Titanium silicalite molecular sieve and its synthesis

Abstract

This invention relates to a titanium silicalite molecular sieve, wherein the crystal grain of the titanium silicalite molecular sieve has a ratio of (surface Si / Ti ratio):(mass Si / Ti ratio) of more than 1.1 and less than 5.

Description

TECHNICAL AREA

[0001] This invention relates to a titanium silicalite molecular sieve and its synthesis. BACKGROUND

[0002] The titanium silicalite (sometimes referred to as Ti-Si) molecular sieve is a novel heteroatom-containing molecular sieve developed in the 1980s. TS-1, with an MFI structure, TS-2, with a MEL structure, MCM-22, with an MWW structure, and TS-48, with larger pores, have been synthesized.

[0003] In the currently known direct hydrothermal synthesis of the Ti-Si molecular sieve, the organic silicon source and / or the inorganic silicon source are generally used.

[0004] Organic silicon sources, such as the organic silicate TEOS, are expensive, and the molecular sieve produced from them has a lower content of the active component. Increasing the solids content in the crystallization product during molecular sieve synthesis is difficult. Additionally, a large amount of ethanol is evaporated during sieve production. Collecting and reusing this evaporated ethanol is challenging. To reduce costs, inorganic silicon sources are used to partially or completely replace organic silicon sources. However, Ti-Si molecular sieves produced from inorganic silicon sources have lower activity. Furthermore, Ti-Si molecular sieves obtained using organic quaternary ammonium salts as template agents also exhibit lower activity.Furthermore, the Ti-Si molecular sieve, obtained by the known method, has a higher micropore volume and a lower mesopore volume. State of the art 1: US 4410501 State of the art 2: CN 1260241A SUMMARY OF THE INVENTION

[0005] To solve the problem of the titanium silicalite molecular sieve according to the prior art, this invention shall provide a new titanium silicalite molecular sieve and its synthesis method.

[0006] This invention discloses a method for synthesizing a titanium silicalite molecular sieve, comprising the following steps: (1) a titanium source, a template agent, an organic silicon source, water and an optional inorganic amine source are mixed and subjected to hydrolysis and removal of alcohols; (2) the product obtained in step (1) is aged at 15 to 50°C; (3) the aged product obtained in step (2) and a solid silicon source are homogeneously mixed, then subjected to crystallization in a closed reaction vessel, and the titanium silicalite molecular sieve is collected.

[0007] Preferably, the process of hydrolysis and removal of alcohol in step (1) is carried out by stirring the resulting mixture at 0 to 150°C or 0 to 100°C for at least 10 minutes, for example 10 minutes to 50 hours, wherein the molar ratio of the inorganic amine source to the titanium source may be (0–5):1; and / or Preferably, the aging is carried out in step (2) by leaving the product at room temperature up to 50°C for 1 to 60 hours, or 2 to 50 hours, or 3 to 30 hours, or 3 to 15 hours; and / or Preferably in step (3) the weight ratio of the aged product to the solid silicon source can be 1:0.1 to 10; the molar ratio of the titanium source to the total silicon source can be (0.005–0.05):1; the molar ratio of water to the total silicon source can be (5–100):1; the molar ratio of the template agent to the total silicon source cannot be less than 0.05:1, e.g. (0.05–0.5):1 or (0.05–0.3):1.

[0008] This invention discloses a method for synthesizing a titanium silicalite molecular sieve, comprising the following steps: (1) a titanium source, a template agent, an organic silicon source, water and an optional inorganic amine source are mixed and subjected to hydrolysis and removal of alcohols; (2) the product obtained in step (1) is aged at 15 to 50°C; (3) The aged product obtained in step (2) and a solid silicon source are homogeneously mixed, then subjected to crystallization in a closed reaction vessel, and the titanium silicalite molecular sieve is collected, wherein the template agent is an organic quaternary ammonium salt and an organic base.

[0009] Preferably, the process of hydrolysis and removal of alcohols in step (1) is carried out by stirring the resulting mixture at 0 to 150°C or 0 to 100°C for at least 10 minutes, for example 10 minutes to 50 hours, wherein the molar ratio of the inorganic amine source to the titanium source may be (0–5):1); and / or Preferably, the aging in step (2) is carried out by holding the product by leaving it at room temperature up to 50°C for 1 to 60 hours, or 2 to 50 hours, or 3 to 30 hours, or 3 to 15 hours; and / or Preferably in step (3) the weight ratio of the aged product to the solid silicon source can be 1:0.1 to 10; the molar ratio of the titanium source to the total silicon source can be (0.005–0.05):1; the molar ratio of water to the total silicon source can be (5–100):1; the molar ratio of the template agent to the total silicon source cannot be less than 0.08:1, e.g. (0.08–0.6):1 or (0.1–0.3):1.

[0010] This invention discloses a method for the synthesis of a Ti-Si micropore and mesopore molecular sieve composite, comprising the following steps: 1) A titanium source, a template agent, an organic silicon source, water and an optional inorganic amine source are mixed and subjected to hydrolysis and removal of alcohols; 2) the product obtained in step (1) is aged at 15 to 50°C; 3) The aged product obtained in step (2) and a solid silicon source are homogeneously mixed, then subjected to crystallization in a closed reaction vessel, and then the Ti-SI micropore and mesopore molecular sieve composite is collected, wherein the template agent contains an organic quaternary ammonium compound and a long-chain alkylammonium compound and optionally an organic amine.

[0011] Preferably, the process of hydrolysis and removal of alcohol in step (1) is carried out by stirring the resulting mixture at 0 to 150°C or 0 to 100°C or 50 to 95°C for at least 10 minutes, for example 10 minutes to 50 hours, wherein the molar ratio of the inorganic amine source to the titanium source may be (0–5):1; and / or Preferably, the aging in step (2) is carried out by holding the product by standing at room temperature up to 50°C for 1 to 60 hours, or 2 to 50 hours, or 3 to 30 hours, or 3 to 15 hours; and / or Preferably, in step (3), the weight ratio of the aged product to the solid silicon source may be 1:0.1–10; the molar ratio of the titanium source to the total silicon source may be (0.005–0.05):1; the molar ratio of water to the total silicon source may be (5–100):1; the molar ratio of the template agent to the total silicon source may be not less than 0.08:1, e.g., (0.08–0.6):1 or (0.1–0.3):1; and / or The template agent is an organic quaternary ammonium compound, a long-chain alkylammonium compound and optionally an organic amine, wherein the molar ratio of the organic quaternary ammonium compound to the total silicon source may be (0.04–0.45):1, the molar ratio of the long-chain alkylammonium compound to the total silicon source may be (0.04–0.45):1, the molar ratio of the organic amine to the total silicon source may be (0–0.40):1.

[0012] This invention further discloses a titanium silicalite molecular sieve characterized by: the crystal grain of the titanium silicalite molecular sieve is rich in silicon on its surface; the crystal grain has a surface Si / Ti molar ratio to mass Si / Ti molar ratio greater than 1.1, e.g., 1.1 to 5. The surface Si / Ti ratio to mass Si / Ti ratio is, for example, 1.2–4:1.

[0013] The surface Si / Ti ratio of the titanium silicalite molecular sieve crystal grain can be obtained by measuring the Si / Ti ratio of the atomic layer 5 nm or less from the crystal grain surface using XPS or TEM-EDX. The mass Si / Ti ratio of the titanium silicalite molecular sieve crystal grain can be obtained by measuring a zone 20 nm or more from the crystal grain surface using chemical analysis, XPS, XRF, or TEM-EDX. The ratio of (surface Si / Ti ratio):(mass Si / Ti ratio) is an average of measurements from at least 15 particles.

[0014] The invention further discloses a Ti-Si micropore and mesopore complex molecular sieve, wherein the Ti-Si micropore and mesopore complex molecular sieve has not only a micropore structure but also a mesopore structure. The pore diameter of the micropore is less than 1 nm, while the pore diameter of the mesopore is 2 to 8 nm. Diffraction peaks at 2θ angles of 0 to 3° and 5 to 35° are observed in the XRD spectrum for the Ti-Si micropore and mesopore complex molecular sieve. The diffraction peak at a 2θ angle of 5 to 35° in the XRD spectrum of the molecular sieve demonstrates the presence of the micropore structure within the sieve, and the diffraction peak at a 2θ angle of 0 to 3° in the XRD spectrum of the molecular sieve proves the presence of the mesopore structure within the molecular sieve. According to the Ti-Si micropore and mesopore complex molecular sieve, the micropore volume is 0.12 to 0.19 ml / g, and the mesopore volume is 0.3 to 0.8 ml / g.According to the invention, the micropore volume means the volume of pores with a pore diameter of less than 1 nm; the mesopore volume means the volume of pores with a pore diameter of 2 to 8 nm.

[0015] This invention further discloses a method for producing caprolactam by rearrangement of cyclohexanone oxime, comprising the step of contacting cyclohexanone oxime with a titanium silicalite molecular sieve, wherein the titanium silicalite molecular sieve is the titanium silicalite molecular sieve of this invention.

