Liquid separation system

Abstract

The present invention provides a liquid separation system which is capable of quickly and efficiently performing a liquid separation operation.　According to the present invention, there is provided a liquid separation system which comprises a storage part, a magnetism application part, and a separation part. The storage part is configured so as to store a first solvent which is a non-polar solvent and a second solvent which is a polar solvent. The magnetism application part is configured so as to impart magnetism to one of the first solvent and the second solvent by supplying magnetic nanoparticles that can be dispersed in one of the first solvent and the second solvent, thereby forming the one of the solvents into a magnetic fluid. The separation part is configured so as to separate the first solvent and the second solvent in the storage part by means of a magnetic force. The magnetic nanoparticles are modified with a surface modifier which is composed of a compound having a phosphonic acid group, an isocyanate group, a carboxy group, an alcohol group, a thiol group, or an amino group.

Description

Separation System

[0001] The present invention relates to a liquid separation system capable of separating two solvents.

[0002] A separation operation may be performed to separate by-products (impurities, etc.) from the main product (target substance) produced in a chemical reaction. For example, in a separation operation, the main product is placed in one of two immiscible solvents, and the by-product is placed in the other, and the two solvents are then suitably separated, which makes it possible to recover the desired main product.

[0003] Patent Document 1 discloses a technique in which an interface between two solvents is automatically detected by a sensor, and a valve is automatically operated based on the detection result of the sensor to switch the flow path.

[0004] Patent No. 4157193

[0005] However, when an emulsion is formed between two solvents that are not easily miscible with each other, it can take a considerable amount of time for a clear interface to form. In such cases, there is the inconvenience that the separation operation cannot be carried out efficiently. Furthermore, even when the weight difference between the two solvents is small, a clear interface may not be obtained, which can cause problems in the separation operation.

[0006] The present invention has been made in view of the above circumstances, and provides a liquid separation system that can perform liquid separation operations quickly and efficiently.

[0007] According to the present invention, the following inventions are provided: [1] A liquid separation system including a storage unit, a magnetism imparting unit, and a separation unit, wherein the storage unit is configured to store a first solvent that is a nonpolar solvent and a second solvent that is a polar solvent, the magnetism imparting unit is configured to supply magnetic nanoparticles dispersible in one of the first solvent or the second solvent to impart magnetism to the first solvent or the second solvent to turn it into a magnetic fluid, the separation unit is configured to separate the first solvent and the second solvent in the storage unit by magnetic force, and the magnetic nanoparticles are modified with a surface modifier consisting of a compound having a phosphonic acid group, an isocyanate group, a carboxy group, an alcohol group, a thiol group, or an amino group. [2] The liquid separation system according to [1], wherein the magnetism imparting unit is configured to turn the first solvent into a magnetic fluid. [3] The liquid separation system according to [1] or [2], wherein the first solvent is cyclohexane, hexane, heptane, MTBE (methyl tert-butyl ether), N,N-dimethylformamide, tetrahydrofuran, toluene, dichloromethane, chloroform, cyclopentyl methyl ether, ethyl acetate, or N-methylpyrrolidone, and the second solvent is acetonitrile, DMF (N,N-dimethylformamide), DMSO (dimethyl sulfoxide), methanol, ethanol, propanol, acetone, or water. [4] The liquid separation system according to any one of [1] to [3], wherein the surface modifier is an alkylphosphonic acid or an alkenylphosphonic acid. [5] The liquid separation system according to [4], wherein the alkylphosphonic acid or the alkenylphosphonic acid has 10 or more carbon atoms. [6] The liquid separation system according to [4], wherein the number of carbon atoms in the alkylphosphonic acid or the alkenylphosphonic acid is 14 or more. [7] The liquid separation system according to any one of [1] to [6], wherein the solute of the first solvent is a target substance of a chemical reaction, and the solute of the second solvent is a contaminant produced during the chemical reaction.

