CN112744836A

CN112744836A - Titanium-silicon molecular sieve, preparation method thereof and method for producing ketoxime by macromolecular ketone ammoximation reaction

Info

Publication number: CN112744836A
Application number: CN201911054988.9A
Authority: CN
Inventors: 杨永佳; 朱斌; 夏长久; 林民; 刘聿嘉; 厉晨豪; 罗一斌; 舒兴田
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2019-10-31
Filing date: 2019-10-31
Publication date: 2021-05-04
Anticipated expiration: 2039-10-31
Also published as: CN112744836B

Abstract

The invention relates to a titanium-silicon molecular sieve, a preparation method thereof and a method for producing ketoxime by macromolecular ketone ammoximation reaction, wherein the titanium-silicon molecular sieve consists of oxygen element, silicon element and titanium element, and TiO of the titanium-silicon molecular sieve is calculated by oxide and calculated by molar weight₂With SiO₂In a molar ratio of 1: (25-100); the ratio of the surface titanium-silicon ratio of the titanium-silicon molecular sieve to the bulk phase titanium-silicon ratio is 1.7-3.9, wherein the titanium-silicon ratio refers to TiO₂With SiO₂The molar ratio of (A) to (B); when the titanium-silicon molecular sieve is subjected to BET nitrogen adsorption and desorption test, p/p₀Adsorption capacity and p/p of titanium silicalite molecular sieve of 0.8₀The difference of the adsorption capacity of the titanium silicalite molecular sieve at 0.2 is recorded as delta V, and the delta V is 26more than mL/g. The titanium silicalite molecular sieve disclosed by the invention is rich in titanium on the surface, has rich open pores and high catalytic activity, and is favorable for improving the conversion rate of raw materials and the selectivity of target products when being used in a process for producing ketoxime by a macromolecular ketone ammoximation reaction.

Description

Titanium-silicon molecular sieve, preparation method thereof and method for producing ketoxime by macromolecular ketone ammoximation reaction

Technical Field

The invention relates to a titanium-silicon molecular sieve, a preparation method thereof and a method for producing ketoxime by macromolecular ketone ammoximation reaction.

Background

The titanium-silicon molecular sieve is a novel heteroatom molecular sieve developed in the beginning of the eighties of the 20 th century and refers to a class of heteroatom molecular sieves containing framework titanium. The microporous titanium silicalite molecular sieves synthesized at present comprise TS-1(MFI structure), TS-2(MEL structure), Ti-Beta (BEA structure), Ti-ZSM-12(MTW structure), Ti-MCM-22(MWW structure) and the like, and the mesoporous titanium silicalite molecular sieves comprise Ti-MCM-41, Ti-SBA-15 and the like. The development and application of the titanium-silicon molecular sieve successfully expand the zeolite molecular sieve from the acid catalysis field to the catalytic oxidation field, and have milestone significance. Of these, Enichem, Italy, first published TS-1 in 1983 as the most representative titanium silicalite molecular sieve. TS-1 has MFI topology with a two-dimensional ten-membered ring channel system, which [100 ]]The direction is a straight channel with a pore diameter of 0.51X 0.55nm, [010]The direction is sinusoidal channels with pore diameter of 0.53 x 0.56 nm. Due to the introduction of Ti atoms and the special pore channel structure, TS-1 and H₂O₂The formed oxidation system has the advantages of mild reaction conditions, green and environment-friendly oxidation process, good selectivity of oxidation products and the like in the oxidation reaction of organic matters.At present, the catalytic oxidation system can be widely applied to reactions such as alkane oxidation, olefin epoxidation, phenol hydroxylation, ketone (aldehyde) ammoximation, oil oxidation desulfurization and the like, wherein industrial application is successively realized in phenol hydroxylation, ketone (cyclohexanone, butanone and acetone) ammoximation and propylene epoxidation.

The US patent 4410501 first discloses a method for synthesizing a titanium silicalite TS-1 by a classical hydrothermal crystallization method. The method is mainly carried out by two steps of glue preparation and crystallization, and comprises the following specific steps: putting silicon source Tetraethoxysilane (TEOS) into nitrogen to protect CO₂Slowly adding template tetrapropylammonium hydroxide (TPAOH), slowly dropwise adding titanium source tetraethyl titanate (TEOT), stirring for 1h to prepare a reaction mixture containing silicon, titanium and organic alkali, heating, removing alcohol, replenishing water, crystallizing for 10 days at 175 ℃ under the stirring of an autogenous pressure kettle, separating, washing, drying and roasting to obtain the TS-1 molecular sieve. However, in the process, factors influencing insertion of titanium into the framework are numerous, conditions of hydrolysis, crystallization nucleation and crystal growth are not easy to control, a certain amount of titanium cannot be effectively inserted into the molecular sieve framework and is retained in a pore channel in a non-framework titanium form, the generation of non-framework titanium not only reduces the number of catalytic active centers, but also promotes ineffective decomposition of hydrogen peroxide by non-framework titanium silicon species to cause raw material waste, so that the TS-1 molecular sieve synthesized by the method has the defects of low catalytic activity, poor stability, difficulty in reproduction and the like.

In the preparation method of titanium silicalite TS-1(Zeolite, 1992, Vol.12, pages 943-950) disclosed by Thangaraj et al, in order to effectively improve the insertion of titanium into a molecular sieve framework, a strategy of hydrolyzing organic silicone grease firstly and then slowly dripping organic titanate for hydrolysis is adopted, the hydrolysis speed of organic silicon and titanium is matched, and isopropanol is introduced in the hydrolysis process of titanium, however, the titanium silicalite TS-1 obtained by the method is limited in the aspect of improving the content of framework titanium, a certain amount of non-framework titanium such as anatase still exists, and the catalytic activity is not high.

