Forjasite-type zeolite and method for producing the same

Abstract

To provide a faujasite-type zeolite that selectively contains Brønsted acid sites. [Solution] A faujasite-type zeolite having an SiO2 / Al2O3 molar ratio of 10 or more, containing Brønsted acid sites, and having a Lewis acid amount to Brønsted acid amount ratio of Lewis acid amount / Brønsted acid amount of 0.10 or less.

Description

[Technical Field]

[0001] The present invention relates to a faujasite-type zeolite selectively containing Brønsted acid sites and a method for producing the same. [Background technology]

[0002] Zeolites are a general term for crystalline aluminosilicates, possessing a unique pore structure and solid acid derived from their skeletal structure. Forjasite-type zeolites are crystalline aluminosilicates having a skeletal structure classified as FAU, and have been widely used as catalysts, adsorbents, and separation membranes in many industrial processes, including petroleum refining and petrochemicals. For example, catalysts containing forjasite-type zeolites, which are porous materials with strong solid acids, have long been used in industrial processes such as fluid catalytic cracking, hydrocracking, and hydrorefining, which are important processes for cracking heavy oil in petroleum to obtain high-value fractions such as gasoline (Patent Documents 1 and 2).

[0003] Among faujasite-type zeolites, faujasite-type zeolites (also called USY) from which Al has been removed from the framework by steam treatment or other methods can exhibit both Brønsted acid and Lewis acid properties. For example, Brønsted acid sites are thought to be generated by acidic hydroxyl groups present in the framework of faujasite-type zeolites. On the other hand, Lewis acid sites are thought to be generated by the removal of Al from the framework (dealuminization) due to high-temperature calcination (Non-Patent Literature 1). It is also known that such dealuminization occurs even in normal calcination treatments. Thus, among faujasite-type zeolites that can exhibit both Brønsted acid sites and Lewis acid sites, faujasite-type zeolites with an extremely low amount of Lewis acid compared to Brønsted acid, that is, faujasite-type zeolites that selectively contain Brønsted acid sites, have not been known until now. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 58-147495 [Patent Document 2] Japanese Patent Application Publication No. 3-205313 [Non-patent literature]

[0005] [Non-Patent Document 1] Yoshio Ono and Takeaki Yashima (eds.), "The Science and Engineering of Zeolites," 1st edition, Kodansha Ltd., July 10, 2000, pp. 119-134. [Overview of the project] [Problems that the invention aims to solve]

[0006] Given these circumstances, the present invention aims to provide a faujasite-type zeolite that selectively contains Brønsted acid sites. [Means for solving the problem]

[0007] The inventors first focused on a method for removing Lewis acid sites derived from extraskeletal Al produced by the dealuminization of faujasite-type zeolites. Specifically, they believed that if extraskeletal Al could be removed as much as possible while maintaining the acidic hydroxyl groups contained in the framework of the faujasite-type zeolite, a faujasite-type zeolite selectively containing Brønsted acid sites could be provided. However, conventional methods of removing extraskeletal Al by acid treatment described in Patent Document 1 or Patent Document 2 were insufficient in removing extraskeletal Al, leaving Lewis acid sites behind, making it difficult to obtain a faujasite-type zeolite selectively containing Brønsted acid sites.

[0008] The inventors conducted further studies and found that instead of the conventional method of acid treatment of faujasite-type zeolite in an open atmosphere, they performed acid treatment at a temperature exceeding 100°C in a sealed environment, followed by NH4 +A method of treating with a solution containing [it] was devised. By using this method, a faujasite-type zeolite with significantly fewer Lewis acid sites compared to the conventional method was obtained. Also, in this method, it was found that even under the harsh conditions of acid treatment at a temperature exceeding 100 °C, the framework of the faujasite-type zeolite was maintained and a drastic decrease in Bronsted acid sites could be suppressed. By using this method, it became possible to provide a faujasite-type zeolite selectively containing Bronsted acid sites.

[0009] That is, the faujasite-type zeolite of the present invention has a SiO2 / Al2O3 molar ratio of 10 or more, contains Bronsted acid sites, and the ratio of the amount of Lewis acid to the amount of Bronsted acid, expressed as the amount of Lewis acid / amount of Bronsted acid, is 0.10 or less.

[0010] Further, the method for producing the faujasite-type zeolite of the present invention includes a dealumination step of desorbing aluminum from the faujasite-type zeolite, an acid treatment step of treating the faujasite-type zeolite obtained in the dealumination step with an acid solution at a temperature exceeding 100 °C and not exceeding 200 °C, and an ammonium treatment step of treating the faujasite-type zeolite obtained in the acid treatment step with a solution containing NH4 + and is provided with.

Effects of the Invention

[0011] According to one aspect of the present invention, a faujasite-type zeolite selectively containing Bronsted acid sites can be provided.

