Inorganic compound and method for producing same

Abstract

The present invention addresses the problem of providing pseudo-boehmite that is unlikely to undergo a decrease in pore volume even in the presence of an acid. The problem can be solved by an inorganic compound in which the Al content (bulk) falls within the range 30 mass% to 80 mass% in terms of Al2O3, the Si content (bulk) falls within the range 20 mass% to 70 mass% in terms of SiO2, the total pore volume falls within the range 1.3 mL / g to 2.3 mL / g, and the ratio of the Si content (in the vicinity of the surface), as measured by X-ray photoelectron spectroscopy, is 60% or more relative to the Si content (bulk).

Description

Inorganic compounds and methods for producing the same

[0001] This invention relates to an inorganic compound with high acid resistance and a method for producing the same.

[0002] Inorganic compounds containing aluminum, an amphoteric element, readily form so-called amphoteric compounds, which act as bases in the presence of acids and acids in the presence of bases. Such compounds present the challenge of being easily altered in the presence of acids or bases. For example, aluminum hydroxides such as boehmite are known as amphoteric hydroxides and are prone to alteration under acidic conditions.

[0003] Aluminum compounds such as aluminum hydroxide are widely used as raw materials or products for catalyst supports. Generally, γ-alumina, which has excellent thermal stability and mechanical strength, is often used as a catalyst support, and this is generally produced by calcining boehmite gel (pseudoboehmite). Neutralization of acidic or basic aluminum salt solutions or hydrolysis of aluminum alkoxides are commonly used to prepare this pseudoboehmite powder.

[0004] Patent Document 1 describes a process in which pseudo-boehmite powder is mixed with a decoagulant such as nitric acid or acetic acid, kneaded, and then subjected to extrusion molding, drying, and calcination to produce an alumina support. Generally, catalyst supports require properties such as a large specific surface area, appropriate pore size and pore distribution, large pore volume, and high mechanical strength. These properties are greatly influenced by conditions such as kneading and extrusion molding. Furthermore, when pseudo-boehmite powder is mixed with a decoagulant such as nitric acid or acetic acid, alteration occurs, making it difficult to prepare a support while maintaining the pore volume and pore size of the pseudo-boehmite.

[0005] Japanese Patent Publication No. Hei 8-268716, Japanese Patent Publication No. 2021-151942, Japanese Patent Publication No. 2023-137463

[0006] Given these circumstances, the present invention aims to provide a pseudo-boehmite that is less susceptible to deterioration in the presence of acid. The inventors first focused on protecting the pseudo-boehmite with an inorganic compound that is less susceptible to deterioration in the presence of acid, and selected silica as an inorganic compound containing Si, which is an element close to Al but not an amphoteric element. However, in conventional manufacturing methods (for example, Japanese Patent Application Publication No. 2023-137463), it was not possible to coat the surface of the pseudo-boehmite with a sufficient amount of silica (on the contrary, the surface area of ​​the pseudo-boehmite increased), resulting in a significant decrease in pore volume in the presence of acid. Furthermore, although this can be improved to some extent by increasing the silica content, another problem arises: the pseudo-boehmite content decreases, resulting in a smaller pore volume. In other words, providing a pseudo-boehmite that is less susceptible to a decrease in pore volume even in the presence of acid is a new problem that has not been solved in the prior art.

[0007] The inventors conducted further studies and discovered a method of obtaining a slurry by dispersing a pseudo-boehmite with a large specific surface area and pore volume with silica in water, and then aging the slurry so that its isoelectric point falls within the range of 2.5 to 4.5. Using this method, the surface of the pseudo-boehmite can be coated with a sufficient amount of silica. In this method, by using the isoelectric point of the slurry as an indicator, it became possible to easily coat the surface of the pseudo-boehmite with a sufficient amount of silica without having to finely adjust operating factors such as temperature, time, and pH during aging. As a result, it became possible to provide a pseudo-boehmite that does not easily decrease in pore volume even in the presence of acid, that is, a pseudo-boehmite that does not easily deteriorate in the presence of acid.

[0008] According to one aspect of the present invention, a pseudo-boehmite is provided that does not easily reduce pore volume even in the presence of acid.

[0009] This is the FT-IR spectrum of the inorganic compound of Example 1. This is the difference spectrum of the inorganic compound of Example 1.

[0010] The inorganic compounds according to the embodiments of the present invention (hereinafter also referred to as "inorganic compounds according to this embodiment") and the methods for producing inorganic compounds according to the embodiments of the present invention (hereinafter also referred to as "production methods according to this embodiment") will be described in detail below. In this specification and the accompanying documents, when a numerical range is indicated by "~", that numerical range includes both an upper and lower limit. For example, when it is written as "1 to 2", it means "1 or more and 2 or less".

[0011] [Inorganic compound according to this embodiment] The inorganic compound according to this embodiment has an Al content (bulk) of Al ２ O ３ The Si content (bulk) is in the range of 30% to 80% by mass, and is SiO ２ The Si content is in the range of 20% to 70% by mass, the total pore volume is in the range of 1.3 mL / g to 2.3 mL / g, and the Si content (near the surface) measured by X-ray photoelectron spectroscopy is 60% or more of the Si content (bulk).

[0012] The inorganic compound according to this embodiment contains an inorganic compound containing Al, that is, the Al content (bulk) is Al ２ O ３ The amount must be in the range of 30% to 80% by mass. One embodiment of this product is described below assuming the inclusion of pseudoboehmite, however, this embodiment does not require the inclusion of pseudoboehmite. Pseudoboehmite is a type of inorganic compound containing Al, and is also an amphoteric compound, sharing the common problem of readily reacting with acids; therefore, the scope of this technical concept can be extended to inorganic compounds containing Al. Furthermore, the inorganic compound according to this embodiment contains an inorganic compound containing Si, i.e., the Si content (bulk) is SiO ２ It is necessary that the amount is in the range of 20% to 70% by mass in terms of conversion. Similar to inorganic compounds containing Al, in one aspect of this embodiment, silica (SiO ２ The following description assumes that the material contains silica, but this embodiment does not require that silica be included.

