KR20160133701A - Recoverable microcapsule with metal catalyst using microdroplet and preparation method thereof - Google Patents
Recoverable microcapsule with metal catalyst using microdroplet and preparation method thereof Download PDFInfo
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- KR20160133701A KR20160133701A KR1020150066557A KR20150066557A KR20160133701A KR 20160133701 A KR20160133701 A KR 20160133701A KR 1020150066557 A KR1020150066557 A KR 1020150066557A KR 20150066557 A KR20150066557 A KR 20150066557A KR 20160133701 A KR20160133701 A KR 20160133701A
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- B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
- B01J13/02—Making microcapsules or microballoons
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
- B01J13/02—Making microcapsules or microballoons
- B01J13/06—Making microcapsules or microballoons by phase separation
- B01J13/14—Polymerisation; cross-linking
- B01J13/18—In situ polymerisation with all reactants being present in the same phase
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- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
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Abstract
Description
The present invention relates to a method of preparing a reclaimable microcapsule in which a metal catalyst using a double droplet containing a metal catalyst in the form of a fine particle is embedded and a reclaimable microcapsule containing the metal catalyst prepared by the method, A method of producing a reclaimable microcapsule having metal catalyst incorporated therein by using metal catalyst nano-colloid particles in an inner droplet of a double droplet finely formed in a microfluidic device and using an oil containing a photopolymerizable functional group in an intermediate phase And a restorative microcapsule in which a metal catalyst produced therefrom is impregnated.
In the case of a catalyst used in a chemical reaction, there is a possibility that the activity of the catalyst is lost due to a sensitive reaction depending on the surrounding environment, so that a design is required to maintain the activity of the catalyst. The design of the catalyst improves the activity and usability of the catalyst and improves the activity and utilization of the catalyst so that the hydrogenation, alkene removal reaction, carbonylation, petroleum refining, Suzuki coupling reaction, Heck coupling reaction, Sonogashira coupling reaction, It is very important because it can be used in various chemical reactions such as Stille coupling reaction. More specifically, conventional active metal catalysts have been prepared in the form supported on carbon nanostructures, nanoparticles, films, and membranes and used in a wide range of chemical reactions. However, in the case of the active metal catalyst designed in the above-mentioned form, it has important defects such as sintering of the active metal site and side reaction of the catalytic reaction. When the metal supported catalyst contacts with other materials, And the catalyst activity is lost. As a result, a new catalyst has been actively researched to overcome the above problems.
Korean Laid-Open Patent Publication No. 2015-0010607 discloses a catalyst having a novel structure capable of producing a novel secondary structure of a carbon nanostructure and a catalyst having a novel structure prepared thereby. The catalyst of the new structure proposed by the prior art can be produced by carrying a metal catalyst precursor on a support of a sintered core-shell structure and then re-firing the core-shell support on which the catalyst is supported, - Although the metal catalyst supported on the shell support has improved the catalytic activity by improving the defects represented by the conventional metal catalyst, some active metal sites are still sintered, and the degree of improvement of catalytic activity is insignificant, Which is difficult to implement.
Also, in Korean Patent Registration No. 10-0987935, silica nanospheres, in which a heterodimer composed of magnetic metal oxide nanocrystals and noble metal oxide nanocrystals are encapsulated in a silica shell, are used to produce various magnetic metal oxide nanocrystals and noble metal nanocrystals Or alloy nanocrystals of a magnetic metal and a noble metal. The heterodimers and alloy nanocrystals suggested by the prior art can be prepared by encapsulating the magnetic metal oxide and the noble metal oxide in a silica shell by annealing a magnetic metal oxide and a noble metal oxide which can be used as a metal catalyst at a high temperature, The alloy nanocrystals of the core-shell type in the form of core-shell and the alloy nanocrystals of the noble metal minimize the possibility of occurrence of side reactions of the catalytic reaction and improve the recyclability of the metal catalyst. However, Such as the sintering of some active metal sites that occurs during the annealing process.
SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art as described above, and it is an object of the present invention to provide a process for producing a metal catalyst, which comprises metal catalyst nanocolloidal particles in an inner liquid through a microfluidic device, A simple process capable of stably storing a metal catalyst by forming a double droplet of a uniform size into which a catalyst is incorporated, and a process for preparing a restorative microcapsule containing a metal catalyst having remarkably improved catalytic activity, restorability and recyclability And a restorative microcapsule prepared according to the above method.
The term "microcapsule" in the context of the present invention is used to refer to a microcapsule having a size of micrometers, which incorporates a metal catalyst, unless otherwise specified.
The term "encapsulation" in the present specification is used to mean a process for producing a double droplet in which an aqueous dispersion solution containing metal-catalyzed nanocolloidal particles is used as an internal droplet, unless otherwise specified.
The present invention provides a method for preparing a water-dispersed solution comprising: (a) preparing an aqueous dispersion solution comprising metal-catalyzed nanocolloid particles and a polymeric surfactant; (b) an outer tube which is open on both sides, an intermediate tube which is present in one side of the outer tube, an inner tube which is present inside the intermediate tube, and an inner tube which is present on the other side of the outer tube, Wherein the intermediate tube and the inner tube have a shape of a nozzle whose inner diameter is decreased according to the flow direction of the fluid, wherein the flow of the aqueous dispersion solution into the inner tube and the flow of the water The flow of the oil containing the higher alcohol and the photopolymerizable monomer in the same direction as the flow of the dispersion solution and the flow of the continuous phase containing the polymer type surfactant in the direction opposite to the flow of the aqueous dispersion solution as the outer tube are introduced, Forming a double droplet of size; And (c) photopolymerizing the double droplet to prepare a microcapsule containing a metal catalyst in the form of a fine particle. The present invention also relates to a method for preparing the reclaimable microcapsule.
