KR20130033556A - Fixed-bed microreactor and manufacture method thereof - Google Patents

Abstract

The present invention relates to a fixed bed microreactor in which metal nanoparticles are regularly fixed at selected positions of a self-assembled inorganic mesopore, and a method of manufacturing the same. A micro reactor capable of discharging a fluid, comprising a thin film having metal nanoparticles fixed to nanopores and a microchannel arranged on the thin film, wherein the thin film is fixed to a lower surface of the microchannel. Prepare.
By using the fixed-bed microreactor as described above and a method of manufacturing the same, metal NPs having a desired size in functionalized pores can be immobilized to withstand various chemical reaction conditions and prevent aggregation of NPs.

Description

Fixed-bed microreactor and manufacture method

The present invention relates to a fixed-bed microreactor and a method for manufacturing the same, and particularly, to a fixed-bed microcatalytic reactor in which metal nanoparticles are fixed at selected positions of a self-assembled inorganic mesopore. The manufacturing method is related.

In general, catalysts are substances that play a central role in many chemical reactions, and are divided into homogeneous catalysts and heterogeneous catalysts. Homogeneous catalysts are dissolved in a solvent to allow reactants to access the active site of the catalyst. Although preferred below, it has been limited to commercial use because it is difficult to separate from the final product. On the other hand, heterogeneous catalysts are more restricted than the homogeneous catalysts in accessing the active site of the catalyst, but supporting the catalyst on nanoparticles (NPs) increases the exposed area of the catalyst, which greatly enhances the contact between the reactant and the catalyst. do. Therefore, such a homogeneous catalyst not only acts as a homogeneous catalyst but also does not dissolve in a solvent, and thus can be easily separated from the reaction mixture, which is in the spotlight.

In the field of homogeneous catalysts in which nanoparticles (NPs) supported on solid surfaces such as silica or alumina are used, nanocatalysts have received great attention over the past decade. NPs have a high surface-to-volume ratio that provides a large active surface area. Thus, the catalyst efficiency per weight that can be used is higher than the bulk catalyst.

However, there were the following problems.

Difficulties exist in controlling particle size and interactions between particles and substrates, evaluating catalytic activity, and studying catalysis nontrivial.

In addition, the metal NPs tend to aggregate and sinter, which can drastically lower the catalyst efficiency. Thus, immobilization and synthesis of well-defined metal NPs using controllable shapes and sizes on nanostructured substrates is a key technique required to improve the activity and stability of heterogeneous NPs catalysts.

In recent years, due to its unique physicochemical properties and interesting catalytic performance, it has been found to have significant implications for immobilizing metal NPs on mesoporous sol-gel materials or polymers to catalyze many types of chemical reactions. There has been effort.

Despite significant advances in the field of NPs synthesis, the precise placement and immobilization of NPs at the appropriate site remains a major technical challenge. Typically, template synthesis is mainly used. Among the available self-assembled molds, thin films of nanoporous block copolymers have attracted much attention, which self-assembled into well-ordered nanostructures. Because of the great ability to be. Meso-phase separated block copolymer thin film features unique structural tenability, patterned irradiated NPs through self-assembled nano-domains, easy handling, and ready for other materials It offers distinct advantages such as low cost.

However, these studies have focused on organic-organic block copolymers and have used them as physical masks, which are removed by an etching step after the patterning process. These organic polymers are not suitable for use in applications that are exposed to harsh environments, which are environments that require solvent resistance and chemical and frictional properties.

Incorporating functional NPs into lab-on-a-chip (LOC) improves performance in chemical synthesis, biological sensing, medical diagnostics, and atmospheric analysis, it is also desirable to integrate metal NPs into microfluidic channels. In particular, fixed-bed microreactor applications that facilitate mass transfer of reactants with NP catalysts immobilized by the high surface-to-volume ratio of the microchannels are very useful.

In addition, the microfluidic reactor generally refers to a reactor composed of a channel having a width and a width of several hundred micrometers or less, and refers to a reactor capable of allowing the fluid to be mixed while passing through the microchannel and discharging the mixed fluid. Techniques for producing microfluidic reactors range from methods derived from electronics to micro-etching techniques to the latest ultra-precision process technologies. This variety of choices allowed the fabrication of various shapes such as three-dimensional structures. Materials used in the conventional reactors include silicon, glass, and polymer materials, including metals. In particular, silicon is mainly used in semiconductor processes using dry or wet etching.

An example of a technique related to such a microreactor is disclosed in Patent Documents 1 and 2 below.