Modes for Carrying Out the Invention

[0012] The following describes in detail the faujasite-type zeolite according to an embodiment of the present invention (hereinafter also referred to as "the zeolite according to this embodiment") and the method for producing the faujasite-type zeolite according to an embodiment of the present invention (hereinafter also referred to as "the production method according to this embodiment"). In this specification, when a numerical range is indicated by "~", that numerical range includes both an upper and lower limit. For example, "1~2" means "1 or more and 2 or less".

[0013] [Zeolite according to this embodiment] The zeolite according to this embodiment is a faujasite-type zeolite. A faujasite-type zeolite refers to a zeolite having a skeletal structure classified as "FAU" by the International Zeolite Association (IZA). In this embodiment, the presence or absence of a skeletal structure classified as FAU is determined by the X-ray diffraction method described later.

[0014] The zeolite according to this embodiment must contain Brønsted acid sites. The zeolite according to this embodiment containing Brønsted acid sites has the effect of promoting catalytic reactions in which the Brønsted acid sites act effectively. The Brønsted acid content of the zeolite according to this embodiment is preferably 10 μmol / g or more, more preferably 20 μmol / g or more, and particularly preferably 50 μmol / g or more. The Brønsted acid content may also be 1000 μmol / g or less, 750 μmol / g or less, or 500 μmol / g. The upper and lower limits of the Brønsted acid content of the zeolite according to this embodiment can be combined in any way within the above range. In this embodiment, the Brønsted acid content is calculated by the pyridine adsorption FT-IR method described later.

[0015] In this embodiment, the ratio of Lewis acid content to Brønsted acid content in the zeolite must be 0.10 or less (Lewis acid content / Brønsted acid content). The zeolite according to this embodiment, which selectively contains Brønsted acid sites, has the effect of suppressing side reactions originating from Lewis acid sites and increasing selectivity in catalytic reactions in which Brønsted acid sites are effective. In this embodiment, the ratio of Lewis acid content to Brønsted acid content is preferably 0.08 or less, and more preferably 0.06 or less. The zeolite according to this embodiment with a lower ratio can further increase selectivity in catalytic reactions in which Brønsted acid sites are effective. In this embodiment, the Lewis acid content is calculated by the pyridine adsorption FT-IR method described later, similar to the Brønsted acid content.

[0016] The SiO2 / Al2O3 molar ratio of the zeolite according to this embodiment must be 10 or higher. The higher this molar ratio, the less Al is contained in the faujasite-type zeolite, and the improved hydrothermal resistance. Therefore, the SiO2 / Al2O3 molar ratio of the zeolite according to this embodiment is preferably 15 or higher, more preferably 20 or higher, and particularly preferably 30 or higher. On the other hand, since the Al contained in the faujasite-type zeolite contributes to the formation of Brønsted acid sites, the lower this molar ratio, the greater the amount of Brønsted acid. Therefore, the SiO2 / Al2O3 molar ratio of the zeolite according to this embodiment is preferably 300 or less, more preferably 200 or less, and particularly preferably 150 or less. The upper and lower limits of the SiO2 / Al2O3 molar ratio in this embodiment can be combined in any way within the range described above.

[0017] The alkali metal content of the zeolite according to this embodiment is preferably 0.2% by mass or less in terms of M2O, where M is the alkali metal. Alkali metals can inhibit the expression of Brønsted acid sites contained in the zeolite. Therefore, the alkali metal content of the zeolite according to this embodiment is preferably 0.1% by mass or less, and more preferably 0.08% by mass or less, in terms of M2O, where M is the alkali metal. The zeolite according to this embodiment is particularly susceptible to poisoning by Na among alkali metals, so it is preferable to have a low content of Na.

[0018] The crystallinity of the zeolite according to this embodiment is preferably 1.0 or higher. In this embodiment, the crystallinity of the zeolite is an indicator of its crystallinity. Zeolites with a high crystallinity according to this embodiment tend to have high water and heat resistance. The crystallinity may also be 2.0 or lower, or 1.5 or lower. The upper and lower limits of the crystallinity of the zeolite according to this embodiment can be combined in any way within the range described above. In this embodiment, the crystallinity is calculated by X-ray diffraction measurement. Specifically, using a faujasite-type zeolite obtained by a specific method as a standard material, the intensity ratio of peaks derived from the skeletal structure of FAU obtained by X-ray diffraction measurement was calculated and this was taken as the crystallinity. A more detailed method for calculating the crystallinity is described in the examples below.

[0019] In this embodiment, the amount of Lewis acid per mole of Al in the zeolite is preferably 0.035 mol or less, more preferably 0.030 mol or less, and particularly preferably 0.025 mol or less. In this embodiment, a low amount of Lewis acid per mole of Al in the zeolite can suppress side reactions originating from Lewis acid sites.

