Amorphous silica-alumina

Abstract

The purpose of the present invention is to provide at least one among: an amorphous silica-alumina with which high catalytic activity can be expressed and with which a hydrocracking reaction of a long-chain paraffin, when an active metal element is included, can be limited to primary cracking in a highly efficient manner; and a method for producing the same.

Description

Amorphous Silica Alumina

[0001] The present disclosure relates to amorphous silica-alumina.

[0002] In the hydrocracking of long-chain paraffins using a bifunctional catalyst, if the catalyst's hydrogenation ability is low and its acidity is too high, repeated cleavage of carbon bonds occurs, resulting in an increase in the production of hydrocarbons with one to four carbon atoms and a decrease in the production of hydrocarbons with five or more carbon atoms that can be used for liquid fuels (hereinafter referred to as "overcracking"). On the other hand, if the catalyst's acidity is insufficient, the reaction remains isomerization and the cracking reaction does not proceed. Because it is difficult to control the degree of overcracking, in order to improve the selectivity of hydrocarbons with specific carbon numbers, such as gasoline and middle distillates (kerosene + diesel), it is necessary to control the cracking reaction so that it occurs only once, a process known as primary cracking.

[0003] Hydrocracking catalysts using amorphous silica-alumina as a catalyst support and supporting an active metal element of Groups 8 to 10 on the support have been reported. Amorphous silica-alumina is generally produced by a sol-gel method, a coprecipitation method, or the like. For example, Patent Document 1 discloses a method in which an acidic silica sol is mixed with an acidic aluminum source to prepare a silica-alumina sol, which is then neutralized with basic ammonium water to precipitate a silica-alumina gel. Furthermore, Patent Document 2 discloses a method in which a basic silica-alumina sol is prepared, which is then instantaneously mixed with sulfuric acid to acidify the solution, which is then neutralized with basic ammonium water.

[0004] JP 2022-284520 A JP 2018-083723 A

[0005] Fuel, Volume 279, page 118487.

[0006] The amorphous silica-alumina disclosed in Patent Documents 1 and 2 has large pores with an average pore diameter of 2 nm or more. Metal particles present in large pores are less spatially restricted, which makes metal sintering more likely to occur, and the hydrogenation ability of the catalyst derived from the active metal element decreases. When the hydrogenation ability decreases, the cracking activity of the catalyst decreases, and the cracking reaction does not stop at primary cracking, but rather occurs over-cracking.

[0007] The present disclosure aims to provide at least one of an amorphous silica-alumina that, when carrying an active metal element, can control the hydrocracking reaction of long-chain paraffins to primary cracking with high efficiency and can also exhibit high catalytic activity, a method for producing the same, and a paraffin reforming catalyst containing the same.

[0008] The present inventors have investigated the pore structure of amorphous silica-alumina in order to control the hydrocracking reaction of long-chain paraffins. As a result, they have found that amorphous silica-alumina, which has a specific pore structure and a large specific surface area for nitrogen adsorption, is an excellent catalyst carrier that can control the hydrocracking reaction to primary decomposition with high efficiency when an active metal element is contained therein, and also exhibits high catalytic activity.

[0009] That is, the present invention is as described in the claims, and the gist of the present disclosure is as follows: [1] A porous silica nanoparticle having a specific surface area of ​​280 m2, wherein the ratio of the pore volume of pores having a diameter of 0 nm to 2 nm to the pore volume of pores having a diameter of 0 nm to 10 nm is 60% or more, and ２ / g or more. [2] Amorphous silica-alumina having a total pore volume of 0.2 cm ３ / g or more. [3] The amorphous silica-alumina according to the above [1] or [2], wherein the molar ratio of silica to alumina is 10 or more and 100 or less. [4] The amorphous silica-alumina according to any one of the above [1] to [3], wherein the acid amount is 0.3 mmol / g or more. [5] The amorphous silica-alumina according to any one of the above [1] to [4], wherein the ratio of the area intensity of a peak having a peak top at a chemical shift of 40 ppm to 60 ppm to the sum of the area intensity of a peak having a peak top at a chemical shift of 40 ppm to 60 ppm and the area intensity of a peak having a peak top at a chemical shift of -10 ppm to 10 ppm is 0.40 or more and less than 0.80. [6] The amorphous silica-alumina according to any one of the above [1] to [5], wherein the amorphous silica-alumina contains one or more elements selected from the group consisting of Groups 8, 9, and 10. [7] A method for producing amorphous silica-alumina according to any one of [1] to [6] above, comprising: a gelling step of mixing a solution containing an alumina source, an acid source, and water, and a solution containing a basic silica source and water, with an aqueous sulfate solution containing an alkali metal to obtain an amorphous silica-alumina gel; an ion exchange step of ion-exchanging the amorphous silica-alumina gel; and a calcination step of calcining the amorphous silica-alumina gel obtained after the ion exchange step. [8] The production method according to [7] above, wherein the aqueous sulfate solution containing an alkali metal is an aqueous solution of one or more selected from the group consisting of lithium sulfate, sodium sulfate, and potassium sulfate. [9] A catalyst for paraffin reforming comprising the amorphous silica-alumina according to any one of [1] to [6] above.

[10] A method for reforming paraffins, comprising a step of contacting the paraffin-containing hydrocarbon fluid with the paraffin reforming catalyst according to [9] above.

[0010] The present disclosure aims to provide at least one of an amorphous silica-alumina that, when containing an active metal element, can control the hydrocracking reaction of long-chain paraffins to primary cracking with high efficiency and can also exhibit high catalytic activity, and a method for producing the same.

[0011] The amorphous silica-alumina of the present disclosure will be described below with an example of embodiment.In the present disclosure, each configuration and parameter disclosed in this specification includes any combination, and the upper and lower limits of the values ​​disclosed in this specification include any combination.The terms in this embodiment are as follows:

[0012] "Amorphous silica-alumina" is an amorphous compound containing at least aluminum (Al), silicon (Si), and oxygen (O). The fact that the amorphous silica-alumina of this embodiment is an amorphous compound can be determined from its powder X-ray diffraction (hereinafter also referred to as "XRD") pattern. In an XRD pattern, one having a crystalline XRD peak is a "crystalline aluminosilicate," and one not having a crystalline XRD peak is an "amorphous silica-alumina." Specifically, if the XRD pattern of the amorphous silica-alumina of this embodiment obtained under the following conditions does not have a diffraction peak with a full width at half maximum (FWHM) of less than 1.0 in the range of 2θ = 10° or more and 50° or less, the amorphous silica-alumina of this embodiment can be determined to be amorphous.

[0013] The XRD pattern can be measured using a general powder X-ray diffractometer (for example, Ultima IV Protectus, manufactured by Rigaku Corporation). The XRD pattern can be obtained by XRD measurement under the following conditions.

[0014] Accelerating current / voltage: 10 mA / 30 kV Radiation source: CuKα radiation (λ=1.54178 Å) Measurement mode: Continuous scan Scan conditions: 2° / min Measurement range: 2θ=10 to 70° Scattering slit: 1 / 3° Divergence slit: 1 / 3° Receiving slit: 0.3 mm Filter: Ni filter The "specific surface area" can be determined by measurement in accordance with JIS Z 8830:2013. That is, the specific surface area of ​​amorphous silica-alumina can be measured by a single-point method using the nitrogen adsorption method described above.

