GMP continuous counter-current extraction decolorization process method

Abstract

The invention relates to a GMP (Good Manufacturing Practice) continuous counter-current extraction decolorization process method, and belongs to the technical field of GMP preparation processes. Comprising the following steps: providing a GMP crude product aqueous solution and carrying out pretreatment; carrying out continuous countercurrent contact on the pretreated GMP water phase and the functionalized magnetic nanoparticles in extraction equipment, and adsorbing the pigment on the magnetic nanoparticles to obtain a preliminarily decolored GMP water phase; separating the pigment-loaded functionalized magnetic nanoparticles from the preliminarily decolored GMP aqueous phase by applying a magnetic field; carrying out regeneration treatment on the separated functionalized magnetic nanoparticles loaded with the pigment, and returning the regenerated magnetic nanoparticles to the step (b) for recycling; and carrying out post-treatment on the preliminarily decolored GMP water phase to obtain a high-purity GMP product. According to the invention, the problems of contradiction between decoloring efficiency and product yield, discontinuous operation and the like in the prior art are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to a GMP continuous countercurrent extraction decolorization process method, belonging to the technical field of GMP preparation process. BACKGROUND

[0002] Guanosine disodium (GMP) as an important nucleoside food additive and pharmaceutical intermediates, is widely used in seasoning fresh, pharmaceutical preparations and other fields. Its production method mainly adopts biological fermentation process, through Bacillus subtilis or glutamic acid coryneform bacteria strain to remove purine nucleotide biosynthesis feedback inhibition to achieve high yield.

[0003] Although the existing fermentation process can achieve high yield, pigment impurities are often generated in the fermentation broth. These impurities not only affect the appearance quality of the final product, but also can form covalent combination with GMP molecules, resulting in a decrease in purity. Therefore, the decolorization process is a key link in the GMP refining process. Traditional decolorization processes mostly use activated carbon adsorption or single-stage solvent extraction, but have defects such as low adsorption efficiency, high GMP loss rate, and large consumption of organic solvents.

[0004] For example, patent CN101619086B discloses a technical solution for decolorization using activated carbon. The process adds 10% carbon powder by mass under high temperature conditions, which not only has poor adsorption selectivity and easily leads to adsorption loss of the target product, but also has problems such as complicated separation and subsequent processing of activated carbon, dust pollution, and high labor intensity. In addition, the regeneration of carbon powder is difficult, and continuous operation cannot be realized, which restricts the improvement of production efficiency.

[0005] Another patent CN205241578U uses a fixed bed activated carbon column for decolorization, which can achieve partial continuity, but still has problems such as decolorization efficiency decay over time, frequent replacement or regeneration of carbon materials, and large equipment footprint. Especially for GMP molecules, activated carbon adsorption lacks specificity, which easily causes entrainment loss of effective components and affects the final yield.

[0006] In summary, the existing decolorization processes generally have the contradiction between decolorization efficiency and product yield, and problems such as difficulty in regenerating adsorption materials and discontinuous operation.

[0007] Therefore, a new scheme is needed to solve this problem. SUMMARY

[0008] The technical problem to be solved by the present application is to provide a GMP continuous countercurrent extraction decolorization process method, which solves the contradiction between decolorization efficiency and product yield, and the problem of discontinuous operation in the prior art.

[0009] The technical problem to be solved by the present application is solved by the following technical scheme: A GMP continuous countercurrent extraction decolorization process method, comprising the following steps: (a) providing a GMP crude aqueous solution and performing pretreatment; (b) performing continuous countercurrent contact of the pretreated GMP aqueous phase and functionalized magnetic nanoparticles in an extraction device, adsorbing pigments on the magnetic nanoparticles to obtain a preliminarily decolorized GMP aqueous phase; (c) separating the functionalized magnetic nanoparticles loaded with pigments from the preliminarily decolorized GMP aqueous phase by applying a magnetic field; (d) performing regeneration treatment on the separated functionalized magnetic nanoparticles loaded with pigments and returning the regenerated magnetic nanoparticles to step (b) for recycling; (e) performing post-treatment on the preliminarily decolorized GMP aqueous phase to obtain a high-purity GMP product.

[0010] The application is further provided as follows: the pretreatment comprises using a laser irradiation method, and a laser with a wavelength in the visible light band and matched with the characteristic absorption peak of the target pigment is used to irradiate the GMP crude aqueous solution; The laser irradiation method is completed immediately before the feed inlet of the extraction device.