CN1301599A discloses a method for preparing a novel hollow titanium silicalite molecular sieve HTS with a hollow structure and less non-framework titanium, which comprises the steps of uniformly mixing a synthesized TS-1 molecular sieve, an acidic compound and water, reacting for 5 minutes to 6 hours at 5 to 95 ℃ to obtain an acid-treated TS-1 molecular sieve, uniformly mixing the acid-treated TS-1 molecular sieve, an organic base and the water, putting the obtained mixture into a sealed reaction kettle, and reacting for 1 hour to 8 days at the temperature of 120 to 200 ℃ and the autogenous pressure. The molecular sieve has less non-framework titanium and better catalytic oxidation activity and stability.

Disclosure of Invention

The titanium silicalite molecular sieve is rich in titanium on the surface and has rich open pores, and can improve the conversion rate of raw materials and the selectivity of target products when being used in the process of producing ketoxime by the ammoximation reaction of macromolecular ketones.

In order to achieve the above objects, the present disclosure provides a titanium silicalite molecular sieve, which is composed of an oxygen element, a silicon element and a titanium element, and the titanium silicalite molecular sieve is TiO in terms of oxides and molar weight₂With SiO₂In a molar ratio of 1: (25-100); the ratio of the surface titanium-silicon ratio of the titanium-silicon molecular sieve to the bulk phase titanium-silicon ratio is 1.7-3.9, wherein the titanium-silicon ratio refers to TiO₂With SiO₂The molar ratio of (A) to (B); when the titanium-silicon molecular sieve is subjected to BET nitrogen adsorption and desorption test, p/p₀The adsorption capacity and p/p of the titanium silicalite molecular sieve is 0.8₀When the adsorption capacity of the titanium silicalite molecular sieve is 0.2, the difference of the adsorption capacity is recorded as delta V, and the delta V is more than 26 mL/g.

Alternatively, Δ V is 26-60mL/g, preferably 26-55 mL/g.

Optionally, the titanium silicalite molecular sieve has a BET total specific surface area of 400-²The ratio of the mesoporous volume to the total pore volume is 50-70%.

Optionally, the titanium silicalite molecular sieve has an intragranular multiple hollow structure.

In a second aspect of the present disclosure, a method of making a titanium silicalite molecular sieve comprises:

a. mixing a first structure directing agent, a first silicon source, a first titanium source and water, and then carrying out first hydrolysis for 0.5-30 hours at 40-97 ℃ to obtain a first hydrolysis mixture;

b. mixing the first hydrolysis mixture with a carbon-containing porous material, performing first hydrothermal treatment for 1-600 hours at 90-200 ℃ in a pressure-resistant closed container, and collecting a first solid product;

c. mixing a second structure directing agent, a second silicon source, a second titanium source and water, and performing second hydrolysis at 35-95 ℃ for 0.5-40 hours to obtain a second hydrolysis mixture;

d. mixing the first solid product, the second hydrolysis mixture and an optional inorganic ammonium source to obtain a mixed material, carrying out second hydrothermal treatment on the mixed material in a pressure-resistant closed container at 90-200 ℃ for 1-168 hours, collecting a second solid product, drying and roasting;

wherein the molar ratio of the first titanium source to the first silicon source is smaller than the molar ratio of the second titanium source to the second silicon source, and the first silicon source and the second silicon source are made of SiO₂The first titanium source and the second titanium source are calculated as TiO₂And (6) counting.

Optionally, the carbon-containing porous material is carbon nano tube, carbon nano fiber, cracked carbon black or semi-coke-based activated carbon, or a combination of two or three of the carbon nano fiber, the cracked carbon black and the semi-coke-based activated carbon; preferably, the carbon-containing porous material is carbon nano tube and/or semi-coke-based activated carbon.

Optionally, the first structure directing agent and the second structure directing agent are each independently a quaternary ammonium base compound;

the quaternary ammonium base compound is tetraethylammonium hydroxide, tetrapropylammonium hydroxide or tetrabutylammonium hydroxide.

Optionally, the first structure directing agent and the second structure directing agent are each independently a mixture of a quaternary ammonium salt compound and one or more of a quaternary ammonium base compound, a fatty amine compound, an alcohol amine compound, and an aromatic amine compound;

the quaternary ammonium base compound is tetrapropylammonium hydroxide, and the quaternary ammonium salt compound is tetrapropylammonium chloride and/or tetrapropylammonium bromide; or,

the quaternary ammonium base compound is tetrabutylammonium hydroxide, and the quaternary ammonium salt compound is tetrabutylammonium chloride and/or tetrabutylammonium bromide; or,

the quaternary ammonium base compound is tetraethylammonium hydroxide, and the quaternary ammonium salt compound is tetraethylammonium chloride and/or tetraethylammonium bromide.

Optionally, the fatty amine compound is ethylamine, n-butylamine, butanediamine, or hexamethylenediamine, or a combination of two or three thereof;

the alcohol amine compound is monoethanolamine, diethanolamine or triethanolamine, or a combination of two or three of the monoethanolamine, diethanolamine and triethanolamine;

the aromatic amine compound is aniline, toluidine or p-phenylenediamine, or a combination of two or three of them.

Optionally, in step a, the molar ratio of the amounts of the first structure directing agent, the first silicon source, the first titanium source and water is (0.05-1.5): 1: (0.001-0.05): (10-400), preferably (0.1-0.8): 1: (0.005-0.02): (30-200), wherein the first silicon source is SiO₂The first titanium source is calculated as TiO₂And (6) counting.

Optionally, the first silicon source and the second silicon source are each an organic silicone grease, preferably, the first silicon source and the second silicon source are each independently tetramethyl orthosilicate, tetraethyl orthosilicate, tetrapropyl orthosilicate, tetrabutyl orthosilicate, or dimethoxydiethoxysilane, or a combination of two or three of them;

the first titanium source and the second titanium source are each independently an inorganic titanium salt and/or an organic titanate.

Optionally, the carbon-containing porous material in step b is used in an amount of 0.001-0.5 molar parts relative to 1 molar part of the first silicon source, which is SiO₂The carbon-containing porous material is calculated by carbon element;

preferably, the carbonaceous porous material is used in an amount of 0.005 to 0.3 molar parts with respect to 1 molar part of the first silicon source.

