CN107537559B - A kind of titanium-containing silicon molecular sieve catalyst and its preparation method and application - Google Patents

Abstract

The invention relates to the field of titanium-silicon molecular sieves, and particularly provides a preparation method of a titanium-silicon-containing molecular sieve catalyst, which comprises the following steps: (1) contacting a discharging agent with an organic compound to obtain a contacted product, wherein the organic compound is selected from one or more of sulfone, ketone and amide, and the discharging agent is the discharging agent of a reaction device which takes a titanium silicalite molecular sieve as a catalyst active component; (2) in the presence of an aqueous solvent, mixing the contacted product with an alkali source, and then carrying out hydrothermal treatment. The invention provides a catalyst obtained by the method. The invention provides the application of the catalyst in oxidation reaction. The relative crystallinity and micropore specific surface area of the titanium-silicon molecular sieve in the discharging agent are recovered, and the organic compound can be recycled by simple separation, thereby reducing the pollution of the preparation process to the environment. The invention does not need to be regenerated at high temperature, effectively saves energy consumption and is very suitable for industrial application.

Description

A kind of titanium-containing silicon molecular sieve catalyst and its preparation method and application

technical field

The present invention relates to a titanium-silicon molecular sieve catalyst and its preparation method and application.

Background technique

Titanium silica molecular sieve is a new type of heteroatom molecular sieve developed in the early 1980s. At present, TS-1 with MFI structure, TS-2 with MEL structure, and TS-48 with larger pore structure have been synthesized. Such molecular sieves have excellent selective oxidation performance and high catalytic activity for many organic oxidation reactions, such as epoxidation of olefins, hydroxylation of aromatic hydrocarbons, oximation of cyclohexanone, and oxidation of alcohols. They are used as redox molecular sieves. The catalyst has good application prospects.

Among them, TS-1 molecular sieve is a new type of titanium-silicon molecular sieve with excellent catalytic selective oxidation performance formed by introducing transition metal element titanium into the molecular sieve framework with 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 ZSM-5 molecular sieve. Since TS-1 molecular sieve can use non-polluting low-concentration hydrogen peroxide as the oxidant in the oxidation reaction of organic matter, it avoids the problems of complicated oxidation process and environmental pollution, and has unparalleled energy saving, economy and environment of traditional oxidation systems. It has the advantages of friendliness and good reaction selectivity, so it has great industrial application prospects. However, the catalytic performance of titanium-silicon molecular sieves usually deteriorates and deactivation occurs after a period of operation. The cause of deactivation may be due to the accumulation of impurities or reaction by-products in the catalyst micropores during the synthesis of molecular sieves.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a preparation method of a titanium-silicon molecular sieve catalyst different from the prior art, which not only saves energy consumption and cost, but also greatly reduces the environmental pollution caused by the preparation process.

In order to achieve the foregoing object, according to the first aspect of the present invention, the present invention provides a preparation method of a titanium-containing silicon molecular sieve catalyst, the method comprising:

(1) contacting an unloading agent with an organic compound to obtain a contacted product, the organic compound is selected from one or more of sulfones, ketones and amides, and the unloading agent is a catalyst active group using titanium-silicon molecular sieves The discharge agent of the separate reaction device;

(2) In the presence of an aqueous solvent, the contacted product and the alkali source are mixed and then subjected to hydrothermal treatment.

According to a second aspect of the present invention, the present invention provides a catalyst obtained according to the method of the present invention.

According to a third aspect of the present invention, the present invention provides the application of the catalyst of the present invention in an oxidation reaction.

According to the preparation method provided by the invention, the relative crystallinity and microporous specific surface area of the active component titanium-silicon molecular sieve in the unloading agent are recovered, the activity and activity stability are good, and the unloading agent can basically reach the activity when fresh.

According to the method of the present invention, the used organic compounds can be recycled through simple separation, which greatly reduces the environmental pollution caused by the preparation process.

The method can basically completely recover the activity, crystallinity and micropore specific surface area of the prepared catalyst without regeneration at high temperature, effectively saves energy consumption, and is very suitable for industrial application.

Other features and advantages of the present invention will be described in detail in the detailed description that follows.

Detailed ways

Specific embodiments of the present invention will be described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, but not to limit the present invention.

As mentioned above, the present invention provides a method for preparing a titanium-silicon molecular sieve catalyst, the method comprising: (1) contacting an unloading agent with an organic compound to obtain a contacted product, wherein the organic compound is selected from sulfones, ketones and one or more of amides, and the discharge agent is the discharge agent of the reaction device using titanium-silicon molecular sieve as the catalyst active component; (2) in the presence of an aqueous solvent, mix the contacted product alkali source After hydrothermal treatment.

According to the method of the present invention, the object of the present invention can be achieved by following the aforementioned scheme, and organic compounds meeting the aforementioned requirements can be used in the present invention. For the present invention, preferably the organic compounds are sulfoxide, sulfone, alkanone and amide one or more of.

According to the method of the present invention, more preferably the organic compound is one of dimethyl sulfoxide, sulfolane, N-methylpyrrolidone, N,N-dimethylformamide and N,N-dimethylacetamide or more.

