Titanium silicon molecular sieve, nanogold supported titanium silicon molecular sieve catalyst, and its preparation 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 sieve, nanogold supported titanium silicon molecular sieve catalyst, and the preparation method and use thereof. [Background technology]

[0005] Heteroatomic molecular sieves have a regular topological structure, and the introduction of framework metal atoms brings about unique acidic properties, making them 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 replace a small number of framework silicon atoms in an all-silicon MFI structure molecular sieve, that is, titanium atoms are embedded in the framework positions of the molecular sieve in the form of four-coordinated coordination. Since framework titanium species have Lewis acidity, their vacant orbitals can accept extranuclear electrons from oxygen atoms in H2O2 molecules. Therefore, TS-1 molecular sieves can efficiently activate H2O2 molecules and organics with various functional groups to carry out selective oxidation reactions such as olefin epoxidation, cycloolefin epoxidation, phenol hydroxylation, and cyclohexanone ammoximation. Compared with traditional oxidation processes, the H2O2 / TS-1 catalytic oxidation process has the advantages of mild reaction conditions and environmentally friendly and efficient processes.

[0006] At present, the H2O2 / TS-1 catalytic oxidation system has several industrial equipment such as propylene epoxidation (HPPO) and cyclohexanone ammoximation. Although this catalytic system has many advantages, it requires the installation of hydrogen peroxide production equipment, so there are still some challenges to its popularization. The storage and transportation conditions of hydrogen peroxide are strict, and it is necessary to equip on-site production equipment, which limits the process layout. In addition, high-concentration hydrogen peroxide is difficult to prepare and has storage safety problems. In order to fundamentally alleviate this limitation, researchers have considered directly catalyzing the selective oxidation reaction of organic matter under a hydrogen (H2) and oxygen (O2) atmosphere. Gas-phase selective oxidation technology makes the industrial layout more flexible and meets the development needs of 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, its preparation method, nanogold supported titanium silicon molecular sieve catalyst, and its preparation method and use, in order to solve the problems of low micropore volume and low specific surface area of ​​micropores in the TS-1 molecular sieve carrier 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 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 The present invention provides a titanium silicon molecular sieve having a particle size of 100 to 250 nm and a ratio of a micropore specific surface area to a total specific surface area of ​​50% to 90%.

[0010] A second aspect of the present invention is A titanium silicon molecular sieve support and nanogold supported on the support, 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 is 0.05-0.08 cm 3 / g, mesopore specific surface area is 40-85m 2 The present invention provides a nanogold-supported titanium silicon molecular sieve catalyst having a particle size of 100 to 250 nm.

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

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

[0014] According to the above technical solution, the present invention supports nanogold particles on titanium silicon molecular sieve with specific physical property parameters, so that the nanogold in the obtained nanogold-supported titanium silicon molecular sieve catalyst has high dispersibility. When this catalyst is used in propylene gas phase epoxidation reaction, it has high catalytic activity, propylene conversion rate is improved to 8%-14%, and propylene oxide selectivity is improved to 90%-99%. [Brief description of the drawings]

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

[0016] The range endpoints 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 the 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 obtain 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 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 The present invention provides a titanium silicon molecular sieve having a particle size of 100 to 250 nm and a ratio of a micropore specific surface area to a total specific surface area of ​​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 measured by using Micromeritics ASAP 2460 type static nitrogen adsorption apparatus to measure the static N2 adsorption / desorption curve of sample at liquid nitrogen temperature, and then analyzed and calculated by t-plot method.

[0020] In the present invention, the mesopore specific surface area and mesopore volume of said titanium silicon molecular sieve are measured by using Micromeritics ASAP 2460 type static nitrogen adsorption apparatus to measure the static N2 adsorption / desorption curve of sample at liquid nitrogen temperature, and then analyzed and calculated by 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 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 numerical 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 numerical 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 numerical 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 numerical 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 50%, 60%, 70%, 80%, 90%, and any value within the range of 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 is 0.13-0.37 cm 3 / g, mesopore specific surface area is 70-100m 2 / g, mesopore volume is 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 molar amounts of both are compared to obtain the surface Ti / Si (mol%) of the sample. The titanium content and silicon content of the bulk phase of the titanium silicon molecular sieve are measured by X-ray fluorescence analysis (XRF), and the molar amounts of both are compared to obtain the bulk phase Ti / Si (mol%) of the sample. The surface refers to the surface layer of the titanium silicon molecular sieve particle that can be measured by XPS, and has a theoretical depth of 8-10 nm, and the bulk phase refers to the entire particle of the titanium silicon molecular sieve.

