Method for recovering cefotaxime acid from cefotaxime sodium mother liquor

Abstract

The invention provides a method for recovering cefotaxime acid from a cefotaxime sodium mother solution, which comprises the following steps: concentrating the cefotaxime sodium mother solution to obtain a concentrated mother solution; adjusting the pH value of the concentrated mother liquor by using acid, and then mixing the concentrated mother liquor and water in a microporous mixer to obtain a mixed liquor; standing the mixed solution, separating to obtain a water phase, adding a decolorizing agent or a filter aid into the water phase, stirring, and filtering to obtain filtrate; washing the decolorizing agent and the filter aid with water, and merging into the filtrate; adding the filtrate and acid into a dispersing agent at the same time, and separating out crystals; and adjusting the pH value for growing crystals, filtering after growing the crystals to obtain crystals, washing and drying to obtain the cefotaxime acid product. According to the method, the concentrated mother liquor and the water are mixed through the microporous mixer, cefotaxime in the concentrated mother liquor can be effectively extracted, the recovery rate of cefotaxime acid is increased, the crystallization method that filtrate and acid are added into the dispersing agent at the same time is adopted, post-treatment of crystallization liquid is facilitated, the obtained product is high in quality, and the quality requirement of enterprises is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of medicine, in particular to a method for recovering cefotaxime acid from cefotaxime sodium mother liquor. BACKGROUND

[0002] Cefotaxime sodium is a third-generation cephalosporin, which has significant effect on gram-negative bacteria, especially enterobacterium, and is mainly used for treating respiratory system infection, urinary system infection, biliary tract and intestinal tract infection, skin and soft tissue infection, burn and bone joint infection caused by sensitive bacteria.

[0003] Cefotaxime sodium is easily soluble in water and slightly soluble in ethanol, and its chemical formula is C 16 H 16 N5Na07S2, and its chemical name is (6R, 7R)-3-[(acetyloxy) methyl]-7-[2-(2-aminothiazole-4-yl)-2-(methoxyimino) acetylamino]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-methane sodium salt, and its molecular weight is 477.447, and its structural formula is as follows:

[0004]

[0005] In the prior art, the crystallization mother liquor of cefotaxime sodium is directly used for distillation recovery of an organic solvent, and there are few technical methods for recovering cefotaxime acid from the cefotaxime sodium mother liquor. The mother liquor contains 10% to 14% of the effective component cefotaxime which has not been crystallized out, resulting in waste of the effective component in the mother liquor and difficulty in recovery of the organic solvent. In the technical solution disclosed in the patent document CN118894870B (a clean recovery process of cefotaxime acid mother liquor), the starting material is cefotaxime acid mother liquor. In this scheme, the cefotaxime acid mother liquor is concentrated by a nanofiltration membrane to obtain a cefotaxime acid mother liquor concentrate, and then cefotaxime acid is crystallized by adjusting the pH with hydrochloric acid. The nanofiltration equipment is usually expensive, has narrow applicability, and the nanofiltration membrane needs to be replaced regularly, so the industrialization cost is high.

[0006] In the technical solutions disclosed in patent documents CN106083895B (a method for purifying and recovering cefotaxime acid from cefotaxime sodium) and CN114349768B (a method for preparing cefotaxime acid), the starting raw materials are all unqualified cefotaxime sodium, and cefotaxime acid is obtained by dissolving and adjusting the crystallization pH. In the CN106083895B file, a crystallization solvent (acetone, methanol, ethanol or isopropanol) is added to the cefotaxime sodium solution, and then the pH value is adjusted for crystallization, and the crystallization process is carried out in a segmented manner. In the CN 114349768B file, it is necessary to add crystal seeds during the crystallization by adjusting the pH, and the crystal growing process also adopts a segmented manner. The methods in the above two files are used to reclaim or prepare cefotaxime acid, but there are problems such as small crystal particles, poor dispersibility, and difficulty in post-processing. Summary of the Invention

[0007] The present invention aims to provide a method for recovering cefotaxime acid from a ceftriaxone sodium mother liquor. The recovery method can effectively recover cefotaxime from the ceftriaxone sodium mother liquor, reduce resource waste, save production costs, facilitate organic solvent recovery, and reduce the chemical oxygen demand (COD) of the discharged waste liquid.

