Method for producing nickel catalyst for hydrogenation reaction

Abstract

The method for preparing a nickel catalyst for hydrogenation according to the present invention is characterized by excellent safety and reaction activity of the nickel catalyst for hydrogenation of petroleum resins, as it involves a two-stage passivation process for the nickel catalyst after reduction.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0120131, filed on September 22, 2022, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a method for producing a nickel catalyst for hydrogenation reactions, and to a method for producing a nickel catalyst in which the safety and reaction activity of the catalyst are improved by a two-stage passivation process. [Background technology]

[0003] In general, the hydrogenation reaction of organic compounds is a reaction applied to reduce specific functional groups or convert unsaturated compounds into saturated compounds. It can be applied to a variety of compounds, such as reducing compounds with unsaturated functional groups such as ketones, aldehydes, and imines to alcohols and amines, or saturating the unsaturated bonds of olefin compounds, making it a commercially very important reaction.

[0004] Lower olefins (i.e., ethylene, propylene, butylene, and butadiene) and aromatic compounds (i.e., benzene, toluene, and xylene) are basic intermediates widely used in the petrochemical and chemical industries. Thermal cracking, or steam pyrolysis, is the primary process for forming these compounds, typically in the presence of steam and the absence of oxygen. Feedstocks can include petroleum gases and distillates such as naphtha, kerosene, and gas oil. Thermal cracking of naphtha and other crude oils can produce C4 oils containing ethylene, propylene, butane, and butadiene; C5 oils containing dicyclopentadiene (DCPD); cracked gasoline (containing benzene, toluene, and xylene); cracked kerosene (C9 and higher oils); cracked heavy oils (ethylene residue, bottom oil); and hydrogen gas, which can then be polymerized to produce petroleum resins.

[0005] However, polymerized petroleum resins contain double bonds of aromatic moieties (hereinafter referred to as "aromatic double bonds") and double bonds of aliphatic moieties (hereinafter referred to as "olefinic double bonds"), and if the content of olefinic double bonds is high, the quality of the petroleum resin may deteriorate. In this case, a hydrogenation process in which hydrogen is added to the olefinic double bonds saturates the unsaturated double bonds, brightening the color and reducing the characteristic odor of petroleum resins, thereby improving the quality.

[0006] In order to control the content of aromatic double bonds during the hydrogenation of petroleum resins, it is necessary to selectively hydrogenate the olefinic bonds of the polymer resin. Selective hydrogenation of olefinic double bonds is typically achieved by contacting hydrogen and the reactants undergoing the hydrogenation reaction with a noble metal catalyst such as palladium (Pd) or platinum (Pt). However, these noble metal catalysts are very expensive, which is a major cause of increased costs. Therefore, commercially, petroleum resins are hydrogenated using nickel (Ni)-based catalysts.

[0007] Due to its self-heating nature, nickel powder catalysts for petroleum resin hydrogenation reactions require safe methods for their transportation, storage, and use. To achieve this, a process is applied to ensure the safety of nickel catalysts. In the case of nickel catalysts, a passivation process is generally carried out using a nitrogen mixed gas that contains some air after the reduction process. During the passivation process, the highly reactive nickel component reacts with air and is converted into less reactive nickel oxide (NiO), ensuring the safety of the nickel catalyst.

[0008] However, some of the formed nickel oxide is not regenerated into nickel during the hydrogenation reaction, resulting in reduced reaction activity and a higher catalyst consumption compared to other catalysts. While reducing the ratio of nickel converted to nickel oxide in a nickel catalyst can increase hydrogenation reaction performance and reduce catalyst consumption, it also increases the risk of sudden heat generation during catalyst transportation, storage, and use, raising environmental safety concerns. Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention provides a method for producing a nickel catalyst for hydrogenation reaction that has excellent reaction activity in hydrogenation reaction while improving the safety of the nickel catalyst. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention provides a method for producing a nickel catalyst, including the steps of: preparing a catalyst precursor mixture containing a nickel precursor (Step 1); precipitating the catalyst precursor mixture to obtain a catalyst precursor (Step 2); drying, calcining, and reducing the catalyst precursor to prepare a catalyst (Step 3); a first passivation step of passivating the catalyst using a mixed gas containing air and nitrogen (Step 4); and a second passivation step of passivating the catalyst using a mixed gas containing air and nitrogen at a temperature different from that of the first passivation step (Step 5) after the first passivation step.

