An olefin epoxide titanium silica catalyst, its preparation method and application

Abstract

This invention discloses an olefin epoxidized titanium silicate catalyst, its preparation method, and its applications. The UV-Raman spectrum of the olefin epoxidized titanium silicate catalyst of this invention is at 364±6 cm⁻¹. ‑1 500±6cm ‑1 and 1102±6cm ‑1 A spectral peak appears at 1102±6 cm⁻¹. ‑1 The intensity of the spectral peak is 364±6 cm⁻¹. ‑1 The peak intensity is 1 to 10 times that of the catalyst in this invention. The catalyst used in the olefin epoxidation reaction exhibits high olefin conversion, high epoxide selectivity, and good catalytic stability.

Description

Technical Field

[0001] This invention belongs to the field of petrochemical catalysts, specifically relating to an olefin epoxide titanium silicate catalyst, its preparation method, and its application. Background Technology

[0002] Epoxides are important organic chemical raw materials, mainly used in the production of glycols, polyesters, polyether polyols, etc. Their main varieties include ethylene oxide, propylene oxide, 1,2-epoxypentane, and 1,2-epoxyhexane. Currently, epoxides are primarily produced through the selective oxidation of olefins. For example, ethylene oxide is obtained by epoxidation of ethylene with air in the presence of a silver catalyst; the industrial production methods for 1,2-epoxypentane and 1,2-epoxyhexane are the organic peroxyacid oxidation method using 1-pentene and 1-hexene, which suffers from severe equipment corrosion, high risk, and poor atom economy; the industrial production routes for propylene oxide mainly include the chlorohydrin method, co-oxidation methods with co-products (PO / SM method and PO / MTBE method or PO / TBA method), the hydrogen peroxide method without co-products (HPPO method), and the cumene hydroperoxide method (CHP method). The chlorohydrin process has been gradually phased out due to severe environmental pollution. The co-oxidation process with co-products overcomes the pollution and corrosion disadvantages of the chlorohydrin process, but it has a long process, large investment, and large output of co-products. The market demand has a great influence on this process. The CHP and HPPO processes without co-products have become the development direction of propylene oxide production technology due to their low pollution and no co-product generation. The core of these two technologies is the propylene epoxidation catalyst used in them.

[0003] Titanium-silicon materials exhibit excellent catalytic activity for the selective oxidation of hydrocarbons and can be used to catalyze the epoxidation of olefins to prepare epoxides. US4410501 first disclosed a method for synthesizing TS-1 molecular sieve. First, a titanium-containing silica gel solution is prepared using an aqueous solution of tetrapropylammonium hydroxide, an organotitanate, and an organosilicon ester as raw materials, followed by direct hydrothermal crystallization. This invention of a novel catalytic material lays the foundation for research on efficient hydrocarbon oxidation reactions and the development of environmentally friendly processes. However, because TS-1 is a microporous molecular sieve with an MFI structure, its application is limited to the HPPO process, which uses hydrogen peroxide (H2O2) as an oxidant to selectively oxidize propylene to prepare propylene oxide. When organic peroxides, such as cumene hydroperoxide (CHP) and ethylbenzene hydroperoxide (EBHP), are used as oxidants, TS-1 exhibits almost no catalytic activity.

[0004] US3923843 and US4367342 disclose EBHP using titanium-containing amorphous silica as a catalyst to selectively oxidize propylene to propylene oxide. However, due to the small specific surface area and pore volume of the amorphous silica support, the titanium loading is not high, and the catalyst surface is highly hydrophilic, resulting in low catalytic activity. The reaction product, propylene oxide, easily undergoes ring-opening hydrolysis on its surface and further polymerizes to form a larger molecular weight polymer that adheres to the catalyst surface. This not only affects the selectivity of the catalyst for propylene oxide but also easily causes catalyst deactivation and reduces catalyst stability. Therefore, this type of catalyst is unsuitable for long-cycle and low-material-consumption high-efficiency propylene catalytic epoxidation reaction systems.

[0005] CN1500004A and CN1248579A disclose catalysts with structures similar to Ti-MCM-41, using CHP or EBHP as oxidants, to selectively oxidize propylene to propylene oxide. However, the quaternary ammonium salt templates used in the synthesis process are expensive, and the required crystallization process is lengthy, resulting in low catalyst production efficiency and high manufacturing costs. Furthermore, the catalysts suffer from unsatisfactory activity and hydrophobicity, leading to numerous byproducts and poor stability, significantly impacting the economic viability of industrial propylene oxide production.

[0006] CN107224993B describes a method for preparing a SiO2-Ti-MeO-SiO2 catalyst with high propylene oxide selectivity. This involves loading TiCl4 onto a metal salt-containing silica support via chemical vapor deposition, followed by steam washing, surface SiO2 coating, and silanization. CN107715868B describes a method where a silicon source is pre-hydrolyzed, then a titanium source is added to form a sol. The sol is atomized and sprayed into liquid ammonia to form a pore, followed by pore expansion, drying, calcination, and silanization to obtain a Ti-SiO2 composite oxide catalyst. Both of these methods involve lengthy preparation processes and require highly corrosive and environmentally hazardous titanium sources (TiCl4 or liquid ammonia), making them unsuitable for industrial production.

[0007] In summary, existing olefin epoxide titanium silica catalysts have poor catalytic performance, complex preparation processes, and require highly corrosive and environmentally harmful reagents. Therefore, there is a need to develop olefin epoxide titanium silica catalysts with good catalytic performance and simple and environmentally friendly preparation methods. Summary of the Invention

[0008] One of the technical problems this invention aims to solve is addressing the shortcomings of existing olefin epoxide titanium silicate catalysts, such as poor catalytic performance, complex preparation processes, and the use of highly corrosive and environmentally harmful reagents. This invention provides an olefin epoxide titanium silicate catalyst with superior catalytic performance.

[0009] The second technical problem this invention aims to solve is to address the current lack of a simple and green method for preparing olefin epoxide titanium silica catalysts with good catalytic performance, and to provide a method for preparing olefin epoxide titanium silica catalysts. This preparation method is simple and environmentally friendly.

[0010] The third technical problem to be solved by this invention is to provide an application of a titanium-silicon epoxide catalyst for olefin epoxidation in the olefin epoxidation reaction. The catalyst of this invention features high olefin conversion, high epoxide selectivity, and good catalytic stability.

[0011] To address one of the aforementioned technical problems, the first aspect of this invention provides an olefin epoxide titanium silicate catalyst, the ultraviolet Raman spectrum of which is within 364±6 cm⁻¹. -1 500±6cm -1 and 1102±6cm -1 A spectral peak appears at 1102±6 cm⁻¹. -1 The intensity of the spectral peak is 364±6 cm⁻¹. -1 The intensity of the spectral peak is 1.0 to 10.0 times, preferably 3.0 to 8.0 times.

[0012] According to the present invention, the titanium-silicon catalyst further comprises silicon, titanium, and carbon, and the overall silicon-titanium molar ratio is 20-200, preferably 25-100.

[0013] According to the present invention, the titanium-silicon catalyst has a surface silicon-to-titanium molar ratio of 10 to 100, preferably 12 to 50; and a surface silicon-to-carbon molar ratio of 0.5 to 6.0, preferably 1.0 to 5.0.

[0014] According to the present invention, the toluene adsorption capacity of the titanium-silicon catalyst, measured under the conditions of 20°C, P / P0 = 0.1 and an adsorption time of 2 h, is 150–450 mg / g molecular sieve, preferably 250–400 mg / g molecular sieve.

[0015] According to the present invention, the mechanical strength of the titanium-silicon catalyst is further 40-90 N / cm, preferably 50-80 N / cm.

[0016] To address the second technical problem mentioned above, a second aspect of the present invention provides a method for preparing an olefin epoxide titanium silica catalyst, comprising the following steps:

[0017] (1) Mix silicon source A, titanium source, organic alkali and water, and perform hydrothermal treatment to obtain titanium-containing binder;

[0018] (2) The silicon source B, the titanium-containing binder and the pore-forming agent from step (1) are kneaded together and calcined to obtain the catalyst precursor.

