JP5765709B2 - Amine-functionalized mesoporous carbon nanocage and method for producing the same - Google Patents

Description

  The present invention relates to a carbon nanocage grafted with an amine functional group and a production method thereof.

  The development of nanoporous materials for applications such as catalyst materials, electrode materials, adsorbents for large biomolecules, and templates is remarkable. Recently, among nanoporous materials, a technique for grafting a functional group such as acidic or basic to the surface of a carbon material to impart further functions has been studied.

  For example, it has been reported that a basic catalyst is synthesized by grafting an amine to a carbon nanotube (see, for example, Non-Patent Document 1). According to Non-Patent Document 1, a carboxylic acid group is introduced into a carbon nanotube, and then the carboxylic acid group is changed to a desired derivative, thereby succeeding in grafting an amine onto the carbon nanotube.

  However, since the reaction of Non-Patent Document 1 uses severe reaction conditions, the structure of the carbon nanotube may be broken, and the yield is not good. Moreover, since the reaction of the grafting of the amine of Non-Patent Document 1 is performed in steps, the operation becomes complicated. Furthermore, Non-Patent Document 1 uses a dangerous reagent that generates toxic waste and is not environmentally friendly. Therefore, development of a technique for grafting an amine to a nanoporous carbon material that is environmentally friendly, easy to operate, and good in yield is desired. In particular, it is preferable to have a technique for grafting amine while maintaining the shape of the nanoporous carbon material having a large specific surface area and a large pore volume among the nanoporous carbon materials.

  The object of the present invention is to provide an amine functionalized mesoporous carbon nanocage and a method for its production.

The amine-functionalized mesoporous carbon nanocage according to the present invention is a basic catalyst , a mesoporous carbon nanocage obtained by using a mesoporous silica as KIT-5 as a template, and the mesoporous carbon nanocage. Consisting of amines grafted on the surface and sidewalls of mesopores,
The amines are

Represented by
Here, R is selected from the group consisting of n-propyl, cyclohexyl, o-phenyl, n-butyl and p-pentyl, thereby achieving the above object.
The specific surface area of the amine-functionalized mesoporous carbon nano cage, pore size, and pore volume, ^{respectively,} 800m ² / ^{g~1300m 2 /g,3.5nm~4.5nm,} and 1.1 cm ³ / g It may be ˜1.6 cm ³ / g .
According to the present invention , the mesoporous carbon nanocage obtained by using the mesoporous silica which is KIT-5 as a template, and the above formula (1) grafted on the surface of the mesoporous carbon nanocage and the side wall of the mesopore method for producing a amine functionalized mesoporous carbon nano cage consisting of an amine compound represented are the mesoporous carbon nano cage obtained mesoporous silica is a KIT-5 as a template, peroxo ammonium and / Or adding to a solution containing sodium peroxosulfate salt to oxidize the mesoporous carbon nanocage and mixing the oxidized mesoporous carbon nanocage with carbodiimide, amines and dimethylformamide; Grafting said amines, and The carbodiimide is 1-ethyl-3 (3-dimethylaminopropyl) carbodiimide (EDCI), and the amines are selected from the group consisting of long-chain alkylamines, cycloalkylamines and aromatic amines. To achieve.
In the oxidizing step, the solution to which the mesoporous carbon nanocage is added may be stirred at 4 to 5 ° C. for 6 to 8 hours.
The grafting step further includes sonicating a mixture of the oxidized mesoporous carbon nanocage, carbodiimide, amines, and dimethylformamide, and heating and stirring the mixture. May be.
In the heating and stirring step, the mixture may be heated at a temperature of 60 ° C. to 70 ° C. and stirred for 22 hours to 24 hours.
The amines may be selected from the group consisting of n-propylamine, cyclohexylamine, o-phenylamine, n-butylamine and p-pentylamine.
The specific surface area of the amine-functionalized mesoporous carbon nano cage, pore size, and pore volume, ^{respectively,} 800m ² / ^{g~1300m 2 /g,3.5nm~4.5nm,} and 1.1 cm ³ / g It may be ˜1.6 cm ³ / g.
The amine functionalized mesoporous carbon nanocage may be a basic catalyst.

  The amine-functionalized mesoporous carbon nanocage according to the present invention is excellent in miscibility with various solvents including polar solvents since a given amine is grafted. The amine-functionalized mesoporous carbon nanocage according to the present invention reflects the shape of the mesoporous carbon nanocage obtained using the mesoporous silica which is KIT-5 as a template even if the amine is grafted, and has a large ratio. Has surface area and large pore volume. The amine-functionalized mesoporous carbon nanocage according to the present invention also functions as a basic catalyst that exhibits excellent product conversion ability and high selectivity for the formation of the desired product.

  A method for producing an amine-functionalized mesoporous carbon nanocage according to the present invention comprises adding a mesoporous carbon nanocage to a solution containing ammonium peroxosulfate and / or a salt of sodium peroxosulfate, Oxidizing and mixing the oxidized mesoporous carbon nanocage with carbodiimide, amines and dimethylformamide and grafting the amines. The step of grafting amines is extremely simple because it can be operated in one pot. In addition, since the production method of the present invention uses 1-ethyl-3 (3-dimethylaminopropyl) carbodiimide (EDCI) as the carbodiimide, it does not use dangerous reagents and is environmentally friendly.

