Hydrogenation reaction catalyst carrier

Abstract

To provide a hydrogenation reaction catalyst carrier having strong acid sites on the surface.SOLUTION: A hydrogenation reaction catalyst carrier of the present invention is a composite oxide containing La and Ce in a total of 50 mol% or more, wherein the particles of the composite oxide have an aspect ratio of 1.0 or more and 2.5 or less, and the composite oxide has a specific surface area of 55 m2 / g or more.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a hydrogenation reaction catalyst support.

Background Art

[0002] The Haber-Bosch process used to produce ammonia consumes a large amount of energy. In the Haber-Bosch process, about 60% of the consumed energy is recovered and secured as the enthalpy of ammonia. However, most of the remaining energy is lost during the production of hydrogen from natural gas, during the synthesis of ammonia, and during the separation of gases. Since ammonia synthesis by the Haber-Bosch process is carried out at very high temperatures (>450°C) and pressures (>20 MPa), there is a great demand to reduce the energy used. To suppress the global energy consumption, a catalyst that can synthesize ammonia under milder conditions (lower temperature and pressure) than the iron-based catalysts used in the Haber-Bosch process is needed.

[0003] In recent years, a method for producing ammonia under low-pressure conditions of about 1 MPa (10 atm) has been known. The Ru-based catalyst used for ammonia production is generally supported on a carrier.

[0004] According to Patent Document 1, it is said that ammonia can be synthesized at low temperature and low pressure by using a rare earth oxide as a carrier for supporting Ru.

[0005] Patent Document 2 discloses composite oxides and metal supports. For example, a ternary support containing three metal elements of Ba, La, and Ce is disclosed. Furthermore, an ammonia synthesis catalyst in which Ru is supported on this support is disclosed. According to Patent Document 2, since Ba is a strongly basic element with a higher value of the partial negative charge of oxygen compared to La and Ce, it is presumed that in a support in which Ba is unevenly exposed, the contact area between Ba and Ru increases, the number of active sites increases, and the ammonia synthesis activity increases.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 6-079177 [Patent Document 2] International Publication No. 2019 / 059190 [Summary of the Invention] [Problems to be Solved by the Invention]

[0007] Taking ammonia synthesis, which is a hydrogenation reaction, as an example, the rate-determining step of ammonia synthesis is the cleavage of the nitrogen bond. As shown in Patent Document 2 and the like, it is known that this process can be accelerated by electron donation to Ru. Therefore, as a catalyst, a catalyst in which an alkaline earth metal such as highly basic Ba is supported as a promoter on a hydrogenation reaction catalyst carrier (hereinafter, also simply referred to as "carrier"), and Ru is supported thereon is used, so that the electron-donating ability to Ru is improved, and the reaction efficiency of ammonia synthesis is improved. Thus, in hydrogenation reactions such as ammonia synthesis and methane synthesis, a catalyst in which a highly basic metal is supported on a carrier and a metal is supported thereon is considered to be effective.

[0008] However, according to the studies of the present inventors, it has been found that in a catalyst in which Ru is supported on Ba on the carrier used for ammonia synthesis, the expected catalytic activity may not be obtained. Explaining this cause with reference to FIG. 1, in a hydrogenation reaction catalyst, barium (Ba) 2 on the carrier (LaCeOx) 1 increases the catalytic activity by donating electrons to ruthenium (Ru) 3. However, since barium (Ba) 2 is too basic, barium (Ba) 2 reacts with carbon dioxide 4 in the air, and thus carbonation proceeds rapidly. And the carbonated Ba carbonate 5 is considered not to be able to give the electrons expected to ruthenium (Ru) 3.

[0009] The inventors considered that by imparting strong acid sites to the surface of the carrier, the basicity of alkaline earth metals and alkali metals is mitigated, resulting in a decrease in the reactivity between alkaline earth metals or alkali metals and carbon dioxide, and the stabilization of alkaline earth metals and alkali metals.

[0010] In view of the above circumstances, an object of the present invention is to provide a hydrogenation reaction catalyst carrier having strong acid sites on its surface.