In the present invention, the step (a) comprises the steps of (1) mixing a metal ion complex with a polymer type surfactant and a volatile lower alcohol solvent to prepare a suspension; (2) applying microwave to the suspension and evaporating the volatile lower alcohol solvent to obtain stabilized metal catalyst nanoparticles; And (3) re-dispersing the metal catalyst nanoparticles in an aqueous solution containing a polymer type surfactant to prepare an aqueous dispersion solution containing the metal catalyst nanocolloid particles.
In the present invention, the polymer type surfactant in the step (a) may be any one selected from the group consisting of polyvinyl alcohol and polyvinyl pyrrolidone.
In the present invention, the metal ion complex of the step (1) may be at least one selected from the group consisting of silver, gold, titanium, zirconium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, iron, rubidium, osmium, nickel, rhodium, And at least one metal ion selected from the group consisting of metal ions.
In the present invention, the polymer type surfactant in the step (3) may be included in an amount of 5 to 20% by weight based on the total weight of the aqueous dispersion solution.
In the present invention, the metal catalyst nano-colloid particles may have a size of 1 to 1000 nm and may include 1 to 40% by volume of the total volume of the aqueous dispersion solution.
In the present invention, the photopolymerizable monomer may include at least two functional groups selected from the group consisting of an acrylate group, a cyanoacrylate group, an allyl group and an epoxy group in one molecule.
In the present invention, the continuous phase may include 5 to 20% by weight based on the total weight of the continuous phase of the polymer type surfactant.
The method for preparing the reclaimable microcapsule containing the metal catalyst of the present invention may be characterized by controlling the size and thickness of the polymer microcapsule by controlling the flow rate of the aqueous dispersion solution, the oil flow, and the continuous phase flow.
In the photopolymerization process of the step (c), the porous polymer membrane is formed by phase separation of the polymerized polymer and the higher alcohol.
The present invention is a microcapsule prepared from the method for preparing the reclaimable microcapsule in which the metal catalyst is incorporated, and includes a restorative microcapsule containing metal catalyst nanocolloid particles therein and having a porous polymer membrane form.
Also, the present invention includes a method of hydrogenating an organic compound using the reclaimable microcapsule in which the metal catalyst is incorporated as a catalyst.
The microcapsule of uniform size can be prepared by a simple process, which can stably store the metal catalyst having high catalytic activity without leakage to the outside of the microcapsule through the process for producing the reclaimable microcapsule containing the metal catalyst of the present invention have. In addition, through the microcapsule production method, not only the selective permeability through the pores existing in the capsule membrane of the microcapsule but also the high diffusion rate of the reactants and products can be maintained through the pore structure of the capsule membrane, It is possible to prepare microcapsules which can be used as a catalyst having catalytic activity as high as that of the catalyst. In addition, it is possible to manufacture microcapsules having excellent restorability that can be restored to their original form in a short time by rehydration by adding them to a solvent after drying through the above-mentioned microcapsule production method, It is possible to produce a reclaimable microcapsule in which a metal catalyst having excellent reusability and recyclability is incorporated without leakage to the outside.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating the structure of a microfluidic device according to the present invention; FIG.
FIG. 2 is a result of observing the manufacturing process of the double droplet according to the first embodiment of the present invention using an optical microscope.
FIG. 3 (a) is a result of observing the shape of the microcapsules dispersed in water according to Example 1 of the present invention using an optical microscope, and FIG. 3 (b) The result of observing the membrane section of the capsule using a scanning electron microscope.
4 is a graph showing the size of microcapsules according to Example 1 of the present invention measured using a particle size analyzer.
5 (a) is a graph showing the results of microcapsule permeation of fluorescent particles using a confocal fluorescence microscope after dispersing the microcapsules according to Example 1 of the present invention in a fluorescent luminescent compound mixture containing sulfolodamine-B for 24 hours FIG. 5 (b) is a graph showing the results obtained when the microcapsules according to Example 1 of the present invention were mixed with a fluorescent luminescent compound mixture solution containing (FITC-tagged) fluorescent latex beads labeled with fluorescein isothiocyanate After dispersing with time, it was observed whether or not the fluorescent particles were permeable to microcapsules using a confocal fluorescence microscope.
6 (a) is a result of observing the shape and size of platinum catalyst particles according to Comparative Example 1 of the present invention using a transmission electron microscope, and Fig. 6 (b) The shape and size of the platinum catalyst particles contained in the capsule were observed using a transmission electron microscope.
7 is a graph showing the size of platinum catalyst nanocolloidal particles stabilized with polyvinylpyrrolidone present in the inner droplet of the microcapsule according to Example 1 of the present invention using a particle size analyzer.
FIG. 8 is a result of observing the degree of restoration of microcapsules according to rehydration time of microcapsules dried according to Experiment (7) of Example 1 of the present invention through an optical microscope.
9 shows the results of evaluating the catalytic activity according to the sizes of the microcapsules prepared according to Examples 1 to 3 through the method of Experiment (8) of the present invention.
10 is a graph showing the results of 10 repeated measurements of the catalytic activity of the microcapsules according to Example 1 through the method of Experiment (8) of the present invention.