[0013] The Al content (bulk) of the inorganic compound according to this embodiment is preferably 35% by mass or more, more preferably 40% by mass or more. In this specification, the Al content (bulk) means the content of Al contained in the whole inorganic compound, which is calculated by converting it into Al ２ O ３ . When this Al content (bulk) increases, the pore volume tends to increase. When the pore volume is large, it can be suitably used as a material for catalysts and adsorbents. Further, this Al content (bulk) is preferably 75% by mass or less, more preferably 70% by mass or less. If this Al content (bulk) becomes too large, the pore volume tends to decrease in the presence of an acid. The upper and lower limits of this Al content (bulk) can be arbitrarily combined within the above-mentioned range. Further, the inorganic compound containing Al contained in the inorganic compound according to this embodiment is preferably pseudo-boehmite. When diffraction peaks derived from pseudo-boehmite appear in the X-ray diffraction pattern, it can be determined that pseudo-boehmite is included. Specifically, in the X-ray diffraction pattern, diffraction peaks are present at 2θ = 14° ± 1°, 28° ± 1°, 38° ± 1°, 49° ± 1° corresponding to the Miller indices (020), (021), (130), (150) planes of the boehmite structure, and if the crystallite size calculated from the peak of the Miller index (130) plane is 10 nm or less, it can be determined that pseudo-boehmite is included.

[0014] The inorganic compound according to this embodiment contains an inorganic compound containing Si, that is, the Si content (bulk) needs to be in the range of 20% to 70% by mass in terms of SiO ２ conversion. In this specification, the Si content (bulk) means the Si content contained in the whole inorganic compound, which is calculated by converting it into SiO ２This value is calculated by converting it to [amount]. In the inorganic compound according to this embodiment, the Si-containing inorganic compound is abundant on the surface of the pseudoboehmite, thereby suppressing the decrease in pore volume in the presence of acid. The Si content (bulk) of the inorganic compound according to this embodiment is preferably 25% by mass or more, and more preferably 30% by mass or more. When this Si content (bulk) is high, the pore volume does not decrease easily in the presence of acid. Pore volume is one of the factors that affect the performance of catalysts and adsorbents. Even if catalysts and adsorbents containing the inorganic compound according to this embodiment are manufactured or used in the presence of acid, the performance of the catalyst or adsorbent does not decrease easily. Furthermore, this Si content (bulk) is preferably 65% ​​by mass or less, and more preferably 60% by mass or less. When this Si content (bulk) is low, the pore volume tends to increase. The upper and lower limits of this Si content (bulk) can be combined in any way within the range described above. Furthermore, the Si-containing inorganic compound included in the inorganic compound according to this embodiment is preferably silica. The state of the silica may be crystalline or amorphous. If a material contains Si and a peak originating from silica appears in its X-ray diffraction pattern, it can be determined that it contains crystalline silica. Conversely, if a material contains Si but no silica peak appears in its X-ray diffraction pattern, it can be determined that it contains amorphous silica.

[0015] The inorganic compound according to this embodiment must have a Si content (near the surface) measured by X-ray photoelectron spectroscopy that is 60% or more of the Si content (bulk). This indicates that a large amount of silica is present on the surface of the pseudoboehmite. This percentage is preferably 70% or more, and more preferably 80% or more. Silica present on the surface of the pseudoboehmite has the effect of suppressing the decrease in pore volume in the presence of acid, and the more silica present there is, the more pronounced this suppression effect becomes. The upper limit of this percentage may be 120% or less, 110% or less, or 100% or less. The upper and lower limits of this percentage can be arbitrarily combined within the range described above.

[0016] The inorganic compound according to this embodiment must have a total pore volume in the range of 1.3 mL / g to 2.3 mL / g. In this specification, total pore volume refers to the sum of the volumes of all pores measured by the nitrogen adsorption method. This total pore volume is preferably 1.4 mL / g or more, and more preferably 1.5 mL / g or more. A larger total pore volume makes it more suitable for use as a catalyst or adsorbent material. The upper limit of the total pore volume may be 2.2 mL / g or less, 2.1 mL / g or less, or 2.0 mL / g or less. This upper and lower limit of the total pore volume can be arbitrarily combined within the aforementioned range.

[0017] In this embodiment, the inorganic compound preferably has a pore volume of 10 nm or larger that accounts for 50% or more of the total pore volume, more preferably 60% or more, and particularly preferably 70% or more. In this specification, the pore volume of 10 nm or larger refers to the sum of the volumes of pores with a diameter of 10 nm or larger, as measured by the nitrogen adsorption method. These pores of 10 nm or larger tend to be favorable reaction fields in catalytic and adsorption reactions, and also affect the diffusivity of reactants and products. When the proportion of such pore volume increases, catalytic activity tends to increase and the adsorption rate tends to improve. The upper limit of this proportion of pore volume of 10 nm or larger may be 100% or less, 90% or less, or 80% or less. The upper and lower limits of the total pore volume can be arbitrarily combined within the range described above.

[0018] The inorganic compound according to this embodiment has a spectrum obtained by Fourier transform infrared spectroscopy at 3730 cm⁻¹. －１ ~3760cm －１ The height of the absorption band peak (H1) appearing in this range, and 3630 cm －１ ~3670cm －１ The ratio (H1 / H2) of the peak height (H2) of the absorption band appearing in this range to the ratio (H1 / H2) is preferably 3.5 or higher, more preferably 4.0 or higher, and particularly preferably 4.5 or higher. 3730 cm －１ ~3760cm －１ The absorption peaks that appear originate from isolated silanol groups. Also, at 3630 cm⁻¹－１ ~3670cm －１ The absorption peaks appearing in this range originate from hydrogen-bonded silanol groups. A higher ratio of these heights (H1 / H2) makes the pore volume less susceptible to reduction in the presence of acid. The upper limit of this ratio may be 10 or less, 8 or less, or 6 or less. The upper and lower limits of this ratio can be arbitrarily combined within the aforementioned range.

[0019] The inorganic compound according to the embodiment has an alkali metal (M) content of M ２ The amount of oxygen (O) is preferably 1% by mass or less, more preferably 0.5% by mass or less, and particularly preferably 0.1% by mass or less. Among the alkali metals, it is especially preferable that the content of Na be within the aforementioned range. When the alkali metal content is low, the amount of solid acid tends to increase. When the amount of solid acid increases, it can adsorb basic substances well when used as an adsorbent. Furthermore, when used as a catalyst or catalyst material for reactions in which the active site is an acid site, the activity tends to increase.

[0020] In this embodiment, the inorganic compound preferably has a total content of components other than Al, Si, and alkali metals (M) of 3% by mass or less, more preferably 2% by mass or less, and particularly preferably 1% by mass or less, on an elemental basis. When the content of components other than Al, Si, and alkali metals (M) is reduced, the occurrence of unexpected side reactions can be suppressed when used as a material for catalysts, adsorbents, etc.

[0021] The inorganic compound according to this embodiment has a specific surface area of ​​400 m². ２ It is preferable that it be 415 m or more per g. ２ It is more preferable that it be 430m or more per gram. ２ It is particularly preferable that the specific surface area is 600 m² or more. A large specific surface area makes it suitable for use as a catalyst or adsorbent material. The upper limit of this specific surface area is 600 m². ２ It may be less than or equal to / g, and 585m ２ It may be less than or equal to / g, and 570m ２ It may be less than or equal to / g. The upper and lower limits of this specific surface area can be arbitrarily combined within the range described above.