Means for Solving the Problems

[0011] The inventors considered that if the basicity of Ba on the carrier could be mitigated, the reactivity with carbon dioxide in the air would decrease and Ba could be stabilized. Therefore, the inventors recalled that by imparting strong acid sites to the surface of the carrier, the basicity of Ba could be mitigated. Based on the above idea, the present invention was further studied and led to the invention of a hydrogenation reaction catalyst carrier, the gist of which is as follows.

[0012] (1) A composite oxide containing a total of 50 mol% or more of La and Ce, wherein the aspect ratio of the particles of the composite oxide is 1.0 or more and 2.5 or less, and the specific surface area of the composite oxide is 55 m 2 / g or more, characterized hydrogenation reaction catalyst carrier.

[0013] (2) The hydrogenation reaction catalyst carrier according to (1) above, characterized in that the full width at half maximum of the strongest X-ray diffraction peak is 1.2° or more.

[0014] (3) The hydrogenation reaction catalyst carrier according to (1) or (2) above, characterized in that the composite oxide contains 30 mol% or more of La and 25 mol% or more of Ce.

[0015] (4) The hydrogenation reaction catalyst carrier according to (1) or (2) above, characterized in that the composite oxide further contains one or more of Sm, Nd, Y, and Zr.

[0016] The hydrogenation reaction catalyst support according to (1) or (2) above, characterized in that the average secondary particle diameter is 0.08 to 12.00 μm.

Advantages of the Invention

[0017] According to the present invention, a hydrogenation reaction catalyst support having strong acid sites on the surface can be provided.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0019] The present invention is based on the idea that in a catalyst in which an alkaline earth metal such as Ba and an alkali metal such as Cs are supported on a support and Ru is supported thereon, if the basicity of the alkaline earth metal and alkali metal on the support can be relaxed, the reactivity with carbon dioxide in the air decreases, the formation of carbonates of the alkaline earth metal and alkali metal is suppressed, and as a result, the electron-donating ability to Ru increases and the ability as a catalyst is improved.

[0020] Specifically, the inventors conceived that by imparting strong acid sites to the surface of the carrier, the basicity of alkaline earth metals and alkali metals could be alleviated. If strong acid sites can be imparted to the surface of the carrier, it is considered that the basicity of alkaline earth metals and alkali metals is alleviated on the carrier, and as a result, the reactivity with carbon dioxide decreases and it becomes stabilized. Referring to FIG. 2 and explaining using a hydrogenation reaction catalyst having the same configuration as in FIG. 1, the points where barium (Ba) 2 and ruthenium (Ru) 3 are supported on the carrier (LaCeOx) 1 are the same, but strong acid sites 6 are imparted to the carrier (LaCeOx) 1. Thereby, since the basicity of barium (Ba) 2 is alleviated, it is considered that the reaction of barium (Ba) 2 with carbon dioxide 4 in the air is suppressed and the carbonation of barium (Ba) 2 is suppressed. As a result, it is considered that the electron-donating ability to ruthenium (Ru) 3 can be increased. Here, the acid site refers to a portion where the surface of the oxide is positively polarized, and for example, the surface metal ions and oxygen defect portions correspond to this.

[0021] The inventors further advanced the study and found that by controlling the particle shape of the hydrogenation reaction catalyst carrier, which is a composite oxide, a catalyst having strong acid sites on the surface of the carrier as described above can be produced. Hereinafter, the hydrogenation reaction catalyst carrier of the present invention will be described in detail.

[0022] <Hydrogenation reaction catalyst carrier> The hydrogenation reaction catalyst carrier of the present invention is a composite oxide containing 50 mol% or more of La and Ce in total, the aspect ratio of the particles of the composite oxide is 1.0 or more and 2.5 or less, and the specific surface area of the composite oxide is 55 m 2 / g or more.

[0023] As described above, examples of the acid site include an oxygen defect portion. When the carrier is composed of only La containing La 2 O 3 or only Ce containing CeO 2 , almost no oxygen defect portion is generated. Further, when the carrier is La 2 O 3 and rare earth oxides having a similar crystal structure (for example, Y 2 O3 ) Similarly, even in the case of a composite oxide composed of a solid solution, almost no oxygen defect portion is generated. In such a case, since the amount of acid sites is significantly reduced, the hydrogenation reaction catalyst support of the present invention is a composite oxide containing 50 mol% or more of La and Ce in total.