That is, Patent Document 1 below comprises a fluid input part into which the fluid to be mixed is introduced, a fluid mixing part into which the injected fluid is mixed, and a fluid discharge part from which the mixed fluid is discharged. The base film, which is a thermoplastic polymer film having a fine hole communicating with the fluid input part, and the fluid discharge part, is laminated on the base film, and the cover film, which is a homogeneous or heterogeneous thermoplastic polymer film, is heated on the Tg melting point of the cover film. A microreactor that is integrally bonded by pressure is disclosed, and Patent Document 2 below discloses a solid substrate in a solution containing a polymer having a polyethyleneimine skeleton, followed by extraction, to form a polymer layer on the surface of the solid substrate. And a source of the metal substrate and the solid substrate having the polymer layer obtained in the step The contacts to precipitate the metal oxide in the polymer layer of the solid substrate surface, has been disclosed for an application method as a catalyst fixed reactor and a step of forming a nano-composite structure.

(Patent Document 1) Korean Unexamined Patent Publication No. 2011-0024992 (published March 9, 2011) (Patent Document 2) Korean Unexamined Patent Publication No. 2010-0051612 (published May 17, 2010)

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems described above, a method for synthesizing an organic-inorganic diblock copolymer having a disulfide linkage and a rule having a thiol functional group exposed from the diblock copolymer. The present invention provides a fixed bed microreactor equipped with a method for preparing a thin inorganic film of nano pores and a method of manufacturing the same.

Another object of the present invention is to immobilize metal NPs in functionalized pores and thus tolerate harsh reaction atmospheres, to prevent aggregation of NPs, to allow uniform dispersion of catalyst particles, and to catalyze reactions. It is to provide a fixed bed micro reactor capable of producing a catalyst system which provides a very large surface area-to-volume ratio and a process for the preparation thereof.

In order to achieve the above object, a process for preparing a fixed bed microreactor according to the present invention comprises (a) a self-assembled poly (vinylsilazane) -block-poly (ethylene oxide) diblock copolymer (PVSZ-SS-PEO). Synthesizing, (b) providing the thin film of PVSZ-SS-PEO of step (a) on a substrate, (c) reducing the thin film prepared in step (b) to clean the PEO block. Immersing in (d) obtaining a thiol-functionalized nanoporous thin film by (c), (e) selectively fixing metal nanoparticles to the nanopores, (f) and e) placing and clamping the microchannels on the film to which the metal nanoparticles are fixed by step e).

In the method of manufacturing a fixed bed microreactor according to the present invention, the PVSZ-SS-PEO in the step (a) is polyvinylsilazane (PVSZ) using a PEO-based macroinitiator containing a disulfide bond. It is characterized in that it is synthesized by reversible addition fragmentation chain transfer (RAFT) polymerisation.

In addition, in the method for manufacturing a fixed bed microreactor according to the present invention, the reducing agent is characterized in that the dithiothreitol (DTT) solution.

In the method of manufacturing a fixed bed microreactor according to the present invention, the metal nanoparticles are Au or Pd, Ag, and the metal nanoparticles are selectively immobilized due to the chemical affinity between the Au or Pd, Ag metals and thiol groups. It is characterized by.

In addition, in the method for manufacturing a fixed bed microreactor according to the present invention, the thin film is characterized in that it is located on the lower surface in the fluoropolymer microchannel produced by lithography.

In addition, the micro reactor according to the present invention to achieve the above object is a micro reactor that allows the fluid to be mixed while passing through the micro-channel, and discharge the mixed fluid, a thin film and the metal nanoparticles are fixed to the nanopores and And a microchannel disposed on the thin film, wherein the thin film is positioned on a lower surface of the microchannel.

In the micro-reactor according to the present invention, the metal nanoparticles are Au, Pd, Ag, and the metal nanoparticles are selectively immobilized.

In the micro-reactor according to the present invention, the microchannel is characterized in that the fluorine polymer.

As described above, according to the fixed bed microreactor according to the present invention and a method for manufacturing the same, the functionalized inorganic polymer pores can be immobilized with metal NPs having a desired size to withstand harsh reaction atmosphere, and the aggregation of NPs can be prevented. The effect that can be prevented is obtained.

In addition, according to the fixed bed microreactor according to the present invention and a method for producing the same, the effect of producing a catalyst system that allows uniform dispersion of catalyst particles and provides a very large surface area-to-volume ratio for the catalytic reaction. Obtained.

