Liquid feeding device for particle dispersion

Abstract

To provide a liquid feeding device that feeds a particle dispersion containing particulate raw material to a micro flow passage for micro flow synthesis without blocking in a reaction that uses a raw material not soluble in a solvent, such as coupling reaction.SOLUTION: A liquid feeding device for particle dispersion is for particle dispersion with particles having a particle size distribution being dispersed in liquid, and includes: a dispersion tank with particle dispersion; a liquid feeding pump to feed the particle dispersion; and a piping connected to the liquid feeding pump and sucking the particle dispersion from the dispersion tank. For the piping, a piping diameter D1 on the side of the liquid feeding pump is smaller than a piping diameter D2 on the side of the dispersion tank, and the relationship of D1<D2 is satisfied.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a liquid feeding device that feeds a particle dispersion liquid containing raw material particles to a microchannel for microflow synthesis.

Background Art

[0002] In recent years, a method using a flow-through microreactor in chemical synthesis has attracted attention. Generally, a microreactor is a device that performs a reaction in a fine channel with an internal structure having an inner diameter of about several μm to several mm. Such a microreactor has characteristics such as high temperature controllability and good mixing efficiency because of its large surface area per unit volume in chemical synthesis. In chemical synthesis, since the surface area is large and the heat transfer property is high, for example, heat generated during the reaction is also easily diffused to the surroundings, temperature control becomes possible, and effects such as an increase in yield and a reduction in the molecular weight dispersity of the polymer material can be obtained. In addition, it is used for reactions using unstable raw materials because of the high mixing efficiency speed (for example, see Patent Document 1).

[0003] On the other hand, in reactions using various metal catalysts such as coupling reactions, a metal catalyst with low solubility in a solvent may be used. Even in such reactions, synthesis can be performed without problems when synthesis is carried out in a normal flask or the like. However, in the method using a flow-through microreactor, since a thin microchannel is used for liquid feeding, if the metal catalyst contains coarse particles, it is likely to be blocked, and there is a problem that stable liquid feeding is difficult.

[0004] On the contrary, a method of stably feeding liquid has been proposed by devising the installation direction of a dispersion liquid containing fine particles from the introduction part to the discharge part of a microchannel (for example, see Patent Document 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] However, in the above method (Patent Document 2), when slightly coarse particles are mixed in the particles of the raw material, there is a problem that it immediately clogs.

[0007] The present disclosure aims to solve the above conventional problems. That is, the present disclosure provides a liquid feeding device that feeds a particle dispersion liquid containing particulate raw materials into a microchannel for microflow synthesis in a reaction using raw materials that do not dissolve in a solvent such as a coupling reaction, without clogging.

MEANS FOR SOLVING THE PROBLEMS

[0008] To achieve the above object, a liquid feeding device for a particle dispersion liquid according to the present disclosure is a liquid feeding device that feeds a particle dispersion liquid in which particles having a particle size distribution are dispersed in a liquid, and includes a dispersion liquid tank having the particle dispersion liquid, a liquid feeding pump that feeds the particle dispersion liquid, and a pipe that is connected to the liquid feeding pump and sucks the particle dispersion liquid from the dispersion liquid tank. The pipe has a tapered portion in which the pipe diameter narrows from the dispersion liquid tank side to the liquid feeding pump side, and the pipe diameter D1 on the liquid feeding pump side in the tapered portion is smaller than the pipe diameter D2 on the dispersion liquid tank side, satisfying the relationship D1 < D2.

EFFECTS OF THE INVENTION

[0009] As described above, according to the liquid feeding device for a particle dispersion liquid according to the present disclosure, even when coarse particles are mixed in the particle dispersion liquid of the raw material, it is possible to feed the particle dispersion liquid of the raw material without causing clogging and in a stable flow state.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0011] The liquid feeding device for a particle dispersion liquid according to the first aspect is a liquid feeding device for a particle dispersion liquid in which particles having a particle size distribution are dispersed in a liquid, and includes a dispersion liquid tank having the particle dispersion liquid, a liquid feeding pump for feeding the particle dispersion liquid, and a pipe connected to the liquid feeding pump and sucking the particle dispersion liquid from the dispersion liquid tank. The pipe has a tapered part in which the pipe diameter narrows from the dispersion liquid tank side to the liquid feeding pump side, and the pipe diameter D1 on the liquid feeding pump side in the tapered part is smaller than the pipe diameter D2 on the dispersion liquid tank side, satisfying the relationship D1 < D2.