[0022] The inorganic compound according to this embodiment is preferably a powder with an average particle size in the range of 1 μm to 100 μm, more preferably in the range of 5 μm to 95 μm, and particularly preferably in the range of 10 μm to 90 μm. When the average particle size is within the above range, handling is improved when used as a raw material for catalysts, adsorbents, etc. In particular, handling is improved when processing into molded catalysts, adsorbents, etc. The average particle size of the inorganic compound according to this embodiment refers to the median diameter (D50) calculated from the volume-based particle size distribution obtained using a laser diffraction / scattering particle size distribution analyzer.

[0023] The inorganic compound according to this embodiment can be suitably used as a support for catalysts, adsorbents, etc. It can also be suitably used as an inorganic binder. Furthermore, amorphous silica-alumina obtained by calcining the inorganic compound according to this embodiment can also be suitably used as a support for catalysts, adsorbents, etc. Amorphous silica-alumina refers to a material that contains Si and Al and in which peaks originating from silica, alumina, or zeolite cannot be confirmed in the X-ray diffraction pattern. Since amorphous silica-alumina exhibits solid acidity, it can be suitably used as a catalyst material for catalytic decomposition reactions and hydrogenation desulfurization reactions.

[0024] The inorganic compound according to this embodiment preferably contains more than 10 μmol / g of Brønsted acid, more preferably 15 μmol / g or more, and particularly preferably 20 μmol / g or more. When the amount of Brønsted acid is within the above range, catalytic activity is improved in catalytic reactions in which Brønsted acid acts as an active site. The upper limit of the amount of Brønsted acid is preferably 80 μmol / g or less, more preferably 50 μmol / g or less, and particularly preferably 30 μmol / g or less. When the amount of Brønsted acid is within the above range, catalytic reactions in which Brønsted acid acts as an active site for side reactions can be suppressed, and as a result, selectivity tends to improve. The upper and lower limits of the amount of Brønsted acid can be arbitrarily combined within the above range depending on the type of catalytic reaction.

[0025] The inorganic compound according to this embodiment preferably has a Lewis acid content of 50 μmol / g or more, more preferably 100 μmol / g or more, and particularly preferably 150 μmol / g or more. When the Lewis acid content is within the above range, catalytic activity is improved in catalytic reactions in which Lewis acids act as active sites. The upper limit of this Lewis acid content is preferably 450 μmol / g or less, more preferably 400 μmol / g or less, and particularly preferably 350 μmol / g or less. When the Lewis acid content is within the above range, catalytic reactions in which Lewis acids act as active sites for side reactions can be suppressed, and as a result, selectivity is improved. The upper and lower limits of this Lewis acid content can be arbitrarily combined within the above range depending on the type of catalytic reaction.

[0026] [Manufacturing method according to this embodiment] The manufacturing method according to this embodiment has a specific surface area of ​​350 m². ２ Pseudoboehmite and silica, each with a total pore volume of 1.5 mL / g or more and SiO2 ２ Al ２ O ３ In terms of the converted mass ratio, SiO ２ : Al ２ O ３ The process includes a mixing step of mixing in water to obtain a precursor slurry in a ratio of 20:80 to 70:30, and a maturation step of adjusting the isoelectric point of the precursor slurry to a range of 2.5 to 4.5 to obtain an inorganic compound.

[0027] The manufacturing method according to this embodiment has a specific surface area of ​​350 m². ２ Pseudoboehmite and silica, each with a total pore volume of 1.5 mL / g or more and SiO2 ２ Al ２ O ３ In terms of the converted mass ratio, SiO ２ : Al ２ O ３ It is necessary to have a mixing step in which a precursor slurry is obtained by mixing in water in a ratio of 20:80 to 70:30. In this step, the specific surface area is 350 m². ２It is preferable to mix an aqueous slurry containing pseudoboehmite in an amount of 1.5 mL / g or more and a total pore volume of 1.5 mL / g or more with an aqueous slurry containing silica. Hereinafter, "aqueous slurry" as used herein refers to a solution in which solid components such as pseudoboehmite and silica are dispersed in water.

[0028] In this mixing process, the specific surface area is 350 m². ２ It is preferable to use an aqueous slurry containing pseudoboehmite with a specific surface area of ​​600 m² or more and a total pore volume of 1.5 mL / g or more. By using an aqueous slurry containing pseudoboehmite with a large specific surface area and total pore volume, the total pore volume of the final inorganic compound tends to be large as well. ２ It may be less than / g, and 500m ２ It may be less than or equal to / g. The upper and lower limits of this specific surface area can be arbitrarily combined within the range described above. Furthermore, this total pore volume may be 3 mL / g or less, or 2.5 mL / g or less. The upper and lower limits of this total pore volume can be arbitrarily combined within the range described above.

[0029] An aqueous slurry containing pseudoboehmite can be prepared by mixing a basic aluminum aqueous solution and an acidic aluminum aqueous solution at a temperature of 50°C or lower to precipitate pseudoboehmite. At this time, it is preferable to adjust the amounts of basic aluminum aqueous solution and acidic aqueous solution added to swing the pH from basic to acidic and from acidic to basic. By using this method, an aqueous slurry containing pseudoboehmite with a large specific surface area and total pore volume can be prepared.

[0030] In this mixing step, the concentration of pseudoboehmite contained in the aqueous slurry containing pseudoboehmite is Al ２ O ３The concentration of pseudoboehmite is preferably 1% by mass or more, more preferably 3% by mass or more, and particularly preferably 5% by mass or more. Higher concentrations of pseudoboehmite tend to lead to higher production efficiency. Furthermore, the concentration of pseudoboehmite is preferably 20% by mass or less, more preferably 15% by mass or less, and particularly preferably 10% by mass or less. Lower concentrations of pseudoboehmite tend to result in a higher proportion of Si content (near the surface).

[0031] In this mixing step, it is preferable to use an aqueous slurry containing silica. The silica-containing aqueous slurry used in this mixing step can be prepared by conventionally known methods of mixing silica with water. For example, silica contained in silica sol or fumed silica can be mixed with water. In this case, the specific surface area should be 400 m². ２ It is preferable to use silica of 1 / g or more. Furthermore, the specific surface area should be 700 m². ２ It may be less than / g, and 600m ２ It may be less than or equal to / g. The upper and lower limits of this specific surface area can be arbitrarily combined within the range described above.

