Titanium silicon molecular sieve, nanogold supported titanium silicon molecular sieve catalyst, and its manufacturing method and use

Abstract

The present invention provides a titanium silicon molecular sieve, a nano gold supported titanium silicon molecular sieve catalyst, a catalyst preparation method and its use. The titanium silicon molecular sieve has a micropore specific surface area of ​​320-500 m 2 / g, micropore volume is 0.1-0.4 cm 3 / g, mesopore specific surface area is 50-100m 2 / g, mesopore volume is 0.075-0.1 cm 3 / g, particle diameter of 100 to 250 nm, ratio of micropore specific surface area to total specific surface area of ​​50 to 90%. The catalyst contains a titanium silicon molecular sieve carrier and nanogold supported thereon, and has a micropore volume of 0.06 to 0.4 cm 3 / g, micropore specific surface area is 160~450m 2 / g, mesopore volume is 0.05-0.08 cm 3 / g, mesopore specific surface area is 40-85m 2 / g and particle size is 100-250nm. The method for producing the catalyst includes the steps of alkali-treating the titanium silicon molecular sieve with an aliphatic amine aqueous solution and then supporting nanogold. The catalyst is used in olefin epoxidation reaction, cycloolefin epoxidation reaction, phenol hydroxylation reaction, and cyclohexanone ammonia ammoximation reaction. By supporting nanogold particles on the titanium silicon molecular sieve with specific physical property parameters, the dispersibility of nanogold is increased. When the catalyst is used in propylene gas phase epoxidation reaction, the catalytic activity is high, the conversion rate of propylene is improved to 8%-14%, and the selectivity of propylene oxide is improved to 90-99%.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of Chinese Patent Application No. 202111579941.1 filed on December 22, 2021, the contents of which are incorporated herein by reference.

[0002] This application claims the benefit of Chinese Patent Application No. 202111579946.4, filed on December 22, 2021, the contents of which are incorporated herein by reference.

[0003] This application claims the benefit of Chinese Patent Application No. 202210239081.5, filed on March 11, 2022, the contents of which are incorporated herein by reference. [Technical Field]

[0004] The present invention relates to the field of hydrooxidation reactions, in particular to titanium silicon molecular sieves, nanogold supported titanium silicon molecular sieve catalysts, and methods for preparing and using the same. [Background technology]

[0005] Heteroatomic molecular sieves, with their regular topological structure and unique acidic properties owing to the introduction of framework metal atoms, have become a research hotspot in the fields of chemistry and chemical engineering. In 1983, Taramasso et al. first reported the TS-1 molecular sieve, in which transition metal titanium atoms replaced a small number of framework silicon atoms in an all-silicon MFI molecular sieve. This means that titanium atoms are embedded in the framework of the molecular sieve in a tetrahedral configuration. Because framework titanium species possess Lewis acidity, their vacant orbitals can accept electrons from oxygen atoms in H2O2 molecules. Therefore, TS-1 molecular sieves can efficiently activate H2O2 molecules with various functional organic compounds for selective oxidation reactions, such as olefin epoxidation, cycloolefin epoxidation, phenol hydroxylation, and cyclohexanone ammoximation. Compared to conventional oxidation processes, the H2O2 / TS-1 catalytic oxidation process has the advantages of mild reaction conditions, environmental friendliness, and efficiency.

[0006] Currently, the H2O2 / TS-1 catalytic oxidation system is used in several industrial applications, such as propylene epoxidation (HPPO) and cyclohexanone ammoximation. While this catalytic system offers many advantages, its widespread adoption poses several challenges due to the need for hydrogen peroxide production equipment. Hydrogen peroxide storage and transportation requirements are strict, and the need for on-site production equipment limits process layout. High-concentration hydrogen peroxide is also difficult to prepare, posing storage safety concerns. To fundamentally address these limitations, researchers have explored the direct catalysis of the selective oxidation of organic matter in a hydrogen (H2) and oxygen (O2) atmosphere. Gas-phase selective oxidation technology allows for more flexible industrial layout and meets the development needs for environmentally friendly, efficient, and low-carbon development.

[0007] To achieve hydrooxidation, it is necessary to improve the catalyst that can simultaneously synthesize H2O2 from hydrogen and oxygen in situ and oxidize organic matter. Summary of the Invention [Problem to be solved by the invention]

[0008] The objective of the present invention is to provide a titanium silicon molecular sieve, a manufacturing method thereof, a nanogold-supported titanium silicon molecular sieve catalyst, and a manufacturing method and use thereof, in order to solve the problems of the low micropore volume and the low micropore specific surface area of ​​the TS-1 molecular sieve support in the prior art, and the problems of controlling the dispersion of metal nanoparticles supported thereon. [Means for solving the problem]

[0009] In order to achieve the above object, the first aspect of the present invention comprises: Micropore specific surface area is 320-500m 2 / g, micropore volume 0.1-0.4 cm 3 / g, mesopore specific surface area is 50-100m 2 / g, mesopore volume 0.075 to 0.1 cm 3 / g, particle diameter is 100 to 250 nm, and the ratio of micropore specific surface area to the total specific surface area is 50% to 90%.

[0010] A second aspect of the present invention is A titanium silicon molecular sieve carrier and nanogold supported on the carrier, the micropore volume of which is 0.06 to 0.4 cm 3 / g, micropore specific surface area is 160~450m 2 / g, mesopore volume 0.05-0.08 cm 3 / g, mesopore specific surface area is 40-85m 2 / g and a particle size of 100 to 250 nm.

[0011] A third aspect of the present invention is The method includes the steps of: treating titanium silicon molecular sieve with an aqueous aliphatic amine solution to form an alkali; and then supporting nanogold on the titanium silicon molecular sieve to obtain the catalyst; The titanium silicon molecular sieve is the titanium silicon molecular sieve according to the first embodiment, and the method for producing the nanogold-supported titanium silicon molecular sieve catalyst is provided.

[0012] A fourth aspect of the present invention provides a nanogold-supported titanium silicon molecular sieve catalyst produced by the method according to the third aspect.

[0013] A fifth aspect of the present invention provides use of the nanogold-supported titanium silicon molecular sieve catalyst according to the second or fourth aspect in olefin epoxidation, cycloolefin epoxidation, phenol hydroxylation, and cyclohexanone ammonia ammoximation. [Effects of the Invention]

[0014] According to the above technical solution, the present invention supports nanogold particles on titanium silicon molecular sieves with specific physical properties, resulting in high dispersion of nanogold in the resulting nanogold-supported titanium silicon molecular sieve catalyst. When this catalyst is used in the gas-phase epoxidation of propylene, it has high catalytic activity, improving the propylene conversion rate to 8%-14% and the selectivity to propylene oxide to 90%-99%. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a diagram showing a reaction scheme for propylene vapor phase epoxidation in the present invention. [Figure 2] FIG. 2 is a pore size distribution diagram of the micropores of the titanium silicon molecular sieves obtained in Production Examples 1 and 7 of the present invention. [Figure 3] FIG. 2 is a pore size distribution diagram of the titanium silicon molecular sieves obtained in Production Examples 1 and 8 of the present invention. [Figure 4] 1 is a HAADF-STEM image of the catalyst obtained in Example 3 of the present invention. [Figure 5] 1 is a HAADF-STEM image of the catalyst obtained in Comparative Example 5 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] The endpoints of ranges and any values ​​disclosed herein are not intended to be limiting to the exact ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, values ​​between the individual range endpoints, between the individual range endpoints and the individual point values, and between the individual point values ​​can be combined with each other to form one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed herein.

[0017] In the first aspect of the present invention, the micropore specific surface area is 320 to 500 m 2 / g, micropore volume 0.1-0.4 cm 3 / g, mesopore specific surface area is 50-100m 2 / g, mesopore volume 0.075 to 0.1 cm 3 / g, particle diameter is 100 to 250 nm, and the ratio of micropore specific surface area to the total specific surface area is 50% to 90%.

