JP4582992B2 - Method for producing alicyclic amine compound - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for stably producing a corresponding alicyclic amine compound, particularly cyclohexylamine, with high selectivity, high activity by amination of an alicyclic alcohol.
The resulting cyclohexylamines are useful compounds as intermediate materials for rubber chemicals, pharmaceuticals, artificial sweeteners, anticorrosives, surfactants, agricultural chemicals and the like.
[0002]
[Prior art]
As a method for producing cyclohexylamines, for example, (1) a method in which a reaction is carried out in a gas phase using copper oxide-zinc oxide as a catalyst in the presence of ammonia and hydrogen (“Industrial Chemical Journal”, 70 (9), (1508, 1967, Chemical Society of Japan), (2) A method in which a reaction is carried out in the presence of ammonia and hydrogen at normal pressure using a diatomaceous earth-supported reduced nickel shaped catalyst (Japanese Patent Publication No. 51-41627). (3) A method using a catalyst containing cobalt as a main component in a liquid phase under the conditions of high temperature and high pressure in the presence of ammonia and hydrogen (Japanese Patent Publication No. 51-32601), (4) And a method of carrying out amination in the presence of a treated ruthenium-based catalyst (JP-A-5-148191).
[0003]
[Problems to be solved by the invention]
However, in these known methods, for example, in the methods (1) and (2), there are many by-products of dicyclohexylamine, and the selectivity for the target compound, cyclohexylamine, is as low as about 70%. Further, there is a problem that the catalyst is rapidly deteriorated. Even in the method (3), the yield and selectivity of cyclohexylamine are not satisfactory, and the catalyst life is short. In the method (4), although the alumina-supported ruthenium catalyst pretreated with hydrogen is used, the selectivity of cyclohexylamine is relatively high and the catalyst life is improved. It is complicated. Moreover, although the selectivity shows 95% ± 1% in 2 to 20 repeated reactions, it cannot always be said that the selectivity is sufficient.
The present invention provides a method for producing an alicyclic amine compound from an alicyclic alcohol using a catalyst with high selectivity, high activity, and industrial stability, which solves the problems of the prior art. With the goal.
[0004]
[Means for Solving the Problems]
That is, the present invention relates to a carrier comprising a metal ruthenium as a main component having an average crystallite diameter of 10 nm or less as a catalyst, and an oxide or hydroxide of at least one metal selected from titanium, zirconium, and hafnium. in the presence of a supported ruthenium supported catalyst, a process for the preparation of a cycloaliphatic amine compounds you amination cycloaliphatic alcohols, those wherein ruthenium supported catalyst was obtained by a method of reducing the liquid phase by hydrogen in water It is a manufacturing method of the alicyclic amine compound which is.
[0005]
According to the method of the present invention, an alicyclic amine compound can be obtained with high selectivity and high activity, and high catalytic activity can be obtained for a long time without complicated operations such as catalyst activation treatment. It can be kept stable, and further, the selectivity of cyclohexylamine can be kept at 99% or more.
By using the catalyst of the present invention, not only the active species effective for the reaction can be formed, but also various alterations of the amination catalyst, for example, progress of aggregation over time, change in average crystallite diameter, support, etc. It is possible to remarkably suppress changes in reaction results due to chemical changes in the reaction.
[0006]
Hereinafter, the present invention will be described in detail.
The catalyst used in the present invention is an oxide or hydroxide of at least one metal selected from Group 4 of the Periodic Table, particles mainly composed of metal ruthenium having an average crystallite size of 10 nm or less. A ruthenium-supported catalyst supported on a support made of a product.
Examples of the metal belonging to Group 4 of the periodic table used as a carrier include titanium, zirconium, hafnium, and the like, and oxides or hydroxides of these metals are used. These composites can also be used. In particular, zirconium or hafnium oxides or hydroxides as the support give favorable results in the selectivity and yield of the alicyclic amine compounds. The form of these carriers is not limited, and the shape can be appropriately selected from the viewpoint of the handling property with respect to the reaction form. For example, in the case of the liquid phase suspension method, a carrier having a particle size of about 1 to 500 μm is usually preferable. The specific surface area of the carrier is also not limited and is usually ^{2 to} 300 m ² / g, preferably 5 to 150 m ² / g.