[0020] The amount of Brønsted acid per mole of Al in the zeolite according to this embodiment is preferably 0.3 mol or more, more preferably 0.35 mol or more, and particularly preferably 0.4 mol or more. In the zeolite according to this embodiment, a higher amount of Brønsted acid per mole of Al results in higher activity in catalytic reactions where Brønsted acid sites are active sites. The amount of Brønsted acid per mole of Al in the zeolite according to this embodiment may be 1 mol or less, or 0.75 mol or less. The upper and lower limits of the amount of Brønsted acid per mole of Al in the zeolite according to this embodiment can be combined in any way within the range described above.

[0021] The specific surface area of ​​the zeolite according to this embodiment is 650 m². 2 It is preferable that the specific surface area is 850 m² or more. The zeolite according to this embodiment, which has a high specific surface area, has a well-developed pore structure derived from the skeletal structure of FAU, and exhibits high activity and selectivity in various catalytic reactions. Furthermore, the specific surface area is 850 m². 2 It may be less than / g, 820m 2 It may be less than or equal to / g. The upper and lower limits of the specific surface area of ​​the zeolite according to this embodiment can be combined in any way within the range described above.

[0022] The zeolite according to this embodiment selectively contains Brønsted acid sites and can therefore be used, for example, as one of the components of a catalyst for fluid catalytic cracking or hydrocracking in petroleum refining. In fluid catalytic cracking, using the zeolite according to this embodiment is expected to increase the amount of gasoline components. In hydrocracking, using the zeolite according to this embodiment is expected to increase the amount of high-value fractions such as kerosene produced. In petroleum refining, Brønsted acid sites act as active sites that decompose petroleum components, while Lewis acid sites can increase by-products. Therefore, catalysts that selectively contain Brønsted acid sites are needed in the field of petroleum refining, and the zeolite according to this embodiment, which selectively contains Brønsted acid sites, is very useful as one of the components that control the acidity of the catalyst.

[0023] [Manufacturing method according to this embodiment] The manufacturing method according to this embodiment includes: a dealuminization step of removing aluminum (Al) from faujasite-type zeolite; an acid treatment step of treating the faujasite-type zeolite obtained in the dealuminization step with an acid solution at a temperature of over 100°C and 200°C or less; and the faujasite-type zeolite obtained in the acid treatment step with NH4 + The method includes an ammonium treatment step in which the zeolite is treated with a solution containing [amount missing]. In the faujasite-type zeolite obtained in the dealuminization step, the detached Al exists outside the faujasite-type zeolite framework as aluminum oxide, aluminum hydroxide, and ionized aluminum oxide, etc. (the aluminum present outside the framework is collectively referred to as extra-framework Al), which causes Lewis acid sites to appear. In this manufacturing method, more extra-framework Al is removed from the faujasite-type zeolite compared to conventional manufacturing methods, and faujasite-type zeolite selectively containing Brønsted acid sites is obtained. The manufacturing method according to this embodiment will be described in detail below.

[0024] The manufacturing method according to this embodiment includes a dealuminization step for desorbing Al from the faujasite-type zeolite. The purpose of this dealuminization step is to desorb Al from the framework of the faujasite-type zeolite. The faujasite-type zeolite from which aluminum has been desorbed from the framework has a smaller lattice constant. As a method for desorbing aluminum from the faujasite-type zeolite, a method of firing the faujasite-type zeolite in air, or a method of firing the faujasite-type zeolite while steam is circulating in air can be used. In the manufacturing method according to this embodiment, it is preferable to use the method of firing the faujasite-type zeolite while steam is circulating in air. In this case, the firing temperature is preferably in the range of 500°C to 800°C, and more preferably in the range of 550°C to 750°C. The firing time is preferably in the range of 1 hour to 24 hours, and more preferably in the range of 3 hours to 12 hours.

[0025] The faujasite-type zeolite used in this aluminum removal process is preferably a faujasite-type zeolite that has been ion-exchanged with ammonium ions. Using a faujasite-type zeolite that has been ion-exchanged with ammonium ions allows for efficient removal of Al from the faujasite-type zeolite framework.

[0026] The SiO2 / Al2O3 molar ratio of the faujasite-type zeolite used in this dealuminization process is preferably in the range of 2 to 8, and more preferably in the range of 4 to 6. Faujasite-type zeolites with an SiO2 / Al2O3 molar ratio within the aforementioned range are easy to manufacture industrially. The SiO2 / Al2O3 molar ratio of the faujasite-type zeolite obtained in this dealuminization process is approximately the same as that of the faujasite-type zeolite before the dealuminization treatment, because the Al that has been removed from the framework remains on the surface. However, the lattice constant changes as Al is removed from the framework.

[0027] The lattice constant of the faujasite-type zeolite obtained in this dealuminizing process is preferably 2.427 nm or higher, and more preferably 2.430 nm or higher. Furthermore, the lattice constant is preferably 2.445 nm or lower, and more preferably 2.440 nm or lower. When the lattice constant is within this range, it is easier to obtain a faujasite-type zeolite that selectively contains Brønsted acid sites and has high hydrothermal resistance.

