Titanium-silicon molecular sieve, preparation method thereof and method for producing ketoxime by macromolecular ketone ammoximation reaction
阅读说明：本技术 钛硅分子筛及其制备方法和大分子酮类氨肟化反应生产酮肟的方法 (Titanium-silicon molecular sieve, preparation method thereof and method for producing ketoxime by macromolecular ketone ammoximation reaction ) 是由 林民 杨永佳 朱斌 夏长久 袁蕙 卢立军 郑爱国 罗一斌 舒兴田 于 2019-10-31 设计创作，主要内容包括：本公开涉及一种钛硅分子筛及其制备方法和大分子酮类氨肟化反应生产酮肟的方法,钛硅分子筛由氧元素、硅元素和钛元素组成,以氧化物计并以摩尔量计,钛硅分子筛的TiO-2与SiO-2的摩尔比为1：(20-100)；钛硅分子筛的表面钛硅比与体相钛硅比的比值为1.5-3.6,钛硅比是指TiO-2与SiO-2的摩尔比；对钛硅分子筛进行紫外可见光谱测试时,位移为210nm的谱峰面积与位移为210nm、270nm和330nm的谱峰面积之和的比记为a/b,a/b为55％以上。本公开的钛硅分子筛表面富钛且骨架钛含量高,催化活性高,将其用于大分子酮类氨肟化反应生产酮肟工艺中有利于提高原料转化率和目标产物选择性。(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 weight 2 With SiO 2 In a molar ratio of 1: (20-100); the ratio of the surface titanium-silicon ratio of the titanium-silicon molecular sieve to the bulk phase titanium-silicon ratio is 1.5-3.6, wherein the titanium-silicon ratio refers to TiO 2 With SiO 2 The molar ratio of (A) to (B); when the titanium silicalite molecular sieve is subjected to an ultraviolet-visible spectrum test, the ratio of the peak area with the displacement of 210nm to the sum of the peak areas with the displacements of 210nm, 270nm and 330nm is recorded as a/b, and the a/b is more than 55 percent. Titanium of the present disclosureThe silicon molecular sieve is rich in titanium on the surface, high in framework titanium content and high in catalytic activity, and is favorable for improving the conversion rate of raw materials and the selectivity of a target product when being used in the process of producing ketoxime by the ammoximation reaction of macromolecular ketones.)
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: (20-100); the ratio of the surface titanium-silicon ratio of the titanium-silicon molecular sieve to the bulk phase titanium-silicon ratio is 1.5-3.6, wherein the titanium-silicon ratio refers to TiO2With SiO2The molar ratio of (A) to (B); when the titanium silicalite molecular sieve is subjected to ultraviolet visible spectrum test, the ratio of the area of the spectrum peak with the displacement of 210nm to the sum of the areas of the spectrum peaks with the displacements of 210nm, 270nm and 330nm is recorded as a/b, and the a/b is more than 55 percent.
2. The titanium silicalite molecular sieve of claim 1, wherein a/b is 55-85%.
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 volume ratio of the mesoporous volume to the total pore volume is 45-60%.
4. The titanium silicalite molecular sieve of claim 1, wherein the titanium silicalite molecular sieve has a p/p ratio when subjected to a BET nitrogen adsorption and desorption test0The adsorption capacity and p/p of the titanium silicalite molecular sieve is 0.80And when 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 24-52 mL/g.
5. The titanium silicalite molecular sieve of any one of claims 1 to 4, wherein the titanium silicalite molecular sieve has an intragranular multiple hollow structure.
6. A method of preparing a titanium silicalite molecular sieve, the method comprising:
a. mixing a first structure directing agent, a first silicon source, a first titanium source and water, and then carrying out first hydrolysis for 0.5-27 hours at 35-99 ℃ to obtain a first hydrolysis mixture;
b. subjecting the first hydrolysis mixture to a first hydrothermal treatment at 90-190 ℃ for 1-600 hours, and collecting a first solid product;
c. mixing inorganic base, the first solid product and water, performing second hydrothermal treatment for 1-240 hours at 50-200 ℃ in a pressure-resistant closed container, and collecting a second solid product;
d. 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;
e. mixing the second solid product, the second hydrolysis mixture and an optional inorganic ammonium source to obtain a mixed material, performing a third hydrothermal treatment on the mixed material in a pressure-resistant closed container at 90-200 ℃ for 1-120 hours, and collecting a third solid product;
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.
