Method for preparing MOR type titanium silicalite molecular sieve by supergravity and application of MOR type titanium silicalite molecular sieve

Abstract

The invention discloses a method for preparing an MOR type titanium silicalite molecular sieve through supergravity and application, and the method comprises the following steps: 1) mixing a silicon source and water to form a mixture A, mixing an inorganic base, an aluminum source and organic amine R to form an initial mixture B, and simultaneously introducing the initial mixture A and the initial mixture B into a supergravity machine; (2) transferring the mixture C in the step (1) into a stirring kettle, and crystallizing; 3) filtering, separating, washing, drying and calcining the solid product to obtain a mordenite MOR molecular sieve; 4) mixing the MOR molecular sieve with an NH4Cl solution, stirring, filtering, washing, drying, and calcining to obtain an H-MOR molecular sieve; 5) mixing the H-MOR molecular sieve with a nitric acid solution, stirring, filtering, washing, drying and calcining to obtain a dealuminated MOR molecular sieve; and 6) supplementing titanium to the dealuminated MOR molecular sieve, and calcining to obtain the Ti-MOR molecular sieve. According to the method, the dealumination efficiency and the titanium content in the titanium silicalite molecular sieve can be remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of molecular sieve preparation, and specifically relates to a method for preparing a MOR-type titanium silicon molecular sieve under ultra-gravity conditions and its application. The titanium silicon molecular sieve has a MOR topological structure. Background Art

[0002] Titanium silicate molecular sieves are heteroatom molecular sieves formed by partially replacing the Si atoms in the all-silicon molecular sieve framework with the transition metal Ti. In 1983, Taramasso introduced Ti atoms into the ZSM-5 framework to prepare the TS-1 catalyst (see US Patent 4,410,501), marking the birth of titanium silicate molecular sieves.

[0003] Titanium silicate molecular sieves exhibit unique catalytic efficiency and selectivity in the selective oxidation reaction of organic matter using hydrogen peroxide as an oxidant, becoming an important catalyst in liquid-phase oxidation reactions and opening a new chapter in the field of zeolite molecular sieves.

[0004] Since then, scientists have developed microporous titanium silicalite molecular sieves with varying topologies, including TS-2, Ti-ZSM-48, Ti-Beta, Ti-MOR, and Ti-MWW. Ti-MOR molecular sieve, due to its larger twelve-membered ring pores, exhibits higher activity than TS-1 molecular sieve in the hydroxylation of macromolecular aromatic hydrocarbons. Compared to TS-1 and Ti-MWW molecular sieves, Ti-MOR molecular sieve exhibits superior catalytic performance in the ammoxidation of aldehydes and ketones, such as acetaldehyde, acetone, butanone, and cyclohexanone.

[0005] The preparation method of Ti-MOR molecular sieve adopts the isomorphous substitution secondary synthesis method, that is, starting from Al-MOR, aluminum is first removed by acid washing, and then TiCl4 vapor is used in a high-temperature inert atmosphere for gas-solid isomorphous replacement.

[0006] For example, Chinese patent application CN115417420A discloses a method for preparing Ti-MOR molecular sieve, which specifically comprises the following steps: at room temperature, mixing white carbon black, boric acid, sodium aluminate, sodium hydroxide and water to obtain a gel precursor for synthesizing the molecular sieve; placing the gel precursor into a hydrothermal crystallization reactor, heating it to 160-180°C, and crystallizing it for 72-120 hours; after the reaction is completed, performing solid-liquid separation, washing the resulting solid with dilute hydrochloric acid, and drying it to obtain a borosilicate aluminum molecular sieve having a MOR structure; after acid washing to remove boron and aluminum, the borosilicate aluminum molecular sieve having the MOR structure reacts with ammonium fluoride and amorphous titanium dioxide under ultraviolet light to prepare Ti-MOR molecular sieve. The molecular sieve obtained by this method for preparing Ti-MOR molecular sieve has good catalytic activity, avoids the use of organic amines and high-temperature vapor-phase titanium addition reaction in the preparation process, and the fluorine-containing waste liquid generated in the preparation process can be recycled, with little pollution to the environment.

