JP2010241691A - Method for hydrogen-reducing nitro compound in the presence of metal nano particle-carrying mcm-41 catalyst - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for hydrogen-reducing a nitro compound in the presence of a metal nano particle-carrying mesoporous silica catalyst such as MCM-41. <P>SOLUTION: This method for producing the amine compound includes hydrogen-reducing one of various nitro compounds in carbon dioxide as a medium in the presence of a metal nano particle-carrying mesoporous silica catalyst optimized in the case using the carbon dioxide as the medium in a low temperature condition in a temperature range of 0 to 200°C without using an injurious organic solvent, thus producing the amine compound. Hence, the new method for producing the amino compound for synthesizing the amine compound from the nitro compound in the safe carbon dioxide as a medium at low temperature in high efficiency in a low environmental load process enabling the reduction in wastes without using an organic medium can be provided. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing an amino compound by hydrogen reduction of a nitro compound using carbon dioxide as a reaction medium and metal nanoparticles having mesoporous silica as a support, and more particularly, liquefied carbon dioxide. Alternatively, supercritical carbon dioxide is used as a reaction medium, mesoporous silica having pores of 2 to 50 nm typified by MCM-41 is used as a support, and metal nanoparticles such as palladium, platinum, rhodium, iridium, and gold are used as the support. The present invention relates to a method for producing an amino compound, in which various amino compounds are produced by reducing a nitro compound using hydrogen and a catalyst that supports hydrogen.

  Due to recent critical economic problems and environmental problems associated with the increase in energy used, there is a growing interest in manufacturing technologies for various substances that are more environmentally friendly, more efficient, and save energy. In particular, competition in securing energy has intensified due to fluctuations in crude oil prices accompanying energy consumption by rapidly developing countries in several countries, and new material production technologies using lower-cost, energy-saving, and environmentally friendly processes. Development of is strongly desired.

  Among these substances, aniline is a typical compound as an amino compound, particularly an aromatic amine. This becomes a dye or pigment such as acetaminophen (aspirin) or aniline black, and further reacts with acetic anhydride to react with acetanilide or benzenesulfonic acid to become a raw material such as aniline benzenesulfonate, It is an important compound that is widely used as an intermediate and a raw material in the production of chemical products such as dyes and rubber, agricultural chemicals and pharmaceuticals. About 400,000 tons of these amino compounds are produced annually in Japan. In addition, aromatic amine compounds are used in various applications, and the annual production of these compounds is expected to be on the scale of 1 million tons.

  As a method for producing these amine compounds, a method for producing an amino compound by a hydrogen reduction reaction of a nitro compound is known as a typical production technique. The most typical example is a method for synthesizing aniline from nitrobenzene. Among them, the Bechampn reduction method using iron and acid, the catalytic hydrogenation method using nickel or copper as a catalyst, and the method of synthesizing under the pressure condition of ammonia in the presence of chlorobenzene and copper catalyst (Dow method) )and so on. In particular, various catalysts have been developed for catalytic hydrogenation to date, and in addition to nickel and copper catalysts, catalytic hydrogenation using transition metals with inorganic oxides such as silica and alumina as catalysts. Laws are being developed.

  For example, as a prior art, a production method for producing a high-purity aromatic amine while suppressing the accumulation of high-boiling impurities in the reactor and the accompanying decrease in catalyst activity and life, and this production method The first hydrogenation step of hydrogenating the aromatic nitro compound by reacting the aromatic nitro compound and hydrogen by gas-liquid contact with respect to the reaction apparatus for producing an aromatic amine, A second hydrogenation step of hydrogenating the unreacted aromatic nitro compound by reacting the unreacted aromatic nitro compound in the hydrogenation step with unreacted hydrogen in the gas phase. An amine production method and apparatus have been proposed (Patent Document 1).