[0028] The manufacturing method according to this embodiment includes an acid treatment step in which the faujasite-type zeolite obtained in the aforementioned dealuminization step is treated with an acid solution at a temperature of over 100°C and 200°C or less. The purpose of this acid treatment step is to remove extraskeletal Al that exists in a lumpy form and is difficult to remove with conventional acid treatment methods. While acid treatment of faujasite-type zeolite is generally carried out at a temperature of 100°C or less, the manufacturing method according to this embodiment is carried out at a temperature of over 100°C. Since acid treatment at a temperature of over 100°C is impossible under open air, it is carried out under pressure. For example, faujasite-type zeolite can be acid treated at a temperature of over 100°C and 200°C or less using a pressurized container or autoclave. The acid treatment temperature is preferably 105°C or higher, and more preferably 110°C or higher. The acid treatment temperature may also be 180°C or lower, or 160°C or lower. The upper and lower limits of the acid treatment temperature in this acid treatment step can be combined in any way within the aforementioned range. Acid treatment at such temperatures tends to yield faujasite-type zeolites that selectively contain Brønsted acid sites. This is thought to be because acid treatment at temperatures exceeding 100°C promotes the removal of bulky extraskeletal Al. Furthermore, the fact that the faujasite-type zeolite skeleton is maintained even after acid treatment at such high temperatures was an event that would be difficult for even those skilled in the art to anticipate.

[0029] In this acid treatment process, conventionally known acids can be used as the acid. For example, sulfuric acid, nitric acid, hydrochloric acid, acetic acid, ethylenediaminetetraacetic acid, and citric acid can be used. In this process, it is preferable to use an inexpensive inorganic acid, and more preferably sulfuric acid. In this process, these acids can be dissolved in a solution and used as an acid solution, and it is preferable to use water as the solution.

[0030] In this acid treatment process, H derived from the acid + The molar amount of (H) is such that, relative to 1 mol of Al contained in the faujasite-type zeolite obtained in the aforementioned dealuminization process, +It is preferably 1.5 or more, more preferably 2 or more in terms of (H + The larger the (H + / Al), the easier it is to obtain a faujasite-type zeolite selectively containing Bronsted acid sites. Also, (H + / Al) is preferably 8 or less, more preferably 5 or less. When (H + / Al) is small, it is easy to obtain a faujasite-type zeolite with high crystallinity. The upper and lower limits of (H

[0031] In this acid treatment step, it is preferable to add a salt containing NH4 + For example, it is preferable to add ammonium sulfate, ammonium nitrate, ammonium chloride, ammonium carbonate, etc. By using an acid solution containing NH4 + in this way, in addition to bulk extra-framework Al, ionized extra-framework Al can be removed. As a result, it is easy to obtain a faujasite-type zeolite selectively containing Bronsted acid sites.

[0032] In this acid treatment step, the molar amount of NH4 + is preferably 0.5 or more, more preferably 0.75 or more in terms of (NH4 + / Al) with respect to 1 mol of Al contained in the faujasite-type zeolite obtained in the above-mentioned dealumination step. The larger the (NH4 + / Al), the easier it is to obtain a faujasite-type zeolite selectively containing Bronsted acid sites. Also, (NH4 + / Al) may be 2.0 or less, or may be 1.5 or less. The upper and lower limits of (NH4 + / Al) in this acid treatment step can be combined in any way within the above-mentioned range.

[0033] [[ID=id=33]] In this step, the acid treatment time is preferably 1 hour or more, and more preferably 2 hours or more. A longer acid treatment time makes it easier to obtain faujasite-type zeolite that selectively contains Brønsted acid sites. The lower limit of the acid treatment time is preferably 12 hours or less, and more preferably 8 hours or less. The upper and lower limits of the acid treatment time in this acid treatment step can be combined in any way within the aforementioned range.

[0034] The Na content of the faujasite-type zeolite obtained in the aforementioned dealuminization step used in this acid treatment step is preferably 15% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and particularly preferably 2% by mass or less. Using faujasite-type zeolite with a low Na content makes it easier to obtain faujasite-type zeolite that selectively contains Brønsted acid sites.

[0035] The manufacturing method according to this embodiment involves using the faujasite-type zeolite obtained in the acid treatment step as NH4 + The process includes an ammonium treatment step in which the zeolite is treated with a solution containing [a specific substance]. In the faujasite-type zeolite obtained in the aforementioned acid treatment step, the bulky extraskeletal Al may remain as oligomeric Al compounds, and these tend to remain particularly as cations at ion exchange sites. Therefore, the purpose of this ammonium treatment step is to remove the oligomeric Al compounds and the like contained in the faujasite-type zeolite obtained in the aforementioned acid treatment step.