Schematic diagram of amine functionalized mesoporous carbon nanocages according to the present invention Schematic of Claisen Schmidt reaction using amine functionalized mesoporous carbon nanocage according to the present invention as catalyst Diagram showing steps for producing amine functionalized mesoporous carbon nanocages according to the present invention Diagram showing the reaction procedure in the production of amine functionalized mesoporous carbon nanocages according to the present invention Diagram showing XRD pattern of mesoporous carbon nanocage Diagram showing nitrogen adsorption / desorption isotherm of mesoporous carbon nanocage Diagram showing pore size distribution of mesoporous carbon nanocages HRTEM image and electron mapping of mesoporous carbon nanocage The figure which shows the FTIR spectrum of CNC-PN of Examples 1-3, CNC-CYC, and CNC-OPD The figure which shows the thermogravimetric change of CNC-PN of Examples 1-3, CNC-CYC, and CNC-OPD. The figure which shows the HRTEM image of CNC-PN of Example 1. The figure which shows the nitrogen adsorption-and-desorption isotherm of CNC-PN, CNC-CYC, and CNC-OPD of Examples 1-3. The figure which shows the nitrogen adsorption-and-desorption isotherm of CNC-COPN of the comparative example 1. The figure which shows the pore size distribution of CNC-PN, CNC-CYC, and CNC-OPD of Examples 1-3. The figure which shows the pore diameter distribution of CNC-COPN of the comparative example 1 The figure which shows the XRD pattern of CNC-PN of Examples 1-3, CNC-CYC, and CNC-OPD CNC -COPN of Comparative Examples 1-3, shows the XRD pattern of the CNC -COCYC and CNC -COOPD The figure which shows 1H NMR spectrum of the product which reacted benzaldehyde and acetophenone using CNC-OPD of Example 3. The figure which shows 1H NMR spectrum of the product which reacted benzaldehyde and o-hydroxy acetophenone using CNC-OPD of Example 3. The figure which shows another 1H NMR spectrum of the product which reacted benzaldehyde and o-hydroxy acetophenone using CNC-OPD of Example 3.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same number is attached | subjected to the same element and the description is abbreviate | omitted.

  FIG. 1 is a schematic diagram of an amine functionalized mesoporous carbon nanocage according to the present invention.

  The amine-functionalized mesoporous carbon nanocage 100 according to the present invention includes a mesoporous carbon nanocage 110 and amines 120 grafted on the surface of the mesoporous carbon nanocage 110 and the side walls of the mesopores. As used herein, “amine functionalization” means that amines are grafted.

  The mesoporous carbon nanocage 110 is a carbon nanocage obtained using mesoporous silica which is KIT-5 as a template. The mesoporous carbon nanocage 110 has a crystal structure of a face-centered cubic lattice (space group Fm6m).

  KIT-5 is known to have a relatively small specific surface area and pore volume, with a plurality of pores positioned regularly and symmetrically in three dimensions. Reflecting such a shape of KIT-5, the porous carbon nanocage 110 includes a carbon main part 130 and a carbon bonding part 140 that bonds the carbon main part 130 to each other, as shown in FIG. . The carbon main part 130 is regularly and symmetrically positioned three-dimensionally (only two dimensions are shown in FIG. 1 for simplicity). The carbon main part 130 corresponds to the three-dimensionally arranged holes of KIT-5.

  As described above, the mesoporous carbon nanocage 110 has a structure in which a wide space (mesopore) is connected by the carbon main part 130 and the carbon bond part 140. Reflecting the small specific surface area and pore volume of KIT-5, the mesoporous carbon nanocage 110 has a large specific surface area and pore volume. The mesoporous carbon nanocage 110 has a cage-type (birdcage-like) space inside, and the space has a structure in which the inner diameter of the space is larger than the entrance of the space.

The amines 120 are grafted on the surface of the mesoporous carbon nanocage 110 and the side walls of the mesopores. In FIG. 1, for the sake of simplicity, a state in which the amines 120 are grafted in a plane is shown, but the grafting of the amines 120 is not limited thereto. The amine 120 is represented by the formula (1).

In formula (1), R is selected from the group consisting of long chain alkyl groups, cycloalkyl groups and aromatics, but preferably from n-propyl, cyclohexyl, o-phenyl, n-butyl and p-pentyl. Selected from the group consisting of Theoretically, the above-described general R is employed, but if R is bulky, the mesopores of the mesoporous carbon nanocage 110 may be broken. Therefore, any R selected from the group consisting of n-propyl, cyclohexyl, o-phenyl, n-butyl and p-pentyl can be grafted without breaking the mesopores.

The amine-functionalized mesoporous carbon nanocage 100 according to the present invention maintains the shape of the mesoporous carbon nanocage 110 even after the amines 120 are grafted, so a high specific surface area, a large pore size and a large Has a pore volume. Specifically, the specific surface area of the amine-functionalized mesoporous carbon nano cage 100 according to the present invention, pore size, and pore volume, ^{respectively,} 800m ² / ^{g~1300m 2 /g,3.5nm~4.5nm,} and ^a 1.1cm ³ /g~1.6cm 3 / g, the electrode material, which is equivalent to that of the catalyst material and the porous material of the adsorbent for.

