Aluminophosphate-based molecular sieve and preparation method therefor

Abstract

To provide an aluminophosphate-based molecular sieve having a new crystal shape.SOLUTION: According to the method for producing an aluminophosphate molecular sieve disclosed herein, an aluminophosphate molecular sieve having a novel crystal shape can be obtained. The method for producing the aluminophosphate molecular sieve includes a step of mixing an aluminum source, a phosphorus source, a template agent, water, and urea to prepare an aqueous gel, and a step of subjecting the aqueous gel to a hydrothermal reaction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an aluminophosphate molecular sieve. The present invention also relates to a method for producing the aluminophosphate molecular sieve. [Background technology]

[0002] Molecular sieves have uniformly sized pores, which allow them to separate substances at the molecular level, and are therefore suitable for use in adsorption, separation, and other applications. Molecular sieves are also suitable for use in catalysts. Aluminophosphate molecular sieves (ALPO molecular sieves) are known as one type of molecular sieve. ALPO molecular sieves have a framework structure in which AlO4 and PO4 tetrahedra are alternately bonded while sharing oxygen.

[0003] A hydrothermal synthesis method is known as a common method for synthesizing ALPO molecular sieves. According to the hydrothermal synthesis method, ALPO molecular sieves can be obtained as hexagonal columnar crystals (i.e., hexagonal columnar primary particles). In these hexagonal columnar crystals, multiple one-dimensional pores extend in the direction in which a pair of hexagonal bases face each other (i.e., in the direction perpendicular to the bases) (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-062228 Summary of the Invention [Problem to be solved by the invention]

[0005] The crystalline shape of ALPO molecular sieves can affect the orientation of primary particles when packed together. Therefore, the performance of ALPO molecular sieves in adsorption, separation, catalytic applications, etc. can depend on the crystalline shape of the ALPO molecular sieve. Therefore, if ALPO molecular sieves with crystalline shapes different from conventional ones could be produced, such ALPO molecular sieves would be useful in adsorption, separation, catalytic applications, etc., and the development of ALPO molecular sieves with novel crystalline shapes is desired.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an ALPO molecular sieve having a novel crystalline form. [Means for solving the problem]

[0007] The method for producing an aluminophosphate molecular sieve [1] disclosed herein includes the steps of mixing an aluminum source, a phosphorus source, a template agent, water, and urea to prepare an aqueous gel, and subjecting the aqueous gel to a hydrothermal reaction.

[0008] According to this configuration, since the aqueous gel subjected to the hydrothermal reaction contains urea, an ALPO molecular sieve having a flat crystalline shape can be obtained. This ALPO molecular sieve has a plurality of one-dimensional pores having openings on the side surfaces of the flat crystals. These primary pores are through-holes aligned in a direction parallel to the flat surfaces. Like conventional ALPO molecular sieves, this ALPO molecular sieve can adsorb molecules of a predetermined size in the through-holes. Therefore, according to this configuration, an ALPO molecular sieve having a novel crystalline shape can be provided.

[0009] The method [2] for producing an aluminophosphate molecular sieve disclosed herein is the same as the method [1], except that the amount of urea is 0.05 to 0.10 mol, calculated as Al2O3, per 1 mol of the aluminum source. With this configuration, an ALPO molecular sieve having a flat crystal shape can be effectively produced.

[0010] The method [3] for producing an aluminophosphate molecular sieve disclosed herein is the same as the method [2], except that the phosphorus source is used in an amount such that the atomic ratio of Al atoms contained in the aluminum source to P atoms contained in the phosphorus source is 10:1 to 1:10, the amount of the template agent is 0.1 to 2.0 mol per mol of the aluminum source calculated as Al2O3, and the amount of the water is 3 to 1000 mol per mol of the aluminum source calculated as Al2O3. This configuration enables the more effective production of an ALPO molecular sieve having a flat crystal shape.

[0011] The method [4] for producing an aluminophosphate molecular sieve disclosed herein is any one of the above-mentioned methods [1] to [3], in which the hydrothermal reaction is carried out in a pressure-resistant vessel at a reaction temperature of 120° C. to 250° C. According to this method, an ALPO molecular sieve having a flat crystal shape can be effectively produced.