[0032] In this mixing step, the concentration of silica contained in the silica-containing aqueous slurry is SiO ２ The silica concentration is preferably 10% by mass or more, more preferably 15% by mass or more, and particularly preferably 20% by mass or more. Higher silica concentrations tend to lead to higher production efficiency. Furthermore, the silica concentration is preferably 45% by mass or less, more preferably 40% by mass or less, and particularly preferably 35% by mass or less. Lower silica concentrations tend to result in a higher proportion of Si content (near the surface).

[0033] In this mixing process, an aqueous slurry containing pseudoboehmite and an aqueous slurry containing silica are mixed using SiO2. ２ Al ２ O ３ In terms of the converted mass ratio, SiO ２ : Al ２ O ３It is necessary to mix them in a ratio of 20:80 to 70:30. This mass ratio is preferably 25:75 to 65:35, and more preferably 30:70 to 60:40. When the amount of silica is high (the amount of pseudoboehmite is low) in this mass ratio, the pore volume of the final inorganic compound does not decrease easily in the presence of acid. Conversely, when the amount of silica is low (the amount of pseudoboehmite is high), the pore volume of the final inorganic compound tends to be high.

[0034] In this mixing step, the solid content concentration in the precursor slurry is preferably 40% by mass or less, more preferably 30% by mass or less, and particularly preferably 20% by mass or less. This solid content concentration is the ratio of the mass of the residue obtained by removing water from the precursor slurry to the total mass of the precursor slurry. When this solid content concentration is low, the dispersibility of pseudoboehmite and silica in the precursor slurry tends to be good. This solid content concentration may be 1% by mass or more, 5% by mass or more, or 10% by mass or more. The upper and lower limits of this solid content concentration can be arbitrarily combined within the range described above.

[0035] The manufacturing method according to this embodiment requires a maturation step to obtain an inorganic compound by adjusting the isoelectric point of the precursor slurry to a range of 2.5 to 4.5. The purpose of this maturation step is to allow a large amount of silica to be present on the surface of the pseudoboehmite by adjusting the isoelectric point of the precursor slurry obtained in the aforementioned mixing step to a specific range. Factors that control this isoelectric point include the temperature of the precursor slurry, the pH of the precursor slurry, and the holding time. The temperature of the precursor slurry is preferably adjusted to a range of 40°C to 95°C. The pH of the precursor slurry is preferably adjusted to a range of 7 to 10. Furthermore, the holding time is not limited to a specific range, but is preferably held until it falls within the aforementioned isoelectric point range. The advantages of this method are not limited to the fact that a sufficient amount of silica can be present on the surface of the pseudoboehmite. Even if the properties and mixing ratio of the raw material silica and pseudoboehmite change, the amount of silica on the surface of the pseudoboehmite can be easily adjusted by using the isoelectric point of the precursor slurry as a reference.

[0036] The manufacturing method according to this embodiment preferably includes a separation step to separate the inorganic compound obtained in the maturation step from water to obtain a powdered inorganic compound. In this separation step, water can be removed by methods such as filtration, decantation, and drying. The drying temperature is preferably 350°C or lower, and more preferably 300°C or lower. Furthermore, spray drying is more preferable because it makes it easier to control the average particle size of the powdered inorganic compound within a specific range. In addition, the powdered inorganic compound obtained in the separation step may be subjected to unit operations such as washing, calcination, and molding as needed.

[0037] The inorganic compounds and their production methods according to this embodiment will be described in detail below using examples, but the present invention is not limited in any way by these examples.

[0038] [Analysis Method] The analysis of each sample obtained in the examples was performed by the following method.

[0039] (1) Isoelectric Point Measurement The isoelectric point of the precursor slurry was measured by pH titration using a Zetasizer Pro manufactured by Malvern Panalytical. For the measurement, a sample of the precursor slurry with a solid content concentration of 0.1% by mass was used. In addition, at least one of the following was used to adjust the pH: 0.1 mol / L HCl aqueous solution, 0.01 mol / L HCl aqueous solution, or 0.1 mol / L NaOH aqueous solution. Furthermore, the measurement interval was set so that the pH value was in increments of 0.5.

[0040] (2) Bulk composition analysis (2-1) Measurement of Si content and Al content The content (mass percentage) of each element Si and Al contained in the sample was measured using an X-ray fluorescence analyzer (manufactured by Rigaku Corporation, product name "RIX-3000"). The obtained content of each element was expressed as SiO ２ , and Al ２ O ３ The Si content and Al content were calculated by converting them to the equivalent values. (2-2) Measurement of Na content The Na content was measured using an atomic absorption spectrophotometer (Hitachi, Ltd., product name "Z-5300"). First, the sample was placed in a platinum crucible, sulfuric acid and hydrofluoric acid were added, and then it was heated and evaporated to dryness to obtain the solid. Next, hydrochloric acid and water were added to this solid, and after heating to dissolve, deionized water was added to dilute it and obtain a diluted solution. The Na concentration of this diluted solution was measured using the atomic absorption spectrophotometer described above, and this was converted to the content per gram of the sample to obtain the Na content (Na ２ The O equivalent was calculated.

[0041] (3) Compositional analysis near the surface (XPS measurement) The sample was placed on the sample stage and X-ray photoelectron spectroscopy (XPS) was performed under the following conditions. The obtained spectra were analyzed to calculate the Si content (near the surface) and Al content (near the surface). Si2p: 103.5 eV ± 3 eV Al2p: 74.5 eV ± 3 eV <Measurement conditions> For XPS measurement, a Shimadzu KRATOS ULTRA2 (X-ray source: monochromatic Al Kα rays) was used. The measurements were performed under the following conditions: acceleration voltage 15 kV, emission current 15 mA, and scan counts of Si (Si2p) 10 times, Al (Al2p) 10 times, C (C1s) 15 times, and O (O1s) 3 times. The obtained spectra were corrected so that the C-C bond of C1S was 284.8 eV. <Calculation Conditions> The analysis software "ESCAPe" included with the instrument was used to analyze the corrected spectrum. Peaks originating from Si and Al in the spectrum were identified, and the concentrations near the surface of Si and Al were calculated from the area of ​​each peak. These concentrations were then converted to SiO2. ２ Al ２ O ３ The Si content (near the surface) and Al content (near the surface) were calculated by converting them to this value.

[0042] (4) Measurement of pore volume (4-1) Method for measuring the pore volume of the raw material, pseudo-boehmite The pore distribution of the sample was measured using BELSORP-mini Ver2.5.6 manufactured by Microtrac-Bell Co., Ltd. Specifically, nitrogen gas was adsorbed onto the sample, which had been heat-treated at 110°C for 1 hour under vacuum evacuation, and the pore distribution was determined from the desorption side isotherm of the relative pressure (P / P0 = 0.99) in the BJH method. From this pore distribution, the total volume of pores with a diameter in the range of 2.4 nm to 192.4 nm was defined as the total pore volume.

