Method for recovering 7-amino-deacetoxycephalosporanic acid and D-p-hydroxyphenylglycine from cefadroxil crystallization mother liquor

Abstract

The present invention discloses a method for recovering 7-amino-desacetoxycephalosporanic acid and D-p-hydroxyphenylglycine from the crystallization mother liquor of cefadroxil. The method includes: hydrolysis of the crystallization mother liquor of cefadroxil; adsorption and desorption of the hydrolyzate by a macroporous adsorption resin column; the obtained 7-amino-desacetoxycephalosporanic acid desorption solution is adjusted to a pH of 3.0-4.5 with an acid solution, and 7-amino-desacetoxycephalosporanic acid crystallizes out; the obtained adsorption residual solution is concentrated by nanofiltration and adjusted in pH value to obtain D-p-hydroxyphenylglycine crystals. The method of the present invention has a reasonable process design, realizes the recovery of 7-ADCA and D-p-hydroxyphenylglycine at the same time, has a high recovery rate, excellent product quality and is environmentally friendly.

Description

Technical Field

[0001] The present invention belongs to the field of pharmaceutical technology and relates to a method for recovering 7-amino-desacetoxycephalosporanic acid (hereinafter referred to as 7-ADCA) and D-p-hydroxyphenylglycine from the crystallization mother liquor of cefadroxil. Background Art

[0002] Cefadroxil is a first-generation oral cephalosporin antibiotic, mainly used for respiratory tract infections caused by staphylococcus, streptococcus, pneumococcus, Escherichia coli, etc., such as pneumonia, acute tracheobronchitis, pharyngitis, tonsillitis, sinusitis, etc.; it can also be used for skin and soft tissue infections, such as cellulitis, etc.; it can also be used for urinary tract infections caused by the above-mentioned sensitive bacteria, such as acute cystitis, prostatitis, acute pyelonephritis, etc. The structural formula of cefadroxil is as follows:

[0003]

[0004] At present, the production method of cefadroxil is to synthesize with 7-amino-desacetoxycephalosporanic acid and D-p-hydroxyphenylglycine methyl ester hydrochloride as raw materials under the action of immobilized penicillin acylase. Among them, in the literature "Research on the Fermentation of Penicillin Acylase and the Enzymatic Synthesis of Cefadroxil" (Liu Danjun, Central South University of Forestry and Technology, 2016), it is mentioned that the optimal molar ratio of 7-amino-desacetoxycephalosporanic acid and D-p-hydroxyphenylglycine methyl ester hydrochloride is 1:1.2. Therefore, a large amount of cefadroxil and D-p-hydroxyphenylglycine remain in the crystallization mother liquor of enzymatic production of cefadroxil. In order to recover these active ingredients in the crystallization mother liquor of cefadroxil, scientific research personnel have done a lot of work.

[0005] Chinese patent document CN201611201775.0 "A Method for Enzymatic Synthesis of Cefadroxil" proposes a method for preparing cefadroxil and recovering cefadroxil from the crystallization mother liquor of cefadroxil, that is, adding β-naphthol or 2,7-dihydroxynaphthalene to the crystallization mother liquor of cefadroxil to form a complex of cefadroxil and precipitate, achieving the effect of recovering cefadroxil from the crystallization mother liquor of cefadroxil. Although this method can directly recover cefadroxil in the mother liquor, the introduction of β-naphthol or 2,7-dihydroxynaphthalene not only increases the recovery cost, but also increases the discharge of organic waste, which does not meet the requirements of green production.

[0006] Chinese patent document CN202111004849.2, "A method for recovering 7-ADCA", proposes a method for recovering 7-ADCA from the cephalexin crystalline mother liquor. That is, after hydrolyzing cephalexin in the cephalexin crystalline mother liquor into 7-ADCA and D-p-hydroxyphenylglycine with a hydrolase, 7-ADCA in it is crystallized out by adjusting the pH of the feed liquid to 5.0 - 6.0, so as to achieve the purpose of recovering 7-ADCA. Although this method achieves the purpose of recovering 7-ADCA from the mother liquor, the recovery rate is low. At the same time, a large amount of D-p-hydroxyphenylglycine in the crystallization liquid results in poor quality of the recovered 7-ADCA, unable to achieve the effect of reuse, and the recovery and utilization of D-p-hydroxyphenylglycine are not considered.

[0007] Therefore, it is necessary to conduct in-depth research on the recovery process of 7-aminocephalosporanic acid and D-p-hydroxyphenylglycine in the cephalexin crystalline mother liquor, so as to effectively recover high-quality 7-aminocephalosporanic acid and D-p-hydroxyphenylglycine from the cephalexin crystalline mother liquor simultaneously. Summary of the Invention

[0008] Technical Problem

[0009] In view of the above problems in the prior art, the inventor of the present invention has conducted in-depth research on the recovery process of 7-aminocephalosporanic acid and D-p-hydroxyphenylglycine in the cephalexin crystalline mother liquor, thus completing the present invention. The purpose of the present invention is to provide a method for recovering 7-aminocephalosporanic acid and D-p-hydroxyphenylglycine from the cephalexin crystalline mother liquor. This method has a reasonable process design, realizes the recovery of 7-ADCA and D-p-hydroxyphenylglycine simultaneously, has a high recovery rate, excellent product quality, and is environmentally friendly.

