CN110759353A

CN110759353A - Tin-titanium-silicon molecular sieve, preparation method and application thereof, and phenol oxidation method

Info

Publication number: CN110759353A
Application number: CN201810844454.5A
Authority: CN
Inventors: 史春风; 林民; 朱斌
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petrochemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petrochemical Corp
Priority date: 2018-07-27
Filing date: 2018-07-27
Publication date: 2020-02-07
Anticipated expiration: 2038-07-27
Also published as: CN110759353B

Abstract

The present disclosure relates to a tin-titanium-silicon molecular sieve, a preparation method and an application thereof, and a phenol oxidation method, wherein the molecular sieve comprises: tin element, titanium element, silicon element and oxygen element, wherein the molecular sieve satisfies X_1.1‑2/X_0.5‑1＝A，0.02<A<0.3, preferably 0.05<A<0.25，X_0.5‑1The ratio of the pore diameter of the micropores of the molecular sieve in the range of 0.5-1nm to the distribution quantity of the total pore diameter, X_1.1‑2Is the proportion of the pore diameter of the micropores of the molecular sieve in the range of 1.1-2nm in the distribution quantity of the pore diameter of the total micropores. The tin-titanium-silicon molecular sieve has a special physicochemical characteristic structure, is used for phenol oxidation reaction, is favorable for improving the conversion rate of phenol and is favorable for modulationSelectivity of the target product.

Description

Tin-titanium-silicon molecular sieve, preparation method and application thereof, and phenol oxidation method

Technical Field

The disclosure relates to a tin-titanium-silicon molecular sieve, a preparation method and application thereof, and a phenol oxidation method.

Background

The titanium-silicon molecular sieve is a molecular sieve with a framework composed of silicon, titanium and oxygen elements, and has wide application prospect in petroleum refining and petrochemical industry. Wherein, the TS-1 molecular sieve is a novel titanium silicalite molecular sieve with excellent catalytic selective oxidation performance formed by introducing a transition metal element titanium into a molecular sieve framework with a ZSM-5 structure.

TS-1 not only has the catalytic oxidation effect of titanium, but also has the shape-selective effect and excellent stability of a ZSM-5 molecular sieve, and successfully realizes industrial application in the process of preparing cyclohexanone oxime by performing catalytic ammoxidation on cyclohexanone. However, generally, the catalytic performance of the catalyst deteriorates after a certain period of operation, and the catalyst undergoes deactivation. Inactivation is further classified into temporary inactivation and permanent inactivation. A temporarily deactivated catalyst may be regenerated to restore some or all of its activity, while a permanently deactivated catalyst may not be regenerated to restore activity (activity after regeneration is less than 50% of the original activity). The titanium-silicon molecular sieve can not be recycled at present after the inactivation of the titanium-silicon molecular sieve in an alkaline environment, particularly the permanent inactivation of the ammoximation catalyst TS-1, and is mainly treated by adopting a stacking and burying mode. Thus, precious land resources and storage space are occupied, and the development of a technology for recycling the deactivated ammoximation catalyst is urgently needed.

Disclosure of Invention

The purpose of the present disclosure is to provide a tin-titanium-silicon molecular sieve, a preparation method and an application thereof, and a phenol oxidation method. The tin-titanium-silicon molecular sieve is used for catalyzing phenol oxidation reaction, and can effectively improve the selectivity of high-value target products.

To achieve the above object, a first aspect of the present disclosure: providing a tin-titanium-silicon molecular sieve, the molecular sieve comprising: tin element, titanium element, silicon element and oxygen element, wherein the molecular sieve satisfies X_1.1-2/X_0.5-1＝A，0.02<A<0.3, preferably 0.05<A<0.25，X_0.5-1The pore diameter of the micropores of the molecular sieve in the range of 0.5-1nm accounts for the total diameterProportion of pore size distribution, X_1.1-2Is the proportion of the pore diameter of the micropores of the molecular sieve in the range of 1.1-2nm in the distribution quantity of the pore diameter of the total micropores.

Alternatively, the molecular sieve satisfies I₉₆₀/I₈₀₀＝B，0.2<B<1，I₉₆₀The infrared absorption spectrum of the molecular sieve is 960cm^-1Absorption intensity in the vicinity, I₈₀₀The infrared absorption spectrum of the molecular sieve is 800cm^-1Absorption intensity in the vicinity, preferably, 0.3<B<0.8。

Optionally, the molecular sieve satisfies T_w/T_k＝C，0.6<C<0.95，T_wIs the micropore volume of the molecular sieve, T_kIs the total pore volume of the molecular sieve, preferably, 0.65<C<0.9。

Optionally, the molecular sieve has a molar ratio of silicon, titanium and tin of 100: (0.1-10): (0.01-5), preferably 100: (0.2-5): (0.2-2.5).

Optionally, the surface silicon-titanium ratio of the molecular sieve is not lower than the bulk silicon-titanium ratio, wherein the silicon-titanium ratio refers to the molar ratio of silicon oxide to titanium oxide;

preferably, the ratio of the surface silicon-titanium ratio to the bulk silicon-titanium ratio is 1.2-5;

further preferably, the ratio of the surface silicon-titanium ratio to the bulk silicon-titanium ratio is 1.5-3.5.

Alternatively, the molecular sieve is a molecular sieve of MFI structure, a molecular sieve of BEA structure, a molecular sieve of MEL structure, or a molecular sieve of MOR structure.

In a second aspect of the present disclosure: there is provided a method of preparing a tin titanium silicalite molecular sieve according to the first aspect of the disclosure, the method comprising:

(1) mixing a catalyst containing a titanium-silicon molecular sieve with a first heat treatment solution, carrying out first heat treatment for 0.5-360h at 40-200 ℃, and then carrying out solid-liquid separation on the obtained mixture to obtain a first solid, wherein the first heat treatment solution is an acidic solution containing a first silicon source;

(2) mixing the first solid with a second heat treatment liquid, and carrying out second heat treatment for 0.5-96h at the temperature of 100-200 ℃, wherein the second heat treatment liquid contains a second silicon source, a tin source, an alkali source and water;

wherein, SiO is used₂And (2) calculating the molar ratio of the catalyst containing the titanium silicalite molecular sieve to the first silicon source in the step (1) to be 100: (0.1-10), and the molar ratio of the catalyst containing the titanium silicalite molecular sieves in the step (1) to the second silicon source in the step (2) is 100: (5-50).

Optionally, the catalyst containing the titanium silicalite molecular sieve in the step (1) is a discharging agent of a reaction device using the titanium silicalite molecular sieve as the catalyst, preferably a discharging agent of an ammoximation reaction device;

preferably, the titanium silicalite molecular sieve is of an MFI structure, and the activity of the discharging agent is less than 50% of the activity of the titanium silicalite molecular sieve in a fresh state;

preferably, the discharging agent is calcined before being mixed with the first heat treatment liquid.

Optionally, the second heat treatment sequentially goes through a stage (1), a stage (2) and a stage (3), wherein the stage (1) is maintained at 140 ℃ for 2-24 hours at 100-; preferably, the temperature difference between stage (3) and stage (2) is at least 20 ℃, preferably 25-60 ℃; preferably, the temperature rising rate from room temperature to the stage (1) is 0.1-20 ℃/min, the temperature rising rate from the stage (1) to the stage (2) is 1-50 ℃/min, and the temperature falling rate from the stage (2) to the stage (3) is 1-20 ℃/min.

Alternatively, the catalyst containing titanium silicalite molecular sieves: a tin source: acid: alkali source: the molar ratio of water is 100: (0.1-10): (0.005-50): (0.5-50): (20-1000), wherein the catalyst containing the titanium silicalite molecular sieve is SiO₂In terms of H, the acid is⁺The alkali source is counted as N when containing nitrogen element, and the alkali source is counted as OH when not containing nitrogen element^-Counting;

preferably, the acid is an organic acid and/or an inorganic acid; the alkali source is ammonia, aliphatic amine, aliphatic alcohol amine or quaternary ammonium base; the tin source is an oxide of tin, a stannic acid, a stannate, a halide of tin, a carbonate of tin, a nitrate of tin, a sulfate of tin, a phosphate of tin, or a hydroxide of tin, or a combination of two or three thereof.

