Macroporous polyurethane resin capable of specifically adsorbing scutellarin as well as preparation method and application of macroporous polyurethane resin

Abstract

The resin provided by the invention is of a white semitransparent spherical structure, the water content is 55%-70%, the particle size distribution is 0.425-1.00 mm, the specific surface area is 560-750 m < 2 > / g, the pore diameter is intensively distributed in a region of 10-30 nm, and the average pore diameter is 9.35-10.35 nm. The resin is of a white semitransparent spherical structure, the water content is 55%-70%, the particle size distribution is 0.425-1.00 mm, the specific surface area is 560-750 m < 2 > / g, the pore diameter is intensively distributed in a region of 10-30 nm, and the average pore diameter is 9.35-10.35 nm. The resin has the characteristics of high porosity, high specific surface area and uniform resin pore size distribution. In the same technological process for preparing scutellarin through extraction and chromatographic purification of erigeron breviscapus; the resin (the scutellarin adsorption rate is 90.12%, and the product content is 90.33%) is higher in purification efficiency and wider in application range compared with common industrial macroporous adsorption resin ADS-2 (the scutellarin adsorption rate is 19.16%, and the product content is 73.20%), HPD450 (the scutellarin adsorption rate is 21.34%, and the product content is 81.38%), AB-8 (the scutellarin adsorption rate is 15.01%, and the product content is 79.11%) and D101 (the scutellarin adsorption rate is 10.29%, and the product content is 78.68%).

Description

Technical Field

[0001] The invention belongs to the field of natural drug chemistry, and in particular relates to a macroporous polyurethane resin for specifically adsorbing scutellaria baicalin, and a preparation method and application thereof. Background Art

[0002] Based on its three-dimensional porous chemical structure, polyurethane porous materials have been attracting much attention in the scientific community at home and abroad for their high porosity, high specific surface area and excellent adsorption performance. Polyurethane contains a large number of terminal functional groups and has high compatibility, which makes it widely used in the field of chromatography fillers.

[0003] Baicalin is the main biologically active flavonoid component of the Asteraceae plant Erigeron breviscapus. It is an extract extracted and separated from Erigeron breviscapus. It has multiple pharmacological effects such as dilating cerebral blood vessels, reducing cerebral vascular resistance, increasing cerebral blood flow, improving microcirculation, and anti-platelet aggregation. Therefore, it is widely used in clinical treatment of cerebrovascular diseases, cardiovascular diseases, diabetes, kidney diseases, hypoxic pulmonary hypertension, chronic cor pulmonale, rheumatoid arthritis, liver damage and other diseases. It is the main quality control indicator component of Erigeron breviscapus and Erigeron breviscapus preparations.

[0004] Baicalin has many functions, such as improving abnormal blood rheology, antagonizing superoxidation reaction, intervening inflammatory response, regulating endothelial function, intervening cell apoptosis and collagen expression. However, its current common dosage form has defects in oral bioavailability and onset time. In addition, it is difficult to obtain high-purity extracts. Therefore, further in-depth research is needed on the extraction and separation of scutellaria baicalensis and improvement of dosage forms.

[0005] At present, the main separation methods of scutellarin are: solvent extraction, acid precipitation, column chromatography, etc. Solvent extraction uses a wide variety of reagents and a complicated preparation process; the product obtained by acid precipitation is not pure enough; although the column chromatography process is simple, the chromatographic filler is not selective enough for scutellarin, and it is impossible to prepare a scutellarin product with a content greater than 91% (injection grade).

[0006] Therefore, in order to better play the role of baicalin in the treatment of human cardiovascular and cerebrovascular diseases, streamline the separation and purification process of baicalin, and reduce the production cost of baicalin, it is particularly important to develop an adsorption resin with specific adsorption function for baicalin. Summary of the invention

[0007] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a macroporous polyurethane resin for specific adsorption of scutellarin and a preparation method and application thereof. The polyurethane adsorption resin has a chemical structure for specific adsorption of scutellarin, a controllable cross-linking density, and exhibits relatively stable dynamic mechanical properties due to the introduction of dynamic covalent bonds.

[0008] To achieve the above object, the present invention provides the following technical solution: a macroporous polyurethane resin for specific adsorption of scutellarin, wherein the resin is a white translucent spherical structure, has a moisture content of 55%-70%, a particle size distribution of 0.425-1.00 mm, and a specific surface area of ​​560-750 m 2 / g, the pore size is concentrated in the 10-30nm region, and the average pore size is 9.35-10.35nm.

[0009] Furthermore, the preparation method of the macroporous polyurethane resin for specifically adsorbing scutellarin comprises the following steps:

[0010] (1) dissolving polyvinyl alcohol in deionized water at room temperature to prepare a water phase for polymerization reaction, wherein the mass fraction of polyvinyl alcohol in the water phase is 1.0-2.5%;

[0011] (2) dissolving the dihydroxyl-terminated compound in butyl acetate at a temperature of 40° C. to prepare a butyl acetate solution of the dihydroxyl-terminated compound with a mass fraction of 20-30%;

[0012] (3) at a temperature of 40° C., dissolving a cross-linking agent and a nitro compound in a 1:3-1:1 ratio of the hydroxyl group of the dihydroxyl-terminated compound in a good solvent to prepare a solution of a certain concentration, wherein the molar ratio of the nitro compound to the dihydroxyl-terminated compound is 1:1, and the mass ratio of the good solvent to the cross-linking agent is 4:1-6:1;

[0013] (4) mixing the butyl acetate solution prepared in step (2) with a solution of a good solvent, adding a polyisocyanate and a catalyst dibutyltin dilaurate, reacting at a constant speed of 60° C. at normal pressure for 2-6 hours, and standing for 10-30 minutes to obtain an oil phase, wherein the molar ratio of the polyisocyanate to the dihydroxyl compound is 3:1, and the amount of dibutyltin dilaurate is 12%-20% of the mass of the dihydroxyl compound;

[0014] (5) adding an equal mass of the water phase described in step (1) to the oil phase after standing, stirring rapidly until the oil phase is dispersed into oil droplets of 0.4-1.0 mm in the water phase, stopping stirring, standing to room temperature, filtering, washing, and drying to obtain a polyurethane resin, which is used as a matrix resin, referred to as PU;

[0015] (6) Mixing the PU with stannous chloride dihydrate, wherein the mass of the dihydrate and the stannous chloride is 1 / 4-1 / 2 of the mass of the PU, adding concentrated hydrochloric acid while stirring, slowly heating until the stannous chloride dihydrate becomes liquid, then adding sodium hydroxide in multiple portions to raise the pH of the system to neutral, stirring, reacting for 1 hour, and filtering to obtain a mixture A; the amount of concentrated hydrochloric acid added is 30-50% of the mass of the stannous chloride dihydrate;

[0016] (7) dissolving the acetylating agent in benzene to prepare a solution with a mass fraction of 5-10%, with a mass ratio of the acetylating agent solution to the mixture A of 2:1-4:1, mixing the acetylating agent solution with the mixture A, stirring for 24 hours, cooling to room temperature, filtering, washing, and drying.