[0012] The method [5] for producing an aluminophosphate molecular sieve disclosed herein is any one of the above-mentioned methods [1] to [4], which further comprises a step of recovering and calcining the solid content after the hydrothermal synthesis. By such a configuration, a purified ALPO molecular sieve can be obtained.

[0013] The method [6] for producing an aluminophosphate molecular sieve disclosed herein is the same as the method [5], except that the calcination temperature is 400° C. to 800° C. This method allows for more effective production of a purified ALPO molecular sieve.

[0014] From another perspective, the aluminophosphate molecular sieve [7] disclosed herein has an X-ray diffraction spectrum measured using CuKα radiation, in which the intensity ratio of the (002) plane peak to the peak with the maximum intensity appearing near 2θ=7.3° is 0.273 or less. The aluminophosphate molecular sieve having such a configuration has a novel crystal shape (in other words, the shape of the primary particles).

[0015] The aluminophosphate molecular sieve [8] disclosed herein is the same as the aluminophosphate molecular sieve [7], except that the aluminophosphate molecular sieve contains primary particles. The primary particles have a pair of flat surfaces and a side surface. The primary particles have a plurality of one-dimensional pores aligned in one direction. Each of the one-dimensional pores is a through hole having an opening in the side surface. The alignment direction of the one-dimensional pores is parallel to the flat surfaces. The aluminophosphate molecular sieve having such a configuration has a novel crystalline shape (in other words, the shape of the primary particles) as described above, and specifically has a flat crystalline shape.

[0016] In another aspect, the present invention discloses an adsorbent [9] containing the aluminophosphate-based molecular sieve [7] or [8]. In this configuration, the adsorbent can adsorb and desorb hydrocarbons (e.g., decane, etc.). [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a flowchart showing each step of the method for producing an ALPO molecular sieve according to the present invention. [Figure 2] FIG. 1 is a schematic diagram of an example of primary particles of an ALPO molecular sieve obtained by a conventional general hydrothermal synthesis method. [Figure 3] 1 is a schematic diagram of an example of a primary particle of an ALPO molecular sieve obtained by the method for producing an ALPO molecular sieve according to the present invention. FIG. [Figure 4] 1 is a scanning electron microscope image of the ALPO molecular sieve obtained in Example 1. [Figure 5] 1 is a scanning electron microscope image of the ALPO molecular sieve obtained in Example 6. [Figure 6] 1 shows XRD spectra of the ALPO molecular sieves obtained in each Example and Comparative Example 1. [Figure 7] 7 is a graph showing the relationship between the intensity ratio of the peak of the (002) plane to the peak with the maximum peak intensity (the peak near 2θ=7.3°) in the XRD spectrum of FIG. 6 and the amount of urea added. [Figure 8]1 is a graph showing the measurement results of the amount of decane desorbed from the ALPO molecular sieve obtained in Example 6. DETAILED DESCRIPTION OF THE INVENTION

[0018] Preferred embodiments of the present invention will be described below with reference to the drawings. Matters necessary for implementing the present invention other than those specifically mentioned in this specification can be understood as design matters for a person skilled in the art based on the prior art in the relevant field. The present invention can be implemented based on the contents disclosed in this specification and the common general technical knowledge in the relevant field. Furthermore, in the following drawings, components and parts that perform the same function are designated by the same reference numerals, and redundant explanations may be omitted or simplified. Dimensional relationships (length, width, thickness, etc.) in each drawing do not necessarily reflect actual dimensional relationships. Furthermore, in this specification, the notation "A to B" (A and B are arbitrary numbers) indicating a range means greater than or equal to A and less than or equal to B, and also encompasses the meanings "preferably greater than A" and "preferably smaller than B."

[0019] The essential and optional steps included in the method for producing an ALPO molecular sieve according to the present invention are shown in the flowchart of Figure 1. The method for producing an ALPO molecular sieve according to the present invention includes, as essential steps, a step S101 of mixing an aluminum source, a phosphorus source, a template agent, water, and urea to prepare an aqueous gel (hereinafter also referred to as the "gel preparation step"), and a step S102 of subjecting the aqueous gel to a hydrothermal reaction (hereinafter also referred to as the "hydrothermal reaction step"). The method for producing an ALPO molecular sieve according to the present invention may further include, as an optional step, a step S103 of recovering and calcining the solid content after the hydrothermal synthesis (hereinafter also referred to as the "calcination step"). Each step in the method for producing an ALPO molecular sieve according to the present invention will be described in detail below.

