Reduction catalyst

Abstract

[Problem] To provide a reduction catalyst of which the catalytic activity is hardly reduced even in the presence of a poisonous substance. [Solution] This reduction catalyst comprises: a carrier containing at least one among titania, alumina, silica, ceria, zirconia, magnesia, and activated carbon; and at least one metal which is selected from among elements belonging to groups 8, 9, and 10 in the periodic table and is supported on the carrier.

Description

Reduction catalyst

[0001] This invention relates to a reduction catalyst used in the reduction reaction of compounds.

[0002] Traditionally, the reduction reaction of compounds has been an important reaction used, for example, in the synthesis of active ingredients in the manufacture of pharmaceuticals and agrochemicals. As catalysts used in such reduction reactions, catalysts using Pd (palladium), particularly Pd / C catalysts (palladium-carbon catalysts), have been widely used.

[0003] On the other hand, ammonia (NH₄) is a poisoning substance that reduces the catalytic activity of Pd. ３ Examples of such poisons include amine compounds and halogen compounds. Such poisons may be additives to catalytic reduction systems or may be generated as a result of the reduction of substituents within the system, and there have been reports that this can inhibit the progress of the desired reaction (see, for example, Non-Patent Documents 1 and 2).

[0004] Tatsuo Yamanaka, "Poisoning Phenomena of Hydrogenation Catalysts and Selective Hydrogenation," Journal of Synthetic Organic Chemistry, Japan, Vol. 14, No. 3, 1956. P. 125-136. Hirotaka Sajiki and Kosaku Hirota, "Development of Pd / C-ethylenediamine complex catalyst [Pd / C(en)] and its application to selective catalytic reduction," Journal of Synthetic Organic Chemistry, Japan, Vol. 59, No. 2, 2001. P. 109-120.

[0005] By the way, the inventors of this application have found a novel Pd / TiO2 catalyst useful for flow synthesis. ２ We developed a catalyst and filed a patent application (Japanese Patent Application No. 2022-116750) for it. ２ According to the catalyst, by appropriately controlling the crystal structure of the support and the particle size of the metal, it is possible to suppress the formation of nitroso compounds in the hydrogenation of aromatic halonitro compounds while suppressing the decrease in the selectivity of the halogenated aromatic amine of the target product caused by the progress of the halogen detachment reaction. On the other hand, in various reduction reactions including hydrogenation reactions, NH ３ A remaining challenge was that the desired reaction would not proceed if toxic substances such as these were present in the system.

[0006] To avoid a decrease in catalytic activity due to poisoning substances, possible measures include recovering the poisoning substances from the system or adding compounds that counteract the properties of the poisoning substances. However, such measures may complicate the apparatus and make it difficult to manage the operation of the apparatus and control the quality of the product (i.e., the target product).

[0007] Therefore, in the reduction reaction of compounds, a catalyst that is less affected by poisoning substances (i.e., less prone to a decrease in catalytic activity) is desired compared to a general Pd / C catalyst.

[0008] This invention was devised in view of the problems of the prior art, and its main objective is to provide a reduction catalyst that does not easily lose catalytic activity even in the presence of a toxic substance.

[0009] To solve the above problems, one aspect of the present invention provides a reduction catalyst used in the reduction reaction of compounds, comprising a carrier containing at least one of titania, alumina, silica, ceria, zirconia, magnesia, and activated carbon, and at least one metal supported on the carrier and selected from elements belonging to groups 8, 9, and 10 of the periodic table.

[0010] According to this embodiment, a reduction catalyst can be realized in which catalytic activity does not easily decrease even in the presence of a poisoning substance.

[0011] In the above embodiment, the reduction reaction may be the reduction reaction of a compound having a nitro group or a nitrile group.

[0012] According to this embodiment, the reduction reaction of compounds having a nitro group or a nitrile group can be stably promoted.

[0013] In the above embodiment, it is preferable that an amine compound is produced in the reduction reaction.

[0014] According to this embodiment, the reduction reaction that produces the amine compound can be stably promoted.

[0015] In the above embodiment, the reduction reaction may be a deprotection reaction by reduction of a protecting group contained in the compound.

[0016] According to this embodiment, the deprotection reaction by reduction of the protecting group can be stably promoted.

[0017] In the above embodiment, the metal may include at least one of palladium, rhodium, platinum, iridium, and ruthenium.

[0018] According to this embodiment, by using an appropriate supported metal, a reduction catalyst can be realized in which catalytic activity is less likely to decrease even in the presence of a poisoning substance.

[0019] In the above embodiment, the metal is palladium, and the chemical shift of the Pd 3d5 / 2 peak in the spectrum measured by X-ray photoelectron spectroscopy is a shift of 2.3 eV or more to the higher energy side relative to the Pd 3d5 / 2 peak in the spectrum of palladium foil, the value of PdO / (Pd+PdO) in the integrated intensity of the X-ray diffraction pattern obtained by X-ray diffraction is 0, and the average particle size of the palladium measured by CO pulse method is 9.1 nm or more.

[0020] According to this embodiment, when palladium is used as the supported metal, a reduction catalyst that can suppress the decrease in catalytic activity in the presence of a poisoning substance can be easily obtained based on appropriate properties.

[0021] In the above embodiment, the metal is rhodium, and the chemical shift of the Rh 3d5 / 2 peak in the spectrum measured by X-ray photoelectron spectroscopy is a shift of 1.3 eV or more to the higher energy side relative to the Rh 3d5 / 2 peak in the spectrum of rhodium foil, and the average particle size of the rhodium measured by transmission electron microscopy is less than 5.0 nm.

[0022] According to this embodiment, when rhodium is used as the supported metal, a reduction catalyst that can suppress the decrease in catalytic activity in the presence of a poisoning substance can be easily obtained based on appropriate properties.

[0023] In the above embodiment, the metal may be palladium and rhodium, or palladium and ruthenium.

[0024] According to this embodiment, by using an appropriate supported metal, a reduction catalyst can be realized in which catalytic activity is less likely to decrease even in the presence of a poisoning substance.

[0025] In the above embodiment, the metals are palladium and rhodium, and the chemical shift of the Pd 3d5 / 2 peak in the spectrum measured by X-ray photoelectron spectroscopy is shifted to a higher energy side of 0.9 eV or more relative to the Pd 3d5 / 2 peak in the spectrum of palladium foil, the value of PdO / (Pd+PdO) in the integrated intensity of the X-ray diffraction pattern obtained by X-ray diffraction is 0, and the palladium particle size calculated from the Scherrer formula is less than 5.0 nm.

[0026] According to this embodiment, when palladium and rhodium are used as the supporting metal, a reduction catalyst that can suppress the decrease in catalytic activity in the presence of a poisoning substance can be easily obtained based on appropriate properties.

[0027] In the above embodiment, the carrier and the metal supported thereon may be reduced at a predetermined temperature to form a catalyst.

[0028] According to this embodiment, a reduction catalyst capable of suppressing the decrease in catalytic activity in the presence of a poisoning substance can be easily obtained by performing a reduction treatment.

[0029] Thus, according to the present invention, it is possible to provide a reduction catalyst that does not easily decrease in catalytic activity even in the presence of a poisoning substance.

[0030] Overall diagram of a flow-type organic synthesis system that carries out a hydrogenation reaction using a reduction catalyst. Pd catalyst 1-16 and NH relative to the reference catalyst. ３ Scatter plot showing the effect of addition (rate of change in conversion rate and rate of change in selectivity) of NH for Pd catalyst 1-16 and reference catalyst. ３ Bar graph showing the effect of addition (changes in conversion rate and selectivity) of NH for Pd catalyst 1-16 and reference catalyst. ３ Bar graph showing the effect of addition (change in yield) of NH for Pd catalysts 1, 10, 17-20 and the reference catalyst. ３Scatter diagram showing the influence of addition (change rate of conversion and change rate of selectivity) for Pd catalysts 1, 10, 17 - 20, and the reference catalyst with respect to NH ３ Bar graph showing the influence of addition (change in conversion and selectivity) for Pd catalysts 1, 10, 17 - 20, and the reference catalyst with respect to NH ３ Bar graph showing the influence of addition (change in yield), graph showing the XPS spectrum for Pd catalysts 10, 16, and Pd Foil, graph showing the XRD pattern for Pd catalysts 10, 12, 16, and the reference catalyst TiO ２ For NH with respect to support catalysts 1 - 8 and the reference catalyst ３ Scatter diagram showing the influence of addition (change rate of conversion and change rate of selectivity) for TiO ２ For NH with respect to support catalysts 1 - 8 and the reference catalyst ３ Bar graph showing the influence of addition (change in conversion and selectivity) for TiO ２ For NH with respect to support catalysts 1 - 8 and the reference catalyst ３ Bar graph showing the influence of addition (change in yield) for Pt catalysts 1 - 8 and the reference catalyst with respect to NH ３ Scatter diagram showing the influence of addition (change rate of conversion and change rate of selectivity) for Pt catalysts 1 - 8 and the reference catalyst with respect to NH ３ Bar graph showing the influence of addition (change in conversion and selectivity) for Pt catalysts 1 - 8 and the reference catalyst with respect to NH ３ Bar graph showing the influence of addition (change in yield) for Rh catalysts 1 - 5 and the reference catalyst with respect to NH ３ Scatter diagram showing the influence of addition (change rate of conversion and change rate of selectivity) for Rh catalysts 1 - 5 and the reference catalyst with respect to NH ３ Bar graph showing the influence of addition (change in conversion and selectivity) for Rh catalysts 1 - 5 and the reference catalyst with respect to NH ３ Bar graph showing the influence of addition (change in yield) for Rh catalysts 1, 4, 6, 7, and the reference catalyst with respect to NH ３ Bar graph showing the influence of addition (change in conversion and selectivity) for Rh catalysts 1, 4, 6, 7, and the reference catalyst with respect to NH ３Bar graph showing the effect of addition (change in yield) Graph showing XPS spectra for Rh catalysts 4, 6, and 7 TEM images for Rh catalysts 1, 4, 6, and 7 Graph showing the particle size distribution of Rh in Rh catalysts 1, 4, 6, and 7 NH for bimetallic catalysts 1-4 and reference catalyst ３ Scatter plot showing the effect of addition (rate of change in conversion rate and rate of change in selectivity) of NH for bimetallic catalyst 1-4 and reference catalyst ３ Bar graph showing the effect of addition (changes in conversion rate and selectivity) of bimetallic catalysts 1-4 and reference catalysts NH ３ The bar graph shows the effect of addition (change in yield) for bimetallic catalysts 1, 5-9 and the reference catalyst, NH ３ Scatter plot showing the effect of addition (rate of change in conversion rate and rate of change in selectivity) for bimetallic catalysts 1, 5-9 and the reference catalyst, NH ３ The bar graph shows the effect of addition (changes in conversion rate and selectivity) for bimetallic catalysts 1, 5-9 and the reference catalyst, NH ３ Bar graph showing the effect of addition (change in yield) Graph showing XPS spectra for bimetal catalyst 7, Pd catalyst 10, and Pd Foil Graph showing XRD patterns for bimetal catalysts 7, 9, and Pd catalyst 10 NH for bimetal catalysts 1, 10-14, and reference catalyst ３ Scatter plot showing the effect of addition (rate of change in conversion rate and rate of change in selectivity) of NH for bimetal catalyst 1, 10-14, and reference catalyst. ３ Bar graph showing the effect of addition (changes in conversion rate and selectivity) of bimetal catalyst 1, 10-14, and reference catalyst NH ３ Bar graph showing the effect of addition (change in yield)