[0011] The present invention also provides a nickel catalyst comprising nickel on a solid support, which has an H2-TPR peak maximum at 120 to 200°C, a half-width of the H2-TPR peak of 90 or less, and a stability of 55 to 70% calculated by the following formula 1: [Formula 1] Degree of stabilization (%) = ((area of ​​the base of the TPR graph of the catalyst ÷ weight of the sample) / (area of ​​the base of the TPR graph of the oxidized catalyst ÷ weight of the sample)) × 100 In the present invention, terms such as first and second are used to describe various components, and the terms are used only to distinguish one component from another.

[0012] Furthermore, the terms used in this specification are merely used to describe exemplary embodiments and are not intended to limit the present invention.

[0013] The singular expression includes the plural expression unless the context clearly indicates otherwise.

[0014] In this specification, the terms "comprises," "comprises," or "having" are intended to describe embodied features, numbers, steps, components, or combinations thereof, and do not exclude the possibility of one or more other features, numbers, steps, components, combinations, or additions thereof.

[0015] Furthermore, in this specification, when a layer or element is referred to as being formed "on" another layer or element, it means that the layer or element is formed directly on the other layer or element, or that other layers or elements can be additionally formed between the layers, on the object, or on the substrate.

[0016] Although the present invention can be embodied in various forms through various modifications, specific embodiments are described in detail below by way of example, but it should be understood that this is not intended to limit the invention to the specific disclosed embodiments, and that the invention encompasses all modifications, equivalents, and alternatives falling within the spirit and technical scope of the invention.

[0017] The term "nickel catalyst" as used in the present invention means a structure in which metallic nickel particles and a support are physically and chemically bonded, and the "nickel" in the "nickel catalyst" includes both nickel metal and nickel oxide.

[0018] The present invention will be described in detail below.

[0019] The present invention relates to a method for producing a nickel catalyst, which relates to a step of passivating the catalyst after reduction, and which involves carrying out the passivation step in two stages at different temperatures.

[0020] Nickel catalysts typically undergo a passivation process to ensure safety, but the degree of passivation can affect the catalyst's safety or reaction activity when used in subsequent reactions. Therefore, the present invention is characterized by the excellent catalytic safety and reaction activity achieved by preparing a nickel catalyst through a two-step passivation process.

[0021] The present invention will be described in detail below for each step.

[0022] (Stage 1) Step 1 of the present invention is to prepare a catalyst precursor mixture that includes a nickel precursor.

[0023] The nickel catalyst used in the present invention can be prepared using various nickel precursors, such as nickel, nickel nitrate, acetate, sulfate, and chloride, and preferably, nickel sulfate, including sulfate, but not limited to, nickel sulfate.

[0024] According to one embodiment of the present invention, the catalyst precursor mixture of Step 1 may further include one or more of a support and a promoter precursor. The type of the support is not particularly limited, and may be, for example, one or more selected from the group consisting of SiO2, Al2O3, MgO, MgCl2, CaCl2, ZrO2, TiO2, BO3, CaO, ZnO, BaO, ThO2, SiO2-Al2O3, SiO2-MgO, SiO2-TiO2, SiO2-VO5, SiO2-CrO2O3, SiO2-TiO2-MgO, and zeolite. Among them, a silica (SiO2)-containing support is typically used.

[0025] The type of the accelerator precursor is not particularly limited, and may be, for example, an oxide, nitrate, acetate, sulfate, chloride, or combination thereof containing copper, potassium, sulfur, or the like. Preferably, copper sulfate can be used, but is not limited thereto.

[0026] The catalyst precursor mixture can be prepared by mixing the components in a solvent. The type of solvent is not particularly limited, but water, methanol, ethanol, or the like can be used, and water is preferably used. The method for mixing the catalyst precursor mixture is also not particularly limited. For example, the catalyst precursor mixture can be prepared by dissolving nickel and a promoter precursor in a solvent and then adding a support. Alternatively, the support can be added to a solvent to prepare a suspension, and then nickel and a promoter precursor can be added.

[0027] (Stage 2) Step 2 of the present invention is to prepare a catalyst precursor from the catalyst precursor mixture prepared in step 1 using a precipitating agent.

[0028] In step 2, the method for preparing the catalyst precursor mixture into the catalyst precursor is not particularly limited, and the catalyst precursor may be prepared by a precipitation method, specifically, a co-precipitation method, an impregnation method, an immersion precipitation method, or the like.

