A Silicate-1 molecular sieve and its preparation method

Abstract

A Silicate-1 molecular sieve, characterized in that the Silicate-1 molecular sieve contains metal, A HB : A ISO is (15-50): 1, A HB and A ISO respectively represent the peak intensities at the wavenumber of 3400 cm ‑1 and the wavenumber of 3725 cm ‑1 in the infrared spectrum of the Silicate-1 molecular sieve, expressed by the peak area. This molecular sieve has high crystallinity and a high proportion of hydrogen-bonded silanol groups.

Description

Technical Field

[0001] The present invention relates to the field of all-silica molecular sieves, and more specifically, to a Silicate-1 molecular sieve and a preparation method thereof. Background Art

[0002] In 1978, E.M. Flanigen of Union Carbide Corporation in the United States first successfully synthesized Silicalite-1 molecular sieve. Silicalite-1 molecular sieve is an aluminum-free, all-silica molecular sieve with an MFI topological structure and is also the simplest one in the Pentasil family. Its framework only contains silicon atoms and oxygen atoms, and the basic structural unit is SiO 4 tetrahedron. Silicalite-1 molecular sieve has a rich microporous structure and regular and uniform three-dimensional pores. Its crystal structure is the same as that of ZSM-5 molecular sieve, but it has a larger microporous specific surface area and has good thermal stability, hydrophobicity, adsorption and desorption properties.

[0003] Silicalite-1 molecular sieve is currently mainly used in the gas-phase Beckmann rearrangement reaction of cyclohexanone oxime. The hydrogen-bonded silanol groups at the framework defects of Silicalite-1 molecular sieve are the most suitable active centers for the gas-phase rearrangement reaction, while isolated silanol groups are considered the most unfavorable for the reaction. Doping with metals as Lewis acid centers can further improve the catalytic performance of Silicalite-1 molecular sieve. However, the Silicalite-1 molecular sieve synthesized by the prior art has a low crystallinity and a large amount of amorphous structure. After doping with metals, the metal content, the total amount and the species ratio of silanol groups in the Silicalite-1 molecular sieve framework are not easy to control, and post-treatment is required after synthesis to obtain an ideal catalytic effect.

[0004] JP59164617A discloses the synthesis of an MFI-structured silicon molecular sieve, and the raw materials are tetraethyl orthosilicate as the silicon source, tetrapropylammonium hydroxide as the template agent and the base source, respectively.

[0005] US4061724 discloses the synthesis of an all-silica molecular sieve with an MFI structure. The silicon source is one of silica sol, silica gel or fumed silica. The molar ratio of H 2 O to SiO 2 is (150 - 700):(13 - 50); the molar ratio of M 2 O to Q 2 O is 0 - 6.5, and the synthesis is carried out by hydrothermal crystallization at 100 - 250 °C and autogenous pressure for 50 - 150 hours; wherein, M is an alkali metal, Q is a quaternary cation with the molecular formula R 4 X+ , R represents hydrogen or an alkyl group with 2 - 6 carbon atoms, and X is phosphorus or nitrogen.

[0006] A post-treatment process of a Silicalite-1 molecular sieve is mentioned in CN102527424A. The Silicalite-1 molecular sieve catalyst is contacted with a mixed solution of strong acid and hydrofluoric acid to improve its catalytic performance.

[0007] CN106032278A discloses a preparation method of a pure silica molecular sieve Silicalite-1 with a high content of hydrogen-bonded silanol groups. In this method, silica sol is used as the silicon source, tetrapropylammonium bromide is used as the template agent, and sodium hydroxide is added to adjust the pH. The Silicalite-1 molecular sieve after hydrothermal synthesis needs to be treated with an ammonium salt solution to increase the content of hydrogen-bonded silanol groups.

[0008] CN109718828A reports a Silicalite-1 microsphere molecular sieve catalyst containing trace metal ions and its preparation method. After the Silicalite-1 molecular sieve containing trace metal ions is formed into a microsphere catalyst, it needs to be post-treated by contacting with an alkaline buffer solution of a nitrogen-containing compound. Summary of the Invention

[0009] The object of the present invention is to provide a metal-containing Silicate-1 molecular sieve with high crystallinity and a high proportion of hydrogen-bonded silanol groups and to provide a preparation method thereof.

