Molecular sieve dnl-13, method for preparing the same, and use thereof

Abstract

The application discloses a molecular sieve DNL-13 and a preparation method and application thereof, and belongs to the technical field of molecular sieves. x R2(Si y Al 28‑y P 28 O 112 ) formula I; in formula I, R is an organic template agent, R is selected from 1,5-(N-triethyl) pentane diamine hydroxide; x is the mole number of H2O in each unit cell, x=0-10.0, y is the mole number of Si in each unit cell, y=0-2.0. The application synthesizes a novel framework structure phosphorus silicate aluminum molecular sieve, which can be used for adsorption separation and has high water adsorption; and the synthesis process is simple and has high operability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of molecular sieve, and particularly relates to a molecular sieve DNL-13 and a preparation method and application thereof. BACKGROUND

[0002] Phosphorus-aluminum molecular sieve is a phosphorus-aluminum salt with regular pore or cage structure, which is composed of phosphorus-oxygen tetrahedron and aluminum-oxygen tetrahedron connected by sharing oxygen. The phosphorus-aluminum molecular sieve family has a large number of members, mainly because the phosphorus or aluminum in the phosphorus-aluminum molecular sieve can be replaced by more than ten metals and non-metals to form metal phosphosilicic aluminum molecular sieve (MeAPO) and phosphosilicic aluminum molecular sieve (SAPO). These molecular sieves have very important applications in the fields of adsorption separation and catalysis.

[0003] The phosphorus-aluminum molecular sieve is generally synthesized by hydrothermal synthesis, and an organic template agent seems to be necessary. By designing and introducing different organic template agents, a variety of phosphorus-aluminum molecular sieves with novel structures have been synthesized, but compared with silicic-aluminum molecular sieves, there is still a great space for development. The lack of material types is also very disadvantageous to the microenvironment in the process of dissociative adsorption or catalysis. So far, only 46 kinds of phosphorus-aluminum molecular sieves have been published, and the potential and prospect of exploring phosphorus-aluminum molecular sieves are still very huge.

[0004] According to the pore dimension, the molecular sieve material can be divided into one-dimensional, two-dimensional and three-dimensional materials. Different pore dimensions and sizes also determine the application of the material in adsorption separation. According to the size of the pore, the molecular sieve material can be divided into small pore, medium pore, large pore and super large pore molecular sieve, which respectively has a window with 8-membered ring or less, 10-membered ring or less, 12-membered ring or less and more than 12-membered ring.

[0005] Three-dimensional phosphorus-aluminum molecular sieves have a very wide range of applications, but so far, three-dimensional 8*8*10 medium pore straight channel phosphorus-aluminum molecular sieves are still missing. Developing different pore types, expanding the AlPO molecular sieve family, and exploring the microprocess in the synthesis process are challenges faced by researchers. SUMMARY

[0006] In view of this, the present application provides a molecular sieve DNL-13 and a preparation method and application thereof, and the main purpose is to solve the technical problem of developing three-dimensional 8*8*10 medium pore straight channel phosphorus-aluminum molecular sieves and expanding different pore types.

[0007] In one aspect, the present application provides a molecular sieve DNL-13, and the chemical composition of the molecular sieve is

[0008] (H2O) x R2(Si y Al 28-y P 28 O112 ) Formula I;

[0009] In Formula I, R is an organic template agent, and R is selected from 1,5-(N-triethyl)pentane diamine hydroxide;

[0010] x is the number of moles of H2O in each unit cell, x = 0-10.0,

[0011] y is the number of moles of Si in each unit cell, y = 0-2.0,

[0012] The unit cell is Si y Al 28-y P 28 O 112 .

[0013] Optionally, x is selected from any value or a range value between any two of 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

[0014] Optionally, y is selected from any value or a range value between any two of 0, 0.5, 1.0, 1.5, 2.0.

[0015] Optionally, the molecular sieve has a three-dimensional 10*8*8-membered ring pore structure.

[0016] The three-dimensional 10*8*8 of the present application refers to having an 8-membered ring, an 8-membered ring, and a 10-membered ring in the three-dimensional direction, respectively.

[0017] Optionally, the molecular sieve is orthorhombic and belongs to the Pbcm space group.

[0018] Optionally, the unit cell parameters are

[0019] Optionally, the particles of the molecular sieve are rod-shaped.

[0020] Optionally, the molecular sieve has X-ray powder diffraction peaks at least at the following positions:

[0021]

[0022]

[0023] In a second aspect, the present application provides a preparation method of the above-mentioned molecular sieve DNL-13, which comprises the following steps:

[0024] S1: mixing raw materials containing a phosphorus source, an aluminum source, a silicon source, an organic template agent, and a solvent to obtain a reaction gel;

[0025] S2: heating and crystallizing the reaction gel under a closed condition to obtain a molecular sieve raw powder.