In the present invention, the unloading agent of the reaction device using titanium-silicon molecular sieve as the catalyst active component can be the unloading agent discharged from various devices using titanium-silicon molecular sieve as the catalyst active component. The agent can be a discharge agent in a device that uses titanium-silicon molecular sieve directly as a catalyst, or it can be an active component that uses titanium-silicon molecular sieve as a shaped catalyst (the catalyst is a shaped catalyst, for example, it can also include a matrix and a binder, etc.) The discharge agent discharged from the device.

In the present invention, the unloading agent may be, for example, the unloading agent unloaded from an oxidation reaction device using titanium-silicon molecular sieve as a catalyst active component. The oxidation reaction can be various oxidation reactions, for example, the unloading agent of the reaction device using titanium-silicon molecular sieve as the catalyst active component can be the unloading agent of the ammoximation reaction device and the unloading agent of the hydroxylation reaction device. and one or more of the unloading agent of the epoxidation reaction device, specifically the unloading agent of the cyclohexanone ammoximation reaction device, the unloading agent of the phenol hydroxylation reaction device and the propylene epoxidation reaction device One or more of the unloading agents, preferably the unloading agent is a catalyst that is deactivated by the reaction in an alkaline environment, therefore, for the present invention, preferably the unloading agent is a cyclohexanone ammoximation reaction device. Unloading agent (such as deactivated titanium silicon molecular sieve TS-1, powder, particle size is 100-500nm).

In the present invention, the unloading agent refers to a deactivated catalyst whose activity cannot be restored to 50% of the initial activity by conventional regeneration methods such as solvent washing or calcination (the initial activity refers to under the same reaction conditions, The average activity of the catalyst within 1h. For example, in the actual cyclohexanone oximation reaction, the initial activity of the catalyst should reach more than 95%).

The activity of the unloading agent varies according to its source. Generally, the activity of the unloading agent may be 5-95% of the activity when fresh (ie, the activity of the fresh agent). Preferably, the activity of the unloading agent may be 50% or less of the activity when fresh, and further preferably, the activity of the unloading agent may be 10-40% of the activity when fresh. The activity of the fresh agent is generally above 90%, usually above 95%.

In the present invention, the unloading agent can be derived from an industrial deactivator or a deactivated catalyst after the reaction is carried out in the laboratory.

In the present invention, the unloading agent of each device is measured by the reaction of each device, as long as it is ensured that in the same device and under the same reaction conditions, the activity of the unloading agent is lower than that of the fresh agent, which is the invention remover. As previously mentioned, preferably, the activity of the unloading agent is less than 50% of the activity of the fresh agent.

In the present invention, taking the discharge agent of the cyclohexanone ammoximation reaction device as an example, the activity is measured by the following method:

Take TS-1 molecular sieve (prepared by the method described in "Zeolites, 1992, Vol.12: 943-950", the mass percentage of TiO ₂ is 2.1%) and placed in a 100 mL chamber with continuous feeding and membrane separation device. In the slurry bed reactor, a mixture of water and 30 wt% hydrogen peroxide (the volume ratio of water and hydrogen peroxide is 10:9) was added at a rate of 5.7 mL/h under stirring, and the mixture was stirred at a rate of 10.5 mL/h. The mixture of cyclohexanone and tert-butanol was added at a speed (the volume ratio of cyclohexanone and tert-butanol was 1:2.5), 36wt% ammonia water was added at a speed of 5.7mL/h, and the above-mentioned three streams were added simultaneously. The corresponding speed is continuously discharged, and the reaction temperature is maintained at 80 ° C. After the reaction is stable, the product is sampled every 1 hour and the composition of the liquid phase is analyzed by gas chromatography. The following formula is used to calculate the conversion rate of cyclohexanone and use it as Activity of titanium-silicon molecular sieves. Conversion rate of cyclohexanone=[(molar amount of cyclohexanone added−molar amount of unreacted cyclohexanone)/molar amount of cyclohexanone added]×100%. Among them, the 1h result was taken as the initial activity.

According to the method of the present invention, the titanium-silicon molecular sieve in the unloading agent can be a titanium-silicon molecular sieve with an MFI structure (such as TS-1), a titanium-silicon molecular sieve with a MEL structure (such as TS-2), or a titanium-silicon molecular sieve with a BEA structure (such as Ti-Beta), MWW structure titanium silicon molecular sieve (such as Ti-MCM-22), two-dimensional hexagonal structure titanium silicon molecular sieve (such as Ti-MCM-41, Ti-SBA-15), MOR structure titanium silicon At least one of molecular sieves (such as Ti-MOR), titanium-silicon molecular sieves of TUN structure (such as Ti-TUN) and titanium-silicon molecular sieves of other structures (such as Ti-ZSM-48). Preferably, the titanium-silicon molecular sieve is one or more of MFI-structured titanium-silicon molecular sieves, MEL-structured titanium-silicon molecular sieves and BEA-structured titanium-silicon molecular sieves, more preferably MFI-structured titanium-silicon molecular sieves, more preferably Preferably, the titanium-silicon molecular sieve is an MFI-structured titanium-silicon molecular sieve with hollow crystal grains, and the radial length of the cavity portion of the hollow structure is 5-300 nm.

