Preparation method and application of catalyst for preparing epoxy chloropropane

Abstract

The invention provides a preparation method and application of a catalyst for preparing epoxy chloropropane. The preparation method comprises the following steps: dissolving or dispersing titanium salt in an organic solvent to form a solution or slurry; dispersing silicon dioxide in the solution or the slurry to form silicon dioxide-containing slurry; carrying out sanding treatment on the silicon dioxide-containing slurry; the sanding slurry enters a heat treatment device for controlled heat treatment, high-temperature air is introduced, no external heat source exists, and the target catalyst is obtained after treatment. In the preparation process of the catalyst, heat released by combustion of an organic solvent in precursor slurry is utilized to realize heat treatment, the solvent with proper combustion heat is selected, the heat treatment process is effectively controlled, particles are quickly decomposed by the heat released by the combustion of the solvent, and the optimal shrinkage effect is achieved; the catalyst inactivation caused by the blockage of the pore channel by the by-product can be reduced. The catalyst obtained by the method has excellent activity, selectivity and stability.

Description

Technical Field

[0001] The present invention belongs to the field of catalysts, and particularly relates to a preparation method and application of a catalyst for preparing epichlorohydrin. Background Art

[0002] Epichlorohydrin is an important organic intermediate used in the synthesis of important chemical products such as chlorohydrin rubber and synthetic epoxy resins. Compared with the traditional high-temperature propylene chlorination method, allyl acetate method, and the glycerol method for synthesizing epichlorohydrin developed in recent years, the method of synthesizing epichlorohydrin by the oxidation of 3-chloropropene with hydrogen peroxide has the advantages of no pollution, high conversion rate, high selectivity, and mild reaction conditions, and will be the preferred process for producing epichlorohydrin in the future.

[0003] Titanium silicalite (TS-1) is the most mainstream catalyst for the direct oxidation of allyl chloride with H2O2 to produce epichlorohydrin, which has the advantages of mild reaction conditions and high activity. However, the pores of the MFI structure of titanium silicalite are relatively narrow, and by-products such as the polymerization of 3-chloropropene and the ring-opening etherification of epichlorohydrin during the reaction are likely to cause pore blockage and deactivation. Patent CN114904572A reports a titanium silicalite catalyst containing hierarchical pores, which is obtained by hydrothermal treatment with an organic amine template at a higher temperature, followed by calcination after treatment with water-soluble alcohols, ketones, and esters. The prepared titanium silicalite catalyst has a micro-mesoporous structure, which can reduce the catalyst deactivation caused by pore blockage due to product polymerization. Patent CN 116586051 A reports a Ti / SiO2 catalyst, which is synthesized by grafting titanium tetrachloride on amorphous silica powder in a liquid-solid phase reaction manner using a lower alcohol as a solvent, and the prepared amorphous Ti / SiO2 catalyst has a titanium active center structure completely different from that of titanium silicalite TS-1. Regardless of the type of catalyst, during the catalyst preparation process, it usually starts from a solution or slurry, undergoes processes such as drying and calcination to obtain the final catalyst. The whole process has many steps, high equipment investment, and usually requires high energy consumption for drying, calcination, etc.

[0004] Therefore, it is of great basic research and industrial application value to develop a preparation method for epoxidation catalysts with a short process, low energy consumption, and controllable process. Summary of the Invention

[0005] One of the objectives of the present invention is to provide a preparation method for a catalyst for preparing epichlorohydrin, and the catalyst obtained by this method has excellent activity, selectivity, and stability.

[0006] To achieve the above-mentioned invention objective, the technical solution of the present invention is as follows:

[0007] A preparation method of a catalyst for preparing epichlorohydrin, the preparation method comprising the following steps:

[0008] S1: Dissolve or disperse a titanium salt in an organic solvent to form a solution or slurry;

[0009] S2: Disperse silica in the solution or slurry of S1 to form a silica-containing slurry;

[0010] S3: Grind the silica-containing slurry of S2;

[0011] S4: The ground slurry of S3 enters a heat treatment device for controlled heat treatment, high-temperature air is introduced, there is no external heat source, and the target catalyst is obtained after treatment.