[0036] In this ammonium treatment process, NH4 + As the solution containing the ammonium salt, a solution of ammonium salt dissolved in water can be used. For example, a solution of ammonium sulfate, ammonium nitrate, ammonium chloride, and ammonium carbonate dissolved in water can be used. The faujasite-type zeolite obtained in the aforementioned acid treatment step can be suspended in such a solution and treated with ammonium.

[0037] In this ammonium treatment process, NH4 + The molar amount of (NH4) is such that, relative to 1 mole of Al contained in the faujasite-type zeolite used as a raw material, + (NH4) is preferably 1 or more. + The larger the (NH4) value, the easier it is to obtain faujasite-type zeolites that selectively contain Brønsted acid sites. + (NH4) may be 3 or less, or 2 or less. + The upper and lower limits of / Al) can be combined in any way within the aforementioned range.

[0038] In this ammonium treatment step, the temperature of the ammonium treatment is preferably 40°C or higher, and more preferably 50°C or higher. Performing the ammonium treatment at such temperatures makes it easier to remove oligomeric Al compounds and the like. The temperature of the ammonium treatment may also be 90°C or lower, or 80°C or lower. The upper and lower limits of the temperature in this ammonium treatment step can be combined in any way within the aforementioned range.

[0039] In this ammonium treatment step, it is preferable that the ammonium treatment time is 10 minutes or more. If the ammonium treatment time is 10 minutes or more, it is easier to obtain faujasite-type zeolite that selectively contains Brønsted acid sites. The acid treatment time may be 120 minutes or less, or 90 minutes or less. The upper and lower limits of the ammonium treatment time in this ammonium treatment step can be combined in any way within the range described above.

[0040] The manufacturing method according to this embodiment may include a washing step in which the faujasite-type zeolite obtained in the ammonium treatment step described above is further washed with deionized water. Including this washing step makes it possible to remove ammonium salts remaining on the surface of the faujasite-type zeolite.

[0041] The manufacturing method according to this embodiment may include a drying step for drying the faujasite-type zeolite obtained in the ammonium treatment step described above. For example, the faujasite-type zeolite separated by filtration or the like can be dried at a temperature of 200°C or lower. Alternatively, it can be separated and dried by spray drying or the like. [Examples]

[0042] The zeolite and its manufacturing method of the present invention will be described in detail below with reference to examples, but the present invention is not limited in any way by these examples.

[0043] [Analysis method] Each of the analyses of the measurement samples obtained in the examples was performed by the following method.

[0044] (1) Measurement of the SiO2 / Al2O3 molar ratio The content (mass percentage) of each element, Si and Al, in the sample was measured using an X-ray fluorescence analyzer (Rigaku Corporation, product name "RIX-3000"). The obtained content percentages for each element were converted to SiO2 and Al2O3 content, respectively, and the SiO2 / Al2O3 molar ratio was calculated using these values.

[0045] (2) Measurement of Na content The sodium 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 the mixture was heated and evaporated to dryness to obtain a solid. Next, hydrochloric acid and water were added to this solid, and it was heated to dissolve. Then, deionized water was added to dilute it and obtain a diluted solution. The sodium concentration of this diluted solution was measured using the aforementioned atomic absorption spectrophotometer, and the sodium content was calculated by converting this to the content per gram of the sample.

[0046] (3) Identification of the skeletal structure The X-ray diffraction pattern of the sample was obtained using an X-ray diffractometer (manufactured by Rigaku Corporation, product name "SmartLab", radiation source: CuKα). The operating conditions and data processing of the X-ray diffractometer are as follows. <Driving conditions> Scan axis: 2θ / θ Source: CuKα Measurement method: Continuous method Voltage: 40kV Current: 30mA Starting angle: 2θ=14° Ending angle: 2θ = 33° Sampling width: 0.010° Scan speed: 20,000° / min

[0047] In the obtained X-ray diffraction patterns, those exhibiting peaks attributed to the diffraction planes of faujasite-type zeolites were determined to possess a faujasite structure. Specifically, the presence or absence of peaks attributed to the (331), (511), (440), (533), (642), and (555) planes in the faujasite structure was confirmed. The positions of these peaks attributed to diffraction planes can be confirmed from the technical literature (MMJTreacy, JbHiggins, COLLECTION OF SIMULATED XRD POWDERPATTERNS FOR ZEOLITES, Fifth Revised Edition, Elsevier). Note that the peak position may vary slightly depending on the measurement conditions, etc., so if it is within ±0.5° of the peak position described in the aforementioned literature, it can be considered to have a peak that belongs to the diffraction plane of faujasite-type zeolite.