[0019] (3) The catalyst precursor from step (2) is contacted with a mixture of organosilanes and organic amines to obtain the titanium-silicon catalyst.

[0020] According to the present invention, further, the proportion of each material in step (1), in molar ratio, is as follows: silicon source A is SiO2: titanium source is TiO2: organic base: water = 1:x:y:z; wherein x = 0.01~0.5, y = 0.05~0.5, z = 5~25, preferably: x = 0.05~0.3, y = 0.1~0.4, z = 12~20.

[0021] According to the present invention, further, in step (1), the silicon source A is selected from at least one of tetraethyl orthosilicate, fumed silica, and silica sol; the titanium source is selected from at least one of tetrabutyl titanate, tetraisopropyl titanate, titanium tetrachloride, hexafluorotitanic acid, and ammonium hexafluorotitanic acid; the organic base is selected from at least one of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, dimethyl diethylammonium hydroxide, dimethyl diisopropylammonium hydroxide, piperidine, and hexamethyleneimine. Preferably, the silicon source A is selected from at least one of tetraethyl orthosilicate and silica sol; the titanium source is selected from at least one of tetrabutyl titanate, tetraisopropyl titanate, and hexafluorotitanic acid; and the organic base is selected from at least one of tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, dimethyl diethylammonium hydroxide, and dimethyl diisopropylammonium hydroxide.

[0022] According to the present invention, the hydrothermal treatment in step (1) is further performed in stages. The first stage hydrothermal treatment conditions are: 60-119°C for 1-24 hours, preferably 80-100°C for 2-20 hours; the second stage hydrothermal treatment conditions are: 120-180°C for 0.5-6 hours, preferably 130-170°C for 2-5 hours; and / or, the temperature of the second stage hydrothermal treatment is 10-120°C higher than the temperature of the first stage hydrothermal treatment, preferably 20-100°C.

[0023] According to the present invention, further, the proportions of each material in step (2), specifically the mass ratio of silicon source B (calculated as SiO2), titanium-containing binder in step (1), and pore-forming agent, are 1:0.2-1.8:0.01-0.3, preferably 1:0.3-1.5:0.05-0.2. During the kneading and molding process, a certain amount of water can be appropriately volatilized or added to ensure that the obtained catalyst achieves good mechanical strength.

[0024] According to the present invention, the silicon source B in step (2) is selected from at least one of fumed silica or silicon powder; the pore-forming agent is selected from at least one of guar gum powder, cellulose, chitosan, lignin, starch, polyethylene glycol, triblock copolymer P123, and F127.

[0025] According to the present invention, the calcination conditions in step (2) are further as follows: calcination at 450-650°C in an oxygen-containing atmosphere for 4-12 hours. Drying is performed before calcination at 60-120°C for 1-24 hours.

[0026] According to the present invention, further, in step (3), the mass ratio of the catalyst precursor to the organosilane and the organic amine is 1:0.01-0.5:0.01-0.5, preferably 1:0.05-0.40:0.05-0.40.

[0027] According to the present invention, the organosilane in step (3) is further selected from at least one of hexamethyldisilazane, triethylchlorosilane, chloromethyl(dimethyl)methoxysilane, octadecyldimethylmethoxysilane, ethoxytrimethylsilane, triallylethoxysilane, dimethyldiethoxysilane, and methylphenyldimethoxysilane, preferably at least one of hexamethyldisilazane, triethylchlorosilane, and chloromethyl(dimethyl)methoxysilane; the organoamine is selected from at least one of methylamine, ethylamine, ethylenediamine, n-propylamine, n-butylamine, diethylamine, triethylamine, and hexamethylenediamine, preferably at least one of methylamine, ethylamine, ethylenediamine, n-propylamine, n-butylamine, and diethylamine.

[0028] According to the present invention, the treatment conditions in step (3) are further as follows: treatment at 80-180°C for 0.5-24 hours, preferably at 100-160°C for 1-12 hours. After treatment, the sample is washed with an organic solvent and dried, wherein the drying conditions are 60-120°C for 1-24 hours.

[0029] The present invention also provides an olefin epoxide titanium silicon catalyst prepared by the above method.

[0030] According to the present invention, the titanium-silicon catalyst prepared by the method further exhibits an ultraviolet Raman spectrum at 364±6 cm⁻¹. -1 500±6cm -1 and 1102±6cm -1 A spectral peak appears at 1102±6 cm⁻¹. -1 The intensity of the spectral peak is 364±6 cm⁻¹. -1 The intensity of the spectral peak is 1.0 to 10.0 times, preferably 3.0 to 8.0 times.

[0031] According to the present invention, the titanium-silicon catalyst prepared by the method further comprises silicon, titanium and carbon, and the overall silicon-titanium molar ratio is 20 to 200, preferably 25 to 100.

[0032] According to the present invention, the titanium-silicon catalyst prepared by the method has a surface silicon-to-titanium molar ratio of 10 to 100, preferably 12 to 50; and a surface silicon-to-carbon molar ratio of 0.5 to 6.0, preferably 1.0 to 5.0.

[0033] According to the present invention, the titanium-silicon catalyst prepared by the method further exhibits a toluene adsorption capacity of 150–450 mg / g molecular sieve, preferably 250–400 mg / g molecular sieve, measured under the conditions of 20°C, P / P0 = 0.1, and an adsorption time of 2 h.

[0034] According to the present invention, the titanium-silicon catalyst prepared by the method further has a mechanical strength of 40-90 N / cm, preferably 50-80 N / cm.

[0035] To address the third technical problem mentioned above, this invention provides an application of the aforementioned titanium-silicon olefin epoxidation catalyst in the olefin epoxidation reaction.

[0036] According to the present invention, the application step further includes: mixing an olefin, a hydrogen peroxide alkylbenzene solution, and a solvent as a feed liquid, and reacting it with the catalyst. The reaction apparatus is a fixed-bed reactor.

[0037] According to the present invention, further, the olefin is a liquefied olefin; the olefin includes at least one selected from propylene, allyl chloride, butene, pentene, cyclopentene, hexene, and cyclohexene; the hydrogen peroxide alkylbenzene includes at least one selected from cumene hydrogen peroxide and ethylbenzene hydrogen peroxide; the mass fraction of hydrogen peroxide alkylbenzene in the hydrogen peroxide alkylbenzene solution is 30% to 90%; the solvent is selected from at least one selected from cumene, ethylbenzene, toluene, and benzene.

[0038] According to the present invention, further, in the feed liquid, the molar ratio of olefin to alkylbenzene peroxide is 1:0.1 to 0.5; and the olefin accounts for 5% to 50% of the mass fraction of the feed liquid.

[0039] According to the present invention, the flow rate of the catalyst per unit mass of the feed liquid is further 3 to 30 mL·g. cat. -1 ·h -1 The reaction temperature is 40–120°C, and the reaction pressure is 0.1–4 MPa.

[0040] Compared with the prior art, the present invention has the following advantages:

[0041] 1. In this invention, the ultraviolet Raman spectrum of the olefin epoxide titanium silica catalyst is at 364±6 cm⁻¹. -1 500±6cm -1 and 1102±6cm -1A spectral peak appears at 1102±6 cm⁻¹. -1 The intensity of the spectral peak is 364±6 cm⁻¹. -1 The peak intensity is 1 to 10 times that of the spectral peak. 364±6cm -1 The spectral peaks are attributed to a partially crystallized SiO2 matrix, 500±6 cm⁻¹ -1 and 1102±6cm -1 The spectral peaks belong to a four-coordinated titanium species in the framework, which is the catalytic active center for olefin epoxidation. High intensity peaks are observed at 500±6 cm⁻¹. -1 and 1102±6cm -1 The presence of spectral peaks indicates the presence of a large number of well-formed titanium species. The toluene adsorption capacity of the titanium silicate catalyst for olefin epoxidation, measured at 20℃, P / P0 = 0.1, and an adsorption time of 2 h, was 150–450 mg / g molecular sieve, indicating that the catalyst possesses good hydrophobicity and large pore volume, which facilitates diffusion and mass transfer. The titanium silicate catalyst, when used in olefin epoxidation reactions, exhibits high olefin conversion, high epoxide selectivity, and good catalytic stability.

