CN114425438B - Preparation method of titanium-containing catalyst, titanium-containing catalyst and method for preparing epoxy compound - Google Patents

Abstract

A preparation method for a titanium-containing catalyst, characterized in that the method comprises the following steps: (1) mixing an amorphous silicon source, a titanium source, and an alkaline aqueous solution and heat-treating to prepare silicon-titanium colloid, and then mixing with titanium-silicon molecular sieves and auxiliary agents , ammonium salt mixed and molded to obtain a shaped catalyst; (2) the shaped catalyst is treated for 0.5-3h under the conditions of external pressure and external addition of water, an apparent pressure of 0.01-1.0MPa, and a temperature of 100-300°C; (3) the (2) Treat the shaped catalyst obtained by adding a liquid with a pH value > 9 for at least 0.5 h at a superficial pressure of 0.01-1.0 MPa and a temperature of 300-600° C. to obtain a titanium-containing catalyst. The operation process of the invention is simple, and the titanium-silicon molecular sieve crystal grains containing the titanium catalyst have numerous mesopores of 4-20 nm in size, and have excellent catalytic performance in the olefin epoxidation reaction.

Description

A kind of preparation method of titanium-containing catalyst, titanium-containing catalyst and preparation of epoxy synthesis way of things

technical field

The invention relates to a preparation method of a catalyst, a catalyst and an application thereof, more specifically, the invention relates to a preparation method of a titanium-containing catalyst, a titanium-containing catalyst and a method for preparing epoxy compounds.

Background technique

Due to their active epoxy bonds, epoxy compounds can be used to prepare a variety of important chemicals, which are closely related to people's daily life, so they play an important role. Among them, propylene oxide is mainly used to produce chemicals such as polyurethane and propylene glycol, and the domestic production capacity has reached 3 million tons per year. Using titanium-silicon molecular sieves to catalyze the one-step reaction of propylene-hydrogen peroxide to prepare propylene oxide is popular because of the few reaction steps and clean production process. Among them, the highly active titanium-containing catalyst is the research focus of propylene epoxidation to prepare propylene oxide.

The preparation of highly active titanium-containing catalysts involves two main aspects of work, one is the preparation of highly active titanium-silicon molecular sieves, and the other is the preparation of high-performance shaped catalysts. CN1301599A discloses a titanium-silicon molecular sieve with an intracrystalline hollow structure, which has excellent performance in olefin epoxidation due to its unique structure. CN101274922A further discloses a propylene epoxidation reaction using the titanium-silicon molecular sieve raw powder described in CN1301599A as a catalyst, and using the formed titanium-containing catalyst. Using the original powder for the reaction will bring engineering problems to the separation of the product and the catalyst, and the forming method described in this method has a titanium-silicon molecular sieve content of only 70%, and a selectivity of propylene oxide of 72.5%, and the catalytic performance needs to be further improved.

CN102441430A discloses a method for forming a titanium-containing catalyst obtained by molding the hollow titanium-silicon molecular sieve described in CN1132699C by using amorphous silica as a binder. The hydrogen peroxide conversion rate of the catalyst obtained by the method can reach 96.7%. The selectivity of propylene oxide can reach 95.0%.

Overall, from the preparation of titanium-silicon molecular sieves to the molding of titanium-containing catalysts, due to the complex preparation methods of high-performance titanium-silicon molecular sieves, the overall energy consumption and material consumption of titanium-containing catalysts are relatively high, and the economy is low. How to shorten the preparation process of titanium-containing catalysts for olefin epoxidation and simultaneously prepare high-performance epoxidation catalysts is an urgent problem to be solved.

Contents of the invention

One of the objectives of the present invention is to provide a preparation method of a titanium-containing catalyst, the titanium-containing catalyst has a large number of mesopores of 4-20 nm in the titanium-silicon molecular sieve grain, and has good olefin epoxidation catalytic performance. Compared with the existing preparation method, the method has a simpler preparation process, can effectively utilize the template agent in the molecular sieve crystal, and simultaneously generate small-sized mesopores in the molecular sieve crystal to improve the catalytic performance.

The second object of the present invention is to provide a titanium-containing catalyst prepared by the method of the present invention.

The third object of the present invention is to provide the application of the molecular sieve.

In order to realize one of the purposes of the present invention, the present invention provides a kind of preparation method of titanium-containing catalyst, it is characterized in that, this method comprises the following steps:

(1) Mix and heat-treat amorphous silicon source, titanium source, and alkaline aqueous solution to prepare silicon-titanium gel, and then mix it with titanium-silicon molecular sieve, additives, and ammonium salt to obtain a molding catalyst;

(2) Treat the shaped catalyst for 0.5-3h under the conditions of external pressure and external addition of water, apparent pressure of 0.01-1.0MPa, and temperature of 100-300°C;

(3) Treat the molded catalyst obtained in (2) with a superficial pressure of 0.01-1.0 MPa and a temperature of 300-600° C. for at least 0.5 h to obtain a titanium-containing catalyst.

In order to achieve the second objective of the present invention, the present invention provides a titanium-containing catalyst prepared according to the method of the present invention.

In order to achieve the third objective of the present invention, the present invention provides the application of the titanium-containing catalyst in the catalytic reaction of olefin epoxidation.

The preparation method of the titanium-containing catalyst provided by the invention has the advantages of simple process, easy implementation and good effect, and can effectively utilize the molecular sieve intracrystalline template agent to produce a small-sized mesoporous structure. The titanium-containing catalyst provided by the invention has a good effect in the catalytic oxidation reaction of olefin epoxidation, and when it is used for the epoxidation of propylene to prepare propylene oxide, it has high catalytic activity, high conversion rate of hydrogen peroxide, and high selectivity of propylene oxide. The effective utilization rate of hydrogen peroxide is high.

Description of drawings

FIG. 1 is a TEM image of the titanium-silicon molecular sieve obtained in Comparative Example 1.

