AFR structure aluminum phosphate molecular sieve and synthesis method and application thereof

Abstract

The invention discloses an AFR structure aluminophosphate molecular sieve as well as a synthesis method and application thereof. Comprising the following steps: mixing an aluminum source, water, a phosphorus source, a template SDA and a substance A to obtain initial gel, wherein the substance A is a seed crystal and / or hydrofluoric acid; crystallizing the initial gel under a closed condition to obtain aluminum phosphate AlPO-40 molecular sieve raw powder with an AFR structure; the molar ratio of the aluminum source to the water to the phosphorus source to the template SDA to the hydrofluoric acid to the seed crystal is (0.5-1.5): (10-120): (0.5-1.5): (0.25-2.0): (0-1.0); the adding amount of the seed crystal is 0-20wt% of the total amount of Al2O3 and P2O5; at least one of hydrofluoric acid and seed crystal is added. The aluminum phosphate AlPO-40 with the AFR structure synthesized by the invention is high in crystallinity and high in yield; the adsorbent is used for adsorbing heat storage materials, heat pump materials, refrigeration materials or adsorption separation gas, the effect is good, operation is easy and convenient, and cost is low.

Description

Technical Field

[0001] The invention belongs to the field of material technology, and in particular relates to an AFR structure aluminum phosphate molecular sieve and a synthesis method and application thereof. Background Art

[0002] Molecular sieves are a type of inorganic solid material with a regular pore structure, which is widely used in catalysis, adsorption separation, ion exchange and other fields. Aluminum phosphate molecular sieves (AlPOs) are an important member of molecular sieves, originated from Union Carbide Corp in 1982. With its rich pore structure, adjustable pore size and excellent hydrothermal stability, the neutral framework AlPO molecular sieve has performed well in the fields of gas adsorption separation, adsorption heat pumps and refrigeration materials. The AlPO molecular sieve structure is a three-dimensional network formed by alternating tetrahedrons [AlO4] and [PO4] connected by oxygen atom bridges. Therefore, the Al / P atomic ratio of AlPO molecular sieve is usually 1, and the framework is not acidic.

[0003] At present, the synthesis method of AlPO-40 (AFR configuration, 12 / 8 / 6 / 4-membered ring) reported in the literature requires three templates: tetrapropylammonium hydroxide (TPAOH), tetrapropylammonium bromide (TPABr) and tetramethylammonium hydroxide (TMAOH) (JP Lourenco, MF Ribeiro, FR Ribeiro, et al., Synthesis, characterization, and catalytic properties of AlPO4-40, CoAPO-40, and ZnAPO-40, Zeolites, 1997, 18, 398-407), and requires a long crystallization time, the crystallization system is unstable, the experimental repeatability is poor, and it is difficult to obtain high-quality AlPO-40 products. Compared with AlPO-40, SAPO-40 (AFR configuration) with silicoaluminophosphate composition is more stable and can be used in fields such as glycerol dehydration (A. Fernandes, M. Filipa Ribeiro and JP Gas-phase dehydration of glycerol over hierarchical silicoaluminophosphate SAPO-40, Catalysis Communications, 2017, 95, 16-20), but it needs to be crystallized at 200°C for more than 120 hours to obtain. Summary of the invention

[0004] In view of this, the present invention provides an AFR structure aluminum phosphate molecular sieve and a synthesis method and application thereof, the main purpose of which is to solve the problems of long molecular sieve synthesis cycle and unstable product quality.

[0005] In one aspect, the present invention provides a method for synthesizing an AFR structure aluminum phosphate molecular sieve, the method comprising the following steps:

[0006] S1: mixing an aluminum source, water, a phosphorus source, a template agent SDA and a substance A to obtain an initial gel; wherein SDA is tetrapropylammonium compound, and substance A is a seed crystal and / or hydrofluoric acid;

[0007] S2: the initial gel in step S1 is crystallized under closed conditions to obtain aluminum phosphate AlPO-40 molecular sieve raw powder with AFR structure;

[0008] The mixing ratio of the aluminum source, water, phosphorus source, template agent SDA, hydrofluoric acid and seed crystal in the initial gel is:

[0009] Al2O3:H2O:P2O5:SDA:HF=0.5~1.5:10~120:0.5~1.5:0.25~2.0:0~1.0, in molar ratio;

[0010] The amount of the seed crystal added is 0 to 20 wt % of the total mass of Al2O3 and P2O5 in the initial gel; and at least one of hydrofluoric acid and seed crystal is added.

