JP2010075844A - Method for recovering catalyst and microreactor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for recovering a catalyst which can continuously recover the catalyst after a reaction with a fluidized catalyst, and to provide a microreactor. <P>SOLUTION: The method for recovering the catalyst includes a reaction process of feeding a reaction liquid containing the catalyst in a micro-channel, a growth process of growing up catalyst particles by joining a catalyst separating liquid to the reaction liquid, and a recovering process of recovering the grown catalyst particles. The microreactor includes a first micro-channel feeding the reaction liquid containing the catalyst and an object which reacts with the catalyst, a second micro-channel feeding the reaction liquid and a catalyst separating liquid, and a recovering channel recovering the grown catalyst particles from the second micro-channel. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a catalyst recovery method and a microreactor.

  In chemical reactions, reaction catalysts are widely used for the purpose of mild reaction conditions and improving the reaction rate and selectivity. In addition, the reaction catalyst is recovered after completion of the reaction.

In Patent Document 1, a higher fatty acid or an alkali metal salt thereof and a general formula (C ₆ H ₅ ) ₂ P—R—O (CH ₂ ) _n COOH (where P is a p-phenylene group, and n is 6 Water in which rhodium halide and triphenylphosphine are sequentially added to and reacted with an organic solvent suspension of magnetite fine particles adsorbed with a carboxylic acid represented by (18) or an alkali metal salt thereof. A method for producing a catalyst for addition is disclosed, and a method for separating the catalyst by applying a magnetic field to the reaction mixture after the hydrogenation catalyst obtained by the above method is used for a hydrogenation reaction is disclosed. .
Patent Document 2 discloses that a) a catalyst metal colloid is concentrated on a filter as a precipitate; b) a filter containing the precipitate is incinerated to form ash, and the catalyst metal of the catalyst metal colloid is oxidized. C) and thereafter recovering the catalytic metal from the ash, a method of recovering the catalytic metal from the fluid is disclosed.

JP-A-5-64744 Japanese Patent Laid-Open No. 2003-247028

  An object of the present invention is to provide a catalyst recovery method capable of continuously recovering a catalyst after a reaction using a fluidized catalyst, and a microreactor.

The above-described problems of the present invention have been solved by the means described in <1> and <7> below. It is described below together with <2> to <6> and <8> to <11>, which are preferred embodiments.
<1> A reaction step in which a reaction liquid containing a catalyst is sent in a microchannel, a growth step in which a catalyst separation liquid is joined to the reaction liquid to grow catalyst particles, and a recovery in which the grown catalyst particles are recovered A process for recovering the catalyst, comprising a step,
<2> The catalyst recovery method according to <1>, wherein the specific gravity of the catalyst separation liquid is larger than the specific gravity of the reaction liquid,
<3> The above <1, wherein the catalyst includes at least one selected from the group consisting of titanium dioxide, tin oxide, and surface modification products thereof, and platinum, nickel, palladium, and coordination compounds thereof. > Or the method for recovering a catalyst according to <2> above,
<4> The method for recovering a catalyst according to any one of <1> to <3> above, wherein the catalyst separation liquid contains a pH adjuster.
<5> The method for recovering a catalyst according to any one of <1> to <3> above, wherein the catalyst separation liquid contains a surfactant or a flocculant.
<6> The method for recovering a catalyst according to any one of <1> to <5> above, wherein the catalyst separation liquid deposits only the catalyst metal component from the reaction liquid.
<7> A first microchannel for feeding a reaction liquid containing a catalyst and an object that reacts in the presence of the catalyst, and a second microchannel for feeding the reaction liquid and a catalyst separation liquid A microreactor having a recovery channel for recovering the grown catalyst particles from the second microchannel,
<8> The above-mentioned <7>, which has a microchannel for feeding a first liquid containing a catalyst and a microchannel for feeding a second liquid containing an object that reacts in the presence of the catalyst. Microreactor,
<9> The microreactor according to the above <7> or the above <8>, which has a micro flow path for feeding a catalyst separation liquid.
<10> The microreactor according to any one of <7> to <9> above, wherein the flow path width of the recovery flow path is determined by a diffusion equation,
<11> The microreactor according to any one of <7> to <10>, wherein the catalyst separation liquid joins the reaction liquid from below in the vertical direction.