[0010] To achieve the above object, in the first aspect of the present invention, a Silicate-1 molecular sieve is provided, which is characterized in that the Silicate-1 molecular sieve contains metal, and A HB : A ISO is (15 - 50):1, and A HB and A ISO respectively represent the peak intensities at wavenumbers of 3400 cm -1 and 3725 cm -1 in the infrared spectrum of the Silicate-1 molecular sieve, expressed in terms of peak area.

[0011] The peak at wavenumber 3400 cm -1 (the highest value) in the infrared hydroxyl spectrum represents the hydrogen-bonded silanol groups in the Silicate-1 molecular sieve; the peak at wavenumber 3725 cm -1 (the highest value) in the infrared hydroxyl spectrum represents the isolated silanol groups in the Silicate-1 molecular sieve. For the Silicate-1 molecular sieve provided by the present invention, the determination of A HB : A ISO can reflect that it has a higher proportion of hydrogen-bonded silanol groups. Using the Silicate-1 molecular sieve with a higher proportion of hydrogen-bonded silanol groups as a catalyst can effectively reduce the occurrence of various side reactions and help improve the selectivity of the target product. Preferably, A HB : AISO : is (15 - 25):1. The infrared hydroxyl spectrum is obtained by Fourier transform infrared spectroscopy.

[0012] For the Silicate-1 molecular sieve described above, wherein the metal is preferably at least one metal element selected from transition metal elements, Group IIIA and Group IVA elements. Further preferably, the metal is at least one of Group IVB and Group VB elements. Most preferably, the metal is at least one of Ti, Nb, Ta, Ga, La, Ge, Sn and Pb elements.

[0013] For the Silicate-1 molecular sieve described above, wherein the content of the metal, based on the dry weight of the Silicate-1 molecular sieve, is 10 - 5000 ppm, preferably 15 - 4000 ppm, further preferably 50 - 800 ppm, and more preferably 200 - 500 ppm.

[0014] For the Silicate-1 molecular sieve described above, the BET specific surface area is 300 - 500 m 2 / g, preferably 350 - 500 m 2 / g, more preferably 440 - 480 m 2 / g; the external specific surface area is 20 - 100 m 2 / g, preferably 20 - 80 m 2 / g, more preferably 50 - 85 m 2 / g, most preferably 55 - 75 m 2 / g; the particle size is 0.01 - 1 μm, preferably 0.1 - 0.3 μm, more preferably 0.15 - 0.3 μm; the relative crystallinity is 70% - 110%. The preferred relative crystallinity is 80% - 90%.

[0015] In order to achieve the above object, the second aspect of the present invention provides a method for preparing a metal-containing Silicate-1 molecular sieve described in the first aspect of the present invention, which is characterized in that it includes mixing a silicon source, a metal source, a fluorine-containing compound, an organic template agent and water to obtain a colloidal mixture; subjecting the colloidal mixture to hydrothermal crystallization to obtain a crystallization product; washing, filtering, drying and calcining the crystallization product; wherein, the molar ratio of the silicon source: the fluorine-containing compound: the organic template agent: water is 1:(0.01 - 0.50):(0.05 - 0.50):(5 - 100); the weight ratio of the silicon source: the metal source is (100 - 100000):1; the silicon source is calculated as SiO 2 and the metal source is calculated as metal elements.

[0016] Optionally, the silicon source is selected from at least one of silica gel, silica sol, and organosilicate. Preferably, the organosilicate is methyl orthosilicate and / or ethyl orthosilicate.

