JP5119663B2 - AFI type iron aluminophosphate and method for producing the same - Google Patents

Description

  The present invention relates to an AFI type iron aluminophosphate and a method for producing the same, and more particularly to a fine particle AFI type iron aluminophosphate useful as a catalyst or an adsorbent and a method for producing the same.

As a method for producing an AFI type iron aluminophosphate (hereinafter referred to as “FAPO-5” as appropriate), a method of hydrothermal synthesis in a stationary state using a template without stirring is generally known. ing.
JP 2004-136269 A

  On the other hand, when zeolite such as FAPO-5 is used as a catalyst or adsorbent, it is necessary to optimize its activity, diffusion state of reaction substrate, reactant or adsorbate. It is necessary to be. In general, as a method of producing fine particle FAPO-5, a method of pulverizing the produced large particles can be considered.

  By the way, in the conventional method for producing fine-particle FAPO-5, it is difficult to produce at an industrial level due to the difficulty in raising the temperature and by-product impurities due to non-uniformity of the gel. Furthermore, since only relatively large particles can be obtained, a pulverization step is necessary. Moreover, since a part of the structure is broken by the pulverization, there arises a problem that the amount of adsorption is reduced, for example. Therefore, a new means for directly synthesizing fine particles by hydrothermal synthesis is desired.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a fine particle FAPO-5 useful as a catalyst or an adsorbent and a method for producing fine particle FAPO-5 that can be produced at an industrial level. There is to do.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have conducted hydrothermal synthesis while stirring a predetermined aqueous starting material at a specific stirring linear speed, thereby allowing fine FAPO-5 to be obtained without pulverization. Was found and the present invention was completed.

  That is, the gist of the present invention resides in FAPO-5, which is fine particle FAPO-5 obtained without being mechanically pulverized and has an average particle diameter of 15 microns or less. And in the preferable aspect of such FAPO-5, the difference of the adsorption amount of relative humidity 0.14 and 0.3 in a 35 degreeC water vapor adsorption isotherm is 0.14 g / g or more.

  Another gist of the present invention is the above-described FAPO-5 production method, which is 0.05 m / s or more in hydrothermal synthesis of an aqueous starting material containing a P source, an Al source, an Fe source and a template. The production method of FAPO-5 is characterized in that stirring is performed at a stirring linear velocity of The stirring linear velocity is obtained by the following formula (1).

  Since FAPO-5 according to the present invention is a fine particle obtained without being mechanically pulverized, the structure does not break and is excellent in properties such as adsorption / desorption properties. In addition, according to the method for producing FAPO-5 according to the present invention, it is possible to industrially produce fine FAPO-5 without breaking the structure by hydrothermal synthesis while stirring the aqueous starting material at a specific stirring linear velocity. It becomes possible to manufacture at the level. Such FAPO-5 can be widely used as an industrially useful catalyst or adsorbent.

  Hereinafter, the present invention will be described in more detail. The FAPO-5 of the present invention is a fine particle FAPO-5 obtained without mechanical pulverization, and has an average particle diameter of 15 microns or less. Here, mechanical pulverization refers to pulverization using a pulverizer described in, for example, Chemical Engineering Handbook (published by Maruzen Co., Ltd., 1988, pages 826-837).

  Specific examples of the method for obtaining fine particles of FAPO-5 having an average particle size of 15 microns or less without mechanical pulverization include hydrothermal synthesis, dissolution with chemicals such as acids and alkalis, and electropolishing. It is done. Among these, the method obtained by hydrothermal synthesis is preferable because it does not require a micronization step and there is no destruction of the crystal structure due to micronization.

  In the present invention, the average particle diameter means the average when there is a major axis or a minor axis, and the particle diameter can be measured by a laser diffraction method. The average particle diameter of FAPO-5 of the fine particles according to the present invention preferably has a lower limit of 1 μm or more and an upper limit of 15 μm or less. Such an upper limit is more preferably 10 μm or less, and even more preferably 5 μm or less. The reason for prescribing the average particle size within the above range is that when the average particle size is smaller than 1 μm, the handling becomes worse, and when the average particle size is larger than 15 μm, the surface area becomes smaller and the catalytic activity becomes lower. Moreover, because a pulverization step is required, a part of the structure is broken.