  Furthermore, the amine-functionalized mesoporous carbon nanocage 100 according to the present invention has high miscibility with polar solvents such as water since the amines 120 are grafted. Therefore, it is highly convenient because even polar solvents can be easily dissolved while maintaining the characteristics of existing mesoporous carbon nanocages.

  Also, the amine-functionalized mesoporous carbon nanocage 100 according to the present invention functions as a basic catalyst since the amines 120 are grafted.

  FIG. 2 is a schematic diagram of the Claisen Schmidt reaction using the amine functionalized mesoporous carbon nanocage according to the present invention as a catalyst.

  When the amine-functionalized mesoporous carbon nanocage 100 according to the present invention is used as a basic catalyst, chalcone 3 and flavanone 4 can be synthesized from benzaldehyde 1 and 2-hydroxy o-acetophenone 2 via Claisen Schmidt condensation. It should be noted that the product conversion by the amine functionalized mesoporous carbon nanocage 100 according to the present invention and the high selectivity for the formation of flavanone 4 is comparable to existing commercial basic catalysts (eg MgOH). Do / surpass. In addition, biocompatible carbon-based heterogeneous catalysts are advantageous in terms of environmental issues.

FIG. 3 is a diagram illustrating steps for producing an amine functionalized mesoporous carbon nanocage according to the present invention.
FIG. 4 shows a reaction procedure in the production of amine functionalized mesoporous carbon nanocages according to the present invention.

  Step S310: Mesoporous carbon nanocage 110 (FIG. 4) is oxidized. Specifically, mesoporous carbon nanocages obtained using mesoporous silica as KIT-5 as a template are added to a solution containing ammonium peroxosulfate and / or sodium peroxosulfate and oxidized. KIT-5 and mesoporous carbon nanocages may be synthesized with reference to Japanese Patent No. 4724877.

  Preferably, the solution to which the mesoporous carbon nanocage is added is stirred at 4 ° C to 5 ° C for 6 hours to 8 hours. As a result, the mesoporous carbon nanocage is oxidized (410 in FIG. 4).

  S320: An amine is grafted on the oxidized mesoporous carbon nanocage 410. Specifically, oxidized mesoporous carbon nanocage 410 is mixed with carbodiimide, amines and dimethylformamide. Here, the carbodiimide is 1-ethyl-3 (3-dimethylaminopropyl) carbodiimide (EDCI), and the amines are selected from the group consisting of long-chain alkylamines, cycloalkylamines and aromatic amines. The amines are preferably selected from the group consisting of n-propylamine, cyclohexylamine, o-phenylamine, n-butylamine and p-pentylamine. Theoretically, the above-mentioned general amines are adopted, but if the selected amines are bulky, the mesopores of the oxidized mesoporous carbon nanocage 410 may be broken. Therefore, any amine selected from the group consisting of n-propylamine, cyclohexylamine, o-phenylamine, n-butylamine and p-pentylamine can be grafted without breaking the mesopores.

  Specifically, the grafting step includes a step of sonicating a mixture of oxidized mesoporous carbon nanocage 410, carbodiimide, amines, and dimethylformamide, and a step of heating and stirring the mixture. In addition. Specific heating and stirring may be performed by heating the mixture at a temperature of 60 ° C. to 70 ° C. and stirring for 22 to 24 hours. As a result, amines are grafted onto the oxidized mesoporous carbon nanocage 410 to produce the amine-functionalized mesoporous carbon nanocage 100 according to the present invention.

  Since step S320 can be operated with one pot, it is extremely simple. Also, 1-ethyl-3 (3-dimethylaminopropyl) carbodiimide (EDCI) employed in step S310 is not toxic and is environmentally friendly.

  The present invention will now be described in detail using specific examples, but it should be noted that the present invention is not limited to these examples.

[Reference Example 1]
Prior to the production of the amine functionalized mesoporous carbon nanocages, the templates mesoporous silica KIT-5 and mesoporous carbon nanocages were produced.

  KIT-5 was produced using Pluronic F127 (EO106PO70EO106) as the structural support and tetraethylorthosilicate (TEOS) as the silica precursor.

  F127 (2.5 g) was dissolved in distilled water (120 g) and concentrated hydrochloric acid (35 wt% HCl, 2.5 g). TEOS (12 g) was quickly added to the mixture with stirring at 45 ° C. The mixture was then allowed to react at 45 ° C. for 24 hours. The reaction product was heated in a static state at 100 ° C. for 24 hours and hydrothermally treated. The resulting solid product was filtered and dried at 100 ° C. without washing. The solid product after filtration was baked at 550 ° C. to remove F127. In this manner, KIT-5 was produced.

  A mesoporous carbon nanocage was manufactured using the manufactured KIT-5. Mesoporous carbon nanocages were prepared using KIT-5 as a structural support, sucrose as a carbon source, and sulfuric acid as a catalyst.

  KIT-5 (1 g) was added to a solution of sucrose (0.75 g) and sulfuric acid (0.08 g) in water (2.5 g). This mixture was kept in an oven at 100 ° C. for 6 hours, then heated to 160 ° C. and held for another 6 hours.

  Sucrose (0.5 g), sulfuric acid (0.05 g) and water (2.5 g, where the weight ratio of silica to water was 2.5) was added to the heated and retained product and again The above heat treatment was performed to obtain sucrose that was completely polymerized and carbonized into the mesopores of KIT-5.

