Separation process of EPA-EE and DHA-EE

Abstract

The invention discloses a separation process of EPA-EE and DHA-EE, and relates to the technical field of separation and purification of polyunsaturated fatty acid ethyl ester. The invention discloses a separation process of EPA-EE and DHA-EE, which comprises the following steps: firstly, carrying out reflux reaction on deep sea crude fish oil by using absolute ethyl alcohol and strong base anion exchange resin, carrying out centrifugal separation, and collecting an oil phase; adding the oil phase into molecular distillation to obtain a raw material solution; performing chromatographic separation on the raw material solution to obtain an EPA-EE raffinate and a DHA-EE extract; and carrying out reduced pressure distillation on the EPA-EE raffinate and the DHA-EE extract, and concentrating to obtain dried EPA-EE and DHA-EE products. The EPA-EE and DHA-EE obtained by the separation process disclosed by the invention are detected by a nuclear magnetic resonance spectrometer and a gas chromatograph, and the purity of the products reaches 99%.

Description

Technical Field

[0001] The invention relates to the technical field of separation and purification of polyunsaturated fatty acid ethyl esters, and in particular to a separation process of EPA-EE and DHA-EE. Background Art

[0002] Deep-sea fish oil is rich in Omega-3 polyunsaturated fatty acids, the main components of which are EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). These fatty acids are essential fatty acids that cannot be synthesized by the human body but are essential for maintaining life activities. The total content of EPA and DHA in marine fish oil from natural sources is between 20% and 30%, and it also contains a large amount of saturated and monounsaturated fatty acids, which are inefficient components or impurities. Not only do they have no therapeutic effect, but they also increase the body's calorie intake after taking them. In addition, the active substances in them are easily oxidized and become rancid during the production process, making them difficult to preserve for a long time. Therefore, in industrial production, most manufacturers use technical means to convert fish oil into ethyl esters, and high-purity Omega-3 fatty acid esters can be obtained through further separation and treatment.

[0003] DHA plays an important role in promoting the growth and development of brain cells, improving brain function, improving memory and learning ability, enhancing retinal reflex ability and preventing Alzheimer's disease. It is a key nutrient for improving brain nerves and improving brain cognitive ability. EPA has the functions of reducing triglycerides and cholesterol in the human body, preventing thrombosis, etc., and helps to reduce the prevalence of cardiovascular diseases. At the same time, high-purity EPA-EE (eicosapentaenoic acid ethyl ester, EPA ethyl ester) has good compatibility with statin drugs and has disintegration properties in drug improvement, so it can be used as a drug adjuvant in the medical field. At present, Vascepa (96% purity, without DHA) produced by Amarin is the only EPA-type drug approved for marketing by the US FDA as an adjuvant for statin treatment. There are certain differences in the physiological functions of EPA and DHA, so it is of great significance to develop EPA-EE and EPA-EE preparation and separation technology.

[0004] At present, the catalysts for the transesterification reaction of enriching fish oil ethyl esters mainly include concentrated sulfuric acid, NaOH, KOH, sodium methoxide and other strong acidic or alkaline catalysts in addition to lipase. Although the reaction conditions of lipase catalysis are mild, the reaction time is long, and the transesterification reaction is not complete. The catalyst has the disadvantages of being difficult to separate and recover, polluting products and having more side reactions. At the same time, due to the similar structure and polarity of these two polyunsaturated fatty acid ethyl esters, it is difficult to separate them efficiently, completely, continuously and on a large scale. The commonly used separation methods are mainly chromatography, including high performance liquid chromatography, supercritical fluid chromatography, simulated moving bed chromatography, high speed countercurrent chromatography, etc. Simulated moving bed chromatography (SMB) is a new separation technology first developed in the petroleum industry in the 1960s, with the advantages of large processing capacity, high product purity, and low consumption of washing and dehydrating machines. Different from other chromatography, SMB can realize continuous operation, recycle the mobile phase, and reuse the stationary phase to meet the requirements of industrial production.