[0029] For example, in step 1, a catalyst precursor is prepared by adding a nickel precursor, a promoter precursor, and a support to a solvent, and then a precipitant is added to the catalyst precursor mixture, and the precipitant is immersed in the solid support in which the nickel and promoter components are suspended in the solvent.

[0030] The precipitant can be selected in consideration of the amount of nickel supported in the catalyst, the size of nickel crystals, the dispersibility of nickel, etc. Preferably, the precipitant in step 2 can be one or more of sodium carbonate and sodium bicarbonate.

[0031] (Stage 3) Step 3 of the present invention is to dry, calcinate, and reduce the catalyst precursor prepared in step 2 to prepare a catalyst.

[0032] First, drying is a step of drying the solvent from the catalyst precursor to produce a dried product. The drying temperature and time can be selected as long as they are sufficient to remove the solvent, and are not particularly limited, but can be performed at a temperature of 80 to 200°C for 5 to 30 hours. Furthermore, prior to drying, the method can optionally further include a step of washing and filtering the catalyst precursor produced in step 2.

[0033] After preparing the dried product, the catalyst precursor is calcined. Calcination can be carried out in an air atmosphere at 180 to 500°C, 200 to 450°C, or 250 to 400°C. If the calcination temperature is below this range, the dispersion of the active species, nickel, decreases, while if it exceeds this range, nickel sintering may occur, resulting in a decrease in reactivity.

[0034] Since the calcination is generally carried out in air, the nickel contained in the catalyst precursor is mostly present in the form of nickel oxide, which generally has lower hydrogenation activity than nickel and is therefore generally reduced before use. Therefore, after calcination, the catalyst precursor is reduced before use as a catalyst.

[0035] The reduction in step 3 can be carried out in a hydrogen atmosphere at a temperature of 300 to 600°C. If the reduction temperature is below this range, the catalyst may not be properly reduced, and if the reduction temperature is above this range, sintering of the active metal may occur. More preferably, the reduction can be carried out at a temperature of 350 to 550°C or 400 to 500°C.

[0036] (Stage 4) The nickel catalyst produced by reduction of the catalyst precursor undergoes a passivation step, as described above, to make it safe for transportation, storage, and use. Step 4 of the present invention corresponds to the first passivation step of the two-step passivation step of the present invention.

[0037] Previous passivation steps have been performed by converting part of the nickel in the catalyst to nickel oxide in an air atmosphere or by immersing the catalyst in an organic solvent that blocks air. However, these methods have struggled to satisfy both the safety and reaction activity of the catalyst. Through continued experiments, the present researchers have confirmed that by performing a two-stage passivation process at different temperatures, it is possible to produce a catalyst with excellent reaction activity while ensuring safety in transportation, storage, and use.

[0038] The first passivation step involves passivating the catalyst using a mixed gas containing air and nitrogen. The air may contain nitrogen, oxygen, carbon dioxide, carbon monoxide, argon, etc. More specifically, the air may contain about 78 vol% nitrogen, about 21 vol% oxygen, and about 0.93 vol% argon, and may further contain carbon dioxide, carbon monoxide, and water vapor.

[0039] Preferably, the air content of the air and nitrogen mixed gas in step 4 is 0.1 to 2 vol% relative to the total volume. If the air content in the mixed gas is less than this range, the conversion of nickel to nickel oxide may not be adequate, while if it exceeds this range, the catalytic activity may decrease. More preferably, the air content of the mixed gas is 0.15 vol% or more, 0.2 vol% or more, or 0.3 vol% or more, and 1.7 vol% or less, 1.5 vol% or less, or 1.2 vol% or less relative to the total volume of the mixed gas.

[0040] Preferably, the first passivation step of Step 4 can be carried out at a temperature of 15 to 50°C. The temperature of the first passivation step of the present invention is preferably lower than that of the second passivation step. In the first passivation step, passivation proceeds relatively gradually under mild conditions through contact with air, allowing for stable passivation of the catalyst. More preferably, the first passivation step can be carried out at a temperature of 17°C or higher, 20°C or higher, or 22°C or higher, and 45°C or lower, 40°C or lower, 35°C or lower, or 30°C or lower.

[0041] Preferably, the first passivation step of step 4 can be carried out for 5 to 24 hours. The duration of the first passivation step can affect the stability of the passivated catalyst, and if the duration of the first passivation step is less than 5 hours or more than 24 hours, the stability and reaction activity of the catalyst may be reduced.