Optionally, in step a, the temperature of the first hydrolysis is 65-95 ℃ and the time is 1-15 hours; and/or the like and/or,

in the step b, the temperature of the first hydrothermal treatment is 120-180 ℃, and the time is 5-480 hours.

Optionally, in step c, the molar ratio of the second structure directing agent, the second silicon source, the second titanium source and the water is (1.5-5): (10-80): 1: (400-1000), the second silicon source is SiO₂The second titanium source is calculated as TiO₂And (6) counting.

Optionally, in step c, the temperature of the second hydrolysis is 50-95 ℃ and the time is 1-12 hours.

Optionally, in step d, the inorganic ammonium source is ammonium chloride, ammonium sulfate, ammonium oxalate, ammonium carbonate or aqueous ammonia, or a combination of two or three thereof.

Optionally, in step d, TiO in the mixed material₂、SiO₂And NH₄ ⁺In a molar ratio of 1: (10-200): (0-4), preferably, TiO₂、SiO₂And NH₄ ⁺In a molar ratio of 1: (20-100): (0.1-0.8).

Optionally, in the step d, the temperature of the second hydrothermal treatment is 130-.

Optionally, in the step d, the drying temperature is 100-200 ℃, and the drying time is 1-24 hours; the roasting temperature is 350-650 ℃ and the roasting time is 1-6 hours.

A third aspect of the present disclosure provides a titanium silicalite molecular sieve prepared using the method provided by the second aspect of the present disclosure.

A fourth aspect of the present disclosure provides a catalyst comprising a titanium silicalite molecular sieve as provided in the first or third aspect of the present disclosure.

In a fifth aspect of the present disclosure, a method for producing ketoxime by a macromolecular ketone ammoximation reaction is provided, wherein the method uses the catalyst provided by the fourth aspect of the present disclosure.

Optionally, the macromolecular ketone is cyclohexanone, cyclopentanone, cyclododecanone, or acetophenone.

By the technical scheme, the titanium-silicon molecular sieve disclosed by the invention is rich in titanium on the surface, has a wide pore structure and high catalytic activity, is favorable for improving the conversion rate of raw materials and the selectivity of a target product when being used in a process for producing ketoxime by a macromolecular ketone ammomacroketone ammoximation reaction, and is particularly suitable for a acetophenone ammoximation reaction.

Additional features and advantages of the disclosure will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:

FIG. 1 is an XRD spectrum of a titanium silicalite molecular sieve prepared in example 1 of the present disclosure;

FIG. 2 is a TEM electron micrograph of a titanium silicalite molecular sieve prepared in example 1 of the present disclosure;

FIG. 3 is a TEM-EDX electron micrograph of a titanium silicalite molecular sieve prepared in example 1 of the present disclosure;

fig. 4 is a low temperature nitrogen adsorption-desorption graph of the intermediate titanium silicalite molecular sieve prepared in example 1 of the present disclosure.

Detailed Description

The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.

The first aspect of the present disclosure provides a titanium silicalite molecular sieve, which is composed of oxygen element, silicon element and titanium element, and calculated by oxide and molar weight, TiO of the titanium silicalite molecular sieve₂With SiO₂In a molar ratio of 1: (25-100); the ratio of the surface titanium-silicon ratio of the titanium-silicon molecular sieve to the bulk phase titanium-silicon ratio is 1.7-3.9, wherein the titanium-silicon ratio refers to TiO₂With SiO₂The molar ratio of (A) to (B); when the titanium-silicon molecular sieve is subjected to BET nitrogen adsorption and desorption test, p/p₀Adsorption capacity and p/p of titanium silicalite molecular sieve of 0.8₀When the adsorption capacity of the titanium silicalite molecular sieve is 0.2, the difference is recorded as delta V, and the delta V is more than 26 mL/g.

Wherein, p/p₀It means that in the BET nitrogen adsorption and desorption test, the nitrogen partial pressure and the liquid nitrogen saturation at the adsorption temperatureAnd the vapor pressure. According to the present disclosure, the titanium silicalite molecular sieve is an MFI-type titanium silicalite molecular sieve, an MEL-type titanium silicalite molecular sieve, or a BEA-type titanium silicalite molecular sieve. The titanium silicalite molecular sieve disclosed by the invention is rich in titanium on the surface, has a wide pore structure and is high in catalytic activity.

In the present disclosure, the BET nitrogen adsorption and desorption test may be performed according to a conventional method, and the present disclosure does not specifically limit this. Surface titanium to silicon ratio refers to the atomic layer of TiO not more than 5nm (e.g., 1-5nm) from the surface of the titanium silicalite molecular sieve grains₂With SiO₂The bulk titanium-silicon ratio of (A) means SiO of the whole molecular sieve crystal grains₂With TiO₂In a molar ratio of (a). The surface titanium-silicon ratio and the bulk titanium-silicon ratio can be determined by methods conventionally adopted by those skilled in the art, for example, the TiO of the edge and central target point of the titanium-silicon molecular sieve can be determined by a transmission electron microscope-energy dispersive X-ray spectroscopy (TEM-EDX) method₂With SiO₂Molar ratio, TiO at edge targets₂With SiO₂TiO with the molar ratio of surface titanium to silicon and a central target point₂With SiO₂The molar ratio is the bulk phase titanium-silicon ratio. Alternatively, the surface titanium-silicon ratio can be determined by ion-excited etching X-ray photoelectron spectroscopy (XPS), and the bulk titanium-silicon ratio can be determined by chemical analysis or by X-ray fluorescence spectroscopy (XRF).

Preferably, Δ V is 26-60mL/g, more preferably 26-55 mL/g.