[0005] Chinese invention patent application publication number CN102964249 discloses a method for obtaining EPA ethyl ester and DHA ethyl ester by supercritical separation through sodium ethoxide alkaline catalyst catalyzed ethyl esterification and urea inclusion. The method needs to first remove free fatty acids, small molecule fatty acid ethyl esters and glycerides in fish oil by supercritical extraction and supercritical countercurrent extraction, and the enriched Omega-3 ethyl ester mixture is separated by supercritical distillation. However, the alkaline catalyst used in this method is not recyclable, and the ethyl esterification reaction needs to be completed and washed with water. There are many separation and purification steps, and the industrial production of supercritical extraction is difficult.

[0006] Chinese invention patent application publication number CN107311866A discloses a three-zone simulated moving bed chromatographic separation system for separating multi-component five-component ester fish oil, which can separate EPA ester and DHA ester at one time. However, this method separates impurities first and then separates EPA ester and DHA ester by controlling the operation and stop of pumps in each zone, and feeds intermittently. Different liquids need to be replaced in the middle, which is inefficient and the equipment is easy to wear, which is not conducive to large-scale production. Chinese invention patent application publication number CN104529772 A describes a traditional four-zone eight-column isothermal simulation using reverse phase resin as the stationary phase to separate EPA ester and DHA ester by moving bed chromatography, with a monomer purity of more than 95%. It is necessary to develop a traditional four-zone simulated moving bed chromatography that is both efficient and improves the purity of EPA ethyl ester and DHA ethyl ester without incurring the cost of equipment modification. Summary of the invention

[0007] The purpose of the present invention is to provide a separation process of EPA-EE and DHA-EE to solve the following technical problems:

[0008] The existing separation process of EPA-EE and DHA-EE has many separation and purification steps, and the supercritical extraction method is difficult to industrialize.

[0009] The purpose of the present invention can be achieved through the following technical solutions:

[0010] A separation process of EPA-EE and DHA-EE comprises the following steps:

[0011] S1: Add deep-sea crude fish oil, anhydrous ethanol and strong basic anion exchange resin into a reactor and heat it to reflux for 1-6 hours, centrifuge and collect the oil phase;

[0012] S2: adding the oil phase into the secondary molecular distillation feeder for primary distillation and secondary distillation, collecting the substances left from the evaporation surface after the secondary distillation to obtain a mixed concentrate;

[0013] S3: adding the mixed concentrate into the simulated moving bed chromatography system through the raw material port and the eluent through the eluent port, collecting the DHA-EE extract at the extract outlet of the simulated moving bed chromatography system and collecting the EPA-EE raffinate at the raffinate port;

[0014] S4: The EPA-EE raffinate and the DHA-EE extract are subjected to vacuum distillation and concentration to obtain EPA-EE and DHA-EE products respectively.

[0015] As a further solution of the present invention: the addition ratio of deep-sea crude fish oil, anhydrous ethanol and strong basic anion exchange resin in S1 is 1:0.10-0.15:0.01-0.05.

[0016] As a further solution of the present invention: the strong base anion exchange resin is a pretreated strong base anion exchange resin, and the specific steps of the pretreatment are: placing the strong base anion exchange resin in a mixed solution containing sodium hydroxide solution and potassium hydroxide solution for immersion activation treatment for 12-36 hours.

[0017] As a further solution of the present invention: the sodium hydroxide solution is 1 mol / L sodium hydroxide solution, and the potassium hydroxide solution is 1 mol / L potassium hydroxide solution; the volume ratio of the sodium hydroxide solution: the potassium hydroxide solution in the mixed solution is 1:1; and the volume ratio of the strong base anion exchange resin: the mixed solution is 1:1.

[0018] As a further solution of the present invention: the primary distillation conditions are: operating pressure 100 Pa, feed rate 0.2 L / min, evaporation temperature 60° C., and scraping speed 260 r / min.

[0019] As a further solution of the present invention: the secondary distillation conditions are: operating pressure 0.1 Pa, evaporation temperature 160° C., and scraping speed 210 r / min.

[0020] As a further solution of the present invention: the chromatographic system comprises 8-16 chromatographic columns connected in series, the chromatographic columns are C18 chromatographic columns, the chromatographic system is a silica matrix filler, the silica matrix filler comprises a silica skeleton and C4-C30 alkanes bonded to the surface of the silica skeleton, the particle size of the silica matrix filler is 10μm and the pore size is 1001.