[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 titanium silicon molecular sieve;

[0035] [ka]

[0036] where 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 the hydrothermal crystallization reaction. In addition, the titanium silicon molecular sieve has a large number of micropores, which is manifested in a high micropore specific surface area and micropore volume, and a high surface titanium content (as indicated by the surface Ti / Si being higher than the bulk phase Ti / Si). When the titanium silicon molecular sieve is used as a catalyst or catalyst support in a reaction, compared with the titanium silicon molecular sieve with mesopore channels, the confined space formed by the micropore channels can better promote the collision of reactant molecules with the framework titanium active centers on the pore walls, which can further cause adsorption and chemical reaction, and improve the conversion rate of the reactants. In addition, the increased secondary micropore structure can provide abundant mass transfer channels to shorten the diffusion path of molecules and increase the diffusion rate of reactant and product molecules, and promote the timely desorption of product molecules to avoid side reactions and improve selectivity. This feature of high titanium content on the surface can greatly shorten the diffusion paths of reactant and product molecules, improve the contact efficiency between reactants and active centers and the desorption and outward diffusion effects of product molecules, and further enhance 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 having a secondary micropore structure is formed during the hydrothermal crystallization reaction due to the weak intermolecular interaction between the alkyl chains of the silanizing reagent, and when R6 of the compound represented by formula (I) is -SH, a titanium silicon molecular sieve having a secondary micropore structure is formed during the hydrothermal crystallization reaction due to the electrostatic force between the thiols of the silanizing reagent. When R6 of the compound represented by formula (I) is -NHR7, a titanium silicon molecular sieve having a secondary micropore structure is formed during the hydrothermal crystallization reaction due to the hydrogen bonding force between the aminos of the silanizing reagent and the flexible action force of the external short-chain alkyl (R7) linked to the amino. The secondary micropore structure refers to the increased micropore structure obtained by adding a silanizing reagent in addition to the inherent micropores of the titanium silicon molecular sieve.

[0041] In the present invention, if the amount of the silanizing reagent (compound represented by formula (I)) used is too large, the crystallization property of the titanium silicon sol will be reduced, and the molecular sieve will not be obtained. If the amount of the 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, affecting its catalytic activity. Under preferred conditions, in step (1), the silicon source is calculated as SiO2, the alkaline template agent is calculated as N when it contains a nitrogen element, and OH when it does not contain a nitrogen element. ー When the titanium source is calculated as TiO2, the molar ratio of the silicon source, the alkaline template agent, the titanium source, water, the alcohol compound, and the 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 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 dropping a mixed solution of a titanium source and an alcohol compound into the mixed system and second stirring 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, preferably, step (1) further includes removing alcohol from the mixed solution, and by removing alcohol, the alcohol generated by hydrolysis of the silicon source and the titanium source can be removed, and in the present invention, it is preferable to remove the alcohol generated in the system by azeotropic distillation. In addition, when removing alcohol, water lost by azeotropic distillation is replenished so that the compounding 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, and 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 includes adding the compound represented by formula (I) to the titanium silicon sol and carrying out a 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, the nucleation and growth rate of molecular sieves at low temperatures can be controlled by rapidly increasing the temperature, and smaller molecular sieve particles can be obtained, which can be used in catalytic reactions by supporting nanogold, thereby shortening the internal diffusion path of the product, which is advantageous for improving selectivity. In addition, the rapid increase in temperature promotes the rapid hydrolysis of the silanization reagent during the molecular sieve growth process, and a secondary micropore structure is constructed. According to the present invention, in a preferred condition, in step (2), the hydrothermal crystallization is performed by heating the mixture to a crystallization temperature within 0.1 to 1 h, and then crystallizing at the crystallization temperature for 10 to 100 h, the crystallization temperature is 50 to 200 ° C., preferably, the crystallization is performed at a temperature of 100 to 200 ° C. for 20 to 80 h, more preferably, the heating time is 0.1 to 0.5 h, and more preferably, the hydrothermal crystallization conditions are a temperature of 120 to 180 ° C. and a time of 20 to 80 h. Under the above-mentioned preferable conditions, the micropore specific surface area and the micropore volume of the molecular sieve are well balanced, and a molecular sieve having a specific micropore specific surface area and micropore volume can be produced.