[0012] The liquid feeding device for a particle dispersion liquid according to the second aspect may be arranged in the direction intersecting with the liquid level of the dispersion liquid tank in the first aspect.

[0013] The liquid feeding device for a particle dispersion liquid according to the third aspect, in the first or second aspect, takes particles with a particle diameter of d1 or more in the particle size distribution as coarse particles, and the particle density of the coarse particles is ρ s , the solvent density of the particle dispersion liquid is ρ l , the viscosity is μ, and the flow rate of the liquid feeding pump is Q. Then, for the following formula (1) 2.0×d1^2×(ρ s -ρ l )>μ×Q / D2^2 (1) , the flow of coarse particles with a particle diameter of d1 or more into the tapered part of the pipe may be suppressed.

[0014] The liquid feeding device for a particle dispersion liquid according to the fourth aspect may further include an evaluation unit for measuring the particle concentration of the particle dispersion liquid fed from the liquid feeding pump, and a control unit for controlling the flow rate of the liquid feeding pump based on the particle concentration in the particle dispersion liquid measured by the evaluation unit in any of the first to third aspects.

[0015] In the liquid feeding device for the particle dispersion according to the fifth aspect, in any of the first to fourth aspects described above, the particle diameter of the coarse particles may be larger than 50 μm.

[0016] In the liquid feeding device for the particle dispersion according to the sixth aspect, in any of the first to fifth aspects described above, the pipe diameter D2 on the dispersion tank side may be 1.0 mm or more and 9.5 mm or less.

[0017] In the liquid feeding device for the particle dispersion according to the seventh aspect, in any of the first to sixth aspects described above, a circulation pipe may be provided to return a part of the particle dispersion sucked from the pipe to the liquid feeding pump to the dispersion tank.

[0018] In the liquid feeding device for the particle dispersion according to the eighth aspect, in any of the first to seventh aspects described above, the particles are particles of a raw material for microflow synthesis, and the particle dispersion may be fed from the liquid feeding pump to the microchannel for microflow synthesis.

[0019] Hereinafter, the liquid feeding device for the particle dispersion according to the embodiment will be described with reference to the accompanying drawings. In the drawings, the same reference numerals are given to substantially the same members.

[0020] (Embodiment 1) <Liquid Feeding Device for Particle Dispersion> FIG. 1 is a schematic diagram showing the configuration from the liquid feeding device 10 for the particle dispersion according to Embodiment 1 to the microchannel 20 for microflow synthesis. FIG. 2 is an enlarged cross-sectional view showing the configuration of the coarse particle suppression unit 100 including the tapered portion 30 of the pipe in the liquid feeding device for the particle dispersion according to Embodiment 1. In the drawings, for convenience, the vertically upward direction is the Z direction, the right hand direction in the horizontal plane is the X direction, and the direction from the front to the back of the paper surface is the Y direction. As shown in Fig. 1, the liquid feeding device 10 for a particle dispersion liquid according to Embodiment 1 includes a dispersion liquid tank 103 containing the particle dispersion liquid, a liquid feeding pump (circulation pump 120, dispersion liquid feeding pump 121) for feeding the particle dispersion liquid, and a second pipe 101 connected to the liquid feeding pumps 120 and 121 and sucking the particle dispersion liquid from the dispersion liquid tank 103. The second pipe 101 has a tapered portion 30 whose pipe diameter becomes narrower from the side of the dispersion liquid tank 103 toward the side of the liquid feeding pumps 120 and 121. In the tapered portion 30, the pipe diameter D1 on the side of the liquid feeding pumps 120 and 121 is smaller than the pipe diameter D2 on the side of the dispersion liquid tank 103, satisfying the relationship D1 < D2. According to this liquid feeding device for a particle dispersion liquid, even when coarse particles are mixed in the raw material particle dispersion liquid, the tapered portion 30 enables the raw material particle dispersion liquid to be fed without causing blockage and in a stable flow state.

