Catalyst for preparing epichlorohydrin through catalytic oxidation of 3-chloropropene

Abstract

The invention provides a catalyst for preparing epichlorohydrin by catalyzing hydrogen peroxide to oxidize 3-chloropropene. The preparation method comprises the following steps: putting silicon carbide into a reactor, heating, introducing pretreatment gas, a pretreatment auxiliary agent and a reaction gas mixture, and roasting under the condition of introducing the pretreatment gas, the pretreatment auxiliary agent and the reaction gas mixture; stopping introducing the reaction gas mixture, and continuously roasting under the condition of introducing the pretreatment gas and the pretreatment auxiliary agent; introducing an inert atmosphere, cooling, and taking out a roasted sample; dissolving a tin compound and a rare earth compound in a solvent to prepare a precursor solution, and dipping the sample; and drying the sample, heating in a reactor, continuously roasting under the condition of introducing the pretreatment gas and the pretreatment auxiliary agent, introducing the inert atmosphere, and cooling to obtain the target catalyst. The catalyst has excellent activity, selectivity and stability when being used in a reaction for preparing epoxy chloropropane through epoxidation of 3-chloropropene.

Description

Technical Field

[0001] The present invention belongs to the field of catalysts, and particularly relates to a catalyst for catalytic oxidation of 3-chloropropene to epichlorohydrin with hydrogen peroxide. Background Art

[0002] Epichlorohydrin (ECH) is an important organic intermediate, mainly used in the production of epoxy resins, glycerol, chlorohydrin rubber and other derivatives, and can also be used as a solvent, plasticizer, flame retardant and surfactant, etc. It is an important organic chemical raw material and an important intermediate in petrochemical industry, with wide applications.

[0003] Currently, the mainstream production processes of epichlorohydrin include the chlorohydrin method, the glycerol method and the hydrogen peroxide oxidation method. The chlorohydrin method uses propylene as the main raw material, and the main steps include high-temperature chlorination of propylene to prepare chloropropene, hypochlorination of chloropropene to generate dichloropropanol, and saponification of dichloropropanol to synthesize epichlorohydrin. The equipment corrosion caused by the technical raw material chlorine is serious, the material requirements of the reactor are high, a large amount of sewage containing calcium chloride and organic chlorides is generated in the production process, and the treatment cost is high. Due to environmental protection problems, new construction is no longer approved in China. The glycerol method uses glycerol as the main raw material, and the main steps include chlorination of glycerol to generate dichloropropanol and cyclization of dichloropropanol to generate epichlorohydrin. This process has high energy consumption, low equipment utilization rate, depends on the supply of the main raw material glycerol, and inevitably generates saponification wastewater. The main process of the hydrogen peroxide method is divided into two steps: high-temperature chlorination of propylene to generate chloropropene and direct epoxidation of chloropropene to generate epichlorohydrin. This process has a simple production process, less pollution, and has the advantages of high selectivity, green environmental protection and relatively safe process. The process of high-temperature chlorination of propylene to produce chloropropene is an industrialized mature process, so the core of this technical route is the epoxidation step of chloropropene.

[0004] The oxidation of 3-chloropropene by hydrogen peroxide is an exothermic reaction with a fast reaction rate and a large amount of heat released. If the heat cannot be removed in time, it will exacerbate side reactions such as the polymerization of chloropropene and the ring-opening etherification of epichlorohydrin, resulting in problems such as poor product selectivity and catalyst carbon deposition deactivation. Therefore, the development of an efficient catalyst is the key to the reaction. Currently, the two most studied types of catalysts are heteropolyacid salts and titanium silicalite molecular sieve catalysts. Heteropolyacid catalysts (Patents CN 113004226 B, CN103159703B) require a phase transfer process, with high unit consumption, difficult recovery, and serious corrosion. Titanium silicalite molecular sieve catalysts are the most widely studied catalysts for the oxidation of 3-chloropropene by hydrogen peroxide to produce epichlorohydrin, with advantages such as high activity and easy separation and recovery. However, titanium silicalite has poor thermal conductivity, and the heat released by the reaction is difficult to transfer in time, leading to side reactions such as the polymerization of 3-chloropropene and the ring-opening of epichlorohydrin; moreover, titanium silicalite has a well-developed microporous pore structure, and the active sites are mainly in the microporous channels. The polymers generated by side reactions are likely to block the channels, resulting in catalyst deactivation. Patent CN114904572A reported a titanium silicalite molecular sieve catalyst containing hierarchical pores, which reduces catalyst deactivation caused by pore blockage due to product polymerization by constructing micropores and mesopores. Patent CN112408414B reported a rice flake-shaped hierarchical pore core-shell structure TS-1 molecular sieve, which eliminates the internal diffusion limitation problem existing in the pores of traditional particulate titanium silicalite molecular sieves and reduces the surface acidity of conventional TS-1 molecular sieves by constructing a hierarchical pore structure and a pure silica molecular sieve Silicalite-1 shell layer, inhibiting the formation of ring-opening by-products.