1 is a schematic diagram of a structure for preparing highly ordered metal NPs on self-assembled nanoporous thin film from PVSZ ₅₂ -SS-PEO ₁₁₃ diblock copolymer for heterogeneous catalysis in a fixed bed microfluidic system, FIG.
2 is a diagram showing a synthetic path of PVSZ ₅₂ -SS-PEO ₁₁₃ diblock copolymer having disulfide bonds,
3 shows a ¹ H-NMR spectrum according to the present invention,
4 is a view showing an image and a pattern of a thin film of the self-assembled PVSZ ₅₂ -SS-PEO ₁₁₃ block copolymer according to the present invention,
5 shows the FT-IR spectrum of the PVSZ ₅₂ -SS-PEO ₁₁₃ block copolymer,
6 shows immobilized on self-assembled nanoporous PVSZ film;
7 shows EDX spectra of Au and Pd NPs immobilized on self-assembled nanoporous thin films;
8 shows particle size distribution of Au and Pd NPs immobilized on self-assembled nanoporous thin film;
9 shows SEM, AFM and depth profiles of various self-assembled nanoporous thin films from PVSZ ₅₂ -SS-PEO ₁₁₃ diblock copolymers;
FIG. 10 is a TEM image for comparing Au NPs randomly immobilized on PVSZ-SH polymer films and Au NPs immobilized with excellent arrangement on self-assembled nanoporous polymers; FIG.
FIG. 11 is a view showing a manufacturing process of finely ordered metal nanoparticles immobilized on a self-assembling nanoporous thin film integrated in a microfluidic system having fluoropolymer microchannels for heterogeneous catalysis. FIG.
12 shows adhesion stability of Au NPs on a substrate of a block copolymer.

These and other objects and novel features of the present invention will become more apparent from the description of the present specification and the accompanying drawings.

First, the concept of the present invention will be described.

The present invention has developed a new and easy route for immobilizing nanoparticles on self-assembled inorganic thin film and used nanostructure embedded microreactor systems for heterogeneous catalysis. Solvent resistant fixed bed microreactors provide much better catalytic performance compared to conventional bulk processes and randomly deposited metal nanoparticle catalyst systems in glass flasks. The present invention proposes an alternative effective method for fabricating a lab-on-a-chip system that could lead to new applications in the field of microchemical and biological sensors.

EMBODIMENT OF THE INVENTION Hereinafter, the structure of this invention is demonstrated according to drawing.

1 shows the structure of preparing very regular metal NPs on self-assembled nanoporous thin film from PVSZ ₅₂ -SS-PEO ₁₁₃ diblock copolymers for heterogeneous catalytic reactions in fixed bed microfluidic systems. Is a schematic diagram.

1 is a schematic diagram for preparing a self-assembled block copolymer / NPs thin film fixed in microchannels for organic microchemical reaction applications.

In the present invention, an effective method of immobilizing metal NPs having a desired size in chemically induced position-selective functionalized inorganic mesopores has been used for heterogeneous catalysis in fixed bed microreactors. In the present invention, three organic reactions were tested in order to verify the functionality of the catalytic reactor.

Self-assembled poly (vinylsilazane) -block-poly (ethylene oxide) diblock copolymer thin film containing disulfide bond groups in a reducing agent such as dithiothreitol (DTT) solution to clean the PEO block By immersing the film (PVSZ-SS-PEO), a thiol-functionalized nanoporous thin film was obtained.

Subsequently, metal NPs were selectively immobilized at regular inorganic PVSZ nanopore positions because of the chemical affinity between thiol groups and Au or Pd metals. Self-assembled block copolymers / NPs thin film are positioned on the lower surface in fluoropolymer microchannels made by lithographic techniques.

Finally, a fixed-bed microfluidic system incorporating Au or Pd NPs nanostructures was used to conduct ethylene homo-coupling reactions, epoxidation of olefins and Heck reactions (heterogeneous catalytic microchemical reactions). See FIG. 1).

Next, metal nanoparticles immobilized at selected positions in the self-assembled inorganic mesoporous according to the present invention are described according to FIG. 2.

FIG. 2 is a diagram showing a synthesis path of PVSZ ₅₂ -SS-PEO ₁₁₃ diblock copolymer having disulfide bonds.

In the present invention, as shown in Figure 2, by inorganic polymerizing the reversible addition fragmentation chain transfer (RAFT) of polyvinylsilazane (PVSZ) using a PEO-based macroinitiator containing a disulfide bond -Organic diblock copolymers, ie PVSZ-SS-PEO, were synthesized.