According to the method of the present invention, preferably, the unloading agent of the reaction device using the titanium-silicon molecular sieve as the catalyst active component is the unloading agent of the ammoximation reaction device; preferably, the titanium-silicon molecular sieve has an MFI structure, and the unloading agent The activity of the agent is less than 50% of the activity when fresh.

According to the method of the present invention, preferably in step (1), the contacting temperature is lower than the boiling point of the organic compound, preferably 20-250° C. lower than the boiling point of the organic compound. With the use of different organic compounds, the contacting temperature And there is a difference. For example, under standard pressure, the boiling points of dimethyl sulfoxide, sulfolane, N-methylpyrrolidone, N,N-dimethylformamide and N,N-dimethylacetamide are 189°C, 285°C, and 202°C, respectively. , 153°C and 96°C.

According to the method of the present invention, the boiling point of the organic compound refers to the boiling point of the single organic compound used. If more than one organic compound is used, the boiling point is the one with the lowest boiling point.

The present invention has no special requirements on the contact pressure in step (1), preferably 0.001-1.0 MPa.

According to the method of the present invention, preferably, the contacting in the step (1) is carried out in the presence of ammonia, and the mass ratio of ammonia to the organic compound is (0.0001-0.1):1. According to the aforementioned technical solution, the preparation time can be saved, and the catalytic effect of the catalyst can be further improved.

Wherein, ammonia can be introduced in the form of liquid ammonia, also in the form of an aqueous solution, or in the form of gas. The concentration of ammonia in the form of an aqueous solution (ie, ammonia water) is not particularly limited, and may be conventionally selected, for example, 1 to 36% by weight.

According to the method of the present invention, the ratio of the above-mentioned organic compound to the unloading agent is not strictly limited, as long as the object of the present invention can be achieved. Considering the convenience of operation and saving of raw materials, it is preferred that in step (1), the mass ratio of the organic compound to the discharge agent is (0.5-100): 1, more preferably (2-50): 1, more preferably (5-25):1.

According to the method of the present invention, the contacted product in step (1) may be a mixture obtained by direct contact, or a contacted solid product obtained by separation, and the solid product may be dried or not dried. Step (2), preferably after a drying step, the drying conditions include: the temperature is 80-300° C., and the drying time is subject to drying to a constant weight, which can be adjusted as needed. Wherein, the separation step generally includes: filtration, washing and other conventional steps. I won't go into details here.

According to the method of the present invention, preferably in step (2), the conditions of hydrothermal treatment include: pH value is 8-14, preferably 10-13.

According to the method of the present invention, preferably in step (2), the conditions of hydrothermal treatment include: the temperature is 120-200°C, preferably 150-170°C.

According to the method of the present invention, preferably in step (2), the conditions of hydrothermal treatment include: pressure of 0-3MPa, time of 0.5-72h, and pressure of gauge pressure.

According to the method of the present invention, preferably in step (2), the mass ratio of the contacted product to the alkali source in terms of dry weight is (1-100):1.

According to a preferred embodiment of the present invention, step (2) is carried out in the presence of a precious metal source, preferably the mass ratio of the contacted product to the precious metal source in terms of dry weight is (20-1000): 1, preferably (20-50 ):1.

According to the method of the present invention, preferably, the source of precious metals is oxides of precious metals, halides of precious metals, carbonates of precious metals, nitrates of precious metals, ammonium nitrates of precious metals, ammonium chlorides of precious metals, and hydroxides of precious metals. One or more of complexes of compounds and precious metals, such as one or more of Ru, Rh, Pd, Re, Os, Ir, Pt, Ag and Au; preferably, the precious metals are Pd, Ag, Au and/or Pt, taking palladium as an example, the precious metal source is selected from palladium oxide, palladium carbonate, palladium chloride, palladium nitrate, palladium ammonium nitrate, palladium ammonia chloride, palladium acetate, palladium hydroxide, One or more of palladium complex, palladium acetate and palladium acetylacetonate.

According to the method of the present invention, the types of alkali sources can be selected in a wide range, and can be organic alkali sources and/or inorganic alkali sources, such as urea, ammonia, alkali metal compounds, alkaline earth metal compounds, quaternary amine base compounds, fats One or more of aliphatic amine compounds and aliphatic alcohol amine compounds.

In the present invention, the quaternary ammonium base can be various organic quaternary ammonium bases, and the aliphatic amine can be a compound formed after at least one hydrogen in various NH ₃ is replaced by an aliphatic hydrocarbon group (preferably an alkyl group). , the aliphatic alcohol amine may be a compound formed after at least one hydrogen in various NH ₃ is replaced by a hydroxyl-containing aliphatic hydrocarbon group (preferably an alkyl group).

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

In formula II, R ₅ , R ₆ , R ₇ and R ₈ are each a C ₁ -C ₄ alkyl group, including a C ₁ -C ₄ straight chain alkyl group and a C ₃ -C ₄ branched chain alkyl group, such as : R ₅ , R ₆ , R ₇ and R ₈ can each be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl.