[0011] The inventors found in the research of synthesizing AlPO-40 molecular sieve that HF ​​is more inclined to guide the secondary structure sti of AlPO-40 molecular sieve in the above initial gel system, and the seed crystal also has the above guiding effect and its guiding ability is stronger and more specific than HF.

[0012] The present invention includes the following three methods of adding hydrofluoric acid and seed crystals on the basis of aluminum source, water, phosphorus source and template agent SDA:

[0013] (1) Only hydrofluoric acid is added without adding seed crystals;

[0014] (2) Only adding seed crystals without adding hydrofluoric acid;

[0015] (3) Add hydrofluoric acid and seed crystals.

[0016] Optionally, in step S1, when the substance A is a seed crystal, the molar ratio of the aluminum source, water, phosphorus source, template agent SDA and co-template agent co-SDA in the initial gel is:

[0017] Al2O3: H2O: P2O5: SDA: co-SDA=0.5~1.5: 10~120: 0.5~1.5: 0.25~2.0: 0~2.0;

[0018] Wherein, co-SDA is an organic amine reagent different from SDA;

[0019] The mole number of the aluminum source is calculated as the mole number of Al2O3, the mole number of water is calculated as the mole number of H2O itself, the mole number of the phosphorus source is calculated as the mole number of P2O5, the mole number of the template SDA is calculated as the mole number of SDA itself, and the mole number of the co-template co-SDA is calculated as the mole number of itself;

[0020] The amount of the seed crystal added is 1 to 20 wt % of the total mass of Al 2 O 3 and P 2 O 5 in the initial gel.

[0021] Optionally, the amount of the seed crystal added is selected from any value among 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt% or any range value between two of them in the total mass of Al2O3 and P2O5 in the initial gel.

[0022] Optionally, the added amount of the seed crystals is 5 to 20 wt % of the total mass of Al 2 O 3 and P 2 O 5 in the initial gel.

[0023] Optionally, the seed crystals are selected from AlPO-40 seed crystals.

[0024] Optionally, in step S1, the template agent SDA is selected from at least one of tetrapropylammonium hydroxide, tetrapropylammonium bromide, tetrapropylammonium chloride, tetrapropylammonium iodide and tetrapropylammonium fluoride.

[0025] Optionally, in step S1, when the template agent SDA is tetrapropylammonium hydroxide, the molar ratio of the aluminum source, water, phosphorus source and template agent SDA in the initial gel is:

[0026] Al2O3: H2O: P2O5: SDA=0.5~1.5: 10~120: 0.5~1.5: 1.0~2.0.

[0027] That is, when SDA is TPAOH and the molar ratio is not less than 1.0, co-SDA may not be added.

[0028] Optionally, in step S1, when the template agent SDA is at least one of tetrapropylammonium bromide, tetrapropylammonium chloride, tetrapropylammonium iodide and tetrapropylammonium fluoride, the molar ratio of the aluminum source, water, phosphorus source, template agent SDA and co-template agent co-SDA in the initial gel is:

[0029] Al2O3: H2O: P2O5: SDA: co-SDA=0.5~1.5: 10~120: 0.5~1.5: 0.25~2.0: 0.5~2.0.

[0030] That is, when SDA is selected from one or more combinations of TPACl, TPABr, TPAI, and TPAF, the molar ratio of co-SDA is not less than 0.5.

[0031] Optionally, in step S1, the co-template agent co-SDA is selected from at least one of dimethylamine, trimethylamine, diethylamine, triethylamine, propylamine, dipropylamine, tripropylamine, diisopropylamine, n-butylamine, morpholine, piperazine, tetramethylethylenediamine, cyclohexylamine, cycloheximide, diethanolamine and 1-[2-(2-hydroxyethoxy)ethyl]piperazine.

[0032] Optionally, in step S2, the crystallization temperature is 120-200° C., the crystallization time is 1-24 h, and the crystallization method is dynamic or static.

[0033] Optionally, in step S1, the aluminum source, the water, the phosphorus source and the template agent SDA are premixed and stirred for 1 to 3 hours to obtain a mixture I; the mixture I is then mixed with the seed crystal and the co-template agent co-SDA and stirred for 1 to 3 hours to obtain an initial gel.