[0017] Furthermore, the double-terminal hydroxy compound in step (2) is ethylene glycol, polypropylene glycol or polyethylene glycol.

[0018] Furthermore, the double-terminal hydroxy compound in step (2) is ethylene glycol, polypropylene glycol or polyethylene glycol.

[0019] Furthermore, the nitro compound in step (3) is urea, 5-nitro-1,3-diphenol or 4-hydroxy-3-nitrobenzoic acid.

[0020] Furthermore, the polyisocyanate in step (4) is diphenylmethane diisocyanate, toluene diisocyanate, 1,6-hexamethylene diisocyanate, polyhexamethylene diisocyanate or other polyisocyanates.

[0021] Furthermore, the good solvent in step (3) is dimethyl sulfoxide, pyridine or N,N-dimethylformamide.

[0022] The application of the above-mentioned macroporous polyurethane resin for specific adsorption of baicalin is characterized in that the column chromatography purification of baicalin in the baicalin extraction and purification process using Erigeron breviscapus as a raw material or using crude baicalin as a raw material comprises the following steps:

[0023] (a) weighing 20 g of a commercially available crude baicalin product having a baicalin content of 30.05%-79.92%, adding an alkaline reagent and 300-500 mL of deionized water to heat and dissolve, filtering, and adding an equal volume of deionized water to dilute to obtain a baicalin salt solution; or weighing 800 g of a commercially available Chinese medicinal material of Erigeron breviscapus, adding 6000-8000 mL of ethanol with a volume fraction of 80-85%, heating and refluxing for extraction 3 times, each time for 1-2 hours, filtering, combining the filtrates, concentrating under reduced pressure to 500-1000 mL, adding an equal volume of purified water, stirring evenly, leaving for 12 hours, and filtering to obtain a baicalin salt solution having a baicalin concentration of 6.48-12.40 mg / mL;

[0024] (b) Weighing 200-500 g of the macroporous polyurethane resin for specific adsorption of scutellarin prepared by the method of any one of claims 2 to 8, soaking it in deionized water for 12-24 hours, ultrasonically degassing it for 20 minutes, loading it into a glass chromatography column, extracting free water, and then balancing the chromatography column with 4 BV of deionized water at a flow rate of 1-2 BV / h;

[0025] (c) passing the prepared scutellariae baicalin salt solution through the column at a flow rate of 1-2 BV / h, then removing impurities with 2 BV 20% (φB, volume fraction) ethanol, and then eluting with an alkaline solution at a flow rate of 1-2 BV / h, and collecting the eluate when a yellow-brown liquid appears until the eluate becomes colorless;

[0026] (d) The eluate is concentrated under reduced pressure at 40° C. to 300-500 mL, a weak polar reagent is added to the concentrated eluate, and the pH is adjusted with a certain concentration of an acidic reagent at 50-80° C. The solution is allowed to stand and cool for 4-12 hours and then filtered. The filtrate is concentrated under reduced pressure and dried to obtain the scutellarin recovery product. The filter cake is washed and dried to obtain the scutellarin refined product.

[0027] Furthermore, the alkaline agent in step (a) is sodium hydroxide, potassium hydroxide, disodium hydrogen phosphate, sodium carbonate or sodium bicarbonate; the amount of the alkaline agent is 0.75-2.00 times the quality of the crude scutellariae baicalin.

[0028] Furthermore, the weak polar reagent in step (d) is ethanol, acetone, methanol or petroleum ether.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The resin has the characteristics of high porosity, high specific surface area, and uniform distribution of resin pore size. The terminal functional groups are modified so that the resin has strong specific adsorption performance for baicalin, and its adsorption selectivity is significantly higher than that of commercial flavonoid chromatography filler polyamide (30-60 mesh, baicalin adsorption transfer rate of 74.12%, content of 90.01%), and the adsorption and desorption efficiency is higher. In the same process of extracting and chromatographically purifying scutellaria baicalensis to prepare baicalin, the resin (baicalin adsorption rate 90.12%, product content 90.33%) has higher purification efficiency than the commonly used industrial macroporous adsorption resins ADS-2 (baicalin adsorption rate 19.16%, product content 73.20%), HPD450 (baicalin adsorption rate 21.34%, product content 81.38%), AB-8 (baicalin adsorption rate 15.01%, product content 79.11%), and D101 (baicalin adsorption rate 10.29%, product content 78.68%), and the obtained product content is higher and has a wider range of applications. This is because the macroporous adsorption resin purification method used in the industrial production of baicalin is mostly used to remove impurities from baicalin solutions, while the macroporous adsorption resin described in the patent is used for the preparation of baicalin to directly selectively adsorb baicalin. The present invention introduces the polyurethane material into the field of natural drug chemistry by structurally modifying the terminal functional groups of polyurethane to prepare macroporous adsorption resin. The application of such resin in the baicalin production process can simplify the common "extraction-chromatographic column purification-chemical refining 1-chemical refining 2-acidification" baicalin production process in the industry by 25%-40%, greatly reducing the production cost of baicalin. The preparation process of such resin is simple and feasible, with low cost, and has broad application prospects in the industrial production of baicalin. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a characteristic diagram of the appearance of the polyurethane resin for specific adsorption of baicalin prepared in Example 1 of the present invention;

[0032] Figure 2 The figure is the adsorption level of baicalin by various resins at normal temperature and pressure;

[0033] Figure 3 FT-IR images of the macroporous polyurethane resins (PU1-PU6) for specific adsorption of baicalin prepared in Examples 1-6 of the present invention;

[0034] Figure 4 The particle size distribution diagram of the macroporous polyurethane resin (PU1-PU6) for specific adsorption of baicalin prepared in Examples 1-6 of the present invention;

[0035] Figure 5 Average particle size of the macroporous polyurethane resin (PU1-PU6) for specific adsorption of baicalin prepared in Examples 1-6 of the present invention

[0036] Figure 6 The nitrogen isothermal adsorption-desorption curves of the macroporous polyurethane resins (PU1-PU6) for specific adsorption of baicalin prepared in Examples 1-6 of the present invention;

[0037] Figure 7 HPLC chart of the refined baicalin prepared in Examples 7-12 of the present invention. DETAILED DESCRIPTION

[0038] The method of the present invention is described in detail below in conjunction with specific embodiments and drawings.

