JP7089527B2 - Catalyst for nuclear hydrogenation reaction - Google Patents

Description

The present invention relates to a catalyst used in a nuclear hydrogenation reaction of an aromatic compound in which one or more amino groups are bonded to an aromatic ring.

Traditionally, nuclear hydrogenation reactions of aromatic compounds have been used to synthesize polyamide-imide resins and the like, which are raw materials for high-performance plastic products. A ruthenium catalyst is known as a catalyst used for a nuclear hydrogenation reaction of an aromatic compound.

For example, Patent Document 1 (Japanese Unexamined Patent Publication No. 2009-286747) efficiently contains N, N-dimethylcyclohexylamines useful as catalysts for producing polyurethane foam, epoxy curing agents, resist stripping agents, and corrosion inhibitors for steel. The cyclohexyl compound obtained by subjecting an aromatic compound to a nuclear hydrogenation reaction in the presence of a ruthenium catalyst or the like and hydrogen is used for the noble metal catalyst, formaldehyde derivative and hydrogen. A method for producing N, N-dimethylcyclohexylamines to be subjected to a reduction methylation reaction in the presence is disclosed (Patent Document 1, [Summary]).

More specifically, a ruthenium catalyst in which 5% of ruthenium is supported on an alumina (carrier) is disclosed (Patent Document 1, [0032] Example 1 and [0034] Example 2 and the like).

Japanese Unexamined Patent Publication No. 2009-286747

However, the present inventors have found that there is still room for improvement in the conventional ruthenium catalyst as described above from the viewpoint of further improving the conversion rate of the reactant in the nuclear hydrogenation reaction of the aromatic compound. ..

Therefore, the present invention has been made in view of such technical circumstances, and provides a catalyst for a nuclear hydrogenation reaction having a catalytic activity superior to that of a conventional ruthenium catalyst in a nuclear hydrogenation reaction of an aromatic compound. The purpose is to do.

The present inventors have focused on the state of ruthenium contained in the catalyst particles supported on the carrier in the ruthenium catalyst used for the nuclear hydrogenation reaction, and have diligently studied the configuration for further improving the catalytic activity. rice field.

As a result, the ratio of Ru (0 valence) Ru oxide to the ratio R _Ru in the analysis region near the surface of the ruthenium catalyst measured by X-ray photoelectron spectroscopy (XPS) is the ratio of R _RuOx . We have found that satisfying the following conditions is effective in improving the catalytic activity, and have completed the present invention.

More specifically, the present invention comprises the following technical matters.
That is, the present invention
A catalyst for a nuclear hydrogenation reaction used in a nuclear hydrogenation reaction for hydrogenating at least one of the π bonds of the aromatic ring of an aromatic compound having one or more amino groups bonded to the aromatic ring.
It contains a carrier and catalyst particles supported on the carrier.
The catalyst particles contain Ru (zero valence) and Ru oxide.
The ratio of Ru (0 valence) R _Ru (atom%) and the ratio of Ru oxide R _RuOx (atom%) in the analysis region near the surface measured by X-ray photoelectron spectroscopy (XPS) are as follows. Satisfying the condition of equation (1),
A catalyst for a nuclear hydrogenation reaction is provided.
0.60 ≤ {R _RuOx / (R _RuOx + R _Ru )} ≤ 0.90 ... Equation (1)

Here, in the present invention, the ratio of Ru (0 valence) R _Ru (atom%) and the ratio of Ru oxide R _RuOx (atom) in the analysis region near the surface of the nuclear hydrogenation reaction catalyst observed by XPS. %) Is a numerical value calculated under the condition that the total of these two components is 100%.

In the present invention, the value of R _RuOx / (R _RuOx + R _Ru ) represented by the above formula (1) is 0.60 or more and 0.90 or less, so that it can be used for the nuclear hydrogenation reaction of the present invention. The catalyst can exhibit better catalytic activity than the conventional ruthenium catalyst in the nuclear hydrogenation reaction of an aromatic compound in which one or more amino groups are bonded to an aromatic ring.

Although the detailed reason why the catalyst for nuclear hydrogenation reaction of the present invention has excellent catalytic activity has not been fully elucidated, the present inventors consider as follows.

That is, in the nuclear hydrogenation reaction catalyst having a structure satisfying the formula (1), the ratio of Ru oxide to Ru (0 valence) is higher than that of the conventional nuclear hydrogenation reaction catalyst. It is speculated that the activity against hydrogenation is improved.

Further, in the catalyst for nuclear hydrogenation reaction of the present invention, the Ru oxide contained in the catalyst particles may be in a state in which a hydroxyl group is bonded to a part thereof.