7. The process of claim 6, wherein the inorganic base is an alkali metal hydroxide, a weak alkali metal acid salt, aqueous ammonia, or a basic ammonium salt, or a combination of two or three thereof;
preferably, the inorganic base is aqueous ammonia.
8. The method of claim 6, 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.
9. The method of claim 6, 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;
the quaternary ammonium base compound is tetrapropylammonium hydroxide, and the quaternary ammonium salt compound is tetrapropylammonium chloride and/or tetrapropylammonium bromide; alternatively, the first and second electrodes may be,
the quaternary ammonium base compound is tetrabutylammonium hydroxide, and the quaternary ammonium salt compound is tetrabutylammonium chloride and/or tetrabutylammonium bromide; alternatively, the first and second electrodes may be,
the quaternary ammonium base compound is tetraethylammonium hydroxide, and the quaternary ammonium salt compound is tetraethylammonium chloride and/or tetraethylammonium bromide.
10. The method of claim 9, wherein the fatty amine compound is ethylamine, n-butylamine, butanediamine, or hexanediamine, 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.
11. The method of claim 6, 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 (0.01-1): 1: (0.001-0.1): (10-400), preferably (0.06-0.5): 1: (0.005-0.02): (10-100), wherein the first silicon source is SiO2The first titanium source is calculated as TiO2And (6) counting.
12. The process of claim 6, wherein in step a, the temperature of the first hydrolysis is 50-90 ℃ for 1-12 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.
13. The method of claim 6, 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;
the first titanium source and the second titanium source are each independently an inorganic titanium salt and/or an organic titanate.
14. The process of claim 6, wherein in step c, the molar ratio of the amounts of the inorganic base, the first solid product, and water is (0.001-0.5): 1: (5-30), wherein the inorganic base is OH-The first solid product is calculated by SiO2Counting;
preferably, the molar ratio of the amounts of the inorganic base, the first solid product and water is (0.01-0.1): 1: (10-20).
15. The process according to claim 6, wherein in step c, the temperature of the second hydrothermal treatment is 70-190 ℃ for 5-168 hours.
16. The method of claim 6, wherein in step d, 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): (10-100): 1: (400-1000), the second silicon source is SiO2The second titanium source is calculated as TiO2And (6) counting.
17. The process according to claim 6, wherein in step d, the temperature of the second hydrolysis is 50-95 ℃ for 1-12 hours.
18. The method of claim 6, wherein in step e, the inorganic ammonium source is ammonium chloride, ammonium sulfate, ammonium oxalate, ammonium carbonate, or aqueous ammonia, or a combination of two or three thereof.
19. The method as claimed in claim 6, wherein the temperature of the third hydrothermal treatment in step e is 190 ℃ for 5-96 hours.
20. The method of claim 6, wherein the TiO in the mixed material2、SiO2: and 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).
21. The method of claim 6, wherein step e further comprises: collecting the third solid product, and then drying and roasting; 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 1-8 hours.
22. A titanium silicalite molecular sieve produced by the process of any one of claims 6 to 21.
23. A catalyst comprising the titanium silicalite molecular sieve of any one of claims 1 to 5 and claim 22.
24. A process for producing a ketoxime by ammoximation of a macromolecular ketone, which comprises using the catalyst according to claim 23.
25. The method of claim 24, wherein the macromolecular ketone is cyclohexanone, cyclopentanone, cyclododecanone, or acetophenone.
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 H2O2Oxidation of the structureThe 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 the molecular sieve skeleton, a strategy of hydrolyzing organic silicone grease firstly and then slowly dripping organic titanate ester 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 skeleton titanium, a certain amount of non-skeleton 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 high in framework titanium content, and can improve the conversion rate of raw materials and the selectivity of target products when being used in the process of producing ketoxime through the ammoximation reaction of macromolecular ketones.
In order to achieve the above object, the first aspect of 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 TiO of the titanium silicalite molecular sieve is calculated by oxides and calculated by mol2With SiO2In a molar ratio of 1: (20-100); the ratio of the surface titanium-silicon ratio of the titanium-silicon molecular sieve to the bulk phase titanium-silicon ratio is 1.5-3.6, wherein the titanium-silicon ratio refers to TiO2With SiO2The molar ratio of (A) to (B); when the titanium silicalite molecular sieve is subjected to ultraviolet visible spectrum test, the ratio of the area of the spectrum peak with the displacement of 210nm to the sum of the areas of the spectrum peaks with the displacements of 210nm, 270nm and 330nm is recorded as a/b, and the a/b is more than 55 percent.