[0008] In the liquid separation system of the present invention, the magnetic nanoparticles are surface-modified with a surface modifier consisting of a compound having a phosphonic acid group, an isocyanate group, a carboxyl group, an alcohol group, a thiol group, or an amino group, which can strongly adsorb to the surface of the magnetic nanoparticles, thereby preventing aggregation of the magnetic nanoparticles in the solvent. Therefore, by suitably dispersing the magnetic nanoparticles in either the first solvent (nonpolar solvent) or the second solvent (polar solvent), the solvent can be made into a magnetic fluid. The behavior of the magnetic fluid-modified solvent can be controlled by magnetic force, allowing for rapid and efficient liquid separation operations.

[0009] 1 is a schematic diagram of a separation system 1 according to an embodiment of the present invention. It is a diagram showing the state in which the magnetic fluid in the separation tank 2 is pulled down to the bottom by the magnetic force of the separation unit 4A. It is a diagram showing the state in which the magnetic fluid in the separation tank 2 is pulled up to the liquid surface by the magnetic force of the separation unit 4B. FIG. 4A shows an outline of magnetic nanoparticles, FIG. 4B shows the state in which the magnetic nanoparticles are dispersed in cyclohexane, and FIG. 4C shows the state in which the magnetic fluidized cyclohexane and acetonitrile are separated. FIG. 5A shows the interface state when the concentration of magnetic nanoparticles is 5.0 mg / mL, FIG. 5B shows the interface state when the concentration of magnetic nanoparticles is 3.0 mg / mL, FIG. 5C shows the interface state when the concentration of magnetic nanoparticles is 2.0 mg / mL, FIG. 5D shows the interface state when the concentration of magnetic nanoparticles is 1.0 mg / mL, FIG. 5E shows the interface state when the concentration of magnetic nanoparticles is 0.5 mg / mL, and FIG. 5F shows the interface state when the concentration of magnetic nanoparticles is 0.1 mg / mL. FIG. 6A shows the interface state (separation results) when cyclohexane is used as the first solvent and acetonitrile is used as the second solvent when an alkylphosphonic acid having 14 carbon atoms is used as the surface modifier. FIG. 6B shows the interface state when hexane is used as the first solvent and acetonitrile is used as the second solvent. FIG. 6C shows the interface state when heptane is used as the first solvent and acetonitrile is used as the second solvent. FIG. 6D shows the interface state when cyclohexane is used as the first solvent and DMF (N,N-dimethylformamide) is used as the second solvent. FIG. 6E shows the interface state when hexane is used as the first solvent and DMF is used as the second solvent. FIG. 6F shows the interface state when heptane is used as the first solvent and DMF is used as the second solvent.FIG. 7A shows the interface state (separation results) when cyclohexane is used as the first solvent and DMSO (dimethyl sulfoxide) is used as the second solvent when an alkylphosphonic acid having 14 carbon atoms is used as the surface modifier. FIG. 7B shows the interface state when hexane is used as the first solvent and DMSO is used as the second solvent. FIG. 7C shows the interface state when cyclohexane is used as the first solvent and methanol is used as the second solvent. FIG. 7D shows the interface state when hexane is used as the first solvent and methanol is used as the second solvent. FIG. 7E shows the interface state when heptane is used as the first solvent and methanol is used as the second solvent. FIG. 8A shows the interface state (separation results) when cyclohexane was used as the first solvent and acetonitrile was used as the second solvent, and an alkylphosphonic acid having 6 carbon atoms was used as the surface modifier. FIG. 8B shows the interface state when an alkylphosphonic acid having 10 carbon atoms was used as the surface modifier. FIG. 8C shows the interface state when an alkylphosphonic acid having 18 carbon atoms was used as the surface modifier. FIG. 8D shows the interface state when a carboxylic acid having 14 carbon atoms was used as the surface modifier. FIG. 8E shows the interface state when oleic acid was used as the surface modifier. FIG. 8F shows the interface state when a saturated alkylamine having 14 carbon atoms was used as the surface modifier.

[0010] The following describes embodiments of the present invention. The various features shown in the following embodiments can be combined with each other. Furthermore, each feature can be an independent invention.