An example of the synthesis of the self-assembled poly (vinylsilazane) -block-poly (ethylene oxide) diblock copolymer (PVSZ-SS-PEO), which is a main feature of the present invention, will be described in detail.

First, RAFT reagent synthesis will be described.

30 mmol of hydroxypropyl-mercatopyridine are dissolved in 30 mL DCM and 30 mmol of S-thiobenzoyl thioglycolic acid is added. To this solution, 30 mmol of DCC and 10 mmol of DMAP are added and stirred overnight at room temperature. After the reaction was completed, the solvent was evaporated and purified by column chromatography using a mixture of ethyl acetate / hexanes (2: 1 v / v ratio) to give RAFT reagent in red solution.

Next, the synthesis of the PEO macro initiator will be described.

Methoxylpolyethylene glycol 5000 (1 mmol) and PTSA (0.1 mmol) were added to the round bottom flask with toluene solvent. Then, 4 mmol of thioglycolic acid was slowly added to the solution, and the mixture was refluxed overnight under Ar atmosphere.

After cooling the reaction, the solvent was evaporated and the residue was partitioned using DCM / water and dried over MgSO ₄ . The organic layer was collected and concentrated at low pressure. To reduce the disulfide functional group, the compound was dissolved in MeOH, then 2 mmol of DTT was added and stirred for 3 hours at room temperature. The resulting solution was precipitated in diethyl ether to remove DTT and obtained as a pure white solid. 0.5 mmol of this product was then mixed with MeOH, 2.5 mmol of RAFT reagent and 0.5 mL of acetic acid as a solvent. This mixture was stirred for 6 hours at room temperature under Ar atmosphere. This reaction was stopped and the solvent evaporated. The product was purified by column chromatography using a mixture of ethyl acetate / hexanes (2: 1 v / v ratio) as eluent to give a pure red solid product.

Next, the synthesis of the PVSZ-SS-PEO diblock copolymer will be described.

A mixture of PEO-RAFT macroinitiator (1.2 g, 0.2 mmol), vinylyllicsilazane (3.8 g, 28.0 mmol) and AIBN (6 mg, 0.04 mmol) was dissolved in benzene (1 mL) and three freezes Gas was removed by performing a three freeze-evacuate-thaw cycle. The reaction mixture was sealed and then immersed in an oil preheated to 120 ° C. for 12 hours, as a result of which the mixture was dissolved in dichloromethane (5 mL) and precipitated in n-hexane to give a pale yellow solid, which was purified diblock air. Copolymer, PVSZ-SS-PEO was obtained.

Next, the self-assembled diblock copolymer will be described.

A thin film of diblock copolymer having a thickness of 20 nm or less was obtained by spin coating PVSZ-SS-PEO diluted in a benzene solution on a glass substrate at 2000 rpm for 30 seconds. The thin film was then treated for 10 hours at 30 ° C. under a benzene atmosphere in a hermetically sealed container to form a self-assembled PVSZ-SS-PEO block copolymer. To remove the PEO blocks, the treated membranes were soaked in 0.1 M DTT solution for 12 hours and then washed with ethanol.

In addition, in a PVSZ ₅₂ -SS-PEO ₁₁₃ diblock copolymer having a controlled molecular weight of 20,650 g.mol ^-1 (PDI = 1.16), as determined by gel-permeation chromatography (GPC) method In addition, the volume fraction of the inorganic block was controlled to about 0.7, which is expected to form hexagonal tissue in terms of phase transformation as calculated by Leibler and Matsen.

Specific chemical structure of as-synthesized PVSZ ₅₂ -SS-PEO ₁₁₃ was identified using ¹ H-NMR (Nuclear Magnetic Resonance) spectra. Figure 3 is a ¹ H-NMR spectrum, Figure 3 (a) shows the PVSZ ₅₂ -SS-PEO ₁₁₃ as it is synthesized, Figure 3 (b) is a view showing a state after reduction by DTT.

The signals at δ = 3.8 and 4.27 ppm are assigned to the proton groups of the PEO block, while the peaks at δ = 5.7-6.2 ppm and 4.4 ppm are unreacted vinyl groups and Si-H in the PVSZ block, respectively. Indicates the presence of a group. Signals at 2.8 ppm and 3.65 ppm were assigned to disulfide groups combined with PEO and PVSZ, respectively, which is evidence for the integrated disulfide groups in the PVSZ-SS-PEO block copolymers.