According to the present disclosure, the BET total specific surface area of the titanium silicalite molecular sieve can be 400-600m²The volume ratio of the mesoporous volume to the total pore volume can be 50-70%. Preferably, the BET total specific surface area is 450-²The volume ratio of the mesoporous volume to the total pore volume is 55-65%. The BET total specific surface area and pore volume measurements in the present disclosure may be made according to conventional methods, and are not specifically limited in this disclosure and are well known to those skilled in the art, for example, using the BET nitrogen adsorption and desorption test method. The particle size of the molecular sieve may be measured by conventional methods, such as by a laser particle size analyzer, and the specific test conditions may be those routinely employed by those skilled in the art.

According to the disclosure, the titanium silicalite molecular sieve can have an intragranular multi-hollow structure, improves the diffusion performance of the titanium silicalite molecular sieve, is favorable for improving the conversion rate of raw materials and the selectivity of a target product when used for the catalytic reaction of a macromolecular raw material, and is particularly suitable for the acetophenone ammoximation reaction.

A second aspect of the present disclosure provides a method of preparing a titanium silicalite molecular sieve, the method comprising:

wherein, the molar ratio of the first titanium source to the first silicon source is less than that of the second titanium source to the second silicon source, and the first silicon source and the second silicon source are made of SiO₂The first titanium source and the second titanium source are calculated as TiO₂And (6) counting.

The titanium silicalite molecular sieve is prepared by adopting a two-step hydrothermal process, the surface of the prepared titanium silicalite molecular sieve is rich in titanium and has an open pore structure, the utilization rate of a Ti active center is effectively improved, and the titanium silicalite molecular sieve is favorable for improving the conversion rate of raw materials and the selectivity of a target product when being used for the catalytic reaction of a macromolecular raw material, and is particularly suitable for a acetophenone ammoximation reaction.

According to the present disclosure, the carbon-containing porous material may be a carbon-containing porous material having a surface layer structure rich in hydroxyl groups and uniform micropores, and may be, for example, a carbon nanotube, a carbon nanofiber, a pyrolysis carbon black, or a semi-coke-based activated carbon, or may be themOr a combination of two or three thereof. Wherein the semi-coke-based activated carbon is an activated carbon material with uniform micropores, which is prepared by an activation method combining chemical etching and physical dredging with semi-coke, the surface structure of the activated carbon material is rich in hydroxyl, and the specific surface area is 300-1000m²(iv)/g, median pore diameter of 0.3-20 nm. Preferably, the carbon-containing porous material is carbon nano tube and/or semi-coke-based activated carbon.

In accordance with the present disclosure, the structure directing agent can be a common type of synthetic titanium silicalite molecular sieve, and in one embodiment, the first structure directing agent and the second structure directing agent can each independently be a quaternary ammonium base compound. In another embodiment, the first structure directing agent and the second structure directing agent may each independently be a mixture of a quaternary ammonium salt compound and one or more of a quaternary ammonium base compound, a fatty amine compound, an alcohol amine compound, and an aromatic amine compound.

According to one embodiment of the present disclosure, the first structure directing agent and the second structure directing agent may be tetrapropylammonium hydroxide, or may be a mixture of tetrapropylammonium chloride and/or tetrapropylammonium bromide and one or more selected from quaternary ammonium base compounds, aliphatic amine compounds, alcohol amine compounds and aromatic amine compounds, respectively, and the synthesized titanium silicalite molecular sieve is a TS-1 molecular sieve. Further, when the structure directing agent is a mixture of tetrapropylammonium chloride and/or tetrapropylammonium bromide and one or more selected from the group consisting of a quaternary ammonium base compound, a fatty amine compound, an alcohol amine compound, and an aromatic amine compound, the molar ratio of tetrapropylammonium chloride and/or tetrapropylammonium bromide to one or more of the quaternary ammonium base compound, the fatty amine compound, the alcohol amine compound, and the aromatic amine compound may be 1: (0.1-5).

In another embodiment, the first structure directing agent and the second structure directing agent may be tetrabutylammonium hydroxide, respectively, or may be a mixture of tetrabutylammonium chloride and/or tetrabutylammonium bromide and one or more selected from the group consisting of a quaternary ammonium base compound, a fatty amine compound, an alcohol amine compound, and an aromatic amine compound, each independently. At this time, the synthesized titanium silicalite molecular sieve is a TS-2 molecular sieve. Further, when the structure directing agent is a mixture of tetrabutylammonium chloride and/or tetrabutylammonium bromide and one or more selected from the group consisting of a quaternary ammonium base compound, a fatty amine compound, an alcohol amine compound, and an aromatic amine compound, the molar ratio of tetrabutylammonium chloride and/or tetrabutylammonium bromide to one or more of the quaternary ammonium base compound, the fatty amine compound, the alcohol amine compound, and the aromatic amine compound may be 1: (0.2-7).

In another embodiment, the first structure directing agent and the second structure directing agent may each be tetraethylammonium hydroxide, or may each independently be a mixture of tetraethylammonium chloride and/or tetraethylammonium bromide with one or more compounds selected from quaternary ammonium base compounds, fatty amine compounds, alcohol amine compounds, and aromatic amine compounds. At this time, the synthesized titanium-silicon molecular sieve is a Ti-beta molecular sieve. Further, when the structure directing agent is a mixture of one or more selected from the group consisting of tetraethylammonium chloride and/or tetraethylammonium bromide and one or more selected from the group consisting of quaternary ammonium base compounds, fatty amine compounds, alcohol amine compounds, and aromatic amine compounds, the molar ratio of tetraethylammonium chloride and/or tetraethylammonium bromide to one or more of the quaternary ammonium base compounds, fatty amine compounds, alcohol amine compounds, and aromatic amine compounds may be 1: (0.07-8).

According to the present disclosure, the fatty amine compound has the general formula R₅(NH₂)_nWherein R is₅Is C1-C4 alkyl or C1-C4 alkylene, and n is 1 or 2. Preferably, the fatty amine compound may be ethylamine, n-butylamine, butanediamine or hexamethylenediamine, or a combination of two or three thereof.