[0018] In the present invention, the micropores refer to pores having a diameter of 2 nm or less in the porous structure of the titanium silicon molecular sieve.

[0019] In the present invention, the micropore specific surface area and micropore volume of the titanium silicon molecular sieve are calculated by measuring the static N2 adsorption / desorption curve of the sample at liquid nitrogen temperature using a Micromeritics ASAP 2460 static nitrogen adsorption apparatus, and then analyzing and calculating the curve using the t-plot method.

[0020] In the present invention, the mesopore specific surface area and mesopore volume of the titanium silicon molecular sieve are calculated by measuring the static N2 adsorption / desorption curve of the sample at liquid nitrogen temperature using a Micromeritics ASAP 2460 static nitrogen adsorption apparatus, and then analyzing the curve using the BJH method.

[0021] In the present invention, the total specific surface area of ​​the titanium silicon molecular sieve is measured by the BET method.

[0022] In the present invention, the particle size of the titanium silicon molecular sieve is observed by a high angle annular dark field scanning transmission electron microscope (HAADF-STEM).

[0023] The micropore specific surface area of ​​the titanium silicon molecular sieve is 320m 2 / g, 350m 2 / g, 400m 2 / g, 405m 2 / g, 410m 2 / g, 445m 2 / g, 480m 2 / g, 500m 2 / g, and any value within the range consisting of any two of the above values.

[0024] The micropore volume of the titanium silicon molecular sieve is 0.1 cm 3 / g, 0.15cm 3 / g, 0.165cm 3 / g, 0.2cm 3 / g, 0.238cm 3 / g, 0.3cm 3 / g, 0.355cm 3 / g, 0.389cm 3 / g, 0.4cm 3 / g, and any value within the range consisting of any two of the above values.

[0025] The mesopore specific surface area of ​​the titanium silicon molecular sieve is 50m 2 / g, 60m 2 / g, 72m 2 / g, 80m 2 / g, 90m 2 / g, 95m 2 / g, 100m 2 / g, and any value within the range consisting of any two of the above values.

[0026] The mesopore volume of the titanium silicon molecular sieve is 0.075 cm 3 / g, 0.085cm 3 / g, 0.09cm 3 / g, 0.095cm 3 / g, 0.1cm 3 / g, and any value within the range consisting of any two of the above values.

[0027] The particle size of the titanium silicon molecular sieve may be selected from the following ranges: 100 nm, 125 nm, 140 nm, 158 nm, 180 nm, 200 nm, 215 nm, 230 nm, 245 nm, 250 nm, and any two of the above values.

[0028] The ratio of the micropore specific surface area to the total specific surface area of ​​the titanium silicon molecular sieve may be selected from the range of 50%, 60%, 70%, 80%, 90%, and any two of the above values.

[0029] In one preferred embodiment of the present invention, the titanium silicon molecular sieve has a micropore specific surface area of ​​350 to 480 m 2 / g, micropore volume 0.13~0.37cm 3 / g, mesopore specific surface area is 70-100m 2 / g, mesopore volume 0.08-0.1 cm 3 / g, particle diameter is 150 to 210 nm, and the ratio of the micropore specific surface area to the total specific surface area is 60% to 90%.

[0030] In one preferred embodiment of the present invention, in the titanium silicon molecular sieve, 130%<surface Ti / Si (mol%) / bulk phase Ti / Si (mol%)×100%<220%.

[0031] In the present invention, the titanium content and silicon content of the surface of the titanium silicon molecular sieve are measured by X-ray photoelectron spectroscopy (XPS), and the surface Ti / Si (mol%) of the sample is obtained by comparing the molar amounts of both. The titanium content and silicon content of the bulk phase of the titanium silicon molecular sieve are measured by X-ray fluorescence spectroscopy (XRF), and the bulk phase Ti / Si (mol%) of the sample is obtained by comparing the molar amounts of both. The surface refers to the surface layer of the titanium silicon molecular sieve particle, which can be measured by XPS, and has a theoretical depth of 8 to 10 nm. The bulk phase refers to the entire titanium silicon molecular sieve particle.

[0032] In one preferred embodiment of the present invention, in the titanium silicon molecular sieve, 145%<surface Ti / Si (mol%) / bulk phase Ti / Si (mol%)×100%<200%.

[0033] In one preferred embodiment of the present invention, the molar ratio of titanium to silicon in the titanium silicon molecular sieve is 0.001-0.04:1, preferably 0.005-0.025:1.

[0034] According to the present invention, the method for producing the titanium silicon molecular sieve includes: (1) uniformly mixing a silicon source, an alkaline template agent, a titanium source, water, and an alcohol compound to obtain a titanium silicon sol; (2) adding a compound represented by formula (I) to the titanium silicon sol, and subjecting the resulting mixture to hydrothermal crystallization and calcination to obtain a titanium silicon molecular sieve;

[0035] [ka]

[0036] wherein i is an integer from 1 to 6; R1, R2, and R3 are each independently selected from C1 to C6 alkyl; R4 and R5 are each independently selected from hydrogen, methyl, and ethyl; R6 is selected from methyl, -SH, and -NHR7; and R7 is selected from hydrogen or C1 to C6 alkyl.

[0037] In the present invention, C1-C6 alkyl refers to alkyl having a total of 1 to 6 carbon atoms, and may be, for example, one of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, and n-hexyl.

[0038] In some preferred embodiments of the present invention, R1, R2, and R3 are each independently selected from C1-C3 alkyl, which may be methyl, ethyl, n-propyl, or isopropyl, and preferably R1, R2, and R3 are each independently selected from methyl, ethyl, or n-propyl. In the present invention, R1, R2, and R3 may be the same or different, and in preferred conditions, R1, R2, and R3 are all the same.

[0039] In the present invention, the compound represented by formula (I) is used as a silanizing reagent to form a titanium-silicon molecular sieve with a micropore structure during a hydrothermal crystallization reaction. Furthermore, this titanium-silicon molecular sieve possesses numerous micropores, resulting in a high micropore specific surface area and micropore volume, as well as a high surface titanium content (as indicated by a higher surface Ti / Si ratio than the bulk Ti / Si ratio). When this titanium-silicon molecular sieve is used as a catalyst or catalyst support in a reaction, compared to a titanium-silicon molecular sieve with mesopore channels, the confined space formed by the micropore channels more favorably promotes collisions between reactant molecules and the framework titanium active centers on the pore walls, leading to further adsorption and chemical reactions, thereby improving the conversion of the reactants. Furthermore, the increased secondary micropore structure shortens the molecular diffusion path, providing abundant mass transfer channels for increasing the diffusion rate of reactant and product molecules, and promoting the timely desorption of product molecules to avoid side reactions and improve selectivity. This feature of high titanium content on the surface significantly shortens the diffusion path of reactant and product molecules, improves the contact efficiency between reactants and active centers and the desorption and outward diffusion effect of product molecules, and further enhances the conversion rate of reactants and the selectivity of products.

[0040] In the present invention, when R6 of the compound represented by formula (I) is methyl, a titanium-silicon molecular sieve with a secondary micropore structure is formed during the hydrothermal crystallization reaction due to weak intermolecular interactions between the alkyl chains of the silanizing reagent. When R6 of the compound represented by formula (I) is -SH, a titanium-silicon molecular sieve with a secondary micropore structure is formed during the hydrothermal crystallization reaction due to electrostatic forces between the thiols of the silanizing reagent. When R6 of the compound represented by formula (I) is -NHR7, a titanium-silicon molecular sieve with a secondary micropore structure is formed during the hydrothermal crystallization reaction due to hydrogen bonding between the amino groups of the silanizing reagent and the flexible interaction of the external short-chain alkyl (R7) linked to the amino group. The secondary micropore structure refers to the increased micropore structure obtained by adding the silanizing reagent in addition to the inherent micropores of the titanium-silicon molecular sieve.