[0042] 2. In this invention, the catalyst preparation method involves first mixing silicon source A, titanium source, organic base, and water, followed by hydrothermal treatment to obtain a titanium-containing binder. Then, silicon source B, the titanium-containing binder, and a pore-forming agent are kneaded together and calcined to obtain a catalyst precursor. Finally, the catalyst precursor is contacted with a mixture of organosilane and organic amine to obtain the titanium-silicon catalyst. This invention's preparation method, by preparing a titanium-containing binder, kneading it with silicon source B and a pore-forming agent, and then calcining it, can simply and effectively introduce four-coordinate titanium species into the prepared titanium-silicon catalyst. Further treatment with organosilane and organic amine can reduce silanol groups, improve the state of the four-coordinate titanium species, increase the catalyst's hydrophobicity, and thus improve catalytic performance. The titanium-silicon catalyst prepared by this invention exhibits excellent catalytic activity, selectivity, and stability in olefin epoxidation reactions.

[0043] 3. The catalyst of this invention exhibits excellent catalytic performance in olefin epoxidation reactions, with high olefin conversion, high epoxide selectivity, and good catalytic stability, demonstrating promising application prospects. Attached Figure Description

[0044] Figure 1 The UV-Raman spectrum of the olefin epoxide titanium silica catalyst prepared in [Example 1] is shown below.

[0045] Figure 2 The UV-Raman spectrum of the olefin epoxide titanium silica catalyst prepared in [Comparative Example 1] is shown below.

[0046] Figure 3 The UV-Raman spectrum of the olefin epoxide titanium silica catalyst prepared in [Comparative Example 2] is shown below.

[0047] Figure 4 The UV-Raman spectrum of the olefin epoxide titanium silica catalyst prepared in [Comparative Example 3] is shown below.

[0048] Figure 5 The UV-Raman spectrum of the olefin epoxide titanium silica catalyst prepared in [Comparative Example 4] is shown below.

[0049] Figure 6 The UV-Raman spectrum of the olefin epoxide titanium silica catalyst prepared in [Comparative Example 5] is shown below.

[0050] Figure 7 The image shows the UV-Raman spectrum of the olefin epoxide titanium silica catalyst prepared in [Comparative Example 6]. Detailed Implementation

[0051] The technical solution of the present invention will be further illustrated below with reference to the embodiments, but it is not limited to the following embodiments.

[0052] In this invention, unless otherwise expressly stated, percentages and whole parts are by mass. Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprising of," etc., shall be understood to include the stated steps or components, but not to exclude other steps or other components.

[0053] In this invention, including the following examples and comparative examples, the titanium species state and the overall silicon-to-titanium molar ratio of the titanium-silicon catalyst are determined by ultraviolet Raman spectroscopy and inductively coupled atomic emission spectroscopy, respectively; the surface silicon-to-titanium molar ratio and the surface silicon-to-carbon molar ratio of the titanium-silicon catalyst are determined by X-ray photoelectron spectroscopy; and the toluene adsorption capacity and mechanical strength of the titanium-silicon catalyst are determined by benzene adsorption and strength tester, respectively.

[0054] In this invention, the ultraviolet Raman spectroscopy testing method is as follows: A domestically produced UV Raman-100 ultraviolet Raman spectrometer is used for testing, with an excitation wavelength of 244 nm, a laser power of 5.0 mW illuminating the sample, and a spectral resolution of 4 cm⁻¹. -1 The intensity of a spectral peak is obtained by subtracting the baseline background from the peak value.

[0055] In this invention, the inductively coupled atomic emission spectroscopy (ICAES) method is as follows: the overall silicon-titanium molar ratio in the sample is analyzed using a Varian-2000 analyzer, and the sample is dissolved in hydrofluoric acid solution before the test.

[0056] In this invention, the X-ray photoelectron spectroscopy test method is as follows: the silicon, titanium, and carbon species and signal intensity on the surface of the titanium-silicon catalyst are measured using an AXIS ULTRA DLD X-ray photoelectron spectrometer, and the surface silicon-titanium molar ratio and surface silicon-carbon molar ratio are calculated accordingly.

[0057] In this invention, the benzene adsorption test method is as follows: the test is performed using a Hiden intelligent gravimetric analyzer. Before the test, the sample is pretreated in a vacuum at 353K for 10 hours.

[0058] In this invention, the mechanical strength testing method is as follows: the DL-2 type particle strength tester is used to test the size of the catalyst in the direction of force application, and then the external force required to compress the catalyst into powder is measured. The mechanical strength of the catalyst is obtained by dividing the external force by the size.

[0059] In this invention, the reaction liquid after flowing through the titanium-silicon catalyst bed is collected, the concentration of cumene hydroperoxide in the reaction liquid is determined by iodometric titration, and the residual rate and conversion rate of cumene hydroperoxide are calculated.

[0060]

[0061] Cumene peroxide conversion rate % = 1 - Cumene peroxide residue rate %.

[0062] In this invention, gas chromatography is used to analyze the product composition and calculate the selectivity of the main product epoxide and the byproducts diol and alcohol ether, as well as the ratio of main to byproducts.

[0063]

[0064]

[0065] In this invention, timing begins when the two plunger pumps are turned on and ends when the residual rate of cumene hydroperoxide in the reaction solution reaches 2%. The corresponding running time is the catalyst stabilization time.

[0066]

Example 1

[0067] (1) First, mix the corresponding amounts of water, tetrapropylammonium hydroxide, tetrabutyl titanate and tetraethyl orthosilicate uniformly in a molar ratio of SiO2:TiO2:tetrapropylammonium hydroxide:water of 1:0.2:0.4:15. Then, treat at 80°C for 8 hours and then at 150°C for 2 hours to obtain titanium-containing binder.

[0068] (2) Next, fumed silica, titanium-containing binder and guar gum powder are mixed evenly in a mass ratio of 1:1:0.1, stirred and kneaded for 4 hours to obtain a solid mixture with a certain viscosity. After mechanical extrusion molding, it is dried at 100°C for 8 hours and then calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor.

[0069] (3) A cylindrical catalyst precursor, hexamethyldisilazane and ethylenediamine were mixed in a mass ratio of 1:0.2:0.1 and treated at 120°C for 8 hours. After washing with ethanol and drying at 100°C for 8 hours, an olefin epoxide titanium silicon catalyst was obtained, denoted as S1.

[0070] The UV-Raman spectrum of catalyst S1 is as follows: Figure 1 As shown, 364cm was observed. -1 500cm -1 1102cm -1 Spectral peak, 1102 cm⁻¹ -1 The peak intensity is 364 cm⁻¹ -1 6.0 times the peak intensity, 364 cm⁻¹ -1 The spectral peaks are attributed to a SiO2 matrix with a certain degree of crystallization, 500 cm⁻¹ -1 1102cm -1 The spectral peaks belong to a four-coordinate titanium species in the framework, which is the catalytic active center for olefin epoxidation; the overall silicon-titanium molar ratio of the catalyst S1 is 30, the surface silicon-titanium molar ratio is 15, and the surface silicon-carbon molar ratio is 3.0; the toluene adsorption capacity of the catalyst S1 measured at 20℃, P / P0 = 0.1, and an adsorption time of 2h is 300 mg / g; the mechanical strength of the catalyst S1 is 60 N / cm.