[0020] First, the gel preparation step S101 will be described. In the gel preparation step S101, at least an aluminum source, a phosphorus source, a template agent, water, and urea are used.

[0021] The aluminum source may be any known aluminum source used in the hydrothermal synthesis of ALPO molecular sieves. Examples of aluminum sources include alumina (especially alumina sol), aluminum hydroxide, boehmite, pseudoboehmite, gibbsite, aluminum trichloride, aluminum alkoxides (e.g., aluminum sec-butoxide, aluminum isopropoxide, etc.), aluminum phosphate, and sodium aluminate. These may be used alone or in combination of two or more. Among these, alumina is preferred.

[0022] The phosphorus source may be any known phosphorus source used in the hydrothermal synthesis of ALPO molecular sieves. Examples of phosphorus sources include orthophosphoric acid, ammonium hydrogen phosphate, ammonium dihydrogen phosphate, organic phosphides, aluminum phosphate, and phosphorus oxides (e.g., diphosphorus pentoxide). These may be used alone or in combination of two or more. Among these, orthophosphoric acid is preferred.

[0023] The ALPO molecular sieve usually contains Al atoms and P atoms in an atomic ratio of 1:1. Therefore, the amount of the phosphorus source is such that the atomic ratio (Al:P) of Al atoms contained in the aluminum source to P atoms contained in the phosphorus source is, for example, 10:1 to 1:10, preferably 3:1 to 1:3, more preferably 1.5:1 to 1:1.5, even more preferably 1.2:1 to 1:1.2, and most preferably 1.0:1.0.

[0024] The template agent is an additive also called a structure-directing agent (SDA). As the template agent, a known template agent used in the hydrothermal synthesis of ALPO molecular sieves can be used. Examples of the template agent include primary amines such as isopropylamine, t-butylamine, neopentylamine, and cyclohexylamine; secondary amines such as diethylamine, di-n-propylamine, diisopropylamine, n-propylmethylamine, n-propylethylamine, di-n-butylamine, di-n-pentylamine, N-methyl-n-butylamine, cyclohexylmethylamine, N-methylethanolamine, piperidine, N-methylpiperidine, and 3-methylpiperidine; tertiary amines such as triethylamine, tri-n-propylamine, triisopropylamine, diisopropylethylamine, tri-n-butylamine, dimethylbenzylamine, triethanolamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, and N-methyldiethanolamine; hydroxides of quaternary alkylammonium such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide; pyridines such as 2-methylpyridine, 3-methylpyridine, and 4-methylpyridine; morpholine; and ethylenediamine. These may be selected individually or in combination depending on the desired skeletal structure of the ALPO molecular sieve. Among these, isopropylamine, t-butylamine, di-n-propylamine, n-propylethylamine, diisopropylamine, di-n-butylamine, tri-n-propylamine, triisopropylamine, triethylamine, ethylenediamine, diisopropylethylamine, and N-methyl-n-butylamine are preferred, with triethylamine being more preferred.

[0025] The amount of the template agent may be a known amount used in the hydrothermal synthesis of an ALPO molecular sieve, and may be appropriately determined depending on the framework structure of the desired ALPO molecular sieve. The amount of the template agent is, for example, 0.1 to 2.0 mol, preferably 0.5 to 2.0 mol, per mol of the aluminum source calculated as Al2O3.

[0026] The water to be used is not particularly limited, but from the viewpoint of preventing the incorporation of impurities, it is preferable to use ion-exchanged water, ultrafiltered water, reverse osmosis water, distilled water, ultrapure water, or the like.

[0027] The amount of water is not particularly limited. From the viewpoint of ease of synthesis operation, the amount of water is, for example, 3 mol to 1000 mol, preferably 10 mol to 750 mol, more preferably 50 mol to 500 mol, and even more preferably 100 mol to 300 mol per mol of the aluminum source calculated as Al2O3 (i.e., per 2 mol of Al atoms contained in the aluminum source).

[0028] In the present invention, urea is used in the hydrothermal synthesis of ALPO molecular sieves. The use of urea allows the resulting ALPO molecular sieve to have a different crystal shape from conventional ones. Specifically, the resulting ALPO molecular sieve can have a flat crystal shape. Furthermore, the one-dimensional pores of the ALPO molecular sieve can be through-holes that have openings on the side surfaces of the crystals and are aligned in a direction parallel to the flat surfaces.