[0041] In the present invention, if the amount of silanizing reagent (compound represented by formula (I)) used is too large, the crystallization properties of the titanium silicon sol will be reduced, and the molecular sieve will not be obtained. If the amount of silanizing reagent (compound represented by formula (I)) used is too small, the micropore specific surface area and micropore volume of the obtained titanium silicon molecular sieve will be reduced, affecting the mass transfer efficiency and, as a result, its catalytic activity. Under preferred conditions, in step (1), the silicon source is calculated as SiO2, and the alkaline template agent is calculated as N if it contains nitrogen, or as OH if it does not contain nitrogen. ー When the titanium source is calculated as TiO2, the molar ratio of the silicon source, alkaline template agent, titanium source, water, alcohol compound, and compound represented by formula (I) is 1:(0.05-0.4):(0.001-0.04):(5-40):(0.1-10):(0.01-0.3), preferably 1:(0.1-0.3):(0.005-0.025):(5-25):(0.1-5):(0.01-0.2).

[0042] In one preferred embodiment of the present invention, the silicon source is at least one selected from tetramethyl silicate, tetraethyl silicate, tetrapropyl silicate, tetrabutyl silicate, white carbon black, and silica sol.

[0043] In one preferred embodiment of the present invention, the alkaline template agent is at least one selected from a quaternary ammonium base, an aliphatic amine, and an aliphatic alcohol amine, preferably at least one selected from tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide.

[0044] In one preferred embodiment of the present invention, the titanium source is selected from organic and / or inorganic titanium sources.

[0045] In one preferred embodiment of the present invention, the titanium source is at least one selected from titanium tetrachloride, titanium sulfate, titanium nitrate, tetraethyl titanate, tetrapropyl titanate, and tetrabutyl titanate.

[0046] In one preferred embodiment of the present invention, the alcohol compound is a C1-C4 alcohol, preferably isopropyl alcohol.

[0047] According to the present invention, under preferred conditions, step (1) further includes: first stirring and mixing a silicon source, an alkaline template agent, and water to obtain a mixed system; and then adding a mixed solution of a titanium source and an alcohol compound dropwise to the mixed system and second stirring the mixed solution to obtain a mixed solution.

[0048] In the present invention, the dropping speed of the mixed liquid is preferably 0.01 to 0.5 mL / min, and more preferably 0.1 to 0.5 mL / min.

[0049] In the present invention, the first stirring time is preferably 0.1 to 2 hours.

[0050] In the present invention, the second stirring time is preferably 0.5 to 6 hours, and more preferably 0.5 to 3 hours.

[0051] In the present invention, step (1) preferably further comprises removing alcohol from the mixed solution, which can remove alcohol generated by hydrolysis of the silicon source and titanium source. In the present invention, it is preferable to remove the alcohol generated in the system by azeotropic distillation. Furthermore, when removing the alcohol, water lost by azeotropic distillation is replenished so that the blending ratio of each substance in the titanium silicon sol satisfies the above requirements. Preferably, the conditions for removing the alcohol are a temperature of 30 to 100°C and a time of 2 to 10 hours, preferably a temperature of 40 to 90°C and a time of 4 to 10 hours.

[0052] According to the present invention, in order to uniformly disperse the silanization reagent in the titanium silicon sol, under preferred conditions, step (2) further comprises adding the compound represented by formula (I) to the titanium silicon sol and carrying out third stirring for 0.1 to 24 hours, and preferably, the third stirring time is 0.5 to 10 hours, more preferably 1 to 3 hours.

[0053] In the present invention, rapid temperature increase allows for control of the nucleation and growth rate of molecular sieves at low temperatures. This results in smaller molecular sieve particles, which can be loaded with nanogold for catalytic reactions, thereby shortening the internal diffusion path of the product and improving selectivity. Rapid temperature increase also promotes rapid hydrolysis of the silanizing reagent during the molecular sieve growth process, resulting in the construction of a secondary micropore structure. According to the present invention, in step (2), the hydrothermal crystallization is preferably performed by heating the mixture to a crystallization temperature within 0.1 to 1 hour and then crystallizing at the crystallization temperature for 10 to 100 hours. The crystallization temperature is 50 to 200°C, preferably 100 to 200°C for 20 to 80 hours, more preferably 0.1 to 0.5 hours. More preferably, the hydrothermal crystallization is performed at a temperature of 120 to 180°C for 20 to 80 hours. Under the above-mentioned preferable conditions, the specific micropore surface area and the specific micropore volume of the molecular sieve can be balanced to produce a molecular sieve having a specific specific micropore surface area and specific micropore volume.

[0054] In the present invention, the pressure for hydrothermal crystallization is not particularly limited, and may be the autogenous pressure of the crystallization system.

[0055] According to the present invention, under preferred conditions, the method further comprises washing, filtering, and drying the product obtained by hydrothermal crystallization. The washing, filtering, and drying processes are each known to those skilled in the art. For example, the washing temperature may be 20 to 50°C, the washing solvent may be water, and the amount of the washing solvent may be 1 to 20 times the mass of the crystallized product. The drying conditions may be a temperature of 40 to 150°C and a time of 0.5 to 24 hours.

[0056] In one preferred embodiment of the present invention, in step (2), the roasting conditions are a temperature of 400 to 800°C and a time of 1 to 15 hours.

[0057] A second aspect of the present invention is a method for producing a titanium silicon molecular sieve carrier, comprising: a titanium silicon molecular sieve carrier; and nanogold supported on the carrier; the carrier having a micropore volume of 0.06 to 0.4 cm. 3 / g, micropore specific surface area is 160~450m 2 / g, mesopore volume 0.05-0.08 cm 3 / g, mesopore specific surface area is 40-85m 2 / g and a particle size of 100 to 250 nm.

[0058] In the present invention, the micropore specific surface area and micropore volume of the catalyst were calculated by measuring the static N adsorption / desorption curve of the sample at liquid nitrogen temperature using a Micromeritics ASAP 2460 static nitrogen adsorption apparatus, and then analyzing the curve using the t-plot method.

[0059] In the present invention, the mesopore specific surface area and mesopore volume of the catalyst were calculated by measuring the static N2 adsorption / desorption curve of the sample at liquid nitrogen temperature using a Micromeritics ASAP 2460 static nitrogen adsorption apparatus, and then analyzing the curve using the BJH method.

[0060] In the present invention, the particle size of the catalyst is observed by a high angle annular dark field scanning transmission electron microscope (HAADF-STEM).

[0061] The micropore volume of the catalyst is 0.06 cm 3 / g, 0.1cm 3 / g, 0.15cm 3 / g, 0.2cm 3 / g, 0.25cm 3 / g, 0.3cm 3 / g, 0.35cm 3 / g, 0.4cm 3 / g, and any value within the range consisting of any two of the above values.

[0062] The micropore specific surface area of ​​the catalyst is 160 m 2 / g, 200m 2 / g, 250m 2 / g, 280m 2 / g, 300m 2 / g, 320m 2 / g, 360m 2 / g, 400m 2 / g, 420m 2 / g, 450m 2 / g, and any value within the range consisting of any two of the above values.

[0063] The mesopore volume of the catalyst is 0.05 cm 3 / g, 0.06cm 3 / g, 0.07cm 3 / g, 0.08cm 3 / g, and any value within the range consisting of any two of the above values.

[0064] The mesopore specific surface area of ​​the catalyst is 40 m 2 / g, 50m 2 / g, 60m 2 / g, 70m 2 / g, 75m 2 / g, 80m 2 / g, 85m 2 / g, and any value within the range consisting of any two of the above values.

