Zeolite for adsorbing basic nitrogen-containing compound and adsorbent containing the same

Abstract

To provide a zeolite exhibiting a high adsorption capacity for basic nitrogen-containing compounds.SOLUTION: The present invention provides a zeolite for adsorbing basic nitrogen-containing compounds, the zeolite having the following constitutions (1) to (6). (1) The zeolite has a pore structure classified as mesoporous or macroporous. (2) The zeolite has a silica-to-alumina ratio of 100 or less. (3) The content of alkali metal in the zeolite is equal to or lower than 5 mass%. (4) The amount of solid acid measured by ammonia temperature-programmed desorption (100°C to 700°C) is equal to or higher than 0.20 mmol / g. (5) The amount of solid acid measured by ammonia temperature-programmed desorption (300°C to 700°C) is equal to or higher than 0.06 mmol / g. (6) The ratio of the solid acid amount (300°C to 700°C) to the solid acid amount (100°C to 700°C) is equal to or higher than 0.10.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a zeolite for adsorbing a basic nitrogen-containing compound and an adsorbent containing the same.

Background Art

[0002] Zeolite is a general term for crystalline porous aluminosilicates and crystalline metallosilicates. Substances having a structure similar to that of zeolite are called zeolite analogs. Zeolite and zeolite analogs (hereinafter, zeolite and zeolite analogs are collectively referred to as zeolite) have special pores derived from their skeletons, and are used in various applications by utilizing these pores. For example, by utilizing the adsorption of a compound into the pores, it is widely used in applications such as a dehydrating agent, a deodorant, and impurity removal. It is also used as an adsorbent for removing basic nitrogen-containing compounds contained in hydrocarbons.

[0003] For example, Patent Document 1 discloses that when basic nitrogen is present in a light olefin refinery stream, a zeolite oligomerization catalyst can be poisoned. Further, Patent Document 2 discloses, as a method for removing anilines, which are one of the basic nitrogen-containing compounds contained in catalytic cracking gasoline, a peak (1450 ± 10 cm -1 ) due to Lewis acid sites measured by pyridine adsorption Fourier transform infrared spectroscopy. A method of using a solid acid having a ratio (IB / IL) of the area IB of a peak (1540 ± 10 cm -1 ) due to Bronsted acid sites to the area IL of 1.0 or more as an adsorbent is disclosed. Thus, in a process in which a catalyst can be poisoned by a basic nitrogen-containing compound, an adsorbent for efficiently removing the basic nitrogen-containing compound has been demanded. Further, reduction of basic nitrogen-containing compounds has been demanded also from the viewpoint of environmental load.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a zeolite having a large adsorption amount of basic nitrogen compounds.

Means for Solving the Problems

[0006] The present inventors focused on zeolite as a substance that adsorbs basic nitrogen compounds, and by adjusting the pore diameter, SiO2 / Al2O3 ratio (silica-alumina ratio), alkali metal content, and solid acid properties of zeolite within an appropriate range, it was found that the adsorption amount of basic nitrogen compounds increases, and the present invention was completed.

[0007] Specifically, when using a zeolite having the following configurations (1) to (6), the adsorption amount of basic nitrogen compounds increases. (1) It has a pore structure classified into mesopores or macropores. (2) Silica-alumina ratio ≤ 100. (3) Alkali metal content ≤ 5% by mass. (4) Solid acid amount (100°C to 700°C) measured by ammonia temperature-programmed desorption method ≥ 0.20 mmol / g. (5) Solid acid amount (300°C to 700°C) measured by ammonia temperature-programmed desorption method ≥ 0.06 mmol / g. (6) Solid acid amount (300°C to 700°C) / solid acid amount (100°C to 700°C) ≥ 0.10.

Effects of the Invention

[0008] An object of the present invention is to provide a zeolite having a large adsorption amount of basic nitrogen compounds.