  As another prior art, a simple and economical method for producing amines and working them up by distillation, which is carried out with a small amount of supply energy, is the hydrogenation of aromatic nitro compounds. A method has been proposed in which water is separated from a hydrogenated reaction mixture using at least a part of the heat generated by the hydrogenation in one column having an absolute overhead pressure of less than 1 bar (Patent Document). 2).

  As another prior art, in order to separate aniline by distillation before further use in subsequent steps, in the process for producing aniline, an aqueous alkali metal hydroxide solution is converted into crude aniline before and / or during distillation. A method of adding and purifying crude aniline has been proposed (Patent Document 3).

  As another prior art, aminodiphenylamines such as 4-aminodiphenylamine are reacted by reacting nitrohalogenated benzene with aniline in the presence of a base and a copper-phosphorus complex and then hydrogenating the intermediate formed nitrodiphenylamine. A method for producing (4-ADPA) has been proposed (Patent Document 4).

  As another prior art, in a method of producing an aromatic amine by reducing an aromatic nitro compound with an amine, the target product is obtained without using an expensive metal catalyst and without hydrogenolysis. A method for obtaining a high yield has been proposed (Patent Document 5).

  As described above, various methods have been proposed as prior arts. In particular, hydrogenation of aromatic nitro compounds is performed in a high-temperature gas stream, and is an exothermic reaction. Strict temperature control is required, such as the need to dissipate reaction heat, and optimization performance must always be maintained in terms of low environmental load and energy costs. Moreover, since aniline itself has a risk of a flammable explosion at 70 ° C. or higher in a humidified state, careful attention is required from the viewpoint of safety. Therefore, in this technical field, there has been a strong demand for the development of a new production technology for an amino compound that achieves high speed, high yield, and high selectivity and is environmentally friendly even under lower temperature conditions.

JP 2008-169205 A JP 2008-150377 A JP 2007-217416 A Japanese Patent Laid-Open No. 2004-210787 JP-A-9-31031

  In such a situation, in view of the prior art, the present inventors have made various studies on various reaction conditions, catalysts, production processes, etc., and as a result, used carbon dioxide as a medium. By using mesoporous silica that supports metal nanoparticles such as transition metals optimized when carbon dioxide is the main medium, it works as a highly active catalyst with almost no harmful organic medium. Based on these findings, we found that amine compounds can be produced in high yields and selectivities in a short time, and that they can be constructed as environmentally-friendly industrial production technologies. As a result of further research, the present invention has been completed.

  An object of the present invention is to provide a method for producing an amino compound from a nitro compound by a low environmental load type process. In addition, the present invention uses a metal nanoparticle catalyst having at least mesoporous silica composed of aluminum and silicon, oxygen and hydrogen as a carrier, uses almost no organic solvent, uses carbon dioxide as a main medium, and uses a nitro compound. It is an object of the present invention to provide a method for producing an amino compound that makes it possible to produce an amino compound with high conversion and high selectivity by reacting hydrogen with hydrogen.

The present invention for solving the above-described problems comprises the following technical means.
(1) A method for producing an amino compound from a nitro compound by a low environmental load type process, using a metal nanoparticle catalyst having at least mesoporous silica composed of aluminum, silicon, oxygen and hydrogen as a carrier, It is characterized by producing an amino compound by reducing the nitro group by reacting hydrogen with a nitro compound having at least one nitro group in the molecule, with carbon dioxide as the main medium with little use. A method for producing an amino compound.
(2) Using MCM-41 mesoporous silica as a carrier, using a catalyst made of palladium, platinum, rhodium or iridium having a particle size of 1 nm or more and 1 μm or less as metal nanoparticles, and using carbon dioxide as a medium, The method for producing an amino compound according to (1) above, wherein liquid carbon dioxide or supercritical carbon dioxide in which the pressure is in the range of normal pressure to 50 MPa or less and the temperature is in the range of room temperature (25 ° C.) to 100 ° C. .
(3) The amino compound is produced by reducing the nitro compound at a high yield and high selectivity by setting the partial pressure of hydrogen within the range of 0.1 MPa or more and less than 5 MPa. The manufacturing method of the amino compound as described in).
(4) The amino compound production method according to any one of (1) to (3), wherein the reaction time for hydrogenation is 1 second or more and less than 48 hours.
(5) The method for producing an amino compound according to any one of (1) to (3), wherein the production method is a batch type or a flow type.
(6) The method for producing an amine compound according to any one of (1) to (5), wherein the nitro compound is nitrobenzene, nitrotoluene, nitrobenzoic acid, or a derivative compound thereof.