[0065] The particle size of the catalyst may be selected from 100 nm, 120 nm, 140 nm, 150 nm, 180 nm, 200 nm, 220 nm, 240 nm, 250 nm, and any value within a range consisting of any two of the above values.

[0066] In one preferred embodiment of the present invention, the micropore volume of the catalyst is 0.1 to 0.3 cm 3 / g, micropore specific surface area is 260~410m 2 / g, mesopore volume is 0.058-0.078 cm 3 / g, mesopore specific surface area is 45-80m 2 / g, and the particle size is 150 to 210 nm.

[0067] In one preferred embodiment of the present invention, in the catalyst, 130%<surface Ti / Si (mol %) / bulk phase Ti / Si (mol %)×100%<220%.

[0068] In the present invention, the titanium content and silicon content of the surface of the catalyst are measured by an X-ray photoelectron spectrometer (XPS), and the surface Ti / Si (mol%) of the sample is obtained by comparing the molar amounts of both. The titanium content and silicon content of the bulk phase of the catalyst are measured by an X-ray fluorescence spectrometer (XRF), and the bulk phase Ti / Si (mol%) of the sample is obtained by comparing the molar amounts of both. The surface refers to the surface layer of the titanium silicon molecular sieve particles, which can be measured by XPS, and has a theoretical depth of 8 to 10 nm, and the bulk phase refers to the entire titanium silicon molecular sieve particles.

[0069] In one preferred embodiment of the present invention, in the catalyst, 145%<surface Ti / Si (mol %) / bulk phase Ti / Si (mol %)×100%<200%.

[0070] In one preferred embodiment of the present invention, more than 90% of the gold in the nanogold has a valence of zero.

[0071] In the present invention, the valence of the nanogold is measured by an X-ray photoelectron spectrometer (XPS). The measured XPS peak is divided by software to obtain small peaks corresponding to zero-valent, +1-valent, and +3-valent Au, and the proportion of the peak area corresponding to zero-valent Au to the total peak area is calculated to obtain the content of zero-valent nanogold in the nanogold.

[0072] In one preferred embodiment of the present invention, the difference in the number of Au particles within any 50 nm x 50 nm area on the catalyst is 30% or less.

[0073] In the present invention, the difference in the number of Au particles within any 50nm x 50nm region on the catalyst being 30% or less means that, in an HAADF-STEM photograph of a single nanogold-loaded titanium silicon molecular sieve particle, the nanogold-loaded titanium silicon molecular sieve is divided into multiple (three or more) adjacent 50nm x 50nm regions, the number of Au particles in each 50nm x 50nm region is calculated, and the region with the most Au particles is designated region A1 and the region with the least Au particles is designated region A2, where (number of Au particles in region A1 - number of Au particles in region A2) / number of Au particles in region A1 is ≦30%.

[0074] In one preferred embodiment of the present invention, the number of Au particles within any 50 nm×50 nm area of ​​the catalyst is 5 to 40.

[0075] In the present invention, the number of Au particles in any 50 nm × 50 nm region of the catalyst being 5 to 40 means that in a HAADF-STEM photograph of a single nanogold-loaded titanium silicon molecular sieve particle, the nanogold-loaded titanium silicon molecular sieve is divided into multiple (three or more) adjacent 50 nm × 50 nm regions, and the number of Au particles in each 50 nm × 50 nm region is 5 to 40.

[0076] In one preferred embodiment of the present invention, the Au particles have a particle size of 0.1 to 5 nm.

[0077] In the present invention, the particle size of the Au particles is observed using a high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM), and the number of the Au particles within a 50 nm × 50 nm area is measured using the high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM).

[0078] In one preferred embodiment of the present invention, the molar ratio of titanium to silicon in the catalyst is 0.001-0.04:1, preferably 0.005-0.025:1.

[0079] In one preferred embodiment of the present invention, based on the total amount of the catalyst, the content of the nanogold is 0.01 wt% to 1 wt%, preferably 0.04 wt% to 0.8 wt%, more preferably 0.04 wt% to 0.5 wt%.

[0080] The third aspect of the present invention includes the steps of: treating a titanium silicon molecular sieve with an aqueous aliphatic amine solution, and then supporting nanogold to obtain the catalyst; The titanium silicon molecular sieve is the titanium silicon molecular sieve according to the first embodiment, and the method for preparing the nanogold-supported titanium silicon molecular sieve catalyst is also provided.

[0081] In one preferred embodiment of the invention, the method comprises: (1) mixing titanium silicon molecular sieve with an aqueous aliphatic amine solution and filtering the mixture to obtain an alkali-post-treated titanium silicon molecular sieve; (2) mixing the alkali-treated titanium silicon molecular sieve with an aqueous solution containing a gold compound, and adjusting the pH of the resulting mixture to 7-9 to obtain a suspension; (3) filtering the suspension and activating the resulting filter cake to obtain the catalyst; The titanium silicon molecular sieve is the titanium silicon molecular sieve according to the first embodiment.

[0082] In one preferred embodiment of the present invention, in step (1), the aliphatic amine is at least one selected from ethylamine, n-propylamine, ethylenediamine, n-butylamine, di-n-propylamine, butanediamine, and hexamethylenediamine.

[0083] In a preferred embodiment of the present invention, in step (1), the molar ratio of the titanium silicon molecular sieve, the aliphatic amine in the aqueous aliphatic amine solution, and the water in the aqueous aliphatic amine solution is 1:(0.01-1):2-20, in terms of SiO2 of the titanium silicon molecular sieve.

[0084] In one preferred embodiment of the present invention, in step (1), the mixing is carried out at a temperature of 80 to 250° C. for a time of 10 to 120 minutes.

[0085] In the present invention, the titanium-silicon molecular sieve is alkali-treated with an aliphatic amine aqueous solution, which generates many hydroxyl defects on the titanium-silicon molecular sieve, making it easier for more Au nanoparticles to be uniformly fixed on the titanium-silicon molecular sieve. This promotes the dispersion of Au on the titanium-silicon molecular sieve, improves the synthesis efficiency of the oxidant in the hydro-oxidation reaction, and ultimately enhances the reaction efficiency. On the other hand, the electron-inducing effect of the framework titanium atoms on the molecular sieve is uniformly applied to the Au nanoparticles, which tend to convert to zero-valent Au upon activation. Zero-valent Au can effectively catalyze the in-situ generation of H2O2 oxidant from hydrogen gas and oxygen gas, improving product selectivity.

[0086] In one preferred embodiment of the present invention, the gold compound-containing aqueous solution is selected from an aqueous chloroauric acid solution.

[0087] In one preferred embodiment of the present invention, the concentration of the aqueous chloroauric acid solution is 0.0001 to 0.1M, preferably 0.0005 to 0.05M, and more preferably 0.005 to 0.05M.

[0088] In the present invention, if the amount of chloroauric acid used is too large, the nanogold particles will aggregate, causing side reactions during the reaction and reducing product selectivity. If the amount of chloroauric acid used is too small, the activity of the nanogold-supported titanium silicon molecular sieve catalyst produced will decrease. Under preferred conditions, the amount of the chloroauric acid solution used, calculated as gold, is 0.01 wt% to 5 wt%, preferably 0.1 wt% to 5 wt%, of the alkali-post-treated titanium silicon molecular sieve.

[0089] In one preferred embodiment of the present invention, the pH adjuster used to adjust the pH of the resulting mixture in step (2) is at least one selected from sodium hydroxide, potassium hydroxide, cesium hydroxide, urea, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, cesium carbonate, and cesium bicarbonate.

[0090] In one preferred embodiment of the present invention, step (2) may be to mix the alkali-post-treated titanium silicon molecular sieve with a gold compound-containing aqueous solution, add a weak alkaline pH adjuster, heat-treat the resulting mixture until the pH of the mixture reaches 5-6, and then add a strong alkaline pH adjuster to adjust the pH to 7-9 to obtain a suspension.