[0016] Specifically, this invention provides the following technical solutions: 1. Titanium silicalite molecular sieve, wherein the crystal grain of the titanium silicalite molecular sieve has a ratio of (surface Si / Ti ratio):(mass Si / Ti ratio) greater than 1.1 and less than 5. 2. Titanium silicalite molecular sieve according to any of technical solutions 1 to 7, with the exception of this technical solution, wherein the ratio of (surface Si / Ti ratio):(mass Si / Ti ratio) (1,2–4):1 is. 3. Titanium silicalite molecular sieve according to one of the technical solutions 1 to 7 with the exception of this technical solution, wherein the titanium silicalite molecular sieve has a Ti / Si molar ratio of (0.005–0.03):1, preferably (0.01–0.025):1. 4. Titanium silicalite molecular sieve according to any of technical solutions 1 to 7 with the exception of this technical solution, wherein the titanium silicalite molecular sieve is a TS-1 molecular sieve, TS-2 molecular sieve or a Ti-β molecular sieve. 5. Titanium silicalite molecular sieve according to one of technical solutions 1 to 7 with the exception of this technical solution, wherein the crystal grain of the titanium silicalite molecular sieve has a hollow structure with a radial length of 5 to 300 nm for the cavity region of the hollow grain, the adsorption capacity of benzene, measured for the molecular sieve sample under the conditions of 25°C, P / P0 = 0.10 and 1 hour adsorption time is at least 70 mg / g and there is a hysteresis loop between the adsorption isotherm and the desorption isotherm for nitrogen adsorption by the molecular sieve at a low temperature. 6. Titanium silicalite molecular sieve according to any of technical solutions 1 to 7, with the exception of this technical solution, wherein the titanium silicalite molecular sieve has a micropore structure with a pore diameter of less than 1 nm and a mesopore structure with a pore diameter of 2 to 8 nm, wherein the volume of the pores with a pore diameter of 2 to 8 nm is 0.3 to 0.8 ml / g, and the volume of the pores with a pore diameter of less than 1 nm is 0.12 to 0.19 ml / g. 7. Titanium silicalite molecular sieve according to one of the technical solutions 1 to 7 with the exception of this technical solution, wherein within a depth of 10 nm from the surface of the titanium silicalite molecular sieve to the interior of the titanium silicalite molecular sieve, in a direction from the surface to the interior, the Si / Ti ratio, based on atoms, gradually decreases “in a pattern of a quadratic function curve with a downward opening”. 8. Method for the synthesis of a titanium silicalite molecular sieve, comprising the following steps: (1) a titanium source, a template agent, an organic silicon source, water and an optional inorganic amine source are mixed and subjected to hydrolysis and removal of alcohols; (2) the product obtained in step (1) is aged at 15 to 50°C; (3) The aged product obtained in step (2) and a solid silicon source are homogeneously mixed, then subjected to crystallization in a closed reaction vessel and then the titanium silicalite molecular sieve is collected. 9. A method according to any of technical solutions 8 to 40, with the exception of this technical solution, wherein the titanium source is an organic titanium source and / or an inorganic titanium source; the template agent may be one or more compounds of an organic quaternary ammonium base, an organic amine, an organic quaternary ammonium salt, and a long-chain alkylammonium compound, wherein the molar ratio of the organic quaternary ammonium base to the total silicon source is zero or (0.05–0.36):1; the molar ratio of the organic amine to the total silicon source is (0–0.45):1; the molar ratio of the organic quaternary ammonium salt to the total silicon source is (0–0.45):1; and the molar ratio of the long-chain alkylammonium compound to the total silicon source is zero or (0.04–0.45):1;Preferably and optionally, if the content of the organic quaternary ammonium base is zero, neither the content of the organic amine nor the content of the organic quaternary ammonium salt is zero; The organic silicon source is an organic silicate with the general formula Si(OR 1 )4 exhibits, wherein R 1 a linear or branched C 1-6 -Alkyl is; The solid silicon source is a silica particle or powder of high purity, wherein, on a dry basis and based on weight, the solid silicon source has a SiO2 content of more than 99.99 wt.% and a total atomic content of Fe, Al and Na of less than 10 ppm; the inorganic amine source is an inorganic ammonium salt and / or aqueous ammonia. 10. Method according to any of the technical solutions 8 to 40 with the exception of this technical solution, wherein the molar ratio of the titanium source (as TiO2) to the total silicon source (as SiO2) is (0.005–0.05):1; the molar ratio of the template medium to the total silicon source (as SiO2) is (0.05–0.6):1; the molar ratio of water to the total silicon source (as SiO2) (5–100):1 is; the molar ratio of the inorganic amine source (as NH4) + ) to the titanium source (as TiO2) (0–5):1 is; The weight ratio of the aged product (as SiO2) to the solid silicon source (as SiO2) is 1:(0.1–10). 11. Method according to any of technical solutions 8 to 40, with the exception of this technical solution, wherein the aging in step (2) is carried out by leaving the product at 15 to 50°C for 1 to 60 hours. 12. Method according to one of the technical solutions 8 to 40 with the exception of this technical solution, wherein in step (3) the crystallization temperature is 110 to 200°C, the crystallization pressure is an autogenous pressure; and the crystallization time is 2 hours to 20 days. 13. Method according to any of technical solutions 8 to 40 with the exception of this technical solution, wherein in step (1) the template agent contains an organic quaternary ammonium base and / or an organic amine and optionally an organic quaternary ammonium salt. 14. Method according to any of the technical solutions 8 to 40, with the exception of this technical solution, wherein in step (1) the template agent contains an organic quaternary ammonium base and / or an organic amine and optionally an organic quaternary ammonium salt, wherein the molar ratio of the organic quaternary ammonium base to the organic amine is 1:(0–10) and the molar ratio of the organic quaternary ammonium base to the organic quaternary ammonium salt is 1:(0–10). 15. Method according to any of the technical solutions 8 to 40, with the exception of this technical solution, wherein in step (1) the template agent contains an organic quaternary ammonium salt and an organic base. 16. A method according to any of the technical solutions 8 to 40, with the exception of this technical solution, wherein in step (1) the template agent contains an organic quaternary ammonium salt and an organic base, wherein the molar ratio of the organic quaternary ammonium salt to the total silicon source is (0.04–0.55):1, the molar ratio of the organic quaternary ammonium base to the total aluminum salt is (0.04–0.45):1, and the molar ratio of the inorganic amine source (as NH4) is + ) to the titanium source (as TiO2) (0–0.5):1 is. 17. Method according to one of the technical solutions 8 to 40 with the exception of this technical solution, wherein in step (1) the template agent comprises an organic quaternary ammonium base and / or an organic quaternary ammonium salt, an optional organic amine and a long-chain alkylammonium compound. 18. Method according to any of the technical solutions 8 to 40, with the exception of this technical solution, wherein in step (1) the template agent comprises an organic quaternary ammonium base and / or an organic quaternary ammonium salt, an optional organic amine and a long-chain alkylammonium compound, wherein the molar ratio of the (organic quaternary ammonium base and the organic quaternary ammonium salt) to the total silicon source is (0.04–0.45):1, and the molar ratio of the long-chain alkylammonium compound to the total silicon source is (0.04–0.45):1. 19. Method according to one of the technical solutions 8 to 40, with the exception of this technical solution, wherein the template means is selected from the group consisting of: (1) an organic quaternary ammonium base and optionally a long-chain alkylammonium compound; (2) an organic quaternary ammonium salt, an organic amine and optionally a long-chain alkylammonium compound; (3) an organic quaternary ammonium salt and a long-chain alkylammonium compound. 20. A method according to any of the technical solutions 8 to 40, with the exception of this technical solution, wherein the titanium silicalite molecular sieve is a TS-1 molecular sieve, wherein the template agent is one or more of tetrapropylammonium hydroxide, tetrapropylammonium chloride and tetrapropylammonium bromide, and optionally with an organic amine and / or a long-chain alkylammonium compound; or the titanium silicalite molecular sieve is a TS-2 molecular sieve, wherein the template agent is one or more of tetrapropylammonium hydroxide, tetrapropylammonium chloride and tetrapropylammonium bromide, and optionally with an organic amine and / or a long-chain alkylammonium compound; or the titanium silicalite molecular sieve is a Ti-β molecular sieve, wherein the template agent is one or more of tetrapropylammonium hydroxide, tetrapropylammonium chloride and tetrapropylammonium bromide, and optionally with an organic amine and / or a long-chain alkylammonium compound. 21. A method according to any of technical solutions 8 to 40, with the exception of this technical solution, wherein the method further comprises a step (4): the titanium silicalite molecular sieve obtained in step (3) is subjected to crystallization in an organic base solution, and then the titanium silicalite molecular sieve is collected; the crystallization temperature may be 100 to 200°C or 100 to 150°C or 120 to 200°C or 150 to 200°C; the crystallization time may be 0.1 to 10 days or 0.5 to 10 days or 0.5 to 8 days or 0.5 to 6 days or 1 to 6 days; In step (4) the molar ratio of the titanium silicalite molecular sieve to the organic base can be 1:(0.02–0.5) or 1:(0.02–0.2); the molar ratio of the titanium silicalite molecular sieve to water can be 1:(2–50), 1:(2–30), 1:(2–20) or 1:(5–10). 22. Method according to one of the technical solutions 8 to 40, with the exception of this technical solution, wherein the titanium source is one or more of tetraalkyl titanate (Ti(Alkoxy)4), TiCl4, Ti(SO4)2 and hydrolysates thereof, wherein the alkyl group in the tetraalkyl titanate contains 1 to 6 carbon atoms. 23. Method according to one of the technical solutions 8 to 40, with the exception of this technical solution, wherein the solid silicon source is white carbon with a specific surface area of ​​50 to 400 m². 2 / g is. 24. Method according to any of the technical solutions 8 to 40, with the exception of this technical solution, wherein the molar ratio of the titanium source (as TiO2) to the total silicon source (as SiO2) is (0.005–0.040):1; (0.010–0.030):1; or (0.010–0.025):1. 25. Method according to any of the technical solutions 8 to 40, with the exception of this technical solution, wherein the molar ratio of the template medium to the total silicon source (as SiO2) is (0.05–0.30):1; (0.05–0.25):1; (0.05–0.20):1; (0.05–0.5):1; or (0.8–0.6):1. 26. Method according to any of the technical solutions 8 to 40, with the exception of this technical solution, wherein the molar ratio of water to the total silicon source (as SiO2) is (5–50):1; (6–30):1; or (6–15):1. 27. Method according to one of the technical solutions 8 to 40, with the exception of this technical solution, wherein the molar ratio of the inorganic amine source (as NH4) +) to the titanium source (as TiO2) (0.01–4):1 or (0.05–0.5):1. 28. Method according to one of the technical solutions 8 to 40, with the exception of this technical solution, wherein the molar ratio of the inorganic amine source (as NH4) + ) to the total silicon source (as SiO2) (0.01–0.07):1 or (0.01–0.05):1. 29. Method according to any of the technical solutions 8 to 40, with the exception of this technical solution, wherein the weight ratio of the aged product (as SiO2) to the total silicon source (as SiO2) is 1:(1–9) or 1:(2–8). 30. Method according to any of the technical solutions 8 to 40, with the exception of this technical solution, wherein the organic quaternary ammonium base is one or more of tetrapropylammonium hydroxide (TPAOH), tetrabutylammonium hydroxide (TBAOH) and tetraethylammonium hydroxide (TEAOH); the organic amine may be one or more of an aliphatic amine, aromatic amine and alcoholic amine; the aliphatic amine a general formula R 3 (NH2) n may have, in which R 3 C 1-4 -Alkyl or C 1-4 -Alkylene is, n 1 or 2 is; for example, one or more of ethylamine, n-butylamine, butylenediamine and hexamethylenediamine; the alcoholic amine a general formula (HOR 4 ) m NH (3-m) may have, in which R 4 C 1-4 -Alkyl is, m 1, 2 or 3 is; for example, one or more of monoethanolamine, diethanolamine and triethanolamine; the aromatic amine can be one or more of aniline, aminotoluene and p-phenylenediamine; the organic quaternary ammonium salt may be one or more of tetrapropylammonium bromide, tetrabutylammonium bromide, tetraethylammonium bromide, tetrapropylammonium chloride, tetrabutylammonium chloride and tetraethylammonium chloride; the long-chain alkylammonium compound has the formula R 5NH3X or R 5 NH3X can have, in which R 5 C 1-8 -Alkyl is, R 6 C 1-6 -Alkyl is (e.g., C 1-4 -Alkyl), wherein three R 6 in R 5 N(R 6 )3X may or may not be identical; X a monovalent anion, e.g. OH – , Cl – , Br –is; e.g., one or more of long-chain alkyltrimethylammonium chloride, long-chain alkyltrimethylammonium bromide, and long-chain alkyltrimethylammonium hydroxide; e.g., cetyltrimethylammonium bromide (CTMAB), cetyltrimethylammonium chloride, cetyltrimethylammonium hydroxide (MSDS), the long-chain alkylammonium compound being one or more of myristyltrimethylammonium bromide (TTAB), myristyltrimethylammonium chloride, myristyltrimethylammonium hydroxide, dodecyltrimethylammonium bromide (DTAB), dodecyltrimethylammonium chloride, dodecyltrimethylammonium hydroxide, octadecyltrimethylammonium bromide, octadecyltrimethylammonium chloride, octadecyltrimethylammonium hydroxide. 31. Method according to any of the technical solutions 8 to 40, with the exception of this technical solution, wherein in step (1) the time for hydrolysis and removal of alcohols is at least 10 minutes, e.g. 2 to 30 hours. 32. Method according to one of the technical solutions 8 to 40 with the exception of this technical solution, wherein in step (1) the temperature for the hydrolysis and removal of alcohols is 0 to 150°C, e.g. 50 to 95°C. 33. Method according to any of the technical solutions 8 to 40, with the exception of this technical solution, wherein in the mixture obtained in step (1) the weight content of the alcohols produced by hydrolyzing the organic silicon source and the titanium source is not higher than 10 ppm. 34. Method according to any of the technical solutions 8 to 40 with the exception of this technical solution, wherein in step (2) the aging time is 2 to 50 hours or 3 to 30 hours or 3 to 15 hours or 1 to 60 hours. 35. Method according to any of the technical solutions 8 to 40 with the exception of this technical solution, wherein in step (2) the aging temperature is room temperature up to 50°C or 15 to 30°C or 15 to 26°C or 26 to 30°C. 36. Method according to any of the technical solutions 8 to 40 with the exception of this technical solution, wherein in step (3) the crystallization temperature is 110 to 200°C, 140 to 180°C or 160 to 180°C. 37. Method according to any of the technical solutions 8 to 40 with the exception of this technical solution, wherein in step (3) the crystallization time is 2 hours to 20 days, 0.5 to 20 days, 0.5 to 10 days or 1 to 6 days or 0.5 to 6 days or 0.5 to 3 days or 1 to 3 days. 38. Method according to one of the technical solutions 8 to 40 with the exception of this technical solution, wherein in step (3) the crystallization pressure is an autogenous pressure. 39. Method according to any of the technical solutions 8 to 40 with the exception of this technical solution, wherein in step (3) the crystallization is carried out under the following conditions: the crystallization is carried out at 100 to 130°C, e.g. at 110 to 130°C for 0.5 to 1.5 days and then at 160 to 180°C for 1 to 3 days, and the crystallization pressure is an autogenous pressure. 40. Method according to any of the technical solutions 8 to 40, with the exception of this technical solution, wherein the organic silicate is one or more of tetramethyl orthosilicate, tetraethyl orthosilicate, tetrabutyl orthosilicate and dimethyl diethyl orthosilicate. EXPLANATION OF THE DRAWINGS

[0017] Fig. 1 is an XRD spectrum of the MFI-structured TS-1 molecular sieve.

[0018] Fig. Figure 2 is a TEM image of the titanium silicalite molecular sieve.

[0019] Fig. Figure 3 is an XRD spectrum of the Ti-β molecular sieve.

[0020] Fig. Figure 4 is a TEM image of the titanium silicalite molecular sieve.

[0021] Fig. Figure 5 is a SEM image of the titanium silicalite molecular sieve.

[0022] Fig. Figure 6 is an XRD spectrum of the MFI-structured Ti-Si micropore / mesopore molecular sieve.

[0023] Fig. 7 is an XRD spectrum (at a small angle) of the MFI-structured Ti-Si micropore / mesopore molecular sieve.

[0024] Fig. Figure 8 is a low-temperature nitrogen adsorption and desorption curve of the Ti-Si micropore / mesopore molecular sieve.

[0025] Fig. Figure 9 is a TEM image of the titanium silicalite molecular sieve.

[0026] Fig. Figure 10 is a SEM image of the BEA-structured titanium silicalite molecular sieve.

[0027] Fig. Figure 11 is an etching curve for the titanium silicalite molecular sieve.

[0028] Fig. Figure 12 is a time-concentration curve for H2O2 decomposition. DETAILED DESCRIPTION

[0029] If, according to the invention, a ratio contains the total silicon source, the organic silicon source, the solid silicon source (also referred to as the inorganic silicon source), and the aged product, the ratio is calculated as SiO2 unless otherwise specified; if a ratio includes the inorganic amine source, the inorganic ammonium salt, and aqueous ammonia, the ratio is calculated as NH4 + Calculated unless otherwise specified; if a ratio includes water, the ratio is calculated as H2O unless otherwise specified; if a ratio includes a titanium source, the ratio is calculated as TiO2 unless otherwise specified.

[0030] The titanium silicalite molecular sieve has a higher surface Si / Ti ratio (mass Si / Ti ratio) and higher oxidation activity. When used in an oxidation reaction involving H₂O₂, the decomposition effect of Ti in the surface layer on H₂O₂ can be reduced. This is advantageous for reducing the activity of the side reaction, in which H₂O₂ is ineffectively decomposed, and is useful for increasing the range of applications of the starting material.

[0031] In the process for synthesizing the titanium silicalite molecular sieve of this invention, the inexpensive and readily available solid silicon source, such as high-purity silica gel and / or carbon white, can be used to partially or completely substitute the expensive organic silicon source, and / or the organic quaternary ammonium salt is used to substitute the organic quaternary ammonium base. This reduces waste emissions during the production of the molecular sieve and lowers the cost of the starting materials.

[0032] In the process for synthesizing the titanium silicalite molecular sieve of this invention, the organic quaternary ammonium salt can be used as a template agent instead of the organic quaternary ammonium base to produce the titanium silicalite molecular sieve. The resulting molecular sieve has a smaller crystal grain size and higher activity than those produced according to the prior art using the organic quaternary ammonium salt.

[0033] In the process for synthesizing the titanium silicalite molecular sieve of this invention, the titanium silicalite molecular sieve can be produced with a lower amount of template agent and a lower ratio of water to total silicon source. The costs of synthesizing the titanium silicalite molecular sieve can be significantly reduced, and the solids content in the crystallization product during the synthesis of the molecular sieve and the single-tank molecular sieve output can be increased.

[0034] This invention further discloses a method for producing caprolactam by converting cyclohexanone oxime, comprising the step of contacting cyclohexanone oxime with a titanium silicalite molecular sieve, wherein the titanium silicalite molecular sieve is the titanium silicalite molecular sieve of this invention.

[0035] In a process for synthesizing the titanium silicalite molecular sieve of this invention, the titanium silicalite molecular sieve can be synthesized using a lower amount of template agent. For example, the molar ratio of the template agent to the total silicon source can be (0.05–0.3):1, e.g., (0.05–0.25):1, (0.1–0.3):1, (0.1–0.25):1, or (0.05–0.2):1.