Next, the present invention will be described in more detail.
The present invention uses as a catalyst metal nanoparticles having at least mesoporous silica composed of aluminum, silicon, oxygen and hydrogen as a catalyst, and uses carbon dioxide as a main medium with almost no organic solvent. The present invention relates to a method for producing an amino compound by reducing a nitro group by reacting a nitro compound having a nitro group with hydrogen.

  In the present invention, MCM-41 mesoporous silica is used as a support, a catalyst composed of palladium, platinum, rhodium, or iridium having a particle size of 1 nm or more and 1 μm or less is used as metal nanoparticles, and carbon dioxide is used as a medium. The use of liquid carbon dioxide or supercritical carbon dioxide in which the pressure is in the range of normal pressure to 50 MPa or less and the temperature is in the range of room temperature (25 ° C.) to 100 ° C. is a preferred embodiment.

  Mesoporous silica is an inorganic oxide having pores composed of at least aluminum, silicon, oxygen, and hydrogen. In the present invention, the target compound can be produced even if it contains no elements other than Si and O, but in order to obtain a more suitable production method, Al, P, Ti, Zr, and S are added to the catalyst surface. In order to obtain a more suitable production method, it is preferable to contain Al and P.

  In addition, vanadium, chromium, manganese, iron, nickel, copper, niobium, molybdenum, ruthenium, rhodium, palladium, silver, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, etc. Preferably, nickel, palladium, platinum, rhodium, and ruthenium nanoparticles are used, and most preferably, palladium and platinum nanoparticles are used.

  Further, the size of the metal nanoparticles is preferably 1 μm or less, preferably 1 nm or more and 1 μm or less, more preferably 1 nm or more and 100 nm or less, most preferably 1 nm or more and 50 nm or less. It is desirable to use it. In the present invention, it is almost unnecessary to use an organic solvent, but a general organic solvent can also be used as appropriate. In that case, carbon dioxide is required to be used as a main medium, and in the present invention, it is referred to as a main medium.

  In the method of the present invention, the reaction conditions are a temperature range of 0 ° C. or more and 200 ° C. or less, preferably a temperature range of 25 ° C. or more and 100 ° C. or less at room temperature. As for the reaction pressure, the partial pressure of carbon dioxide is normal pressure or higher, preferably 0.1 MPa or higher and 50 MPa or lower, and the hydrogen partial pressure is preferably 0.1 MPa or higher and 10 MPa or lower. In this case, other gas such as nitrogen, helium, neon, argon, and krypton can be mixed as appropriate as long as the partial pressures of carbon dioxide and hydrogen are above these conditions.

  In the method of the present invention, the reaction time is preferably within 48 hours, more preferably within 24 hours, and even more preferably within 1 hour. In the present invention, the reaction time can be arbitrarily set in consideration of the conversion rate, selectivity, yield, etc. of the target compound, depending on the substrate, the type of reaction system, temperature, and pressure conditions. . The concentration of the substrate can be appropriately adjusted in the range of 0.001% to 50%. In addition, in the method of the present invention, the yield can be improved by arbitrarily adjusting the acidity of the catalyst surface. Can be applied.

  The nitro compound that can be used as a substrate in the method of the present invention is a compound having at least one nitro group in the molecule and represented by the following general formulas 1 to 4, and the compound and hydrogen Can be reacted to reduce the nitro group to produce the corresponding amino compound.