Modes for Carrying Out the Invention

[0009] The present invention includes an invention related to a zeolite for removing basic nitrogen compounds (hereinafter, also referred to as "the zeolite of the present invention"). Hereinafter, the zeolite of the present invention will be described in detail. In the present invention, when a numerical range is indicated by "~", the numerical range includes the upper and lower limit values. For example, when it is described as "1~2", it means "1 or more and 2 or less".

[0010] [Zeolite of the Present Invention] The zeolite of the present invention is a zeolite for adsorbing basic nitrogen compounds and has the following configurations (1) to (6). (1) It has a pore structure classified as mesopores or macropores. (2) Cage ratio ≤ 100. (3) Alkali metal content ≤ 5% by mass. (4) Solid acid amount (100°C to 700°C) measured by ammonia temperature-programmed desorption method ≥ 0.20 mmol / g. (5) Solid acid amount (300°C to 700°C) measured by ammonia temperature-programmed desorption method ≥ 0.06 mmol / g. (6) Solid acid amount (300°C to 700°C) / Solid acid amount (100°C to 700°C) ≥ 0.10.

[0011] The zeolite of the present invention has a pore structure classified as mesopores or macropores. The pore structure of zeolite can be classified as follows according to the number of member rings constituting the pores. The number of member rings constituting the pores can be specified from the framework type of zeolite. For example, when the framework type is FAU or BEA, the number of member rings is 12, and it has a pore structure classified as macropores. Also, for example, when the framework type is MFI, the number of member rings is 10, and it has a pore structure classified as mesopores. Furthermore, for example, when the framework type is CHA, the number of member rings is 8, and it has a pore structure classified as micropores. 8-member ring... micropores 10-member ring... mesopores 12-member ring or more... macropores When using zeolite having such a pore structure, the adsorption amount of basic nitrogen-containing compounds increases. Further, when the basic nitrogen-containing compound is aniline, it is preferably zeolite with large pores.

[0012] The silica-alumina ratio of the zeolite of the present invention is such that the silica-alumina ratio ≤ 100. The silica-alumina ratio is the molar ratio of Si and Al contained in the zeolite and is represented by SiO2 / Al2O3. The silica-alumina ratio affects the solid acidic properties, hydrophilicity, etc. of the zeolite of the present invention. The silica-alumina ratio of the zeolite of the present invention is preferably 2 ≤ silica-alumina ratio ≤ 50, and more preferably 4 ≤ silica-alumina ratio ≤ 30. The zeolite of the present invention having a silica-alumina ratio within the above range tends to have a large adsorption amount of basic nitrogen-containing compounds.

[0013] The alkali metal content of the zeolite of the present invention is such that the alkali metal content ≤ 5% by mass. The alkali metal content is represented by the mass% in terms of M2O (M = alkali metal) conversion with respect to the total mass of the zeolite of the present invention. When the zeolite of the present invention contains multiple types of alkali metals (such as Li, Na, K), M means the total thereof. The alkali metal content affects the solid acidic properties of the zeolite of the present invention. The alkali metal content of the zeolite of the present invention is preferably alkali metal content ≤ 3% by mass, and more preferably alkali metal content ≤ 1.5% by mass. The zeolite of the present invention having an alkali metal content within the above range tends to have a large adsorption amount of basic nitrogen-containing compounds.

[0014] The solid acidic property of the zeolite of the present invention is defined by the amount of solid acid measured by the ammonia temperature-programmed desorption method. This method is a method for specifying the solid acidic property by the amount of ammonia desorbed after adsorbing ammonia on the zeolite and then heating. The amount of ammonia desorbed represents the amount of solid acid, and the temperature at which ammonia desorbs represents the strength of the solid acid. In the present invention, the amount of ammonia desorbed in the range of 100°C to 700°C by the ammonia temperature-programmed desorption method is defined as the amount of solid acid (100°C to 700°C), and the amount of ammonia desorbed in the range of 300°C to 700°C is defined as the amount of solid acid (300°C to 700°C).