Alternatively, a/b is 55-85%.
Optionally, the titanium silicalite molecular sieve has a BET total specific surface area of 400-2The volume ratio of the mesoporous volume to the total pore volume is 45-60%.
Optionally, when the titanium silicalite molecular sieve is subjected to a BET nitrogen adsorption and desorption test, p/p0The adsorption capacity and p/p of the titanium silicalite molecular sieve is 0.80And when 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 24-52 mL/g.
Optionally, the titanium silicalite molecular sieve has an intragranular multiple hollow structure.
A second aspect of the present disclosure provides a method of preparing a titanium silicalite molecular sieve, the method comprising:
a. mixing a first structure directing agent, a first silicon source, a first titanium source and water, and then carrying out first hydrolysis for 0.5-27 hours at 35-99 ℃ to obtain a first hydrolysis mixture;
b. subjecting the first hydrolysis mixture to a first hydrothermal treatment at 90-190 ℃ for 1-600 hours, and collecting a first solid product;
c. mixing inorganic base, the first solid product and water, performing second hydrothermal treatment for 1-240 hours at 50-200 ℃ in a pressure-resistant closed container, and collecting a second solid product;
d. 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;
e. mixing the second solid product, the second hydrolysis mixture and an optional inorganic ammonium source to obtain a mixed material, performing a third hydrothermal treatment on the mixed material in a pressure-resistant closed container at 90-200 ℃ for 1-120 hours, and collecting a third solid product;
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 inorganic base is alkali metal hydroxide, weak alkali metal salt, ammonia water or alkali ammonium salt, or a combination of two or three of them;
preferably, the inorganic base is aqueous ammonia.
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; alternatively, the first and second electrodes may be,
the quaternary ammonium base compound is tetrabutylammonium hydroxide, and the quaternary ammonium salt compound is tetrabutylammonium chloride and/or tetrabutylammonium bromide; alternatively, the first and second electrodes may be,
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 first structure directing agent, the first silicon source, the first titanium source and the water is (0.01-1): 1: (0.001-0.1): (10-400), preferably (0.06-0.5): 1: (0.005-0.02): (10-100), wherein the first silicon source is SiO2The first titanium source is calculated as TiO2And (6) counting.
Optionally, in step a, the temperature of the first hydrolysis is 50-90 ℃ and the time is 1-12 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, 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.
Alternatively, in step c, the inorganic base, the first solid product, and water are used in a molar ratio of (0.001-0.5): 1: (5-30), wherein the inorganic base is OH-The first solid product is calculated by SiO2Counting;
preferably, the molar ratio of the amounts of the inorganic base, the first solid product and water is (0.01-0.1): 1: (10-20).
Optionally, in step c, the temperature of the second hydrothermal treatment is 70-190 ℃ and the time is 5-168 hours.
Optionally, in step d, the molar ratio of the second structure directing agent, the second silicon source, the second titanium source and the water is (1.5-5): (10-100): 1: (400-1000), the second silicon source is SiO2The second titanium source is calculated as TiO2And (6) counting.
Optionally, in step d, the temperature of the second hydrolysis is 50-95 ℃ and the time is 1-12 hours.
Optionally, in step e, 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 the step e, the temperature of the third hydrothermal treatment is 130-.
Optionally, TiO in the mixed material2、SiO2: and 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, step e further comprises: collecting the third solid product, and then drying and roasting; 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 1-8 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 higher content of framework Ti, more framework Ti active centers are positioned on the surface layer, the utilization rate of the titanium active centers is high, the catalytic activity is high, and the titanium-silicon molecular sieve is used for the process for producing ketoxime by macromolecular ketone ammoximation reaction, and is favorable for improving the conversion rate of raw materials and the selectivity of target products.