[0043] (4-2) Method for measuring the total pore volume and pore volume of pores larger than 10 nm of inorganic compounds Approximately 30 mL of the sample was placed in a porcelain crucible (Type B-2), heated at 600°C for 2 hours, and then cooled to room temperature in a desiccator to obtain a sample for measurement. The pore distribution of the sample was measured using BELSORP-mini Ver2.5.6 manufactured by Microtrac-Bell Co., Ltd. Specifically, nitrogen gas was adsorbed onto the sample for measurement, which had been heat-treated at 500°C for 1 hour under vacuum evacuation, and the pore distribution was determined from the desorption side isotherm of the relative pressure (P / P0 = 0.99) of the BJH method. From this pore distribution, the pore volume of pores with a diameter in the range of 2.4 nm to 192.4 nm was defined as the total pore volume, and the pore volume of pores with a diameter of 10 nm to 192.4 nm was defined as the pore volume of pores larger than 10 nm, and these were calculated accordingly. Furthermore, the percentage of pore volumes larger than 10 nm was calculated using the following formula: Percentage of pore volumes larger than 10 nm [%] = Pore volume larger than 10 nm / Total pore volume × 100

[0044] (5) Surface condition analysis (FT-IR) Approximately 30 mL of the sample was taken into a porcelain crucible (Type B-2), heated at 600°C for 2 hours, and then cooled to room temperature in a desiccator to obtain the sample for measurement. 25 mg of this sample was formed into a φ20 mm pellet. This pellet was placed in an IN-SITU cell for spectroscopy at Makuhari Chemical Glass Works and subjected to high vacuum (10°C). －３ Vacuum heating pretreatment was performed at 500°C for 1 hour under conditions of Pa or less. After cooling the IN-SITU cell to 50°C, Fourier transform infrared spectroscopy (FT-IR) measurements were performed using a JASCO FT / IR-6100 under the following conditions. In addition, to ensure high-precision measurements, water vapor and carbon dioxide in the measurement optical path were removed, and high-purity nitrogen gas was supplied to the interference chamber, sample chamber, and detector chamber of the FT-IR during the measurement. Detector: TGS Resolution: 2.0 cm －１ Measurement range: 4,000–3,000 cm －１ Number of integrations: For spectra obtained 100 times, 4,000 cm⁻¹ －１ Absorbance at 3,000 cm² －１A baseline was established by a two-point correction, connecting the absorbance at 3730 cm⁻¹ with a straight line. After measurement, the pellet was removed from the IN-SITU cell and its weight was measured. This post-measurement weight was used to perform weight correction of the spectrum. －１ ~3760cm －１ The peak height (H1) of the absorption band (isolated silanol group) having a maximum in the range of 3630 cm －１ ~3670cm －１ The peak height (H2) of the absorption band (hydrogen-bonded silanol group) with a maximum in the range was measured, and its ratio (H1 / H2) was calculated. －１ ~3760cm －１ Range and 3630 cm －１ ~3670cm －１ If there were multiple peaks within the range, the peak height of the peak with the highest peak height was adopted as the peak height for each absorption band.

[0045] (6-1) Measurement of specific surface area (boehmite used as raw material) Approximately 30 mL of the sample was taken into a porcelain crucible (Type B-2), heated at 110°C for 1 hour, and then cooled to room temperature in a desiccator to obtain a sample for measurement. Next, 1 g of the sample was taken and the specific surface area of ​​the sample was measured using the BET one-point method with a fully automatic surface area analyzer (MultiSorb 12, manufactured by Yuasa Ionics Co., Ltd.).

[0046] (6-2) Measurement of specific surface area (inorganic compounds) Approximately 30 mL of the sample was placed in a porcelain crucible (Type B-2), heated at 600°C for 2 hours, and then cooled to room temperature in a desiccator to obtain a sample for measurement. Next, 1 g of this sample was taken, and the specific surface area was measured using a fully automated surface area analyzer (MultiSorb 12, manufactured by Yuasa Ionics Co., Ltd.) by the BET single-point method.

[0047] (7) X-ray diffraction measurement (identification of pseudoboehmite) The sample to be measured was ground in a mortar and then packed into a sample cell to obtain the measurement sample. Next, the X-ray diffraction pattern of the measurement sample was measured using a MiniFlex manufactured by Rigaku Corporation. The measurement conditions were as follows. Operating axis: 2θ / θ Radiation source: CuKα Measurement method: Continuous Voltage: 40kV Current: 15mA Measurement start angle: 2θ = 5° Measurement end angle: 2θ = 80° Sampling width: 0.020° Scan speed: 10.000° / min In the obtained X-ray diffraction pattern, if diffraction peaks exist at 2θ = 14°±1°, 28°±1°, 38°±1°, and 49°±1°, corresponding to the Miller indices (020), (021), (130), and (150) planes of the boehmite structure, and the crystallite size calculated from the peak of the Miller index (130) plane is 10 nm or less, it was determined that pseudoboehmite was present.

[0048] (8) Acid resistance evaluation The sample was suspended in pure water to prepare 100 g of slurry with a solid content concentration of 10% by mass. This slurry was stirred and mixed at 80°C for 20 minutes. Then, 5 g of 60% nitric acid was added and the slurry was acid-treated at 80°C for 60 minutes. The slurry after acid treatment was filtered and washed with 50 g of pure water at 60°C to obtain a washed cake. This washed cake was dried overnight at 110°C to obtain a dried product. The obtained dried product was ground in a mortar and used as the measurement sample, and the total pore volume and the pore volume of pores larger than 10 nm were measured by the method in (4-2) above, and the specific surface area was measured by the method in (6-2) above. The solid content concentration was determined from the mass of the residue obtained after heating the slurry at 1000°C for 1 hour.

[0049] (9) Measurement of Brønsted acid and Lewis acid amounts A 50 mg sample was molded into a circular disc with a diameter of 20 mm. The molded disc was placed in an infrared absorption measurement cell (hereinafter referred to as "IR cell") connected to a vacuum line and subjected to vacuum evacuation treatment for 1 hour while heated to 500°C. After that, the temperature inside the IR cell was lowered to 150°C, and the infrared absorption spectrum of the disc was measured using a JASCO FT / IR-4600. The measurement conditions were as follows: Detector: TGS Resolution: 2.0 cm －１ Measurement range: 1,700–1,400 cm －１Number of cumulative measurements: 100 Next, pyridine was introduced into the IR cell and subjected to vacuum evacuation treatment at 150°C for 10 minutes. The infrared absorption spectrum of the disc with adsorbed pyridine was then measured in the same manner. A difference spectrum was created by subtracting the spectrum before pyridine introduction from the obtained spectrum after pyridine adsorption, and the area of ​​the absorption peaks attributed to the Brønsted acid site (B) and Lewis acid site (L) in the difference spectrum was calculated. Based on the calculated absorption peak area, the amount of Brønsted acid and Lewis acid was calculated according to the method described in the literature by C. A. Emeis et al. (J. Catal., 141, 347-354, 1993).