[0034] Optionally, in step S1, when the substance A is hydrofluoric acid, the molar ratio of the aluminum source, water, phosphorus source, template agent SDA and hydrofluoric acid in the initial gel is:

[0035] Al2O3: H2O: P2O5: SDA: HF=0.5~1.5: 10~120: 0.5~1.5: 0.5~2.0: 0.1~1.0;

[0036] The molar number of the aluminum source is calculated as the molar number of Al2O3, the molar number of water is calculated as the molar number of H2O itself, the molar number of the phosphorus source is calculated as the molar number of P2O5, the molar number of the template SDA is calculated as the molar number of SDA itself, and the molar number of hydrofluoric acid is calculated as the molar number of HF itself;

[0037] The amount of seed crystal added is 0 to 20 wt % of the total mass of Al2O3 and P2O5 in the initial gel.

[0038] Optionally, the added amount of the seed crystals is 1 to 20 wt% of the total mass of Al2O3 and P2O5 in the initial gel; and the seed crystals are selected from AlPO-40 seed crystals.

[0039] Optionally, the template agent SDA is tetrapropylammonium hydroxide.

[0040] Optionally, in step S2, the crystallization temperature is 120-200° C., the crystallization time is 12-96 hours, and the crystallization method is dynamic or static.

[0041] Optionally, in step S1, the aluminum source is selected from at least one of pseudo-boehmite, alumina, aluminum hydroxide, metaaluminate, aluminum isopropoxide, aluminum sec-butoxide, aluminum phosphate, aluminum chloride and aluminum nitrate.

[0042] Optionally, in step S1, the phosphorus source is selected from at least one of orthophosphoric acid, phosphorous acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, phosphorus oxides, organophosphorus reagents and aluminum phosphate.

[0043] Optionally, in step S2, the AlPO-40 molecular sieve raw powder is calcined in an air atmosphere at a temperature of 450-800° C. to remove the template.

[0044] The present invention provides a specific method I for synthesizing AlPO-40 molecular sieve:

[0045] 1) Premixing an aluminum source, water, a phosphorus source, tetrapropylammonium hydroxide (TPAOH), hydrofluoric acid and seed crystals to obtain an initial gel, wherein the molar ratio of the initial gel is Al2O3:H2O:P2O5:TPAOH:HF=0.5-1.5:10-120:0.5-1.5:0.5-2.0:0.2-1.0, and the amount of seed crystals used is 0-20wt% of the sum of the mass of Al2O3 and P2O5 in the initial gel;

[0046] 2) The mixture is packaged into a reaction kettle and crystallized at 120-200° C. for 12-96 hours. The obtained product is washed, centrifuged and dried to obtain AlPO-40 raw powder.

[0047] Optionally, the aluminum source in step 1) is a combination of one or more of pseudo-boehmite, alumina, aluminum hydroxide, metaaluminate, aluminum isopropoxide, aluminum sec-butoxide, aluminum phosphate, aluminum chloride, and aluminum nitrate.

[0048] The aluminum source is preferably a combination of one or more of pseudo-boehmite, aluminum hydroxide, aluminum isopropoxide and aluminum oxide.

[0049] Optionally, the phosphorus source in step 1) is selected from one or more of orthophosphoric acid, phosphorous acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, phosphorus oxides, organophosphorus reagents, and aluminum phosphate.

[0050] The phosphorus source is preferably orthophosphoric acid.

[0051] Optionally, the TPAOH in step 1) can be partially replaced by a corresponding salt, such as tetrapropylammonium chloride (TPACl), tetrapropylammonium bromide (TPABr), tetrapropylammonium iodide (TPAI) or tetrapropylammonium fluoride (TPAF), but the amount of TPAOH is not less than 0.5.

[0052] Optionally, the seed crystal may not be added in step 1). The yield of the synthesis without adding the seed crystal is about 20 wt% lower than that of the synthesis with adding the seed crystal.

[0053] Preferably, the crystallization temperature in step 2) is preferably 140-180°C.

[0054] Preferably, the crystallization time in step 2) is preferably 72-96 hours.

[0055] Preferably, the crystallization method in step 2) is preferably dynamic crystallization.