[0017] Optionally, the metal source is a water-soluble compound or an oil-soluble compound containing metal ions. Preferably, the metal source is at least one of metal-containing inorganic salts, metal alcoholates, and metal esters. For example, the metal source can be TiCl 4 、NbCl 5 、C 10 H 30 O 5 Ta、Ga(NO 3 ) 3 、La(NO 3 ) 3 、GeCl 4 。

[0018] Optionally, the organic template agent is selected from at least one of fatty amine compounds, alkanolamine compounds, and quaternary amine base compounds. The organic template agent is preferably an alkyl quaternary ammonium base compound having 1-4 carbon atoms. More preferably, the alkyl quaternary ammonium base compound is tetraethylammonium hydroxide and / or tetrapropylammonium hydroxide.

[0019] Optionally, the fluorine-containing compound is selected from a water-soluble compound or an oil-soluble compound containing fluorine. Preferably, the fluorine-containing compound is at least one of hydrofluoric acid, ammonium fluoride, boron fluoride, and fluosilicic acid.

[0020] Optionally, the order of mixing the materials is as follows: the metal source is added to the silicon source, and after it is completely dissolved, the organic template agent and water are added. The hydrolysis process is carried out at room temperature for 6-12 h. After complete hydrolysis, the alcohol is removed at a temperature of 50-90 °C for 12-48 h. Finally, the fluorine-containing compound is added and mixed evenly to obtain a colloidal mixture. The above order of mixing the materials helps to obtain a homogeneous crystallization mother liquor and avoid two-phase stratification.

[0021] Optionally, for the hydrothermal crystallization, the conditions are crystallization at a temperature of 80-170 °C for 20-100 h. Preferably, the crystallization is carried out at a temperature of 100-150 °C for 40-60 h. The hydrothermal crystallization can be carried out in a device conventionally selected in the art, such as a hydrothermal reaction kettle.

[0022] Optionally, the drying is carried out at 80-120 °C for 12-36 h; the conditions for the calcination treatment include: the calcination temperature is 400-600 °C and the time is 4-12 h. Preferably, the calcination temperature is 450-550 °C and the time is 6-10 h. The calcination can be carried out in a device conventionally selected in the art, such as a muffle furnace.

[0023] The preparation method provided by the present invention adds a metal and a fluorine-containing compound during the synthesis process, and adds a trace amount of a metal element with the characteristics of a Lewis acid center to allow its metal ions to enter the Silicate-1 molecular sieve framework; adding a fluorine-containing compound can interact with the template agent and the metal ligand respectively, making the defects generated by self-assembly during the crystallization process less and changing the ease of metal entering the framework, and can effectively change the catalytic performance of the all-silica molecular sieve with the MFI topological structure. The metal-containing Silicate-1 molecular sieve provided by the present invention has a special A HB : A ISO proportional relationship, with a high proportion of hydrogen-bonded silanol groups, and the catalytic performance is improved. Description of the Drawings

[0024] Figure 1 It is the X-ray diffraction (XRD) spectrum of the A1 sample in Example 1.

[0025] Figure 2 It is the infrared hydroxyl spectrum of the A1 sample in Example 1.

[0026] Figure 3 It is the infrared hydroxyl spectrum of the D2 sample in Comparative Example 2. Detailed Description of the Invention

[0027] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.

[0028] In the following examples, X-ray fluorescence spectrometry was used to determine the composition of the catalyst. The instrument manufacturer is Rigaku Corporation of Japan, the model is 3031, and the test conditions are tungsten target, excitation voltage 40 kV, and excitation current 50 mA.

[0029] X-ray diffraction spectrometry was used to determine the structure of the catalyst. The instrument manufacturer is PANalytical B.V. of the Netherlands, the model is X′PertPRO, and the test conditions are Cu K radiation, Ni filter, power 40 kV 40 mA, and the scanning range is 2θ = 5° to 35°.

[0030] The BET specific surface area and external specific surface area data of the metal-containing molecular sieve samples in the examples were measured by an ASAP-2020 automatic adsorption instrument produced by Micromeritics of the United States. The test conditions are: N 2 as the adsorbate, the adsorption temperature is -196.2 °C, and it is degassed at a constant temperature of 1.3 Pa and 300 °C for 6 h.

[0031] The infrared hydroxyl group characterization was carried out on a Bruker TENSOR Ⅱ Fourier transform infrared spectrometer. The self-supporting sample wafer was treated at 400 °C for 2 h and then cooled to room temperature for scanning.