[0024] The content of La may be 1 mol% or more, 2 mol% or more, 5 mol% or more, 10 mol% or more, 15 mol% or more, 20 mol% or more, or 25 mol% or more. The content of Ce may be 1 mol% or more, 2 mol% or more, 5 mol% or more, 10 mol% or more, 15 mol% or more, or 20 mol% or more. From the viewpoint of increasing the amount of acid sites by generating an oxygen defect portion, it is more preferable to contain 30 mol% or more of La and 25% or more of Ce. The total content of La and Ce may be 60 mol% or more, 70 mol% or more, 80 mol% or more, 85 mol% or more, or 90 mol% or more.

[0025] (Aspect ratio of the particles of the composite oxide) The aspect ratio of the particles of the composite oxide of the present invention is 1.0 or more and 2.5 or less. The aspect ratio being 1.0 or more and 2.5 or less means that the shape of the particles is close to spherical. When the particles are spherical, the number of curved portions increases, so the ratio of steps and kinks on the particle surface increases. Steps and kinks become strong adsorption points. In the case of a composite oxide containing La and Ce, these become strong acid sites. When a support having many acid sites is used, the alkaline earth metal or alkali metal supported thereon is stabilized, so that high activity is exhibited when used as a catalyst. Also, when supporting a catalyst metal, the catalyst metal salt is adsorbed in molecular and ionic units, enabling fine dispersion and support. When the aspect ratio exceeds 2.5, the shape of the particles becomes needle-like. Since flat portions are formed on the needle-like particles, the number of steps and kinks decreases. The aspect ratio is preferably closer to 1.0, and may be 2.4 or less, 2.2 or less, 2.0 or less, or 1.8 or less.

[0026] The aspect ratio is determined as follows. A sample of the composite oxide is randomly scattered on an observation stage and observed with an electron microscope. Observation is carried out on a surface where 10 or more independent particles that do not contact or overlap with other particles are observed. For each individual independent particle, the lengths of the major axis (the longest line segment connecting two points on the outer periphery of the particle) and the minor axis (perpendicular to the major axis and the longest line segment connecting two points on the outer periphery of the particle) are determined, and the ratio of the two is taken as the aspect ratio of each particle. Five observed particles are used per field of view, and observation is carried out in four fields of view. The average value of the aspect ratios of the 20 observed particles is taken as the aspect ratio of the composite oxide.

[0027] (Specific surface area of the composite oxide) The composite oxide of the present invention has a specific surface area of 55 m 2 / g or more. When the specific surface area is small, for example, when used in a catalyst supporting Ru, Ru undergoes grain growth and the active sites decrease, resulting in a decrease in reaction activity. The upper limit of the specific surface area is not limited. However, it is not easy to produce a composite oxide with a specific surface area exceeding 200 m 2 / g, and the effect of improving the reaction activity also saturates. Therefore, the specific surface area may be 200 m 2 / g or less. The specific surface area may be 150 m 2 / g or less, 120 m 2 / g or less, 100 m 2 / g or less, 80 m 2 / g or less, or 70 m 2 / g or less.

[0028] The specific surface area is measured as follows. As a pretreatment, about 0.3 g of the sample is placed in a flask-type sample cell and degassed at 370 °C for 40 minutes under a nitrogen gas flow using a FloVac degassing device (manufactured by Anton Paar Japan). Then, using a surface area measuring device (manufactured by Anton Paar Japan, NOVAtouch NX-4LX-1), the specific surface area is measured by the BET method (one-point method) based on nitrogen gas adsorption.

[0029] (X-ray diffraction peak) The hydrogenation reaction catalyst support of the present invention preferably further has a full width at half maximum (FWHM) of the strongest X-ray diffraction peak of 1.2° or more. A large half width means low crystallinity. Low crystallinity is preferable because it results in more steps and kinks, and a larger amount of acid sites with specific strength.

[0030] The X-ray diffraction peak is determined by obtaining an X-ray diffraction spectrum with the horizontal axis being 2θ and the vertical axis being the diffraction intensity by performing powder X-ray diffraction measurement using a CuKα line as the radiation source with an X-ray diffractometer.

