Method for producing organic fine particles

Abstract

To provide a method for producing organic fine particles having a relatively uniform particle size.SOLUTION: The method for producing organic fine particles includes a mixing step and a precipitation step. In the mixing step, the organic compound solution and the second liquid are mixed at a mixing temperature to obtain a raw material liquid in which droplets of the organic compound solution are dispersed in the second liquid. In the precipitation step, the raw material solution is brought to a precipitation temperature to precipitate fine particles of the organic compound contained in the organic compound solution. The organic compound solution contains a first solvent and an organic compound dissolved in the first solvent. The second liquid phase-separates from the first solvent at a critical temperature or higher and is compatible with the first solvent at a temperature lower than the critical temperature. The organic compound is sparingly soluble in the second liquid. The mixing temperature is above the critical temperature and the deposition temperature is below the critical temperature.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present application relates to a method for producing organic fine particles having a relatively uniform particle size, and to an organic fine particle-containing material having the organic fine particles. [Background technology]

[0002] A method described in Patent Document 1 is known as a method for producing polyamic acid microparticles, which are organic microparticles. In this method, a polyamic acid solution and a poor solvent for polyamic acid are mixed in a micromixer to prepare an emulsion, and then the emulsion is immediately heated in a microchannel to precipitate the polyamic acid as microparticles in the poor solvent. In this method, the polyamic acid solution and the poor solvent for polyamic acid are rapidly mixed to form droplets of the polyamic acid solution in the poor solvent, making it difficult to achieve a uniform particle size for the polyamic acid microparticles. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5120898 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present application is to provide a method for producing organic fine particles having a relatively uniform particle size, and an organic fine particle-containing material containing such organic fine particles. [Means for solving the problem]

[0005] The method for producing organic fine particles of the present application includes a mixing step of mixing an organic compound solution with a second liquid at a mixing temperature to obtain a raw material liquid in which droplets of the organic compound solution are dispersed in the second liquid, and a precipitation step of heating the raw material liquid to a precipitation temperature to precipitate fine particles of the organic compound contained in the organic compound solution, wherein the organic compound solution contains a first solvent and an organic compound dissolved in the first solvent, the second liquid phase-separates from the first solvent at a critical temperature or higher and is compatible with the first solvent below the critical temperature, the organic compound is poorly soluble in the second liquid, the mixing temperature is above the critical temperature, and the precipitation temperature is below the critical temperature.

[0006] The organic microparticle-containing material of the present application contains a third liquid and a fourth liquid, a mixed liquid in which the third liquid and the fourth liquid are miscible with each other, and microparticles of multiple organic compounds present in the mixed liquid, wherein the fourth liquid phase-separates from the third liquid at a temperature above its critical temperature and is miscible with the third liquid below its critical temperature, and the CV value of the particle size of the microparticles of the multiple organic compounds is 10% or less. [Effects of the Invention]

[0007] In the method for producing organic fine particles of the present application, the solvent in the organic compound solution is slowly extracted into the surrounding liquid, causing the organic compound fine particles to precipitate. Furthermore, the organic fine particle-containing material of the present application contains organic compound fine particles with a particle size CV value of 10% or less. Therefore, the method for producing organic fine particles and the organic fine particle-containing material of the present application can produce organic fine particles with a relatively uniform particle size. [Brief explanation of the drawings]

[0008] [Figure 1] A graph showing the relationship between the vol% of C6E2 in a mixture of water and C6E2 and the critical temperature. [Figure 2] 1 is a cross-sectional schematic view of a microchannel device that can be used in a method for producing organic fine particles according to an embodiment. [Figure 3] 1 is an SEM image of fine particles of the organic compound of Example 1. [Figure 4] 1 is an SEM image of fine particles of the organic compound of Example 2. [Figure 5] 10 is an SEM image of fine particles of the organic compound of Example 3. [Figure 6] 10 is an SEM image of fine particles of the organic compound of Example 4. [Figure 7] 10 is an SEM image of fine particles of the organic compound of Example 5. [Figure 8] 10 is an SEM image of fine particles of the organic compound of Example 6. [Figure 9] 10 is an SEM image of fine particles of the organic compound of Example 7. [Figure 10] 10 is an SEM image of fine particles of the organic compound of Example 8. DETAILED DESCRIPTION OF THE INVENTION