R ⁹ (NH ₂ ) _n (Formula III)

In formula III, n is an integer of 1 or 2. When n is 1, R ⁹ is a C ₁ -C ₆ alkyl group, including a C ₁ -C ₆ straight chain alkyl group and a C ₃ -C ₆ branched chain alkyl group, such as methyl, ethyl, n-propyl , isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, isopentyl, tert-amyl and n-hexyl. When n is 2, R ⁹ is a C ₁ -C ₆ alkylene group, including a C ₁ -C ₆ straight chain alkylene group and a C ₃ -C ₆ branched chain alkylene group, such as methylene, ethylene , n-propylene, n-butylene, n-pentylene or n-hexylene.

(HOR ¹⁰ ) _m NH _(3-m) (Formula IV)

In formula IV, m R ^10s are the same or different, and each is a C ₁ -C ₄ alkylene group, including a C ₁ -C ₄ straight chain alkylene group and a C ₃ -C ₄ branched chain alkylene group, such as methylene, ethylene, n-propylene and n-butylene; m is 1, 2 or 3.

According to a preferred embodiment of the present invention, preferably the alkali source is ammonia water, sodium hydroxide, potassium hydroxide, calcium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, tetrapropylammonium hydroxide, tetraethyl hydroxide One of ammonium hydroxide, tetramethylammonium hydroxide, tetrabutylammonium hydroxide, ethylamine, n-propylamine, n-butylamine, di-n-propylamine, butanediamine, hexamethylenediamine, monoethanolamine, diethanolamine and triethanolamine or more. For example, the mixture of tetraethylammonium hydroxide and n-butylamine, the mixture of ethylenediamine and tetrapropylammonium hydroxide, the mixture of di-n-propylamine and tetrapropylammonium hydroxide, the mixture of tetraethylammonium hydroxide A mixture of ammonium and tetrapropylammonium hydroxide, and a mixture of hexamethylenediamine and tetrapropylammonium hydroxide can be used in the present invention, and there is no special requirement for the above mixing ratio.

According to the method of the present invention, preferably the method of the present invention further comprises: recovering a solid product from the product of the hydrothermal treatment, wherein the step of recovering the solid product generally includes: filtering, washing and other steps, which are well known to those skilled in the art, and in the This is not described in detail.

According to the method of the present invention, preferably the method further comprises: purging the hydrothermally treated solid product at 100-300° C. for 0.1-10 h in an inert atmosphere, wherein the inert atmosphere is a nitrogen atmosphere or an air atmosphere.

According to the method of the present invention, preferably the method further comprises: before performing step (1), contacting the unloading agent with a modification liquid containing nitric acid and at least one peroxide to carry out modification treatment, and in the modification In the chemical treatment, the molar ratio of the unloading agent as a raw material to the peroxide in terms of titanium silicon molecular sieve is 1:(0.01-5), preferably 1:(0.05-3), more preferably 1:(0.1 -2), the molar ratio of the peroxide to the nitric acid is 1:(0.01-50), preferably 1:(0.1-20), more preferably 1:(0.2-10), further preferably 1 : (0.5-5), particularly preferably 1: (0.6-3.5), the titanium-silicon molecular sieve is calculated as silicon dioxide.

According to the method of the present invention, preferably, in the modification solution, the concentration of the peroxide and nitric acid is 0.1-50% by weight, preferably 0.5-25% by weight, more preferably 5-15% by weight; wherein, The peroxide is selected from the group consisting of hydrogen peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, ethylbenzene hydroperoxide, cyclohexyl hydroperoxide, peroxyacetic acid and peroxypropionic acid.

According to the method of the present invention, preferably in the modification treatment, the unloading agent as a raw material and the modification liquid are heated at 10-350°C, preferably 20-300°C, more preferably 50-250°C, further preferably 60- The contact is carried out at a temperature of 200° C., the contact is carried out in a container with a pressure of 0-5 MPa, the pressure is gauge pressure, and the duration of the contact is 1-10 hours, preferably 3-5 hours.

The present invention provides the catalyst obtained by the method of the present invention.

The present invention provides the application of the catalyst of the present invention in oxidation reaction.

The present invention will be further illustrated by the following examples, but the content of the present invention is not limited accordingly.

In the comparative examples and examples, the reagents used are all commercially available chemically pure reagents.

The unloading agents of the following examples and comparative examples were obtained according to the following steps, and the following methods were used to determine the activity of titanium-silicon molecular sieves (including titanium-silicon molecular sieve unloading agents, and titanium-silicon molecular sieve fresh agents).

Take TS-1 molecular sieve (prepared by the method described in "Zeolites, 1992, Vol.12: 943-950", the mass percentage of TiO ₂ is 2.1%, the relative crystallinity is 100%) and placed in a 100 mL belt continuous In the slurry bed reactor of the feed and membrane separation device, a mixture of water and 30 wt% hydrogen peroxide was added at a rate of 5.7 mL/h under stirring (the volume ratio of water to hydrogen peroxide was 10:9), Add the mixture of cyclohexanone and tert-butanol at a speed of 10.5mL/h (the volume ratio of cyclohexanone and tert-butanol is 1:2.5), add 36wt% ammonia water at a speed of 5.7mL/h, the above three streams In order to add at the same time, continuously discharge material at the corresponding speed at the same time, the reaction temperature is maintained at 80 ° C, after the reaction is stable, the product is sampled every 1 hour to analyze the composition of the liquid phase by gas chromatography, and the following formula is used to calculate the cyclohexanone. conversion and use it as the activity of titanium-silicon molecular sieves. Conversion rate of cyclohexanone=[(molar amount of cyclohexanone added−molar amount of unreacted cyclohexanone)/molar amount of cyclohexanone added]×100%.