[0048] (4) Calculation of crystallinity After removing the background from the X-ray diffraction pattern of the measurement sample obtained using the aforementioned X-ray diffractometer, the intensities of the peaks attributed to the (331), (511), (440), (533), (642), and (555) planes of the faujasite-type zeolite were summed and defined as I. For the faujasite-type zeolite (JRC-Z-Y5.3), a reference catalyst of the Catalysis Society of Japan, the same method was used to sum the intensities of the peaks attributed to the (331), (511), (440), (533), (642), and (555) planes of the faujasite-type zeolite, and this was defined as I0. Using I and I0, the degree of crystallinity was calculated from the following formula (A). Crystallinity (-)=I / I0...(A)

[0049] (5) Calculation of lattice constants The measurement sample and the internal standard sample (manufactured by Kanto Chemical Co., Ltd., titanium(IV) oxide (anatase type)) were mixed in a mortar in a weight ratio of 2:1 to form the measurement sample for calculating the lattice constant. Using an X-ray diffractometer (manufactured by Rigaku Corporation, product name "SmartLab"), the X-ray diffraction pattern was measured at 2θ = 23 to 28° under the same conditions as in (3) above. From the obtained X-ray diffraction pattern, the lattice constant was calculated from the following equations (1) to (3), using the 2θ that indicates the center of the peak half-width of the (533) plane and (642) plane of the TiO2 anatase type and faujasite type zeolite, respectively.

[0050]

number

[0051] A: (533) Center of peak half-width (2θ) [°] showing the plane B: (642) Center of peak half-width (2θ) [°] showing the plane C: The center of the peak half-width (2θ) [°] shown by the anatase type of TiO2.

[0052] (6) Measurement of Brønsted acid and Lewis acid levels (pyridine adsorption FT-IR method) The Brønsted acid and Lewis acid content of the sample was measured using a Fourier transform infrared spectrophotometer (manufactured by JASCO Corporation, product name "FT / IR-4600"). First, 20 mg of the sample was molded into a 20 mmΦ sample disc, which was then placed in an IR cell connected to a vacuum line and subjected to vacuum evacuation at 500°C for one hour. Next, the temperature was lowered to 150°C, and the IR spectrum was measured under the following conditions. <Condition> Measurement range: 1500cm -1 ~4000cm -1 Resolution: 4cm -1 Total number of times: 100 Detector: TGS

[0053] After measuring the aforementioned IR spectra, pyridine was introduced and allowed to adsorb sufficiently onto the sample. Next, the sample was evacuated at 250°C, cooled to 150°C, and the IR spectra of the sample disk were measured under the aforementioned conditions. Using the obtained IR spectra, the amounts of Brønsted acid and Lewis acid were calculated based on the description in the technical literature (CAEmeis, J. Catal., 141, 347~354 (1993)).

[0054] (6) Measurement of specific surface area The specific surface area of ​​the sample was measured using a product named "MR-6" manufactured by Nippon Bell Co., Ltd. The sample was packed into a sample cell and pretreated at 500°C for 1 hour under an inert gas atmosphere. Then, a nitrogen mixed gas (N2: 30 vol%, He: Balance) was sufficiently circulated at -196°C to adsorb nitrogen onto the sample. Subsequently, the temperature was raised to 25°C to desorb the adsorbed nitrogen from the sample, and the amount of desorbed nitrogen was detected using a TCD (thermal conductivity) detector. The specific surface area per gram of the sample was determined by converting the detected amount of desorbed nitrogen into specific surface area using the cross-sectional area of ​​the nitrogen molecule.

[0055] [Raw materials] The raw materials used in each experimental example and comparative example are as follows. Forjasite-type zeolite: SiO2 / Al2O3 molar ratio 5.0, Na content 13.0 mass%, lattice constant 2.466 nm, crystallinity: 1.11 Sulfuric acid aqueous solution: Sulfuric acid concentration 25% by mass Ammonium sulfate: 99.5% purity, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.

[0056] [Example 1] [Aluminum-free process] After ion exchange with ammonium ions, faujasite-type zeolite was subjected to dealuminization at 670°C for 1 hour under a steam atmosphere. Furthermore, this dealuminized faujasite-type zeolite was subjected to ion exchange with ammonium ions again, followed by dealuminization at 670°C for 2 hours under a steam atmosphere. The dealuminized faujasite-type zeolite had an SiO2 / Al2O3 molar ratio of 5.0, a Na content of 1.1 mass%, a lattice constant of 2.439 nm, and a crystallinity of 0.86.

[0057] [Acid treatment process] 15.0 g of faujasite-type zeolite obtained in the aforementioned dealuminization process was suspended in 116 mL of deionized water at room temperature to obtain a suspension. An aqueous sulfuric acid solution was gradually added to this suspension, and the ratio of the molar amount of protons derived from sulfuric acid to the molar amount of Al contained in the faujasite-type zeolite (H + The ratio (NH4) was adjusted to 2.3. Next, ammonium sulfate was added to this suspension, and the molar ratio of the amount of ammonium ions contained in the ammonium sulfate to the amount of Al contained in the faujasite-type zeolite was adjusted (NH4). + The solution was adjusted so that the ratio of (Al) was 1.0 to obtain a suspension for acid treatment. This suspension was entirely filled into a SUS pressurized container with a fluororesin inner cylinder (200 mL) and acid-treated by holding it in a 130°C dryer for 5 hours. After that, the pressurized container was cooled, the reaction product was removed from the fluororesin container, and filtered to obtain the solids.

