume ratio of 1:2 to 1:8, wherein the alcohol can be methanol or ethanol; the drying is carried out at a temperature of 90℃ to 110℃ and a vacuum of -0.085 to -0.090 MPa.
[0030] In step (3) of recovering triethylamine, sodium hydroxide or potassium hydroxide is added to the filtrate collected in step (2) to adjust the pH to 9-14, and the liquid temperature is controlled at 25℃-40℃ for static phase separation. The upper layer is crude triethylamine and the lower layer is brine. A dehydrating agent is added to the crude triethylamine for dehydration, and then it is distilled to obtain purified triethylamine.
[0031] Specifically, solid sodium hydroxide or potassium hydroxide is added to the filtrate collected in step (2) to adjust the pH to 9-14, preferably 12-13. Then, the liquid temperature is controlled at 25℃-40℃, preferably 28℃-32℃, for static phase separation. The upper layer yields crude triethylamine, and the lower layer yields brine. The crude triethylamine has a water content of about 1%-5%. Molecular sieves, sodium hydroxide, sodium chloride, and other dehydrating agents can be added to the crude triethylamine for dehydration. Then, distillation is carried out to obtain purified triethylamine with a water content of <0.05% and a purity of >99.9%.
[0032] In step (4) to recover methanesulfonic acid and hydrochloric acid, the brine obtained in step (3) is adjusted to neutral with hydrochloric acid and passed through a cation exchange resin to obtain a strongly acidic flow solution, wherein the sodium ions in the brine are exchanged for hydrogen ions; the strongly acidic flow solution is distilled, wherein the hydrogen chloride tail gas undergoes two-stage absorption treatment, the first stage using water absorption and the second stage using alkaline water absorption, and the bottom of the vessel is cooled to obtain solid methanesulfonic acid.
[0033] The cation exchange resin is a strongly acidic cation exchange resin, such as the LXT-140 cation exchange resin from Gaoling Lanxiao Technology New Materials Co., Ltd. This cation exchange resin is activated to the hydrogen form by soaking in hydrochloric acid before use. The brine obtained in step (3) is adjusted to neutral with hydrochloric acid and passed through the cation exchange resin to obtain a strongly acidic flow solution with a pH value < 1.
[0034] Then, the strongly acidic liquid is transferred to a distillation kettle for atmospheric distillation. The kettle temperature is slowly raised to 120°C, and water is recovered at the top of the column until no fraction is produced. Cooling the distillation kettle yields pale yellow methanesulfonic acid with a content of up to 99.5%. The hydrogen chloride gas in the distillation tail gas is absorbed in a secondary process using water and sodium hydroxide solution. The hydrochloric acid obtained by absorbing hydrogen chloride gas with water has a concentration of 5% and can be used for the activation and regeneration of cation exchange resins. The pH of the hydrogen chloride gas absorbed by the sodium hydroxide solution is neutral and can be used as brine for phase separation in the 7-ANCA preparation process.
[0035] The following examples provide a more detailed description of the comprehensive wastewater recycling and treatment method for the preparation of 7-ANCA according to the present invention. The scope of protection of the present invention is not limited to the following examples. These examples are provided for illustrative purposes only and do not limit the present invention in any way.
[0036] In the preparation of 7-ANCA, the wastewater obtained during the PNCD phase separation process has a pH of 7.5, a triethylamine content of 16%, a phosphate content of 18%, a methanesulfonic acid content of 3.6%, a methanol content of 18%, and the remainder consists of sodium chloride, water, trace amounts of HCA and PNCD.
[0037] Example 1
[0038] (1) Methanol recovery
[0039] Take 2500g of the above wastewater, add 85% phosphoric acid to adjust the pH to 6.5, and use a rotary evaporator to recover 501g of crude methanol (approximately 10% moisture, 90% methanol content, and 99.6% purity) by vacuum distillation under a vacuum of -0.089MPa and 36℃. Collect 1980g of wastewater after solvent removal and 19g of water lost through distillation evaporation. After adding calcium oxide to dehydrate the crude methanol, further distillation yields 431g of finished methanol (0.05% moisture), with a purity of 99.6%, achieving a methanol recovery rate of 95.7%.