[0071]

Example 2

[0072] (1) First, mix the corresponding amounts of water, tetrapropylammonium hydroxide, tetrabutyl titanate and tetraethyl orthosilicate uniformly in a molar ratio of SiO2:TiO2:tetrapropylammonium hydroxide:water of 1:0.02:0.1:10. Then, treat at 80°C for 8 hours and then at 150°C for 2 hours to obtain a titanium-containing binder.

[0073] (2) Next, fumed silica, titanium-containing binder and guar gum powder are mixed evenly in a mass ratio of 1:1:0.1, stirred and kneaded for 4 hours to obtain a solid mixture with a certain viscosity. After mechanical extrusion molding, it is dried at 100°C for 8 hours and then calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor.

[0074] (3) The cylindrical catalyst precursor, hexamethyldisilazane and ethylenediamine were mixed in a mass ratio of 1:0.2:0.1 and treated at 120°C for 8 hours. After washing with ethanol and drying at 100°C for 8 hours, the olefin epoxide silicon catalyst was obtained and denoted as S2.

[0075] The UV-Raman spectrum of catalyst S2 and Figure 1 Similarly, 370cm was observed. -1 494cm -1 1108cm -1 Spectral peak, 1108 cm⁻¹ -1 The peak intensity is 370 cm⁻¹ -1 The peak intensity is 1.0 times that of the catalyst S2; the overall silicon-titanium molar ratio of the catalyst S2 is 200, the surface silicon-titanium molar ratio is 100, and the surface silicon-carbon molar ratio is 2.5; the toluene adsorption capacity of the catalyst S2 measured at 20℃, P / P0=0.1 and an adsorption time of 2h is 325mg / g; the mechanical strength of the catalyst S2 is 54N / cm.

[0076]

Example 3

[0077] (1) First, mix the corresponding amounts of water, piperidine, titanium tetrachloride and fumed silica in a molar ratio of SiO2:TiO2:piperidine:water of 1:0.5:0.4:25. Then, treat the mixture at 80°C for 8 hours and at 150°C for 2 hours to obtain a titanium-containing binder.

[0078] (2) Next, fumed silica, titanium-containing binder and guar gum powder are mixed evenly in a mass ratio of 1:1:0.1, stirred and kneaded for 4 hours to obtain a solid mixture with a certain viscosity. After mechanical extrusion molding, it is dried at 100°C for 8 hours and then calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor.

[0079] (3) The cylindrical catalyst precursor, hexamethyldisilazane and ethylenediamine were mixed in a mass ratio of 1:0.2:0.1 and treated at 120°C for 8 hours. After washing with ethanol and drying at 100°C for 8 hours, the olefin epoxide silicon catalyst was obtained and denoted as S3.

[0080] The UV-Raman spectrum of catalyst S3 and Figure 1 Similarly, 358cm was observed. -1 506cm -1 1096cm -1 Spectral peak, 1096 cm⁻¹ -1 The peak intensity is 358 cm⁻¹ -1The peak intensity is 10.0 times that of the catalyst S3; the overall silicon-titanium molar ratio of the catalyst S3 is 20, the surface silicon-titanium molar ratio is 10, and the surface silicon-carbon molar ratio is 3.6; the toluene adsorption capacity of the catalyst S3 measured at 20℃, P / P0=0.1 and an adsorption time of 2h is 272mg / g; the mechanical strength of the catalyst S3 is 80N / cm.

[0081]

Example 4

[0082] (1) First, mix the corresponding amounts of water, tetrabutylammonium hydroxide, hexafluorotitanic acid and silica sol evenly with a molar ratio of SiO2:TiO2:tetrabutylammonium hydroxide:water of 1:0.25:0.4:15. Then, treat at 80°C for 8 hours and then at 150°C for 2 hours to obtain titanium-containing binder.

[0083] (2) Next, fumed silica, titanium-containing binder and guar gum powder are mixed evenly in a mass ratio of 1:1:0.1, stirred and kneaded for 4 hours to obtain a solid mixture with a certain viscosity. After mechanical extrusion molding, it is dried at 100°C for 8 hours and then calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor.

[0084] (3) The cylindrical catalyst precursor, hexamethyldisilazane and ethylenediamine were mixed in a mass ratio of 1:0.2:0.1 and treated at 120°C for 8 hours. After washing with ethanol and drying at 100°C for 8 hours, the olefin epoxide titanium silicon catalyst was obtained and denoted as S4.

[0085] The UV-Raman spectrum of catalyst S4 and Figure 1 Similarly, 366cm was observed. -1 498cm -1 1103cm -1 Spectral peak, 1103 cm⁻¹ -1 The peak intensity is 366 cm⁻¹ -1 The peak intensity is 7.6 times that of the catalyst S4; the overall silicon-titanium molar ratio of the catalyst S4 is 28, the surface silicon-titanium molar ratio is 14, and the surface silicon-carbon molar ratio is 3.8; the toluene adsorption capacity of the catalyst S4 measured at 20℃, P / P0=0.1 and an adsorption time of 2h is 250mg / g; the mechanical strength of the catalyst S4 is 76N / cm.

[0086]

Example 5

[0087] (1) First, mix the corresponding amounts of water, tetrapropylammonium hydroxide, tetrabutyl titanate and tetraethyl orthosilicate uniformly in a molar ratio of SiO2:TiO2:tetrapropylammonium hydroxide:water of 1:0.2:0.4:15. Then, treat at 60°C for 24 hours and then at 180°C for 1 hour to obtain titanium-containing binder.

[0088] (2) Next, fumed silica, titanium-containing binder and guar gum powder are mixed evenly in a mass ratio of 1:1:0.1, stirred and kneaded for 4 hours to obtain a solid mixture with a certain viscosity. After mechanical extrusion molding, it is dried at 100°C for 8 hours and then calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor.

[0089] (3) A cylindrical catalyst precursor, hexamethyldisilazane and ethylenediamine were mixed in a mass ratio of 1:0.2:0.1 and treated at 120°C for 8 hours. After washing with ethanol and drying at 100°C for 8 hours, an olefin epoxide titanium silicon catalyst was obtained, denoted as S5.

[0090] The UV-Raman spectrum of catalyst S5 and Figure 1 Similarly, 362cm was observed. -1 502cm -1 1101cm -1 Spectral peak, 1101 cm⁻¹ -1 The peak intensity is 362 cm⁻¹ -1 The peak intensity is 5.4 times that of the catalyst S5; the overall silicon-titanium molar ratio of the catalyst S5 is 36, the surface silicon-titanium molar ratio is 17, and the surface silicon-carbon molar ratio is 2.5; the toluene adsorption capacity of the catalyst S5 measured at 20℃, P / P0=0.1 and an adsorption time of 2h is 320mg / g; the mechanical strength of the catalyst S5 is 64N / cm.

[0091]

Example 6

[0092] (1) First, mix the corresponding amounts of water, tetrapropylammonium hydroxide, tetrabutyl titanate and tetraethyl orthosilicate uniformly in a molar ratio of SiO2:TiO2:tetrapropylammonium hydroxide:water of 1:0.2:0.4:15. Then, treat at 110°C for 1 hour and then at 120°C for 6 hours to obtain titanium-containing binder.

[0093] (2) Next, fumed silica, titanium-containing binder and guar gum powder are mixed evenly in a mass ratio of 1:1:0.1, stirred and kneaded for 4 hours to obtain a solid mixture with a certain viscosity. After mechanical extrusion molding, it is dried at 100°C for 8 hours and then calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor.

[0094] (3) The cylindrical catalyst precursor, hexamethyldisilazane and ethylenediamine were mixed in a mass ratio of 1:0.2:0.1 and treated at 120°C for 8 hours. After washing with ethanol and drying at 100°C for 8 hours, the olefin epoxide titanium silicon catalyst was obtained and denoted as S6.