[0042] (Stage 5) Step 5 of the present invention is to carry out a second passivation step after the first passivation step of the catalyst using a gas mixture containing air and nitrogen.

[0043] Meanwhile, the mixed gas used in this step is a mixed gas containing air and nitrogen, and has the same composition as the mixed gas used in the first passivation step in Step 4. For the composition of the air and the volume of air in the mixed gas, see the description of Step 4.

[0044] Preferably, the second passivation step in step 5 can be performed at a higher temperature than the first passivation step. As described above, after the first passivation step is performed under mild conditions, the second passivation step can be performed again to further passivate the surface of unpassivated nickel or passivated nickel oxide. When the nickel catalyst is passivated in two steps, the catalyst is made safe enough for commercial use and exhibits excellent activity in hydrogenation reactions. More specifically, the second passivation step in step 5 can be performed at a temperature of 50°C or higher, 55°C or higher, or 60°C or higher, and 150°C or lower, 140°C or lower, 130°C or lower, or 120°C or lower.

[0045] The present invention also provides a nickel catalyst comprising nickel on a solid support, which has an H2-TPR peak maximum at 120 to 200°C, a half-width of the H2-TPR peak of 90 or less, and a stability of 55 to 70% calculated by the following formula 1: [Formula 1] Degree of stabilization (%) = ((area of ​​the base of the TPR graph of the catalyst ÷ weight of the sample) / (area of ​​the base of the TPR graph of the oxidized catalyst ÷ weight of the sample)) × 100 The nickel contained in the nickel catalyst and the carrier are described above.

[0046] The H2-TPR (Temperature Programmed Reduction) is a measurement method for evaluating the reduction ability of a catalyst using hydrogen gas. TPR evaluates the degree of reduction of a catalyst by heating a catalyst sample to a target temperature at a set heating rate while flowing hydrogen gas through the catalyst sample. A peak appears when the catalyst sample is reduced by the reducing gas, and the maximum value of the peak indicates the point at which the amount of hydrogen consumed is highest at a specific temperature. Furthermore, a smaller half-width of the peak indicates higher uniformity of the active component of the prepared nickel catalyst. Preferably, the nickel catalyst of the present invention has an H2-TPR peak maximum at 120-200°C, 125-195°C, 130-190°C, or 135-185°C. If the H2-TPR peak value is less than 120°C, the catalyst's safety in use is significantly reduced, it is prone to heat generation in air, and the risk of an accident increases. If the H2-TPR peak value exceeds 200°C, the activity decreases during the reaction, resulting in increased catalyst consumption.

[0047] The half-width of the H2-TPR peak is 90 or less. If the half-width of the H2-TPR peak is broad, the uniformity of the catalyst performance decreases; a smaller half-width is advantageous in ensuring uniformity of the catalytic activity and life performance and enabling safe control of the reaction process; a lower half-width is advantageous in providing superior catalyst performance; there is no lower limit, but it may be, for example, 85 or less, 80 or less, or 75 or less, or 30 or more, 35 or more, or 40 or more.

[0048] In addition, the nickel catalyst according to the present invention has a stability of 55% to 70% as calculated by the following equation 1. The bottom area of ​​the H2-TPR graph represents the amount of hydrogen consumed during the catalyst reduction process. Meanwhile, in the following equation 1, the "TPR graph of the catalyst" refers to a TPR graph measured without pretreatment, and the "TPR graph of the oxidized catalyst" refers to a TPR graph of a catalyst that was separately subjected to oxidation pretreatment before TPR measurement.

[0049] [Formula 1] Degree of stabilization (%) = ((area of ​​the base of the TPR graph of the catalyst ÷ weight of the sample) / (area of ​​the base of the TPR graph of the oxidized catalyst ÷ weight of the sample)) × 100 The stability index is calculated by analyzing each TPR graph and indicates the change in hydrogen consumption rate with increasing temperature, i.e., the degree of change in the reducing power of the catalyst. A high calculated stability index has the advantage of increasing the safety of use of the catalyst, but the disadvantage of accompanying a decrease in catalyst activity and lifespan. A low stability index has the disadvantage of increasing the risk of self-heating when the catalyst is exposed to air, but has the effect of increasing catalyst activity and lifespan. Therefore, it is preferable that the stability index be within a specific range that simultaneously satisfies the safety of use, activity, and lifespan of the catalyst. The sample pretreatment method, TPR measurement conditions, and method for calculating the base area of ​​the graph for measuring the H2-TPR graph are described in detail in the Examples below. [Effects of the Invention]