In the above formulae, R _{1 to} R ₅ may be the same group, different groups or linked cyclic groups, and each represents hydrogen, an unsubstituted or substituted aryl group, or an unsubstituted or substituted group. It represents an alkyl group having 1 to 15 carbon atoms, an alkenyl group, an alkynyl group or a cycloalkyl group, or a halogen, an aldehyde, a ketone, a nitro group, an amino group, a sulfonic acid, an alcohol, or a thiol.

However, in the above formula, R _{6 to} R _{13 each} have at least one nitro group, and the other substituents may be the same group, different groups or linked cyclic groups, hydrogen, X (X is halogen), a nitro group, an alkyl group having 1 to 15 carbon atoms having a substituent, an alkenyl group having 1 to 15 carbon atoms having a substituent, an alkynyl group having 1 to 15 carbon atoms having a substituent, substitution And a cycloalkyl group having a group, a hydroxyl group, a halogen, an aldehyde, a ketone, a carboxylic acid, an amino group, an amide group, a sulfonic acid, a sulfonyl group, an alcohol, an ether, a thiol, and a thioether.

However, in the above formula, R _{6 to} R ₁₀ have at least one nitro group, and the other substituents may be the same group, different groups or linked cyclic groups, and may be hydrogen, halogen, An unsubstituted or substituted aryl group, or an unsubstituted or substituted alkyl group having 1 to 15 carbon atoms, an alkenyl group, an alkynyl group or a cycloalkyl group, or a halogen, aldehyde, ketone, nitro group, amino group , Sulfonic acid, trifluoromethanesulfonyl group, alcohol, thiol.

However, in the formula, R _{19 to} R _{22 each} have at least one nitro group, and the other substituents may be the same group, different groups or linked cyclic groups, and may be hydrogen, X ( X is halogen), a nitro group, an alkyl group having 1 to 15 carbon atoms having a substituent, an alkenyl group having 1 to 15 carbon atoms having a substituent, an alkynyl group having 1 to 15 carbon atoms having a substituent, and a substituent A cycloalkyl group, a hydroxyl group, a halogen, an aldehyde, a ketone, a carboxylic acid, an amino group, an amide group, a sulfonic acid, a sulfonyl group, an alcohol, an ether, a thiol, a thioether, and X is any one of NH, sulfur, and oxygen To express.

  More specifically, for example, the nitro compound is nitrobenzene, dinitrobenzene (including isomers), trinitrobenzene (including isomers), nitrotoluene (including isomers), dinitrotoluene (including isomers), TNT, or nitroanisole. (Including isomers), dinitroanisole (including isomers), trinitroanisole (including isomers), nitrobenzoic acid (including isomers), dinitrobenzoic acid (including isomers), nitrohalogenobenzene (including isomers, halogens) = Fluorine, chloro, bromine, iodine), nitrodihalogenobenzene (including isomers), nitrotrihalogenobenzene (including isomers, halogen = fluorine, chloro, bromine, iodine), halogenodinitrophenol (including isomers), dinitro Phenol (including isomers), 1,3,5-trinitropheno , Diazonitrobenzene, nitroglycol, nitroglycerin, nitrocellulose, nitroparaffin, nitromethane, nitroethane, nitropropane (including isomers), sodium nitroguay alcohol, nitrotoluidine, nitrotoluene (including isomers), nitrophenol (including isomers) , Sodium nitrobenzenesulfonate, methylnitroaniline (including isomers), methylnitrobenzoic anhydride, halogenonitrobenzoic acid (including isomers, halogen = fluorine, chloro, bromine, iodine), nitrobenzoyl chloride (including isomers), Nitrohumic acid, nitronaphthalene (including isomers), dinitronaphthalene (including isomers), trinitronaphthalene (including isomers), tetranitronaphthalene (including isomers), nitropyridine (isomerism) ), Halogenonitropyridine (including isomers), dinitropyridine (including isomers), halogenodinitropyridine (including isomers), trinitropyridine, tetranitropyridine, nitrothiophene, dinitrothiophene, trinitrothiophene, tetranitrothiophene , Dinitrohalogenobenzene (including isomers), trinitrohalogenobenzene (including isomers), nitrouracil, nitrocarbonyl, nitrohalogenoaniline, dinitrohalogenoaniline, nitrocotton, nitrocobalamin, nitrophenylhydrazine, nitrobenzyl alcohol, nitro Examples thereof include compounds having a structure represented by benzaldehyde, dinitrobenzaldehyde, and trinitrobenzaldehyde. However, it is not limited to these