The conversion of cyclohexanone measured for the first time, i.e. 1 h, was 99.5% of its initial activity. After a period of about 168 hours, the conversion rate of cyclohexanone dropped from the initial 99.5% to 50%. After separating the catalyst, it was regenerated by calcination regeneration (calcined at 570 °C for 4 hours in an air atmosphere), and then continued to be used for In the ammoximation reaction of cyclohexanone, this step is repeated until the regenerated activity is lower than 50% of the initial activity. At this time, the deactivated ammoximation catalyst sample is used as the unloading agent of the present invention. The unloading agents SH-1 (activity is 50%, relative crystallinity is 87%), SH-2 (activity is 40%, relative crystallinity is 75%), SH-3 (activity is 25%, relative crystallinity is 75%) are obtained 68%), SH-4 (10% activity, 54% relative crystallinity).

Among them, the X-ray diffraction (XRD) crystal phase diagram of the unloading agent sample was measured on a Siemens D5005 X-ray diffractometer. The ratio of the sum of diffraction intensities (peak heights) represents the crystallinity of the sample relative to the reference sample. Here, the fresh agent sample is used as the reference sample, and its crystallinity is calculated as 100%, and the relative crystallinity of each unloading agent sample is calculated.

In the present invention, the specific surface area of the micropores is measured by the N ₂ constant temperature adsorption-desorption method.

Example 1

Under the condition of normal pressure of 90 ℃, DMSO and unloading agent (SH-1) were mixed and contacted for 5.5 hours, wherein the weight ratio of unloading agent and DMSO was 1:10, filtered, washed with water The contacted solid product was obtained, which was then dried to constant weight at 180°C;

The dried solid was mixed with the ammonia solution and then hydrothermally treated at pH 10 at 170 °C for 15 h, the mass ratio of solid to ammonia was 50:1, filtered, washed with water, dried (120 °C) to constant weight, and recovered to obtain molecular sieve A, Its activity, relative crystallinity and microporous specific surface area are shown in Table 1 (the method for measuring the activity is consistent with the method and steps for measuring the fresh agent, and the conversion rate of cyclohexanone measured in the first hour is used as the activity).

Example 2

Under normal pressure of 80°C, dimethyl sulfoxide and unloading agent (SH-2) were mixed and contacted for 7.5 hours, wherein the weight ratio of unloading agent and dimethyl sulfoxide was 1:5, filtered and washed with water. The solid product after contact is then dried to constant weight at 180°C;

Then, the dried solid was mixed with aqueous ammonia solution and then hydrothermally treated at pH 10 at 150 °C for 12 h, the mass ratio of solid to ammonia was 20:1, filtered, washed with water, dried (120 °C) to constant weight, and recovered to obtain molecular sieve B , its activity, relative crystallinity and microporous specific surface area are shown in Table 1.

Example 3

Under the condition of normal pressure 60 ℃, the N-methylpyrrolidone and the discharge agent (SH-3) were mixed and contacted for 15h, wherein the weight ratio of the discharge agent and N-methylpyrrolidone was 1:25, filtered and washed with water to obtain The solid product after contact is then dried to constant weight at 180°C;

The dried solid was mixed with an aqueous diethanolamine solution and then hydrothermally treated at pH 11 at 150 °C for 6 h, the mass ratio of solid to diethanolamine was 80:1, filtered, washed with water, and dried (120 °C) to constant weight to obtain molecular sieve C. , its activity, relative crystallinity and microporous specific surface area are shown in Table 1 (the activity measurement method is consistent with the method and steps for measuring the fresh agent, and the cyclohexanone conversion rate measured in the first hour is used as the activity).

Example 4

Under the condition of normal pressure of 90 ℃, N,N-dimethylformamide, liquid ammonia and discharge agent (SH-4) were mixed and contacted for 2.5h, wherein the discharge agent and N,N-dimethylformamide The weight ratio of liquid ammonia and N,N-dimethylformamide is 1:15, the mass ratio of liquid ammonia and N,N-dimethylformamide is 0.005:1, filtered and washed to obtain the solid product after the contact, and then dried to constant weight at 180 ° C;

The dried solid was mixed with the mixed aqueous solution of hexamethylene diamine and tetrapropyl ammonium hydroxide, and then hydrothermally treated at pH 13 and 150 ° C for 0.5 h, and the mass ratio of solid, hexamethylene diamine and tetrapropyl ammonium hydroxide was 100. : 10:10, the obtained solid product was dried at 200°C for 3h in an air atmosphere to obtain molecular sieve D, and its activity, relative crystallinity and micropore specific surface area are shown in Table 1 (the method for measuring the activity is consistent with the method and steps for measuring the fresh agent) , and the cyclohexanone conversion rate measured in the first h was used as the activity).