[0036] In the process for synthesizing the titanium silicalite molecular sieve of this invention, the titanium silicalite molecular sieve can be synthesized at a higher solids content, thus reducing the amount of water used and increasing the single-boiler output (i.e., the molecular sieve can be produced in a single synthesis using the same reactor volume). Therefore, the molar ratio of water to the total silicon source can be lower, e.g., (6–80):1, (5–50):1, (6–30):1, (6–20):1, (5–30):1, or (6–15):1. MATERIAL

[0037] In a process for synthesizing the titanium silicalite molecular sieve, the material used contains a titanium source, a template agent, a total silicon source, an inorganic amine source, and water. The total silicon source comprises a combination of an organic silicon source and an inorganic silicon source; the inorganic silicon source is also referred to as the solid silicon source.

[0038] In one embodiment, the molar ratio of the titanium source to the total silicon source can be (0.01–0.05):1. In another embodiment, the molar ratio of the titanium source to the total silicon source can be (0.005–0.05):1. In another embodiment, the molar ratio of the titanium source to the total silicon source can be (0.01–0.03):1. In another embodiment, the molar ratio of the titanium source to the total silicon source can be (0.01–0.025):1. In another embodiment, the molar ratio of the template agent to the total silicon source cannot be less than 0.05:1. In another embodiment, the molar ratio of the template agent to the total silicon source cannot be less than 0.08:1. In another embodiment, the molar ratio of the template agent to the total silicon source can be (0.05–0.30):1.In one embodiment, the molar ratio of the template agent to the total silicon source can be (0.05–0.20):1. In another embodiment, the molar ratio of the template agent to the total silicon source can be (0.08–0.60):1. In another embodiment, the molar ratio of the template agent to the total silicon source can be (0.05–0.20):1. In another embodiment, the molar ratio of the template agent to the total silicon source can be (0.10–0.25):1. In another embodiment, the molar ratio of the template agent to the total silicon source can be (0.10–0.20):1. In another embodiment, the molar ratio of the template agent to the total silicon source can be (0.10–0.30):1. In one embodiment, the molar ratio of the inorganic amine source to the total silicon source can be (0.01–0.07):1.In one embodiment, the molar ratio of the inorganic amine source to the total silicon source can be (0.01–0.05):1. In another embodiment, the molar ratio of water to the total silicon source can be (6–20):1. In another embodiment, the molar ratio of the inorganic amine source to the titanium source can be (0–5):1. In another embodiment, the molar ratio of the inorganic amine source to the titanium source can be (0.01–4):1. In another embodiment, the molar ratio of the inorganic amine source to the titanium source can be (0.01–0.5):1. In another embodiment, the molar ratio of the inorganic amine source to the titanium source can be (0.05–0.5):1.

[0039] The introduction of the inorganic amine source can increase the oxidation activity of the synthesized molecular sieve, increase the utilization rate of the titanium source (a higher frame Ti / Si ratio can be obtained with the same amount of titanium source used), and reduce the amount of titanium source used. TITANIUM SOURCE

[0040] The titanium source is an organic or inorganic titanium compound, for example, one or more tetraalkyl titanates (Ti(alkoxy)4), TiCl4, Ti(SO4)2, and their hydrolysates. The alkyl group in the tetraalkyl titanate contains 1 to 6 carbon atoms, e.g., 1, 2, 3, 4, 5, or 6 carbon atoms.

[0041] In one embodiment, the molar ratio of the titanium source to the total silicon source can be (0.005–0.050):1. In another embodiment, the molar ratio of the titanium source to the total silicon source can be (0.008–0.035):1. In another embodiment, the molar ratio of the titanium source to the total silicon source can be (0.010–0.030):1. In another embodiment, the molar ratio of the titanium source to the total silicon source can be (0.010–0.025):1. In another embodiment, the molar ratio of the titanium source to the total silicon source can be (0.015–0.025):1. TEMPLATE MEDIUM

[0042] The template agent can be an organic base or an organic base and an organic quaternary ammonium salt. For example, the template agent can be an organic quaternary ammonium base, a mixture of an organic quaternary ammonium base and an organic amine, a mixture of an organic quaternary ammonium base and an organic quaternary ammonium salt, a mixture of an organic amine or an organic quaternary ammonium salt, or a mixture of an organic quaternary ammonium base, an organic quaternary ammonium salt, and an organic amine.

[0043] The template agent may also contain a long-chain alkylammonium compound. For example, the template agent may contain an organic quaternary ammonium compound, a long-chain alkylammonium compound, and optionally an organic amine.

[0044] The organic base can be one or more of an organic quaternary ammonium base and an organic amine.

[0045] The organic amine can be one or more of an aliphatic amine, aromatic amine, and alcoholic amine.

[0046] The aliphatic amine can have the general formula R 3 (NH2) n have, in which R 3 C 1-4 -Alkyl or C 1-4 -Alkylene is and n is 1 or 2. The aliphatic amine can be one or more of ethylamine, n-butylamine, butylenediamine, and hexamethylenediamine.

[0047] The alcoholic amine can be the general formula (HOR 4 ) m NH (3-m) have, in which R 4 C 1-4 -Alkyl, m 1, 2 or 3. The alcoholic amine can be one or more of monoethanolamine, diethanolamine and triethanolamine.

[0048] The aromatic amine refers to an amine with an aromatic substituent and can be one or more of aniline, aminotoluene, and p-phenylenediamine.

[0049] The organic quaternary ammonium compound can have the general formula R 7 4NX 7 have, in which R 7 is C1, C2, C3, C4, C5 or C4 alkyl, X 7 a monovalent anion, e.g. OH – , Cl – or Br – The organic quaternary ammonium compound is an organic quaternary ammonium base and / or an organic quaternary ammonium salt.

[0050] According to the invention, the organic quaternary ammonium base can be one or more of tetrapropylammonium hydroxide (TPAOH), tetrabutylammonium hydroxide (TBAOH) and tetraethylammonium hydroxide (TEAOH).

[0051] According to the invention, the organic quaternary ammonium salt can be one or more of tetrapropylammonium bromide, tetrabutylammonium bromide, tetraethylammonium bromide, tetrapropylammonium chloride, tetrabutylammonium chloride and tetraethylammonium chloride.

[0052] The long-chain alkylammonium compound can have the formula R 5 NH3X or R 5 N(R 6 )3X have, in which R 5 C 12-18 -Alkyl is, R 6 C 1-6 -Alkyl is (e.g., C 1-4 -alkyl), e.g. B. methyl, ethyl, propyl, butyl, pentyl or hexyl, in which three R 6 in R 5 N(R 6 )3X may or may not be identical; S is a monovalent anion, e.g. OH – , Cl – , Br – ; if X OH – The compound is referred to as an alkaline long-chain alkylammonium compound according to the invention.

[0053] According to this invention, the long-chain alkyl C relates to 12-18 -Alkyl.

[0054] The long-chain alkylammonium compound is, for example, one or more of a long-chain alkyltrimethylammonium chloride, a long-chain alkyltrimethylammonium bromide, or a long-chain alkyltrimethylammonium hydroxide. The long-chain alkylammonium compound is, for example, one or more of cetyltrimethylammonium bromide (CTMAB), cetyltrimethylammonium chloride, cetyltrimethylammonium hydroxide (MSDS), myristyltrimethylammonium bromide (TTAB), myristyltrimethylammonium chloride, myristyltrimethylammonium hydroxide, dodecyltrimethylammonium bromide (DTAB), dodecyltrimethylammonium chloride, dodecyltrimethylammonium hydroxide, octadecyltrimethylammonium bromide, octadecyltrimethylammonium chloride, and octadecyltrimethylammonium hydroxide.

[0055] In one embodiment, the template agent can contain an organic quaternary ammonium base. For example, the template agent can be an organic quaternary ammonium base or a mixture comprising an organic quaternary ammonium base. For example, the template agent can be a mixture of an organic quaternary ammonium base and an organic amine, or a mixture of an organic quaternary ammonium base and an organic quaternary ammonium salt, or a mixture of an organic quaternary ammonium base, an organic quaternary ammonium salt, and an organic amine.

[0056] In one embodiment, the molar ratio of the organic quaternary ammonium base to the total silicon source can be (0.05–0.36):1.

[0057] In one embodiment, the molar ratio of the organic quaternary ammonium base to the total silicon source can be (0.05–0.3):1.

[0058] In one embodiment, the molar ratio of the organic quaternary ammonium base to the total silicon source can be (0.05–0.2):1.

[0059] In one embodiment, the molar ratio of the organic amine to the total silicon source can be (0–0.45):1.

[0060] In one embodiment, the molar ratio of the organic amine to the total silicon source can be (0–0.35):1.

[0061] In one embodiment, the molar ratio of the organic amine to the total silicon source can be (0.05–0.25):1.

[0062] In one embodiment, the molar ratio of the organic quaternary ammonium salt to the total silicon source can be (0–0.45):1.

[0063] In one embodiment, the molar ratio of the organic quaternary ammonium salt to the total silicon source can be (0.05–0.3):1.

[0064] In one embodiment, the molar ratio of the organic quaternary ammonium base to the organic amine can be 1:(0–10).

[0065] In one embodiment, the molar ratio of the organic quaternary ammonium base to the organic amine can be 1:(0–8).

[0066] In one embodiment, the molar ratio of the organic quaternary ammonium base to the organic quaternary ammonium salt can be 1:(0–10).

[0067] In one embodiment, the molar ratio of the organic quaternary ammonium base to the organic quaternary ammonium salt can be 1:(0–8).

[0068] In one embodiment, the molar ratio of the organic quaternary ammonium base to the total silicon source can be (0.05–0.45):1.

[0069] In one embodiment, the template agent may contain an organic base, wherein the organic base is an organic quaternary ammonium base and / or an organic amine.

[0070] In one embodiment, the molar ratio of the organic base to the total silicon source cannot be less than 0.04:1.

[0071] In one embodiment, the molar ratio of the organic base to the total silicon source cannot be less than 0.05:1.

[0072] In one embodiment, the molar ratio of the organic base to the total silicon source can be (0.05–0.45):1.

[0073] In one embodiment, the template agent may contain an organic base, wherein the organic base is one or more of an organic quaternary ammonium base, a long-chain alkylammonium hydroxide, and an organic amine.

[0074] In one embodiment, the molar ratio of the organic base to the total silicon source cannot be less than 0.04:1.

[0075] In one embodiment, the molar ratio of the organic base to the total silicon source cannot be less than 0.05:1.

[0076] In one embodiment, the molar ratio of the organic base to the total silicon source can be (0.05–0.45):1.

[0077] In one embodiment, the template agent may contain an organic quaternary ammonium compound, wherein the organic quaternary ammonium compound is an organic quaternary ammonium base and / or an organic quaternary ammonium salt.

[0078] In one embodiment, the molar ratio of the organic quaternary ammonium compound to the total silicon source cannot be less than 0.05:1.

[0079] In one embodiment, the molar ratio of the organic quaternary ammonium compound to the total silicon source can be (0.05–0.45):1.

[0080] In one embodiment, the molar ratio of the organic quaternary ammonium compound to the total silicon source can be (0.05–0.30):1.

[0081] In one embodiment, the molar ratio of the organic quaternary ammonium compound to the total silicon source can be (0.05–0.25):1.

[0082] In one embodiment, the molar ratio of the organic quaternary ammonium compound to the total silicon source can be (0.05–0.20):1.

[0083] In one embodiment, the template agent is an organic quaternary ammonium salt and an organic amine.

[0084] In one embodiment, the molar ratio of the organic quaternary ammonium salt to the total silicon source can be (0.05–0.3):1.

[0085] In one embodiment, the molar ratio of the organic quaternary ammonium salt to the total silicon source can be (0.05–0.2):1.

[0086] In one embodiment, the molar ratio of the organic amine to the total silicon source can be (0.05–0.45):1.

[0087] In one embodiment, the molar ratio of the organic amine to the total silicon source can be (0.05–0.40):1.

[0088] In one embodiment, the molar ratio of the organic amine to the total silicon source can be (0.05–0.35):1.

[0089] In one embodiment, the molar ratio of the organic amine to the total silicon source can be (0.05–0.30):1.

[0090] In one embodiment, the molar ratio of the organic amine to the total silicon source can be (0.10–0.25):1.

[0091] In one embodiment, the molar ratio of the organic amine to the total silicon source can be (0–0.40):1.

[0092] In one embodiment, the template agent can contain an organic quaternary ammonium salt and an organic amine.

[0093] In one embodiment, the molar ratio of the organic quaternary ammonium salt to the total silicon source can be (0.05–0.3):1.

[0094] In one embodiment, the molar ratio of the organic quaternary ammonium salt to the total silicon source can be (0.05–0.2):1.

[0095] In one embodiment, the molar ratio of the organic amine to the total silicon source can be (0.05–0.45):1.

[0096] In one embodiment, the molar ratio of the organic amine to the total silicon source can be (0.05–0.40):1.

[0097] In one embodiment, the molar ratio of the organic amine to the total silicon source can be (0.05–0.35):1.

[0098] In one embodiment, the molar ratio of the organic amine to the total silicon source can be (0.05–0.30):1.

[0099] In one embodiment, the molar ratio of the organic amine to the total silicon source can be (0.05–0.25):1.

[0100] In one embodiment, the molar ratio of the organic amine to the total silicon source can be (0–0.40):1.

[0101] In one embodiment, the template agent can contain a long-chain alkylammonium compound.

[0102] In one embodiment, the molar ratio of the long-chain alkylammonium compound to the total silicon source can be (0.05–0.40):1.

[0103] In one embodiment, the molar ratio of the long-chain alkylammonium compound to the total silicon source can be (0.05–0.35):1.

[0104] In one embodiment, the molar ratio of the long-chain alkylammonium compound to the total silicon source can be (0.05–0.25):1.

[0105] In one embodiment, the template agent can contain an organic quaternary ammonium compound and a long-chain alkylammonium compound and optionally an organic amine compound, wherein the molar ratio of the organic quaternary ammonium compound to the total silicon source can be (0.04–0.45):1, the molar ratio of the long-chain alkylammonium compound to the total silicon source can be (0.04–0.45):1, and the molar ratio of the organic amine to the total silicon source can be (0–0.4):1.