[0095] The UV-Raman spectrum of catalyst S6 and Figure 1 Similarly, 367cm was observed. -1 496cm -11106cm -1 Spectral peak, 1106 cm⁻¹ -1 The peak intensity is 367 cm⁻¹ -1 The peak intensity is 4.7 times that of the catalyst S6; the overall silicon-titanium molar ratio of the catalyst S6 is 44, the surface silicon-titanium molar ratio is 23, and the surface silicon-carbon molar ratio is 3.5; the toluene adsorption capacity of the catalyst S6 measured at 20℃, P / P0=0.1 and an adsorption time of 2h is 270mg / g; the mechanical strength of the catalyst S6 is 52N / cm.

[0096]

Example 7

[0097] (1) First, mix the corresponding amounts of water, tetrapropylammonium hydroxide, tetrabutyl titanate and tetraethyl orthosilicate uniformly in a molar ratio of SiO2:TiO2:tetrapropylammonium hydroxide:water of 1:0.2:0.4:15. Then, treat at 80°C for 8 hours and then at 150°C for 2 hours to obtain titanium-containing binder.

[0098] (2) Next, fumed silica, titanium-containing binder and guar gum powder are mixed evenly in a mass ratio of 1:1.5:0.2, stirred and kneaded for 4 hours to obtain a solid mixture with a certain viscosity. After mechanical extrusion molding, it is dried at 100°C for 8 hours and then calcined at 550°C for 6 hours to obtain a spherical catalyst precursor.

[0099] (3) A spherical catalyst precursor, hexamethyldisilazane and ethylenediamine were mixed in a mass ratio of 1:0.2:0.1 and treated at 120°C for 8 hours. After washing with ethanol and drying at 100°C for 8 hours, an olefin epoxide titanium silicon catalyst was obtained, denoted as S7.

[0100] The UV-Raman spectrum of catalyst S7 and Figure 1 Similarly, 364cm was observed. -1 500cm -1 1102cm -1 Spectral peak, 1102 cm⁻¹ -1 The peak intensity is 364 cm⁻¹ -1 The peak intensity is 8 times that of the catalyst S7; the overall silicon-titanium molar ratio of the catalyst S7 is 26, the surface silicon-titanium molar ratio is 12, and the surface silicon-carbon molar ratio is 3.4; the toluene adsorption capacity of the catalyst S7 measured at 20℃, P / P0=0.1 and an adsorption time of 2h is 312mg / g; the mechanical strength of the catalyst S7 is 75N / cm.

[0101]

Example 8

[0102] (1) First, mix the corresponding amounts of water, tetrapropylammonium hydroxide, tetrabutyl titanate and tetraethyl orthosilicate uniformly in a molar ratio of SiO2:TiO2:tetrapropylammonium hydroxide:water of 1:0.2:0.4:15. Then, treat at 80°C for 8 hours and then at 150°C for 2 hours to obtain titanium-containing binder.

[0103] (2) Next, fumed silica, titanium-containing binder and guar gum powder are mixed evenly in a mass ratio of 1:0.4:0.01, stirred and kneaded for 4 hours to obtain a solid mixture with a certain viscosity. After mechanical extrusion molding, it is dried at 100°C for 8 hours and then calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor.

[0104] (3) A cylindrical catalyst precursor, hexamethyldisilazane and ethylenediamine were mixed in a mass ratio of 1:0.2:0.1 and treated at 120°C for 8 hours. After washing with ethanol and drying at 100°C for 8 hours, an olefin epoxide titanium silicon catalyst was obtained, denoted as S8.

[0105] The UV-Raman spectrum of catalyst S8 and Figure 1 Similarly, 364cm was observed. -1 500cm -1 1102cm -1 Spectral peak, 1102 cm⁻¹ -1 The peak intensity is 364 cm⁻¹ -1 The peak intensity is 2.0 times that of the catalyst S8; the overall silicon-titanium molar ratio of the catalyst S8 is 98, the surface silicon-titanium molar ratio is 50, and the surface silicon-carbon molar ratio is 2.5; the toluene adsorption capacity of the catalyst S8 measured at 20℃, P / P0 = 0.1, and an adsorption time of 2h is 320 mg / g; the mechanical strength of the catalyst S8 is 50 N / cm.

[0106]

Example 9

[0107] (1) First, mix the corresponding amounts of water, tetrapropylammonium hydroxide, tetrabutyl titanate and tetraethyl orthosilicate uniformly in a molar ratio of SiO2:TiO2:tetrapropylammonium hydroxide:water of 1:0.2:0.4:15. Then, treat at 80°C for 8 hours and then at 150°C for 2 hours to obtain titanium-containing binder.

[0108] (2) Next, fumed silica, titanium-containing binder and guar gum powder are mixed evenly in a mass ratio of 1:1:0.1, stirred and kneaded for 4 hours to obtain a solid mixture with a certain viscosity. After mechanical extrusion molding, it is dried at 100°C for 8 hours and then calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor.

[0109] (3) A cylindrical catalyst precursor, dimethyldiethoxysilane and n-propylamine were mixed in a mass ratio of 1:0.1:0.5 and treated at 120°C for 8 hours. After washing with ethanol and drying at 100°C for 8 hours, an olefin epoxide titanium silicon catalyst was obtained, denoted as S9.

[0110] The UV-Raman spectrum of catalyst S9 and Figure 1 Similarly, 364cm was observed. -1 500cm -1 1102cm -1 Spectral peak, 1102 cm⁻¹ -1 The peak intensity is 364 cm⁻¹ -1 The peak intensity is 6.4 times that of the catalyst S9; the overall silicon-titanium molar ratio of the catalyst S9 is 32, the surface silicon-titanium molar ratio is 17, and the surface silicon-carbon molar ratio is 6; the toluene adsorption capacity of the catalyst S9 measured at 20℃, P / P0=0.1 and an adsorption time of 2h is 150mg / g; the mechanical strength of the catalyst S9 is 69N / cm.

[0111]

Example 10

[0112] (1) First, mix the corresponding amounts of water, tetrapropylammonium hydroxide, tetrabutyl titanate and tetraethyl orthosilicate uniformly in a molar ratio of SiO2:TiO2:tetrapropylammonium hydroxide:water of 1:0.2:0.4:15. Then, treat at 80°C for 8 hours and then at 150°C for 2 hours to obtain titanium-containing binder.

[0113] (2) Next, fumed silica, titanium-containing binder and guar gum powder are mixed evenly in a mass ratio of 1:1:0.1, stirred and kneaded for 4 hours to obtain a solid mixture with a certain viscosity. After mechanical extrusion molding, it is dried at 100°C for 8 hours and then calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor.

[0114] (3) The cylindrical catalyst precursor, octadecyldimethylmethoxysilane and hexamethylenediamine were mixed in a mass ratio of 1:0.02:0.02, treated at 180°C for 1 hour, washed with ethanol and dried at 100°C for 8 hours to obtain the olefin epoxide titanium silicon catalyst, denoted as S10.

[0115] The UV-Raman spectrum of the catalyst S10 and Figure 1 Similarly, 364cm was observed. -1 500cm -1 1102cm -1 Spectral peak, 1102 cm⁻¹ -1 The peak intensity is 364 cm⁻¹ -1The peak intensity is 4.7 times that of the catalyst S10; the overall silicon-titanium molar ratio of the catalyst S10 is 43, the surface silicon-titanium molar ratio is 21, and the surface silicon-carbon molar ratio is 0.6; the toluene adsorption capacity of the catalyst S10 measured at 20℃, P / P0=0.1 and an adsorption time of 2h is 450mg / g; the mechanical strength of the catalyst S10 is 55N / cm.

[0116]

Example 11

[0117] (1) First, mix the corresponding amounts of water, tetrapropylammonium hydroxide, tetrabutyl titanate and tetraethyl orthosilicate uniformly in a molar ratio of SiO2:TiO2:tetrapropylammonium hydroxide:water of 1:0.2:0.4:15. Then, treat at 80°C for 8 hours and then at 150°C for 2 hours to obtain titanium-containing binder.