[0029] The amount of urea is not particularly limited as long as a flat crystal shape can be obtained. The amount of urea is usually 0.01 mol or more, preferably 0.03 mol or more, more preferably 0.05 mol or more, and even more preferably 0.08 mol or more, per mol of the aluminum source calculated as Al2O3. On the other hand, if the amount of urea is too much, the crystallinity of ALPO decreases, and a flat crystal shape cannot be obtained. Therefore, the amount of urea is usually 0.18 mol or less, preferably 0.15 mol or less, more preferably 0.12 mol or less, and even more preferably 0.10 mol or less, per mol of the aluminum source calculated as Al2O3. The amount of urea used is particularly preferably in the range of 0.05 mol to 0.10 mol, per mol of the aluminum source calculated as Al2O3.

[0030] In addition, as raw materials for the aqueous gel, components other than the aluminum source, phosphorus source, template agent, water, and urea may be further used in preparing the aqueous gel within a range that does not impair the effects of the present invention. In preparing the aqueous gel, only the aluminum source, phosphorus source, template agent, water, and urea may be used as raw materials for the aqueous gel.

[0031] The aluminum source, phosphorus source, template agent, water, and urea can be mixed by a known method. For example, they can be mixed by placing them in a vessel equipped with a stirring means (e.g., a stirring blade, a magnetic stirrer, etc.) and stirring. The vessel may be a pressure-resistant vessel that can be used in the next step, or may be a vessel separate from the pressure-resistant vessel.

[0032] When mixing, the aluminum source, the phosphorus source, the template agent, water, and urea may be mixed simultaneously, or two or more components may be mixed and then mixed with other components. For example, water and the aluminum source may be mixed first, and then the resulting mixture may be mixed with the phosphorus source and the template agent, and then the resulting mixture may be mixed with urea.

[0033] The temperature during mixing is not particularly limited and may be room temperature (25°C ± 10°C), or mixing may be performed under heating. The temperature during mixing is preferably 10°C to 40°C, more preferably 15°C to 25°C. The mixing time (i.e., stirring time) may be determined appropriately depending on the stirring speed. The stirring speed is preferably 100 rpm to 1500 rpm, more preferably 400 rpm to 800 rpm. The mixing time (i.e., stirring time) is preferably 0.1 hour to 24 hours, more preferably 0.5 hour to 1 hour.

[0034] An aqueous gel can be obtained by mixing an aluminum source, a phosphorus source, a template agent, water, and urea. This aqueous gel is used to perform the hydrothermal reaction step S102. The hydrothermal reaction step S102 will now be described. In the hydrothermal reaction step S102, the obtained aqueous gel is subjected to a hydrothermal reaction. Specifically, for example, the aqueous gel is heated in a pressure-resistant container to cause the hydrothermal reaction under pressure.

[0035] The pressure vessel may be any known pressure vessel used in the hydrothermal synthesis of ALPO molecular sieves, such as an autoclave, a pressure tank, or a pressure chamber.

[0036] When the gel preparation step S101 is performed using a container other than a pressure-resistant container, the aqueous gel is transferred to the pressure-resistant container. When the gel preparation step S101 is performed using a pressure-resistant container, the hydrothermal reaction step S102 can be performed while the pressure-resistant container is still being used.

[0037] The hydrothermal reaction is usually carried out under self-generated pressure. Therefore, the reaction is carried out in a sealed pressure vessel. The hydrothermal synthesis may be carried out under gas pressure to an extent that does not inhibit the crystallization of ALPO. The hydrothermal reaction may be carried out with or without stirring. The hydrothermal reaction is preferably carried out with stirring.

[0038] The heating temperature in the hydrothermal reaction step S102 is not particularly limited as long as the hydrothermal reaction occurs. The heating temperature (i.e., reaction temperature) is usually above 100°C, preferably 120°C or higher, and more preferably 150°C or higher. The heating temperature is usually 300°C or lower, preferably 250°C or lower, and more preferably 220°C or lower.

[0039] The heating time in the hydrothermal reaction step S102 is not particularly limited as long as the hydrothermal reaction occurs. The heating time is usually 1 hour or more, preferably 6 hours or more, more preferably 12 hours or more, and even more preferably 18 hours or more. The heating time is usually 120 hours or less, preferably 72 hours or less, more preferably 48 hours or less, and even more preferably 36 hours or less.