To demonstrate fine phase separation of the functionalized block copolymer, the spin-coated block copolymer thin film (˜20 nm thick) was treated under saturated benzene vapor for 10 hours. With this treatment, the block copolymer film was converted into an aligned phase separated form by orienting the PEO cylindrical microdomains in lateral ordering. From the image of the projection electron microscope (TEM), one can see the highly regular hexagonally aligned large domains of self-assembled PVSZ ₅₂ -SS-PEO ₁₁₃ with a pore diameter of ˜8 nm. FIG. 4 is a thin film (˜20 nm thick) of self-assembled PVSZ ₅₂ -SS-PEO ₁₁₃ block copolymer prepared by solvent treatment followed by removal of the PEO block, FIG. 4 (a) shows a TEM image, FIG. 4. (b) shows a small angle XRD pattern.

As shown in FIG. 4, the small angular X-ray diffraction pattern (SA-XRD) of the self-assembled PVSZ ₅₂ -SS-PEO ₁₁₃ shows a sharp peak at 2θ = 0.76, with a d-spacing of 9.89 nm. And a hexagonally packed cylindrical form with a pore diameter of ˜8.1 nm was formed. To selectively remove the PEO blocks and create chemically functionalized nanopores from the self-assembled PVSZ ₅₂ -SS-PEO ₁₁₃ thin film, the polymer film was immersed in dithiothreitol (DTT) solution for 12 hours, followed by ethanol Washed with. Inorganic PVSZ blocks remained on the surface with thiol-functionalized nanopores, while the PEO blocks were washed away.

As shown in FIG. 5, the FT-IR spectra show peaks at 1130 cm ⁻¹ and 860 cm ⁻¹ , corresponding to CO bonding and CH ₂ locking modes made in PEO blocks, respectively, and treated with DTT solution. After it was not seen, from this, it could be confirmed that the PEO block was removed from the polymer thin film. 5 is an FT-IR spectrum of the PVSZ ₅₂ -SS-PEO ₁₁₃ block copolymer, in which FIG. 5 (a) shows a state before reduction by DTT and FIG. 5 (b) shows a state after reduction by DTT.

In addition, as shown in FIG. 3, the ¹ H-NMR spectrum shows the appearance of the -SH peak at δ = 3.7 ppm after reduction by the DTT solution. These results indicate that the self-assembled PVSZ ₅₂ -SS-PEO ₁₁₃ was converted to inorganic PVSZ nanopores containing thiol functional groups on the surface by simple immersion in DTT solution.

To immobilize Au or Pd NPs in thiol-functionalized nanoporous thin film, self-assembled PVSZ films were immersed in HAuCl ₄ or palladium diacetate (Pd (OAc) ₂ ) solution, respectively, and hydrazine The solution was used to reduce the metals in the pores: It was found that the metal NPs produced in the solution phase could precipitate in the nanopores in a chemically induced position-selective manner by interaction between the metal and thiol groups. Au and Pd NPs with strong chemical affinity for -SH were successfully immobilized into self-assembled nanopore tissue, which was confirmed by TEM (see FIGS. 6A and 6C). Ag NPs have been effectively immobilized in self-assembled inorganic pores due to the effective chemical affinity between Ag and thiol groups, Figure 6 shows self-assembled nanoporous PVSZ films ( (A), (B) are Au nanoparticles, FIG. 6 (C), (D) are TEM images and HR-TEM of Pd nanoparticles. It is an enlarged version of the TEM image and the scale bar is 10 nm.

In the HR-TEM image (see FIGS. 6B and 6D) showing the interplanar spacing of 2.84 μs for Au NPs and 2.61 μs for Pd NPs corresponding to the (111) plane, The crystal structures of Au NPs and Pd NPs were observed. In addition, energy dispersive X-ray (EDX) spectra showing peaks at 2.1 keV and 2.9 keV show the identity of Au and Pd elements, respectively, in the pores of the self-assembled block copolymer (see FIG. 7). ). FIG. 7 illustrates EDX spectra of Au and Pd NPs immobilized on a self-assembled nanoporous thin film, in which FIG. 7A is Au NPs and FIG. 7B is Pd NPs. .

Au NPs and Pd NPs immobilized in the pores of self-assembled inorganic tissue have average particle sizes of 8.5 and 10 nm, respectively, and have a narrow size distribution (see FIG. 8). FIG. 8 shows self-assembled nanopores. FIG. 8A shows Au NPs, and FIG. 8B shows Pd NPs. The particle size distribution of Au and Pd NPs immobilized on the thin film is shown.

High resolution scanning electron microscopy (SEM) and atomic force microscopy (AFM) images will now be described with reference to FIG. 9 for critical data on successful immobilization of Au and Pd NPs in the pore tissue of self-assembled PVSZ films.