[0012] The inventor found that during the catalyst preparation process, the heat released by the combustion of the organic solvent in the precursor slurry is used to achieve heat treatment. By selecting a solvent with an appropriate heat of combustion and without using an external heat source, the heat treatment process can be effectively controlled. The heat released by the solvent combustion causes the particles to decompose rapidly and achieves the best shrinkage effect, which helps to reduce the catalyst deactivation caused by by-product blockage of pores.

[0013] In an embodiment of the present invention, the titanium salt in S1 is a titanium inorganic acid salt, preferably TiCl4 and / or Ti(SO4)2.

[0014] In an embodiment of the present invention, the organic solvent in S1 is an organic solvent with a heat of combustion of 200 - 1200 kcal / mol, preferably a ketone solvent, more preferably acetone and / or butanone; preferably, the mass ratio of the titanium salt to the organic solvent is 0.8% - 13.6%.

[0015] In an embodiment of the present invention, the mass ratio of the titanium salt to silica in S2 is 1:(10 - 50).

[0016] In an embodiment of the present invention, the total mass fraction of the titanium salt and silica in the silica-containing slurry of S2 is 30% - 60%, preferably 30% - 40%.

[0017] In an embodiment of the present invention, when grinding in S3, the rotation speed of the grinder is 1000 - 2500 revolutions per minute, and the treatment time is 1 - 10 h.

[0018] In an embodiment of the present invention, the feeding speed of the ground slurry in S4 is 50 ml / h - 2000 ml / h.

[0019] In an embodiment of the present invention, the feeding speed of high-temperature air in S4 is 10 m 3 / h - 100 m 3 / h.

[0020] In one embodiment of the present invention, the high-temperature air feed temperature in S4 is 100 - 500 °C.

[0021] Another object of the present invention is to provide a catalyst for preparing epichlorohydrin.

[0022] A catalyst for preparing epichlorohydrin, wherein the catalyst is the catalyst prepared by the above preparation method, and the catalyst contains titanium element and silicon dioxide.

[0023] Yet another object of the present invention is to provide a use of a catalyst for preparing epichlorohydrin.

[0024] A use of a catalyst for preparing epichlorohydrin, wherein the catalyst is the catalyst prepared by the above preparation method, or the above catalyst, and the catalyst is used for catalyzing the reaction of allyl chloride with hydrogen peroxide to prepare epichlorohydrin.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] The prepared catalyst has good thermal conductivity and mass transfer performance, and has excellent activity, selectivity and stability. The conversion rate of H2O2 > 99.5%, and the selectivity of epichlorohydrin > 99.0%; after running for 2500 h, the conversion rate of H2O2 is still > 99.0%, and the selectivity of epichlorohydrin > 97.0%. Specific Examples

[0027] Main raw material information

[0028] Main raw materials Manufacturer Specification Titanium tetrachloride Aladdin 99.5％ Titanium sulfate Sinopharm Chemical Reagent Co., Ltd. 96.0％ Silicon dioxide Aladdin - Acetone Sinopharm Chemical Reagent Co., Ltd. 99.5％ Butanone Sinopharm Chemical Reagent Co., Ltd. 99.0％ Methanol Sinopharm Chemical Reagent Co., Ltd. 99.7％

[0029] Main equipment information

[0030] Equipment name Manufacturer Model Sand mill Langling NT-V1L Controlled heat treatment device Yantai Keli Non-standard customization

[0031] Analysis and characterization methods

[0032] For the reaction of oxidizing 3-chloropropene to epichlorohydrin mentioned in the present invention, the conversion rate of hydrogen peroxide is analyzed by titration method. The brand model of the titrator used is Metrohm 905 Titrando. Sodium thiosulfate solution is used to titrate hydrogen peroxide to measure the concentration of hydrogen peroxide, and the conversion rate of hydrogen peroxide is calculated according to the concentration of hydrogen peroxide. The calculation formula is as follows:

[0033]

[0034] The selectivity of epichlorohydrin is analyzed by gas chromatography. The brand model of the gas chromatograph used is Agilent 7820A, and the selectivity of different products is calculated by the corrected area normalization method.

[0035] Example 1

[0036] S1: Weigh 50 g of titanium tetrachloride and add it to 6250 g of acetone (the heat of combustion of acetone is 427.92 kcal / mol) to form a solution.