The present invention relates to a method of producing a reclaimable microcapsule containing a metal catalyst, comprising the steps of: (a) preparing an aqueous dispersion solution comprising metal catalyst nanocolloid particles and a polymer type surfactant; (b) an outer tube which is open on both sides, an intermediate tube which is present in one side of the outer tube, an inner tube which is present inside the intermediate tube, and an inner tube which is present on the other side of the outer tube, Wherein the intermediate tube and the inner tube have a shape of a nozzle whose inner diameter is decreased according to the flow direction of the fluid, wherein the flow of the aqueous dispersion solution into the inner tube and the flow of the water The flow of the oil containing the higher alcohol and the photopolymerizable monomer in the same direction as the flow of the dispersion solution and the flow of the continuous phase containing the polymer type surfactant in the direction opposite to the flow of the aqueous dispersion solution as the outer tube are introduced, Forming a double droplet of size; And (c) photopolymerizing the double droplet to produce a microcapsule in which the metal catalyst in the form of a fine particle is embedded.
More specifically, in the present invention, the step (a) of preparing an aqueous dispersion solution containing metal catalyst nanocolloid particles and a polymer type surfactant comprises the steps of (1) mixing a metal ion complex with a polymer type surfactant and a volatile lower alcohol solvent Mixing to prepare a suspension; (2) applying microwave to the suspension and evaporating the volatile lower alcohol solvent to obtain stabilized metal catalyst nanoparticles; And (3) re-dispersing the metal catalyst nanoparticles in an aqueous solution containing a polymer type surfactant to prepare an aqueous dispersion solution containing the metal catalyst nanocolloid particles.
In the present invention, the polymer type surfactant used in steps (1) and (3) of (a) preparing an aqueous dispersion solution containing metal catalyst nanocolloid particles and a polymer type surfactant is polyvinyl alcohol Polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), and the like.
In the step (1) of the present invention, the polymer type surfactant is added for stabilization of the metal ion complex having a high reactivity, and polyvinyl pyrrolidone (PVP) may be preferably used, but the present invention is not limited thereto. In the step (1), the polymer type surfactant may be added in an amount of 0.001 mg to 1 mg per 4.0 mg of the metal ion complex and 0.5 to 2 mg per 1 mL of the volatile lower alcohol solvent. However, the content of the polymer type surfactant is not limited to metal And is not particularly limited as long as it can stabilize the ion complex.
In addition, the volatile lower alcohol solvent used in the step (1) of the present invention may be prepared by uniformly dispersing a metal ion complex and a polymer type surfactant, generating a reduction reaction of the metal ion complex through oxidation of the volatile lower alcohol solvent, Is used to prepare catalyst nanoparticles. The volatile lower alcohol solvent may be any one selected from the group consisting of volatile lower carbon alcohols having a carbon number of C 1 to C 5 , more preferably one or more selected from the group consisting of methanol and ethanol But is not limited thereto.
In the present invention, the metal ion complex of the step (1) may be a compound containing a metal ion which can be used as a catalyst, preferably silver, gold, titanium, zirconium, vanadium, niobium, tantalum, chromium, molybdenum, And at least one metal ion selected from the group consisting of tungsten, iron, rubidium, osmium, nickel, rhodium, palladium, iridium and platinum. Thereafter, microwave is applied to the suspension (2), and then the volatile lower alcohol solvent is evaporated to obtain stabilized metal catalyst nanoparticles. By microwave irradiation to the suspension through the step, the lower alcohol solvent The reduction reaction of the metal ion complex is generated by the oxidation reaction of the metal catalyst nanoparticles. Thus, the stabilized metal catalyst nanoparticles can be prepared and the suspension having the metal catalyst nanoparticles uniformly distributed can be produced. The metal catalyst nanoparticles can be obtained by evaporating the volatile lower alcohol solvent of the suspension in which the metal catalyst nanoparticles are uniformly distributed.
Dispersing the metal catalyst nanoparticles (3) of the present invention in an aqueous solution containing a polymer type surfactant to prepare an aqueous dispersion solution containing metal catalyst nanocolloid particles, wherein the aqueous dispersion solution is prepared from the present invention And the polymer type surfactant may be included for the stabilization of the aqueous dispersion solution used as the internal droplet.
In the present invention, the polymer type surfactant in the step (3) may be contained in an amount of 5 to 20% by weight, preferably 8 to 15% by weight, more preferably 9 to 11% by weight based on the total weight of the aqueous dispersion solution, The content of the polymer type surfactant is not particularly limited as long as it can stabilize the aqueous dispersion solution and the metal catalyst particles contained in the aqueous dispersion solution.
In the present invention, the metal catalyst nanocolloidal particles of the step (3) may have a size of 1 to 1000 nm and may include 1 to 40% by volume based on the total volume of the aqueous dispersion solution. Since the metal catalyst nanocolloidal particles should be smaller than the size of the microcapsules, the size is preferably 1000 nm or less, but is not particularly limited as long as it can be incorporated into microcapsules.
The microfluidic device used in step (b) of the present invention comprises an inner tube, a middle tube, a collecting tube, and an outer tube as shown in FIG. 1, and the inner diameter increases in order. The outer tube has an open shape in which both tubes are open. Inside one of the outer tubes, there is an intermediate tube in which an inner tube exists, and a collection tube existing opposite to the middle tube exists in the other inner side of the outer tube do. In this case, since each tube is connected to the external fluid supply device in a separated state, the fluid can be introduced without being mixed with each other, and the intermediate tube and the inner tube are formed into a nozzle shape in which the inner diameter decreases according to the flow direction of the fluid And the end of the inner tube has a shape of about 0.1 to 1 mm from the end of the middle tube into the middle tube. The collection tube may have a nozzle shape in which the inner diameter decreases according to the fluid flow opposite side, wherein the inner diameter of the collection tube may be the same or larger than the inner diameter of the middle tube.