[0011] The application is further provided as follows: step (b) is performed in a magnetically stabilized fluidized bed adsorption tower; The tower body of the magnetically stabilized fluidized bed adsorption tower is made of a non-magnetic material; At least one set of electromagnetic coils is wrapped around the outside of the tower body, and the electromagnetic coils can generate a uniform-intensity axial static magnetic field in the internal cavity of the tower body when energized, the direction of the axial static magnetic field being parallel to the axis of the tower body; The tower body is provided with a liquid distributor and a magnetic particle inlet at the bottom and a clear liquid overflow port at the top; The average particle size of the magnetic nanoparticles is 20-50 nm.

[0012] The application is further provided as follows: the number of electromagnetic coils matches the number of extraction stages, and each set of electromagnetic coils is independently sleeved on the outside of the tower body at a position corresponding to each tower plate; The electromagnetic coils are Helmholtz coil pairs or solenoid coils; By independently regulating the current intensity of each set of electromagnetic coils, an axial magnetic field of 0.1-0.5 T is formed in the tower, and a magnetic field gradient along the tower height can be generated; The empty tower flow rate of the fluidized bed is maintained in the range of 0.5-2.0 cm / s, so that the functionalized magnetic nanoparticles form a stable dispersed fluidized bed layer under the joint action of the magnetic field and the fluid.

[0013] The application is further provided as follows: in step (c), the magnetic field is a static magnetic field; Or, a low-frequency alternating magnetic field with a frequency of 5Hz to 10Hz is applied in the late separation stage to disturb the magnetic nanoparticle agglomerates and promote the release of the entrained droplets.

[0014] The application further provides that the interior of the magnetically stable fluidized bed adsorption tower is provided with a plurality of layers of horizontally arranged flow guides, which separate the space in the tower into a plurality of serially connected adsorption stage chambers; Each of the adsorption stage chambers corresponds to a group of external electromagnetic coils; The flow guides are porous plates or screens with an opening rate of 40%-60% to allow the passage of fluid and magnetic nanoparticles; The opening areas on the flow guides of adjacent layers are arranged in a staggered manner in the horizontal direction; Under the joint guidance of the gradient magnetic field and the staggered flow guides, the magnetic nanoparticles flow along a zigzag path from top to bottom, and fully multi-stage countercurrent contact with the upwardly flowing GMP aqueous phase is achieved.

[0015] The application further provides that in step (a), the pretreatment further comprises adjusting the pH of the GMP crude aqueous solution to 8.5-9.0, adjusting the temperature to 35-40℃, and adding 3%-6% of sodium chloride and 0.01%-0.03% of β-cyclodextrin based on the mass of the aqueous phase.

[0016] The application further provides that the functionalized magnetic nanoparticles comprise a superparamagnetic ferroferric oxide core, a silica separation layer wrapped around the core, and a choline-based ionic liquid ligand grafted to the separation layer through chemical bonding.

[0017] The application further provides that in step (d), the regeneration treatment comprises eluting the pigment-loaded magnetic nanoparticles using an ethanol aqueous solution with a concentration of 50%-60%, and then washing with deionized water.

[0018] The application further provides that in step (e), the post-treatment comprises: The preliminarily decolorized GMP aqueous phase is sequentially passed through a first adsorption column filled with macroporous adsorption resin and a second adsorption column filled with high-selectivity anion exchange resin for deep purification; The purified GMP aqueous phase is fed into a programmed cooling crystallizer, ethanol is used as a solventing agent for programmed variable-speed dropping, and 2%-3% of sodium chloride and 2%-3% of sodium phosphate based on the mass of the aqueous phase are added as crystal type modifiers, and finally high-purity GMP crystals are obtained.

[0019] The application has the following beneficial effects: The combination of wavelength-matched laser pretreatment and functionalized magnetic nanoparticles activates and specifically adsorbs pigment molecules, improving decolorization efficiency while reducing GMP loss of target products. Countercurrent extraction is carried out in a magnetically stabilized fluidized bed, enabling continuous operation and improving production efficiency and equipment utilization. The functionalized magnetic nanoparticles can be efficiently regenerated through simple magnetic separation and mild ethanol-water washing, allowing for multiple recycling cycles, reducing raw material consumption and solid waste treatment costs, resulting in good process economics. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the process flow of the present invention.

[0021] Figure 2 This is a schematic diagram of the structure of the magnetically stabilized fluidized bed adsorption tower in this invention.

[0022] In the diagram: 1. Tower body; 2. Electromagnetic coil; 3. Liquid distributor; 4. Clear liquid overflow port; 5. Magnetic particle inlet; 6. Guide plate; 7. Laser. Detailed Implementation

[0023] To facilitate a clear understanding of the technical means, creative features, objectives, and effects of this invention, the invention will be further described below in conjunction with specific illustrations.

[0024] like Figure 1 As shown, the GMP continuous countercurrent extraction decolorization process includes the following steps: Step (a): Provide a GMP crude aqueous solution and pretreatment.