[0009] The method for producing organic fine particles and the organic fine particle-containing material of the present application will be described based on embodiments and examples. Repetitive explanations will be omitted where appropriate. When a range between two numerical values ​​is expressed using "to" in the present application, these two numerical values ​​are also included in the range. The method for producing organic fine particles of the present application includes a mixing step and a precipitation step. In the mixing step, an organic compound solution and a second liquid are mixed at a mixing temperature to obtain a raw material liquid in which droplets of the organic compound solution are dispersed in the second liquid. That is, the raw material liquid is in a two-phase liquid-liquid state of droplets of the organic compound solution and the second liquid. The droplets dispersed in the raw material liquid have a high uniformity in droplet size, and the droplet size is so uniform that they do not coalesce, which also improves the uniformity of the particle size of the organic compound fine particles obtained in the subsequent precipitation step.

[0010] To prevent droplets in the raw material liquid from coalescing, the ratio of the volume of the organic compound solution to the volume of the second liquid when mixing the organic compound solution with the second liquid (volume of organic compound solution / volume of second liquid) is preferably 1 / 100 to 1 / 10, more preferably 1 / 100 to 1 / 20, and even more preferably 1 / 100 to 1 / 50. When the organic compound solution and the second liquid are continuously supplied during the mixing process, this volume ratio corresponds to the ratio of the supply flow rates of the organic compound solution and the second liquid. The organic compound solution contains a first solvent and an organic compound dissolved in the first solvent. In the present application, the organic compound also includes a salt of the organic compound. Examples of organic compounds include high-molecular-weight organic compounds such as polyvinyl alcohol and sodium alginate, as well as medium- to low-molecular-weight organic compounds such as ubiquinone and cholesterol.

[0011] The second liquid undergoes phase separation from the first solvent at or above the critical temperature and is miscible with the first solvent below the critical temperature. In other words, the critical temperature is the boundary temperature at which a liquid mixture of the first solvent and the second liquid enters a two-phase liquid-liquid state or a single-phase liquid state. A liquid mixture of the first solvent and the second liquid enters a two-phase liquid-liquid state above the critical temperature and a single-phase liquid state below the critical temperature. As long as such a critical temperature exists, the second liquid and the first solvent may be pure substances or mixtures. Examples of such combinations of the second liquid and the first solvent, when they are pure substances, include amine and water, ether and water, and glycol ether and water.

[0012] Amines include triethylamine and 2,6-lutidine. Ethers include diethylene glycol diethyl ether and diethylene glycol monoethyl ether acetate. Linear glycol ethers are represented by the following general formula and are sometimes abbreviated as CnEm: (C n H 2n+1 O)-(CH2CH2O) m -H Linear glycol ethers include C4E1, C5E2, C6E2, C6E3, C7E3, C8E3, C6E4, C7E4, C8E4, and C8E5.Other glycol ethers include ethylene glycol monoisobutyl ether, propylene glycol propyl ether, diethylene glycol 2-methyl-1-butyl ether, and dipropylene glycol monopropyl ether.

[0013] Furthermore, when one of the second liquid and the first solvent is a mixture, two of water, alcohol, and glycol ether may be one of the second liquid and the first solvent, for example, the second liquid, and the remaining one of water, alcohol, and glycol ether may be the other of the second liquid and the first solvent, for example, the first solvent. Thus, even in a ternary liquid mixture, a critical temperature appears, and there exists a composition that becomes a two-phase liquid-liquid state above the critical temperature and becomes a single-phase liquid state below the critical temperature.

[0014] Figure 1 shows the critical temperature when the first solvent is water and the second liquid is C6E2. As shown in Figure 1, the critical temperature changes depending on the mixing ratio of water and C6E2. Figure 1 also shows the relationship between the vol% of C6E2 in a water and C6E2 mixture and the critical temperature. In this way, by mixing multiple liquids while changing their composition and observing phase separation and miscibility as the temperature is increased or decreased, the critical temperature of the liquid mixture can be confirmed. Organic compounds are poorly soluble in the second liquid. "Poorly soluble" means that only 1g or less of the solute dissolves in 100g of solvent. The mixing temperature is above the critical temperature.

[0015] In the mixing step, the organic compound solution and the second liquid are mixed at a mixing temperature equal to or higher than the critical temperature, so that the first solvent and the second liquid, i.e., the organic compound solution and the second liquid, undergo phase separation, and droplets of the organic compound solution are dispersed in the second liquid. The organic compound may be polyvinyl alcohol, the first solvent may be water, and the second liquid may contain a glycol ether. Examples of such second liquids include mixtures of water and glycol ether. Alternatively, the organic compound may be sodium alginate, the first solvent may be water, and the second liquid may contain a glycol ether and an alcohol. Examples of such second liquids include mixtures of water, glycol ether, and an alcohol.