According to the present disclosure, the alcohol amine compound has the general formula (HOR)₆)_mNH₍₃-m), wherein R₆Is C1-C4 alkyl, and m is 1, 2 or 3. Preferably, the alkanolamine compound may be monoethanolamine, diethanolamine or triethanolamine, or a combination of two or three thereof.

According to the present disclosure, the aromatic amine compound may be an amine having one aromatic substituent. Preferably, the aromatic amine compound may be aniline, toluidine or p-phenylenediamine, or a combination of two or three thereof.

According to the present disclosure, in step a, the molar ratio of the amounts of the first structure directing agent, the first silicon source, the first titanium source and water may be (0.05-1.5): 1: (0.001-0.05): (10-400), wherein the first silicon source is SiO₂The first titanium source is calculated as TiO₂And (6) counting. Preferably, the molar ratio of the amounts of the first structure directing agent, the first silicon source, the first titanium source and water is (0.1-0.8): 1: (0.005-0.02): (30-200).

The first and second silicon sources may be those commonly used for synthesizing titanium silicalite molecular sieves well known to those skilled in the art in light of the present disclosure, and the present disclosure is not particularly limited thereto. In one embodiment, the first silicon source and the second silicon source may be organic silicone grease, and preferably, the first silicon source and the second silicon source may be tetramethyl orthosilicate, tetraethyl orthosilicate, tetrapropyl orthosilicate, tetrabutyl orthosilicate or dimethoxydiethoxysilane, or a combination of two or three of them, independently.

The first and second titanium sources may be conventional in the art in light of this disclosure. Preferably, the first and second titanium sources may each independently be an inorganic titanium salt and/or an organic titanate, for example the inorganic titanium salt may be titanium tetrachloride, titanium sulfate or titanium nitrate, or a hydrolysate of titanium tetrachloride, titanium sulfate or titanium nitrate; the organic titanate may be ethyl titanate, tetrapropyl titanate or tetrabutyl titanate.

According to the present disclosure, the temperature of the first hydrolysis in step a is preferably 65 to 95 ℃ and the time is preferably 1 to 15 hours. Both the mixing and the first hydrolysis may be carried out under stirring in order to obtain the desired effect. After the first hydrolysis, the alcohol generated by the hydrolysis of the first titanium source and the first silicon source in the reaction system may be removed to obtain the first hydrolysis mixture. The present disclosure is not particularly limited in the manner and conditions for removing the alcohol, and any known suitable manner and conditions may be used, for example, the alcohol may be removed from the reaction system by azeotropic distillation and water lost by azeotropic distillation may be replenished.

According to the present disclosure, step (ii) is performed relative to 1 molar part of the first silicon sourceThe amount of the carbon-containing porous material used in step b may be 0.001 to 0.5 molar parts, preferably 0.005 to 0.3 molar parts, wherein the first silicon source is SiO₂The carbon-containing porous material is calculated by carbon element.

According to the present disclosure, the temperature of the first hydrothermal treatment in step b is preferably 120-. The pressure of the first hydrothermal treatment is not particularly limited, and may be the autogenous pressure of the reaction system.

According to the present disclosure, in step c, preferably, the molar ratio of the amounts of the second structure directing agent, the second silicon source, the second titanium source and water may be (1.5-5): (10-80): 1: (400-1000), the second silicon source is SiO₂The second titanium source is calculated as TiO₂And (6) counting.

According to the present disclosure, in step c, preferably, the temperature of the second hydrolysis is preferably 50 to 95 ℃ and the time is preferably 1 to 12 hours. Both mixing and the second hydrolysis may be carried out under stirring in order to obtain the desired effect.

According to the present disclosure, in step d, the inorganic ammonium source may be ammonium chloride, ammonium sulfate, ammonium oxalate, ammonium carbonate or aqueous ammonia, or a combination of two or three thereof.

According to the present disclosure, the temperature of the second hydrothermal treatment in step d is preferably 130-190 ℃ and the time is preferably 5-96 hours. The pressure of the second hydrothermal treatment is not particularly limited, and may be the autogenous pressure of the reaction system. In the step d, the obtained second solid product is dried and roasted to obtain the titanium silicalite molecular sieve. Preferably, the second solid product may be filtered, washed (optionally) and then dried and calcined. The filtration method is not particularly limited, for example, a suction filtration method can be adopted, and a washing method is not particularly limited, for example, mixed washing or rinsing can be carried out at room temperature to 50 ℃ by using water, and the water amount can be 1-20 times of the mass of the solid product. According to the present disclosure, the temperature of drying and baking can vary within a wide range, preferably, the temperature of drying can be 100-; the temperature for calcination can be 350-650 deg.C, and the time can be 1-6 hours.

According to the bookDiscloses that TiO in the mixed material of the step d₂、SiO₂And NH₄ ⁺May be 1: (10-200): (0-4), preferably, TiO₂、SiO₂And NH₄ ⁺In a molar ratio of 1: (20-100): (0.1-0.8).

According to the present disclosure, the temperature rising manner in any of the above steps is not particularly limited, and a temperature rising program manner, such as 0.5-1 ℃/min, may be adopted.

A fourth aspect of the present disclosure provides a catalyst comprising a catalyst provided by the first aspect of the present disclosure or a titanium silicalite provided by the third aspect of the present disclosure.

In one embodiment, the macromolecular ketone is cyclohexanone, cyclopentanone, cyclododecanone, or acetophenone.

The present disclosure is further illustrated by the following examples, but is not to be construed as being limited thereby.