[0021] Also, in Fig. 1, a circulation pump 120 and a dispersion liquid feeding pump 121 are provided as the liquid feeding pumps, but it is not limited thereto, and a configuration that does not circulate the particle dispersion liquid may be adopted. In this case, the circulation pump may not be provided.

[0022] Furthermore, the liquid feeding device 10 for a particle dispersion liquid may include, for example, a particle concentration evaluation unit 200 and a control device 300. With this liquid feeding device 10 for a particle dispersion liquid, the particle dispersion liquid may be fed into the microchannel 20. Further, it may be fed to a mixer 130 which is a microchannel for microflow synthesis, and for example, mixed with one raw material solution fed from a second raw material tank 110 via a second raw material liquid feeding pump 122 in the mixer 130, then fed to a reactor 131, and microflow synthesis may be performed while controlling the temperature with a temperature regulator as needed.

[0023] Here, in microflow synthesis, one raw material solution is taken as the particle dispersion liquid and the other raw material solution is taken as the dissolved solution, and it will be described in detail, but these cases are not particularly limited.

[0024] Hereinafter, each member constituting the liquid feeding device 10 for a particle dispersion liquid will be described.

[0025] <Dispersion tank> The dispersion tank 103 contains a particle dispersion. The dispersion tank 103 only needs to be able to hold the particle dispersion and can be composed of commonly used materials.

[0026] <Particle dispersion> The particle dispersion may be any particle dispersion in which particles having a particle size distribution are dispersed in a liquid. Also, the material of the particles is not particularly limited, but a material miscible with the solvent to be used is preferred. If it is not miscible with the solvent, the particles will aggregate, making it difficult to produce a particle dispersion in which the particles are dispersed. For example, metal catalysts using Ni, Pd, Pt, etc. as catalysts for chemical synthesis, ceramic particles such as silica and alumina as base particles, and polymer particles such as polymethyl methacrylate and polystyrene can be mentioned.

[0027] The particle diameter d1 of the coarse particles of the particles is preferably larger than 50 μm. More preferably, it is larger than 70 μm, and even more preferably, it is larger than 100 μm. When the particle diameter of the coarse particles mixed in the raw material particles is smaller than 50 μm, the gravity acting on the particles is small, and in order to suppress it, it is necessary to slow down the flow rate, which takes time for the circulation of the dispersion liquid and makes the particles likely to settle.

[0028] <Solvent> The solvent is not particularly limited, but a solvent that is miscible with the raw material particles and has a boiling point equal to or higher than the reaction temperature in microflow synthesis is selected. For example, aqueous solutions, alcohol-based such as methanol and ethanol, ether-based such as diethyl ether, tetrahydrofuran, and dioxane, ketone-based such as acetone, hydrocarbon-based such as toluene and hexane, halide-based such as chloroform, and high-boiling aprotic-based such as dimethylacetamide, dimethylformamide, dimethyl sulfoxide, and acetonitrile can be mentioned.

[0029] The second pipe (pipe) 101 has a tapered portion 30 whose pipe diameter narrows from the side of the dispersion tank 103 toward the side of the liquid feed pumps 120 and 121. In the tapered portion 30, when the pipe diameter on the side of the circulation pump 120 is D1 and the pipe diameter on the side of the dispersion tank 103 is D2, the relationship D1 < D2 is satisfied. More preferably, D1 < 1.1×D2, and even more preferably, D1 < 2×D2 is satisfied. If D1 < D2, the flow velocity in the pipe on the circulation pump side becomes faster than the flow velocity in the pipe on the dispersion tank side. Thereby, the mixing of coarse particles among the particles having a particle size distribution can be suppressed by the tapered portion 30, and further, by circulating the particle dispersion liquid to be fed more, sedimentation can be suppressed, and the amount of the dispersion liquid required for feeding can be reduced.