[0026] Optionally, in step S1, the molar ratio of the organic template, the phosphorus source, the alcohol solvent, the aluminum source, the silicon source and the water in the reaction gel is aR: bH3PO4: cROH: q Al2O3: m SiO2: nH2O;

[0027] a = 0.3-5.0, the number of moles of the organic template is counted as the number of moles of 1,5-(N-triethyl) pentane diamine hydroxide;

[0028] b = 0.5-2.0, the number of moles of the phosphorus source is counted as the number of moles of H3PO4;

[0029] c = 0-50.0, the number of moles of the alcohol solvent is counted as the number of moles of alcohol ROH;

[0030] q = 0.5-1.2, the number of moles of the aluminum source is counted as the number of moles of Al2O3;

[0031] m = 0-1.0, the number of moles of the silicon source is counted as the number of moles of SiO2;

[0032] n = 5-30, the number of moles of water is counted as the number of moles of H2O.

[0033] Optionally, a is selected from any value or a range between any two values of 0.3, 0.4, 0.5, 0.6, 0.8, 1.0, 1.1, 1.2, 1.4, 1.5, 1.8, 2.1, 2.3, 2.8, 3.2, 3.5, 3.8, 4.0, 4.5, 5.0.

[0034] Optionally, b is selected from any value or a range between any two values of 0.5, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.8, 2.0.

[0035] Optionally, c is independently selected from any value or a range between any two values of 0, 10, 20, 30, 35, 40, 50.

[0036] Optionally, q is independently selected from any value or a range between any two values of 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2.

[0037] Optionally, m is independently selected from any value or a range between any two values of 0, 0.1, 0.15, 0.2, 0.3, 0.5, 0.6, 0.8, 0.9, 1.0.

[0038] Optionally, n is independently selected from any value or a range between any two values of 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 20.0, 30.0.

[0039] Optionally, the phosphorus source is selected from phosphoric acid and / or phosphorus pentoxide; preferably phosphoric acid.

[0040] Optionally, the aluminum source is selected from at least one of pseudoboehmite, aluminum hydroxide and aluminum isopropoxide.

[0041] Optionally, the silicon source is selected from at least one of silica sol, tetraethyl orthosilicate, tetramethoxysilane and white carbon black.

[0042] Optionally, the alcohol solvent is selected from at least one of cyclohexanol, ethylene glycol, diethylene glycol and triethylene glycol; preferably triethylene glycol.

[0043] Optionally, in step S1, the phosphorus source and solvent are mixed, then the aluminum source is added, and then the organic template is added, and the mixture is stirred at 500 rpm to obtain the reaction gel.

[0044] Optionally, in step S2, the temperature of the crystallization is 130-200 DEG C, and the time of the crystallization is 1-15 days.

[0045] Optionally, the crystallization temperature is independently selected from any value or a range value between any two of 130 DEG C, 140 DEG C, 150 DEG C, 160 DEG C, 170 DEG C, 180 DEG C, 190 DEG C and 200 DEG C.

[0046] Optionally, the crystallization time is independently selected from any value or a range value between any two of 1d, 2d, 3d, 4d, 5d, 6d, 7d, 8d, 9d, 10d, 12d, 13d, 14d and 15d.

[0047] Optionally, the as-prepared molecular sieve powder is calcined to remove the template to obtain the molecular sieve DNL-13.

[0048] The calcination temperature is 500-600 DEG C, and the calcination time is 3-5 hours.

[0049] Optionally, in step S2, the post-crystallization product is washed and dried to obtain the as-prepared molecular sieve powder.

[0050] Optionally, the reaction gel is dried in a water bath oven.

[0051] Optionally, the crystallization is performed in a stainless steel high-pressure reaction kettle.

[0052] Optionally, the drying is performed at 90-110 DEG C in air.

[0053] The present application obtains a new structure of phosphosilicate-aluminum molecular sieve DNL-13 with three-dimensional 10*8*8-membered ring channels by designing the reaction ratio of each component and selecting a specific organic template of 1,5-(N-triethyl) pentane diamine hydroxide under reasonable crystallization conditions.

[0054] In a third aspect, the present application provides application of the above-mentioned molecular sieve DNL-13 in adsorption separation.

[0055] In a fourth aspect, the present application provides a water adsorbent, wherein the material of the water adsorbent comprises the above-mentioned molecular sieve DNL-13.