[0016] In the precipitation process, the raw material liquid is heated to a precipitation temperature to precipitate fine particles of the organic compound contained in the organic compound solution. The precipitation temperature is below the critical temperature. By lowering the temperature of the raw material liquid, which is in a two-phase liquid-liquid state in which droplets of the organic compound solution are dispersed in the second liquid, to a precipitation temperature below the critical temperature, the first solvent in the droplets of the organic compound solution is extracted into the second liquid, and the organic compound solution changes to a single-phase liquid state of the first solvent and the second liquid. As the temperature of the raw material liquid decreases, the droplets of the organic compound solution gradually concentrate and precipitate as fine particles of the organic compound in the single-phase liquid mixture of the first solvent and the second liquid. The critical temperature is preferably 40°C or higher. This is because the raw material liquid can be cooled to a temperature below the critical temperature, eliminating the need for a cooling means for the raw material liquid, and fine particles of the organic compound are precipitated.

[0017] In the mixing step, the organic compound solution and the second liquid may be continuously supplied and mixed, and the mixing step and the precipitation step may be continuously performed in a continuous flow path. By continuously supplying the organic compound solution and the second liquid and continuously performing the mixing step and the precipitation step in a continuous flow path, organic compound microparticles can be efficiently obtained. In this case, if the organic compound solution and the second liquid, both at temperatures above the critical temperature, are separately supplied into the flow path to produce a raw material liquid at temperatures above the critical temperature that is mixed in the flow path, the raw material liquid cools as it moves downstream in the flow path, and organic compound microparticles precipitate in the downstream portion of the flow path. In this case, one or more of the mixing portion of the organic compound solution and the second liquid and the upstream portion of the flow path may be heated. This is because a two-phase raw material liquid in which the organic compound solution droplets are small and highly dispersed is obtained in the upstream portion of the flow path.

[0018] FIG. 2 shows a schematic cross section of a microchannel device 10 having channels through which the mixing step and the precipitation step can be performed continuously. The microchannel device 10 includes a dispersed phase introduction channel 12 for introducing an organic compound solution S, two continuous phase introduction channels 14a and 14b for introducing a second liquid L, a mixing section 16 where the organic compound solution S and the second liquid L join and mix, and a microchannel 18 through which the raw material liquid flows. The microchannel 18 includes an upstream section 18a and a downstream section 18b. The inner diameter of the dispersed phase introduction channel 12 is, for example, 100 μm to 200 μm. The inner diameter of the continuous phase introduction channels 14a and 14b is, for example, 200 μm to 400 μm. The inner diameter of the microchannel 18 is, for example, 1000 μm to 2000 μm.

[0019] The upstream section 18a is maintained at a temperature equal to or higher than the critical temperature, and contains a raw material liquid containing droplets D of an organic compound solution. A heating means may be provided around the upstream section 18a. The downstream section 18b is maintained at a temperature lower than the critical temperature, and contains organic compound particles P. A cooling means may be provided around the downstream section 18b. If necessary, a separate pipe may be connected to the outlet of the microchannel 18, and the organic compound particles may be precipitated in this pipe. The arrows in the dispersed phase introduction channel 12, the continuous phase introduction channels 14a and 14b, and the microchannel 18 indicate the flow directions of the organic compound solution S, the second liquid L, the organic compound solution droplets D, and the organic compound particles P.

[0020] The organic compound solution S introduced from the dispersed phase introduction channel 12 and the second liquid L introduced from the two continuous phase introduction channels 14a and 14b join and mix in the mixing section 16. This liquid mixture then moves to the microchannel 18, and droplets D of the organic compound solution are formed in the upstream section 18a. Because the first solvent in the organic compound solution S and the second liquid L undergo phase separation, the droplets D of the organic compound solution do not disappear. Furthermore, because the organic compound is poorly soluble in the second liquid L, the organic compound in the droplets D of the organic compound solution is hardly extracted into the second liquid L.