[0050] [Ingredients] Sodium gluconate aqueous solution: 25% by mass concentration Sodium aluminate aqueous solution: Al ２ O ３ Converted concentration 22% by mass Aluminum sulfate aqueous solution: Al ２ O ３ Converted concentration 7% by mass Ammonia water: concentration 15% by mass Pseudoboehmite 1: specific surface area 370 m² ２ / g, total pore volume 1.8 mL / g, crystallite size 2.5 nm. Pseudoboehmite 2: specific surface area 441 m². ２ / g, total pore volume 2.2 mL / g, crystallite size 2.2 nm. Pseudoboehmite 3: specific surface area 320 m². ２ / g, total pore volume 0.65 mL / g, crystallite size 2.8 nm. Silica: average particle size 12 μm, specific surface area 480 m². ２ / g Silica slurry: SiO ２ Conversion concentration 33% by mass

[0051] [Preparation of Boehmite 1] 120 kg of warm water at 50°C was filled into a 200 L tank with a steam jacket, and the state of stirring at 50°C was maintained. 249 g of an aqueous sodium gluconate solution was added to this warm water. Then, 1.77 kg of an aqueous sodium aluminate solution was added to this warm water and held for 5 minutes. Further, 2.95 kg of an aqueous aluminum sulfate solution was added to this warm water and held for 5 minutes to prepare a boehmite 1 precursor slurry. To this boehmite 1 precursor slurry, 16.10 kg of an aqueous sodium aluminate solution and 29.80 kg of an aqueous aluminum sulfate solution were simultaneously added over 40 minutes and held for 5 minutes. 3.85 kg of an aqueous sodium aluminate solution was added to this boehmite 1 precursor slurry and held for 2 hours. 0.53 kg of aqueous ammonia was added to this boehmite 1 precursor slurry and held for 5 minutes. Then, the boehmite 1 precursor slurry was dehydrated with a plate filter to separate the solid content. This solid content was washed with running water using warm water at 60°C to obtain a washed cake. This washed cake was dispersed in water to obtain a boehmite 1 slurry (corresponding to an aqueous slurry containing boehmite) with an Al ２ O ３ equivalent concentration of 7.2 mass%. For the solid content obtained by freeze-drying this boehmite 1 slurry (aqueous slurry containing boehmite), the above-mentioned (6-1) specific surface area measurement, (4-1) pore size distribution measurement, and (7) X-ray diffraction measurement were performed. As a result, the specific surface area was 370 m ２ / g, the total pore volume was 1.8 mL / g, and it was confirmed that boehmite was formed.

[0052] [Preparation of Boehmite 2] A boehmite 2 slurry (corresponding to an aqueous slurry containing boehmite) was obtained in the same manner as the preparation of boehmite 1, except that 120 kg of warm water at 40°C was filled and the state of stirring at 40°C was maintained. For the solid content obtained by freeze-drying this boehmite 2 slurry (aqueous slurry containing boehmite), the above-mentioned (6-1) specific surface area measurement, (4-1) pore size distribution measurement, and (7) X-ray diffraction measurement were performed. As a result, the specific surface area was 441 m ２ / g, the total pore volume was 2.2 mL / g, and it was confirmed that boehmite was formed.

[0053] [Preparation of Pseudoboehmite 3] Pseudoboehmite 3 slurry (equivalent to an aqueous slurry containing pseudoboehmite) was obtained in the same manner as the preparation of pseudoboehmite 1, except that 120 kg of 60°C hot water was filled and stirred at 60°C, and 48 g of sodium gluconate aqueous solution was added. The solid content obtained by freeze-drying this pseudoboehmite 3 slurry (aqueous slurry containing pseudoboehmite) was subjected to the aforementioned (6-1) specific surface area measurement, (4-1) pore distribution measurement, and (7) X-ray diffraction measurement. As a result, the specific surface area was 320 m². ２ The concentration was 0.65 mL / g, and the total pore volume was 0.65 mL / g, confirming the formation of pseudoboehmite.

[0054] [Preparation of silica slurry: SiO ２ [Concentration 33% by mass] Silica was suspended in water to obtain a silica slurry (equivalent to an aqueous slurry containing silica) with a silica concentration of 33% by mass.

[0055] [Example 1] 22.44 kg of pseudo-boehmite slurry was mixed with 0.27 kg of ammonia water and stirred for 5 minutes. 3.27 kg of silica slurry was mixed with this pseudo-boehmite slurry to obtain a precursor slurry. At this time, the isoelectric point of the precursor slurry was 8.9. This precursor slurry was aged at 70°C while stirring, and the aging was stopped when the isoelectric point of the particles contained in the precursor slurry became 3.0. Subsequently, the precursor slurry was dispersed in a homogenizer, and the particles were separated by spray drying (inlet temperature: 270°C, outlet temperature: 130°C) to obtain an inorganic compound. The obtained inorganic compound was used as a measurement sample, and the analyses and evaluations described in (2) to (8) above were performed. The preparation conditions and the results of the analysis and evaluation are shown in Tables 1 to 3, respectively. Furthermore, the FT-IR spectrum obtained in the measurement described in (5) above is shown in Figure 1. In addition, the difference spectrum obtained in the measurement described in (9) above is shown in Figure 2.

[0056] [Example 2] An inorganic compound was obtained in the same manner as in Example 1, except that the precursor slurry was aged at 50°C while being stirred, and the aging was stopped when the isoelectric point of the particles contained in the precursor slurry reached 3.7. The obtained inorganic compound was used as a measurement sample, and the analysis and evaluation described in (2) to (8) above were performed. The preparation conditions and the results of the analysis and evaluation are shown in Tables 1 to 3, respectively.

[0057] [Example 3] An inorganic compound was obtained in the same manner as in Example 1, except that the precursor slurry was aged while being stirred at 90°C, and the aging was stopped when the isoelectric point of the particles contained in the precursor slurry reached 2.7. The obtained inorganic compound was used as a measurement sample, and the analysis and evaluation described in (2) to (8) above were performed. The preparation conditions and the results of the analysis and evaluation are shown in Tables 1 to 3, respectively.

