CN113663670A - Nitro-aromatic hydrocarbon high-selectivity reduction catalyst, and preparation method and application thereof - Google Patents

Nitro-aromatic hydrocarbon high-selectivity reduction catalyst, and preparation method and application thereof Download PDF

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CN113663670A
CN113663670A CN202111030662.XA CN202111030662A CN113663670A CN 113663670 A CN113663670 A CN 113663670A CN 202111030662 A CN202111030662 A CN 202111030662A CN 113663670 A CN113663670 A CN 113663670A
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temperature
isopropanol
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黄涛
张明明
赵燕熹
张道洪
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South Central Minzu University
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South Central University for Nationalities
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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
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
    • B01J23/46—Ruthenium, rhodium, osmium or iridium
    • B01J23/468—Iridium
    • B01J35/50—
    • B01J35/51—
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
    • C07C209/30—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds
    • C07C209/32—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds by reduction of nitro groups
    • C07C209/36—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds by reduction of nitro groups by reduction of nitro groups bound to carbon atoms of six-membered aromatic rings in presence of hydrogen-containing gases and a catalyst
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C213/00—Preparation of compounds containing amino and hydroxy, amino and etherified hydroxy or amino and esterified hydroxy groups bound to the same carbon skeleton
    • C07C213/02—Preparation of compounds containing amino and hydroxy, amino and etherified hydroxy or amino and esterified hydroxy groups bound to the same carbon skeleton by reactions involving the formation of amino groups from compounds containing hydroxy groups or etherified or esterified hydroxy groups
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C215/00—Compounds containing amino and hydroxy groups bound to the same carbon skeleton
    • C07C215/68—Compounds containing amino and hydroxy groups bound to the same carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings and hydroxy groups bound to acyclic carbon atoms or to carbon atoms of rings other than six-membered aromatic rings of the same carbon skeleton

Abstract

The invention belongs to the technical field of nano materials and preparation thereof, and particularly discloses a high-selectivity reduction catalyst for nitroareneAn agent, a preparation method and application thereof. The invention uses iridium trichloride as a metal precursor, isopropanol/ethanol as a solvent and a reducing agent, a hydroxyl-terminated hyperbranched polymer (H102) as a carrier, and keeps N-channel by utilizing supermolecule self-assembly of the H102 in the isopropanol/ethanol2Performing oil bath reaction for 1H at 100 ℃ to prepare an Ir @ H102 compound; and calcining the Ir @ H102 for 2H at the temperature of 350-. Ir @ H102-350 is applied to catalytic hydrogenation of nitroaromatic, can realize rapid high-selectivity hydrogenation conversion of nitrobenzene and derivatives thereof into corresponding arylamine at room temperature (25 ℃) and H of 1.5MPa2Hydrogenation reaction is carried out for 30min under pressure, 100 percent conversion of the nitroaromatic hydrocarbon and 99.9 percent selectivity of the corresponding arylamine are achieved, and the catalyst has excellent stability and reusability and wide industrial application prospect.

Description

Nitro-aromatic hydrocarbon high-selectivity reduction catalyst, and preparation method and application thereof
Technical Field
The invention relates to the technical field of novel nano materials and preparation thereof, in particular to a nitroaromatic high-selectivity reduction catalyst and a preparation method and application thereof.
Background
The arylamine compound is an important organic chemical raw material and a fine chemical intermediate, is generally prepared by deep processing of an aromatic nitro compound serving as a raw material, is widely applied to the production fields of medicines, rubber, dyes, pesticides, other fine chemicals and the like, and occupies a very important position in chemical production. Attempts have been made to achieve rapid and efficient conversion of aromatic nitro compounds at ambient temperature conditions. However, the selective synthesis of aromatic amines from aromatic nitro compounds has hitherto required a longer reaction time or a higher reaction temperature or a higher hydrogen pressure. The aim of the people is to realize the 100 percent conversion rate and 100 percent selectivity of arylamine of aromatic nitro compound catalytic hydrogenation synthesis at normal temperature. Many studies have been reported on the application of platinum group metals as typical catalysts to the catalytic hydrogenation of aromatic nitro compounds. However, to date, no platinum group metal catalyst has been able to achieve 100% conversion and 100% product selectivity for the synthesis of aromatic amines by the rapid direct hydrogenation of aromatic nitro compounds at ambient temperature using hydrogen as a reducing agent. The relatively mild reaction conditions reported at present have the reaction temperature of over 50 ℃ and the reaction time of over 1.5 h. Therefore, a nano catalytic reaction system with high activity, high selectivity and high stability based on platinum group metals is designed, the aromatic nitro compound is quickly and efficiently selectively converted into aromatic amine at normal temperature, and the method has very important significance and application value.