2 is a TEM image of the titanium-silicon molecular sieve in the titanium-containing catalyst obtained in Example 1.

Detailed ways

The present invention provides a kind of preparation method of titanium-containing catalyst, it is characterized in that, the method comprises the following steps:

(1) Mix and heat-treat amorphous silicon source, titanium source, and alkaline aqueous solution to prepare silicon-titanium gel, and then mix it with titanium-silicon molecular sieve, additives, and ammonium salt to obtain a molding catalyst;

(2) Treat the shaped catalyst for 0.5-3h under the conditions of external pressure and external addition of water, apparent pressure of 0.01-1.0MPa, and temperature of 100-300°C;

(3) Treat the molded catalyst obtained in (2) with a superficial pressure of 0.01-1.0 MPa and a temperature of 300-600° C. for at least 0.5 h to obtain a titanium-containing catalyst. .

In the method of the present invention, the titanium-silicon molecular sieve described in step (1) can have AEL, AFI, AFN, BEC, CFI, CHA, CON, EUO, FAU, FER, IMF, LTA, MER, MFI, MEL, MOR, MWW, RHO, TON, *BEA, *EWT, two-dimensional hexagonal phase structure, among which MFI structure is preferable.

In the method of the present invention, the titanium-silicon molecular sieve described in step (1) can be a titanium-silicon molecular sieve that does not contain organic matter through roasting, or a titanium-silicon molecular sieve that contains organic matter such as a template, preferably a titanium-silicon molecular sieve that contains a template. The titanium-silicon molecular sieve containing the template includes the titanium-silicon molecular sieve prepared by hydrothermal synthesis or rearrangement, filtered and dried but not roasted to remove the template. In the titanium-silicon molecular sieve containing a template agent, the content of the template agent preferably accounts for 1-30% by weight of the molecular sieve.

The template includes organic amine compounds, such as aliphatic amines, aromatic amines, alcohol amines, organic quaternary ammonium bases, organic quaternary ammonium salts and/or long-chain alkyl ammonium compounds.

The organic amine can be one or more of aliphatic amines, aromatic amines and alcohol amines. The general formula of the aliphatic amines (or fatty amine compounds) is written as R ¹ (NH ₂ ) _n , wherein R ¹ is an alkyl or alkylene group having 1 to 8 carbon atoms, n=1 or 2; the general formula of the alcohol amine (or alcohol amine compound) is written as (HOR ² ) _m NH _{( 3-m)} , wherein R ² is a normal or isoalkyl group with 1 to 8 carbon atoms, m=1, 2 or 3. The fatty amines include one or more of ethylamine, n-propylamine, n-butylamine, butylenediamine, hexamethylenediamine, cyclopentylamine and cyclohexylamine. The aromatic amine refers to an amine having an aromatic substituent, such as one or more of aniline, amphetamine, p-phenylenediamine, and toluidine. The alcohol amine may be, for example, one or more of monoethanolamine, diethanolamine, and triethanolamine.

Described organic quaternary ammonium base comprises one or more selected from such as tetrapropyl ammonium hydroxide, tetrabutyl ammonium hydroxide or tetraethyl ammonium hydroxide; Described organic quaternary ammonium salt comprises selected from such as tetrapropyl ammonium hydroxide One or more of alkyl ammonium bromide, tetrabutyl ammonium bromide, tetraethyl ammonium bromide, tetrapropyl ammonium chloride, tetrabutyl ammonium chloride or tetraethyl ammonium chloride.

The general formula of the long-chain alkyl ammonium compound is written as R ³ NH ₃ X or R ³ N(R ⁴ ) ₃ X, wherein R ³ represents normal or isoparaffin with 12-18 carbon atoms R ⁴ represents a normal or isomeric alkyl group with 1 to 4 carbon atoms; X represents a monovalent anion, such as OH ^- , Cl ^- , Br ^- ; when X is OH ^- , the present invention It is called a basic long-chain alkyl ammonium compound; the long-chain alkyl ammonium compound can include octadecyltrimethylammonium hydroxide, octadecyltrimethylammonium bromide, octadecyltrimethylammonium bromide, octadecyltrimethylammonium Ammonium Chloride, Cetyl Trimethyl Ammonium Bromide, Cetyl Trimethyl Ammonium Hydroxide, Cetyl Ammonium Chloride, Tetradecyl Trimethyl Ammonium Bromide, Myristyl Chloride One or more of ammonium chloride, tetradecyltrimethylammonium hydroxide, dodecyltrimethylammonium hydroxide, dodecyltrimethylammonium bromide, dodecylammonium chloride .

In the method of the present invention, the amorphous silicon source in step (1) includes silica sol and organosilicon ester. Silica sol includes acidic silica sol and alkaline silica sol, and the content of said silica sol is preferably 5%-40% by weight of silica. The organosilicon esters include organosilicon compounds with alkoxy groups, including tetraethyl silicate, tetrapropyl silicate, tetrabutyl silicate, trimethoxychlorosilane, triethoxyphenylsilane, One or more of triethoxypropenylsilane. The amorphous silicon source is preferably organosilicon ester, more preferably tetraethyl silicate.

In the method of the present invention, the titanium source described in step (1) includes organic titanium esters, titanium tetrachloride, titanium trichloride, titanium sulfate, preferably organic titanium esters, more preferably tetraethyl titanate, tetraisopropyl titanate One or more of esters and tetrabutyl titanate.

In the method of the present invention, the alkaline aqueous solution described in step (1) can be an aqueous solution containing an organic base or an inorganic base with a pH value of 10-14, and the organic base or inorganic base refers to a compound that is alkaline in water, Including organic amine compounds, such as aliphatic amines, aromatic amines, alcohol amines, organic quaternary ammonium bases, basic inorganic substances, such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, potassium phosphate , disodium hydrogen phosphate, dipotassium hydrogen phosphate, ammonia water or one or more. Organic quaternary ammonium base and ammonia water are preferred. More preferably one or more of tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, and ammonia water.