[0021] A second liquid L is present around the droplets D of the organic compound solution. The droplets D of the organic compound solution and the second liquid L constitute the raw material liquid. When the raw material liquid moves to the downstream section 18b and drops below its critical temperature, the first solvent in the droplets D of the organic compound solution and the second liquid L become miscible, and the first solvent is extracted into the second liquid L. The droplets D of the organic compound solution become concentrated and smaller, eventually precipitating as fine particles P of the organic compound. A liquid mixture of the first solvent and the second liquid L is present around the fine particles P of the organic compound. That is, in the downstream section 18b, a mixed liquid in which multiple liquids are miscible, and fine particles P of multiple organic compounds in this mixed liquid, exist. As will be described later in the Examples, the particle size uniformity of the fine particles P of the multiple organic compounds is high. Furthermore, because the organic compound is poorly soluble in the second liquid L, the fine particles P of the organic compound are barely soluble in the second liquid L.

[0022] The organic microparticle-containing material of the present embodiment includes a liquid mixture containing a third liquid and a fourth liquid, in which the third liquid and the fourth liquid are miscible, and microparticles of multiple organic compounds present in the liquid mixture. The coefficient of variation (CV) of the particle diameters of the multiple organic compound microparticles is 10% or less. The CV of the particle diameters of the organic compound microparticles is calculated using the formula "standard deviation of particle diameters of the organic compound microparticles / average particle diameter of the organic compound microparticles." The CV of the droplet diameter is calculated in the same manner.

[0023] The particle size of the microparticles was determined by measuring the maximum width of the microparticles that appeared in the SEM image. The average particle size of the microparticles was the number average value of the particle sizes of 20 to 750 randomly selected microparticles that appeared in the SEM image. The standard deviation of the particle size of the microparticles was also calculated based on the particle sizes of these 20 to 750 particles. In this application, a CV value of 10% or less is referred to as monodisperse. Using the microchannel device 10, it is also possible to produce monodisperse organic compound microparticles with a CV value of 2.8%.

[0024] The fourth liquid undergoes phase separation from the third liquid at or above its critical temperature and is compatible with the third liquid below its critical temperature. Examples of combinations of the third and fourth liquids include the same combinations of the first solvent and the second liquid described in the embodiment of the method for producing organic microparticles. The organic compound may be polyvinyl alcohol, the third liquid may be water, and the fourth liquid may be a glycol ether. Alternatively, the organic compound may be sodium alginate, the third liquid may be water, and the fourth liquid may be a mixture of glycol ether and alcohol. [Example]

[0025] Microparticles of organic compounds were prepared using a microfluidic device as shown in Figure 1. The dispersed phase introduction channel, continuous phase introduction channel, and microchannel were made of polydimethylsiloxane (SILPOT 184, Dow-Toray Co., Ltd.). Heating devices were installed around the mixing section of the microfluidic device and the upstream section of the microchannel. A PFA tube (Isis Co., Ltd., JPTA163205) connected to the outlet of the microchannel was cooled to room temperature, and microparticles of the organic compound were precipitated inside the tube. A cooling device was also installed around the tube.

[0026] Example 1 A dispersed phase was prepared as an aqueous solution of polyvinyl alcohol (Wako, degree of polymerization n = 1500-1800, 98% hydrolyzed) at a concentration of 30 mg / mL in distilled water. A continuous phase, a second liquid, was prepared by mixing distilled water and diethylene glycol monohexyl ether (C6E2) (TCI, D0501, hereinafter) at a volume ratio of distilled water to C6E2 = 19:80. Polyvinyl alcohol is poorly soluble in this continuous phase and C6E2. Furthermore, above 70°C, the dispersed and continuous phases were immiscible and completely separated into two phases.

[0027] Using a syringe pump (Harvard, BS4 70-2208) (hereinafter the same), the dispersed phase was delivered from the dispersed phase inlet channel to the microchannel heated to 70°C at a rate of 0.002 mL / min. Also, using a syringe pump (YMC, YSP-202) (hereinafter the same), the continuous phase was delivered from one continuous phase inlet channel to the microchannel heated to 70°C at a rate of 0.099 mL / min. In other words, a total of 0.198 mL / min of continuous phase was delivered to the microchannel from the two continuous phase inlet channels.