[0091] In the present invention, since the chloroauric acid aqueous solution is highly acidic, a weakly alkaline pH adjuster is first added to slowly adjust the pH of the chloroauric acid solution and reduce the concentration gradient. Then, a strongly alkaline pH adjuster is used to quickly adjust the pH of the resulting mixture to the desired range, thereby preventing the aggregation of Au into large particles, thereby avoiding side reactions catalyzed by large Au particles and improving product selectivity.

[0092] In the present invention, in step (2), the heat treatment increases the hydrolysis rate of the weak alkali, thereby avoiding the production efficiency being too low due to the hydrolysis being too slow.

[0093] In one preferred embodiment of the present invention, in step (2), the weakly alkaline pH adjuster is at least one selected from urea, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, cesium carbonate, and cesium bicarbonate.

[0094] In one preferred embodiment of the present invention, in step (2), the strongly alkaline pH adjuster is at least one selected from sodium hydroxide, potassium hydroxide, and cesium hydroxide.

[0095] In one preferred embodiment of the present invention, in step (2), the temperature of the heat treatment is 50 to 95°C.

[0096] In one preferred embodiment of the present invention, in step (3), the activation conditions are a temperature of 150 to 500°C and a time of 1 to 5 hours, and the activation gas is a mixed gas of nitrogen gas and any one selected from oxygen gas, hydrogen gas, and propylene, or a mixed gas of hydrogen gas, propylene, and nitrogen gas, and preferably the activation gas is a mixed gas of hydrogen gas and nitrogen gas.

[0097] A fourth aspect of the present invention provides a nanogold-supported titanium silicon molecular sieve catalyst produced by the method according to the third aspect.

[0098] In one preferred embodiment of the present invention, the catalyst comprises a titanium silicon molecular sieve support and nanogold supported on the support, and has a micropore volume of 0.06 to 0.4 cm. 3 / g, micropore specific surface area is 160~450m 2 / g, mesopore volume 0.05-0.08 cm 3 / g, mesopore specific surface area is 40-85m 2 / g, and the particle size is 100 to 250 nm.

[0099] In one preferred embodiment of the present invention, the catalyst has a micropore volume of 0.1 to 0.3 cm 3 / g, micropore specific surface area is 260~410m 2 / g, mesopore volume 0.058-0.078 cm 3 / g, mesopore specific surface area is 45-80m 2 / g, and the particle size is 150 to 210 nm.

[0100] In one preferred embodiment of the present invention, in the catalyst, 130%<surface Ti / Si (mol %) / bulk phase Ti / Si (mol %)×100%<220%.

[0101] In one preferred embodiment of the present invention, in the catalyst, 145%<surface Ti / Si (mol %) / bulk phase Ti / Si (mol %)×100%<200%.

[0102] In one preferred embodiment of the present invention, more than 90% of the gold in the nanogold has a valence of zero.

[0103] In one preferred embodiment of the present invention, the difference in the number of Au particles within any 50 nm x 50 nm area on the catalyst is 30% or less.

[0104] In one preferred embodiment of the present invention, the number of Au particles within any 50 nm×50 nm area of ​​the catalyst is 5 to 40.

[0105] In one preferred embodiment of the present invention, the Au particles have a particle size of 0.1 to 5 nm.

[0106] In one preferred embodiment of the present invention, the molar ratio of titanium to silicon in the catalyst is 0.001-0.04:1, preferably 0.005-0.025:1.

[0107] In one preferred embodiment of the present invention, based on the total amount of the catalyst, the content of the nanogold is 0.01 wt% to 1 wt%, preferably 0.04 wt% to 0.8 wt%, more preferably 0.04 wt% to 0.5 wt%.

[0108] A fifth aspect of the present invention provides use of the nanogold-supported titanium silicon molecular sieve catalyst according to the second or fourth aspect in olefin epoxidation, cycloolefin epoxidation, phenol hydroxylation, and cyclohexanone ammonia ammoximation.

[0109] In one preferred embodiment of the present invention, the olefin epoxidation reaction is a propylene vapor phase epoxidation reaction.

[0110] In one preferred embodiment of the present invention, the olefin epoxidation reaction is a propylene gas phase epoxidation reaction: The method comprises mixing and reacting hydrogen gas, oxygen gas, and propylene under the protection of an inert gas and in the presence of a catalyst to obtain propylene oxide, wherein the catalyst is the nanogold-supported titanium silicon molecular sieve described in the second and fourth embodiments.

[0111] According to the present invention, the reaction is preferably carried out under the following conditions: the volumetric flow ratio of hydrogen gas, oxygen gas, and propylene is 0.5-2:0.5-2:1, and more preferably, the volumetric flow ratio of propylene and inert gas is 1:1-10.

[0112] In some preferred embodiments of the present invention, the reaction conditions also include a temperature of 120 to 220° C. and a pressure of 0.1 to 0.5 MPa.

[0113] In the present invention, the reaction scheme of propylene vapor-phase epoxidation is shown in Figure 1. As can be seen from Figure 1, Au catalyzes the production of H2O2 from H2 and O2, and then H2O2 and TS-1 form Ti-OOH active sites, and Ti-OOH catalyzes the production of propylene oxide from propylene.

[0114] In the present invention, the propylene gas phase epoxidation method may be a continuous operation method. Specifically, after the catalyst is charged into a reactor, a mixed gas of hydrogen gas, oxygen gas, propylene, and an inert gas is continuously added to carry out the reaction.

[0115] In the present invention, the form of the catalyst is not particularly limited, and the catalyst may be a nanogold-supported titanium silicon molecular sieve powder, which may be supported on a carrier and used, and a person skilled in the art may select the form according to the type of reactor.

[0116] In the present invention, the separation of the propylene gas phase epoxidation product and the catalyst can be adjusted according to the catalyst form and actual needs. For example, when the catalyst is nanogold-supported titanium silicon molecular sieve powder, the separation of the product and the recovery and reuse of the catalyst can be achieved by sedimentation, filtration, centrifugation, evaporation, membrane separation, etc. When the catalyst is nanogold-supported titanium silicon molecular sieve (molded catalyst) supported on a carrier, the molded catalyst can be loaded into a fixed-bed reactor and the catalyst can be recovered after the reaction is completed.

[0117] The present invention will be described in more detail below with reference to examples. In the following examples, room temperature refers to 25±5°C.

[0118] Unless otherwise specified, the materials used in the following examples are chemically pure reagents.

[0119] In the following examples and comparative examples, the micropore specific surface area and micropore volume were calculated by measuring the static N adsorption / desorption curve of the sample at liquid nitrogen temperature using a Micromeritics ASAP 2460 static nitrogen adsorption apparatus, and then analyzing it using the t-plot method.

[0120] The mesopore specific surface area and mesopore volume were calculated by measuring the static N2 adsorption / desorption curve of the sample at liquid nitrogen temperature using a Micro Meretics ASAP 2460 static nitrogen adsorption apparatus, and then analyzing it using the BJH method.

[0121] The total specific surface area is measured by the BET method.

[0122] The pore size distribution diagram is calculated using the BJH formula.

[0123] The micropore size distribution diagram is calculated by the t-plot method.

[0124] The particle size is observed by high angle annular dark field scanning transmission electron microscope (HAADF-STEM).

[0125] The titanium content and silicon content of the surface are measured by an X-ray photoelectron spectroscopy (XPS).

[0126] The titanium and silicon contents of the bulk phase are measured by X-ray fluorescence (XRF) analysis.

[0127] The valence of nanogold is measured using an X-ray photoelectron spectrometer (XPS). The measured XPS peaks are split using software to obtain small peaks corresponding to zero-valent, +1-valent, and +3-valent Au. The proportion of the peak area corresponding to zero-valent Au to the total peak area is calculated to determine the content of zero-valent nanogold in the nanogold.