[0118] (2) Next, fumed silica, titanium-containing binder and guar gum powder are mixed evenly in a mass ratio of 1:1:0.1, stirred and kneaded for 4 hours to obtain a solid mixture with a certain viscosity. After mechanical extrusion molding, it is dried at 100°C for 8 hours and then calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor.

[0119] (3) A cylindrical catalyst precursor, hexamethyldisilazane and methylamine were mixed at a mass ratio of 1:0.25:0.15 and treated at 100°C for 12 hours. After washing with ethanol and drying at 100°C for 8 hours, an olefin epoxide titanium silicon catalyst was obtained, denoted as S11.

[0120] The UV-Raman spectrum of the catalyst S11 and Figure 1 Similarly, 364cm was observed. -1 500cm -1 1102cm -1 Spectral peak, 1102 cm⁻¹ -1 The peak intensity is 364 cm⁻¹ -1 The peak intensity is 5.7 times that of the catalyst S11; the overall silicon-titanium molar ratio of the catalyst S11 is 36, the surface silicon-titanium molar ratio is 18, and the surface silicon-carbon molar ratio is 1; the toluene adsorption capacity of the catalyst S11 measured at 20℃, P / P0=0.1 and an adsorption time of 2h is 400mg / g; the mechanical strength of the catalyst S11 is 52N / cm.

[0121]

Example 12

[0122] (1) First, mix the corresponding amounts of water, tetrapropylammonium hydroxide, tetrabutyl titanate and tetraethyl orthosilicate uniformly in a molar ratio of SiO2:TiO2:tetrapropylammonium hydroxide:water of 1:0.2:0.4:15. Then, treat at 80°C for 8 hours and then at 150°C for 2 hours to obtain titanium-containing binder.

[0123] (2) Next, fumed silica, titanium-containing binder and guar gum powder are mixed evenly in a mass ratio of 1:1:0.1, stirred and kneaded for 4 hours to obtain a solid mixture with a certain viscosity. After mechanical extrusion molding, it is dried at 100°C for 8 hours and then calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor.

[0124] (3) A cylindrical catalyst precursor, hexamethyldisilazane and ethylenediamine were mixed in a mass ratio of 1:0.15:0.1 and treated at 80°C for 24 hours. After washing with ethanol and drying at 100°C for 8 hours, an olefin epoxide titanium silicon catalyst was obtained, denoted as S12.

[0125] The UV-Raman spectrum of the catalyst S12 and Figure 1 Similarly, 364cm was observed. -1 500cm -1 1102cm -1 Spectral peak, 1102 cm⁻¹ -1 The peak intensity is 364 cm⁻¹ -1 The peak intensity is 5.3 times that of the catalyst S12; the overall silicon-titanium molar ratio of the catalyst S12 is 37, the surface silicon-titanium molar ratio is 19, and the surface silicon-carbon molar ratio is 5; the toluene adsorption capacity of the catalyst S12 measured at 20℃, P / P0=0.1 and an adsorption time of 2h is 200mg / g; the mechanical strength of the catalyst S12 is 62N / cm.

[0126]

Examples 13-24

[0127] The olefin epoxidation titanium silicate catalysts prepared in Examples 1-12 were subjected to continuous liquid-phase epoxidation of propylene in a stainless steel fixed-bed reactor. 3 grams of olefin epoxidation titanium silicate catalyst were crushed into 20-40 mesh particles and filled into a stainless steel reaction tube, with glass beads at both ends. The reaction was carried out under liquid-phase epoxidation conditions at a temperature of 90°C and a pressure of 3.0 MPa, using a bottom-feed, top-discharge configuration. Nitrogen was used to balance the propylene pressure to 3.5 MPa to ensure complete propylene liquefaction. The propylene feedstock was fed separately and denoted as feedstock A. A cumene solution with an 80% cumene peroxide mass fraction was mixed with the solvent cumene and denoted as feedstock B. Both feedstocks were fed using plunger pumps and premixed before flowing through the catalyst bed. In the total feedstock stream, the propylene mass fraction was 20%, the propylene to hydrogen peroxide molar ratio was 1:0.15, and the total feedstock flow rate per unit mass of catalyst was 5 mL·g. cat. -1 ·h -1 The reaction liquid after flowing through the catalyst bed was collected, and the results are shown in Table 1.

[0128] Table 1 Catalytic performance of catalysts for propylene epoxidation in each example

[0129]

[0130]

[0131] a. The conversion and residual rates of cumene hydroperoxide were data at the beginning of the reaction;

[0132] b. During continuous reactions, the selectivity of propylene oxide and the ratio of main to byproducts remain stable;

[0133] c. Catalyst stabilization time refers to the running time from the start of the reaction until the conversion rate of cumene hydroperoxide is less than 98.0%, that is, the residual rate of cumene hydroperoxide in the reaction solution reaches 2%.

[0134] Comparative Example 1

[0135] (1) First, mix the corresponding amounts of water, tetrapropylammonium hydroxide and tetrapropylammonium hydroxide evenly with a molar ratio of SiO2:tetrapropylammonium hydroxide:water of 1:0.4:15. Then, treat at 80°C for 8 hours and then at 150°C for 2 hours to obtain the binder.

[0136] (2) Next, fumed silica, binder and guar gum powder are mixed evenly in a mass ratio of 1:1:0.1, stirred and kneaded for 4 hours to obtain a solid mixture with a certain viscosity. After mechanical extrusion molding, it is dried at 100℃ for 8 hours and then calcined at 550℃ for 6 hours to obtain a cylindrical catalyst precursor.

[0137] (3) A cylindrical catalyst precursor, hexamethyldisilazane and ethylenediamine were mixed in a mass ratio of 1:0.2:0.1 and treated at 120°C for 8 hours. After washing with ethanol and drying at 100°C for 8 hours, a titanium-silicon catalyst was obtained, denoted as D1.

[0138] The UV-Raman spectrum of catalyst D1 is as follows: Figure 2 As shown, 478cm was observed. -1 615cm -1 818cm -1 990cm -1 1102cm -1 The spectral peaks are all attributed to amorphous SiO2; the catalyst D1 does not contain titanium and has a surface silicon-to-carbon molar ratio of 2.4; the toluene adsorption capacity of the catalyst D1 measured at 20℃, P / P0 = 0.1 and an adsorption time of 2h is 330 mg / g; the mechanical strength of the catalyst D1 is 65 N / cm.

[0139] Comparative Example 2

[0140] (1) First, mix the corresponding amounts of water, tetrabutyl titanate and tetraethyl orthosilicate uniformly with a molar ratio of SiO2:TiO2:water of 1:0.2:15. Then, treat at 80°C for 8 hours and at 150°C for 2 hours to obtain a titanium-containing binder.

[0141] (2) Next, fumed silica, titanium-containing binder and guar gum powder are mixed evenly in a mass ratio of 1:1:0.1, stirred and kneaded for 4 hours to obtain a solid mixture with a certain viscosity. After mechanical extrusion molding, it is dried at 100°C for 8 hours and then calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor.

[0142] (3) A cylindrical catalyst precursor, hexamethyldisilazane and ethylenediamine were mixed in a mass ratio of 1:0.2:0.1 and treated at 120°C for 8 hours. After washing with ethanol and drying at 100°C for 8 hours, a titanium-silicon catalyst was obtained, denoted as D2.

[0143] The UV-Raman spectrum of catalyst D2 is as follows: Figure 3 As shown, 390cm was observed. -1 512cm -1 628cm -1 The spectral peaks are all attributed to TiO2; the overall silicon-titanium molar ratio of the catalyst D2 is 28, the surface silicon-titanium molar ratio is 13, and the surface silicon-carbon molar ratio is 3.1; the toluene adsorption capacity of the catalyst D2 measured at 20℃, P / P0=0.1, and an adsorption time of 2h is 292mg / g; the mechanical strength of the catalyst D2 is 54N / cm.