FIG. 9 shows SEM, AFM and depth profiles of various self-assembled nanoporous thin films from PVSZ ₅₂ -SS-PEO ₁₁₃ diblock copolymers, and FIGS. 9A and 9D show PEO blocks. After removal, FIGS. 9B and 9E show very regular and immobilized Au nanoparticles, FIGS. 9C and 9F show highly regular and immobilized Pd nanoparticles, and the scale bar is 100 nm. to be.

9 (A) shows a very regular array of nanoporous domains of self-assembled PVSZ films. The cross-sectional profile recorded across the AFM image (see FIG. 9 (D)) including the Si cantilevers indicates the presence of nanopores about 20 5 5 nm deep, indicating that the PVSZ-SS-PEO thin film Almost coincident with the thickness, it shows cylindrical nanoporous domains oriented perpendicular to the surface. SEM and AFM images of Au NPs and Pd NPs immobilized PVSZ films in FIGS. 9 (B)-(C) and (E)-(F) show a very regular array of NPs in a hexagonally aligned pattern.

The average size of the immobilized Au NPs was about 8.5 nm in diameter and about 4 nm in height, and about 10 nm in diameter and about 5 nm in height for the immobilized Pd NPs, which are respectively shown in FIGS. It is consistent with the TEM image shown in (C).

The surrounding PVSZ matrix, which does not have a chemical preference for metal NPs, acts as a barrier to the lateral diffusion of metal ion complexes, which leads to NP growth at limited pore positions in a size and position-selective manner. . Formation of narrowly dispersed NPs suggests the effectiveness of block copolymer-induced pores that act as stabilizers to prevent particle aggregation.

In addition, by adjusting the molecular weight of the block copolymer to manipulate the size, shape and functionality of the granulated domain, the size and spacing of the catalyst NPs could be controlled. In contrast, Au NPs were randomly immobilized or clustered into clusters on thiol-modified polyvinylsilazane (PVSZ-SH) monopolymer coated substrates due to the strong binding force between the major particles in the absence of a separation wall. This is different from the case of self-assembled block copolymers (see FIG. 10). FIG. 10 (A) shows TEM images of Au NPs immobilized with good alignment on self-assembled nanoporous polymers, and FIG. 10 (B) shows Au NPs randomly fixed on PVSZ-SH polymer films. It is a figure which shows the TEM image for comparison.

Next, the microchemical performance of the fixed bed microreactor according to the present invention will be described.

It is well known that metal NPs that are well sequestered without aggregation exhibit better catalytic efficiency than randomly aggregated metal catalysts. To identify these differences in organic reactions, we investigated the catalytic performance of chemically induced, position-selectively immobilized Au and Pd NPs on self-assembled nanoporous polymeric films and also used glass flasks for comparison. General bulk processes and randomly fixed metal NP catalysts were also investigated.

In the case of heterogeneous catalytic reactions in bulk processes, problems such as long reaction times, gradual catalyst losses and low durability have arisen. In this study, a fixed bed type microfluidic system was prepared by positioning very regular metal NPs in a vertically-aligned inorganic PVSZ nanoporous film in the reaction zone.

A soft lithography technique is used to prepare microchannels of 500 μm (width) x 50 μm (depth) x 16 cm (length) from fluoropolymers, and the microchannel tissue is self-assembled nanopores containing metal NPs. Placed on polymer film and then clamped to fully seal the channel (see FIGS. 1 and 11).

FIG. 11 is a view showing a manufacturing process of finely ordered metal nanoparticles immobilized on a self-assembling nanoporous thin film integrated in a microfluidic system having fluoropolymer microchannels for heterogeneous catalysis.

Fluoropolymers with strong organic solvent resistance have high optical clarity and are stable under various chemical and thermal conditions.

The solvent resistance of the thin film microfluidic reactor system was tested using a method of immersion in several solvents for several hours. At 80 ° C., the thin film microchannels showed good resistance to strongly swelling solvents containing toluene, AcOH, CH ₃ CN, or Ac ₂ O.

Au NPs are known to catalyze oxidation-change catalysis from 0-xylene (as simple arene) to biaryl in the presence of PhI (OAc) ₂ as oxidant. Biaryls are known as important structural components in natural products, pharmaceuticals, pesticides and substances. Accordingly, the catalytic performance of the Au NPs fixed bed microreactor was investigated by performing a homo-coupling reaction.