[0015] "Decane" refers to at least one of straight-chain decane (n-decane) and branched-chain decane (iso-decane).

[0016] "Cracking" refers to the decomposition of decane into hydrocarbons having 1 to 9 carbon atoms (hereinafter also referred to as "Cn" (where n is the number of carbon atoms in the hydrocarbon)).

[0017] The "n-decane conversion rate" is the proportion of the total amount of n-decane reacted in the hydrocracking reaction, and can be calculated by the following formula.

[0018] n-Decane Conversion Rate [%] = ([n-decane] in) - ([n-decane] out) / ([n-decane] in) × 100 (1) [n-decane] in is the concentration of n-decane at the inlet of the atmospheric pressure fixed-bed flow-type reactor, and [n-decane] out is the concentration of n-decane at the outlet of the atmospheric pressure fixed-bed flow-type reactor.

[0019] "Iso-decane" refers to isomerized n-decane.

[0020] "Iso-decane selectivity" is the proportion of iso-decane in the product, and can be calculated by the following formula:

[0021] iso-decane selectivity [C %]=(amount of iso-decane produced) / (total amount of products)×100 (2) The "cracking selectivity" is the ratio of the total amount of produced hydrocarbons with 1 to 9 carbon atoms to the total amount of products, and can be calculated using the following formula.

[0022] Cracking selectivity [C %] = (C1 + C2 + ... + C9) / (total amount of products) × 100 (3) The "cracking yield" is the ratio of the total amount of hydrocarbons with 1 to 9 carbon atoms produced to the total amount of n-decane reacted in the hydrocracking reaction, and can be calculated using the following formula.

[0023] Cracking yield [C%] = n-decane conversion × cracking selectivity / 100 (4) The "C3 / C7 ratio" refers to the ratio of the amount (mol) of hydrocarbons with three carbon atoms (hereinafter also referred to as "C3") to the amount (mol) of hydrocarbons with seven carbon atoms (hereinafter also referred to as "C7"). In the hydrocracking reaction of decane, for example, if the reaction is completely controlled by primary cracking, C3 and C7 are produced in equal molar numbers, and the C3 / C7 ratio is 1. On the other hand, if overcracking occurs, the C7 produced in the primary cracking is cleaved, resulting in C3 and hydrocarbons with four carbon atoms (hereinafter also referred to as "C4"), and the C3 / C7 ratio is greater than 1. The "C3 / C7 ratio" can be used as an evaluation index for the number of cracking reactions occurring. In other words, a C3 / C7 ratio of 1 indicates that one hydrocracking reaction of decane has occurred, while a C3 / C7 ratio greater than 1 indicates that more than one hydrocracking reaction of decane has occurred.

[0024] The amorphous silica-alumina of this embodiment will be described below.

[0025] The amorphous silica-alumina of this embodiment has a pore volume of pores having a diameter of 0 nm or more and 2 nm or less (hereinafter also referred to as "0-2 nm pore volume") relative to the pore volume of pores having a diameter of 0 nm or more and 10 nm or less (hereinafter also referred to as "0-10 nm pore volume") (hereinafter also referred to as "micropore volume ratio") of 60% or more, and a specific surface area of ​​280 m ２ / g or more.

[0026] The micropore volume ratio can be measured using a nitrogen adsorption method. Specifically, the amorphous silica-alumina of this embodiment is measured using the nitrogen adsorption method to obtain an adsorption isotherm. In the adsorption isotherm, the nitrogen adsorption amount [cm ３ (STP) / g] (hereinafter referred to as “PV （０－０．８） ") in the range of relative pressure of 0 to 0.2 [cm ３ (STP) / g] (hereinafter referred to as “PV （０－０．２） ") can be taken as the micropore volume ratio.

[0027] PV （０－０．８） and PV （０－０．２）can be obtained by a constant volume method using a general nitrogen adsorption apparatus (for example, BELSORP-mini II, manufactured by Microtrac BEL).

[0028] Measurement temperature: -196°C Pretreatment: 350°C, vacuum drying for 2 hours The micropore volume ratio of the amorphous silica-alumina of this embodiment is 60% or more. If the micropore volume ratio is less than 60%, the C3 / C7 ratio tends to become large, making it difficult to control the hydrocracking reaction by primary cracking. The micropore volume ratio is preferably 65% ​​or more, more preferably 75% or more. The upper limit of the micropore volume ratio is 100% or less, and from the viewpoint of n-decane conversion, examples include less than 100%, 95% or less, and even 85% or less. Specific examples of combinations of the upper and lower limits of the micropore volume ratio include 60% or more and 100% or less, 60% or more and less than 100%, 65% or more and 95% or less, and 75% or more and 85% or less.

[0029] PV （０－０．２） corresponds to the amount of nitrogen adsorbed by pores with a diameter of 2 nm or less, and PV （０－０．８） is considered to correspond to the amount of adsorption by pores having a diameter of 10 nm or less (for example, JIS Z 8831-2:2010). The fact that the amorphous silica-alumina of this embodiment has a micropore volume ratio of 60% or more is considered to suggest that it has many pores having a diameter of 2 nm or less. By having a micropore volume ratio of 60% or more, the amorphous silica-alumina of this embodiment can easily disperse and support active metal elements, thereby exhibiting high catalytic activity.

[0030] The amorphous silica-alumina of this embodiment has a specific surface area of ​​280 m ２ / g or more. ２ If the specific surface area is less than 290 m / g, the cracking yield is likely to decrease. ２ / g, and 300m ２ / g, more preferably 350m ２ In this embodiment, the upper limit of the specific surface area is 800 m２ / g or less, and ２ / g, and more preferably 600m ２ / g. A specific combination of the upper and lower limits of the specific surface area is 280 m ２ / g or more 800m ２ / g or less, 290m ２ / g or more 700m ２ / g or less, 300m ２ / g or more 700m ２ / g or less, or 350m ２ / g or more 650m ２ For example, it can be exemplified as being equal to or less than 1 / g.

[0031] The amorphous silica-alumina of this embodiment has a total pore volume of 0.2 cm ３ / g or more. The total pore volume is the volume of pores per unit mass of amorphous silica-alumina. The pore volume of the amorphous silica-alumina of this embodiment is determined by the nitrogen adsorption amount V [cm] in the relative pressure range of 0 to 0.99 from the nitrogen adsorption / desorption isotherm of the amorphous silica-alumina. ３ ] and the following formula can be used to calculate the value.

[0032] Total pore volume [cm ３ / g] = V × 1.547 × 10 －３ (5) The nitrogen adsorption / desorption isotherm for determining the nitrogen adsorption amount V in the above formula (5) can be obtained by the constant volume method described above.

[0033] In the amorphous silica-alumina of this embodiment, the upper limit of the pore volume is 1 cm ３ / g or less, but from the viewpoint of further increasing the cracking yield, ３ / g or less, and ３ From the viewpoint of further increasing the cracking yield, the pore volume of the amorphous silica-alumina of the present embodiment is more preferably 0.2 cm ３ / g or more 0.7cm ３ / g or less, and ３ / g or more 0.5cm ３It is more preferable that the SiO2 content is 1 / g or less.