[0025] The pretreatment includes adjusting the pH of the crude GMP aqueous solution to 8.5-9.0, adjusting the temperature to 35-40°C, and adding 3%-6% sodium chloride and 0.01%-0.03% β-cyclodextrin by mass of the aqueous phase. Preferably, the optimal operating parameters are adjusting the pH to 8.8 and adding 5% sodium chloride and 0.02% β-cyclodextrin by mass of the aqueous phase.

[0026] By adjusting the physicochemical conditions of the crude GMP aqueous solution, an optimal environment was created for the efficient adsorption of functionalized magnetic nanoparticles. The pH of the solution was adjusted to a weakly alkaline range of 8.5 to 9.0. This alkaline environment helps maintain the stability of the GMP molecules themselves, preventing acid hydrolysis during subsequent processing. Furthermore, under weakly alkaline conditions, many pigment impurities ionize their phenolic hydroxyl or carboxyl groups, thereby enhancing their polarity and reactivity, making them more easily recognized and captured by the subsequent functionalized magnetic nanoparticles.

[0027] Meanwhile, the temperature of the solution is adjusted and maintained at 35 to 40°C. The control of the temperature is crucial to the kinetics of the adsorption process. It can reduce the viscosity of the solution and accelerate the mass transfer rate between the pigment molecules and the adsorbent particles.

[0028] Sodium chloride is added in an amount of 3% to 6% of the mass of the aqueous phase. Sodium chloride is mainly used to increase the ionic strength of the solution. Higher ionic strength can compress the double electric layer in the solution, effectively weakening the electrostatic repulsion between the pigment molecules and the magnetic nanoparticles, thereby promoting the adsorption process. In addition, the increase of ionic strength also helps to weaken the weak interaction between the pigment molecules and the GMP, so that the pigment molecules tend to bind to the functionalized magnetic nanoparticles.

[0029] Beta-cyclodextrin is added in an amount of 0.01% to 0.03% of the mass of the aqueous phase. Beta-cyclodextrin is a cyclic oligosaccharide composed of 7 glucose units. The molecular structure of beta-cyclodextrin has a hydrophobic inner cavity and a hydrophilic outer surface. This property enables it to form host-guest inclusion complexes with many pigment molecules with hydrophobic structures through inclusion. On the one hand, it can solubilize part of the hydrophobic pigment and prevent it from aggregating into large particles; on the other hand, the inclusion of beta-cyclodextrin can change the state of existence of the pigment molecules, so that part of the chromophore group is exposed or the microenvironment changes, thereby activating the pigment molecules to some extent and enhancing their binding capacity with specific ligands on the subsequent functionalized magnetic nanoparticles.

[0030] Through precise and coordinated pH adjustment, temperature control and the introduction of functional additives, the selectivity and efficiency of the subsequent countercurrent extraction decolorization step are improved from the aspects of electricity, mass transfer, molecules, etc.

[0031] As shown in Figure 2 To further improve the efficiency of extraction, the pretreatment also includes using a laser irradiation method, specifically using a laser 7 with a wavelength in the visible light band and matching the characteristic absorption peak of the target pigment to irradiate the GMP crude aqueous solution. The laser irradiation process is completed immediately before the feed inlet of the extraction equipment to ensure that the pigment molecules have been effectively activated before entering the subsequent countercurrent extraction stage, thereby improving the decolorization efficiency.

[0032] The laser irradiation treatment is completed immediately before the feed inlet of the extraction equipment to ensure that the reactivity of the pigment molecules in the crude aqueous solution has been improved before the solution enters the countercurrent extraction contact section, and immediately after the improvement, the contact extraction is carried out to reduce the thermal diffusion between the molecules.

[0033] The laser 7 is selected to have a specific wavelength in the visible light range. By performing an ultraviolet-visible spectrum scan on the GMP crude product in advance, the characteristic absorption peak of one or more dominant pigment molecules is identified, and the laser output wavelength is selected accordingly. For example, if the main pigment is a certain kind of ketone or phenol derivative, its maximum absorption peak may be located in the range of 300-500 nm, and the corresponding laser 7 with an emission wavelength in this range is selected, such as a semiconductor laser with a wavelength of 455 nm.

[0034] This wavelength matching ensures that the laser photon energy can be efficiently absorbed by the target pigment molecules, causing them to transition from the ground state to the excited state, weakening the chromophore or chemical bond in the molecular structure, and enhancing the tendency and binding capacity of the pigment molecules to be adsorbed by the functionalized magnetic nanoparticles in the subsequent steps.