[0008] The present invention is achieved in that:

[0009] Provided is a method for recovering cefotaxime acid from a cefotaxime sodium mother liquor, comprising the following steps:

[0010] S1. vacuum concentrating the ceftriaxone sodium mother liquor to obtain a concentrated mother liquor;

[0011] S2, adjusting the pH of the concentrated mother liquor obtained in step S1 with an acid solution, and then mixing the concentrated mother liquor and water in a microporous mixer to obtain a mixed solution;

[0012] S3, the mixed solution obtained in step S2 is allowed to stand and then separated to obtain an aqueous phase, a decolorant or a filter aid or a mixture of the two is added to the aqueous phase, stirred and then filtered to obtain a filtrate, the decolorant and / or filter aid is washed with water, and the resultant mixture is combined with the filtrate;

[0013] S4, adding the filtrate obtained in step S3 and the acid solution to the dispersant simultaneously, and precipitating crystals under acidic conditions;

[0014] S5. Adjusting the pH to grow crystals, filtering to obtain crystals after growing the crystals, washing and drying to obtain the cefotaxime acid product.

[0015] Furthermore, in step S1, the temperature of the feed liquid during vacuum concentration is 10°C to 30°C; and the volume ratio of the cefotaxime sodium mother liquor to the concentrated mother liquor is 1:(0.2-0.3).

[0016] Further, in step S2, the mixing method of the concentrated mother liquor and water in the microporous mixer is as follows: the concentrated mother liquor and water are respectively injected into the microporous mixer for mixing, wherein the water is injected into the microporous mixer through micropores, and the concentrated mother liquor is injected into the microporous mixer through a main pipe; or the concentrated mother liquor is circulated by itself through the microporous mixer, and the water is injected into the circulating system through micropores.

[0017] Further, in steps S2-S4, the temperature is controlled at 5-10 DEG C.

[0018] Further, in step S2, the acid solution is hydrochloric acid, the pH value is adjusted to 5.5-6.8 by using hydrochloric acid, and the volume of water added is 20%-30% of the volume of the concentrated mother liquor.

[0019] Further, in step S3, the standing time is 20-30 minutes, the decoloring agent is activated carbon, the filter aid is diatomite, the stirring time is 30-40 minutes, and vacuum degassing is performed during the stirring process.

[0020] Further, in step S4, the dispersing agent is one or a mixture of two or more of acetonitrile, ethanol, n-propanol, isopropanol, n-butanol and dichloromethane, and the volume ratio of the water phase to the dispersing agent is 1:(0.1-0.3).

[0021] Further, in step S4, the acid solution is hydrochloric acid, the acid condition is that the pH value is 2.5-3.5, the filter liquor and the acid solution are simultaneously added to the dispersing agent in 30-60 minutes, and the crystal growing time is 20-30 minutes.

[0022] Further, in step S5, the pH value is adjusted to 2.5-3.0, the crystal growing time is 20-30 minutes, the washing method is that the crystal is sequentially washed with water, a mixed solution and an alcohol reagent, and the mixed solution is a mixed solution of water, the alcohol reagent and ethyl acetate in a volume ratio of 1:1:1.

[0023] Further, in step S5, the dried cefotaxime acid has a weight loss of 5%-10%.

[0024] The present application has the following beneficial effects:

[0025] In the present application, the organic phase (concentrated mother liquor of cefotaxime sodium) is mixed with the water phase by using the microporous mixer, the two phases are more fully contacted, the content of the effective component (cefotaxime) in the separated water phase is high, and the recovery rate of the product cefotaxime acid can be significantly improved.

[0026] The crystallization process of the present application is that the filtrate and acid are added into the dispersant at the same time, and the high supersaturation can be achieved at the initial stage of adding the crystallization system, so that the crystal out rate is fast, the particle is large, and the solid-liquid separation of the crystallization liquid is more favorable. The crystal growing system is a mixed crystallization system composed of water and the dispersant, and the solubility of the impurities is increased in the system, so that the mass of the obtained cefotaxime acid is good, and the yield is high.

[0027] The crystal is washed with water, mixed washing liquid and alcohol washing liquid in sequence in the present application, the inorganic salt and inorganic impurities in water can be removed by water, the organic impurities can be removed by the alcohol reagent, and the mass of the cefotaxime acid is improved.

[0028] The method for recovering cefotaxime acid from cefotaxime sodium mother liquor in the present application has simple operation steps and low cost, the effective component cefotaxime in the mother liquor can be recovered, the solvent is easy to recover, the COD of the waste liquid is reduced, and good economic benefit and social benefit are obtained. DETAILED DESCRIPTION

[0029] The present application is further described below in combination with the comparative examples and the examples, and the following implementation is only for illustration, and does not limit the protection scope of the present application in any form.