[0034] The amorphous silica-alumina of this embodiment contains Si and Al as constituent elements. The amorphous silica-alumina of this embodiment has a molar ratio of silica to alumina (Al ２ O ３ SiO relative to converted aluminum ２ The molar ratio of silicon converted into ２ / Al ２ O ３ The ratio (SiO 2 ) is preferably 10 or more and 100 or less. Since the amorphous silica-alumina of the embodiment tends to have an acidity suitable for a cracking catalyst, the SiO 2 ２ / Al ２ O ３ The ratio is preferably 50 or less or 25 or less. In the embodiment, the amorphous silica-alumina is preferably SiO ２ / Al ２ O ３ The ratio is preferably 10 or more or 13 or more. That is, the SiO of the amorphous silica-alumina of this embodiment ２ / Al ２ O ３ The ratio may be, for example, 10 or more and 30 or less, or 13 or more and 25 or less.

[0035] The presence of Si and Al in the amorphous silica-alumina of this embodiment can be determined by performing elemental analysis by inductively coupled plasma atomic emission spectroscopy (ICP-AES) using a general high-frequency inductively coupled plasma device (for example, OPTIMA 5300DV, manufactured by PerkinElmer). Specifically, if Si and Al are detected at values ​​above the lower limit of quantification in the elemental analysis, it can be determined that the silica-alumina of this embodiment contains Si and Al. In this embodiment, SiO ２ / Al ２ O ３ The ratio is determined by the above-mentioned ICP-AES measurement from the contents of aluminum (Al) and silicon (Si) in the amorphous silica-alumina of this embodiment. ２ O ３ SiO relative to converted aluminum２ This can be calculated as the molar ratio of silicon.

[0036] The amorphous silica-alumina of this embodiment preferably has an acid amount of 0.3 mmol / g or more or 0.4 mmol / g or more, and preferably 0.8 mmol / g or less, 0.6 mmol / g or less, or 0.5 mmol / g or less. The acid amount having the above value makes it easier to improve the cracking yield. Specific combinations of the upper and lower limits of the acid amount can be exemplified as 0.3 mmol / g or more and 0.8 mmol / g or less, 0.4 mmol / g or more and 0.6 mmol / g or less, or 0.4 mmol / g or more and 0.5 mmol / g or less.

[0037] The acid amount of the amorphous silica-alumina of this embodiment may be measured by a method similar to the ammonia-TPD method (for example, "Measurement of Solid Acidity by Ammonia Temperature Programmed Desorption Method," Catalysts, Vol. 42, p. 218 (2000)). A typical catalyst analyzer (for example, BELCAT II, ​​manufactured by Microtrac) can be used for measurement by the ammonia-TPD method. Specifically, 0.05 g of amorphous silica-alumina is placed in the sample tube of the apparatus, heated to 500°C and maintained for 2 hours for pretreatment, and then the temperature is lowered to 100°C, after which ammonia is saturated and adsorbed onto the amorphous silica-alumina. Subsequently, any ammonia remaining in the measurement atmosphere is removed at 100°C, and the total acid amount can be determined from the ammonia desorption peak measured during the temperature rise process up to 800°C at a heating rate of 10°C / min. Helium may be used as the atmospheric gas for measurement. The flow rate of helium gas may be 50 ml / min.

[0038] When the amorphous silica-alumina of this embodiment is used as a catalyst for hydrocracking reaction, it preferably contains one or more elements selected from the group consisting of Groups 8, 9 and 10 (hereinafter also referred to as "active metal elements"). The amorphous silica-alumina of this embodiment has a peak area intensity (hereinafter referred to as "Al") having a peak top at a chemical shift of 40 ppm to 60 ppm. ｉｖ ") and the area intensity of the peak having a peak top at a chemical shift of -10 ppm or more and 10 ppm or less (hereinafter referred to as "Al ｖｉThe area intensity (Al ｉｖ ) ratio (hereinafter referred to as "Al ｉｖ / (Al ｉｖ +Al ｖｉ From the viewpoint of easily controlling the hydrocracking reaction of long-chain paraffins to primary cracking with higher efficiency, the Al content of the amorphous silica-alumina of this embodiment is preferably 0.40 or more and less than 0.80. ｉｖ / (Al ｉｖ +Al ｖｉ ) is preferably 0.45 or more and 0.75 or less, and more preferably 0.50 or more and 0.73 or less. Here, 27Al-MAS-NMR is known as a means for analyzing the local structure around an aluminum atom in a zeolite framework structure. In an NMR spectrum measured by 27Al-MAS-NMR, it is known that, among the aluminum (Al) contained in a zeolite, tetracoordinated aluminum (hereinafter referred to as "tetracoordinated Al") is assigned to a peak having a peak top at a chemical shift of 40 ppm or more and 60 ppm or less, and hexacoordinated aluminum (hereinafter referred to as "hexacoordinated Al") is assigned to a peak having a peak top at a chemical shift of -10 ppm or more and 10 ppm or less (for example, WO 2017 / 090751). For this reason, Al ｉｖ / (Al ｉｖ +Al ｖｉ ) functions as an index showing the ratio of tetracoordinated Al to the sum of tetracoordinated Al and hexacoordinated Al contained in the zeolite. 27Al-MAS-NMR measurement of the amorphous silica-alumina of this embodiment can be performed using a general nuclear magnetic resonance spectrometer (for example, AVANCE NEO 700, manufactured by Bruker). The measurement sample can be amorphous silica-alumina that has been calcined in air at 500°C for 1 hour and then maintained in a vacuum atmosphere in the presence of a saturated ammonium chloride aqueous solution at a relative humidity of 60% for 24 hours. The following conditions can be used for the 27Al-MAS-NMR measurement. Observation nucleus: ２７Al (182.4MHz) Rotation frequency: 24kHz Pulse width: 2.1μsec Waiting time: 2sec Number of integrations: 2600 times Al ｉｖ / (Al ｉｖ +Al ｖｉ ) is a peak having a peak top at a chemical shift of −10 ppm or more and 10 ppm or less in the NMR spectrum measured by 27Al-MAS-NMR (hereinafter referred to as “P -１０～１０ｐｐｍ ") and a peak having a peak top at a chemical shift of 40 ppm or more and 60 ppm or less (hereinafter referred to as "P ４０～６０ｐｐｍ ") and P ４０～６０ｐｐｍ Area intensity (Al ｉｖ ) to P ４０～６０ｐｐｍ Area intensity (Al ｉｖ ) and P ０ｐｐｍ Area intensity (Al ｖｉ ) can be obtained by dividing by the sum of the P -１０～１０ｐｐｍ and P ４０～６０ｐｐｍ To separate P, a conventionally known waveform separation method (peak fitting) can be used. Specifically, P can be obtained from the NMR spectrum measured by 27Al-MAS-NMR (hereinafter also referred to as the "measured NMR spectrum"). -１０～１０ｐｐｍ and P ４０～６０ｐｐｍ To separate P, the least squares method using a Gaussian function as the peak function can be used. -１０～１０ｐｐｍ and P ４０～６０ｐｐｍ The separation of one P -１０～１０ｐｐｍ and two Ps ４０～６０ｐｐｍ In order to separate the P ０ and two Ps ５５ It is preferable to assume that P -１０～１０ｐｐｍ and P ４０～６０ｐｐｍ The separation of P is preferably carried out so that the NMR spectrum obtained by recombining the separated peaks (hereinafter also referred to as the "calculated NMR spectrum") has a relative error of less than 5% at any point (ppm) with respect to the actually measured NMR spectrum. -１０～１０ｐｐｍ and P ４０～６０ｐｐｍ The area intensities of-１０～１０ｐｐｍ and P ４０～６０ｐｐｍ The integrated intensity of P -１０～１０ｐｐｍ Two or more peaks may be separated as ４０～６０ｐｐｍ When two or more peaks are separated as a result of the above, the sum of the integrated intensities of the two or more separated peaks can be used as the area intensity. Furthermore, for baseline correction, a line can be drawn connecting the points at -50 ppm and 150 ppm in the measured NMR spectrum, and the line can be corrected to 0.