In the examples and comparative examples, the surface titanium-silicon ratio and bulk titanium-silicon ratio of the titanium-silicon molecular sieve were measured by transmission electron microscopy-energy dispersive X-ray spectroscopy (TEM-EDX) (the photographs are shown in fig. 3). Firstly, dispersing a sample by using ethanol, ensuring that crystal grains are not overlapped and loaded on a copper net. The sample amount is reduced as much as possible during dispersion so that the particles are not superposed together, then the appearance of the sample is observed through a Transmission Electron Microscope (TEM), single isolated particles are randomly selected in a field of view and made into a straight line along the diameter direction of the particles, 6 measuring points with the sequence of 1, 2, 3, 4, 5 and 6 are uniformly selected from one end to the other end, the energy spectrum analysis microcosmic composition is sequentially carried out, and the SiO is respectively measured₂Content and TiO₂Content of TiO calculated from the above₂With SiO₂The molar ratio of (a) to (b). Target TiO of titanium silicalite molecular sieve edge₂With SiO₂Molar ratio (1 st measurement point andTiO at the 6 th measuring point₂With SiO₂Average value of molar ratio) is surface titanium-silicon ratio, and target point TiO of titanium-silicon molecular sieve center₂With SiO₂Molar ratio (TiO at measurement points 3 and 4₂With SiO₂The average value of the mole ratio) is the bulk titanium-silicon ratio.

The grain size (minor axis direction) of the titanium-silicon molecular sieve is measured by a TEM-EDX method, a TEM electron microscope experiment is carried out on a Tecnai F20G2S-TWIN type transmission electron microscope of FEI company, an energy filtering system GIF2001 of Gatan company is provided, and an X-ray energy spectrometer is provided as an accessory. The electron microscope sample is prepared on a micro-grid with the diameter of 3mm by adopting a suspension dispersion method.

XRD measuring method adopts Panalytical Empyrean X-ray diffractometer of Philips company to measure XRD phases, and the measuring conditions are as follows: cu target, Ka radiation, Ni filter, tube voltage of 40kV, tube current of 250mA, scintillation counter, step width of 0.02 degree, scanning range of 5-35 degrees, and scanning speed of 0.4 degree/min.

The BET specific surface area and pore volume were measured by a nitrogen adsorption capacity method according to the BJH calculation method (see petrochemical analysis method (RIPP test method), RIPP151-90, scientific Press, 1990).

The ultraviolet visible spectrum is tested on a UV550 ultraviolet spectrophotometer of JASCO company of Japan, and the test scanning wavelength range is 190-800 nm.

The raw materials used in the examples and comparative examples had the following properties:

the industrial semi coke is black powder with the granularity of 2.0-5.0 mm, and is produced by Kaiyuan coking Limited liability company in Shenmu county.

Tetrapropylammonium hydroxide, 20% strength by weight aqueous solution, available from Guangdong chemical plant.

Tetraethyl silicate, analytically pure, chemical reagents of the national pharmaceutical group, ltd.

Ammonia, analytically pure, 25% strength by weight aqueous solution.

Hydrogen peroxide, analytically pure, aqueous solution with concentration of 30 wt%.

The other reagents are not further explained, are all commercial products and are analytically pure.

Example 1

The titanium silicalite molecular sieve, labeled RTTS-1, is prepared as follows:

a. tetrapropylammonium hydroxide (TPAOH) aqueous solution with a concentration of 25 wt.%, Tetraethylorthosilicate (TEOS), tetrabutyltitanate (TBOT) and deionized water were mixed according to the ratio of TPAOH: TEOS: TBOT: h₂O ═ 0.2: 1: 0.015: the raw materials are weighed according to the molar ratio of 100 and are sequentially added into a beaker. Putting the mixture into a magnetic stirrer with heating and stirring functions, uniformly mixing, stirring for 3h at 80 ℃ for first hydrolysis, and supplementing evaporated water at any time to obtain colorless transparent hydrolysate, namely a first hydrolysis mixture.

b. Adding semi-coke-based activated carbon to the first hydrolysis mixture during stirring, wherein SiO is₂: semi-coke-based activated carbon 1: 0.16. transferring the mixed semi-coke-based activated carbon and the first hydrolysis mixture into a stainless steel closed reaction kettle, carrying out first hydrothermal treatment for 24 hours at 170 ℃, filtering the product, washing the product with deionized water for 10 times, wherein the water consumption is 10 times of the weight of the molecular sieve each time, placing the filter cake at 110 ℃ for drying for 24 hours, and then placing at 550 ℃ for roasting for 6 hours to obtain an intermediate titanium silicalite molecular sieve, which is marked as HS-1. The low-temperature nitrogen adsorption-desorption curve chart of the intermediate titanium silicalite molecular sieve is shown in figure 4.

c. 25 wt% aqueous tetrapropylammonium hydroxide (TPAOH), Tetraethylorthosilicate (TEOS), tetrabutyltitanate (TBOT) and deionized water were mixed as TPAOH: TEO: TBOT: h₂O is 2: 20: 1: weighing the raw materials according to the molar ratio of 550, sequentially adding the raw materials into a beaker, putting the beaker into a magnetic stirrer with heating and stirring functions, uniformly mixing the raw materials, stirring the mixture for 10 hours at 70 ℃ for second hydrolysis, and supplementing evaporated water at any time to obtain colorless transparent hydrolysate, namely a second hydrolysis mixture.

d. Mixing the intermediate titanium silicalite HS-1, the second hydrolysis mixture and ammonium chloride to obtain a mixed material, wherein TiO in the mixed material₂、SiO₂And NH₄ ⁺In a molar ratio of 1: 35: 0.3. transferring the mixed material to a stainless steel reaction kettle, carrying out second hydrothermal treatment at 170 ℃ for 24 hours, filtering, washing, and carrying out hydrothermal treatment at 120 DEG CDrying for 24 hours, and roasting for 6 hours at 550 ℃ to obtain the titanium silicalite molecular sieve prepared by the embodiment, which is marked as RTTS-1.

The preparation method of the semi-coke-based activated carbon comprises the following steps: mechanically grinding commercial industrial semi-coke to 120-mesh 200-mesh, weighing 15g of semi-coke powder, mixing KOH accounting for 10 wt% of the semi-coke, 5g of an activating assistant and 15g of water to prepare a steeping liquor, carrying out etching activation treatment on the semi-coke powder for 24h, then transferring the semi-coke powder into a stainless steel reaction tube, carrying out dredging activation treatment by raising the temperature to 850 ℃ in a flowing water vapor atmosphere, cooling, taking out the solid, washing and filtering the solid by using a 5 wt% hydrochloric acid solution, washing the solid to be neutral by using deionized water, and drying the solid at 106 ℃ for one day to obtain the semi-coke-based activated carbon.