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

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

[0056] In a 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] The 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 micropore volume is 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 The present invention provides a nanogold-supported titanium silicon molecular sieve catalyst having a particle size of 100 to 250 nm.

[0058] In the present invention, the micropore specific surface area and micropore volume of the catalyst 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 using the t-plot method.

[0059] In the present invention, the mesopore specific surface area and mesopore volume of the catalyst 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 same 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 numerical 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 numerical 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 numerical 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 numerical 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 the 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 invention, in said 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 X-ray photoelectron spectroscopy (XPS), and the molar amounts of both are compared to obtain the surface Ti / Si (mol%) of the sample. The titanium content and silicon content of the bulk phase of the catalyst are measured by X-ray fluorescence spectroscopy (XRF), and the molar amounts of both are compared to obtain the bulk phase Ti / Si (mol%) of the sample. The surface refers to the surface layer of the titanium silicon molecular sieve particle that can be measured by XPS, and has a theoretical depth of 8-10 nm, and the bulk phase refers to the entire titanium silicon molecular sieve particle.

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

[0070] In one preferred embodiment of the invention, greater 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 0-valent, +1-valent, and +3-valent Au, and the proportion of the peak area corresponding to 0-valent Au to the total peak area is calculated to obtain the content of 0-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×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 50 nm × 50 nm region on the catalyst being 30% or less 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, the number of Au particles in each 50 nm × 50 nm region is calculated, and the region with the highest number of Au particles is region A1 and the region with the lowest number of Au particles is 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 5-40.

[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 a 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 by a high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM). The number of the Au particles within a 50 nm x 50 nm area is measured by 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 0.01wt%-1wt%, preferably 0.04wt%-0.8wt%, more preferably 0.04wt%-0.5wt%.

[0080] The third aspect of the present invention includes the steps of: treating titanium silicon molecular sieve with an aqueous aliphatic amine solution to alkali, 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 a method for preparing the nanogold-supported titanium silicon molecular sieve catalyst is provided.

[0081] In one preferred embodiment of the invention, the method comprises the steps of: (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 post-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 one preferred embodiment of the present invention, in step (1), 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, 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 performed 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, so that a large number of hydroxyl defects are generated on the titanium silicon molecular sieve, and more Au nanoparticles are easily fixed uniformly on the titanium silicon molecular sieve, which promotes the dispersion of Au on the titanium silicon molecular sieve, improves the synthesis efficiency of the oxidant in the hydro-oxidation reaction, and thus enhances the reaction effect. On the other hand, the electron induction effect of the skeleton titanium atoms on the molecular sieve is uniformly applied to the Au nanoparticles, which tend to be converted to zero-valent Au when activated. Zero-valent Au can effectively catalyze the in-situ generation of H2O2 oxidant from hydrogen gas and oxygen gas, and improve the selectivity of the product.

[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, nanogold particles will aggregate, causing side reactions during the reaction and leading to a decrease in the selectivity of the product. 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 aqueous solution used, calculated as gold, is 0.01wt%-5wt%, preferably 0.1wt%-5wt%, of the titanium silicon molecular sieve that has been post-treated with alkali.

[0089] In one preferred embodiment of the present invention, in step (2), the pH adjusting agent used to adjust the pH of the resulting mixture 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 an aqueous solution containing gold compound, add a weak alkaline pH adjuster, heat-treat the resulting mixture until the pH of the mixture is 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 weak alkaline pH adjuster is first added to slowly adjust the pH value of the chloroauric acid solution to reduce the concentration gradient, and then a strong alkaline pH adjuster is used to quickly adjust the pH of the resulting mixture to a desired range, thereby preventing Au from agglomerating into large particles, i.e., avoiding side reactions catalyzed by large Au particles, and improving the selectivity of the product.

[0092] In the present invention, in step (2), the heat treatment can increase the hydrolysis rate of the weak alkali, and avoid 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 weak 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 heat treatment temperature is 50 to 95°C.

[0096] In a 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 prepared 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 is 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 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.