[0031] (Other elements) The composite oxide of the present invention may further contain one or more of Sm, Nd, Y, and Zr. By containing elements other than La and Ce as described above, oxygen defect portions are formed, so that the amount of acid sites can be increased.

[0032] (Average secondary particle diameter) The composite oxide of the present invention may be secondary particles having an average secondary particle diameter of 0.08 to 12.00 μm. Making the secondary particles have such a diameter is effective in preventing sedimentation of the slurry during washcoating. The secondary particle diameter is the median diameter measured using a particle size distribution measuring device. For example, using a laser diffraction / scattering particle size distribution measuring device (manufactured by Microtrac Bel Co., Ltd., MT3300-EX-II), the median diameter (D50) is calculated and used as the secondary particle diameter.

[0033] <Method for producing hydrogenation reaction catalyst support> The hydrogenation reaction catalyst support of the present invention can be produced by a method comprising the following steps.

[0034] (1) A neutralization step of dissolving raw materials of La and Ce in hydrochloric acid to obtain a LaCe aqueous solution, and flowing a NaOH solution into the LaCe aqueous solution at 25 to 90°C to form a coprecipitate. (2) An aging step of stirring the coprecipitate at 25 to 90°C for 0.5 to 3 hours. (3) After aging, the coprecipitate is put into diluted aqueous ammonia and stirred to form a slurry, and the first pulp washing step of performing a solid-liquid separation operation again is carried out. (4) After the first pulp washing, the coprecipitate is put into pure water and stirred to form a slurry, and the first pulp washing step of performing a solid-liquid separation operation again is carried out. (5) The coprecipitate after pulp washing is dried at 40 to 100 °C for 10 to 30 hours, crushed, and the coarse particles are removed by sieving in the drying and crushing step. (6) The calcination step of holding the coprecipitate after drying and crushing at 600 to 800 °C for 2 to 10 hours.

[0035] The hydrogenation reaction catalyst support of the present invention is a composite oxide containing La and Ce. However, the particles of the composite oxide containing La and Ce generally have a needle-like shape. The hydrogenation reaction catalyst support of the present invention has an aspect ratio of the particles of 1.0 or more and 2.5 or less by the above production method. However, the hydrogenation reaction catalyst support of the present invention is not limited to the above method, and other production methods may be used as long as a hydrogenation reaction catalyst support having the above-described characteristics can be obtained. Hereinafter, each step will be described.

[0036] (Neutralization step) First, a LaCe aqueous solution in which raw materials of La and Ce are dissolved in hydrochloric acid is prepared. As the raw materials of La and Ce, phosphates, carbonates, acetates, etc. of La and Ce can be used. Further, an NaOH aqueous solution is prepared as a neutralization precipitant. The prepared NaOH aqueous solution is poured into the prepared LaCe aqueous solution within 90 seconds, preferably within 60 seconds, more preferably within 20 seconds to generate a coprecipitate. Here, it is important to use hydrochloric acid as the acid for dissolving the raw materials and NaOH as the neutralization precipitant in order to make the aspect ratio and specific surface area of the composite oxide particles fall within an appropriate range. The reaction temperature is 25 to 90 °C. From the viewpoint of increasing the specific surface area of the produced composite oxide, the reaction temperature is preferably 40 °C or higher, more preferably 60 °C or higher, and still more preferably 80 °C or higher. By setting the reaction conditions in the neutralization step within the above range, the aspect ratio of the composite oxide can be adjusted to a desired range.

[0037] More specifically, in the growth of the composite oxide crystal particles, the crystal shape can be controlled by selecting the growing surface and the non-growing surface. As for the selection of the crystal growth surface, by adding an additive that adsorbs on a specific surface, the growth of the crystal surface on which the additive adsorbs can be suppressed. In the case of the composite oxide of La and Ce, namely LaCeO x crystal grows in the elongated direction, so by suppressing the crystal growth, the aspect ratio can be reduced. For such control of the crystal shape, it is effective to utilize a counter anion derived from an acid (chloride ion by adding hydrochloric acid) as an additive.

[0038] Regarding the neutralizing precipitant, sodium hydroxide has an ionization degree of 1 and a high reaction rate, so the particle growth of the composite oxide is suppressed and it is likely to be made into fine particles. As described above, in the case of the composite oxide of La and Ce, namely LaCeO x crystal grows in the elongated direction, so by suppressing the crystal growth, the aspect ratio can be reduced.