[0056] Optionally, the water adsorption capacity of the adsorbent is greater than or equal to 300 mg / g; that is, at least 300 mg of water can be adsorbed per g of adsorbent.

[0057] Compared with the prior art, the present application has the following beneficial effects:

[0058] 1) The present application synthesizes a new type of framework structure of silicoaluminophosphate molecular sieve; this is of great significance for studying the adsorption of phosphorus aluminum molecular sieve and the catalytic and adsorption properties of superlarge-pore silicoaluminophosphate molecular sieve.

[0059] 2) The preparation method provided by the present application has a simple synthesis process and strong operability.

[0060] 3) The new type of framework structure of silicoaluminophosphate molecular sieve prepared by the present application can be used for adsorption separation and has high water adsorption capacity. BRIEF DESCRIPTION OF DRAWINGS

[0061] Figure 1 is the X-ray powder diffraction spectrum (XRD) of the product obtained in Example 1 of the present application;

[0062] Figure 2 is the scanning electron microscope image (SEM) of the product obtained in Example 1 of the present application;

[0063] Figure 3 is the water adsorption isotherm adsorption curve of DNL-13 in Example 7 of the present application. DETAILED DESCRIPTION

[0064] The present application will be further described below in combination with specific examples. The following description is only a few examples of the present application, and does not limit the present application in any form. Although the present application is disclosed as follows with preferred examples, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above-mentioned disclosed technical contents without departing from the scope of the technical solution of the present application, and the equivalent implementation examples are equivalent to the equivalent implementation examples, which are within the scope of the technical solution.

[0065] Unless otherwise specified, the raw materials in the examples of the present application are purchased through commercial channels and are directly used without any special treatment.

[0066] Unless otherwise specified, the analysis methods in the examples all use the conventional settings of instruments or equipment and conventional analysis methods.

[0067] The analysis method in the embodiments of the present application is as follows:

[0068] The sample phase analysis is analyzed by X-ray powder diffraction (XRD), and the instrument used is X'Pert PRO X-ray diffractometer of PANalytical Company, Netherlands, using Cu target, Kα light source 40KV voltage, 40mA current.

[0069] The sample composition is analyzed by X-ray fluorescence spectroscopy (XRF), and is determined on Magix-601 type X-ray fluorescence spectrometer of Philips Company.

[0070] The sample morphology analysis is analyzed by scanning electron microscope (SEM), and the instrument used is Hitachi SU8020 field emission scanning electron microscope.

[0071] The thermal analysis of the sample is carried out by TA Q-600 thermal analyzer at a temperature rising rate of 10℃ / min from room temperature to 900℃.

[0072] The water vapor adsorption test of the sample is carried out by BSD-VVS multi-station gravimetric gas vapor adsorption instrument of Belsorb Company at P / P0 of 0.8 and temperature of 25℃.

[0073] The cRED data is collected on JEOL 2100Plus transmission electron microscope equipped with EMSIS GmbH camera and ASI Cheetah120 detector.

[0074] Preparation of sample 1 of example 1

[0075] 0.229g of orthophosphoric acid (85%) was added to 4.148g of triethylene glycol (99%) and stirred, then 0.382g of aluminum isopropoxide (98%) was added and stirred until uniform, then 1.16g of 1,5-(N-triethyl)pentane diamine hydroxide (24.0234%) was added, and the mixture was stirred vigorously (500rpm) until uniform, to obtain an initial gel mixture. The mixture was transferred to a water bath oven to dry 0.832g of water. The mixture was moved to a stainless steel high-pressure reaction kettle, and crystallized statically at 200℃ under autogenous pressure for 72 hours. After the crystallization was completed, the solid product was centrifuged, washed, and dried in air at 100℃, to obtain a white powder product.

[0076] The product was confirmed by X-ray powder diffraction to be DNL-13, and was recorded as sample 1.

[0077] The X-ray powder diffraction pattern (XRD) of sample 1 is shown in Figure 1 The scanning electron microscope photograph (SEM) is shown in Figure 2As shown, the particles of sample 1 are rod-like with length size in the range of 50 nm to 500 nm; meanwhile, the morphology of the molecular sieve in the SEM picture is uniform, and the synthesized molecular sieve does not contain other phases, which reflects the high purity of the molecular sieve. XRF analysis and thermal analysis normalization show that the elemental composition of sample 1 is: (P 28 Al 28 O 112 ).2R.4H2O, wherein R is 1,5-(N-triethyl) pentane diamine hydroxide.