[0007]
The catalyst used in the present invention is a catalyst in which particles containing, as a main component, metal ruthenium having an average crystallite diameter of 10 nm or less are supported on a carrier. In general, it is empirically known that in a catalyst in which a metal is supported on a support, the catalytic activity per metal is enhanced due to the effect of dispersion of the metal due to the support, and the reaction selectivity or stability of the active metal substance is improved. ing. In addition, the metal fine particle crystal shows a specific size, form and surface structure depending on the surface properties of the precursor compound of the active species metal, the support metal oxide, the preparation method and conditions, etc., and the state of this metal becomes reactive. It is known to be greatly involved. Furthermore, when the active metal is highly dispersed on the support, it has been found that the reaction activity and reaction selectivity are improved due to the change in the adsorption characteristics of the reaction substrate caused by the interaction with the support.
[0008]
On the other hand, according to the study by the present inventors, the amination of the alicyclic alcohol depends on the state of the metal ruthenium supported on the oxide or hydroxide of at least one metal selected from Group 4 of the periodic table. It has been found that the reaction is influenced by this, and in particular, the selectivity and catalytic activity of cyclohexylamines, as well as the catalyst life, differ significantly. Based on this finding, the present inventors have conducted further research. As a result, when an alicyclic alcohol is aminated to produce an alicyclic amine compound, the average crystallite of particles mainly composed of ruthenium metal is used. It has been concluded that it is important that the diameter is 10 nm or less, preferably 8 nm or less. Here, the average crystallite diameter is calculated by the Scherrer's formula shown by the mathematical formula (1) from the broadening of the diffraction line width obtained by the X-ray diffractometry. When used as an X-ray source, it is calculated from the spread of diffraction lines derived from metal ruthenium crystallites having a maximum in the vicinity of 44 ° at the diffraction angle (2θ).
Dhkl = kλ / βcosθ (1)
Here, Dhkl is the crystallite size (Å), λ is the X-ray wavelength (Å), k is a proportional constant, β is the half-value width (radian) measured from the X-ray diffraction diagram, and θ is the diffraction angle. It is.
[0009]
By adopting the supported metal state as in the present invention, it is possible to obtain a catalyst that has both the physical effects of the supported catalyst and is extremely advantageous in the selectivity and activity of the amination reaction and further in the catalyst life. When the average crystallite diameter of metal ruthenium exceeds 10 nm, the reaction amount per ruthenium unit amount, that is, the productivity is lowered, and the selectivity, yield, and catalyst stability are lowered.
The reason why the catalyst of the present invention exerts an excellent effect on the amination reaction is not necessarily clear, but increases the interaction with the carrier due to the highly dispersed support, improves the stability of the metal ruthenium particles, and further amination From the improvement of the chemical stability of the support in the reaction field, it can be considered that active species effective for the selectivity, activity and catalyst life of cyclohexylamines are formed.
[0010]
As a method for preparing the catalyst in the present invention, a commonly used method for preparing a supported metal catalyst can be used. For example, using a solution in which a ruthenium compound as a precursor is dissolved in an appropriate solvent, a chemical wet method in which it is adsorbed on a carrier by a known impregnation method such as evaporation to dryness, adsorption method, dipping method, deposition method, spray method, etc. And chemical vapor phase method in which a ruthenium complex compound crystal is sublimated and directly subjected to a gas phase reaction with a carrier. Preferably, for example, a ruthenium compound is dissolved in a solvent to form a uniform solution, and a carrier is dispersed therein, and then a reagent that changes the ruthenium compound into a compound that does not dissolve in the solvent is introduced to deposit an insoluble ruthenium compound. The method of reducing is mentioned.
[0011]
Examples of the ruthenium compound include ruthenium halides, nitrates, hydroxides or oxides, complex compounds such as ruthenium carbonyl and ruthenium ammine complexes, and ruthenium alkoxides. As a solvent used when supporting the active component at the time of catalyst preparation, an organic solvent such as alcohol, acetone, tetrahydrofuran, hexane, toluene, etc. is used in addition to water.
As a specific preparation method, using a ruthenium chloride aqueous solution, using an alkali as an insolubilizing reagent, and depositing it on a carrier mainly in the form of ruthenium hydroxide, the method of reduction is easy to obtain the raw material, handling This is preferable from the viewpoint of convenience.
[0012]
Examples of the reduction method of the catalyst include a method of reducing with hydrogen in a gas phase or a liquid phase, a method of reducing with a reducing reagent such as formalin in the liquid phase, and the like, and a method of liquid phase reduction with hydrogen in water is preferable. In the case of reducing with hydrogen in water, it is preferably carried out under conditions of 100 to 250 ° C. and a hydrogen partial pressure of 1 to 200 kg / cm ² G.