[0031] The reduction catalyst according to the embodiment will be described below with reference to the drawings. In the following description, the term "reduction catalyst" refers to the catalyst according to the present invention unless otherwise specified.

[0032] Reduction catalysts are used in the reduction reaction of compounds, such as titania (TiO2). ２ ), alumina (Al ２ O ３ ), silica (SiO ２ ), Celia (CeO ２ ), Zirconia (ZrO２ A support comprising at least one of the following: ), magnesia (MgO), and activated carbon, on which at least one metal selected from elements belonging to groups 8, 9, and 10 of the periodic table (hereinafter referred to as the supported metal) is supported.

[0033] As the supporting metal, at least one of palladium (Pd), rhodium (Rh), platinum (Pt), iridium (Ir), and ruthenium (Ru) can be used. However, the supporting metal is not limited to these and can be appropriately selected from elements belonging to groups 8, 9, and 10 of the periodic table. The supporting metal can be dispersed and supported on the outer surface of the support or on the inner surface of the pores of the support.

[0034] When palladium is used as the supporting metal, its properties can be evaluated, for example, by the spectrum measured by XPS (X-ray photoelectron spectroscopy), the XRD pattern obtained by XRD (X-ray diffraction), and the particle size of palladium measured by the CO pulse method. For a reduction catalyst, it is desirable that the chemical shift of the Pd 3d5 / 2 peak in the XPS spectrum shifts to a higher energy side of 2.3 eV or more relative to the Pd 3d5 / 2 peak in the spectrum of the palladium foil. Furthermore, for a reduction catalyst, it is desirable that the value of PdO / (Pd+PdO) in the integrated intensity of the XRD pattern be 0. In addition, for a reduction catalyst, it is desirable that the average particle size of palladium measured by the CO pulse method be 9.1 nm or larger.

[0035] When rhodium is used as the supporting metal, its properties can be evaluated, for example, by the spectrum measured by XPS and the rhodium particle size measured by TEM (transmission electron microscope). For reduction catalysts, it is desirable that the chemical shift of the Rh 3d5 / 2 peak in the XPS spectrum shifts to a higher energy side of 1.3 eV or more relative to the Rh 3d5 / 2 peak in the spectrum of the rhodium foil. Furthermore, for reduction catalysts, it is desirable that the average particle size of rhodium measured by TEM is less than 5.0 nm.

[0036] The reduction catalyst may be a bimetallic catalyst using two supported metals. In this case, for example, a combination of palladium and rhodium, or a combination of palladium and ruthenium can be used as the supported metals. When palladium and rhodium are used as the supported metals, the weight ratio of palladium to rhodium in the reduction catalyst should be 25 / 1 (wt% / wt%) or less. More preferably, the weight ratio of palladium to rhodium should be 5 / 1 (wt% / wt%) or less, and even more preferably, 1.7 / 1 (wt% / wt%) or less.

[0037] The reduction catalyst is suitable as a catalyst for the reduction reaction of compounds having a nitro group or a nitrile group. Furthermore, the reduction catalyst is suitable as a catalyst for reduction reactions that produce amine compounds. In addition, the reduction catalyst is suitable as a catalyst for deprotection reactions by reduction of protecting groups contained in compounds.

[0038] Next, we will describe a method for evaluating the catalytic activity (i.e., resistance to poisoning substances) of a reduction catalyst.

[0039] In this embodiment, the conversion rate and selectivity in the reduction reaction are used as indicators to evaluate the catalytic activity of the reduction catalyst. More specifically, the catalytic activity is evaluated based on the rate of change in the conversion rate of the reactants and the rate of change in the selectivity of the target product before and after the addition of the poisoned substance in the reduction reaction (i.e., when the poisoned substance is not added and when the poisoned substance is added).

[0040] Rate of change of the conversion rate of reactants (CR) ＣＯＮＶ ) is expressed by the following formula (1). CR ＣＯＮＶ = 1 - (C １ / C ０ ) ... (1) However, C ０ : Conversion rate of the reactants before the addition of the toxic substance C １ : Conversion rate of reactants after the addition of the toxic substance

[0041] Rate of change of the selectivity of the target product (CR) ＳＥＬ ) is expressed by the following equation (2). CR ＳＥＬ = 1 - (S ａ１ / S ａ０) ... (2) However, S ａ０ : Selectivity of the product before the addition of the toxic substance S ａ１ Selectivity of the product after adding the toxic substance.

[0042] Furthermore, in this embodiment, the hydrogenation of aromatic halonitro compounds will be described as one of the reduction reactions in which a reduction catalyst is used. The hydrogenation of aromatic halonitro compounds is represented by the following general formula (3).

[0043]

[0044] In formula (3), X represents fluorine, chlorine, bromine, or iodine. R represents a hydrogen atom, a hydroxyl group, a carboxyl group, a sulfo group, an alkyl group, an alkenyl group, an aralkyl group, an aryl group, an acyl group, an alloyl group, an alkoxy group, or an alkoxycarbonyl group.

[0045] In the following, as a specific example of the hydrogenation of aromatic halonitro compounds, the hydrogenation of 4-chloronitrobenzene (hereinafter sometimes referred to as 4-ClNB) will be explained. In the hydrogenation of 4-chloronitrobenzene (an example of a compound having a nitro group), as shown in the process of formula (4), hydrogen is added to 4-chloronitrobenzene as a starting material (i.e., a reactant), and the target product 4-chloroaniline (hereinafter sometimes referred to as 4-ClAN) is produced via the intermediates 4-chloronitrosobenzene and 4-chlorophenylhydroxylamine. At this time, if the halogen removal reaction in 4-chloroaniline (an example of an amine compound) proceeds, 4-chloroaniline becomes aniline (hereinafter sometimes referred to as AN). This excessive reaction reduces the selectivity of 4-chloroaniline.

[0046] On the other hand, nitrobenzene (hereinafter sometimes referred to as NB) can be produced by the dehalogenation of 4-chloronitrobenzene. When hydrogen is added to nitrobenzene, aniline is produced via nitrosobenzene and hydroxylamine as intermediates. However, in the hydrogenation reaction in this embodiment, only 4-chloronitrosobenzene was detected as an intermediate, and the detection of nitrosobenzene was negligible.

[0047]

[0048] The hydrogenation of 4-chloronitrobenzene can be carried out by batch, semi-batch, or flow (continuous) methods.

[0049] Furthermore, the compounds targeted in reduction reactions using a reduction catalyst are not limited to 4-chloronitrobenzene; they may also be compounds containing a nitrile group, such as benzonitrile. In addition, the reduction catalyst is not limited to the hydrogenation of 4-chloronitrobenzene; it can also be used in deprotection reactions by reducing protecting groups (such as Cbz, phthaloyl, tosyl, Fmoc, and Boc groups) contained in the compound.

[0050] Next, we will describe more specific examples regarding the evaluation of reduction catalysts and their catalytic activity.

[0051] [Flow-type Organic Synthesis System] Referring to Figure 1, an example of the configuration of a flow-type organic synthesis system 1 that carries out the hydrogenation reaction of 4-chloronitrobenzene using a reduction catalyst will be described.