[0128] The number of Au particles within a 50 nm × 50 nm area on the titanium silicon molecular sieve is measured by high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM).

[0129] In the following production examples, the specific chemical structural formulas of the silanizing reagents used are shown in Table 1, and the corresponding substituents and parameters in formula (I) are also shown in Table 1. Compounds 1 to 6 are all commercially available products.

[0130] [Table 1]

[0131] Preparation Examples 1 to 9 illustrate the preparation of titanium silicon molecular sieves.

[0132] Manufacturing Example 1 (1) Tetraethyl silicate, tetrapropylammonium hydroxide, and water were mixed at room temperature with a first stirring and mixing cycle to obtain a mixed system. While stirring, a mixture of tetrabutyl titanate and isopropyl alcohol was added dropwise to the mixed system at a rate of 0.2 mL / min, and a second stirring cycle was performed for 0.5 hours to obtain a mixed solution. When tetraethyl silicate is calculated as SiO2, tetrapropylammonium hydroxide is calculated as N, and tetrabutyl titanate is calculated as TiO2, the molar ratio of tetraethyl silicate, tetrapropylammonium hydroxide, and water was 1:0.1:15, and the molar ratio of tetraethyl silicate, tetrabutyl titanate, and isopropyl alcohol was 1:0.015:3.

[0133] Next, the alcohol was removed from the mixed solution at 70°C for 8 hours to obtain titanium silicon sol.

[0134] (2) Compound (1) was added to the titanium silicon sol, and the mixture was stirred at room temperature for 1.5 hours to obtain a mixture. The molar ratio of compound (1) to tetraethyl silicate was 0.1:1.

[0135] (3) The mixture was heated to 170°C over 0.5 hours and subjected to hydrothermal crystallization at 170°C for 24 hours to obtain a crystallized product. The crystallized product was rinsed with water, filtered, and then dried at 120°C for 2 hours.

[0136] The dried product was roasted at 550°C for 6h to obtain titanium silicon molecular sieve TS-1-1.

[0137] The physical properties of the titanium silicon molecular sieve TS-1-1 obtained in this preparation are shown in Table 2. The micropore size distribution and micropore size distribution of the titanium silicon molecular sieve TS-1-1 are shown in Figures 2 and 3, respectively. As can be seen from Figure 2, the TS-1-1 molecular sieve has many micropores of about 0.55 nm. As can be seen from Figure 3, the TS-1-1 molecular sieve has almost no mesopore channels.

[0138] Manufacturing Example 2 Titanium silicon molecular sieve was prepared according to the method of Preparation Example 1, except that in step (2), compound (1) was replaced with compound (2). The physical properties of the prepared titanium silicon molecular sieve TS-1-2 are shown in Table 2.

[0139] Manufacturing Example 3 The titanium silicon molecular sieve was prepared according to the method of Preparation Example 1, except that in step (2), compound (1) was replaced with compound (3). The physical properties of the prepared titanium silicon molecular sieve TS-1-3 are shown in Table 2.

[0140] Manufacturing Example 4 Titanium silicon molecular sieve was prepared according to the method of Preparation Example 1, except that in step (2), compound (1) was replaced with compound (4). The physical properties of the prepared titanium silicon molecular sieve TS-1-4 are shown in Table 2.

[0141] Manufacturing Example 5 Titanium silicon molecular sieve was prepared according to the method of Preparation Example 1, except that in step (2), compound (1) was replaced with compound (5). The physical properties of the prepared titanium silicon molecular sieve TS-1-5 are shown in Table 2.

[0142] Manufacturing Example 6 Titanium silicon molecular sieve was prepared according to the method of Preparation Example 1, except that in step (2), compound (1) was replaced with compound (6). The physical properties of the prepared titanium silicon molecular sieve TS-1-6 are shown in Table 2.

[0143] Manufacturing Example 7 (1) Tetraethyl silicate, tetrapropylammonium hydroxide, and water were mixed at room temperature with a first stirring and mixing cycle to obtain a mixed system. While stirring, a mixture of tetrabutyl titanate and isopropyl alcohol was added dropwise to the mixed system at a rate of 0.2 mL / min, and a second stirring cycle was performed for 0.5 hours to obtain a mixed solution. When tetraethyl silicate is calculated as SiO2, tetrapropylammonium hydroxide is calculated as N, and tetrabutyl titanate is calculated as TiO2, the molar ratio of tetraethyl silicate, tetrapropylammonium hydroxide, and water was 1:0.1:15, and the molar ratio of tetraethyl silicate, tetrabutyl titanate, and isopropyl alcohol was 1:0.015:3.

[0144] Next, the alcohol was removed from the mixed solution at 70°C for 8 hours to obtain titanium silicon sol.

[0145] (2) The mixture was heated from room temperature to 170°C at a rate of 1°C / min and subjected to hydrothermal crystallization at 170°C for 72 hours to obtain a crystallized product. The crystallized product was rinsed with water, filtered, and then dried at 120°C for 2 hours.

[0146] The dried product was roasted at 550°C for 6h to obtain titanium silicon molecular sieve TS-1-7.

[0147] The physical properties of the titanium silicon molecular sieve TS-1-7 obtained in this preparation are shown in Table 2, and the micropore size distribution of the titanium silicon molecular sieve TS-1-7 is shown in Figure 2. As can be seen from Figure 2, the TS-1-7 obtained without adding the silanizing reagent of the present invention also has micropore channels with a pore size of about 0.55 nm, but its micropore content is much lower than that of the TS-1-1 molecular sieve.

[0148] Manufacturing Example 8 (1) 31.0 g of tetraethyl silicate, 1.8 g of tetrabutyl titanate, and 15 g of tetrapropylammonium hydroxide solution (mass concentration 24.4%) were mixed, and 25 g of deionized water was added with stirring. Hydrolysis was carried out at a temperature of 80°C, and the alcohol was removed for 4 hours while the evaporated water was replenished, yielding a pale yellow, transparent aqueous solution.

[0149] (2) The product obtained in step (1) was placed in a stainless steel sealed reaction vessel and allowed to stand at 80°C for 24 hours to obtain a pre-crystallized product.

[0150] [ka]

[0151] 2.0 g of compound represented by formula (II) was added to the above pre-crystallized product and stirred at room temperature for 2 hours to form a transparent viscous liquid. The liquid was transferred to a stainless steel sealed reactor and kept at 90°C for 12 hours, then slowly heated to 165°C at a rate of 1°C / min and kept at this temperature for 2 days. The liquid was then filtered, washed, dried at 120°C for 12 hours, and calcined at 550°C for 6 hours to obtain titanium silicon molecular sieve TS-1-8.

[0152] The physical properties of the titanium silicon molecular sieve TS-1-8 obtained in this preparation are shown in Table 2, and the pore size distribution of the titanium silicon molecular sieve TS-1-8 is shown in Figure 3. As can be seen from Figure 3, TS-1-8 contains micropore channels with a pore size of 2 nm and abundant mesopore channels with a pore size of about 38 nm. Therefore, although its micropore specific surface area is not small, the proportion of the micropore specific surface area to the total specific surface area is low.

[0153] Manufacturing Example 9 (1) 31.0 g of tetraethyl silicate, 1.8 g of tetrabutyl titanate, and 15 g of tetrapropylammonium hydroxide solution (mass concentration 24.4%) were mixed, and 25 g of deionized water was added with stirring. Hydrolysis was carried out at a temperature of 80°C, and the alcohol was removed for 4 hours while the evaporated water was replenished, yielding a pale yellow, transparent aqueous solution.

[0154] (2) The product obtained in step (1) was placed in a stainless steel sealed reaction vessel and allowed to stand at 80°C for 24 hours to obtain a pre-crystallized product.