[0039] The active metal element is preferably one or more selected from the group consisting of platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), nickel (Ni), and cobalt (Co), more preferably one or more selected from at least either platinum or palladium, and particularly preferably platinum.

[0040] The state of the active metal element in the amorphous silica-alumina of this embodiment is not particularly limited, but may be, for example, a compound (e.g., oxide), a metal, an ion, an alloy, or two or more of these.

[0041] The content of the active metal element contained in the amorphous silica-alumina of this embodiment is not particularly limited as long as it is within a range that achieves the effects of this embodiment. From the viewpoint of obtaining a higher cracking yield, it is preferably 0.05 mass% or more, more preferably 0.20 mass% or more, and particularly preferably 0.30 mass% or more, relative to 100 mass% of the solid content of the amorphous silica-alumina. In addition, from the viewpoint of obtaining a higher cracking yield, the upper limit of the content of the active metal element is preferably 10.0 mass% or less, more preferably 5.0 mass% or less, and particularly preferably 1.0 mass% or less. The upper and lower limits of the content of the active metal element may be any combination of the above upper and lower limits, but the specific range of the content of the active metal element is preferably 0.05 mass% or more and 10.0 mass% or less, more preferably 0.20 mass% or more and 5.0 mass% or less, and particularly preferably 0.30 mass% or more and 1.0 mass% or less.

[0042] Incidentally, "containing an active metal element" means that the amorphous silica-alumina contains an active metal element, and as long as the amorphous silica-alumina contains the active metal element, it does not matter in what state or at what position the active metal element is contained. On the other hand, "supporting an active metal element" means that the amorphous silica-alumina contains the active metal element as an atom other than that constituting the amorphous silica-alumina. In other words, "supporting an active metal element" means that the active metal element is contained in the amorphous silica-alumina in a state where the active metal element is not present as an atom constituting the amorphous silica-alumina. A preferred form of "supporting an active metal element" can be a state where the active metal element is not present as an atom constituting the amorphous silica-alumina, and is contained at least on the surface or in the pores of the amorphous silica-alumina.

[0043] When used as a catalyst for hydrocracking reaction, amorphous silica-alumina containing one or more elements selected from the group consisting of Groups 8, 9, and 10 (hereinafter also referred to as "active metal elements") can be used as a paraffin reforming catalyst containing the same (hereinafter also referred to as "catalyst of the present embodiment").

[0044] The catalyst of this embodiment can be used in a hydrocracking reaction to reform C10 or higher linear paraffins through highly efficient primary cracking, and exhibits an excellent cracking yield and C3 / C7 ratio. The C10 or higher linear paraffins to be reformed may be linear paraffins having a carbon number of 10 or more, but are preferably linear paraffins having a carbon number of 10 to 100, more preferably linear paraffins having a carbon number of 10 to 30, and particularly preferably n-decane.

[0045] The method for reforming C10 or higher linear paraffins using the catalyst of this embodiment can be achieved by a method including a step of contacting the catalyst of this embodiment with a fluid containing C10 or higher linear paraffins and hydrogen (hereinafter also referred to as a "paraffin-containing fluid") (hereinafter also referred to as a "contact step"). A specific example of a method for contacting the catalyst of this embodiment with the paraffin-containing fluid is a method in which the amorphous silica-alumina of this embodiment is packed into a stationary phase flow-type reactor tube to form a catalyst packed layer, and the paraffin-containing fluid is passed through this catalyst packed layer.

[0046] The reforming of C10 or higher linear paraffins using the catalyst of this embodiment proceeds by contacting the catalyst of this embodiment with a paraffin-containing fluid, and therefore the contact conditions are not particularly limited. Preferred contact conditions include, for example, the following conditions.

[0047] From the viewpoint of obtaining a higher cracking yield, the contact temperature between the catalyst of this embodiment and the paraffin-containing fluid is preferably 200°C or higher and 350°C or lower, and more preferably 230°C or higher and 320°C or lower.

[0048] From the viewpoint of obtaining a higher cracking yield, the pressure (gauge pressure) at which the catalyst of this embodiment is brought into contact with the paraffin-containing fluid is preferably 0.05 MPa or more and 10 MPa or less, and more preferably 0.1 MPa or more and 5 MPa or less. Note that the gauge pressure is a pressure obtained by setting atmospheric pressure to 0 MPa.

[0049] From the viewpoint of obtaining a higher cracking yield, the flow rate of hydrogen in the paraffin-containing fluid brought into contact with the catalyst of this embodiment is preferably such that the ratio of the volumetric flow rate of hydrogen to the volumetric flow rate of normal paraffins is 300 or more and 1,500 or less, and more preferably 500 or more and 1,000 or less.

[0050] The weight hourly space velocity (WHSV) of the C10 or higher normal paraffins in the paraffin-containing fluid that is brought into contact with the catalyst of this embodiment is 0.5 h from the viewpoint of obtaining a higher cracking yield. －１ 10 hours or more －１ Preferably, it is 1h or less. －１ More than 3 hours－１ The WHSV is a parameter that represents the amount of C10 or higher normal paraffin supplied per unit mass of amorphous silica-alumina per hour ([g (amorphous silica-alumina)] / [g (C10 or higher normal paraffin) / h] (=[h －１ ])).

[0051] The contact time between the catalyst of this embodiment and the paraffin-containing fluid can be set appropriately depending on the amount of Cn hydrocarbons to be obtained.

[0052] The paraffin-containing fluid to be brought into contact with the catalyst of this embodiment may be a liquid, a gas, or a mixed fluid of a liquid and a gas. From the viewpoint of obtaining a higher cracking yield, the paraffin-containing fluid is preferably a gas. Furthermore, the paraffin-containing fluid may be composed only of C10 or higher normal paraffins and hydrogen, but may also contain fluids other than these.

[0053] According to the reforming method including the contacting step described above, the catalyst of this embodiment can reform C10 or higher linear paraffins through highly efficient primary cracking. An example of the hydrocarbons primarily obtained by reforming is a hydrocarbon having half the carbon number of the hydrocarbons contacted with the catalyst of this embodiment. A more specific example is C10 when at least one of a linear paraffin having 20 carbon atoms (hereinafter also referred to as a "C20 linear paraffin") and a branched paraffin having 20 carbon atoms (hereinafter also referred to as a "C20 branched paraffin") is contacted with the catalyst of this embodiment.