The XRD spectrogram of the titanium silicalite RTTS-1 is shown in figure 1, the TEM electron micrograph of the RTTS-1 is shown in figure 2, and the TEM-EDX electron micrograph of the RTTS-1 is shown in figure 3. The difference of the adsorption amount is recorded as DeltaV, the mesopore volume/the total pore volume, the ratio of the surface titanium-silicon ratio to the bulk titanium-silicon ratio and other parameters are listed in Table 5.

Examples 2 to 15

Titanium silicalite molecular sieves, labeled RTTS-2 to RTTS-15, were prepared according to the procedure of example 1 and the raw material ratios and synthesis conditions in tables 1 to 4, respectively. The difference in adsorption was recorded as Δ V, mesopore volume/total pore volume, surface titanium-silicon ratio and bulk titanium-silicon ratio, and the like, and the parameters are shown in table 5.

Comparative example 1

This comparative example illustrates the preparation of a conventional TS-1 molecular sieve according to the prior art (Zeolite, 1992, Vol.12, pp. 943 to 950).

41.6g tetraethyl orthosilicate was mixed with 24.4g aqueous tetrapropylammonium hydroxide (25.05 wt%), 95.2g deionized water was added and mixed uniformly; then hydrolyzing for 1.0h at 60 ℃ to obtain a hydrolysis solution of tetraethyl silicate. Under the action of vigorous stirring, a solution consisting of 2.0g of tetrabutyl titanate and 10.0g of isopropanol is slowly dropped into the solution, and the mixture is stirred for 3 hours at 75 ℃ to obtain a clear and transparent colloid. And then the colloid is moved into a stainless steel closed reaction kettle, and is crystallized for 3 days at the constant temperature of 170 ℃, so that a conventional TS-1 molecular sieve sample, which is marked as CTS-1, can be obtained.

Comparative example 2

This comparative example illustrates the preparation of titanium silicalite molecular sieves according to the current method of hard templating agents (chem. Commun.,2000, 2157-2158.).

Adopting tetrapropylammonium hydroxide, ethanol and deionized water to carry out primary wet impregnation on BP700 carbon black particles (18nm), then after the ethanol is volatilized, mixing the carbon black particles with tetraethoxysilane, tetrapropylammonium hydroxide, tetraethyl titanate and deionized water under the stirring condition to obtain TPA (terephthalic acid) with the molar ratio₂O：TiO₂：SiO₂：H₂O20: 1: 100: 200, and aging for 3 hours; transferring the aging solution to a pressure-resistant stainless steel reaction kettle; heating to 170 ℃ under stirring and crystallizing for 72h under autogenous pressure. And after the stainless steel pressure-resistant reaction kettle is cooled to room temperature, recovering the obtained titanium silicalite molecular sieve which is not roasted, drying the titanium silicalite molecular sieve at 110 ℃ for 10 hours, and roasting the titanium silicalite molecular sieve at 550 ℃ for 8 hours to obtain the hierarchical pore titanium silicalite molecular sieve marked as CTS-2.

Comparative example 3

This comparative example illustrates the preparation of a titanium silicalite molecular sieve according to the method of example 1, except that the intermediate titanium silicalite molecular sieve used in step d is the titanium silicalite molecular sieve CTS-1 of comparative example 1, and the resulting hierarchical pore titanium silicalite molecular sieve is designated CTS-3.

TABLE 1

TABLE 2

TABLE 3

TABLE 4

TABLE 5

Test example

The samples RTTS-1 to RTTS-15 obtained in examples 1 to 15 and the molecular sieve samples CTS-1 to CTS-3 obtained by the method of comparative example were tested for their catalytic effects on the acetophenone ammoximation reaction.

The acetophenone oxamidination reaction was carried out in a 250mL three-necked flask reaction apparatus with an automatic temperature-controlled water bath, magnetic stirring and a condensate reflux system. Adding 1.96g of molecular sieve catalyst, 39g of solvent ethanol, 27.2g of ammonia water (mass fraction of 25%) and 19.6g of acetophenone into a three-neck flask in sequence, placing the three-neck flask into a water bath kettle with preset reaction temperature, slowly adding 27.2g of hydrogen peroxide (mass fraction of 30%) into a reaction system, and cooling to stop reaction after the reaction is finished. Adding a certain amount of ethanol into the reaction solution for homogeneous phase, filtering and separating liquid from solid, adding a certain amount of internal standard substance into the filtrate, measuring the product composition of the obtained product on an Agilent 6890N chromatograph by using an HP-5 capillary column, and calculating the result according to an internal standard method without integrating the solvent ethanol, wherein the result is shown in Table 6.

The conversion rate of acetophenone and selectivity of acetophenone oxime are calculated according to the following formulas:

conversion of acetophenone [ [ (M)₀-M_CHO)/M₀]×100％

Acetophenone oxime selectivity ═ M_CHOX/(M₀-M_CHO)]×100％

Wherein the initial amount of acetophenone is designated M₀The mass of unreacted acetophenone is designated M_CHOThe mass of the acetophenone oxime is marked as M_CHOX。

TABLE 6

Numbering	Conversion of acetophenone,% of	Acetophenone oxime selectivity,%
			Example 1	99.78	99.55
Example 2	91.33	92.33
			Example 3	85.43	90.76
Example 4	92.29	95.55
			Example 5	96.58	99.05
Example 6	98.88	97.89
			Example 7	99.55	98.47
Example 8	98.65	98.79
			Example 9	99.14	98.22
Example 10	99.22	98.78
			Example 11	98.85	97.25
Example 12	98.25	98.8
			Example 13	98.88	97.25
Example 14	95.69	96.21
			Example 15	92.89	93.33
Comparative example 1	62.31	87.23
			Comparative example 2	45.36	52.86
Comparative example 3	69.25	88.25

As can be seen from Table 6, the titanium silicalite molecular sieve disclosed by the invention has higher catalytic activity, and is beneficial to improving the conversion rate of raw materials and the selectivity of target products when being used in the process of producing ketoxime by the ammoximation reaction of macromolecular ketones.