[0037] S2: Add 2628 g of silica to the solution in S1 to obtain a slurry.

[0038] S3: Grind the slurry obtained in S2 in a sand mill for 1 h at a grinding speed of 2500 revolutions per minute to obtain a precursor slurry.

[0039] S4: Carry out controlled heat treatment on the slurry formed in S3 in a heat treatment device. Set the air inlet temperature to 470 °C and the inlet air volume to 10 m 3 / h. Feed the slurry obtained in S3 into the heat treatment device at a feeding speed of 50 ml / h. Set the atomizer speed to 300 revolutions per minute. After 1 min, set the air inlet temperature to 100 °C. After the feeding is completed, a catalyst is obtained.

[0040] Example 2

[0041] S1: Weigh 50 g of titanium tetrachloride and add it to 368 g of acetone (the heat of combustion of acetone is 427.92 kcal / mol) to form a solution.

[0042] S2: Add 500 g of silica to the solution in S1 to obtain a slurry.

[0043] S3: Grind the slurry obtained in S2 in a sand mill for 1 h at a grinding speed of 2500 revolutions per minute to obtain a precursor slurry.

[0044] S4: Carry out controlled heat treatment on the slurry formed in S3 in a heat treatment device. Set the air inlet temperature to 470 °C and the inlet air volume to 10 m 3 / h. Feed the slurry obtained in S3 into the heat treatment device at a feeding speed of 50 ml / h. Set the atomizer speed to 300 revolutions per minute. After 1 min, set the air inlet temperature to 100 °C. After the feeding is completed, a catalyst is obtained.

[0045] Example 3

[0046] S1: Weigh 50 g of titanium tetrachloride and add it to 825 g of acetone (the heat of combustion of acetone is 427.92 kcal / mol) to form a solution.

[0047] S2: Add 500 g of silica to the solution in S1 to obtain a slurry.

[0048] S3: Grind the slurry obtained in S2 in a sand mill for 1 h at a grinding speed of 2500 revolutions per minute to obtain a precursor slurry.

[0049] S4: Subject the slurry formed in S3 to controlled heat treatment in a heat treatment device. Set the air inlet temperature to 470 °C, the inlet air volume to 10 m 3 / h. Feed the slurry obtained in S3 into the heat treatment device at a feed rate of 50 ml / h. Set the atomizer rotation speed to 300 revolutions per minute. After 1 minute, set the air inlet temperature to 100 °C. After the feeding is completed, a catalyst is obtained.

[0050] Example 4

[0051] S1: Weigh 50 g of titanium tetrachloride and add it to 825 g of acetone (the heat of combustion of acetone is 427.92 kcal / mol) to form a solution.

[0052] S2: Add 500 g of silica to the solution of S1 to obtain a slurry.

[0053] S3: Grind the slurry obtained in S2 in a sand mill for 10 h at a grinding speed of 2500 revolutions per minute to obtain a precursor slurry.

[0054] S4: Subject the slurry formed in S3 to controlled heat treatment in a heat treatment device. Set the air inlet temperature to 470 °C, the inlet air volume to 10 m 3 / h. Feed the slurry obtained in S3 into the heat treatment device at a feed rate of 50 ml / h. Set the atomizer rotation speed to 300 revolutions per minute. After 1 minute, set the air inlet temperature to 100 °C. After the feeding is completed, a catalyst is obtained.

[0055] Example 5

[0056] S1: Weigh 50 g of titanium tetrachloride and add it to 825 g of acetone (the heat of combustion of acetone is 427.92 kcal / mol) to form a solution.

[0057] S2: Add 500 g of silica to the solution of S1 to obtain a slurry.

[0058] S3: Grind the slurry obtained in S2 in a sand mill for 1 h at a grinding speed of 1000 revolutions per minute to obtain a precursor slurry.

[0059] S4: Subject the slurry formed in S3 to controlled heat treatment in a heat treatment device. Set the air inlet temperature to 470 °C, the inlet air volume to 10 m 3 / h. Feed the slurry obtained in S3 into the heat treatment device at a feed rate of 50 ml / h. Set the atomizer rotation speed to 300 revolutions per minute. After 1 minute, set the air inlet temperature to 100 °C. After the feeding is completed, a catalyst is obtained.