[0039] (Aging process) Next, the obtained coprecipitate is stirred for 0.5 to 3 hours and aged. The aging temperature is set to 25 to 90°C.

[0040] (Repulping washing process) Next, the aged coprecipitate is subjected to repulping washing twice. Here, repulping washing means that after solid-liquid separation, the coprecipitate is put into a predetermined solution, stirred to form a slurry, and then the solid-liquid separation operation is carried out again. For the first repulping washing, aqueous ammonia is used as the predetermined solution. The second repulping washing is carried out using pure water.

[0041] (Drying and crushing process) The coprecipitate after repulping washing is dried using a dryer. The drying temperature is 40 to 100°C and the drying time is 10 to 30 hours. After drying, it is crushed and coarse particles are removed by sieving.

[0042] (Firing process) Next, the coprecipitate after drying and crushing is calcined at 600 to 800°C for 2 to 10 hours. The heating rate to the calcination temperature is not limited, and for example, it may be 1 to 10°C / min. The cooling rate after calcination is also not limited, and for example, slow cooling may be used.

[0043] By setting the reaction temperature in the neutralization step, the aging temperature in the aging step, and the calcination temperature in the calcination step within the above ranges, the specific surface area of the composite oxide can be adjusted to a desired range.

[0044] Through the above steps, a hydrogenation reaction catalyst support, which is a composite oxide containing La and Ce, can be obtained.

[0045] The hydrogenation reaction catalyst support obtained as described above is an aggregate, and by pulverizing it using a jet mill or the like, secondary particles with an average particle diameter of 0.08 to 12.00 μm can be obtained.

Example

[0046] Hereinafter, the present invention will be specifically described using examples. The present invention is not limited to the specific examples shown below.

[0047] <Inventive Example 1> A hydrogenation reaction catalyst support was prepared by the production method described below.

[0048] 11 g of Ce carbonate and 8 g of lanthanum oxide were weighed as raw materials, and a LaCe hydrochloric acid solution in which the raw materials were dissolved using 30 g of hydrochloric acid (concentration 30%) as the raw material dissolution acid, and 250 ml of an NaOH aqueous solution (concentration 1.8 M) as the precipitant were prepared. The LaCe hydrochloric acid solution was poured into the NaOH aqueous solution in 60 seconds to form a coprecipitate containing La and Ce. The reaction temperature was 40°C.

[0049] The obtained coprecipitate was stirred for 1 hour and aged. The aging temperature was 40°C.

[0050] Next, the coprecipitate after aging was subjected to two lipulp washings. The first lipulp washing was performed using a solution obtained by diluting commercially available aqueous ammonia eight-fold. The second lipulp washing was performed using pure water.

[0051] Next, the coprecipitate after lipulp washing was dried at 80°C for 18 hours using a dryer, and then manually crushed for 30 minutes using an agate mortar and pestle. Next, the coprecipitate after manual crushing was crushed in an automatic mortar for 30 minutes, and then further wet-crushed with ethanol for 10 minutes using an agate mortar and pestle. Thereafter, coarse particles were removed by sieving.

[0052] Next, the dried and crushed coprecipitate was heated to 700°C at 2°C / min and calcined for 5 hours to obtain an aggregate of a hydrogenation reaction catalyst support which is a composite oxide containing La and Ce. The aggregate thus obtained is secondary particles of the composite oxide.

[0053] <Inventive Examples 2 to 20, Comparative Examples 21 to 30> The composition ratio of the hydrogenation reaction catalyst support was adjusted as shown in Table 2, and except that the raw material dissolution acid, precipitating agent, reaction temperature in the neutralization step, aging temperature in the aging step, crushing conditions in the drying and crushing step, and calcination temperature in the calcination step were those described in Table 1, a hydrogenation reaction catalyst support was obtained in the same manner as in Inventive Example 1. The crushing conditions described in Table 1 respectively indicate the following conditions.

[0054] A: Manual crushing (agate mortar, 30 minutes) B: A + Crushing in an automatic mortar for 30 minutes C: B + Wet crushing (ethanol) in an agate mortar for 10 minutes D: B + Crushing with a jet mill E: D + Crushing with a bead mill

[0055] The following evaluations were performed on the obtained hydrogenation reaction catalyst support.