According to the invention described in <1> above, the catalyst particles can be continuously recovered as compared with the case where the present configuration is not provided.
According to the invention described in the above <2>, the catalyst particles can be easily recovered as compared with the case where this configuration is not provided.
According to the invention described in the above <3>, the growth of the catalyst particles is easy and the recovery rate of the catalyst particles is excellent as compared with the case where this configuration is not provided.
According to the invention described in the above <4>, the catalyst can be easily grown to a particle size that can be recovered as compared with the case where this configuration is not provided.
According to the invention described in the above <5>, the catalyst can be easily grown to a particle size that can be recovered as compared with the case where this configuration is not provided.
According to the invention described in the above <6>, the catalyst can be recovered more efficiently than when the present configuration is not provided.
According to the invention described in <7>, it is possible to provide a microreactor capable of continuously collecting catalyst particles as compared with the case where the present configuration is not provided.
According to the invention described in <8> above, it is possible to provide a microreactor that is more excellent in recovery efficiency than when the present configuration is not provided.
According to the invention described in <9> above, it is possible to provide a microreactor that is more excellent in recovery efficiency than when the present configuration is not provided.
According to the invention described in <10> above, it is possible to provide a microreactor with higher recovery efficiency than when the present configuration is not provided.
According to the invention described in <11> above, it is possible to provide a microreactor that is more excellent in recovery efficiency than when the present configuration is not provided.

The catalyst recovery method of the present embodiment includes a reaction step in which a reaction liquid containing a catalyst is sent in a microchannel, a growth step in which a catalyst separation liquid is joined to the reaction liquid to grow catalyst particles, and a growth A recovery step of recovering the catalyst particles.
Further, the microreactor of the present embodiment is a second micro-channel for feeding a reaction liquid containing a catalyst and an object that reacts with the catalyst, the reaction liquid, and a catalyst separation liquid. It has a microchannel and a recovery channel for recovering the grown catalyst particles from the second microchannel.

(Catalyst recovery method)
The catalyst recovery method of this embodiment includes (1) a reaction step in which a reaction solution containing a catalyst is sent in a microchannel, and (2) a catalyst separation solution is joined to the reaction solution to grow catalyst particles. A growth step, and (3) a recovery step of recovering the grown catalyst particles.
Hereinafter, each process will be described.

(1) Reaction process In a reaction process, the reaction liquid containing a catalyst is sent in a micro channel. The reaction proceeds in the presence of the catalyst while being fed through the microchannel. In the present embodiment, the reaction is allowed to proceed in the presence of a catalyst in advance, and the reaction solution after completion of the reaction may be sent. However, it is preferable to advance the reaction while sending the liquid in the microchannel. The reaction in the microchannel is preferable because the reaction proceeds more uniformly and the target reaction can be performed efficiently.

<Microchannel>
As the micro channel for feeding the reaction solution, a channel having a width of several to several thousand μm (equivalent circle channel diameter) is preferably used. In the catalyst recovery method of the present embodiment, since the microchannel is microscale, both the size and the flow velocity are small, and the Reynolds number is 2,300 or less. Therefore, in the micro flow channel, the turbulent flow control is not performed as in the normal flow channel, but the laminar flow control is performed.
Here, the Reynolds number (Re) is expressed by the following formula, and when it is 2,300 or less, the laminar flow is dominant.
Re = uL / ν (u: flow velocity, L: representative length, ν: kinematic viscosity coefficient)

  In the present embodiment, the equivalent diameter (circular equivalent channel diameter) of the microchannel is preferably 5 mm or less, more preferably 1 mm or less, still more preferably 0.8 mm or less, and Particularly preferably, it is 5 mm or less. Further, it is preferably 0.1 mm or more, more preferably 0.2 mm or more, and further preferably 0.3 mm or more. It is preferable for the equivalent diameter of the microchannel to be within the above range because the channel is less likely to be clogged and the laminar flow can be controlled.

<Catalyst>
In general, the catalyst is roughly classified into a homogeneous catalyst used in a solution or dispersed and a heterogeneous catalyst used in a solid phase.
The heterogeneous catalyst is a catalyst in which the catalyst forms a separate phase from the reaction system, and most of the reaction system is a gas phase or a liquid phase using a solid catalyst, and is also called a solid catalyst. Compared to homogeneous catalysts, it is easier to separate and reprocess the catalyst from the product, but the catalytic action is limited to the solid surface, and the processes of adsorption of reactive molecules, surface reaction, and desorption of reaction products are It has a great influence on the effectiveness of the catalyst.
On the other hand, a homogeneous catalyst is a catalyst in which a reactant phase and a catalyst phase act in a uniform phase, and a gas phase homogeneous system such as NO, Br ₂ , or I ₂ that acts in reactions such as decomposition and oxidation in the gas phase. In addition to the catalyst, acid, base catalyst acting in the gas phase / liquid phase, soluble metal salts acting mainly in the liquid phase, metal fine particles such as metal complexes, and enzymes can be exemplified.
In the present embodiment, the catalyst is a homogeneous catalyst, and is preferably a metal catalyst containing a soluble metal salt and metal fine particles.

In this embodiment, as the catalyst, titanium dioxide, tin oxide, titanium dioxide, and surface modified products of these (titanium oxide, tin oxide, titanium dioxide), platinum, nickel, palladium, and them (platinum, nickel, Palladium) is a coordination compound. These may be used alone or in combination of two or more.
Among these, a coordinated palladium catalyst and a titanium oxide catalyst are preferable from the viewpoint of growing into catalyst particles in the growth step.