[0040] (2) Recovery of tricalcium phosphate
[0041] At room temperature, 398g of solid calcium oxide was slowly added to 1980g of the above desolventized wastewater. After stirring for 10min, a white tricalcium phosphate precipitate was formed. After filtration, 1585g of filtrate was collected.
[0042] The tricalcium phosphate filter cake was washed with 300 ml of a water:methanol solution at a volume ratio of 1:5, and then rinsed with 600 ml of purified water. The solid was dried in a vacuum drying oven at 100°C and a vacuum of -0.085 MPa to constant weight to obtain 721 g of tricalcium phosphate. The tricalcium phosphate content was tested to be 99.3%, and the phosphate recovery rate was 98.2%.
[0043] (3) Recovery of triethylamine
[0044] Solid sodium hydroxide was added to the 1585g filtrate collected in step (2) to adjust the pH to 13. The temperature of the liquid was controlled at 28℃ and the liquid was allowed to stand for phase separation. The upper layer was 401g of crude triethylamine (water content of 1.5%) and the lower layer was 1190g of brine. After adding 20g of molecular sieve to the crude triethylamine for dehydration, it was distilled to obtain 365g of finished triethylamine with a water content of 0.02% and a purity of 99.96%. The yield of triethylamine was 91.25%.
[0045] (4) Recovery of methanesulfonic acid and hydrochloric acid
[0046] The 1190g brine obtained in step (3) above was adjusted to neutral with 32wt% hydrochloric acid and passed through a cation exchange resin column (model LXT-140 cation exchange resin from Gaoling Lanxiao Technology New Materials Co., Ltd., 600ml, height-to-diameter ratio 3:1) at a flow rate of 2BV / h to obtain a strongly acidic flow solution (pH 0.3). In this flow solution, sodium ions in the brine were exchanged for hydrogen ions, and the solution was washed with 1BV of water. The collected wash solution was added to the strongly acidic flow solution, totaling 1812g. Then, the 181g of strongly acidic flow solution was... 2g was transferred to a distillation vessel for atmospheric distillation. The vessel temperature was slowly raised to 120℃, and water was recovered at the top of the column. Distillation was stopped when no fraction was produced at the top of the column. The distillation vessel was then cooled to obtain 86g of pale yellow methanesulfonic acid, with a yield of 95.5%. The hydrogen chloride gas in the distillation tail gas was absorbed in a secondary process using water and sodium hydroxide solution. The hydrochloric acid obtained by absorbing hydrogen chloride gas with water had a concentration of 5% and could be used for the activation and regeneration of cation exchange resins. The pH of the hydrogen chloride gas absorbed by the sodium hydroxide solution was neutral and could be used as a brine for phase separation in the preparation of 7-ANCA.
[0047] Example 2
[0048] (1) Methanol recovery
[0049] Take 2500g of the above wastewater, add 32% hydrochloric acid to adjust the pH to 6.0, and use a rotary evaporator to recover 521g of crude methanol by vacuum distillation under a vacuum of -0.089MPa and a temperature of 36℃. Collect 1962g of wastewater after solvent removal, and lose 17g of water through distillation evaporation. After adding calcium oxide to dehydrate the crude methanol, further distillation yields 419g of finished methanol (0.02% moisture), with a purity of 99.9%, and a methanol recovery rate of 93.1%.
[0050] (2) Recovery of tricalcium phosphate
[0051] At room temperature, 526g of solid calcium hydroxide was slowly added to 1962g of the above desolventized wastewater. After stirring for 10min, a white tricalcium phosphate precipitate was formed. After filtration, 1637g of filtrate was collected.
[0052] The tricalcium phosphate filter cake was washed with 300 ml of a water:methanol solution at a volume ratio of 1:8, and then rinsed with 600 ml of purified water. The solid was dried in a vacuum drying oven at 100°C and a vacuum of -0.085 MPa to constant weight to obtain 713 g of tricalcium phosphate. The tricalcium phosphate content was tested to be 99.3%, and the phosphate recovery rate was 97.1%.