On the other hand, in the method of vapor phase reduction with hydrogen using an adsorption method using a ruthenium chloride solution or an evaporation to dryness method, the crystallites during reduction are affected by not only ruthenium but also adsorbed chlorine. Depending on the reduction conditions, the crystallite size of the ruthenium particles may increase due to the significant sintering of ruthenium depending on the reduction conditions, so the preparation conditions are set in consideration of this point.
[0013]
The amount of metal ruthenium supported is preferably 0.1% to 20% by mass, more preferably 1 to 10% by mass, based on the carrier.
Examples of the alicyclic alcohol used in the present invention include C _{5 to} C ₁₀ cyclic alcohols such as cyclopentanol, cyclohexanol, cycloheptanol and cyclooctanol, and cyclohexanol is preferred. The purity of the raw material itself does not need to be particularly high, and may contain alicyclic paraffin, alicyclic olefin, lower paraffinic hydrocarbon, and the like.
[0014]
The amination reaction in the present invention can be carried out in a gas phase or a liquid phase in a fixed bed or a suspension bed in a continuous or batch manner, and it is particularly preferable to carry out the reaction under a liquid phase. When it is carried out in the liquid phase, the reaction can also be carried out in the presence of a solvent. The solvent used is not limited, but nitriles such as acetonitrile and propionitrile, aliphatic hydrocarbons such as normal hexane and cyclohexane, aromatic compounds such as benzene and toluene, ethers such as dioxane and diglyme, Water or the like can be used.
[0015]
When operating in the presence of a solvent, the concentration of cyclohexanol is usually from 1 to 95% by weight, preferably from 5 to 70% by weight. The reaction can be similarly performed when the reaction is performed in a gas phase, and these solvents may be vaporized in advance and supplied to the reactor.
In the present invention, the molar ratio of ammonia to cyclohexanol is usually 0.5 / 1 to 10/1, preferably 1/1 to 5/1.
In the present invention, the amination reaction is preferably carried out in the presence of hydrogen, and the molar ratio of hydrogen to cyclohexanol is usually 0.01 / 1 to 10/1, preferably 0.1 / 1 to 5/1. It is. The reaction pressure may be any of reduced pressure, normal pressure, and increased pressure. When the reaction is performed under increased pressure, it is usually in the range of 0.1 to 20 MPa, preferably 0.5 to 10 MPa, and the reaction temperature is usually , 50 to 300 ° C., preferably 80 to 250 ° C. The reaction time may be selected as appropriate by determining the selectivity of the target cyclohexylamines and the target value of the yield, and is not limited, but is usually several seconds to several hours.
[0016]
The amount of the catalyst varies depending on the type of catalyst used, and is not limited as long as the desired catalytic effect is obtained, but is usually 0.0001 / 1 to 100/1 in terms of mass ratio with respect to cyclohexanol, preferably Is in the range of 0.001 / 1 to 50/1.
When the reaction is carried out in the gas phase, the liquid hourly space velocity (LHSV) in the upflow or downflow reactor is preferably 0.01 to 10, more preferably 0.05 to The reaction is carried out under the condition of being in the range of 5.
[0017]
In the amination reaction in the present invention, although it varies depending on the catalyst species and reaction conditions, usually, in addition to the target product cyclohexylamine, as a by-product, a small amount of dicyclohexylamine, N-cyclohexylidenecyclohexylamine, cyclohexanone, etc. Generate. The produced cyclohexylamine is recovered from the reaction mixture in the reactor from which the catalyst has been separated by adding, for example, cyclohexane or benzene, azeotropic distillation, and then by distillation separation. If necessary, the desired purity can be achieved by further separation means.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Next, although an example and a comparative example explain the present invention concretely, the present invention is not limited to these examples.
[0019]
[Example 1]
(Catalyst preparation)
RuCl ₃ .3H ₂ O 1.3 g was dissolved in 300 ml of water to obtain a homogeneous solution of ruthenium chloride. 10 g of commercially available zirconium oxide powder was added thereto and dispersed under strong stirring. Next, 30 ml of a 1N NaOH aqueous solution was added, and stirring was continued for 2 hours as it was, so that an insoluble ruthenium compound mainly composed of Ru (OH) ₃ was deposited on zirconium oxide. This was washed several times with water and then dispersed again in 500 ml of water.
This dispersion was charged into a 1 L autoclave with an inner surface coated with Teflon (registered trademark), reduced to 160 kg at 60 ° C. with hydrogen at 60 kg / cm ² G for 24 hours, and this liquid was filtered under an argon atmosphere. And then dried at 80 ° C. under an argon atmosphere to obtain a 5% Ru / ZrO ₂ supported catalyst.