The palladium catalyst includes all those used as a palladium catalyst in this field, but those derived from Pd (0), Pd (I), and Pd (II) are preferred.
Pd (0) -derived materials include Pd (0) itself (which does not have a ligand or the like) and a Pd (0) complex coordinated with a ligand. Are, for example, [dichloro-μ-bisbis (dimethylphosphino) methane] diparadiu (Pd ₂ Cl ₂ [(CH ₃ ) ₂ PCH ₂ P (CH ₃ ) ₂ ] ₂ ), dichloro-μ-bisbis [(diphenylphos Fino) methane] dipalladium (Pd ₂ Cl ₂ [Ph ₂ PCH ₂ PPh ₂ ] ₂ ) and the like, and examples of those derived from Pd (II) include Pd (II) salts, which include For example, Pd (II) halides (chlorides, bromides, iodides, etc.), Pd (II) carboxylates (eg acetates and propionates) and the like are included. Of these, Pd (0) and Pd (II) salts are preferred, and Pd (0) is more preferred.

Examples of the ligand of the Pd (0) complex include 1,5-cyclooctadiene (COD), dibenzylideneacetone (DBA), bipyridine (BPY), phenanthroline (PHE), benzonitrile (PhNC), and isocyanide (RNC). ), Triethylarsine (As (Et) ₃ ); dimethylphenylphosphine (P (CH ₃ ) ₂ Ph), diphenylphosphinoferrocene (dPPf), trimethylphosphine (P (CH ₃ ) ₃ ), triethylphosphine (P (Et) ) _3), tri-tert- butylphosphine (P (tBu) _3), tricyclohexylphosphine (PCy _3), trimethoxy phosphine (P (OCH _{3) 3),} triethoxy phosphine (P (OEt) _3), tri tert - butoxy phosphine (P (OtBu) _3), triphenyl Sufin (PPh _3), 1,2-bis (diphenylphosphino) ethane (DPPE), organic phosphine ligands such as tri-phenoxy phosphine (P (OPh) ₃₎ can be mentioned, among them organic phosphine ligand Triphenylphosphine, tritert-butylphosphine, triethylphosphine, trimethylphosphine and the like are particularly preferable. Of these, triphenylphosphine is more preferable.
When the palladium catalyst is Pd (0) having a ligand, the number of ligands varies depending on the type of linear organic polymer compound used in the preparation, the crosslinking reaction conditions, etc., but usually 1 It is also possible to use ˜4 particles, or those supported on fine particles (for example, SiO ₂ , Al ₂ O ₃ , activated carbon, etc.) which are not related to the single substance or reaction.

The titanium oxide catalyst used in this embodiment includes all those used as a titanium oxide catalyst in this field. Specifically, the titanium oxide catalyst has a crystal structure of anatase type, rutile type or brookite type. Titanium is used. In particular, anatase type fine particle catalysts widely used as photocatalysts are suitable for many reactions. The titanium oxide catalyst may be used alone, or catalyst particles having improved dispersibility by supporting them on fine particles (for example, SiO ₂ , Al ₂ O ₃ , activated carbon, etc.) that are not involved in the reaction may be used.

In the case where metal fine particles are supported on the surface of inorganic fine particles and polymer fine particles to function as a catalyst, the supported mother particles include SiO ₂ , Al ₂ O ₃ , ZnO, TiO ₂ , CaTiO ₃ , activated carbon, polystyrene, and the like. In particular, when an aqueous solvent is used, porous SiO ₂ is preferable because it has a large surface area and fine particles can be obtained.

<Reaction solution>
In the present embodiment, the reaction liquid includes at least a catalyst and an object that reacts in the presence of the catalyst, and the object to be reacted is not particularly limited.
For example, as an example of using a palladium catalyst, Mizoroki-Heck reaction for synthesizing substituted olefins by cross-coupling aryl / alkenyl halides with terminal olefins, Suzuki for cross-coupling organic boron compounds and organic halogen compounds. Examples include a -Miyaura Cross Coupling reaction, a Migita-Kosugi-Stille Cross Coupling reaction in which cross-coupling is performed between an organic halide or organic triflate and an organic tin compound.

Moreover, decomposition | disassembly of an organic compound can be illustrated as an example which uses a titanium oxide catalyst. That is, the reaction which decomposes | disassembles an organic compound can be illustrated by irradiating light, sending the reaction liquid containing a titanium oxide and an organic compound.
In addition, it can select suitably from well-known reaction using a homogeneous catalyst, and is not specifically limited.