[0030] The processes and methods not described in detail in the following examples are the conventional methods known in the art, the reagents used in the examples are all analytical pure or chemical pure, and can be purchased or prepared by the methods well known to those skilled in the art. The following examples all achieve the purpose of the present application.

[0031] The cefotaxime sodium mother liquor contains cefotaxime, methanol, acetone, sodium acetate, ethyl acetate and other components in production. In the examples, the cefotaxime sodium mother liquor is simulated by combining the cefotaxime sodium production process: 500 g of cefotaxime acid is taken, 65 mL of purified water, 1450 mL of methanol, 500 mL of acetone, 100 g of sodium acetate is added, the temperature is controlled at 3 ℃, and the solution is stirred and dissolved to be clear. 1500 mL of ethyl acetate is added, the temperature is controlled at 3 ℃, the crystal is grown for 60 min, then 7000 mL of ethyl acetate is added, the crystal is grown for 30 min, the crystallization liquid is filtered, and the obtained mother liquor has a cefotaxime concentration of 4.26 mg / mL, which is used for subsequent mother liquor recovery experiment.

[0032] Example 1

[0033] Take cefotaxime sodium mother liquor 1000 mL, vacuum rotary evaporation to obtain 200 mL concentrated mother liquor (temperature of the feed liquid 10 °C). Temperature control 10 °C, with hydrochloric acid to adjust the pH of the concentrated mother liquor to 5.5, then the concentrated mother liquor through the micro-hole mixer for self-circulation, while 60 mL purified water through the micro-hole injection micro-hole mixer cavity, mixed after completion (i.e. purified water completely added to the self-circulation system) for 30 minutes, the mixture was transferred to the phase separation equipment, separation to obtain the aqueous phase, complete the extraction of the active ingredient cefotaxime; the aqueous phase was added 2 g of activated carbon, stirring for 40 minutes, vacuum degassing during stirring, filtration to obtain the filtrate. After decarbonization, the carbon cake was washed with 5 mL of purified water, and the filtrate was combined.

[0034] When crystallization, the obtained filtrate and hydrochloric acid were added into 6.5 mL acetonitrile at a time of 30 minutes, the process was controlled at 5 °C, and the pH value was maintained at 2.5-3.5; then the pH value was accurately adjusted to 2.6, and the crystal was aged for 20 minutes; after aging, the crystal was filtered to obtain the crystal, which was sequentially washed with water (7 mL), water (2.3 mL), ethanol (2.3 mL), ethyl acetate (2.3 mL) mixed washing liquid, and ethanol (7 mL). Vacuum drying at 30 °C until the product was qualified. Cefotaxime acid 3.55 g was obtained, with a yield of 83.3%, and the drying weight loss was 6.6%.

[0035] Example 2

[0036] Take cefotaxime sodium mother liquor 1000 mL, vacuum rotary evaporation to obtain 300 mL concentrated mother liquor (temperature of the feed liquid 20 °C). Temperature control 10 °C, with hydrochloric acid to adjust the pH of the concentrated mother liquor to 6.8, the concentrated mother liquor through the micro-hole mixer for self-circulation, while 60 mL purified water through the micro-hole injection micro-hole mixer cavity, mixed after completion for 20 minutes, the mixture was transferred to the phase separation equipment, separation to obtain the aqueous phase; the aqueous phase was added 3 g of diatomite, stirred for 30 minutes, vacuum degassing during stirring, filtration to obtain the filtrate. After desilication, the diatomite layer was washed with 5 mL of purified water, and the filtrate was combined.

[0037] The obtained filtrate and hydrochloric acid were added into 19.5 mL ethanol at a time of 40 minutes, the process was controlled at 10 °C, and the pH value was maintained at 2.5-3.5; then the pH value was accurately adjusted to 3.0, and the crystal was aged for 30 minutes; after aging, the crystal was filtered to obtain the crystal, which was sequentially washed with water (17 mL), water (5.7 mL), ethanol (5.7 mL), ethyl acetate (5.7 mL) mixed washing liquid, and ethanol (17 mL). Vacuum drying at 30 °C until the product was qualified. Cefotaxime acid 3.36 g was obtained, with a yield of 78.9%, and the drying weight loss was 7.2%.