  The above particle size is controlled by the stirring linear velocity during hydrothermal synthesis, the temperature control during preparation of the aqueous starting material, and the composition adjustment of the aqueous starting material. In the present invention, the aqueous starting material is a mixed raw material before hydrothermal synthesis obtained by mixing a phosphorus source (P source), an aluminum source (Al source), an iron source (Fe source) and a template. Point to.

  In the present invention, “aluminophosphate” refers to crystalline aluminosilicates and crystalline aluminophosphates according to International Zeolite Association (IZA) regulations. The structure is a code defined by IZA, which is AFI.

  The fine particle FAPO-5 according to the present invention is a crystalline iron aluminophosphate containing aluminum, phosphorus and iron in a skeleton structure, and iron is substituted with aluminum and / or phosphorus in the skeleton. The crystalline iron aluminophosphate preferably has an abundance ratio of atoms represented by the following formulas (2), (3) and (4).

  And among the above-mentioned abundance ratios of atoms, those in which the abundance ratio of iron is represented by the following formula (5) are preferable, and those represented by the following formula (6) are more preferable.

  In the present invention, elements other than Fe, Al and P may be contained in the skeleton structure of the crystalline iron aluminophosphate. Examples of other elements include silicon, lithium, magnesium, titanium, zirconium, vanadium, chromium, manganese, cobalt, nickel, palladium, copper, zinc, gallium, germanium, arsenic, tin, calcium, and boron. Usually, the molar ratio (M / Fe) between the other elements (M) and iron (Fe) is 3 or less, preferably 1.5 or less, more preferably 0.5 or less. The reason is that when M / Fe is not in this range, sufficient adsorption performance is not exhibited.

  The fine particle FAPO-5 according to the present invention preferably has a difference in adsorption amount between 0.14 g / g and 0.15 g / g or more at a relative humidity of 0.14 and 0.3 on a water vapor adsorption isotherm at 35 ° C. / G or more is more preferable. When the difference in adsorption amount is large as described above, since the amount of adsorbent can be reduced when used in an adsorption heat pump or the like, there is an advantage that the apparatus can be made compact. The relative humidity has a specific value for the sake of convenience. Regarding the characteristics of the FAPO-5, the adsorption is said to show a relatively large water vapor adsorption amount difference in this relatively narrow relative humidity range. The shape of the isotherm is important.

  FAPO-5 is generally obtained by performing temperature control during the preparation of an aqueous starting material and performing hydrothermal synthesis without stirring. Of course, it can be expected that the particle size is reduced by stirring during hydrothermal synthesis. However, with SAPO-34, the particle size does not decrease even when stirring is carried out during hydrothermal synthesis. In FAPO-5, the relationship between stirring during hydrothermal synthesis and the particle size of the generated particles is not known.

The feature of the present invention is that the fine particle FAPO-5 can be directly synthesized by performing a stirring operation under specific conditions during hydrothermal synthesis. That is, in the production method of the present invention for obtaining the above-mentioned FAPO-5, 0.05 m / s or more is required when hydrothermal synthesis is performed while stirring an aqueous starting material containing a P source, an Al source, an Fe source and a template. Stir at the line speed of stirring.

  In the present invention, stirring means that the aqueous starting material can be made uniform, the number and shape of the stirring blades as the stirring means, the distance between the stirring blades and the inner wall of the reactor, the baffle plate on the inner wall of the reactor The presence or absence of is not particularly limited. As the shape of the stirring blade, specifically, the propeller, angled flat blade, pitched flat blade, flat blade disk turbine described in Chemical Engineering Handbook (published by Maruzen Co., Ltd., 1988, pages 891-916), Examples include flat blades, curved blades, faldler types, bull margin types, helical types, helical ribbon types, anchor types, and improved anchor types.

  The stirring linear velocity is preferably 0.05 m / s or more, more preferably 0.1 m / s or more, and even more preferably 0.5 m / s or more. The upper limit of the stirring linear velocity is limited by the capacity of the motor. The reason why the lower limit of the stirring linear velocity is specified is that, when the stirring linear velocity is less than 0.05 m / s, the particle size of the resulting particles increases and the surface area decreases, so that the catalytic activity decreases, and pulverization occurs. This is because a process is required, and a part of the structure is destroyed at that time.