[0010] Technical Solution

[0011] According to the present invention, the method for recovering 7-aminocephalosporanic acid and D-p-hydroxyphenylglycine from the cephalexin crystalline mother liquor provided by the present invention includes the following steps:

[0012] Step 1: After the enzyme method-produced cephalexin crystalline mother liquor is separated from the cephalexin crystals, the pH of the mother liquor is adjusted to 7.5 - 8.5 with an alkali solution, and then a hydrolysis reaction is carried out in the presence of an immobilized hydrolase. After the hydrolysis is completed, the immobilized hydrolase is separated to obtain the hydrolysis solution of the cephalexin crystalline mother liquor.

[0013] Step 2: After adjusting the pH of the hydrolysis solution of the cefadroxil crystalline mother liquor obtained in Step 1 above to 6.0 - 7.0 with an acid solution, adsorb it with macroporous adsorption resin. Among them, 7-amino-deacetoxycephalosporanic acid in the hydrolysis solution is adsorbed on the resin, and D-p-hydroxyphenylglycine in the hydrolysis solution flows through the resin and is collected as the adsorption residue solution; after the adsorption is completed, elute 7-amino-deacetoxycephalosporanic acid adsorbed on the resin with an eluent to obtain an elution solution of 7-amino-deacetoxycephalosporanic acid;

[0014] Step 3: Control the temperature of the elution solution of 7-amino-deacetoxycephalosporanic acid obtained in Step 2 above at 10°C - 15°C, decolorize with activated carbon, and then adjust the pH to 3.0 - 4.5 with an acid solution. 7-Amino-deacetoxycephalosporanic acid crystallizes out, and then cool down to 5°C - 10°C for crystal growth. After filtration and drying, 7-amino-deacetoxycephalosporanic acid crystals are obtained;

[0015] Step 4: Adjust the pH of the adsorption residue solution obtained in Step 2 to 9.0 - 9.5 with an alkali, and then perform nanofiltration concentration using a nanofiltration membrane to obtain a concentrated solution of D-p-hydroxyphenylglycine; then at 35°C - 45°C, adjust the pH value of the concentrated solution of D-p-hydroxyphenylglycine to 4.5 - 5.5 with hydrochloric acid, and D-p-hydroxyphenylglycine crystals gradually precipitate. Then cool down to 5°C - 10°C for crystal growth. After filtration and drying, D-p-hydroxyphenylglycine crystals are obtained.

[0016] The method for recovering 7-amino-deacetoxycephalosporanic acid and D-p-hydroxyphenylglycine from cefadroxil crystalline mother liquor of the present invention is described in more detail below.

[0017] Figure 1 is the process flow chart of the method for recovering 7-amino-deacetoxycephalosporanic acid and D-p-hydroxyphenylglycine from cefadroxil crystalline mother liquor of the present invention. As Figure 1 shown, in Step 1, after the enzymatic production of cefadroxil crystalline mother liquor is separated from cefadroxil crystals, adjust the pH of the mother liquor to 7.5 - 8.5 with an alkali solution, and then carry out a hydrolysis reaction in the presence of immobilized hydrolase. After the hydrolysis is completed, separate the immobilized hydrolase to obtain the hydrolysis solution of cefadroxil crystalline mother liquor.

[0018] Under the action of immobilized penicillin acylase, 7-aminocephalosporanic acid and methyl D-p-hydroxyphenylglycinate are condensed to produce cefadroxil. After separating the cefadroxil crystals, the mother liquor for the enzymatic production of cefadroxil crystals is obtained. The concentration of cefadroxil in the mother liquor is about 10 - 25 g / L, the concentration of 7-aminocephalosporanic acid is about 1 - 5 g / L, the concentration of D-p-hydroxyphenylglycine is about 5 - 15 g / L, the concentration of methyl D-p-hydroxyphenylglycinate is about 0 - 1 g / L, the pH range of the mother liquor is 5.0 - 6.0, and the temperature range is 0°C - 20°C.

[0019] In order to fully and effectively recover 7-aminocephalosporanic acid and D-p-hydroxyphenylglycine in the cefadroxil crystal mother liquor, the cefadroxil in the mother liquor needs to be hydrolyzed. The method used in the present invention is enzymatic hydrolysis, that is, immobilized penicillin acylase is used to hydrolyze cefadroxil to obtain 7-aminocephalosporanic acid and D-p-hydroxyphenylglycine. Under the action of immobilized penicillin acylase, 7-aminocephalosporanic acid and methyl D-p-hydroxyphenylglycinate are condensed to produce cefadroxil. This is a reversible reaction. Condensation is favored under slightly acidic conditions, while hydrolysis is favored under slightly alkaline conditions. Therefore, the pH of the mother liquor is adjusted, that is, an alkaline solution is used to adjust the pH of the mother liquor to 7.5 - 8.5. The alkaline solution is sodium hydroxide solution or ammonia water. At the same time, the residual methyl D-p-hydroxyphenylglycinate in the mother liquor can also be hydrolyzed to produce D-p-hydroxyphenylglycine.