[0028] In the microchannel, monodisperse dispersed phase droplets with an average diameter of 167.8 μm and a CV value of 6.1% were generated in the continuous phase. The droplet diameter was determined by measuring the maximum width of droplets appearing in a video recorded with a high-speed microscope (Keyence VW-9000; the same applies hereinafter). The average droplet diameter was the number-average value of the diameters of 50 droplets selected from the video recorded with the high-speed microscope. The standard deviation of the droplet diameters was also calculated based on the diameters of these 50 droplets. The raw liquid, a mixture of the dispersed phase droplets and the continuous phase in the microchannel, passed through the outlet of the microchannel and cooled to room temperature in the tube. Polyvinyl alcohol microparticles precipitated in the tube. Figure 3 shows an electron microscope image of the resulting polyvinyl alcohol microparticles. Monodisperse polyvinyl alcohol microparticles with an average diameter of 35.9 μm and a CV value of 9.5% were confirmed.

[0029] Example 2 Polyvinyl alcohol microparticles were prepared in the same manner as in Example 1, except that the dispersed phase was delivered at a rate of 0.004 mL per minute and the microchannel was heated to 80°C. Monodispersed dispersed phase droplets with an average droplet diameter of 330.2 μm and a CV value of 1.4% were generated in the continuous phase. An electron microscope image of the obtained polyvinyl alcohol microparticles is shown in Figure 4. Monodispersed polyvinyl alcohol microparticles with an average particle diameter of 105.0 μm and a CV value of 8.8% were confirmed.

[0030] Example 3 Polyvinyl alcohol microparticles were prepared in the same manner as in Example 2, except that the dispersed phase was delivered at 0.003 mL / min and the continuous phase was delivered to one continuous phase inlet channel at 0.1485 mL / min (total of 0.297 mL / min to the two continuous phase inlet channels). Monodispersed dispersed phase droplets with an average droplet diameter of 258.6 μm and a CV value of 1.0% were produced in the continuous phase. An electron microscope image of the resulting polyvinyl alcohol microparticles is shown in Figure 5. Monodispersed polyvinyl alcohol microparticles with an average particle diameter of 85.6 μm and a CV value of 9.9% were confirmed.

[0031] Example 4 Polyvinyl alcohol microparticles were prepared in the same manner as in Example 1, except that the polyvinyl alcohol concentration of the dispersed phase was 30 mg / mL, the continuous phase was composed of distilled water and C6E2 at a volume ratio of 1:5, the dispersed phase was delivered at 0.008 mL / min, and the continuous phase was delivered at 0.096 mL / min to one continuous phase inlet (total of 0.192 mL / min to the two continuous phase inlet channels). Monodisperse dispersed phase droplets with an average droplet diameter of 435.4 μm and a CV value of 3.1% were generated in the continuous phase. An electron microscope image of the resulting polyvinyl alcohol microparticles is shown in Figure 6. Monodisperse polyvinyl alcohol microparticles with an average particle diameter of 78.2 μm and a CV value of 7.8% were confirmed.

[0032] Example 5 Polyvinyl alcohol microparticles were prepared in the same manner as in Example 4, except that the polyvinyl alcohol concentration in the dispersed phase was 15 mg / mL, the continuous phase had a volume ratio of distilled water: 2-butoxyethanol (Wako, 059-03716 (hereinafter the same)): 1-hexanol (Wako, 081-00516 (hereinafter the same)) = 11:60:25, and the microchannel was heated to 75°C. Polyvinyl alcohol is poorly soluble in the continuous phase, 2-butoxyethanol, and 1-hexanol. Monodisperse dispersed phase droplets with an average droplet diameter of 307.5 μm and a CV value of 1.5% were generated in the continuous phase. An electron microscope image of the obtained polyvinyl alcohol microparticles is shown in Figure 7. Monodisperse polyvinyl alcohol microparticles with an average particle diameter of 79.6 μm and a CV value of 6.9% were confirmed.

[0033] Example 6 Polyvinyl alcohol microparticles were prepared as in Example 5, except that the continuous phase was composed of a volume ratio of distilled water, 2-butoxyethanol, and 1-hexanol of 13:60:25, the dispersed phase was delivered at 0.006 mL / min, and the continuous phase was delivered at 0.144 mL / min to one continuous phase inlet (a total of 0.288 mL / min to both continuous phase inlet channels). Monodisperse dispersed phase droplets with an average droplet diameter of 394.9 μm and a CV value of 1.4% were generated in the continuous phase. An electron microscope image of the resulting polyvinyl alcohol microparticles is shown in Figure 8. Monodisperse polyvinyl alcohol microparticles with an average particle diameter of 88.8 μm and a CV value of 2.8% were confirmed.