[0078] Preparation of sample 2 in Example 2

[0079] 0.227 g of orthophosphoric acid (85%) was added to 4.149 g of triethylene glycol (99%) and stirred, then 0.38 g of aluminum isopropoxide (98%) was added and stirred to a uniform state, and then 1.159 g of 1,5-(N-triethyl) pentane diamine hydroxide (24.0234%) was added and stirred to a uniform state. The initial gel mixture was obtained. The mixture was transferred to a water bath oven to dry 0.422 g of water. The mixture was moved to a stainless steel high-pressure reaction kettle, and static crystallization was carried out at 200°C under autogenous pressure for 72 hours. After the crystallization was completed, the solid product was centrifuged, washed, and dried in air at 100°C to obtain a white powder product.

[0080] The product was confirmed by X-ray powder diffraction to be DNL-13, which is recorded as sample 2.

[0081] The X-ray powder diffraction pattern (XRD) and scanning electron microscope picture (SEM) of sample 2 are similar to those of sample 1.

[0082] Preparation of sample 3 in Example 3

[0083] 0.207 g of orthophosphoric acid (85%) was added to 4.143 g of triethylene glycol (99%) and stirred, then 0.382 g of aluminum isopropoxide (98%) was added and stirred to a uniform state, and then 1.167 g of 1,5-(N-triethyl) pentane diamine hydroxide (24.0234%) was added and stirred to a uniform state. The initial gel mixture was obtained. The mixture was transferred to a water bath oven to dry 0.382 g of water. The mixture was moved to a stainless steel high-pressure reaction kettle, and static crystallization was carried out at 200°C under autogenous pressure for 72 hours. After the crystallization was completed, the solid product was centrifuged, washed, and dried in air at 100°C to obtain a white powder product. The product was confirmed by X-ray powder diffraction to be DNL-13, which is recorded as sample 3.

[0084] The X-ray powder diffraction pattern (XRD) and scanning electron microscope picture (SEM) of sample 3 are similar to those of sample 1.

[0085] Preparation of sample 4 in Example 4

[0086] To 0.384 g aluminum isopropoxide (98%) was added 0.226 g orthophosphoric acid (85%) with stirring until homogeneous, followed by 3.241 g 1,5-(N-triethyl)pentanediamine hydroxide (24.0234%) with vigorous stirring (500 rpm) until homogeneous to give the initial gel mixture. The mixture was transferred to a water bath oven to dry 2.189 g. The mixture was transferred to a stainless steel autoclave and crystallized at 200 °C for 72 hours under autogenous pressure. After crystallization, the solid product was centrifuged, washed, and dried in air at 100 °C to give the white powder product.

[0087] The product was confirmed to be DNL-13 by X-ray powder diffraction, labeled as Sample 4.

[0088] The X-ray powder diffraction pattern (XRD) and scanning electron microscope (SEM) image of Sample 4 were similar to those of Sample 1.

[0089] Example 5 Preparation of Sample 5

[0090] To 4.156 g triethylene glycol was added 0.319 g orthophosphoric acid (85%) with stirring until homogeneous, followed by 0.381 g aluminum isopropoxide (98%) and 0.038 g tetraethyl orthosilicate with stirring until homogeneous, followed by 1.162 g 1,5-(N-triethyl)pentanediamine hydroxide (24.0234%) with vigorous stirring (500 rpm) until homogeneous to give the initial gel mixture. The mixture was transferred to a water bath oven to dry 0.848 g. The mixture was transferred to a stainless steel autoclave and crystallized at 200 °C for 72 hours under autogenous pressure. After crystallization, the solid product was centrifuged, washed, and dried in air at 100 °C to give the white powder product.

[0091] The product was confirmed to be DNL-13 by X-ray powder diffraction, labeled as Sample 5.

[0092] The X-ray powder diffraction pattern (XRD) and scanning electron microscope (SEM) image of Sample 5 were similar to those of Sample 1.

[0093] Example 6 Structure Analysis

[0094] Samples 1-5 were subjected to continuous rotation electron diffraction (cRED) test. The structure analysis results showed that DNL-13 crystallizes in the orthorhombic system with the Pbcm space group, and the unit cell parameters obtained after the final structure refinement were a = 8. 1 A, b = 9. 1 A, c = 17. 1 A, a = 90°, b = 90°, g = 90°. Basic information of the molecular sieve framework can be obtained.

[0095] Example 7 DNL-13 for Adsorptive Separation

[0096] This example is used to illustrate the use of DNL-13 for water adsorbent. But the molecular sieve of the present application is not limited to use for water adsorption.

[0097] The samples 1-5 obtained from examples 1-5 were loaded into the adsorption instrument, pretreated, the pretreatment condition was heating to constant weight at 350℃; then using constant temperature water bath to stabilize the temperature at 30℃, starting to conduct water vapor adsorption test.