According to the present invention, there is provided a catalyst for nuclear hydrogenation reaction having a catalytic activity superior to that of a conventional ruthenium catalyst in the nuclear hydrogenation reaction of an aromatic compound in which one or more amino groups are bonded to an aromatic ring.

It is a schematic diagram which shows the schematic structure of the XPS apparatus for explaining the analysis condition of the X-ray photoelectron spectroscopy (XPS) in this invention.

<Catalyst for nuclear hydrogenation reaction>
Hereinafter, preferred embodiments of the catalyst for nuclear hydrogenation reaction of the present invention will be described in detail.
The hydrogenation catalyst of the present invention is used for a nuclear hydrogenation reaction in which at least one of the π bonds of the aromatic ring of an aromatic compound having one or more amino groups bonded to the aromatic ring is hydrogenated. ..

For example, the aromatic ring of the aromatic compound "4-tert-Butylaniline, reactant 1 in the following reaction formula (1)" represented by the following chemical reaction formula (1). It can be used in a nuclear hydrogenation reaction in which the π bond is hydrogenated and converted to "4-tert-Butylcyclohexylamine [(4-tert-Butylcyclohexylamine, product 2 in the following reaction equation (1)]".

The catalyst for nuclear hydrogenation reaction of the present invention may contain a carrier and catalyst particles supported on the carrier, and the form of supporting the catalyst particles is not particularly limited, and various structures are adopted. obtain.

(Carrier)
The carrier is not particularly limited as long as it can support the catalyst particles and has a relatively large surface area, but it may have good dispersibility in a solution containing the catalyst particles and may be inert. preferable.

As the inert carrier, for example, a carbon-based material (carbon), silica, alumina, Syrian carmina, magnesia and the like are preferable, and alumina is particularly preferable.
Further, for the above alumina carrier, the pore diameter PS determined by the BJH method is 8.00 nm to 12.00 nm, and the pore volume PV determined by the BJH method is 0.250 cm ³ / g to 0.400 cm ³ / g. Is preferable.

Here, in the present invention, the pore diameter PS is obtained from the desorption isotherm, which is the relationship between the relative pressure and the adsorption amount when the adsorbent (gas molecule) is desorbed from the solid surface by the BJH (Barrett, Joyner, Hallender) method. (BJH Desorption average pore diameter). Further, in the present invention, the pore volume PV is also a value obtained by the BJH method (BJH Desorption cumulative volume of pores between 1.7000 nm and 300.0000 nm diameter).

Examples of the carbon-based material include glassy carbon (GC), fine carbon, carbon black, graphite, carbon fiber, activated carbon, pulverized product of activated carbon, carbon nanofibers, carbon nanotubes and the like.

As the carbon-based material, conductive carbon is preferable, and as the conductive carbon, conductive carbon black is particularly preferable. Further, as the conductive carbon black, trade names such as "Ketjen Black EC300J", "Ketchen Black EC600", "Carbon EPC" and the like (manufactured by Lion Chemical Co., Ltd.) can be exemplified.

(Catalyst particles)
Next, in the present invention, the catalyst particles carried on the carrier contain Ru (zero valence) and Ru oxide, and are measured in the analysis region near the surface measured by X-ray photoelectron spectroscopy (XPS). , Ru (0 valence) ratio R _Ru (atom%) and Ru oxide ratio R _RuOx (atom%) satisfy the condition of the following formula (1).
0.60 ≤ {R _RuOx / (R _RuOx + R _Ru )} ≤ 0.90 ... Equation (1)

The amount of the catalyst particles supported on the carrier is not particularly limited as long as the effect of the present invention is not impaired, and depends on the reaction system and reaction conditions in which the catalyst for nuclear hydrogenation reaction of the present invention is adopted. It is set appropriately. Usually, it may be about 0.5 to 10 wt%.

The supported amount here means a value (rate) obtained by the formula: {mass of catalyst particles / (mass of catalyst particles + mass of carrier)} × 100. Here, the mass of the catalyst particles indicates the mass of the Ru component including Ru (0 valence) and Ru oxide contained in the catalyst particles.

The catalyst for nuclear hydrogenation reaction of the present invention has a configuration in which the value of {R _RuOx / (R _RuOx + R _Ru )} represented by the above formula (1) is 0.60 or more and 0.90 or less. Therefore, in the nuclear hydrogenation reaction of the aromatic compound, it is possible to exhibit a catalytic activity superior to that of the conventional ruthenium catalyst.