[0040] As described above, the ALPO molecular sieve can be crystallized by hydrothermal synthesis. Note that the ALPO molecular sieve produced in the hydrothermal reaction step S102 contains the template agent and urea. Therefore, it is preferable to purify the ALPO molecular sieve after the hydrothermal reaction step S102.

[0041] As a purification operation, it is preferable to further carry out a step (calcination step) S103 of recovering and calcining the solid content after the hydrothermal synthesis. Therefore, the calcination step S103 will be described.

[0042] The solid content after hydrothermal synthesis can be recovered by a known method. Examples of the method for recovering the solid content after hydrothermal synthesis include filtration, decantation, centrifugation, etc. The recovered solid content is preferably washed with water or the like and dried.

[0043] The recovered solid matter can be calcined by a known method, and residual organic components such as the template agent and urea can be removed by this calcination.

[0044] The firing temperature is not particularly limited as long as it is possible to remove the remaining organic components, and is, for example, 300° C. to 900° C., preferably 400° C. to 800° C., and more preferably 500° C. to 700° C. The firing time is not particularly limited as long as it is possible to remove the remaining organic components, and is, for example, 1 hour to 120 hours, preferably 2 hours to 24 hours, and more preferably 3 hours to 12 hours.

[0045] In this manner, a purified ALPO molecular sieve can be obtained. The method for purifying the ALPO molecular sieve is not limited to the calcination step S103, and a purification method other than calcination may be employed.

[0046] The ALPO molecular sieve obtained by the production method of the present invention has a crystal shape (i.e., primary particle shape) different from conventional ones. An example of the primary particle shape of the ALPO molecular sieve obtained by a conventional hydrothermal synthesis method is schematically shown in Figure 2.

[0047] As shown in Figure 2, a primary particle (crystal) 20 of a conventional ALPO molecular sieve has a hexagonal prism shape. Three arrows in Figure 2 represent the a-axis, b-axis, and c-axis of the hexagonal prism-shaped crystal. The primary particle 20 of the conventional ALPO molecular sieve has a pair of hexagonal base surfaces 20a and side surfaces 20b. The pair of base surfaces 20a are parallel to a plane containing the a-axis and b-axis. The side surfaces 20b are parallel to the c-axis.

[0048] The primary particle 20 of the conventional ALPO molecular sieve has a plurality of one-dimensional pores 20c extending in one direction. The plurality of one-dimensional pores 20c are aligned in one direction. For ease of reference, the size of the one-dimensional pores 20c is exaggerated in FIG. 2 . Although there are many one-dimensional pores 20c, only two are shown for simplicity. The positions and alignment of the one-dimensional pores 20c are also shown schematically. Therefore, the number, size, position, and alignment of the one-dimensional pores 20c are not limited to those shown in the illustrated example. The one-dimensional pores 20c are through-holes having openings in the pair of hexagonal bases 20a. The one-dimensional pores 20c extend in the direction in which the pair of hexagonal bases 20a face each other (i.e., perpendicular to the bases 20a). Therefore, the one-dimensional pores 20c extend along the c-axis.

[0049] In contrast, an example of a primary particle of an ALPO molecular sieve obtained by the manufacturing method of an ALPO molecular sieve according to the present invention is shown schematically in Figure 3. The three arrows in Figure 3 are oriented in the same directions as in Figure 2 and represent the a-axis, b-axis, and c-axis of the crystal. The ALPO molecular sieve 10 obtained by the manufacturing method of the present invention has a flat crystalline shape, as shown in the results of the Examples described later (particularly Figures 4 and 5).

[0050] Therefore, the primary particle 10 of the ALPO molecular sieve obtained by the production method of the present invention has a pair of flat surfaces 10a and side surfaces 10b. The pair of flat surfaces 10a are parallel to a plane including the b-axis and the c-axis. The side surfaces 10b are surfaces along the a-axis. In the illustrated example, the ALPO molecular sieve 10 has a disk shape. Therefore, the flat surfaces 10a are circular. However, the shape of the ALPO molecular sieve 10 is not limited thereto as long as it is flat. The flat surfaces 10a may be elliptical, polygonal such as rectangular, or irregular in shape. In this case, the shape and number of the side surfaces 10b may be appropriately determined according to the shape of the flat surfaces 10a.