[0056] The present invention also provides a specific method II for synthesizing AlPO-40 molecular sieve:

[0057] a) According to Al2O3:H2O:P2O5:TPA + The initial gel is prepared with a molar ratio of :co-SDA=0.5-1.5:10-120:0.5-1.5:0.25-2.0:0-2.0, and the amount of seed crystals is 1-20wt% of the sum of the mass of Al2O3 and P2O5 in the initial gel. First, aluminum source, water, phosphoric acid and TPA are added + , stir evenly and then add seed crystals and co-SDA;

[0058] b) After mixing all materials evenly, transfer them to a reaction kettle and crystallize them at 120° C.-200° C. for 1-24 hours, and then wash, separate and dry the product.

[0059] Optionally, the co-SDA in step a) can be selected from a combination of one or more of dimethylamine, trimethylamine, diethylamine, triethylamine, tetrapropylammonium hydroxide, propylamine, dipropylamine, tripropylamine, diisopropylamine, n-butylamine, morpholine, piperazine, pyridine, tetramethylethylenediamine, cyclohexylamine, cycloheximide, diethanolamine and 1-[2-(2-hydroxyethoxy)ethyl]piperazine.

[0060] The co-SDA in step a) is preferably a combination of one or more of diethylamine, trimethylamine, tetramethylethylenediamine and triethylamine.

[0061] Optionally, the TPA in step a) + is selected from one or a combination of TPAOH, TPACl, TPABr, TPAI, and TPAF.

[0062] Preferably, when the TPA in step a) + When one or more combinations are selected from TPACl, TPABr, TPAI, and TPAF, the molar ratio of co-SDA is not less than 0.5.

[0063] Optionally, when the TPA in step a) + It is TPAOH and the molar ratio is not less than 1.0, and co-SDA may not be added.

[0064] Optionally, the seed crystals in step a) may be obtained through steps 1) and 2), may come from steps a) and b), or may be seed crystals calcined at high temperature.

[0065] Preferably, the amount of seed crystals used in step a) is not less than 5 wt %.

[0066] The crystallization temperature in step b) is preferably 140-180°C.

[0067] The crystallization time in step b) is preferably 2-12 hours.

[0068] The crystallization method in step b) is preferably dynamic crystallization.

[0069] In a second aspect, the present invention provides an AFR structure aluminum phosphate molecular sieve, which is an AlPO-40 molecular sieve synthesized by the above method.

[0070] In a third aspect, the present invention provides a molecular sieve synthesized by the above method or the use of the molecular sieve in adsorption heat storage materials, heat pump materials, refrigeration materials or gas adsorption separation.

[0071] Compared with the prior art, the present invention has the following beneficial effects:

[0072] 1) The present invention successfully synthesized an aluminum phosphate AlPO-40 molecular sieve with high purity, high crystallinity, and a flaky crystalline morphology with a thickness of about 2.0 to 3.0 μm.

[0073] 2) The present invention synthesizes aluminum phosphate molecular sieve AlPO-40 having an AFR structure, has various methods, is simple to operate, has low cost, and uses commercially available raw materials, which is suitable for industrial production;

[0074] 3) The aluminum phosphate molecular sieve AlPO-40 with an AFR structure synthesized by the present invention can be used for adsorption heat storage materials, heat pump materials, refrigeration materials or adsorbents to separate gases, with good effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 The XRD patterns of the products of Examples 1-3 of the present invention;

[0076] Figure 2This is a SEM photo of the product of Example 1 of the present invention;

[0077] Figure 3 is the nitrogen physical adsorption isotherm measured after calcination of Examples 1-3 of the present invention;

[0078] Figure 4 This is a SEM photo of Example 2 of the present invention;

[0079] Figure 5 This is a SEM photo of Example 3 of the present invention;

[0080] Figure 6 It is the XRD diagram of comparative examples 1-3 of the present invention. DETAILED DESCRIPTION

[0081] The present application is further described below in conjunction with specific embodiments. The following are only a few embodiments of the present application, and are not intended to limit the present application in any form. Although the present application discloses the following preferred embodiments, they are not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the above disclosed technical content to make some changes or modifications are equivalent to equivalent implementation cases and are within the scope of the technical solution.