[Hydrothermal synthesis]
In the present invention, hydrothermal synthesis is carried out by placing an aqueous starting material in a pressure vessel and stirring at a predetermined temperature of 0.05 m / s or higher under a self-generated pressure or a pressurized gas that does not inhibit crystallization. It is done by holding. The temperature condition in the hydrothermal synthesis is usually 100 to 300 ° C., and preferably 150 to 250 ° C., more preferably 170 to 220 ° C. from the viewpoint of ease of synthesis.

  The reaction time is usually 3 hours to 30 days, and preferably 5 hours to 15 days, more preferably 6 hours to 7 days, from the viewpoint of ease of synthesis. After hydrothermal synthesis, the product is separated, washed with water, dried, and part or all of the organic matter contained is removed by a method such as firing using air to obtain the above-mentioned FAPO-5.

[Constituent materials]
The starting materials in the hydrothermal synthesis of FAPO-5 are an aluminum source (Al source), a phosphorus source (P source), an iron source (Fe source) and a template as shown below.

[Aluminum source]
Although it does not specifically limit as an Al source, Usually, aluminum alkoxides, such as pseudo boehmite, aluminum isopropoxide, and aluminum triethoxide, aluminum hydroxide, alumina sol, sodium aluminate, etc. are mentioned. Among them, pseudoboehmite is preferable in terms of excellent handleability and high reactivity.

[Phosphorus source]
As the P source, phosphoric acid is usually used, but aluminum phosphate may be used.

[Iron source]
The Fe source is not particularly limited, but is usually an organic acid such as iron sulfate, iron nitrate, iron phosphate, iron chloride, iron bromide or other inorganic acid iron, iron acetate, iron oxalate, iron citrate or the like. Examples thereof include iron organometallic compounds such as iron acid, iron pentacarbonyl, and ferrocene. Among these, inorganic acid irons and organic acid irons are preferable because they are easily dissolved in water, and inorganic acid iron compounds such as ferric nitrate and ferrous sulfate are more preferable. In some cases, colloidal iron hydroxide or the like may be used.

[Other elements]
The skeleton structure of iron aluminophosphate may contain other elements as long as the above-described adsorption / desorption characteristics are not impaired. Examples of other elements include silicon, lithium, magnesium, titanium, zirconium, vanadium, chromium, manganese, cobalt, nickel, iron, palladium, copper, zinc, gallium, germanium, arsenic, tin, calcium, and boron.

[template]
As a template, quaternary ammonium salts such as tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, morpholine, di-n-propylamine, tri-n-propylamine, tri-n-isopropylamine, triethylamine, Triethanolamine, piperidine, piperazine, cyclohexylamine, 2-methylpyridine, N, N-dimethylbenzylamine, N, N-diethylethanolamine, dicyclohexylamine, N, N-dimethylethanolamine, choline, N, N Dimethylpiperazine, 1,4-diazabicyclo (2,2,2) octane, N-methyldiethanolamine, N-methylethanolamine, N-methylpiperidine, 3-methylpiperidine, N-methyl Cyclohexylamine, 3-methylpyridine, 4-methylpyridine, quinuclidine, N, N′-dimethyl-1,4-diazabicyclo- (2,2,2) octane ion, di-n-butylamine, neopentylamine, di- primary amines such as n-pentylamine, isopropylamine, t-butylamine, ethylenediamine, pyrrolidine, 2-imidazolidone, di-isopropyl-ethylamine, dimethylcyclohexylamine, cyclopentylamine, N-methyl-n-butylamine, hexamethyleneimine, Secondary amines, tertiary amines, and polyamines may be mentioned. These may be used as a mixture. Among these, triethylamine, isopropylamine, di-n-isopropylamine, tri-n-propylamine, and tetraethylammonium hydroxide are preferable in terms of reactivity, and industrially cheaper triethylamine is more preferable. These may be used alone or in combination of two or more.