[0020] The immobilized penicillin acylase is a commercial product and can be obtained by purchase. An intermittent enzyme reactor is used. During the reaction process, the cefadroxil crystal mother liquor and the immobilized penicillin acylase are mixed, and the pH of the feed liquid is maintained in the range of 7.5 - 8.5 and the temperature range is 5°C - 10°C under stirring for the reaction. The residual concentration of cefadroxil is detected by high performance liquid chromatography during the reaction process. When the reaction reaches a cefadroxil concentration below 0.5 g / L, the reaction ends, and enzyme separation is carried out. The immobilized enzyme particles are retained on the filter screen, and the hydrolysis solution of the cefadroxil crystal mother liquor is obtained after the feed liquid passes through the screen.

[0021] The composition of the hydrolysis solution of the obtained cefadroxil crystal mother liquor is generally: the concentration of 7-aminocephalosporanic acid is about 8 - 22 g / L, the concentration of D-p-hydroxyphenylglycine is about 10 - 30 g / L, the pH range of the hydrolysis solution is 7.5 - 8.5, and the temperature range is 5°C - 10°C.

[0022] In step 2, after adjusting the pH of the hydrolysis solution of the cefadroxil crystallization mother liquor obtained in step 1 to 6.0 - 7.0 with an acid solution, it is adsorbed with a macroporous adsorption resin. Among them, 7 - amino - deacetoxycephalosporanic acid in the hydrolysis solution is adsorbed on the resin, and D - p - hydroxyphenylglycine in the hydrolysis solution passes through the resin and is collected as the adsorption residue solution; after adsorption, the 7 - amino - deacetoxycephalosporanic acid adsorbed on the resin is desorbed with a desorbent to obtain a 7 - amino - deacetoxycephalosporanic acid desorption solution.

[0023] In step (2), the separation of 7 - amino - deacetoxycephalosporanic acid and D - p - hydroxyphenylglycine is achieved. Among them, 7 - amino - deacetoxycephalosporanic acid is adsorbed on the resin and a 7 - amino - deacetoxycephalosporanic acid desorption solution is obtained through desorption, while D - p - hydroxyphenylglycine passes through the resin and is in the adsorption residue solution. To improve the adsorption efficiency, the pH of the hydrolysis solution needs to be adjusted to 6.0 - 7.0 before adsorption, preferably 6.0 - 6.8. For example, acid solutions such as hydrochloric acid, sulfuric acid, and nitric acid can be used for adjustment. Subsequently, it is adsorbed with a resin column. Among them, the macroporous adsorption resin can be selected as a macroporous adsorption resin with a pore size of 5 - 30 nanometers, a skeletal structure of styrene - divinylbenzene series, and a specific surface area of greater than 1100 square meters / g. In the method of the present invention, for example, LXT - 036 model, LXT - 043 model, and LXT - 095 model produced by Xi'an BlueSail New Materials Co., Ltd. can be used.

[0024] The macroporous adsorption resin is applied in the form of a circular resin column bed through wet packing, and the ratio of the height to the diameter of the circular resin column bed (i.e., the height - to - diameter ratio) is 4 or greater, preferably greater than or equal to 8, and more preferably greater than or equal to 16.

[0025] The adsorption capacity of the macroporous adsorption resin for 7 - amino - deacetoxycephalosporanic acid is related to the concentration of 7 - amino - deacetoxycephalosporanic acid in the hydrolysis solution and the characteristics of the resin. In a specific embodiment, the hydrolysis solution obtained in step 1 above is passed through the macroporous adsorption resin column at a certain flow rate. This hydrolysis solution preferably passes through the resin column bed at a flow rate of 1 - 3 times the total volume of the resin per hour. When 7 - amino - deacetoxycephalosporanic acid is detected at the lower - end outlet of the column bed, the feeding of the hydrolysis solution onto the column is stopped. In a preferred embodiment, at this time, before desorption, the resin can be washed with 1.0 - 2.0 times the total volume of the resin with water to wash out the residual hydrolysis solution in the resin column bed, and this part of the collected top - wash solution is incorporated into the adsorption residue solution.

[0026] 7-Amino desacetoxycephalosporanic acid in the hydrolyzate is adsorbed onto the resin, and a desorbent is used to desorb the 7-amino desacetoxycephalosporanic acid adsorbed on the resin. The desorbent can be a weak acid salt solution, such as sodium acetate, sodium carbonate or sodium bicarbonate solution, and sodium bicarbonate solution is most preferred. The concentration of the sodium bicarbonate solution is preferably between 2.0 and 8.0 wt%, more preferably between 4.0 and 6.0 wt%. The flow rate of the desorbent is 1.0 to 3.0 times the total volume of the resin per hour, preferably 1.5 times the total volume of the resin per hour. After the desorption starts, the effluent desorbent is collected in fractions, and the concentration of 7-amino desacetoxycephalosporanic acid in the desorbent is detected by high performance liquid chromatography. The desorbent with a 7-amino desacetoxycephalosporanic acid concentration higher than 20 g / L is used for the crystallization of 7-amino desacetoxycephalosporanic acid, and the part with a concentration lower than 20 g / L can be used as the desorbent for the next batch. In addition, in the fractional collection of the desorbent, the desorbent that does not contain 7-amino desacetoxycephalosporanic acid in the early stage can be combined into the adsorption residue liquid.