[0030] Furthermore, particles with a particle diameter of d1 or more in the particle size distribution are defined as coarse particles, and the particle density of the coarse particles is ρ s , the solvent density of the dispersion liquid is ρ l , the viscosity is μ, and the flow rate of the circulation pump is Q. Then, the following formula (1) 2.0×d1^2×(ρ s - ρ l ) > μ×Q / D2^2 (1) further suppresses the flow of coarse particles with a particle diameter of d1 or more into the tapered portion 30 of the second pipe 101. By satisfying the above formula (1), the feeding of coarse particles from the dispersion tank 103 can be suppressed, and further, the entry into the microchannel for microflow synthesis can be prevented. The tapered portion 30 of the second pipe 101 may be arranged in a direction intersecting the liquid level of the dispersion tank 103. Furthermore, the tapered portion 30 may be arranged vertically upward. By arranging the tapered portion 30 of the second pipe 101 in a direction intersecting the liquid level of the dispersion tank 103, the effect of suppressing coarse particles according to the above formula (1) can be obtained, and further, the feeding of coarse particles can be suppressed.

[0031] In such a microchannel, the flow is laminar, and sedimentation is discussed using Stokes' law. From Stokes' law, when considering the forces acting on the particles, if gravity overcomes the resistance force and the buoyancy force, the particles are considered to settle. Rearranging according to this equation, the particle diameter, density, flow rate, and pipe diameter have the above-described relationship. By satisfying this relational expression (1), the mixing of coarse particles can be further suppressed.

[0032] The pipe diameter D1 on the liquid feed pump 120, 121 side in the tapered portion 30 is preferably in the range of 0.25 mm or more and 9.0 mm or less. More preferably, it is 0.5 mm or more and 9.0 mm or less, and even more preferably, it is 0.5 mm or more and 8.5 mm or less. When it is smaller than 0.25 mm, there is a high possibility that particles of about 50 μm will also cause blockage. When it is larger than 9.0 mm, it may deviate from the laminar flow region and the above relational expression (1) may not hold.

[0033] The pipe diameter D2 on the dispersion liquid tank 103 side in the tapered portion 30 is preferably in the range of 1.0 mm or more and 9.5 mm or less. More preferably, it is 1.5 mm or more and 9.5 mm or less, and even more preferably, it is 2.0 mm or more and 9.5 mm or less. When it is smaller than 1.0 mm, there is a high possibility that the mixing of particles of about 50 μm cannot be suppressed. When it is larger than 9.5 mm, similar to the case of the pipe diameter D1, it may deviate from the laminar flow region and the above relational expression (1) may not hold.

[0034] <Particle Concentration Evaluation Unit> The particle concentration evaluation unit 200 is not particularly limited as long as it is an evaluation device capable of measuring the concentration of particles in the particle dispersion liquid. For example, it can be evaluated by transmittance, ultrasonic waves, etc.

[0035] <Control Unit> The control unit 300 is not particularly limited as long as it is a mechanism capable of control. However, feedback is performed based on the result of measuring the calibration curve of the particle concentration of the particle dispersion liquid in advance.

[0036] <Coarse Particle Suppression Unit> The coarse particle suppression unit 100 is constituted by a dispersion liquid tank 103, a circulation pump 120 and a dispersion liquid feed pump 121, and a second pipe 101. Note that the coarse particle suppression unit 100 only needs to include a dispersion liquid tank 103 and a second pipe 101. In order to fill the dispersion liquid tank 103 with the particle dispersion liquid, for example, a first pipe (circulation pipe) 102 for feeding the dispersion liquid from the dispersion liquid feed pump 121 to the dispersion tank 103 may be used as needed. The first pipe 102 functions as a circulation pipe that returns a part of the particle dispersion liquid sucked from the second pipe 101 to the pumps 120 and 121 to the dispersion liquid tank 103. Note that in the liquid feeding device for the particle dispersion liquid according to the present disclosure, the first pipe is not essential. Further, in the above, the first pipe 102 is used as a circulation pipe, but it is not essential to circulate, and it is not limited to this. Instead of the circulation pipe, it may be used as a pipe for simply supplying the particle dispersion liquid to the dispersion liquid tank 103.