[0032] In the following examples, unless otherwise specified, the reagents used were all commercially available reagents.

[0033] In the following examples and comparative examples, unless otherwise specified, the pressure was gauge pressure.

[0034] Example 1

[0035] (1) 0.06 g of C 10 H 30 O 5 Ta was added to 100 g of tetraethyl orthosilicate. After complete dissolution, 120 g of 25 wt% tetrapropylammonium hydroxide and 150 g of water were added and mixed, and stirred at room temperature for 8 h to form a homogeneous colloidal mixture;

[0036] (2) Ethanol was removed at 85 °C (water was continuously added during the process to maintain the material at a certain liquid level) for 20 h, and finally 2.7 g of ammonium fluoride was added to obtain a crystallization mother liquor. The molar ratio of the mixture was SiO 2 ∶NH 4 F∶TPAOH∶H 2 O = 1∶0.15∶0.3∶17, and the mass ratio of SiO 2 to Ta 5+ was 1090∶1;

[0037] (3) The above mixture was transferred into a 2 L autoclave with a polytetrafluoroethylene lining, hydrothermally crystallized at 120 °C for 60 h, washed, filtered, dried at 120 °C for 24 h, and finally calcined at 550 °C for 6 h to obtain molecular sieve A1.

[0038] The specific physical and chemical properties of the A1 sample are listed in Table 1. The relative crystallinity in the table was determined based on the MFI structure molecular sieve described in "Microporous Materials, Vol 22, p637, 1998" as a standard sample with 100% crystallinity.

[0039] The X-ray diffraction (XRD) pattern of the A1 sample is as Figure 1 shown, and the infrared hydroxyl group spectrum (IR) of the molecular sieve is as Figure 2 shown.

[0040] Example 2

[0041] (1) 0.12 g of C 10 H 30 O 5Ta. After complete dissolution, 120 g of 25 wt% tetrapropylammonium hydroxide and 150 g of water were added and mixed, and stirred at room temperature for 8 h to form a homogeneous colloidal mixture;

[0042] (2) Ethanol was removed at 85 °C (water was continuously replenished during the process to maintain the material at a certain liquid level), and the time was 20 h. Finally, 2.7 g of ammonium fluoride was added to obtain a crystallization mother liquor. The molar ratio of the mixture was SiO 2 ∶NH 4 F∶TPAOH∶H 2 O = 1∶0.15∶0.3∶17, and the mass ratio of SiO 2 to Ta 5+ was 545∶1;

[0043] (3) The above mixture was transferred into a 2 L autoclave with a polytetrafluoroethylene liner, hydrothermally crystallized at 120 °C for 60 h, washed, filtered, dried at 120 °C for 24 h, and finally calcined at 550 °C for 6 h to obtain molecular sieve A2.

[0044] The specific physical and chemical properties of the A2 sample are listed in Table 1.

[0045] Example 3

[0046] (1) 0.06 g of C 10 H 30 O 5 Ta was added to 100 g of tetraethyl orthosilicate. After complete dissolution, 120 g of 25 wt% tetrapropylammonium hydroxide and 150 g of water were added and mixed, and stirred at room temperature for 8 h to form a homogeneous colloidal mixture;

[0047] (2) Ethanol was removed at 85 °C (water was continuously replenished during the process to maintain the material at a certain liquid level), and the time was 20 h. Finally, 3.6 g of ammonium fluoride was added to obtain a crystallization mother liquor. The molar ratio of the mixture was SiO 2 ∶NH 4 F∶TPAOH∶H 2 O = 1∶0.2∶0.3∶17, and the mass ratio of SiO 2 to Ta 5+ was 1090∶1;

[0048] (3) The above mixture was transferred into a 2 L autoclave with a polytetrafluoroethylene liner, hydrothermally crystallized at 120 °C for 60 h, washed, filtered, dried at 120 °C for 24 h, and finally calcined at 550 °C for 6 h to obtain molecular sieve A3.

[0049] The specific physical and chemical properties of the A3 sample are listed in Table 1.