[0007] The synthesis system for MOR molecular sieves is typically a sodium-containing hydrogel alkaline system, consisting of a gel phase and a liquid phase, and exhibiting a certain degree of viscosity. This results in low dispersion efficiency of large aluminosilicate aggregates during the premixing stage, causing the aggregates to aggregate and settle, resulting in increased molecular sieve particle size and increased agglomeration. The morphology of the molecular sieve has a significant impact on the pickling process for aluminum removal and titanium addition. Larger crystal size makes aluminum removal more difficult, and also makes it more difficult to implant titanium in the framework's four-matching position. Summary of the Invention

[0008] The first technical problem to be solved by the present invention is to provide a method for preparing MOR-type titanium silicon molecular sieves under high gravity. This method adopts a secondary synthesis method, that is, first using high gravity to enhance the premixing and dispersion of the gel phase to prepare the MOR molecular sieve, and then preparing the titanium silicon molecular sieve by dealumination and titanium supplementation. The significant advantage of this method is that it can significantly improve the mixed mass transfer of the gel phase, so that the crystal nuclei are evenly dispersed, thereby reducing the particle size of the molecular sieve and reducing the agglomeration of the molecular sieve, which can significantly improve the dealumination efficiency and the titanium content in the titanium silicon molecular sieve.

[0009] The second technical problem to be solved by the present invention is to provide an application of the titanium silicon molecular sieve prepared by the above preparation method in the selective oxidation reaction of organic matter using hydrogen peroxide as an oxidant.

[0010] In order to solve the above-mentioned first technical problem, the technical solution adopted by the present invention is as follows :

[0011] A method for preparing MOR type titanium silicon molecular sieve under high gravity, comprising the following steps:

[0012] 1) mixing a silicon source and water to form an initial mixture A; then mixing an inorganic base, an aluminum source, and an organic amine R to form an initial mixture B; then simultaneously introducing the initial mixture A and the initial mixture B into a hypergravity machine and mixing them uniformly to form a mixture C;

[0013] 2) transferring the mixture C in step 1) into a stirred tank for crystallization;

[0014] 3) After the crystallization is completed, the solid product is filtered and separated, washed with deionized water until neutral, dried, and calcined to obtain mordenite MOR molecular sieve;

[0015] 4) Mixing the mordenite MOR molecular sieve with a 0.1-1M NH4Cl solution, stirring to perform ion exchange, washing and drying, and repeating 1-4 times; calcining the ion-exchanged MOR molecular sieve in air to obtain H-MOR molecular sieve;

[0016] 5) Mixing the H-MOR molecular sieve with a 3-6M nitric acid solution, stirring and refluxing, filtering, washing, drying and calcining to obtain a dealuminated MOR molecular sieve;

[0017] 6) The dealuminated MOR molecular sieve is placed in a tubular furnace and purged with nitrogen. TiCl4 vapor is replaced with titanium by gas-solid isomorphous replacement at high temperature. After the titanium replacement is completed, nitrogen is continued to be purged to remove excess TiCl4 vapor. The molecular sieve is then washed with deionized water, dried, and calcined to obtain the Ti-MOR molecular sieve.

[0018] Preferably, in step 1), the silicon source is selected from at least one of silica sol, water glass, white carbon black, tetramethyl silicate, and tetraethyl silicate.

[0019] Preferably, in step 1), the aluminum source is selected from at least one of aluminum sol, aluminum sulfate, aluminum hydroxide, aluminum chloride, aluminum nitrate, aluminum isopropoxide, sodium metaaluminate, and sodium aluminate.

[0020] Preferably, in step 1), the inorganic base is selected from sodium hydroxide or potassium hydroxide.

[0021] Preferably, in step 1), the organic amine is selected from at least one of trimethylamine, triethylamine, N,N-dimethylethylenediamine, n-propylamine, di-n-propylamine, isopropylamine, tetramethylammonium hydroxide, tetramethylammonium bromide, tetramethylammonium chloride, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrapropylammonium bromide.