[0035] To overcome the problem of uneven irradiation of the liquid flow cross-section and low energy utilization efficiency, a specially designed optical lens group is installed at the exit end of the laser 7. This lens group reshapes and expands the original laser beam, converting it from a small energy-concentrated spot to a large-area rectangular or elliptical spot with uniform energy density distribution, which can cover the entire cross-sectional area of the liquid flow pipeline.

[0036] Specifically, the reshaped laser spot needs to ensure that it covers more than 90% of the cross-sectional area of the flowing liquid, and most preferably achieves a coverage rate of 95%, thereby minimizing the irradiation dead angle and ensuring that all pigment molecules in the solution flowing through this area are subjected to sufficient and uniform laser irradiation.

[0037] To achieve this goal, the lens group configuration typically includes one or more collimating lenses and a beam expander. In production practice, aspherical lenses can be used to better eliminate aberrations and achieve uniform light field distribution. The laser 7 itself is preferably operated in pulse mode, with single-pulse energy controlled between 10 and 20 millijoules, preferably 15 millijoules; the pulse frequency is set in the range of 30 to 60 Hz, preferably 50 Hz; and the pulse width is between 30 and 100 nanoseconds.

[0038] This short-pulse, intermittent mode provides high-intensity instantaneous energy input at the molecular level, effectively activating the pigment molecules, while avoiding the accumulation of laser energy, which can cause the solution as a whole to overheat, thereby protecting the GMP molecules.

[0039] The laser irradiation unit is integrated into a short-range flow channel, which is made of high-transmittance quartz or special glass, and has laser incident windows arranged on both sides or periphery. The solution flows continuously through the flow cell at a certain flow rate, and after receiving uniform laser irradiation, it is immediately sent to the subsequent extraction equipment.

[0040] Through the laser pretreatment step, efficient and uniform activation of pigment molecules is achieved, and the stability of the target product GMP is not affected, so that the subsequent extraction step can adsorb pigment molecules in a shorter time.

[0041] Step (b): The pretreated GMP aqueous phase is continuously contacted with functionalized magnetic nanoparticles in an extraction device to adsorb pigments on the magnetic nanoparticles, obtaining a preliminary decolorized GMP aqueous phase.

[0042] The pretreated GMP aqueous phase is continuously contacted with specially prepared functionalized magnetic nanoparticles, thereby efficiently and selectively adsorbing pigments on the magnetic nanoparticles. The particles are composite nanomaterials with a core-shell structure, and the core is composed of superparamagnetic ferroferric oxide nanoparticles. Superparamagnetism ensures that the particles can be rapidly magnetized and produce strong magnetic attraction under an external magnetic field, and their remanence is almost zero after the magnetic field is removed, avoiding permanent magnetic agglomeration between particles, allowing them to disperse well in the aqueous phase and be easily recycled. The average particle size of the core should be controlled between 20-50 nanometers.

[0043] Outside the magnetic core, there is a dense silica isolation layer. This isolation layer is synthesized by the classic Stöber method or microemulsion method, and its thickness is usually 5-10 nanometers. The silica layer effectively isolates the ferroferric oxide core from the external aqueous environment, preventing the magnetic core from being eroded and passivated in acidic or oxidative environments, greatly improving the chemical stability of the nanoparticles; moreover, the silica surface is rich in silanol groups, providing abundant active sites for subsequent functionalization modification; and the silica layer provides a biocompatible surface, reducing non-specific adsorption with GMP molecules.

[0044] Finally, choline-based ionic liquid ligands are covalently grafted to the surface of the silica isolation layer through chemical bonding. Typically, a silane coupling agent is used to activate the silica surface, introducing active groups such as amino or epoxy groups, which are then connected to choline-based ionic liquids containing carboxyl or hydroxyl groups through amidation or etherification reactions.

[0045] The selected choline-based ionic liquid ligand has a choline cation and an anion that can be an amino acid radical, a carboxylate radical, or other organic anions. The ligand combines the high stability and low volatility of ionic liquids with the specific recognition ability of choline for some polar pigment molecules. The quaternary ammonium salt cation and specific anion in the ligand molecular structure can interact with pigment molecules in the GMP crude aqueous solution through ion exchange, hydrogen bonding, π-π stacking, and other synergistic effects, achieving high-strength and high-selectivity interactions to efficiently adsorb pigments while minimizing the entrainment loss of the target product GMP.

[0046] AsFigure 2 As shown, the countercurrent extraction contact process is carried out in a magnetically stabilized fluidized bed adsorption column. The column body 1 is made of non-magnetic material, such as 316L stainless steel, glass or engineering plastics such as polyvinylidene fluoride, to ensure that the externally applied magnetic field can penetrate the column wall without interference, forming a pure and uniformly strong magnetic field space in the column cavity, avoiding the weakening or distortion effect of the column body 1 material on the magnetic field.