  The catalyst in the reaction solution may be in the form of particles or may be dissolved, and is not particularly limited, but the volume average particle diameter is preferably 10 μm or less, and more preferably 3 μm or less. When the volume average particle diameter is 10 μm or less, it is preferable that a general flow path size does not cause clogging, and since the specific surface area is large, the reaction proceeds quickly. In addition, the aspect whose volume average particle diameter is 10 micrometers or less includes the case where the catalyst is melt | dissolving.

In addition to the catalyst and the target that reacts with the catalyst, it is preferable to contain a solvent, and from the viewpoint of feeding the liquid in the microchannel, the viscosity of the reaction solution is preferably 1 to 200 mPa · s, More preferably, it is 1-80 mPa * s. What is necessary is just to select the solvent to be used suitably so that it may become said viscosity.
It does not specifically limit as a solvent, It can select suitably from well-known solvents used for reaction, such as water (ion-exchange water, distilled water), MEK (methyl ethyl ketone), THF (tetrahydrofuran), ethyl acetate.
Moreover, it is preferable to appropriately select the pH, temperature, etc. of the reaction solution according to the required reaction conditions.

The reaction solution feeding speed is not particularly limited and can be appropriately selected according to the channel diameter of the microchannel, the intended recovery rate, etc., but is preferably 0.001 to 100 ml / h, More preferably, it is 0.01 to 50 ml / h. It is preferable for the liquid feeding speed to be within the above-mentioned range since clogging of the flow path is unlikely to occur and the processing speed is excellent.
The reaction solution is preferably pumped into the microchannel by a microsyringe, rotary pump, screw pump, centrifugal pump, piezo pump or the like.

  The reaction liquid may be fed into the micro flow path by two flow paths that introduce the catalyst-containing liquid and the liquid containing the object that reacts with the catalyst in advance, or the catalyst and the object that reacts with the catalyst in advance A reaction solution containing a product can be prepared and sent to a microchannel, and is not particularly limited.

(2) Growth Step The growth step is a step for growing catalyst particles by joining the catalyst separation liquid to the reaction liquid.
In the present embodiment, the growth step is not particularly limited as long as the catalyst separation liquid is joined to grow the catalyst in the reaction liquid into catalyst particles larger than the catalyst in the reaction liquid.
The particle diameter of the grown catalyst particles is not particularly limited, but is preferably a size that allows separation of the catalyst, and the volume average particle diameter is preferably 30 μm or more, and more preferably 50 μm or more. Moreover, it is preferable that it is 200 micrometers or less, and it is more preferable that it is 100 micrometers or less.
It is preferable that the volume average particle diameter of the grown catalyst particles is 30 μm or more because the particle diameter is suitable for recovery and the recovery of the catalyst particles is easy. Further, it is preferable that the volume average particle diameter of the catalyst particles is 1/10 or less of the equivalent circle diameter of the flow path because clogging of the flow path is difficult to occur.

The growth step may promote catalyst particle growth at the interface between the catalyst separation liquid and the reaction liquid by joining the catalyst separation liquid and the reaction liquid in a laminar flow state. After merging, the catalyst separation liquid and the reaction liquid are mixed and sent, for example, by applying ultrasonic vibration from outside the flow path, vibrating the flow path, or providing a baffle plate in the flow path. There may be, and it is not specifically limited.
The catalyst separation liquid is preferably fed by a microsyringe, a rotary pump, a screw pump, a centrifugal pump, a piezo pump, etc., and the preferred liquid feeding speed is the same as in the above-described reaction liquid flow. is there.

<Catalyst separation liquid>
The catalyst separation liquid is not particularly limited as long as it can grow into catalyst particles larger than the catalyst in the reaction liquid by joining the fine flow path through which the reaction liquid containing the catalyst is fed. It is preferable to select appropriately according to the catalyst and reaction system to be used.
Specifically, an embodiment in which the catalyst separation liquid includes a pH adjusting agent, and an embodiment in which either the surfactant or the flocculant is included can be exemplified.

The catalyst separation liquid may be one that agglomerates the catalyst particles in the reaction liquid into larger catalyst particles, or deposits with a size of 30 μm or more that can sufficiently recover only the catalyst metal component from the reaction liquid, Further, any method such as a method of aggregating the precipitated particles to a size of 30 μm or more may be used.
When only the catalyst metal component is deposited from the reaction solution, the catalyst is in a dissolved state in the reaction solution, and is grown into catalyst particles by depositing the catalyst metal component.

  When a coordination palladium catalyst is used as the catalyst, it is known that the coordination palladium catalyst dissolves in water and an organic solvent, but deactivated zero-valent metal palladium does not dissolve. Therefore, in the case of using a coordination palladium catalyst, when the reaction solution after the reaction is deactivated, metal palladium is precipitated and can be recovered.

In general, the electrostatic repulsive force is weakened near the isoelectric point, so that the particles tend to aggregate. Therefore, when a metal particle catalyst is used, the particle size can be increased by adjusting the pH to be close to the isoelectric point of the metal particle.
When the catalyst separation liquid contains a pH adjuster, the pH adjuster is not particularly limited, and any of an inorganic acid, an inorganic base, an organic acid, or an organic base can be used.