[0050] Example 4

[0051] (1) Add 0.12 g of C 10 H 30 O 5 Ta to 100 g of tetraethyl orthosilicate. After complete dissolution, add 120 g of 25 wt% tetrapropylammonium hydroxide and 150 g of water and mix. Stir at room temperature for 8 h to form a homogeneous colloidal mixture;

[0052] (2) Carry out alcohol removal at 85 °C (constantly replenish water during the process to keep the material at a certain liquid level) for 20 h. Finally, add 3.6 g of ammonium fluoride to obtain a crystallization mother liquor. The molar ratio of the mixture is SiO 2 ∶NH 4 F∶TPAOH∶H 2 O = 1∶0.2∶0.3∶17, and the mass ratio of SiO 2 to Ta 5+ is 545∶1;

[0053] (3) Transfer the above mixture into a 2 L autoclave with a polytetrafluoroethylene liner, carry out hydrothermal crystallization at 120 °C for 60 h, wash, filter, dry at 120 °C for 24 h, and finally calcine at 550 °C for 6 h to obtain molecular sieve A4.

[0054] (4) The specific physical and chemical properties of the A4 sample are listed in Table 1.

[0055] Example 5

[0056] (1) Add 0.06 g of C 10 H 30 O 5 Ta to 100 g of tetraethyl orthosilicate. After complete dissolution, add 120 g of 25 wt% tetrapropylammonium hydroxide and 150 g of water and mix. Stir at room temperature for 8 h to form a homogeneous colloidal mixture;

[0057] (2) Carry out alcohol removal at 85 °C (constantly replenish water during the process to keep the material at a certain liquid level) for 20 h. Finally, add 3.65 g of 40 wt% hydrofluoric acid to obtain a crystallization mother liquor. The molar ratio of the mixture is SiO 2 ∶HF∶TPAOH∶H 2 O = 1∶0.15∶0.3∶17, and the mass ratio of SiO 2 to Ta 5+ is 1090∶1;

[0058] (3) Transfer the above mixture into a 2 L autoclave with a polytetrafluoroethylene liner, carry out hydrothermal crystallization at 120 °C for 60 h, wash, filter, dry at 120 °C for 24 h, and finally calcine at 550 °C for 6 h to obtain molecular sieve A5.

[0059] The specific physical and chemical properties of the A5 sample are listed in Table 1.

[0060] Example 6

[0061] (1) Add 0.12 g of C 10 H 30 O 5 Ta to 100 g of tetraethyl orthosilicate. After complete dissolution, add 120 g of 25 wt% tetrapropylammonium hydroxide and 150 g of water and mix. Stir at room temperature for 8 h to form a homogeneous colloidal mixture;

[0062] (2) Carry out alcohol removal at 85 °C (constantly replenish water during the process to maintain the material at a certain liquid level), for 20 h. Finally, add 3.65 g of 40 wt% hydrofluoric acid to obtain the crystallization mother liquor. The molar ratio of the mixture is SiO 2 ∶HF∶TPAOH∶H 2 O = 1∶0.15∶0.3∶17, and the mass ratio of SiO 2 to Ta 5+ is 545∶1;

[0063] (3) Transfer the above mixture into a 2 L autoclave with a polytetrafluoroethylene lining, hydrothermally crystallize at 120 °C for 60 h, wash, filter, dry at 120 °C for 24 h, and finally calcine at 550 °C for 6 h to obtain molecular sieve A6.

[0064] The specific physical and chemical properties of the A6 sample are listed in Table 1.

[0065] Comparative Example 1

[0066] This comparative example illustrates the synthesis of Silicate-1 molecular sieve according to the method of CN103896839A.