[0053] (3) Recovery of triethylamine
[0054] Solid sodium hydroxide was added to the 1637g filtrate collected in step (2) to adjust the pH to 13. The temperature of the liquid was controlled at 28℃ and the liquid was allowed to stand for phase separation. The upper layer was 350g of crude triethylamine (water content of 2.4%) and the lower layer was 1287g of brine. After adding 20g of molecular sieve to the crude triethylamine for dehydration, it was distilled to obtain 337g of finished triethylamine with 0.05% water content and 99.92% purity. The yield of triethylamine was 84.25%.
[0055] (4) Recovery of methanesulfonic acid and hydrochloric acid
[0056] The 1287g brine obtained in step (3) above was adjusted to neutral with 32wt% hydrochloric acid and passed through a cation exchange resin column (same as in Example 1) at a flow rate of 2BV / h to obtain a strongly acidic flow solution (pH 0.6). The sodium ions in the brine were exchanged for hydrogen ions, and the brine was washed with 1BV of water. The collected wash liquid was added to the strongly acidic flow solution, totaling 1890g. Then, the strongly acidic flow solution was transferred to a distillation kettle for atmospheric distillation. The kettle temperature was slowly raised to 120°C, and water was recovered at the top of the column. Distillation was stopped when no fraction was produced at the top of the column. The distillation kettle was cooled to obtain 85g of pale yellow methanesulfonic acid, with a yield of 94.4%. The hydrogen chloride gas in the distillation tail gas was absorbed in a secondary process using water and sodium hydroxide solution.
[0057] Example 3
[0058] (1) Methanol recovery
[0059] Take 2500g of the above wastewater, add 85% phosphoric acid to adjust the pH to 6.5, and use a rotary evaporator to recover 452g of crude methanol (approximately 8% moisture, 92% methanol content, and 99.7% methanol purity) by vacuum distillation under a vacuum of -0.089MPa and 30℃. Collect 2037g of wastewater after solvent removal, and lose 11g of water through distillation evaporation. After adding calcium oxide to dehydrate the crude methanol, further distillation yields 414g of finished methanol (0.03% moisture), with a purity of 99.9%, achieving a methanol recovery rate of 92%.
[0060] (2) Recovery of tricalcium phosphate
[0061] At room temperature, 788g of solid calcium chloride was slowly added to 2037g of the above desolventized wastewater. After stirring for 10min, a white tricalcium phosphate precipitate was formed. After filtration, 1864g of filtrate was collected.
[0062] The tricalcium phosphate filter cake was washed with 300 ml of a water:methanol solution at a volume ratio of 1:8, and then rinsed with 600 ml of purified water. The solid was dried in a vacuum drying oven at 100°C and a vacuum of -0.085 MPa to constant weight to obtain 725 g of tricalcium phosphate. The tricalcium phosphate content was tested to be 99.6%, and the phosphate recovery rate was 98.8%.
[0063] (3) Recovery of triethylamine
[0064] Solid sodium hydroxide was added to the 1864g filtrate collected in step (2) to adjust the pH to 12. The temperature of the liquid was controlled at 30℃ and the liquid was allowed to stand for phase separation. The upper layer was 431g of crude triethylamine (water content of 1.7%) and the lower layer was 1433g of brine. After adding 20g of molecular sieve to the crude triethylamine for dehydration, it was distilled to obtain 359g of finished triethylamine with a water content of 0.02% and a purity of 99.97%. The yield of triethylamine was 89.75%.
[0065] (4) Recovery of methanesulfonic acid and hydrochloric acid
[0066] The 1433g brine obtained in step (3) above was adjusted to neutral with 32wt% hydrochloric acid and passed through a cation exchange resin column (same as in Example 1) at a flow rate of 2BV / h to obtain a strongly acidic flow solution (pH 0.5). The sodium ions in the brine were exchanged for hydrogen ions, and 1BV of water was used for top washing. The collected top wash liquid was added to the strongly acidic flow solution, totaling 2036g. Then, the strongly acidic flow solution was transferred to a distillation kettle for atmospheric distillation. The kettle temperature was slowly raised to 120°C, and water was recovered at the top of the column. Distillation was stopped when no fraction was produced at the top of the column. The distillation kettle was cooled to obtain 81g of pale yellow methanesulfonic acid, with a yield of 90%. The hydrogen chloride gas in the distillation tail gas was absorbed in a secondary process using water and sodium hydroxide solution.