Hyperbranched polymers (HBP) starting from a central nucleus and comprising a branched monomer ABnThe polymer is stretched step by step to form a highly branched three-dimensional quasi-spherical structure, various functional groups are distributed in the molecule and on the surface, and the molecule structure comprises a part of linear structural units and a large number of internal cavities. The HBP contains abundant functional groups including hydroxyl, amino, carboxyl and the like in the interior and on the surface, shows properties which are completely different from those of corresponding linear molecules, and can be applied to the fields of drug carriers, genetic engineering, nano materials, self-assembled supermolecule systems, catalyst carriers and the like. HBP has unique advantages in the aspects of encapsulating small molecules or inorganic nanoparticles and guiding self-assembly of inorganic precursors, and can be used as a monomolecular micelle template to prepare functional metal nanoparticles and functional nano-porous materials, so that in-situ reduction of metal ions and in-situ limited domain growth of the nanoparticles are realized. At the same time, the unique structure of HBP makes it undergo various interesting self-assemblies in different solvents. HBP-based solvent selective self-assembly can form different supermolecular self-assembly structures in different solvents. Abundant polar groups of a supermolecule self-assembly body formed by the HBP can be used as proper metal ion coordination sites, so that more metal ions can be complexed, and the in-situ reduction of the metal ions can be promoted under certain conditions; the three-dimensional space network and the multi-stage cavity can provide good confined space, and can better realize the confined growth and the stability of the metal nano particles, thereby obtaining the metal nano material based on HBP confined stability.
Disclosure of Invention
The invention aims to provide a nitroaromatic high-selectivity reduction catalyst, and a preparation method and application thereof. The invention designs and synthesizes metal Ir nano particles with stable hyperbranched polymer self-assembly structure limited domain by taking a hydroxyl-terminated hyperbranched polymer (H102, the structural formula is shown in figure 1) as a carrier and a template, and applies the metal Ir nano particles to the catalytic hydrogenation of nitroarene to realize the rapid and efficient selective conversion of the nitroarene at room temperature.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
the invention provides a high-selectivity reduction catalyst for nitroaromatic hydrocarbon, which is a partially carbonized metal Ir nanoparticle with stable terminal hydroxyl hyperbranched polymer self-assembly structure limited domain, and the average particle size of the metal Ir nanoparticle is 1.5 nm.
The invention also provides a preparation method of the nitroaromatic high-selectivity reduction catalyst, which comprises the following steps:
(1) ir @ H102 complex preparation: weighing a certain amount of NaHCO3Putting a certain amount of hydroxyl-terminated hyperbranched polymer H102 into a reaction bottle, adding a certain amount of isopropanol, and stirring for 25-30min until the solid is completely dissolved; adding a certain amount of IrCl3Stirring the isopropanol solution for 25-30min to uniformly mix the solution; the mixed solution was sonicated for 10min, followed by N addition2Removing air; finally, the reaction flask is placed in an oil bath pot, and the opening of N is kept2Reacting at constant temperature of 100 ℃ for 60 min; stopping the reaction, cooling to room temperature, and removing isopropanol by adopting a rotary evaporation method at 45 ℃ or a normal-temperature centrifugal separation method to obtain an Ir @ H102 compound;
(2) ir @ H102-T catalyst preparation: transferring the Ir @ H102 compound in the step (1) into a porcelain boat, and drying the porcelain boat in a constant-temperature air-blast drying oven at 60 ℃ for one night; then placing the mixture in a tube furnace, and introducing N2Gas, after the gas flow is stabilized, setting calcining temperature and heating program, and its heating rate is 5 deg.C/min-1Calcining for 2 hours after reaching the set temperature; and naturally cooling to room temperature after the calcination is finished, taking out and grinding to obtain the composite nano catalyst, wherein the calcination temperature is marked as Ir @ H102-T, and T refers to the value of the set calcination temperature of 350-400 ℃.
Preferably, in step (1), the amount of the reactant is determined as IrCl3/H102/NaHCO3Mole ofThe ratio is 1/2/5, wherein IrCl is obtained after the materials in the reaction system are mixed3The concentration is 0.025 mol.L-1。
Preferably, in the step (2), the set calcination temperature is 350 ℃.
Preferably, in step (1), isopropanol is removed by rotary evaporation at 45 ℃.
Alternatively, in the step (1), the isopropanol as the solvent and the reducing agent in the reaction system may be entirely replaced with ethanol.
The invention also provides an application of the high-selectivity reduction catalyst for the nitroarene in the catalytic hydrogenation of the nitroarene, which specifically comprises the following steps:
a certain amount of nitroaromatic, a certain amount of solvent and a certain amount of Ir @ H102-T (T is more than or equal to 350 and less than or equal to 400) catalyst are sequentially added into an autoclave, and H is used2After 5 times of air replacement, a certain H is maintained2Stirring and reacting for a certain time at a certain temperature under the pressure; filtering and recovering the catalyst, and removing the solvent from the filtrate by rotary evaporation to obtain the product.