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 a TEM electron micrograph of a titanium silicalite molecular sieve prepared in example 1 of the present disclosure;
FIG. 2 is a TEM-EDX electron micrograph of a titanium silicalite molecular sieve prepared in example 1 of the present disclosure;
figure 3 is a UV-Vis spectrum of a bulk 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: (20-100); the ratio of the surface titanium-silicon ratio of the titanium-silicon molecular sieve to the bulk phase titanium-silicon ratio is 1.5-3.6, wherein the titanium-silicon ratio refers to TiO2With SiO2The molar ratio of (A) to (B); when the titanium silicalite molecular sieve is subjected to an ultraviolet-visible spectrum test, the ratio of the peak area with the displacement of 210nm to the sum of the peak areas with the displacements of 210nm, 270nm and 330nm is recorded as a/b, and the a/b is more than 55 percent.
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-silicon molecular sieve disclosed by the invention is rich in titanium on the surface and has high framework titanium content, more framework titanium active centers are positioned on the surface layer, the utilization rate of the titanium active centers is high, and the activity of the catalyst is high.
In the present disclosure, uv-vis spectroscopy tests are well known to those skilled in the art, and may be performed, for example, on a uv spectrophotometer, where the scanning wavelength range may be 190-800 nm. 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 TiO in the whole molecular sieve crystal grains2With SiO2In 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, a/b is from 55 to 85%, more preferably from 55 to 70%.
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 is 45-60%. Preferably, the BET total specific surface area of the titanium silicalite molecular sieve can be 440-560m2The volume ratio of the mesoporous volume to the total pore volume can be 47-55%. The BET total specific surface area and pore volume may be measured according to conventional methods, and the present disclosure is not particularly limited thereto and is well known to those skilled in the art, for example, by the BET nitrogen adsorption and desorption test. 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, when a titanium silicalite molecular sieve is subjected to a 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 sieves at 0.2 is noted as DeltaV, and the DeltaV can be 24-52mL/g, and preferably, the DeltaV is 25-50 mL/g. Wherein, p/p0It is the ratio of the nitrogen partial pressure to the saturated vapor pressure of liquid nitrogen at the adsorption temperature in the BET nitrogen adsorption and desorption test. The BET nitrogen adsorption and desorption test may be performed according to a conventional method, and the present disclosure does not specifically limit this.
According to the disclosure, the titanium-silicon molecular sieve can have an in-crystal multi-hollow structure, and the in-crystal multi-hollow structure can effectively improve the diffusion performance of the molecular sieve and improve the catalytic activity of the molecular sieve.
A second aspect of the present disclosure provides a method of preparing a titanium silicalite molecular sieve, the method comprising:
a. mixing a first structure directing agent, a first silicon source, a first titanium source and water, and then carrying out first hydrolysis for 0.5-27 hours at 35-99 ℃ to obtain a first hydrolysis mixture;
b. subjecting the first hydrolysis mixture to a first hydrothermal treatment at 90-190 ℃ for 1-600 hours, and collecting a first solid product;
c. mixing inorganic base, the first solid product and water, performing second hydrothermal treatment for 1-240 hours at 50-200 ℃ in a pressure-resistant closed container, and collecting a second solid product;
d. 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;
e. mixing the second solid product, the second hydrolysis mixture and an optional inorganic ammonium source to obtain a mixed material, carrying out third hydrothermal treatment on the mixed material in a pressure-resistant closed container at 90-200 ℃ for 1-120 hours, and collecting a third solid product;
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 prepared by the method is rich in titanium on the surface and high in framework titanium content, more framework titanium active centers are positioned on the surface layer, the utilization rate of the titanium active centers is high, and the activity of the catalyst is high.
According to the present disclosure, the inorganic base may be an alkali metal hydroxide, an alkali metal weak acid salt, aqueous ammonia, or an alkali ammonium salt, or may be a combination of two or three thereof. For example, the alkali metal hydroxide is NaOH or KOH, the weak alkali metal salt is sodium carbonate, sodium acetate, and the alkaline ammonium salt is ammonium carbonate. Preferably, the inorganic base is aqueous ammonia.
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.
In one embodiment, the first structure directing agent and the second structure directing agent may each be tetrapropylammonium hydroxide, or may each independently be a mixture of tetrapropylammonium chloride and/or tetrapropylammonium bromide and 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 silicalite molecular sieve is 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 quaternary ammonium base compounds, fatty amine compounds, alcohol amine compounds and aromatic amine compounds, the molar ratio of tetrabutylammonium chloride and/or tetrabutylammonium bromide to one or more of the quaternary ammonium base compounds, fatty amine compounds, alcohol amine compounds and aromatic amine compounds may be 1: (0.2-7).