Optionally, the second heat treatment liquid further contains a titanium source, wherein the titanium source is inorganic titanium salt and/or organic titanate;

preferably, the molar ratio of the catalyst containing the titanium silicalite molecular sieve to the titanium source is 100: (0.1-10), wherein the catalyst containing the titanium silicalite molecular sieve is SiO₂The titanium source is calculated as TiO₂And (6) counting.

A third aspect of the disclosure: there is provided the use of a tin titanium silicalite molecular sieve according to the first aspect of the disclosure in a phenol oxidation reaction.

A fourth aspect of the present disclosure: there is provided a phenol oxidation process comprising: under the condition of phenol oxidation, contacting phenol, an oxidant and an optional solvent with a catalyst for reaction, wherein the catalyst contains the tin-titanium-silicon molecular sieve of the first aspect of the disclosure;

preferably, the oxidant is peroxide, and the solvent is water, C1-C6 alcohol, C3-C8 ketone or C2-C6 nitrile; the molar ratio of the phenol to the oxidant is 1: (0.1-10), wherein the weight ratio of the phenol to the catalyst is 100: (0.2-50); the phenol oxidation conditions include: the temperature is 0-120 ℃, and the pressure is 0-5MPa in gauge pressure.

According to the technical scheme, the tin-titanium-silicon molecular sieve prepared by specific preparation steps (the steps of sequentially treating by using acid and alkali and combining heat treatment and the like) has a special physical and chemical characteristic structure, is favorable for diffusion of reactants and product molecules in a catalytic reaction, has a better catalytic effect when used for a reaction of phenol oxidation, and can effectively adjust the selectivity of a target product.

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

Detailed Description

The following describes in detail specific embodiments of the present disclosure. 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 disclosure: providing a tin-titanium-silicon molecular sieve, the molecular sieve comprising: tin element, titanium element, silicon element and oxygen element, wherein the molecular sieve satisfies X_1.1-2/X_0.5-1＝A，0.02<A<0.3, preferably 0.05<A<0.25，X_0.5-1The ratio of the pore diameter of the micropores of the molecular sieve in the range of 0.5-1nm to the distribution quantity of the total pore diameter, X_1.1-2Is the proportion of the pore diameter of the micropores of the molecular sieve in the range of 1.1-2nm in the distribution quantity of the pore diameter of the total micropores.

The molecular sieve provided by the disclosure has pore size distribution not only in the range of 0.5-1nm, but also in the range of 1.1-2nm, and the ratio of the proportion of the pore size distribution of micropores in the range of 1.1-2nm to the proportion of the pore size distribution of micropores in the range of 0.5-1nm to the pore size distribution of micropores in the range of 0.02-A<A<0.3, preferably, 0.05<A<0.25. When the molecular sieve adopting the preferred technical scheme disclosed by the disclosure is used for phenol oxidation reaction, the catalytic reaction is more favorably and stably carried out, the diffusion of reactant and product molecules in the process is more gradual, and the catalytic selectivity of the catalyst is favorably exerted. Not only can further improve the conversion rate of phenol, but also can more effectively modulate the selectivity of a target product (such as hydroquinone). In the present disclosure, the pore size of the micropores can be measured by conventional methods, and the present disclosure has no special requirement and is well known to those skilled in the art, for example, by using N₂Static adsorption and the like.

It is to be noted that, in particular, if the proportion of the pore size distribution of the micropores to the total pore size distribution is in the range of 1.1 to 2nm<At 1%, the pore distribution of the micropores is negligible, i.e. no micropore distribution in the range of 1.1-2nm is considered, as known to the person skilled in the art. Thus, the disclosure is said to be in N₂The pore diameter of the micropores in the range of 1.1-2nm in the static adsorption test means the proportion of the pore diameter distribution of the micropores in the range of 1.1-2nm to the total pore diameter distribution>1 percent. The microporous molecular sieve prepared by conventional direct hydrothermal synthesis has the ratio of the micropore size distribution to the total micropore size distribution in the range of 1.1-2nm<1% of microporous molecular sieve modified by common treatment modification method such as acid-base treatment, which is in the range of 1.1-2nmThe proportion of the pore size distribution of the micropores in the enclosure to the total pore size distribution is also low, generally<1％。

Further, the molecular sieve may satisfy I₉₆₀/I₈₀₀＝B，0.2<B<1，I₉₆₀The infrared absorption spectrum of the molecular sieve is 960cm^-1Absorption intensity in the vicinity, I₈₀₀The infrared absorption spectrum of the molecular sieve is 800cm^-1Absorption intensity in the vicinity, preferably, 0.3<B<0.8. Therefore, the method is more favorable for the diffusion of reactant and product molecules in the catalytic oxidation reaction, not only can further improve the conversion rate of raw materials, but also can more effectively modulate the selectivity of a target product. For example, when the catalyst is used in phenol oxidation reaction, the conversion rate of phenol can be further improved, and the selectivity of the target product can be more effectively adjusted.

In the present disclosure, the absorption intensity of the infrared absorption spectrum of the molecular sieve at a specific wave number and the pore size of the molecular sieve refer to the absorption intensity of the fourier transform infrared absorption spectrum of the molecular sieve at a specific wave number and the pore size in the molecular sieve, respectively, which are well known to those skilled in the art and are not described herein again.

In the present disclosure, the absorption intensity of the infrared absorption spectrum of the molecular sieve at a specific wave number is measured by using an infrared spectroscopy (IR), and the measurement method can be performed according to a conventional method, and the present disclosure has no special requirement, and is well known to those skilled in the art, and is not described herein in detail.

Further, the molecular sieve may satisfy T_w/T_k＝C，0.6<C<0.95, preferably 0.65<C<0.9, wherein, T_wIs the micropore volume of the molecular sieve, T_kIs the total pore volume of the molecular sieve. In the present disclosure, the pore volume can be measured by conventional methods, and the present disclosure is not particularly limited and is well known to those skilled in the art, for example, by using N₂Static adsorption and the like.

Further, the molar ratio of the silicon element, the titanium element and the tin element of the molecular sieve is 100: (0.1-10): (0.01-5), preferably 100: (0.2-5): (0.2-2.5). In the disclosure, the content of tin element and titanium element in the molecular sieve is measured by an X-ray fluorescence spectrum analysis (XRF). The test methods are performed according to conventional methods without special requirements, which are well known to those skilled in the art and will not be described herein.

Further, the surface silicon-titanium ratio of the molecular sieve is not lower than the bulk silicon-titanium ratio, wherein the silicon-titanium ratio refers to the molar ratio of silicon oxide to titanium oxide; more preferably, the ratio of the surface silicon-titanium ratio to the bulk silicon-titanium ratio is 1.2-5; still more preferably, the ratio of the surface silicon to titanium ratio to the bulk silicon to titanium ratio is 1.5 to 3.5. In the disclosure, the surface silicon-titanium ratio is determined by an X-ray photoelectron spectroscopy, and the bulk silicon-titanium ratio is determined by an X-ray fluorescence spectroscopy.

According to the present disclosure, the molecular sieve may be a molecular sieve having an MFI structure, a BEA structure, a MEL structure, or a MOR structure, etc.

In the preparation method of the tin-titanium-silicon molecular sieve provided by the disclosure, the pore size distribution of the tin-titanium-silicon molecular sieve can be adjusted by adjusting the adding amount of the first silicon source in the step (1) and the adding amount of the second silicon source in the step (2), and when SiO is used, the pore size distribution of the tin-titanium-silicon molecular sieve can be adjusted₂Counting the catalyst containing the titanium-silicon molecular sieve and the first silicon source in the step (1)The molar ratio is 100: (0.1-10), wherein the molar ratio of the catalyst containing the titanium silicalite molecular sieve in the step (1) to the second silicon source in the step (2) is 100: (5-50), the tin-titanium-silicon molecular sieve can satisfy X_1.1-2/X_0.5-1＝A，0.02<A<0.3。

The type of the titanium silicalite molecular sieve is not particularly limited in the present disclosure, and can be common titanium silicalite molecular sieves with various topological structures, such as: the titanium silicalite molecular sieve may be selected from one or more of a titanium silicalite molecular sieve of MFI structure (e.g., TS-1), a titanium silicalite molecular sieve of MEL structure (e.g., TS-2), a titanium silicalite molecular sieve of BEA structure (e.g., Ti-Beta), a titanium silicalite molecular sieve of MWW structure (e.g., Ti-MCM-22), a titanium silicalite molecular sieve of hexagonal structure (e.g., Ti-MCM-41, Ti-SBA-15), a titanium silicalite molecular sieve of MOR structure (e.g., Ti-MOR), a titanium silicalite molecular sieve of TUN structure (e.g., Ti-TUN), and a titanium silicalite molecular sieve of other structure (e.g., Ti-ZSM-48). Preferably, the titanium silicalite molecular sieve is selected from one or more of a titanium silicalite molecular sieve of an MFI structure, a titanium silicalite molecular sieve of an MEL structure and a titanium silicalite molecular sieve of a BEA structure. More preferably, the titanium silicalite molecular sieve is a titanium silicalite molecular sieve of MFI structure, such as TS-1 molecular sieve.