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

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

[0102] In one preferred embodiment of the invention, greater 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×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 5-40.

[0105] In a 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 0.01wt%-1wt%, preferably 0.04wt%-0.8wt%, more preferably 0.04wt%-0.5wt%.

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

[0109] In one preferred embodiment of the present invention, the olefin epoxidation reaction is a propylene gas 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 includes 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, the catalyst being the nanogold-supported titanium silicon molecular sieve described in the second and fourth aspects.

[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 the inert gas is 1:1-10.

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

[0113] In the present invention, the reaction scheme of propylene gas phase epoxidation is shown in FIG. 1. As can be seen from FIG. 1, Au catalyzes the production of H2O2 from H2 and O2, 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 adopt a continuous operation mode, specifically, a catalyst is charged into a reactor, and then 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 form of the catalyst 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 realized 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 filled 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 stated, 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 the micropore volume 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 and calculating 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 the curve using the BJH method.

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

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

[0123] The pore size distribution of the micropores 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 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 by X-ray photoelectron spectroscopy (XPS). The measured XPS peak is divided by software to obtain small peaks corresponding to 0-valent, +1-valent, and +3-valent Au, and the proportion of the peak area corresponding to 0-valent Au to the total peak area is calculated to obtain the content of 0-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 shown in Table 1. Compounds 1 to 6 are all commercially available.

[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 subjected to a first stirring and mixing at room temperature to obtain a mixed system, and while stirring, a mixed solution of tetrabutyl titanate and isopropyl alcohol was dropped into the mixed system at a rate of 0.2 mL / min, and a second stirring was performed for 0.5 h 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 is 1:0.1:15, and the molar ratio of tetraethyl silicate, tetrabutyl titanate, and isopropyl alcohol is 1:0.015:3.

[0133] Next, the alcohol was removed from the mixed solution at 70°C for 8 h 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 hydrothermally crystallized at 170°C for 24 hours to obtain a crystallized product. The crystallized product was rinsed with water, filtered, and dried at 120°C for 2 hours.

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

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

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

[0139] Production Example 3 In step (2), except that compound (1) was changed to compound (3), the titanium silicon molecular sieve was prepared according to the method of Preparation Example 1. The physical property parameters of the prepared titanium silicon molecular sieve TS-1-3 are shown in Table 2.

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

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

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

[0143] Production Example 7 (1) Tetraethyl silicate, tetrapropylammonium hydroxide, and water were subjected to a first stirring and mixing at room temperature to obtain a mixed system, and while stirring, a mixed solution of tetrabutyl titanate and isopropyl alcohol was dropped into the mixed system at a rate of 0.2 mL / min, and a second stirring was performed for 0.5 h 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 is 1:0.1:15, and the molar ratio of tetraethyl silicate, tetrabutyl titanate, and isopropyl alcohol is 1:0.015:3.

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

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

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

[0147] The physical property parameters of the titanium silicon molecular sieve TS-1-7 obtained in this preparation example are shown in Table 2, and the pore size distribution diagram of the micropores 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 agent of the present invention also has a micropore channel with a pore size of about 0.55 nm, but its micropore content is much lower than that of TS-1-1 molecular sieve.

[0148] Production 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, 25 g of deionized water was added with stirring, and hydrolysis was performed at a temperature of 80°C. The alcohol was removed for 4 hours, and the evaporated water was replenished, resulting in a slightly 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] 2.0g of compound represented by formula (II) is added to the above pre-crystallization product, and stirred at room temperature for 2h to form a transparent viscous liquid. The above liquid is transferred to a stainless steel sealed reaction vessel, and kept at 90℃ for 12h, then slowly heated to 165℃ at a rate of 1℃ / min, and kept at 2d, then filtered, washed, dried at 120℃ for 12h, and roasted at 550℃ for 6h to obtain titanium silicon molecular sieve TS-1-8.

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

[0153] Production 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, 25 g of deionized water was added with stirring, and hydrolysis was performed at a temperature of 80°C. The alcohol was removed for 4 hours, and the evaporated water was replenished, resulting in a slightly 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] 2.0g compound represented by formula (III) is added to the above pre-crystallization product, and stirred at room temperature for 2 hours to form a transparent viscous liquid. The above liquid is transferred to a stainless steel sealed reaction vessel, and kept at 90℃ for 12 hours, then slowly heated to 165℃ at a rate of 1℃ / min, and kept at 2 days, and then filtered, washed, dried at 120℃ for 12 hours, and roasted at 550℃ for 6 hours to obtain titanium silicon molecular sieve TS-1-9.