[0039] 1. Preparation of polyurethane resin for specific adsorption of baicalin

[0040] Example 1

[0041] A method for preparing a polyurethane resin for specifically adsorbing baicalin, comprising the following steps:

[0042] (1) dissolving polyvinyl alcohol in water at room temperature to prepare a water phase for polymerization reaction, wherein the concentration of polyvinyl alcohol in the water phase is 1.5% (wt, mass fraction);

[0043] (2) at a temperature of 40° C., dissolving 100.00 g of PEG2000 in 300.00 g of butyl acetate to prepare a butyl acetate solution having a polyethylene glycol concentration of 25% (wt, mass fraction);

[0044] (3) At a temperature of 40° C., glycerol (3.28 g) having a 1:1 hydroxyl ratio to PEG2000 and 5-nitro-1,3-diphenol (7.76 g) having a 1:1 molar ratio to PEG2000 were dissolved in 13.13 g of N,N-dimethylformamide to prepare a 20% (wt, mass fraction) glycerol solution and a 47% (wt, mass fraction) 5-nitro-1,3-diphenol N,N-dimethylformamide solution;

[0045] (4) Mix a butyl acetate solution of polyethylene glycol with a solution of glycerol and 5-nitrophenol in N,N-dimethylformamide, add 25.23 g of 1,6-hexamethylene diisocyanate and 13.63 g of dibutyltin dilaurate, stir at a constant speed for 2-6 h at normal pressure and 60° C., and let stand for 10-30 min to prepare the oil phase;

[0046] (5) adding an equal amount of water phase to the reaction system after standing, stirring rapidly until the oil phase is dispersed into oil droplets of 0.4-1.0 mm in the water phase, stopping stirring, standing to room temperature, filtering, washing, and drying to obtain 137.27 g of polyurethane resin, which is used as the matrix resin, referred to as PU;

[0047] (6) The above 137.27 g of PU was mixed with 68.13 g of stannous chloride dihydrate, and 20.44 g of concentrated hydrochloric acid was added under stirring. The mixture was slowly heated until the stannous chloride dihydrate became liquid, and then sodium hydroxide was added in several portions to raise the pH of the system to neutral. The mixture was stirred rapidly, and the reaction vessel was cooled with circulating water. After reacting for 1 hour, the mixture was filtered to obtain 135.27 g of mixture A.

[0048] (7) 30.89 g of acetic anhydride was dissolved in benzene to prepare a 7.5% solution. The filtered mixture A was mixed with the acetic anhydride solution, i.e., the mass ratio of the acetic anhydride solution to the mixture A was 3:1. The mixture was stirred at 50° C. for 24 h, and allowed to cool to room temperature. After filtering, washing, and drying, a macroporous polyurethane resin with specific adsorption properties for baicalin was obtained.

[0049] The appearance characteristics and structural parameters of the macroporous polyurethane resin are as follows: the resin is white translucent spherical particles with a particle size of 0.425-1.000mm and a total specific surface area of ​​657m 2 / g, average pore diameter is 9.65nm, pore volume is 1.59mL (see Figure 1 ).

[0050] Example 2

[0051] A method for preparing a polyurethane resin for specifically adsorbing baicalin, comprising the following steps:

[0052] (1) dissolving polyvinyl alcohol in water at room temperature to prepare a water phase for polymerization reaction, wherein the concentration of polyvinyl alcohol in the water phase is 2.0% (wt, mass fraction);

[0053] (2) dissolving 100.00 g of PEG2000 in 400.00 g of butyl acetate at 40° C. to prepare a butyl acetate solution having a polyethylene glycol concentration of 20% (wt, mass fraction);

[0054] (3) At a temperature of 40° C., 1.64 g of glycerol (1:2 in ratio of hydroxyl group to PEG2000) and 7.76 g of 5-nitro-1,3-diphenol (7.76 g in ratio of hydroxyl group to PEG2000) were dissolved in 6.57 g of N,N-dimethylformamide to prepare a 15.30% (wt, mass fraction) glycerol solution and a 72.29% (wt, mass fraction) 5-nitro-1,3-diphenol N,N-dimethylformamide solution;

[0055] (4) Mix a butyl acetate solution of polyethylene glycol with a solution of glycerol and 5-nitrophenol in N,N-dimethylformamide, add 25.23 g of 1,6-hexamethylene diisocyanate and 16.91 g of dibutyltin dilaurate, and stir at a constant speed for 2 h at normal pressure and 60° C., and let stand for 30 min to prepare the oil phase;

[0056] (5) adding an equal amount of water phase to the reaction system after standing, stirring rapidly until the oil phase is dispersed into oil droplets of 0.4-1.0 mm in the water phase, stopping stirring, standing to room temperature, filtering, washing, and drying to obtain 135.63 g of polyurethane resin, which is used as the matrix resin, referred to as PU;

[0057] (6) The above 135.63 g of PU was mixed with 44.88 g of stannous chloride dihydrate, and 20.19 g of concentrated hydrochloric acid was added under stirring. The mixture was slowly heated until the stannous chloride dihydrate became liquid, and then sodium hydroxide was added in several portions to raise the pH of the system to neutral. The mixture was stirred rapidly and cooled with circulating water outside the reaction vessel. After reacting for 1 hour, the mixture was filtered to obtain 133.63 g of mixture A.

[0058] (7) Take 27.13 g of acetic anhydride and dissolve it in benzene to prepare a 5% solution. The filtered mixture A is mixed with the acetic anhydride solution, that is, the mass ratio of the acetic anhydride solution to the mixture A is 4:1. The mixture is stirred and reacted at 50° C. for 24 h. The mixture is allowed to stand and cool to room temperature. After filtering, washing, and drying, a macroporous polyurethane resin with specific adsorption properties for baicalin can be obtained.

[0059] The appearance characteristics and structural parameters of the macroporous polyurethane resin are as follows: the resin is white translucent spherical particles with a particle size of 0.425-1.000mm and a total specific surface area of ​​649m 2 / g, the average pore diameter is 10.12nm, and the pore volume is 1.58mL.

[0060] Example 3

[0061] A method for preparing a polyurethane resin for specifically adsorbing baicalin, comprising the following steps:

[0062] (1) dissolving polyvinyl alcohol in water at room temperature to prepare a water phase for polymerization reaction, wherein the concentration of polyvinyl alcohol in the water phase is 2.5% (wt, mass fraction);

[0063] (2) at a temperature of 40° C., 100.00 g of PEG2000 was dissolved in 233.33 g of butyl acetate to prepare a butyl acetate solution with a polyethylene glycol concentration of 30% (wt, mass fraction);

[0064] (3) At a temperature of 40° C., glycerol (1.09 g) having a 1:3 hydroxyl ratio to PEG2000 and 5-nitro-1,3-diphenol (7.76 g) having a 1:1 molar ratio to PEG2000 were dissolved in N,N-dimethylformamide to prepare a glycerol solution having a concentration of 10% (wt, mass fraction) and a 5-nitro-1,3-diphenol N,N-dimethylformamide solution having a concentration of 70.87% (wt, mass fraction);

[0065] (4) Mix a butyl acetate solution of polyethylene glycol with a solution of glycerol and 5-nitrophenol in N,N-dimethylformamide, add 25.23 g of 1,6-hexamethylene diisocyanate and 13.41 g of dibutyltin dilaurate, and stir at a constant speed for 3 h at normal pressure and 60° C., and let stand for 20 min to prepare the oil phase;

[0066] (5) adding an equal amount of water phase to the reaction system after standing, stirring rapidly until the oil phase is dispersed into oil droplets of 0.3-1.0 mm in the water phase, stopping stirring, standing to room temperature, filtering, washing, and drying to obtain 135.08 g of polyurethane resin, which is used as the matrix resin, referred to as PU;

[0067] (6) The above 135.08 g of PU was mixed with 33.52 g of stannous chloride dihydrate, and 20.11 g of concentrated hydrochloric acid was added under stirring. The mixture was slowly heated until the stannous chloride dihydrate became liquid, and then sodium hydroxide was added in several portions to raise the pH of the system to neutral. The mixture was stirred rapidly and cooled with circulating water outside the reaction vessel. After reacting for 1 hour, the mixture was filtered to obtain 133.08 g of mixture A.