[0144] Comparative Example 3

[0145] (1) First, mix the corresponding amounts of water, tetrapropylammonium hydroxide, tetrabutyl titanate and tetraethyl orthosilicate uniformly in a molar ratio of SiO2:TiO2:tetrapropylammonium hydroxide:water of 1:0.2:0.4:15 to obtain a titanium-containing binder.

[0146] (2) Next, fumed silica, titanium-containing binder and guar gum powder are mixed evenly in a mass ratio of 1:1:0.1, stirred and kneaded for 4 hours to obtain a solid mixture with a certain viscosity. After mechanical extrusion molding, it is dried at 100°C for 8 hours and then calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor.

[0147] (3) A cylindrical catalyst precursor, hexamethyldisilazane and ethylenediamine were mixed in a mass ratio of 1:0.2:0.1 and treated at 120°C for 8 hours. After washing with ethanol and drying at 100°C for 8 hours, a titanium-silicon catalyst was obtained, denoted as D3.

[0148] The UV-Raman spectrum of catalyst D3 is as follows: Figure 4As shown, 485cm was observed. -1 1082cm -1 The spectral peaks are attributed to tetracoordinated titanium species in amorphous SiO2; the overall silicon-titanium molar ratio of catalyst D3 is 29, the surface silicon-titanium molar ratio is 14, and the surface silicon-carbon molar ratio is 2.9; the toluene adsorption capacity of catalyst D3 measured at 20℃, P / P0 = 0.1, and an adsorption time of 2h is 306 mg / g; the mechanical strength of catalyst D3 is 50 N / cm.

[0149] Comparative Example 4

[0150] (1) First, mix the corresponding amounts of water, tetrapropylammonium hydroxide, tetrabutyl titanate and tetraethyl orthosilicate uniformly in a molar ratio of SiO2:TiO2:tetrapropylammonium hydroxide:water of 1:0.2:0.4:15. Then, treat at 80°C for 8 hours and then at 150°C for 24 hours to obtain a titanium-containing binder.

[0151] (2) Next, fumed silica, titanium-containing binder and guar gum powder are mixed evenly in a mass ratio of 1:1:0.1, stirred and kneaded for 4 hours to obtain a solid mixture with a certain viscosity. After mechanical extrusion molding, it is dried at 100°C for 8 hours and then calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor.

[0152] (3) A cylindrical catalyst precursor, hexamethyldisilazane and ethylenediamine were mixed in a mass ratio of 1:0.2:0.1 and treated at 120°C for 8 hours. After washing with ethanol and drying at 100°C for 8 hours, a titanium-silicon catalyst was obtained, denoted as D4.

[0153] The UV-Raman spectrum of catalyst D4 is as follows: Figure 5 As shown, 380cm was observed. -1 514cm -1 1125cm -1 Spectral peak, 380cm -1 The spectral peak is attributed to the MFI framework, 514 cm⁻¹ -1 1125cm -1 The spectral peaks belong to tetracoordinate titanium species in the MFI framework; the overall silicon-titanium molar ratio of catalyst D4 is 30, the surface silicon-titanium molar ratio is 15, and the surface silicon-carbon molar ratio is 3.2; the toluene adsorption capacity of catalyst D4 measured at 20℃, P / P0 = 0.1, and an adsorption time of 2h is 284 mg / g; the mechanical strength of catalyst D4 is 42 N / cm.

[0154] Comparative Example 5

[0155] (1) First, mix the corresponding amounts of water, tetrapropylammonium hydroxide, tetrabutyl titanate and tetraethyl orthosilicate uniformly in a molar ratio of SiO2:TiO2:tetrapropylammonium hydroxide:water of 1:0.2:0.4:15. Then, treat at 80°C for 8 hours and then at 150°C for 2 hours to obtain titanium-containing binder.

[0156] (2) Next, fumed silica, titanium-containing binder and guar gum powder are mixed evenly in a mass ratio of 1:1:0.1, stirred and kneaded for 4 hours to obtain a solid mixture with a certain viscosity. After mechanical extrusion molding, it is dried at 100°C for 8 hours and then calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor.

[0157] (3) The cylindrical catalyst precursor and hexamethyldisilazane were mixed at a mass ratio of 1:0.2, treated at 120°C for 8 hours, washed with ethanol and dried at 100°C for 8 hours to obtain the titanium silicon catalyst, denoted as D5.

[0158] The UV-Raman spectrum of catalyst D5 is as follows: Figure 6 As shown, 350cm was observed. -1 517cm -1 782cm -1 1089cm -1 Spectral peak, 350cm -1 782cm -1 The spectral peak is related to the vibration of Si-O-Si, 517 cm⁻¹ -1 1089cm -1 The spectral peaks are related to the vibrations of the four-coordinate titanium species; the overall silicon-titanium molar ratio of the catalyst D5 is 30, the surface silicon-titanium molar ratio is 14, and the surface silicon-carbon molar ratio is 300; the toluene adsorption capacity of the catalyst D5 measured at 20℃, P / P0=0.1, and an adsorption time of 2h is 10mg / g; the mechanical strength of the catalyst D5 is 68N / cm.

[0159] Comparative Example 6

[0160] (1) First, mix the corresponding amounts of water, tetrapropylammonium hydroxide, tetrabutyl titanate and tetraethyl orthosilicate uniformly in a molar ratio of SiO2:TiO2:tetrapropylammonium hydroxide:water of 1:0.2:0.4:15. Then, treat at 80°C for 8 hours and then at 150°C for 2 hours to obtain titanium-containing binder.

[0161] (2) Next, fumed silica, titanium-containing binder and guar gum powder are mixed evenly in a mass ratio of 1:1:0.1, stirred and kneaded for 4 hours to obtain a solid mixture with a certain viscosity. After mechanical extrusion molding, it is dried at 100°C for 8 hours and then calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor.

[0162] (3) The cylindrical catalyst precursor and ethylenediamine were mixed at a mass ratio of 1:0.1, treated at 120°C for 8 hours, washed with ethanol and dried at 100°C for 8 hours to obtain the titanium silicon catalyst, denoted as D6.

[0163] The UV-Raman spectrum of catalyst D6 is as follows: Figure 7 As shown, 356cm was observed. -1 519cm -1 945cm -1 1094cm -1 Spectral peak, 356cm -1 The spectral peak is related to the vibration of Si-O-Si, 519 cm⁻¹ -1 945cm -1 1094cm -1 The spectral peaks are related to the vibrations of the four-coordinate titanium species; the overall silicon-titanium molar ratio of the catalyst D6 is 34, the surface silicon-titanium molar ratio is 16, and the surface silicon-carbon molar ratio is 40; the toluene adsorption capacity of the catalyst D6 measured at 20℃, P / P0=0.1, and an adsorption time of 2h is 65mg / g; the mechanical strength of the catalyst D6 is 64N / cm.

[0164] Comparative Example 7

[0165] (1) First, mix the corresponding amounts of water, tetrapropylammonium hydroxide, tetrabutyl titanate and tetraethyl orthosilicate uniformly with a molar ratio of SiO2:TiO2:tetrapropylammonium hydroxide:water of 1:0.2:0.4:15, and treat at 150°C for 30 hours to obtain titanium-containing binder.

[0166] (2) Next, fumed silica, titanium-containing binder and guar gum powder are mixed evenly in a mass ratio of 1:1:0.1, stirred and kneaded for 4 hours to obtain a solid mixture with a certain viscosity. After mechanical extrusion molding, it is dried at 100°C for 8 hours and then calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor.

[0167] (3) A cylindrical catalyst precursor, hexamethyldisilazane and ethylenediamine were mixed in a mass ratio of 1:0.2:0.1 and treated at 120°C for 8 hours. After washing with ethanol and drying at 100°C for 8 hours, an olefin epoxide titanium silicon catalyst was obtained, denoted as D7.