[0106] In one embodiment of the process for the synthesis of the titanium silicalite molecular sieve of this invention, the template agent comprises an organic quaternary ammonium compound and a long-chain alkylammonium compound, wherein the molar ratio of the organic quaternary ammonium compound to the total silicon source may be (0.05–0.45):1, and the molar ratio of the long-chain alkylammonium compound to the total silicon source may be (0.05–0.45):1.

[0107] In one embodiment of the process for synthesizing the titanium silicalite molecular sieve of this invention, the template composition contains at least one organic quaternary base. The organic base is one or more of the organic quaternary ammonium base, the organic amine, and the alkaline long-chain alkylammonium compound. The molar ratio of the organic base in the template composition to the total silicon source can be (0.04–0.5):1, e.g., (0.05–0.45):1. ENTIRE SILICON SOURCE

[0108] According to the invention, the entire silicon source is a combination of the organic silicon source and the inorganic silicon source (also referred to as the solid silicon source).

[0109] According to the invention, the organic silicon source can be an organic silicate.

[0110] The organic silicate can be given the general formula Si(OR 1 )4 have, wherein R 1 C 1-6 -alkyl may be, for example, wherein R 1 C 1-4 -alkyl can be linear or branched.

[0111] The organic silica can be one or more of tetramethyl orthosilicate, tetraethyl orthosilicate, tetrabutyl orthosilicate and dimethyl diethyl orthosilicate.

[0112] Among others, the preferred compound is one or more of tetramethyl orthosilicate, tetraethyl orthosilicate, dimethyl diethyl orthosilicate.

[0113] According to the invention, the solid silicon source can be a high-purity silica solid or powder.

[0114] In one embodiment, on a dry basis and based on weight, the solid silicon source has a SiO2 content of not less than 99.99 wt.% and a total weight content of Fe, Al and Na, based on the atom, of less than 10 ppm.

[0115] In one embodiment, on a dry basis and based on weight, the solid silicon source has a SiO2 content of 99.99 wt.% to 100 wt.%, generally more than 99.99 wt.% and less than 100 wt.%.

[0116] In one embodiment, the solid silicon source can be white carbon and / or high-purity silica gel.

[0117] In one embodiment, on a dry basis and based on weight, the high-purity silica gel can have a SiO2 content of not less than 99.99 wt.%, for example more than 99.99 wt.% and less than 100 wt.%, and a total weight content of Fe, Al and Na, based on atoms, of less than 10 ppm.

[0118] In one embodiment, on a dry basis and based on weight, the white carbon can have a SiO2 content of not less than 99.99 wt.%, for example 99.99 wt.% to 100 wt.% or more than 99.99 wt.% and less than 100 wt.%, and a total weight content of Fe, Al and Na, based on atoms, of less than 10 ppm.

[0119] In one embodiment, white carbon can have a specific surface area of ​​(50 to 400) m² 2 / g have.

[0120] White carbon is commercially available or can be produced according to existing methods. For example, the method for producing white carbon is disclosed in CN101798088B. For instance, white carbon can be obtained by the combustion reaction of SiCl4, H2, and O2. INORGANIC AMEMIN SOURCE

[0121] According to this invention, the inorganic amine source can be an inorganic ammonium salt and / or aqueous ammonia. The inorganic ammonium salt can be one or more of ammonium chloride, ammonium nitrate, and ammonium sulfate. The inorganic amine source is preferably aqueous ammonia.

[0122] The introduction of the inorganic amine source (e.g., inorganic ammonium salt) can increase the frame Ti content of the synthesized molecular sieve and the activity of the molecular sieve. TITAN SILICALITE MOLECULAR SIEVE

[0123] This invention further discloses a titanium silicalite molecular sieve characterized as follows: the crystal grain of the titanium silicalite molecular sieve is rich in silicon on the surface, the crystal grain has a ratio of (surface Si / Ti molar ratio):(mass Si / Ti molar ratio) of more than 1.1, for example 1.1 to 5. The ratio of (surface Si / Ti ratio):(mass Si / Ti ratio) is, for example, 1.2–4:1.

[0124] The surface Si / Ti ratio of the crystal grain of the titanium silicalite molecular sieve can be obtained by measuring the Si / Ti ratio of the atomic layer that is 5 nm or less away from the surface of the crystal grain using XPS or TEM-EDX.

[0125] The mass-Si / Ti ratio of the crystal grain of the titanium silicalite molecular sieve can be obtained by measuring a zone that is 20 nm or more away from the surface of the crystal grain, using chemical analysis, XPS, XRF or TEM-EDX.

[0126] The ratio of (surface area Si / Ti ratio):(mass Si / Ti ratio) is an average of measurements from at least 15 particles.

[0127] The titanium silicalite molecular sieve can have a crystal grain size (in the short axis direction) of 140 nm to 2 μm, e.g. 200 nm to 2 μm or 200 nm to 700 nm.

[0128] The titanium silicalite molecular sieve particle is a single crystal grain or an aggregate formed from many crystal grains.

[0129] The titanium silicalite molecular sieve can be a TS-1 molecular sieve, a TS-2 molecular sieve, or a Ti-beta molecular sieve.

[0130] The titanium silicalite molecular sieve can be an MFI-structured Ti-Si micropore and mesopore complex molecular sieve, a MEL-structured Ti-Si micropore and mesopore complex molecular sieve, or a BEA-structured Ti-Si micropore and mesopore complex molecular sieve.

[0131] In one embodiment, the titanium silicalite molecular sieve is a TS-1 molecular sieve; the template agent used can be tetrapropylammonium hydroxide or a mixture of tetrapropylammonium hydroxide or one or more of the organic amine, tetrapropylammonium chloride, and tetrapropylammonium bromide.

[0132] In one embodiment, the titanium silicalite molecular sieve is a TS-2 molecular sieve; the template agent used can be tetrabutylammonium hydroxide or a mixture of tetrabutylammonium hydroxide or one or more of the organic amine, tetrabutylammonium chloride and tetrabutylammonium bromide.

[0133] In one embodiment, the titanium silicalite molecular sieve is a Ti-beta molecular sieve; the template agent used can be tetraethylammonium hydroxide or a mixture of tetraethylammonium hydroxide or one or more of the organic amines, tetraethylammonium chloride and tetraethylammonium bromide.

[0134] In one embodiment, the titanium silicalite molecular sieve is a TS-1 molecular sieve, and the template agent used can be a mixture of tetrapropylammonium chloride and / or tetrapropylammonium bromide and the organic amine.

[0135] In one embodiment, the titanium silicalite molecular sieve is a TS-2 molecular sieve, and the template agent used can be a mixture of tetrabutylammonium chloride and / or tetrabutylammonium bromide and the organic amine.

[0136] In one embodiment, the titanium silicalite molecular sieve is a Ti-beta molecular sieve, and the template agent used can be a mixture of tetraethylammonium chloride and / or tetraethylammonium bromide and the organic amine.

[0137] In one embodiment, the titanium silicalite molecular sieve is an MFI-structured Ti-Si micropore and mesopore complex molecular sieve, and the organic quaternary ammonium compound used can be tetrapropylammonium hydroxide, tetrapropylammonium chloride, and tetrapropylammonium bromide. In one embodiment, the molar ratio of one or more of the tetrapropylammonium hydroxide, tetrapropylammonium chloride, and tetrapropylammonium bromide to the total silicon source can be not less than 0.01:1, for example, (0.02–0.2):1 or (0.04–0.15):1.

[0138] In one embodiment, the titanium silicalite molecular sieve is a MEL-structured Ti-Si micropore and mesopore complex molecular sieve. The organic quaternary ammonium compound used may contain tetrabutylammonium hydroxide, tetrabutylammonium bromide, and tetrabutylammonium chloride, or be one or more of these. In another embodiment, the molar ratio of one or more of the tetrabutylammonium hydroxide, tetrabutylammonium bromide, and tetrabutylammonium chloride to the total silicon source may be not less than 0.01:1, for example, (0.02–0.2):1 or (0.04–0.15):1.

[0139] In one embodiment, the titanium silicalite molecular sieve is a BEA-structured Ti-Si micropore and mesopore complex molecular sieve. The organic quaternary ammonium compound used may contain tetraethylammonium hydroxide, tetraethylammonium bromide, and tetraethylammonium chloride, or be one or more of these. In another embodiment, the molar ratio of one or more of the tetraethylammonium hydroxide, tetraethylammonium bromide, and tetraethylammonium chloride to the total silicon source may be not less than 0.01:1, for example, (0.02–0.2):1 or (0.04–0.15):1. Synthesis process

[0140] In one embodiment, the method for synthesizing the Ti-Si micropore and mesopore complex molecular sieve of this invention comprises the following steps: (1) a titanium source, a template agent, an organic silicon source, an inorganic amine source and water are mixed and stirred; (2) the product obtained in step (1) is aged; (3) The aged product obtained in step (2) and a solid silicon source are homogeneously mixed, then subjected to crystallization in a closed reaction vessel, and the titanium silicalite molecular sieve is collected; and (4) Alternatively, the molecular sieve is recrystallized.

[0141] In step (1) the inorganic amine source is preferably aqueous ammonia.

[0142] In one embodiment, the molar ratio of aqueous ammonia to the total silicon source can be (0.01–0.1):1.

[0143] In one embodiment, the molar ratio of aqueous ammonia to the total silicon source can be (0.01–0.07):1.

[0144] In one embodiment, the molar ratio of aqueous ammonia to the total silicon source can be (0.01–0.05):1.

[0145] In one embodiment, the molar ratio of aqueous ammonia to the total silicon source can be (0–5):1.

[0146] In one embodiment, the molar ratio of aqueous ammonia to the total silicon source can be (0.01–4):1.

[0147] In one embodiment, the molar ratio of aqueous ammonia to the total silicon source can be (0.01–0.5):1.

[0148] In step (1), a titanium source, a template agent, an organic silicon source, an inorganic amine source, and water are mixed. The resulting mixture is stirred at 0 to 150°C, e.g., 0 to 100°C, e.g., 10 to 100°C, e.g., 20 to 100°C, e.g., 50 to 95°C, e.g., 50 to 90°C, for at least 10 minutes, so that the organic silicon source and the titanium source are hydrolyzed, and the content of the monohydric alcohol in the resulting mixture is reduced, i.e., it undergoes hydrolysis and removal of the alcohols. Generally, the stirring time is 10 to 3,000 minutes, e.g., 2 to 30 hours.

[0149] A clear hydrolysis solution is obtained from the organic silicon and titanium sources by hydrolysis and removal of alcohols. Generally, the weight content of alcohols generated by hydrolysis of the organic silicon and titanium sources in the mixture obtained in step (1) is not higher than 10 ppm. Preferably, the weight content of the monohydric alcohol in the mixture obtained in step (1) is not higher than 10 ppm.

[0150] In step (2), the product obtained in step (1) is aged. During aging, the product obtained in step (1) is left to stand at room temperature (15 to 40°C) for 1 to 60 hours. The room temperature is 15 to 40°C; the aging time is 1 to 60 hours, e.g., 2 to 50 hours, e.g., 3 to 50 hours, e.g., 3 to 30 hours, e.g., 3 to 15 hours. No stirring is performed during aging, and the product obtained in step (1) is preserved by standing.

[0151] In step (3), the aged product obtained in step (2) and the solid silicon source are mixed. The molar ratio of the product obtained in step (2) and the solid silicon source, as SiO2, is 1:(0.10–10) (i.e., the molar ratio of the organic silicon source to the solid silicon source is equal to the weight ratio), e.g., 1:(0.2–9), 1:(1–9), 1:(2–8), 1:(1–7), 1:(3–7), or 1:(3–6). The aged product obtained in step (2) and the solid silicon source are mixed homogeneously and stirred. Generally, the stirring time is at least 15 minutes, e.g., 0.5 to 5 hours.

[0152] In the process for synthesizing the titanium silicalite molecular sieve of this invention, a higher proportion of the solid silicon source can be used, the solids content of the crystallization product can be increased, and therefore the performance for a single synthesis can be increased without changing the synthesis reactor.

[0153] In step (3) the crystallization temperature is 110 to 200°C, for example 140 to 180°C or 160 to 180°C.

[0154] In step (3), the crystallization pressure is an autogenous pressure.

[0155] In step (3) the crystallization time is 2 hours to 20 days, 0.5 to 20 days, 0.5 to 10 days or 1 to 6 days or 0.5 to 6 days or 0.5 to 3 days or 1 to 3 days.

[0156] Crystallization can be carried out in a stainless steel mixing container.

[0157] The temperature increase during crystallization can be a single-stage or multi-stage process. It can be carried out using conventional methods. The rate of temperature increase can be (0.5 to 1)°C per minute.

[0158] In one embodiment, the crystallization is carried out under the following conditions: the crystallization temperature is 160 to 180°C, the crystallization time is 0.5 to 6 days or 0.5 to 3 days or 1 to 3 days, and the crystallization pressure is an autogenous pressure.

[0159] In one embodiment, crystallization is carried out under the following conditions: crystallization is performed at 100 to 130°C, e.g. 110 to 130°C for 0.5 to 1.5 days and then at 160 to 180°C for 1 to 3 days; the crystallization pressure is an autogenous pressure.

[0160] In step (3) the process for collecting the titanium silicalite molecular sieve is a conventional procedure and may include filtering the crystallization product and washing and calcining or filtering the crystallization product and washing, drying and calcining.

[0161] The aim of the filtration is to separate the titanium silicalite molecular sieve, obtained by crystallization, from the crystallization mother solution.

[0162] The aim of washing is to remove the silicon-containing template agent solution (e.g., TPAOH solution) that is adsorbed on the surface of the molecular sieve particles.

[0163] The aim of drying is to remove most of the water from the molecular sieve in order to reduce the amount of water evaporation during calcination.

[0164] The goal of calcination is to remove the template agent from the molecular sieve.

[0165] In step (3), washing can be carried out with water, in which the weight ratio of the molecular sieve to water can be 1:(1–20) or 1:(1–15). The washing temperature can be room temperature up to 50°C.

[0166] The drying temperature can be between 100 and 200°C.