[0027] In the collected desorbent, the desorbents with a 7-amino desacetoxycephalosporanic acid concentration higher than 20 g / L are combined to obtain a high-concentration desorbent, in which the concentration of 7-amino desacetoxycephalosporanic acid is about 22 to 35 g / L, and the concentration of D-p-hydroxyphenylglycine is lower than 5 g / L. The temperature range is 10°C to 15°C. The desorption yield of 7-amino desacetoxycephalosporanic acid is greater than or equal to 95%.

[0028] In the collected adsorption residue liquid, the concentration of D-p-hydroxyphenylglycine is 10 to 30 g / L, and the concentration of 7-amino desacetoxycephalosporanic acid is lower than 1 g / L.

[0029] In step 3, the 7-amino desacetoxycephalosporanic acid desorbent obtained in step 2 above is controlled at a temperature of 10°C to 15°C, decolorized with activated carbon, and then the pH is adjusted to 3.0 to 4.5 with an acid solution. 7-Amino desacetoxycephalosporanic acid crystallizes out, and then the temperature is lowered to 5°C to 10°C for crystal growth. After filtration and drying, 7-amino desacetoxycephalosporanic acid crystals are obtained.

[0030] In step 3, the analytical solutions with a 7-aminocephalosporanic acid concentration higher than 20 g / L obtained in step 2 are combined to obtain a high-concentration analytical solution for the crystallization of 7-aminocephalosporanic acid. The temperature is controlled at 10°C to 15°C. After decolorization with activated carbon, the pH is adjusted to 3.0 to 4.5 with an acid solution. The acid solution is an acid solution such as hydrochloric acid, sulfuric acid, or nitric acid, and sulfuric acid solution is preferred. Specifically, during the crystallization process at 10°C to 15°C, first adjust the pH of the feed liquid to 6.5 to 7.0 with sulfuric acid. At this time, no solid precipitates in the system. Add activated carbon, stir for decolorization, and then filter to remove the activated carbon. Subsequently, continue to add sulfuric acid to adjust the pH value of the feed liquid. When the pH is about 6.3 to 6, crystals of 7-aminocephalosporanic acid begin to precipitate, which is the crystallization point. Crystal growth can be appropriately carried out, and then continue to adjust the pH value of the feed liquid to 3.0 to 4.5, preferably 3.5 to 4.0. Then cool down to 5°C to 10°C for crystal growth. After filtration and drying, crystals of 7-aminocephalosporanic acid are obtained.

[0031] In step 4, the pH of the adsorption residual liquid obtained in step 2 is adjusted to 9.0 to 9.5 with an alkali, and then nanofiltration concentration is carried out using a nanofiltration membrane to obtain a D-p-hydroxyphenylglycine concentrated solution; then at 35°C to 45°C, the pH value of this D-p-hydroxyphenylglycine concentrated solution is adjusted to 4.5 to 5.5 with hydrochloric acid, and D-p-hydroxyphenylglycine crystals gradually precipitate. Then cool down to 5°C to 10°C for crystal growth. After filtration and drying, D-p-hydroxyphenylglycine crystals are obtained.

[0032] Among them, in step 4, the alkali is an alkali solution such as sodium hydroxide solution, potassium hydroxide solution, or ammonia water, and sodium hydroxide solution is preferred; adjusting the pH to 9.0 to 9.5 can ensure that D-p-hydroxyphenylglycine does not precipitate during the concentration process.

[0033] For nanofiltration concentration using a nanofiltration membrane, a nanofiltration membrane with a molecular weight cut-off of 100 to 200 Da can be used, and more preferably a nanofiltration membrane with a molecular weight cut-off of 100 to 150 Da is used for nanofiltration concentration to obtain a D-p-hydroxyphenylglycine concentrated solution, in which the concentration of D-p-hydroxyphenylglycine is 60 to 70 g / L and the pH is 8.5 to 9.0. Then, at 35°C to 45°C, the pH value of this D-p-hydroxyphenylglycine concentrated solution is adjusted to 4.5 to 5.5, preferably 5.0 to 5.5, and D-p-hydroxyphenylglycine crystals gradually precipitate. Then cool down to 5°C to 10°C for crystal growth. After filtration and drying, D-p-hydroxyphenylglycine crystals are obtained.

[0034] Beneficial effects

[0035] The present invention realizes the separation of 7-aminodeacetoxycephalosporanic acid and D-p-hydroxyphenylglycine through the action of macroporous adsorption resin, not only achieving the purpose of separation, but also achieving the concentration effect of 7-aminodeacetoxycephalosporanic acid, which plays a key role in improving the product yield and quality.

[0036] The present invention adopts a nanofiltration membrane to perform nanofiltration concentration on the adsorption residue liquid containing D-p-hydroxyphenylglycine, which not only increases the concentration of D-p-hydroxyphenylglycine, further improving the recovery rate of D-p-hydroxyphenylglycine; but also reduces the salt concentration in the crystallization liquid, achieving the effect of increasing the content of D-p-hydroxyphenylglycine.