[0068] (7) Take 27.02 g of acetic anhydride and dissolve it in benzene to prepare a 10% solution. The filtered mixture A is mixed with the acetic anhydride solution, that is, the mass ratio of the acetic anhydride solution to the mixture A is 3:1. The mixture is stirred at 50° C. for 24 h, and allowed to cool to room temperature. After filtering, washing, and drying, a macroporous polyurethane resin with specific adsorption properties for baicalin can be obtained.

[0069] The appearance characteristics and structural parameters of the macroporous polyurethane resin are as follows: the resin is white translucent spherical particles with a particle size of 0.425-1.000mm and a total specific surface area of ​​701m 2 / g, the average pore diameter is 9.51nm, and the pore volume is 1.61mL.

[0070] Example 4

[0071] A method for preparing a polyurethane resin for specifically adsorbing baicalin, comprising the following steps:

[0072] (1) dissolving polyvinyl alcohol in water at room temperature to prepare a water phase for polymerization reaction, wherein the concentration of polyvinyl alcohol in the water phase is 1.5% (wt, mass fraction);

[0073] (2) at a temperature of 40° C., dissolving 100.00 g of PEG2000 in 300.00 g of butyl acetate to prepare a butyl acetate solution having a polyethylene glycol concentration of 25% (wt, mass fraction);

[0074] (3) At a temperature of 40° C., mannitol (3.25 g) having a 1:1 ratio of mannitol to PEG2000 hydroxyl group and 5-nitro-1,3-diphenol (7.76 g) having a 1:1 molar ratio of 5-nitro-1,3-diphenol to PEG2000 were dissolved in 13.15 g of N,N-dimethylformamide to prepare a mannitol solution having a concentration of 13% (wt, mass fraction) and a 5-nitro-1,3-diphenol solution having a concentration of 32% (wt, mass fraction) in N,N-dimethylformamide;

[0075] (4) Mix a butyl acetate solution of polyethylene glycol with a solution of mannitol and 5-nitrophenol in N,N-dimethylformamide, add 25.23 g of 1,6-hexamethylene diisocyanate and 18.04 g of dibutyltin dilaurate, stir at a constant speed for 2-6 h at normal pressure and 60° C., and let stand for 10-30 min to prepare the oil phase;

[0076] (5) adding an equal amount of water phase to the reaction system after standing, stirring rapidly until the oil phase is dispersed into oil droplets of 0.4-1.0 mm in the water phase, stopping stirring, standing to room temperature, filtering, washing, and drying to obtain 137.27 g of polyurethane resin, which is used as the matrix resin, referred to as PU;

[0077] (6) The above 137.27 g of PU was mixed with 68.13 g of stannous chloride dihydrate, and 20.44 g of concentrated hydrochloric acid was added under stirring. The mixture was slowly heated until the stannous chloride dihydrate became liquid, and then sodium hydroxide was added in several portions to raise the pH of the system to neutral. The mixture was stirred rapidly, and the reaction vessel was cooled with circulating water. After reacting for 1 hour, the mixture was filtered to obtain 135.27 g of mixture A.

[0078] (7) 30.89 g of acetic anhydride was dissolved in benzene to prepare a 7.5% solution. The filtered mixture A was mixed with the acetic anhydride solution, i.e., the mass ratio of the acetic anhydride solution to the mixture A was 3:1. The mixture was stirred at 40° C. for 24 h, and allowed to cool to room temperature. After filtering, washing, and drying, a macroporous polyurethane resin with specific adsorption properties for baicalin was obtained.

[0079] The appearance characteristics and structural parameters of the macroporous polyurethane resin are as follows: the resin is white translucent spherical particles with a particle size of 0.425-1.000mm and a total specific surface area of ​​701m 2 / g, the average pore diameter is 9.51nm, and the pore volume is 1.61mL.

[0080] Example 5

[0081] A method for preparing a polyurethane resin for specifically adsorbing baicalin, comprising the following steps:

[0082] (1) dissolving polyvinyl alcohol in water at room temperature to prepare a water phase for polymerization reaction, wherein the concentration of polyvinyl alcohol in the water phase is 2.0% (wt, mass fraction);

[0083] (2) at a temperature of 40° C., dissolving 100.00 g of PEG2000 in 400.00 g of butyl acetate to prepare a butyl acetate solution having a polyethylene glycol concentration of 20% (wt, mass fraction);

[0084] (3) At a temperature of 40° C., mannitol (mass: 1.64 g) having a hydroxyl ratio of 1:1 to PEG2000 and 5-nitro-1,3-diphenol (mass: 7.76 g) having a molar ratio of 1:2 to PEG2000 were dissolved in 6.57 g of N,N-dimethylformamide to prepare a mannitol solution having a concentration of 8% (wt, mass fraction) and a 5-nitro-1,3-diphenol solution having a concentration of 40% (wt, mass fraction);

[0085] (4) Mix a butyl acetate solution of polyethylene glycol with a solution of mannitol and 5-nitrophenol in N,N-dimethylformamide, add 25.23 g of 1,6-hexamethylene diisocyanate and 16.91 g of dibutyltin dilaurate, stir at a constant speed for 2-6 h at normal pressure and 60° C., and let stand for 10-30 min to prepare the oil phase;

[0086] (5) adding an equal amount of water phase to the reaction system after standing, stirring rapidly until the oil phase is dispersed into oil droplets of 0.4-1.0 mm in the water phase, stopping stirring, standing to room temperature, filtering, washing, and drying to obtain 135.63 g of polyurethane resin, which is used as the matrix resin, referred to as PU;

[0087] (6) The above 135.63 g of PU was mixed with 44.88 g of stannous chloride dihydrate, and 20.19 g of concentrated hydrochloric acid was added under stirring. The mixture was slowly heated until the stannous chloride dihydrate became liquid, and then sodium hydroxide was added in several portions to raise the pH of the system to neutral. The mixture was stirred rapidly and cooled with circulating water outside the reaction vessel. After reacting for 1 hour, the mixture was filtered to obtain 133.63 g of mixture A.

[0088] (7) Take 27.13 g of acetic anhydride and dissolve it in benzene to prepare a 5% solution. Mix the filtered mixture A with the acetic anhydride solution, i.e., the mass ratio of the acetic anhydride solution to the mixture A is 4:1. Stir the reaction at 40° C. for 18 h, let it stand and cool to room temperature, and filter, wash, and dry to obtain a macroporous polyurethane resin with specific adsorption properties for baicalin.