  In conventional methods, for example, raw materials are used at high temperatures and there is a risk of flammable explosion, organic solvents are used, catalysts are severely degraded, waste is high, and energy costs are unavoidable. Accompanied. On the other hand, the method of the present invention is a new method for producing an amine compound by hydrogen reduction of a nitro compound. 1) The reaction temperature is low (200 ° C. to 100 ° C. or less), 2) Safe carbon dioxide is used, and organic No solvent is used. 3) Although the reaction rate is low, the reaction rate can be nearly 100% within a maximum of 48 hours. 4) The yield and selectivity are close to 100%. It has characteristics such as efficiency, and is useful as a new technique for producing amino compounds by hydrogen reduction, which can surely solve the problems of conventional methods.

The present invention has the following effects.
(1) The target compound can be produced safely without using raw materials under conditions where there is a risk of flammable explosion at high temperatures.
(2) Since organic solvents are hardly used and carbon dioxide is used as the main medium, there is almost no deterioration of the catalyst, the life is long, and the yield and selectivity are maintained high, thereby reducing waste. be able to.
(3) Since the reaction is fast in the low temperature range of 0 ° C. or higher and 200 ° C. or lower, the input energy can be reduced, and corrosion degradation of the manufacturing equipment can be suppressed. It is possible to provide an easy manufacturing method by an environmentally low load type process.

The XRD pattern of Pd-MCM-41 immediately after synthesis (a) and after calcination (b) is shown. The TRM image of Pd-MCM-41 after calcination is shown. The relationship between carbon dioxide pressure and conversion is shown. The reaction conditions are catalyst = 0.05 g, substrate = 1.0 g, reaction temperature = 50 ° C., reaction time = 10 minutes, hydrogen pressure = 2.0 MPa. The relationship between hydrogen pressure and conversion is shown. The reaction conditions are catalyst = 0.05 g, substrate = 1.0 g, reaction temperature = 50 ° C., reaction time = 10 minutes, carbon dioxide pressure = 10 MPa.

  EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited at all by these Examples.

(1) Synthesis of metal nanoparticle-supported mesoporous silica catalyst The metal nanoparticle-supported mesoporous silica catalyst was synthesized by the following procedure. Tetraethoxysilicate, palladium chloride, cetylmethylammonium bromide, sodium hydroxide and water were mixed at a molar ratio of 1.0: 0.01: 0.27: 0.34: 62.5, and the resulting gel was mixed. After filtration, it was dried and calcined in air at 550 ° C. for 10 hours. The obtained solid was pulverized in a mortar and measured by XRD (powder X-ray diffractometer), TEM (transmission electron microscope), and EPS (X-ray photoelectron spectroscopy), respectively, to confirm the structure. In the case of various metal nanoparticles, a metal nanoparticle-supported mesoporous silica catalyst was synthesized in the same manner, and the structure was confirmed.

(2) Synthesis of amino compound from nitro compound The metal nanoparticle-supported mesoporous silica catalyst (0.05 g) and the raw material nitrobenzene (1.0 g) were placed in a 50 mL stainless steel autoclave and capped. Thereafter, this is set in an oven, heated to a predetermined temperature (50 ° C.), hydrogen (2 MPa) is first introduced, carbon dioxide (10 MPa) is also immediately introduced, and the total pressure is set to a predetermined pressure ( 12 MPa).