In the present disclosure, the catalyst containing the titanium silicalite molecular sieve may contain a fresh titanium silicalite molecular sieve, or may contain a titanium silicalite molecular sieve discharging agent, which is not particularly limited in the present disclosure.

Of course, from the perspective of preparation effect, the method of the present disclosure may use a fresh titanium silicalite as a raw material, but is not suitable from the perspective of cost control, and the like, and in order to save cost, the catalyst containing the titanium silicalite is preferably a discharging agent of a reaction device using the titanium silicalite as a catalyst.

The inventor of the present disclosure has characterized the physicochemical properties of the deactivated titanium-silicon molecular sieve, particularly the deactivated titanium-silicon molecular sieve deactivated in an alkaline environment, such as an ammoximation catalyst, after permanent deactivation, and finds that the crystal framework of the deactivated titanium-silicon molecular sieve is basically kept intact and can be utilized. The inventors of the present disclosure have made extensive studies and further found that, in the preparation process of a titanium silicalite, a deactivated titanium silicalite catalyst (especially, a titanium silicalite catalyst which is permanently deactivated under an alkaline condition, such as a deactivated cyclohexanone oximation catalyst, is used as a main raw material), and through specific preparation steps (using acid and alkali to sequentially perform treatment in combination with heat treatment, etc.), a tin-titanium silicalite molecular sieve with specific physicochemical characteristics can be obtained. The method not only utilizes the discharging agent, changes waste into valuable, has high molecular sieve yield, but also has excellent catalytic oxidation performance of the prepared molecular sieve, and can effectively modulate the selectivity of a target product particularly in the phenol oxidation reaction.

In the present disclosure, the discharging agent of the reaction apparatus using the titanium silicalite molecular sieve as the catalyst may be a discharging agent discharged from various apparatuses using the titanium silicalite molecular sieve as the catalyst, for example, a discharging agent discharged from an oxidation reaction apparatus using the titanium silicalite molecular sieve as the catalyst. The oxidation reaction may be various oxidation reactions, for example, the discharging agent of the reaction apparatus using the titanium silicalite molecular sieve as the catalyst may be a discharging agent of an ammoximation reaction apparatus and/or a discharging agent of an epoxidation reaction apparatus, specifically may be a discharging agent of a cyclohexanone ammoximation reaction apparatus and/or a discharging agent of a propylene epoxidation reaction apparatus, and preferably the discharging agent is a catalyst deactivated in an alkaline environment, and therefore, for the present disclosure, it is preferable that the discharging agent is a discharging agent of a cyclohexanone ammoximation reaction apparatus (for example, deactivated titanium silicalite TS-1, powdery, and having a particle size of 100-.

In the present disclosure, the discharging agent refers to a deactivated catalyst whose activity cannot be restored to 50% of the initial activity by a conventional regeneration method such as solvent washing or calcination (the initial activity refers to the average activity of the catalyst within 1h under the same reaction conditions, for example, in the actual cyclohexanone oximation reaction, the initial activity of the catalyst is generally 95% or more).

The activity of the discharging agent varies depending on its source. Preferably, the activity of the discharging agent is less than 50% of the activity of the titanium silicalite molecular sieve in a fresh state, and more preferably, the activity of the discharging agent can be 10-40% of the activity of the titanium silicalite molecular sieve in a fresh state. The activity of the titanium silicalite molecular sieve when fresh is generally more than 90 percent, and usually more than 95 percent.

In the present disclosure, the discharging agent may be derived from an industrial deactivator or a deactivated catalyst after reaction in a laboratory.

In the present disclosure, the discharging agent of each apparatus is determined by the reaction of each apparatus, and the discharging agent of the present disclosure is obtained as long as it is ensured that the activity of the discharging agent is lower than that of the fresh catalyst under the same reaction conditions in the same apparatus. As described above, the activity of the discharging agent is preferably 50% or less of the activity of the titanium silicalite molecular sieve in the fresh state.

In the present disclosure, taking the discharging agent of the cyclohexanone ammoximation reaction device as an example, the activity is determined by the following method:

taking a TS-1 molecular sieve (prepared by the method described in Zeolite, 1992, Vol.12: 943-950), TiO₂2.1%) was placed in a 100mL slurry bed reactor with continuous feed and membrane separation means, and a mixture of water and 30 wt% hydrogen peroxide (water to hydrogen peroxide volume ratio of 10: 9) a mixture of cyclohexanone and tert-butanol was added at a rate of 10.5mL/h (the volume ratio of cyclohexanone to tert-butanol was 1: 2.5) adding 36 wt% ammonia water at the speed of 5.7mL/h, simultaneously adding the three material flows, continuously discharging at the corresponding speed, maintaining the reaction temperature at 80 ℃, sampling the product after the reaction is stable, analyzing the liquid phase composition by using a gas chromatography method every 1 hour, calculating the conversion rate of cyclohexanone by using the following formula, and taking the conversion rate as the activity of the titanium-silicon molecular sieve. Conversion of cyclohexanone [ (molar amount of cyclohexanone charged-molar amount of unreacted cyclohexanone)/molar amount of cyclohexanone charged]X 100%. Wherein the result of 1h is taken as the initial activity.

According to the present disclosure, it is preferable that the method of the present disclosure further comprises: the discharging agent is roasted before being mixed with the first heat treatment liquid. The conditions for the firing can be selected from a wide range, and for the purposes of this disclosure preferred firing conditions include: the roasting temperature is 300-800 ℃, preferably 550-600 ℃; the roasting time is 2-12h, preferably 2-4h, and the roasting atmosphere comprises an air atmosphere; more preferably, the firing conditions include: firstly, roasting at 350-600 ℃ in a nitrogen atmosphere for 0.5-6h, and then roasting at 350-600 ℃ in an air atmosphere for 0.5-12 h.

According to the present disclosure, the first heat treatment in step (1) and the second heat treatment in step (2) are generally performed under autogenous pressure in a sealed condition without specific description.

According to the present disclosure, it is preferred that the temperature of the first heat treatment is 40 to 200 ℃, more preferably 50 to 180 ℃, and still more preferably 60 to 180 ℃. The time of the first heat treatment is preferably 1 to 240 hours, more preferably 2 to 120 hours.

According to the present disclosure, the temperature of the second heat treatment is preferably 120-180 ℃, more preferably 140-170 ℃. The time of the second heat treatment is preferably 2 to 48 hours, more preferably 6 to 24 hours.

In the preferred case of the present disclosure, in the second heat treatment process, the specific stages (1), (2) and (3) are adopted, and the obtained titanium silicalite molecular sieve is used for the reaction of phenol oxidation, which is more favorable for effectively modulating the selectivity of the target product.

Therefore, according to a preferred embodiment of the present disclosure, the second heat treatment is sequentially performed by the stage (1), the stage (2) and the stage (3), wherein the stage (1) is performed at 140 ℃ of 100-.

Further, the temperature difference between stage (3) and stage (2) is at least 20 ℃, preferably 25-60 ℃.

Further, the temperature rising rate from the room temperature to the stage (1) is 0.1-20 ℃/min, preferably 2-10 ℃/min; the temperature rising rate from the stage (1) to the stage (2) is 1-50 ℃/min, preferably 15-20 ℃/min; the cooling rate of the stage (2) to the stage (3) is 1-20 ℃/min, more preferably 10-20 ℃/min.

Further, it is preferable that the maintenance time of the stage (1) is 2 to 24 hours, preferably 4 to 16 hours; the maintenance time of stage (2) is 0.1 to 12 hours, preferably 2 to 6 hours; the holding time of stage (3) is 4 to 24 hours, preferably 4 to 12 hours.