[0082] The chemical reagents used in the embodiments of the present invention can be purchased through commercial channels without secondary purification. The English abbreviations of the chemical reagents used in the embodiments are as follows:

[0083] Morpholine (Mor), diethylamine (DEA), triethylamine (TEA), dipropylamine (DPA), tetrapropylammonium hydroxide (TPAOH), tetrapropylammonium bromide (TPABr), tetrapropylammonium chloride (TPACl), tetrapropylammonium fluoride (TPAF).

[0084] The calculation formula for product yield in the embodiment is as follows:

[0085] Yield=0.75·m product / (m Al2O3 +m P2O5 +m seed )×100%;

[0086] 0.75—Empirical value of sample inorganic content obtained by thermogravimetric analysis;

[0087] m product —Quality of the raw powder product obtained after washing, separation and drying;

[0088] m Al2O3 —The mass of Al2O3 corresponding to the aluminum source in the initial gel;

[0089] m P2O5—The mass of P2O5 corresponding to the phosphorus source in the initial gel;

[0090] m seed —The mass of the seeds introduced into the initial gel.

[0091] The amount of seed crystals introduced in all embodiments of the present invention is uniformly expressed as x·m(Al2O3+P2O5), wherein x represents the ratio of the added seed crystals to the total mass of Al2O3 and P2O5 in the initial gel, and m(Al2O3+P2O5) is the sum of the masses of the corresponding Al2O3 and P2O5 in the initial gel. The amount of seed crystals introduced in the embodiments is represented only by x.

[0092] The crystal structure of the product of the present invention is identified by powder X-ray diffraction (XRD) results. The XRD test instrument is an X'Pert PRO X-ray diffraction analyzer manufactured by PANalytical of the Netherlands, with a Cu target, a Kα emission source (wavelength 0.15418 nm), and operating parameters of 40 kV voltage and 40 mA current.

[0093] The elemental composition analysis of the samples of the present invention was determined by a Magix 601X X-ray fluorescence analyzer (XRF) of Philips of the Netherlands. The sample morphology was obtained by a scanning electron microscope (SEM), and the testing instrument was a Hitachi SU8020 field emission scanning electron microscope (FE-SEM) with an acceleration voltage of 2KV.

[0094] The specific surface area, pore volume and other parameters of the sample of the present invention are obtained by using the ASAP 2020 physical adsorption instrument of Micromeritics Company of the United States. The high-temperature calcined sample is vacuum treated at 350°C for 4 hours, and the effective volume of the sample tube is determined by He. N2 is the adsorbed gas. Physical adsorption and desorption experiments are carried out in a liquid nitrogen (77K) environment. The specific surface area of ​​the sample is calculated using the BET equation. The total pore volume of the sample is estimated by the N2 adsorption amount at a relative pressure (P / P0) of 0.99. The t-plot model is used to obtain the micropore surface area and volume. The cross-sectional area of ​​the N2 molecule is 0.162nm 2 , the surface area, volume and diameter of the pores were obtained by the BET-BJH method.

[0095] Example 1 (TPAOH+HF)

[0096] The molar ratio of the initial gel is Al2O3:H2O:P2O5:TPAOH:HF=1.0:100:1.0:1.0:0.4. Aluminum hydroxide (99%), water, TPAOH (25% aqueous solution) and phosphoric acid (85% H3PO4) are first stirred and mixed for about 2 hours, and then HF is added and stirred for about 2 hours. The uniformly mixed initial gel is transferred to a reactor with a polytetrafluoroethylene lining, packaged and placed at 130°C for crystallization for 72 hours. The crystallized product is washed, separated and dried to obtain the AlPO-40 raw powder with a yield of 42%. The product can be used as a seed for the subsequent synthesis of AlPO-40.

[0097] The XRD spectrum of the obtained product ( Figure 1 ) showed strong diffraction signals near 2θ=7.686°, 8.186°, 13.868°, 24.000°, 27.636°, and no other impurity signals appeared. SEM results ( Figure 2 ) shows that the product has a uniform morphology, presenting a 3.0μm×1.5μm×0.3μm flake morphology, which proves that the product is pure phase AlPO-40. XRF results show that F / (Al2O3+P2O5+F) in the product is 1.9wt%. After the product was calcined at 600℃ for 6h in air atmosphere, N2 physical adsorption analysis was tested ( Figure 3 ), calculate S BET =596.5m 2 / g,S micro =440.4m 2 / g,V total =0.3542cm 3 / g,V micro =0.2227cm 3 / g.