[0089] The appearance characteristics and structural parameters of the macroporous polyurethane resin are as follows: the resin is white translucent spherical particles with a particle size of 0.425-1.000mm and a total specific surface area of ​​660m 2 / g, the average pore diameter is 10.02nm, and the pore volume is 1.59mL.

[0090] Example 6

[0091] (1) dissolving polyvinyl alcohol in water at room temperature to prepare a water phase for polymerization reaction, wherein the concentration of polyvinyl alcohol in the water phase is 2.0% (wt, mass fraction);

[0092] (2) at a temperature of 40° C., 100.00 g of PEG2000 was dissolved in 233.33 g of butyl acetate to prepare a butyl acetate solution with a polyethylene glycol concentration of 30% (wt, mass fraction);

[0093] (3) At a temperature of 40° C., mannitol (mass: 1.08 g) having a 3:1 hydroxyl ratio of mannitol to PEG2000 and 5-nitro-1,3-diphenol (mass: 7.76 g) having a 1:1 molar ratio of 5-nitro-1,3-diphenol to PEG2000 were dissolved in 6.57 g N,N-dimethylformamide to prepare a mannitol solution having a concentration of 7% (wt, mass fraction) and a 5-nitro-1,3-diphenol solution having a concentration of 50% (wt, mass fraction) in N,N-dimethylformamide;

[0094] (4) Mix a butyl acetate solution of polyethylene glycol with a solution of mannitol and 5-nitrophenol in N,N-dimethylformamide, add 25.23 g of 1,6-hexamethylene diisocyanate and 16.54 g of dibutyltin dilaurate, stir at a constant speed for 2-6 h at normal pressure and 60° C., and let stand for 10-30 min to prepare the oil phase;

[0095] (5) adding an equal amount of water phase to the reaction system after standing, stirring rapidly until the oil phase is dispersed into oil droplets of 0.4-1.0 mm in the water phase, stopping stirring, standing to room temperature, filtering, washing, and drying to obtain 135.08 g of polyurethane resin, which is used as the matrix resin, referred to as PU;

[0096] (6) The above 135.08 g of PU was mixed with 33.52 g of stannous chloride dihydrate, and 20.11 g of concentrated hydrochloric acid was added under stirring. The mixture was slowly heated until the stannous chloride dihydrate became liquid, and then sodium hydroxide was added in several portions to raise the pH of the system to neutral. The mixture was stirred rapidly and cooled with circulating water outside the reaction vessel. After reacting for 1 hour, the mixture was filtered to obtain 133.08 g of mixture A.

[0097] (7) Take 27.02 g of acetic anhydride and dissolve it in benzene to prepare a 10% solution. Mix the filtered mixture A with the acetic anhydride solution, i.e., the mass ratio of the acetic anhydride solution to the mixture A is 3:1. Stir the reaction at 40° C. for 24 h, let it stand and cool to room temperature, and after filtering, washing, and drying, a macroporous polyurethane resin with specific adsorption properties for baicalin can be obtained.

[0098] The appearance characteristics and structural parameters of the macroporous polyurethane resin are as follows: the resin is white translucent spherical particles with a particle size of 0.425-1.000mm and a total specific surface area of ​​712m 2 / g, the average pore diameter is 9.91nm, and the pore volume is 1.62mL.

[0099] 2. Performance test of the polyurethane resin prepared by the present invention for specific adsorption of scutellaria baicalin

[0100] 2.1) Specific adsorption test of baicalin

[0101] 100mL PU1, ADS-2, HPD-450, HPD-600, AB-8, D101, LX-100B, DM130, and XDA-8 resins were selected and loaded into a 30×300mm chromatography column. After pretreatment, 1000mL of baicalin solution with a baicalin concentration of 100 mg / mL was passed through the column at a flow rate of 1BV / h under normal temperature and pressure conditions, and then washed with water for 5BV. The column liquid and the water washing liquid were combined, and the baicalin concentration was detected by HPLC. The adsorption amount and adsorption rate were calculated to obtain the adsorption level diagram of baicalin on various resins at normal temperature and pressure.

[0102] from Figure 2 It can be seen that the macroporous polyurethane resin PU1 synthesized in Example 1 has a higher adsorption rate for baicalin, while other common macroporous adsorption resins basically do not adsorb baicalin. It can be concluded that the macroporous polyurethane resin prepared in the present invention has specific adsorption performance for baicalin.

[0103] 2.2) FT-IR test

[0104] The raw materials and the macroporous polyurethane resins PU1-PU6 synthesized in Examples 1-6 were tested using an Avatar 360 Fourier transform infrared spectrometer. The PU1-PU6 resins were tested using the KBr tablet method, and the other liquid raw materials were tested using the liquid membrane method to obtain FT-IR spectra.

[0105] Figure 3 The peaks of PU1-6 are assigned as follows: 3419 cm -1 N—H stretching vibration peak; 2955cm -1 and 2855cm -1 The stretching vibration peaks of CH3— and —CH2— are 1685cm -1 is the carbonyl stretching vibration peak in carbamate; 1517cm -1 is the characteristic peak of amide bond; 1432cm -1 It is the characteristic peak of N—C—C—NHCO; 1108cm -1 It is the stretching vibration peak of carbamate C—O—C.

[0106] from Figure 3 It can be seen that in the FT-IR spectrum of HDI, 2275 cm -1 The stretching vibration absorption peak of isocyanate -N=C=O almost completely disappeared in the FT-IR spectra of PU1-PU6, indicating that HDI has been almost completely consumed in the reaction.

[0107] 2.3) Particle size distribution and average particle size test

[0108] The macroporous polyurethane resins PU1-PU6 synthesized in Examples 1-6 were sieved using an 8411 electric vibrating sieve machine. 50 g of dried PU1-PU6 resin was weighed, and the total mass was recorded as w (g). The resins were sieved using 0.355 mm (45 mesh), 0.425 mm (40 mesh), 0.500 mm (35 mesh), 0.600 mm (30 mesh), 0.710 mm (25 mesh), 0.850 mm (20 mesh), and 1.000 mm (18 mesh) sieves, and the particle size distribution and average particle size of PU1-PU6 were obtained by testing.

[0109] from Figure 4 It can be seen that the particle size distribution of PU1-PU6 is 0.425mm-0.825mm, and the particle size distribution of PU1-PU6 is uniform.

[0110] from Figure 5It can be seen that the average particle size of PU1 is 0.74 mm, the average particle size of PU2 is 0.75 mm, the average particle size of PU3 is 0.74 mm, the average particle size of PU4 is 0.75 mm, the average particle size of PU5 is 0.75 mm, and the average particle size of PU6 is 0.76 mm.