According to the present disclosure, preferably, in SiO₂And (3) calculating the molar ratio of the catalyst containing the titanium silicalite molecular sieve in the step (1) to the second silicon source in the step (2) to be 100: (6-30), more preferably 100: (10-20). The adoption of the preferred embodiment of the disclosure is more beneficial to adjusting the micropore size distribution of the prepared tin-titanium-silicon molecular sieve, and the prepared tin-titanium-silicon molecular sieve is used in the phenol oxidation reaction process, so that the more stable catalytic effect of the reaction can be obtained.

According to the disclosure, preferably, the catalyst containing titanium silicalite molecular sieves: a tin source: acid: alkali source: the molar ratio of water is 100: (0.1-10): (0.005-50): (0.5-50): (20-1000), further preferably the catalyst comprising a titanium silicalite molecular sieve: a tin source: acid: alkali source: the molar ratio of water is 100: (0.5-2.0): (1-15): (1-20): (100-800), wherein the catalyst containing the titanium silicalite molecular sieve is SiO₂In terms of H, the acid is⁺The alkali source is counted as N when containing nitrogen element, and the alkali source is counted as OH when not containing nitrogen element^-And (6) counting.

According to the present disclosure, the acid may be selected from a wide range of species, which may be organic and/or inorganic acids, preferably inorganic acids; wherein, the inorganic acid can be one or more of hydrochloric acid, sulfuric acid, perchloric acid, nitric acid and phosphoric acid, and is preferably phosphoric acid; the organic acid can be C1-C10 organic carboxylic acid, preferably one or more of formic acid, acetic acid, propionic acid, naphthenic acid, peroxyacetic acid and peroxypropionic acid. The concentration of the acid in the acidic solution is greater than 0.1mol/L, preferably greater than or equal to 1mol/L, and more preferably from 1 to 15 mol/L. In the present disclosure, the main solvent of the acidic solution is water, and other solvents can be added according to the needs. The prepared Sn-Ti-Si molecular sieve has more obvious characteristics of pore volume and micropore distribution of 1.1-2 nm.

The first silicon source and the second silicon source are not particularly limited in the present disclosure, and may be any material capable of providing silicon element in the art, for example, the first silicon source and the second silicon source may be an organic silicon source and/or an inorganic silicon source, respectively.

Specifically, the organic silicon source may be one or more selected from silicon-containing compounds represented by formula I,

in the formula I, R₁、R₂、R₃And R₄Each is C₁-C₄Alkyl of (2) including C₁-C₄Straight chain alkyl of (2) and C₃-C₄Branched alkyl groups of (a), for example: r₁、R₂、R₃And R₄Each may be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl.

Further, the organic silicon source may be tetramethyl orthosilicate, tetraethyl orthosilicate, tetra-n-propyl orthosilicate, or tetra-n-butyl orthosilicate.

The optional range of the types of the inorganic silicon source is wide, and for the present disclosure, the inorganic silicon source is preferably silica sol and/or silica gel, and the silica gel or silica sol in the present disclosure may be silica gel or silica sol obtained by various production methods in various forms.

According to the present disclosure, the kind of the alkali source is wide in the selectable range, and may be an organic alkali source and/or an inorganic alkali source, wherein the inorganic alkali source may be ammonia, an alkali whose cation is an alkali metal, or an alkali whose cation is an alkaline earth metal, such as sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, potassium carbonate, barium hydroxide, etc., and the organic alkali source may be urea, an aliphatic amine compound, an aliphatic alcohol amine compound, or a quaternary ammonium alkali compound.

In the present disclosure, the quaternary ammonium base can be various organic quaternary ammonium bases and the aliphatic amine can be various NH₃In which at least one hydrogen is substituted with an aliphatic hydrocarbon group (preferably an alkyl group), which may be a variety of NH₃Wherein at least one hydrogen is substituted with a hydroxyl-containing aliphatic hydrocarbon group (preferably an alkyl group).

Specifically, the quaternary ammonium base may be a quaternary ammonium base represented by formula II, the aliphatic amine may be an aliphatic amine represented by formula III, and the aliphatic alcohol amine may be an aliphatic alcohol amine represented by formula IV:

in the formula II, R⁵、R⁶、R⁷And R⁸Each is C₁-C₄Alkyl of (2) including C₁-C₄Straight chain alkyl of (2) and C₃-C₄Branched alkyl groups of (a), for example: r⁵、R⁶、R⁷And R⁸Each may be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl.

R⁹(NH₂)_n(formula III)

In the formula III, n is an integer of 1 or 2. When n is 1, R⁹Is C₁～C₆Alkyl of (2) including C₁～C₆Straight chain alkyl of (2) and C₃-C₆Such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, isopentyl, tert-pentyl and n-hexyl. When n is 2, R⁹Is C₁-C₆Alkylene of (2) including C₁～C₆Linear alkylene of (A) and (C)₃～C₆Such as methylene, ethylene, n-propylene, n-butylene, n-pentylene or n-hexylene. More preferably, the aliphatic amine compound is ethylamine, n-butylamine, butanediamine or hexamethylenediamine, or a combination of two or three thereof.

(HOR¹⁰)_mNH_(3-m)(formula IV)

In the formula IV, m are R¹⁰Are the same or different and are each C₁-C₄Alkylene of (2) including C₁-C₄Linear alkylene of (A) and (C)₃-C₄Branched alkylene groups of (a), such as methylene, ethylene, n-propylene and n-butylene; m is 1, 2 or 3. More preferably, the aliphatic alcohol amine compound is monoethanolamine, diethanolamine or triethanolamine, or a combination of two or three thereof.

According to the present disclosure, in order to further improve the pore order of the synthesized tin-titanium-silicon molecular sieve, the alkali source is preferably selected from sodium hydroxide, ammonia water, ethylenediamine, n-butylamine, butanediamine, hexanediamine, monoethanolamine, diethanolamine, triethanolamine, tetraethylammonium hydroxide or tetrapropylammonium hydroxide, or a combination of two or three of them. The alkali source is preferably provided in the form of an alkali solution, more preferably an alkali solution having a pH > 9.

According to the present disclosure, the tin source is an inorganic compound of various tin, and for example, may be an oxide, a stannic acid, a stannate (corresponding salt of the aforementioned stannic acid), a halide, a carbonate, a nitrate, a sulfate, a phosphate or a hydroxide of tin, or a combination of two or three thereof, including but not limited to ammonium metastannate, sodium stannate, stannic chloride pentahydrate, stannous chloride hydrate, metastannic acid, calcium stannate, potassium stannate, lithium stannate, magnesium stannate, stannous sulfate, stannous pyrophosphate, stannic pyrophosphate, and the like. Ammonium meta-stannate, tin chloride, sodium stannate are used in the embodiments of the present disclosure as examples to illustrate the advantages of the present disclosure, but not to limit the present disclosure accordingly.

According to the present disclosure, preferably, the second heat treatment liquid further contains a titanium source. The molar ratio of the catalyst containing the titanium silicalite molecular sieve to the titanium source can be 100: (0.1-10), wherein the catalyst containing the titanium silicalite molecular sieve is SiO₂The titanium source is calculated as TiO₂And (6) counting. The titanium source may be of conventional choice in the art, and for the purposes of this disclosure, the titanium source is preferably an inorganic titanium salt and/or an organic titanate. The inorganic titanium salt may be a variety of hydrolysable titanium salts, and may be selected from, for example, TiX₄、TiOX₂Or Ti (SO)₄)₂And the like, wherein X is halogen, preferably chlorine, wherein preferably the inorganic titanium salt is TiCl₄、Ti(SO₄)₂Or TiOCl₂Or a combination of two or three of them. The organic titanate is preferably of the formula M₄TiO₄Wherein M is preferably an alkyl group having 1 to 4 carbon atoms, and 4M's may be the same or different, preferablyThe organic titanate is selected from isopropyl titanate, n-propyl titanate, tetrabutyl titanate or tetraethyl titanate, or a combination of two or three of the above. Titanium sulfate, tetrabutyl titanate, are used as examples in specific embodiments of the disclosure, but do not limit the scope of the disclosure accordingly.