[0060] Example 6

[0061] S1: Weigh 50 g of titanium tetrachloride and add it to 825 g of acetone (the heat of combustion of acetone is 427.92 kcal / mol) to form a solution.

[0062] S2: Add 500 g of silica to the solution of S1 to obtain a slurry.

[0063] S3: Grind the slurry obtained in S2 in a sand mill for 1 h at a grinding speed of 2500 revolutions per minute to obtain a precursor slurry.

[0064] S4: Carry out controlled heat treatment on the slurry formed in S3 in a heat treatment device. Set the air inlet temperature to 470 °C and the air intake volume to 10 m 3 / h. Feed the slurry obtained in S3 into the heat treatment device at a feeding speed of 2000 ml / h. Set the atomizer speed to 300 revolutions per minute. After 1 min, set the air inlet temperature to 100 °C. After the feeding is completed, a catalyst is obtained.

[0065] Example 7

[0066] S1: Weigh 50 g of titanium tetrachloride and add it to 825 g of acetone (the heat of combustion of acetone is 427.92 kcal / mol) to form a solution.

[0067] S2: Add 500 g of silica to the solution of S1 to obtain a slurry.

[0068] S3: Grind the slurry obtained in S2 in a sand mill for 1 h at a grinding speed of 2500 revolutions per minute to obtain a precursor slurry.

[0069] S4: Carry out controlled heat treatment on the slurry formed in S3 in a heat treatment device. Set the air inlet temperature to 470 °C and the air intake volume to 100 m 3 / h. Feed the slurry obtained in S3 into the heat treatment device at a feeding speed of 50 ml / h. Set the atomizer speed to 300 revolutions per minute. After 1 min, set the air inlet temperature to 100 °C. After the feeding is completed, a catalyst is obtained.

[0070] Example 8

[0071] S1: Weigh 50 g of titanium tetrachloride and add it to 825 g of butanone (the heat of combustion of butanone is 584.17 kcal / mol) to form a solution.

[0072] S2: Add 500 g of silica to the solution of S1 to obtain a slurry.

[0073] S3: Grind the slurry obtained in S2 in a sand mill for 1 h at a grinding speed of 2500 revolutions per minute to obtain a precursor slurry.

[0074] S4: The slurry formed in S3 is subjected to controlled heat treatment in a heat treatment device. Set the air inlet temperature to 500 °C and the inlet air volume to 10 m 3 / h. Feed the slurry obtained in S3 into the heat treatment device at a feed rate of 50 ml / h. Set the atomizer rotation speed to 300 revolutions per minute. After 1 min, set the air inlet temperature to 100 °C. After the feeding is completed, a catalyst is obtained.

[0075] Example 9

[0076] S1: Weigh 50 g of titanium sulfate and add it to 825 g of acetone (the heat of combustion of acetone is 427.92 kcal / mol) to form a slurry.

[0077] S2: Add 500 g of silica to the solution of S1 to obtain a slurry.

[0078] S3: The slurry obtained in S2 is milled in a sand mill for 1 h at a milling speed of 2500 revolutions per minute to obtain a precursor slurry.

[0079] S4: The slurry formed in S3 is subjected to controlled heat treatment in a heat treatment device. Set the air inlet temperature to 500 °C and the inlet air volume to 10 m 3 / h. Feed the slurry obtained in S3 into the heat treatment device at a feed rate of 50 ml / h. Set the atomizer rotation speed to 300 revolutions per minute. After 1 min, set the air inlet temperature to 100 °C. After the feeding is completed, a catalyst is obtained.

[0080] Comparative Example 1

[0081] The difference lies in adopting a process including calcination.

[0082] S1: Weigh 50 g of titanium tetrachloride and add it to 6250 g of acetone (the heat of combustion of acetone is 427.92 kcal / mol) to form a solution.

[0083] S2: Add 2628 g of silica to the solution of S1 to obtain a slurry.

[0084] S3: The slurry obtained in S2 is milled in a sand mill for 1 h at a milling speed of 2500 revolutions per minute to obtain a precursor slurry.