[0038] Example 3

[0039] Take cefotaxime sodium mother liquor 1000 mL, vacuum rotary evaporation to obtain 220 mL concentrated mother liquor (temperature of feed liquid 30 °C). Control temperature 8 °C, adjust the pH value of concentrated mother liquor to 6.0 with hydrochloric acid, concentrated mother liquor directly into the micro-pore mixer (not for self-circulation), while 55 mL purified water through the micro-pore injection into the micro-pore mixer cavity, after mixing complete, stand for 30 minutes, the mixed solution is transferred to the phase separation equipment, separated to obtain the water phase; Add 1 g activated carbon, 2 grams of diatomite in the water phase, stirring for 30 minutes, vacuum degassing during stirring, filtration to obtain the filtrate. After removing carbon, diatomite, wash the carbon cake, diatomite layer with 5 mL purified water, combined with the filtrate.

[0040] The obtained filtrate and hydrochloric acid are simultaneously added into 12 mL isopropyl alcohol, the time is 40 minutes, the process control temperature is 8 °C, and the pH value is maintained at 2.5-3.5; then the pH value is accurately adjusted to 2.5, and the crystal is aged for 30 minutes; after aging, the crystal is filtered, and the crystal is sequentially washed with water (10 mL), water (3.3 mL), isopropyl alcohol (3.3 mL), ethyl acetate (3.3 mL) mixed washing liquid and isopropyl alcohol (10 mL). Vacuum drying at 30 °C until the product is qualified. Cefotaxime acid 3.48 g is obtained, the yield is 81.7%, and the drying loss is 6.9%.

[0041] Example 4

[0042] Take cefotaxime sodium mother liquor 1000 mL, vacuum rotary evaporation to obtain 250 mL concentrated mother liquor (temperature of feed liquid 30 °C). Control temperature 8 °C, adjust the pH value of concentrated mother liquor to 6.5 with hydrochloric acid, concentrated mother liquor through the micro-pore mixer for self-circulation, 55 mL purified water through the micro-pore injection into the micro-pore mixer cavity, after mixing complete, stand for 20 minutes, the mixed solution is transferred to the phase separation equipment, separated to obtain the water phase; Add 2 g activated carbon in the water phase, stirring for 40 minutes, vacuum degassing during stirring, filtration to obtain the filtrate, after removing carbon, wash the carbon cake with 5 mL purified water, combined with the filtrate.

[0043] The obtained filtrate and hydrochloric acid are simultaneously added into acetonitrile (2.5 mL), ethanol (2.5 mL) and dichloromethane (1 mL) mixed liquid, the time is 60 minutes, the process control temperature is 10 °C, and the pH value is maintained at 2.5-3.5; then the pH value is accurately adjusted to 2.5, and the crystal is aged for 30 minutes; after aging, the crystal is filtered, and the crystal is sequentially washed with water (12 mL), water (4 mL), ethanol (4 mL), ethyl acetate (4 mL) mixed washing liquid and ethanol (12 mL). Vacuum drying at 30 °C until the product is qualified. Cefotaxime acid 3.44 g is obtained, the yield is 80.8%, and the drying loss is 6.4%.

[0044] The quality comparison of cefotaxime acid products obtained in examples 1-4 and commercially available cefotaxime acid products is shown in table 1. As shown in table 1, the cefotaxime acid products recovered in examples 1-4 have high quality, and are equivalent to commercially available cefotaxime acid products.

[0045] Table 1 Comparison of the quality of cefotaxime acid products of Examples 1-4 with commercially available cefotaxime acid products

[0046]

[0047] Comparative Example 1

[0048] Take 1000 mL of cefotaxime sodium mother liquor, and vacuum rotary evaporation to obtain 250 mL of concentrated mother liquor (feed temperature 30°C). Control the temperature at 7°C, and adjust the pH of the concentrated mother liquor to 6.5 with hydrochloric acid. Directly add 55 mL of purified water to the concentrated mother liquor, stir for 20 minutes, and separate the water phase after standing for 20 minutes. Add 2 g of activated carbon to the water phase, stir for 40 minutes, vacuum degas during the stirring process, filter to obtain the filtrate, and wash the carbon cake with 5 mL of purified water after decarburization, and combine with the filtrate.

[0049] During crystallization, the obtained filtrate and hydrochloric acid are simultaneously added to a mixture of acetonitrile (2.5 mL), ethanol (2.5 mL), and dichloromethane (1 mL), and the process is controlled at a temperature of 10°C for 60 minutes, with the pH maintained at 2.5-3.5. Then, the pH is accurately adjusted to 2.5, and the crystals are aged for 30 minutes. After aging, the crystals are filtered, and sequentially washed with a mixture of water (12 mL), water (4 mL), ethanol (4 mL), ethyl acetate (4 mL), and ethanol (12 mL). Vacuum drying at 30°C until the product is qualified. Cefotaxime acid 3.10 g is obtained, with a yield of 72.8%, and a drying weight loss of 7.1%.