[Preparation of aqueous starting material]
The aqueous starting material is prepared by mixing the above Al source, Fe source, P source and template. In the mixing order, the P source and the Al source are mixed, and then the template is mixed. In that case, first, in the process of mixing the P source and the Al source (the process from the start of mixing the P source and the Al source to the start of mixing the template), when the time of the mixing process is 100%, 50% or more About the time of this, Preferably it mixes at the temperature of 40 degreeC or more and 70 degrees C or less about 70% or more of time. More preferably, mixing is performed at 50 ° C. or higher and 60 ° C. or lower. The reason for setting the mixing condition in the above range is that, if out of the above range, the mixing state becomes non-uniform due to an increase in viscosity, and the reaction between the Al source and the P source is not sufficiently promoted. This is because. Usually, it takes about 1.5 to 3 hours to obtain a uniform mixed state.

  Next, in the template mixing step (from the start of template mixing until the Al source, P source, Fe source and template are uniformly mixed), when the time of the mixing step is 100%, 50% or more About the time of this, Preferably about 70% or more of the time, the temperature of 5 to 45 degreeC is hold | maintained by cooling operation. About temperature, Preferably it is 15 to 35 degreeC, More preferably, the temperature of 20 to 30 degreeC is hold | maintained. The reason for setting the mixing condition in the above range is that, if out of the above range, inconvenience such as by-product of impurities occurs. Usually, about 1 to 3 hours are required to obtain a uniform mixed state.

  Further, the order of mixing the Fe source is not particularly limited. Usually, the Fe source is mixed after the mixing step of the P source and the Al source. In this case, the mixture of the P source and the Al source is cooled in advance to the temperature range of the template mixing step by the cooling operation, and is mixed before the template mixing is started. In performing the Fe source mixing step and the template mixing step, the cooling means and the cooling rate are not particularly limited in the cooling operation, and various known cooling devices can be used.

The composition of the aqueous starting material, preferably the molar ratio of Fe with respect to _Al 2 _{O 3} when converted to Al source _Al 2 _{O 3} 0.1 to 0.3, and the molar ratio of the template It is 0.8 or more and 1.33 or less. More preferably, the molar ratio of Fe is 0.15 or more and 0.25 or less, and the molar ratio of the template is 0.9 or more and 1.2 or less. The reason for setting the molar ratio of Fe and template in the aqueous starting material in the above range is that, if these molar ratios are out of the above range, stirring cannot be performed due to the increase in viscosity accompanying the temperature rise during hydrothermal synthesis. In addition, problems such as by-product of impurities and significant adhesion of crystals to the inner wall of the reactor occur.

The lower limit of the ratio of water is usually 3 or more in terms of molar ratio with respect to Al ₂ O ₃ , and preferably 5 or more, more preferably 10 or more, from the viewpoint of ease of synthesis. On the other hand, the upper limit of the ratio of water is usually 200 or less in terms of molar ratio with respect to Al ₂ O ₃ , preferably 150 or less, more preferably 120 or less, from the viewpoint of ease of synthesis and high productivity. It is. Furthermore, the pH of the aqueous starting material is usually from 2 to 10, and preferably from 3 to 9, more preferably from 3.5 to 8.5, from the viewpoint of ease of synthesis.

  In addition, in each aqueous starting material, you may coexist components other than said component if desired. Examples of such components include hydrophilic organic solvents such as hydroxides and salts of alkali metals and alkaline earth metals, and alcohols.

  In the present invention, the composition of the aqueous starting material is calculated from the masses of the added P source, Al source, Fe source, and template material. The actual composition of the aqueous starting material can be confirmed by elemental analysis, for example.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited at all by the following examples. In the following examples and comparative examples, XRD measurement was performed under the following conditions.

  The particle size distribution was measured by a laser diffraction method using “LASER MICRON SIZE LMS-24” (trade name) manufactured by Seishin Enterprise Co., Ltd. At that time, a small amount of sample was dispersed in water and put into a measuring section, and automatic measurement was performed under the following conditions.