[0047] To achieve the manipulation of the magnetic particles in the column, a plurality of electromagnetic coils 2 are wrapped around the outside of the column body 1. The number of these electromagnetic coils 2 matches the number of extraction stages, with each stage of the extraction chamber corresponding to a set of independently wrapped coils outside the column body 1. The coil type is preferably a Helmholtz coil pair that can generate a highly uniform axial magnetic field, or a more compact solenoid coil. By independently and precisely regulating the input current intensity of each set of coils, an adjustable axial static magnetic field with a strength in the range of 0.1 Tesla to 0.5 Tesla can be generated along the axial direction in the column.

[0048] The core function of this magnetic field gradient is to provide a continuous and direction-specific magnetic field force for the functionalized magnetic nanoparticles dispersed in the liquid medium. Superparamagnetic nanoparticles are magnetized in the gradient magnetic field and subjected to a force pointing from the area with weaker magnetic field to the area with stronger magnetic field. By designing the magnetic field strength to gradually increase from top to bottom along the column height, the direction of the magnetic field force is downward, consistent with the direction of the gravitational force of the particles themselves.

[0049] Regarding the application scheme of the magnetic field gradient, this embodiment mainly adopts a steady and unidirectional increasing gradient mode. Specifically, the optimal scheme is to set the magnetic field strength at the top of the column at a relatively low 0.1 Tesla, and set the magnetic field strength at the bottom of the column at a relatively high 0.5 Tesla, thereby forming a stable gradient field with linear or nonlinear increasing magnetic field strength from top to bottom.

[0050] The downward magnetic field force is used to balance the upward drag force of the liquid flowing from bottom to top on the particles. By controlling the dynamic balance between the three, the fluidization state of the magnetic particles can be finely controlled, forming a uniform and dispersed fluidized bed layer without bubbles and channeling in the column. This fluidization state expands the solid-liquid contact area and eliminates the internal diffusion limitation in the fixed bed, ensuring that the magnetic particles are in a determined force balance state at each cross-sectional height in the column, thereby forming a stable particle concentration distribution. This improves the mass transfer rate and capacity of pigment adsorption.

[0051] In steady state magnetic field operation, although superparamagnetic particles theoretically have no remanence, but under high concentration and strong magnetic field, temporary and loose agglomerates can be formed. By applying a low frequency alternating magnetic field, the frequency of which is 5Hz to 10Hz, periodic shear and disturbance can be generated on these agglomerates, breaking the agglomerates and exposing the wrapped inner molecular adsorption sites, so that the effective utilization rate of the adsorbent can be improved to a certain extent. Periodic dynamic magnetic field is suitable for specific operation stage, such as auxiliary means to prevent bed dead zone, rather than the conventional mode of main adsorption process.

[0052] Moreover, in the process of separating magnetic particles from liquid phase, especially in the later stage, a small amount of liquid droplets may be entrained in the agglomerates of magnetic particles. By applying a low frequency alternating magnetic field, the magnetic particle clusters can be continuously vibrated and restructured, which helps to release the entrained liquid droplets, thereby reducing the entrainment loss of target product GMP and improving product yield.

[0053] The bottom of the tower body 1 is provided with a liquid distributor 3. The liquid distributor 3 ensures that the pretreated GMP aqueous phase entering from the bottom can be uniformly distributed on the entire cross section of the tower and rise. The clear liquid overflow port 4 at the top is used to collect the GMP aqueous phase after preliminary decolorization. The upper part of the tower body 1 is provided with a magnetic particle inlet 5, and the functionalized magnetic nanoparticles are added from the inlet.

[0054] During the entire operation process, the empty tower flow rate of the fluidized bed is maintained in the range of 0.5-2.0cm / s, preferably, the empty tower flow rate is maintained at 1.2cm / s. At this flow rate, the magnetic particles moving from top to bottom are subjected to the combined action of gravity, fluid drag force from bottom to top and magnetic field force generated by magnetic field gradient. The adjustable magnetic field force is used to resist and adjust the movement of the particles, so that the magnetic nanoparticle group can expand in the tower and be in a uniform suspended fluidized state, i.e. form a dispersed fluidized bed. This fluidized state promotes the mass transfer efficiency between the solid-liquid two phases and eliminates the diffusion limitation problem existing in the fixed bed operation.

[0055] In order to realize multi-stage countercurrent extraction, a flow guide plate 6 is arranged in the tower. The horizontally arranged flow guide plate 6 separates the space in the tower into a plurality of series of adsorption stage chambers, each stage corresponding to a group of external electromagnetic coils 2 to realize independent magnetic field regulation. The flow guide plate 6 is usually a perforated plate or screen, and the opening rate is designed to be between 40% and 60%, which allows the fluid and magnetic particles to pass through smoothly, and can also redistribute the two-phase fluid to a certain extent and promote mixing.