  In this way, the KIT-5-polymer composite product was kept in a nitrogen flow at 877 ° C. for 6 hours and thermally decomposed. As a result, the polymer of the composite product was carbonized. KIT-5 in the carbonized composite product was dissolved with hydrofluoric acid (5 wt%). The residue was filtered, washed several times with ethanol, and dried at 120 ° C. Thus, a mesoporous carbon nanocage obtained using mesoporous silica as KIT-5 as a template was obtained.

  The X-ray diffraction (XRD) pattern of the mesoporous carbon nanocage was measured using a Rigaku diffractometer (CuKα ray λ = 0.154 nm). The results are shown in FIG.

  The nitrogen adsorption / desorption isotherm of the mesoporous carbon nanocage was measured at −196 ° C. using a Quantachrome Autosorb 1 adsorption analyzer. A sample for measurement was prepared by degassing a mesoporous carbon nanocage at 80 ° C. for 24 hours in a vacuum using a degas port of an adsorption analyzer. The results are shown in FIG.

  The specific surface area of the mesoporous carbon nanocage was calculated from the adsorption / desorption isotherm using the Brunauer-Emmett-Teller (BET) method. Further, the pore size distribution of the mesoporous carbon nanocage was determined from the adsorption branch of the adsorption / desorption isotherm using the Barrett-Joyner-Halenda (BJH) method. The results are shown in FIG.

  High resolution electron microscope (HRTEM) images and electron mapping of the mesoporous carbon nanocages were observed using a scanning electron microscope JEOL JEM-2100F. Samples for observation were prepared by sonicating mesoporous carbon nanocages in ethanol for 5 minutes and depositing on a copper grid. The observation condition was an acceleration voltage of 200 kV. The results are shown in FIG.

  FIG. 5 is a diagram showing an XRD pattern of a mesoporous carbon nanocage.

According to the XRD pattern, peaks corresponding to diffractions of (111), (200) and (220) of the face-centered cubic lattice (space group Fm6m) were confirmed in the range of 2θ = 0.7-3. The lattice constant a ₀ obtained from the diffraction peak (111) was 20.68 nm (see Table 2).

  FIG. 6 is a diagram showing a nitrogen adsorption / desorption isotherm of a mesoporous carbon nanocage.

According to the nitrogen adsorption / desorption isotherm, hysteresis of type H2 (type IV in the IUPAC classification) was shown. This means that mesopores (pores having a diameter of 2 to 50 nm) exist in the mesoporous carbon nanocages, and nitrogen adsorption due to capillary condensation occurs at a relative pressure of 0.5 to 0.8. It suggests. The specific surface area and pore volume of the mesoporous carbon nanocage determined from the nitrogen adsorption / desorption isotherm using the BET equation were 1515 m ² / g and 2.0 cm ³ / g, respectively (see Table 2). .

  FIG. 7 is a diagram showing the pore size distribution of mesoporous carbon nanocages.

  The pore diameter of the mesoporous carbon nanocage was 5.2 nm.

  FIG. 8 is a diagram showing an HRTEM image and electron mapping of a mesoporous carbon nanocage.

  FIGS. 8A and 8B are an HRTEM image of a plane parallel to the mesopores and a cross section of the mesopores, and an electron mapping thereof, respectively. In FIG. 8, light stripes with high contrast indicate pore sidewalls (eg, 110 in FIG. 1), and dark stripes with contrast indicate mesopores (eg, the space in FIG. 1). 8 (a) and 8 (b), it was found that the obtained mesoporous carbon nanocage has a highly ordered structure and a pore distribution. In these images, bright spots were regularly arranged (inset in FIG. 8), and it was confirmed that the images had a cage-type porous structure.

  From the above, it was confirmed that a mesoporous carbon nanocage that is a replica of KIT-5 was obtained using KIT-5.

  In Example 1, an amine-functionalized mesoporous carbon nanocage in which the mesoporous carbon nanocage produced in Reference Example 1 was grafted with an amine whose R is n-propyl in formula (1) was produced.

  The mesoporous carbon nanocage (100 mg) produced in Reference Example 1 was added to a solution of ammonium peroxosulfate (APS) (6 gms) to oxidize the mesoporous carbon nanocage (step S310 in FIG. 3). The APS solution was prepared by dissolving APS (1M) in sulfuric acid (2M). In the oxidation, the solution to which the mesoporous carbon nanocage was added was stirred at 5 ° C. for 8 hours.

  The oxidized mesoporous carbon nanocage was filtered and the residue was washed with distilled water to completely remove the remaining sulfide. The oxidized mesoporous carbon nanocage thus obtained was placed in an oven and dried in a vacuum for 24 hours.

  Oxidized mesoporous carbon nanocage (100 mg), 1-ethyl-3 (3-dimethylaminopropyl) carbodiimide (EDCI, 100 mg) as carbodiimide, 1,2-propylenediamine among long-chain alkylamines as amines (500 mg) and dimethylformamide (DMF, 2 mL) were mixed, and the amines were grafted (step S320 in FIG. 3).

  Specifically, the graft was sonicated with a mixture of oxidized mesoporous carbon nanocage, EDCI, 1,2-propylenediamine and DMF for 15 minutes and heated in a 70 ° C. oil bath. While stirring for 24 hours.