[0098] The typical experimental results are shown in Table 1 Figure 3 , Figure 3 The experimental results show that the water vapor adsorption capacity is 317.15mg / g at P / P0 of 0.96; other samples have achieved similar results.

[0099] The above is only a few embodiments of the present application, not any form of the present application to limit, although the present application with the preferred embodiments disclosed as above, however, not to limit the present application, any skilled in the art, without departing from the scope of the present application, using the above disclosed technical content to make some changes or modifications are equivalent to equivalent embodiments, are within the scope of the technical solutions.

Claims

1. A molecular sieve DNL-13, characterized in that, The chemical composition of the molecular sieve is as follows: (H2O) x R2(Si y Al 28-y P 28 O 112 ) Formula I; In Formula I, R is an organic template agent, and R is selected from 1,5-(N-triethyl)pentanediamine hydroxide; x is the number of moles of H2O in each unit cell, x = 0 ~ 10.

0. y is the number of moles of Si in each unit cell, y = 0 ~ 2.

0. The unit cell is Si. y Al 28-y P 28 O 112 .

2. The molecular sieve DNL-13 according to claim 1, characterized in that, The molecular sieve has a three-dimensional 10*8*8 member ring channel structure; The molecular sieve is an orthorhombic crystal system and belongs to the Pbcm space group; The unit cell parameters are a = 13.144 ~ 13.301 Å, b = 17.502 ~ 17.703 Å, and c = 14.668 ~ 14.812 Å. The molecular sieve particles are rod-shaped.

3. The molecular sieve DNL-13 according to claim 1, characterized in that, The molecular sieve exhibits diffraction peaks at least at the following positions in X-ray powder diffraction; 。 4. A method for preparing the molecular sieve DNL-13 according to any one of claims 1 to 3, characterized in that, The preparation method includes the following steps: S1: Raw materials containing phosphorus source, aluminum source, silicon source, organic template agent and solvent are mixed to obtain reaction gel; S2: The reaction gel is heated and crystallized under sealed conditions to obtain molecular sieve powder.

5. The method for preparing molecular sieve DNL-13 according to claim 4, characterized in that, In step S1, the molar ratio of the organic template agent, phosphorus source, alcohol solvent, aluminum source, silicon source and water in the reaction gel is aR:bH3PO4:cROH:qAl2O3:mSiO2:nH2O; a = 0.3 ~ 5.0, the molar number of the organic template agent is calculated as the molar number of 1,5-(N-triethyl)pentanediamine hydroxide; b = 0.5 ~ 2.0, the number of moles of phosphorus source is expressed as the number of moles of H3PO4; c = 0 ~ 50.0, the number of moles of alcohol solvent is expressed as the number of moles of alcohol ROH; q = 0.5 ~ 1.2, where the number of moles of aluminum source is expressed as the number of moles of Al2O3; m = 0 ~ 1.0, the number of moles of silicon source is expressed as the number of moles of SiO2; n = 5 ~ 30, the number of moles of water is expressed as the number of moles of H2O.

6. The method for preparing molecular sieve DNL-13 according to claim 5, characterized in that, The phosphorus source is selected from phosphoric acid and / or phosphorus pentoxide; The aluminum source is selected from at least one of boehmite, aluminum hydroxide and aluminum isopropoxide; The silicon source is selected from at least one of silica sol, tetraethyl orthosilicate, tetramethoxysilane, and silica. The alcohol solvent is selected from at least one of cyclohexanol, ethylene glycol, diethylene glycol, and triethylene glycol.

7. The method for preparing molecular sieve DNL-13 according to claim 4, characterized in that, In step S1, the phosphorus source and solvent are mixed, then an aluminum source is added, followed by an organic template agent, and the mixture is stirred at 500 rpm to obtain the reaction gel. In step S2, the crystallization temperature is 130~200℃, and the crystallization time is 1~15 days.

8. The method for preparing molecular sieve DNL-13 according to claim 4, characterized in that, The molecular sieve powder is calcined to remove the template agent, resulting in the molecular sieve DNL-13. The roasting temperature is 500-600℃, and the roasting time is 3-5 hours.

9. The application of the molecular sieve DNL-13 according to any one of claims 1 to 3 in adsorption separation.

10. A water adsorbent, characterized in that, The material of the water adsorbent includes a molecular sieve DNL-13 as described in any one of claims 1 to 3.

11. A water adsorbent according to claim 10, characterized in that, The water absorption capacity of the adsorbent is greater than or equal to 300 mg / g.

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