[0054] The catalyst of this embodiment may have any shape, but is preferably a molded body in consideration of packing into a reaction tube.

[0055] When the catalyst of the present embodiment is a molded body, it can be molded into any shape by any molding method, such as at least one selected from the group consisting of rolling granulation molding, press molding, extrusion molding, injection molding, slip casting, and sheet molding. Examples of the shape of the molded body include at least one selected from the group consisting of spherical, approximately spherical, elliptical, disk-like, cylindrical, polyhedral, irregular, and petal-like.

[0056] When the catalyst of the present embodiment is a molded body, the molded body may contain a binder. Examples of the binder include at least one selected from the group consisting of silica, alumina, kaolin, attapulgite, montmorillonite, bentonite, and sepiolite, and alumina is preferred.

[0057] The method for producing amorphous silica-alumina according to this embodiment will be described below.

[0058] The method for producing amorphous silica-alumina of this embodiment is a production method (hereinafter also referred to as "production method of this embodiment") that includes a gelling step of mixing a solution containing an alumina source, an acid source, and water (hereinafter also referred to as "solution A") and a solution containing a basic silica source and water (hereinafter also referred to as "solution B") with an aqueous sulfate solution containing an alkali metal (hereinafter also referred to as "solution C") to obtain amorphous silica-alumina gel, an ion exchange step of ion-exchanging the amorphous silica-alumina gel, and a firing step of firing the amorphous silica-alumina gel after the ion exchange step.

[0059] Solution A is a solution containing an acid source, an alumina source, and water.

[0060] The alumina source is a compound containing aluminum (Al), and examples thereof include one or more selected from the group consisting of aluminum nitrate, aluminum sulfate, and aluminum chloride, with aluminum sulfate being preferred.

[0061] The acid source may be one or more inorganic acids selected from the group consisting of sulfuric acid, hydrochloric acid, and nitric acid. In this embodiment, from the viewpoint of production, it is preferable that the acid source is sulfuric acid. Furthermore, the acid source may contain an organic acid in addition to the inorganic acid. Examples of the organic acid include one or more selected from the group consisting of acetic acid, malic acid, tartaric acid, and citric acid.

[0062] The acid source makes it easier to control the pH in the gelation step and also reduces the SiO ２ / Al ２ O ３In terms of making it easier to control the molar ratio, the ratio of the number of moles of alkali metals contained in the silica source of Solution B (hereinafter referred to as "M ２ The molar ratio of M to anion is preferably 0.5 or more and 2.0 or less, and more preferably 0.8 or more and 1.3 or less. When the alkali metal is sodium (Na) and the anion is sulfate ion, M ２ O / anion molar ratio is Na ２ In addition, when the alkali metal is sodium or potassium (K), the M ２ The O / anion molar ratio is (Na ２ O+K ２ O) / sulfate ion molar ratio.

[0063] The water may be at least one selected from the group consisting of distilled water, deionized water, and pure water. When the alumina source and the acid source contain water, such as hydrates, structural water, or solvents, they can be considered as water contained in solution A.

[0064] The content of water in solution A is such that the specific surface area and acid amount of the resulting amorphous silica-alumina can be easily improved, and the Al contained in solution A is preferably Al. ２ O ３ The molar amount of water (hereinafter referred to as "H ２ O / Al ２ O ３ It is preferable that the molar ratio (of the hydroxyl group and the hydroxyl group) is 50 or more and 500 or less.

[0065] Solution A preferably has the following molar composition:

[0066] M ２ O / anion molar ratio: 0.5 or more, or 0.8 or more, and 2.0 or less, or 1.3 or less ２ O / Al ２ O ３ Molar ratio: 50 or more, 60 or more, or 70 or more, and 500 or less, 300 or less, or 200 or less, where M represents the alkali metal contained in solution B.

[0067] The temperature of solution A is preferably 45° C. or lower, more preferably 35° C. or lower.

[0068] Solution B is a solution containing a basic silica source and water.

[0069] The basic silica source is a basic compound containing silicon (Si), and examples thereof include one or more selected from the group consisting of sodium silicate, potassium silicate, and lithium silicate. At least one of sodium silicate and potassium silicate is preferred, and sodium silicate is more preferred.

[0070] The water is the same as that in solution A, and therefore a description thereof will be omitted.

[0071] Solution B converts the Si contained in solution B into SiO ２ The molar amount of water (hereinafter referred to as "H ２ O / SiO ２ It is preferable that the molar ratio (of the hydroxyl group and the hydroxyl group) is 8 or more and 100 or less.

[0072] Solution B preferably has the following molar composition:

[0073] H ２ O / SiO ２ Molar ratio: 8 or more, 10 or more, or 15 or more, and 100 or less, 50 or less, or 30 or less. The liquid temperature of solution B is preferably 40°C or less, more preferably 35°C or less.

[0074] In addition, Al contained in solution A is ２ O ３ The molar amount of Si contained in solution B is converted to SiO ２ The ratio of the converted molar amounts (hereinafter referred to as "SiO ２ / Al ２ O ３ The raw material molar ratio (also referred to as the "raw material molar ratio") is the SiO ２ / Al ２ O ３ In terms of ease of control of the molar ratio, the molar ratio is preferably 10 or more and 100 or less, more preferably 10 or more and 30 or less, and even more preferably 13 or more and 30 or less.

[0075] Solution C is an aqueous solution of a sulfate containing an alkali metal.

[0076] The alkali metal may be one or more selected from the group consisting of potassium, sodium, and lithium, and is preferably at least one of potassium and sodium, and more preferably sodium.

[0077] The content of the alkali metal in solution C is preferably 1% by mass or more and 5% by mass or less, since this makes it easier to obtain amorphous silica-alumina with a high specific surface area.

[0078] The content of sulfuric acid in solution C is preferably 2% by mass or more and 30% by mass or less, since this makes it easier to obtain amorphous silica-alumina with a high specific surface area.

[0079] Solution C is preferably an aqueous solution of one or more selected from the group consisting of lithium sulfate, sodium sulfate and potassium sulfate, and more preferably sodium sulfate, in view of ease of industrial handling.

[0080] The temperature of the solution C is preferably 35°C or higher and 60°C or lower.

[0081] In the gelling step, solution A and solution B are simultaneously mixed with solution C to obtain an amorphous silica-alumina gel.

[0082] In the gelation step, it is preferable to maintain the pH of solution C, which is a mixture of solutions A and B, at 6.0 or more and 8.0 or less. This allows the alumina source of solution A and the basic silica source of solution B to undergo dehydration condensation, facilitating the formation of an amorphous silica-alumina gel having the micropore volume ratio and specific surface area of ​​this embodiment. It is more preferable to maintain the pH of solution C at 6.5 or more and 7.0 or less, since this facilitates the formation of the amorphous silica-alumina gel in a shorter time.