Example 5

The catalyst was prepared according to the method of Example 1, and molecular sieve E was obtained. The difference was that before contacting with the organic compound, the discharge agent was modified as follows, and the remaining steps were the same:

The discharge agent (SH-1) was mixed with an aqueous solution containing HNO ₃ (the mass concentration of HNO ₃ was 10%) and hydrogen peroxide (the mass concentration of hydrogen peroxide was 7.5%), and the resulting mixture was placed in a closed container The reaction was stirred at 70 °C for 5 h, the temperature of the obtained reaction mixture was lowered to room temperature, and then filtered, and the obtained solid phase substance was dried at 120 °C to constant weight to obtain a modified discharge agent. Wherein, the discharge agent is calculated as SiO ₂ , and the molar ratio of the discharge agent to hydrogen peroxide is 1:0.1.

Example 6

The catalyst was prepared according to the method of Example 2, and the molecular sieve F was obtained. The difference was that before contacting with the organic compound, the discharge agent was modified as follows:

The discharge agent (SH-2) was mixed with an aqueous solution containing _HNO3 (10% by mass of _HNO3 ) and hydrogen peroxide (5% by mass of hydrogen peroxide), and the resulting mixture was placed in a closed container The reaction was stirred at 120 °C for 4 h, the temperature of the obtained reaction mixture was lowered to room temperature, and then filtered, and the obtained solid phase substance was dried at 120 °C to constant weight to obtain a modified discharge agent. Wherein, the unloading agent is calculated as SiO ₂ , and the molar ratio of the unloading agent and hydrogen peroxide is 1:0.4.

Example 7

The catalyst was prepared according to the method of Example 3, and molecular sieve G was obtained. The difference was that before contacting with the organic compound, the discharge agent was modified as follows:

The discharge agent (SH-3) was mixed with an aqueous solution containing HNO ₃ (the mass concentration of HNO ₃ was 15%) and hydrogen peroxide (the mass concentration of hydrogen peroxide was 8%), and the resulting mixture was placed in a closed container The reaction was stirred at 150 °C for 3 h, the temperature of the obtained reaction mixture was lowered to room temperature, and then filtered, and the obtained solid phase substance was dried at 120 °C to constant weight to obtain a modified discharge agent. Wherein, the unloading agent is calculated as SiO ₂ , and the molar ratio of the unloading agent and hydrogen peroxide is 1:2.

Example 8

The catalyst is prepared according to the method of Example 4, except that the contact between the organic compound and the discharge agent is not carried out in the presence of ammonia, as follows:

Under the condition of normal pressure of 90 ℃, N,N-dimethylformamide and discharge agent (SH-4) were mixed and contacted for 15h, wherein the weight ratio of discharge agent to N,N-dimethylformamide was 1:15, filtered and washed with water to obtain the solid product after contact, and then dried to constant weight at 180°C;

The dried solid was mixed with the mixed aqueous solution of hexamethylene diamine and tetrapropyl ammonium hydroxide, and then hydrothermally treated at pH 13 and 150 ° C for 0.5 h, and the mass ratio of solid, hexamethylene diamine and tetrapropyl ammonium hydroxide was 100. : 10:10, the obtained solid product was dried at 200°C for 3h in an air atmosphere to obtain molecular sieve H, and its activity, relative crystallinity and micropore specific surface area are shown in Table 1 (the method for measuring the activity is consistent with the method and steps for measuring the fresh agent). , and the cyclohexanone conversion rate measured in the first h was used as the activity).

Example 9

The catalyst is prepared according to the method of Example 4, except that step (2) is carried out in the presence of a precious metal source, as follows:

Under the condition of normal pressure of 90 ℃, N,N-dimethylformamide, liquid ammonia and discharge agent (SH-4) were mixed and contacted for 2.5h, wherein the discharge agent and N,N-dimethylformamide The weight ratio of liquid ammonia and N,N-dimethylformamide is 1:15, the mass ratio of liquid ammonia and N,N-dimethylformamide is 0.005:1, filtered and washed to obtain the solid product after the contact, and then dried to constant weight at 180 ° C;

The dried solid, palladium chloride and the mixed aqueous solution of hexamethylenediamine and tetrapropylammonium hydroxide were mixed and then hydrothermally treated at pH 13 at 150 °C for 0.5h, and the solid, hexamethylenediamine and tetrapropylammonium hydroxide were mixed with water for 0.5 h. The mass ratio is 100:10:10, the mass ratio of the solid to palladium chloride is 100:5, and the obtained solid product is dried in an air atmosphere at 200 ° C for 3h to obtain molecular sieve I, its activity, relative crystallinity and micropore ratio The surface area is shown in Table 1 (the method for measuring the activity is consistent with the method and steps for measuring the fresh agent, and the conversion rate of cyclohexanone measured in the first hour is used as the activity).