[0015] The solid acid amount (100°C to 700°C) of the zeolite of the present invention is such that the solid acid amount (100°C to 700°C) ≥ 0.20 mmol / g. The solid acid amount (100°C to 700°C) represents the total amount of the solid acid amount of the zeolite of the present invention. It is preferable that the solid acid amount (100°C to 700°C) of the zeolite of the present invention is such that the solid acid amount (100°C to 700°C) ≥ 0.50 mmol / g, and it is more preferable that the solid acid amount (100°C to 700°C) ≥ 1.00 mmol / g. For the zeolite of the present invention in which the solid acid amount (100°C to 700°C) is within the above range, the adsorption amount of basic nitrogen-containing compounds tends to be large. The upper limit of the solid acid amount (100°C to 700°C) of the zeolite of the present invention is not particularly limited. For example, the solid acid amount (100°C to 700°C) may be ≤ 3.00 mmol / g, or the solid acid amount (100°C to 700°C) may be ≤ 2.00 mmol / g.

[0016] The solid acid amount (300°C to 700°C) of the zeolite of the present invention is such that the solid acid amount (300°C to 700°C) ≥ 0.06 mmol / g. The solid acid amount (300°C to 700°C) represents the total amount of the solid acid with strong acid strength among the solid acid amounts of the zeolite of the present invention. It is preferable that the solid acid amount (300°C to 700°C) of the zeolite of the present invention is such that the solid acid amount (300°C to 700°C) ≥ 0.10 mmol / g, and it is more preferable that the solid acid amount (300°C to 700°C) ≥ 0.20 mmol / g. For the zeolite of the present invention in which the solid acid amount (300°C to 700°C) is within the above range, the adsorption amount of basic nitrogen-containing compounds tends to be large. The upper limit of the solid acid amount (300°C to 700°C) of the zeolite of the present invention is not particularly limited. For example, the solid acid amount (300°C to 700°C) may be ≤ 1.00 mmol / g, or the solid acid amount (300°C to 700°C) may be ≤ 0.75 mmol / g.

[0017] The ratio of the amount of solid acid of the zeolite of the present invention at 300°C to 700°C to the amount of solid acid at 100°C to 700°C (amount of solid acid (300°C to 700°C) / amount of solid acid (100°C to 700°C)) is such that amount of solid acid (300°C to 700°C) / amount of solid acid (100°C to 700°C) ≧ 0.10. This ratio represents the amount of solid acid with strong acid strength in the total amount of solid acid. The ratio of the amount of solid acid of the zeolite of the present invention at 300°C to 700°C to the amount of solid acid at 100°C to 700°C is preferably amount of solid acid (300°C to 700°C) / amount of solid acid (100°C to 700°C) ≧ 0.20, and more preferably 0.5 ≧ amount of solid acid (300°C to 700°C) / amount of solid acid (100°C to 700°C) ≧ 0.30. The zeolite of the present invention with this ratio within the aforementioned range is likely to adsorb various types of basic nitrogen-containing compounds.

[0018] The framework structure of zeolite is database-ized by the International Zeolite Association, and a framework code consisting of three capital letters is given. The framework type of the zeolite of the present invention is preferably at least one selected from FAU, MFI, and BEA. Also, when the basic nitrogen-containing compound is anilines, the framework type of the zeolite of the present invention is preferably FAU or BEA. When the framework type of the zeolite of the present invention is FAU or BEA, it is more likely to adsorb anilines.

[0019] The molar ratio of alkali metal to aluminum (M2O / Al2O3) contained in the zeolite of the present invention is preferably M2O / Al2O3 ≦ 0.50, and more preferably M2O / Al2O3 ≦ 0.10. This molar ratio affects the solid acid properties of the zeolite of the present invention. The zeolite of the present invention with this ratio within the aforementioned range is likely to have a larger adsorption amount of basic nitrogen-containing compounds.

[0020] The specific surface area of the zeolite of the present invention is preferably specific surface area ≧ 300 m 2 / g, and more preferably specific surface area ≧ 350 m 2It is more preferably / g. The zeolite of the present invention having a specific surface area within the above range is likely to have a large adsorption amount of basic nitrogen-containing compounds. The upper limit of the specific surface area of the zeolite of the present invention is not particularly limited. For example, the specific surface area ≤ 850 m 2 / g may be sufficient, and the specific surface area ≤ 800 m 2 / g may be sufficient.