According to the present disclosure, preferably, the method of the present disclosure further comprises a step of recovering a product from the heat-treated material of step (2). The step of recovering the product is a conventional method, is familiar to those skilled in the art, and is not particularly required herein, and generally refers to a process of filtering, washing, drying and calcining the product. Wherein the drying process can be carried out at a temperature between room temperature and 200 ℃, and the roasting process can be carried out at a temperature between 300 ℃ and 800 ℃ in a nitrogen atmosphere for 0.5-6 hours and then in an air atmosphere for 3-12 hours.

A third aspect of the disclosure: there is provided the use of a tin titanium silicalite molecular sieve according to the first aspect of the disclosure in a phenol oxidation reaction. In the phenol oxidation reaction, the molecular sieve disclosed by the invention can be used for effectively modulating the selectivity of a target product.

in accordance with the present disclosure, the oxidizing agent may be any of a variety of substances commonly available that are capable of oxidizing phenol. The method disclosed by the invention is particularly suitable for the occasion of oxidizing phenol by taking peroxide as an oxidizing agent, so that the effective utilization rate of the peroxide can be obviously improved. The peroxide is a compound containing an-O-O-bond in the molecular structure, and can be selected from hydrogen peroxide, organic peroxide and peracid. The organic peroxide is a substance obtained by substituting one or two hydrogen atoms in a hydrogen peroxide molecule with an organic group. The peracid refers to an organic oxyacid having an-O-O-bond in the molecular structure. Specific examples of the oxidizing agent in the present disclosure may include, but are not limited to: hydrogen peroxide, tert-butyl hydroperoxide, cumene peroxide, cyclohexyl hydroperoxide, peracetic acid and propionic acid. Preferably, the oxidizing agent is hydrogen peroxide, which further reduces the separation cost.

The hydrogen peroxide may be hydrogen peroxide in various forms commonly used in the art. From the viewpoint of further improving the safety of the method according to the present disclosure, the method according to the present disclosure preferably uses hydrogen peroxide in the form of an aqueous solution. In accordance with the methods of the present disclosure, when the hydrogen peroxide is provided as an aqueous solution, the concentration of the aqueous hydrogen peroxide solution may be a concentration conventional in the art, for example: 20-80 wt%. Aqueous solutions of hydrogen peroxide at concentrations meeting the above requirements may be prepared by conventional methods or may be obtained commercially, for example: can be 30 percent by weight of hydrogen peroxide, 50 percent by weight of hydrogen peroxide or 70 percent by weight of hydrogen peroxide which can be obtained commercially.

The amount of the oxidizing agent used may be conventionally selected according to the present disclosure, and is not particularly limited. Generally, the molar ratio of phenol to oxidant may be 1: (0.1-10), preferably 1: (0.2-5).

According to the method, the reaction speed can be adjusted through the content of the solvent, so that the reaction is more stable. The solvent may be various liquid substances capable of dissolving both phenol and an oxidizing agent or promoting mixing of both, and dissolving a target product. In general, the solvent may be selected from water, C₁-C₆Alcohol of (1), C₃-C₈Ketone and C₂-C₆A nitrile of (a). Specific examples of the solvent may include, but are not limited to: water, methanol, ethanol, n-propanol, isopropanol, tert-butanol, isobutanol, acetone, butanone and acetonitrile. Preferably, the solvent is acetone, methanol, water. When water is used as a solvent, the selectivity of the target product can be effectively adjusted. The amount of the solvent to be used may be appropriately selected depending on the amounts of the phenol and the oxidizing agent to be used. Generally, the molar ratio of the solvent to the phenol may be (0.1 to 100): 1, preferably (0.2-80): 1.

according to the present disclosure, the amount of the catalyst may be appropriately selected according to the amounts of the phenol and the oxidizing agent, for example, the weight ratio of the phenol to the catalyst may be 100: (0.2-50).

In general, the phenol oxidation reaction may be carried out at a temperature of from 0 to 120 ℃, preferably from 20 to 80 ℃ in accordance with the present disclosure; the pressure in the reactor may be in the range of 0 to 5MPa, preferably 0 to 3MPa, in terms of gauge pressure.

The method according to the present disclosure may further include separating the reaction mixture output from the fixed bed reactor to obtain the target product and unreacted reactants. The method for separating the reaction mixture may be a method conventionally selected in the art, and is not particularly limited. The separated unreacted reactant can be recycled.

The present disclosure is described in detail below with reference to examples, but the scope of the present disclosure is not limited thereby.

In the following examples and comparative examples, the reagents used were all commercially available analytical grade reagents, and the pressures were measured as gauge pressures.

The discharging agents of the following examples and comparative examples were obtained as follows, and the activity of titanium silicalite molecular sieves (including titanium silicalite discharging agents, and titanium silicalite fresheners) was measured by the following method.

Taking a TS-1 molecular sieve (prepared by the method described in Zeolite, 1992, Vol.12: 943-950), TiO₂2.1%) was placed in a 100mL slurry bed reactor with continuous feed and membrane separation means, and a mixture of water and 30 wt% hydrogen peroxide (water to hydrogen peroxide volume ratio of 10: 9) a mixture of cyclohexanone and tert-butanol was added at a rate of 10.5mL/h (the volume ratio of cyclohexanone to tert-butanol was 1: 2.5) adding 36 wt% ammonia water at the speed of 5.7mL/h, simultaneously adding the three material flows, continuously discharging at the corresponding speed, maintaining the reaction temperature at 80 ℃, sampling the product after the reaction is stable, analyzing the liquid phase composition by using a gas chromatography method every 1 hour, calculating the conversion rate of cyclohexanone by using the following formula, and taking the conversion rate as the activity of the titanium-silicon molecular sieve. Conversion of cyclohexanone [ (molar amount of cyclohexanone charged-molar amount of unreacted cyclohexanone)/molar amount of cyclohexanone charged]×100％。

The cyclohexanone conversion, measured for the first time, i.e. 1h, was its initial activity, which was 99.5%. After a period of about 168 hours, the cyclohexanone conversion rate is reduced from the initial 99.5% to 50%, the catalyst is separated and regenerated by roasting (roasting at 570 ℃ for 4 hours in an air atmosphere), and then the catalyst is continuously used in the cyclohexanone ammoximation reaction, and the steps are repeatedly carried out until the activity after regeneration is lower than 50% of the initial activity, at which time, the deactivated ammoximation catalyst sample is used as the discharging agent of the present disclosure, and the discharging agents SH-1 (the activity is 50%), SH-2 (the activity is 40%) are sequentially obtained according to the method.

The pore volume and pore size distribution of the sample were measured on a Micromeritics ASAP2405 static nitrogen adsorption apparatus, and the specific data are shown in Table 1.

The elemental compositions of the samples, such as tin, titanium, and silicon, were measured on a 3271E model X-ray fluorescence spectrometer, manufactured by Nippon Denshi electric motors Co., Ltd., and the data are shown in Table 1.

The surface Si/Ti ratios of the samples were measured by an ESCALB 250 type X-ray photoelectron spectrometer from Thermo Scientific, and the bulk Si/Ti ratios were measured by a 3271E type X-ray fluorescence spectrometer from Japan science and electric machines corporation, and are shown in Table 1.

The X-ray diffraction (XRD) crystallographic phase pattern measurements of the samples were carried out on a Siemens D5005X-ray diffractometer.

The Fourier transform infrared absorption spectrum of the sample is measured on a Nicolet 8210 type Fourier infrared spectrometer, KBr tablets are adopted under vacuum (the sample accounts for 1wt percent), and the test range is 400-^-1The specific data are shown in Table 1.

Comparative example 1

This comparative example illustrates a conventional process for preparing a titanium silicalite molecular sieve sample that does not contain tin using a silicon ester as a silicon source for hydrothermal crystallization.

Tetraethyl orthosilicate, titanium isopropoxide and tetrapropylammonium hydroxide are mixed, and proper amount of distilled water is added for stirring and mixing, wherein the molar composition in a reaction system is tetraethyl orthosilicate: titanium isopropoxide: tetrapropylammonium hydroxide: 100 parts of water: 5: 10: 200, wherein tetraethyl orthosilicate is SiO₂Counting; hydrolyzing at normal pressure and 60 deg.C for 1.0h, stirring at 75 deg.C for 3h, placing the mixed solution in a stainless steel sealed reaction kettle, and standing at 170 deg.C for 3d to obtain crystallized product mixture; filtering the mixture, washing with water, drying at 110 deg.C for 60min to obtain molecular sieve raw powder, and calcining at 550 deg.C for 3 hr to obtain titanium-silicon molecular sieve directly crystallized by hydrothermal method, wherein XRD crystal phase is MFI structure.