[0168] The UV-Raman spectrum of catalyst D7 and Figure 5 Similarly, 380cm was observed. -1 515cm -1 1124cm -1The spectral peaks show that the overall silicon-titanium molar ratio of catalyst D7 is 29, the surface silicon-titanium molar ratio is 14, and the surface silicon-carbon molar ratio is 3.1; the toluene adsorption capacity of catalyst D7 measured at 20℃, P / P0=0.1, and an adsorption time of 2h is 280mg / g; the mechanical strength of catalyst D7 is 45N / cm.

[0169] Comparative Examples 8-14

[0170] The titanium-silicon catalysts D1 to D7 obtained in Comparative Examples 1 to 7 were subjected to continuous liquid-phase epoxidation of propylene under the reaction conditions of Examples 13 to 24, respectively. The reaction results are shown in Table 2 below:

[0171] Table 2 Catalytic performance of each comparative catalyst for propylene epoxidation

[0172]

[0173] The specific embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An olefin epoxide titanium silicate catalyst, the ultraviolet Raman spectrum of which is at 364±6 cm⁻¹ -1 500±6 cm -1 and 1102±6cm -1 A spectral peak appears at [location], among which, 1102±6 cm -1 The intensity of the spectral peak is 364±6 cm⁻¹. -1 The peak intensity is 1.0 to 10.0 times that of the molecular sieve; the titanium-silicon catalyst comprises silicon, titanium, and carbon, with an overall silicon-to-titanium molar ratio of 20 to 200; a surface silicon-to-titanium molar ratio of 10 to 100; and a surface silicon-to-carbon molar ratio of 0.5 to 6.0; the toluene adsorption capacity of the titanium-silicon catalyst measured at 20 °C, P / P0 = 0.1, and an adsorption time of 2 h is 150 to 450 mg / g molecular sieve.

2. The titanium-silicon catalyst according to claim 1, characterized in that: 1102±6cm -1 The intensity of the spectral peak is 364±6 cm⁻¹. -1 The intensity of the spectral peak is 3.0 to 8.0 times that of the peak.

3. The titanium-silicon catalyst according to claim 1, characterized in that: The titanium-silicon catalyst comprises silicon, titanium, and carbon, with an overall silicon-to-titanium molar ratio of 25-100; a surface silicon-to-titanium molar ratio of 12-50; and a surface silicon-to-carbon molar ratio of 1.0-5.

0.

4. The titanium-silicon catalyst according to claim 1, characterized in that: The toluene adsorption capacity of the titanium-silicon catalyst, measured at 20 °C, P / P0 = 0.1, and an adsorption time of 2 h, was 250~400 mg / g molecular sieve.

5. The titanium-silicon catalyst according to claim 1, characterized in that: The mechanical strength of the titanium-silicon catalyst is 40~90 N / cm.

6. The titanium-silicon catalyst according to claim 5, characterized in that: The mechanical strength of the titanium-silicon catalyst is 50~80 N / cm.

7. A method for preparing an olefin epoxide titanium silica catalyst, comprising the following steps: (1) A titanium-containing binder is prepared by mixing silicon source A, titanium source, organic base and water and hydrothermally treating the mixture. (2) The silicon source B, the titanium-containing binder and the pore-forming agent from step (1) are kneaded together and calcined to obtain the catalyst precursor; (3) The catalyst precursor from step (2) is contacted with a mixture of organosilanes and organic amines to obtain the titanium-silicon catalyst; The proportions of each material in step (1), expressed as a molar ratio, are as follows: silicon source A is SiO2: titanium source is TiO2: organic base: water = 1:x:y:z; where x = 0.01~0.5, y = 0.05~0.5, z = 5~25; The hydrothermal treatment in step (1) is carried out in stages; the first stage hydrothermal treatment conditions are: 60~119 ℃ for 1~24 hours; the second stage hydrothermal treatment conditions are: 120~180 ℃ for 0.5~6 hours; the temperature of the second stage hydrothermal treatment is 10~120 ℃ higher than that of the first stage hydrothermal treatment. The proportions of each material in step (2) are as follows: the mass ratio of silicon source B (calculated as SiO2), titanium-containing binder in step (1), and pore-forming agent is 1:0.2~1.8:0.01~0.

3. In step (3), the mass ratio of the catalyst precursor to the organosilane and the organic amine is 1:0.01~0.5:0.01~0.5; The organosilane is selected from at least one of hexamethyldisilazane, triethylchlorosilane, chloromethyl(dimethyl)methoxysilane, octadecyldimethylmethoxysilane, ethoxytrimethylsilane, triallylethoxysilane, dimethyldiethoxysilane, and methylphenyldimethoxysilane; the organoamine is selected from at least one of methylamine, ethylamine, ethylenediamine, n-propylamine, n-butylamine, diethylamine, triethylamine, and hexamethylenediamine.

8. The preparation method according to claim 7, characterized in that: The proportions of each material in step (1), expressed as a molar ratio, are as follows: silicon source A is SiO2: titanium source is TiO2: organic base: water = 1:x:y:z; where x = 0.05~0.3, y = 0.1~0.4, z = 12~20; And / or, the silicon source A is selected from at least one of tetraethyl orthosilicate, fumed silica, and silica sol; the titanium source is selected from at least one of tetrabutyl titanate, tetraisopropyl titanate, titanium tetrachloride, hexafluorotitanic acid, and ammonium hexafluorotitanate; the organic base is selected from at least one of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, dimethyl diethylammonium hydroxide, dimethyl diisopropylammonium hydroxide, piperidine, and hexamethyleneimine.

9. The preparation method according to claim 7, characterized in that: The silicon source A is selected from at least one of tetraethyl orthosilicate and silica sol; the titanium source is selected from at least one of tetrabutyl titanate, tetraisopropyl titanate, and hexafluorotitanic acid; the organic base is selected from at least one of tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, dimethyldiethylammonium hydroxide, and dimethyldiisopropylammonium hydroxide.

10. The preparation method according to claim 7, characterized in that: The hydrothermal treatment in step (1) is carried out in stages; the first stage hydrothermal treatment conditions are: 80~100 ℃ for 2~20 hours; the second stage hydrothermal treatment conditions are: 130~170 ℃ for 2~5 hours. And / or, the temperature of the second stage hydrothermal treatment is 20~100 ℃ higher than the temperature of the first stage hydrothermal treatment.

11. The preparation method according to claim 7, characterized in that: The proportions of each material in step (2) are as follows: the mass ratio of silicon source B (calculated as SiO2), titanium-containing binder in step (1), and pore-forming agent is 1:0.3~1.5:0.05~0.

2. And / or, the silicon source B is selected from at least one of fumed silica or silicon powder; the pore-forming agent is selected from at least one of guar gum powder, cellulose, chitosan, lignin, starch, polyethylene glycol, triblock copolymer P123, and F127.

12. The preparation method according to claim 7, characterized in that: The roasting conditions in step (2) are: roasting at 450~650 ℃ in an oxygen-containing atmosphere for 4~12 hours.

13. The preparation method according to claim 7, characterized in that: In step (3), the mass ratio of the catalyst precursor to organosilane and organic amine is 1:0.05~0.40:0.05~0.40; And / or, the organosilane is selected from at least one of hexamethyldisilazane, triethylchlorosilane, and chloromethyl(dimethyl)methoxysilane; the organic amine is selected from at least one of methylamine, ethylamine, ethylenediamine, n-propylamine, n-butylamine, and diethylamine.

14. The preparation method according to claim 7, characterized in that: The treatment conditions in step (3) are: 80~180 ℃ for 0.5~24 hours.

15. The preparation method according to claim 7, characterized in that: The treatment conditions in step (3) are: 100~160 ℃ for 1~12 hours.

16. The titanium-silicon catalyst prepared by the preparation method according to any one of claims 7 to 15.

17. The use of the titanium-silicon catalyst according to any one of claims 1 to 6 or the titanium-silicon catalyst according to claim 16 in the epoxidation reaction of olefins.

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