[0058] [Example 4] An inorganic compound was obtained in the same manner as in Example 1, except that the amount of ammonia water added was 0.54 kg and maturation was terminated when the isoelectric point of the particles contained in the precursor slurry reached 2.9. The obtained inorganic compound was used as a measurement sample, and the analysis and evaluation described in (2) to (8) above were performed. The preparation conditions and the results of the analysis and evaluation are shown in Tables 1 to 3, respectively.

[0059] [Example 5] An inorganic compound was obtained in the same manner as in Example 1, except that the amount of pseudo-boehmite 1 slurry used was 26.18 kg, the amount of silica slurry added was 2.45 kg, and maturation was stopped when the isoelectric point of the particles contained in the precursor slurry reached 3.7. The obtained inorganic compound was used as a measurement sample, and the analysis and evaluation described in (2) to (8) above were performed. The preparation conditions and the results of the analysis and evaluation are shown in Tables 1 to 3, respectively.

[0060] [Example 6] 15.00 kg of pseudo-boehmite slurry was mixed with 0.27 kg of ammonia water and stirred for 5 minutes. 4.91 kg of silica slurry and 6.05 kg of pure water were mixed with this pseudo-boehmite slurry to obtain a precursor slurry. This precursor slurry was aged at 70°C while stirring, and the aging process was terminated when the isoelectric point of the particles contained in the precursor slurry reached 3.2°C. The subsequent steps were carried out in the same manner as in Example 1 to obtain the inorganic compound. The obtained inorganic compound was used as a sample for analysis and evaluation according to (2) to (8) above. The preparation conditions and the results of the analysis and evaluation are shown in Tables 1 to 3, respectively.

[0061] [Example 7] An inorganic compound was obtained in the same manner as in Example 1, except that the pseudo-boehmite 1 slurry was changed to pseudo-boehmite 2 slurry, and maturation was terminated when the isoelectric point of the particles contained in the precursor slurry reached 3.2. The obtained inorganic compound was used as a measurement sample, and the analysis and evaluation described in (2) to (8) above were performed. The preparation conditions and the results of the analysis and evaluation are shown in Tables 1 to 3, respectively.

[0062] [Example 8] An inorganic compound was obtained in the same manner as in Example 1, except that the amount of ammonia water added was changed to 1.35 kg and maturation was terminated when the isoelectric point of the particles contained in the precursor slurry reached 4.1. The obtained inorganic compound was used as a sample for analysis and evaluation as described in (2) to (8) above. The preparation conditions and the results of the analysis and evaluation are shown in Tables 1 to 3, respectively.

[0063] [Comparative Example 1] An inorganic compound was obtained in the same manner as in Example 1, except that the amount of ammonia water added was 0.08 kg and maturation was terminated when the isoelectric point of the particles contained in the precursor slurry reached 7.3. The obtained inorganic compound was used as a measurement sample, and the analysis and evaluation described in (2) to (8) above were performed. The preparation conditions and the results of the analysis and evaluation are shown in Tables 1 to 3, respectively.

[0064] [Comparative Example 2] An inorganic compound was obtained in the same manner as in Example 1, except that the amount of pseudo-boehmite 1 slurry used was 33.75 kg, the amount of silica slurry added was 0.81 kg, and maturation was terminated when the isoelectric point of the particles contained in the precursor slurry together with the silica reached 6.9. The obtained inorganic compound was used as a measurement sample, and the analysis and evaluation described in (2) to (8) above were performed. The preparation conditions and the results of the analysis and evaluation are shown in Tables 1 to 3, respectively.

[0065] [Comparative Example 3] 0.27 kg of aqueous ammonia was added to 7.50 kg of pseudo-boehmite slurry and stirred for 5 minutes. 6.54 kg of silica slurry and 11.67 kg of pure water were mixed with this pseudo-boehmite slurry to obtain a precursor slurry. This precursor slurry was aged at 70°C while stirring, and the aging was terminated when the isoelectric point of the particles contained in the precursor slurry reached 3.1. The subsequent steps were carried out in the same manner as in Example 1 to obtain the inorganic compound. The obtained inorganic compound was used as a measurement sample, and the analysis and evaluation described in (2) to (8) above were performed. The preparation conditions and the results of the analysis and evaluation are shown in Tables 1 to 3, respectively.

[0066] [Comparative Example 4] 22.44 kg of pseudo-boehmite 3 slurry was mixed with 0.08 kg of aqueous ammonia and stirred for 5 minutes. 3.27 kg of silica slurry was mixed with this pseudo-boehmite 3 slurry to obtain a precursor slurry. This precursor slurry was aged at 50°C while stirring, and the aging was stopped when the isoelectric point of the particles contained in the precursor slurry reached 6.4°C. The inorganic compound was obtained in the same manner as in Example 1 from the subsequent steps. The obtained inorganic compound was used as a measurement sample, and the analysis and evaluation described in (2) to (8) above were performed. The preparation conditions and the results of the analysis and evaluation are shown in Tables 1 to 3, respectively.

[0067]

[0068]

[0069]

[0070] The inorganic compounds of Comparative Examples 1 to 4 showed a low retention rate of pore volume of 15.3% to 66.4% in the presence of an acid, while the inorganic compounds of Examples 1 to 8 were found to have a high retention rate of pore volume of 89.1% to 99.5% even in the presence of an acid. Similar tendencies were also observed for the pore volume and specific surface area of 10 nm or more.

[0071] [Catalysis] The inorganic compound prepared in Example 1, alumina sol, and ultrastable Y-type zeolite (USY) were mixed at the following mixing ratios. Inorganic compound: 80% by mass (in terms of oxide) Alumina sol: 15% by mass (in terms of Al ２ O ３ conversion) USY: 5% by mass (in terms of oxide) Ion-exchanged water was added to these mixtures, and kneaded with a double-arm kneader to obtain a kneaded product. The obtained kneaded product was molded into a columnar shape with a diameter of 1.6 mm using an extrusion molding machine. The obtained molded body was dried at 110 °C and then fired in an electric furnace at a temperature of 550 °C for 3 hours to obtain a carrier.

[0072] Next, 288 g of an aqueous ammonium metatungstate solution (manufactured by Nippon Shinyaku Co., Ltd.; WO ３ concentration 50% by mass) and 84 g of nickel(II) nitrate hexahydrate (manufactured by Fujifilm Wako Pure Chemical Corporation; NiO concentration 26% by mass) were suspended in 200 ml of ion-exchanged water, and this was stirred at 25 °C for 30 minutes to prepare an impregnation solution. The obtained impregnation solution was spray-impregnated onto 400 g of the aforementioned carrier, dried at 250 °C, and fired in an electric furnace at a firing temperature of 550 °C for 1 hour to obtain a hydrocracking catalyst A. Further, a hydrocracking catalyst B was prepared in the same manner except that the inorganic compound prepared in Example 1 was changed to the inorganic compound prepared in Example 7. Furthermore, a hydrocracking catalyst C was prepared in the same manner except that the inorganic compound prepared in Example 1 was changed to the inorganic compound prepared in Comparative Example 4.