[0037] Hereinafter, examples and comparative examples in the experiments conducted by the inventors will be described.

[0038] (Example) The particle dispersion liquid was fed under the following conditions. A pulverized product of Ni(COD)2 (manufactured by Kanto Chemical Co., Inc.), which is a nickel catalyst, was used as the raw material fine particles, and the experiment was conducted under an Ar atmosphere. As a result of measuring the particle diameter of Ni(COD)2 with a particle size distribution meter, D50 was 11.4 μm.

[0039] As the liquid feeding device for the particle dispersion liquid, a particle dispersion liquid tank, a tube pump as the circulation pump, and a mono pump as the liquid feeding pump were used, and the transmittance was evaluated as the particle concentration evaluation unit. As the second pipe, a pipe having a tapered portion with a pipe diameter D1 on the liquid feeding pump side of 2 mm and a pipe diameter D2 on the dispersion liquid tank side of 8 mm was used, and the experiment was conducted according to the following procedure.

[0040] (1) Ni(COD)2 was pulverized in a mortar under an Ar atmosphere. (2) Dimethylacetamide was selected as the solvent, and a 35 wt% particle dispersion liquid was prepared. (3) The particle dispersion was circulated from the dispersion tank through the circulation pump, in the order of the liquid feed pump and the dispersion tank. The flow rate of the circulation pump was set at 10 ml / min. (4) Next, the particle dispersion was fed from the liquid feed pump. The flow rate of the liquid feed pump was set at 0.5 ml / min. (5) Thereafter, the evaluation was performed by the particle concentration evaluation unit.

[0041] <Particle Concentration Evaluation Unit and Control Unit> The particle dispersion after the particle concentration evaluation unit was sampled, and the particle concentration of the particle dispersion was measured by transmittance and evaluated by the difference from the stock solution. As a result, it was 0.00% after 1 minute, 0.01% after 10 minutes, and 0.08% after 30 minutes. Feedback was received from the result of the evaluation unit after 30 minutes, and the liquid was fed at a flow rate of 0.55 ml / min.

[0042] ■ Solids Concentration Evaluation The fed particle dispersion was sampled for 1 minute after 1 minute, 10 minutes, 30 minutes, and 40 minutes, and the solid content was determined. As a result, it was 0.18 g initially, 0.17 g after 10 minutes, 0.16 g after 30 minutes, and 0.18 g after 40 minutes.

[0043] (Comparative Example) In the second pipe in the example, the content was the same as that described in the example except that the pipe diameter D1 on the liquid feed pump side was 2 mm and the pipe diameter D2 on the dispersion tank side was 2 mm, that is, a pipe with a uniform pipe diameter of 2 mm throughout was used. Similarly, the evaluation was performed by the difference in the transmittance of the particle dispersion. As a result, it was 0.00% after 1 minute, 0.01% after 10 minutes, and the liquid feed pressure increased rapidly after 25 minutes, and the liquid feed was stopped.

[0044] ■ Solids Concentration Evaluation The fed particle dispersion was sampled for 1 minute after 1 minute and 10 minutes, and the solid content was determined. As a result, it was 0.17 g initially, 0.18 g after 10 minutes, and since the liquid feed pump was stopped after 30 minutes, the evaluation could not be performed.

[0045] In the comparative example, although the liquid feeding was stable immediately after the liquid feeding, a rapid pressure change occurred. When the particle size distribution of the particles was checked, it was found that particles with a particle diameter of 100 μm or more were contained at 0.7 percent. This is because the pipe diameter of the second pipe was the same as 2 mm throughout, so that coarse particles with a particle diameter of 100 μm or more were directly fed into the liquid feeding pump, and it is considered that the blockage was caused by the coarse particles.