[0021] The pore volume of the zeolite of the present invention represents the total pore volume calculated from the pore distribution measured by the nitrogen adsorption method. The pore volume of the zeolite of the present invention is preferably pore volume ≥ 0.20 mL / g, and more preferably pore volume ≥ 0.25 mL / g. The zeolite of the present invention having a pore volume within the above range is likely to have a large adsorption amount of basic nitrogen-containing compounds. The upper limit of the pore volume of the zeolite of the present invention is not particularly limited. For example, the pore volume ≤ 1.00 mL / g may be sufficient, and the pore volume ≤ 0.80 mL / g may be sufficient.

[0022] The zeolite of the present invention is used for removing basic nitrogen-containing compounds. For example, it can be used for removing compounds such as ammonia, amines, and anilines. It can be removed by bringing the zeolite of the present invention into contact with a fluid containing a basic nitrogen-containing compound. The fluid may be gaseous or liquid. The type of the fluid is not particularly limited either, and it may be water, olefin, etc. The zeolite of the present invention may be in powder form, or may be a molded body formed by adding a binder or the like. These can be appropriately adjusted according to the process for removing basic nitrogen-containing compounds.

[0023] The zeolite of the present invention can be synthesized, for example, by hydrothermally treating a mixture of an alumina source, a silica source, an alkali source, and water in the method described in the examples below. Also, various framework-type zeolites can be synthesized by adding a structure-directing agent if necessary.

[0024] The zeolite synthesized by the aforementioned method may have an alkali metal trapped in the ion exchange site of the zeolite. In such a case, the solid acidic property of the zeolite can be expressed by changing the ion exchange site to a proton. For example, it can be changed to a proton by suspending it in an aqueous solution containing ammonium ions, ion-exchanging the ion exchange site with ammonium ions, and then calcining and removing it. Also, by repeating this method, the alkali metal content contained in the zeolite can be reduced.

[0025] After ion-exchanging the zeolite synthesized by the aforementioned method with ammonium ions, the aluminum contained in the zeolite can be extracted by performing steam treatment. Then, by using a method for removing the aluminum extracted by acid treatment, the silica-alumina ratio and the solid acidic property of the zeolite can be adjusted.

[0026] Hereinafter, the zeolite of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0027] The methods of measurement and evaluation performed in the examples are as follows [1] to [6].

[0028] [1] Composition analysis To 0.5 g of the zeolite prepared in each example, 10 ml of HF and 1 ml of a solution prepared with H2SO4:H2O = 1:1 were added, and it was heated on a sand bath until dry. Then, 5 ml of HCl was added and dissolved, and it was diluted with pure water to 200 ml to obtain a measurement sample. Regarding the obtained measurement sample, the content of each component was measured in terms of SiO2 and Al2O3 using an inductively coupled plasma (ICP) optical emission spectrometer (manufactured by Agilent Technologies, 5800 ICP-OES), and measured in terms of Na2O using an atomic absorption spectrophotometer (manufactured by Hitachi High-Tech Corporation, ZA-3300).

[0029] [2] Identification of zeolite framework The zeolites prepared in each example were ground in a mortar to obtain a measurement sample. This measurement sample was set in an X-ray diffractometer (RINT-Ultima manufactured by Rigaku Corporation, radiation source: CuKα), scanned from 2θ = 5 to 50°, and the X-ray diffraction pattern was measured. The type of zeolite framework was identified from the obtained X-ray diffraction pattern. Specifically, the diffraction peak positions derived from various zeolite frameworks were confirmed from the technical literature (M. M. J. Treacy, J. B. Higgins, COLLECTION OF SIMULATED XRD POWDER PATTERNS FOR ZEOLITES, Fifth Revised Edition, Elsevier), and it was determined whether they matched or not. Note that since the peak position may vary slightly depending on the measurement conditions, etc., it was determined to match if it was within the range of ±0.5° from the peak position described in the above literature.