[0051] The primary particle 10 of the ALPO molecular sieve has a plurality of one-dimensional pores 10c extending in one direction. The plurality of one-dimensional pores 10c are aligned in one direction. For ease of reference, the size of the one-dimensional pores 10c is exaggerated in FIG. 3. Although there are many one-dimensional pores 10c, only two are shown for simplicity. The position and alignment of the one-dimensional pores 10c are also shown schematically. Therefore, the number, size, position, and alignment of the one-dimensional pores 10c are not limited to those shown in the illustrated example. The one-dimensional pores 10c are through-holes with openings on the side surfaces 10b. The alignment direction of the one-dimensional pores 10c is parallel to the flat surfaces 10a. As shown in FIG. 3, the one-dimensional pores 10c extend along the c-axis.

[0052] As described above, the shape of the ALPO molecular sieve crystals (primary particles 10) obtained by the production method of the present invention is significantly different from the shape of the ALPO molecular sieve crystals (primary particles 20) obtained by the conventional hydrothermal synthesis method. The above-mentioned characteristics of the ALPO molecular sieve crystal shape obtained by the production method of the present invention can be identified by X-ray diffraction measurement using CuKα radiation.

[0053] That is, when the primary particles 10 of the ALPO molecular sieve obtained by the production method of the present invention are subjected to X-ray diffraction measurement using CuKα radiation, the ratio of the intensity of the peak of the (002) plane (peak near 2θ=21.1°) to the intensity of the peak with the maximum peak intensity (peak near 2θ=7.3°) is 0.273 or less.

[0054] From another aspect, the ALPO molecular sieve according to the present invention has an X-ray diffraction spectrum measured using CuKα radiation, in which the intensity ratio of the peak of the (002) plane to the peak with the maximum intensity appearing near 2θ=7.3° is 0.273 or less.

[0055] The ALPO molecular sieve according to the present invention comprises primary particles, which may have the following characteristics: the primary particles have a pair of flat surfaces and a side surface; the primary particles have a plurality of one-dimensional pores aligned in one direction; each one-dimensional pore is a through hole having an opening on the side surface; and the alignment direction of the one-dimensional pores is parallel to the flat surfaces.

[0056] The average major axis diameter of the primary particles of the ALPO molecular sieve may be 0.5 μm to 5.0 μm, 0.7 μm to 4.0 μm, or 0.8 μm to 3.2 μm. The primary particles of the ALPO molecular sieve may be aggregated. In this case, the average secondary particle diameter of the ALPO molecular sieve may be 1.0 μm to 10 μm, 1.5 μm to 8.0 μm, or 2.0 μm to 7.0 μm. The average major axis diameter of the primary particles and the average secondary particle diameter of the ALPO molecular sieve can be determined by obtaining a scanning electron microscope image of the ALPO molecular sieve and calculating the average major axis diameters of 10 or more arbitrarily selected primary particles and the average diameters of 10 or more arbitrarily selected secondary particles in the image.

[0057] The ratio of the major axis diameter to the minor axis diameter of the primary particles of the ALPO molecular sieve (i.e., aspect ratio) is preferably 3 or more, and more preferably 5 or more. In the present invention, the major axis diameter may be the major axis diameter of the flat plane of the primary particle, and the minor axis diameter may be the dimension of the side surface in the direction perpendicular to the flat plane. The aspect ratio of the primary particles of the ALPO molecular sieve can be determined by obtaining a scanning electron microscope image of the ALPO molecular sieve and calculating the average aspect ratio of 10 or more primary particles arbitrarily selected from the image.

[0058] ALPO molecular sieves can have various framework structures. Examples of framework structures include framework type codes defined by the International Zeolite Association (IZA): ABW, AEL, AET, AFI, AFO, AHT, ASV, ATN, ATO, ATS, ATV, AWW, BCT, BIK, BOF, CAN, CAS, CFI, CHI, CZP, DON, EEI, ESV, EUO, EWO, EZT, GON, IFO, IFR, IRN, JBW, JRY, JSW, LAU, MOR, MTF, MTT, MTW, MVY, NPO, NSI, OSI, PAR, PON, PSI, RFE, RON, RTE, RWR, SAF, SAS, SFE, SFF, SFH, SFN, SSO, SSY, STF, TON, VET, and VFI. ALPO molecular sieves may have an AFI framework structure. The skeletal structure can be analyzed by X-ray diffraction measurement, and can be controlled by appropriately selecting the type and amount of a template agent, etc.