Further, the nitroaromatic hydrocarbon is nitrobenzene and series derivatives thereof, including nitrobenzene, p-chloronitrobenzene, o-chloronitrobenzene, m-chloronitrobenzene, p-bromonitrobenzene, p-fluoronitrobenzene, p-nitrotoluene, o-nitrotoluene, m-nitrotoluene, p-ethyl nitrobenzene, p-nitroacetophenone, p-nitrobenzyl alcohol and the like.
Further, the solvent is methanol, water, ethanol, isopropanol, etc.; preferably, the solvent is methanol.
Furthermore, the dosage ratio of the nitroaromatic to the solvent to the catalyst is 1mmol/10mL/5-10 mg.
Preferably, said H2The pressure was 1.5 MPa.
Preferably, the certain temperature is between room temperature (25 ℃) and 30 ℃.
Preferably, the stirring reaction time is 30 min.
Compared with the prior art, the invention has the advantages and beneficial effects that:
(1) the invention provides a nitroarene highly-selective reduction catalyst, which adopts a hydroxyl-terminated hyperbranched polymer H102 (the structural formula is shown in figure 1) as a carrier and a template, utilizes self-assembly of the hyperbranched polymer in a selected isopropanol solvent to synthesize metallic Ir nano-particles with stable hyperbranched polymer self-assembly structure limited domain, and then calcines at 350 ℃ to obtain partially-carbonized metallic Ir nano-particles with stable hydroxyl-terminated hyperbranched polymer self-assembly structure limited domain. The high-stability ultrafine metal Ir nano catalyst (Ir @ H102-350) is prepared by adopting a partial carbonization technology for the first time.
(2) The prepared catalyst Ir @ H102-350 is applied to catalytic hydrogenation of nitroaromatic hydrocarbon, can realize rapid high-selectivity hydrogenation conversion of nitrobenzene and derivatives thereof into corresponding arylamine at room temperature (25 ℃) and H of 1.5MPa2Hydrogenation reaction is carried out for 30min under pressure, 100 percent conversion of the nitroaromatic hydrocarbon and 99.9 percent selectivity of the corresponding arylamine are achieved, and the catalyst has excellent stability and reusability and wide industrial application prospect.
(3) The hydroxyl-terminated hyperbranched polymer H102 adopted in the process of preparing the partially carbonized hydroxyl-terminated hyperbranched polymer self-assembly metal Ir nano catalyst with stable structural confinement is low in price and easy to obtain, the carbonization temperature is low, the process is simple, the cost is low, and the large-scale industrial production is easy to realize.
Drawings
FIG. 1 shows the structure of the most important component of the hydroxyl-terminated hyperbranched polymer H102 used in the present invention.
FIG. 2 is a TEM image of Ir @ H102-350 catalyst synthesized in example 1 of the present invention;
FIG. 3 is an SEM image of Ir @ H102-350 catalyst synthesized in example 1 of the present invention;
FIG. 4 is a scanning line of HAADF-STEM and EDX of Ir @ H102-350 catalyst synthesized in example 1 of the present invention, wherein: (a) HAADF-STEM picture, (b) EDX line scan picture, and (c) Ir element line scan distribution picture;
FIG. 5 is an XRD spectrum of Ir @ H102-350 catalyst synthesized in example 1 of the present invention;
FIG. 6 is an XPS spectrum (Ir) of Ir @ H102-350 catalyst synthesized in example 1 of the present invention;
FIG. 7 is an XPS spectrum (O and C) of Ir @ H102-350 catalyst synthesized in example 1 of the present invention;
FIG. 8 is an SEM image of Ir @ H102-400 catalyst synthesized in example 2 of the present invention;
FIG. 9 is an SEM image of Ir @ H102-350C catalyst synthesized in example 3 of the present invention;
FIG. 10 is an SEM image of Ir @ H102-350E catalyst synthesized in example 4 of the present invention;
FIG. 11 is a GC spectrum of the corresponding products of example 5, example 6, example 7 and example 8 of the present invention;
FIG. 12 is a GC spectrum of the corresponding reaction product of example 9 of the present invention and its comparison with other samples;
fig. 13 is a TEM photograph of corresponding Ir nanoparticles, Ir @ H102, in example 9 of the present invention, wherein: (a) TEM image of Ir nanoparticle, (b) TEM image of Ir @ H102;
FIG. 14 is a GC spectrum of the corresponding products of example 10, example 11 and example 12;
FIG. 15 is a GC spectrum of the corresponding reaction product of example 13 according to the present invention;
FIG. 16 is a GC spectrum of the corresponding reaction product of example 14 according to the present invention;
FIG. 17 is a bar graph of conversion and selectivity of the reaction products of example 15 of the present invention.