[0030] [3] Measurement of solid acid properties The zeolites prepared in each example were pretreated at 500°C for 1 hour to obtain a measurement sample. 0.05 g of this measurement sample was weighed, and the solid acid properties were evaluated by the ammonia temperature-programmed desorption method using a "BELCAT II" device manufactured by MicrotracBEL. First, He was passed through and the temperature was raised to 500°C over 1 hour, held at 500°C for 1 hour, then cooled to 100°C, and 5% ammonia / He was passed through and held at 100°C for 30 minutes. Thereafter, it was held at 100°C for 30 minutes while passing He through. While passing He through, the temperature was raised from 100°C to 700°C at a rate of 10°C / min, and the ammonia desorbed was detected with a thermal conductivity detector (TCD). After baseline correction at two points, the starting point and the ending point of desorption, the total amount of ammonia desorbed in the temperature range of 100°C to 700°C was defined as the solid acid amount (100°C to 700°C), and the total amount of ammonia desorbed in the temperature range of 300°C to 700°C was defined as the solid acid amount (300°C to 700°C).

[0031] [4] Measurement of specific surface area The zeolites prepared in each example were pretreated at 500 °C for 1 hour in an inert gas atmosphere to obtain measurement samples. This sample powder was put into a measurement sample cell, and a mixed gas with a nitrogen gas concentration of 30 vol% and a helium gas concentration of 70 vol% was allowed to flow sufficiently in a -196 °C atmosphere in a measuring device ("MR-6" manufactured by Nippon Bell Co., Ltd.) to adsorb nitrogen to the sample powder. Then, by raising the atmosphere temperature to 25 °C, the nitrogen adsorbed on the sample powder was desorbed, and the desorption amount was detected with a thermal conductivity detection method (TCD) detector. The specific surface area per 1 g of the sample powder was determined by converting the detected nitrogen desorption amount into the specific surface area using the cross-sectional area of nitrogen molecules.

[0032] [5] Pore size distribution measurement The zeolites prepared in each example were used as measurement samples, and the pore size distribution was measured by the nitrogen adsorption method under the following conditions. The total pore volume was calculated as the pore volume from the measured pore size distribution. Measurement method: Nitrogen adsorption method Measuring device: BEL SORP-miniII (manufactured by MicrotracBEL Corp.) Sample weight: Approximately 0.05 g Pretreatment: 500 °C, 1 hour (under vacuum) Relative pressure range: 0 to 1.0

[0033] [6] Aniline adsorption amount Aniline was added to heptane so that the aniline concentration became 2000 ppm to obtain an aniline-containing solution (stock solution). Next, the zeolites prepared in each example and the aniline-containing solution (stock solution) were mixed so that the zeolite weight / aniline-containing solution (stock solution) weight = 25. After stirring at room temperature for 1 hour using a stirrer, it was allowed to stand for 20 hours. Then, the zeolite was filtered off using a syringe filter, and the remaining aniline-containing solution (after removal) was recovered. Using this aniline-containing solution (after removal) as a measurement sample, the absorbance (after removal) was measured using an ultraviolet-visible near-infrared spectrophotometer (V-670) manufactured by JASCO Corporation. Also, the absorbance (before removal) of the aniline-containing solution (stock solution) was measured. Using the absorbance (before removal) and the absorbance (after removal), the aniline removal rate was calculated from the following formula. Aniline removal rate [%] = (Absorbance (before removal) - Absorbance (after removal)) / Absorbance (before removal) × 100

[0034] [Example 1: Macroporous, FAU, Cage ratio 9.6] Faujasite-type zeolite with a cage ratio of 5.0 and a Na content of 13.0 mass% in terms of Na2O (hereinafter, "NaY") was prepared. 50.0 kg of this NaY was added to 500 L of water at a temperature of 60°C, and further 14.0 kg of ammonium sulfate was added to obtain a suspension. This suspension was stirred at 70°C for 1 hour and filtered. The solid obtained by filtration was washed with water. Next, this solid was washed with an ammonium sulfate solution in which 14.0 kg of ammonium sulfate was dissolved in 500 L of water at a temperature of 60°C, and further washed with 500 L of water at 60°C, and dried at 130°C for 20 hours, so that about 65 mass% of the Na contained in NaY was ammonium ions (NH4 + )-exchanged faujasite-type zeolite (hereinafter, "NH4Y") of about 45 kg was obtained. 40 kg of this NH4Y was steam-treated at 670°C for 1 hour in a saturated steam atmosphere to obtain faujasite-type zeolite (hereinafter, "USY").