When the value of {R _RuOx / (R _RuOx + R _Ru )} is large, more Ru oxides are present in the vicinity of the surface of the catalyst particles for nuclear hydrogenation reaction as compared with Ru (0 valence), and this {R When the value of _RuOx / (R _RuOx + R _Ru )} is small, it means that Ru oxide is present in the vicinity of the surface of the catalyst particles for nuclear hydrogenation reaction in a smaller amount than Ru (0 valence).

If more Ru oxides are present in the vicinity of the surface of the catalyst particles for nuclear hydrogenation reaction of the present invention as compared with Ru (zero valence), the detailed mechanism has not been elucidated, but one or more aminos in the aromatic ring. There is a tendency to obtain the effect of improving the catalytic activity of the aromatic compound to which the group is bonded to the nuclear hydrogenation reaction.

On the contrary, when the amount of Ru oxide is less than that of Ru (zero valence) near the surface of the catalyst particles for nuclear hydrogenation reaction of the present invention, the aromatic compound in which one or more amino groups are bonded to the aromatic ring There is a tendency to obtain the effect of reducing the catalytic activity for the nuclear hydrogenation reaction.

In the present invention, these actions and effects are realized in a well-balanced manner by setting the value of R _RuOx / (R _RuOx + R _Ru ) represented by the above formula (1) to be 0.60 or more and 0.90 or less. It is something to do.

In the present invention, the Ru oxide contained in the catalyst particles may be in a state where a hydroxyl group is bonded to a part thereof.

In the present invention, the X-ray photoelectron spectroscopy (XPS) shall be carried out under the following analytical conditions (A1) to (A5).
(A1) X-ray source: Monochromatic AlKα
(A2) Photoelectron extraction accuracy: θ = 75 ° C
(A3) Charge correction: C1s peak energy is corrected as 284.8 eV (A4) Analysis area: 200 μm,
(A5) Chamber pressure during analysis: Approximately 1 × 10 ^-6 Pa

Here, in the photoelectron extraction probability θ of (A2), as shown in FIG. 1, X-rays emitted from the X-ray source 32 are irradiated to the sample set on the sample stage 34 and emitted from the sample. It is an angle θ when the photoelectron is received by the spectroscope 36. That is, the photoelectron extraction accuracy θ corresponds to the angle between the light receiving axis of the spectroscope 36 and the surface of the sample layer of the sample stage 34.

<Manufacturing method of catalyst for nuclear hydrogenation reaction>
The method for producing a catalyst for a nuclear hydrogenation reaction of the present invention is not particularly limited as long as it can support the catalyst particles on a carrier.

For example, an impregnation method in which a solution containing a Ru compound is brought into contact with a carrier to impregnate the carrier with a catalyst component, a liquid phase reduction method in which a reducing agent is added to a solution containing the catalyst component, an electrochemical precipitation method, and chemistry. A production method using a reduction method, a reduction precipitation method using adsorbed hydrogen, or the like can be exemplified.

However, the production conditions in the production of the catalyst for nuclear hydrogenation reaction are the ratio of Ru (0 valence) R _Ru (atom%) in the analysis region near the surface measured by X-ray photoelectron spectroscopy (XPS). It is necessary to adjust the synthetic reaction conditions in the manufacturing process so that the ratio of Ru oxide R _RuOx (atom%) satisfies the condition of the above-mentioned formula (1).

As a method for producing the catalyst for nuclear hydrogenation reaction of the present invention so as to satisfy the essential conditions represented by the above-mentioned formula (1), for example, a catalyst precursor obtained in each production step, finally. The chemical composition and structure of the obtained nuclear hydrogenation reaction catalyst are analyzed using various known analysis methods, and the obtained analysis results are fed back to each manufacturing process to select the raw materials to be selected, the blending ratio of the raw materials, and the selection. Examples thereof include a method of preparing and changing a synthesis reaction and reaction conditions (temperature, pressure of gas components, catalyst) of the synthesis reaction.

More specifically, for example, in the catalyst for nuclear hydrogenation reaction of the present invention, a water-soluble Ru salt is dissolved in water to generate Ru hydroxide, and the Ru hydroxide is used as a carrier (preferably alumina). It can be synthesized through a first step of synthesizing the carried catalyst precursor and a second step of heating and drying the catalyst precursor obtained in this first step in the air.

Then, the type of Ru salt in the first step, the amount (concentration) of Ru salt to be added to water, the pH of the aqueous solution in which the Ru salt is dissolved, the temperature of the aqueous solution, the temperature of the heating / drying treatment in the second step, and the treatment time are determined. By adjusting, the catalyst for nuclear hydrogenation reaction can be synthesized so as to satisfy the condition of the above-mentioned formula (1).