Higher alcohol in the step (b) of the present invention can be included in the intermediate tube oil and which have one or more selected from the group consisting of number of C 8 or more carbon alcohol, preferably consisting of C 10 to C 12 alcohol, May be used, but the present invention is not limited thereto. Polymer capsules can be prepared by introducing a photopolymerizable monomer solution into the oil of the intermediate tube containing the volatile higher alcohol.
In the step (b) of the present invention, the photopolymerizable monomer contained in the oil of the intermediate tube together with the higher alcohol may be at least one functional group selected from the group consisting of an acrylate group, a cyanoacrylate group, an allyl group and an epoxy group Is contained in one molecule, and specific examples thereof include triethyleneglycol diacrylate, 1,4-butanediol diacrylate, 1,6- But are not limited to, 1,6-hexanediol diacrylate, neopentylglycol diacrylate, pentaerythritol acrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, Acrylate, pentaerythritol triacrylate, dipentaerythritol diacrylate, dipentaerythritol triacrylate, But are not limited to, dipentaerythritol triacrylate, dipentaerythritol pentacrylate, pentaerythritol hexacrylate, bis-phenol A diacrylate, Novolakepoxyacrylate ), Ethylene glycol dimethacrylate, diethyleneglycol dimethacrylate, triethyleneglycol dimethacrylate, propyleneglycol dimethacrylate, 1, 1,4-butanediol dimethacrylate and 1,6-hexanediol dimethacrylate, and more preferably trimethylolpropane triacrylate, 1,6-hexanediol dimethacrylate, (Trimethylolpropane triacrylate, TMPTA) can be used. However, the present invention is not limited thereto, and any polymeric monomer which can be cured by ultraviolet rays can be used without limitation.
In the present invention, the oil of the intermediate tube of the step (b) may further contain a photoinitiator and a fluorescent dye. The photopolymerizable monomer contained in the oil of the intermediate tube is allowed to be photopolymerized through the photoinitiator. Although the fluorescent dye has no significant difference in function, the fluorescent dye can be used for the production of double droplets and microcapsules having fluorescence, And the like can be given.
In the step (b) of the present invention, the continuous phase flowing in the outer tube may contain 5 to 20% by weight, preferably 8 to 15% by weight, more preferably 9 to 11% by weight, based on the total weight of the continuous phase, However, the content of the above-mentioned polymer type surfactant is not particularly limited as long as it can stabilize the oil droplet of the intermediate tube. At this time, the polymer type surfactant contained in the continuous phase may be any one or more selected from the group consisting of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP), and more preferably polyvinyl alcohol PVA) may be used, but any material that can stabilize the oil droplet can be used. Also, when the aqueous dispersion solution of the present invention and the polymer surfactant contained in the continuous phase have the above-mentioned content range, the polymer surfactant is positioned at the interface with the higher alcohol contained in the oil droplet to effectively reduce the interfacial energy In addition, the flexibility of the film can be improved by effectively binding to the interface of the polymer formed by photopolymerization. Accordingly, when the capsule membrane of the microcapsule is stored for a long time and rehydrated by a solvent such as water in a dried state, the original shape It is possible to exhibit excellent restorability by being restored. Preferably, since the capsule membrane has a porous structure, when the capsule membrane is rehydrated, the capsule membrane is restored within a short period of time as the solvent penetrates uniformly into the inside and the outside of the membrane, thereby exhibiting excellent restorability.
The solvent used in the rehydration may be water, an aliphatic hydrocarbon solvent, an alicyclic hydrocarbon solvent, an aromatic hydrocarbon solvent, an alcohol solvent, a ketone solvent, an ether solvent, an ester solvent, a nitrile solvent and an acetate solvent And the like, and any solvent capable of performing a chemical reaction without affecting the structure of the capsule membrane can be used without limitation.
In the method of manufacturing the reclaimable microcapsule containing the metal catalyst of the present invention, in the process of preparing the double droplet through the step (b), by controlling the flow rate of the aqueous dispersion solution, the oil flow and the continuous phase flow, The size and the thickness of the substrate can be controlled. The size of the double droplet to be manufactured and the thickness of the oil film including the internal droplet are determined by the size of the microtubule and the flow of the aqueous dispersion solution existing in the inner tube of the microfluidic device, Depending on the flow rate of the phase flow, any flow rate can be used provided that it stably forms the desired double droplet. Typically flow rates in the range of 60 to 6000 microliters (μl) per hour can be used. The size of the droplet formed can be controlled mainly by the flow rate of the continuous phase flow through the outer tube, and the lower the flow velocity of the continuous phase flow, the larger the droplet can be formed. In addition, the larger the flow velocity of the internal droplet forming flow, the larger the droplet can be formed. By controlling the flow of fluids, it is possible to form a uniform double droplet, so that a thin microcapsule can be manufactured. By maintaining the flow rates of the aqueous dispersion solution stream, the oil stream and the continuous phase stream, it is possible to produce a double droplet formed of an oil film of uniform size and uniform thickness through which a capsule membrane of uniform size and uniform thickness The preparation of microcapsules may be possible.
The particle size of the microcapsule prepared from the method of manufacturing the microcapsule in which the metal catalyst is embedded according to the present invention may be from 1 to 1000 탆. If a larger size microcapsule is required, Microcapsules having particle size can be prepared, but are not limited thereto.
In the step (c) of the present invention, photopolymerization of the double droplet to produce a microcapsule in which the metal catalyst in the form of a fine particle is incorporated, the photopolymerization is carried out by irradiating the double droplet prepared in the step (b) at a dose of 1000 to 10,000 mW / Preferably 0.5 to 5 seconds, preferably 1 to 3 seconds, in an ultraviolet ray region having a light intensity of 5000 mW / cm < 2 >.