[0035] The entire amount of this USY was added to 400 L of water at a temperature of 60°C, and then 49.0 kg of ammonium sulfate was added to obtain a suspension. This suspension was stirred at 90°C for 1 hour and filtered. The cake obtained by filtration was washed with 2400 L of water at a temperature of 60°C. Next, this washed cake was dried at 130°C for 20 hours to obtain about 37 kg of faujasite-type zeolite ion-exchanged with NH4 (hereinafter, "NH4USY"). 10.0 kg of this NH4USY was steam-treated at 670°C for 2 hours in a saturated steam atmosphere to obtain about 2.7 kg of zeolite for acid treatment.

[0036] 8.0 kg of this zeolite for acid treatment was suspended in 62 L of water at room temperature, and 9.6 kg of 25 mass% sulfuric acid was gradually added to prepare an acid solution. Then, this was heated to 90°C and stirred for 1 hour. The solid obtained by filtering the acid solution after the stirring was washed with 96 L of ion-exchanged water at 60°C and further dried at 110°C for 20 hours. 200 g of the acid-treated zeolite obtained in the foregoing process was subjected to steam treatment at 350 °C for 2 hours in a saturated steam atmosphere to obtain a zeolite. The obtained zeolite was subjected to the measurements and evaluations [1] to [6] above. The results are shown in Table 1.

[0037] [Example 2: Large pores, FAU, silica-to-alumina ratio 6.9] USY was obtained in the same manner as in Example 1. The obtained USY was added to 400 L of warm water at 60 °C, adjusted to pH 2.5 to 4.5 with 25% sulfuric acid, and then 49.0 kg of ammonium sulfate was added, followed by stirring at 90 °C for 1 hour. The resulting slurry was filtered and then washed with 200 L of warm water at 60 °C to obtain a washed cake. The obtained washed cake was added to 400 L of warm water at 60 °C and stirred at 60 °C for 10 minutes. The resulting slurry was filtered and then washed with 200 L of warm water at 60 °C to obtain a washed cake. Then, the washed cake was dried at 130 °C for 20 hours to obtain a zeolite. The obtained zeolite was subjected to the measurements and evaluations [1] to [6] above. The results are shown in Table 1.

[0038] [Example 3: Large pores, FAU, silica-to-alumina ratio 75.3] A zeolite was obtained in the same manner as in Example 1, except that in the acid treatment step, the addition amount of 25% sulfuric acid was 40.0 kg and the treatment time was 4 hours. The obtained zeolite was subjected to the measurements and evaluations [1] to [6] above. The results are shown in Table 1.

[0039] [Example 4: Medium pores, MFI, silica-to-alumina ratio 23.7] To 2,425 g of pure water, 187 g of a 40% aqueous solution of tetrapropylammonium hydroxide (manufactured by Seikem Japan), 3 g of sodium hydroxide with a NaOH concentration of 98%, 97 g of an aqueous sodium aluminate solution (Al2O3 concentration: 22% by mass, Na2O concentration: 17% by mass), and 788 g of colloidal silica (HS-40 manufactured by Aldrich) were added and thoroughly mixed to obtain a raw material slurry. This raw material slurry was hydrothermally treated at 150 °C for 6 days. Thereafter, the hydrothermally treated raw material slurry was taken out, filtered, washed, and dried. The dried zeolite was added to a 50% ammonium nitrate solution so that the solid-liquid ratio became 10, and stirred at 60 °C for 1 hour. The obtained slurry was filtered, then washed with warm water at 60 °C, and dried at 120 °C. The obtained ion-exchanged dry powder was calcined to obtain zeolite. For the obtained zeolite, the measurements and evaluations [1] to [6] above were performed. The results are shown in Table 1.