Example 10

The catalyst is prepared according to the method of Example 4, except that step (2) is carried out in the presence of a precious metal source, as follows:

Under the condition of normal pressure of 90 ℃, N,N-dimethylformamide, liquid ammonia and discharge agent (SH-4) were mixed and contacted for 2.5h, wherein the discharge agent and N,N-dimethylformamide The weight ratio of liquid ammonia and N,N-dimethylformamide is 1:15, the mass ratio of liquid ammonia and N,N-dimethylformamide is 0.005:1, filtered and washed to obtain the solid product after contact, and then dried to constant weight at 150 ° C;

After mixing the dried solid, platinum nitrate and the mixed aqueous solution of hexamethylene diamine and tetrapropyl ammonium hydroxide, the pH is 13, 150 ℃ hydrothermal treatment for 0.5h, the quality of solid, hexamethylene diamine and tetrapropyl ammonium hydroxide The ratio is 100:5:25, and the mass ratio of solid to platinum nitrate is 100:5. The obtained solid product is dried at 200 °C for 3 hours in an air atmosphere to obtain molecular sieve J. Its activity, relative crystallinity and micropore specific surface area are shown in Table 1 (the method for measuring the activity is consistent with the method and steps for measuring the fresh agent, and the conversion rate of cyclohexanone measured in the first h is used as the activity).

Example 11

The catalyst is prepared according to the method of embodiment 4, the main difference is that step (2) is carried out in the presence of a precious metal source, as follows:

Under the condition of normal pressure of 90 ℃, N,N-dimethylformamide, liquid ammonia and discharge agent (SH-4) were mixed and contacted for 2.5h, wherein the discharge agent and N,N-dimethylformamide The weight ratio of liquid ammonia and N,N-dimethylformamide is 1:15, the mass ratio of liquid ammonia and N,N-dimethylformamide is 0.005:1, filtered and washed to obtain the solid product after contact, and then dried to constant weight at 150 ° C;

After mixing the dried solid, palladium acetate with the mixed aqueous solution of hexamethylene diamine and tetrapropyl ammonium hydroxide, the pH is 14, 170 ℃ hydrothermal treatment for 0.5h, the quality of solid, hexamethylene diamine and tetrapropyl ammonium hydroxide The ratio is 100:15:25, and the mass ratio of solid to platinum nitrate is 100:2. The obtained solid product is dried at 200 °C for 3 hours in an air atmosphere to obtain molecular sieve K. Its activity, relative crystallinity and micropore specific surface area are shown in Table 1 (the method for measuring the activity is consistent with the method and steps for measuring the fresh agent, and the conversion rate of cyclohexanone measured in the first h is used as the activity).

Table 1

Example sample active,% Relative crystallinity, % Micropore specific surface area, m²/g 1 A 94.5 96 361 2 B 95.3 98 353 3 C 95.6 99 368 4 D 96.5 100 361 5 E 97.2 99 378 6 F 98.3 99 380 7 G 98.9 100 385 8 H 94.5 97 358 9 I 99.9 100 381 10 J 99.8 99 382 11 K 99.5 100 379 freshener 99.5 100 376

As can be seen from the data in Table 1, the titanium-containing silicon molecular sieve catalyst obtained by the preparation method provided by the present invention has superior catalytic performance compared with the prior art calcination or the method of pickling and calcination, and the crystallinity and microscopic The pore specific surface area was basically completely recovered. In particular, introducing a small amount of ammonia when contacting with organic compounds can further improve the effect of the prepared catalyst, and can greatly shorten the contact time.

It can be seen from the results of the method of the present invention that the present invention does not need to regenerate at high temperature, the activity, crystallinity and micropore specific surface area of the prepared catalyst can be basically completely recovered, energy consumption is effectively saved, and it is very suitable for industrial application.

The preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the specific details of the above-mentioned embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention. These simple modifications All belong to the protection scope of the present invention.

In addition, it should be noted that each specific technical feature described in the above-mentioned specific implementation manner may be combined in any suitable manner under the circumstance that there is no contradiction. In order to avoid unnecessary repetition, the present invention will not describe various possible combinations.

In addition, the various embodiments of the present invention can also be combined arbitrarily, as long as they do not violate the spirit of the present invention, they should also be regarded as the contents disclosed in the present invention.

Claims (25)