[0011] <Overall Configuration of Separation System 1> As shown in FIG. 1 , the separation system 1 includes a separation tank 2, magnetism imparting units 3A and 3B, separation units 4A and 4B, a first solvent tank 5A, a second solvent tank 5B, a heater 6, a first receiving tank 7A, a second receiving tank 7B, a stirring device 8, automatic valves 9A to 9C, and a control unit 10.

[0012] Separation tank 2 is a separation tank that contains a first solvent, which is a nonpolar solvent, and a second solvent, which are poorly miscible with each other. Separation tank 2 corresponds to the storage section of the present invention. Furthermore, when a chemical reaction is carried out in separation tank 2, separation tank 2 also functions as a reaction tank. In this embodiment, the first solvent contained in separation tank 2 is cyclohexane, and the second solvent is acetonitrile, but the combination is not limited to this.

[0013] A discharge port 2A is provided at the bottom of the separation tank 2. The discharge port 2A is connected to a pipeline 90 via an automatic valve 9A. The ends of the pipeline 90 are connected to a first receiving tank 7A and a second receiving tank 7B via automatic valves 9B and 9C, respectively.

[0014] The magnetism imparting unit 3A is configured to impart magnetism to the first solvent by supplying magnetic nanoparticles dispersible in the first solvent, thereby converting it into a magnetic fluid. The magnetic nanoparticles used in the magnetism imparting unit 3A are preferably surface-modified to exhibit hydrophobicity. Similarly, the magnetism imparting unit 3B is configured to impart magnetism to the second solvent by supplying magnetic nanoparticles dispersible in the second solvent, thereby converting it into a magnetic fluid. The magnetic nanoparticles used in the magnetism imparting unit 3B are preferably surface-modified to exhibit hydrophilicity.

[0015] The separation units 4A, 4B are configured to separate the first solvent and the second solvent in the separation tank 2 by magnetic force. More specifically, the separation units 4A, 4B are configured to attract, by magnetic force, one of the first solvent and the second solvent in the separation tank 2 that has been made into a magnetic fluid. The separation units 4A, 4B may be configured to selectively generate a magnetic field by electrical control, for example, or may be configured to selectively bring a magnet close to the separation tank 2.

[0016] The first solvent tank 5A is configured to store the first solvent to be supplied to the separation tank 2. Examples of the first solvent stored in the first solvent tank 5A include, in addition to the above-mentioned cyclohexane, non-polar solvents such as hexane, heptane, MTBE (methyl tert-butyl ether), N,N-dimethylformamide, tetrahydrofuran, toluene, dichloromethane, chloroform, cyclopentyl methyl ether, ethyl acetate, and N-methylpyrrolidone.

[0017] The second solvent tank 5B is configured to store the second solvent to be supplied to the separation tank 2. Examples of the second solvent stored in the second solvent tank 5B include polar solvents such as acetonitrile, as well as N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), methanol, ethanol, propanol, acetone, and water.

[0018] The heater 6 is configured to selectively heat the mixed liquid in the separation tank 2. For example, when heating is required for a chemical reaction in the mixed liquid in the separation tank 2, the heater 6 can heat the mixed liquid in the separation tank 2 to a desired set temperature (for example, 50°C to 100°C).

[0019] The first receiving tank 7A is configured to receive the first solvent recovered by the separation operation in the separation tank 2. The second receiving tank 7B is configured to receive the second solvent recovered by the separation operation in the separation tank 2.

[0020] The stirring device 8 includes a motor 8A and a stirring member 8B. The stirring member 8B is rotationally driven by the motor 8A. The stirring by the stirring member 8B promotes a reaction in the mixed liquid in the separation tank 2. The control unit 10 is configured to comprehensively control the operation of each unit of the separation system 1.

[0021] <Magnetism Imparting Units 3A, 3B> As described above, the magnetism imparting unit 3A is configured to magnetize the first solvent, and the magnetism imparting unit 3B is configured to magnetize the second solvent. In this embodiment, the magnetism imparting unit 3A supplies magnetic nanoparticles to the first solvent before it is supplied to the separation tank 2. Iron oxide, iron, cobalt, nickel, etc. can be suitably used as the material for the magnetic nanoparticles. Furthermore, the surfaces of the magnetic nanoparticles supplied to the first solvent are modified with a surface modifier to improve dispersibility in the first solvent. Because the first solvent is a non-polar solvent, the surfaces of the magnetic nanoparticles are modified to exhibit hydrophobicity.