Detailed Description
The technical scheme of the invention is further explained by combining the embodiment as follows:
in the following examples, H102(HyPer H10 series products) was obtained from Wuhan super-branched resin science and technology Limited (the basic structural formula of the most essential component is shown in FIG. 1), IrCl3Purchased from Kunming noble research New materials science and technology Co., Ltd; isopropanol, methanol, nitrobenzene and other reagents are all available from the national pharmaceutical group chemical reagents, ltd.
Example 1
The synthesis method of the nitroarene highly-selective reduction catalyst of the embodiment comprises the following steps:
(1) ir @ H102 complex preparation: 210mg of NaHCO are weighed3And 1180mg of H102 inAdding 15mL of isopropanol into a 50mL three-neck round-bottom flask, and stirring for 30min until the hyperbranched substance is completely dissolved; 5mL of 0.1 mol. L was added thereto-1IrCl3Stirring the isopropanol solution for 30min to uniformly mix the solution; the mixed solution was sonicated for 10min, followed by N addition2Removing air; finally, the reaction flask is placed in an oil bath pot, and the opening of N is kept2Reacting at constant temperature of 100 ℃ for 60 min; the reaction was stopped and cooled to room temperature. And (4) removing isopropanol by rotary evaporation at the temperature of 45 ℃ to obtain Ir @ H102 complex.
(2) Ir @ H102-350 catalyst preparation: transferring the Ir @ H102 compound into a porcelain boat, and placing the porcelain boat in a constant-temperature air-blowing drying oven for drying overnight at 60 ℃; then placing the mixture in a tube furnace, and introducing N2Gas, after the gas flow is stable, setting the calcining temperature to 350 ℃ and the temperature-raising program, wherein the temperature-raising rate is 5 ℃ min-1Calcining for 2h at 350 ℃; and after the calcination is finished, naturally cooling to room temperature, taking out and grinding to obtain the composite nano catalyst which is marked as Ir @ H102-350.
TEM shows that the average particle size of the metallic Ir nanoparticles in the Ir @ H102-350 catalyst obtained in example 1 is 1.5nm, as shown in FIG. 2.
SEM testing further showed that the partially carbonized hyperbranched self-assembled structures of Ir @ H102-350 catalyst obtained in example 1 exhibited a large amount of spherical aggregation characteristic, with a balloon size of about 50 nm. As shown in fig. 3.
HAADF-STEM and EDX testing further showed that the Ir @ H102-350 catalyst obtained in example 1 was a hollow sphere packing structure. As shown in fig. 4, wherein: (a) HAADF-STEM, (b) EDX line scan, and (c) Ir element line scan distribution.
XRD analysis shows that the 2 theta of four characteristic diffraction peaks of Ir in the Ir @ H102-350 catalyst obtained in example 1 are respectively positioned at 40.66 degrees, 47.31 degrees, 69.14 degrees and 83.45 degrees and respectively correspond to the (111), (200), (220) and (311) crystal planes of the simple substance Ir, and the synthesized Ir nanoparticles belong to a face-centered cubic (FCC) structure. The diffraction peak has a wider peak shape, which is related to the smaller average particle size of Ir nanoparticles. The single H102 self-assembly has poor crystallinity and a broad peak is observed only at 16 degrees, but the diffraction peak of the H102 self-assembly disappears in Ir @ H102-350, which indicates that the H102 self-assembly is crosslinked to form amorphous carbon. As shown in fig. 5.
XPS testing showed Ir4f in the Ir @ H102-350 catalyst obtained in example 15/2、Ir4f7/2The electron binding energy of (A) is 63.70eV and 60.75eV, the peak interval is 2.95eV, and the molecular weight is represented by a zero valence Ir0. As shown in fig. 6.
XPS tests showed that the Ir @ H102-350 catalyst obtained in example 1 had O and C elements, confirming its partial carbonization characteristics. As shown in fig. 7.
Example 2
The synthesis method of the nitroarene highly-selective reduction catalyst of the embodiment comprises the following steps:
(1) ir @ H102 complex preparation: 210mg of NaHCO are weighed3And 1180mg of H102 in a 50mL three-necked round-bottom flask, adding 15mL of isopropanol, and stirring for 30min until the hyper-branched substance is completely dissolved; 5mL of 0.1 mol. L was added thereto-1IrCl3Stirring the isopropanol solution for 30min to uniformly mix the solution; the mixed solution was sonicated for 10min, followed by N addition2Removing air; finally, the reaction flask is placed in an oil bath pot, and the opening of N is kept2Reacting at constant temperature of 100 ℃ for 60 min; the reaction was stopped and cooled to room temperature. And (4) removing isopropanol by rotary evaporation at the temperature of 45 ℃ to obtain Ir @ H102 complex.