[0083] In order to make it easier to control the pH of solution C to the above value in a shorter time, it is preferable that the ratio of the flow rate [ml / min] of solution A to the flow rate [ml / min] of solution B (hereinafter also referred to as the "A:B flow rate ratio") be a value that satisfies the following formula:

[0084] A:B flow rate ratio = 279 x (H ２O / Al ２ O ３ (molar ratio) （－０．８５） (6) In the gelation step, it is preferable to mix Solution A and Solution B into Solution C while stirring Solution C. This allows Solution A and Solution B to be uniformly dispersed, which facilitates the formation of an amorphous silica-alumina gel network and makes it easier to control the micropore volume ratio of the resulting amorphous silica-alumina. The stirring power required per unit volume (hereinafter also referred to as "P / V") is 250 W / m ３ More than 450W / m ３ It is preferable that the power consumption is 300 W / m or less. ３ More than 350W / m ３ More preferably, it is:

[0085] The liquid temperature of solution C in the gelation step is preferably 35° C. or higher and 60° C. or lower. By keeping the liquid temperature within the above range, the formation of large pores in the resulting amorphous silica-alumina is suppressed, making it easier to obtain amorphous silica-alumina having the above-mentioned micropore volume ratio. The liquid temperature of solution C in the gelation step is more preferably 40° C. or higher and 50° C. or lower.

[0086] In the ion exchange step, the alkali metal contained in the amorphous silica-alumina gel obtained in the gelling step is removed by ion exchange.

[0087] The ion exchange method may be any known method that can remove the alkali metal while suppressing the detachment of aluminum contained in the amorphous silica-alumina gel, such as a method of contacting the amorphous silica-alumina gel with an aqueous solution containing ammonium ions (hereinafter referred to as "aqueous ammonium solution") (hereinafter referred to as "ammonium ion exchange method").

[0088] The ammonium ion exchange method may be carried out by either a batch method or a flow method, but the batch method is preferred in that the alkali metal contained in the amorphous silica-alumina gel can be efficiently removed.

[0089] When the ammonium ion exchange method is carried out in a batch system, the ammonium ion concentration of the ammonium aqueous solution may be appropriately adjusted by adjusting the amount of amorphous silica-alumina gel so as to be a concentration that can sufficiently remove alkali metals, and the ammonium ion concentration may be, for example, 3% by mass or more and 10% by mass or less. Furthermore, the liquid volume of the ammonium aqueous solution may be, for example, such that the mass ratio of the ammonium aqueous solution to the solid content contained in the amorphous silica-alumina gel is 2 or more and 50 or less.

[0090] When the ammonium ion exchange method is carried out in a batch system, the time for contacting the amorphous silica-alumina gel with the ammonium aqueous solution is preferably 15 minutes to 10 hours. The temperature for contacting the amorphous silica-alumina gel with the ammonium aqueous solution may be 30° C. to 100° C., preferably 50° C. to 80° C.

[0091] When the ammonium ion exchange method is carried out in a flow-through manner, the ion exchange step can be carried out under conditions such that an ammonium ion solution having an ammonium ion concentration of 3% by mass to 10% by mass is passed through the amorphous silica-alumina gel for 1 minute to 30 minutes. The amount of the ammonium aqueous solution can be such that the mass ratio of the ammonium aqueous solution to the solid content in the amorphous silica-alumina gel is 2 to 50.

[0092] The production method of this embodiment may include, prior to the ion exchange step, a washing step of removing other components contained in the amorphous silica-alumina gel obtained in the gelling step.

[0093] In the washing step, a method for removing other components contained in the amorphous silica-alumina gel includes contacting the amorphous silica-alumina gel with water, which may be one or more selected from the group consisting of distilled water, deionized water, and pure water.

[0094] In the washing step, the amorphous silica-alumina gel is preferably brought into contact with water in an amount of 5 to 100 times by mass relative to the mass of the amorphous silica-alumina gel at 30°C to 100°C.

[0095] In the calcination step, the amorphous silica-alumina gel after the ion exchange step is calcined, thereby removing ammonium ions contained in the amorphous silica-alumina gel and obtaining amorphous silica-alumina.

[0096] The firing temperature in the firing step is preferably 300°C or higher and 600°C or lower, and more preferably 400°C or higher and 550°C or lower.

[0097] The firing time in the firing step is preferably from 10 minutes to 20 hours, more preferably from 1 hour to 3 hours.

[0098] The firing step may be carried out in an air atmosphere.

[0099] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to the following examples. (Composition Analysis) A sample solution was prepared by dissolving a measurement sample in a mixed aqueous solution of hydrofluoric acid and nitric acid. The sample solution was measured by inductively coupled plasma atomic emission spectrometry (ICP-AES) using a general ICP device (device name: OPTIMA5300DV, manufactured by PerkinElmer). From the obtained measured values ​​of aluminum (Al), silicon (Si), predetermined elements, and other elements, the SiO of the measurement sample was determined. ２ / Al ２ O ３ The ratio, the mass ratio (content) of the specified element relative to the measurement sample, and the mass ratio (content) of other elements relative to the measurement sample were determined. (Pore Characteristic Analysis) A common nitrogen adsorption apparatus (apparatus name: BELSORP-mini II, manufactured by Microtrac-Bell) was used to obtain a nitrogen adsorption / desorption isotherm for the measurement sample. The nitrogen gas adsorption was performed using a constant volume method. The measurement conditions are as follows:

[0100] Sample amount: Approximately 0.02 g Pretreatment: 350°C, vacuum drying for 2 hours Measurement temperature: -196°C Relative pressure (P / P ０) Range: 0 to 0.995 From the adsorption isotherm obtained by nitrogen adsorption measurement, the adsorption amount PV in the range of relative pressure 0 to 0.8 (nitrogen adsorption range of pores with a diameter of 10 nm or less) （０－０．８） [cm ３ (STP) / g] was calculated. In addition, the adsorption amount PV in the range of relative pressure from 0 to 0.2 (the nitrogen adsorption range corresponding to pores with a diameter of 2 nm or less) （０－０．２） [cm ３ (STP) / g] was calculated. （０－０．８） Adsorption amount PV （０－０．２） The ratio was calculated and used as the micropore volume ratio of the measurement sample.

[0101] The specific surface area of ​​the measurement sample was determined by measurement in accordance with JIS Z 8830: 2013. That is, using the nitrogen adsorption method described above, the specific surface area of ​​the amorphous silica-alumina was measured by the single-point method from the adsorption isotherm obtained by the nitrogen adsorption measurement.