In the method of the present invention, the auxiliary agent described in step (1) includes one or more of squash powder, starch, polyols, and nanocellulose, and the preferred carbon number of the polyols is C2-C6 and has at least Compounds with two hydroxyl groups include, for example, ethylene glycol, propylene glycol, glycerin, glyceraldehyde, pentaerythritol, pentanediol, hexanediol, dihydroxyacetone, fructose, glucose, and the like.

In the method of the present invention, the ammonium salt described in step (1) is organic ammonium salt or inorganic ammonium salt, including ammonium acetate, ammonium chloride, ammonium carbonate, ammonium bicarbonate, ammonium nitrate, ammonium sulfate, ammonium bisulfate, ammonium phosphate , one or more of ammonium monohydrogen phosphate, ammonium dihydrogen phosphate, ammonium fluoride, and ammonium fluorosilicate, preferably one or more of ammonium acetate, ammonium carbonate, ammonium phosphate, and ammonium fluoride.

In the method of the present invention, the heat treatment in step (1) includes treatment at 50-100°C for 0.5-5h.

In the method of the present invention, the silica-titanium gel molar composition described in step (1): amorphous silicon source (calculated as silicon dioxide), titanium source (calculated as titanium dioxide), and water are 1: (0.05-0.30): (3 -10), preferably 1: (0.1-0.25): (4-8). The titanium-silicon molecular sieve, silica-titanium colloid, auxiliary agent and ammonium salt are preferably 100:(3-20):(1-6):(0.1-2), more preferably 100:(5-15 ):(1-4):(0.5-1.5).

In the method of the present invention, the molding described in step (1) includes rolling ball molding, extrusion molding after kneading. Titanium-containing catalysts formed by rolling ball molding and extrusion molding are more suitable for applications in fixed-bed reactors. The preparation method of the titanium-containing catalyst of the present invention can obtain the titanium-containing catalyst formed by ball rolling or extrusion with better performance.

In the method of the present invention, in step (2), the apparent pressure is preferably 0.1-0.6MPa, more preferably 0.2-0.4MPa, the treatment temperature is preferably 150-200°C, and the treatment time is preferably 1-2h. In step (3), the apparent pressure is preferably 0.2-0.7MPa, more preferably 0.3-0.5MPa, the treatment temperature is preferably 400-550°C, and the treatment time is preferably 3-6h. The two-step treatment of steps (2) and (3) is preferably carried out continuously by changing the temperature and switching materials.

In the method of the present invention, in step (3), the liquid with a pH value>9 is preferably ammonia water or an aqueous solution of organic amines. The mass fraction of alkaline substances in the liquid is preferably 1%-28%, more preferably 5%-20%. Described organic amine is preferably organic quaternary ammonium base and/or aliphatic amine, and described organic quaternary ammonium base can comprise a kind of in tetrapropyl ammonium hydroxide, tetraethyl ammonium hydroxide or tetrabutyl ammonium hydroxide or Various, the fatty amine (or called fatty amine compound), its general formula is written as R ¹ (NH ₂ ) _n , wherein R ¹ represents an alkyl or alkylene group with 1 to 8 carbon atoms, n =1 or 2, for example, it can be one or more of ethylamine, n-propylamine, n-butylamine, butylenediamine, hexamethylenediamine, cyclopentylamine, and cyclohexylamine. The liquid with a pH value>9 is further preferably ammonia water.

In the method of the present invention, steps (2) and (3) include making water and a liquid with a pH value>9 contact with the shaped catalyst at the temperature and pressure respectively, or make the liquid vaporize and then contact the shaped catalyst touch. Preferably, the method includes heating and vaporizing the water and the liquid with a pH value > 9, and making the generated gas contact with the shaped catalyst. Said contact includes static contact and fluid contact through titanium silicon molecular sieve. Described step (2) is preferably (0.1-2) g water/(g catalyst min) to the consumption of described water, is more preferably (0.3-0.8) g water/(g catalyst min); Step ( 3) The dosage of the liquid with pH>9 is preferably (0.1-2) g liquid/(g catalyst·min), more preferably (0.6-1.4) g liquid/(g catalyst·min)

Through the preparation method of the present invention, the titanium-containing catalyst can partially or completely remove the titanium-silicon molecular sieve template, and can no longer be roasted, and the titanium-containing catalyst after the above steps (2) and (3) can be further processed in the titanium-containing catalyst containing Calcination is carried out under an oxygen atmosphere. It may be that the titanium-containing catalyst treated in steps (2) and (3) is washed and/or dried and then calcined. The calcination can be carried out under oxygen-enriched or oxygen-poor conditions, the calcination temperature is preferably 300-800°C, and the calcination time is preferably 0.5-12h.

In order to maintain the high catalytic performance of the titanium-containing catalyst, the preparation method of the present invention may further include alkali washing the titanium-containing catalyst prepared by the above method with an ammonia solution and acid washing with an acid solution containing hydrogen peroxide. The pH value of the ammonia solution is preferably 9-14, more preferably 10-12, the weight percentage of the titanium-containing catalyst in the ammonia solution is preferably 1%-10%, more preferably 3%-7%, and the alkali Washing is preferably at 40-90°C for 10-120min, more preferably at 60-80°C for 30-90min. The pH value of the acid solution containing hydrogen peroxide is preferably 1-6, more preferably 2-4, and the weight percentage of hydrogen peroxide is preferably 0-5%, more preferably 0.3-3%. In the alkali washing, the weight percentage of the titanium-containing catalyst in the ammonia solution is preferably 1%-10%, more preferably 3%-7%. The pickling is preferably performed at 40-90°C for 10-120 minutes, more preferably at 60-80°C for 30-90 minutes.