[0021] As a further embodiment of the present invention: the eluent is anhydrous ethanol.

[0022] As a further embodiment of the present invention: the concentration of the mixed concentrated solution is 100 g / L.

[0023] As a further solution of the present invention: the operating parameters of the chromatography system include: a mixed concentrate feed flow rate of 1-5 mL / min, an eluent flow rate of 8-10 mL / min, a system temperature of 25° C., and a system pressure of 8 MPa.

[0024] As a further solution of the present invention: the simulated moving bed chromatography system is a four-zone eight-column simulated moving bed chromatography system, each zone is provided with two chromatographic columns, the switching time is 8 minutes, and the flow rate of each zone is: 10.0 mL / min in zone one, 6.8 mL / min in zone two, 5.5 mL / min in zone three, and 6.5 mL / min in zone four.

[0025] As a further solution of the present invention: the simulated moving bed chromatography system has two inlets and two outlets, the two inlets are respectively a raw material inlet and an eluent inlet, and the two outlets are respectively an extract outlet and a residual liquid outlet, all of which continuously flow out or flow in. The four inlets are divided into four zones, and the feed liquid inlet and the eluent inlet at different positions in the continuous loop along the same direction as the mobile phase are switched at fixed time intervals by a predetermined control switching time of a rotary valve, and the collection position outlets of the weakly adsorbed component EPA-EE and the strongly adsorbed component DHA-EE are also changed to move in the same direction, and the relative positions in the cycle are maintained to achieve reverse continuous flow / movement of the mobile phase, the stationary phase, and the raw material components.

[0026] Beneficial effects of the present invention:

[0027] (1) The present application discloses a process for preparing EPA ethyl ester and DHA ethyl ester using a green strong alkaline ion exchange resin catalyst, and separating EPA ethyl ester and DHA ethyl ester using a four-zone eight-column simulated moving bed chromatography system technology. The method reduces the feed liquid temperature to form a temperature gradient inside, thereby enhancing the adsorption capacity of zone III downstream of the feed port for DHA-EE, so that DHA-EE cannot approach the residual liquid extraction port and is relatively transferred to the upstream of the feed port as the columns are switched; under the elution of the eluent, EPA-EE is enriched with high purity downstream of the feed port as the eluent flows, thereby achieving separation of the two. The system temperature is always consistent and unchanged. After switching the inlets and outlets, the chromatographic column before the feed port becomes the position of the chromatographic column after the feed port. The temperature difference range between the system and the feed liquid is controlled, and the flow rates of each inlet and outlet are adjusted to eliminate the influence of the sudden change in the temperature of the chromatographic column upstream of the feed port as the column is switched. The upstream of the feed port always maintains a stable and high temperature, and the temperature gradient is maintained to achieve efficient analysis of the weakly adsorbed component EPA-EE in the upstream II zone of the feed port, and efficient desorption of the strongly adsorbed component DHA-EE in the upstream I zone. Under the column switching and eluent flow, the purpose of complete separation is achieved. EPA-EE flows out from the residual liquid port, and DHA-EE flows out from the extraction liquid port, reducing the solvent consumption and equipment loss. Finally, the EPA-EE residual liquid and DHA-EE extract are obtained, which are respectively subjected to reduced pressure distillation and concentration to obtain dry EPA-EE and DHA-EE products, and the recovered ethanol is used in the preparation or separation process. EPA-EE and DHA-EE are separated and tested by nuclear magnetic resonance spectrometer and gas chromatograph, and the product purity reaches more than 99%.

[0028] (2) By feeding the material through cold flow, a temperature gradient is formed inside the system, which enhances the adsorption or desorption capacity and efficiency of each zone. The temperature is indirectly changed by this external method, rather than directly modifying the entire chromatography system by using a heat exchanger. The operation is simple and easy to implement, and the system temperature is set close to room temperature, which reduces energy consumption and the complexity of the equipment, thus meeting general industrial production requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be further described below in conjunction with the accompanying drawings.