The reaction in the bulk process showed a low yield (37-65%) even after a long reaction time (17 hours) due to the aggregation of nanoparticles. In contrast, as described and compared in Table 1, Au NPs fixed bed microreactors showed good conversion yields in various solvents after reaction times shorter than 5 minutes.

The yield of biaryl in a very regular Au NPs catalytic microfluidic reactor was 64-90%, which is better than 28-51% in a simple microfluidic reactor with randomly fixed Au NPs. At high flow rates (ie short reaction times), the catalyst performance in fixed bed microreactors has been greatly improved compared to the catalyst performance in bulk reactions and simple microfluidic reactors.

At 5 minutes reaction time, the turnover frequency (TOF) of the fixed bed microreactor was increased to 544.2 h ⁻¹ , which is superior to the simple microfluidic reactor 306 h ⁻¹ and the bulk reaction (1.9 h ⁻¹ ). . Here, a simple microfluidic reactor is one in which a metal NP catalyst is precipitated on a thiol-modified PVSZ homopolymer coated substrate.

Table 1 shows the heterogeneous catalytic homo-coupling reaction ^a in ^a fixed bed microreactor with a fixed film containing very regular Au nanoparticles compared to simple microfluidic reactors and bulk reactions using various solvents. .

^a Reaction condition: substrate (10 mmol), PhI (OAc) ₂ (1 mmol), solvent (1 ml), 55 ° C. ^b Yield determined by GCMS.

Au catalysis was comparatively tested for the synthesis of epoxides, which are widely used as important intermediates for many fine chemicals and pharmaceuticals. Although several metal oxides, metal clusters and metal organic frameworks are used as catalysts, the most useful catalyst for good conversion and selectivity will be gold.

However, due to the agglomeration of gold nanoparticles in bulk phase reactions that greatly reduce catalyst activity and selectivity, recovery and reuse of catalysts are always a problem.

Here, Au NPs fixed bed microreactors were used for short conversions and epoxidation of olefins with high selectivity as shown in Table 2. Fixed bed microreactors showed a conversion of 73.8% of styrene and a significant selectivity of 77% for styrene oxide at the shortest reaction time (1 minute).

When the reaction time was extended to 10 minutes, a high selectivity for styrene oxide (90%) was achieved with a high styrene conversion (96.3%), which is more than that for a simple microfluidic reactor and bulk reaction for 6 hours. Very high. Significant improvements in the catalytic performance of very regular Au NPs catalysts may result from a large number of active sites with high stability due to isolated immobilization.

In addition, the well dispersed Au NP catalyst in the microfluidic reactor maximizes the catalytic performance, as the mass transfer to the immobilized NP catalyst is greatly improved due to the high surface-to-volume ratio in the limited microchannels. In addition, observation of 24 hours or more at a constant flow rate of 5 μl / min showed no leakage of the reactants and a decrease in conversion performance.

These results show that immobilized Au NPs on resistant self-assembled thin film films are effective fixed bed catalysts for highly efficient heterogeneous reactions. More importantly, the stabilization of Au NPs on the pore surface of the block copolymer, which prevents the aggregation of nanoparticles, may also contribute to prolongation of catalyst life. The adhesion stability of Au NPs to PVSZ pores was confirmed by applying sonication for 30 minutes (see FIG. 12). 12 is a diagram showing the adhesion stability of Au NPs on the substrate of the block copolymer, Figure 12 (A) is before the ultrasonic treatment, Figure 12 (B) shows the result of the ultrasonic treatment for 30 minutes, scale bar Is 100 nm.

No morphological changes of the inorganic nanostructures / NPs were observed, indicating that the NPs have high adhesion stability on the pore surface of the inorganic tissue due to the strong adhesion between the thiol groups on the pores and the NPs.

Table 2 shows the gold catalyst epoxidation of olefins in various reaction ^a systems.

^a Reaction conditions: substrate (1 mmol), tert-BuOOH (2 mmol), toluene (5 ml), 80 ° C.

^b Conversion and selectivity were determined by GCMS.

Similarly, fixed bed microreactors with very regular Pd NPs were subjected to heterogeneous catalysis. In particular, Heck's reaction was very important in the synthesis of complex organic molecules.

As shown in Table 3, the yield of 94.3% ethyl cyanate in a fixed bed microreactor for 12 minutes is more than twice the yield of 45.6% in a simple microfluidic reactor, which is 90% of the bulk reaction reached after 8 hours. Comparable to%

In addition, only a small deviation in product yield occurred during the repeated reactions for 10 hours, and no metal NPs were detected in the synthetic solution, which was inductively coupled plasma atomic emission spectroscopy (ICP-). AES), which again shows no leaching of the immobilized catalyst and good durability.