[0098] Example 2 (TPAOH+DEA+seed)

[0099] The initial gel was prepared according to the molar ratio of Al2O3:H2O:P2O5:TPAOH:DEA=1.0:120.0:1.0:0.25:1.5, and AlPO-40 seed crystals with x=0.2 (obtained in Example 1) were added. Aluminum isopropoxide (99%), water, TPAOH (25% aqueous solution) and phosphoric acid (85% H3PO4) were first mixed and stirred for about 3 hours, and then the seed crystals and DEA were added, and stirred for about 1 hour. After stirring evenly, the mixture was transferred to a reactor and crystallized at 180°C for about 4 hours. The product was washed, separated and dried to obtain molecular sieve raw powder with a yield of 64%.

[0100] The obtained product was subjected to XRD ( Figure 1) for phase identification, which is consistent with the results of Example 1. The SEM results ( Figure 4 ) shows a 3.0μm×1.5μm×0.15μm flake morphology, proving to be a pure phase product of AlPO-40. After the sample was calcined at 600℃ for 6h in air atmosphere, the N2 adsorption results ( Figure 3 ) is: S BET =507.8m 2 / g,S micro =315.6m 2 / g,V total =0.4204cm 3 / g,V micro =0.1595cm 3 / g.

[0101] Example 3 (TPAOH + seed crystal)

[0102] The initial gel was prepared according to the molar ratio of Al2O3:H2O:P2O5:TPAOH=1.0:40.0:1.0:1.7, the seed introduction amount x=0.1 (obtained in Example 1), and the initial gel was prepared in the order of adding pseudo-boehmite (67.5% Al2O3), water, TPAOH (40%), and orthophosphoric acid (85% H3PO4). All raw materials were stirred and mixed for about 2 hours, transferred to a reactor, and crystallized at 180°C for about 4 hours. After washing, separation and drying, the product was obtained to obtain AlPO-40 raw powder with a yield of 61%.

[0103] XRD results of the samples ( Figure 1 ) is consistent with the results of Example 1, and the SEM results ( Figure 5 ) showed flakes of about 2.0-3.0 μm, proving to be pure AlPO-40. After the sample was calcined at 600℃ for 6h in air atmosphere, the N2 adsorption results ( Figure 3 ) is: S BET =512.5m 2 / g,S micro =344.4m 2 / g,V total =0.4081cm 3 / g,V micro =0.1743cm 3 / g.

[0104] Examples 4 to 12 (TPA + + Seed)

[0105] The molar ratio, raw material type, crystallization conditions and other parameters of the initial gel of Examples 4-14 are shown in Table 1. After phase identification by XRD, the products are all AlPO-40.

[0106] The initial gel configuration of Examples 4-6 is similar to that of Example 3 (TPAOH+seed or TPAOH+seed+HF), and the initial gel configuration of Examples 7-14 refers to that of Example 2 (TPAOH+DEA+seed). Among them, Example 4 adopts a static crystallization method, and Examples 5 to 14 adopt a dynamic crystallization method; the seeds of Example 5 are obtained from the AlPO-40 raw powder of Example 1 after calcination; the seeds of Example 6 are the AlPO-40 raw powder obtained in Example 2; the seeds of Example 7 are the AlPO-40 raw powder of Example 3, and the seeds added in the remaining Examples are by default from the molecular sieve raw powder obtained in Example 1.

[0107] Table 1. Raw material molar composition and crystallization conditions for the synthesis of AlPO-40 molecular sieve

[0108]

[0109] Comparative Example 1 (SDA)

[0110] Referring to the method provided in the literature (JP Losenco, M F Ribeiro, F R Ribeiro, et al., Synthesis, characterization, and catalytic properties of AlPO4-40, CoAPO-40, and ZnAPO-40, Zeolites, 1997, 18, 398-407), the initial gel ratio is Al2O3: P2O5: TPAOH: TPABr: TMAOH: H2O = 0.8: 0.8: 0.952: 1.048: 0.040: 80.00, and the raw materials used are: pseudo-boehmite (77% Al2O3), orthophosphoric acid (85% H3PO4), tetrapropylammonium hydroxide (40% aqueous solution), tetrapropylammonium bromide (99%) and tetramethylammonium hydroxide (25% aqueous solution), static synthesis, crystallization at 150 ° C for 120h, only AlPO-5 ( Figure 6 ).