[0056] Further, the open hole regions on the adjacent baffles 6 are arranged in staggered manner in horizontal direction. In combination with the magnetic field gradient along the tower height, the magnetic nanoparticles are guided to flow down along the zigzag path. At the same time, the GMP aqueous phase flows continuously from bottom to top, achieving sufficient counter-current contact with the magnetic particles in each stage chamber, improving the mass transfer driving force and decolorization efficiency, and ultimately making the clear liquid at the outlet reach a high purity, while the magnetic particles are loaded with high concentration of pigments.

[0057] Step (c): separating the functionalized magnetic nanoparticles loaded with pigments from the preliminarily decolorized GMP aqueous phase by applying a magnetic field.

[0058] The separation process is to apply a static magnetic field with constant strength. The static magnetic field is generated by the electromagnetic coil 2 at the bottom of the adsorption tower after a constant direct current is applied. Under the action of this steady magnetic field, the functionalized nanoparticles with superparamagnetic property are rapidly magnetized and subjected to magnetic field force, moving, gathering and settling rapidly towards the area with the strongest magnetic field strength.

[0059] This separation process separates most of the magnetic particles from the aqueous phase, forming a dense magnetic floc, while the clear preliminarily decolorized liquid is discharged as supernatant from the overflow port. The static magnetic field separation has the advantages of simple operation, relatively low energy consumption and high separation efficiency, and is the most reliable way to achieve the main separation.

[0060] However, under the action of the static magnetic field, a small amount of GMP aqueous droplets that have not been displaced may be entrained inside the magnetic floc. In order to further recover these entrained product droplets and improve the final yield, a low-frequency alternating magnetic field is introduced at the later stage of the separation process, with the frequency controlled in the low-frequency range of 5 Hz to 10 Hz.

[0061] When the low-frequency alternating magnetic field is applied, the direction and strength of the magnetic field change periodically, causing the magnetic particle clusters to be continuously and slightly disturbed and restructured. This breaks up larger, loosely structured magnetic flocs, exposing the internal droplets, which are then released under the action of gravity. This process effectively reduces the entrainment loss of the target product, further improving the yield.

[0062] Step (d): regenerating the separated functionalized magnetic nanoparticles loaded with pigments and returning the regenerated magnetic nanoparticles to step (b) for recycling.

[0063] The separated functionalized magnetic nanoparticles loaded with pigments are subjected to regeneration treatment to desorb the adsorbed pigments and impurities, restore their adsorption capacity, and return them to step (b) for recycling, thereby realizing the reuse of the adsorbent.

[0064] The regeneration process is to elute the magnetic nanoparticles using an ethanol aqueous solution as the eluent. As a polar organic solvent, the ethanol aqueous solution can effectively destroy the main binding force between the pigment molecules and the choline ionic liquid ligands on the surface of the functionalized magnetic nanoparticles. The concentration of ethanol in the eluent is between 50% and 60%.

[0065] Further, the elution operation is usually carried out under mild heating conditions, and the optimal temperature range is controlled between 45-55°C. Moderate heating provides additional energy, accelerates the desorption kinetics of the pigment molecules, and improves the elution rate and thoroughness.

[0066] The elution method can be carried out in a stirred tank in a batch mode, or more preferably, the pigment-loaded magnetic particles are packed into a column device, and the preheated ethanol aqueous solution is passed through the bed in a counter-current or cross-flow mode at a certain air speed. The empty tower flow rate is maintained in the range of 1.5-2.5 BV per hour to ensure sufficient contact time between the eluent and the particles, while maintaining good mass transfer efficiency. The end point of elution can be judged by monitoring the color or UV absorption value of the effluent. When the effluent becomes colorless or the UV absorption value decreases to the baseline, it indicates that the pigment has been basically eluted.

[0067] After the ethanol elution is completed, a certain amount of ethanol and a small amount of pigment fragments that may be eluted are left in the pores and on the surface of the particles. Therefore, a sufficient amount of deionized water is used for flushing to completely remove the residual ethanol solvent, so as to avoid its being brought into the next adsorption cycle, thereby changing the composition of the subsequent GMP water phase or affecting the adsorption equilibrium. Moreover, the surrounding environment of the magnetic nanoparticles is returned to the pure water phase state, and the surface properties thereof are restored to the initial hydrophilic state suitable for adsorbing pigments in the water phase, so that the adsorption performance is completely restored. The cleaning operation usually needs to be carried out for multiple times until the conductivity of the washing water approaches the background value of the deionized water.