[0022] Preferably, in step 1), the silicon source is calculated as SiO2, the inorganic base is calculated as M2O, and the aluminum source is calculated as Al2O3, and the molar ratio in the mixture C is:

[0023] SiO2:Al2O3=1:0.02-0.1,

[0024] SiO2:H2O=1:15-30,

[0025] SiO2:M2O=1:0.04-0.12,

[0026] SiO2:R=1:0.1-1.

[0027] In step 1), the rotation speed of the hypergravity machine is 400 to 3000 rpm.

[0028] Preferably, in step 2), the crystallization temperature is 120-200° C., the time is 12-40 h; and the rotation speed of the stirring tank is 100-1000 rpm.

[0029] Preferably, in step 3), the drying temperature is 100° C. and the time is 12 h; the calcination temperature is 400-700° C. and the time is 6 h.

[0030] Preferably, in step 4), the solid-to-liquid (mass) ratio of the MOR molecular sieve to the 0.1-1M NH4Cl solution is 20-40.

[0031] Preferably, in step 4), the ion exchange time is 2-6 hours; the calcination temperature is 400-700° C., and the time is 2-6 hours.

[0032] Preferably, in step 5), the solid-to-liquid (mass) ratio of the H-MOR molecular sieve to the 3-6M nitric acid solution is 10-50.

[0033] Preferably, in step 5), the stirring and reflux time is 5-25 hours, preferably 6-12 hours; the calcination temperature is 400-700° C., and the time is 2-6 hours.

[0034] Preferably, in step 6), the temperature of the titanium supplementation is 200-600° C., and the time is 10-120 min.

[0035] Preferably, in step 6), the drying temperature is 100° C. and the drying time is 12 h.

[0036] Preferably, in step 6), the calcination temperature is 400-700° C. and the calcination time is 2-6 hours.

[0037] In order to solve the above second technical problem, the technical solution adopted by the present invention is as follows:

[0038] The titanium silicon molecular sieve prepared by the preparation method is used in the selective oxidation reaction of organic matter using hydrogen peroxide as an oxidant.

[0039] Any range described in the present invention includes the end value and any numerical value between the end values ​​and any sub-range formed by the end value or any numerical value between the end values.

[0040] Unless otherwise specified, all raw materials in the present invention can be purchased commercially, and the equipment used in the present invention can adopt conventional equipment in the relevant field or refer to the existing technology in the relevant field.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] (1) The product particle size is significantly reduced, with an average particle size of 110-300nm, and agglomeration is reduced;

[0043] (2) It can significantly improve the dealumination efficiency of the product;

[0044] (3) It can significantly increase the titanium content in titanium silicate molecular sieve. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0046] Figure 1 This is an SEM image of the titanium silicate sample synthesized in Example 7;

[0047] Figure 2 This is the SEM image of the titanium silicate sample synthesized in Comparative Example 1. DETAILED DESCRIPTION

[0048] In order to explain the present invention more clearly, the present invention is further described below in conjunction with preferred embodiments. Those skilled in the art should understand that the following specific description is illustrative rather than restrictive and should not be used to limit the scope of protection of the present invention.

[0049] As one aspect of the present invention, a method for preparing a MOR type titanium silicon molecular sieve under high gravity comprises the following steps:

[0050] 1) mixing a silicon source and water to form an initial mixture A; then mixing an inorganic base, an aluminum source, and an organic amine R to form an initial mixture B; then simultaneously introducing the initial mixture A and the initial mixture B into a hypergravity machine and mixing them uniformly to form a mixture C;

[0051] 2) transferring the mixture C in step 1) into a stirred tank for crystallization;

[0052] 3) After the crystallization is completed, the solid product is filtered and separated, washed with deionized water until neutral, dried, and calcined to obtain mordenite MOR molecular sieve;