[0155] [ka]

[0156] 2.0 g of the compound represented by formula (III) was added to the above pre-crystallized product and stirred at room temperature for 2 hours to form a transparent viscous liquid. The liquid was transferred to a stainless steel sealed reactor and kept at 90°C for 12 hours, then slowly heated to 165°C at a rate of 1°C / min and kept at this temperature for 2 days. The liquid was then filtered, washed, dried at 120°C for 12 hours, and roasted at 550°C for 6 hours to obtain titanium silicon molecular sieve TS-1-9.

[0157] The physical properties of the titanium silicon molecular sieve TS-1-9 obtained in this production example are shown in Table 2.

[0158] [Table 2]

[0159] Example 1 (1) Titanium silicon molecular sieve TS-1-1 was mixed with an ethylamine aqueous solution and subjected to high-temperature treatment to obtain a first suspension, which was then filtered and post-treated with alkali to obtain a titanium silicon molecular sieve. The molar ratio of the titanium silicon molecular sieve, ethylamine in the ethylamine aqueous solution, and water in the ethylamine aqueous solution was 1:0.5:10, calculated as SiO2 of the titanium silicon molecular sieve. The high-temperature treatment was performed at 120°C for 60 minutes.

[0160] (2) 5 g of the alkali-post-treated titanium silicon molecular sieve TS-1-1 was mixed with 100 mL of an aqueous solution (0.01 M) of chloroauric acid (HAuCl4), and NaOH was added to adjust the pH of the resulting mixture to 8 to obtain a second suspension.

[0161] (3) The second suspension was filtered, and the resulting filter cake was activated to obtain nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-1.

[0162] Here, the activation conditions are a temperature of 200° C., a time of 3 hours, and an activation gas of a mixed gas of hydrogen gas and nitrogen gas (volume ratio of 1:7).

[0163] The physical properties of the nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-1 are shown in Table 3.

[0164] Example 2 Nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-2 was obtained according to the method of Example 1, except that titanium silicon molecular sieve TS-1-1 in step (1) was replaced with titanium silicon molecular sieve TS-1-2. The physical properties of the nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-2 are listed in Table 3.

[0165] Example 3 Nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-3 was obtained by following the method of Example 1, except that titanium silicon molecular sieve TS-1-1 in step (1) was replaced with titanium silicon molecular sieve TS-1-3. The physical properties of the nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-3 are listed in Table 3, and the HAADF-STEM image of the catalyst Au / TS-1-3 is shown in Figure 4. As can be seen from Figure 4, the Au nanoparticles on the Au / TS-1-3 catalyst are uniform in size (about 2.4 nm) and uniformly dispersed on the titanium silicon molecular sieve TS-1-3.

[0166] Example 4 The nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-4 was obtained according to the method of Example 1, except that the titanium silicon molecular sieve TS-1-1 in step (1) was replaced with titanium silicon molecular sieve TS-1-4. The physical properties of the nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-4 are shown in Table 3.

[0167] Example 5 Nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-5 was obtained according to the method of Example 1, except that titanium silicon molecular sieve TS-1-1 in step (1) was replaced with titanium silicon molecular sieve TS-1-5. The physical properties of the nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-5 are listed in Table 3.

[0168] Example 6 Nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-6 was obtained according to the method of Example 1, except that titanium silicon molecular sieve TS-1-1 in step (1) was replaced with titanium silicon molecular sieve TS-1-6. The physical properties of the nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-6 are listed in Table 3.

[0169] Example 7 In step (2), 5 g of the alkali-treated titanium silicon molecular sieve TS-1-1 was mixed with 100 mL of a 0.01 M aqueous solution of chloroauric acid (HAuCl), urea was added, and the mixture was heated at 70°C until the pH reached 6. NaOH was then added to adjust the pH to 8 to obtain a second suspension. The nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-1-1 was obtained according to the method of Example 1. The physical properties of the nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-1-1 are shown in Table 3.

[0170] Example 8 In step (2), 5 g of the alkali-treated titanium silicon molecular sieve TS-1-3 was mixed with 100 mL of a 0.01 M aqueous solution of chloroauric acid (HAuCl), urea was added, and the resulting mixture was heated at 70°C until the pH reached 6. NaOH was then added to adjust the pH to 8 to obtain a second suspension. The nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-3-1 was obtained according to the method of Example 3. The physical properties of the nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-3-1 are shown in Table 3.

[0171] Example 9 The alkaline post-treatment step (1) was omitted. 5 g of titanium silicon molecular sieve TS-1-1 was mixed with 100 mL of an aqueous solution of chloroauric acid (HAuCl4) (0.01 M), and NaOH was added to adjust the pH of the resulting mixture to 8 to obtain a second suspension. The second suspension was filtered, and the nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-1-2 was obtained according to the method of Example 1, except that the obtained filter cake was activated.

[0172] The physical properties of the nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-1-2 are shown in Table 3.

[0173] Example 10 The alkaline post-treatment step (1) was omitted. 5 g of titanium silicon molecular sieve TS-1-3 was mixed with 100 mL of an aqueous solution of chloroauric acid (HAuCl4) (0.01 M), and NaOH was added to adjust the pH of the resulting mixture to 8 to obtain a second suspension. The second suspension was filtered, and the nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-3-2 was obtained according to the method of Example 3, except that the obtained filter cake was activated.

[0174] The physical properties of the nanogold-loaded titanium silicon molecular sieve catalyst Au / TS-1-3-2 are shown in Table 3. The HAADF-STEM image of the catalyst Au / TS-1-3-2 is shown in Figure 5. As can be seen from Figure 5, the Au nanoparticles are slightly large in size (about 3.8 nm) and have an uneven distribution in the titanium silicon molecular sieve TS-1-3-2.

[0175] Example 11 The alkaline post-treatment step (1) was omitted. 5 g of titanium silicon molecular sieve TS-1-5 was mixed with 100 mL of an aqueous solution of chloroauric acid (HAuCl4) (0.01 M), and NaOH was added to adjust the pH of the resulting mixture to 8 to obtain a second suspension. The second suspension was filtered, and the nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-5-1 was obtained according to the method of Example 5, except that the obtained filter cake was activated.

[0176] The physical properties of the nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-5-1 are shown in Table 3.

[0177] Comparative Example 1 Nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-7 was obtained according to the method of Example 1, except that titanium silicon molecular sieve TS-1-1 in step (1) was replaced with titanium silicon molecular sieve TS-1-7. The physical properties of the nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-7 are listed in Table 3.

[0178] Comparative Example 2 Nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-8 was obtained according to the method of Example 1, except that titanium silicon molecular sieve TS-1-1 in step (1) was replaced with titanium silicon molecular sieve TS-1-8. The physical properties of the nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-8 are shown in Table 3.

[0179] Comparative Example 3 The nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-9 was obtained according to the method of Example 1, except that the titanium silicon molecular sieve TS-1-1 in step (1) was replaced with titanium silicon molecular sieve TS-1-9. The physical properties of the nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-9 are shown in Table 3.

[0180] [Table 3]

[0181] Measurement example The nanogold-loaded titanium silicon molecular sieves prepared in Examples 1-11 and Comparative Examples 1-3 were used as catalysts. The catalysts were placed in a tubular reactor with an inner diameter of 8 mm, heated to 180°C in a N2 atmosphere, and hydrogen gas, oxygen gas, and propylene were introduced to initiate the reaction. After 1 hour of reaction, the product was analyzed online. The catalyst loading was 0.4 g. The gas flow rates, reaction temperatures, and pressures are shown in Table 4, and the catalytic reaction results are shown in Table 5.

[0182] In the present invention, the reactants and products in the evaluation system were analyzed by gas chromatography, using an Agilent-6890 chromatograph, molecular sieve 5A and PoraBONDU chromatography columns, and FID and TCD detectors.