[0058] [Ammonium treatment process] This solid content is calculated using the molar ratio (NH4) of the molar amount of ammonium ions contained in ammonium sulfate and the molar amount of Al contained in faujasite-type zeolite. + The entire volume was added to 120 mL of ammonium sulfate aqueous solution adjusted to a ratio of 1.0 (1 / Al), and treated with ammonium by holding in a suspended state at 60°C for 20 minutes. The solid obtained by filtering was washed with 180 mL of deionized water at 60°C, and then dried at 110°C for 20 hours to obtain zeolite. This zeolite was used as the measurement sample, and the aforementioned analysis was performed. The results are shown in Table 1.

[0059] [Example 2] In the acid treatment process, the ratio of the molar amount of protons derived from sulfuric acid to the molar amount of Al contained in the faujasite-type zeolite (H + Zeolite was obtained in the same manner as in Example 1, except that the ratio of (Al) was changed from 2.3 to 2.9. This zeolite was used as the measurement sample, and the aforementioned analysis was performed. The results are shown in Table 1.

[0060] [Example 3] In the acid treatment process, the ratio of the molar amount of protons derived from sulfuric acid to the molar amount of Al contained in the faujasite-type zeolite (H + Zeolite was obtained in the same manner as in Example 1, except that the ratio of (Al) was changed from 2.3 to 4.2. This zeolite was used as the measurement sample, and the aforementioned analysis was performed. The results are shown in Table 1.

[0061] [Example 4] Zeolite was obtained in the same manner as in Example 2, except that the acid treatment temperature was changed from 130°C to 110°C during the acid treatment process. This zeolite was used as the measurement sample, and the aforementioned analysis was performed. The results are shown in Table 1.

[0062] [Example 5] Zeolite was obtained in the same manner as in Example 2, except that the acid treatment temperature was changed from 130°C to 150°C during the acid treatment process. This zeolite was used as the measurement sample, and the aforementioned analysis was performed. The results are shown in Table 1.

[0063] [Comparative Example 1] 15.0 g of faujasite-type zeolite obtained in the dealuminization process of Example 1 was suspended in 116 mL of ion-exchanged water at room temperature to obtain a suspension. An aqueous sulfuric acid solution was gradually added to this suspension, and the ratio of the molar amount of protons derived from sulfuric acid to the molar amount of Al contained in the faujasite-type zeolite (H + The ratio (NH4) was adjusted to 2.0. Next, ammonium sulfate was added to this suspension, and the molar ratio of the amount of ammonium ions contained in the ammonium sulfate to the amount of Al contained in the faujasite-type zeolite was adjusted (NH4). + The solution was adjusted so that the ratio of (Al) was 1.0 to obtain a suspension for acid treatment. This suspension was treated with acid by holding it at 40°C for 5 hours. After cooling to room temperature, the reaction product was filtered to obtain the solids.

[0064] The solid was washed with 180 mL of deionized water at 60°C and then dried at 110°C for 20 hours to obtain zeolite. This zeolite was used as the sample for the analysis described above. The results are shown in Table 1.

[0065] [Comparative Example 2] The ratio of the molar amount of protons derived from sulfuric acid to the molar amount of Al contained in faujasite-type zeolite (H + Zeolite was obtained using the same method as in Comparative Example 1, except that the ratio of (Al) was changed from 2.0 to 2.6 and the acid treatment temperature was changed from 40°C to 50°C. This zeolite was used as the measurement sample, and the aforementioned analysis was performed. The results are shown in Table 1.

[0066] [Comparative Example 3] The ratio of the molar amount of protons derived from sulfuric acid to the molar amount of Al contained in faujasite-type zeolite (H + Zeolite was obtained using the same method as in Comparative Example 1, except that the ratio of (Al) was changed from 2.0 to 4.2 and the acid treatment temperature was changed from 40°C to 90°C. This zeolite was used as the measurement sample, and the aforementioned analysis was performed. The results are shown in Table 1.

[0067] [Comparative Example 4] 15.0 g of faujasite-type zeolite obtained in the dealuminization process of Example 1 was suspended in 116 mL of ion-exchanged water at room temperature to obtain a suspension. An aqueous sulfuric acid solution was gradually added to this suspension, and the ratio of the molar amount of protons derived from sulfuric acid to the molar amount of Al contained in the faujasite-type zeolite (H + The ratio (NH4 / Al) was adjusted to 4.2. Next, ammonium sulfate was added to this suspension, and the molar ratio (NH4 / Al) of the molar amount of ammonium ions contained in ammonium sulfate to the molar amount of Al contained in faujasite-type zeolite was adjusted. + The solution was adjusted so that the ratio of (Al) was 1.0 to obtain a suspension for acid treatment. This suspension was treated with acid by holding it at 90°C for 5 hours. After cooling to room temperature, the reaction product was filtered to obtain the solids.