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

[0158] [Table 2]

[0159] Example 1 (1) The titanium silicon molecular sieve TS-1-1 is mixed with an ethylamine aqueous solution and treated at high temperature to obtain a first suspension, which is then filtered and post-treated with alkali to obtain a titanium silicon molecular sieve. In terms of the SiO2 content of the titanium silicon molecular sieve, the molar ratio of the titanium silicon molecular sieve, the ethylamine in the ethylamine aqueous solution, and the water in the ethylamine aqueous solution is 1:0.5:10, and the high temperature treatment is 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 filter cake was activated to obtain nanogold-supported titanium silicon molecular sieve catalyst Au / TS-1-1.

[0162] Here, the activation conditions were 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 parameters of the nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-1 are shown in Table 3.

[0164] Example 2 Except for changing the titanium silicon molecular sieve TS-1-1 in step (1) to titanium silicon molecular sieve TS-1-2, the nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-2 was obtained according to the method of Example 1. The physical property parameters of the nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-2 are shown in Table 3.

[0165] Example 3 Except for changing the titanium silicon molecular sieve TS-1-1 in step (1) to titanium silicon molecular sieve TS-1-3, nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-3 was obtained according to the method of Example 1. The physical property parameters of the nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-3 are shown 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 distributed on the titanium silicon molecular sieve TS-1-3.

[0166] Example 4 Except for changing the titanium silicon molecular sieve TS-1-1 in step (1) to titanium silicon molecular sieve TS-1-4, the nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-4 was obtained according to the method of Example 1. The physical property parameters of the nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-4 are shown in Table 3.

[0167] Example 5 Except for changing the titanium silicon molecular sieve TS-1-1 in step (1) to titanium silicon molecular sieve TS-1-5, the nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-5 was obtained according to the method of Example 1. The physical property parameters of the nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-5 are shown in Table 3.

[0168] Example 6 Except for changing the titanium silicon molecular sieve TS-1-1 in step (1) to titanium silicon molecular sieve TS-1-6, the nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-6 was obtained according to the method of Example 1. The physical property parameters of the nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-6 are shown in Table 3.

[0169] Example 7 In step (2), 5g of the alkali-treated titanium silicon molecular sieve TS-1-1 is mixed with 100mL of chloroauric acid (HAuCl4) aqueous solution (0.01M), urea is added, and the mixture is heated at 70℃ until the pH of the mixture is 6, and then NaOH is added to adjust the pH to 8 to obtain a second suspension, and the nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-1-1 is obtained according to the method of Example 1. The physical property parameters 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), 5g of the alkali-treated titanium silicon molecular sieve TS-1-3 is mixed with 100mL of chloroauric acid (HAuCl4) aqueous solution (0.01M), urea is added, and the mixture is heated at 70℃ until the pH of the mixture is 6, and then NaOH is 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 is obtained according to the method of Example 3. The physical parameters 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 in step (1) is omitted, and 5 g of titanium silicon molecular sieve TS-1-1 is mixed with 100 mL of an aqueous solution of chloroauric acid (HAuCl4) (0.01 M), and NaOH is added to adjust the pH of the resulting mixture to 8 to obtain a second suspension; The nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-1-2 was obtained according to the method of Example 1, except for filtering the second suspension and activating the resulting filter cake.

[0172] The physical parameters 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 in step (1) is omitted, and 5 g of titanium silicon molecular sieve TS-1-3 is mixed with 100 mL of an aqueous solution of chloroauric acid (HAuCl4) (0.01 M), and NaOH is added to adjust the pH of the resulting mixture to 8 to obtain a second suspension; The nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-3-2 was obtained according to the method of Example 3, except for filtering the second suspension and activating the resulting filter cake.

[0174] The physical parameters of the nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-3-2 are shown in Table 3, and 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 larger in size (about 3.8 nm) and have uneven distribution in the titanium silicon molecular sieve TS-1-3-2.