[0040] [Example 5: Large pores, BEA, cage ratio 28.3] To 1,116 g of pure water, 180 g of a 35% aqueous solution of tetraethylammonium hydroxide (manufactured by Seikem Japan), 4 g of sodium hydroxide with a NaOH concentration of 98%, 131 g of an aqueous sodium aluminate solution (Al2O3 concentration: 22% by mass, Na2O concentration: 17% by mass), and 1,185 g of colloidal silica (HS-40 manufactured by Aldrich) were added and thoroughly mixed to obtain a raw material slurry. This raw material slurry was hydrothermally treated at 160 °C for 6 days. Thereafter, the hydrothermally treated raw material slurry was taken out, filtered, washed, and dried. The dried zeolite was added to a 50% ammonium nitrate solution so that the solid-liquid ratio became 10, and stirred at 60 °C for 1 hour. The obtained slurry was filtered, then washed with warm water at 60 °C, and dried at 120 °C. The obtained ion-exchanged dry powder was calcined to obtain zeolite. For the obtained zeolite, the measurements and evaluations [1] to [6] above were performed. The results are shown in Table 1.

[0041] [Comparative Example 1: Large pores, FAU, cage ratio 5.3] A faujasite-type zeolite with a silica-to-alumina ratio of 5.3 and a Na content of 12.9 mass% in terms of Na2O was used. The obtained zeolite was subjected to the measurements and evaluations of [1] to [6] above. The results are shown in Table 1.

[0042] [Comparative Example 2: Small pores, CHA, silica-to-alumina ratio 7.2] To 2,751 g of pure water, 324 g of a 25% aqueous solution of N,N,N-trimethyladamantammonium (manufactured by Seikem Japan), 3 g of potassium hydroxide with a KOH concentration of 95.5 mass%, 177 g of an aqueous sodium aluminate solution (Al2O3 concentration 22 mass%, Na2O concentration 17 mass%), and 243 g of fumed silica (Reolosil QS40 manufactured by Tokuyama) were added and thoroughly mixed to obtain a raw material slurry. This raw material slurry was hydrothermally treated at 150 °C for 96 hours. Thereafter, the hydrothermally treated raw material slurry was taken out, filtered, washed, and dried. The dried zeolite was added to a 50% ammonium nitrate solution so that the solid-liquid ratio was 10, and stirred at 60 °C for 1 hour. The obtained slurry was filtered, then washed with warm water at 60 °C, and dried at 120 °C. The obtained ion-exchanged dry powder was calcined to obtain zeolite. The obtained zeolite was subjected to the measurements and evaluations of [1] to [6] above. The results are shown in Table 1.

[0043]

Table 1

Claims

1. A zeolite for adsorbing a basic nitrogen-containing compound, comprising the following components (1) to (6). (1) It has a pore structure classified as mesopores or macropores. (2) The silica / alumina ratio ≤ 100. (3) The alkali metal content ≤ 5% by mass. (4) The amount of solid acid (100°C to 700°C) measured by the ammonia temperature-programmed desorption method ≥ 0.20 mmol / g. (5) The amount of solid acid (300°C to 700°C) measured by the ammonia temperature-programmed desorption method ≥ 0.06 mmol / g. (6) The amount of solid acid (300°C to 700°C) / the amount of solid acid (100°C to 700°C) ≥ 0.

10.

2. The zeolite according to Claim 1, comprising at least one framework type selected from FAU, MFI, and BEA.

3. The molar ratio (M 2 O / Al 2 O 3 ) of alkali metal to aluminum is such that M 2 O / Al 2 O 3 ≤ 0.50, the zeolite according to claim 2.

4. Specific surface area ≥ 300 m 2 / g, the zeolite according to claim 3.

5. The zeolite according to Claim 4, having a pore volume ≥ 0.20 mL / g.

6. A basic nitrogen-containing compound adsorbent comprising the zeolite according to any one of Claims 1 to 5.

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