Example 1:
To a mixture of 243.6 g of water and 110.1 g of 85% phosphoric acid, 58.4 g of pseudoboehmite (containing 25% water, manufactured by Condea) was slowly added and stirred for 1.5 hours. An aqueous solution in which 26.6 g of ferrous sulfate heptahydrate was dissolved in 136.6 g of water was added thereto, and 67.6 g of triethylamine was further mixed and stirred for 1 hour. The gel was prepared without temperature control, and a starting reaction product having the following composition was obtained.

Next, the above starting reactant was charged into a 1 liter stainless steel autoclave charged with a Teflon (registered trademark) inner cylinder, and reacted at a stirring linear velocity of 0.60 m / s and a temperature of 180 ° C. for 12 hours. After completion of the reaction, the steam in the autoclave was purged and cooled, and the solid content was recovered by centle filtration. The solid content was washed by sprinkling 200 ml of water and dried at 90 ° C. The yield was 108.2g. Subsequently, 1.5 g of the obtained template-containing sample was collected, put into a vertical quartz fired tube, and 1.5 ° C. under a stream of 5% O 2/95% N ₂ mixed gas supplied at 30 ml / min. The temperature was raised to 550 ° C. at a rate of temperature rise / minute, and calcination was carried out for 6 hours while maintaining 550 ° C. When the XRD of the crystalline aluminophosphate thus obtained was measured, it was an AFI type FAPO-5.

  The above FAPO-5 was dispersed in water and the average particle size was determined by a particle size distribution meter. As a result, the average particle size was 6.9 μm. Further, “Belsoap 18” (trade name) manufactured by Nippon Bell Co., Ltd. was used as an adsorption isotherm measuring device, and the water vapor adsorption isotherm at 35 ° C. of the above FAPO-5 was measured. As a result, the difference in adsorption amount between the relative humidity of 0.14 and 0.3 was 0.155 g / g. The adsorption isotherm was measured at an air high temperature bath temperature of 55 ° C., an adsorption temperature of 35 ° C., an initial introduction pressure of 0.400 kPa, an introduction pressure set point of 0, a saturated vapor pressure of 5.622 kPa, and an equilibrium time of 500 seconds.

Example 2:
In Example 1, a mixture of water and 85% phosphoric acid was heated to 50 ° C., pseudoboehmite was added, and gel adjustment was performed while maintaining the temperature at 50 ° C., and the same composition as in Example 1 was obtained. The starting reactant was obtained.

  The same operation as in Example 1 was performed except that the above starting reactant was reacted at a stirring linear velocity of 0.62 m / s (the yield of the sample containing the template after drying was 105.2 g. ) When the XRD of the obtained crystalline aluminophosphate was measured, it was AFI type FAPO-5. As a result of dispersing this in water and obtaining the average particle size with a particle size distribution meter, the average particle size was 6.3 μm.

  Further, the water vapor adsorption isotherm at 35 ° C. of the above zeolite was measured by an adsorption isotherm measuring device. As a result, the difference in adsorption amount between 0.14 and 0.3 relative humidity was 0.163 g / g.

Example 3:
In Example 2, pseudoboehmite was added and stirred for 1.5 hours, and then the same operation was performed except that the mixture was cooled to 25 ° C., thereby obtaining a starting reactant having the same composition as in Example 2. Subsequently, operation similar to Example 1 was performed with respect to said starting reaction material, and solid content was collect | recovered. The yield of the template-containing sample after drying was 94.7 g. And solid content was baked like Example 1, and the crystalline aluminophosphate was obtained. And when XRD of the obtained crystalline aluminophosphate was measured, it was AFI type so-called FAPO-5.

  The above FAPO-5 was dispersed in water, and the average particle size was determined by a particle size distribution meter. As a result, the average particle size was 5.2 μm. Further, as in Example 1, the water vapor adsorption isotherm at 35 ° C. was measured. As a result, the difference in adsorption amount between 0.14 and 0.3 was 0.153 g / g.

Example 4:
The same operation as in Example 2 was carried out except that the amount of triethylamine to be added was changed to 58.0 g to obtain a starting reaction product having the following composition.