[0022] The magnetic nanoparticles used in this embodiment are modified with a surface modifier consisting of a compound having a phosphonic acid group, an isocyanate group, a carboxy group, an alcohol group, a thiol group, or an amino group. These compounds have been confirmed to exhibit strong adsorption to iron oxide surfaces. Furthermore, these compounds are expected to exhibit strong adsorption not only to iron oxide, but also to the surfaces of iron, cobalt, nickel, and the like. It is important that the surface modifier has properties that allow it to adhere strongly to the magnetic nanoparticles and not peel off, and that even if it does peel off, it does not become a hindrance to the chemical reaction.

[0023] When phosphonic acid groups, isocyanate groups, carboxy groups, or amino groups are bonded to organic substances of a certain length (e.g., alkyl or alkenyl groups with approximately 10 to 24 carbon atoms), they can become surface modifiers that exhibit an aggregation-inhibiting effect in nonpolar solvents using steric hindrance as a repulsive force. On the other hand, in order for a surface modifier to achieve an aggregation-inhibiting effect in a polar solvent, it is preferable to use the Coulomb force generated by charging the magnetic nanoparticle surface as the repulsive force. Furthermore, polyethylene glycol (PEG) or the like can be used to impart water-dispersibility to the magnetic nanoparticles.

[0024] The magnetism imparting unit 3A is equipped with, for example, an ultrasonic generator (not shown) and is configured to impart ultrasonic waves to the first solvent in order to favorably disperse the magnetic nanoparticles supplied to the first solvent in the first solvent. The basic configuration of the magnetism imparting unit 3B is the same as that of the magnetism imparting unit 3A. When the first solvent is made into a magnetic fluid as in this embodiment, the magnetism imparting unit 3B is an optional component and therefore does not need to be provided.

[0025] <Operation of Separation System 1> Here, an example is described in which magnetic fluidized cyclohexane is introduced into the separation tank 2 to carry out a chemical reaction, and by-products (impurities, etc.) produced by the chemical reaction are removed using acetonitrile. Cyclohexane and acetonitrile do not mix with each other and form two phases. Highly hydrophobic compounds selectively dissolve in cyclohexane. On the other hand, highly polar compounds selectively dissolve in acetonitrile.

[0026] First, cyclohexane in the first solvent tank 5A is sent to the magnetism imparting unit 3A. Then, in the magnetism imparting unit 3A, magnetic nanoparticles (e.g., iron oxide Fe) whose surfaces have been modified with a surface modifier having a phosphonic acid group (e.g., saturated alkylphosphonic acid having 14 carbon atoms) are mixed. ３ O ４ ) is fed into cyclohexane. Ultrasonic waves are then applied to uniformly disperse the magnetic nanoparticles in the cyclohexane. The uniform dispersion of the magnetic nanoparticles turns the cyclohexane into a magnetic fluid.

[0027] The magnetic fluidized cyclohexane is sent to the separation tank 2. Because cyclohexane is a non-polar solvent, chemical reactions in which a hydrophobic substance is the target substance can be suitably carried out in cyclohexane. Examples of chemical reactions include synthesis reactions such as liquid-phase peptide (amino acid) synthesis, nucleic acid (nucleotide) synthesis, peptide nucleic acid synthesis, and low molecular weight compound synthesis. As described below, the usefulness of the separation operation involving the separation system 1 in liquid-phase peptide synthesis has been confirmed. The separation operation involving the separation system 1 is not limited to this, but is also thought to be applicable to chemical reactions of low molecular weight molecules, nucleic acid synthesis of medium molecular weight molecules, and general separation operations of two poorly miscible liquids that are emulsified in fields such as fine chemicals.