[0059] The ALPO molecular sieve can be used in the same manner as conventional ALPO molecular sieves for adsorption, separation, catalytic applications, etc. For example, an adsorbent containing the above-mentioned ALPO molecular sieve can be prepared according to a known method. [Example]

[0060] EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0061] Example 1 Alumina (Al2O3) and H2O were added to a container equipped with a stirring blade in a molar ratio of 1:200 and mixed by stirring for 30 minutes. Next, 1 mole of orthophosphoric acid (P2O5 equivalent) and 1.55 moles of triethylamine (TEA) were added to the container for 1 mole of Al2O3 and mixed by stirring for 30 minutes. 0.05 moles of urea were then added to the container for 1 mole of Al2O3 and mixed by stirring for 10 minutes to prepare an aqueous gel.

[0062] The aqueous gel was then transferred to an autoclave and heated at 200°C for 24 hours under stirring at 40 rpm to carry out a hydrothermal reaction. The reaction product was then centrifuged, and the solid was washed with water in a funnel. The solid was then dried overnight in a dryer set at 100°C. The resulting dried product was calcined at 550°C for 10 hours to obtain ALPO molecular sieves.

[0063] Examples 2 to 6 An ALPO molecular sieve was obtained in the same manner as in Example 1, except that the amount of urea used was changed to the amount shown in Table 1.

[0064] Comparative Example 1 An ALPO molecular sieve was obtained in the same manner as in Example 1, except that urea was not added.

[0065] [Table 1]

[0066] [SEM observation evaluation] The ALPO molecular sieve powder obtained in each Example and Comparative Example 1 was pulverized in a mortar and 5 mg of the powder was placed on a carbon paste. Osmium was vapor-deposited onto the powder to prepare a sample. The shape of the primary particles of the ALPO molecular sieve was observed using a scanning electron microscope (SEM) under the following conditions: Measurement equipment: Field emission scanning electron microscope S-4800 (Hitachi High-Technologies Corporation) Detection method: SE image Accelerating voltage: 2 kV Magnification: 600x~1000x

[0067] As examples, SEM images of the ALPO molecular sieves obtained in Examples 1 and 6 are shown in FIGS. 4 and 5. In FIGS. 4 and 5, agglomerations of disk-shaped primary particles were observed in the ALPO molecular sieves. This indicates that ALPO molecular sieves having flat crystal shapes were obtained in Examples 1 and 6. Furthermore, the SEM images of Examples 2 to 5 also showed that ALPO molecular sieves having flat crystal shapes were obtained. On the other hand, hexagonal columnar crystals were obtained in Comparative Example 1.

[0068] Table 1 also shows the major axis diameters of the primary particles and secondary particle diameters of the ALPO molecular sieves obtained in Examples 1 to 6, which were measured from SEM images.

[0069] [XRD measurement evaluation] Powder X-ray diffraction (XRD) measurements were carried out under the following conditions for the ALPO molecular sieves obtained in each Example and Comparative Example 1. The obtained XRD spectra are shown in FIG. Measurement device: RINT TTR III (Rigaku Corporation) Operation axis: 2θ / θ Source: CuKα Measurement method: Continuous Voltage: 40kV Current: 250mA Starting angle: 2θ=5° End angle: 2θ=85° Sampling width: 0.02° Scan speed: 8.00° / min Divergence slit: 1° Divergence vertical limit slit: 10 mm Scattering slit: 8 mm Receiving slit: 13 mm

[0070] The XRD spectrum confirmed that an AFI-type ALPO molecular sieve was obtained. Here, urea was not added in Comparative Example 1, but the amount of urea added was increased from Example 1 to Example 6. In the XRD spectrum of FIG. 6, the peak intensity of the (002) plane (the intensity of the peak near 2θ=21.1°) decreased with increasing amount of urea added. This suggests that the addition of urea suppressed the growth of the a-axis length (see FIG. 3).

[0071] The calculated intensity ratio of the (002) plane peak to the peak with the maximum peak intensity (peak near 2θ=7.3°) is shown in Fig. 7. From the graph in Fig. 7, it can be said that the crystal shape of the ALPO molecular sieve is flat when this peak intensity ratio is 0.273 or less.