  As a reaction, after adjusting the pressure, the reaction was carried out for 10 minutes with stirring. In order to complete the reaction, the solution was cooled at once in an ice bath and then slowly and carefully decompressed. About the obtained reaction mixture, after filtering a catalyst, it analyzed by GC-MS or CG, and obtained the identification of the product, the conversion rate, and the selectivity. As a result, the conversion rate was 100% and the product selectivity was 100%.

  The reaction time was 10 minutes, and under the same conditions as in Example 1, the partial pressure of carbon dioxide was changed from 6 MPa to 14 MPa, and the change in conversion rate was observed. The result is shown in FIG.

  FIG. 3 shows the results when the reaction conditions are as follows: catalyst = 0.05 g, substrate = 1.0 g, reaction temperature = 50 ° C., reaction time = 10 minutes, and hydrogen pressure = 2.0 MPa.

  Under the same conditions as in Example 1, the reaction time was 10 minutes, the partial pressure of carbon dioxide was 10 MPa, the hydrogen partial pressure was changed from 0.5 to 4 MPa, and the change in conversion was observed. The result is shown in FIG.

  FIG. 4 shows the results when the reaction conditions are as follows: catalyst = 0.05 g, substrate = 1.0 g, reaction temperature = 50 ° C., reaction time = 10 minutes, carbon dioxide pressure = 2.0 MPa.

  Various aromatic nitro compounds are used as substrates, the reaction is carried out under the same reaction conditions as in Example 1, the catalyst is filtered off, the resulting reaction mixture is analyzed by GC-MS or CG, and the product And the conversion and selectivity were determined. The results are shown in Table 1.

  As the catalyst, various metal nanoparticles (palladium, iridium, platinum, rhodium) are used, and each metal nanoparticle-supported mesoporous silica catalyst is used for the reaction under the same reaction conditions as in Example 1. The difference was examined. The results are shown in Table 2.

  As described above in detail, the present invention uses a harmful organic medium by using, as a catalyst, a metal nanoparticle-supported mesoporous silica catalyst that is optimized when carbon dioxide is used as a medium and carbon dioxide is used as a medium. Thus, it is possible to provide a method for producing an amine compound that makes it possible to produce an amine compound from various nitro compounds by hydrogen reduction. Since the present invention uses safe carbon dioxide as a medium, it is highly efficient and reduces waste in a low temperature condition of a temperature range of 0 ° C. or more and 200 ° C. or less without using an organic medium. This is an environmentally friendly new technology for producing amine compounds from nitro compounds, and is expected to be highly practical as an industrial production technology that can replace conventional methods.

Claims (6)

  A method of producing an amino compound from a nitro compound by a low environmental load process, using a metal nanoparticle catalyst supported by mesoporous silica composed of at least aluminum, silicon, oxygen and hydrogen, and using almost an organic solvent. In addition, an amino compound is produced by reducing a nitro group by reacting hydrogen with a nitro compound having at least one nitro group in the molecule, using carbon dioxide as a main medium. Production method.   MCM-41 mesoporous silica is used as a carrier, a catalyst made of palladium, platinum, rhodium, or iridium having a particle size of 1 nm or more and 1 μm or less is used as metal nanoparticles, and the pressure of carbon dioxide is usually used as a medium. The method for producing an amino compound according to claim 1, wherein liquid carbon dioxide or supercritical carbon dioxide having a pressure of 50 MPa or less and a temperature of room temperature (25 ° C.) or more and 100 ° C. or less is used.   The amino compound according to claim 1 or 2, wherein the amino compound is produced by reducing the nitro compound with high yield and high selectivity by setting the partial pressure of hydrogen to a range of 0.1 MPa or more and less than 5 MPa. Manufacturing method.   The method for producing an amino compound according to any one of claims 1 to 3, wherein the reaction time of hydrogenation is 1 second or more and less than 48 hours.   The manufacturing method of the amino compound in any one of Claim 1 to 3 whose manufacturing method is a batch type or a distribution type.   The method for producing an amine compound according to any one of claims 1 to 5, wherein the nitro compound is nitrobenzene, nitrotoluene, nitrobenzoic acid, or a derivative compound thereof.