Further, the catalyst separation liquid may contain a surfactant or a flocculant.
Surfactants include sulfate, sulfonate, phosphate, and soap anionic surfactants; amine and quaternary ammonium salt and other cationic surfactants; and polyethylene Nonionic surfactants such as glycol-based, alkylphenol ethylene oxide adduct-based, polyhydric alcohol-based and the like can be exemplified. As the aggregating agent, polyaluminum chloride aqueous solution (PAC), aluminum sulfate aqueous solution (sulfuric acid band), Examples thereof include an aqueous ferric chloride solution, and it is preferable to select appropriately according to the purpose.

  Specifically, a combination of a polystyrene resin dispersion and a polyaluminum chloride aqueous solution, or a combination of a polyester resin and an aluminum sulfate aqueous solution can be preferably exemplified.

  Moreover, it is also preferable that the specific gravity of the catalyst separation liquid is larger than the specific gravity of the reaction liquid. In this case, it is possible to form a stable interface by sending the reaction solution upward in the micro flow channel and sending the catalyst separation solution downward in the micro flow channel to form a laminar flow. preferable. Further, when the specific gravity of the grown catalyst particles is heavier than that of the catalyst separation liquid, it is preferable because the catalyst particles can be recovered by utilizing the sedimentation reaction of the catalyst particles.

(3) Recovery step In the present embodiment, in the recovery step, the grown catalyst particles are recovered.
The method of recovery is not particularly limited, and can be recovered by filtration (filtration) or concentrated more than the concentration of catalyst particles sent in the growth process, that is, the concentration of catalyst particles in the growth process. The catalyst particle dispersion may be recovered.

  In the recovery step, the catalyst particles may be concentrated and recovered by utilizing the sedimentation or floating of the catalyst particles. For example, a method described in JP-A-2006-116520 can be exemplified. Further, the catalyst particles may be recovered by causing electrolysis in a direction crossing the flow path. For example, a method described in JP-A-2006-187770 can be exemplified. In addition, a method of collecting a particle using a centrifugal force by providing a bent portion in a micro flow path can be exemplified. -FILTER WITH SPIRAL CHANNEL ", IEEE TRANSDUCERS & EUROSENSORS 2007 (The 14th International Conference on Solid-State Sensors, Actuators and Microsystems), pp.1865-1868.

In this embodiment, it is also preferable to provide a recovery flow path for recovering the grown catalyst particles downstream of the micro flow path for feeding the catalyst separation liquid and the reaction liquid. Moreover, it is preferable to determine the channel width of the recovery channel by a diffusion equation.
The general solution of the diffusion equation is given by

When two kinds of solutions are laminarly flowed in the horizontal direction, it is considered that the point of maximum concentration moves so that the position of 50% concentration always becomes the center of the flow path.
If the catalyst particles are branched and collected at a position where the diffusion is zero, and the catalyst particles are aggregated and / or precipitated at the interface between the catalyst separation liquid and the reaction liquid, the catalyst particles which are theoretically completely aggregated and / or precipitated should be recovered. Can do.

This will be described with reference to the drawings.
The left diagram of FIG. 1 is a plan view of a microreactor in which the channel width of the recovery channel is determined by a diffusion equation. The reaction liquid and the catalyst separation liquid are respectively sent to a rectangular flow path having a width and height of 1.0 mm, merged by a Y-shaped flow path, and fed by a 50 mm long merge flow path in a laminar flow state. Yes.
The right diagram in FIG. 1 shows the relative concentration at the point Ymm from the merge. Here, since the flow path length is 50 mm, if attention is paid to the curve of Y = 50 mm, the relative density is 0 at about 0.15 mm from the width center of the flow path. Accordingly, in the left diagram of FIG. 1, if the left side from the point of 0.15 mm from the interface between the catalyst separation liquid and the reaction liquid is recovered as the catalyst recovery liquid, the catalyst particles generated at the interface can be recovered almost completely. .