[0028] After the desired chemical reaction has progressed in the separation tank 2, the acetonitrile in the second solvent tank 5B is sent to the separation tank 2. The mixture of cyclohexane and acetonitrile is thoroughly stirred by the stirrer 8, and then the stirrer 8 is stopped. Next, the cyclohexane and acetonitrile in the separation tank 2 are separated by the magnetic force of the separation unit 4A. Here, the magnetic fluid cyclohexane is attracted to the bottom of the separation tank 2 by the magnetic force of the separation unit 4A, as shown in FIG. 2 . As a result, the acetonitrile is pushed up toward the liquid surface.

[0029] Even when cyclohexane and acetonitrile form an emulsion in separation tank 2, the cyclohexane and acetonitrile are effectively separated by the action of magnetic force, as shown in Figure 2. In this state, by opening automatic valves 9A and 9B, cyclohexane containing the target substance can be recovered from discharge port 2A at the bottom of separation tank 2 into first receiving tank 7A.

[0030] Alternatively, the magnetic force of the separation unit 4B can be used to separate cyclohexane and acetonitrile in the separation tank 2. As shown in Figure 3, the magnetic force of the separation unit 4B can be used to pull up the magnetically converted cyclohexane toward the liquid surface. In this case, the acetonitrile is pushed down toward the bottom. In this state, by opening the automatic valves 9A and 9C, the acetonitrile containing impurities can be recovered from the discharge port 2A at the bottom of the separation tank 2 into the second receiving tank 7B.

[0031] In either case shown in Figure 2 or Figure 3, cyclohexane and acetonitrile are not easily miscible with each other, and the main product is present in cyclohexane, and the by-product is present in acetonitrile, allowing for a suitable separation operation. This makes it possible to quickly recover the desired main product and quickly remove impurities. While the example in which cyclohexane and acetonitrile are separated into liquid phases in the vertical direction has been described, cyclohexane and acetonitrile may also be separated into liquid phases in the horizontal direction. In this case, it is preferable to provide the discharge port 2A on the left or right side of the separation tank 2.

[0032] Phosphonic acid and carboxylic acid (particularly phosphonic acid and oleic acid) are expected to have strong adsorption power to iron oxide. Therefore, by using these acids, it is possible to obtain magnetic nanoparticles of iron oxide with stable surface modification. Such magnetic nanoparticles can be easily dispersed in a desired solvent using ultrasound or the like, thereby obtaining a magnetic fluid with good dispersibility. Therefore, they tend to function favorably as a dispersant for converting a desired solvent into a magnetic fluid.

[0033] <Dispersibility of Magnetic Nanoparticles> As shown in Figures 4A and 4B, we attempted to surface-modify iron oxide nanoparticles with saturated alkylphosphonic acids (C10, C14, and C18) and oleylphosphonic acid. Iron oxide nanoparticles modified with saturated alkylphosphonic acid (C14) and oleylphosphonic acid were confirmed to be highly dispersible in cyclohexane. Furthermore, when a 200 mT magnetic force was applied to the cyclohexane solution containing the iron oxide nanoparticles using a neodymium magnet, the dispersed magnetic nanoparticles maintained their dispersibility without being magnetically attracted. As shown in Figure 4C, when the magnet was moved, the cyclohexane moved in the intended direction as a magnetic fluid. Figure 4C shows a clear interface between cyclohexane on the left and acetonitrile on the right. This suggests that cyclohexane containing dispersed magnetic nanoparticles exhibits excellent magnetic separation properties from acetonitrile. Even when emulsions form between cyclohexane and acetonitrile, the cyclohexane and acetonitrile separated from each other within a few seconds when a magnet was brought close.

[0034] Figures 5A to 5F show the phase separation behavior after magnetization when using a saturated alkylphosphonic acid with 14 carbon atoms. The mass concentration of iron oxide nanoparticles modified with this alkylphosphonic acid in cyclohexane is indicated at the top of each figure. Since saturated alkylphosphonic acid with 14 carbon atoms is a commercially available product and is expected to be useful for future scale-up, we investigated the concentration dependence of iron oxide nanoparticles modified with this phosphonic acid. As shown in Figures 5A to 5F, even at concentrations below 1.0 mg / mL of magnetic nanoparticles, a clear interface was observed between the magnetic fluid-formed cyclohexane and acetonitrile, demonstrating that the nanoparticles were capable of fully performing their intended function.