[0167] The calcination temperature can range from 350 to 650°C. The calcination time can range from 2 to 10 hours.

[0168] The product of the titanium silicalite molecular sieve of this invention is obtained by collection.

[0169] According to the process for synthesizing the titanium silicalite molecular sieve of this invention, the titanium silicalite molecular sieve obtained by collection in step (3) can also be subjected to a molecular sieve rearrangement, i.e., the titanium silicalite molecular sieve obtained in step (3) is subjected to crystallization in a solution of an organic base, and then the titanium silicalite molecular sieve is collected. This process enables the titanium silicalite molecular sieve to have a hollow structure.

[0170] Specifically, the titanium silicalite molecular sieve obtained in step (3) is mixed with an organic base and water. The resulting mixture is subjected to crystallization in a closed reaction vessel, and then the product is collected. The crystallization pressure can be autogenous. The crystallization temperature can be 100 to 200°C, 100 to 150°C, 120 to 200°C, or 150 to 200°C. The crystallization time can be 0.1 to 10 days, 0.5 to 10 days, 0.5 to 8 days, 0.5 to 6 days, or 1 to 6 days.

[0171] In one embodiment, in step (4) the molar ratio of the titanium silicalite molecular sieve: the organic base: water can be 1:(0.02–0.5):(2–50), for example 1:(0.05–0.2):(2–20).

[0172] In one embodiment, in step (4) the molar ratio of the titanium silicalite molecular sieve to the organic base can be 1:(0.02–0.5) or 1:(0.02–0.2), and the molar ratio of titanium silicalite molecular sieve to water can be 1:(2–50), 1:(2–30), 1:(2–20) or 1:(5–10).

[0173] In step (4), the organic base is an organic quaternary ammonium base and / or an organic amine; the organic quaternary ammonium base is, for example, one or more of tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, and tetraethylammonium hydroxide; the organic amine is one or more of aliphatic amines, aromatic amines, and alcoholic amines; the aliphatic amine may have the general formula R 3 (NH2) n have, in which R 3 C 1-4 -Alkyl or C 1-4 -Alkylene is, n 1 or 2 is; the alcoholic amine can have the general formula (HOR 4 ) m NH (3-m) have, in which R 4 C1-4 -Alkyl or m 1, 2, or 3. An aliphatic amine is, for example, one or more of ethylamine, β-butylamine, butylenediamine, and hexamethylenediamine. An aromatic amine is an amine with an aromatic substituent, such as one or more of aniline, aminotoluene, or p-phenylenediamine. An alcoholic amine is, for example, one or more of monoethanolamine, diethanolamine, and triethanolamine.

[0174] In step (4), the organic base is preferably an organic quaternary ammonium base, wherein the molar ratio of the molecular sieve (as SiO2) to the organic quaternary ammonium base is 1:(0.02–0.5), for example 1:(0.05–0.2); the molar ratio of the molecular sieve (as SiO2) to water is (1:82–50), for example 1:(2–20) or 1:(5–10); the crystallization temperature is 120 to 200°C; the crystallization time is 0.5 to 8 days; and the crystallization pressure is an autogenous pressure. Preferably, in step (4), the crystallization temperature is 150 to 200°C and the crystallization time is 0.5 to 6 days.

[0175] In step (4) the collection process is conventional, and reference can be made to a collection process in step (3). In general, this includes filtering the crystallization product, washing, drying (optionally) and calcining.

[0176] In one embodiment, the titanium silicalite molecular sieve is a TS-1 molecular sieve, and the organic quaternary ammonium base used in step (4) is tetrapropylammonium hydroxide.

[0177] In one embodiment, the titanium silicalite molecular sieve is a TS-2 molecular sieve, and the organic quaternary ammonium base used in step (4) is tetrabutylammonium hydroxide.

[0178] In one embodiment, the titanium silicalite molecular sieve is a Ti-beta molecular sieve, and the organic quaternary ammonium base used in step (4) is tetraethylammonium hydroxide.

[0179] In one embodiment, the titanium silicalite molecular sieve is an MFI-structured Ti-Si micropore and mesopore molecular sieve, and the organic quaternary ammonium base used in step (4) is tetrapropylammonium hydroxide.

[0180] In one embodiment, the titanium silicalite molecular sieve is a MEL-structured Ti-Si micropore and mesopore molecular sieve, and the organic quaternary ammonium base used in step (4) is tetrabutylammonium hydroxide.

[0181] In one embodiment, the titanium silicalite molecular sieve is a BEA-structured Ti-Si micropore and mesopore molecular sieve, and the organic quaternary ammonium base used in step (4) is tetraethylammonium hydroxide.

[0182] The rearrangement of the molecular sieve in step (4) can be repeated once or more than once. This repetition serves to carry out the treatment of step (4), but replaces the titanium silicalite molecular sieve obtained in step (3) with the molecular sieve that was treated in step (4).

[0183] Through rearrangement treatment, a titanium silicalite molecular sieve with a secondary pore structure can be obtained. The crystal grain of the resulting titanium silicalite molecular sieve has a hollow structure with a radial length of 5 to 300 nm for the hollow grain area. The adsorption capacity of benzene, measured for the molecular sieve sample at 25°C, P / P0 = 0.10, and after 1 hour of adsorption time, is at least 70 mg / g. A hysteresis loop exists between the adsorption and desorption isotherms for nitrogen adsorption by the molecular sieve at low temperatures. The molecular sieve has a higher pore volume and a higher specific surface area. MEASUREMENT

[0184] The surface Si / Ti ratio of the titanium silicalite molecular sieve crystal grain can be obtained by measuring the Si / Ti ratio of the atomic layer 5 nm or less from the crystal grain surface using XPS or TEM-EDX. The mass Si / Ti ratio of the titanium silicalite molecular sieve crystal grain can be obtained by measuring a zone 20 nm or more from the crystal grain surface using chemical analysis, XPS, XRF, or TEM-EDX. The ratio of (surface Si / Ti ratio):(mass Si / Ti ratio) is an average of measurements from at least 15 particles.

[0185] According to this invention, the crystal grain size is determined using SEM.

[0186] The change in the Si / Ti atom ratio within the 10 nm depth from the surface of the crystal grain of the titanium silicalite molecular sieve to the interior of the crystal grain of the titanium silicalite molecular sieve is obtained by XPS etching. INSTRUMENTS

[0187] The XRD result is obtained using a Siemens D5005-type X-ray diffraction diffractometer. Radiation source: CuKα (λ = 1.5418 Å), tube voltage: 40 kV, tube current: 40 mA, sampling rate: 0.5° / minute, sampling range 2θ = 4°–40°.

[0188] Specific BET surface area and pore volume are determined by nitrogen adsorption capacity measurement in combination with the BJH calculation method, according to the standard procedure RIPP151-90. Reference can be made to Analytical Methods in Petrochemical Industry (RIPP Experiment Techniques), Yang Cuiding et al., Science Press, 1990.

[0189] The SEM result is obtained using a Quanta 200E-type scanning electron microscope (manufactured by FEI). The sample is dried and coated with gold by vacuum evaporation to increase electrical conductivity and contrast. The analysis electron microscope acceleration voltage is 20.0 kV and the magnification is 1 to 30 k.

[0190] The XPS result is obtained using an ESCALAB 250-type X-ray diffraction photoelectron spectrometer (manufactured by Thermo Fischer-VG), Al Kα monochromator, Mg / Al binode, Mg Kα X-rays, power: 200 W, the binding energy is corrected with alkyl carbon or the contaminated C1s peak (284.8 eV).

[0191] The etching analysis is performed with Ar + -Sputtering used, excitation source: Mg Kα X binode, the basic vacuum level is approximately 6.5 × 10 –7 Pa (in the analysis process).

[0192] The TEM or TEM-EDX result is obtained using a Tecnai F20 G2S-TWIN type transmission electron microscope (manufactured by FEI) equipped with a GIF2001 energy filter system (Gatan). Additional information is provided by an X-ray diffraction energy spectrometer. The electron microscope sample is dispersed by suspension on a 3 mm diameter microgrid.

[0193] The XRF result is obtained using a 3271E-type X-ray diffraction fluorescence spectrometer (Rigaku Industrial Corporation). The sample is obtained by powder tableting. Target: Rhodium, excitation voltage: 50 kV, excitation current: 50 mA. The spectral line intensity of each element is determined by a scintillation counter and a proportional counter. MATERIAL Tetrapropylammonium bromide: Guang Dong Dayou Chemical Plant with a concentration of 20.05 wt.%. Tetrapropylammonium chloride: Guang Dong Dayou Chemical Plant with a concentration of 20.05 wt.%. Tetrapropylammonium hydroxide (TPAOH): Guang Dong Dayou Chemical Plant with a concentration of 25.05 wt.%. Tetraethyl orthosilicate, analytically pure: Sinopharm Chemical Reagent Limited Corporation. Tetrapropylammonium bromide solid, analytically pure: Sinopharm Chemical Reagent Limited Corporation. Long-chain alkyltriammonium bromide, analytically pure: Sinopharm Chemical Reagent Limited Corporation. Aqueous ammonia, analytically pure, 20 wt.% carbon white, available from JuHua (ZheJiang), model AS-150; solids content > 95 wt.%, SiO2 content (dry base) > 99.99 wt.%, total content of Fe, Na and Al > 10 ppm, specific surface area 195 m² 2 / G. Tetrabutyl titanate, analytically pure: Sinopharm Chemical Reagent Limited Corporation. Titanyl sulfate, analytically pure: Sinopharm Chemical Reagent Limited Corporation.

[0194] Other agents are commercially available and analytically pure. Triethylamine, analytically pure: Sinopharm Chemical Reagent Limited Corporation. Ethylenediamine, analytically pure: Sinopharm Chemical Reagent Limited Corporation.

[0195] In the examples, the surface area-to-silicon (Si / Ti) ratio and the mass-to-silicon (Mass-Si / Ti) ratio were measured using TEM-EDX. For each sample, 20 particles were randomly selected and measured with respect to their surface area-to-silicon (Si / Ti) ratio and mass-to-silicon (Mass-Si / Ti) ratio. The ratio of (surface area-to-Si / Ti ratio):(mass-to-Si / Ti ratio) was then calculated. The average of 20 calculated values ​​was recorded as the (surface area-to-Si / Ti ratio):(mass-to-Si / Ti ratio) of the sample. EXAMPLE 1 (1) To a 500 ml beaker, 15 g of aqueous tetrapropylammonium hydroxide (TPAOH) solution (at a concentration of 25.05 wt%), 2.04 g of tetrabutyl titanate, 8.5 g of tetraethyl orthosilicate, 2 g of aqueous ammonia (at a concentration of 20 wt%), and 38 g of water were successively added. A magnetic stir bar with heating and stirring functions was placed in the beaker. The mixture was stirred for 4 hours at 80°C. Water was added to the mixture as needed. A colorless and clear hydrolysis solution was obtained. (2) The resulting hydrolysis solution was left to stand at 26°C for 12 hours to form an aged product. (3) 9.6 g of white carbon powder were added to the aged product while stirring. The resulting mixture was stirred for 1 hour to form a viscous substance, which was transferred to a closed stainless steel reactor vessel and crystallized at a constant temperature of 165°C for 2 days. After filtering the resulting mixture, the filter cake was washed, dried at 120°C for 24 hours, and calcined at 550°C for 6 hours to produce a TS-1 molecular sieve product, TS-1 F1, which has a specific BET surface area of ​​425 m². 2 / g, an outer surface area of ​​60 m² 2 / g, had a micropore volume of 0.166 ml / g and a mesopore volume of 0.086 ml / g.

[0196] XRD analysis showed that the molecular sieve had an MFI structure.

[0197] The XRD spectrum is in Fig. 1 shown. (4) 6 g of the TS-1 molecular sieve product TS-1 F1 and an aqueous TPAOH solution (with a concentration of 22.05 wt%) were homogeneously mixed, the weight ratio of the TS-1 molecular sieve product TS-1 F1 to the aqueous TPAOH solution being 1:5. The resulting mixture was crystallized at 150°C in a closed reaction vessel for 3 days. After filtering the resulting mixture, the filter cake was washed, dried at 120°C for 24 hours, and calcined at 550°C for 6 hours to produce the recrystallized TS-1 molecular sieve product TS-1 P1, which has a specific BET surface area of ​​457 m². 2 / g, an outer surface area of ​​68 m² 2 / g, had a micropore volume of 0.152 ml / g and a mesopore volume of 0.168 ml / g.

[0198] XRD confirmed that the molecular sieve exhibited similar characteristic peaks as in Fig. 1, which proved that the molecular sieve had an MFI structure.

[0199] The transmission electron microscope (TEM) image showed that the molecular sieve had a hollow structure, as in Fig. 2 is shown. EXAMPLE 2 (1) To a 500 ml beaker, 7.4 g of aqueous tetrapropylammonium hydroxide (TPAOH) solution (at a concentration of 25.05 wt%), 1.23 g of tetrabutyl titanate, 4.16 g of tetraethyl orthosilicate, 0.67 g of aqueous ammonia (at a concentration of 20 wt%), and 14 g of water were successively added. A magnetic stir bar with heating and stirring functions was placed in the beaker. The mixture was stirred for 1 hour at 90°C. Water was added to the mixture as needed. A colorless and clear alkaline hydrolysis solution was obtained. (2) The resulting hydrolysis solution was left to stand at 26°C for 3 hours to form an aged product. (3) 9.6 g of white carbon powder were added to the aged product with stirring. The resulting mixture was stirred for 1.5 hours to form a viscous substance, which was transferred to a closed stainless steel reactor vessel and crystallized at a constant temperature of 145°C for 6 days. After filtering the resulting mixture, the filter cake was washed, dried at 120°C for 24 hours, and calcined at 550°C for 6 hours to produce a TS-1 molecular sieve product, TS-1 F2, which has a specific BET surface area of ​​435 m². 2 / g, an outer surface area of ​​61 m² 2 / g, had a micropore volume of 0.159 ml / g and a mesopore volume of 0.083 ml / g.