[0050] Comparative Example 1 uses the conventional two-phase mixing method to mix the concentrated mother liquor and water, i.e., without using a microporous mixer for two-phase mixing. The extraction effect of the water phase on the effective ingredient cefotaxime in Examples 1-4 and Comparative Example 1 is compared in Table 2.

[0051] The results show that using a microporous mixer to mix the organic phase and water can make the two phases more fully contact, the transfer rate of cefotaxime to the water phase is higher, i.e., the extraction rate of the water phase on the effective ingredient is higher, and the final product yield is higher.

[0052] Table 2 Comparison of the extraction effect of cefotaxime in Examples 1-4 and Comparative Example 1

[0053]

[0054] Comparative Example 2

[0055] Take cefotaxime sodium mother liquor 1000 mL, vacuum rotary evaporation to obtain 250 mL concentrated mother liquor (temperature of the feed liquid 30 °C). Control temperature 7 °C, with hydrochloric acid to adjust the pH of the concentrated mother liquor to 6.5, the concentrated mother liquor through the micro-hole mixer for self-circulation, 55 mL purified water through the micro-hole injection micro-hole mixer cavity, after mixing complete, stand for 20 minutes, the mixture is transferred to the phase separation equipment, separated to obtain the aqueous phase; the aqueous phase was added 2 g activated carbon, stirring 40 minutes, vacuum degassing during stirring, filtration to obtain the filtrate, after decarburization with 5 mL purified water to wash the carbon cake, combined with the filtrate.

[0056] When crystallization, to the resulting filtrate was added acetonitrile (2.5 mL), ethanol (2.5 mL), dichloromethane (1 mL) mixture, process control temperature 10 °C, with hydrochloric acid to adjust the pH to 2.5, then 30 minutes; after the crystal, filtration to obtain the crystal, in turn with water (12 mL), water (4 mL), ethanol (4 mL), ethyl acetate (4 mL) mixed washing liquid, ethanol (12 mL) to wash the crystal. 30 °C under vacuum drying to product qualified. Cefotaxime acid 3.35 g, yield 78.64 %, drying loss 9.1 %.

[0057] Comparative example 3

[0058] Take cefotaxime sodium mother liquor 1000 mL, vacuum rotary evaporation to obtain 250 mL concentrated mother liquor (temperature of the feed liquid 30 °C). Control temperature 7 °C, with hydrochloric acid to adjust the pH of the concentrated mother liquor to 6.5, the concentrated mother liquor through the micro-hole mixer for self-circulation, 55 mL purified water through the micro-hole injection micro-hole mixer cavity, after mixing complete, stand for 20 minutes, the mixture is transferred to the phase separation equipment, separated to obtain the aqueous phase; the aqueous phase was added 2 g activated carbon, stirring 40 minutes, vacuum degassing during stirring, filtration to obtain the filtrate, after decarburization with 5 mL purified water to wash the carbon cake, combined with the filtrate.

[0059] When crystallization, to the resulting filtrate was added acetonitrile (2.5 mL), ethanol (2.5 mL), dichloromethane (1 mL) mixture, process control temperature 10 °C, with hydrochloric acid to adjust the pH to 2.5, then 30 minutes; after the crystal, filtration to obtain the crystal, in turn with water (12 mL), water (4 mL), ethanol (4 mL), ethyl acetate (4 mL) mixed washing liquid, ethanol (12 mL) to wash the crystal. 30 °C under vacuum drying to product qualified. Cefotaxime acid 3.35 g, yield 78.64 %, drying loss 9.1 %.

[0060] The crystallization process in Comparative Example 2 is to add the dispersant (acetonitrile, ethanol, isopropanol or mixed solution thereof) and hydrochloric acid into the filtrate in sequence, and the crystal is precipitated by changing the pH, the obtained crystal particles are small and the particle size is not uniform, the crystal particle bulk density is large, and the dispersibility is poor. In Comparative Example 3, the dispersant and hydrochloric acid are added into the filtrate at the same time, and the pH cannot be maintained in the crystallization range quickly during the addition process, and the crystallization effect is not ideal. The crystallization effect comparison of Examples 1-4 and Comparative Examples 2-3 is shown in Table 3.