[0050] As described above, the method for producing a nickel catalyst for hydrogenation reaction according to the present invention includes a two-stage passivation process, thereby providing excellent catalyst safety and reaction activity. [Brief explanation of the drawings]

[0051] [Figure 1] 1 is an image of the H2-TPR graph of the nickel catalyst prepared in Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0052] Preferred examples are presented below to aid in understanding the invention, but the following examples are merely for illustrative purposes and are not intended to limit the scope of the invention. [Example]

[0053] Example 1 1.5 kg of amorphous silica powder, 20 kg of nickel sulfate, 222 g of copper sulfate, and 60 L of distilled water were placed in a precipitation vessel and stirred, then heated to 75°C. 75 L of precipitant solution containing 12.5 kg of sodium carbonate was pumped into the raw solution reactor over one hour using a diaphragm pump. After precipitation was complete, the mixture was filtered using a filter press and washed with 600 L of distilled water. After washing, the mixture was dried in a drying oven at 120°C for 24 hours. After dividing the mixture into small portions, it was calcined in an air atmosphere at 300°C. After dividing the mixture again, it was reduced in a hydrogen atmosphere at 400°C.

[0054] After reduction, the catalyst was treated with a nitrogen mixed gas containing 1 vol% air at 25°C for 12 hours, and then the temperature was increased to 60°C and heat-treated for an additional hour. After gradually increasing the air concentration, the catalyst was safely recovered.

[0055] The recovered catalyst contained 78.2 parts by weight of NiO and 0.8 parts by weight of CuO based on the weight of the catalyst. The average size of the nickel crystallites was measured to be 4.1 nm. The BET specific surface area was 245 m 2 / g, total pore volume 0.33m 3 / g and has an average pore size of 5.5 nm.

[0056] Example 2 After the reduction, the catalyst was prepared in the same manner as in Example 1, except that it was treated with a nitrogen mixed gas containing 1 vol% air at 25°C for 12 hours, and then the temperature was increased to 80°C and further heat-treated for 1 hour.

[0057] Example 3 After the reduction, the catalyst was treated with a nitrogen mixed gas containing 1 vol% air at 25°C for 12 hours, and then the temperature was increased to 100°C and the catalyst was further heat-treated for 1 hour. The catalyst was prepared in the same manner as in Example 1.

[0058] Example 4 After the reduction, the catalyst was treated with a nitrogen mixed gas containing 1 vol% air at 25°C for 12 hours, and then the temperature was increased to 120°C and the catalyst was further heat-treated for 1 hour. The catalyst was prepared in the same manner as in Example 1.

[0059] Comparative Example 1 The catalyst was prepared as in Example 1, and after reduction, the powder was heat-treated at 25°C for 12 hours using a nitrogen mixed gas containing 1 vol% air, and the air concentration was gradually increased to safely recover the catalyst.

[0060] Comparative Example 2 A catalyst was prepared in the same manner as in Comparative Example 1, except that after reduction, the catalyst was treated with a nitrogen mixed gas containing 1 vol % air at 60° C. for 12 hours.

[0061] Comparative Example 3 A catalyst was prepared in the same manner as in Comparative Example 1, except that after reduction, the catalyst was treated with a nitrogen mixed gas containing 1 vol % air at 80° C. for 12 hours.

[0062] Comparative Example 4 A catalyst was prepared in the same manner as in Comparative Example 1, except that after reduction, the catalyst was treated with a nitrogen mixed gas containing 1 vol % air at 100° C. for 12 hours.

[0063] Comparative Example 5 A catalyst was prepared in the same manner as in Comparative Example 1, except that after reduction, the catalyst was treated with a nitrogen mixed gas containing 1 vol % of air at 120° C. for 12 hours.

[0064] <Experimental Example> The catalyst prepared above was characterized and analyzed and its reaction activity was measured by the following methods.

[0065] (1)H2-TPR analysis The catalytic properties were analyzed using a MicrotracBEL Belcat II device. The H2-TPR graph of the catalyst prepared in Example 1 is shown in Figure 1. The reduction of the oxidized catalyst and the amount of hydrogen consumed during the catalyst reduction process were measured, and the catalyst stability was calculated based on the ratio using the following equation 1.