[0052] The flow-type organic synthesis system 1 is equipped with a flow-type fixed-bed reactor 2 (hereinafter referred to as reactor 2) that carries out a gas-liquid-solid three-phase reaction using hydrogen as a gaseous raw material, 4-chloronitrobenzene as a liquid raw material, and a reducing catalyst as a solid catalyst. Organic solvents inert to the reaction (such as alcohols, ethers, and other aromatic hydrocarbons) can be used as the liquid raw material. However, if the aromatic halonitro compound to be hydrogenated is a liquid, the reaction can also be carried out without a solvent.

[0053] Reactor 2 is a known tubular reactor containing a catalyst layer 3 that includes a reduction catalyst. Reactor 2 reacts by flowing gaseous and liquid raw materials, which are continuously supplied from the inlet line L1, through the catalyst layer 3. Reactor 2 is also equipped with a tubular electric furnace 4 consisting of two independent blocks, and the reaction temperature (in this case, the temperature of the catalyst layer 3) can be adjusted by supplying heat as needed. As reactor 2, for example, not only a downflow reactor that flows the raw materials in the same direction as gravity, but also an upflow reactor that flows the raw materials in the opposite direction of gravity can be used. Furthermore, the means of supplying heat to reactor 2 is not limited to the electric furnace 4, but other known devices (for example, a heat exchanger or a ribbon heater) may be used.

[0054] The gaseous raw material is continuously supplied to the reactor 2 via the gaseous raw material supply line L2, which is connected to the inlet line L1. The inlet line L1 is also connected to the purge gas supply line L3, through which the purge gas flows. In the flow-type organic synthesis system 1, purging operations of equipment and piping within the system can be performed by supplying purge gas to the purge gas supply line L3 during maintenance, etc.

[0055] The liquid raw material is stored in the liquid raw material tank 11. The liquid raw material is supplied to the reactor 2 via the liquid raw material supply line L4 through the inlet line L1 by the liquid raw material pump 12, and is continuously supplied to the reactor 2 together with the gaseous raw material. A preheater / precooler 13 is also provided in the liquid raw material supply line L4. The temperature of the liquid raw material supplied to the reactor 2 is adjusted to a preset target range by heating or cooling with the preheater / precooler 13.

[0056] Although not shown in the diagram, for example, the liquid raw material tank 11 is a first raw material tank that contains raw materials that do not contain toxic substances, and a second raw material tank that contains toxic substances (e.g., NH ３The system includes a second raw material tank containing raw materials to which ) has been added. This makes it possible to selectively supply liquid raw materials to the liquid raw material supply line L4 from either the first raw material tank or the second raw material tank (i.e., it is possible to switch between the presence or absence of poisoning substances in reactor 2). For example, when supplying 0.1 mol / L of 4-ClNB / (TOL-IPA: toluene-isopropyl alcohol mixed solvent) as a liquid raw material from the second raw material tank, equimolar amounts of NH are added to the substrate. ３ It can be added as a toxic substance.

[0057] Furthermore, in reactor 2, reaction products mainly containing 4-chloroaniline are continuously discharged from outlet line L6. A heat exchanger 21 is provided at outlet line L6. The temperature of the reaction products discharged from reactor 2 is adjusted to a preset target range by heating or cooling with the heat exchanger 21.

[0058] The reaction products cooled by the heat exchanger 21 are supplied to the main drum 25, which acts as a gas-liquid separator connected downstream of the outlet line L6. In the main drum 25, the reaction products are separated into off-gas (i.e., residual gas) containing unreacted gaseous raw materials, and a recovered liquid containing the target product of the reaction.

[0059] The off-gas (i.e., gaseous components) separated in the main drum 25 is discharged via the off-gas transport line L7 (the first line of the residual gas transport line).

[0060] The recovered liquid from the main drum 25 is supplied to the product recovery drum 41 via the recovered liquid transport line L9. In the product recovery drum 41, any gases remaining in the recovered liquid are separated from the recovered liquid into gas and liquid form. This separated gas is discharged to the outside via the separated gas discharge line L10. The recovered liquid separated in the product recovery drum 41 (i.e., the target product) is recovered via the product recovery line L11.

[0061] In the flow-type organic synthesis system 1, the operator can appropriately sample the recovered liquid from the product recovery line L11 at predetermined timings and analyze it using a liquid chromatograph or gas chromatograph to identify and quantify the target product, such as 4-chloroaniline.

[0062] [Catalysts and their evaluation results] Below, we will describe a general catalyst used as a standard for evaluating catalytic activity (hereinafter referred to as the reference catalyst) and a catalyst whose catalytic activity was compared with that of the reference catalyst (hereinafter referred to as the catalyst under evaluation). Among the catalysts under evaluation, those in which superior catalytic activity was found compared to the reference catalyst correspond to the reduction catalyst according to the present invention.

[0063] {Reference Catalyst} As the reference catalyst, a commercially available Pd / C catalyst with a metal (Pd) load of 5% (5% Palladium on Activated Carbon, Degussa type E 106 R / W 5%Pd (wetted with ca.55% water) manufactured by Wako Pure Chemical Industries, Ltd.) was used. Hereafter, this reference catalyst will be referred to as 5%Pd / C as needed.

[0064] {Pd Catalysts} First, we will explain the catalysts under evaluation that use Pd as the supported metal (referred to as Pd catalysts). Pd catalysts 1 and 21 shown below each have Pd on multiple different supports (TiO ２ , ZrO ２ , CEO ２ , CEO ２ -ZrO ２ pHS-Al ２ O ３ , TiO ２ (Rutile), HBT, SiO ２ , MgO, La-Al ２ O ３ The catalyst is supported on CB (carbon beads: spherical activated carbon). Pd catalyst 1-21 includes catalysts with different concentrations of Pd. Furthermore, Pd catalyst 1-21 includes catalysts with different reduction treatments and reduction treatment temperatures.

[0065] ○Pd Catalyst 1 (5% Pd / TiO2) (Method of preparing the catalyst) 5g of commercially available titania for catalyst support (Sakai Chemical Industry Co., Ltd. CS-300S-12, crystal type: anatase 100%) that has been calcined at 500°C for 3 hours is weighed out, and a palladium nitrate aqueous solution [Pd(NO3)] is prepared so that the Pd load (palladium load) is 5 wt% as the starting value. ２ (aq) was impregnated with the catalyst, dried, and then calcined at 500°C for 3 hours to obtain Pd catalyst 1 (Pd-supported titania catalyst).

[0066] Furthermore, the Pd catalyst 2-21 shown below was prepared under the same preparation conditions as Pd catalyst 1, but with only the support material changed to obtain the desired catalyst. ２ Catalysts that have undergone reduction treatment in an airflow (reduction temperature xxx degrees Celsius) are denoted as Rxxx. For example, a catalyst treated at a reduction temperature of 300°C is denoted as R300. Pd Catalyst 2 (5%Pd / ZrO2) Pd Catalyst 3 (5%Pd / CeO2) Pd Catalyst 4 (5%Pd / CeO2-ZrO2) Pd Catalyst 5 (5%Pd / pHS-Al2O3) Pd Catalyst 6 (2%Pd / TiO2(Rutile)) Pd Catalyst 7 (5%Pd / HBT) Pd Catalyst 8 (5%Pd / SiO2) Pd Catalyst 9 (5%Pd / MgO_R300) Pd Catalyst 10 (5%Pd / TiO2_R300) Pd Catalyst 11 (5%Pd / La-Al2O3_R300) Pd Catalyst 12 (5%Pd / CB) Pd Catalyst 13 (5%Pd / CeO2_R300) Pd Catalyst 14 (5%Pd / ZrO2_R300) Pd catalyst 15 (5% Pd / pHS-Al2O3_R300) Pd catalyst 16 (5% Pd / CB_R300) Pd catalyst 17 (0.2% Pd / TiO2_R100) Pd catalyst 18 (0.2% Pd / TiO2_R150) Pd catalyst 19 (0.2% Pd / TiO2_R220) Pd catalyst 20 (0.2% Pd / TiO2_R300) Pd catalyst 21 (2.5% Pd / TiO2_R300)

[0067] {Evaluation Results of Pd Catalysts} Next, we will explain the evaluation results of the catalytic activity of Pd catalysts 1-21 used in the reduction reaction (in this case, hydrogenation of 4-ClNB) (however, for the evaluation results of the catalytic activity of Pd catalyst 21, please refer to Table 5 below).

[0068] Figure 2 shows NH relative to Pd catalyst 1-16 and reference catalyst. ３ This is a scatter plot showing the effects of addition (rate of change in conversion rate and rate of change in selectivity).

[0069] Figure 2 shows the rate of change in the selectivity of 4-ClAN (1-(C1 / C0)) and the rate of change in the selectivity of 4-ClAN (1-(S)) for the reduction reaction using the reference catalyst (5% Pd / C). a1 / S a0 The relationship between )) is presented as an evaluation criterion.

[0070] In the following, the rate of change in the conversion rate of 4-ClNB when using the reference catalyst is expressed as "CR of the reference catalyst". ＣＯＮＶ " (The same applies to other catalysts.) Also, the rate of change in the selectivity of 4-ClAN when using the reference catalyst is called "CR of the reference catalyst ＳＥＬ " (The same applies to other catalysts.) Here, the CR of the reference catalyst ＣＯＮＶ (See horizontal axis) is 0.35, and the CR of the reference catalyst ＳＥＬ (See vertical axis) is 0.85.