[0037] The preparation method of the present invention is simple and feasible, with mild conditions, safe and environmentally friendly, and suitable for industrial production. Brief Description of the Drawings

[0038] Figure 1 It is a process flow chart of the method for recovering 7-aminodeacetoxycephalosporanic acid and D-p-hydroxyphenylglycine from the cefadroxil crystallization mother liquor of the present invention. Detailed Description of the Invention

[0039] The following further details the method for recovering 7-aminodeacetoxycephalosporanic acid and D-p-hydroxyphenylglycine from the cefadroxil crystallization mother liquor of the present invention through examples. The protection scope of the present invention is not limited to the following examples, and these examples are listed only for illustrative purposes and do not limit the present invention in any way.

[0040] Example 1

[0041] (1) Hydrolysis of the cefadroxil crystallization mother liquor

[0042] Take 50 L of the enzymatic production cefadroxil crystallization mother liquor, with a pH of 5.4 and a temperature of 12 °C. Quantitatively detect the components of the mother liquor by high performance liquid chromatography. Among them, the cefadroxil concentration is about 19 g / L, the 7-aminodeacetoxycephalosporanic acid concentration is about 1.6 g / L, the D-p-hydroxyphenylglycine concentration is about 7 g / L, and the D-p-hydroxyphenylglycine methyl ester concentration is about 0.1 g / L.

[0043] Put the above mother liquor into an enzyme reaction tank equipped with immobilized penicillin acylase, start stirring, control the temperature in the tank at 5°C - 6°C, adjust the pH of the feed liquid to 7.9 with 20% sodium hydroxide solution, and after reacting for 30 min, detect the residue of cefadroxil by high-performance liquid chromatography to be 0.01 g / L. After the reaction is completed, open the bottom valve of the enzyme reaction tank, discharge the liquid in the tank, and wash the enzyme in the pipe with an appropriate amount of water to obtain 55 L of the hydrolysis solution of the cefadroxil crystal mother liquor. The pH of the hydrolysis solution is 7.9 and the temperature is 6°C. The components of the mother liquor are quantitatively detected by high-performance liquid chromatography. Among them, the concentration of cefadroxil is about 0.01 g / L, the concentration of 7-amino-desacetoxycephalosporanic acid is about 11.6 g / L, the concentration of D-p-hydroxyphenylglycine is about 14.3 g / L, and the concentration of D-p-hydroxyphenylglycine methyl ester is about 0 g / L.

[0044] (2) Adsorption and desorption of the hydrolysis solution by a macroporous adsorption resin column

[0045] Adjust the pH of the hydrolysis solution of the cefadroxil crystal mother liquor obtained in the above step (1) to 6.8 with 30% hydrochloric acid. Let the feed liquid pass through a macroporous resin adsorption column at a flow rate of 5.0 L per hour. The column is filled with 2.5 L of LXT-036 type resin, and the height-diameter ratio of the column is 5. The column is packed by the wet method. Collect the adsorption residual liquid flowing through the resin column. After the adsorption is completed, first wash the adsorption column with 2.5 L of water, and then use 4.0 wt% sodium bicarbonate solution as the desorbent to desorb at a flow rate of 3.5 L per hour. Collect the desorption solution in segments, and quantitatively detect the components of the desorption solution by high-performance liquid chromatography. Among them, the desorption solution without 7-amino-desacetoxycephalosporanic acid in the early stage is merged into the adsorption residual liquid, and those with a concentration higher than 20 g / L are merged into the decolorization tank of the 7-amino-desacetoxycephalosporanic acid desorption solution, and those with a concentration lower than 20 g / L are merged into the desorption solution storage tank and re-prepared for the next desorption. Specifically,

[0046] In this batch, a total of 65 L of adsorption residual liquid is obtained, and the concentration of D-p-hydroxyphenylglycine is about 11.5 g / L;

[0047] 20 L of the desorption solution with a concentration of 7-amino-desacetoxycephalosporanic acid higher than 20 g / L after merging, in which the concentration of 7-amino-desacetoxycephalosporanic acid is 28 g / L and the concentration of D-p-hydroxyphenylglycine is about 1.1 g / L. This part of the feed liquid is used for the preparation of 7-amino-desacetoxycephalosporanic acid;

[0048] 11 L of the desorption solution with a concentration of 7-amino-desacetoxycephalosporanic acid lower than 20 g / L after merging, in which the concentration of 7-amino-desacetoxycephalosporanic acid is 7 g / L and the concentration of D-p-hydroxyphenylglycine is about 0.7 g / L; this part of the feed liquid is preferentially used as the desorption solution for the next batch.