[0111] 2.4) BET Testing

[0112] The macroporous polyurethane resin PU1-PU6 samples synthesized in Examples 1-6 are dried and placed in sample tubes. Under low temperature (liquid nitrogen bath) conditions, a certain amount of adsorbate gas (N2) is introduced into the sample tubes. The adsorption partial pressure is directly measured by controlling the equilibrium pressure in the sample tubes, and the adsorption amount at the partial pressure point is obtained by the gas state equation. The adsorption equilibrium pressure is increased by gradually adding adsorbate gas to obtain the adsorption-desorption isotherm.

[0113] from Figure 6 It can be seen that the adsorption and TOEFL isotherms of PU1-PU6 are type IV curves, and the hysteresis loop is type H1, indicating that PU1-PU6 are mesoporous materials. The specific surface area of ​​PU1 is 657 m 2 / g, pore volume is 1.59mL; the specific surface area of ​​PU2 is 649m 2 / g, pore volume is 1.58mL; the specific surface area of ​​PU3 is 701m 2 / g, pore volume is 1.61mL; the specific surface area of ​​PU4 is 701m 2 / g, pore volume is 1.61mL; the specific surface area of ​​PU5 is 660m 2 / g, pore volume is 1.59mL; the specific surface area of ​​PU6 is 712m 2 / g, and the pore volume is 1.62mL.

[0114] 3. Application of the macroporous polyurethane resin prepared by the present invention in the adsorption of baicalin

[0115] Example 7

[0116] The adsorption of baicalin in crude baicalin by the adsorption resin:

[0117] (a) 20.00 g of commercially available crude scutellarin (scutellarin content of 54.01%) was accurately weighed, 25 g of sodium bicarbonate and 400 mL of deionized water were added, heated to dissolve, filtered, and an equal volume of deionized water was added to dilute, to prepare a scutellarin salt solution with a scutellarin concentration of 13.72 mg / mL;

[0118] (b) Weigh 200 g of the macroporous polyurethane resin for specific adsorption of baicalin prepared in Example 1, soak it in deionized water for 18 hours, degas it by ultrasonication for 20 minutes, load it into a glass chromatography column, remove free water, and then balance the chromatography column with 4 BV of deionized water at a flow rate of 2 BV / h.

[0119] (c) The prepared scutellariae salt solution was passed through the column at a flow rate of 2 BV / h, and then impurities were removed with 2 BV of 20% (φB, volume fraction) ethanol, and then eluted with 5% (wt, mass fraction) ammonia water at a flow rate of 2 BV / h. When a yellow-brown liquid appeared, the eluate was collected until the eluate became colorless.

[0120] (d) The eluate was concentrated to 300 mL at 40°C to recover ammonia water, and then 1 volume of anhydrous ethanol was added to the remaining eluate, and the pH was adjusted to 1.5 with sulfuric acid at a concentration of 10% (wt, mass fraction) at 50°C, and the solution was filtered after standing and cooling for 12 hours. The filtrate was concentrated and dried under reduced pressure to obtain 4.93 g of scutellarin recovered product, with a yield of 24.65%. The filter cake was washed and dried to obtain 10.72 g of scutellarin refined product, with a yield of 53.60%. The scutellarin content of the scutellarin refined product was 91.12% and the transfer rate was 90.43% by HPLC, the scutellarin content in the recovered product was 10.41%, the transfer rate was 4.75%, and the total transfer rate of the refining process was 95.18%.

[0121] Example 8

[0122] The adsorption of baicalin in crude baicalin by the adsorption resin:

[0123] (a) accurately weighing 20.00 g of commercially available crude scutellarin (scutellarin content of 30.05%), adding 15.01 g of sodium hydroxide and 300 mL of deionized water to dissolve by heating, filtering, and adding an equal volume of deionized water to dilute to prepare a scutellarin salt solution with a scutellarin concentration of 11.55 mg / mL;

[0124] (b) Weigh 300 g of the macroporous polyurethane resin for specific adsorption of baicalin prepared in Example 2, soak it in deionized water for 18 hours, degas it by ultrasonication for 20 minutes, load it into a glass chromatography column, remove free water, and then balance the chromatography column with 4 BV of deionized water at a flow rate of 1 BV / h.

[0125] (c) The prepared scutellariae salt solution was passed through the column at a flow rate of 1 BV / h, and then impurities were removed with 2 BV of 20% (φB, volume fraction) ethanol, and then eluted with 5% (wt, mass fraction) ammonia water at a flow rate of 1 BV / h. When a yellow-brown liquid appeared, the eluate was collected until the eluate became colorless.

[0126] (d) The eluate was concentrated to 400 mL at 40°C to recover ammonia water, and then 1 volume of anhydrous ethanol was added to the remaining eluate, and the pH was adjusted to 2.0 with sulfuric acid at a concentration of 10% (wt, mass fraction) at 50°C, and the solution was filtered after standing and cooling for 12 hours. The filtrate was concentrated and dried under reduced pressure to obtain 4.58 g of scutellarin recovery product, with a yield of 22.90%. The filter cake was washed and dried to obtain 6.65 g of scutellarin refined product, with a yield of 33.25%. The scutellarin content of the scutellarin refined product was 90.35% and the transfer rate was 90.35% by HPLC, the scutellarin content in the recovered product was 8.97%, the transfer rate was 6.18, and the total transfer rate of the refining process was 96.53%.

[0127] Example 9

[0128] The adsorption of baicalin in crude baicalin by the adsorption resin:

[0129] (a) 20.00 g of commercially available crude scutellarin (scutellarin content of 79.92%) was accurately weighed, 22.01 g of disodium hydrogen phosphate and 500 mL of deionized water were added, heated to dissolve, filtered, and an equal volume of deionized water was added to dilute, to prepare a scutellarin salt solution with a scutellarin concentration of 15.77 mg / mL;

[0130] (b) Weigh 500 g of the prepared macroporous polyurethane resin that specifically adsorbs baicalin, soak it in deionized water for 12 hours, degas it by ultrasonication for 20 minutes, load it into a glass chromatography column, remove free water, and then balance the chromatography column with 4 BV of deionized water at a flow rate of 1 BV / h.

[0131] (c) The prepared scutellariae salt solution was passed through the column at a flow rate of 1 BV / h, and then impurities were removed with 2 BV of 20% (φB, volume fraction) ethanol, and then eluted with 10% (wt, mass fraction) ammonia water at a flow rate of 1 BV / h. When a yellow-brown liquid appeared, the eluate was collected until the eluate became colorless.

[0132] (d) The eluate was concentrated to 500 mL at 40°C to recover ammonia water, and then 1 volume of anhydrous ethanol was added to the remaining eluate, and the pH was adjusted to 1.5 with sulfuric acid at a concentration of 10% (wt, mass fraction) at 50°C, and the solution was filtered after standing and cooling for 12 hours. The filtrate was concentrated and dried under reduced pressure to obtain 4.71 g of scutellarin recovery product, with a yield of 23.55%. The filter cake was washed and dried to obtain 15.85 g of scutellarin refined product, with a yield of 79.25%. The scutellarin content of the scutellarin refined product was 91.52% and the transfer rate was 90.75% by HPLC, the scutellarin content in the recovered product was 12.69%, the transfer rate was 3.74, and the total transfer rate of the refining process was 94.49%.