The preparation method provided by the present invention can make full use of the template agent in the molecular sieve crystal to expand the pores in the crystal. The titanium-containing catalyst can be seen through TEM characterization that there are many 4-20nm particles in the titanium-silicon molecular sieve crystal grain of the titanium-containing catalyst. Mesoporous, the small-sized mesoporous structure is conducive to improving its catalytic performance.

The present invention also provides a titanium-containing catalyst, which is characterized in that it is prepared by the above preparation method. The titanium-containing catalyst can be further mixed with other catalysts, cocatalysts, structural aids, electronic aids, binders, inert carriers, etc. by mechanical mixing, kneading molding, tablet molding, extrusion molding, spray molding, ball rolling, etc. The catalytic mixture containing the above-mentioned titanium-containing catalyst is prepared by molding, oil column molding and other methods, and the percentage of the titanium-containing catalyst in the weight of the catalytic mixture is preferably greater than 10%.

The present invention further provides the application of the above-mentioned titanium-containing catalyst in the preparation of epoxy compounds by epoxidation of olefins, that is, a method for preparing epoxy compounds by epoxidation of olefins, characterized in that, under the conditions of the epoxidation reaction, in In the presence of a titanium-containing catalyst, olefins, hydrogen peroxide and a solvent are contacted to obtain a product containing an epoxy compound.

The epoxidation reaction conditions include, hydrogen peroxide: olefin: solvent molar ratio is preferably 1: (0.5-10): (2-30), more preferably 1: (2-5): (5-15), the reaction The temperature is preferably 10-80°C, more preferably 30-50°C, the reaction pressure is preferably 0.1-5MPa gauge pressure, and the hourly space velocity of the reaction solution is preferably 0.1-8h-1. The said solvent is preferably water or an alcohol, ester, or nitrile with 1-6 carbon atoms. Preferably, the olefin is propylene, that is, propylene oxide is prepared by epoxidation of propylene.

The application provided by the present invention can be carried out in various reactors such as tank reactor, slurry bed reactor, fixed bed reactor, fluidized bed reactor, moving bed reactor, microchannel reactor; Described reaction Raw materials and titanium-containing catalysts can be fed at one time, intermittently, or continuously; the separation of products and catalysts can be achieved in various ways, for example, the separation of products can be achieved by sedimentation, filtration, centrifugation, evaporation, membrane separation, etc. and catalyst recycling.

The present invention will be further described below by way of examples, but content of the present invention is not limited thereto.

In each of the following examples and comparative examples:

The content of the template agent in the molecular sieve is measured by thermogravimetric method, and the weight loss when the weight loss curve is above 200°C until the weight loss curve is stable is the template agent content of the molecular sieve.

The high-resolution morphology analysis of molecular sieves was characterized by TEM method.

Unless otherwise specified, the raw materials used in the examples and comparative examples are analytical reagents.

The amount of hydrogen peroxide was titrated by sodium thiosulfate method. The composition of the reaction product was analyzed by gas chromatography, and the analysis results were quantified by the external standard method. Among them, the chromatographic analysis conditions are: Agilent-6890 chromatograph, HP-5 capillary chromatographic column, injection volume 0.5 μL, inlet temperature 280°C. The column temperature was kept at 100°C for 2min, then increased to 250°C at a rate of 15°C/min, and kept for 10min. FID detector, detector temperature 300°C.

In embodiment and comparative example:

Conversion rate of hydrogen peroxide (%)=(mole number of hydrogen peroxide in the raw material-mole number of hydrogen peroxide in the product)/mole number of hydrogen peroxide in the raw material×100%

Epoxy compound selectivity (%) = the number of moles of epoxy compounds produced in the product / the number of moles of olefins consumed by all products × 100%

The effective utilization rate of hydrogen peroxide (%) = the number of moles of hydrogen peroxide consumed to generate all products / (the number of moles of hydrogen peroxide in the raw material - the number of moles of hydrogen peroxide in the product) × 100%

Preparation Example 1

This preparation example is used to prepare TS-1-A molecular sieve containing template agent.

About 3/4 of the tetrapropylammonium hydroxide (TPAOH, 20wt%) solution was added to the tetraethyl orthosilicate (TEOS) solution to obtain a liquid mixture with a pH of about 13, and then to the A required amount of anhydrous isopropanol solution of n-butyl titanate [Ti(OBu) ₄ ] was added dropwise to the obtained liquid mixture, and stirred for 15 minutes. Finally, the remaining TPAOH was slowly added to the mixture, and stirred at 348-353K for about 3 hours to obtain a sol with the chemical composition of 0.02TiO ₂ : SiO ₂ : 0.36TPA: 35H ₂ O, and then carried out at 443K After crystallization for 3 days, the resulting solid was filtered, washed with distilled water, and dried at 373K for 5 hours to obtain a molecular sieve sample, numbered TS-1-A.

The weight loss of TS-1-A measured between 200-600° C. by thermogravimetric method is 15%.

Preparation example 2

This preparation example is used to prepare TS-1-B molecular sieve containing template agent.

The difference from Preparation Example 1 is that a sol with a chemical composition of 0.008TiO ₂ :SiO ₂ :0.36TPA:35H ₂ O was obtained, and the molecular sieve sample number was TS-1-B.

The weight loss of TS-1-B at 200-600° C. was measured to be 12% by thermogravimetric method.

Comparative example 1

This comparative example illustrates the preparation of TS-1-C without template by air calcination.

TS-1-A was calcined at 550°C for 6 hours under air atmosphere and normal pressure to remove the template agent, and the molecular sieve sample number was TS-1-C. The weight loss of the treated molecular sieve at 200-600° C. is 0 as measured by thermogravimetric method. The TEM characterization results of the molecular sieves are shown in Figure 1. It can be seen that there is no obvious mesoporous structure in the molecular sieve crystals.