(2) Ir @ H102-400 catalyst preparation: transferring the Ir @ H102 compound into a porcelain boat, and placing the porcelain boat in a constant-temperature air-blowing drying oven for drying overnight at 60 ℃; then placing the mixture in a tube furnace, and introducing N2Gas, after the gas flow is stable, setting the calcining temperature to 400 ℃ and the temperature-raising program, wherein the temperature-raising rate is 5 ℃ min-1Calcining for 2h at 400 ℃; and after the calcination is finished, naturally cooling to room temperature, taking out and grinding to obtain the composite nano catalyst which is marked as Ir @ H102-400.
SEM test shows that the partially carbonized hyperbranched self-assembled structure of the Ir @ H102-400 catalyst obtained in example 2 has obvious hollow spherical morphology, but most of hollow spheres are partially collapsed and cracked due to severe carbonization. As shown in fig. 8.
Example 3
The synthesis method of the nitroarene highly-selective reduction catalyst of the embodiment comprises the following steps:
(1) ir @ H102 complex preparation: 210mg of NaHCO are weighed3And 1180mg of H102 in a 50mL three-necked round-bottom flask, adding 15mL of isopropanol, and stirring for 30min until the hyper-branched substance is completely dissolved; 5mL of 0.1 mol. L was added thereto-1IrCl3Stirring the isopropanol solution for 30min to uniformly mix the solution; the mixed solution was sonicated for 10min, followed by N addition2Removing air; finally, the reaction flask is placed in an oil bath pot, and the opening of N is kept2Reacting at constant temperature of 100 ℃ for 60 min; the reaction was stopped and cooled to room temperature. The isopropanol was removed by centrifugation at room temperature to give Ir @ H102 complex.
(2) Ir @ H102-350C catalyst preparation: transferring the Ir @ H102 compound into a porcelain boat, and placing the porcelain boat in a constant-temperature air-blowing drying oven for drying overnight at 60 ℃; then placing the mixture in a tube furnace, and introducing N2Gas, after the gas flow is stable, setting the calcining temperature to 350 ℃ and the temperature-raising program, wherein the temperature-raising rate is 5 ℃ min-1Calcining for 2h at 350 ℃; and naturally cooling to room temperature after the calcination is finished, taking out and grinding to obtain the composite nano catalyst which is marked as Ir @ H102-350C.
SEM tests show that the partially carbonized hyperbranched self-assembled structure of the Ir @ H102-350C catalyst obtained in example 3 presents a honeycomb-shaped porous structure. As shown in fig. 9.
Example 4
The synthesis method of the nitroarene highly-selective reduction catalyst of the embodiment comprises the following steps:
(1) ir @ H102 complex preparation: 210mg of NaHCO are weighed3And 1180mg of H102 in a 50mL three-neck round-bottom flask, adding 15mL of ethanol, and stirring for 30min until the hyperbranched product is completely dissolved; 5mL of 0.1 mol. L was added thereto-1IrCl3Stirring the ethanol solution for 30min to uniformly mix the solution; the mixed solution was sonicated for 10min, followed by N addition2Removing air; finally, the reaction flask is placed in an oil bath pot, and the opening of N is kept2Reacting at constant temperature of 100 ℃ for 60 min; the reaction was stopped and cooled to room temperature. And (3) removing ethanol by rotary evaporation at the temperature of 45 ℃ to obtain the Ir @ H102 compound.
(2) Ir @ H102-350E catalyst preparation: compounding Ir @ H102Transferring the substance into a porcelain boat, and drying in a constant temperature blast drying oven at 60 ℃ overnight; then placing the mixture in a tube furnace, and introducing N2Gas, after the gas flow is stable, setting the calcining temperature to 350 ℃ and the temperature-raising program, wherein the temperature-raising rate is 5 ℃ min-1Calcining for 2h at 350 ℃; and naturally cooling to room temperature after the calcination is finished, taking out and grinding to obtain the composite nano catalyst which is marked as Ir @ H102-350E.
SEM tests show that the partially carbonized hyperbranched self-assembled structure of the Ir @ H102-350E catalyst obtained in example 3 has a spherical assembled structure, and unlike Ir @ H102-350, the spheres are irregular, have non-uniform sizes and are loosely aggregated. As shown in fig. 10.
Example 5
The application of the nitroarene highly-selective reduction catalyst of the embodiment comprises the following steps:
1.0mmol of nitrobenzene, 10mL of methanol and 5mg of Ir @ H102-350 catalyst are sequentially added into an autoclave and are stirred and mixed uniformly; by H2After air was replaced 5 times, 1.5MPa H was maintained2The reaction was stopped by stirring under pressure at room temperature (25 ℃) for 30min, and the catalyst was removed by filtration through a microporous membrane.