[0071] In this embodiment, for each catalyst, CR ＣＯＮＶ The value of the reference catalyst CR ＣＯＮＶ Less than the value of CR ＳＥＬ The value of the reference catalyst CR ＳＥＬ If the value is smaller than (for example, if it is located inside the target region enclosed by the dashed line in Figure 2), the catalyst has better catalytic activity than the reference catalyst in the presence of the poisoned substance (i.e., NH as the poisoned substance). ３ It is determined that it has resistance to CR. For example, in Figure 2, the points relating to the Pd catalyst to be evaluated (i.e., CR ＣＯＮＶ and CR ＳＥＬ If the value of is located within the target region (see the dotted line frame), the catalyst is judged to have superior catalytic activity compared to the reference catalyst.

[0072] Figure 2 shows the CR of Pd catalyst 1-16 ＣＯＮＶ and CR ＳＥＬ The relationships between them are shown. Within the target region, there are points related to the Pd catalyst 16 (5%Pd / CB_R300). CR of Pd catalyst 16ＣＯＮＶ is -0.01, and CR ＳＥＬ is 0.70.

[0073] Thus, Pd catalyst 16 was determined to have catalytic activity superior to that of the reference catalyst in the presence of NH ３ (i.e., the poisoning substance). On the other hand, for catalysts other than Pd catalyst 16, since they are located outside the target region, they were determined not to have catalytic activity superior to that of the reference catalyst (i.e., they do not have resistance to NH ３ as a poisoning substance).

[0074] FIG. 3 is a bar graph showing the influence (changes in selectivity and conversion rate) of the addition of NH ３ on Pd catalysts 1 - 16 and the reference catalyst. In the data for each catalyst, the left side is the data before the addition of NH ３ , and the right side is the data after adding 1 equivalent of NH ３ [[ID=ID=19]] to the reactants (the same applies to FIG. 4). At the top of FIG. 3, the contact time between the reactant (fluid) and the catalyst in the reduction reaction using each catalyst is shown respectively. FIG. 4 is a bar graph showing the influence (change in yield) of the addition of NH ３ on Pd catalysts 1 - 16 and the reference catalyst. In FIG. 4, for each catalyst, the change in conversion rate and the contact time similar to those in FIG. 3 are also shown respectively.

[0075] As shown in FIG. 3, in the reduction reactions using each of Pd catalysts 1 - 16 and the reference catalyst, due to the addition of NH ３ [[ID=ID=26]], the conversion rate of 4 - ClNB (refer to the right vertical axis) and the selectivity of 4 - ClAN (refer to the left vertical axis) generally tend to decrease regardless of the presence or absence of catalyst reduction. Regarding the yield of the product in the reduction reaction using those catalysts (refer to FIG. 4), it also generally tends to decrease due to the addition of NH ３ [[ID=ID=28]]. However, for Pd catalyst 12 and Pd catalyst 16, which differ in the presence or absence of reduction treatment (refer to the dashed - line frame in FIG. 3), it was found that in the reduced Pd catalyst 16, the conversion rate of 4 - ClNB does not decrease even when NH ３ [[ID=ID=30]] is added.

[0076] Next, TiO[[ID=ID=34]] ２The influence of the Pd concentration (wt%) and the reduction treatment temperature of the catalyst in the Pd catalyst using a carrier will be described.

[0077] Fig. 5 is a scatter diagram similar to Fig. 2, showing the influence of NH ３ addition (change rate of conversion and change rate of selectivity) for Pd catalysts 1, 10, 17 - 20, and the reference catalyst.

[0078] In the Pd catalyst, it has been found that when the Pd concentration decreases, the Pd particle size becomes smaller and the Pd is in a more highly dispersed state. However, as shown in Fig. 5, even when the Pd concentration is changed to 0.2 wt% (Pd catalysts 17 - 20), the same excellent catalytic activity as when the Pd concentration is 5 wt% (Pd catalysts 1, 10) cannot be obtained (that is, it is located outside the target region surrounded by the two-dot chain line in Fig. 5).

[0079] Fig. 6 is a bar graph similar to Fig. 3, showing the influence of NH3 addition (change in selectivity and conversion) for Pd catalysts 1, 10, 17 - 20, and the reference catalyst. Fig. 7 is a bar graph similar to Fig. 4, showing the influence of NH ３ addition (change in yield) for Pd catalysts 1, from 10, 17 - 20, and the reference catalyst.

[0080] As shown in Fig. 6, in the reduction reaction using each of Pd catalysts 1, 10, 17 - 20, and the reference catalyst, the addition of NH ３ causes the conversion rate of 4 - ClNB and the selectivity of 4 - ClAN to tend to decrease regardless of the Pd concentration or the presence or absence of catalyst reduction. The same is true for the yield of the product in the reduction reaction using each of Pd catalysts 1, 10, from 17 - 20, and the reference catalyst (see Fig. 7). From such results, in the Pd catalyst using TiO ２ as a carrier, it is considered that the interaction between the TiO ２ carrier and the Pd supported thereon (that is, SMSI: Strong Metal - Support Interaction) causes a decrease in the reaction active sites.

[0081] Next, the results of the characterization of Pd catalyst 16, which showed better catalytic activity than the reference catalyst, will be described.

[0082] Figure 8 is a graph showing the XPS spectra (i.e., spectra measured by X-ray photoelectron spectroscopy) for Pd catalysts 10 and 16, and Pd Foil (palladium foil).

[0083] As shown in Figure 8, for Pd catalyst 10 (5%Pd / TiO2_R300), the chemical shift of the Pd 3d5 / 2 peak in the XPS spectrum is 0.6 eV higher in energy than the Pd 3d5 / 2 peak in the Pd Foil spectrum. For Pd catalyst 16 (5%Pd / CB_R300), the chemical shift of the Pd 3d5 / 2 peak is 2.3 eV higher in energy than the Pd 3d5 / 2 peak in the Pd Foil spectrum.

[0084] These results indicate that Pd catalysts exhibiting superior catalytic activity compared to the reference catalyst are characterized by a chemical shift of the Pd 3d5 / 2 peak in the XPS spectrum that is shifted to a higher energy side of 2.3 eV or more relative to the Pd 3d5 / 2 peak in the Pd foil spectrum.

[0085] Figure 9 is a graph showing the XRD patterns (i.e., X-ray diffraction patterns obtained by X-ray diffraction) for Pd catalysts 10, 12, 16, and the reference catalyst.

[0086] In the XRD pattern shown in Figure 9, the peaks at 2θ = 34 deg and 42 deg (see downward-pointing black triangle (▼)) are attributed to PdO, and the peak at 40 deg (see downward-pointing white triangle (▽)) is attributed to Pd. In the unreduced Pd catalyst 12 (5% Pd / CB), the presence of PdO can be confirmed, but in the reduced Pd catalyst 16 (5% Pd / CB_R300), the PdO peak disappears, and the peak attributed to Pd appears more strongly.

[0087] To calculate the relative abundance of Pd and PdO for Pd catalysts 10, 12, 16, and the reference catalyst, PdO / (Pd+PdO) was calculated based on the integrated intensity in the XRD pattern. Table 1 shows the values ​​of Pd, PdO, and PdO / (Pd+PdO) based on the integrated intensity in the XRD pattern. In Table 1, for Pd catalyst 10 (5%Pd / TiO2_R300) and Pd catalyst 16 (5%Pd / CB_R300), PdO is absent, and only Pd can be observed.

[0088]

[0089] Table 2 summarizes the evaluation results for Pd catalysts 10, 12, 16, and the reference catalyst. More specifically, Table 2 shows the conversion rate of 4-ClNB (NH₄) for Pd catalysts 10, 12, 16, and the reference catalyst. ３ Before addition, selectivity of 4-ClAN (NH ３ Before addition, the conversion rate of 4-ClNB (NH ３ Selectivity of 4-ClAN (NH after addition) ３ After addition, the rate of change in conversion rate (CR) ＣＯＮＶ ), rate of change of selection rate (CR ＳＥＬ The following values ​​are shown: Pd particle size measured by CO pulse method, PdO / (Pd+PdO) value based on integrated intensity in the XRD pattern, and chemical shift value of the Pd 3d5 / 2 peak relative to Pd foil in the XPS spectrum.

[0090]

[0091] As shown in Table 2, the Pd particle diameters measured by the CO pulse method for the reference catalyst (5%Pd / C) and Pd catalyst 12 (5%Pd / CB), which exhibited inferior catalytic activity to the reference catalyst, were 4.8 nm and 7.6 nm, respectively. In contrast, for Pd catalyst 16 (5%Pd / CB_R300), which showed superior catalytic activity to the reference catalyst, the Pd particle diameter measured by the CO pulse method was 9.1 nm.

[0092] These results indicate that Pd catalysts exhibiting superior catalytic activity compared to the reference catalyst are characterized by a Pd particle size of 9.1 nm or greater, as measured by the CO pulse method.

[0093] {TiO ２ {Carrier catalyst} Next, TiO ２ The catalyst to be evaluated using (TiO ２ This is called a carrier catalyst.) The following is an explanation of TiO ２ The support catalysts 1-8 are composed of different metals, and TiO ２ Includes a catalyst supported on a carrier. TiO ２ In carrier catalysts 1-8, the supported metals (Pd, Pt, Rh, Ir, Ru) are all at a concentration of 5 wt%. ２ The carrier catalysts 1-8 include catalysts that differ from each other only in whether or not a catalyst reduction treatment is performed.

[0094] ○TiO ２ Support catalyst 1 (5% Pd / TiO2) TiO ２ The carrier catalyst 1 corresponds to the Pd catalyst 1 described above, and its preparation method and evaluation method are the same as those for the Pd catalyst 1 described above.