[0035] The separated acetonitrile phase was almost colorless and transparent, and the cyclohexane phase containing the iron oxide nanoparticles was firmly retained in the separatory vessel. However, at a concentration of 0.5 mg / mL, the cyclohexane phase showed a slightly weak response to a magnet, possibly due to the magnetic insufficiency of the cyclohexane phase.

[0036] Other Embodiments In the above-described embodiment, an example was described in which the magnetic nanoparticles were modified with a surface modifier having a phosphonic acid group, but the surface modifier is not limited to this. A similar effect of improving dispersibility can be expected even if a compound having an isocyanate group or a carboxy group, which has a proven track record as a dispersant for suitably dispersing magnetic nanoparticles, is used as a surface modifier.

[0037] As the surface modifier, it is possible to use a phosphonic acid other than a saturated alkylphosphonic acid having 14 carbon atoms. For example, it is also possible to use an alkylphosphonic acid or alkenylphosphonic acid having a different number of carbon atoms. In this case, the alkylphosphonic acid or alkenylphosphonic acid preferably has 10 or more carbon atoms, and more preferably has 14 or more carbon atoms. The upper limit of the number of carbon atoms in the alkylphosphonic acid or alkenylphosphonic acid is preferably about 24, and more preferably 18. Note that if good dispersibility cannot be obtained at room temperature, dispersibility may be improved by appropriate heating.

[0038] Below, we will use Figures 6A to 6F, 7A to 7E, and 8A to 8F to demonstrate that good separation results can be obtained even when the first solvent, second solvent, and surface modifier are appropriately changed. Each figure shows a 3 mg / mL dispersion of iron oxide nanoparticles in 10 mL of the first solvent, to which 10 mL of the second solvent was added to form a mixed solvent system. After manual shaking, a neodymium magnet (200 mT) was brought close to the mixture from the side. In the tables, DMF stands for N,N-dimethylformamide, and DMSO stands for dimethyl sulfoxide.

[0039]

[0040] As shown in Figures 6B to 6F and Figures 7A to 7E, even when a solvent other than cyclohexane is used as the first solvent and a solvent other than acetonitrile is used as the second solvent, separation results that are comparable to those obtained in the case of Figure 6A, in which cyclohexane is used as the first solvent and acetonitrile is used as the second solvent.

[0041] 8A, a relatively good separation state is achieved even when a saturated alkylphosphonic acid having six carbon atoms is used as the surface modifier. However, for more reliable separation, it is preferable to use a saturated alkylphosphonic acid having ten or more carbon atoms as the surface modifier (see FIGS. 8B and 8C). Furthermore, a relatively good separation state is also achieved when a carboxylic acid having fourteen carbon atoms, oleic acid, and a saturated alkylamine having fourteen carbon atoms are used as the surface modifier (see FIGS. 8D to 8F).

[0042] As an example of applying the separation operation of the separation system 1, a tag-assisted liquid-phase peptide synthesis (TAG) method using a hydrophobic liquid-phase peptide synthesis support (TAG) will be described. The TAG liquid-phase method involves three reactions: <1. Introduction of an amino acid into the TAG>, <2. Deprotection reaction of the Fmoc protecting group>, and <3. Peptide elongation reaction>. In the introduction of an amino acid into the TAG (also referred to as the tagging reaction), the first amino acid is bonded to the hydrophobic TAG. Subsequently, in the deprotection reaction of the Fmoc (9-fluorenylmethoxycarbonyl) protecting group, the protecting group of the amino acid is removed. In the peptide elongation reaction, the next amino acid is bonded. The deprotection reaction of the Fmoc protecting group and the peptide elongation reaction are repeated as appropriate, but by-products (contaminants, etc.) are generated during these reactions. In the following, by-products (impurities, etc.) are efficiently removed by utilizing the properties that the highly hydrophobic main product (target substance) selectively dissolves in cyclohexane and the highly polar by-products (impurities, etc.) selectively dissolves in acetonitrile.