[0049] (3) Preparation of 7-amino-desacetoxycephalosporanic acid

[0050] After transferring the high-concentration analytical solution obtained in the above step (2) to the decolorization tank, start stirring and quickly adjust the pH to 6.8 with sulfuric acid, control the temperature at 10°C to 11°C, add activated carbon, decolorize for 30 minutes, filter to remove the activated carbon after decolorization is completed, transfer the filtrate to the crystallization tank, continue to adjust the pH of the feed liquid to 6.3 with sulfuric acid. At this time, solids start to precipitate in the system. Continue to add sulfuric acid dropwise and keep the pH of the feed liquid between 6.3 and 6.0. After the pH no longer changes, carry out crystal cultivation for 30 minutes. Then continue to add sulfuric acid to adjust the pH of the feed liquid to 3.8, carry out crystal cultivation for 60 minutes, then cool down to 5°C for crystal cultivation. After filtration and drying, 535 g of 7-amino deacetoxycephalosporanic acid solid is obtained, with a purity of 99.3%, D-p-hydroxyphenylglycine not detected, and the conversion yield is 83.6%.

[0051] (4) Preparation of D-p-hydroxyphenylglycine

[0052] Adjust the pH of the adsorption residual liquid obtained in the above step (2) to 9.3 with 32% sodium hydroxide solution, and then carry out nanofiltration concentration using a nanofiltration membrane with a cut-off molecular weight of 150 Dalton to obtain 12 L of D-p-hydroxyphenylglycine concentrated solution. After concentration, the concentration of D-p-hydroxyphenylglycine is about 62 g / L, and the temperature of the feed liquid rises to 45°C during the concentration process; after concentration is completed, transfer the concentrated solution to the crystallization tank, slowly and continuously add hydrochloric acid to the feed liquid until the pH value is 4.8, then cool down to 5°C for crystal cultivation. After filtration and drying, 700 g of D-p-hydroxyphenylglycine solid is obtained, with a content of 99.8%, and the conversion recovery rate is 88.5%.

[0053] Example 2

[0054] (1) Hydrolysis of cefadroxil crystallization mother liquor

[0055] Take 50 L of the crystallization mother liquor of cefadroxil produced by the enzymatic method, with a pH of 5.6 and a temperature of 17°C. Quantitatively detect the components of the mother liquor by high-performance liquid chromatography. Among them, the concentration of cefadroxil is about 25 g / L, the concentration of 7-amino deacetoxycephalosporanic acid is about 2.1 g / L, the concentration of D-p-hydroxyphenylglycine is about 9 g / L, and the concentration of D-p-hydroxyphenylglycine methyl ester is about 0.2 g / L.

[0056] Put the above mother liquor into an enzyme reaction tank equipped with immobilized penicillin acylase, start stirring, control the temperature in the tank at 9 - 10 °C, adjust the pH of the feed liquid to 8.5 with 30% sodium hydroxide solution. After reacting for 30 min, detect the residue of cefadroxil by high-performance liquid chromatography, and the residue is 0.01 g / L. After the reaction is completed, open the bottom valve of the enzyme reaction tank, discharge the liquid in the tank, and wash the enzyme in the pipe with an appropriate amount of water to obtain 53 L of hydrolysis solution of cefadroxil crystallization mother liquor. The pH of the hydrolysis solution is 8.4 and the temperature is 9 °C. The components of the mother liquor are quantitatively detected by high-performance liquid chromatography. The concentration of cefadroxil is about 0.01 g / L, the concentration of 7-amino-desacetoxycephalosporanic acid is about 15.8 g / L, the concentration of D-p-hydroxyphenylglycine is about 19.5 g / L, and the concentration of D-p-hydroxyphenylglycine methyl ester is about 0 g / L.

[0057] (2) Adsorption and desorption of the hydrolysis solution by macroporous adsorption resin column

[0058] Adjust the pH of the cefadroxil crystallization mother liquor hydrolysis solution obtained in the above step (1) to 6.8 with 30% hydrochloric acid. Let the feed liquid pass through a macroporous resin adsorption column at a flow rate of 5.0 L per hour. The column is filled with 2.5 L of LXT-095 type resin, and the height-diameter ratio of the column is 8. The column is packed by the wet method. Collect the adsorption residual liquid flowing through the resin column. After the adsorption is completed, first wash the adsorption column with 3 L of water, then elute it with the low-concentration desorption liquid of the previous batch (the low-concentration desorption liquid obtained in Example 1), and then use 6.0 wt% sodium bicarbonate solution as the desorbent to desorb at a flow rate of 3.8 L per hour. Collect the desorption liquid in segments, and quantitatively detect the components of the desorption liquid by high-performance liquid chromatography. Among them, the desorption liquid without 7-amino-desacetoxycephalosporanic acid in the early stage is merged into the adsorption residual liquid, the desorption liquid with a concentration higher than 20 g / L is merged into the 7-amino-desacetoxycephalosporanic acid decolorization tank, and the desorption liquid with a concentration lower than 20 g / L is merged into the desorption liquid storage tank and re-prepared for the next desorption. Specifically,

[0059] In this batch, a total of 63 L of adsorption residual liquid is obtained, and the concentration of D-p-hydroxyphenylglycine is about 15 g / L;

[0060] After merging, 24 L of desorption liquid with a concentration of 7-amino-desacetoxycephalosporanic acid higher than 20 g / L, in which the concentration of 7-amino-desacetoxycephalosporanic acid is 34 g / L, and the concentration of D-p-hydroxyphenylglycine is about 2.4 g / L;

[0061] After merging, 7 L of desorption liquid with a concentration of 7-amino-desacetoxycephalosporanic acid lower than 20 g / L, in which the concentration of 7-amino-desacetoxycephalosporanic acid is 10.7 g / L, and the concentration of D-p-hydroxyphenylglycine is about 2.1 g / L; This part is preferentially used as the desorption liquid for the next batch.