[0133] Example 10

[0134] Adsorption of baicalin in the extract of Erigeron breviscapus by the adsorption resin:

[0135] (a) Weigh 800 g of commercially available Chinese medicinal material Erigeron breviscapus (produced in Luoping, Yunnan, with a content of 0.81%), add 6000 mL of 60% ethanol by volume, heat and reflux for extraction 3 times, each time for 2 hours, filter and combine the filtrates, concentrate under reduced pressure to 500 mL, add an equal volume of purified water and stir evenly, leave for 12 hours, and then filter to obtain a scutellarin salt solution with a scutellarin concentration of 6.48 mg / mL;

[0136] (b) Weigh 500 g of the macroporous polyurethane resin for specific adsorption of baicalin prepared in Example 4, soak it in deionized water for 12 hours, degas it by ultrasonication for 20 minutes, load it into a glass chromatography column, remove free water, and then balance the chromatography column with 4 BV of deionized water at a flow rate of 1 BV / h.

[0137] (c) The prepared scutellariae baicalin salt solution was passed through the column at a flow rate of 1 BV / h, and then impurities were removed with 2 BV of 20% (φB, volume fraction) ethanol, and then eluted with 8% (wt, mass fraction) ammonia water at a flow rate of 1 BV / h. When a yellow-brown liquid appeared, the eluate was collected until the eluate became colorless.

[0138] (d) The eluate was concentrated to 350 mL at 40° C. to recover ammonia water, and then 1 volume of anhydrous ethanol was added to the remaining eluate, and the pH was adjusted to 1.5 with sulfuric acid at a concentration of 15% (wt, mass fraction) at 50° C., and the solution was filtered after standing and cooling for 12 hours. The filtrate was concentrated and dried under reduced pressure to obtain 4.11 g of scutellarin recovery product, with a yield of 0.51%. The filter cake was washed and dried to obtain 6.46 g of scutellarin refined product, with a yield of 0.81%. The scutellarin content of the scutellarin refined product was 89.01% and the transfer rate was 88.74% by HPLC, the scutellarin content in the recovered product was 9.09%, the transfer rate was 5.73%, and the total transfer rate of the refining process was 94.46%.

[0139] Embodiment 11

[0140] Adsorption of baicalin in the extract of Erigeron breviscapus by the adsorption resin:

[0141] (a) Weigh 800 g of commercially available Chinese medicinal material Erigeron breviscapus (produced in Shuangbai, Yunnan, with a content of 1.81%), add 6000 mL of 80% ethanol by volume, heat and reflux for extraction 3 times, each time for 1.5 hours, filter and combine the filtrates, concentrate under reduced pressure to 600 mL, add an equal volume of purified water and stir evenly, leave for 12 hours and then filter to obtain a scutellarin salt solution with a scutellarin concentration of 12.07 mg / mL;

[0142] (b) Weigh 500 g of the macroporous polyurethane resin for specific adsorption of baicalin prepared in Example 5, soak it in deionized water for 12 hours, degas it by ultrasonication for 20 minutes, load it into a glass chromatography column, remove free water, and then balance the chromatography column with 4 BV of deionized water at a flow rate of 1 BV / h.

[0143] (c) The prepared scutellariae salt solution was passed through the column at a flow rate of 1 BV / h, and then impurities were removed with 2 BV of 20% (φB, volume fraction) ethanol, and then eluted with 10% (wt, mass fraction) ammonia water at a flow rate of 1 BV / h. When a yellow-brown liquid appeared, the eluate was collected until the eluate became colorless.

[0144] (d) The eluate was concentrated to 450 mL at 40° C. to recover ammonia water, and then 1 volume of anhydrous ethanol was added to the remaining eluate, and the pH was adjusted to 1.5 with sulfuric acid at a concentration of 20% (wt, mass fraction) at 50° C., and the solution was filtered after standing and cooling for 12 hours. The filtrate was concentrated and dried under reduced pressure to obtain 10.13 g of scutellarin recovered product, with a yield of 1.27%. The filter cake was washed and dried to obtain 14.36 g of scutellarin refined product, with a yield of 1.80%. The scutellarin content of the scutellarin refined product was 89.63% and the transfer rate was 88.89% by HPLC, the scutellarin content in the recovered product was 9.89%, the transfer rate was 6.92%, and the total transfer rate of the refining process was 95.81%.

[0145] Example 12

[0146] Adsorption of baicalin in the extract of Erigeron breviscapus by the adsorption resin:

[0147] (a) Weigh 800 g of commercially available Chinese medicinal material Erigeron breviscapus (produced in Wenshan, Yunnan, with a content of 3.10%), add 8000 mL of 85% ethanol, heat and reflux for extraction 3 times, each time for 1 hour, filter and combine the filtrates, concentrate under reduced pressure to 1000 mL, add an equal volume of purified water and stir evenly, leave for 12 hours and then filter to obtain a scutellarin salt solution with a scutellarin concentration of 12.40 mg / mL;

[0148] (b) Weigh 500 g of the prepared macroporous polyurethane resin that specifically adsorbs baicalin, soak it in deionized water for 12 hours, degas it by ultrasonication for 20 minutes, load it into a glass chromatography column, remove free water, and then balance the chromatography column with 4 BV of deionized water at a flow rate of 1 BV / h.

[0149] (c) The prepared scutellariae salt solution was passed through the column at a flow rate of 1 BV / h, and then impurities were removed with 2 BV of 20% (φB, volume fraction) ethanol, and then eluted with 10% (wt, mass fraction) ammonia water at a flow rate of 1 BV / h. When a yellow-brown liquid appeared, the eluate was collected until the eluate became colorless.

[0150] (d) The eluate was concentrated to 300 mL at 40°C to recover ammonia water, and then 1 volume of anhydrous ethanol was added to the remaining eluate, and the pH was adjusted to 1.5 with sulfuric acid at a concentration of 20% (wt, mass fraction) at 50°C, and the solution was filtered after standing and cooling for 12 hours. The filtrate was concentrated and dried under reduced pressure to obtain 14.53 g of scutellarin recovered product, with a yield of 1.82%. The filter cake was washed and dried to obtain 24.72 g of scutellarin refined product, with a yield of 3.09%. The scutellarin content of the scutellarin refined product was 90.01% and the transfer rate was 89.72% by HPLC, the scutellarin content in the recovered product was 10.98%, the transfer rate was 6.43%, and the total transfer rate of the refining process was 96.15%.

[0151] Figure 7 The HPLC graphs of the refined baicalin products of Examples 7-12 show that the impurity peaks 6-hydroxykaempferol-7-O-β-D-pyranoglucuronide and scutellarin disappear in the HPLC spectra of the crude baicalin after being refined by Examples 7-12. The main component of the refined products of Examples 7-12 is baicalin. After content determination, the baicalin contents of Examples 7-91.12%, 88.35%, 91.52%, 89.01%, 89.63% and 90.01% are obtained, respectively. It can be seen that the macroporous polyurethane resin of the present invention is significantly efficient in refining baicalin.