[0053] 4) Mixing the mordenite MOR molecular sieve with a 0.1-1M NH4Cl solution, stirring to perform ion exchange, washing and drying, and repeating 1-4 times; calcining the ion-exchanged MOR molecular sieve in air to obtain H-MOR molecular sieve;

[0054] 5) Mixing the H-MOR molecular sieve with a 3-6M nitric acid solution, stirring and refluxing, filtering, washing, drying and calcining to obtain a dealuminated MOR molecular sieve;

[0055] 6) The dealuminated MOR molecular sieve is placed in a tubular furnace and purged with nitrogen. TiCl4 vapor is replaced with titanium by gas-solid isomorphous replacement at high temperature. After the titanium replacement is completed, nitrogen is continued to be purged to remove excess TiCl4 vapor. The molecular sieve is then washed with deionized water, dried, and calcined to obtain the Ti-MOR molecular sieve.

[0056] According to some embodiments of the present invention, in step 1), the silicon source is selected from at least one of silica sol, water glass, white carbon black, tetramethyl silicate, and tetraethyl silicate.

[0057] According to some embodiments of the present invention, in step 1), the aluminum source is selected from at least one of aluminum sol, aluminum sulfate, aluminum hydroxide, aluminum chloride, aluminum nitrate, aluminum isopropoxide, sodium metaaluminate, and sodium aluminate.

[0058] According to certain embodiments of the present invention, in step 1), the inorganic base is selected from sodium hydroxide or potassium hydroxide.

[0059] According to some embodiments of the present invention, in step 1), the organic amine is selected from at least one of trimethylamine, triethylamine, N,N-dimethylethylenediamine, n-propylamine, di-n-propylamine, isopropylamine, tetramethylammonium hydroxide, tetramethylammonium bromide, tetramethylammonium chloride, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrapropylammonium bromide.

[0060] According to certain embodiments of the present invention, in step 1), the silicon source is calculated as SiO2, the inorganic base is calculated as M2O, and the aluminum source is calculated as Al2O3, and the molar ratio in the mixture C is:

[0061] SiO2:Al2O3=1:0.02-0.1,

[0062] SiO2:H2O=1:15-30,

[0063] SiO2:M2O=1:0.04-0.12,

[0064] SiO2:R=1:0.1-1.

[0065] According to some embodiments of the present invention, the rotation speed of the hypergravity machine is 400-3000 rpm.

[0066] According to certain embodiments of the present invention, in step 2), the crystallization temperature is 120-200° C., the time is 12-40 h; and the rotation speed of the stirring tank is 100-1000 rpm.

[0067] According to certain embodiments of the present invention, in step 3), the drying temperature is 100° C. and the time is 12 h; the calcination temperature is 400-700° C. and the time is 6 h.

[0068] According to certain embodiments of the present invention, in step 4), the solid-to-liquid (mass) ratio of the MOR molecular sieve to the 0.1-1M NH4Cl solution is 20-40.

[0069] According to certain embodiments of the present invention, in step 4), the ion exchange time is 2-6 hours; the calcination temperature is 400-700° C., and the time is 2-6 hours.

[0070] According to certain embodiments of the present invention, in step 5), the solid-to-liquid (mass) ratio of the H-MOR molecular sieve to the 3-6M nitric acid solution is 10-50.

[0071] According to certain embodiments of the present invention, in step 5), the stirring and reflux time is 5-25 hours, preferably 6-12 hours; the calcination temperature is 400-700° C., and the time is 2-6 hours.

[0072] According to some embodiments of the present invention, in step 6), the temperature of the titanium supplementation is 200-600° C., and the time is 10-120 min.

[0073] According to some embodiments of the present invention, in step 6), the drying temperature is 100° C. and the drying time is 12 hours.

[0074] According to certain embodiments of the present invention, in step 6), the calcination temperature is 400-700° C. and the calcination time is 2-6 hours.

[0075] As another aspect of the present invention, the titanium silicon molecular sieve prepared by the above preparation method is used in the selective oxidation reaction of organic matter using hydrogen peroxide as an oxidant.