[0062] (3) Preparation of 7-amino-desacetoxycephalosporanic acid

[0063] After transferring the high-concentration analytical solution obtained in the above step (2) to the decolorization tank, start stirring and quickly adjust the pH to 6.8 with sulfuric acid, control the temperature at 10°C to 15°C, add activated carbon, decolorize for 30 minutes, filter off the activated carbon after decolorization is completed, transfer the filtrate to the crystallization tank, continue to adjust the pH of the feed liquid to 6.3 with sulfuric acid. At this time, solids start to precipitate in the system. Continue to add sulfuric acid dropwise and maintain the pH of the feed liquid between 6.3 and 6.0. After the pH no longer changes, carry out crystal cultivation for 30 minutes. Subsequently, continue to add sulfuric acid to adjust the pH of the feed liquid to 3.8, carry out crystal cultivation for 60 minutes, then cool down to 5°C to 10°C for crystal cultivation. After filtration and drying, 785 g of 7-amino deacetoxycephalosporanic acid solid is obtained, with a purity of 99.2%, D-p-hydroxyphenylglycine is not detected, and the conversion yield is 88%.

[0064] (4) Preparation of D-p-hydroxyphenylglycine

[0065] Adjust the pH of the adsorption residual liquid obtained in the above step (2) to 9.1 with 32% sodium hydroxide solution, and then carry out nanofiltration concentration using a nanofiltration membrane with a molecular weight cut-off of 100 Dalton to obtain 14 L of D-p-hydroxyphenylglycine concentrated solution. After concentration, the concentration of D-p-hydroxyphenylglycine is about 67.5 g / L, and the temperature of the feed liquid rises to 42°C - 45°C during the concentration process; after the concentration is completed, transfer the concentrated solution to the crystallization tank, slowly and continuously add hydrochloric acid to the feed liquid until the pH value is 4.8, then cool down to 8°C for crystal cultivation. After filtration and drying, 930 g of D-p-hydroxyphenylglycine solid is obtained, with a content of 99.7%, and the conversion recovery rate is 89.9%.

Claims

1. A method for recovering 7 - amino - deacetoxycephalosporanic acid and D - p - hydroxyphenylglycine from the crystallization mother liquor of cefadroxil, comprising the following steps: Step 1: After the enzymatic production of cefadroxil crystallization mother liquor is separated from cefadroxil crystals, the pH of the mother liquor is adjusted to 7.5 - 8.5 with an alkali solution, and then a hydrolysis reaction is carried out at pH 7.5 - 8.5 and 5°C - 10°C in the presence of immobilized penicillin acylase. After hydrolysis is completed, the immobilized hydrolytic enzyme is separated to obtain the hydrolysis solution of the cefadroxil crystallization mother liquor; Step 2: After adjusting the pH of the hydrolysis solution of the cefadroxil crystallization mother liquor obtained in Step 1 to 6.0 - 7.0 with an acid solution, it is adsorbed with macroporous adsorption resin. Among them, 7 - amino - deacetoxycephalosporanic acid in the hydrolysis solution is adsorbed on the resin, and D - p - hydroxyphenylglycine in the hydrolysis solution passes through the resin and is collected as the adsorption residue solution; after adsorption is completed, the 7 - amino - deacetoxycephalosporanic acid adsorbed on the resin is desorbed with a desorbent to obtain a 7 - amino - deacetoxycephalosporanic acid desorption solution; Step 3: The 7 - amino - deacetoxycephalosporanic acid desorption solution obtained in Step 2 is controlled at a temperature of 10°C - 15°C, decolorized with activated carbon, and then the pH is adjusted to 3.0 - 4.5 with an acid solution. 7 - amino - deacetoxycephalosporanic acid crystallizes out, and then the temperature is lowered to 5°C - 10°C for crystal growth. After filtration and drying, 7 - amino - deacetoxycephalosporanic acid crystals are obtained; Step 4: The adsorption residue solution obtained in Step 2 is adjusted to a pH of 9.0 - 9.5 with an alkali, and then nanofiltration concentration is carried out with a nanofiltration membrane to obtain a concentrated solution of D - p - hydroxyphenylglycine; then at 35°C - 45°C, the pH value of the concentrated solution of D - p - hydroxyphenylglycine is adjusted to 4.5 - 5.5 with hydrochloric acid, and D - p - hydroxyphenylglycine crystals gradually precipitate. Then the temperature is lowered to 5°C - 10°C for crystal growth. After filtration and drying, D - p - hydroxyphenylglycine crystals are obtained. In Step 2, the macroporous adsorption resin used is a macroporous adsorption resin with a pore size of 5 - 30 nanometers, a skeletal structure of styrene - divinylbenzene series, and a specific surface area of greater than 1100 square meters / g; the macroporous adsorption resin is applied in the form of a circular resin column bed by wet packing, and the ratio of the height to the diameter of the circular resin column bed, that is, the height - to - diameter ratio, is 4 or greater; the desorbent used is sodium acetate solution, sodium carbonate solution, or sodium bicarbonate solution.