[0030] Figure 1 This is a schematic diagram of the operation of the four-zone eight-column simulated moving bed chromatography system used in this application;

[0031] Figure 2 is a gas chromatogram of EPA-EE separated in Example 2 of the present application;

[0032] Figure 3 is a gas chromatogram of DHA-EE separated in Example 2 of the present application;

[0033] Figure 4is the hydrogen nuclear magnetic resonance spectrum of EPA-EE separated in Example 2 of the present application;

[0034] Figure 5 This is the hydrogen-carbon nuclear magnetic resonance spectrum of EPA-EE separated in Example 2 of the present application;

[0035] Figure 6 This is the hydrogen nuclear magnetic resonance spectrum of DHA-EE separated in Example 2 of the present application;

[0036] Figure 7 This is the hydrogen-carbon nuclear magnetic resonance spectrum of DHA-EE separated in Example 2 of the present application. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Example 1 Please refer to Figure 1 , a separation process of EPA-EE and DHA-EE, comprising the following steps:

[0039] S1: 100mL 1mol / L sodium hydroxide solution and 100mL 1mol / L potassium hydroxide solution were mixed, and then 200mL DIAION porous PA 306 strong base anion exchange resin was added and immersed for activation for 24 hours, followed by rinsing three times with distilled water equal to the volume of the resin, and wiping off the surface moisture completely to fully remove organic and inorganic impurities in the ion exchange resin, thereby obtaining an activated strong base anion exchange resin;

[0040] S2: 10 g of deep-sea crude fish oil, 1.2 g of anhydrous ethanol, and 0.1 g of activated strong base anion exchange resin were added to a reactor and heated to 60° C., the mechanical speed was 800 rpm, refluxed for 1 h, and centrifuged (high-speed refrigerated centrifuge at 9400×g centrifugal force, 15° C. to separate the catalyst, oil phase, and alcohol phase), and the oil phase (mainly composed of polyunsaturated fatty acid ethyl esters) was collected. The alcohol phase was distilled under reduced pressure to recover ethanol, which can be used as a solvent raw material for the next batch of reactions;

[0041] S3: Add the oil phase into the secondary molecular distillation feeder, and perform primary distillation at an operating pressure of 100 Pa, a feed rate of 0.2 L / min, an evaporation temperature of 60°C, and a scraping speed of 260 r / min to remove water and small molecular impurities;

[0042] The secondary distillation is carried out at an operating pressure of 0.1 Pa, an evaporation temperature of 160°C, and a scraping speed of 210 r / min. The secondary distillation separates the light component distillate (light phase) such as short-chain fatty acids or ethyl esters and the EPA-EE and DHA-EE heavy component concentrate (heavy phase). The light phase is retained on the condensation surface, and the heavy phase flows down along the evaporation surface. The substances retained from the evaporation surface after the secondary distillation are collected to obtain a mixed concentrate.

[0043] S4: A four-zone eight-column simulated moving bed chromatography system was used. The columns were connected in series in a 1-2-2-1 mode. CAPCELL PAK C18 columns were used. The column size was 20 mm × 250 mm. Silica gel matrix filler was used. The particle size of the silica gel matrix filler was 10 μm and the pore size was 1001.

[0044] Among them, the setting parameters of the four-zone eight-column simulated moving bed chromatography system are as follows:

[0045]

[0046] Separation process: The system has two inlets and two outlets. The two inlets are the raw material inlet and the eluent inlet, and the two outlets are the extract outlet and the residual liquid outlet. The four inlets and outlets are divided into four zones with different functions. The bed is connected to the rotary valve through a pipeline. The switching time of the rotary valve is controlled by the program. The four inlets and outlets also move clockwise, that is, the direction of liquid flow, every 6 minutes to achieve reverse movement of the stationary phase and the mobile phase.

[0047] After the system starts to work for a period of time, the sample moves forward continuously under the flushing of the mobile phase, and the components in the sample begin to be partially separated slowly. The injection port and the outlet also move forward at the same time through the closing of the valve in the system, but the speed of movement and the time of each interval should always ensure that the injection point is in the interval range where the two components have not been separated and still overlap. Through the above parameter settings, optimize the interval time of each valve switching opening and closing, adjust the speed of the simultaneous forward movement of the inlet and outlet, and properly move the two inlets and outlets of the system at the same time to optimize the amount of solution entering and withdrawn per unit time at the two inlets and two outlets. When the system continues to work for a certain period of time, the mixture in the column will achieve a considerable degree of separation, and the concentration separation curve in the column can always be kept in an unchanged distribution state, so that continuous injection and continuous product can be obtained. At the same time, the two separated components of the product are continuously obtained at the two outlets of the system.