[0076] Example 1

[0077] A method for preparing MOR type titanium silicon molecular sieve under high gravity, comprising the following steps:

[0078] 1) Preparation of silicon-containing mixed solution and aluminum-containing mixed solution

[0079] The silica sol and water were mixed in a molar ratio of SiO2:H2O=1:8 to prepare a silicon-containing mixed solution, and then NaOH, aluminum sol and tetraethylammonium hydroxide were mixed in a molar ratio of Na2O:Al2O3:TEAOH=8:1:5 to prepare an aluminum-containing mixed solution;

[0080] 2) Hypergravity premixing

[0081] The silicon-containing mixed liquid and the aluminum-containing mixed liquid are simultaneously introduced into a hypergravity machine at a speed of 1000-3000 rpm to form a mixture with the following molar ratio: SiO2:Al2O3:Na2O:TEAOH:H2O=1:0.033:0.12:0.15:30. After the premixing is completed, the silicon-aluminum mixture gel is introduced into the hypergravity machine and circulated for 5-15 minutes.

[0082] 3) Hydrothermal crystallization

[0083] The mixture was transferred into a stirred tank and crystallized at 180°C under autogenous pressure for 30 hours at a rotation speed of 1000 rpm, and then filtered, washed, dried and calcined to obtain Na-type mercerized molecular sieve;

[0084] 4) Ion exchange

[0085] Na-type mercerized molecular sieves were mixed with 1M NH4Cl solution at a solid-liquid ratio of 1:40, stirred for 6 hours, filtered, washed, and dried, and the ion-exchanged MOR molecular sieves were calcined in air at a temperature of 550°C for 4 hours to obtain H-MOR molecular sieves.

[0086] 5) Pickling and dealuminization

[0087] The H-MOR molecular sieve was mixed with 6M nitric acid solution at a solid-liquid ratio of 1:40, stirred and refluxed for 10 hours, and then filtered, washed, dried and calcined to obtain the dealuminated MOR molecular sieve;

[0088] 6) Vapor phase titanium filling

[0089] The dealuminated MOR molecular sieve is placed in a tubular furnace, and TiCl4 vapor is purged with nitrogen to supplement titanium through gas-solid isomorphous replacement at high temperature. The temperature is 400°C and the time is 120 minutes. After the titanium supplement is completed, nitrogen is continued to be purged to remove excess TiCl4 vapor; after washing, drying and calcining, the Ti-MOR molecular sieve can be obtained.

[0090] The data of the initial silicon-to-aluminum ratio, silicon-to-aluminum ratio after dealumination, and final silicon-to-titanium ratio of the molecular sieve during the preparation process of Example 1 are shown in Table 1 below, and the testing method is ICP-OES.

[0091] Figure 1 This is the SEM image of the titanium silicate sample synthesized in Example 1.

[0092] After testing, the average particle size of the obtained Ti-MOR molecular sieve is 110-200 nm.

[0093] Example 2

[0094] Repeat Example 1, except that:

[0095] In step 1), the NaOH, aluminum sol and tetraethylammonium hydroxide are mixed in a molar ratio of Na2O:Al2O3:TEAOH=4.8:1:3 to prepare an aluminum-containing mixed solution;

[0096] In step 2), the SiO2:Al2O3:Na2O:TEAOH:H2O=1:0.05:0.12:0.15:30;

[0097] The data of the initial silicon-to-aluminum ratio, silicon-to-aluminum ratio after dealumination, and final silicon-to-titanium ratio of the molecular sieve during the preparation process of Example 2 are shown in Table 1 below, and the testing method is ICP-OES.

[0098] Example 3

[0099] Repeat Example 1, except that:

[0100] In step 1), the NaOH, aluminum sol and tetraethylammonium hydroxide are mixed in a molar ratio of Na2O:Al2O3:TEAOH=3:1:1.8 to prepare an aluminum-containing mixed solution;

[0101] In step 2), the SiO2:Al2O3:Na2O:TEAOH:H2O=1:0.084:0.12:0.15:30;

[0102] The data of the initial silicon-to-aluminum ratio, silicon-to-aluminum ratio after dealumination, and final silicon-to-titanium ratio of the molecular sieve during the preparation process of Example 3 are shown in Table 1 below, and the testing method is ICP-OES.