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 the group consisting of 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 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)nWhereinR5Is 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 R is6Is C1-C4 alkyl, and m is 1, 2 or 3. Preferably, the alkanolamine compound may be monoethanolamine, diethanolamine or triethanolamine, or may be 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 may be 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 (0.01-1): 1: (0.001-0.1): (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 (0.06-0.5): 1: (0.005-0.02): (10-100).
According to the present disclosure, the temperature of the first hydrolysis in step a is preferably 50 to 90 ℃ and the time is preferably 1 to 12 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, 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.
The first and second sources of silicon may be those commonly used to synthesize titanium silicalite molecular sieves well known to those skilled in the art in light of the present disclosure. In one embodiment, the first silicon source and the second silicon source may be respectively organic silicone grease, preferably, the first silicon source and the second silicon source may be respectively and independently tetramethyl orthosilicate, tetraethyl orthosilicate, tetrapropyl orthosilicate, tetrabutyl orthosilicate or dimethoxydiethoxysilane, or may be a combination of two or three of them.
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, and the organic titanate may be ethyl titanate, tetrapropyl titanate or tetrabutyl titanate.
According to the present disclosure, in step c, the inorganic base, the first solid product and water may be used in a molar ratio of (0.001-0.5): 1: (5-30) wherein the inorganic base is OH-The first solid product is calculated as SiO2Counting; preferably, the molar ratio of the amounts of the inorganic base, the first solid product and water may be (0.01-0.1): 1: (10-20). Within the range, the titanium silicalite molecular sieve with higher framework titanium content can be prepared.
According to the present disclosure, the temperature of the second hydrothermal treatment in step c is preferably 70 to 190 ℃ and the time is preferably 5 to 168 hours. The pressure of the second hydrothermal treatment is not particularly limited, and may be the autogenous pressure of the reaction system.
According to the present disclosure, in step d, 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): (10-100): 1: (400-1000), the second silicon source is SiO2The second titanium source is calculated as TiO2And (6) counting.
According to the present disclosure, the temperature of the second hydrolysis in step d 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 e, the inorganic ammonium source may be ammonium chloride, ammonium sulfate, ammonium oxalate, ammonium carbonate or aqueous ammonia, or may be a combination of two or three of them.
According to the present disclosure, in step e, the temperature of the third hydrothermal treatment is preferably 130-190 ℃ and the time is preferably 5-96 hours. The pressure of the third hydrothermal treatment is not particularly limited, and may be the autogenous pressure of the reaction system.
Further, step e may further include: and collecting the third solid product, drying and roasting. The temperature for drying and roasting can vary within a wide range, and in one embodiment, the temperature for drying can be 100-200 ℃ for 1-24 hours; the temperature for calcination can be 350-650 deg.C, and the time can be 1-8 hours. Preferably, the third 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.
In accordance with the present disclosure, in the mixture, TiO2、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 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 aspect of the present disclosure or as provided in the 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.
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. 2). 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 (TiO at 1 st measuring point and 6 th measuring point)2With 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.
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, the test scanning wavelength range is 190-800nm, and the test chart is shown in figure 3.
The raw materials used in the examples and comparative examples had the following properties:
ammonia, analytically pure, 25% strength by weight aqueous solution.
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 40 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. And (3) carrying out first hydrothermal treatment on the first hydrolysis mixture at 170 ℃ for 24 hours, 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, placing the filter cake at 110 ℃ for drying for 24 hours, and then placing at 550 ℃ for roasting for 6 hours to obtain the intermediate titanium silicalite molecular sieve A.
c. Ammonia water, the intermediate titanium silicalite molecular sieve A and water are mixed according to OH-、SiO2And H2The O molar ratio is 0.05: 1: 15, and performing second hydrothermal treatment at 120 ℃ for 25 hours, washing, flushing and recovering a product to obtain an intermediate titanium silicalite molecular sieve B, which is marked as HS-1.
d. 25% by weight of tetrapropylammonium hydroxide (TPAOH)Aqueous solution, tetraethyl orthosilicate (TEOS), tetrabutyl titanate (TBOT) and deionized water according to TPAOH: TEOS: 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.
e. Mixing the intermediate titanium silicalite molecular sieve B, the second hydrolysis mixture and ammonium chloride to obtain a mixture, wherein TiO in the mixture2、SiO2And NH4 +In a molar ratio of 1: 35: 0.3. and (3) transferring the mixed material into a stainless steel reaction kettle, carrying out second hydrothermal treatment at 170 ℃ for 24 hours, filtering, washing, drying at 120 ℃ for 24 hours, and roasting at 550 ℃ for 6 hours to obtain the titanium silicalite molecular sieve, which is recorded as RTTS-1 and prepared in the embodiment.