(Microreactor)
The microreactor of the present embodiment includes a first microchannel that sends a reaction liquid containing a catalyst and an object that reacts in the presence of the catalyst, a second microchannel that sends the reaction liquid, and a catalyst separation liquid. And a recovery channel for recovering the grown catalyst particles from the second micro channel.
FIG. 2 is a conceptual schematic diagram showing one embodiment of the microreactor 1 of this embodiment.
The first liquid A containing the catalyst is sent through the micro flow path 2, and the second liquid B containing the object that reacts in the presence of the catalyst is sent through the micro flow path 3. The A liquid and the B liquid are mixed by, for example, the collision type micromixer 4, and the reaction liquid C that is the mixed liquid is fed to the first microchannel 5. The length of the first microchannel 5 is preferably determined as appropriate according to the time required for the reaction. In addition, the first microchannel 5 can be heated, stirred (mixed) or the like according to the reaction conditions, and it is preferable to select the liquid feeding conditions as appropriate according to the desired reaction conditions. In FIG. 2, the catalyst 10 is contained as a catalyst.
After sufficient reaction, the catalyst separation liquid D is sent to the reaction liquid C in the first microchannel 5. The catalyst separation liquid D is sent to the second microchannel 7 via the catalyst separation liquid introduction path 6.
In the second microchannel 7, the reaction liquid C and the catalyst separation liquid D are sent under laminar flow. In FIG. 2, the aggregation of the catalyst 10 occurs at the interface between the reaction liquid and the catalyst separation liquid, and grows to catalyst particles 11 having a particle diameter larger than that of the catalyst 10. The catalyst particles 11 are recovered through the recovery flow path 8, and the reaction liquid is recovered from the reaction liquid recovery flow path 9. Thereby, the catalyst in the reaction liquid C can be recovered.
In FIG. 2, the first liquid A containing the catalyst and the second liquid B containing the target that reacts with the catalyst are fed and mixed, respectively, but this embodiment is limited to this. There is no particular limitation, and the first liquid A and the second liquid B may be mixed in advance and then the reaction liquid C may be sent to the first microchannel. Moreover, as a catalyst, a reaction liquid, and a catalyst separation liquid, each described with the collection | recovery method of this embodiment can be used conveniently.

  Hereinafter, although this embodiment is described concretely based on an example, this embodiment is not limited to an example. In the examples, “part” means “part by weight” unless otherwise specified.

<Example 1>
In Example 1, after performing Suzuki-Miyauchi Coupling reaction, the palladium catalyst was deposited and recovered.
FIG. 3 is a conceptual diagram of the configuration of the microreactor used in Example 1.
The following A liquid, B liquid, C liquid, and D liquid were sent at 60.0 ml / h.
Solution A: 0.1 mol / L bromobenzonitrile-containing THF (75%) solution Solution B: 0.1 mol / L 4-phenylboronic acid-containing THF (75%) solution Solution C: Catalyst (Pd / SiO ₂ catalyst, center 0.1 mol / L NaHCO ₃ solution in which particle size: 2.5 μm) is dispersed at 10 wt% D solution: 0.2 mol / L HNO ₃ solution

Liquid A (60.0 ml / h) is sent to the IMM micromixer 32 via the microchannel 30 and liquid B (60.0 ml / h) is sent to the micromixer 32 manufactured by IMM. The mixture was mixed by the mixer 32, and the mixture was fed to the microchannel 33 (φ1.0 mm, length 0.5 m, Teflon (registered trademark) tube).
Next, the liquid C is sent to the central collision type microreactor (Kinetic-energy Mixing Reactor) 34 through the micro channel 35 (60.0 ml / min), and the liquid mixture of liquid A and liquid B, liquid C, Were mixed. The liquid mixture (reaction liquid) of the liquid A to liquid C was fed to the first microchannel 36 (φ1.0 mm, length 3.0 m, SUS tube). The first microchannel 36 was heated and held at 75 ° C. with a heater 37 to complete the Suzuki-Miyauchi Coupling reaction.
Thereafter, when the temperature becomes 30 ° C. or lower, the liquid D is sent (60.0 ml / h) through the micro flow path 38, so that the reaction liquid and the upper and lower laminar flow fields become the second. The liquid was fed into a micro flow path 39 (φ1.0 mm, length 2.5 m, Teflon (registered trademark) tube). The reaction solution was fed so as to be an upper layer and the D solution was a lower layer.
The Pd / SiO ₂ fine particles contained in the liquid C aggregate and precipitate on the liquid D side because the pH of the interface is 7.0 to 9.3. On the other hand, the biphenyl compound as the reaction product is present dissolved in the THF side (upper layer). Therefore, the target product can be obtained by separating and collecting the upper layer from the microchannel 41 (120.0 ml / h) and distilling the upper layer. On the other hand, the water-soluble liquid containing Pd could be recovered from the lower recovery channel 40 (120.0 ml / h).
Here, the average particle diameter of Pd / SiO ₂ particles contained in the lower layer was 35 [mu] m.