Comparative example 1

This comparative example illustrates the preparation of TS-1-D by calcining the titanium-silicon molecular sieve containing template agent after molding.

Tetraethyl silicate (calculated as silicon dioxide), tetraethyl titanate (calculated as titanium dioxide), and tetrapropylammonium hydroxide aqueous solution (calculated as water) with a pH value of 14 are molar ratio 1:0.05:10 Mix and treat at 80°C for 3 hours to obtain silica-titanium gel, and then mix TS-1-A, silica-titanium gel, additives, and ammonium chloride in a weight ratio of 100:3:6:0.1 for rolling ball molding, in which the additive It is composed of safflower powder and propylene glycol in a weight ratio of 1:2. Then, the molded catalyst was calcined at 550° C. under normal pressure and air atmosphere for 6 hours to remove the templating agent. The catalyst sample number was TS-1-D. The weight loss of the treated catalyst at 200-600° C. is 0 as measured by thermogravimetric method.

Example 1

This example illustrates the preparation of shaped titanium-containing catalyst TS-1-F by the method of the present invention.

In the first step, tetraethyl silicate (calculated as silicon dioxide), tetraethyl titanate (calculated as titanium dioxide), and tetrapropylammonium hydroxide aqueous solution (calculated as water) with a pH value of 14 are mixed in a molar ratio of 1 : 0.05:10 mixed at 80°C for 3 hours to obtain silicon-titanium rubber, and then TS-1-A, silicon-titanium rubber, additives, and ammonium chloride were mixed in a weight ratio of 100:3:6:0.1 for rolling ball molding , wherein the auxiliary agent is composed of scallop powder and propylene glycol in a weight ratio of 1:2.

In the second step, the molded catalyst was passed into water under the conditions of 120° C. and N2 back pressure of 0.45 MPa, and a water vapor atmosphere was generated for 2.5 hours. The rate of passing water was 0.1 g liquid/(g catalyst·min).

The 3rd step, continue at 350 DEG C, N The mass fraction of feeding under the condition of 0.2Mpa backpressure pressure is the ammoniacal liquor of 10%, and the recorded solution pH value is 14, and feeding rate is 0.3g liquid/(g catalyst·min) , the processing time is 4h.

The weight loss of the treated catalyst at 200-600° C. was measured to be 0.4% by using a thermogravimetric method. Calcined at 550°C under normal pressure and air atmosphere for 6h to remove residual template agent, the catalyst sample number is TS-1-F. The TEM results of the titanium-silicon molecular sieve after crushing the titanium-containing catalyst are shown in Figure 2. It can be seen that there are many 4-20nm mesoporous structures in the molecular sieve crystal.

Example 2

This example illustrates the preparation of shaped titanium-containing catalyst TS-1-G by the method of the present invention.

In the first step, tetraethyl silicate (calculated as silicon dioxide), tetraisopropyl titanate (calculated as titanium dioxide), and ammonia water with a pH value of 14 (calculated as water) are mixed in a molar ratio of 1:0.09:9 Treat at 60°C for 4 hours to obtain silica-titanium gel, and then mix TS-1-A, silica-titanium gel, additives, and ammonium bicarbonate in a weight ratio of 100:4:5:0.4 for rolling ball molding, wherein the additives are The composition of tianjing powder and fructose is 1:1.5 by weight.

In the second step, the molded catalyst was passed into water under the condition of 230° C. and N2 back pressure of 0.5 MPa, and a water vapor atmosphere was generated for 3 hours. The rate of passing water was 0.2 g liquid/(g catalyst·min).

The 3rd step, continue at 380 ℃, under the condition of N2 backpressure pressure 0.6Mpa, feed the ammoniacal liquor that mass fraction is 15%, record the solution pH value to be 14, feed rate is 0.4g liquid/(g catalyst · min) , the processing time is 4h.

The weight loss of the treated catalyst at 200-600° C. is 0.3% as measured by thermogravimetric method. Calcined at 550°C under normal pressure and air atmosphere for 6 hours to remove residual template agent, the catalyst sample number is TS-1-G. The TEM results of the titanium-silicon molecular sieve after crushing the titanium-containing catalyst show that there are many 4-20nm mesoporous structures in the molecular sieve crystal.

Example 3

This example illustrates the preparation of shaped titanium-containing catalyst TS-1-H by the method of the present invention.

In the first step, tetraethyl silicate (calculated as silicon dioxide), tetrabutyl titanate (calculated as titanium dioxide), and tetrabutylammonium hydroxide aqueous solution (calculated as water) with a pH value of 14 are mixed in a molar ratio of 1:0.05 : 3 mixed and treated at 70°C for 2 hours to obtain silica-titanium gel, and then mix TS-1-A, silica-titanium gel, ethylene glycol, and ammonium sulfate in a weight ratio of 100:20:5:2 for rolling ball molding. In the second step, the molded catalyst was passed into water under the condition of 280° C. and N2 back pressure of 0.6 MPa, and a water vapor atmosphere was generated for 3 hours. The rate of passing water was 0.9 g liquid/(g catalyst·min). The 3rd step, continue at 600 DEG C, N The mass fraction of feeding under the condition of 0.25Mpa backpressure pressure is the ammoniacal liquor of 20%, and the measured solution pH value is 14, and feeding rate is 1.8g liquid/(g catalyst·min) , the processing time is 5h.

The weight loss of the treated catalyst at 200-600° C. was measured to be 0.4% by using a thermogravimetric method. Calcined at 550°C under normal pressure and air atmosphere for 6h to remove residual template agent, the catalyst sample number is TS-1-H. The TEM results of the titanium-silicon molecular sieve after crushing the titanium-containing catalyst show that there are many 4-20nm mesoporous structures in the molecular sieve crystal.

Example 4

This example illustrates the preparation of shaped titanium-containing catalyst TS-1-I by the method of the present invention.