When the average crystallite diameter was calculated from the broadening of the line width of the X-ray diffraction pattern of this catalyst, the average crystallite diameter of metal ruthenium was 5.3 nm.
For confirmation, the catalyst obtained above was observed at a magnification of about 120,000 using a transmission electron microscope. As a result, the metal ruthenium particles (crystallites) having a size of 3 to 8 nm were singly or partially aggregated. It was confirmed that it was supported on the surface. Even in the agglomerated part, most individual crystallites could be distinguished.
[0020]
(Amination reaction)
Next, 1.4 g of the catalyst obtained above and 35 ml of water were charged into an inner volume 200 ml electromagnetic stirring autoclave coated with Teflon (registered trademark) on the inner surface, and the inside of the autoclave was replaced with nitrogen. The temperature was set at 180 ° C. with stirring. Next, 35 g of cyclohexanol was injected together with hydrogen to a total pressure of 50 kg / cm ² G (hydrogen charging pressure was 10 kg / cm ² G), and the reaction was performed for 1 hour while maintaining the reaction temperature at 180 ° C. with a stirring speed of 1000 rpm. .
After the reaction, the product was analyzed by gas chromatography. As a result, the cyclohexanol conversion was 62.2% and the cyclohexylamine selectivity was 99.7%. The by-product was dicyclohexylamine. The ammonia-based cyclohexylamine selectivity obtained by analyzing the amount of ammonia after the reaction by back titration was 99.5%.
This is clearly superior in the selectivity and activity of cyclohexylamine as compared to (1) to (4) described in the prior art. In addition, the amount of cyclohexylamine produced per ruthenium unit mass in this example is about 300 g / g-ruthenium · hour, and the activity per unit ruthenium mass is significantly larger than that in (4) described in the prior art. It is clear that there is an improvement.
[0021]
[Example 2]
The reaction was carried out in the same manner as in Example 1 except that the support at the time of catalyst preparation was hafnium oxide. As a result, the cyclohexanol conversion was 59.1%, and the cyclohexylamine selectivity was 99.2%. The by-product was dicyclohexylamine. The average crystallite diameter of the obtained 5% Ru / HfO ₂ metal ruthenium was 5.8 nm.
[0022]
[Example 3]
The reaction was performed in the same manner as in Example 1 except that titanium oxide was used as the support at the time of catalyst preparation. As a result, the cyclohexanol conversion rate was 45.0%, and the cyclohexylamine selectivity was 98.5%. The by-product was dicyclohexylamine. The average crystallite diameter of the obtained 5% Ru / TiO ₂ metal ruthenium was 6.3 nm.
[0023]
[Example 4]
An aqueous NaOH solution was added to the aqueous zirconium oxychloride solution, and the resulting white solid was filtered, washed with water until no chlorine ions were detected in the filtrate, and filtered to obtain zirconium hydroxide. The reaction was performed in the same manner as in Example 1 except that the zirconium hydroxide thus obtained was used as a carrier. As a result, the cyclohexanol conversion was 58.5%, and the cyclohexylamine selectivity was 99.2%. The by-product was dicyclohexylamine. The average crystallite diameter of the obtained 5% Ru / Zr (OH) ₂ metal ruthenium was 5.1 nm.
[0024]
[Example 5]
The reaction was performed in the same manner as in Example 1 except that the amount of ruthenium supported at the time of catalyst preparation was 10% and the amount of catalyst was 0.7 g. As a result, the cyclohexanol conversion was 59.1%, and the cyclohexylamine selectivity was 99.4%. The by-product was dicyclohexylamine. The average crystallite diameter of the obtained 10% Ru / ZrO ₂ metal ruthenium was 7.8 nm.
[0025]
[Example 6]
The reaction was carried out in the same manner as in Example 1 except that the amount of ruthenium supported at the time of catalyst preparation was 1% and the amount of catalyst was 7 g. As a result, the cyclohexanol conversion rate was 72.4%, and the cyclohexylamine selectivity was 99.2%. The by-product was dicyclohexylamine. The average crystallite diameter of the obtained 1% Ru / ZrO ₂ metal ruthenium was 4.1 nm.
[0026]
[Example 7]
In the reaction operation, the reaction was performed in the same manner as in Example 1 except that cyclohexanol was injected with nitrogen and the amination reaction was performed in a nitrogen atmosphere. As a result, the cyclohexanol conversion rate was 58.2%, and the cyclohexylamine selectivity was 98.7%. By-products were N-cyclohexylidenecyclohexylamine and cyclohexanone. The average crystallite diameter of the metal ruthenium of 5% Ru / ZrO ₂ used as the catalyst was 5.3 nm.