GC analysis of the product by an internal standard method (ethylbenzene is used as an internal standard substance) shows that the conversion rate of nitrobenzene is 100 percent, and the selectivity of aniline is more than 99.9 percent. As shown in fig. 11 (detailed in the figure, "1-methanol"). The corresponding peak area data are shown in Table 1.
TABLE 1
Figure BDA0003245089160000101
Example 6
The application of the nitroarene highly-selective reduction catalyst of the embodiment comprises the following steps:
1.0mmol of nitrobenzene, 10mL of water and 5mg of Ir @ H102-350 catalyst are sequentially added into an autoclave and are stirred and mixed uniformly; by H2After air was replaced 5 times, 1.5MPa H was maintained2The reaction was stopped by stirring under pressure at room temperature (25 ℃) for 30min, and the catalyst was removed by filtration through a microporous membrane.
GC analysis of the product by an internal standard method (ethylbenzene is used as an internal standard substance) shows that the conversion rate of nitrobenzene is 99.3 percent, and the selectivity of aniline is 97.1 percent. As shown in fig. 11 (see in detail "4-water"). The corresponding peak area data are as described in table 1 above.
Example 7
The application of the novel nitroarene highly-selective reduction catalyst of the embodiment comprises the following steps:
1.0mmol of nitrobenzene, 10mL of ethanol and 5mg of Ir @ H102-350 catalyst are sequentially added into an autoclave and are stirred and mixed uniformly; by H2After air was replaced 5 times, 1.5MPa H was maintained2The reaction was stopped by stirring under pressure at room temperature (25 ℃) for 30min, and the catalyst was removed by filtration through a microporous membrane.
GC analysis of the product by an internal standard method (ethylbenzene is used as an internal standard substance) shows that the conversion rate of nitrobenzene is 96.0 percent, and the selectivity of aniline is 97.6 percent. As shown in fig. 11 (detailed in fig. 2-ethanol). The corresponding peak area data are as described in table 1 above.
Example 8
The application of the nitroarene highly-selective reduction catalyst of the embodiment comprises the following steps:
1.0mmol of nitrobenzene, 10mL of isopropanol and 5mg of Ir @ H102-350 catalyst are sequentially added into an autoclave and are stirred and mixed uniformly; by H2After air was replaced 5 times, 1.5MPa H was maintained2The reaction was stopped by stirring under pressure at room temperature (25 ℃) for 30min, and the catalyst was removed by filtration through a microporous membrane.
GC analysis of the product by an internal standard method (ethylbenzene is used as an internal standard substance) shows that the conversion rate of nitrobenzene is 45.3 percent, and the selectivity of aniline is 91.9 percent. As shown in fig. 11 (detailed in fig. 3-isopropanol). The corresponding peak area data are as described in table 1 above.
Example 9
The application of the novel nitroarene highly-selective reduction catalyst of the embodiment comprises the following steps:
1.0mmol of nitrobenzene, 10mL of methanol and 5mg of Ir @ H102-400 catalyst are sequentially added into an autoclave and are stirred and mixed uniformly; by H2Replacement ofAfter air for 5 times, the pressure is maintained at 1.5MPa H2The reaction was stopped by stirring under pressure at room temperature (25 ℃) for 30min, and the catalyst was removed by filtration through a microporous membrane.
Under the same conditions, a control experiment was carried out using H102, Ir nanoparticles, and Ir @ H102 synthesized in example 1, respectively, as catalysts. The synthesis method of the Ir nano particles comprises the following steps: example 1 no H102 was added in the step of synthesizing Ir @ H102.
GC analysis of the product by an internal standard method (ethylbenzene is used as an internal standard substance) shows that the conversion rate of nitrobenzene is 89% under the catalysis of the Ir @ H102-400 catalyst, and the selectivity of aniline is more than 99%. As shown in fig. 12 (see in detail "5-Ir @ H102-400").
A TEM photograph of the corresponding Ir nanoparticles, Ir @ H102, is shown in fig. 13, wherein: (a) TEM image of Ir nanoparticle, and (b) TEM image of Ir @ H102.
Example 10
The application of the nitroarene highly-selective reduction catalyst of the embodiment comprises the following steps:
1.0mmol of nitrobenzene, 10mL of methanol and 5mg of Ir @ H102-350C catalyst are sequentially added into an autoclave and stirred and mixed uniformly; by H2After air was replaced 5 times, 1.5MPa H was maintained2The reaction was stopped by stirring under pressure at room temperature (25 ℃) for 30min, and the catalyst was removed by filtration through a microporous membrane.