[0068] After the regeneration treatment, the adsorption capacity of the functionalized magnetic nanoparticles can be restored to more than 98% of the initial value. Subsequently, these regenerated functionalized magnetic nanoparticles are transported back to the magnetic particle inlet 5 at the upper part of the magnetic stabilized fluidized bed adsorption tower, and are re-put into the next round of continuous countercurrent adsorption operation, so as to realize the recycling use of the adsorbent.

[0069] In summary, using an ethanol aqueous solution as the elution medium, supplemented with deionized water for cleaning, the regeneration and recovery of the adsorbent are efficiently realized under mild conditions.

[0070] Step (e): Post-treatment of the preliminarily decolorized GMP water phase to obtain a high-purity GMP product.

[0071] The deep purification of GMP aqueous phase after preliminary decolorization by countercurrent extraction mainly includes two core links: deep purification by series adsorption column and program-controlled crystallization. The residual trace impurities, homologues and salts are removed completely, and the product of high purity and regular crystal form is obtained by controllable crystallization, which meets the pharmaceutical or food grade standards.

[0072] The GMP aqueous phase after preliminary decolorization firstly enters the deep purification stage, which is completed by two series adsorption column systems. The first adsorption column is filled with macroporous adsorption resin. This kind of resin has pore structure and large specific surface area, which can efficiently adsorb and remove residual non-polar or weakly polar small molecular organic matter, pigment degradation products and part of the possible trace fermentation by-products in the aqueous phase.

[0073] Then, the effluent enters the second adsorption column, which is filled with high selectivity strong basic anion exchange resin. GMP molecules are negatively charged in near-neutral aqueous phase, which will be adsorbed by ion exchange with quaternary ammonium groups on the resin. The high resolution of ion exchange resin realizes the separation of GMP and residual charged impurities. Elution is carried out by pH or ionic strength gradient elution method, gradually increasing the concentration of eluent (such as sodium chloride solution), and the impurity ions with weak binding force are eluted first, then the target product GMP is selectively eluted at a specific ionic strength, and finally the strongly adsorbed impurities are removed, so as to realize the high-precision separation and purification of GMP.

[0074] After obtaining the GMP dilute solution with high purity, the purified GMP aqueous phase is sent into the program cooling crystallizer. Under mild stirring, 2% to 3% sodium chloride and 2% to 3% sodium phosphate are added as crystal form modifiers, which account for 2% to 3% of the mass of the aqueous phase. The addition of sodium chloride mainly reduces the solubility of GMP through the common ion effect, promoting crystallization. The phosphate ions of sodium phosphate may interact with specific groups on the GMP molecule, preferentially adsorbing on specific crystal faces, changing the relative growth rate of each crystal face, and thus inducing the formation of crystals with larger particles, more regular morphology, and more concentrated particle size distribution, effectively reducing phenomena such as crystal agglomeration and embedding of mother liquor.

[0075] Ethanol is used as the solventing agent in the crystallization process. Ethanol is completely miscible with water, which reduces the solubility of GMP in the mixed solvent system, thereby inducing supersaturation and driving crystallization. The addition of ethanol is carried out by program variable speed dropping. In the initial stage, the dropping speed is slow to avoid local supersaturation being too high, which may lead to explosive nucleation and generate a large number of fine crystals. As the crystal nuclei form, the dropping speed is appropriately increased, and then reduced again in the later stage to facilitate crystal growth. The whole dropping process is combined with program cooling, and the crystallization temperature starts from room temperature or a higher temperature, and slowly decreases to a lower final crystallization temperature according to the preset cooling rate. This controls the supersaturation of the system at a moderate level, which is conducive to obtaining an ideal product particle size distribution.

[0076] In summary, the post-treatment step realizes the deep purification and physical forming of the product by the combination of adsorption chromatography and crystallization technology.

[0077] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above-mentioned embodiments, and various changes and improvements can be made without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A process for the continuous countercurrent extraction decolorization of GMP, characterized in that, The method comprises the following steps: (a) providing a GMP crude product aqueous solution and performing pretreatment; (b) providing functionalized magnetic nanoparticles, continuously contacting the pretreated GMP aqueous phase with the functionalized magnetic nanoparticles in an extraction device to adsorb pigments on the magnetic nanoparticles, and obtaining a preliminarily decolorized GMP aqueous phase; (c) separating the functionalized magnetic nanoparticles loaded with pigments from the preliminarily decolorized GMP aqueous phase by applying a magnetic field; (d) regenerating the separated functionalized magnetic nanoparticles loaded with pigments and returning the regenerated magnetic nanoparticles to step (b) for recycling; (e) post-treating the preliminarily decolorized GMP aqueous phase to obtain a high-purity GMP product.