[0005] Using a material with high thermal conductivity as a carrier helps to remove the reaction heat in time and reduce the problems of many side reactions and safety issues caused by heat accumulation. Commonly used carriers include silicon carbide, silicon nitride, cordierite, etc. The surface properties of such materials are stable, with a small specific surface area, and it is difficult for the active component to be directly and stably supported on the surface of the carrier. Currently, the commonly used method is to directly coat the surface of the carrier using the viscosity of the active component precursor solution, or to pre-coat a second coating with a high specific surface area on the surface of the carrier, and form a strong interaction between the active component or the second coating and the carrier during high-temperature calcination. However, there is still a problem of active component shedding due to weak interaction under harsh reaction conditions.

[0006] In summary, currently, the catalysts for the catalytic oxidation of 3-chloropropene by hydrogen peroxide to produce epichlorohydrin still have problems such as poor strength, activity, and stability that urgently need to be solved.

[0007] Technical Solution

[0008] One of the objectives of the present invention is to provide a catalyst for the catalytic oxidation of 3-chloropropene by hydrogen peroxide to produce epichlorohydrin, which has the characteristics of excellent strength, activity, selectivity, and stability.

[0009] To achieve the above-mentioned invention object, the present invention adopts the following technical solutions:

[0010] A preparation method of a catalyst for catalytic oxidation of 3-chloropropene with hydrogen peroxide to produce epichlorohydrin, the preparation method comprising the following steps:

[0011] S1: Placing silicon carbide in a reactor, heating it up, and calcining it under the conditions of introducing a pretreatment gas, a pretreatment auxiliary agent, and a reaction gas mixture;

[0012] S2: Stopping the introduction of the reaction gas mixture, and continuing to calcine it under the conditions of introducing the pretreatment gas and the pretreatment auxiliary agent;

[0013] S3: Introducing an inert atmosphere, cooling down, and taking out the calcined sample;

[0014] S4: Dissolving a tin compound and a rare earth compound in a solvent to prepare a precursor solution, and impregnating the sample of S3;

[0015] S5: Drying the sample of S4, placing it in a reactor for heating, and continuing to calcine it under the conditions of introducing the pretreatment gas and the pretreatment auxiliary agent, introducing an inert atmosphere, and cooling down to obtain the target catalyst.

[0016] In the present invention, foam-like monolithic silicon carbide with good thermal conductivity and high strength is used as the carrier. By simultaneously introducing the pretreatment gas, the pretreatment auxiliary agent, and the Ti source into the reactor, after the pretreatment gas etches the surface of SiC to form defects under the synergistic effect of the pretreatment auxiliary agent, the Ti source can react in time to form Ti-O-Si bonds with the surface defects. The pretreatment conditions are mild and do not require special conditions such as plasma and laser. The implementation method can transfer the reaction heat from the active sites in time, reduce side reactions such as polymerization and etherification caused by too high reaction hot spot temperature, and improve the selectivity and catalyst life; by loading titanium, silicon, and rare earth metal elements on the surface of the carrier to construct active sites, the microporous pore structure is reduced, and the catalyst deactivation caused by pore blockage is reduced.

[0017] The prepared catalyst has good thermal conductivity and mass transfer performance, and has excellent activity, selectivity, and stability.

[0018] In one embodiment of the present invention, the silicon carbide described in S1 is silicon carbide powder and / or sponge-like monolithic silicon carbide.

[0019] In one embodiment of the present invention, the temperature of the heating up described in S1 is 300-1200 °C.

[0020] In one embodiment of the present invention, the pretreatment gas described in S1 is a fluoride gas, preferably one or more of SF6, XeF2, and CF4.

[0021] In one embodiment of the present invention, the pretreatment auxiliary agent described in S1 is AsH3 and / or PH3.

[0022] In one embodiment of the present invention, the reaction gas mixture in S1 is a mixture of titanium tetrachloride and oxygen; preferably, the molar ratio of the pretreatment gas, pretreatment aid, titanium tetrachloride, and oxygen fed in S1 is (1 - 4):(0.9 - 1.1):(0.9 - 1.1):(0.9 - 1.1).

[0023] In one embodiment of the present invention, the total rate of feeding various substances in S1 is 0.1 - 10 L / min.

[0024] In one embodiment of the present invention, the time for feeding various substances in S1 is 1 - 10 h.

[0025] In one embodiment of the present invention, the temperature of the calcination in S2 is 300 - 1200 °C.

[0026] In one embodiment of the present invention, the time for feeding various substances in S2 is 1 - 10 h.