[0066] The sample weight was 50 mg, the analytical conditions for the oxidized catalyst were as shown in Table 1 below, and the analytical conditions for the catalyst were as shown in Table 2 below. The TPR graph was analyzed using the Nonlinear Curve Fit (Gauss) method in the Origin 9.1 program, and the results are shown in Table 3 below.

[0067] [Formula 1] Degree of stabilization (%) = ((area of ​​the base of the TPR graph of the catalyst ÷ weight of the sample) / (area of ​​the base of the TPR graph of the oxidized catalyst ÷ weight of the sample)) × 100

[0068] [Table 1]

[0069] [Table 2]

[0070] (2) Catalytic activity evaluation A 300 mL autoclave equipped with a hollow shaft stirrer and a stirring speed of 1,600 rpm was used. Non-hydrogenated petroleum resin (Hanwha Solutions DCPD polymer resin: 20 wt% styrene monomer and 80 wt% DCPD) was dissolved in cyclohexane at 30 wt% to produce 75 g of a mixed solution. Hydrogenation was then carried out at 200°C and 50 bar using 2% of the catalyst (based on the mass of the petroleum resin). One hour after the start of the reaction, the petroleum resin was analyzed by NMR, and the hydrogenation ratio relative to the non-hydrogenated petroleum resin was calculated and shown in Table 3.

[0071] [Table 3]

[0072] As can be seen from Table 3, the nickel catalysts prepared by the methods of the present invention were found to have excellent catalytic stability and reaction activity. In contrast, the catalysts of Comparative Examples 1 to 4 were less stable than the catalysts of the Examples, and when exposed to air during the experiment, they rapidly self-heated, making it impossible to conduct activity reaction tests. The catalysts of Comparative Examples 4 and 5 were found to have improved stability compared to the Examples, but their activity was significantly reduced. The catalysts of the present invention achieved catalytic stability and excellent reaction activity through a two-stage passivation process.

Claims

1. preparing a catalyst precursor mixture comprising a nickel precursor (Step 1); Step 2: Precipitating the catalyst precursor mixture to obtain a catalyst precursor; Step 3: drying, calcining, and reducing the catalyst precursor to prepare a catalyst; a first passivation step (step 4) in which the catalyst is passivated using a gas mixture containing air and nitrogen; After the first passivation step, a second passivation step (step 5) is performed using a mixed gas containing air and nitrogen at a temperature different from that of the first passivation step. A method for producing a nickel catalyst.

2. The catalyst precursor mixture of step 1 further comprises one or more of a support and a promoter precursor; The method for producing the nickel catalyst according to claim 1 .

3. The precipitating agent in step 2 is one or more of sodium carbonate and sodium bicarbonate. The method for producing the nickel catalyst according to claim 1 .

4. The drying in step 3 is carried out at a temperature of 80 to 200°C. The method for producing the nickel catalyst according to claim 1 .

5. The firing in step 3 is carried out in an air atmosphere at a temperature of 180 to 500°C. The method for producing the nickel catalyst according to claim 1 .

6. The reduction in step 3 is carried out in a hydrogen atmosphere at a temperature of 300 to 600°C. The method for producing the nickel catalyst according to claim 1 .

7. The air is contained in an amount of 0.1 to 2 vol% based on the total volume of the air and nitrogen mixed gas of step 4. The method for producing the nickel catalyst according to claim 1 .

8. The first passivation step of step 4 is carried out at a temperature of 15 to 50°C. The method for producing the nickel catalyst according to claim 1 .

9. The first passivation step of step 4 is carried out for 5 to 24 hours. The method for producing the nickel catalyst according to claim 1 .

10. The second passivation step of step 5 is carried out at a higher temperature than the first passivation step. The method for producing the nickel catalyst according to claim 1 .

11. The second passivation step of step 5 is carried out at a temperature of 50 to 150°C. The method for producing the nickel catalyst according to claim 1 .

12. comprising nickel on a solid support; H at 120-200°C ２ - has a maximum value of the TPR peak, The H ２ - The half-width of the TPR peak is 90 or less, The stability calculated by the following formula 1 is 55 to 70%. Nickel catalyst. [Formula 1] Stability (%) = ((area of ​​the base of the TPR graph of the catalyst ÷ weight of the sample) / (area of ​​the base of the TPR graph of the oxidized catalyst ÷ weight of the sample)) × 100

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