In the first step, tetraethyl ammonium hydroxide (calculated as silicon dioxide), tetraethyl titanate (calculated as titanium dioxide), and tetraethylammonium hydroxide aqueous solution (calculated as water) with a pH value of 13 are mixed in a molar ratio of 1 : 0.3:10 mixed at 60°C for 3 hours to obtain silica-titanium gel, and then TS-1-A, silica-titanium gel, additives, and ammonium dihydrogen phosphate were mixed and kneaded at a weight ratio of 100:16:6:1.6. Then carry out extrusion molding, wherein the auxiliary agent is composed of starch and hexanediol in a weight ratio of 1:3.

In the second step, the molded catalyst was passed into water under the condition of 140° C. and N2 back pressure of 0.15 MPa, and a water vapor atmosphere was generated for 2.5 hours. The rate of passing water was 1.2 g liquid/(g catalyst·min).

The 3rd step, continue at 30 DEG C, N The mass fraction of feeding under the condition of 0.6Mpa backpressure pressure is the ammoniacal liquor of 15%, and the recorded solution pH value is 14, and feeding rate is 1.5g liquid/(g catalyst · min) , the processing time is 3h.

The weight loss of the treated catalyst at 200-600° C. is 0.3% as measured by thermogravimetric method. Calcined at 550°C under normal pressure and air atmosphere for 6h to remove residual template agent, the catalyst sample number is TS-1-I. The TEM results of the titanium-silicon molecular sieve after crushing the titanium-containing catalyst show that there are many 4-20nm mesoporous structures in the molecular sieve crystal.

Example 5

This example illustrates the preparation of shaped titanium-containing catalyst TS-1-J by the method of the present invention.

In the first step, silica sol (30%, calculated as silicon dioxide), titanium sulfate (calculated as titanium dioxide), and tetrapropylammonium hydroxide aqueous solution (calculated as water) with a pH value of 13 are mixed in a molar ratio of 1:0.05: 3 Mix and treat at 90°C for 4 hours to obtain silica-titanium gel, and then mix TS-1-A, silica-titanium gel, additives, and ammonium nitrate in a weight ratio of 100:4:5:0.3 for rolling ball molding, in which the additive It is composed of starch and glyceraldehyde in a weight ratio of 1:1.5.

In the second step, the molded catalyst was passed into water under the condition of 260° C. and N2 back pressure of 0.5 MPa, and a water vapor atmosphere was generated for 3 hours. The rate of passing water was 0.85 g liquid/(g catalyst·min).

The 3rd step, continue at 350 DEG C, N2 under the condition of backpressure pressure 0.25Mpa, pass into the propylamine that massfraction is 28%, record solution pH value to be 13, pass rate is 0.4g liquid/(g catalyzer · min) , the processing time is 4h. The weight loss of the treated catalyst at 200-600° C. was measured to be 0.4% by using a thermogravimetric method. Calcined at 550°C under normal pressure and air atmosphere for 6h to remove residual template agent, the catalyst sample number is TS-1-J. The TEM results of the titanium-silicon molecular sieve after crushing the titanium-containing catalyst show that there are many 4-20nm mesoporous structures in the molecular sieve crystal.

Example 6

This example illustrates the preparation of shaped titanium-containing catalyst TS-1-K by the method of the present invention.

In the first step, tetraethyl silicate (calculated as silicon dioxide), tetrabutyl titanate (calculated as titanium dioxide), and ammonia solution with a pH value of 13 (calculated as water) are mixed in a molar ratio of 1:0.09:9 Treat at 60°C for 5 hours to obtain silica-titanium gel, and then mix TS-1-A, silica-titanium gel, additives, and ammonium bisulfate in a weight ratio of 100:18:6:1.8 for rolling ball molding, wherein the additives are The composition of tianjing powder and glycerin is 1:2.5 by weight.

In the second step, the molded catalyst was passed into water under the conditions of 220° C. and N2 back pressure of 0.7 MPa, and a water vapor atmosphere was generated for 2.5 hours. The rate of passing water was 0.25 g liquid/(g catalyst·min).

The 3rd step, continue at 600 DEG C, N Under the condition of backpressure pressure 0.7Mpa, pass into the ammoniacal liquor that massfraction is 25%, record solution pH value to be 14, pass rate is 2g liquid/(g catalyzer · min), The processing time is 3h.

The weight loss of the treated catalyst at 200-600° C. is 0.3% as measured by thermogravimetric method. Calcined at 550°C under normal pressure and air atmosphere for 6 hours to remove residual template agent, the catalyst sample number is TS-1-K. The TEM results of the titanium-silicon molecular sieve after crushing the titanium-containing catalyst show that there are many 4-20nm mesoporous structures in the molecular sieve crystal.

Example 7

This example illustrates the preparation of shaped titanium-containing catalyst TS-1-L by the method of the present invention.

In the first step, tetraethyl silicate (calculated as silicon dioxide), tetraisopropyl titanate (calculated as titanium dioxide), and ammonia solution with a pH value of 14 (calculated as water) are mixed in a molar ratio of 1:0.1:4 Mix and treat at 70°C for 4 hours to obtain silica-titanium gel, then mix and knead TS-1-A, silica-titanium gel, additives, and ammonium acetate at a weight ratio of 100:5:1:0.5, and then perform extrusion molding. The auxiliary agent is composed of scallop powder and pentaerythritol in a weight ratio of 1:3.

In the second step, the molded catalyst was passed into water under the conditions of 200° C. and N2 back pressure of 0.2 MPa, and a water vapor atmosphere was generated for 1.5 hours, and the rate of passing water was 0.3 g liquid/(g catalyst·min).

The 3rd step, continue at 400 DEG C, N Under the condition of backpressure pressure 0.3Mpa, pass into the ammoniacal liquor that massfraction is 15%, record solution pH value to be 14, pass rate is 1g liquid/(g catalyzer · min), The processing time is 4h.