[0027] In one embodiment of the present invention, the inert atmosphere in S3 is one or more of nitrogen, argon, and helium; preferably, the feeding rate of the inert atmosphere is 0.1 - 10 L / min.

[0028] In one embodiment of the present invention, the temperature in S3 is cooled to below 50 °C.

[0029] In one embodiment of the present invention, the tin compound in S4 is SnCl4 and / or SnCl2.

[0030] In one embodiment of the present invention, the rare earth compound in S4 is a rare earth metal salt, preferably one or more of La salt, Ce salt, and Sm salt; preferably, the mass ratio of the tin compound to the rare earth compound is 1:2 - 2:1.

[0031] In one embodiment of the present invention, the solvent in S4 is an organic solvent, preferably one or more of methanol, ethanol, acetone, benzene, toluene, and DMF; preferably, the total mass concentration of the tin compound and the rare earth compound in the precursor solution is 1 - 10%.

[0032] In one embodiment of the present invention, the mass ratio of the precursor solution in S4 to the sample in S3 is (5 - 20):1.

[0033] In one embodiment of the present invention, the soaking time in S4 is 1 - 10 h, and the temperature is 20 - 50 °C.

[0034] In one embodiment of the present invention, the temperature of the drying in S5 is 50 °C to 120 °C, and the drying time is 5 h to 20 h.

[0035] In one embodiment of the present invention, the heating temperature of S5 is 300 - 1200 °C, and the time is 1 h to 10 h.

[0036] In one embodiment of the present invention, the pretreatment gas in S5 is a fluoride gas, preferably one or more of SF6, XeF2, and CF4.

[0037] In one embodiment of the present invention, the pretreatment aid in S5 is AsH3 and / or PH3.

[0038] In one embodiment of the present invention, the mass ratio of the pretreatment gas to the pretreatment aid fed in S5 is (1 - 4):(0.9 - 1.1).

[0039] In one embodiment of the present invention, the total feeding rate of each substance in S5 is 0.1 - 10 L / min.

[0040] In one embodiment of the present invention, the continuous calcination time of S5 is 10 min - 5 h.

[0041] In one embodiment of the present invention, the inert atmosphere in S5 is one or more of nitrogen, argon, and helium; preferably, the feeding rate of the inert atmosphere is 0.1 - 10 L / min.

[0042] In one embodiment of the present invention, S5 is cooled to below 50 °C.

[0043] Another object of the present invention is to provide a catalyst for catalytically oxidizing 3 - chloropropene with hydrogen peroxide to produce epichlorohydrin.

[0044] A catalyst for catalytically oxidizing 3 - chloropropene with hydrogen peroxide to produce epichlorohydrin, wherein the catalyst is the catalyst prepared by the above - mentioned preparation method, and the catalyst comprises the following components, based on the total mass of the catalyst:

[0045] SiC: 74.0 - 85.0%;

[0046] TiO2: 10 - 25.0%;

[0047] SnO2: 0.5 - 3.0%;

[0048] Rare earth metal oxide: 0.5 - 3.0%.

[0049] In one embodiment of the present invention, the rare earth metal oxide comprises one or more of La2O3, CeO2, and Sm2O3.

[0050] Another object of the present invention is to provide a use of the catalyst.

[0051] Use of a catalyst, wherein the catalyst is the catalyst prepared by the above preparation method or the above catalyst, and the catalyst is used for catalyzing the oxidation of 3-chloropropene with hydrogen peroxide to produce epichlorohydrin.

[0052] Another object of the present invention is to provide a method for preparing epichlorohydrin by epoxidation of 3-chloropropene.

[0053] A method for preparing epichlorohydrin by epoxidation of 3-chloropropene, wherein the method uses the catalyst prepared by the above preparation method, or uses the above catalyst, or is the catalyst described in the above use, and the preparation method catalyzes the oxidation of 3-chloropropene with hydrogen peroxide to produce epichlorohydrin, and the reaction temperature is 20-60 °C.

[0054] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0055] (1) The pretreatment conditions are mild, and no special conditions such as plasma and laser are required.

[0056] (2) Active sites are constructed, the microporous channel structure is reduced, and the deactivation of the catalyst caused by pore blockage is reduced.

[0057] (3) 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 embodiments

[0058] The following examples further illustrate the technical solutions provided by the present invention, but the present invention is not limited to the listed examples, and also includes any other known changes within the scope of the rights of the present invention.