[0072] [Adsorption test] 1.0 g of the ALPO molecular sieve obtained in Example 6 was weighed out and transferred to a tablet press with a diameter of 35 mm. It was compressed for 1 minute at a pressure of 26 MPa using a hydraulic hand press (TP-40 manufactured by HERZOG) to prepare a disk-shaped sample. This disk-shaped sample was roughly crushed in a mortar, and the crushed material was passed through a sieve with a mesh size of 1 mm and then a sieve with a mesh size of 0.5 mm. This resulted in pellet samples with sizes of 0.5 mm to 1 mm.

[0073] A pellet sample with a dry weight of 0.5 g was placed in the adsorption apparatus. Pretreatment was performed by increasing the temperature to 500°C at a rate of 25°C / min to remove HCs and water remaining in the pores of the ALPO molecular sieve. Next, the adsorption apparatus was cooled to 100°C, and then 3000 ppmC decane (C 10 H 22 A mixed gas containing ALPO and 3% water was passed through the adsorption device at a flow rate of 5 L / min for 15 minutes. The gas was then switched to 100% N2 and passed through for 5 minutes. After that, the temperature was increased to 550°C at a rate of 20°C / min while N2 was still passing through. This allowed the decane adsorbed on the ALPO molecular sieve to be desorbed. The amount of decane adsorbed on the ALPO molecular sieve (mg / g) was calculated by integrating the amount of desorbed decane. The results of the decane desorption evaluation are shown in Figure 8.

[0074] As shown in Figure 8, desorption of decane was observed. This indicates that the ALPO molecular sieve of Example 6 can adsorb decane and actually functions as a molecular sieve. The amount of decane desorbed per 1 g of ALPO molecular sieve was 15.32 mg / g.

[0075] From the above results, it is clear that according to the present invention, an aluminosilicate (ALPO) with a novel crystalline form is obtained, and this ALPO has the function of a molecular sieve.

[0076] Although several embodiments of the present invention have been described above, the above embodiments are merely examples. The present invention can be implemented in various other forms. The present invention can be implemented based on the contents disclosed in this specification and the common general technical knowledge in the relevant field. The technology described in the claims includes various modifications and alterations of the above-exemplified embodiments.

Claims

1. mixing an aluminum source, a phosphorus source, a template agent, water, and urea to prepare an aqueous gel; subjecting the aqueous gel to a hydrothermal reaction; The method for producing an aluminophosphate molecular sieve includes:

2. The amount of urea is Al ２ O ３ The method according to claim 1, wherein the amount of the aluminum source is 0.05 mol to 0.10 mol per 1 mol of the aluminum source.

3. the amount of the phosphorus source used is an amount such that the atomic ratio of Al atoms contained in the aluminum source to P atoms contained in the phosphorus source is 10:1 to 1:10; The amount of the template agent is Al ２ O ３ the amount is 0.1 moles to 2.0 moles relative to 1 mole of the aluminum source calculated as a conversion amount; The amount of water is Al ２ O ３ The method according to claim 2, wherein the amount of the aluminum source is 3 mol to 1,000 mol per 1 mol of the aluminum source calculated as a conversion amount.

4. The hydrothermal reaction is carried out in a pressure-resistant vessel, and the reaction temperature of the hydrothermal reaction is 120°C or higher and 250°C or lower. The method of claim 1.

5. The method according to claim 1 , further comprising the step of recovering and calcining the solid content obtained after the hydrothermal synthesis.

6. The method according to claim 5, wherein the firing temperature is 400°C to 800°C.

7. An aluminophosphate molecular sieve, wherein in an X-ray diffraction spectrum measured using CuKα radiation, the intensity ratio of the peak of the (002) plane to the peak with the maximum intensity appearing near 2θ=7.3° is 0.273 or less.

8. the aluminophosphate molecular sieve comprises primary particles; The primary particle has a pair of flat surfaces and a side surface, the primary particles have a plurality of one-dimensional pores aligned in one direction, Each of the one-dimensional pores is a through hole having an opening on the side surface, The direction in which the one-dimensional pores are aligned is parallel to the flat surface. The aluminophosphate molecular sieve of claim 7.

9. An adsorbent comprising the aluminophosphate molecular sieve of claim 7.

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