<Example 2>
In Example 2, a palladium catalyst was synthesized in a microchannel, and thereafter, a Suzuki-Miyauchi Coupling reaction was performed using the catalyst, and the catalyst was recovered (separated) after the reaction.
FIG. 4 is a conceptual diagram of the configuration of the microreactor 50 used in the second embodiment.
The following liquid A to liquid F were used.
Liquid A: Palladium chloride (II) at 140 ° C. + triphenylphosphine + dimethyl sulfoxide (0.1: 0.5: 17 (molar ratio)) (liquid feeding speed 60.0 ml / h)
Liquid B: hydrazine hydrate (dropping rate 0.024 mol / h)
C liquid: 0.1 mol / L blu benzonitrile water-containing THF (75%) solution (liquid feeding speed: 150 ml / h)
Solution D: 0.1 mol / L 4-phenylboronic acid-containing THF (75%) solution (feed rate: 150 ml / h)
Liquid E: ion-exchanged water (liquid feeding speed: 600 ml / h)
Liquid F: ethyl acetate solution (liquid feeding speed: 300 ml / h)

Liquid B is dropped into liquid A heated to 140 ° C. in microchannel 51 through microchannel 52, and microchannel 53 (φ1.0 mm, length 2 m, Teflon (registered trademark) tube) is fed. By doing so, a Pd complex was synthesized. The solution was gradually cooled to 120 ° C., and the generated N ₂ was removed from the Y-shaped branched microchannel 54 with a settler by gas-liquid layer separation. Thus, the synthesis of Pd (PPh ₃ ) ₄ as a catalyst was completed in a state dissolved in a solvent.
The solution containing the catalyst was sent to a micro flow channel 55 (Teflon (registered trademark) tube having a diameter of 1.0 mm and a length of 3 m) and cooled to 75 ° C.
Next, liquid C is sent to the solution containing the catalyst via the micro flow path 56 and liquid D is sent via the micro flow path 57, and the mixture is subjected to collision-type mixing at 75 ° C. The solution was sent to a microchannel 59 (φ1.0 mm, length 3 m, Teflon (registered trademark) tube). This obtained the biphenyl compound in the state melt | dissolved in the solvent.

Next, the E liquid is sent through the micro flow path 60, the F liquid is sent through the micro flow path 61, and merges with the solution containing the biphenyl compound (biphenyl compound-containing solution) in a laminar flow field. The fine channel 62 was fed. The microchannel 62 is a triple tube type (center φ0.5 mm, length 1 m), and the E liquid was sent to the outermost periphery and the F liquid was sent to the center.
Since the solution E and the biphenyl compound-containing solution were mixed, fine particles of catalyst Pd and biphenyl that did not dissolve in the solution E were deposited. Since the F liquid is not miscible with other solvents, the aforementioned biphenyl compound and Pd particles are precipitated in the F liquid due to the influence of gravity. However, since the biphenyl compound is soluble in the F liquid, it dissolves in the F liquid. The liquid was separated under laminar flow and filtered (20 μm mesh nylon) to remove only Pd.
Moreover, the solvent of the remaining solution was volatilized and the target biphenyl compound was obtained.

  Here, when the solution was collected from the microchannel 59 before mixing with the liquid C and liquid D, the palladium complex was completely dissolved. On the other hand, the filtered catalyst had an average particle size of 42 μm.

  In addition, while polymerizing Pd so that the nanoparticles are embedded in the complex, polymer nanoparticles that have been grown only to a size suitable for the reaction are used as a catalyst, and after the reaction, the polymer is repolymerized and classified. It may be a method of collecting after growing to a size that can (or can be filtered).

<Example 3>
In Example 3, wastewater was purified using the microreactor of this embodiment.
FIG. 5 is a conceptual diagram of the microreactor 70 used in the present embodiment. FIG. 6 is a dimensional drawing (plan view) of the microreactor used in Example 3.
The toner cleaning liquid produced by the aggregation / unification method includes metal ions as impurities and residual organic substances remaining in the reaction process. Metal ions contained in the wastewater can be removed by an ion exchange membrane or the like, but organic substances are difficult to decompose.
In this embodiment, as can be dispersed in an aqueous, fine particles was supported TiO ₂ on the surface of the SiO ₂ (average particle diameter 1.2 [mu] m) as a catalyst, it was mixed with waste in the microchannel, the TiO ₂ photocatalyst The organic matter was decomposed by the effect.

  In addition, the microreactor used in Example 3 produced a flow path by processing a 0.5 mm groove on a glass substrate (thickness 2.5 mm), and the top of the glass substrate on which the groove (micro flow path) was formed. Then, a glass substrate (thickness: 1.0 mm) was diffusion bonded as a lid and produced.

C liquids were used from the following A liquids.
Liquid A: catalyst dispersion (pH 7.0, catalyst: SiO ₂ / TiO ₂ coat, average particle size 1.2 μm, 12 vol% aqueous dispersion)
B liquid: toner cleaning liquid C liquid: hypochlorous acid aqueous solution (pH 1.7)
In this example, the total flow rate of liquid A and liquid B was 100 ml / h, and the flow rate of liquid C was 100 ml / h.

  Liquid A containing catalyst fine particles is fed through the micro flow path 71, and liquid B as the toner cleaning liquid is fed through the micro flow path 72, mixed by the collision mixer 73, and mixed into the mixing flow path 74. Liquid was sent. The mixing channel 74 was irradiated with light, and the organic matter in the liquid B was decomposed using the photocatalytic reaction of titanium oxide.