[0061] Table 3 Crystallization effect comparison of Examples 1-4 and Comparative Examples 2-3

[0062]

[0063]

[0064] The cefotaxime acid product recovered from the cefotaxime sodium mother liquor according to the present application meets the industry quality standard, and the quality is at the same level as that of the commercially available cefotaxime acid product. In the preparation process, the effective component cefotaxime in the concentrated mother liquor is subjected to liquid-liquid extraction by using a microporous mixer, and the water phase containing cefotaxime and hydrochloric acid are added into the dispersant at the same time, which can effectively improve the crystallization state, and finally realize the efficient recovery of the effective component cefotaxime in the cefotaxime sodium mother liquor.

Claims

1. A method for recovering cefotaxime acid from a cefotaxime sodium mother liquor, characterized in that: The following steps are involved: S1. vacuum concentrating the ceftriaxone sodium mother liquor to obtain a concentrated mother liquor; S2, adjusting the pH of the concentrated mother liquor obtained in step S1 with an acid solution, and then mixing the concentrated mother liquor and water in a microporous mixer to obtain a mixed solution; S3, the mixed solution obtained in step S2 is allowed to stand and then separated to obtain an aqueous phase, a decolorant or a filter aid or a mixture of the two is added to the aqueous phase, stirred and then filtered to obtain a filtrate, the decolorant and / or filter aid is washed with water, and the resultant mixture is combined with the filtrate; S4, adding the filtrate obtained in step S3 and the acid solution to the dispersant simultaneously, and precipitating crystals under acidic conditions; S5. Adjusting the pH to grow crystals, filtering to obtain crystals after growing the crystals, washing and drying to obtain the cefotaxime acid product.

2. The method for recovering cefotaxime acid from cefotaxime sodium mother liquor according to claim 1, wherein In step S1, the temperature of the feed liquid during vacuum concentration is 10° C. to 30° C.; and the volume ratio of the cefotaxime sodium mother liquor to the concentrated mother liquor is 1:(0.2 to 0.3).

3. The method for recovering cefotaxime acid from cefotaxime sodium mother liquor according to claim 1, wherein In step S2, the concentrated mother liquor and water are mixed in the microporous mixer by injecting the concentrated mother liquor and water into the microporous mixer separately for mixing; or the concentrated mother liquor is self-circulated through the microporous mixer, and water is injected into the microporous mixer through the micropores to enter the circulation system.

4. The method for recovering cefotaxime acid from cefotaxime sodium mother liquor according to claim 1, wherein In steps S2 to S4, the temperature is controlled at 5 to 10°C.

5. The method for recovering cefotaxime acid from cefotaxime sodium mother liquor according to claim 1, wherein: In step S2, the acid solution is hydrochloric acid, and the pH value is adjusted to 5.5-6.8 with hydrochloric acid; the volume of water added is 20%-30% of the volume of the concentrated mother liquor.

6. The method for recovering cefotaxime acid from cefotaxime sodium mother liquor according to claim 1, wherein In step S3, the standing time is 20 to 30 minutes; the decolorizing agent is activated carbon, and the filter aid is diatomaceous earth; the stirring time is 30 to 40 minutes, and vacuum degassing is performed during the stirring process.

7. The method for recovering cefotaxime acid from cefotaxime sodium mother liquor according to claim 1, wherein: In step S4, the dispersant is one or a mixed solution of two or more of acetonitrile, ethanol, n-propanol, isopropanol, n-butanol, and dichloromethane; and the volume ratio of the filtrate to the dispersant is 1:(0.1-0.3).

8. The method for recovering cefotaxime acid from cefotaxime sodium mother liquor according to claim 1, wherein: In step S4, the acid solution is hydrochloric acid, and the acidic condition is a pH of 2.5 to 3.5; the process of adding the filtrate and hydrochloric acid to the dispersant takes 30 to 60 minutes.

9. The method for recovering cefotaxime acid from cefotaxime sodium mother liquor according to claim 1, wherein In step S5, the pH value is adjusted to 2.5-3.0, and the crystal growing time is 20-30 minutes; the washing method is to wash the crystals with water, a mixed solution, and an alcohol reagent in sequence, and the mixed solution is a mixed solution of water, an alcohol reagent, and ethyl acetate in a volume ratio of 1:1:

1.

10. The method for recovering cefotaxime acid from cefotaxime sodium mother liquor according to claim 1, wherein In step S5, the drying loss of the obtained cefotaxime acid is 5% to 10%.

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