  Next, the same operation as in Example 2 was performed except that the starting reactant was reacted at a stirring linear velocity of 0.94 m / s, and the solid content was recovered. The yield of the template-containing sample after drying was 119.2 g. And solid content was baked like Example 1, and the crystalline aluminophosphate was obtained. When the XRD of the obtained crystalline aluminophosphate was measured, it was AFI type FAPO-5.

  As a result of dispersing the above FAPO-5 in water and obtaining the average particle size by a particle size distribution meter, the particle size distribution was as shown in FIG. 1, and the average particle size was 4.0 μm. Moreover, when SEM "S-4100" (brand name) by Hitachi, Ltd. was used and the particle | grains were observed, the observation image (magnification x6000) of particle | grains was as showing in FIG. Furthermore, as in Example 1, the water vapor adsorption isotherm at 35 ° C. was measured. As a result, the water vapor adsorption isotherm was as shown in FIG. 3, and the difference in adsorption amount between the relative humidity of 0.14 and 0.3 was 0. 164 g / g.

Comparative Example 1:
The same operation as in Example 4 was performed to obtain a starting reactant having the same composition as in Example 4. Subsequently, the same operation as in Example 4 was performed on the starting reactant except that the reaction was performed at a linear stirring speed of 0.040 m / s, and the solid content was recovered. The yield of the template-containing sample after drying was 105.4 g. And solid content was baked like Example 1, and the crystalline aluminophosphate was obtained. When the XRD of the obtained crystalline aluminophosphate was measured, it was AFI type FAPO-5.

  The above-mentioned FAPO-5 was dispersed in water, and the average particle size was determined by a particle size distribution meter. As a result, the particle size distribution was as shown in FIG. 4, and the average particle size was 27.6 μm. Further, as in Example 1, the water vapor adsorption isotherm at 35 ° C. was measured. As a result, the water vapor adsorption isotherm was as shown in FIG. 5, and the difference in adsorption amount between the relative humidity of 0.14 and 0.3 was 0. It was 167 g / g.

Comparative Example 2:
A mixture of 210.7 g of water and 83.7 g of 85% phosphoric acid was heated to 50 ° C., and 56.4 g of pseudoboehmite (containing 25% water, manufactured by Condea) was slowly added thereto. After stirring for 3 hours, 6.2 g of fumed silica (trade name; Aerosil 200) and 210.7 g of water were mixed, and 32.5 g of morpholine and 42.0 g of triethylamine were further mixed and stirred for 1 hour. A starting reaction with was obtained.

  Subsequently, the same operation as in Example 1 was carried out except that the above starting reactant was reacted at a stirring linear velocity of 0.40 m / s for 48 hours to recover a solid content. The yield of the template-containing sample after drying was 70.6 g. Then, the solid content was calcined in the same manner as in Example 1 to obtain zeolite. When the XRD of the obtained zeolite was measured, it was a so-called SAPO-34 of the CHA type. And this was disperse | distributed to water, As a result of calculating | requiring an average particle diameter with the particle size distribution analyzer, the average particle diameter was 15.6 micrometers.

Comparative Example 3:
The same operation as in Comparative Example 2 was performed to obtain the same starting reactant as in Comparative Example 2. Subsequently, the same operation as in Example 1 was carried out except that the starting reactant was reacted at a stirring linear velocity of 0.94 m / s for 48 hours to recover a solid content. The yield of the sample containing the template after drying was 71.2 g. Then, the solid content was calcined in the same manner as in Example 1 to obtain zeolite. When the XRD of the obtained zeolite was measured, it was a so-called SAPO-34 of the CHA type. And this was disperse | distributed to water, As a result of calculating | requiring an average particle diameter with the particle size distribution analyzer, the average particle diameter was 16.4 micrometers.