[0056] (Aspect ratio) For each inventive example and comparative example, the aspect ratio was measured as follows. The sample was randomly scattered on the observation stage and observed with a scanning electron microscope (SEM). On the surface where 10 or more independent particles that were not in contact with or overlapping other particles were observed, for each individual independent particle, the length of the major axis (the longest line segment connecting two points on the outer periphery of the particle) and the minor axis (the longest line segment perpendicular to the major axis) were determined, and the ratio of the two was taken as the aspect ratio of each particle. Five observed particles were used per field of view, and observations were made in 4 fields of view. The average value of the aspect ratios of the 20 observed particles was taken as the aspect ratio of each example and comparative example.

[0057] (Specific surface area) For each inventive example and comparative example, the specific surface area was measured as follows. As a pretreatment, approximately 0.3 g of the sample was placed in a flask-type sample cell and degassed at 370 °C for 40 minutes under a nitrogen gas flow using a FloVac degassing device (manufactured by Anton Paar Japan). Then, using a surface area measuring device (manufactured by Anton Paar Japan, NOVAtouch NX-4LX-1), the specific surface area was measured by the BET method (one-point method) by nitrogen gas adsorption.

[0058] (Full width at half maximum of X-ray diffraction peak) For each inventive example and comparative example, the full width at half maximum of the X-ray diffraction peak was measured as follows. Using a powder sample, powder X-ray diffraction measurement was performed using an X-ray diffractometer with CuKα rays as the radiation source to obtain an X-ray diffraction spectrum with 2θ on the horizontal axis and diffraction intensity on the vertical axis. From the obtained X-ray diffraction spectrum, the full width at half maximum of the strongest diffraction peak was determined.

[0059] (Average secondary particle diameter) For each inventive example and comparative example, the average secondary particle diameter was calculated using a particle size distribution measuring device. Specifically, the median diameter (D50) calculated using MT3300-EX-II manufactured by MicrotracBEL was taken as the average secondary particle diameter.

[0060] (Evaluation of acid sites by temperature-programmed desorption method) For each inventive example and comparative example, the characteristics of the surface acid sites were evaluated by the temperature-programmed desorption method (TPD) in the following manner.

[0061] A sample of about 0.05 g was taken from the hydrogenation reaction catalyst support, and as a pretreatment, it was heated to 500 °C in 20% O 2 -He gas, held at 500 °C for 30 minutes, and then cooled to 100 °C. Next, at a sample temperature of 100 °C, ammonia gas diluted with helium gas (5% NH 3 -He) was added and held for 30 minutes to adsorb ammonia. Then, to remove the physically adsorbed ammonia, it was purged in helium gas for 30 minutes. Thereafter, the temperature was raised from 100 °C to 600 °C under the conditions of a helium gas flow rate of 30 mL / min and a heating rate of 20 °C / min, and the desorption amount was measured. A thermal conductivity detector (TCD) was used to detect the desorbed ammonia.

[0062] Referring to FIG. 3, the measurement results will be described. FIG. 3(a) shows the results of Invention Example 1. The horizontal axis represents temperature, and the vertical axis represents the intensity of the detected ammonia (unit: mmol / g·sec). According to TPD, ammonia adsorbed on weak acid sites desorbs at low temperatures (150 - 300 °C), and ammonia adsorbed on strong acid sites desorbs at high temperatures (400 - 550 °C). Therefore, if the amount of ammonia desorbing at 400 - 550 °C is large, it can be seen that there are many strong acid sites on the surface. In this example, the area in the range of 400 - 550 °C was calculated by integration and taken as the amount of high-intensity acid sites (the hatched part in FIG. 3(a)). FIG. 3(b) shows the results of Comparative Example 23 measured in the same manner. In this example, if the amount of high-intensity acid sites exceeds 0.140, it was determined that a hydrogenation reaction catalyst support having strong acid sites on the surface was produced and the problem was solved.

[0063] The above results are shown in Table 2.