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

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

[0177] Comparative Example 1 Except for changing the titanium silicon molecular sieve TS-1-1 in step (1) to titanium silicon molecular sieve TS-1-7, the nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-7 was obtained according to the method of Example 1. The physical property parameters of the nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-7 are shown in Table 3.

[0178] Comparative Example 2 Except for changing the titanium silicon molecular sieve TS-1-1 in step (1) to titanium silicon molecular sieve TS-1-8, the nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-8 was obtained according to the method of Example 1. The physical property parameters of the nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-8 are shown in Table 3.

[0179] Comparative Example 3 Except for changing the titanium silicon molecular sieve TS-1-1 in step (1) to titanium silicon molecular sieve TS-1-9, the nanogold supported titanium silicon molecular sieve catalyst Au / TS-1-9 was obtained according to the method of Example 1. The physical property parameters 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-supported titanium silicon molecular sieve prepared in Examples 1-11 and Comparative Examples 1-3 was used as a catalyst, and the catalyst was placed in a tubular reactor with an inner diameter of 8 mm, and then heated to 180°C in a N2 atmosphere, and hydrogen gas, oxygen gas, and propylene were introduced to start the reaction, and after 1 hour of reaction, the product was analyzed online. Here, the amount of catalyst used was 0.4g, and the flow rate of each gas, reaction temperature, and pressure 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, where the analysis conditions for gas chromatography were Agilent-6890 type chromatograph, molecular sieve 5A and PoraBONDU chromatography column, FID and TCD detector.

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

[0184] [Table 4]

[0185] [Table 5]

[0186] From the comparison of Measurement Examples 1 to 11 and Measurement Examples 12 to 14, it can be seen that by combining the silanization reagent of the present invention with specific crystallization conditions, a titanium silicon molecular sieve can be obtained that has a larger micropore volume, a larger micropore specific surface area, and a larger ratio of the micropore specific surface area to the total specific surface area. In addition, the obtained titanium silicon molecular sieve has a high surface titanium content, and can improve the conversion rate of propylene and the selectivity of propylene oxide.

[0187] As can be seen from the comparison of Measurement Examples 1 to 8 and Measurement Examples 9 to 11, by subjecting the titanium silicon molecular sieve to an alkali post-treatment 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 another suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed in the present invention, and all belong to the protection scope of the present invention.

Claims

1. Micropore specific surface area is 320 to 500 m ２ / g, micropore volume is 0.1-0.4 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, a particle diameter of 100 to 250 nm, and a ratio of a micropore specific surface area to a total specific surface area of ​​50% to 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 0.08-0.1 cm ３ / g, a particle size of 150 to 210 nm, and a ratio of a micropore specific surface area to a total specific surface area of ​​60% to 90%.

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

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

5. The molecular sieve according to any one of claims 1 to 4, wherein the molar ratio of titanium to silicon is 0.001-0.04:1, preferably 0.005-0.025:

1.

6. 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 0.05-0.08 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 260-410 m ２ / g, mesopore volume is 0.058-0.078 cm ３ / g, mesopore specific surface area is 45 to 80 m ２ / g and a particle size of 150 to 210 nm.

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

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

10. The catalyst according to any one of claims 6 to 9, wherein the valence of more than 90% of the gold in the nanogold is zero.

11. The catalyst according to any one of claims 6 to 10, 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 any one of claims 6 to 11, wherein the Au particles have a particle size of 0.1 to 5 nm.

13. Catalyst according to any one of claims 6 to 12, wherein the molar ratio of titanium to silicon is from 0.001 to 0.04:1, preferably from 0.005 to 0.025:

1.

14. Catalyst according to any one of claims 6 to 13, 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 preparing a nanogold supported titanium silicon molecular sieve catalyst, comprising: The method includes the steps of: treating the titanium silicon molecular sieve with an aqueous aliphatic amine solution to form an alkali; and then supporting the nanogold to obtain the catalyst; The method according to claim 1, 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 post-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 min; 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; The method according to claim 15 or 16, 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 amount 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 titanium silicon molecular sieve that has been subjected to the alkali post-treatment is mixed with an aqueous solution containing a gold compound, and a weakly alkaline pH adjuster is added. The 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 any one of claims 15 to 17, wherein the temperature of the heat treatment is preferably from 50 to 95°C.

19. A nanogold supported titanium silicon molecular sieve catalyst produced by the method according to any one of claims 15 to 18.

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

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