GC analysis of the product by an internal standard method (ethylbenzene is used as an internal standard substance) shows that the conversion rate of nitrobenzene catalyzed by the Ir @ H102-350C catalyst is 59 percent, and the selectivity of aniline is more than 99 percent. As shown in fig. 14 (detailed in "1-25 ℃ C. 5 mg" in the figure).
Example 11
The application of the novel nitroarene highly-selective reduction catalyst of the embodiment comprises the following steps:
1.0mmol of nitrobenzene, 10mL of methanol and 8mg of Ir @ H102-350C catalyst are sequentially added into an autoclave and stirred and mixed uniformly; by H2After air was replaced 5 times, 1.5MPa H was maintained2The reaction was stopped by stirring under pressure at room temperature (25 ℃) for 30min, and the catalyst was removed by filtration through a microporous membrane.
GC analysis of the product by an internal standard method (ethylbenzene is used as an internal standard substance) shows that the conversion rate of nitrobenzene catalyzed by the Ir @ H102-350C catalyst is 100 percent, and the selectivity of aniline is more than 99.9 percent. As shown in fig. 14 (see in detail "2-25 ℃ C. 8 mg" in the figure).
Example 12
The application of the nitroarene highly-selective reduction catalyst of the embodiment comprises the following steps:
1.0mmol of nitrobenzene, 10mL of methanol and 5mg of Ir @ H102-350C catalyst are sequentially added into an autoclave and stirred and mixed uniformly; by H2After air was replaced 5 times, 1.5MPa H was maintained2Reacting under pressure at 30 deg.C for 30min while stirring, stopping reaction, and filtering with microporous membrane to remove catalyst.
GC analysis of the product by an internal standard method (ethylbenzene is used as an internal standard substance) shows that the conversion rate of nitrobenzene catalyzed by the Ir @ H102-350C catalyst is 81.9 percent, and the selectivity of aniline is more than 99 percent. As shown in fig. 14 (detailed in "3-30 ℃ 5 mg" in the figure).
Example 13
The application of the nitroarene highly-selective reduction catalyst of the embodiment comprises the following steps:
1.0mmol of nitrobenzene, 10mL of methanol and 5mg of Ir @ H102-350E catalyst are sequentially added into an autoclave and are stirred and mixed uniformly; by H2After air was replaced 5 times, 1.5MPa H was maintained2The reaction was stopped by stirring under pressure at room temperature (25 ℃) for 30min, and the catalyst was removed by filtration through a microporous membrane.
GC analysis of the product by an internal standard method (ethylbenzene is used as an internal standard substance) shows that the conversion rate of the Ir @ H102-350E catalyst for catalyzing nitrobenzene is 95.5 percent, and the selectivity of aniline is more than 99.9 percent. As shown in fig. 15.
Example 14
The application of the nitroarene highly-selective reduction catalyst of the embodiment comprises the following steps:
1.0mmol of nitrobenzene derivative, 10mL of methanol and 5mg of Ir @ H102-350 catalyst are sequentially added into an autoclave and stirred and mixed uniformly; by H2After air was replaced 5 times, 1.5MPa H was maintained2Stirring under pressure at room temperature (25 deg.C) for 30min, stopping reaction, and filtering with microporous filterThe catalyst was removed by membrane filtration.
GC analysis of the product by an external standard method shows that the conversion rate of different nitrobenzene derivatives catalyzed by the Ir @ H102-350 catalyst is 100 percent, and the selectivity of corresponding arylamine is more than 99 percent. The data are shown in table 2; the GC spectrum is shown in FIG. 16.
TABLE 2
Figure BDA0003245089160000141
Example 15
The application of the nitroarene highly-selective reduction catalyst of the embodiment comprises the following steps:
1.0mmol of nitrobenzene, 10mL of methanol and 5mg of Ir @ H102-350 catalyst are sequentially added into an autoclave and are stirred and mixed uniformly; by H2After air was replaced 5 times, 1.5MPa H was maintained2The reaction was stirred at room temperature (25 ℃) for 30min under pressure, and stopped. The catalyst was separated by centrifugation, washed 2 times with ethanol, dried overnight in a constant temperature forced air drying oven at 60 ℃ and then used in the next catalytic hydrogenation experiment, and the hydrogenation cycle was repeated 9 times in this way.
GC analysis of the product shows that the Ir @ H102-350 catalyst is used for catalyzing nitrobenzene hydrogenation for 9 times, the nitrobenzene conversion rate is 100%, and the aniline selectivity is more than 99%, as shown in figure 17.