Further, a third step of reducing the catalyst obtained by obtaining the second step using a catalyst for nuclear hydrogenation reaction as a precursor and further using a reducing agent may be carried out as necessary. As a result, the ratio R _Ru (atom%) of Ru (0 valence) and the ratio R _RuOx (atom%) of Ru oxide are adjusted so as to more reliably satisfy the condition of the above-mentioned formula (1). can do. The type of reducing agent, the concentration of the reducing agent, the temperature of the reducing treatment in the third step, and the treatment time thereof can be adjusted. When carrying out the third step, vapor phase reduction in which hydrogen gas (reducing agent) is diluted with nitrogen gas may be preferably adopted.

Further, in the second step, the heating and drying treatments are sequentially performed two or more times, and the measurement by the X-ray photoelectron spectroscopy (XPS) is carried out in the interval, and the ratio of Ru (0 valence) is R _Ru (atom%). ) And the ratio of Ru oxide R _RuOx (atom%) may be confirmed.

Further, when the third step is carried out, the precursor obtained in the second step is measured by X-ray photoelectron spectroscopy (XPS), and the ratio of Ru (0 valence) is R _Ru (atom%) and Ru oxidation. After confirming the ratio of the substance R _RuOx (atom%), the reduction conditions in the third step may be appropriately adjusted. This makes it possible to more reliably synthesize a catalyst for nuclear hydrogenation reaction that satisfies the condition of the above-mentioned formula (1).

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

<< Example 1 >>
_The catalyst for nuclear hydrogenation reaction of the present invention (hereinafter _, "" The trade name "NECC-RA1" (manufactured by NE CHEMCAT) was manufactured as a catalyst for nuclear hydrogenation reaction 1).
Table 1 shows the {R _RuOx / (R _RuOx + R _Ru )} values of the catalyst for nuclear hydrogenation reaction.
The nuclear hydrogenation reaction catalyst 1 includes a first step of dissolving alumina and a water-soluble Ru salt in water to synthesize a catalyst precursor in which Ru hydroxide is supported on a carrier (alumina), and the first step thereof. The catalyst precursor obtained in one step was synthesized through a second step of heating and drying in air (treatment temperature: 80 ° C.).

<< Example 2 >>
The same as in Example 1 except that the value of {R _RuOx / (R _RuOx + R _Ru )} in the catalyst particles was changed to that shown in Table 1 for the nuclear hydrogenation reaction catalyst of Example 1. As a catalyst for the nuclear hydrogenation reaction of the present invention (hereinafter referred to as “catalyst 2 for nuclear hydrogenation reaction”) (trade name “NECC-RA2” (manufactured by NE CHEMCAT)) was produced.
The nuclear hydrogenation catalyst 2 is obtained by carrying out the first step and the second step under the same conditions as the nuclear hydrogenation reaction catalyst 1 of Example 1, and then obtaining the second step. A third step was carried out in which the reaction catalyst was used as a precursor and further reduced with a reducing agent. In the third step, the reduction treatment was carried out at 100 ° C. in a gas atmosphere of 90% nitrogen and 10% hydrogen.

<< Example 3 >>
The same as in Example 1 except that the value of {R _RuOx / (R _RuOx + R _Ru )} in the catalyst particles was changed to that shown in Table 1 for the nuclear hydrogenation reaction catalyst of Example 1. , The trade name "NECC-RA3" (manufactured by NE CHEMCAT) was produced as the catalyst for nuclear hydrogenation reaction of the present invention (hereinafter referred to as "catalyst 3 for hydrogenation reaction").
The nuclear hydrogenation catalyst 3 is obtained by carrying out the first step and the second step under the same conditions as the nuclear hydrogenation reaction catalyst 1 of Example 1, and then obtaining the second step. A third step was carried out in which the reaction catalyst was used as a precursor and further reduced with a reducing agent. In the third step, the reduction treatment was carried out at 150 ° C. in a gas atmosphere of 90% nitrogen and 10% hydrogen.

<< Comparative Example 1 >>
The catalyst 1 for comparative nuclear hydrogenation reaction of the present invention (Commodity) is the same as in Example 1 except that the value of {R _RuOx / (R _RuOx + R _Ru )} in the catalyst particles is changed to that shown in Table 1. The name "NECC-5E, manufactured by NECHEMCAT" was manufactured.