In the method of preparing the reclaimable microcapsule containing the metal catalyst of the present invention, the porous polymer membrane is formed by phase separation of the polymerized polymer and the higher alcohol in the photopolymerization process of the step (c). By exposing the double droplet prepared in the step (b) to the ultraviolet ray region, the polymerization reaction of the photopolymerizable monomer contained in the oil droplet of the double droplet occurs, and the polymerized polymer according to the polymerization reaction of the monomer on the oil film Phase separation of higher alcohol occurs, so that the restorative microcapsule having the porous polymer capsule membrane naturally can be produced without further process. The microcapsule having the porous polymer capsule membrane may have a selective permeability depending on the pore size. Further, there is no need to remove or sinter the porous membrane to form a porous structure, and the activity of the metal catalyst existing in the membrane Can be remarkably improved to the level equivalent to the activity of the homogeneous catalyst, and can be directly used as a catalyst in a specific chemical reaction. In addition, the microcapsules are dried after being stored for a long time after being manufactured, so that even when the shape of the conventional capsule is deformed, the activity of the metal catalyst nanoparticles stored therein is maintained, and the microcapsules are immersed in water, It can be restored to an existing shape, and the restoration property, reusability and recyclability can be remarkably improved.
The present invention relates to a microcapsule prepared from a method for producing a reclaimable microcapsule in which the metal catalyst is impregnated, wherein the microcapsule contains metal catalyst nanocolloid particles therein and has a porous polymer membrane form.
The present invention also relates to a method for hydrogenating an organic compound using the reclaimable microcapsule containing the metal catalyst as a catalyst. The restorative microcapsule prepared from the process for preparing the reclaimable microcapsule containing the metal catalyst of the present invention can be used as a catalyst in a specific chemical reaction due to the reactivity of the metal catalyst stored therein, Can be used as a catalyst in the chemical reaction to be added.
Hereinafter, preferred embodiments of the present invention will be described in order to facilitate understanding of the present invention. However, it should be understood that the present invention is not limited to the described embodiments, but various modifications and alterations may be made therein without departing from the spirit and scope of the invention.
[Manufacturing Example] Preparation of microfluidic device
As a middle tube, a cylindrical capillary tube having a diameter of 113 탆 and having a hydrophobic coating with n-octadecyltrimethoxysilane (Sigma Aldrich, USA) was used. Has an inner diameter of 164 占 퐉 and has a narrow width shape with hydrophilic coating using 2-methoxy ([polyethylenoxy] propyl) trimethoxysilane (Gelest, Inc., USA) Were used. A square capillary (OD (Outer diameter): 1.5 mm, an ID (Inner diameter): 1.05 mm) was used as the outer tube, and the middle tube and the collecting tube were introduced at both ends of the square capillary tube, Lt; / RTI > Thereafter, a cylindrical capillary having an inner diameter of 113 탆 and a hydrophilic nature and a narrowed width of one side was introduced as an inner tube into the middle tube to prepare a microfluidic device.
[Example 1] Preparation of microcapsules having a size of 106 mu m
Preparation of aqueous dispersion solution containing platinum (Pt) catalyst nanocolloid particles
4.0 mg of potassium chloroplatinate (K 2 PtCl 4 , Potassium tetrachloroplatinate (II)) as a metal ion complex was added to 10 ml of an ethanol solvent containing 10 mg of polyvinylpyrrolidone having a weight average molecular weight of 10,000 as a stabilizer To prepare a suspension containing the platinum ion complex. The solution was heated in a microwave oven of 1000 W for 10 seconds to generate a reduction reaction of the platinum ion complex by oxidation of the ethanol solvent, thereby preparing a suspension in which the stabilized platinum catalyst nanoparticles were uniformly distributed. Thereafter, the ethanol solvent of the suspension was evaporated at room temperature to obtain platinum catalyst nanoparticles. The obtained platinum catalyst nanoparticles were dissolved in a polyvinyl alcohol (PVA) aqueous solution containing 10 wt% of polyvinyl alcohol (PVA) And dispersed to prepare an aqueous dispersion solution containing platinum (Pt) catalyst nanocolloidal particles.
Preparation of Oil Containing Photopolymerizable Monomers (TMPTA Mixed Liquid)
1-dodecanol was dissolved in trimethylolpropane triacrylate (TMPTA, Sigma Aldrich, USA) in an amount of 15% by weight based on the total weight of the oil and Darocure 1173 (1-phenyl-2-hydroxy-2 -methyl propane-1-one (Sigma Aldrich, USA) in an amount of 0.5% by weight based on the total weight of the oil and 0.001% by weight of Nile red as a fluorescent dye based on the total weight of the oil, Gt; TMPTA < / RTI >
Manufacture of microcapsules
An aqueous dispersion solution containing the platinum catalyst nanocolloidal particles was introduced into the inner tube of the microfluidic device, and the TMPTA mixture was introduced into the middle tube of the microfluidic device. Further, a surfactant aqueous solution containing 10% by weight of polyvinyl alcohol (PVA) was introduced into the outer tube of the microfluidic device, and at this time, the flow direction of the surfactant aqueous solution was introduced so as to be opposite to the flow direction of the aqueous dispersion solution and the TMPTA mixed solution Respectively. At this time, 600 μl / h of the aqueous dispersion solution of the inner tube, 1000 μl / h of the TMPTA mixture solution of the middle tube, and the aqueous solution of the surfactant of the outer tube were introduced at a flow rate of 3500 μl / h, A double droplet with a nanocolloidal dispersion droplet was prepared and the prepared double droplet was collected using a collection tube. At this time, an experiment for observing the manufacturing process of the double droplet of the following experiment (1) was conducted using an optical microscope. Then, the collected double droplets were exposed to an ultraviolet region of 5000 mW /
[Example 2] Preparation of microcapsules having a size of 208 mu m
In the process of preparing the microcapsule of Example 1, 1200 μl / h of the water-dispersed solution of the inner tube, 1100 μl / h of the TMPTA mixture of the middle tube, and the aqueous solution of the surfactant of the outer tube were introduced at a flow rate of 3500 μl / h The microcapsules containing the platinum catalyst were prepared by the same procedure except that the microcapsules having a size of 208 mu m were prepared.