The weight loss of the treated catalyst at 200-600° C. is 0.1% as measured by thermogravimetric method. Calcined at 550°C under normal pressure and air atmosphere for 6h to remove residual template agent, the catalyst sample number is TS-1-L. The TEM results of the titanium-silicon molecular sieve after crushing the titanium-containing catalyst show that there are many 4-20nm mesoporous structures in the molecular sieve crystal.

Example 8

This example illustrates the preparation of shaped titanium-containing catalyst TS-1-M by the method of the present invention.

In the first step, tetraethyl silicate (calculated as silicon dioxide), tetrabutyl titanate (calculated as titanium dioxide), and tetrapropylammonium hydroxide aqueous solution (calculated as water) with a pH value of 14 are mixed in a molar ratio of 1 : 0.25:8 mixed at 80°C for 4 hours to obtain silica-titanium gel, and then mix TS-1-A, silica-titanium gel, additives, and ammonium carbonate in a weight ratio of 100:10:4:1.5 for rolling ball molding. The auxiliary agent is composed of starch and dihydroxyacetone in a weight ratio of 1:1.5.

In the second step, the molded catalyst was passed into water under the conditions of 150° C. and N2 back pressure of 0.3 MPa, and a water vapor atmosphere was generated for 1.5 hours, and the rate of passing water was 0.5 g liquid/(g catalyst·min).

The 3rd step, continue at 450 DEG C, N The mass fraction of feeding under the condition of 0.3Mpa backpressure pressure is the ammoniacal liquor of 5%, and the recorded solution pH value is 14, and feeding rate is 1.2g liquid/(g catalyst·min) , the processing time is 6h.

The weight loss of the treated catalyst at 200-600° C. is 0.1% as measured by thermogravimetric method. Calcined at 550°C under normal pressure and air atmosphere for 6h to remove residual template agent, the catalyst sample number is TS-1-M. The TEM results of the titanium-silicon molecular sieve after crushing the titanium-containing catalyst show that there are many 4-20nm mesoporous structures in the molecular sieve crystal.

Example 9

This example illustrates the preparation of shaped titanium-containing catalyst TS-1-N by the method of the present invention.

In the first step, tetraethyl ammonium hydroxide (calculated as silicon dioxide), tetraethyl titanate (calculated as titanium dioxide), and tetraethylammonium hydroxide aqueous solution (calculated as water) with a pH value of 14 are mixed in a molar ratio of 1 : 0.15:6 mixed at 80°C for 3 hours to obtain silica-titanium gel, and then mix TS-1-A, silica-titanium gel, additives, and ammonium phosphate in a weight ratio of 100:15:3:1 for rolling ball molding. The auxiliary agent is composed of starch and glycerin in a weight ratio of 1:2.

In the second step, the molded catalyst was passed into water under the conditions of 200° C. and N2 back pressure of 0.2 MPa, and a water vapor atmosphere was generated for 1.5 hours, and the rate of passing water was 0.8 g liquid/(g catalyst·min).

The 3rd step, continue at 550 DEG C, N The mass fraction of feeding under the condition of 0.45Mpa back pressure pressure is the ammoniacal liquor of 20%, and the recorded solution pH value is 14, and feeding rate is 0.6g liquid/(g catalyst·min) , the processing time is 4h.

The weight loss of the treated catalyst at 200-600° C. is 0.1% as measured by thermogravimetric method. The catalyst sample number is TS-1-N. The TEM results of the titanium-silicon molecular sieve after crushing the titanium-containing catalyst show that there are many 4-20nm mesoporous structures in the molecular sieve crystal.

Example 10

This example illustrates the preparation of shaped titanium-containing catalyst TS-1-O by the method of the present invention.

In the first step, tetraethyl silicate (calculated as silicon dioxide), tetrabutyl titanate (calculated as titanium dioxide), and tetrabutylammonium hydroxide aqueous solution (calculated as water) with a pH value of 14 are mixed in a molar ratio of 1:0.2 : 5 mixed at 60°C for 4 hours to obtain silica-titanium gel, and then TS-1-A, silica-titanium gel, additives, and ammonium fluoride were mixed in a weight ratio of 100:8:2:0.7 for rolling ball molding, of which The auxiliary agent is composed of sage powder and glucose in a weight ratio of 1:1.5.

In the second step, the molded catalyst was passed into water under the conditions of 150° C. and N2 back pressure of 0.4 MPa, and a water vapor atmosphere was generated for 1.5 hours. The rate of passing water was 0.4 g liquid/(g catalyst·min).

The 3rd step, continue at 500 DEG C, N The mass fraction of feeding under the condition of 0.5Mpa backpressure pressure is the ammoniacal liquor of 10%, and the recorded solution pH value is 14, and feeding rate is 1.4g liquid/(g catalyst·min) , the processing time is 5h.

The weight loss of the treated catalyst at 200-600° C. is 0.1% as measured by thermogravimetric method. The catalyst sample number is TS-1-O. The TEM results of the titanium-silicon molecular sieve after crushing the titanium-containing catalyst show that there are many 4-20nm mesoporous structures in the molecular sieve crystal.

Example 11

This example illustrates the preparation of shaped titanium-containing catalyst TS-1-P by the method of the present invention.

Mix TS-1-N with an ammonia solution with a pH value of 11 at a catalyst mass fraction of 5%, treat it at 60°C for 60 minutes, then separate the catalyst, and further mix it with a nitric acid solution with a pH value of 2 and containing 2% hydrogen peroxide at a molecular sieve mass fraction 3% mixed, treated at 80 °C for 60 min, and then the catalyst was separated. The sample number is TS-1-P.

The TEM results of the titanium-silicon molecular sieve after crushing the titanium-containing catalyst show that there are still many 4-20nm mesoporous structures in the molecular sieve crystal.