[0095] ○TiO ２ Support catalyst 2 (5%Pd / TiO2_R300) TiO ２ The carrier catalyst 2 corresponds to the Pd catalyst 10 described above, and its preparation method and evaluation method are the same as those for the Pd catalyst 10 described above.

[0096] ○TiO ２ Carrier Catalyst 3 (5% Pt / TiO2) (Method of preparing the catalyst) 5g of commercially available titania for catalyst carriers (Sakai Chemical Industry Co., Ltd. CS-300S-12, crystal form: anatase 100%) was calcined at 500°C for 3 hours and weighed out. Nitric acid Pt aqueous solution [Pt(NO3)] was prepared so that the Pt loading amount (platinum loading amount) was 5 wt%. ２ The material was impregnated with (aq), dried, and then calcined at 500°C for 3 hours to obtain TiO2 support catalyst 3.

[0097] Note that the following TiO ２ For carrier catalysts 4-8, the precursor solution was changed to nitric acid Rh, nitric acid Ru, or nitric acid Ir, and the other preparation conditions were the same as for TiO2 carrier catalyst 3. ２ Support catalyst 4 (5% Pt / TiO2_R300) TiO ２Support catalyst 5 (5% Rh / TiO2) TiO ２ Support catalyst 6 (5%Rh / TiO2_R300) TiO ２ Support catalyst 7 (5%Ru / TiO2_R300) TiO ２ Carrier catalyst 8 (5%Ir / TiO2_R300)

[0098] {TiO ２ Evaluation results of the support catalyst} Next, TiO used in the reduction reaction (in this case, hydrogenation of 4-ClNB) ２ The results of the evaluation of the catalytic activity of support catalysts 1-8 will be explained.

[0099] Figure 10 is a diagram similar to Figure 2, and TiO ２ NH for carrier catalyst 1-8 and reference catalyst ３ This is a scatter plot showing the effects of addition (rate of change in conversion rate and rate of change in selectivity).

[0100] Within the target region shown in Figure 10 (see the dotted line frame), there is TiO ２ The point relating to the carrier catalyst 3-8 is located here. ２ CR of carrier catalyst 3 ＣＯＮＶ 0.16, CR ＳＥＬ It is 0.04. TiO ２ CR of the carrier catalyst 4 ＣＯＮＶ is -0.82, CR ＳＥＬ It is 0.03. TiO ２ CR of the carrier catalyst 5 ＣＯＮＶ It is -0.76, CR ＳＥＬ It is 0.04. TiO ２ CR of the carrier catalyst 6 ＣＯＮＶ It is -0.35, CR ＳＥＬ It is 0.03. TiO ２ CR of carrier catalyst 7 ＣＯＮＶ is -0.17, CR ＳＥＬ It is 0.05. TiO ２ CR of carrier catalyst 8 ＣＯＮＶ 0.04, CR ＳＥＬ It is 0.04.

[0101] This means that TiO ２ The carrier catalyst 3-8 is NH ３In the presence of [unspecified element], it was determined to have superior catalytic activity compared to the reference catalyst. On the other hand, TiO ２ Regarding support catalysts 1 and 2, they were determined not to exhibit superior catalytic activity compared to the reference catalyst because they were located outside the target region.

[0102] In other words, to obtain catalytic activity superior to that of the standard catalyst, TiO2 is not subjected to reduction treatment. ２ In a carrier catalyst, TiO ２ Pt and Rh are preferred as the supported metals to be combined with the carrier, and reduced TiO ２ In the support catalyst, it is considered preferable to use Ir and Ru in addition to Pt and Rh.

[0103] Figure 11 is a diagram similar to Figure 3, and TiO ２ NH for carrier catalyst 1-8 and reference catalyst ３ This is a bar graph showing the effect of addition (changes in conversion rate and selectivity). Figure 12 is similar to Figure 4, and shows TiO ２ NH for carrier catalyst 1-8 and reference catalyst ３ This bar graph shows the effect of the addition (change in yield).

[0104] As shown in Figure 11 (see dashed box), when Pt and Rh are used as the supporting metal, TiO ２ In carrier catalyst 3-8, NH ３ The decrease in the selectivity of 4-ClAN due to the addition was significantly suppressed compared to the case of the reference catalyst. Also, TiO ２ In carrier catalysts 3 and 8, NH ３ The decrease in the conversion rate of 4-ClNB due to the addition was also suppressed compared to the case of the standard catalyst. Furthermore, TiO ２ In the support catalyst 4-7, the conversion rate of 4-ClNB is NH ３ The concentration increased after addition, and the yield of the product (see Figure 12) also increased. From these results, TiO ２ In the carrier catalyst 4-7, NH ３ It's possible that it's acting as a promoter rather than a toxic substance.

[0105] {Pt Catalyst} Next, we will describe the catalysts to be evaluated that use Pt as the supported metal (referred to as Pt catalysts). Pt catalysts 1-8 each have multiple different oxide supports (TiO ２ , C, pHS-Al ２ O ３ , ZrO ２ SiO ２ Al ２ O ３ The catalyst is supported on a material. Pt catalysts 1-8 include catalysts with different concentrations of supported Pt. Furthermore, Pt catalysts 1-8 include catalysts that differ from each other only in whether or not they have undergone a catalyst reduction treatment.

[0106] ○Pt catalyst 1 (5%Pt / TiO2) Pt catalyst 1 is the same as the TiO2 ２ This corresponds to the carrier catalyst 3, and its preparation method and evaluation method are as described above for TiO ２ This is similar to carrier catalyst 3.

[0107] The following Pt catalysts 2-8 were obtained by using an aqueous Pt nitrate solution as a precursor and supporting Pt on various carriers. Pt catalyst 2 (1% Pt / C) Pt catalyst 3 (5% Pt / pHS-Al ２ O3) Pt catalyst 4 (5%Pt / ZrO ２ ) Pt catalyst 5 (5%Pt / TiO2_R300) Pt catalyst 6 (5%Pt / SiO2_R300) Pt catalyst 7 (5%Pt / ZrO2_R300) Pt catalyst 8 (5%Pt / Al2O3_R300)

[0108] The Pt catalyst 5 is the TiO mentioned above. ２ This corresponds to the carrier catalyst 4, and its preparation method and evaluation method are as described above for TiO ２ This is similar to carrier catalyst 3.

[0109] {Evaluation Results of Pt Catalysts} Next, we will explain the evaluation results of the catalytic activity of Pt catalysts 1-8 used in the reduction reaction (in this case, hydrogenation of 4-ClNB).

[0110] Figure 13 is similar to Figure 2, and shows NH relative to Pt catalyst 1-8 and the reference catalyst. ３ This is a scatter plot showing the effects of addition (rate of change in conversion rate and rate of change in selectivity).

[0111] Within the target region shown in Figure 13 (see the dotted line frame), all points relating to Pt catalysts 1-8 are located. Here, the CR of Pt catalyst 1 ＣＯＮＶ 0.16, CR ＳＥＬ The CR of Pt catalyst 2 is 0.04. ＣＯＮＶ 0.00 and CR ＳＥＬ The CR of Pt catalyst 3 is 0.00. ＣＯＮＶ 0.04, CR ＳＥＬ The CR of Pt catalyst 4 is 0.02. ＣＯＮＶ is -0.51, CR ＳＥＬ The CR of Pt catalyst 5 is 0.08. ＣＯＮＶ is -0.82, CR ＳＥＬ The CR of Pt catalyst 6 is 0.03. ＣＯＮＶ It is -0.35, CR ＳＥＬ The CR of Pt catalyst 7 is 0.03. ＣＯＮＶ is -0.17, CR ＳＥＬ The CR of Pt catalyst 8 is 0.05. ＣＯＮＶ 0.04, CR ＳＥＬ It is 0.04.

[0112] As a result, Pt catalyst 1-8 is NH ３ In the presence of [the specified substance], it was determined to have superior catalytic activity compared to the reference catalyst. In other words, it is considered preferable to use Pt as the supporting metal in order to obtain superior catalytic activity compared to the reference catalyst. Furthermore, when Pt is used as the supporting metal, it exhibits superior catalytic activity compared to the reference catalyst, regardless of whether or not reduction treatment is performed.

[0113] Figure 14 is similar to Figure 3, and shows NH relative to Pt catalyst 1-8 and reference catalyst. ３ This is a bar graph showing the effect of addition (changes in conversion rate and selectivity). Figure 15 is similar to Figure 4, and shows NH in relation to Pt catalyst 1-8 and the reference catalyst. ３ This bar graph shows the effect of the addition (change in yield).

[0114] As shown in Figure 14, when Pt is used as the supported metal, NH ３Before and after addition, a high selectivity for 4-ClAN was maintained compared to the case of the reference catalyst. In other words, when Pt is used as the supported metal, it is thought that the dechlorination and overreduction shown in equation (4) above do not proceed. Furthermore, in Pt catalysts 4 and 5, the conversion rate of 4-ClNB was NH ３ The amount increased after addition, and the yield of the product (see Figure 15) also increased. From these results, it can be seen that with Pt catalysts 4 and 5, NH ３ It's possible that it's acting as a promoter rather than a toxic substance.

[0115] {Rh Catalysts} Next, we will explain the catalysts under evaluation that use Rh as the supported metal (referred to as Rh catalysts). Rh catalysts 1-7 each have Rh on multiple different oxide supports (TiO ２ , CEO ２ , ZrO ２ The catalyst is supported on a substrate. Rh catalysts 1-7 include those with and without catalyst reduction treatment and those with different reduction treatment temperatures.