[0200] XRD confirmed that the molecular sieve exhibited similar characteristic peaks as in Fig. 1, which proved that the molecular sieve had an MFI structure. (4) 6 g of the TS-1 molecular sieve product TS-1 F2 and 36 g of aqueous TPAOH solution (with a concentration of 22.05 wt%) were homogeneously mixed. The resulting mixture was crystallized at 150°C in a closed reaction vessel for 3 days. After filtering the resulting mixture, the filter cake was washed, dried at 120°C for 24 hours, and calcined at 550°C for 6 hours to produce the recrystallized TS-1 molecular sieve product TS-1 P2, which has a specific BET surface area of ​​429 m². 2 / g, an outer surface area of ​​60 m² 2 / g, had a micropore volume of 0.150 ml / g and a mesopore volume of 0.177 ml / g. The transmission electron microscope (TEM) image showed that the molecular sieve had a hollow structure.

[0201] XRD confirmed that the molecular sieve exhibited similar characteristic peaks as in Fig. 1, which proved that the molecular sieve had an MFI structure. EXAMPLE 3 (1) To a 500 ml beaker, 43 g of aqueous tetrapropylammonium bromide (TPABr) solution (at a concentration of 25.05 wt%), 1.68 g of titanyl sulfate, 2.4 g of triethylamine, 33.3 g of tetraethyl orthosilicate, 0.05 g of aqueous ammonia (at a concentration of 20 wt%), and 26 g of water were successively added. A magnetic stir bar with heating and stirring functions was placed in the beaker. The mixture was stirred for 3 hours at 65°C. Water was added to the mixture as needed. A hydrolysis solution was obtained. (2) The resulting hydrolysis solution was left to stand for 9 hours at 26°C to form an aged product. (3) 9.6 g of white carbon powder were added to the aged product while stirring. The resulting mixture was stirred for 1 hour to form a viscous substance, which was transferred to a closed stainless steel reactor vessel and crystallized at a constant temperature of 165°C for 2 days. After filtering the resulting mixture, the filter cake was washed, dried at 120°C for 24 hours, and calcined at 550°C for 6 hours to produce a TS-1 molecular sieve product, TS-1 F3, which has a specific BET surface area of ​​427 m². 2 / g, an outer surface area of ​​60 m² 2 / g, had a micropore volume of 0.173 ml / g and a mesopore volume of 0.079 ml / g. (4) 6 g of the TS-1 molecular sieve product TS-1 F3 and 40 g of aqueous TPAOH solution (with a concentration of 22.05 wt%) were homogeneously mixed. The resulting mixture was crystallized at 150°C in a closed reaction vessel for 3 days. After filtering the resulting mixture, the filter cake was washed, dried at 120°C for 24 hours, and calcined at 550°C for 6 hours to produce the recrystallized TS-1 molecular sieve product TS-1 P3, which has a specific BET surface area of ​​438 m². 2 / g, an outer surface area of ​​59 m² 2 / g, had a micropore volume of 0.162 ml / g and a mesopore volume of 0.183 ml / g.

[0202] The transmission electron microscope (TEM) image showed that the molecular sieve had a hollow structure. EXAMPLES 4 to 7

[0203] Titanium silicalite molecular sieves were prepared according to Example 1. The material, working conditions, and analytical results for these examples are shown in Tables 1 to 3. See Example 1 for the other conditions. EXAMPLE 8

[0204] Titanium silicalite molecular sieve was prepared according to Example 1, except that no inorganic amine source was added. The material, working conditions, and analytical results for this example are shown in Tables 1 to 3. See Example 1 for the other conditions. EXAMPLE 9

[0205] Titanium silicalite molecular sieve was prepared according to Example 1, except that in step (3) crystallization was carried out at 120°C for 1 day and then at 170°C for 2 days. The material, working conditions, and analytical result for this example are shown in Tables 1 to 3. See Example 1 for the other conditions. EXAMPLE 10

[0206] Titanium silicalite molecular sieve was prepared according to Example 1 (TS-2 molecular sieve), with the exception of the material fraction and the template agent. The template agent used was tetrabutylammonium hydroxide (TBAOH). The material and working conditions for this example are shown in Tables 1 and 2. EXAMPLE 11

[0207] Titanium silicalite molecular sieve was prepared according to Example 1 (Ti-β molecular sieve), with the exception of the material fraction and the template agent. The template agent used was tetraethylammonium hydroxide (TEAOH). The material and working conditions for this example are shown in Tables 1 and 2. The XRD spectrum is shown in Fig. 3 shown. COMPARISON EXAMPLE 1

[0208] Titanium silicalite molecular sieve was prepared according to Example 1, except that aging was omitted. The material, working conditions, and analytical results for this example are shown in Tables 1 to 3. See Example 1 for further conditions. COMPARISON EXAMPLE 2

[0209] Titanium silicalite molecular sieve was prepared according to Example 1, except that the aging temperature was 75°C. The material, working conditions, and analytical results for this example are shown in Tables 1 to 3. See Example 1 for further conditions. COMPARISON EXAMPLE 3

[0210] Titanium silicalite molecular sieves were prepared according to Example 1, except that the solid silicon source was added in step (1). The material, working conditions, and analytical result for this example are shown in Tables 1 to 3. See Example 1 for further conditions. EXAMPLE 12 (1) To a 500 ml beaker, 19.65 g of aqueous tetrapropylammonium bromide (TPABr) solution (at a concentration of 25.05 wt%), 2.04 g of tetrabutyl titanate, 8.5 g of tetraethyl orthosilicate, 2.42 g of ethylenediamine, 2 g of aqueous ammonia (at a concentration of 20 wt%), and 35 g of water were successively added. A magnetic stir bar with heating and stirring functions was placed in the beaker. The mixture was stirred for 4 hours at 80°C. Water was added to the mixture as needed. A colorless and clear hydrolysis solution was obtained. (2) The resulting hydrolysis solution was left to stand at 26°C for 12 hours to form an aged product. (3) 9.6 g of white carbon powder were added to the aged product while stirring. The resulting mixture was stirred for 1 hour to form a viscous substance, which was transferred to a closed stainless steel reactor vessel and crystallized at a constant temperature of 165°C for 2 days. After filtering the resulting mixture, the filter cake was washed, dried at 120°C for 24 hours, and calcined at 550°C for 6 hours to produce a TS-1 molecular sieve product, TS-1 F4, which has a specific BET surface area of ​​420 m². 2 / g, an outer surface area of ​​58 m² 2 / g, had a micropore volume of 0.165 ml / g and a mesopore volume of 0.077 ml / g.

[0211] XRD confirmed that the molecular sieve exhibited similar characteristic peaks as in Fig. 1, which proved that the molecular sieve had an MFI structure. (4) 6 g of the TS-1 molecular sieve product TS-1 F4 and an aqueous TPAOH solution (with a concentration of 22.05 wt%) were homogeneously mixed. The weight ratio of the TS-1 molecular sieve product TS-1 F4 to the aqueous TPAOH solution was 1:5. The resulting mixture was crystallized at 150°C in a closed reaction vessel for 3 days. After filtering the resulting mixture, the filter cake was washed, dried at 120°C for 24 hours, and calcined at 550°C for 6 hours to produce the recrystallized TS-1 molecular sieve product TS-1 P4, which has a specific BET surface area of ​​460 m². 2 / g, an outer surface area of ​​65 m² 2 / g, had a micropore volume of 0.153 ml / g and a mesopore volume of 0.173 ml / g.

[0212] XRD confirmed that the molecular sieve exhibited similar characteristic peaks as in Fig. 1, which proved that the molecular sieve had an MFI structure.

[0213] The transmission electron microscope (TEM) image showed that the molecular sieve had a hollow structure, as in Fig. 4 is shown. EXAMPLE 13 (1) To a 500 ml beaker, 15 g of aqueous tetrapropylammonium bromide (at a concentration of 25.5 wt%), 2.04 g of tetrabutyl titanate, 8.5 g of tetraethyl orthosilicate, 0.55 g of ethylenediamine, 2 g of aqueous ammonia (at a concentration of 20 wt%), and 120 g of water were successively added. A magnetic stir bar with heating and stirring functions was placed in the beaker. The mixture was stirred for 1 hour at 90°C. Water was added to the mixture as needed. A colorless and clear hydrolysis solution was obtained. (2) The resulting hydrolysis solution was left to stand at 26°C for 3 hours to form an aged product. (3) 9.6 g of white carbon powder were added to the aged product while stirring. The resulting mixture was stirred for 1.5 hours to form a viscous substance, which was transferred to a closed stainless steel reactor vessel and crystallized at a constant temperature of 145°C for 6 days. After filtering the resulting mixture, the filter cake was washed, dried at 120°C for 24 hours, and calcined at 550°C for 6 hours to produce a TS-1 molecular sieve product, TS-1 F5, which has a specific BET surface area of ​​428 m². 2 / g, an outer surface area of ​​59 m² 2 / g, had a micropore volume of 0.173 ml / g and a mesopore volume of 0.078 ml / g.

[0214] XRD confirmed that the molecular sieve exhibited similar characteristic peaks as in Fig. 1, which proved that the molecular sieve had an MFI structure. (4) 6 g of the TS-1 molecular sieve product TS-1 F5 and 36 g of aqueous TPAOH solution (with a concentration of 22.5 wt%) were mixed and stirred homogeneously. The resulting mixture was crystallized at 150°C in a closed reaction vessel for 3 days. After filtering the resulting mixture, the filter cake was washed, dried at 120°C for 24 hours, and calcined at 550°C for 6 hours to produce the recrystallized TS-1 molecular sieve product TS-1 P5, which has a specific BET surface area of ​​442 m². 2 / g, an outer surface area of ​​60 m² 2 / g, had a micropore volume of 0.167 ml / g and a mesopore volume of 0.163 ml / g.

[0215] The transmission electron microscope (TEM) image showed that the molecular sieve had a hollow structure.

[0216] XRD confirmed that the molecular sieve exhibited similar characteristic peaks as in Fig. 1, which proved that the molecular sieve had an MFI structure. EXAMPLE 14 (1) To a 500 ml beaker, 43 g of aqueous tetrapropylammonium bromide solution (at a concentration of 25.05 wt%), 1.68 g of titanyl sulfate, 2.4 g of triethylamine, 33.3 g of tetraethyl orthosilicate, 0.05 g of aqueous ammonia (at a concentration of 20 wt%), and 26 g of water were successively added. A magnetic stir bar with heating and stirring functions was placed in the beaker. The mixture was stirred for 3 hours at 65°C. Water was added to the mixture as needed. An alkaline hydrolysis solution was obtained. (2) The resulting hydrolysis solution was left to stand for 9 hours at 26°C to form an aged product. (3) 9.6 g of white carbon powder were slowly added to the aged product while stirring. The resulting mixture was stirred for 1 hour to form a viscous substance, which was transferred to a closed stainless steel reactor vessel and crystallized at a constant temperature of 165°C for 2 days. After filtering the resulting mixture, the filter cake was washed, dried at 120°C for 24 hours, and calcined at 550°C for 6 hours to produce a TS-1 molecular sieve product, TS-1 F6, which has a specific BET surface area of ​​432 m². 2 / g, an outer surface area of ​​58 m² 2 / g, had a micropore volume of 0.159 ml / g and a mesopore volume of 0.076 ml / g.

[0217] XRD confirmed that the molecular sieve exhibited similar characteristic peaks as in Fig. 1, which proved that the molecular sieve had an MFI structure. (4) 6 g of the TS-1 molecular sieve product TS-1 F6 and 40 g of aqueous TPAOH solution (with a concentration of 22.05 wt%) were homogeneously mixed. The resulting mixture was crystallized at 150°C in a closed reaction vessel for 3 days. After filtering the resulting mixture, the filter cake was washed, dried at 120°C for 24 hours, and calcined at 550°C for 6 hours to produce the recrystallized TS-1 molecular sieve product TS-1 P6, which has a specific BET surface area of ​​438 m². 2 / g, an outer surface area of ​​59 m² 2 / g, had a micropore volume of 0.143 ml / g and a mesopore volume of 0.185 ml / g.

[0218] The transmission electron microscope (TEM) image showed that the molecular sieve had a hollow structure.

[0219] XRD confirmed that the molecular sieve exhibited similar characteristic peaks as in Fig. 1, which proved that the molecular sieve had an MFI structure. EXAMPLE 15 to 19

[0220] Titanium silicalite molecular sieves were prepared according to Example 12. The material, working conditions, and analytical results for the examples are shown in Tables 1 to 3. See Example 12 for the other conditions. EXAMPLE 20

[0221] A titanium silicalite molecular sieve was prepared according to Example 12, except that in step (3) crystallization was carried out at 120°C for 1 day and then at 170°C for 2 days. The material, working conditions, and analytical result for this example are shown in Tables 1 to 3. See Example 1 for the other conditions. EXAMPLE 21

[0222] Titanium silicalite molecular sieve was prepared according to Example 12 (TS-2 molecular sieve), with the exception of the material fraction and the template agent. The template agent used was tetrabutylammonium hydroxide (TBAOH). The material and working conditions for this example are shown in Tables 1 and 2. EXAMPLE 22

[0223] Titanium silicalite molecular sieve was prepared according to Example 12 (Ti-β molecular sieve), with the exception of the material fraction and the template agent. The template agent used was tetraethylammonium hydroxide (TEAOH). The material and working conditions for this example are shown in Tables 1 and 2.

[0224] XRD confirmed that the molecular sieve exhibited similar characteristic peaks as in Fig. 3 had, which proved that the molecular sieve had a BEA structure.