[0183] Propylene conversion % = (moles of propylene in raw material - moles of propylene in product) / moles of propylene in raw material × 100% Propylene oxide selectivity % = moles of propylene oxide in the product / (moles of propylene in the feed - moles of propylene in the product) x 100%

[0184] [Table 4]

[0185] [Table 5]

[0186] Comparison of Measurement Examples 1 to 11 and Measurement Examples 12 to 14 shows that by combining the silanizing reagent of the present invention with specific crystallization conditions, titanium silicon molecular sieves with larger micropore volume, micropore specific surface area, and the ratio of micropore specific surface area to total specific surface area can be obtained. Furthermore, the obtained titanium silicon molecular sieves have a high surface titanium content, which can improve the propylene conversion rate and propylene oxide selectivity.

[0187] As can be seen from the comparison of Measurement Examples 1 to 8 and Measurement Examples 9 to 11, by post-treating the titanium silicon molecular sieve with alkali before loading, the dispersibility of the gold particles and the content of zero-valent gold are improved, and the propylene conversion rate and the selectivity for propylene oxide are further improved.

[0188] As can be seen from the comparison of Measurement Examples 1 to 6 and Measurement Examples 7 to 8, by gradually adjusting the pH during nanogold loading, it is possible to effectively prevent Au from agglomerating into large particles, and further improve the propylene conversion rate and propylene oxide selectivity.

[0189] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, including combining each technical feature in other appropriate ways, and these simple modifications and combinations should also be considered as the content disclosed in the present invention, and all fall within the protection scope of the present invention.

Claims

1. Micropore specific surface area is 320 to 500 m ２ / g, micropore volume of 0.1 to 0.4 cm ３ / g, mesopore specific surface area is 50 to 100 m ２ / g, mesopore volume is 0.075 to 0.1 cm ３ / g, particle diameter is 100-250 nm, and the ratio of the micropore specific surface area to the total specific surface area is 50%-90%.

2. Micropore specific surface area is 350 to 480 m ２ / g, micropore volume of 0.13 to 0.37 cm ３ / g, mesopore specific surface area is 70 to 100 m ２ / g, mesopore volume is 0.08 to 0.1 cm ３ / g, particle diameter is 150 to 210 nm, and the ratio of the micropore specific surface area to the total specific surface area is 60% to 90%.

3. 2. The molecular sieve according to claim 1, wherein in the titanium silicon molecular sieve, 130%<surface Ti / Si (mol%) / bulk phase Ti / Si (mol%)×100%<220%.

4. 4. The molecular sieve according to claim 3, wherein in the titanium silicon molecular sieve, 145%<surface Ti / Si (mol%) / bulk phase Ti / Si (mol%)×100%<200%.

5. 2. The molecular sieve of claim 1, wherein the molar ratio of titanium to silicon is 0.001-0.04:1, preferably 0.005-0.025:

1.

6. A catalyst for use in an olefin epoxidation reaction, a cycloolefin epoxidation reaction, a phenol hydroxylation reaction, or a cyclohexanone ammonia ammoximation reaction, comprising: A titanium silicon molecular sieve support and nanogold supported on the support, Micropore volume of 0.06 to 0.4 cm ３ / g, micropore specific surface area is 160 to 450 m ２ / g, mesopore volume is 0.05 to 0.08 cm ３ / g, mesopore specific surface area is 40 to 85 m ２ / g and a particle size of 100 to 250 nm.

7. Micropore volume of 0.1 to 0.3 cm ３ / g, micropore specific surface area is 260 to 410 m ２ / g, mesopore volume is 0.058 to 0.078 cm ３ / g, mesopore specific surface area is 45 to 80 m ２ / g, and the particle size is 150 to 210 nm.

8. 7. The catalyst of claim 6, wherein in the catalyst, 130%<surface Ti / Si (mol%) / bulk phase Ti / Si (mol%) x 100%<220%.

9. 9. The catalyst of claim 8, wherein in the catalyst, 145%<surface Ti / Si (mol %) / bulk phase Ti / Si (mol %) x 100%<200%.

10. 7. The catalyst of claim 6, wherein more than 90% of the gold in the nanogold has a valence of zero.

11. 7. The catalyst according to claim 6, wherein the difference in the number of Au particles within any 50 nm x 50 nm area of ​​the catalyst is 30% or less.

12. the number of Au particles within any 50 nm × 50 nm area of ​​the catalyst is 5 to 40; The catalyst according to claim 6, wherein the particle diameter of the Au particles is preferably 0.1 to 5 nm.

13. 7. The catalyst of claim 6, wherein the molar ratio of titanium to silicon is 0.001-0.04:1, preferably 0.005-0.025:

1.

14. 7. The catalyst of claim 6, wherein the content of the nanogold is 0.01 wt% to 1 wt%, preferably 0.04 wt% to 0.8 wt%, more preferably 0.04 wt% to 0.5 wt%, based on the total amount of the catalyst.

15. A method for producing a nanogold-supported titanium silicon molecular sieve catalyst for use in olefin epoxidation reaction, cycloolefin epoxidation reaction, phenol hydroxylation reaction, and cyclohexanone ammonia ammoximation reaction, comprising the steps of: The method includes the steps of: treating titanium silicon molecular sieve with an aqueous aliphatic amine solution to form an alkali; and then supporting nanogold on the titanium silicon molecular sieve to obtain the catalyst; The method, wherein the titanium silicon molecular sieve is the titanium silicon molecular sieve according to any one of claims 1 to 5.

16. (1) mixing titanium silicon molecular sieve with an aqueous aliphatic amine solution and filtering the mixture to obtain an alkali-post-treated titanium silicon molecular sieve; (2) mixing the alkali-treated titanium silicon molecular sieve with an aqueous solution containing a gold compound, and then adjusting the pH of the resulting mixture to 7-9 to obtain a suspension; and (3) filtering the suspension and activating the resulting filter cake to obtain the catalyst.

17. In step (1), the aliphatic amine is at least one selected from ethylamine, n-propylamine, ethylenediamine, n-butylamine, di-n-propylamine, butanediamine, and hexamethylenediamine; The SiO of the titanium silicon molecular sieve ２ In terms of conversion, the molar ratio of the titanium silicon molecular sieve, the aliphatic amine in the aliphatic amine aqueous solution, and the water in the aliphatic amine aqueous solution is 1:(0.01-1):2-20; Preferably, in step (1), the mixing is performed at a temperature of 80 to 250°C for a time of 10 to 120 minutes; Preferably, in step (2), the gold compound-containing aqueous solution is selected from an aqueous chloroauric acid solution; the concentration of the aqueous chloroauric acid solution is 0.0001 to 0.1 M, preferably 0.0005 to 0.05 M, and more preferably 0.005 to 0.05 M; 16. The method of claim 15, wherein the amount of the chloroauric acid aqueous solution used is 0.01 wt % to 5 wt %, preferably 0.1 wt % to 5 wt %, based on the weight of the alkali-post-treated titanium silicon molecular sieve, in terms of gold content of the chloroauric acid aqueous solution.

18. In step (2), the alkali-post-treated titanium silicon molecular sieve is mixed with a gold compound-containing aqueous solution, and a weak alkaline pH adjuster is added. The resulting mixture is heated to a pH of 5-6, and then a strong alkaline pH adjuster is added to adjust the pH to 7-9 to obtain a suspension. The method according to claim 15, wherein the temperature of the heat treatment is preferably 50 to 95°C.

19. Use of the nanogold-supported titanium silicon molecular sieve catalyst according to any one of claims 6 to 14 in olefin epoxidation reaction, cycloolefin epoxidation reaction, phenol hydroxylation reaction, or cyclohexanone ammonia ammoximation reaction, Preferably, the olefin epoxidation reaction is a propylene gas phase epoxidation reaction.

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