[0048] During the stable operation of the system, ethanol enters zone I through the eluent inlet, desorbs the strongly adsorbed component DHA-EE, so that DHA-EE flows out from the extract outlet to obtain DHA-EE extract, ensuring a high yield of DHA-EE. Zone II is between the extract outlet and the feed inlet, and zone III is between the feed inlet and the raffinate outlet. The separation of EPA-EE and DHA-EE mixture is completed in these two intervals. The easily adsorbed component DHA-EE moves slowly in the chromatographic column and slowly accumulates in zone II, while the EPA-EE component with weak adsorption capacity moves faster in the chromatographic column. The strongly adsorbed component DHA-EE replaces the EPA-EE weakly adsorbed component in zone II, so that EPA-EE is slowly concentrated in zone III and resolved in this interval to ensure the high purity of EPA-EE, so that it flows out from the raffinate outlet. The remaining weakly adsorbed component EPA-EE is adsorbed by the stationary phase in zone IV to prevent it from entering zone I and contaminating the raffinate, and ethanol can be recycled at the same time. During the process of continuous sampling and timed simultaneous switching of the inlet and outlet, ethanol enters zone I again to desorb the strongly adsorbed component DHA-EE, causing DHA-EE to flow out of the extract outlet again to obtain a regenerated DHA-EE extract, which is circulated back and forth. The extract outlet of the four-zone eight-column simulated moving bed chromatography system collects DHA-EE extract, and the raffinate outlet collects EPA-EE raffinate;

[0049] S5: The EPA-EE raffinate and the DHA-EE extract are subjected to vacuum distillation and concentration to obtain EPA-EE and DHA-EE products respectively.

[0050] Example 2 Please refer to Figure 1-7 , a separation process of EPA-EE and DHA-EE, comprising the following steps:

[0051] S1: 100mL 1mol / L sodium hydroxide solution and 100mL 1mol / L potassium hydroxide solution were mixed, and then 200mL DIAION porous PA 306 strong base anion exchange resin was added and immersed for activation for 24 hours, followed by rinsing three times with distilled water equal to the volume of the resin, and wiping off the surface moisture completely to fully remove organic and inorganic impurities in the ion exchange resin, thereby obtaining an activated strong base anion exchange resin;

[0052] S2: 10 g of deep-sea crude fish oil, 1.2 g of anhydrous ethanol, and 0.3 g of activated strong base anion exchange resin were added to a reactor and heated to 60°C, with a mechanical speed of 800 rpm, and refluxed for 3 h, and centrifuged (high-speed refrigerated centrifuge at 9400×g centrifugal force and 15°C temperature to separate the catalyst, oil phase, and alcohol phase), and the oil phase (mainly composed of polyunsaturated fatty acid ethyl esters) was collected, and ethanol was recovered from the alcohol phase by reduced pressure distillation, which can be used as a solvent raw material for the next batch of reactions;

[0053] S3: Add the oil phase into the secondary molecular distillation feeder, and perform primary distillation at an operating pressure of 100 Pa, a feed rate of 0.2 L / min, an evaporation temperature of 60°C, and a scraping speed of 260 r / min to remove water and small molecular impurities;

[0054] The secondary distillation is carried out at an operating pressure of 0.1 Pa, an evaporation temperature of 160°C, and a scraping speed of 210 r / min. The secondary distillation separates the light component distillate (light phase) such as short-chain fatty acids or ethyl esters and the EPA-EE and DHA-EE heavy component concentrate (heavy phase). The light phase is retained on the condensation surface, and the heavy phase flows down along the evaporation surface. The substances retained from the evaporation surface after the secondary distillation are collected to obtain a mixed concentrate.