[0073] [Catalytic activity evaluation] MoO ３A reaction tube filled with a pretreatment catalyst containing 20% ​​by mass of 20% by mass of 20% by mass of 20% by mass of 20% by mass of 20% by mass of 2% －１ Under conditions of a hydrogen / oil ratio of 250 NL / L, the catalyst was pre-sulfurized for more than 8 hours. Subsequently, the hydrocracking performance was evaluated using VGO with the following properties as the feedstock oil, in the presence of hydrogen, under the reaction conditions shown below.

[0074] (Properties of the raw material oil) Raw material oil: Vacuum-reduced diesel oil Density at 15°C: 0.9268 g / cm³ ３ Sulfur content: 2.8550 mass% Nitrogen content: 820 mass ppm

[0075] (Reaction conditions) Reaction temperature: 375°C (1st to 2nd day after start of operation) 385°C (3rd day after start of operation) 395°C (4th day after start of operation) 405°C (5th day after start of operation) Liquid space velocity: 0.50 hr －１ Hydrogen pressure: 13.5 MPa Hydrogen / oil ratio: 1000 NL / L

[0076] Based on the evaluation results, the decomposition rate was determined by formula (1) below, and the middle distillate selectivity was determined by formula (2) below. Table 4 shows the relative decomposition rate and middle distillate selectivity when the decomposition rate of hydrocracking catalyst C is set to 100. Formula (1): Decomposition rate (%) = {(Content of fractions with boiling points higher than 360°C in the raw oil (mass%) - Content of fractions with boiling points higher than 360°C in the produced oil (mass%)) / Content of fractions with boiling points higher than 360°C in the raw oil (mass%)} × 100 Formula (2): Middle distillate selectivity (%) = (Content of fractions with boiling points between 145°C and 360°C in the produced oil when the decomposition rate is 70% (mass%) / 70) × 100

[0077]

[0078] Hydrocracking catalysts A and B showed superior decomposition rates and excellent middle distillate selectivity compared to hydrocracking catalyst C. This is thought to be because the use of a support containing an inorganic compound that is less susceptible to deterioration in the presence of acid suppressed deterioration even when exposed to acid (impregnation solution) during the catalytic process. Furthermore, since Brønsted acid sites are involved in the catalytic reaction, the large amount of Brønsted acid is also thought to have had an effect.

[0079] This disclosure includes the following items (1) to (8): (1) Al content (bulk) is Al ２ O ３ The Si content (bulk) is in the range of 30% to 80% by mass, and is SiO ２ An inorganic compound having a Si content in the range of 20% to 70% by mass, a total pore volume in the range of 1.3 mL / g to 2.3 mL / g, and a Si content (near the surface) measured by X-ray photoelectron spectroscopy that is 60% or more of the Si content (bulk). (Item 2) In the absorption spectrum obtained by Fourier transform infrared spectroscopy, at 3730 cm⁻¹ －１ ~3760cm －１ The height of the absorption band peak (H1) appearing in this range, and 3630 cm －１ ~3670cm －１ The inorganic compound described in item (1) above, wherein the ratio (H1 / H2) of the peak height (H2) of the absorption band appearing in the range is 3.5 or more. (Item 3) The inorganic compound described in item (1) or (2) above, wherein the proportion of pore volume of 10 nm or more is 50% or more of the total pore volume. (Item 4) The specific surface area is 400 m ２ / g ~ 600m ２(Item 5) An inorganic compound according to any one of the above items (1) to (3), having a Brønsted acid content in the range of 10 μmol / g and 80 μmol / g or less. (Item 6) An inorganic compound according to any one of the above items (1) to (5), having a Lewis acid content in the range of 50 μmol / g or more and 450 μmol / g or less. (Item 7) An inorganic compound according to any one of the above items (1) to (6), containing pseudoboehmite and silica. (Item 8) A specific surface area of ​​350 m ２ Pseudoboehmite and silica, each with a total pore volume of 1.5 mL / g or more and SiO2 ２ Al ２ O ３ In terms of the converted mass ratio, SiO ２ : Al ２ O ３ A method for producing an inorganic compound, comprising: a mixing step of mixing in water to obtain a precursor slurry in a ratio of 20:80 to 70:30; and a maturation step of adjusting the isoelectric point of the precursor slurry to a range of 2.5 to 4.5 to obtain an inorganic compound.

[0080] This application claims priority based on Japanese Patent Application No. 2024-185917, filed on 22 October 2024, and incorporates all of its disclosures herein.

Claims

1. Al content (bulk) is Al ２ O ３ The Si content (bulk) is in the range of 30% to 80% by mass, and is SiO ２ An inorganic compound having a Si content in the range of 20% to 70% by mass (converted to a different value), a total pore volume in the range of 1.3 mL / g to 2.3 mL / g, and a Si content (near the surface) measured by X-ray photoelectron spectroscopy that is 60% or more of the Si content (bulk).

2. In the absorption spectrum obtained by Fourier transform infrared spectroscopy, 3730 cm⁻¹ －１ ~3760cm －１ The height of the absorption band peak (H1) appearing in this range, and 3630 cm －１ ~3670cm －１ The inorganic compound according to claim 1, wherein the ratio (H1 / H2) of the peak height (H2) of the absorption band appearing in the range is 3.5 or more.

3. The inorganic compound according to claim 1, wherein the proportion of pore volumes of 10 nm or larger is 50% or more of the total pore volume.

4. The inorganic compound according to claim 1, having a specific surface area in the range of 400 m ２ / g to 600 m ２ / g.

5. The inorganic compound according to claim 1, wherein the amount of Brønsted acid is in the range of more than 10 μmol / g and 80 μmol / g or less.

6. The inorganic compound according to claim 1, wherein the Lewis acid content is in the range of 50 μmol / g or more and 450 μmol / g or less.

7. An inorganic compound according to any one of claims 1 to 6, comprising pseudoboehmite and silica.

8. Specific surface area of ​​350 m² ２ Pseudoboehmite and silica, each with a total pore volume of 1.5 mL / g or more and SiO2 ２ Al ２ O ３ In terms of the converted mass ratio, SiO ２ : Al ２ O ３ A method for producing an inorganic compound, comprising: a mixing step of mixing in water to obtain a precursor slurry in a ratio of 20:80 to 70:30; and a maturation step of adjusting the isoelectric point of the precursor slurry to a range of 2.5 to 4.5 to obtain an inorganic compound.

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