[0111] Comparative Example 2 (SDA)

[0112] Referring to the synthesis method of AlPO-40 provided in the literature (L. Sierra, J. Patarin and JL Guth, Synthesis of new aluminophosphate materials with the FAU and AFR structure-types, Microporous Materials, 1997, 11, 19-35), the initial gel molar ratio is Al2O3: P2O5: TPAOH: TPABr: TMAOH: H2O = 1.0: 1.0: 1.42: 0.52: 0.09: 75, and the raw materials are pseudo-boehmite (77% Al2O3), orthophosphoric acid (85% H3PO4), tetrapropylammonium hydroxide (40% aqueous solution), tetrapropylammonium bromide (99%) and tetramethylammonium hydroxide (40% aqueous solution). The above raw materials are mixed evenly to form an initial gel, which is transferred to a reactor and crystallized at 150°C for 23h. The product is a mixed phase of AlPO-40 and AlPO-5 ( Figure 6 ).

[0113] Comparative Example 3 (SDA)

[0114] The initial gel molar ratio was Al2O3:H2O:P2O5:TPAOH=1.0:40.0:1.0:1.7. The raw materials were pseudo-boehmite (77% Al2O3), orthophosphoric acid (85% H3PO4) and tetrapropylammonium hydroxide (40% aqueous solution). Referring to the configuration method of Example 3, the above raw materials were mixed evenly and transferred to a reactor. Crystallization was carried out at 180°C for 4h. After washing, centrifugation and drying, the XRD spectrum of the product showed that the AlPO-5 crystal phase was the main phase ( Figure 6 ).

[0115] By comparing the examples and comparative examples 1 to 3, it can be seen that in the ingredients for synthesizing aluminum phosphate molecular sieve AlPO-40 with an AFR structure of the present invention, when SDA is contained, when co-SDA is not contained, AlPO-40 can also be synthesized if the raw materials contain HF and / or seeds. If HF or seeds are not contained, it will be difficult to synthesize the AlPO-40 product.

[0116] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for synthesizing an AFR structure aluminum phosphate molecular sieve, characterized in that: The synthesis method comprises the following steps: S1: mixing an aluminum source, water, a phosphorus source, a template agent SDA and a substance A to obtain an initial gel; wherein SDA is tetrapropylammonium compound, and substance A is a seed crystal and / or hydrofluoric acid; S2: the initial gel in step S1 is crystallized under closed conditions to obtain aluminum phosphate AlPO-40 molecular sieve raw powder with AFR structure; The mixing ratio of the aluminum source, water, phosphorus source, template agent SDA, hydrofluoric acid and seed crystal in the initial gel is: Al2O3:H2O:P2O5:SDA:HF=0.5~1.5:10~120:0.5~1.5:0.25~2.0:0~1.0, in molar ratio; The amount of the seed crystal added is 0 to 20 wt % of the total mass of Al2O3 and P2O5 in the initial gel; and at least one of hydrofluoric acid and seed crystal is added.

2. The method for synthesizing an AFR structure aluminum phosphate molecular sieve according to claim 1, characterized in that: In step S1, when the substance A is a seed crystal, the molar ratio of the aluminum source, water, phosphorus source, template agent SDA and co-template agent co-SDA in the initial gel is: Al2O3:H2O:P2O5:SDA:co-SDA=0.5~1.5:10~120:0.5~1.5:0.25~2.0:0~2.0; Wherein, co-SDA is an organic amine reagent different from SDA; The mole number of the aluminum source is calculated as the mole number of Al2O3, the mole number of water is calculated as the mole number of H2O itself, the mole number of the phosphorus source is calculated as the mole number of P2O5, the mole number of the template SDA is calculated as the mole number of SDA itself, and the mole number of the co-template co-SDA is calculated as the mole number of itself; The amount of the seed crystal added is 1 to 20 wt % of the total mass of Al 2 O 3 and P 2 O 5 in the initial gel.

3. The method for synthesizing an AFR structure aluminum phosphate molecular sieve according to claim 2, characterized in that: The seed crystals are selected from AlPO-40 seed crystals; Preferably, in step S1, the template agent SDA is at least one selected from tetrapropylammonium hydroxide, tetrapropylammonium bromide, tetrapropylammonium chloride, tetrapropylammonium iodide and tetrapropylammonium fluoride.