[0043] <1. Introduction of Amino Acid into TAG> The chemical reaction formula for introducing an amino acid into TAG is as follows: In the experiment, a 100 mL recovery flask was used as a reaction vessel. 5.0 mL of toluene was added to 0.30 mmol of TAG (molecular weight = 913.7), i.e., 274.1 mg of TAG, and the mixture was heated until the TAG was dissolved.

[0044] Subsequently, Fmoc-protected leucine, N,N'-diisopropylcarbodiimide (DIPCI), and 4-dimethylaminopyridine (DMAP) were added and stirred for 1 hour. The amounts used were as follows: Fmoc-protected leucine (molecular weight = 353.3): 1.1 equivalents, 0.33 mmol (116.6 mg); DIPCI (density 0.82 g / mL, molecular weight = 126.2): ​​1.6 equivalents, 0.48 mmol (60.6 mg, 73.9 μL); DMAP (molecular weight = 122.17): 0.2 equivalents, 0.060 mmol (7.3 mg).

[0045] After stirring for 1 hour, the reaction was monitored by thin layer chromatography (TLC) to confirm that the reaction had progressed. Then, 30.0 mL of acetonitrile (molecular weight = 41.05, density 0.786 g / mL) was added, the solvent was removed, and the white precipitate was collected by suction filtration.

[0046] <2. Deprotection Reaction of Fmoc Protecting Group> The chemical reaction formula for the Fmoc deprotection reaction is as follows: Here, a 100 mL Chemist Plaza container was used as the reaction container. First, cyclohexane, magnetic nanoparticles, and tagged leucine with an Fmoc protecting group were mixed and stirred with ultrasonic waves to disperse the magnetic particles. Here, the bottom side of the Chemist Plaza container was immersed in water in an ultrasonic cleaner to apply sufficient ultrasonic vibrations. The amounts used were as follows: Cyclohexane (molecular weight = 84.16): 5.0 mL Magnetic nanoparticles (iron oxide (Fe) with a particle diameter of about 10 nm) ３ O ４ ) surface-modified with saturated alkylphosphonic acid having 14 carbon atoms): 50 mg dispersed in 5.0 mL of cyclohexane. TAG-modified leucine with an Fmoc protecting group (molecular weight = 1249): 0.50 mmol (624.5 mg). The magnetic particle concentration here is 5.0 mg / mL.

[0047] After dispersing the magnetic particles in cyclohexane, the solution was heated to 50°C, and 4.0 equivalents of 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) (molecular weight = 152.24, density 1.02 g / mL), i.e., 2.0 mmol (304.5 mg, 298.5 μL), was added and stirred for 5 minutes. The reaction was monitored by TLC, and after confirming that the reaction had progressed, 10 mL of an acetonitrile / cyclohexane (10:1 (V / V)) solution was added and washed.

[0048] After stirring for 1 minute, the cyclohexane and acetonitrile were separated into liquid phases (liquid separation treatment) using a neodymium magnet with a magnetic field of 200 mT, and the acetonitrile was removed. After that, 10 mL of an acetonitrile / cyclohexane (10:1 (V / V)) solution was added again in the same way to wash the mixture, and a small amount of the washed solution was saved for TLC.

[0049] <3. Peptide elongation reaction> The chemical reaction formula of the peptide elongation reaction is as follows: Again, a 100 mL Chemist Plaza vessel was used as the reaction vessel. After the deprotection reaction, the cyclohexane solution was heated to 50°C, and then acetonitrile, phenylalanine with an Fmoc protecting group, (1-cyano-2-ethoxy-2-oxoethylideneaminooxy)dimethylamino-morpholino-carbenium hexafluorophosphate (COMU), and N,N-diisopropylethylamine (DIPEA) were added and stirred for 20 minutes. The amounts used were as follows: Acetonitrile: 10 mL (cyclohexane saturated) Fmoc-protected phenylalanine (molecular weight = 387.4): 2.0 equivalents, 1.0 mmol (387.4 mg) COMU (molecular weight = 428.3): 2.0 equivalents, 1.0 mmol (428.3 mg) DIPEA (molecular weight = 129.24, density 0.76 g / mL): 4.0 equivalents, 2.0 mmol (258.5 mg, 340.1 μL) Here, COMU is a condensing agent that can simultaneously activate a carboxylic acid and convert it to an activated ester using a condensation auxiliary.