[0068] This solid content is calculated using the molar ratio (NH4) of the molar amount of ammonium ions contained in ammonium sulfate and the molar amount of Al contained in faujasite-type zeolite. + The entire volume was added to 120 mL of ammonium sulfate aqueous solution adjusted to a ratio of 1.0 (1 / Al), and treated with ammonium by holding in a suspended state at 60°C for 20 minutes. The solid obtained by filtering was washed with 180 mL of deionized water at 60°C, and then dried at 110°C for 20 hours to obtain zeolite. This zeolite was used as the measurement sample, and the aforementioned analysis was performed. The results are shown in Table 1.

[0069] [Comparative Example 5] Zeolite was obtained using the same method as in Example 3, except that the ammonium treatment step was omitted. This zeolite was then used as a sample for the analysis described above. The results are shown in Table 1.

[0070] [Table 1]

[0071] Zeolites obtained by acid treatment at 40°C to 90°C without ammonium sulfate treatment (Comparative Examples 1-3) had a higher Lewis acid content and a higher Lewis acid content / Brønsted acid content ratio compared to the zeolites of Examples 1-5. Zeolites obtained by acid treatment at 90°C followed by ammonium sulfate treatment (Comparative Example 4), or zeolites obtained by acid treatment at 130°C without ammonium sulfate treatment (Comparative Example 5), also had a higher Lewis acid content and a higher Lewis acid content / Brønsted acid content ratio compared to the zeolites of Examples 1-5. From these results, it was confirmed that faujasite-type zeolites selectively containing Brønsted acid sites can be provided by performing acid treatment at a temperature above 100°C followed by ammonium treatment.

[0072] [Catalytic reaction evaluation] Catalytic reaction tests were conducted on the zeolites of Example 2, Example 3, Comparative Example 2, and Comparative Example 3 under the following conditions. The results are shown in Table 2.

[0073] (Catalytic reaction test) For the catalytic reaction test of the zeolite, a Micro Activity Test (MAT) apparatus manufactured by Sakuragi Rikagaku Kikai Co., Ltd., designed in accordance with ASTM-D3907-80, was used. Before conducting the catalytic reaction test, the zeolite was calcined at 500°C for 1 hour. The test conditions were as follows: Raw material: Straight-run diesel fuel (LGO) Zeolite quantity: 0.80g Oil flow amount / time: 1.60g / 90 seconds Zeolite / Oil flow rate mass ratio (C / O): 0.50 Reaction temperature: 340℃ Conversion rate = 100 - heavy distillate yield Kerosene yield = (Weight of recovered kerosene within the boiling point range) / (Weight of supplied raw material) × 100 Heavy fraction yield = (Weight of recovered heavy fraction within the boiling point range) / (Weight of supplied raw material) × 100 Boiling point range of kerosene: 145~260℃ Boiling point range of heavy distillates: 260℃+

[0074] [Table 2]

[0075] According to Table 2, the zeolite of Example 2, with a Lewis acid / Brønsted acid ratio of 0.03, showed a higher kerosene yield and equivalent conversion rate than the zeolite of Comparative Example 2, with a Lewis acid / Brønsted acid ratio of 0.19. Furthermore, the zeolite of Example 3, with a Lewis acid / Brønsted acid ratio of 0.02, showed a higher kerosene yield and equivalent conversion rate than the zeolite of Comparative Example 3, with a Lewis acid / Brønsted acid ratio of 0.14. These results confirm that by adjusting the Lewis acid / Brønsted acid ratio of the zeolite to 0.10 or less, it is possible to improve the kerosene yield while maintaining a sufficient conversion rate, thus confirming the usefulness of the zeolite of the present invention, which has a low proportion of Lewis acid.

Claims

1. SiO ２ / Al ２ O ３ The molar ratio is 10 or more. Contains Brønsted acid sites, The ratio of Lewis acid amount to Brønsted acid amount, expressed as Lewis acid amount / Brønsted acid amount, is 0.10 or less. Forjasite-type zeolite.

2. When the alkali metal content is M, ２ The faujasite-type zeolite according to claim 1, wherein the amount of oxygen is 0.2% by mass or less.

3. The faujasite-type zeolite according to claim 2, wherein the degree of crystallinity is 1.0 or higher.

4. The faujasite-type zeolite according to any one of claims 1 to 3, wherein the amount of Lewis acid per 1 mol of Al is 0.035 mol or less.

5. A dealuminizing process to remove aluminum from faujasite-type zeolite, The faujasite-type zeolite obtained in the aluminization step is treated with an acid solution at a temperature of over 100°C and 200°C or less in an acid treatment step, The faujasite-type zeolite obtained in the acid treatment step is NH ４ ＋ The process comprises an ammonium treatment step in which the patient is treated with a solution containing the following: A method for producing faujasite-type zeolite.

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