Comparative Example 4:
A mixture of 239.8 g of water and 110.1 g of 85% phosphoric acid was heated to 50 ° C., and 58.4 g of pseudoboehmite (containing 25% water, manufactured by Condea) was slowly added thereto and stirred for 1.5 hours. After cooling this to 25 ° C., an aqueous solution in which 39.8 g of ferrous sulfate heptahydrate was dissolved in 140.8 g of water was added, and 67.6 g of triethylamine was further mixed and stirred for 1 hour. A starting reactant having the following composition was obtained:

  Subsequently, the same operation as in Example 1 was carried out except that the above starting reactant was reacted at a stirring linear velocity of 0.84 m / s to recover the solid content. The yield of the template-containing sample after drying was 77.9 g. Then, the solid content was calcined in the same manner as in Example 1 to obtain zeolite. When the XRD of the obtained zeolite was measured, it was an AFI type FAPO-5. And this was disperse | distributed to water, As a result of calculating | requiring an average particle diameter with the particle size distribution analyzer, the average particle diameter was 12.1 micrometers. Further, as in Example 1, the water vapor adsorption isotherm at 35 ° C. was measured. As a result, the water vapor adsorption isotherm was as shown in FIG. 6, and the difference in adsorption amount between the relative humidity of 0.14 and 0.3 was 0. 150 g / g.

  Further, the above FAPO-5 was pulverized with a jet mill to have an average particle size of 5.1 μm. As in Example 1, the water vapor adsorption isotherm at 35 ° C. was measured. As a result, the water vapor adsorption isotherm was as shown in FIG. 6, and the difference in adsorption amount between the relative humidity of 0.14 and 0.3 was 0. 132 g / g. FIG. 6 shows water vapor adsorption isotherms before and after pulverization by a jet mill.

Example 1 is data in which it is verified that the requirement of claim 3 may be satisfied without satisfying the requirement of claim 4 (specifically, the temperature condition of the mixing step of the P source and the Al source). . In addition, Example 2 is data in which it is verified that the requirements of claims 3 and 4 may be satisfied even if the requirements of claim 6 (specifically, the molar ratio between specific raw materials) are not satisfied. Example 4 is data when the requirement of claim 6 is satisfied.

4 is a graph showing the particle size distribution of zeolite (FAPO-5) obtained in Example 4. It is a SEM observation image (drawing substitute photograph) of the zeolite (FAPO-5) particles obtained in Example 4. 4 is a water vapor adsorption isotherm of zeolite (FAPO-5) obtained in Example 4. FIG. 2 is a graph showing the particle size distribution of zeolite (FAPO-5) obtained in Comparative Example 1. 3 is a water vapor adsorption isotherm of zeolite (FAPO-5) obtained in Comparative Example 1. FIG. It is a water vapor adsorption isotherm before and after grinding of the zeolite (FAPO-5) obtained in Comparative Example 4.

Claims (6)

  An AFI type iron aluminophosphate of fine particles obtained without mechanical pulverization, wherein the average particle size is 15 microns or less.   2. The AFI type iron aluminophosphate according to claim 1, wherein a difference in adsorption amount at a relative humidity of 0.14 and 0.3 in a water vapor adsorption isotherm at 35 ° C. is 0.14 g / g or more.   The method for producing an AFI type iron aluminophosphate according to claim 1 or 2, wherein hydrothermal synthesis of an aqueous starting material containing a P source, an Al source, an Fe source and a template is 0.05 m / s or more. A method for producing an AFI type iron aluminophosphate, characterized by stirring at a stirring linear velocity.   A method for producing an AFI type iron aluminophosphate including a template mixing step after a P source and Al source mixing step, wherein the temperature is 40 ° C. or higher and 70 ° C. or lower for a time of 50% or more of the P source and Al source mixing step. The method for producing an AFI type iron aluminophosphate according to claim 3, wherein the mixing is performed at a temperature of 5 ° C.   A method for producing an AFI type iron aluminophosphate including a template mixing step after a P source and Al source mixing step, and a temperature of 5 ° C. or higher and 45 ° C. or lower by a cooling operation for a time of 50% or more of the template mixing step. The manufacturing method of the AFI type iron aluminophosphate of Claim 3 or 4 which hold | maintains. P source, Al source, the composition of the aqueous starting material obtained by mixing Fe source and a template, the molar ratio of Fe with respect to _Al 2 _{O 3} when converted to Al source _Al 2 _{O 3} is 0.1 or more 0 The method for producing an AFI type iron aluminophosphate according to any one of claims 3 to 5, wherein the molar ratio of the template is 0.8 or more and 1.33 or less.

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