[0225] The SEM photo is in Fig. 5 shown. COMPARISON EXAMPLE 4

[0226] Titanium silicalite molecular sieve was prepared according to Example 12, except that aging was omitted. The material, working conditions, and analytical results for this example are shown in Tables 1 to 3. See Example 1 for further conditions. COMPARISON EXAMPLE 5

[0227] Titanium silicalite molecular sieve was prepared according to Example 12, except that the aging temperature was 75°C. The material, working conditions, and analytical results for this example are shown in Tables 1 to 3. See Example 1 for further conditions. COMPARISON EXAMPLE 6

[0228] Titanium silicalite molecular sieves were prepared according to Example 12, except that the solid silicon source was added in step (1). The material, working conditions, and analytical result for this example are shown in Tables 1 to 3. See Example 1 for further conditions. EXAMPLE 23 (1) To a 500 ml beaker, 15 g of aqueous tetrapropylammonium hydroxide (TPAOH) solution (at a concentration of 25.05 wt%), 2.04 g of tetrabutyl titanate, 5.62 g of cetyltrimethylammonium hydroxide (MSDS), 8.5 g of tetraethyl orthosilicate, 2 g of aqueous ammonia (at a concentration of 20 wt%), and 38 g of water were successively added. A magnetic stir bar with heating and stirring functions was placed in the beaker. The mixture was stirred for 4 hours at 80°C. Water was added to the mixture as needed. A colorless and clear hydrolysis solution was obtained. (2) The resulting hydrolysis solution was left to stand at 26°C for 12 hours to form an aged product. (3) 9.6 g of white carbon powder were added to the aged product while stirring. The resulting mixture was stirred for 1 hour to form a viscous substance, which was transferred to a closed stainless steel reactor vessel and crystallized at a constant temperature of 165°C for 2 days. After filtering the resulting mixture, the filter cake was washed, dried at 120°C for 24 hours, and calcined at 550°C for 6 hours to produce a TS-1 molecular sieve product, TS-1 F7, which has a specific BET surface area of ​​449 m². 2 / g, an outer surface area of ​​58 m² 2 / g, had a micropore volume of 0.152 ml / g and a mesopore volume of 0.385 ml / g.

[0229] XRD analysis showed that the molecular sieve has an MFI structure.

[0230] The XRD spectra are in Fig. 6 and Fig. 7 shown.

[0231] The low-temperature nitrogen adsorption and desorption curve is shown in Fig. 8 shown.

[0232] (4) 6 g of the TS-1 molecular sieve product TS-1 F7 and an aqueous TPAOH solution (with a concentration of 22.05 wt%) were mixed and stirred homogeneously. The weight ratio of TS-1 F7 to the aqueous TPAOH solution was 1:5. The resulting mixture was crystallized at 150°C in a closed reaction vessel for 3 days. After filtering the resulting mixture, the filter cake was washed, dried at 120°C for 24 hours, and calcined at 550°C for 6 hours to produce the recrystallized TS-1 molecular sieve product TS-1 P7, which has a specific BET surface area of ​​477 m². 2 / g, an outer surface area of ​​62 m² 2 / g, had a micropore volume of 0.153 ml / g and a mesopore volume of 0.388 ml / g.

[0233] XRD confirmed that the molecular sieve exhibited similar characteristic peaks as in Fig. 6 and Fig. 7, which proved that the molecular sieve had an MFI structure.

[0234] The transmission electron microscope (TEM) image showed that the molecular sieve had a hollow structure, as in Fig. 9 is shown. EXAMPLE 24 (1) To a 500 ml beaker, 7.4 g of aqueous tetrapropylammonium hydroxide (at a concentration of 25.05 wt%), 1.23 g of tetrabutyl titanate, 3.29 g of cetyltrimethylammonium bromide (CTMAB), 4.16 g of tetraethyl orthosilicate, 0.67 g of aqueous ammonia (concentration of 20 wt%), and 14 g of water were successively added. A magnetic stir bar with heating and stirring functions was placed in the beaker. The mixture was stirred for 1 hour at 90°C. Water was added to the mixture as needed. A colorless and clear alkaline hydrolysis solution was obtained. (2) The resulting hydrolysis solution was left to stand at 26°C for 3 hours to form an aged product. (3) 9.6 g of white carbon powder were slowly added to the aged product while stirring. The resulting mixture was stirred for 1.5 hours. The resulting mixture was transferred to a closed stainless steel reactor vessel and crystallized at a constant temperature of 165°C for 2 days. After filtering the resulting mixture, the filter cake was washed, dried at 120°C for 24 hours, and calcined at 550°C for 6 hours to produce a TS-1 molecular sieve product, TS-1 F8, which had a micropore volume of 0.157 ml / g and a mesopore volume of 0.365 ml / g.

[0235] XRD confirmed that the molecular sieve exhibited similar characteristic peaks as in Fig. 6 and Fig. 7, which proved that the molecular sieve had an MFI structure. (4) 6 g of the TS-1 molecular sieve product TS-1 F8 and 36 g of aqueous TPAOH solution (with a concentration of 22.05 wt%) were mixed and stirred homogeneously. The resulting mixture was crystallized at 150°C in a closed reaction vessel for 3 days. After filtering the resulting mixture, the filter cake was washed, dried at 120°C for 24 hours, and calcined at 550°C for 6 hours to produce the recrystallized TS-1 molecular sieve product TS-1 P8, which had a micropore volume of 0.154 ml / g and a mesopore volume of 0.372 ml / g.

[0236] XRD confirmed that the molecular sieve exhibited similar characteristic peaks as in Fig. 6 and Fig. 7, which proved that the molecular sieve had an MFI structure.

[0237] The transmission electron microscope (TEM) image showed that the molecular sieve had a hollow structure. EXAMPLE 25 (1) To a 500 ml beaker, 43 g of aqueous tetrapropylammonium bromide solution (at a concentration of 25.05 wt%), 1.68 g of titanium sulfate, 5.62 g of cetyltrimethylammonium hydroxide, 2.4 g of triethylamine, 33.3 g of tetraethyl orthosilicate, 0.05 g of aqueous ammonia (at a concentration of 20 wt%), and 26 g of water were successively added. A magnetic stir bar with heating and stirring functions was placed in the beaker. The mixture was stirred for 3 hours at 65°C. Water was added to the mixture as needed. An alkaline hydrolysis solution was obtained. (2) The resulting hydrolysis solution was left to stand for 9 hours at 26°C to form an aged product. (3) 9.6 g of white carbon powder were added to the aged product with stirring. The resulting mixture was stirred for 1 hour to form a viscous substance, which was transferred to a closed stainless steel reactor vessel and crystallized at a constant temperature of 165°C for 2 days. After filtering the resulting mixture, the filter cake was washed, dried at 120°C for 24 hours, and calcined at 550°C for 6 hours to produce a TS-1 molecular sieve product, TS-1 F9, which had a micropore volume of 0.146 ml / g and a mesopore volume of 0.374 ml / g.

[0238] XRD confirmed that the molecular sieve exhibited similar characteristic peaks as in Fig. 6 and Fig. 7, which proved that the molecular sieve had an MFI structure. (4) 6 g of the TS-1 molecular sieve product TS-1 F9 and 40 g of aqueous TPAOH solution (with a concentration of 22.05 wt%) were mixed and stirred homogeneously. The resulting mixture was crystallized at 150°C in a closed reaction vessel for 3 days. After filtering the resulting mixture, the filter cake was washed, dried at 120°C for 24 hours, and calcined at 550°C for 6 hours to produce the recrystallized TS-1 molecular sieve product TS-1 P9, which had a micropore volume of 0.149 ml / g and a mesopore volume of 0.380 ml / g.

[0239] XRD confirmed that the molecular sieve exhibited similar characteristic peaks as in Fig. 6 and Fig. 7, which proved that the molecular sieve had an MFI structure.

[0240] The transmission electron microscope (TEM) image showed that the molecular sieve had a hollow structure. EXAMPLE 26 to 29

[0241] Titanium silicalite molecular sieves were prepared according to Example 23. The material, working conditions, and analytical results for the examples are shown in Tables 1 to 3. See Example 23 for the other conditions. EXAMPLE 30

[0242] Titanium silicalite molecular sieve was prepared according to Example 23. The material, working conditions, and analytical results for this example are shown in Tables 1 to 3. See Example 23 for the other conditions. EXAMPLE 31

[0243] A titanium silicalite molecular sieve was prepared according to Example 23, except that in step (3) crystallization was carried out at 120°C for 1 day and then at 170°C for 2 days. The material, working conditions, and analytical result for this example are shown in Tables 1 to 3. See Example 23 for the other conditions. EXAMPLE 32

[0244] Titanium silicalite molecular sieve was prepared according to Example 23 (MEL molecular sieve), with the exception of the material fraction and the template agent. The template agent used was tetrabutylammonium hydroxide (TBAOH). The material and working conditions for this example are shown in Tables 1 and 2. EXAMPLE 33

[0245] Titanium silicalite molecular sieve was prepared according to Example 1 (BEA molecular sieve), with the exception of the material fraction and the template agent. The template agent used was tetraethylammonium hydroxide (TEAOH). The material and working conditions for this example are shown in Tables 1 and 2.

[0246] The SEM photo is in Fig. 10 shown. Comparative example 7

[0247] Titanium silicalite molecular sieve was prepared according to Example 23, except that aging was omitted. The material, working conditions, and analytical results for this example are shown in Tables 1 to 3. See Example 23 for further conditions. COMPARISON EXAMPLE 8

[0248] Titanium silicalite molecular sieve was prepared according to Example 23, except that the aging temperature was 75°C. The material, working conditions, and analytical results for this example are shown in Tables 1 to 3. See Example 23 for further conditions. COMPARISON EXAMPLE 9

[0249] Titanium silicalite molecular sieve was prepared according to Example 23, except that the solid silicon source was added in step (1). The material, working conditions, and analytical result for this example are shown in Tables 1 to 3. See Example 23 for further conditions. COMPARISON EXAMPLE 10

[0250] Production of the conventional titanium silicalite molecular sieve (Zeolites, 1992, Vol. 12, pp. 943–950).

[0251] 22.5 g of tetraethyl orthosilicate and 7.0 g of tetrapropylammonium hydroxide were mixed. 59.8 g of deionized water were added to the resulting mixture. The mixture was blended homogeneously and then hydrolyzed for 1.0 hour at 60°C to obtain a hydrolysis solution of tetraethyl orthosilicate. With vigorous stirring, a solution of 1.1 g of tetrabutyl titanate and 5.0 g of isopropyl alcohol was slowly and dropwise added to the above solution. The mixture was stirred for 3 hours at 75°C to produce a clear colloid, which was transferred to a closed stainless steel reaction vessel and crystallized at a constant temperature of 170°C for 3 days to produce a TS-1 molecular sieve. COMPARISON EXAMPLE 11

[0252] Production of HTS molecular sieve according to CN1102442C.

[0253] 22.5 g of tetraethyl orthosilicate and 9.0 g of tetrapropylammonium hydroxide were mixed. 64.5 g of deionized water were added to the resulting mixture. The mixture was blended homogeneously and then hydrolyzed for 1.0 hour at 60°C to obtain a hydrolysis solution of tetraethyl orthosilicate. With vigorous stirring, a solution of 0.6 g of tetrabutyl titanate and 7.0 g of isopropyl alcohol was slowly and dropwise added to the above solution. The mixture was stirred for 7 hours at 75°C to produce a clear colloid, which was transferred to a closed stainless steel reaction vessel and crystallized at a constant temperature of 170°C for 3 days to produce a TS-1 molecular sieve. Tetrabutyl titanate, anhydrous isopropyl alcohol, tetrapropylammonium hydroxide, and deionized water were blended homogeneously in a molar ratio of 1:15:2.4:350.The resulting mixture was hydrolyzed at normal pressure at 45°C for 30 minutes to produce a tetrabutyl titanate hydrolysis solution. The above TS-1 molecular sieve and the tetrabutyl titanate hydrolysis solution were homogeneously mixed in a ratio of molecular sieve (g):Ti(mol) = 600:1.

[0254] The mixture was stirred at normal temperature for 12 hours, then transferred to a stainless steel reaction vessel and held at 165°C for 3 days to produce the HTS molecular sieve. Measurement of the molecular sieve surface Si / Ti ratio using XPS etching.

[0255] The Ti-Si molecular sieve sample obtained in Example 1 was subjected to XPS etching (depth > 10 nm). Over time, the resulting Si / Ti ratio gradually decreased as an atom “in a pattern of a quadratic function curve with downward opening,” as shown in Fig. 13 shown.

[0256] The titanium silicalite molecular sieve samples obtained in Examples 2 to 33 were subjected to XPS etching (depth > 10 nm). Over time, the resulting Si / Ti ratio decreased gradually as an atom “in a pattern of a quadratic function curve with a downward opening”. ASSAYS

[0257] The following assay explains the effect of the samples from the examples and comparative examples in the production of dihydroxybenzene from phenol by oxidation-hydroxylation and in the production of cyclohexanone oxime from cyclohexanone by oxamidination.

[0258] The reagents used were commercially available and analytically pure. Concentrations before and after the reaction were measured by gas chromatography (GC, Agilent, 6890 model, FFAP column).

[0259] Phenol conversion, cyclohexanone conversion, and cyclohexanone oxime selectivity are calculated according to the following equations:

[0260] A 1.25 g sample of each example and control example was added to a three-necked flask containing 25 g of phenol and 20 mL of acetone. Once the temperature had stabilized at the set value, 9.81 g of H₂O₂ solution (at a concentration of 30 wt%) (molar ratio of phenol:H₂O₂ is 3) was added. The reaction was carried out under normal pressure (0.1 MPa) for 2 hours at 80°C (phenol was converted to dihydroxybenzene by hydroxylation). The sample was then collected.

[0261] Each sample from the examples and comparison samples was mixed with tert-butanol and 25 wt% aqueous ammonia in a molecular sieve ratio of tert-butanol:ammonia = 1:7.5:7.5 in a slurry bed. The temperature was raised to 75°C. At this temperature, 30 wt% H₂O₂ solution, a mixture of cyclohexanone and tert-butanol (cyclohexanone:tert-butanol = 1:2.5 v / v), and 15 wt% ammonia were added simultaneously at rates of 6 mL / h, 8.6 mL / h, and 6 mL / h, respectively. The three streams were taken from the reactor at the corresponding rates.

[0262] The catalyst loadings and LHSV (liquid hourly space velocity) for examples 1 to 9 and comparison examples 1 to 3 and 10 to 11 were 3.2 g and 6.4 h, respectively. –1 .

[0263] The catalyst loadings and LHSV (liquid hourly space velocity) for examples 12 to 20 and comparison examples 4 to 6 were 3 g and 6.9 h, respectively. –1 .

[0264] The catalyst loadings and LHSV (liquid hourly space velocity) for examples 23 to 31 and comparison examples 7 to 9 were 2.6 g and 7.92 h, respectively. –1 .