2. The method according to claim 1, wherein For the cefadroxil crystallization mother liquor, the cefadroxil concentration is 10 - 25 g / L, the 7 - amino - deacetoxycephalosporanic acid concentration is 1 - 5 g / L, the D - p - hydroxyphenylglycine concentration is 5 - 15 g / L, the D - p - hydroxyphenylglycine methyl ester concentration is 0 - 1 g / L, and the pH range is 5.0 - 6.

0.

3. The method according to claim 1, wherein in In Step 1, the alkali solution is sodium hydroxide solution or ammonia water; for the hydrolysis solution of the cefadroxil crystallization mother liquor, the 7 - amino - deacetoxycephalosporanic acid concentration is 8 - 22 g / L, and the D - p - hydroxyphenylglycine concentration is 10 - 30 g / L.

4. The method according to claim 1, characterized in that, The ratio of the height to the diameter of the circular resin column bed, that is, the height - to - diameter ratio, is greater than or equal to 8.

5. The method according to claim 1, characterized in that, in In Step 2, the resolving agent used is a sodium bicarbonate solution, and the concentration of the sodium bicarbonate solution is between 2.0 wt% and 8.0 wt%.

6. The method according to claim 1, characterized in that, in In Step 2, the hydrolysis solution passes through the resin column bed at a flow rate of 1 to 3 times the total volume of the resin per hour. When 7-aminodeacetoxycephalosporanic acid is detected at the outlet at the lower end of the column bed, the feeding of the hydrolysis solution into the column is stopped. Then, the resin is washed with water at a volume of 1.0 to 2.0 times the total volume of the resin to wash out the residual hydrolysis solution in the resin column bed, and the collected washing solution is incorporated into the adsorption residue solution. Then, a resolving agent is used to resolve 7-aminodeacetoxycephalosporanic acid adsorbed on the resin, and the flow rate of the resolving agent is 1.0 to 3.0 times the total volume of the resin per hour.

7. The method according to claim 6, characterized in that, in In Step 2, the eluate flowing out is collected in fractions after the start of resolution, and the concentration of 7-aminodeacetoxycephalosporanic acid in the eluate is detected by high performance liquid chromatography. Among them, the eluates with a 7-aminodeacetoxycephalosporanic acid concentration higher than 20 g / L are combined to obtain a high-concentration eluate, in which the concentration of 7-aminodeacetoxycephalosporanic acid is 22 to 35 g / L and the concentration of D-p-hydroxyphenylglycine is lower than 5 g / L, which is used for the crystallization of 7-aminodeacetoxycephalosporanic acid in Step 3; the fractions with a concentration lower than 20 g / L are used as the resolving agent for the next batch; the eluate that does not contain 7-aminodeacetoxycephalosporanic acid in the early stage is combined into the adsorption residue solution; in the collected adsorption residue solution, the concentration of D-p-hydroxyphenylglycine is 10 to 30 g / L and the concentration of 7-aminodeacetoxycephalosporanic acid is lower than 1 g / L.

8. The method according to claim 1, characterized in that, in In Step 3, the eluates with a 7-aminodeacetoxycephalosporanic acid concentration higher than 20 g / L obtained in Step 2 above are combined to obtain a high-concentration eluate, which is used for the crystallization of 7-aminodeacetoxycephalosporanic acid; at 10°C to 15°C, first, the pH of the high-concentration eluate is adjusted to 6.5 to 7.0 with sulfuric acid. At this time, no solid precipitates in the system. Activated carbon is added, and after stirring and decolorization, the activated carbon is removed by filtration. Subsequently, sulfuric acid, hydrochloric acid or nitric acid is continuously added to adjust the pH value of the feed liquid to 6.3 to 6, and 7-aminodeacetoxycephalosporanic acid crystals start to precipitate, which is the crystal precipitation point. After appropriate crystal growth, the pH value of the feed liquid is then adjusted to 3.0 to 4.5, and crystal growth is carried out while cooling to 5°C to 10°C. After filtration and drying, 7-aminodeacetoxycephalosporanic acid crystals are obtained.

9. The method according to claim 1, characterized in that, in In Step 4, the base is sodium hydroxide solution, potassium hydroxide solution or ammonia water; nanofiltration concentration is carried out using a nanofiltration membrane with a cut-off molecular weight of 100 to 200 Daltons to obtain a D-p-hydroxyphenylglycine concentrate, in which the concentration of D-p-hydroxyphenylglycine is 60 to 70 g / L.

10. The method according to claim 1, characterized in that, in In Step 4, at 35°C to 45°C, the pH value of the D-p-hydroxyphenylglycine concentrate is adjusted to 5.0 to 5.5 with hydrochloric acid, and D-p-hydroxyphenylglycine crystals gradually precipitate. Then, the temperature is lowered to 5°C to 10°C for crystal growth. After filtration and drying, D-p-hydroxyphenylglycine crystals are obtained.

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