[0027]
[Example 8]
The amination reaction was repeated under the same conditions as in Example 1. As a result, no change was observed in the cyclohexanol conversion rate even in 1 to 10 repeated reactions, and the cyclohexylamine selectivity was maintained at 99% or more. Ammonia-based cyclohexylamine selectivity also maintained 99% ± 1% in 1 to 10 repeated reactions. The average crystallite diameter of 5% Ru / ZrO ₂ metal ruthenium which was subjected to 10 repetitive reactions was 5.4 nm. FIG. 1 shows the relationship between the number of reactions, the cyclohexanol conversion rate, and the cyclohexylamine selectivity. This is clearly superior in the selectivity and catalytic activity of cyclohexylamine compared to (4) described in the prior art.
[0028]
[Comparative Example 1]
The reaction was carried out in the same manner as in Example 1 except that the carrier at the time of catalyst preparation was alumina. As a result, the cyclohexanol conversion rate was 32.9%, and the cyclohexylamine selectivity was 97.1%. The by-product was dicyclohexylamine. The average crystallite diameter of the obtained 5% Ru / Al ₂ O ₃ metal ruthenium was 5.3 nm.
[0029]
[Comparative Example 2]
The reaction was carried out in the same manner as in Example 1 except that silica was used as the support at the time of catalyst preparation. As a result, the cyclohexanol conversion was 21.3% and the cyclohexylamine selectivity was 98.0%. The by-product was dicyclohexylamine.
The average crystallite diameter of the obtained 5% Ru / SiO ₂ metal ruthenium was 6.2 nm.
[0030]
[Comparative Example 3]
As a catalyst, N.I. The reaction was performed in the same manner as in Example 1 except that 5% Ru / Al ₂ O ₃ manufactured by E-Chemcat was used. As a result, the cyclohexanol conversion rate was 29.5%, and the cyclohexylamine selectivity was 97.5%. The average crystallite diameter of 5% Ru / Al ₂ O ₃ metal ruthenium was 5.9 nm.
[0031]
[Comparative Example 4]
2.6 g of RuCl ₃ .3H ₂ O was dissolved in 300 ml of water to obtain a homogeneous solution of ruthenium chloride. To this was added 10 g of the same zirconium oxide powder as used in Example 1 to prepare a dispersion, which was charged into a rotary evaporator, and water was evaporated to dryness while maintaining at 60 ° C. under reduced pressure. Next, this catalyst was reduced in a hydrogen stream at 400 ° C. for 3 hours to obtain a 10% Ru / ZrO ₂ catalyst. This preparation method is a commonly used technique. When the catalyst thus obtained was analyzed by powder X-ray diffraction, the average crystallite size of metal ruthenium was 11.5 nm.
[0032]
Next, the amination reaction of cyclohexanol was carried out in the same manner as in Example 1 except that 0.7 g of this catalyst was used. As a result, the cyclohexanol conversion was 16.5% and the cyclohexylamine selectivity was 98.7. %Met. The by-product was dicyclohexylamine.
[0033]
【The invention's effect】
By using the catalyst of the present invention, an alicyclic amine compound can be obtained from an alicyclic alcohol with high selectivity and high activity, and a stable catalyst system with significantly improved catalyst life is obtained. It is extremely valuable.
[Brief description of the drawings]
FIG. 1 is a graph showing the relationship between the number of reactions, cyclohexanol conversion rate, and cyclohexylamine selectivity.

Claims (5)

A ruthenium-supported catalyst in which particles mainly composed of metal ruthenium having an average crystallite diameter of 10 nm or less as a catalyst are supported on a support made of an oxide or hydroxide of at least one metal selected from titanium, zirconium, and hafnium. in the presence of a method for producing a cycloaliphatic amine compounds you amination cycloaliphatic alcohols, cycloaliphatic amines in which the ruthenium catalyst is obtained by the method of reducing the liquid phase by hydrogen in water Compound production method. The method for producing an alicyclic amine compound according to claim 1, wherein the amount of metal ruthenium supported is 1 to 10% by mass relative to the carrier. The method for producing an alicyclic amine compound according to claim 1, wherein the alicyclic alcohol is cyclohexanol. The method for producing an alicyclic amine compound according to claim 1, wherein the amination reaction is performed in a liquid phase. The method for producing an alicyclic amine compound according to claim 1, wherein the amination reaction is carried out in the presence of hydrogen.

Images