[0116] ○Rh catalyst 1 (5%Rh / TiO2) Rh catalyst 1 is the same as TiO2 ２ This corresponds to the carrier catalyst 5, and its preparation method and evaluation method are as described above for TiO ２ This is similar to carrier catalyst 5.

[0117] Rh catalyst 2-7 was obtained by using an aqueous solution of nitric acid and Rh as the precursor solution, and by changing the support.

[0118] Rh catalyst 2 (5%Rh / CeO2) Rh catalyst 3 (5%Rh / ZrO2) Rh catalyst 4 (5%Rh / TiO2_R300) Rh catalyst 5 (5%Rh / ZrO2_R300) Rh catalyst 6 (5%Rh / TiO2_R500) Rh catalyst 7 (5%Rh / TiO2_R750)

[0119] The Rh catalyst 4 is the TiO mentioned above. ２ This corresponds to the carrier catalyst 6, and its preparation method and evaluation method are as described above for TiO ２ It is similar to the carrier catalyst 6.

[0120] {Evaluation Results of Rh Catalysts} Next, we will explain the evaluation results of the catalytic activity of Rh catalysts 1-7 used in the reduction reaction (in this case, hydrogenation of 4-ClNB).

[0121] Figure 16 is similar to Figure 2, and shows NH relative to Rh catalysts 1-5 and the reference catalyst. ３ This is a scatter plot showing the effects of addition (rate of change in conversion rate and rate of change in selectivity).

[0122] Within the target region shown in Figure 13 (see the dotted line frame), all points related to Rh catalysts 1-5 are located. Here, the CR of Rh catalyst 1 ＣＯＮＶ It is -0.76, CR ＳＥＬ It is 0.04. CR of Rh catalyst 2 ＣＯＮＶ is -0.38, CR ＳＥＬ It is 0.04. CR of Rh catalyst 3 ＣＯＮＶ It is -1.45, CR ＳＥＬ It is 0.01. The CR of Rh catalyst 4 ＣＯＮＶ It is -0.35, CR ＳＥＬ It is 0.03. CR of Rh catalyst 5 ＣＯＮＶ is -2.17, CR ＳＥＬ It is 0.03.

[0123] As a result, Rh catalyst 1-5 becomes NH ３ In the presence of [the specified element], it was determined to have superior catalytic activity compared to the reference catalyst. In other words, it is considered preferable to use Rh as the supporting metal to obtain superior catalytic activity compared to the reference catalyst. Furthermore, when Rh is used as the supporting metal, it exhibits superior catalytic activity compared to the reference catalyst regardless of whether or not a reduction treatment is performed or the temperature of the reduction treatment.

[0124] Figure 17 is similar to Figure 3, and shows NH relative to Rh catalysts 1-5 and the reference catalyst. ３ This is a bar graph showing the effect of addition (changes in conversion rate and selectivity). Figure 18 is similar to Figure 4, and shows the effect of NH on Rh catalysts 1-5 and the reference catalyst. ３ This bar graph shows the effect of the addition (change in yield).

[0125] As shown in Figure 17, when Rh is used as the supported metal, NH ３Before and after addition, a high selectivity for 4-ClAN was maintained compared to the case of the reference catalyst. In other words, when Rh is used as the supported metal, it is thought that the dechlorination and overreduction shown in equation (4) above do not proceed. Furthermore, in Rh catalysts 1-5, the conversion rate of 4-ClNB was NH ３ The concentration increased after addition, and the yield of the product (see Figure 18) also increased. From these results, it can be seen that with Rh catalysts 1-5, NH ３ It's possible that it's acting as a promoter rather than a toxic substance.

[0126] Next, TiO ２ The effect of the reduction treatment temperature on Rh catalysts 1, 4, 6, and 7, which use a support, was evaluated. Rh catalyst 1 was not subjected to reduction treatment (it is a so-called calcined product), and the reduction treatment temperatures for Rh catalysts 4, 6, and 7 were 300°C, 500°C, and 750°C, respectively.

[0127] Figure 19 is similar to Figure 3, showing Rh catalysts 1, 4, 6, and 7, and NH relative to the reference catalyst. ３ This is a bar graph showing the effect of addition (changes in conversion rate and selectivity). Figure 20 is similar to Figure 4, and shows the effects of NH on Rh catalysts 1, 4, 6, 7 and the reference catalyst. ３ This bar graph shows the effect of the addition (change in yield).

[0128] As shown in Figure 19, Rh catalysts 1, 4, 6, and 7 (no reduction treatment, reduction treatment temperature 300°C, reduction treatment temperature 500°C, and reduction treatment temperature 750°C, respectively) produced NH ３ Before and after addition, a high selectivity for 4-ClAN was maintained compared to the case of the reference catalyst. In Rh catalysts 1, 4, and 6, the conversion rate of 4-ClNB was NH ３ The amount increased after addition, and the yield of the product (see Figure 20) also increased. From these results, it can be seen that with Rh catalysts 1, 4, and 6, NH ３ It's possible that it's acting as a promoter rather than a toxic substance.

[0129] On the other hand, in the case of Rh catalyst 7 (reduction treatment temperature 750°C), the conversion rate of 4-ClNB and the yield of the product were higher compared to the case of the reference catalyst. ３The activity decreased significantly both before and after the addition. In other words, it was found that with the Rh catalyst, the catalytic activity decreases compared to the reference catalyst when reduction treatment is performed at temperatures above 750°C.

[0130] Next, we will describe the results of characterizing Rh catalysts 4, 6, and 7, each with different reduction treatment temperatures (300°C, 500°C, and 750°C, respectively).

[0131] Figure 21 is a graph showing the XPS spectra for Rh catalysts 4, 6, and 7, similar to the case in Figure 8.

[0132] As shown in Figure 21, the XPS spectrum confirms that the intensity of the Rh 3d5 / 2 peak increases with increasing reduction temperature of the catalyst. This is thought to be due to the reprecipitation of Rh particles on the support during calcination in the preparation of the Rh catalyst, and the increase in the particle size of Rh as the reduction temperature increases. Furthermore, in the XPS spectrum, the Rh 3d5 / 2 peak of Rh catalyst 7, whose catalytic activity has decreased, is close to the binding energy of metallic Rh. On the other hand, the Rh 3d5 / 2 peaks of Rh catalysts 4 and 6 show a chemical shift to higher energies as the reduction temperature decreases, compared to Rh catalyst 7.

[0133] For Rh catalyst 4, the chemical shift of the Rh3d5 / 2 peak is 1.3 eV higher in energy relative to the Rh 3d5 / 2 peak (306.2 eV) in the spectrum of the Rh foil. Similarly, for Rh catalyst 6, the shift is 2.1 eV higher in energy relative to the Rh foil.

[0134] These results indicate that Rh catalysts exhibiting superior catalytic activity compared to the reference catalyst are characterized by a chemical shift of the Rh 3d5 / 2 peak in the XPS spectrum that is shifted to a higher energy side of 1.3 eV or more relative to the Rh 3d5 / 2 peak in the Rh foil spectrum.

[0135] Figures 22(A)-(D) are TEM images for Rh catalysts 1, 4, 6, and 7, respectively. Figures 23(A)-(D) are graphs showing the particle size distribution of Rh in Rh catalysts 1, 4, 6, and 7, respectively.

[0136] As shown in Figures 22 and 23, in the Rh catalyst, the diameter of the Rh particles increases with increasing reduction temperature. This is because the reduction treatment reduces TiO ２ This is thought to be due to the reprecipitation of Rh from the support material and the fact that sintering becomes more likely as the reduction treatment temperature increases.

[0137] In measuring the particle size distribution of Rh, the lengths of 100 Rh particles were measured in several fields of view at different magnifications, based on the Japanese Industrial Standard (JIS H 7804:2005), and the length distribution and the length-average diameter (i.e., the average particle diameter of Rh) were calculated. The length-average diameters of Rh in Rh catalysts 1, 4, 6, and 7 were 2.9 nm, 3.0 nm, 3.9 nm, and 5.0 nm, respectively. Note that Rh is TiO2. ２ Due to its characteristic of eluting and reprecipitation on the support, evaluation by XRD is difficult, and considering the possibility of SMSI formation, particle size measurement by CO pulse method is unsuitable. Therefore, for the Rh catalyst, the particle size of Rh was determined by TEM observation.

[0138] The average length diameter of Rh in Rh catalyst 1, which was reduced at 300°C (2.9 nm), was approximately the same as that of Rh catalyst 4, which was calcined at 500°C (3.0 nm). This is thought to be due to the fact that the thermal histories of Rh catalysts 1 and 4 were almost identical.

[0139] These results indicate that Rh catalysts exhibiting superior catalytic activity compared to the reference catalyst are characterized by an average Rh particle size of less than 5.0 nm, as observed by TEM.

[0140] Table 3 summarizes the evaluation results for Rh catalysts 1, 4, 6, 7, and Rh Foil (rhodium foil). More specifically, Table 3 shows the conversion rate of 4-ClNB (NH) for each of Rh catalysts 1, 4, 6, 7, and Rh Foil. ３ Before addition, selectivity of 4-ClAN (NH３ Before addition, the conversion rate of 4-ClNB (NH ３ Selectivity of 4-ClAN (NH after addition) ３ After addition, the rate of change in conversion rate (CR) ＣＯＮＶ ), rate of change of selection rate (CR ＳＥＬ The Rh particle size (length-average diameter of Rh) measured by TEM observation, and the chemical shift value of the Rh 3d5 / 2 peak relative to the Rh foil in the XPS spectrum are shown.