Claims
1. A comprehensive wastewater recovery and treatment method in the preparation process of 7-ANCA, comprising: (1) Methanol recovery The pH of the wastewater was adjusted to 5.5–6.8 using phosphoric acid or hydrochloric acid, and then crude methanol and methanol-removed wastewater were obtained by vacuum distillation. The crude methanol was dehydrated by calcium oxide and then purified by distillation to obtain purified methanol. (2) Recovery of tricalcium phosphate A calcium source was added to the above methanol removal wastewater at room temperature, and the mixture was stirred to react. A white tricalcium phosphate precipitate was formed. The filtrate was collected by filtration, and the tricalcium phosphate filter cake was washed with a water:alcohol solution at a volume ratio of 1:2 to 1:
8. The filter cake was rinsed with purified water and dried to obtain purified tricalcium phosphate. (3) Recovery of triethylamine Add sodium hydroxide or potassium hydroxide to the filtrate collected in step (2) to adjust the pH to 9-14, and perform static phase separation at a temperature of 25℃-40℃. The upper layer is crude triethylamine and the lower layer is brine. Add a dehydrating agent to the crude triethylamine and perform distillation to obtain purified triethylamine. (4) Recovery of methanesulfonic acid and hydrochloric acid The brine obtained in step (3) above is adjusted to neutral with hydrochloric acid and passed through a cation exchange resin to obtain a strongly acidic flow solution, wherein the sodium ions in the brine are exchanged for hydrogen ions; the strongly acidic flow solution is distilled, wherein the hydrogen chloride tail gas undergoes two-stage absorption treatment, the first stage using water absorption and the second stage using alkaline water absorption, and the bottom of the vessel is cooled to obtain solid methanesulfonic acid.
2. The comprehensive wastewater recovery and treatment method in the preparation process of 7-ANCA according to claim 1, characterized in that, The wastewater is generated during the preparation of PNCD (3-hydro-7β-phenylacetamide-3-non-3-cephalosporane-2-carboxylic acid diphenylmethyl ester) from HCA (3-hydroxy-7β-phenylacetamide-3-non-3-cephalosporane-2-carboxylic acid diphenylmethyl ester). The wastewater contains 15%–18% triethylamine, 16%–18% phosphate, 3%–4% methanesulfonic acid, 18%–20% methanol, and the remainder is sodium chloride, water, and trace amounts of HCA and PNCD, by weight percentage.
3. The comprehensive wastewater recovery and treatment method in the preparation process of 7-ANCA according to claim 1, characterized in that, in In step (1) of recovering methanol, the pH of the wastewater is adjusted to 5.5 to 6.8 using phosphoric acid or hydrochloric acid, and then vacuum distillation is carried out at a vacuum of -0.085 to -0.090 MPa and a temperature of 25°C to 36°C to obtain crude methanol and methanol-removed wastewater. The crude methanol is then dehydrated by calcium oxide and then purified by distillation to obtain purified methanol.
4. The comprehensive wastewater recovery and treatment method in the preparation process of 7-ANCA according to claim 3, characterized in that, in In step (1) of recovering methanol, the pH of the wastewater is adjusted to 6.0-6.5 using 85wt% phosphoric acid or 32wt% hydrochloric acid. Then, it is subjected to vacuum distillation at -0.085 to -0.090 MPa and 25℃ to 36℃ to obtain crude methanol and methanol-removed wastewater. The crude methanol is then dehydrated with calcium oxide and then purified by distillation to obtain purified methanol.
5. The comprehensive wastewater recovery and treatment method in the preparation process of 7-ANCA according to claim 1, characterized in that, in In step (2) to recover tricalcium phosphate, the calcium source is one or more selected from calcium carbonate, calcium oxide, calcium hydroxide and calcium chloride.