Comparative example 2

This comparative example illustrates the conventional process of preparing a titanium silicalite molecular sieve sample containing tin by direct hydrothermal crystallization using silicon ester as the silicon source.

Tetraethyl orthosilicate, ammonium metatitanate, titanium isopropoxide and tetrapropylammonium hydroxide are mixed, and a proper amount of distilled water is added for stirring and mixing, wherein the molar composition in a reaction system is tetraethyl orthosilicate: titanium isopropoxide: ammonium metastannate: tetrapropylammonium hydroxide: 100 parts of water: 5: 2: 10: 200, wherein tetraethyl orthosilicate is SiO₂Counting; hydrolyzing at normal pressure and 60 deg.C for 1.0h, stirring at 75 deg.C for 3h, placing the mixed solution in a stainless steel sealed reaction kettle, and standing at 170 deg.C for 3d to obtain crystallized product mixture; filtering the mixture, washing with water, drying at 110 deg.C for 60min to obtain molecular sieve raw powder, and calcining at 550 deg.C for 3h to obtain hydrothermally directly crystallized Sn-Ti-Si molecular sieve, wherein the XRD phase diagram of the molecular sieve is identical to that of comparative example 1 and has MFI structure.

Comparative example 3

This comparative example illustrates the process of impregnating a supported tin with a fresh sample of the titanium silicalite molecular sieve prepared in comparative example 1.

Mixing the titanium silicalite molecular sieve prepared in the comparative example 1 with an ammonium metastannate aqueous solution, wherein the mass ratio of the titanium silicalite molecular sieve to the ammonium metastannate to the water is 10:2:25, stirring for 6 hours at normal pressure and 60 ℃, filtering the mixture, washing with water, drying for 60 minutes at 110 ℃, and roasting for 3 hours at 550 ℃ to obtain the titanium silicalite molecular sieve loaded with tin, wherein the XRD crystalline phase of the titanium silicalite molecular sieve is of an MFI structure.

Comparative example 4

This comparative example illustrates the process of impregnating a loaded tin with a sample of discharging agent SH-1.

Mixing the discharging agent SH-1 with an ammonium metastannate aqueous solution, wherein the mass ratio of the titanium-silicon molecular sieve to the ammonium metastannate to water is 10:0.5:10, stirring for 12 hours at normal pressure and 40 ℃, then filtering the mixture, washing with water, drying for 60 minutes at 110 ℃, and roasting for 3 hours at 550 ℃ to obtain the titanium-silicon molecular sieve loaded with tin, wherein the XRD crystalline phase of the titanium-silicon molecular sieve is of an MFI structure.

Example 1

This example illustrates the methods and products provided by the present disclosure.

At normal temperature (20 ℃, the same in other comparative examples and examples) and normal pressure (0.1MPa, the same in other comparative examples and examples), firstly, mixing and pulping the deactivated cyclohexanone oximation catalyst SH-1 with 1mol/L hydrochloric acid aqueous solution containing a first silicon source of ethyl orthosilicate, and then mixing and stirring the mixed slurry at 80 ℃ for 12 hours, wherein the molar ratio of the catalyst SH-1 to the first silicon source is 100: 2; after solid-liquid separation, mixing the solid, a second silicon source of ethyl orthosilicate, a tin source of ammonium metatitanate, a titanium source of titanium sulfate and a sodium hydroxide aqueous solution (pH is 12), putting the mixed solution into a stainless steel sealed reaction kettle, and treating for 12 hours at 170 ℃, wherein the molar composition of the materials is an inactivated cyclohexanone oximation catalyst: a second silicon source: a titanium source: a tin source: acid: alkali: 100 parts of water: 15: 1: 1: 10: 5: 250, deactivated cyclohexanone oximation catalyst and silicon source are SiO₂Measured as H, acid⁺Calculated as OH, base^-The titanium source is calculated as TiO₂And (6) counting. The obtained product was filtered, washed with water, and dried at 110 ℃ for 120min, and then calcined at 550 ℃ for 3h to obtain a molecular sieve, whose XRD crystallography pattern is consistent with that of comparative example 1, indicating that a molecular sieve having MFI structure was obtained.

Comparative example 5

This comparative example illustrates the process of impregnating the loaded tin after acid treatment with the stripping agent SH-1.

Firstly, mixing and pulping the inactivated cyclohexanone oximation catalyst SH-1 and 1mol/L hydrochloric acid aqueous solution at normal temperature and normal pressure, and then mixing and stirring the mixed pulp at 80 ℃ for 12 hours; and (2) carrying out solid-liquid separation to obtain acid-treated SH-1, mixing the acid-treated SH-1 with an ammonium metastannate aqueous solution, wherein the mass ratio of the titanium silicalite molecular sieve to the ammonium metastannate to the water is 10:0.5:10, stirring for 12 hours at normal pressure and 40 ℃, filtering the mixture, washing with water, drying for 60 minutes at 110 ℃, and roasting for 3 hours at 550 ℃ to obtain the tin-loaded titanium silicalite molecular sieve, wherein the XRD crystalline phase of the tin-loaded titanium silicalite molecular sieve is of an MFI structure.

Comparative example 6

This comparative example illustrates a process in which the first thermal processing liquid does not contain a silicon source.

Mixing and pulping the inactivated cyclohexanone oximation catalyst SH-1 with 1mol/L hydrochloric acid aqueous solution at normal temperature and normal pressure, then mixing and stirring the mixed slurry at 80 ℃ for 12 hours, after solid-liquid separation, mixing the solid, a second silicon source of ethyl orthosilicate, a tin source of ammonium metastannate, a titanium source of titanium sulfate and a sodium hydroxide aqueous solution (pH is 12), then putting the mixed solution into a stainless steel sealed reaction kettle, and treating at 170 ℃ for 12 hours, wherein the molar composition of the materials is the inactivated cyclohexanone oximation catalyst: a second silicon source: a titanium source: a tin source: acid: alkali: 100 parts of water: 15: 1: 1: 10: 5: 250, deactivated cyclohexanone oximation catalyst and silicon source are SiO₂Measured as H, acid⁺Calculated as OH, base^-The titanium source is calculated as TiO₂And (6) counting. And filtering the obtained product, washing with water, drying at 110 ℃ for 120min, and roasting at 550 ℃ for 3h to obtain the molecular sieve, wherein the XRD crystalline phase of the molecular sieve is an MFI structure.

Comparative example 7

This comparative example illustrates a process in which the second thermal treatment solution does not contain a silicon source and a titanium source.

Under normal temperature and normal pressure, firstly mixing and pulping the inactivated cyclohexanone oximation catalyst SH-1 and 1mol/L hydrochloric acid aqueous solution containing ethyl orthosilicate as a first silicon source, and then mixing and stirring the mixed pulp at 80 ℃ for 12 hours, wherein the molar ratio of the catalyst SH-1 to the first silicon source is 100: 2; after solid-liquid separation, mixing the solid, tin source ammonium metattannate and sodium hydroxide aqueous solution (pH is 12), putting the mixed solution into a stainless steel sealed reaction kettle, and treating for 12 hours at 170 ℃, wherein the molar composition of the materials is an inactivated cyclohexanone oximation catalyst: a tin source: acid: alkali: 100 parts of water: 1: 10: 5: 250, deactivated cyclohexanone oximation catalyst and silicon source are SiO₂Measured as H, acid⁺Metering alkaliWith OH^-And (6) counting. And filtering the obtained product, washing with water, drying at 110 ℃ for 120min, and roasting at 550 ℃ for 3h to obtain the molecular sieve, wherein the XRD crystalline phase of the molecular sieve is an MFI structure.