[0034] Example 7 Polyvinyl alcohol microparticles were prepared in the same manner as in Example 5, except that the polyvinyl alcohol concentration in the dispersed phase was 7.5 mg / mL, the dispersed phase was delivered at a rate of 0.012 mL / min, and the microchannel was heated to 70°C. Monodisperse dispersed phase droplets with an average droplet diameter of 426.8 μm and a CV value of 1.4% were generated in the continuous phase. An electron microscope image of the obtained polyvinyl alcohol microparticles is shown in Figure 9. Monodisperse polyvinyl alcohol microparticles with an average particle diameter of 63.2 μm and a CV value of 8.2% were confirmed.

[0035] Example 8 The dispersed phase was prepared as an aqueous solution of sodium alginate (TCI, A0205) dissolved in distilled water at a concentration of 10 mg / mL. The continuous phase, a second liquid, was prepared by mixing distilled water, C4E1, and 1-hexanol in a volume ratio of distilled water:C4E1:1-hexanol = 13:60:25. Note that sodium alginate is poorly soluble in this continuous phase, C4E1, and 1-hexanol. Furthermore, above 70 °C, the dispersed and continuous phases were immiscible and completely separated into two phases.

[0036] The dispersed phase was delivered from the dispersed-phase inlet channel to a microchannel heated to 70°C at a rate of 0.002 mL / min. The continuous phase was delivered from one continuous-phase inlet channel to a microchannel heated to 70°C at a rate of 0.22 mL / min. A total of 0.44 mL / min of continuous phase was delivered to the microchannel from the two continuous-phase inlet channels. Monodisperse dispersed-phase droplets with an average droplet diameter of 217.0 μm and a CV value of 6.0% were generated in the continuous phase in the microchannel. The raw material solution in the microchannel passed through the outlet of the microchannel and was cooled to 10°C in a tube. Sodium alginate microparticles precipitated in the tube. Figure 10 shows an electron microscope image of the resulting sodium alginate microparticles. Monodisperse sodium alginate microparticles with an average diameter of 38.4 μm and a CV value of 7.6% were confirmed. [Explanation of symbols]

[0037] 10 Microfluidic Device 12 dispersed phase introduction channel, 14a Continuous phase introduction channel 14b Continuous phase introduction channel 16 Mixing section 18 Microchannel 18a upstream part 18b downstream S organic compound solution L Second liquid D. A droplet of organic compound solution P: Fine particles of organic compounds

Claims

1. a mixing step of mixing the organic compound solution and the second liquid at a mixing temperature to obtain a raw material liquid in which droplets of the organic compound solution are dispersed in the second liquid; a precipitation step of heating the raw material solution to a precipitation temperature to precipitate fine particles of the organic compound contained in the organic compound solution; A method for producing organic fine particles comprising: the organic compound solution contains a first solvent and the organic compound dissolved in the first solvent; the second liquid undergoes phase separation from the first solvent at a critical temperature or higher and is compatible with the first solvent at a temperature lower than the critical temperature; the organic compound is poorly soluble in the second liquid, A method for producing organic fine particles, wherein the mixing temperature is equal to or higher than the critical temperature, and the deposition temperature is lower than the critical temperature.

2. In claim 1, In the mixing step, the organic compound solution and the second liquid are mixed while being continuously supplied, The method for producing organic fine particles comprises continuously carrying out the mixing step and the deposition step in a continuous flow path.

3. In claim 1 or 2, A method for producing organic fine particles, wherein the organic compound is polyvinyl alcohol, the first solvent is water, and the second liquid contains glycol ether.

4. In claim 1 or 2, A method for producing organic microparticles, wherein the organic compound is sodium alginate, the first solvent is water, and the liquid contains a glycol ether.

5. In claim 1 or 2, The method for producing organic fine particles, wherein the critical temperature is 40° C. or higher.

6. a mixed liquid containing a third liquid and a fourth liquid, wherein the third liquid and the fourth liquid are miscible with each other; fine particles of a plurality of organic compounds present in the mixed liquid; An organic fine particle-containing material having the fourth liquid undergoes phase separation from the third liquid at a critical temperature or higher and is compatible with the third liquid below the critical temperature; The organic fine particle-containing material has a CV value of particle diameters of the fine particles of the plurality of organic compounds of 10% or less.

7. In claim 6, The organic fine particle-containing material, wherein the organic compound is polyvinyl alcohol, the third liquid is water, and the fourth liquid is glycol ether.

8. In claim 6, The organic fine particle-containing material, wherein the organic compound is sodium alginate, the third liquid is water, and the fourth liquid is a mixture of glycol ether and alcohol.

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