[0102] From the nitrogen adsorption / desorption isotherm, the nitrogen adsorption amount V [cm ３ ] was determined, and the total pore volume of the measurement sample was calculated using the obtained adsorption amount V and the above formula (5). (Acid amount analysis) The acid amount was measured by a method based on the ammonia-TPD method (see Measurement of Solid Acidity by Ammonia Temperature Programmed Desorption Method, Catalysts, vol. 42, p. 218 (2000)). Specifically, ammonia was saturated and adsorbed on the measurement sample at room temperature, and the sample was heated to 100°C to remove ammonia remaining in the measurement atmosphere. After that, the total acid amount was determined from the ammonia desorption peak measured during the temperature rise process up to 700°C at a temperature rise rate of 10°C / min. (27Al-MAS-NMR measurement) 27Al-MAS-NMR measurement was performed to determine the amount of Al ｉｖ / (Al ｉｖ +Al ｖｉ ) was determined. A common nuclear magnetic resonance spectrometer (trade name: AVANCE NEO 700, manufactured by Bruker) was used for the measurement. As a pretreatment, the sample was baked in air at 500°C for 1 hour, and then kept in a vacuum atmosphere in the presence of a saturated ammonium chloride aqueous solution at a relative humidity of 60% for 24 hours, and this was used as the measurement sample. 27Al-MAS-NMR measurement was carried out under the following conditions. Observation nuclei: ２７Al (182.4 MHz) Rotation frequency: 24 kHz Pulse width: 2.1 μsec Waiting time: 2 sec Number of accumulations: 2600 From the NMR spectrum (actually measured NMR spectrum) obtained by 27Al-MAS-NMR measurement, ４０～６０ｐｐｍ and P -１０～１０ｐｐｍ is separated into waveforms, and P ４０～６０ｐｐｍ Area intensity Al ｉｖ And, P -１０～１０ｐｐｍ Area intensity Al ｖｉ The calculated Al ｉｖ and Al ｖｉ From this, the Al of the measurement sample ｉｖ / (Al ｉｖ +Al ｖｉ ) was determined. ｉｖ and Al ｖｉ For detection and calculation of area intensity, analysis software (software name: GRAMS / AI ver. 8.0, manufactured by Thermo Fisher Scientific) was used. ４０～６０ｐｐｍ and P -１０～１０ｐｐｍ Waveform separation was performed using the least squares method with a Gaussian function as a function representing the peak. Baseline correction was performed by connecting the points at -50 ppm and 150 ppm in the measured NMR spectrum with a straight line, and correcting the result to 0. (Pt Particle Diameter) Pt-containing amorphous silica-alumina was pressure-molded into a disk shape with a diameter of 4 cm at 500 KPa, and the resulting molded body was crushed and passed through a sieve with a mesh size of 500 μm. The granules deposited on a sieve with a mesh size of 850 μm were recovered. The resulting granules were treated in the order of steps 1 to 6 shown in the table below to prepare a measurement sample.

[0103]

[0104] The Pt particle size of the Pt-containing amorphous silica-alumina was measured by a method conforming to the carbon monoxide pulse method (Journal of the Chemical Society of Japan, No. 12, p. 218 (1989)). Specifically, using a general measuring device (product name: BEL-METAL-3SP, manufactured by Microtrac-Bell), carbon monoxide was repeatedly injected at 50°C under a helium gas flow until the amount of carbon monoxide discharged became constant. The amount of carbon monoxide adsorption was measured from the difference between the total amount of carbon monoxide introduced and the total amount of carbon monoxide discharged.

[0105] The Pt surface area was calculated from the carbon monoxide adsorption amount using the following formula.

[0106] Pt surface area [m ２ / g]=K×6.02×10 ２３ × (0.08 × 10 －１８ ) (7) (where K refers to the number of moles of CO adsorption per 1 g of the measurement sample [mol / g].) K can be calculated using the following formula.

[0107] K [mol / g] = CO adsorption amount [cm ３ (STP) / g] / (22.4×10 －３ x10 ６ ) (8) The Pt particle diameter was calculated using the following formula.

[0108] Pt particle diameter [nm] = 60 x metal content [mass%] / (Pt surface area [m ２ / g] × 21.45 (9) Example 1 Aluminum sulfate aqueous solution (Al ２ O ３ 0.366 kg of HCl (containing 8.05% by mass of Al converted from HCl), 0.14 kg of pure water, and 0.015 kg of 97% by mass sulfuric acid (manufactured by Kishida Chemical Co., Ltd.) were mixed to obtain 0.52 kg of solution A of this example. ２ O / Al ２ O ３ The molar ratio was 21.

[0109] Sodium silicate aqueous solution (SiO ２ 14.5 mass% converted to Si, Na ２0.88 kg of Na (containing 4.5% by mass of Na converted to O) and 1.07 kg of pure water were mixed to obtain 1.94 kg of solution B of this example. ２ O / SiO ２ The molar ratio was 75.

[0110] The molar composition relationship between solutions A and B was as follows:

[0111] Na ２ O / sulfate ion molar ratio: 1.3 SiO ２ / Al ２ O ３ Molar ratio of raw materials: 14.5 A 4 L heated stirring vessel was charged with 1 L of pure water, and while heating and stirring at 45°C and 346 rpm, 250 g of sodium sulfate (Kishida Chemical, anhydrous) was added, and solution A was added dropwise at a flow rate of 26 mL / min, and solution B was added dropwise at a flow rate of 103±10 mL / min so that the pH of the solution in the stirring vessel was 6.5 to 7.0, to obtain solution C of this example.

[0112] Solution C of this example was subjected to solid-liquid separation to obtain approximately 0.3 kg of amorphous silica-alumina gel. The amorphous silica-alumina gel was then washed with 3 kg of pure water, then subjected to ion exchange treatment with a 20% by mass aqueous solution of ammonium chloride, and then washed with 3 kg of pure water.

[0113] The washed amorphous silica-alumina gel was dried in an air atmosphere at 150°C for 12 hours, and then calcined in an air atmosphere at 550°C for 1 hour to obtain the amorphous silica-alumina of this example. The evaluation results of the obtained amorphous silica-alumina are shown in the table below.

[0114] Example 2: In a 3 L beaker, an aqueous solution of aluminum sulfate (Al ２ O ３ 0.240 kg of ammonium hydroxide (containing 8.05% by mass as ammonium hydroxide), 0.23 kg of pure water, and 0.064 kg of 97% by mass sulfuric acid (manufactured by Kishida Chemical Co., Ltd.) were added to obtain 0.54 kg of solution A of this example. ２ O / Al ２ O ３ The molar ratio was 21.

[0115] Sodium silicate aqueous solution (SiO ２14.5 mass% converted to Si, Na ２ 0.93 kg of Na (containing 4.5% by mass of Na converted to O) and 1.14 kg of pure water were mixed to obtain 2.07 kg of solution B of this example. ２ O / SiO ２ The molar ratio was 117.

[0116] The molar composition relationship between solutions A and B was as follows:

[0117] Na ２ O / sulfate ion molar ratio: 1.1 SiO ２ / Al ２ O ３ Molar ratio of raw materials: 23.5 Solution C of this example was obtained in the same manner as in Example 1, except that solutions A and B of this example were used.

[0118] Solution C of this example was subjected to solid-liquid separation to obtain approximately 0.3 kg (absolute dry mass) of amorphous silica-alumina gel. Subsequently, this amorphous silica-alumina gel was washed, ion-exchanged, washed, dried, and calcined in the same manner as in Example 1 to obtain amorphous silica-alumina of this example. The evaluation results of the obtained amorphous silica-alumina are shown in the table below.

[0119] Comparative Example 1 Amorphous silica-alumina of this comparative example was obtained in the same manner as in Example 1, except that solution C was obtained without adding sodium sulfate. The evaluation results of the obtained amorphous silica-alumina are shown in the table below.