[0141]

[0142] As shown in Table 3, Rh catalysts exhibiting superior catalytic activity compared to the reference catalyst are characterized in particular by a chemical shift of the Rh 3d5 / 2 peak in the XPS spectrum that is shifted to a higher energy side of 1.3 eV or more relative to the Rh3d5 / 2 peak in the Rh Foil spectrum, and by an average Rh particle size of less than 5.0 nm obtained by TEM observation.

[0143] {Bimetallic Catalyst} Next, we will explain the catalyst under evaluation (called a bimetallic catalyst) which uses two types of metals as the supported metal. A bimetallic catalyst is made by co-impregnating a support with Pd as the base metal and one of Rh, Ru, Pt, or Ir as the second metal. The support is TiO ２ , ZrO ２ pHS-Al ２ O ３ , HBT, and SiO ２ One of the following was used.

[0144] The bimetallic catalysts 1-14 described below are catalysts that use Pd and Rh, Pd and Ru, or Pd and Ir as supported metals. Bimetallic catalysts 1-14 include catalysts in which the same two metals are supported, but the ratio of the concentrations of those metals differs. Furthermore, bimetallic catalysts 1-14 include catalysts that differ in whether or not a catalyst reduction treatment is performed.

[0145] ○Bimetallic catalyst 1 (2.5%Pd-2.5%Rh / TiO2_R300) (Method of preparing the catalyst) 5g of commercially available titania for catalyst support (Sakai Chemical Industry Co., Ltd. CS-300S-12, crystal type: 100% anatase) was calcined at 500°C for 3 hours and weighed out. As the starting values, a nitrate Pd aqueous solution [Pd(NO3) 2.5 wt% was prepared so that the Pd loading amount (palladium loading amount) and Rh loading amount (rhodium loading amount) were each 2.5 wt%. ２ (aq)], Rh nitric acid aqueous solution [Rh(NO ３ ) ３ (aq) was co-impregnated, dried, and then calcined at 500°C for 3 hours to obtain bimetal catalyst 1.

[0146] The bimetallic catalyst 2-14 shown below was obtained by preparing it under the same conditions, but with variations in the precursor solution, loading amount, and support. Bimetallic catalyst 2 (2.5%Pd-2.5%Ru / TiO2_R300) Bimetallic catalyst 3 (2.5%Pd-4.5%Pt / TiO2_R300) Bimetallic catalyst 4 (2.5%Pd-4.4%Ir / TiO2_R300) Bimetallic catalyst 5 (2.5%Pd-1.5%Rh / TiO2_R300) Bimetallic catalyst 6 (2.5%Pd-0.5%Rh / TiO2_R300) Bimetallic catalyst 7 (2.5%Pd-0.1%Rh / TiO2_R300) Bimetallic catalyst 8 (2.5%Pd-0.025%Rh / TiO2_R300) Bimetallic catalyst 9 (2.5%Pd-0.1%Rh / TiO2) Bimetallic catalyst 10 (2.5%Pd-2.5%Rh / CeO2_R300) Bimetallic catalyst 11 (2.5%Pd-2.5%Rh / pHS-Al2O3_R300) Bimetallic catalyst 12 (2.5%Pd-2.5%Rh / ZrO2_R300) Bimetallic catalyst 13 (2.5%Pd-2.5%Rh / HBT_R300) Bimetallic catalyst 14 (2.5%Pd-2.5%Rh / SiO2_R300)

[0147] {Evaluation Results of Bimetallic Catalysts} Next, we will explain the evaluation results of the catalytic activity of bimetallic catalysts 1-14 used in the reduction reaction (in this case, hydrogenation of 4-ClNB).

[0148] Figure 24 is similar to Figure 2, and shows the bimetallic catalysts 1-4 and NH relative to the reference catalyst. ３ This is a scatter plot showing the effects of addition (rate of change in conversion rate and rate of change in selectivity). Bimetallic catalysts 1-4 use Rh, Ru, Pt, and Ir as supported metals in a molar ratio of 1:1 with respect to the base Pd.

[0149] Within the target region shown in Figure 24 (see the dotted line frame), points related to bimetallic catalysts 1 and 2 are located. Here, the CR of bimetallic catalyst 1 ＣＯＮＶ 0.00 and CR ＳＥＬ The value is 0.34. The CR of the bimetal catalyst 2 ＣＯＮＶ It is -0.75, CR ＳＥＬ It is 0.26.

[0150] As a result, the bimetallic catalysts 1 and 2 are NH ３ In the presence of [the specified element], it was determined that the catalyst exhibited superior catalytic activity compared to the reference catalyst. On the other hand, bimetallic catalysts 3 and 4 were located outside the target region and were therefore determined not to exhibit superior catalytic activity compared to the reference catalyst.

[0151] Figure 25 is similar to Figure 3, and shows the bimetallic catalysts 1-4 and NH relative to the reference catalyst. ３ This is a bar graph showing the effect of addition (changes in conversion rate and selectivity). Figure 26 is similar to Figure 4, and shows the effect of NH on bimetallic catalysts 1-4 and the reference catalyst. ３ This bar graph shows the effect of the addition (change in yield).

[0152] As shown in Figure 25, in the bimetal catalyst 1-4, NH ３ The decrease in the selectivity of 4-ClAN due to the addition was suppressed compared to the case of the reference catalyst. In bimetal catalyst 1, NH ３ The decrease in the conversion rate of 4-ClNB due to the addition was also suppressed compared to the case of the standard catalyst. Furthermore, in the bimetal catalyst 2, the conversion rate of 4-ClNB was NH ３ The amount increased after addition, and the yield of the product (see Figure 26) also increased. From these results, it can be seen that with bimetal catalyst 2, NH ３ It's possible that it's acting as a promoter rather than a toxic substance.

[0153] Next, we will explain the effect of the ratio of the concentrations (wt%) of the two metals in a bimetallic catalyst.

[0154] Figure 27 is similar to Figure 2, and shows NH to bimetallic catalysts 1, 5-9 and the reference catalyst. ３ This is a scatter plot showing the effects of addition (rate of change in conversion rate and rate of change in selectivity). Bimetallic catalysts 1 and 5-9 are catalysts in which the ratio of the concentration of Rh to the base Pd as the supported metal differs. More specifically, the Pd:Rh (wt%) ratios for bimetallic catalysts 1 and 5-9 are 2.5:2.5, 2.5:1.5, 2.5:0.5, 2.5:0.1, and 2.5:0.025, respectively.

[0155] Within the target region shown in Figure 27 (see the dotted line frame), the points related to bimetallic catalysts 1 and 6, 7, as shown in Figure 24, are located. Here, the CR of bimetallic catalyst 6 ＣＯＮＶ 0.32, CR ＳＥＬ The CR of the bimetallic catalyst 7 is 0.42. ＣＯＮＶ 0.23, CR ＳＥＬ It is 0.49.

[0156] Based on these results, it was determined that bimetallic catalysts 1, 6, and 7 possess superior catalytic activity compared to the reference catalyst.

[0157] Furthermore, bimetallic catalyst 7 (Pd:Rh (wt%) = 2.5:0.1) exhibits superior catalytic activity compared to the reference catalyst, while bimetallic catalyst 8 (Pd:Rh (wt%) = 2.5:0.025) exhibits lower catalytic activity than the reference catalyst. Therefore, bimetallic catalysts exhibiting superior catalytic activity compared to the reference catalyst may be characterized by a Pd / Rh ratio (wt% / wt%) of 25 or less.

[0158] Figure 28 is similar to Figure 3, and shows NH to bimetallic catalysts 1, 5-9 and the reference catalyst. ３ This is a bar graph showing the effect of addition (changes in conversion rate and selectivity). Figure 29 is similar to Figure 4, and shows NH for bimetallic catalysts 1, 5-9 and the reference catalyst. ３ This bar graph shows the effect of the addition (change in yield).

[0159] As shown in Figure 28, in the bimetallic catalysts 1, 6, and 7, NH ３ The decrease in the selectivity of 4-ClAN due to the addition was suppressed compared to the case of the reference catalyst. In the case of bimetal catalyst 1, the yield of the product (see Figure 29) was NH ３ The level did not decrease even after the addition.

[0160] Next, we will explain the results of the characterization of the bimetallic catalyst 7, which showed superior catalytic activity compared to the reference catalyst.

[0161] Figure 30 is a graph showing the XPS spectra for the bimetallic catalyst 7, the Pd catalyst 10, and the Pd foil, similar to the case in Figure 8.

[0162] As shown in Figure 30, for Pd catalyst 10 (5%Pd / TiO2_R300), the chemical shift of the Pd 3d5 / 2 peak in the XPS spectrum is 0.6 eV higher in energy than the Pd 3d5 / 2 peak in the Pd foil spectrum. Similarly, for bimetal catalyst 7 (2.5%Pd-0.1%Rh / TiO2_R300), the chemical shift of the Pd 3d5 / 2 peak is 0.9 eV higher in energy than the Pd 3d5 / 2 peak in the Pd foil spectrum.

[0163] These results indicate that bimetallic catalysts exhibiting superior catalytic activity compared to the reference catalyst are characterized by a chemical shift of the Pd 3d5 / 2 peak in the XPS spectrum that is shifted to a higher energy side of 0.9 V or more relative to the Pd 3d5 / 2 peak in the Pd foil spectrum.