After the photocatalytic reaction sufficiently progressed, the liquid C was sent through the micro flow path 75, and the reaction liquid and the liquid C were sent to the mixing flow path 76 in a laminar flow. Aggregation of catalyst particles occurred at the interface between the hypochlorous acid aqueous solution and the liquid mixture of liquid A and liquid B. The agglomerated catalyst particles were recovered through the recovery channel 77, and the reaction solution was discharged from the microchannel 78.
The width of the recovery channel was determined by a diffusion equation, and aggregated (growth) catalyst particles were recovered.
Note that the pH isoelectric point of the TiO ₂ fine particles is about 6.0, and aggregates because there is no repulsive force between the particles around pH 6, and when the particles are further away (for example, pH = 2 or pH = 12), The resilience increases and disperses. Generally, since it is required to disperse around pH 7, the isoelectric point is changed to pH _{2 to 4 by} coating the surface with SiO ₂ .
These phenomena are clarified by “DLVO theory”, and the explanation thereof is detailed in “Latest Pigment Dispersion Technology”, Technical Information Association, pages 67-74, (1993). In addition, the potential curve elucidated by the DLVO theory is expected to be as shown in FIGS. 7A and 7B at each pH.
In this example, by shifting the pH to about 2 using hypochlorous acid, the pH was set near the isoelectric point, the catalyst particles were aggregated, and could be grown to a size capable of filtering and the like. . The filtered catalyst particles had a volume average particle diameter of 32 μm.

It is the top view of the microreactor which determined the channel width of the recovery channel with the diffusion equation, and the graph which shows the relative concentration in the point of Ymm from the confluence. It is a conceptual schematic diagram which shows one embodiment of the microreactor of this embodiment. 1 is a conceptual diagram of a configuration of a microreactor used in Example 1. FIG. FIG. 3 is a conceptual diagram of the configuration of a microreactor used in Example 2. 6 is a conceptual diagram of a microreactor used in Example 3. FIG. 6 is a dimensional drawing (plan view) of a microreactor used in Example 3. FIG. It is a potential curve that is clarified by the DLVO theory.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Micro reactor 2, 3 Micro flow path 4 Collision type micromixer 5 1st micro flow path 6 Catalyst separation liquid introduction path 7 Second micro flow path 8 Recovery flow path 9 Reaction liquid recovery flow path 10 Catalyst 11 Catalyst particle 30, 31, 33, 35, 38, 41 Microchannel 32 Micromixer 34 Microreactor 36 First microchannel 37 Heater 39 Second microchannel 40 Recovery channel 50 Microreactors 51, 52, 53, 54, 55, 56 57, 59, 60, 61, 62 Microchannel 70 Microreactors 71, 72, 75, 78 Microchannel 73 Collision mixer 74 Mixing channel 76 Mixing channel 77 Recovery channel

Claims (11)

A reaction process in which a reaction solution containing a catalyst is sent in a micro-channel,
A growth step in which a catalyst separation liquid is joined to the reaction liquid to grow catalyst particles; and
And a recovery step of recovering the grown catalyst particles. A method for recovering a catalyst.   The catalyst recovery method according to claim 1, wherein the specific gravity of the catalyst separation liquid is larger than the specific gravity of the reaction liquid.   3. The catalyst according to claim 1 or 2, wherein the catalyst comprises at least one selected from the group consisting of titanium dioxide, tin oxide, and surface modification products thereof, and platinum, nickel, palladium, and coordination compounds thereof. The method for recovering the catalyst as described.   The method for recovering a catalyst according to any one of claims 1 to 3, wherein the catalyst separation liquid contains a pH adjuster.   The catalyst recovery method according to any one of claims 1 to 3, wherein the catalyst separation liquid contains a surfactant or a flocculant.   The method for recovering a catalyst according to any one of claims 1 to 5, wherein the catalyst separation liquid deposits only a catalytic metal component from the reaction liquid. A first microchannel for feeding a reaction liquid containing a catalyst and an object that reacts in the presence of the catalyst;
A second microchannel for feeding the reaction liquid and the catalyst separation liquid;
A microreactor comprising a recovery channel for recovering the grown catalyst particles from the second microchannel.   The microreactor according to claim 7, comprising a microchannel for feeding a first liquid containing a catalyst and a microchannel for feeding a second liquid containing an object that reacts in the presence of the catalyst.   The microreactor according to claim 7 or 8, further comprising a micro flow path for sending a catalyst separation liquid.   The microreactor according to any one of claims 7 to 9, wherein a channel width of the recovery channel is determined by a diffusion equation.   The microreactor according to any one of claims 7 to 10, wherein the catalyst separation liquid merges with the reaction liquid from below in the vertical direction.

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