[0152] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A macroporous polyurethane resin for specifically adsorbing scutellarin, characterized in that: The resin is a white, translucent spherical structure with a moisture content of 55%-70%, a particle size distribution of 0.425-1.00 mm, and a specific surface area of ​​560-750 m 2 / g, the pore size is concentrated in the 10-30nm region, and the average pore size is 9.35-10.35nm.

2. A method for preparing a macroporous polyurethane resin for specific adsorption of scutellarin as claimed in claim 1, characterized in that: The following steps are included: (1) Dissolve polyvinyl alcohol in deionized water at room temperature to prepare the aqueous phase for the polymerization reaction. The mass fraction of polyvinyl alcohol in the aqueous phase is 1.0-2.5%; (2) dissolving the dihydroxyl-terminated compound in butyl acetate at a temperature of 40° C. to prepare a butyl acetate solution of the dihydroxyl-terminated compound with a mass fraction of 20-30%; (3) at a temperature of 40° C., dissolving a cross-linking agent and a nitro compound in a 1:3-1:1 ratio of the hydroxyl group of the dihydroxyl-terminated compound in a good solvent to prepare a solution of a certain concentration, wherein the molar ratio of the nitro compound to the dihydroxyl-terminated compound is 1:1, and the mass ratio of the good solvent to the cross-linking agent is 4:1-6:1; (4) mixing the butyl acetate solution prepared in step (2) with a solution of a good solvent, adding a polyisocyanate and a catalyst dibutyltin dilaurate, reacting at a constant speed of 60° C. at normal pressure for 2-6 hours, and standing for 10-30 minutes to obtain an oil phase, wherein the molar ratio of the polyisocyanate to the dihydroxyl compound is 3:1, and the amount of dibutyltin dilaurate is 12%-20% of the mass of the dihydroxyl compound; (5) adding an equal mass of the water phase described in step (1) to the oil phase after standing, stirring rapidly until the oil phase is dispersed into oil droplets of 0.4-1.0 mm in the water phase, stopping stirring, standing to room temperature, filtering, washing, and drying to obtain a polyurethane resin, which is used as a matrix resin, referred to as PU; (6) Mixing the PU with stannous chloride dihydrate, wherein the mass of the dihydrate and the stannous chloride is 1 / 4-1 / 2 of the mass of the PU, adding concentrated hydrochloric acid while stirring, slowly heating until the stannous chloride dihydrate becomes liquid, then adding sodium hydroxide in multiple portions to raise the pH of the system to neutral, stirring, reacting for 1 hour, and filtering to obtain a mixture A; the amount of concentrated hydrochloric acid added is 30-50% of the mass of the stannous chloride dihydrate; (7) dissolving the acetylating agent in benzene to prepare a solution with a mass fraction of 5-10%, with a mass ratio of the acetylating agent solution to the mixture A of 2:1-4:1, mixing the acetylating agent solution with the mixture A, stirring for 24 hours, cooling to room temperature, filtering, washing, and drying.

3. The method for preparing a macroporous polyurethane resin for specific adsorption of scutellarin according to claim 2, characterized in that: The double-terminal hydroxy compound in step (2) is ethylene glycol, polypropylene glycol or polyethylene glycol.

4. The method for preparing a macroporous polyurethane resin for specific adsorption of scutellarin according to claim 2, characterized in that: The cross-linking agent in step (3) is glycerol, sodium alginate, dimethylol propionic acid or mannitol.

5. The method for preparing a macroporous polyurethane resin for specific adsorption of scutellarin according to claim 2, characterized in that: The nitro compound in step (3) is urea, 5-nitro-1,3-diphenol or 4-hydroxy-3-nitrobenzoic acid.

6. The method for preparing a macroporous polyurethane resin for specific adsorption of scutellarin according to claim 2, characterized in that: The polyisocyanate in step (4) is diphenylmethane diisocyanate, toluene diisocyanate, 1,6-hexamethylene diisocyanate, polyhexamethylene diisocyanate or other polyisocyanates.

7. The method for preparing a macroporous polyurethane resin for specific adsorption of scutellarin according to claim 2, characterized in that: The good solvent in step (3) is dimethyl sulfoxide, pyridine or N,N-dimethylformamide.

8. An application of a macroporous polyurethane resin for specific adsorption of scutellaria baicalin, characterized in that: The column chromatography purification of baicalin in the baicalin extraction and purification process using Erigeron breviscapus as a raw material or using crude baicalin as a raw material comprises the following steps: (a) weighing 20 g of a commercially available crude baicalin product having a baicalin content of 30.05%-79.92%, adding an alkaline reagent and 300-500 mL of deionized water to heat and dissolve, filtering, and adding an equal volume of deionized water to dilute to obtain a baicalin salt solution; or weighing 800 g of a commercially available Chinese medicinal material of Erigeron breviscapus, adding 6000-8000 mL of ethanol with a volume fraction of 80-85%, heating and refluxing for extraction 3 times, each time for 1-2 hours, filtering, combining the filtrates, concentrating under reduced pressure to 500-1000 mL, adding an equal volume of purified water, stirring evenly, leaving for 12 hours, and filtering to obtain a baicalin salt solution having a baicalin concentration of 6.48-12.40 mg / mL; (b) Weighing 200-500 g of the macroporous polyurethane resin for specific adsorption of scutellarin prepared by the method of any one of claims 2 to 8, soaking it in deionized water for 12-24 hours, ultrasonically degassing it for 20 minutes, loading it into a glass chromatography column, extracting free water, and then balancing the chromatography column with 4 BV of deionized water at a flow rate of 1-2 BV / h; (c) passing the prepared scutellariae baicalin salt solution through the column at a flow rate of 1-2 BV / h, and then removing impurities with 2 BV 20% (φB, volume fraction) ethanol, and then eluting with an alkaline solution at a flow rate of 1-2 BV / h, and collecting the eluate when a yellow-brown liquid appears until the eluate becomes colorless; (d) The eluate is concentrated under reduced pressure at 40° C. to 300-500 mL, a weak polar reagent is added to the concentrated eluate, and the pH is adjusted with a certain concentration of an acidic reagent at 50-80° C. The solution is allowed to stand and cool for 4-12 hours and then filtered. The filtrate is concentrated under reduced pressure and dried to obtain the scutellarin recovery product. The filter cake is washed and dried to obtain the scutellarin refined product.

9. The use of the macroporous polyurethane resin for specific adsorption of scutellarin according to claim 9, characterized in that: The alkaline agent in step (a) is sodium hydroxide, potassium hydroxide, disodium hydrogen phosphate, sodium carbonate or sodium bicarbonate; the amount of the alkaline agent is 0.75-2.00 times the quality of the crude baicalin.

10. The use of the macroporous polyurethane resin for specific adsorption of scutellarin according to claim 8, characterized in that: The weak polar reagent in step (d) is ethanol, acetone, methanol or petroleum ether.

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