[Evaluation test]
Using the nuclear hydrogenation reaction catalysts obtained in Examples 1 to 3 and Comparative Example 1 above, the aromatic compound "4-terrary butylaniline [4-tert-" was used according to the following reaction formula (1). Butylaniline, hydrogenate the π bond of the aromatic ring of the following reaction formula (1) [(4-tert-Butylcyclohexylamine, the following reaction formula (1)). A nuclear hydrogenation reaction was carried out to convert to product 2] ”.
The reaction was carried out under the following reaction conditions. Solvent: isopropyl alcohol, concentration of reaction product 1: 1.6 mol%, hydrogen gas: 0.6 MPa, reaction temperature: 60 ° C., reaction time: 6 hours.

(1) Surface analysis of catalyst for nuclear hydrogenation reaction by X-ray photoelectron spectroscopy (XPS) Surface analysis by XPS was performed on the catalysts for nuclear hydrogenation reaction of Examples 1 to 3 and Comparative Example 1. Then, the ratio R _Ru (atom%) of Ru (0 valence) and the ratio R _RuOx (atom%) of Ru oxide were measured, and the value of {R _RuOx / (R _RuOx + R _Ru )} was calculated. ..
Specifically, "Quantara SXM" (manufactured by ULVAC-PHI) was used as an XPS device, and the analysis was carried out under the following analysis conditions.
(A1) X-ray source: Monochromatic AlKα
(A2) Photoelectron extraction accuracy: θ = 75 ° C (see Fig. 1)
(A3) Charge correction: C1s peak energy is corrected as 284.8 eV (A4) Analysis area: 200 μm
(A5) Chamber pressure during analysis: Approximately 1 × 10 ^-6 Pa
(A6) Measurement depth (escape depth): Approximately 5 nm or less The analysis results are shown in Table 1. The ratio R _Ru (atom%) of Ru (0 valence) and the ratio R _RuOx (atom%) of Ru oxide were calculated to be 100% with these two components.

(2) Measurement of the loading rate of Ru (ICP analysis)
For the catalysts for nuclear hydrogenation reaction of Examples 1 and 2 and Comparative Example 1, the loading ratio (wt%) of the catalyst particles containing Ru (0 valence) and Ru oxide was measured by the following method. That is, the catalyst for nuclear hydrogenation reaction was immersed in aqua regia to dissolve the metal. Next, the insoluble component alumina was removed from aqua regia. Next, the aqua regia excluding alumina was subjected to ICP analysis.
For the nuclear hydrogenation reaction catalysts of Examples 1 to 3 and Comparative Example 1, the carrying ratio of Ru {the carrying ratio of Ru derived from the Ru component obtained by combining Ru (0 valence) and Ru oxide}) is 5 wt%. Met.

(3) Calculation of conversion rate and yield By measuring the content and content ratio of the reactant 1 and the product 2 in the mixed composition obtained after the reaction, the conversion rate (%) and the product of the reaction product 1 are measured. The yield of 2 was calculated, and the results are shown in Table 1.

From the results shown in Table 1, the catalysts of Examples 1 to 3 according to the present invention in which the value of {R _RuOx / (R _RuOx + R _Ru )} satisfies the condition of the above-mentioned formula (1) are Comparative Example 1. It was clarified that the conversion rate of the reaction product 1 and the yield of the product 2 were higher than those of the catalyst (conventional ruthenium catalyst). That is, it is clear that the catalyst for nuclear hydrogenation reaction of the present invention has better catalytic activity than the conventional ruthenium catalyst in the nuclear hydrogenation reaction of an aromatic compound in which one or more amino groups are bonded to an aromatic ring. became.

The catalyst for nuclear hydrogenation reaction of the present invention has excellent catalytic activity in the nuclear hydrogenation reaction of an aromatic compound in which one or more amino groups are bonded to an aromatic ring, and an excellent yield of a product can be obtained. can. Therefore, the present invention is a catalyst for nuclear hydrogenation reaction that can be applied to the synthesis of polyamide-imide resin and the like, which are raw materials for high-performance plastic products, and contributes to the development of various industries.

Claims (1)

A catalyst for a nuclear hydrogenation reaction used in a nuclear hydrogenation reaction for hydrogenating at least one of the π bonds of the aromatic ring of an aromatic compound having one or more amino groups bonded to the aromatic ring.
It contains a carrier and catalyst particles supported on the carrier.
The catalyst particles contain Ru (zero valence) and Ru oxide.
The ratio of Ru (0 valence) R _Ru (atom%) and the ratio of Ru oxide R _RuOx (atom%) in the analysis region near the surface measured by X-ray photoelectron spectroscopy (XPS) are as follows. Satisfying the condition of equation (1),
Catalyst for nuclear hydrogenation reaction.
0.60 ≤ {R _RuOx / (R _RuOx + R _Ru )} ≤ 0.90 ... Equation (1)

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