[0103] Example 4

[0104] Repeat Example 3, except that:

[0105] In step 2), the SiO2:Al2O3:Na2O:TEAOH:H2O=1:0.084:0.12:0.15:10;

[0106] The data of the initial silicon-to-aluminum ratio, silicon-to-aluminum ratio after dealumination, and final silicon-to-titanium ratio of the molecular sieve during the preparation process of this Example 4 are shown in Table 1 below, and the testing method is ICP-OES.

[0107] Example 5

[0108] Repeat Example 3, except that:

[0109] In step 2), the SiO2:Al2O3:Na2O:TEAOH:H2O=1:0.084:0.12:0.15:20;

[0110] The data of the initial silicon-to-aluminum ratio, silicon-to-aluminum ratio after dealumination, and final silicon-to-titanium ratio of the molecular sieve during the preparation process of this Example 5 are shown in Table 1 below, and the testing method is ICP-OES.

[0111] Example 6

[0112] Repeat Example 3, except that:

[0113] In step 1), the silica sol and water are mixed in a molar ratio of SiO2:H2O=1:8 to prepare a silicon-containing mixed solution, and then NaOH, sodium metaaluminate and tetraethylammonium hydroxide are mixed in a molar ratio of Na2O:Al2O3:TEAOH=3:1:1.8 to prepare an aluminum-containing mixed solution;

[0114] The data of the initial silicon-to-aluminum ratio, silicon-to-aluminum ratio after dealumination, and final silicon-to-titanium ratio of the molecular sieve during the preparation process of Example 6 are shown in Table 1 below, and the testing method is ICP-OES.

[0115] Example 7

[0116] Repeat Example 3, except that:

[0117] In step 1), the silica sol and water are mixed in a molar ratio of SiO2:H2O=1:8 to prepare a silicon-containing mixed solution, and then NaOH, aluminum sulfate and tetraethylammonium hydroxide are mixed in a molar ratio of Na2O:Al2O3:TEAOH=3:1:1.8 to prepare an aluminum-containing mixed solution;

[0118] The data of the initial silicon-to-aluminum ratio, silicon-to-aluminum ratio after dealumination, and final silicon-to-titanium ratio of the molecular sieve during the preparation process of this Example 7 are shown in Table 1 below, and the testing method is ICP-OES.

[0119] Example 8

[0120] Repeat Example 3, except that:

[0121] In step 5), the stirring reflux time is 15 hours.

[0122] The data of the initial silicon-to-aluminum ratio, silicon-to-aluminum ratio after dealumination, and final silicon-to-titanium ratio of the molecular sieve during the preparation process of Example 8 are shown in Table 1 below, and the testing method is ICP-OES.

[0123] Example 9

[0124] Repeat Example 3, except that:

[0125] In step 5), the stirring reflux time is 20 hours.

[0126] The data of the initial silicon-to-aluminum ratio, silicon-to-aluminum ratio after dealumination, and final silicon-to-titanium ratio of the molecular sieve during the preparation process of Example 9 are shown in Table 1 below, and the testing method is ICP-OES.

[0127] Example 10

[0128] Example 9 was repeated except that:

[0129] In step 5), the H-MOR molecular sieve is mixed with a 6M nitric acid solution at a solid-liquid ratio of 1:20.

[0130] The data of the initial silicon-to-aluminum ratio, silicon-to-aluminum ratio after dealumination, and final silicon-to-titanium ratio of the molecular sieve during the preparation process of Example 10 are shown in Table 1 below, and the testing method is ICP-OES.

[0131] Example 11

[0132] Example 9 was repeated except that:

[0133] In step 5), the H-MOR molecular sieve is mixed with a 6M nitric acid solution at a solid-liquid ratio of 1:30.