2. The GMP continuous counter current extraction decolorization process method according to claim 1, characterized in that, The pretreatment comprises irradiating the GMP crude product aqueous solution with a laser (7) having a wavelength in the visible light band and matching the characteristic absorption peak of the target pigment by a laser irradiation method; The laser irradiation method is completed immediately before the feed inlet of the extraction device.

3. The GMP continuous counter current extraction decolorization process method according to claim 2, characterized in that, Step (b) is performed in a magnetically stabilized fluidized bed adsorption tower; The tower body (1) of the magnetically stabilized fluidized bed adsorption tower is made of a non-magnetic material; At least one set of electromagnetic coils (2) is arranged around the outside of the tower body (1), and when energized, the electromagnetic coils (2) can generate a uniform-intensity axial static magnetic field in the internal cavity of the tower body (1) with a direction parallel to the axis of the tower body (1); The bottom of the tower body (1) is provided with a liquid distributor (3), the upper part of the tower body (1) is provided with a magnetic particle inlet (5), and the top is provided with a clear liquid overflow port (4); The average particle size of the magnetic nanoparticles is 20-50 nm.

4. The GMP continuous countercurrent extraction decolorization process method according to claim 3, wherein The number of electromagnetic coils (2) matches the number of extraction stages, and each set of electromagnetic coils (2) is independently sleeved on the outside of the tower body (1) corresponding to each tower plate; The electromagnetic coils (2) are Helmholtz coil pairs or solenoid coils; By independently regulating the current intensity of each set of electromagnetic coils (2), an axial magnetic field of 0.1-0.5 T is formed in the tower, and a magnetic field gradient along the tower height can be generated; The empty tower flow rate of the fluidized bed is maintained in the range of 0.5-2.0 cm / s, so that the functionalized magnetic nanoparticles form a stable dispersed fluidized bed layer under the joint action of the magnetic field and the fluid.

5. The GMP continuous counter current extraction decolorization process method according to claim 4, characterized in that, In step (c), the magnetic field is a static magnetic field; Or, a low-frequency alternating magnetic field with a frequency of 5-10 Hz is applied at the later stage of the separation stage to disturb the magnetic nanoparticle agglomerates and promote the release of entrained droplets.

6. The GMP continuous counter-current extraction decolorization process method according to claim 5, characterized in that, The inside of the magnetically stabilized fluidized bed adsorption tower is provided with a plurality of layers of horizontally arranged flow guides (6), which divide the space in the tower into a plurality of series of adsorption stage chambers; Each adsorption stage chamber corresponds to a set of external electromagnetic coils (2); The flow guide (6) is a perforated plate or screen with an opening rate of 40%-60% to allow fluid and magnetic nanoparticles to pass through; The opening areas on the flow guides (6) of adjacent layers are arranged in a staggered manner in the horizontal direction. The magnetic nanoparticles flow from top to bottom along a zigzag path under the joint guidance of a gradient magnetic field and a staggered flow guide (6), and realize sufficient multi-stage countercurrent contact with the GMP aqueous phase flowing from bottom to top.

7. The GMP continuous counter current extraction decolorization process method according to claim 5, characterized in that, In step (a), the pretreatment further comprises adjusting the pH of the GMP crude aqueous solution to 8.5-9.0, adjusting the temperature to 35-40 DEG C, and adding 3%-6% of sodium chloride and 0.01%-0.03% of beta-cyclodextrin based on the mass of the aqueous phase.

8. The GMP continuous counter current extraction decolorization process method according to claim 1, characterized in that, The functionalized magnetic nanoparticles comprise a superparamagnetic ferroferric oxide core, a silica isolation layer wrapping the core, and a choline ionic liquid ligand grafted on the isolation layer through chemical bonding.

9. The GMP continuous counter current extraction decolorization process method according to claim 1, characterized in that, In step (d), the regeneration treatment comprises eluting the pigment-loaded magnetic nanoparticles using an ethanol aqueous solution with a concentration of 50%-60%, followed by washing with deionized water.

10. The GMP continuous counter current extraction decolorization process method according to claim 1, characterized in that, In step (e), the post-treatment comprises: The preliminarily decolorized GMP aqueous phase is sequentially subjected to deep refining by passing through a first adsorption column filled with macroporous adsorption resin and a second adsorption column filled with high-selectivity anion exchange resin; The refined GMP aqueous phase is fed into a programmed temperature reduction crystallizer, programmed variable-speed ethanol is added dropwise as a solventing agent, and 2%-3% of sodium chloride and 2%-3% of sodium phosphate are added as crystal type modifiers based on the mass of the aqueous phase, so as to finally obtain high-purity GMP crystals.

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