6. The comprehensive wastewater recovery and treatment method in the preparation process of 7-ANCA according to claim 5, characterized in that, in In step (2) the recovery of tricalcium phosphate, the water: alcohol solution is prepared in a volume ratio of 1:2 to 1:8, wherein the alcohol is methanol or ethanol; the drying is carried out at a temperature of 90℃ to 110℃ and a vacuum of -0.085 to -0.090 MPa.
7. The comprehensive recycling and treatment method for wastewater during the preparation of 7-ANCA according to claim 1, characterized in that, in In step (3) of the recovery of triethylamine, solid sodium hydroxide or potassium hydroxide is added to the filtrate collected in step (2) to adjust the pH to 12-13. Then, the liquid temperature is controlled at 28℃-32℃ for static phase separation. The upper layer is crude triethylamine and the lower layer is brine. The crude triethylamine has a water content of 1%-5%. After adding molecular sieve, sodium hydroxide or sodium chloride dehydrating agent to the crude triethylamine for dehydration, it is subjected to distillation to obtain purified triethylamine with a water content of <0.05% and a purity of >99.9%.
8. The comprehensive recycling and treatment method for wastewater during the preparation of 7-ANCA according to claim 1, characterized in that, in In step (4), when recovering methanesulfonic acid and hydrochloric acid, the cation exchange resin is a strong acidic cation exchange resin, which is activated by soaking in hydrochloric acid to the hydrogen form before use.
9. The comprehensive recycling and treatment method for wastewater during the preparation of 7-ANCA according to claim 1, characterized in that, in In step (4), the strongly acidic liquid is transferred to a distillation kettle for atmospheric distillation. The kettle temperature is slowly raised to 120°C. Water is recovered at the top of the column until no fraction is produced. The distillation kettle is cooled to obtain pale yellow methanesulfonic acid. Hydrogen chloride gas in the distillation tail gas is absorbed in a secondary process using water and sodium hydroxide solution.
10. The comprehensive recycling and treatment method for wastewater during the preparation of 7-ANCA according to claim 1, characterized in that, in In step (1) of recovering methanol, the pH of the wastewater is adjusted to 5.5 to 6.8 using phosphoric acid or hydrochloric acid, and then vacuum distillation is carried out at a vacuum of -0.085 to -0.090 MPa and a temperature of 25°C to 36°C to obtain crude methanol and methanol-removed wastewater. The crude methanol is dehydrated by calcium oxide and then purified by distillation to obtain purified methanol. In step (2) of recovering tricalcium phosphate, the calcium source is one or more selected from calcium carbonate, calcium oxide, calcium hydroxide and calcium chloride, and the water:alcohol solution is in a volume ratio of 1:2 to 1:8, wherein the alcohol is methanol or ethanol; the drying is carried out at a temperature of 90℃ to 110℃ and a vacuum of -0.085 to -0.090 MPa. In step (3) of the triethylamine recovery, solid sodium hydroxide or potassium hydroxide is added to the filtrate collected in step (2) to adjust the pH to 12-13. Then, the liquid temperature is controlled at 28℃-32℃ for static phase separation. The upper layer is crude triethylamine and the lower layer is brine. The crude triethylamine has a water content of 1%-5%. After adding molecular sieve, sodium hydroxide or sodium chloride dehydrating agent to the crude triethylamine for dehydration, it is subjected to distillation to obtain purified triethylamine with a water content of <0.05% and a purity of >99.9%. In step (4) to recover methanesulfonic acid and hydrochloric acid, the cation exchange resin is a strong acid cation exchange resin, which is activated by soaking in hydrochloric acid to the hydrogen form before use; the strong acid flow liquid is transferred to a distillation kettle for atmospheric distillation, the kettle temperature is slowly raised to 120°C, water is recovered at the top of the column until no fraction is produced at the top of the column, the distillation kettle is cooled to obtain pale yellow methanesulfonic acid, and the hydrogen chloride gas in the distillation tail gas is absorbed in a secondary process using water and sodium hydroxide solution.