[0046] On the other hand, in the example, no rapid pressure change was observed even after 40 minutes of liquid feeding, and the liquid feeding was stable. This is because the pipe diameter D1 of the second pipe is 2 mm and D2 is 8 mm, so it is considered that coarse particles are excluded and the particle dispersion can be circulated. Also, although the difference in transmittance is slightly large, this is considered to be due to a slight decrease in the particle concentration by excluding coarse particles. By feeding this back, it can be seen that the amount of solid components required for the reaction can be fed by increasing the liquid feeding amount by the amount by which the concentration has decreased. When the particle size distribution of the particles was checked, particles with a particle diameter of 100 μm or more were not observed.

[0047] From the above, even in the liquid feeding device for the particle dispersion according to the example, and even when coarse particles are mixed in, it is possible to stably feed the particle dispersion into the microchannel.

[0048] In the present disclosure, it includes appropriately combining any of the various embodiments and / or examples described above, and the effects possessed by each embodiment and / or example can be achieved.

Industrial Applicability

[0049] According to the liquid feeding device for the particle dispersion according to the present disclosure, even when coarse particles are mixed in the particle dispersion of the raw material, blockage does not occur, and the particle dispersion of the raw material can be fed in a stable flow state. Even when the raw material does not dissolve in the solvent during chemical synthesis, a flow-through microreactor can be used. The liquid feeding device for the particle dispersion according to the present disclosure can also be applied to liquid feeding into microchannels other than chemical synthesis.

Explanation of Symbols

[0050] 10 Liquid delivery device 20 Microchannel 30 Tapered portion 100 Coarse particle suppression section 101 Second pipe (pipe) 102 First pipe (circulation pipe) 103 Dispersion liquid tank 110 Second raw material tank 120 Circulation pump 121 Dispersion liquid delivery pump 122 Second raw material liquid delivery pump 130 Mixer 131 Reactor 140 Temperature regulator 200 Particle concentration evaluator 300 Control device 400 Coarse particles

Claims

1. A liquid feeding device for a particle dispersion in which particles having a particle size distribution are dispersed in a liquid, a dispersion tank containing the particle dispersion, a liquid feeding pump for feeding the particle dispersion, a pipe connected to the liquid feeding pump and sucking the particle dispersion from the dispersion tank, and comprising the pipe has a tapered portion whose pipe diameter narrows from the dispersion tank side to the liquid feeding pump side, and the pipe diameter D1 on the liquid feeding pump side in the tapered portion is smaller than the pipe diameter D2 on the dispersion tank side, satisfying the relationship D1 < D2, A liquid feeding device for a particle dispersion.

2. The liquid feeding device for a particle dispersion according to claim 1, wherein the tapered portion of the pipe is arranged in a direction intersecting the liquid level of the dispersion tank.

3. Taking particles with a particle diameter of d1 or more in the particle size distribution as coarse particles, and the particle density of the coarse particles as ρ ｓ , the solvent density of the particle dispersion as ρ ｌ , the viscosity as μ, and the flow rate of the liquid feeding pump as Q, then the following formula (1) 2.0 × d1^2 × (ρ ｓ - ρ ｌ ) > μ × Q / D2^2 (1) The liquid feeding device for a particle dispersion according to claim 1, wherein the flow of coarse particles with a particle diameter of d1 or more into the tapered portion of the pipe is suppressed.

4. an evaluation unit for measuring the particle concentration of the particle dispersion fed from the liquid feeding pump, a control unit for controlling the flow rate of the liquid feeding pump based on the particle concentration in the particle dispersion measured by the evaluation unit, and further comprising The liquid feeding device according to claim 1 or 2.

5. The liquid feeding device according to claim 1 or 2, wherein the particle diameter of the coarse particles is larger than 50 μm.

6. The pipe diameter D2 on the dispersion liquid tank side is 1.0 mm or more and 9.5 mm or less. The liquid feeding device according to claim 1 or 2.

7. The liquid feeding device for a particle dispersion liquid according to claim 1, further comprising a circulation pipe for returning a part of the particle dispersion liquid sucked from the pipe to the dispersion liquid tank.

8. The particles are particles of a raw material for microflow synthesis, The liquid feeding device for a particle dispersion liquid according to claim 1, which feeds the particle dispersion liquid from the liquid feeding pump to the microchannel for microflow synthesis.

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