[0265] Once the reaction was stable, the samples were subjected to GC analysis and the results are shown in Table 3. H2O2 DECOMOSITION

[0266] 2 g of titanium silicalite molecular sieve were added to 15 g of H2O2 solution (30 wt%). The resulting mixture was stirred for 1 hour at 80°C. The concentration of the H2O2 solution was measured, and the result is shown in Table 3. Fig. 12 (Example 6 versus comparison example 11) shown. QUOTES INCLUDED IN THE DESCRIPTION

[0267] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0268] US 4410501

[0004] CN 1260241 A

[0004] CN 101798088 B

[0120] CN 1102442 C

[0252] Cited non-patent literature

[0269] Analytical Methods in Petrochemical Industry (RIPP Experiment Techniques), Yang Cuiding et al., Science Press, 1990

[0188] Zeolites, 1992, Vol. 12, pp. 943-950

[0250]

Claims

[1] Titanium silicalite molecular sieve, wherein the crystal grain of the titanium silicalite molecular sieve has a ratio of (surface Si / Ti ratio):(mass Si / Ti ratio) of greater than 1.1 and less than 5. [2] Titanium silicalite molecular sieve according to claim 1, wherein the ratio of (surface Si / Ti ratio):(mass Si / Ti ratio) is (1,2–4):

1. [3] Titanium silicalite molecular sieve according to claim 1, wherein the titanium silicalite molecular sieve has a Ti / Si molar ratio of (0.005–0.03):1, preferably (0.01–0.025):

1. [4] Titanium silicalite molecular sieve according to claim 1, wherein the titanium silicalite molecular sieve is a TS-1 molecular sieve, TS-2 molecular sieve or a Ti-β molecular sieve. [5] Titanium silicalite molecular sieve according to claim 1, wherein the crystal grain of the titanium silicalite molecular sieve has a hollow structure with a radial length of 5 to 300 nm for the cavity region of the hollow grain, the adsorption capacity of benzene, measured for the molecular sieve sample under the conditions of 25°C, P / P0 = 0.10 and 1 hour adsorption time is at least 70 mg / g and there is a hysteresis loop between the adsorption isotherm and the desorption isotherm for nitrogen adsorption by the molecular sieve at a low temperature. [6] Titanium silicalite molecular sieve according to claim 1, wherein the titanium silicalite molecular sieve has a micropore structure with a pore diameter of less than 1 nm and a mesopore structure with a diameter of 2 to 8 nm, wherein the volume of the pores with a pore diameter of 2 to 8 nm is 0.3 to 0.8 ml / g, and the volume of the pores with a pore diameter of less than 1 nm is 0.12 to 0.19 ml / g. [7] Titanium silicalite molecular sieve according to claim 1, wherein within a depth of 10 nm from the surface of the titanium silicalite molecular sieve to the interior of the titanium silicalite molecular sieve, the Si / Ti ratio, per atom, gradually decreases in a direction from the surface to the interior “in a pattern of a quadratic function curve with a downward opening”. [8] Method for the synthesis of a titanium silicalite molecular sieve, comprising the following steps: (1) a titanium source, a template agent, an organic silicon source, water and an optional inorganic amine source are mixed and subjected to hydrolysis and removal of alcohols; (2) the product obtained in step (1) is aged at 15 to 50°C; (3) The aged product obtained in step (2) and a solid silicon source are homogeneously mixed, then subjected to crystallization in a closed reaction vessel and the titanium silicalite molecular sieve is collected. [9] Method according to claim 8, wherein the titanium source is an organic titanium source and / or an inorganic titanium source; the template agent may be one or more compounds of an organic quaternary ammonium base, an organic amine, an organic quaternary ammonium salt, and a long-chain alkylammonium compound, wherein the molar ratio of the organic quaternary ammonium base to the total silicon source is zero or (0.05–0.36):1; the molar ratio of the organic amine to the total silicon source is (0–0.45):1; the molar ratio of the organic quaternary ammonium salt to the total silicon source is (0–0.45):1; and the molar ratio of the long-chain alkylammonium compound to the total silicon source is zero or (0.04–0.45):1; The organic silicon source is an organic silicate, which has a general formula Si(OR 1 )4 exhibits, wherein R 1 a linear or branched C 1-6 -Alkyl is; the solid silicon source is a silica particle or powder of high purity, wherein, on a dry basis and based on weight, the solid silicon source has a SiO2 content of more than 99.99 wt.% and a total atomic content of Fe, Al and Na of less than 10 ppm; the inorganic amine source is an inorganic ammonium salt and / or aqueous ammonia. [10] Method according to claim 8, wherein the molar ratio of the titanium source (as TiO2) to the total silicon source (as SiO2) is (0.005–0.05):1; the molar ratio of the template medium to the total silicon source (as SiO2) is (0.05–0.6):1; the molar ratio of water to the total silicon source (as SiO2) (5–100):1 is; the molar ratio of the inorganic amine source (as NH4) + ) to the titanium source (as TiO2) (0–5):1 is; The weight ratio of the aged product (as SiO2):the solid silicon source (as SiO2) is 1:(0.1–10). [11] Method according to claim 8, wherein the aging in step (2) is carried out by leaving the product at 15 to 50°C for 1 to 60 hours. [12] Method according to claim 8, wherein in step (3) the crystallization temperature is 110 to 200°C, the crystallization pressure is an autogenous pressure; and the crystallization time is 2 hours to 20 days. [13] Method according to claim 8, wherein in step (1) the template agent contains an organic quaternary ammonium base and / or an organic amine and optionally an organic quaternary ammonium salt. [14] Method according to claim 8, wherein in step (1) the template agent contains an organic quaternary ammonium base and / or an organic amine and optionally an organic quaternary ammonium salt, wherein the molar ratio of the organic quaternary ammonium base to the organic amine is 1:(0–10) and the molar ratio of the organic quaternary ammonium base to the organic quaternary ammonium salt is 1:(0–10). [15] Method according to claim 8, wherein in step (1) the template agent contains an organic quaternary ammonium salt and an organic base. [16] Method according to claim 8, wherein in step (1) the template agent contains an organic quaternary ammonium salt and an organic base, wherein the molar ratio of the organic quaternary ammonium salt to the total silicon source is (0.04–0.55):1, the molar ratio of the organic quaternary ammonium base to the total aluminum salt is (0.04–0.45):1, and the molar ratio of the inorganic amine source (as NH4) is + ) to the titanium source (as TiO2) (0–0.5):1 is. [17] Method according to claim 8, wherein in step (1) the template agent comprises an organic quaternary ammonium base and / or an organic quaternary ammonium salt, an optional organic amine and a long-chain alkylammonium compound. [18] Method according to claim 8, wherein in step (1) the template agent comprises an organic quaternary ammonium base and / or an organic quaternary ammonium salt, an optional organic amine and a long-chain alkylammonium compound, wherein the molar ratio of the (organic quaternary ammonium base and the organic quaternary ammonium salt) to the total silicon source is (0.04–0.45):1 and the molar ratio of the long-chain alkylammonium compound to the total silicon source is (0.04–0.45):

1. [19] Method according to claim 8, wherein the template agent is selected from the group consisting of: (1) an organic quaternary ammonium base and optionally a long-chain alkylammonium compound; (2) an organic quaternary ammonium salt, an organic amine and optionally a long-chain alkylammonium compound; (3) an organic quaternary ammonium salt and a long-chain alkylammonium compound. [20] The method of claim 8, wherein the titanium silicalite molecular sieve is a TS-1 molecular sieve, wherein the template agent is one or more of tetrapropylammonium hydroxide, tetrapropylammonium chloride and tetrapropylammonium bromide, and optionally with an organic amine and / or a long-chain alkylammonium compound; or the titanium silicalite molecular sieve is a TS-2 molecular sieve, wherein the template agent is one or more of tetrapropylammonium hydroxide, tetrapropylammonium chloride and tetrapropylammonium bromide, and optionally with an organic amine and / or a long-chain alkylammonium compound; or the titanium silicalite molecular sieve is a Ti-β molecular sieve, wherein the template agent is one or more of tetrapropylammonium hydroxide, tetrapropylammonium chloride and tetrapropylammonium bromide, and optionally with an organic amine and / or a long-chain alkylammonium compound. [21] The method of claim 8, wherein the method further comprises a step (4): the titanium silicalite molecular sieve obtained in step (3) is subjected to crystallization in an organic base solution and then the titanium silicalite molecular sieve is collected; the crystallization temperature may be 100 to 200°C or 100 to 150°C or 120 to 200°C or 150 to 200°C; the crystallization time may be 0.1 to 10 days or 0.5 to 10 days or 0.5 to 8 days or 0.5 to 6 days or 1 to 6 days; in step (4) the molar ratio of the titanium silicalite molecular sieve to the organic base may be 1:(0.02–0.5) or 1:(0.02–0.2); The molar ratio of the titanium silicalite molecular sieve to water can be 1:(2–50), 1:(2–30), 1:(2–20) or 1:(5–10). [22] Method according to claim 8, wherein the titanium source is one or more of tetraalkyl titanate (Ti(alkoxy)4), TiCl4, Ti(SO4)2 and hydrolysates thereof, wherein the alkyl group in the tetraalkyl titanate contains 1 to 6 carbon atoms. [23] Method according to claim 8, wherein the solid silicon source is white carbon with a specific surface area of ​​50 to 400 m² 2 / g is. [24] Method according to claim 8, wherein the molar ratio of the titanium source (as TiO2) to the total silicon source (as SiO2) is (0.005–0.040):1; (0.010–0.030):1; or (0.010–0.025):

1. [25] Method according to claim 8, wherein the molar ratio of the template agent to the total silicon source (as SiO2) is (0.05–0.30):1; (0.05–0.25):1; (0.05–0.20):1; (0.05–0.5):1; or (0.08–0.6):

1. [26] Method according to claim 8, wherein the molar ratio of water to the total silicon source (as SiO2) is (5–50):1; (6–30):1; or (6–15):

1. [27] Method according to claim 8, wherein the molar ratio of the inorganic amine source (as NH4) + ) to the titanium source (as TiO2) (0.01–4):1 or (0.05–0.5):

1. [28] Method according to claim 8, wherein the molar ratio of the inorganic amine source (as NH4) + ) to the total silicon source (as SiO2) (0.01–0.07):1 or (0.01–0.05):

1. [29] Method according to claim 8, wherein the weight ratio of the aged product (as SiO2) to the total silicon source (as SiO2) is 1:(1–9) or 1:(2–8). [30] Method according to claim 8, wherein the organic quaternary ammonium base is one or more of tetrapropylammonium hydroxide (TPAOH), tetrabutylammonium hydroxide (TBAOH) and tetraethylammonium hydroxide (TEAOH); the organic amine may be one or more of an aliphatic amine, aromatic amine and alcoholic amine; the aliphatic amine a general formula R 3 (NH2) nmay have, in which R 3 C 1-4 -Alkyl or C 1-4 -Alkylene is, n 1 or 2 is; for example, one or more of ethylamine, n-butylamine, butylenediamine and hexamethylenediamine; the alcoholic amine a general formula (HOR 4 ) m NH (3-m) may have, in which R 4 C 1-4 -Alkyl is, m 1, 2 or 3 is; for example, one or more of monoethanolamine, diethanolamine and triethanolamine; the aromatic amine may be one or more of aniline, aminotoluene and p-phenylenediamine; the organic quaternary ammonium salt may be one or more of tetrapropylammonium bromide, tetrabutylammonium bromide, tetraethylammonium bromide, tetrapropylammonium chloride, tetrabutylammonium chloride and tetraethylammonium chloride; the long-chain alkylammonium compound has the formula R 5 NH3X or R 5 N(R 6 )3X can have, in which R 5 C 1-8-Alkyl is, R 6 C 1-6 -Alkyl is (e.g., C 1-4 -Alkyl), wherein three R 6 in R 5 N(R 6 )3X may or may not be identical; X a monovalent anion, e.g. OH – , Cl – , Br – is; e.g., one or more of long-chain alkyltrimethylammonium chloride, long-chain alkyltrimethylammonium bromide, and long-chain alkyltrimethylammonium hydroxide; e.g., cetyltrimethylammonium bromide (CTMAB), cetyltrimethylammonium chloride, cetyltrimethylammonium hydroxide (MSDS), the long-chain alkylammonium compound being one or more of myristyltrimethylammonium bromide (TTAB), myristyltrimethylammonium chloride, myristyltrimethylammonium hydroxide, dodecyltrimethylammonium bromide (DTAB), dodecyltrimethylammonium chloride, dodecyltrimethylammonium hydroxide, octadecyltrimethylammonium bromide, octadecyltrimethylammonium chloride, octadecyltrimethylammonium hydroxide. [31] Method according to claim 8, wherein in step (1) the time for hydrolysis and removal of alcohols is at least 10 minutes, e.g. 2 to 30 hours. [32] Method according to claim 8, wherein in step (1) the temperature for the hydrolysis and removal of alcohols is 0 to 150°C, e.g. 50 to 95°C. [33] Method according to claim 8, wherein in the mixture obtained in step (1) the weight content of the alcohols produced by hydrolyzing the organic silicon source and the titanium source is not higher than 10 ppm. [34] Method according to claim 8, wherein in step (2) the aging time is 2 to 50 hours or 3 to 30 hours or 3 to 15 hours or 1 to 60 hours. [35] Method according to claim 8, wherein in step (2) the aging temperature is room temperature up to 50°C or 15 to 30°C or 15 to 26°C or 26 to 30°C. [36] Method according to claim 8, wherein in step (3) the crystallization temperature is 110 to 200°C, 140 to 180°C or 160 to 180°C. [37] Method according to claim 8, wherein in step (3) the crystallization time is 2 hours to 20 days, 0.5 to 20 days, 0.5 to 10 days or 1 to 6 days or 0.5 to 6 days or 0.5 to 3 days or 1 to 3 days. [38] Method according to claim 8, wherein in step (3) the crystallization pressure is an autogenous pressure. [39] Method according to claim 8, wherein in step (3) the crystallization is carried out under the following conditions: the crystallization is carried out at 100 to 130°C, e.g. at 110 to 130°C for 0.5 to 1.5 days and then at 160 to 180°C for 1 to 3 days and the crystallization pressure is an autogenous pressure. [40] Method according to claim 8, wherein the organic silicate is one or more of tetramethyl orthosilicate, tetraethyl orthosilicate, tetrabutyl orthosilicate and dimethyl diethyl orthosilicate.