[0085] S4: Dry the slurry formed in S3 in an oven at 100 °C for 10 h; then calcine the dried sample in a muffle furnace at 600 °C for 5 h to obtain a catalyst.

[0086] Comparative Example 2

[0087] Compared with Example 1, the difference lies in adopting other organic solvents.

[0088] S1: Weigh 50 g of titanium tetrachloride and add it to 6250 g of methanol (the heat of combustion of methanol is 173.76 kcal / mol) to form a solution.

[0089] S2: Add 2628 g of silicon dioxide to the solution of S1 to obtain a slurry.

[0090] S3: Grind the slurry obtained in S2 in a sand mill for 1 h at a grinding speed of 2500 revolutions per minute to obtain a precursor slurry.

[0091] S4: Carry out controlled heat treatment on the slurry formed in S3 in a heat treatment device. Set the air inlet temperature to 470 °C and the air inlet volume to 10 m 3 / h. Feed the slurry obtained in S3 into the heat treatment device at a feeding speed of 50 ml / h. Set the atomizer speed to 300 revolutions per minute. After 1 min, set the air inlet temperature to 100 °C. After the feeding is completed, a catalyst is obtained.

[0092] Application Example

[0093] Catalyst Performance Evaluation: The above catalyst performance evaluation is carried out by the following steps. The catalyst evaluation uses a fixed-bed tubular reactor (using jacketed circulating water to remove heat). The inner diameter of the reaction tube is 25 mm, the filling height of the catalyst is 20 cm, and the molar ratio of raw materials allyl chloride, methanol and hydrogen peroxide is 3:10:1; the initial set temperature of the circulating water is 20 °C, the reaction pressure is 0.5 mPaG, and the space velocity based on hydrogen peroxide is 0.2 h -1 . After the reaction feed is stable for 4 h, samples are taken for analysis, and the reaction results are shown in Table 1.

[0094] Table 1 Catalyst Evaluation Results

[0095]

Claims

1. A preparation method of a catalyst for preparing epichlorohydrin, characterized in that, The preparation method comprises the following steps: S1: Dissolve or disperse a titanium salt in an organic solvent to form a solution or slurry; S2: Disperse silica in the solution or slurry of S1 to form a silica-containing slurry; S3: Subject the silica-containing slurry of S2 to sanding treatment; S4: The sanded slurry of S3 enters a heat treatment device for controlled heat treatment, high-temperature air is introduced, there is no external heat source, and the target catalyst is obtained after treatment.

2. The preparation method according to claim 1, characterized in that, The titanium salt described in S1 is an inorganic titanium salt, preferably TiCl4 and / or Ti(SO4)2; And / or, the organic solvent described in S1 is an organic solvent with a combustion heat of 400 - 900 kcal / mol, preferably a ketone solvent, more preferably acetone and / or methyl ethyl ketone; Preferably, the mass ratio of the titanium salt to the organic solvent is 0.8% - 13.6%.

3. The preparation method according to claim 1, characterized in that, The mass ratio of the titanium salt to silica in S2 is 1:(10 - 50); And / or, the total mass fraction of the titanium salt and silica in the silica-containing slurry described in S2 is 30% - 60%, preferably 30% - 40%.

4. The preparation method according to claim 1, characterized in that, During the sanding treatment in S3, the rotation speed of the sanding machine is 1000 - 2500 revolutions per minute, and the treatment time is 1 - 10 h.

5. The preparation method according to claim 1, characterized in that, The feeding speed of the sanded slurry in S4 is 50 ml / h - 2000 ml / h; and / or, the high-temperature air feeding speed in S4 is 10 m 3 / h to 100 m 3 / h; And / or, the feeding temperature of the high-temperature air in S4 is 100 - 500 °C.

6. A catalyst for preparing epichlorohydrin, wherein the catalyst is the catalyst prepared by the preparation method according to any one of claims 1-5, characterized in that, The catalyst contains titanium element and silica.

7. A use of a catalyst for preparing epichlorohydrin, wherein the catalyst is the catalyst prepared by the preparation method according to any one of claims 1-5, or the catalyst according to claim 6, and the catalyst is used for catalyzing the reaction of allyl chloride with hydrogen peroxide to prepare epichlorohydrin.

Images