  The product thus obtained was centrifuged and then washed with water to remove unreacted EDCI. The product was then washed with ethanol to remove unreacted 1,2-propylenediamine from the product. The product was dried in vacuum. The product thus obtained is referred to as CNC-PN.

  The Fourier transform infrared spectroscopy (FT-IR) spectrum of CNC-PN was measured using an FT-IR spectrophotometer (Perkin-Elmer Spectrum 100). For the measurement, KBr was used as a reference. The results are shown in FIG.

  Thermogravimetric analysis (TGA) of CNC-PN was performed. The results are shown in FIG. Similarly to the reference example, an HRTEM image of CNC-PN was observed, and a nitrogen adsorption / desorption isotherm was measured. The results are shown in FIGS. 11 and 12, respectively.

  The specific surface area and pore volume of CNC-PN were calculated from the nitrogen adsorption / desorption isotherm using the BET equation. The results are shown in Table 2. The pore size distribution of CNC-PN was determined. The results are shown in FIG. Similarly to the reference example, the XRD pattern of CNC-PN was measured. The results are shown in FIG. Elemental analysis of CNC-PN was measured using an Analyst AA300 spectrometer. The results are shown in Table 2.

  Next, the function of CNC-PN as a basic catalyst was examined using the Claisen-Schmidt reaction. DMF (2 mL), benzaldehyde (1.0 mmol), and acetophenone / o-hydroxyacetophenone (1.0 mmol) were refluxed with stirring in the presence of NAP-MgO (0.100 g) and CNC-PN. Thin film chromatography (TLC) was used to confirm complete reaction.

  CNC-PN was removed by a centrifuge, and the filtrate was concentrated to obtain a crude product. The crude product was purified by column chromatography using silica gel (hexane / ethyl acetate, 8/2, v / v).

  The NMR spectrum of the purified product was measured and identified using a nuclear magnetic resonance apparatus (NMR). The results are shown in Table 3.

  The supernatant liquid separated by the centrifuge was discharged, the remaining CNC-PN was washed with ethanol, and the organic extract was collected. CNC-PN was dried in vacuum, the above reaction was performed 4 times, and the stability of CNC-PN as a basic catalyst was examined.

  In Example 2, an amine-functionalized mesoporous carbon nanocage in which the mesoporous carbon nanocage produced in Reference Example 1 was grafted with an amine whose R is cyclohexyl in formula (1) was produced.

  The procedure was the same as that of Example 1, except that 1,2-cyclohexyldiamine (500 mg) was used as the amine in cyclohexylamine. The product thus obtained is referred to as CNC-CYC.

  For CNC-CYC, as in Example 1, the FT-IR spectrum, thermogravimetric change, nitrogen adsorption / desorption isotherm, and pore diameter distribution were measured, and the specific surface area and pore volume were calculated. The results are shown in FIG. 9, FIG. 10, FIG. 12, FIG. 14, FIG.

  The function of CNC-CYC as a basic catalyst was examined in the same manner as in Example 1. The NMR spectrum was measured and the identified results are shown in Table 3.

  In Example 3, an amine-functionalized mesoporous carbon nanocage in which the mesoporous carbon nanocage produced in Reference Example 1 was grafted with an amine in which R is o-phenyl in formula (1) was produced.

  The procedure was the same as in Example 1 except that 1,2-diaminebenzene (500 mg) was used as the amine. The product thus obtained is referred to as CNC-OPD.

  For CNC-OPD, as in Example 1, the FT-IR spectrum, thermogravimetric change, nitrogen adsorption / desorption isotherm, and pore diameter distribution were measured, and the specific surface area and pore volume were calculated. The results are shown in FIG. 9, FIG. 10, FIG. 12, FIG. 14, FIG.

  The function of CNC-OPD as a basic catalyst was examined in the same manner as in Example 1. The NMR spectrum of the purified product was measured, and the identified results are shown in Table 3 and FIGS.

Comparative Example 1

Comparative Example 1 was the same as Example 1 except that another carbodiimide N, N′-dichlorocarbodiimide (DCC) was used instead of EDCI. The product thus obtained is referred to as CNC-COPN. For CNC- COPN, nitrogen adsorption / desorption isotherm, pore size distribution and XRD pattern were measured. The results are shown in FIG. 13, FIG. 15, and FIG.

Comparative Example 2

Comparative Example 2 was the same as Example 2 except that DCC was used instead of EDCI. The product thus obtained is referred to as CNC-COCYC. The XRD pattern was measured for CNC- COCYC. The results are shown in FIG.

Comparative Example 3

Comparative Example 3 was the same as Example 3 except that DCC was used instead of EDCI. The product thus obtained is referred to as CNC-COOPD. The XRD pattern was measured for CNC- COOPD. The results are shown in FIG.

For simplicity, the production conditions of Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 1.

  FIG. 9 is a diagram showing FTIR spectra of CNC-PN, CNC-CYC, and CNC-OPD of Examples 1 to 3.