[Example 3] Preparation of microcapsules having a size of 310 mu m
In the preparation of the microcapsule of Example 1, 1500 μl / h of the water-dispersed solution of the inner tube, 1000 μl / h of the TMPTA mixture of the middle tube, and the surfactant aqueous solution of the outer tube were introduced at a flow rate of 3500 μl / h Microcapsules containing platinum catalyst were prepared by the same procedure except that microcapsules having a size of 310 mu m were produced.
[Comparative Example 1] Platinum (Pt) catalyst nanocolloidal particles
The aqueous dispersion solution containing the platinum (Pt) catalyst nanocolloidal particles of Example 1 was used as it was without going through the process of microcapsule production.
[Comparative Example 2] Preparation of microcapsules containing an aqueous dispersion solution and a general surfactant in a continuous phase
The platinum catalyst nanoparticles obtained in the preparation of the aqueous dispersion solution of Example 1 were dispersed in a surfactant aqueous solution containing 10% by weight of sorbitan monooleate to prepare platinum (Pt) catalyst nanocolloid particles The aqueous dispersion solution is introduced into the inner tube of the microfluidic device during the production of the microcapsule, and a surfactant aqueous solution containing 10 wt% of sorbitan monooleate is added to the microfluidic device The microcapsules containing the platinum catalyst were prepared by the same procedure except that the catalyst was introduced into the outer tube of the catalyst.
[Comparative Example 3] Production of microcapsules using oil droplets containing no higher alcohol
Microcapsules containing a platinum catalyst were prepared by the same procedure except that 1-dodecanol used as a higher alcohol was not included in the preparation of the oil (TMPTA mixture solution) containing the photopolymerizable monomer of Example 1 .
The microdroplets prepared in Examples 1 to 3, the platinum catalyst-containing microcapsules prepared in Examples 1 to 3, the platinum catalyst nanocolloid particles in Comparative Example 1, and the Comparative Examples 2 to 7 3 microcapsules. The results obtained from Experimental Examples 1 to 8 are shown in FIG. 2 to FIG. 10 and Table 1 below.
[Experimental Example 1] Observation of the manufacturing process of the double droplet
The process of preparing the double droplet was observed using an optical microscope.
[Experimental Example 2] Microcapsule type and microcapsule membrane cross section observation
The shape of the microcapsules dispersed in water and the film cross section of the microcapsules were observed using an optical microscope and a scanning electron microscope (SEM).
[Experimental Example 3] Measurement of microcapsule size
The size of the prepared microcapsules was measured using a particle size analyzer (ELSZ-1000, Otsuka Electronics Co., Lte., Japan).
[Experimental Example 4] Pore size prediction using selective permeability of microcapsules
The pore size of the prepared microcapsules was measured using two mixed solutions having different particle sizes. A fluorescent luminescent compound mixture solution containing fluorescence isothiocyanate (FITC-tagged) fluorescent latex beads labeled with Fluorescein isothiocyanate (Polyscience, Inc., USA) having a particle diameter of 100 nm at a concentration of 10 占 퐂 / (Sigma Aldrich, USA) at a concentration of 10 / / ml was prepared, and the microcapsules were dispersed in the mixture for 24 hours, respectively. After 24 hours, the microcapsule permeability of the fluorescent particles in the mixed solution was observed using a confocal fluorescence microscope (ECLIPSE Ti, Nikon, Japan), and the pore size was predicted through the observation.
[Experimental Example 5] Measurement of the shape and size of platinum catalyst particles and the size of stabilized platinum catalyst nanocolloidal particles
The shape and size of the platinum catalyst particles present in the microcapsules were observed using a transmission electron microscope (TEM, Tecnai G2 F30, FEI, USA) The size of the platinum catalyst nano-colloidal particles stabilized with polyvinylpyrrolidone (PVP) was measured using a particle size analyzer (ELSZ-1000, Otsuka Electronics Co., Lte., Japan).
[Experimental Example 6] Elemental content analysis of microcapsules
The content of the elements of the microcapsules was analyzed using an energy dispersive X-ray spectroscopy (EDX, LYRA3 XMU, LASDAM, Romania).
[Experimental Example 7] Observation of restorability of microcapsules
The microcapsules prepared in Example 1 and Comparative Examples 2 to 3 were stored at room temperature for 30 days and dried. Then, the dried microcapsules were added to water and rehydrated to obtain microcapsules Were observed through an optical microscope.
[Experimental Example 8] Evaluation of catalytic activity of microcapsules
Microcapsules containing the prepared platinum catalyst were added to a mixture of 0.07 mM of 4-nitrophenol and 7 mM of sodium borohydride (NaBH 4 ) in water, and the mixture was stirred for 1 hour. The conversion (%) of 4-nitrophenol to 4-aminophenol by hydrogenation of platinum catalyst was measured for 60 minutes using a UV-vis spectrometer at intervals of 5 minutes in the course of stirring. The catalytic activity of the platinum catalyst present in the droplets of the microcapsules was evaluated through the conversion rate (%) according to the measured reaction time.