[0064] [Table 1]

[0065] [Table 2]

[0066] In Invention Examples 1 to 21, a hydrogenation reaction catalyst carrier satisfying an aspect ratio of 1.0 or more and 2.5 or less and a specific surface area of 55 m 2 / g or more was obtained. As a result, the amount of high-intensity acid sites exceeded 0.140. Also, in each of the invention examples, secondary particles having a secondary particle diameter of 0.08 to 12 μm, which are preferable as the hydrogenation reaction catalyst carrier, could be obtained.

[0067] Comparative Example 22 is an example in which nitric acid was used as the raw material dissolution solution and aqueous ammonia was used as the precipitant. The suppression of crystal growth by the additive was not possible, and the reaction rate decreased due to the use of aqueous ammonia with a low ionization degree, resulting in no suppression of the particle growth of the composite oxide and no micronization. Therefore, the aspect ratio increased. As a result, the amount of high-intensity acid sites became 0.140 or less.

[0068] Comparative Example 23 is an example in which aqueous ammonia was used as the precipitant. The reaction rate decreased due to the use of aqueous ammonia with a low ionization degree, resulting in no suppression of the particle growth of the composite oxide and no micronization. Therefore, the aspect ratio increased. Also, the specific surface area decreased. As a result, the amount of high-intensity acid sites became 0.140 or less.

[0069] In Comparative Example 24, the reaction temperature in the neutralization step and the aging temperature in the aging step were low, resulting in a decrease in the specific surface area. As a result, the amount of high-intensity acid sites became 0.140 or less.

[0070] Comparative Example 25 is a comparative example that does not contain Ce. Comparative Example 25 contains Y in addition to La, but since La 2 O 3 and Y 2 O 3 have a similar crystal structure, it is considered that almost no oxygen defect part is generated and the amount of acid sites decreases. As a result, the amount of high-intensity acid sites became 0.140 or less.

[0071] Comparative Example 26 is a comparative example that does not contain Ce. Comparative Example 26 contains La 2 O 3Since it consists only of [the relevant substance], it is considered that almost no oxygen defect part is generated and the amount of acid sites is decreased. As a result, the amount of high-intensity acid sites became 0.140 or less.

[0072] Comparative Example 27 is a comparative example that does not contain La. Comparative Example 27 is CeO 2 Since it consists only of [the relevant substance], it is considered that almost no oxygen defect part is generated and the amount of acid sites is decreased. As a result, the amount of high-intensity acid sites became 0.140 or less.

[0073] In Comparative Example 28, the firing temperature in the firing process was high and the specific surface area became small. As a result, the amount of high-intensity acid sites became 0.140 or less.

[0074] In Comparative Example 29, the firing temperature in the firing process was high and the specific surface area became small. As a result, the amount of high-intensity acid sites became 0.140 or less.

Industrial Applicability

[0075] Since the hydrogen reaction catalyst carrier of the present invention has many strong acid sites on the surface, when an alkaline earth metal or an alkali metal is supported on the carrier, its basicity is alleviated, the reactivity with carbon dioxide in the air is decreased and stabilized, and in the catalyst in which a metal such as Ru is supported thereon, it is considered that the electron donating ability to Ru can be increased and the ability as a catalyst can be improved.

Explanation of Symbols

[0076] 1 Carrier (LaCeOx) 2 Barium (Ba) 3 Ruthenium (Ru) 4 Carbon dioxide 5 Ba carbonate 6 Strong acid site

Claims

1. A composite oxide containing La and Ce in a total amount of 50 mol% or more, wherein the aspect ratio of the particles of the composite oxide is 1.0 or more and 2.5 or less, The specific surface area of the composite oxide is 55 m ２ / g or more and which is a hydrogenation reaction catalyst support.

2. The hydrogenation reaction catalyst support according to Claim 1, wherein the full width at half maximum of the strongest X-ray diffraction peak is 1.2° or more.

3. The hydrogenation reaction catalyst support according to Claim 1 or 2, wherein the composite oxide contains 30 mol% or more of La and 25 mol% or more of Ce.

4. The hydrogenation reaction catalyst support according to Claim 1 or 2, wherein the composite oxide further contains one or more of Sm, Nd, Y, and Zr.

5. The hydrogenation reaction catalyst support according to Claim 1 or 2, wherein the average secondary particle diameter is 0.08 to 12.00 μm.

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