In any FTIR spectrum, a broad band was observed in the range of 3200 to 3560 cm ⁻¹ . This band is a band formed by free NH ₂ stretching vibration and NH stretching vibration. On the other hand, a band of about 3081cm ^-1 in FTIR spectra of CNC-PN, band at about 2948cm ^-1 in FTIR spectra of CNC-CYC, and a band of about 2933cm ^-1 in FTIR spectra of CNC-OPD is the amine coupling It is a band of C—H bond stretching vibration of an alkyl or allyl group.

The sharp band of about 1593 cm ^{−1 and} the shoulder of 1453 cm ⁻¹ seen in any FTIR spectrum are the band of the C═O group stretching vibration and the N—H bond bending vibration. Moreover, the band of about 1220 cm ⁻¹ is caused by C—N stretching vibration. The results of these FTIR spectra were found to be similar to the results of FTIR spectra of carbon nanotubes grafted with amines as described in Non-Patent Document 1. From the above, it is suggested that the amines were grafted to the mesoporous carbon nanocages by the production method of the present invention.

  FIG. 10 is a diagram showing thermogravimetric changes of CNC-PN, CNC-CYC, and CNC-OPD of Examples 1 to 3.

  Curves (a) to (c) in FIG. 10 represent thermogravimetric changes of CNC-PN, CNC-CYC, and CNC-OPD, respectively. In FIG. 10, region A (about 100 ° C.) shows the loss of adsorbed water molecules due to heating. This indicates that CNC-PN, CNC-CYC, and CNC-OPD can adsorb water, and were found to be hydrophilic. From the above, it was found that the amine-functionalized mesoporous carbon nanocage of the present invention is miscible with polar solvents such as water.

  Region B, on the other hand, shows the loss of bound amine due to heating. The decomposition temperatures of any CNC-PN, CNC-CYC and CNC-OPD are shown to be much higher than the boiling point of the amine. From the above, it was shown that amines were stably bound to mesoporous carbon nanocages by the production method of the present invention.

  FIG. 11 is a diagram showing an HRTEM image of the CNC-PN of the first embodiment.

  FIGS. 11A and 11B are HRTEM images of a plane parallel to the mesopores and a cross section of the mesopores, respectively. In FIG. 11, bright stripes with contrast indicate pore sidewalls (eg, 110 in FIG. 1), and dark stripes with contrast indicate mesopores (eg, the space in FIG. 1). 11 (a) and (b) were found to be substantially similar to FIGS. 8 (a) and (b). From this, it was found that the highly ordered structure and pore distribution in the mesoporous carbon nanocage used were maintained even after the amines were grafted by the production method of the present invention. Although not shown, similar HRTEM images were obtained for Examples 2 and 3.

  12 is a graph showing nitrogen adsorption / desorption isotherms of CNC-PN, CNC-CYC, and CNC-OPD in Examples 1 to 3. FIG.

  The nitrogen adsorption / desorption isotherms (a) to (c) in FIG. 12 represent the nitrogen adsorption / desorption isotherms of CNC-PN, CNC-CYC, and CNC-OPD, respectively. All of the nitrogen adsorption / desorption isotherms showed hysteresis of the H2 type (IV type in the IUPAC classification), similar to the mesoporous carbon nanocage. From this, it was found that the structure of the mesoporous carbon nanocage used was maintained even after the amines were grafted by the production method of the present invention. Table 2 shows the specific surface areas and pore volumes of CNC-PN, CNC-CYC, and CNC-OPD determined from the nitrogen adsorption / desorption isotherm using the BET equation.

  FIG. 13 is a view showing a nitrogen adsorption / desorption isotherm of CNC-COPN of Comparative Example 1.

  According to FIG. 13, the nitrogen adsorption / desorption isotherm showed hysteresis, but had a shape different from that of FIG. From this, it was found that the structure of the mesoporous carbon nanocage used could not be maintained after grafting amines by using DCC as carbodiimide.

  FIG. 14 is a graph showing pore size distributions of CNC-PN, CNC-CYC, and CNC-OPD in Examples 1 to 3.

  Distributions (a) to (c) in FIG. 14 represent the pore size distributions of CNC-PN, CNC-CYC, and CNC-OPD, respectively. Each pore size is about 4 nm (CNC-PN: 4.2 nm, CNC-CYC: 4.3 nm and CNC-OPD: 3.7 nm) smaller than the pore size (about 5 nm) before the amines are grafted. Met. This is due to pore clogging caused by the presence of amines in the pore space (pore channel) in the mesoporous carbon nanocage. This pore blockage was most noticeable in the CNC-OPD of Example 3. It is expected that amines having aromatic rings are stacked in the pore space (pore channel), resulting in pore clogging. That is, it is suggested that CNC-OPD may have more amines.

  According to Table 2, the specific surface area, pore diameter, and pore volume of each of Examples 1 to 3 were within the respective ranges of the mesoporous carbon nanocage before the amines were grafted. The specific surface area, pore diameter, and pore volume of Examples 1 to 3 were all smaller than those of the mesoporous carbon nanocages, suggesting that the amines were grafted to the mesoporous carbon nanocages. .

  For example, the specific surface area and pore volume of the CNC-OPD of Example 3 were significantly reduced. From this, it can be understood that the most amines were grafted in CNC-OPD among Examples 1 to 3, and as a result, the specific surface area and the pore volume were most reduced. In addition, the results of elemental analysis show that all amines are grafted, and in particular, many amines are grafted in the CNC-OPD of Example 3.