Finally, it should be noted that: the above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof. Any modification, equivalent replacement, equivalent magnification, improvement and the like made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (10)

1. The nitroarene highly-selective reduction catalyst Ir @ H102-T is a partially-carbonized hydroxyl-terminated hyperbranched polymer H102 self-assembled structure-limited stable metallic Ir nanoparticle, and the average particle size of the metallic Ir nanoparticle is 1.5 nm;
the preparation method of the nitroaromatic high-selectivity reduction catalyst Ir @ H102-T comprises the following steps: iridium trichloride is taken as a metal precursor, isopropanol is taken as a solvent and a reducing agent, a hydroxyl-terminated hyperbranched polymer H102 is taken as a carrier, and NaHCO is3IrCl is used as an additive after all materials in a reaction system are mixed3/H102/NaHCO3In a molar ratio of 1/2/5, IrCl3The concentration is 0.025 mol.L-1Carrying out oil bath reaction for 60min at 100 ℃ in an inert atmosphere to obtain a hydroxyl-terminated hyperbranched polymer loaded Ir nanocomposite, which is marked as Ir @ H102; and (2) calcining the Ir @ H102 at the temperature of 350-400 ℃ for 2H under an inert atmosphere to obtain Ir @ H102-T, wherein T refers to the numerical value of the calcination temperature and has the unit of ℃.
2. The nitroarene highly selective reduction catalyst Ir @ H102-T according to claim 1, characterized in that the isopropanol is replaced by ethanol.
3. A process for the preparation of the nitroarene highly selective reduction catalyst Ir @ H102-T according to any one of claims 1 or 2, characterized in that it comprises the following steps:
(1) ir @ H102 complex preparation: weighing a certain amount of NaHCO3Putting a certain amount of hydroxyl-terminated hyperbranched polymer H102 into a reaction bottle, adding a certain amount of isopropanol, and stirring until the solid is completely dissolved; adding a certain amount of IrCl3Stirring the isopropanol solution for 25-30min to uniformly mix the solution; the mixed solution was sonicated for 10min, followed by N addition2Removing air; finally, the reaction flask is placed in an oil bath pot, and the opening of N is kept2Reacting at constant temperature of 100 ℃ for 60 min; stopping the reaction, cooling to room temperature, and removing isopropanol by adopting a rotary evaporation method at 45 ℃ or a normal-temperature centrifugal separation method to obtain an Ir @ H102 compound;
(2) ir @ H102-T catalyst preparation: transferring the Ir @ H102 compound obtained in the step (1) into a porcelain boat, and placing the porcelain boat into a constant-temperature air-blowing drying oven 60Drying at the temperature of the mixture overnight; then placing the mixture in a tube furnace, and introducing N2Gas, after the gas flow is stabilized, setting calcining temperature and heating program, and its heating rate is 5 deg.C/min-1Calcining for 2 hours after the set temperature T is reached; and naturally cooling to room temperature after the calcination is finished, taking out and grinding to obtain the composite nano catalyst, and recording the composite nano catalyst as Ir @ H102-T according to the calcination temperature.
4. The production method according to claim 3, wherein the calcination temperature set in the step (2) is 350 ℃.
5. Use of the nitroarene highly selective reduction catalyst Ir @ H102-T according to any one of claims 1 to 2 for the catalytic hydrogenation of nitroarenes.
6. The application of the nitroaromatic highly-selective reduction catalyst Ir @ H102-T prepared by the preparation method of any one of claims 3 to 4 in the catalytic hydrogenation of nitroaromatic.
7. Use according to claim 5 or 6, wherein the nitroarene is nitrobenzene, p-chloronitrobenzene, o-chloronitrobenzene, m-chloronitrobenzene, p-bromonitrobenzene, p-fluoronitrobenzene, p-nitrotoluene, o-nitrotoluene, m-nitrotoluene, p-ethylnitrobenzene, p-nitroacetophenone or p-nitrobenzyl alcohol.
8. The use according to claim 5 or 6, characterized in that it comprises in particular the following steps: adding a certain amount of nitroaromatic, a certain amount of solvent and a certain amount of Ir @ H102-T catalyst into an autoclave in sequence, wherein T is more than or equal to 350 and less than or equal to 400, and using H2After 5 times of air replacement, a certain H is maintained2Stirring and reacting for a certain time at a certain temperature under the pressure; filtering and recovering the catalyst, and removing the solvent from the filtrate by rotary evaporation to obtain the product.
9. Use according to claim 8, wherein the solvent is methanol, water, ethanol or isopropanol.
10. The use according to claim 9, wherein the dosage ratio of the nitroarene, the solvent and the catalyst is 1mmol/10mL/5-10 mg;
the use according to claim 8, characterized in that the catalytic hydrogenation step of nitroarenes is: at H2The pressure is 1.5MPa, the reaction is carried out for 30min under the temperature of 25-30 ℃ by stirring.
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