Example 12

This example illustrates the preparation of shaped titanium-containing catalyst TS-1-Q by the method of the present invention.

Mix TS-1-O with an ammonia solution with a pH value of 10 at a catalyst mass fraction of 4%, treat at 80°C for 60 minutes, then separate the catalyst, and further mix it with a hydrochloric acid solution with a pH value of 3 and containing 1% hydrogen peroxide at a molecular sieve mass fraction 5% mixed, treated at 60 °C for 60 min, and then the catalyst was separated. The sample number is TS-1-Q. The TEM results of the titanium-silicon molecular sieve after crushing the titanium-containing catalyst show that there are still many 4-20nm mesoporous structures in the molecular sieve crystal.

Evaluation Comparative Example 1, Evaluation Comparative Example 1, Evaluation Examples 1-12

The catalyst was used for the epoxidation of propylene to produce propylene oxide as follows.

Fill the catalyst into a fixed bed reactor, then introduce hydrogen peroxide, propylene, and methanol into the catalyst bed at a molar ratio of 1:2:7, control the reaction temperature at 40°C, the reaction pressure at 2MPa, and the weight hourly space velocity of the reaction material at 2h-1. After 2 hours of stabilization, samples were taken for analysis. The results are shown in Table 1.

Table 1

From Examples 1-12, Comparative Example 1, and Comparative Example 1, it can be seen that the titanium-containing catalyst provided by the present invention has a simple process, is easy to implement, has good effect, can effectively use molecular sieve intracrystalline templates, and produces small-sized mesoporous structures .

As can be seen from Evaluation Examples 1-12, Evaluation Comparative Example 1, and Evaluation Comparative Example 1, the titanium-containing catalyst provided by the present invention, when used for propylene epoxidation to prepare propylene oxide, has high catalytic activity, high conversion rate of raw materials, It has the characteristics of high selectivity of propylene oxide and high effective utilization rate of hydrogen peroxide.

The preferred embodiments of the present disclosure have been described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure. These simple modifications all belong to the protection scope of the present disclosure.

In addition, it should be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner if there is no contradiction. The combination method will not be described separately.

In addition, any combination of various implementations of the present disclosure can also be made, as long as they do not violate the idea of the present disclosure, they should also be regarded as the content disclosed in the present invention.

Claims (15)

1. a preparation method containing titanium catalyst, is characterized in that, the method comprises the steps: (1) Mix and heat treat amorphous silicon source, titanium source, and alkaline aqueous solution to prepare silicon-titanium gel, and then mix it with titanium-silicon molecular sieve, additives, and ammonium salt to obtain a molding catalyst; the titanium-silicon molecular sieve contains template agent, template The content of the additive accounts for 1-30% of the weight of the titanium silicon molecular sieve; the additive is selected from one or more of kale powder, starch, polyol, and nanocellulose; (2) Treat the shaped catalyst for 0.5-3h under the conditions of external pressure and external addition of water, the apparent pressure is 0.01-1.0MPa, and the temperature is 100-300°C; the water is preheated and vaporized to produce The gas is in contact with the shaped catalyst; (3) Treat the shaped catalyst obtained in (2) with a superficial pressure of 0.01-1.0 MPa and a temperature of 300-600° C. for at least 0.5 h to obtain a titanium-containing catalyst. 2. The method according to claim 1, wherein the molding in step (1) includes rolling ball molding, extrusion molding after kneading. 3. The method according to claim 1, wherein the amorphous silicon source in step (1) includes silica sol or organic silicon ester; the titanium source includes organic titanium ester, titanium tetrachloride, titanium trichloride, Titanium sulfate; the alkaline aqueous solution is an aqueous solution containing an organic base or an inorganic base with a pH value of 10-14; the ammonium salt is an organic ammonium salt or an inorganic ammonium salt, and the heat treatment includes a temperature of 50-100°C Under treatment for 0.5-5h. 4. The method according to claim 1, wherein, in the silica-titanium gel described in step (1), the molar ratio of amorphous silicon source, titanium source, and water is 1: (0.05-0.30): (3-10), The amorphous silicon source is counted as silicon dioxide, and the titanium source is counted as titanium dioxide; the titanium-silicon molecular sieve, silicon-titanium colloid, additives, and ammonium salt are in a weight ratio of 100: (3-20): (1-6) : (0.1-2). 5. The method according to claim 1, wherein the superficial pressure in step (2) is 0.1-0.6 MPa, and the superficial pressure in step (3) is 0.2-0.7 MPa. 6. The method according to claim 1, wherein the titanium-silicon molecular sieve in step (1) has an MFI structure. 7. The method according to claim 1, wherein the liquid with a pH value >9 in step (3) is ammonia water or an aqueous solution of organic amines, and the mass fraction of alkaline substances in the liquid is 1-28%. 8. The method according to claim 1, wherein step (3) comprises preheating and vaporizing the liquid with a pH value > 9, and contacting the generated gas with the shaped catalyst. 9. The method according to claim 1, wherein, in the steps (2) and (3), the amount of the water or the liquid with a pH value>9 is (0.1-2) g/(g shaped catalyst· min). 10. The method according to claim 1, further comprising calcining the shaped catalyst in an oxygen-containing atmosphere. 11. The method according to claim 10, further comprising performing alkaline washing and acid washing on the titanium-containing catalyst. 12. The method according to claim 11, wherein the titanium-containing catalyst is alkali-washed with an ammonia solution, and acid-washed with an acid solution containing hydrogen peroxide. 13. A titanium-containing catalyst, characterized in that it is prepared by the method according to any one of claims 1-12. 14. A method for preparing epoxy compounds by epoxidation of olefins, characterized in that, under epoxidation reaction conditions, in the presence of the titanium-containing catalyst of claim 13, olefins, hydrogen peroxide and solvents are contacted to obtain epoxy compounds containing product of. 15. The method according to claim 14, wherein said olefin is propylene.

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