  FIG. 15 is a view showing the pore size distribution of CNC-COPN of Comparative Example 1.

  The pore diameter of CNC-COPN was about 4 nm, as in FIG. 14, but the pore volume was dramatically reduced due to its shape. This also indicates that the structure of the mesoporous carbon nanocage used cannot be maintained after grafting amines by using DCC as carbodiimide.

  FIG. 16 is a diagram showing XRD patterns of CNC-PN, CNC-CYC, and CNC-OPD of Examples 1 to 3.

  FIG. 16 also shows the XRD pattern (XRD pattern in FIG. 5) of the mesoporous carbon nanocage (CNC) for reference. All XRD patterns showed diffraction peaks of (111), (200) and (220), similar to the XRD pattern of the mesoporous carbon nanocage before the amines were grafted. The diffraction peaks of (200) and (220) were broad. This suggests that the porous structure is maintained as a whole, although it is caused by disorder of the porous structure due to amines grafted on the surface of the mesoporous carbon nanocage and the side walls of the pores.

As shown in Table 2, the lattice constant a ₀ calculated from the XRD pattern was smaller than that of the mesoporous carbon nanocage before the amines were grafted. Specifically, the lattice constant of CNC-CYC of Example 2 was the most reduced. This is because the size of the 1,2-diaminocyclohexane (CYC) molecule is larger than that of the 1,2-diaminopropane (PN) molecule, so that the lattice spacing d is increased by CYC grafting, and the lattice constant is This is because it decreases. On the other hand, in the case of o-phenylenediamine (OPD), since the bond length is shortened due to the inherent aromaticity, the molecular size is smaller than that of CYC and PN. Therefore, the coupling of OPD does not influence the lattice spacing of CYC so much.

FIG. 17 is a diagram showing XRD patterns of CNC- COPN, CNC- COCYC, and CNC- COOPD of Comparative Examples 1 to 3.

  In any XRD pattern, the diffraction peak was broad and the diffraction intensity was reduced, unlike that of FIG. This also indicates that the structure of the mesoporous carbon nanocage used cannot be maintained after grafting amines by using DCC as carbodiimide. From the above, it was confirmed that the carbodiimide suitable for grafting amines to the mesoporous carbon nanocage is 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide (EDCI).

  Table 3 shows the properties of the CNC-PN, CNC-CYC and CNC-OPD of Examples 1 to 3 as basic catalysts. For reference, Table 3 also shows the characteristics of mesoporous carbon nanocages in which amines are not grafted as Reference Example 1 and MgOH, which is an existing basic catalyst, as Comparative Example 4.

  18 is a diagram showing a 1H NMR spectrum of a product obtained by reacting benzaldehyde and acetophenone using the CNC-OPD of Example 3. FIG.

  According to FIG. 18, the product was found to be 3,4,4 ', 6'-tetrahydroxychalcone. Other types of products were not observed.

  When benzaldehyde and acetophenone were reacted using CNC-PN, CNC-CYC, and CNC-OPD of Examples 1 to 3, all produced 3,4,4 ′, 6′-tetrahydroxychalcone, and flavanone Was not generated.

FIG. 19 is a diagram showing a 1H NMR spectrum of a product obtained by reacting benzaldehyde and o-hydroxyacetophenone using CNC-OPD of Example 3.
FIG. 20 is a diagram showing another 1H NMR spectrum of a product obtained by reacting benzaldehyde and o-hydroxyacetophenone using CNC-OPD of Example 3.

  According to FIG. 19, it was found that a part of the product was 2-hydroxychalcone. Moreover, according to FIG. 20, it turned out that a part of product is flavanone.

  According to Table 3, mesoporous carbon nanocages not grafted with amines did not show any function as a basic catalyst.

  As described above, in all of Examples 1 to 3, the reaction of benzaldehyde and acetophenone does not show the selectivity of the product, and 3,4,4 ′, 6′-tetrahydroxychalcone is produced. I understood. On the other hand, in any of Examples 1 to 3, it was found that when benzaldehyde and o-hydroxybenacetophenone were reacted, two types of products, chalcone and flavanone, were produced, and the product had selectivity.

  From the above, the amine-functionalized mesoporous carbon nanocage of the present invention functions as a basic catalyst, has an excellent product conversion ability, and a desired product (here, 3,4,4 ′, 6 ′). -It was confirmed to have a high selectivity for the formation of tetrahydroxychalcone, chalcone or flavanone).

  Among them, the high selectivity of the CNC-OPD of Example 3 as a basic catalyst is higher than that of CNC-OPD compared to CNC-PN and CNC-CYC as described with reference to Table 2 and Table 1. It originates in having many amines. Although the basicity of free OPD is said to be less than that of free PN, the amount of amines grafted to mesoporous carbon nanocages is also highest in CNC-OPD, resulting in the highest Can exhibit basicity.

  Furthermore, in the case of the CNC-OPD of Example 3, OPD can be three-dimensionally concentrated on the surface and pore sidewalls by π stacking. As a result, the reactant and product diffusion paths are reduced, the contact time between the reactants and the grafted OPD is increased, and much of the o-hydroxychalcone is converted to the corresponding flavanone. This suggests that the reactivity of the amine-functionalized mesoporous carbon nanocage according to the present invention as a basic catalyst can be controlled by the grafted amines.