Finally, from the results of the three types of catalytic reactions presented so far, it can be seen that the microfluidic system integrated with the self-assembled inorganic pore thin film catalyst has excellent heterogeneous catalyst efficacy as a fixed bed microreactor. In addition, various nanobiotechnology sensing, such as surface-enhanced Raman scattering (SERS), in which Au NPs placed in size and selected locations in a controlled manner have plasmon-resonant optical properties It is also noteworthy that it can be applied.

Table 3 shows the heterogeneous catalytic Heck reaction in a fixed bed microreactor with a fixed film containing highly regular and immobilized Pd nanoparticles compared to a simple microfluidic reactor and a bulk reaction ^a .

^a Reaction conditions: substrate (1 mmol), ethyl acrylate (1 mmol), TEA (1 mmol), PEG (˜0.3 g), 80 ° C. ^b Yield determined by GCMS.

According to the present invention, newly synthesized PVSZ-SS-PEO diblock copolymers using disulfide bonds were used to create self-assembled PVSZ nanoporous tissues having -SH groups under mild conditions. Functionalized tissue allows for the immobilization of metal NPs on -SH functionalized pores in a chemically induced size and regioselective manner. Au or Pd NPs on the self-assembled polymer thin film were positioned in the microchannels by lithographic techniques, which could produce a fixed bed microreactor for heterogeneous catalytic microchemical reactions.

Solvent resistant fixed bed microreactors according to the present invention exhibited better catalytic performance than conventional bulk processes and randomly precipitated metal NPs catalyst systems in glass flasks. Accordingly, the present invention provides an effective method for fabricating a lab-on-a-chip system capable of eliciting new applications in the field of microchemical and biological sensors.

In the present invention, as shown in Figure 11, a thin film of a block copolymer having nanoparticles was coated on a glass substrate and processed to form an inorganic film having pores. A fluoropolymer mold was placed on the glass substrate and subsequently stamped onto the block copolymer / nanoparticle substrate via lithography techniques.

In the case of catalysis, the synthesis solution was injected from a syringe pump through a polytetrafluoroethylene (PTFE) tube into the fixed bed micro reactor shown in FIG. The reaction took place at the desired temperature and at various flow rates. After several minutes of reaction time, the synthetic solution was received at the outlet of the PTFE tube and analyzed by GC-MS.

Although the present invention has been described in detail with reference to the above embodiments, it is needless to say that the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit of the present invention.

The fixed bed microreactor according to the present invention and its manufacturing method are applied to a microchemical process.

Claims (8)

(a) synthesizing a self-assembled poly (vinylsilazane) -block-poly (ethylene oxide) diblock copolymer (PVSZ-SS-PEO),
(b) providing a thin film of PVSZ-SS-PEO in step (a) on a substrate,
(c) immersing the thin film prepared in step (b) in a reducing agent to clean the PEO block,
(d) obtaining a thiol-functionalized nanoporous thin film by step (c),
(e) selectively fixing metal nanoparticles to the nanopores,
(F) a method of producing a fixed bed micro-reactor comprising the step of clamping by placing a fine channel on the film to which the metal nanoparticles are fixed by the step (e). The method of claim 1,
PVSZ-SS-PEO in step (a) is polymerized by reversible addition fragmentation chain transfer (RAFT) of polyvinylsilazane (PVSZ) using a PEO-based macroinitiator containing a disulfide bond. Process for producing a fixed bed micro reactor, characterized in that synthesized. The method of claim 1,
The reducing agent is a method for producing a fixed bed micro reactor, characterized in that dithiothreitol (DTT) solution. The method of claim 1,
The metal nanoparticle is Au or Pd,
And the metal nanoparticles are selectively immobilized due to the chemical affinity between the Au or Pd metal and thiol groups. The method of claim 1,
Wherein said thin film is fixed to a lower surface in a fluoropolymer microchannel made by lithography technique. A micro reactor capable of allowing a fluid to be mixed while passing through a microchannel and discharging the mixed fluid,
Thin film with metal nanoparticles fixed in nanopores
A microchannel disposed on the thin film,
And the thin film is fixed to a lower surface of the microchannel. The method according to claim 6,
The metal nanoparticles are Au or Pd, Ag,
And the metal nanoparticles are selectively immobilized. The method according to claim 6,
The microchannel is a micro-reactor characterized in that consisting of fluorine polymer.

Images