Example 2

Under normal temperature and normal pressure, firstly mixing and pulping the inactivated cyclohexanone oximation catalyst SH-2 and 1mol/L hydrochloric acid aqueous solution containing first silicon source silica gel, and then mixing and stirring the mixed pulp at 80 ℃ for 12 hours, wherein the molar ratio of the catalyst SH-2 to the first silicon source is 100: 1; after solid-liquid separation, mixing the solid, a second silicon source of ethyl orthosilicate, a tin source of stannic chloride, a titanium source of titanium sulfate and a sodium hydroxide aqueous solution (pH is 12), putting the mixed solution into a stainless steel sealed reaction kettle, and treating for 12 hours at 170 ℃, wherein the molar composition of the materials is an inactivated cyclohexanone oximation catalyst: a second silicon source: a titanium source: a tin source: acid: alkali: 100 parts of water: 15: 1: 1: 10: 5: 250, deactivated cyclohexanone oximation catalyst and silicon source are SiO₂Measured as H, acid⁺Calculated as OH, base^-The titanium source is calculated as TiO₂And (6) counting. The obtained product was filtered, washed with water, and dried at 110 ℃ for 120min, and then calcined at 550 ℃ for 3h to obtain a molecular sieve, whose XRD crystallography pattern is consistent with that of comparative example 1, indicating that a molecular sieve having MFI structure was obtained.

Example 3

Under normal temperature and normal pressure, firstly mixing and pulping the inactivated cyclohexanone oximation catalyst SH-1 and 5mol/L sulfuric acid aqueous solution containing ethyl orthosilicate as a first silicon source, and then mixing and stirring the mixed slurry at 120 ℃ for 2 hours, wherein the molar ratio of the catalyst SH-1 to the first silicon source is 100: 15; after solid-liquid separation, mixing the solid, a second silicon source of ethyl orthosilicate, a tin source of sodium stannate, a titanium source of titanium sulfate and an n-butylamine aqueous solution (pH is 12.0), putting the mixed solution into a stainless steel sealed reaction kettle, and treating for 12 hours at 170 ℃, wherein the molar composition of the materials is an inactivated cyclohexanone oximation catalyst: a second silicon source: a titanium source: a tin source: acid: alkali: water ═ water100: 6: 1: 0.1: 0.5: 0.5: 50, deactivated cyclohexanone oximation catalyst and silicon source are SiO₂Measured as H, acid⁺Calculated by alkali in N and titanium source in TiO₂And (6) counting. The obtained product is filtered, washed by water, dried at 110 ℃ for 120min and then roasted at 550 ℃ for 3h to obtain the molecular sieve, and the XRD crystal phase diagram of the molecular sieve is consistent with that of the molecular sieve in the comparative example 1.

Example 4

Under normal temperature and normal pressure, firstly mixing and pulping the inactivated cyclohexanone oximation catalyst SH-1 and a 12mol/L acetic acid aqueous solution containing a first silicon source of tetraethoxysilane, and then mixing and stirring the mixed pulp at 160 ℃ for 6 hours, wherein the molar ratio of the catalyst SH-1 to the first silicon source is 100: 0.8; after solid-liquid separation, mixing the solid, a second silicon source of ethyl orthosilicate, a tin source of ammonium metatitanate, a titanium source of titanium oxychloride and a diethanolamine aqueous solution (pH is 12), putting the mixed solution into a stainless steel sealed reaction kettle, and treating for 24 hours at 170 ℃, wherein the molar composition of the materials is an inactivated cyclohexanone oximation catalyst: a second silicon source: a titanium source: a tin source: acid: alkali: 100 parts of water: 30: 10: 6: 20: 25: 900 deactivated cyclohexanone oximation catalyst and silicon source with SiO₂The silicon source is SiO₂Measured as H, acid⁺Calculated by alkali in N and titanium source in TiO₂And (6) counting. The product was then recovered according to the procedure of example 1 to obtain a molecular sieve having an XRD crystallographic phase diagram in accordance with comparative example 1.

Example 5

A molecular sieve was prepared according to the method of example 1, except that the feed molar composition was a deactivated cyclohexanone oximation catalyst: the second silicon source is 100: 50, the XRD crystallographic phase diagram of the sample obtained is consistent with that of comparative example 1.

Example 6

A molecular sieve was prepared according to the method of example 1, except that the feed molar composition was a deactivated cyclohexanone oximation catalyst: the second silicon source is 100: 5, the XRD crystallographic phase diagram of the obtained sample is consistent with that of comparative example 1.

Example 7

A molecular sieve was prepared as in example 1, except that the discharger SH-1 was calcined and then subjected to subsequent pulping and heat treatment processes, wherein the calcination conditions included: the sample was calcined at 570 ℃ for 4 hours in an air atmosphere, and the XRD crystal phase diagram of the obtained sample was consistent with that of comparative example 1.

Example 8

A molecular sieve was prepared according to the method of example 1, except that the conditions of the first heat treatment were: the mixed slurry was treated with mixing and stirring at 190 ℃ for 3 hours, and the XRD crystal phase diagram of the obtained sample was in accordance with that of comparative example 1.

Example 9

A molecular sieve was prepared according to the method of example 1, except that the second heat treatment liquid did not contain a titanium source, i.e., the solid, silicon source tetraethoxysilane, tin source ammonium metastannate and sodium hydroxide aqueous solution (pH 12) were mixed, and the mixture was put into a stainless steel sealed reaction vessel and treated at 170 ℃ for 12 hours, wherein the molar composition of the materials was deactivated cyclohexanone oximation catalyst: a second silicon source: a tin source: acid: alkali: 100 parts of water: 15: 1: 10: 5: 250. the XRD crystallography pattern of the obtained sample was consistent with that of comparative example 1.

Example 10

A molecular sieve was prepared according to the procedure of example 1, except that phosphoric acid was used instead of hydrochloric acid. The XRD crystallography pattern of the obtained sample was consistent with that of comparative example 1.

Example 11

A molecular sieve was prepared as in example 1 except that the second heat treatment employed a specific treatment procedure, specifically as follows: putting the mixed solution into a stainless steel sealed reaction kettle, and sequentially treating for 6 hours at the temperature of 125 ℃ and the autogenous pressure (stage (1)); hydrothermal treatment at 180 ℃ and autogenous pressure for 2 hours (stage (2)); hydrothermal treatment at 150 ℃ and autogenous pressure for 4 hours (stage (3)), the rate of temperature rise from room temperature to stage (1) being 2 ℃/min, the rate of temperature rise from stage (1) to stage (2) being 15 ℃/min, and the rate of temperature decrease from stage (2) to stage (3) being 10 ℃/min. The obtained product was filtered, washed with water, and dried at 110 ℃ for 120min, and then calcined at 550 ℃ for 3h to obtain a molecular sieve, whose XRD crystallography pattern is consistent with that of comparative example 1, indicating that a molecular sieve having MFI structure was obtained.

Example 12

A molecular sieve was prepared as in example 1 except that the second heat treatment employed a specific treatment procedure, specifically as follows: putting the mixed solution into a stainless steel sealed reaction kettle, and performing hydrothermal treatment for 4 hours at the temperature of 130 ℃ and the autogenous pressure in sequence (stage (1)); hydrothermal treatment at 200 ℃ and autogenous pressure for 4 hours (stage (2)); hydrothermal treatment at 140 ℃ and autogenous pressure for 12 hours (stage (3)), the rate of temperature rise from room temperature to stage (1) being 10 ℃/min, the rate of temperature rise from stage (1) to stage (2) being 20 ℃/min, and the rate of temperature decrease from stage (2) to stage (3) being 10 ℃/min. The obtained product was filtered, washed with water, and dried at 110 ℃ for 120min, and then calcined at 550 ℃ for 3h to obtain a molecular sieve, whose XRD crystallography pattern is consistent with that of comparative example 1, indicating that a molecular sieve having MFI structure was obtained.

Example 13

A molecular sieve was prepared as in example 1 except that the second heat treatment employed a specific treatment procedure, specifically as follows: putting the mixed solution into a stainless steel sealed reaction kettle, and performing hydrothermal treatment for 18 hours at the temperature of 120 ℃ and the autogenous pressure in sequence (stage (1)); hydrothermal treatment at 190 ℃ and autogenous pressure for 8 hours (stage (2)); carrying out hydrothermal treatment for 14 hours at the temperature of 180 ℃ and the autogenous pressure (stage (3)), wherein the temperature rising rate from the room temperature to the stage (1) is 10 ℃/min, the temperature rising rate from the stage (1) to the stage (2) is 20 ℃/min, and the temperature falling rate from the stage (2) to the stage (3) is 10 ℃/min. The obtained product was filtered, washed with water, and dried at 110 ℃ for 120min, and then calcined at 550 ℃ for 3h to obtain a molecular sieve, whose XRD crystallography pattern is consistent with that of comparative example 1, indicating that a molecular sieve having MFI structure was obtained.