[0050] Thereafter, the reaction was monitored by TLC, and after confirming that the reaction had progressed, 10 mL of an acetonitrile / cyclohexane (10:1 (V / V)) solution was added to perform a washing step. In the washing step, as described above, the mixture was stirred for 1 minute after the addition of acetonitrile, and then magnetic separation was performed to remove the acetonitrile, which was repeated twice. After the washing step, a small amount of the solution after washing was saved for TLC.

[0051] The reagents used in peptide synthesis, such as amino acids and condensing agents, are all relatively highly polar compounds. To efficiently wash away excess reagents after the reaction is complete, it is preferable to use a highly polar solvent such as acetonitrile. This suggests that applying the separation operation of the separation system 1 to liquid-phase peptide synthesis using hydrophobic TAGs can effectively separate peptides (amino acids) bound to hydrophobic carriers from excess reagents.

[0052] In the above example, hydrophobic TAG was dissolved in cyclohexane, a nonpolar solvent, in which magnetic nanoparticles (concentration: 5.0 mg / mL) coated with saturated alkylphosphonic acid having 14 carbon atoms were dispersed, and impurities were separated and removed with acetonitrile. Synthesis of five residues was achieved. In other words, it was confirmed that the elongation reaction proceeded when leucine-enkephalin was used as a model peptide.

[0053] 1: Separation system, 2: Separation tank, 2A: Discharge port, 3A: Magnetism imparting unit, 3B: Magnetism imparting unit, 4A: Separation unit, 4B: Separation unit, 5A: First solvent tank, 5B: Second solvent tank, 6: Heater, 7A: First receiving tank, 7B: Second receiving tank, 8: Stirring device, 8A: Motor, 8B: Stirring member, 9A: Automatic valve, 9B: Automatic valve, 9C: Automatic valve, 10: Control unit, 90: Pipe line

Claims

1. A liquid separation system comprising a storage unit, a magnetism imparting unit, and a separation unit, wherein the storage unit is configured to store a first solvent which is a non-polar solvent and a second solvent which is a polar solvent, the magnetism imparting unit is configured to impart magnetism to one of the first solvent or the second solvent to turn it into a magnetic fluid by supplying magnetic nanoparticles which are dispersible in either the first solvent or the second solvent, the separation unit is configured to separate the first solvent and the second solvent in the storage unit by magnetic force, and the magnetic nanoparticles are modified with a surface modifier consisting of a compound having a phosphonic acid group, an isocyanate group, a carboxy group, an alcohol group, a thiol group, or an amino group.

2. A liquid separation system according to claim 1, wherein the magnetic imparting unit is configured to make the first solvent magnetically fluid.

3. A liquid separation system according to claim 1 or 2, wherein the first solvent is cyclohexane, hexane, heptane, MTBE (methyl tert-butyl ether), N,N-dimethylformamide, tetrahydrofuran, toluene, dichloromethane, chloroform, cyclopentyl methyl ether, ethyl acetate, or N-methylpyrrolidone, and the second solvent is acetonitrile, DMF (N,N-dimethylformamide), DMSO (dimethyl sulfoxide), methanol, ethanol, propanol, acetone, or water.

4. The liquid separation system according to claim 1, wherein the surface modifier is an alkylphosphonic acid or an alkenylphosphonic acid.

5. A liquid separation system according to claim 4, wherein the alkylphosphonic acid or the alkenylphosphonic acid has 10 or more carbon atoms.

6. A liquid separation system according to claim 4, wherein the alkylphosphonic acid or the alkenylphosphonic acid has 14 or more carbon atoms.

7. A liquid separation system according to claim 3, wherein the solute of the first solvent is a target substance of a chemical reaction, and the solute of the second solvent is an impurity produced during the chemical reaction.

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