FIG. 2 shows a result of observation of a process of manufacturing a double droplet using a microfluidic device by an optical microscope. In detail, it can be confirmed that a double droplet is manufactured from an intermediate tube including an inner tube existing inside the left side of the outer tube and a double droplet made from a collection tube existing inside the right side of the outer tube is collected. It was confirmed that the droplet size was very uniform.
FIG. 3 shows the results of observing the shape of the microcapsules dispersed in water and the film surface of the microcapsules using an optical microscope and a scanning electron microscope (SEM). In detail, FIG. 3 (a) is a result of observing the shape of the microcapsules prepared in the examples dispersed in water with an optical microscope, and FIG. 3 (b) Observation results. Through the results (a) and (b) of FIG. 3, microcapsules washed with isopropyl alcohol, ethanol and water after the preparation were not influenced by the three solutions and maintained the original shape . Through this, it was confirmed that photopolymerization of TMPTA (trimethylolpropane triacrylate), which forms a capsule membrane through polymerization in the microfluidic device, has successfully occurred and a stable capsule film is formed.
FIG. 4 shows the results of size distribution of the microcapsules prepared in Example 1 using a particle size analyzer (ELSZ-1000, Otsuka Electronics Co., Lte., Japan). 4, the size of the microcapsules prepared by the method of Example 1 was 106 μm and the coefficient of variance (CV) was narrower than 1.6%. The microcapsules of Examples 2 and 3 were also measured in the same manner as the microcapsule size measuring method of Example 1. The microcapsules of Example 2 had a size of 208 μm (coefficient of variation: 1.4% , And the size of the microcapsule of Example 3 was 310 탆 (coefficient of variation: less than 1.7%). As a result of the narrow size distribution, it is possible to maintain a stable state of the double droplets existing in the continuous phase by the polymerization reaction proceeding at room temperature. Thus, by using a simple method using a microfluidic device, It was confirmed that the capsule could be manufactured.
FIG. 5 shows the result of observing whether a microcapsule membrane of a fluorescent material permeates to estimate the pore size of the microcapsule by the method of Experimental Example 4. FIG. More specifically, FIG. 5 (a) shows that the microcapsules of Example 1 were dispersed for 24 hours in a fluorescent luminescent compound mixture prepared by mixing sulfolodamine-B having a particle diameter of 2 nm at a concentration of 10 占 퐂 / ml for 24 hours, FIG. 5 (b) shows the result of observing the fluorescence particle permeability of the fluorescent particles using a microscope, and FIG. 5 (b) shows the results of observing the FITC-tagged fluorescent latex beads labeled with fluorescein isothiocyanate having a particle diameter of 100 nm Mu] g / ml, the microcapsules of Example 1 were dispersed for 24 hours, and then the microcapsule membrane permeability of the fluorescent particles was observed using a confocal fluorescence microscope. The result of FIG. 5 (a) shows that sulfolodamine-B having a particle diameter of 2 nm penetrates into microcapsules through pores existing in the microcapsule membrane, and both the inside and the outside of the microcapsule membrane fluoresce . 5 (b), the fluorescent latex beads having a particle diameter of 100 nm did not pass through the pores of the microcapsule membrane and were not penetrated into the microcapsule, but existed only in the mixed solution of the fluorescent light-emitting compound, Fluorescence. From these results, it can be seen that the diameter of pores of the microcapsules prepared according to the present invention is larger than 2 nm and less than 100 nm, and that the microcapsules have selective permeability depending on the particle size there was.
FIG. 6 shows the result of observing the shape and size of platinum catalyst particles according to encapsulation using a transmission electron microscope (TEM). 6 (a) shows the result of observation of the shape and size of the non-encapsulated platinum catalyst particles of Comparative Example 1. Fig. 6 (b) shows the results of observation of the shape and size of the platinum catalyst particles embedded in the microcapsules of Example 1. Fig. Shape and size. 6 (a) and 6 (b), it was confirmed that there was no change in the shape of the platinum catalyst particle. The size of the platinum catalyst particle of Comparative Example 1 measured was (1.59 ± 0.33 nm) , And the size of the platinum catalyst particle of Example 1 was (1.65 ± 0.25 nm). As a result, it was confirmed that the size and shape of the platinum catalyst did not change during the encapsulation process.
FIG. 7 shows the results of measurement of the size of platinum catalyst nanocolloidal particles stabilized with polyvinylpyrrolidone (PVP) contained in the microcapsule internal droplet through the present invention using a particle size analyzer. 7, it can be seen that the average size of the platinum catalyst nanocolloidal particles stabilized with polyvinylpyrrolidone (PVP) present in the microcapsule inner droplet is the average size of the original PVP stabilized platinum catalyst nano-colloid particles not encapsulated And it was confirmed that the side reaction of the platinum catalyst nanocolloidal particles did not occur during the encapsulation process of the platinum catalyst nanocolloidal particles using the microfluidic device or the photopolymerization process due to the exposure to ultraviolet rays there was. The average size of the PVP-stabilized platinum catalyst nano-colloid particles was larger than that of the microcapsule pores of the present invention having a diameter of 2 to 100 nm as shown in FIG. 5, It was confirmed that when the microcapsule is immersed in the microcapsule, leakage to the outside is impossible and stable storage is possible.
The results of analyzing the content of the elements of a part of the microcapsules prepared by the method of Example 1 using the energy dispersive X-ray spectroscope (EDX) are shown in the following Table 1 .
From the results of Table 1, it was confirmed that 1.42 wt% of platinum was contained in the microcapsules analyzed, and it was found that the platinum catalyst nanocolloid particles were stably incorporated into the microcapsules.