[0134] The data of the initial silicon-to-aluminum ratio, the silicon-to-aluminum ratio after dealumination, and the final silicon-to-titanium ratio of the molecular sieve during the preparation process of this Example 11 are shown in Table 1 below, and the testing method is ICP-OES.

[0135] Example 12

[0136] The Ti-MOR molecular sieve prepared in Example 1 was applied to the selective oxidation reaction of organic matter using hydrogen peroxide as an oxidant. The specific steps are as follows:

[0137] Butanone, molecular sieves, and tert-butanol were added to the reactor in a mass ratio of 8:2:3, and the solid-liquid mixture was heated to 65°C; ammonia water and hydrogen peroxide were slowly added to the reactor in a molar ratio of butanone:NH3:H2O2=1:1:1 over 70 minutes. After the addition was completed, the reaction was continued for 30 minutes with a stirring speed of 500 rpm.

[0138] The concentration of the reaction solution was detected by gas chromatography.

[0139] In this Example 12, it was measured that the conversion rate of butanone of the Ti-MOR molecular sieve prepared in Example 1 was 99.2%, and the selectivity for butanone oxime was 99.5%.

[0140] Comparative Example 1

[0141] Example 9 was repeated except that:

[0142] In step 2), the silicon-containing mixed solution and the aluminum-containing mixed solution are simultaneously introduced into the stirring tank instead of into the supergravity machine, with a rotation speed of 400-600 rpm.

[0143] The data of the initial silicon-to-aluminum ratio, the silicon-to-aluminum ratio after dealumination, and the final silicon-to-titanium ratio of the molecular sieve during the preparation process of this comparative example 1 are shown in Table 1 below, and the testing method is ICP-OES.

[0144] Figure 2 This is the SEM image of the titanium silicate sample synthesized in Comparative Example 1.

[0145] Comparative Example 2

[0146] Example 7 was repeated except that:

[0147] In step 2), the silicon-containing mixed solution and the aluminum-containing mixed solution are simultaneously introduced into the stirring tank instead of into the supergravity machine, with a rotation speed of 400-600 rpm.

[0148] Table 1 below shows the initial silicon-to-aluminum ratio, silicon-to-aluminum ratio after dealumination, and final silicon-to-titanium ratio of the molecular sieves during the preparation process in each embodiment and comparative example:

[0149] Table 1

[0150] Si / Al Si / Al after dealumination Si / Ti Example 1 15.2 91.5 106.4 Example 2 10.1 85.6 98.0 Example 3 6.5 80.2 89.4 Example 4 6.9 31.9 143.5 Example 5 7.2 65.4 125.9 Example 6 7.1 79.9 90.8 Example 7 6.4 80.2 89.4 Example 8 6.5 102.3 86.9 Example 9 6.5 189.1 83.4 Example 10 6.5 115.7 86.9 Example 11 6.5 145.9 85.7 Comparative Example 1 6.5 69.8 123.4 Comparative Example 2 6.4 46.7 134.2

[0151] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications based on the above description are possible. It is not possible to enumerate all embodiments here. Any obvious variations or modifications arising from the technical solution of the present invention remain within the scope of protection of the present invention.

Claims

1. A method for preparing MOR type titanium silicon molecular sieve under high gravity, characterized in that: The steps include: 1) mixing a silicon source and water to form an initial mixture A; then mixing an inorganic base, an aluminum source, and an organic amine R to form an initial mixture B; then simultaneously introducing the initial mixture A and the initial mixture B into a hypergravity machine and mixing them uniformly to form a mixture C; 2) transferring the mixture C in step 1) into a stirred tank for crystallization; 3) After the crystallization is completed, the solid product is filtered and separated, washed with deionized water until neutral, dried, and calcined to obtain mordenite MOR molecular sieve; 4) Mixing the mordenite MOR molecular sieve with a 0.1-1M NH4Cl solution, stirring to perform ion exchange, washing and drying, and repeating 1-4 times; calcining the ion-exchanged MOR molecular sieve in air to obtain H-MOR molecular sieve; 5) Mixing the H-MOR molecular sieve with a 3-6M nitric acid solution, stirring and refluxing, filtering, washing, drying and calcining to obtain a dealuminated MOR molecular sieve; 6) The dealuminated MOR molecular sieve is placed in a tubular furnace and purged with nitrogen. TiCl4 vapor is replaced with titanium by gas-solid isomorphous replacement at high temperature. After the titanium replacement is completed, nitrogen is continued to be purged to remove excess TiCl4 vapor. The molecular sieve is then washed with deionized water, dried, and calcined to obtain the Ti-MOR molecular sieve.