  Moreover, although Claisen-Schmidt reaction of Examples 1-3 was performed in presence of a solvent (DMF), when DMF was not used, the yield fell (not shown). This is due to the fact that the use of a solvent facilitates the diffusion of substances into the pores and channels of the amine-functionalized mesoporous carbon nanocages according to the present invention.

  With reference to Table 3 again, Examples 1 to 3 and Comparative Example 4 are compared. All of Examples 1 to 3 showed conversion rates comparable to MgOH, which is a commercially available basic catalyst. Especially, CNC-OPD of Example 3 showed the selectivity of a high product as a basic catalyst, and it turned out that a flavanone can be produced | generated efficiently. The CNC-OPD of Example 3 can produce flavanone more efficiently than MgOH, which is the existing basic catalyst of Comparative Example 4. This is due to the presence of OPD in the pores and channels, so that products can be formed when reactants diffuse into the pores. Thus, as the reactant diffuses into the pores and channels, the reactant is exposed to OPD for extended periods of time, facilitating the selectivity of the reaction to the corresponding flavanone.

  Furthermore, when the above-mentioned Claisen-Schmidt reaction was carried out 4 times using the basic catalysts of Examples 1 to 3, although there was a slight decrease in yield in each reaction, there was no substantial change. This indicates that the amine-functionalized mesoporous carbon nanocage according to the present invention can be reused as a basic catalyst. The slight decrease in yield is due to a slight loss of the basic catalyst during the separation after each reaction, and can be ignored.

  The amine-functionalized mesoporous carbon nanocage according to the present invention is excellent in miscibility with various solvents including polar solvents since a given amine is grafted. The amine-functionalized mesoporous carbon nanocage according to the present invention reflects the shape of the mesoporous carbon nanocage obtained using mesoporous silica which is KIT-5 as a template, and has a large specific surface area and a large pore volume. The amine-functionalized mesoporous carbon nanocage according to the present invention also functions as a basic catalyst that exhibits excellent product conversion ability and high selectivity for the formation of the desired product.

100 Amine-functionalized mesoporous carbon nanocage 110 Mesoporous carbon nanocage 120 Amines 130 Carbon main part 140 Carbon bond part 410 Oxidized mesoporous carbon nanocage

Y. Wang et al., Chem. Phys. Lett. 2005, 402, 96

Claims (9)

A mesoporous carbon nanocage obtained by using a mesoporous silica as KIT-5 as a template;
An amine grafted on the surface of the mesoporous carbon nanocage and the side wall of the mesopore,
The amines are

Represented by
Wherein R is selected from the group consisting of n-propyl, cyclohexyl, o-phenyl, n-butyl and p-pentyl ;
Amine-functionalized mesoporous carbon nanocages that are basic catalysts . The specific surface area of the amine-functionalized mesoporous carbon nano cage, pore size, and pore volume, ^{respectively,} 800m ² / ^{g~1300m 2 /g,3.5nm~4.5nm,} and 1.1 cm ³ / g The amine-functionalized mesoporous carbon nanocage of claim 1, which is ˜1.6 cm ³ / g. A method of manufacturing a A amine functionalized mesoporous carbon nano cage,
The amine-functionalized mesoporous carbon nanocage is a mesoporous carbon nanocage obtained by using a mesoporous silica as KIT-5 as a template, on the surface of the mesoporous carbon nanocage and on the side walls of the mesopores. It is composed of grafted amines, and the amines are

Wherein R is selected from the group consisting of n-propyl, cyclohexyl, o-phenyl, n-butyl and p-pentyl;
A mesoporous carbon nanocage obtained using mesoporous silica as a template of KIT-5 is added to a solution containing ammonium peroxosulfate and / or a salt of sodium peroxosulfate to oxidize the mesoporous carbon nanocage. Steps,
Mixing the oxidized mesoporous carbon nanocage with carbodiimide, amines and dimethylformamide and grafting the amines;
The carbodiimide is 1-ethyl-3 (3-dimethylaminopropyl) carbodiimide (EDCI),
The method wherein the amines are selected from the group consisting of long chain alkyl amines, cycloalkyl amines and aromatic amines. The method according to claim 3, wherein in the oxidizing step, the solution to which the mesoporous carbon nanocage is added is stirred at 4 ° C. to 5 ° C. for 6 hours to 8 hours. The grafting step comprises:
Sonicating the mixture of oxidized mesoporous carbon nanocage, carbodiimide, amines and dimethylformamide;
The method of claim 3, further comprising heating and stirring the mixture. The method according to claim 5, wherein the heating and stirring step comprises heating the mixture at a temperature of 60C to 70C and stirring for 22 to 24 hours. 4. The method of claim 3, wherein the amines are selected from the group consisting of n-propylamine, cyclohexylamine, o-phenylamine, n-butylamine and p-pentylamine. The amine-functionalized mesoporous carbon nanocage has a specific surface area, a pore size, and a pore volume of 800 m, respectively. ² / G-1300m ² / G, 3.5 nm to 4.5 nm, and 1.1 cm ³ /G-1.6cm ³ 4. The method of claim 3, wherein / g. 4. The method of claim 3, wherein the amine functionalized mesoporous carbon nanocage is a basic catalyst.