[0067] Mix 100 g of tetraethyl orthosilicate, 120 g of 25 wt% tetrapropylammonium hydroxide and 150 g of water, stir at room temperature for 4 h to form a colloidal mixture. The molar ratio of the mixture is SiO 2 ∶TPAOH∶H 2 O = 1∶0.3∶17. Transfer the above mixture into a 2 L autoclave with a polytetrafluoroethylene lining, hydrothermally crystallize at 120 °C for 60 h, wash, filter, dry at 120 °C for 24 h, and finally calcine at 550 °C for 6 h. Add the molecular sieve and the alkaline solution of the nitrogen-containing compound to a pressure autoclave, stir at 80 °C for 1 h, wash, filter and dry to prepare the molecular sieve numbered D1. The specific physical and chemical properties of the D1 sample are listed in Table 1.

[0068] Comparative Example 2

[0069] This comparative example illustrates the molecular sieve prepared without adding fluorine-containing compounds.

[0070] Same as Example 1, the difference from Example 1 is only that: no fluorine-containing compound is added.

[0071] The obtained product was designated as Sample D2. Sample D2 has Figure 1 the characteristics of, indicating that it is Silicate-1 molecular sieve.

[0072] The specific physical and chemical properties of Sample D2 are listed in Table 1.

[0073] The infrared hydroxyl spectrum (IR) of Sample D2 is as Figure 3 shown.

[0074] Table 1

[0075]

[0076] Example 7

[0077] (1) 0.06 g of TiCl was added to 100 g of tetraethyl orthosilicate. After complete dissolution, 120 g of 25 wt% tetrapropylammonium hydroxide and 150 g of water were added and mixed, and stirred at room temperature for 8 h to form a homogeneous colloidal mixture; 4 After complete dissolution, 120 g of 25 wt% tetrapropylammonium hydroxide and 150 g of water were added and mixed, and stirred at room temperature for 8 h to form a homogeneous colloidal mixture;

[0078] (2) Ethanol was removed at a temperature of 85 °C (water was continuously added during the process to maintain the material at a certain liquid level), and the time was 20 h. Finally, 2.7 g of ammonium fluoride was added to obtain a crystallization mother liquor. The molar ratio of the mixture was SiO 2 ∶NH 4 F∶TPAOH∶H 2 O = 1∶0.15∶0.3∶17, and the mass ratio of SiO 2 to Ti 4+ was 1902∶1;

[0079] (3) The above mixture was transferred into a 2 L autoclave with a polytetrafluoroethylene lining, hydrothermally crystallized at 120 °C for 60 h, washed, filtered, dried at 120 °C for 24 h, and finally calcined at 550 °C for 6 h to obtain molecular sieve A7.

[0080] The specific physical and chemical properties of Sample A7 are listed in Table 2.

[0081] Comparative Example 3

[0082] This comparative example illustrates the molecular sieve prepared without adding a fluorine-containing compound.

[0083] Same as Example 7, the difference from Example 7 is only that: no fluorine-containing compound is added. The obtained comparative sample is D3. The specific physical and chemical properties of D3 are listed in Table 2.

[0084] Example 8

[0085] (1) Add 0.06 g of GeCl to 100 g of tetraethyl orthosilicate. 4 After complete dissolution, add 120 g of 25 wt% tetrapropylammonium hydroxide and 150 g of water and mix. Stir at room temperature for 8 h to form a homogeneous colloidal mixture.

[0086] (2) Carry out alcohol removal at 85 °C (continuously add water during the process to maintain the material at a certain liquid level) for 20 h. Finally, add 2.7 g of ammonium fluoride to obtain a crystallization mother liquor. The molar ratio of the mixture is SiO 2 ∶NH 4 F∶TPAOH∶H 2 O = 1∶0.15∶0.3∶17, and the mass ratio of SiO 2 to Ge 4+ is 1419∶1.

[0087] (3) Transfer the above mixture into a 2 L autoclave with a polytetrafluoroethylene lining, carry out hydrothermal crystallization at 120 °C for 60 h, wash, filter, dry at 120 °C for 24 h, and finally calcine at 550 °C for 6 h to obtain molecular sieve A8.

[0088] The specific physical and chemical properties of the A8 sample are listed in Table 2.

[0089] Comparative Example 4

[0090] This comparative example illustrates the molecular sieve prepared without adding a fluorine-containing compound.