2. The method for preparing MOR type titanium silicon molecular sieve under high gravity according to claim 1, characterized in that: In step 1), the silicon source is selected from at least one of silica sol, water glass, white carbon black, tetramethyl silicate, and tetraethyl silicate; Preferably, in step 1), the aluminum source is selected from at least one of aluminum sol, aluminum sulfate, aluminum hydroxide, aluminum chloride, aluminum nitrate, aluminum isopropoxide, sodium metaaluminate, and sodium aluminate; Preferably, in step 1), the inorganic base is selected from sodium hydroxide or potassium hydroxide; Preferably, in step 1), the organic amine is selected from at least one of trimethylamine, triethylamine, N,N-dimethylethylenediamine, n-propylamine, di-n-propylamine, isopropylamine, tetramethylammonium hydroxide, tetramethylammonium bromide, tetramethylammonium chloride, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrapropylammonium bromide.

3. The method for preparing MOR type titanium silicon molecular sieve under high gravity according to claim 1, characterized in that: In step 1), the silicon source is calculated as SiO2, the inorganic base is calculated as M2O, and the aluminum source is calculated as Al2O3. The molar ratio in the mixture C is: SiO2:Al2O3=1:0.02-0.1, SiO2:H2O=1:15-30, SiO2:M2O=1:0.04-0.12, SiO2:R=1:0.1-1.

4. The method for preparing MOR type titanium silicon molecular sieve under high gravity according to claim 1, characterized in that: In step 1), the rotation speed of the hypergravity machine is 400 to 3000 rpm.

5. The method for preparing MOR type titanium silicon molecular sieve under high gravity according to claim 1, characterized in that: In step 2), the crystallization temperature is 120-200° C., the time is 12-48 hours, and the rotation speed of the stirring tank is 100-1000 rpm.

6. The method for preparing MOR type titanium silicon molecular sieve under high gravity according to claim 1, characterized in that: In step 3), the drying temperature is 100° C. and the time is 12 h; the calcination temperature is 400-700° C. and the time is 6 h.

7. The method for preparing MOR type titanium silicon molecular sieve under high gravity according to claim 1, characterized in that: In step 4), the MOR molecular sieve and 0.1-1M NH4Cl solution are mixed at a solid-to-liquid ratio of 20-40; Preferably, in step 4), the ion exchange time is 2-6 hours; the calcination temperature is 400-700° C., and the time is 2-6 hours.

8. The method for preparing MOR type titanium silicon molecular sieve under high gravity according to claim 1, characterized in that: In step 5), the H-MOR molecular sieve and 3-6M nitric acid solution are mixed at a solid-to-liquid ratio of 10-50; Preferably, in step 5), the stirring and reflux time is 5-25 hours, preferably 6-12 hours; the calcination temperature is 400-700° C., and the time is 2-6 hours.

9. The method for preparing MOR type titanium silicon molecular sieve under high gravity according to claim 1, characterized in that: In step 6), the temperature of the titanium supplementation is 200-600°C and the time is 10-120 minutes; Preferably, in step 6), the drying temperature is 100° C. and the drying time is 12 h; Preferably, in step 6), the calcination temperature is 400-700° C. and the calcination time is 2-6 hours.

10. Use of the titanium silicate prepared by the method according to any one of claims 1 to 9 in the selective oxidation reaction of organic matter using hydrogen peroxide as an oxidant.

Images