[0164] Figure 31 is a graph showing the XRD patterns for the bimetallic catalysts 7 and 9 and the Pd catalyst 10, similar to the case in Figure 9.

[0165] In the XRD pattern shown in Figure 31, it can be confirmed that, compared to the untreated bimetallic catalyst 9 (2.5%Pd-0.1%Rh / TiO2) bimetallic catalyst 7 (2.5%Pd-0.1%Rh_R300), the PdO peak disappears, and only the Pd peak remains. However, NH ３ Even for the Pd catalyst 10 (5%Pd / TiO2_R300), which does not have resistance to the Pd peak, it can be confirmed that only the Pd peak is present.

[0166] Similar to the case in Table 1 above, PdO / (Pd+PdO) was calculated based on the integrated intensity in the XRD pattern to determine the relative abundance of Pd and PdO for bimetallic catalysts 7 and 9 and Pd catalyst 10. Table 4 shows the values ​​of Pd, PdO, and PdO / (Pd+PdO) based on the integrated intensity in the XRD pattern. As shown in Table 4, bimetallic catalysts 7 and 9 are considered to be in a different chemical state from Pd catalyst 10, which contains only Pd, due to the presence of Rh.

[0167]

[0168] Figure 32 shows the NH31 of the bimetallic catalyst 1, 10-14, and the reference catalyst. ３ This is a scatter plot showing the effect of addition (rate of change in conversion rate and rate of change in selectivity). Bimetallic catalysts 1 and 10-14 have different supports (TiO ２ , CEO ２ pHS-Al ２ O ３ , ZrO ２ HBT, SiO ２ This is a catalyst that uses ).

[0169] Within the target region shown in Figure 32 (see the dotted line frame), points related to bimetallic catalysts 1 and 13-14 are located. Here, the CR of bimetallic catalyst 13 ＣＯＮＶ 0.00 and CR ＳＥＬ The value is 0.65. The CR of the bimetallic catalyst 14 ＣＯＮＶ is -2.07, CR ＳＥＬ It is 0.35.

[0170] As a result, the bimetallic catalyst 13-14 is NH３ In the presence of TiO, it was determined that the catalyst exhibited superior catalytic activity compared to the reference catalyst. On the other hand, the bimetallic catalyst 10-12 was determined not to exhibit superior catalytic activity compared to the reference catalyst because it was located outside the target region. In other words, in the case of the bimetallic catalyst, in order to obtain superior catalytic activity compared to the reference catalyst, TiO ２ Not limited to carriers, HBT carriers and SiO ２ A carrier can be used.

[0171] Figure 33 is a bar graph showing the effect of NH3 addition (changes in conversion rate and selectivity) on bimetallic catalysts 1, 10-14, and the reference catalyst. Figure 34 is a bar graph showing the effect of NH3 addition (changes in yield) on bimetallic catalysts 1, 10-14, and the reference catalyst.

[0172] As shown in Figure 33, in bimetallic catalysts 1 and 10-14, NH ３ The decrease in the selectivity of 4-ClAN due to the addition was suppressed compared to the case of the standard catalyst. In addition, in bimetallic catalysts 1, 10, and 13-14, NH ３ The decrease in the conversion rate of 4-ClNB due to the addition was also suppressed compared to the case of the standard catalyst. Furthermore, in the bimetal catalyst 14, the conversion rate of 4-ClNB was NH ３ The amount increased after addition, and the yield of the product (see Figure 34) also increased. From these results, it can be seen that with the bimetal catalyst 14, NH ３ It's possible that it's acting as a promoter rather than a toxic substance.

[0173] Table 5 summarizes the evaluation results for bimetallic catalysts 1, 7, and 9, and Pd catalysts 10 and 21. More specifically, Table 5 shows the conversion rate of 4-ClNB (NH₄) for bimetallic catalysts 1, 7, and 9, and Pd catalysts 10 and 21, respectively. ３ Before addition, selectivity of 4-ClAN (NH ３ Before addition, the conversion rate of 4-ClNB (NH ３ Selectivity of 4-ClAN (NH after addition) ３ After addition, the rate of change in conversion rate (CR) ＣＯＮＶ ), rate of change of selection rate (CR ＳＥＬThe Pd particle size, the PdO / (Pd+PdO) value based on the integrated intensity in the XRD pattern, and the chemical shift value of the Pd 3d5 / 2 peak relative to the Pd Foil in the XPS spectrum are shown. However, the Pd particle size of bimetallic catalysts 1, 7, and 9 was calculated from the XRD results using Scherrer's equation. In addition, the Pd particle size of Pd catalysts 10 and 21 was measured by the CO pulse method.

[0174]

[0175] Based on the above, bimetallic catalysts exhibiting superior catalytic activity compared to the reference catalyst are characterized by a chemical shift of the Pd 3d5 / 2 peak in the XPS spectrum that is shifted to a higher energy side of 0.9 V or more relative to the Pd 3d5 / 2 peak in the Pd Foil spectrum, by the fact that the Pd state is metallic Pd rather than PdO, and by the Pd particle size being less than 5.0 nm.

[0176] Next, an example of a deprotection reaction using a reduction catalyst according to this embodiment will be described.

[0177] For example, a reduction catalyst can be applied to the deprotection (reduction) reaction of benzylphenyl ether (BPE). As shown in equation (5) below, it was confirmed that toluene (PhMe) and phenol (PhOH) are produced as the deprotection reaction of benzylphenyl ether proceeds.

[0178]

[0179] Table 6 shows the results of the deprotection reaction of benzylphenyl ether (BPE) using Pd catalyst 1 (5% Pd / TiO2) (Entry 1) and Pd catalyst 16 (5% Pd / CB_R300, where CB is granular activated carbon A-BAC SP manufactured by Kureha Corporation) (Entry 2), respectively. The yields are based on detection results by GC-FID.

[0180]

[0181] In the deprotection reaction, benzylphenyl ether (BPE) was added at a concentration of 0.1 mol / L, methanol (MeOH) at a rate of 1 cc / min, and H₂２ A supply of 100 cc / min was provided. The volume of the reducing catalyst was 0.14 cc, and the contact time was 0.14 min. The pressure during the deprotection reaction was 0.2 MPaG, and the temperature was room temperature.

[0182] Although the present invention has been described above based on specific embodiments, these embodiments are merely illustrative, and the present invention is not limited to these embodiments. Not all of the components of the reduction catalyst shown in the above embodiments are necessarily essential, and at least those skilled in the art can appropriately select and omit them as long as they do not deviate from the scope of the present invention.

[0183] 1: Flow-type organic synthesis system 2: Flow-type fixed-bed reactor 3: Catalyst layer 4: Electric furnace 11: Liquid raw material tank 12: Pump for liquid raw materials 13: Preheater / precooler 21: Heat exchanger 25: Main drum 41: Product recovery drum

Claims

1. A reduction catalyst used in the reduction reaction of a compound, comprising: a carrier containing at least one of titania, alumina, silica, ceria, zirconia, magnesia, and activated carbon; and at least one metal supported on the carrier and selected from elements belonging to groups 8, 9, and 10 of the periodic table.

2. The reduction catalyst according to claim 1, wherein the reduction reaction is the reduction reaction of a compound having a nitro group or a nitrile group.

3. The reduction catalyst according to claim 2, wherein an amine compound is produced in the reduction reaction.

4. The reduction catalyst according to claim 1, wherein the reduction reaction is a deprotection reaction by reduction of a protecting group contained in the compound.

5. The reduction catalyst according to any one of claims 1 to 4, wherein the metal comprises at least one of palladium, rhodium, platinum, iridium, and ruthenium.

6. The reduction catalyst according to any one of claims 1 to 4, wherein the metal is palladium, the chemical shift of the Pd 3d5 / 2 peak in the spectrum measured by X-ray photoelectron spectroscopy is a shift of 2.3 eV or more to the higher energy side relative to the Pd 3d5 / 2 peak in the spectrum of palladium foil, the value of PdO / (Pd+PdO) in the integrated intensity of the X-ray diffraction pattern obtained by X-ray diffraction is 0, and the average particle size of the palladium measured by CO pulse method is 9.1 nm or more.

7. The reduction catalyst according to any one of claims 1 to 4, wherein the metal is rhodium, the chemical shift of the Rh 3d5 / 2 peak in the spectrum measured by X-ray photoelectron spectroscopy is a shift to a higher energy side of 1.3 eV or more relative to the Rh 3d5 / 2 peak in the spectrum of rhodium foil, and the average particle size of the rhodium measured by transmission electron microscopy is less than 5.0 nm.

8. The reduction catalyst according to any one of claims 1 to 4, wherein the metal is palladium and rhodium, or palladium and ruthenium.

9. The reduction catalyst according to any one of claims 1 to 4, wherein the metal is palladium and rhodium, the chemical shift of the Pd 3d5 / 2 peak in the spectrum measured by X-ray photoelectron spectroscopy is a shift to a higher energy side of 0.9 eV or more relative to the Pd 3d5 / 2 peak in the spectrum of palladium foil, the value of PdO / (Pd+PdO) in the integrated intensity of the X-ray diffraction pattern obtained by X-ray diffraction is 0, and the palladium particle size calculated from the Scherrer formula is less than 5.0 nm.

10. A reduction catalyst according to any one of claims 1 to 4, comprising the carrier and the metal supported thereon, obtained by reducing them at a predetermined temperature.

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