[0055] S4: A four-zone eight-column simulated moving bed chromatography system was used. The columns were connected in series in a 1-2-2-1 mode. CAPCELL PAK C18 columns were used. The column size was 20 mm × 250 mm. Silica gel matrix filler was used. The particle size of the silica gel matrix filler was 10 μm and the pore size was 1001.

[0056] Among them, the setting parameters of the four-zone eight-column simulated moving bed chromatography system are as follows:

[0057]

[0058] The extract outlet of the four-zone eight-column simulated moving bed chromatography system collects DHA-EE extract, and the raffinate outlet collects EPA-EE raffinate;

[0059] S5: The EPA-EE raffinate and the DHA-EE extract are subjected to vacuum distillation and concentration to obtain EPA-EE and DHA-EE products respectively.

[0060] Example 3, please refer to Figure 1 , a separation process of EPA-EE and DHA-EE, comprising the following steps:

[0061] S1: 100mL 1mol / L sodium hydroxide solution and 100mL 1mol / L potassium hydroxide solution were mixed, and then 200mL DIAION porous PA 306 strong base anion exchange resin was added and immersed for activation for 24 hours, followed by rinsing three times with distilled water equal to the volume of the resin, and wiping off the surface moisture completely to fully remove organic and inorganic impurities in the ion exchange resin, thereby obtaining an activated strong base anion exchange resin;

[0062] S2: 10 g of deep-sea crude fish oil, 1.2 g of anhydrous ethanol, and 0.5 g of activated strong base anion exchange resin were added to a reactor and heated to 60° C., the mechanical speed was 800 rpm, refluxed for 6 h, and centrifuged (high-speed refrigerated centrifuge at 9400×g centrifugal force, 15° C. temperature to separate the catalyst, oil phase, and alcohol phase), and the oil phase (mainly composed of polyunsaturated fatty acid ethyl esters) was collected. The alcohol phase was distilled under reduced pressure to recover ethanol, which can be used as a solvent raw material for the next batch of reactions;

[0063] S3: Add the oil phase into the secondary molecular distillation feeder, and perform primary distillation at an operating pressure of 100 Pa, a feed rate of 0.2 L / min, an evaporation temperature of 60°C, and a scraping speed of 260 r / min to remove water and small molecular impurities;

[0064] The secondary distillation is carried out at an operating pressure of 0.1 Pa, an evaporation temperature of 160°C, and a scraping speed of 210 r / min. The secondary distillation separates the light component distillate (light phase) such as short-chain fatty acids or ethyl esters and the EPA-EE and DHA-EE heavy component concentrate (heavy phase). The light phase is retained on the condensation surface, and the heavy phase flows down along the evaporation surface. The substances retained from the evaporation surface after the secondary distillation are collected to obtain a mixed concentrate.

[0065] S4: A four-zone eight-column simulated moving bed chromatography system was used. The columns were connected in series in a 1-2-2-1 mode. CAPCELL PAK C18 columns were used. The column size was 20 mm × 250 mm. Silica gel matrix filler was used. The particle size of the silica gel matrix filler was 10 μm and the pore size was 1001.

[0066] Among them, the setting parameters of the four-zone eight-column simulated moving bed chromatography system are as follows:

[0067]

[0068] The extract outlet of the four-zone eight-column simulated moving bed chromatography system collects DHA-EE extract, and the raffinate outlet collects EPA-EE raffinate;

[0069] S5: The EPA-EE raffinate and the DHA-EE extract are subjected to vacuum distillation and concentration to obtain EPA-EE and DHA-EE products respectively.

[0070] Performance Testing

[0071] (1) Nuclear magnetic resonance spectrometer detection:

[0072] Take EPA-EE and DHA-EE respectively, add 5 mL of deuterated chloroform to dissolve the samples, and measure the hydrogen and carbon spectra of the dissolved samples by 500 MHz nuclear magnetic resonance spectrometer;

[0073] (2) Gas chromatography detection:

[0074] At a constant flow pressure of 30.8 psi, a CP-sil88 (100 m × 0.25 mm id, 0.2 μm) capillary column was used, N2 was used as the carrier gas, and the flow rate was set to 4.41 mL / min. 1 μL of sample was injected at a split ratio of 40:1, the injection port temperature was 250 °C, and the detector temperature was set to 270 °C. The heating program was: initial temperature 80 °C, then increased to 220 °C at 4 °C / min and maintained for 5 min, and then increased to 240 °C at 4 °C / min and maintained for 10 min. The purity of EPA-EE and DHA-EE was calculated by the area normalization method; the test results are shown in Table 1;

[0075] Table 1: Purity test data statistics of Examples 1-3

[0076] EPA-EE purity / % DHA-EE purity / % Example 1 99.12 99.24 Example 2 99.20 99.30 Example 3 99.13 99.26

[0077] As can be seen from Table 1, the EPA-EE and DHA-EE obtained by the separation process of the present application, when tested by nuclear magnetic resonance spectrometer and gas chromatograph, both products have reached a high purity of more than 99%.

[0078] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A separation process of EPA-EE and DHA-EE, characterized in that: The steps include: S1: Add deep-sea crude fish oil, anhydrous ethanol and strong basic anion exchange resin into a reactor and heat it to reflux for 1-6 hours, centrifuge and collect the oil phase; S2: adding the oil phase into the secondary molecular distillation feeder for primary distillation and secondary distillation, collecting the substances left from the evaporation surface after the secondary distillation to obtain a mixed concentrate; S3: adding the mixed concentrate into the simulated moving bed chromatography system through the raw material port and the eluent through the eluent port, collecting the DHA-EE extract at the extract outlet of the simulated moving bed chromatography system and collecting the EPA-EE raffinate at the raffinate port; S4: The EPA-EE raffinate and the DHA-EE extract are subjected to vacuum distillation and concentration to obtain EPA-EE and DHA-EE products respectively.

2. A separation process of EPA-EE and DHA-EE according to claim 1, characterized in that: The addition ratio of deep-sea crude fish oil, anhydrous ethanol and strong basic anion exchange resin in S1 is 1:0.10-0.15:0.01-0.

05.

3. A separation process of EPA-EE and DHA-EE according to claim 1, characterized in that: The strong base anion exchange resin is a pretreated strong base anion exchange resin, and the specific steps of the pretreatment are: placing the strong base anion exchange resin in a mixed solution containing sodium hydroxide solution and potassium hydroxide solution for immersion activation treatment for 12-36 hours.

4. A separation process of EPA-EE and DHA-EE according to claim 1, characterized in that: The primary distillation conditions are: operating pressure 100 Pa, feed rate 0.2 L / min, evaporation temperature 60° C., and scraping speed 260 r / min.

5. A separation process of EPA-EE and DHA-EE according to claim 1, characterized in that: The secondary distillation conditions are: operating pressure 0.1 Pa, evaporation temperature 160° C., and scraping speed 210 r / min.

6. A separation process of EPA-EE and DHA-EE according to claim 1, characterized in that: The chromatographic system comprises 8-16 chromatographic columns connected in series, wherein the chromatographic columns are C18 chromatographic columns, and the chromatographic system is a silica-based filler, wherein the silica-based filler comprises a silica-based skeleton and C4-C30 alkanes bonded to the surface of the silica-based skeleton, and the particle size of the silica-based filler is 10 μm and the pore size is 1001.

7. A separation process of EPA-EE and DHA-EE according to claim 1, characterized in that: The eluent is anhydrous ethanol.

8. A separation process of EPA-EE and DHA-EE according to claim 1, characterized in that: The concentration of the mixed concentrated solution is 100 g / L.

9. A separation process of EPA-EE and DHA-EE according to claim 1, characterized in that: The operating parameters of the chromatography system include: mixed concentrate feed flow rate of 1-5 mL / min, eluent flow rate of 8-10 mL / min, system temperature of 25° C., and system pressure of 8 MPa.

10. A separation process of EPA-EE and DHA-EE according to claim 1, characterized in that: The simulated moving bed chromatography system is a four-zone eight-column simulated moving bed chromatography system, with two chromatographic columns arranged in each zone, a switching time of 8 minutes, and flow rates in each zone: 10.0 mL / min in zone one, 6.8 mL / min in zone two, 5.5 mL / min in zone three, and 6.5 mL / min in zone four.

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