4. The method for synthesizing an AFR structure aluminum phosphate molecular sieve according to claim 2, characterized in that: In step S1, when the template agent SDA is tetrapropylammonium hydroxide, the molar ratio of the aluminum source, water, phosphorus source and template agent SDA in the initial gel is: Al2O3:H2O:P2O5:SDA=0.5~1.5:10~120:0.5~1.5:1.0~2.

0.

5. The method for synthesizing an AFR structure aluminum phosphate molecular sieve according to claim 2, characterized in that: In step S1, when the template agent SDA is at least one of tetrapropylammonium bromide, tetrapropylammonium chloride, tetrapropylammonium iodide and tetrapropylammonium fluoride, the molar ratio of the aluminum source, water, phosphorus source, template agent SDA and co-template agent co-SDA in the initial gel is: Al2O3:H2O:P2O5:SDA:co-SDA=0.5~1.5:10~120:0.5~1.5:0.25~2.0:0.5~2.

0.

6. The method for synthesizing an AFR structure aluminum phosphate molecular sieve according to claim 2, characterized in that: In step S1, the co-template agent co-SDA is selected from at least one of dimethylamine, trimethylamine, diethylamine, triethylamine, propylamine, dipropylamine, tripropylamine, diisopropylamine, n-butylamine, morpholine, piperazine, tetramethylethylenediamine, cyclohexylamine, cycloheximide, diethanolamine and 1-[2-(2-hydroxyethoxy)ethyl]piperazine; Preferably, in step S2, the crystallization temperature is 120-200° C., the crystallization time is 1-24 hours, and the crystallization method is dynamic or static; Preferably, in step S1, the aluminum source, the water, the phosphorus source and the template agent SDA are premixed and stirred for 1 to 3 hours to obtain a mixture I; the mixture I is then mixed with the seed crystal and the co-template agent co-SDA and stirred for 1 to 3 hours to obtain an initial gel.

7. The method for synthesizing an AFR structure aluminum phosphate molecular sieve according to claim 1, characterized in that: In step S1, when the substance A is hydrofluoric acid, the molar ratio of the aluminum source, water, phosphorus source, template agent SDA and hydrofluoric acid in the initial gel is: Al2O3:H2O:P2O5:SDA:HF=0.5~1.5:10~120:0.5~1.5:0.5~2.0:0.1~1.0; The molar number of the aluminum source is calculated as the molar number of Al2O3, the molar number of water is calculated as the molar number of H2O itself, the molar number of the phosphorus source is calculated as the molar number of P2O5, the molar number of the template SDA is calculated as the molar number of SDA itself, and the molar number of hydrofluoric acid is calculated as the molar number of HF itself; The amount of seed crystal added is 0 to 20 wt % of the total mass of Al2O3 and P2O5 in the initial gel.

8. The method for synthesizing an AFR structure aluminum phosphate molecular sieve according to claim 7, characterized in that: The amount of the seed crystal added is 1 to 20 wt% of the total mass of Al2O3 and P2O5 in the initial gel; the seed crystal is selected from AlPO-40 seed crystal; Preferably, the template agent SDA is tetrapropylammonium hydroxide; Preferably, in step S2, the crystallization temperature is 120-200° C., the crystallization time is 12-96 hours, and the crystallization method is dynamic or static; Preferably, in step S1, the aluminum source is selected from at least one of pseudo-boehmite, alumina, aluminum hydroxide, metaaluminate, aluminum isopropoxide, aluminum sec-butoxide, aluminum phosphate, aluminum chloride and aluminum nitrate; Preferably, in step S1, the phosphorus source is selected from at least one of orthophosphoric acid, phosphorous acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, phosphorus oxides, organophosphorus reagents and aluminum phosphate; Preferably, in step S2, the AlPO-40 molecular sieve raw powder is calcined in an air atmosphere at a temperature of 450-800°C to remove the template.

9. An AFR structure aluminum phosphate molecular sieve, characterized in that: The molecular sieve is an AlPO-40 molecular sieve synthesized by the method described in any one of claims 1 to 8.

10. Use of the molecular sieve synthesized by the method according to any one of claims 1 to 8 or the molecular sieve according to claim 9 in adsorption heat storage materials, heat pump materials, refrigeration materials or gas adsorption separation.

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