The preferred embodiments of the present disclosure are described in detail with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

It should be noted that, in the foregoing embodiments, various features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various combinations that are possible in the present disclosure are not described again.

In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.

Claims

1. The titanium silicalite molecular sieve is characterized by consisting of oxygen element, silicon element and titanium element, wherein TiO of the titanium silicalite molecular sieve is calculated by oxide and calculated by molar weight₂With SiO₂In a molar ratio of 1: (25-100); the ratio of the surface titanium-silicon ratio of the titanium-silicon molecular sieve to the bulk phase titanium-silicon ratio is 1.7-3.9, wherein the titanium-silicon ratio refers to TiO₂With SiO₂The molar ratio of (A) to (B); when the titanium-silicon molecular sieve is subjected to BET nitrogen adsorption and desorption test, p/p₀The adsorption capacity and p/p of the titanium silicalite molecular sieve is 0.8₀When the adsorption capacity of the titanium silicalite molecular sieve is 0.2, the difference of the adsorption capacity is recorded as delta V, and the delta V is more than 26 mL/g.

2. The titanium silicalite molecular sieve of claim 1, wherein Δ V is 26-60mL/g, preferably 26-55 mL/g.

3. The titanium silicalite molecular sieve of claim 1, wherein the titanium silicalite molecular sieve has a BET total specific surface area of 400-600m²The ratio of the mesoporous volume to the total pore volume is 50-70%.

4. The titanium silicalite molecular sieve of any one of claims 1 to 3, wherein the titanium silicalite molecular sieve has an intragranular multiple hollow structure.

5. A method of preparing a titanium silicalite molecular sieve, the method comprising:

wherein the molar ratio of the first titanium source to the first silicon source is less than the molar ratio of the second titanium source to the first silicon sourceThe molar ratio of the second silicon source, the first silicon source and the second silicon source are SiO₂The first titanium source and the second titanium source are calculated as TiO₂And (6) counting.

6. The method of claim 5, wherein the carbon-containing porous material is carbon nanotubes, carbon nanofibers, cracked carbon black, or semi-coke based activated carbon, or a combination of two or three thereof; preferably, the carbon-containing porous material is carbon nano tube and/or semi-coke-based activated carbon.

7. The method of claim 5, wherein the first and second structure directing agents are each independently a quaternary ammonium base compound; the quaternary ammonium base compound is tetraethylammonium hydroxide, tetrapropylammonium hydroxide or tetrabutylammonium hydroxide.

8. The method of claim 5, wherein the first structure directing agent and the second structure directing agent are each independently a mixture of a quaternary ammonium salt compound and one or more of a quaternary ammonium base compound, a fatty amine compound, an alcohol amine compound, and an aromatic amine compound;

9. The method of claim 8, wherein the fatty amine compound is ethylamine, n-butylamine, butanediamine, or hexanediamine, or a combination of two or three thereof;

10. The method of claim 5, wherein in step a, the molar ratio of the amounts of the first structure directing agent, the first silicon source, the first titanium source and water is (0.05-1.5): 1: (0.001-0.05): (10-400), preferably (0.1-0.8): 1: (0.005-0.02): (30-200), wherein the first silicon source is SiO₂The first titanium source is calculated as TiO₂And (6) counting.

11. The method of claim 5, wherein the first and second silicon sources are each an organosilicate, preferably each independently is tetramethyl orthosilicate, tetraethyl orthosilicate, tetrapropyl orthosilicate, tetrabutyl orthosilicate, or dimethoxydiethoxysilane, or a combination of two or three thereof;

12. The method as claimed in claim 5, wherein the carbon-containing porous material is used in the amount of 0.001-0.5 molar parts in step b with respect to 1 molar part of the first silicon source, which is SiO₂The carbon-containing porous material is calculated by carbon element;

13. The process of claim 5, wherein in step a, the temperature of the first hydrolysis is 65-95 ℃ for 1-15 hours; and/or the like and/or,

14. The method of claim 5, wherein in step c, the second structure directing agent, the second silicon source, the second titanium source and water are used in a molar ratio of (1.5-5): (10-80): 1: (400-1000), the second silicon source is SiO₂The second titanium source is calculated as TiO₂And (6) counting.

15. The process according to claim 5, wherein in step c, the temperature of the second hydrolysis is 50-95 ℃ for 1-12 hours.

16. The method of claim 5, wherein in step d, the inorganic ammonium source is ammonium chloride, ammonium sulfate, ammonium oxalate, ammonium carbonate, or aqueous ammonia, or a combination of two or three thereof.

17. The method of claim 5, wherein in step d, TiO is in the mixed material₂、SiO₂And NH₄ ⁺In a molar ratio of 1: (10-200): (0-4), preferably, TiO₂、SiO₂And NH₄ ⁺In a molar ratio of 1: (20-100): (0.1-0.8).

18. The method as claimed in claim 5, wherein the temperature of the second hydrothermal treatment in step d is 190 ℃ for 5-96 hours.

19. The method as claimed in claim 5, wherein the drying temperature in step d is 100-200 ℃ for 1-24 hours; the roasting temperature is 350-650 ℃ and the roasting time is 1-6 hours.

20. A titanium silicalite molecular sieve produced by the process of any one of claims 5 to 19.

21. A catalyst comprising the titanium silicalite molecular sieve of any one of claims 1 to 4 and claim 20.

22. A process for producing a ketoxime by ammoximation of a macromolecular ketone, which comprises using the catalyst according to claim 21.

23. The method of claim 22, wherein the macromolecular ketone is cyclohexanone, cyclopentanone, cyclododecanone, or acetophenone.