[0120] Comparative Example 2 A commercially available silica-alumina catalyst carrier (manufactured by Sigma-Aldrich, Grade 135) was calcined in an air atmosphere at 550°C for 1 hour to obtain amorphous silica-alumina for this comparative example. The evaluation results of the obtained amorphous silica-alumina are shown in the table below.

[0121]

[0122]

[0123] As can be seen from the specific surface area and total pore volume of Example 1 and Comparative Example 2 shown in Table 2, the manufacturing method of this embodiment was able to obtain amorphous silica-alumina with a higher specific surface area and acid amount. Furthermore, as shown in Table 3, it was found that the obtained amorphous silica-alumina contained specific tetracoordinated Al and hexacoordinated Al.

[0124] Furthermore, the micropore volume ratios of Examples 1 and 2 and Comparative Example 3 were 60% or more, and it was found that the nitrogen adsorption amount under low relative pressure was greater than that of the commercially available silica-alumina of Comparative Example 1.

[0125] Measurement Example <Pt Loading> The amorphous silica-alumina of the Examples and Comparative Examples was loaded with H 2 O 4 so that the Pt content was 0.5 mass %. ２ PtCl ６ The powder was impregnated with the aqueous solution, dried at 110°C for 5 hours in an air atmosphere, and then calcined at 450°C for 4 hours in an air atmosphere to obtain a Pt-containing amorphous silica-alumina powder. The Pt content, Pt surface area, and Pt particle size of the obtained Pt-containing amorphous silica-alumina are shown in the table below.

[0126]

[0127] As can be seen from the Pt particle diameters of Examples 1 and 2 and Comparative Example 1 shown in Table 2, it is presumed that the increased number of pores with diameters of 2 nm or less results in smaller particle diameters of Pt particles on the support and a more highly dispersed state. On the other hand, the amorphous silica-alumina of Comparative Example 1 has many pores with diameters exceeding 2 nm. It is presumed that the Pt particles present in such large pores are less spatially restricted and grow into relatively large Pt particles. <Hydrogenolysis of n-decane> 1.1 g of the Pt-containing amorphous silica-alumina of each Example and Comparative Example was packed into a fixed-bed flow-type reactor using a stainless steel reaction tube (inner diameter 8 mm, length 650 mm), and hydrogen (gas) was passed through the reaction tube at a flow rate of 50 mL / min, a temperature of 350°C, and 0.2 MPa (gauge pressure) for 3 hours, which served as pretreatment. After the pretreatment, hydrogen (gas) was supplied to the reaction tube at a volumetric flow rate of 20 mL / min and n-decane (liquid) at a volumetric flow rate of 0.025 mL / min so that the ratio of the volumetric flow rate of hydrogen to the volumetric flow rate of n-decane was 800. The reaction mixture was heated at 280°C, 0.2 MPa (gauge pressure), and a space velocity of n-decane of 1.0 hr. －１ The hydrogenolysis reaction of n-decane was carried out so that the density of n-decane was 730 kg / cm ３ It was decided.

[0128] Ten hours after the start of n-decane flow, the outlet gas of the fixed-bed flow reactor was sampled using an autosampler (product name: trade name GHS-343A, manufactured by J-Science Co., Ltd.), and the components in the outlet gas were analyzed using gas chromatography (product name: GC-7100, manufactured by J-Science Co., Ltd.). During this time, the temperature between the outlet of the fixed-bed flow reactor and the autosampler was maintained at 220°C. A capillary column (product name: Supelco (registered trademark) SPB-Octy, manufactured by Sigma-Aldrich) was used as the gas chromatography separation column.

[0129] The n-decane conversion, iso-decane selectivity, cracking selectivity (selectivity for cracked products having 1 to 9 carbon atoms), cracking yield, and C3 / C7 ratio (molar ratio of hydrocarbons having 3 to 7 carbon atoms) are shown in the table below.

[0130]

[0131] The hydrocracking reaction of n-decane is a sequential reaction in which straight-chain hydrocarbons are reformed into shorter-carbon-chain hydrocarbons via branched hydrocarbons. If the support is weakly acidic, a relatively large amount of isomerized products (iso-decane) is produced, resulting in a low decane conversion. Conversely, if the support is too acidic, the cracking reaction proceeds, but overcracking occurs, resulting in the production of large amounts of C3 and C4, and a high C3 / C7 ratio. On the other hand, if the hydrocracking reaction of long-chain paraffins can be controlled to complete primary cracking, overcracking is suppressed, and the molar ratio of C3 to C7 is theoretically 1.

[0132] From the results in Table 5, it can be seen that the catalyst using the amorphous silica-alumina of the example as a carrier has a higher cracking yield in the hydrogenation reaction of n-decane compared to the comparative example. In addition, it can be seen that the catalyst using the amorphous silica-alumina of the example as a carrier has a C3 / C7 ratio of about 1, and it can be seen that it was possible to control the primary cracking with high efficiency.

[0133] From the above results, it can be seen that the catalyst of this embodiment has high catalytic activity and is suitable as a paraffin reforming catalyst capable of primary cracking of 10 or more straight-chain paraffins with high efficiency. The entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2024-115357, filed on July 19, 2024, are hereby incorporated by reference as part of the disclosure of the specification of the present disclosure.

Claims

1. The ratio of the pore volume of pores with a diameter of 0 nm to 2 nm to the pore volume of pores with a diameter of 0 nm to 10 nm is 60% or more, and the specific surface area is 280 m ２ / g or more.

2. Total pore volume is 0.2 cm ３ The amorphous silica-alumina according to claim 1, wherein the SiO 2 content is 1 / g or more.

3. Amorphous silica-alumina according to claim 1 or 2, wherein the molar ratio of silica to alumina is 10 or more and 100 or less.

4. Amorphous silica-alumina according to any one of claims 1 to 3, having an acid amount of 0.3 mmol / g or more.

5. The amorphous silica-alumina according to any one of claims 1 to 4, wherein the ratio of the area intensity of the peak that has a chemical shift of 40 ppm or more and 60 ppm or less to the sum of the area intensity of the peak that has a chemical shift of -10 ppm or more and 10 ppm or less, to the area intensity of the peak that has a chemical shift of 40 ppm or more and 60 ppm or less is 0.40 or more and less than 0.

80.

6. The amorphous silica-alumina according to any one of claims 1 to 5, which contains one or more elements selected from the group consisting of Groups 8, 9 and 10.

7. A method for producing amorphous silica-alumina according to any one of claims 1 to 6, comprising a gelling step of mixing a solution containing an alumina source, an acid source, and water, and a solution containing a basic silica source and water, with an aqueous sulfate solution containing an alkali metal, to obtain an amorphous silica-alumina gel; an ion exchange step of ion-exchanging the amorphous silica-alumina gel; and a firing step of firing the amorphous silica-alumina gel after the ion exchange step.

8. The method according to claim 7, wherein the aqueous sulfate solution containing an alkali metal is an aqueous solution of one or more selected from the group consisting of lithium sulfate, sodium sulfate and potassium sulfate.

9. A catalyst for reforming paraffins, comprising the amorphous silica-alumina according to any one of claims 1 to 6.

10. A method for reforming paraffins, comprising the step of contacting a paraffin-containing hydrocarbon fluid with the paraffin reforming catalyst according to claim 9.

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