[0091] The same as Example 8, the difference from Example 8 is only that: no fluorine-containing compound is added. The obtained comparative sample is D4. The specific physical and chemical properties of D4 are listed in Table 2.

[0092] Example 9

[0093] (1) Add 0.06 g of Ga(NO 3 ) 3 to 100 g of tetraethyl orthosilicate. After complete dissolution, add 120 g of 25 wt% tetrapropylammonium hydroxide and 150 g of water and mix. Stir at room temperature for 8 h to form a homogeneous colloidal mixture.

[0094] (2) Carry out alcohol removal at 85 °C (continuously add water during the process to maintain the material at a certain liquid level) for 20 h. Finally, add 2.7 g of ammonium fluoride to obtain a crystallization mother liquor. The molar ratio of the mixture is SiO 2 ∶NH 4 F∶TPAOH∶H 2 O = 1∶0.15∶0.3∶17, and the mass ratio of SiO 2 to Ga 3+ is 907∶1.

[0095] (3) Transfer the above mixture into a 2 L autoclave with a polytetrafluoroethylene lining, hydrothermally crystallize at 120 °C for 60 h, wash, filter, dry at 120 °C for 24 h, and finally calcine at 550 °C for 6 h to obtain molecular sieve A9.

[0096] The specific physical and chemical properties of the A9 sample are listed in Table 2.

[0097] Comparative Example 5

[0098] This comparative example illustrates the molecular sieve prepared without adding a fluorine-containing compound.

[0099] Same as Example 9, the difference from Example 9 is only that: no fluorine-containing compound is added. The obtained comparative sample is D5. The specific physical and chemical properties of D5 are listed in Table 2.

[0100] Example 10

[0101] (1) Add 0.06 g of La(NO 3 ) 3 .6H 2 O to 100 g of tetraethyl orthosilicate. After complete dissolution, add 120 g of 25 wt% tetrapropylammonium hydroxide and 150 g of water and mix. Stir at room temperature for 8 h to form a homogeneous colloidal mixture;

[0102] (2) Carry out alcohol evaporation at 85 °C (constantly replenish water during the process to keep the material at a certain liquid level) for 20 h, and finally add 2.7 g of ammonium fluoride to obtain a crystallization mother liquor. The molar ratio of the mixture is SiO 2 ∶NH 4 F∶TPAOH∶H 2 O = 1∶0.15∶0.3∶17, and the mass ratio of SiO 2 to La 3+ is 1496∶1;

[0103] (3) Transfer the above mixture into a 2 L autoclave with a polytetrafluoroethylene lining, hydrothermally crystallize at 120 °C for 60 h, wash, filter, dry at 120 °C for 24 h, and finally calcine at 550 °C for 6 h to obtain molecular sieve A10.

[0104] The specific physical and chemical properties of the A10 sample are listed in Table 2.

[0105] Comparative Example 6

[0106] This comparative example illustrates the molecular sieve prepared without adding a fluorine-containing compound.

[0107] Same as Example 10, the difference from Example 10 is only that: no fluorine-containing compound is added. The obtained comparative sample is D6. The specific physical and chemical properties of D6 are listed in Table 2.

[0108] Table 2

[0109]

Claims

1. A Silicate-1 molecular sieve, characterized in that, The Silicate-1 molecular sieve contains metal, A HB : A ISO is (15 - 50):1, A HB and A ISO respectively represent the peak intensities at the wavenumber of 3400 cm -1 and at the wavenumber of 3725 cm -1 in the infrared hydroxyl spectrum of the Silicate-1 molecular sieve, expressed by the peak area; the metal is at least one of Ti, Ta, Ga, La, Ge, and based on the dry basis weight of the Silicate-1 molecular sieve, the content is 10 - 5000 ppm; the Silicate-1 molecular sieve has a BET specific surface area of 300 - 500 m 2 / g, an external specific surface area of 20 - 100 m 2 / g, a particle size of 0.01 - 1 μm, and a relative crystallinity of 70% - 110%.