1. a preparation method of a titanium-silicon molecular sieve catalyst, is characterized in that, the method comprises: (1) contacting an unloading agent with an organic compound to obtain a contacted product, the organic compound is selected from one or more of sulfones, ketones and amides, and the unloading agent is a catalyst active group using titanium-silicon molecular sieves The discharge agent of the separate reaction device; (2) in the presence of a water-containing solvent, hydrothermal treatment is carried out after mixing the contacted product with the alkali source; In step (1), the contact is carried out in the presence of ammonia, and the mass ratio of ammonia to the organic compound is (0.0001-0.1): 1; In step (2), the hydrothermal treatment conditions include: pH value is 8-14, temperature is 120-200°C, pressure is 0-3MPa, time is 0.5-72h, and pressure is gauge pressure; The step (2) is carried out in the presence of a precious metal source, and the mass ratio of the contacted product to the precious metal source is (20-1000):1 in terms of dry weight. 2. The preparation method according to claim 1, wherein the organic compound is dimethyl sulfoxide, sulfolane, N-methylpyrrolidone, N,N-dimethylformamide and N,N-dimethylformamide One or more of acetamides. 3 . The preparation method according to claim 1 , wherein the unloading agent of the reaction device using titanium-silicon molecular sieve as the catalyst active component is the unloading agent of the ammoximation reaction device. 4 . 4 . The preparation method according to claim 1 , wherein the titanium-silicon molecular sieve has an MFI structure, and the activity of the unloading agent is 50% or less of the activity when fresh. 5 . 5. The preparation method according to any one of claims 1-4, wherein, in step (1), the contacting temperature is lower than the boiling point of the organic compound. 6. The preparation method according to any one of claims 1-4, wherein the contacting temperature is 20-250°C lower than the boiling point of the organic compound. 7. The preparation method according to any one of claims 1-4, wherein, in step (1), the mass ratio of the organic compound to the unloading agent is (0.5-100):1. 8. The preparation method according to any one of claims 1-4, wherein, in step (2), The mass ratio of the contacted product to the alkali source in terms of dry weight is (1-100): 1, The alkali source is ammonia water, sodium hydroxide, potassium hydroxide, calcium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, tetrapropylammonium hydroxide, tetraethylammonium hydroxide, tetramethylammonium hydroxide, One or more of tetrabutylammonium hydroxide, ethylamine, n-propylamine, n-butylamine, di-n-propylamine, butanediamine, hexamethylenediamine, monoethanolamine, diethanolamine and triethanolamine. 9. The preparation method according to any one of claims 1-4, wherein the precious metal source is oxides of precious metals, halides of precious metals, carbonates of precious metals, nitrates of precious metals, and hydroxides of precious metals One or more of a complex compound of a compound and a noble metal, the noble metal being one or more of Ru, Rh, Pd, Os, Ir, Pt, Ag and Au. 10 . The preparation method according to claim 1 , wherein the method further comprises: purging the hydrothermally treated solid product at 100-300° C. for 0.1-10 h in a nitrogen atmosphere or an air atmosphere. 11 . 11. The preparation method according to any one of claims 1-4, wherein the method further comprises: before carrying out step (1), mixing the unloading agent with a solution containing nitric acid and at least one peroxide. The modification liquid is contacted to carry out modification treatment. In the modification treatment, the molar ratio of the unloading agent as a raw material to the peroxide is 1:(0.01-5) in terms of titanium silicon molecular sieve, and the peroxide is The molar ratio of the compound to the nitric acid is 1:(0.01-50), and the titanium silicon molecular sieve is calculated as silicon dioxide. 12. The preparation method according to claim 11, wherein, in the modification treatment, the molar ratio of the unloading agent as a raw material to the peroxide in terms of titanium silicon molecular sieve is 1:(0.05-3) , the molar ratio of the peroxide to the nitric acid is 1:(0.1-20), and the titanium silicon molecular sieve is calculated as silicon dioxide. 13. The preparation method according to claim 11, wherein, in the modification treatment, the molar ratio of the unloading agent as a raw material to the peroxide in terms of titanium silicon molecular sieve is 1:(0.1-2) , the molar ratio of the peroxide to the nitric acid is 1:(0.2-10), and the titanium silicon molecular sieve is calculated as silicon dioxide. The preparation method according to claim 11, wherein, in the modification treatment, the molar ratio of the peroxide to the nitric acid is 1:(0.5-5). The preparation method according to claim 11, wherein, in the modification treatment, the molar ratio of the peroxide to the nitric acid is 1:(0.6-3.5). 16. The preparation method according to claim 11, wherein, in the modified liquid, the concentration of the peroxide and nitric acid is each 0.1-50 wt%; wherein, the peroxide is selected from hydrogen peroxide , one or more of tert-butyl hydroperoxide, cumene hydroperoxide, ethylbenzene hydroperoxide, cyclohexyl hydroperoxide, peroxyacetic acid and peroxypropionic acid. 17 . The preparation method according to claim 11 , wherein, in the modification liquid, the concentration of the peroxide and the nitric acid is each 0.5-25 wt %. 18 . 18. The preparation method according to claim 11, wherein, in the modification liquid, the concentration of the peroxide and the nitric acid is 5-15% by weight, respectively. 19 . The production method according to claim 11 , wherein, in the modification treatment, a discharge agent as a raw material is contacted with the modification liquid at a temperature of 10-350° C., and the contact is carried out under pressure. 20 . It is carried out in a container of 0-5MPa, the pressure is gauge pressure, and the duration of the contact is 1-10 hours. 20 . The production method according to claim 11 , wherein, in the modification treatment, a discharge agent as a raw material is brought into contact with the modification liquid at a temperature of 20-300° C. 21 . 21 . The production method according to claim 11 , wherein, in the modification treatment, a discharge agent as a raw material is brought into contact with the modification liquid at a temperature of 50-250° C. 21 . 22 . The production method according to claim 11 , wherein, in the modification treatment, a discharge agent serving as a raw material is brought into contact with the modification liquid at a temperature of 60-200° C. 23 . 23. The preparation method according to claim 11, wherein, in the modification treatment, the duration of the contact is 3-5 hours. 24. The catalyst prepared by the method of any one of claims 1-23. 25. Use of the catalyst of claim 24 in oxidation reactions.