FIG. 8 shows the result of microscopic observation of the degree of restoration of the microcapsules prepared in Example 1 of the present invention in the dried state according to rehydration time. The results of FIG. 8 indicate that the microcapsules which were dried at room temperature for a long period of time and then changed in morphology were restored with time in water. It was confirmed that the capsules were gradually returned to their original shape with the lapse of time after the addition of the dry microcapsules to water. At about 750 seconds after the drying, the microcapsules, which were dried and changed shape, were completely restored . However, in the case of the microcapsules of Comparative Examples 2 to 3, the dried microcapsules were dried at 750 seconds after the addition of the dried microcapsules, and the modified microcapsules were not completely restored to their original microcapsule form The results are shown.
FIG. 9 shows the results of evaluating the catalytic activity of microcapsules prepared from Examples 1 to 3 according to the size of microcapsules by measuring the catalytic activity by the method of Experimental Example 8. FIG. As shown in FIG. 9, it was found that the time required to reach the chemical reaction equilibrium due to the catalytic reaction inside the microcapsules became longer as the size of the capsule increased. However, since the conversion (%) of conversion of 4-nitrophenol to 4-aminophenol by the hydrogenation reaction of the platinum catalyst achieves 98% or more, which is equivalent to the conversion rate indicated by the homogeneous catalyst within 60 minutes, It was confirmed that the activity of the platinum catalyst existing in the microcapsules of Examples 1 to 3 was well maintained.
10 shows the results of evaluating the catalytic activity of the microcapsules prepared in Example 1 in which the method of Experimental Example 8 was repeated 10 times. 10, in which the final conversion (%) of 4-nitrophenol by the hydrogenation reaction of the platinum catalyst was 93% or more, the activity of the catalyst contained in the microcapsule prepared through the present invention And can be used repeatedly as a catalyst in many chemical experiments without leaking platinum catalyst nanocolloidal particles to the outside of the microcapsules, so that reusability and recyclability are very high.
2 to 10 and Table 1 which are the results of Experimental Examples 1 to 8 show that the metal catalyst having a high catalytic activity can be easily removed by microcapsules It is possible to produce microcapsules of uniform size which can be stably stored without leakage to the outside. In addition, the microcapsule manufacturing method of the present invention can be applied not only to the selective permeation through the pores existing in the capsule membrane of the microcapsule, but also to the microcapsule which can be used as a catalyst having a catalytic activity as high as the homogeneous catalyst ≪ / RTI > In addition, it is possible to prepare a microcapsule having excellent restorability that can be restored to its original form in a short time by rehydrating it by adding it to a solvent even after drying through the above-mentioned microcapsule manufacturing method, Indicating that it is possible to produce microcapsules excellent in reusability and recyclability as a catalyst.
Claims (12)
(b) an outer tube which is open on both sides, an intermediate tube which is present in one side of the outer tube, an inner tube which is present inside the intermediate tube, and an inner tube which is present on the other side of the outer tube, Wherein the intermediate tube and the inner tube have a shape of a nozzle whose inner diameter is decreased according to the flow direction of the fluid, wherein the flow of the aqueous dispersion solution into the inner tube and the flow of the water The flow of the oil containing the higher alcohol and the photopolymerizable monomer in the same direction as the flow of the dispersion solution and the flow of the continuous phase containing the polymer type surfactant in the direction opposite to the flow of the aqueous dispersion solution as the outer tube are introduced, Forming a double droplet of size; And
(c) photopolymerizing the double droplet to prepare a microcapsule containing a metal catalyst in the form of a fine particle.
(A) mixing (1) a metal ion complex with a polymer type surfactant and a volatile lower alcohol solvent to prepare a suspension;
(2) applying microwave to the suspension and evaporating the volatile lower alcohol solvent to obtain stabilized metal catalyst nanoparticles;
(3) re-dispersing the metal catalyst nanoparticles in an aqueous solution containing a polymer type surfactant to prepare an aqueous dispersion solution containing the metal catalyst nanocolloid particles; and Gt;
Wherein the polymer type surfactant in step (a) is a metal catalyst containing at least one selected from the group consisting of polyvinyl alcohol and polyvinyl pyrrolidone.
The metal ion complex of the step (1) is selected from the group consisting of silver, gold, titanium, zirconium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, iron, rubidium, osmium, nickel, rhodium, palladium, iridium and platinum Wherein the metal catalyst contains at least one metal ion.
Wherein the polymer type surfactant in the step (3) is contained in an amount of 5 to 20 wt% based on the total weight of the aqueous dispersion solution.
Wherein the metal catalyst nanocolloidal particles have a size of 1 to 1000 nm and are contained in an amount of 1 to 40% by volume based on the total volume of the aqueous dispersion solution.
Wherein the photopolymerizable monomer comprises at least two functional groups selected from the group consisting of an acrylate group, a cyanoacrylate group, an allyl group and an epoxy group in one molecule. A method for producing microcapsules.
Wherein the continuous phase comprises a polymeric surfactant in an amount of 5 to 20 wt% based on the total weight of the continuous phase.
Wherein the size and the thickness of the polymer microcapsule are controlled by controlling the flow rate of the aqueous dispersion solution, the oil flow, and the continuous phase flow.
Wherein the porous polymer membrane is formed by phase separation of the polymerized polymer and the higher alcohol in the photopolymerization step of the step (c).
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| KR20150010607A (en) | 2013-07-19 | 2015-01-28 | 주식회사 엘지화학 | Supported-catalyst, method for preparing thereof, and secondary structures of carbon nanostructures prepared by using same |
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| KR20150010607A (en) | 2013-07-19 | 2015-01-28 | 주식회사 엘지화학 | Supported-catalyst, method for preparing thereof, and secondary structures of carbon nanostructures prepared by using same |
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