TABLE 1

In table 1:

A＝X_1.1-2/X_0.5-1，X_0.5-1the ratio of the pore diameter of the micropores of the molecular sieve in the range of 0.5-1nm to the distribution quantity of the total pore diameter, X_1.1-2The proportion of the micropore diameter of the molecular sieve in the range of 1.1-2nm to the total micropore diameter distribution amount is adopted;

B＝I₉₆₀/I₈₀₀，I₉₆₀the infrared absorption spectrum of the molecular sieve is 960cm^-1Absorption intensity in the vicinity, I₈₀₀The infrared absorption spectrum of the molecular sieve is 800cm^-1Absorption strength in the vicinity;

C＝T_w/T_k，T_wis the micropore volume of the molecular sieve, T_kIs the total pore volume of the molecular sieve;

silicon: titanium: tin refers to the element silicon: titanium element: molar ratio of tin element.

As can be seen from the results in table 1, the molecular sieves prepared by the preferred method of the present disclosure have a pore size distribution, a ratio of micropore pore volume to total pore volume, elemental silicon: titanium element: the molar ratio of tin element, the ratio of surface silicon to titanium and bulk silicon to titanium, and other data fully satisfy all the characteristics of the product disclosed. In contrast, in the case of the titanium-silicon molecular sieve containing no tin prepared by using silicate as a silicon source in comparative example 1, the titanium-silicon molecular sieve containing tin directly prepared by using silicate as a silicon source in comparative example 2, the titanium-silicon molecular sieve containing tin prepared by using the titanium-silicon molecular sieve prepared in comparative example 1 in comparative example 3, or the tin-titanium-silicon molecular sieve obtained by using a discharging agent to load tin in comparative example 4, the tin-titanium-silicon molecular sieve obtained by using a discharging agent to load tin after acid treatment in comparative example 5, the tin-titanium-silicon molecular sieve obtained by using a first heat treatment liquid containing no first silicon source in comparative example 6, and the tin-titanium-silicon molecular sieve obtained by using a second heat treatment liquid containing no second silicon source and a titanium source in comparative example 7, the data such as the pore size distribution, the ratio of the pore volume of micropores to the total pore volume, and the.

Test examples

This test example is intended to illustrate the reaction effect of the molecular sieve obtained by the method provided in the present disclosure and the molecular sieve obtained by the method of comparative example for the oxidation reaction of phenol.

The catalyst (molecular sieves prepared in examples and comparative examples, comparative fresh titanium silicalite molecular sieves), phenol, hydrogen peroxide (provided in the form of 30 wt% hydrogen peroxide) as an oxidant and acetone as a solvent were mixed to form a liquid mixture, and the liquid mixture was filled in a slurry bed reactor. Wherein the molar ratio of phenol to hydrogen peroxide is 2: 1, the molar ratio of phenol to solvent is 1: the reaction temperature was 70 ℃, the composition of the reaction mixture in the reactor was monitored during the reaction by gas chromatography and the relative amounts of phenol conversion and hydroquinone selectivity increase in the product were calculated and the results obtained for 0.5 hours and 8 hours of reaction are shown in table 2.

Phenol conversion% (% of phenol converted in the reaction mass/mass of phenol charged × 100%)

The relative increase in hydroquinone selectivity is the increase in hydroquinone selectivity of the tin titanium silicalite molecular sieve of the example over the hydroquinone selectivity of the fresh titanium silicalite molecular sieve over the same reaction time.

TABLE 2

As can be seen from the data in table 2, the molecular sieve with a specific physicochemical characteristic structure of the present disclosure has a high phenol conversion rate after being used for the reaction of phenol oxidation for 8 hours, and is particularly beneficial to modulating the selectivity of a target product with a high added value, and can obtain a good catalytic effect.

The preferred embodiments of the present disclosure have been described in detail above, 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 fall within 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. A tin-titanium-silicon molecular sieve, comprising: tin element, titanium element, silicon element and oxygen element, wherein the molecular sieve satisfies X_1.1-2/X_0.5-1＝A，0.02<A<0.3, preferably 0.05<A<0.25，X_0.5-1The ratio of the pore diameter of the micropores of the molecular sieve in the range of 0.5-1nm to the distribution quantity of the total pore diameter, X_1.1-2Is the proportion of the pore diameter of the micropores of the molecular sieve in the range of 1.1-2nm in the distribution quantity of the pore diameter of the total micropores.

2. The molecular sieve of claim 1, wherein the molecular sieve satisfies I₉₆₀/I₈₀₀＝B，0.2<B<1，I₉₆₀The infrared absorption spectrum of the molecular sieve is 960cm^-1Absorption intensity in the vicinity, I₈₀₀The infrared absorption spectrum of the molecular sieve is 800cm^-1Absorption intensity in the vicinity, preferably, 0.3<B<0.8。

3. The molecular sieve of claim 1, wherein said zeolite is selected from the group consisting of zeolite, and zeolite,wherein the molecular sieve satisfies T_w/T_k＝C，0.6<C<0.95，T_wIs the micropore volume of the molecular sieve, T_kIs the total pore volume of the molecular sieve, preferably, 0.65<C<0.9。

4. The molecular sieve of claim 1, wherein the molecular sieve has a molar ratio of elemental silicon, elemental titanium, and elemental tin of 100: (0.1-10): (0.01-5), preferably 100: (0.2-5): (0.2-2.5).

5. The molecular sieve of claim 1, wherein the molecular sieve has a surface silicon to titanium ratio of not less than a bulk silicon to titanium ratio, the silicon to titanium ratio being the molar ratio of silicon oxide to titanium oxide;

6. The molecular sieve of claim 1, wherein the molecular sieve is a molecular sieve of MFI structure, a molecular sieve of BEA structure, a molecular sieve of MEL structure, or a molecular sieve of MOR structure.

7. A method of preparing the tin titanium silicalite molecular sieve of any one of claims 1 to 6, comprising:

wherein, SiO is used₂And (2) calculating the molar ratio of the catalyst containing the titanium silicalite molecular sieve to the first silicon source in the step (1) to be 100: (0.1-10), step (ii)The molar ratio of the catalyst containing the titanium silicalite molecular sieves in the step (1) to the second silicon source in the step (2) is 100: (5-50).

8. The method according to claim 7, wherein the catalyst containing the titanium silicalite molecular sieve in the step (1) is a discharging agent of a reaction device using the titanium silicalite molecular sieve as the catalyst, preferably a discharging agent of an ammoximation reaction device;

9. The method as claimed in claim 7, wherein the second heat treatment is sequentially performed in stages (1), (2) and (3), wherein the stage (1) is maintained at 140 ℃ for 2-24 hours at 100-; preferably, the temperature difference between stage (3) and stage (2) is at least 20 ℃, preferably 25-60 ℃; preferably, the temperature rising rate from room temperature to the stage (1) is 0.1-20 ℃/min, the temperature rising rate from the stage (1) to the stage (2) is 1-50 ℃/min, and the temperature falling rate from the stage (2) to the stage (3) is 1-20 ℃/min.

10. The process of claim 7, wherein the catalyst comprising titanium silicalite molecular sieves: a tin source: acid: alkali source: the molar ratio of water is 100: (0.1-10): (0.005-50): (0.5-50): (20-1000), wherein the catalyst containing the titanium silicalite molecular sieve is SiO₂In terms of H, the acid is⁺The alkali source is counted as N when containing nitrogen element, and the alkali source is counted as OH when not containing nitrogen element^-Counting;

11. The method of claim 7, wherein the second heat treatment liquid further contains a titanium source, the titanium source being an inorganic titanium salt and/or an organic titanate;

12. Use of a tin titanium silicalite molecular sieve as claimed in any one of claims 1 to 6 in a phenol oxidation reaction.

13. A phenol oxidation process, comprising: under the condition of phenol oxidation, phenol, an oxidant and an optional solvent are contacted with a catalyst for reaction, and the catalyst is characterized by containing the tin-titanium-silicon molecular sieve as claimed in any one of claims 1 to 6;