The TEM electron micrograph of the titanium silicalite RTTS-1 is shown in figure 1, the TEM-EDX electron micrograph of the RTTS-1 is shown in figure 2, and the UV-Vis spectrogram of the RTTS-1 is shown in figure 3. The parameters of the molecular sieve, such as mesopore volume/total pore volume, surface titanium-silicon ratio and bulk titanium-silicon ratio, are listed in table 6.
Examples 2 to 17
Titanium silicalite molecular sieves, labeled RTTS-2 to RTTS-17, were prepared according to the procedure of example 1 and the raw material ratios and synthesis conditions in tables 1 to 5. The parameters of mesopore volume/total pore volume, surface titanium to silicon ratio and bulk titanium to silicon ratio are listed in Table 6.
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 a titanium silicalite molecular sieve according to the existing method of treatment with a silylating agent (chem. Commun., 2009,11: 1407-.
Under the condition of stirring, mixing ethyl orthosilicate, tetrapropylammonium hydroxide, tetrabutyl titanate and deionized water to obtain SiO in molar ratio2: structure directing agent: TiO 22：H2O is 1: 0.2: 0.025: 50 of a homogeneous mixture; pre-crystallizing at 90 deg.C for 24 hr, and mixing with SiO2: silylation reagent ═ 1: 0.12, adding N-phenyl-triaminopropyltrimethoxysilane into the titanium silicalite molecular sieve precursor gel obtained by pre-crystallization, uniformly stirring, and transferring the obtained titanium silicalite molecular sieve precursor into a pressure-resistant stainless steel reaction kettle; heating to 170 ℃ under stirring and crystallizing for 8h 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 6 hours, and roasting the titanium silicalite molecular sieve at 550 ℃ for 4 hours to obtain the hierarchical pore titanium silicalite molecular sieve which is prepared by silanization and 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 c 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
TABLE 6
Test example
This test example demonstrates the catalytic effect of the molecular sieve samples RTTS-1 to RTTS-17 obtained in examples 1 to 17 according to the invention and CTS-1 to CTS-3 obtained by the method of comparative example on the cyclohexanone ammoximation reaction.
The cyclohexanone ammoximation reaction is carried out in a 250mL three-mouth bottle reaction device with an automatic temperature control water bath, magnetic stirring and a condensation 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 cyclohexanone 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 the reaction system, and cooling to stop the 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 7.
The conversion rate of cyclohexanone and the selectivity of cyclohexanone oxime are respectively calculated according to the following formulas:
cyclohexanone conversion ═ M0-MCHO)/M0]×100％
Cyclohexanone oxime selectivity ═ MCHOX/(M0-MCHO)]×100％
Wherein the mass of the initial cyclohexanone is denoted as M0The mass of unreacted cyclohexanone is denoted MCHOThe mass of cyclohexanone oxime is denoted as MCHOX。
TABLE 7
Numbering
Cyclohexanone conversion rate,% of
Cyclohexanone oxime selectivity,%
Example 1
98.25
98.13
Example 2
92.66
93.01
Example 3
90.03
92.22
Example 4
85.55
92.10
Example 5
91.12
90.22
Example 6
90.22
91.39
Example 7
99.22
98.98
Example 8
96.98
96.12
Example 9
98.77
98.58
Example 10
99.75
98.79
Example 11
99.25
98.28
Example 12
97.95
97.43
Example 13
99.15
97.28
Example 14
99.89
99.48
Example 15
99.88
98.25
Example 16
96.13
95.24
Example 17
93.21
94.38
Comparative example 1
72.73
85.25
Comparative example 2
45.36
52.86
Comparative example 3
80.73
91.25
From table 7, it can be seen that the titanium silicalite molecular sieve disclosed by the present disclosure has high catalytic activity, and is beneficial to improving the raw material conversion rate and the target product selectivity 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.
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