2. The Silicate-1 molecular sieve according to claim 1, wherein, the content of the metal is 15 - 4000 ppm.

3. The Silicate-1 molecular sieve according to claim 1, wherein, the content of the metal is 50 - 800 ppm.

4. The Silicate-1 molecular sieve according to claim 1, wherein, the content of the metal is 200 - 500 ppm.

5. The Silicate-1 molecular sieve according to claim 1, wherein, The said A HB : A ISO is (15 - 25):

1.

6. The Silicate-1 molecular sieve according to claim 1, wherein, The BET specific surface area is 350 - 500 m 2 / g, the external specific surface area is 50 - 85 m 2 / g, and the particle size is 0.1 - 0.3 μm.

7. The Silicate-1 molecular sieve according to claim 1, wherein, The BET specific surface area is 440 - 480 m 2 / g, the external specific surface area is 20 - 80 m 2 / g, the particle size is 0.15 - 0.3 μm, and the relative crystallinity is 80% - 90%.

8. The Silicate-1 molecular sieve according to claim 7, wherein, The external specific surface area is 50 - 85 m 2 / g.

9. The Silicate-1 molecular sieve according to claim 8, wherein, The external specific surface area is 55 - 75 m 2 / g.

10. A method for preparing the Silicate-1 molecular sieve according to any one of claims 1 - 9, characterized in that, it includes mixing a silicon source, a metal source, a fluorine-containing compound, an organic template agent and water to obtain a colloidal mixture; subjecting the colloidal mixture to hydrothermal crystallization to obtain a crystallization product; The crystallized product is washed, filtered, dried, and calcined; wherein, the molar ratio of silicon source: fluorine-containing compound: organic template: water is 1: (0.01 - 0.50): (0.05 - 0.50): (5 - 100); the weight ratio of the silicon source: metal source is (100 - 100000): 1; the silicon source is calculated as SiO 2 and the metal source is calculated as metal element; the metal in the metal source is at least one of Ti, Ta, Ga, La, and Ge.

11. The preparation method according to claim 10, wherein, the silicon source is at least one selected from silica gel, silica sol and organic silicate esters.

12. The preparation method according to claim 11, wherein, the organic silicate ester is methyl orthosilicate and / or ethyl orthosilicate.

13. The preparation method according to claim 10, wherein, the metal source is a water-soluble compound or an oil-soluble compound containing metal ions.

14. The preparation method according to claim 13, wherein, the metal source is at least one selected from metal-containing inorganic salts, metal alcoholates and metal esters.

15. The preparation method according to claim 14, wherein, The metal source is TiCl 4 , C 10 H 30 O 5 Ta, Ga(NO 3 ) 3 , La(NO 3 ) 3 , GeCl 4 .

16. The preparation method according to claim 10, wherein, the organic template agent is selected from at least one of aliphatic amine compounds, alkanolamine compounds and quaternary amine base compounds.

17. The preparation method according to claim 16, wherein, the organic template agent is an alkyl quaternary ammonium base compound having 1 - 4 carbon atoms.

18. The preparation method according to claim 17, wherein, the alkyl quaternary ammonium base compound is tetraethylammonium hydroxide and / or tetrapropylammonium hydroxide.

19. The preparation method according to claim 10, wherein, the fluorine-containing compound is selected from a water-soluble compound or an oil-soluble compound containing fluorine.

20. The preparation method according to claim 19, wherein, the fluorine-containing compound is at least one of hydrofluoric acid, ammonium fluoride, boron fluoride and fluosilicic acid.

21. The preparation method according to claim 10, wherein, The order of material mixing is as follows: Add the metal source to the silicon source. After it is completely dissolved, add the organic template agent and water, and carry out the hydrolysis process at room temperature for 6 - 12 h. After complete hydrolysis, carry out alcohol removal at a temperature of 50 - 90 °C for 12 - 48 h. Finally, add the fluorine-containing compound and mix evenly to obtain a colloidal mixture.

22. According to the preparation method described in claim 10, wherein, for the hydrothermal crystallization, the conditions are crystallization at a temperature of 80 - 170 °C for 20 - 100 h.

23. The Silicate-1 molecular sieve obtained by the preparation method of any one of claims 10 - 22.

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