[0059] Main raw material information

[0060]

[0061]

[0062] Main equipment information

[0063] Equipment Name Manufacturer Model Vacuum Tube Furnace Tianjin Zhonghuan SK-B06123K-2 Fixed Bed Reactor Yantai Keli YTKL-2201 Gas Chromatograph Agilent GC-7890

[0064] Analysis and characterization methods

[0065] In the 3-chloropropene oxidation reaction to produce epichlorohydrin mentioned in the present invention, the conversion rate of hydrogen peroxide is analyzed by titration. The brand model of the titrator used is Metrohm 905 Titrando. Sodium thiosulfate solution is used to titrate hydrogen peroxide, and the concentration of hydrogen peroxide is measured. The conversion rate of hydrogen peroxide is calculated based on the concentration of hydrogen peroxide. The calculation formula is as follows:

[0066]

[0067] The selectivity of epichlorohydrin is analyzed by gas chromatography. The brand model of the gas chromatograph used is Agilent 7820A. The correction area normalization method is used to calculate the selectivity of different products.

[0068] Example 1

[0069] S1: Place 100 g of silicon carbide in a tubular reactor and heat it to 1000 °C under a nitrogen atmosphere; introduce 100 ml / min of CF4, 90 ml / min of PH3, 90 ml / min of titanium tetrachloride gas, and 90 ml / min of oxygen into the tubular reactor, and the feeding time is 2 h;

[0070] S2: Close the inlets of TiCl4 and O2, and continue to introduce CF4 and PH3 for 2 h. The calcination temperature is the same as that in S1.

[0071] S3: After the operation of S2 is completed, introduce nitrogen at 1 L / min into the tubular reactor and start to cool down. After the temperature drops to 40 °C, take out the calcined sample in the tubular reactor;

[0072] S4: Weigh 1.6 g of stannous chloride and 3.2 g of cerium nitrate and dissolve them in 200 g of ethanol to prepare a precursor solution; weigh 40 g of the sample taken out in S3 and soak it in 200 g of the precursor solution, and soak it at 20 °C for 10 h;

[0073] S5: Dry the impregnated sample in S4 in an oven at a drying temperature of 120 °C for 20 h; place the dried sample in a tubular reactor and heat it to 1000 °C under a nitrogen atmosphere of 1 L / min and calcine it for 10 h; when the calcination temperature reaches 1000 °C, introduce 100 ml / min of CF4 and 90 ml / min of PH3 into the reaction tube for 1 h; after the calcination is completed, cool down to 40 °C to obtain the target catalyst. In this target catalyst, the mass fraction of SiC is 84.9%, the mass fraction of TiO2 is 14.1%, the mass fraction of SnO2 is 0.5%, and the mass fraction of rare earth metal oxide is 0.5%.

[0074] Example 2

[0075] S1: Place 100 g of silicon carbide in a tubular reactor, heat it to 1000 °C under a nitrogen atmosphere; introduce 100 ml / min of SF6, 90 ml / min of PH3, 90 ml / min of titanium tetrachloride gas, and 90 ml / min of oxygen into the tubular reactor, and the feeding time is 2 h;

[0076] S2: Close the inlets of TiCl4 and O2, and continue to introduce SF6 and PH3 for 2 h, and the roasting temperature is the same as that in S1.

[0077] S3: After the operation of S2 is completed, introduce nitrogen at 1 L / min into the tubular reactor and start to cool down. After the temperature drops to 40 °C, take out the roasted sample in the tubular reactor;

[0078] S4: Weigh 1.6 g of stannous chloride and 3.2 g of cerium nitrate, dissolve them in 200 g of ethanol to prepare a precursor solution; weigh 40 g of the sample taken out in S3 and soak it in 200 g of the precursor solution, and soak it at 20 °C for 10 h;

[0079] S5: Dry the impregnated sample in S4 in an oven at a drying temperature of 120 °C and a drying time of 20 h; place the dried sample in a tubular reactor, heat it to 1000 °C under a nitrogen atmosphere of 1 L / min, and roast it for 10 h; when the roasting temperature reaches 1000 °C, introduce 100 ml / min of SF6 and 90 ml / min of PH3 into the reaction tube, and the introduction time is 1 h; after roasting, cool down to 40 °C to obtain the target catalyst. In this target catalyst, the mass fraction of SiC is 85.0%, the mass fraction of TiO2 is 14.0%, the mass fraction of SnO2 is 0.5%, and the mass fraction of rare earth metal oxide is 0.5%.

[0080] Example 3

[0081] S1: Place 100 g of silicon carbide in a tubular reactor, heat it to 1000 °C under a nitrogen atmosphere; introduce 100 ml / min of XeF6, 90 ml / min of PH3, 90 ml / min of titanium tetrachloride gas, and 90 ml / min of oxygen into the tubular reactor, and the feeding time is 2 h;

[0082] S2: Close the inlets of TiCl4 and O2, and continue to introduce XeF6 and PH3 for 2 h, and the roasting temperature is the same as that in S1.

[0083] S3: After the operation of S2 is completed, introduce nitrogen at 1 L / min into the tubular reactor and start to cool down. After the temperature drops to 40 °C, take out the roasted sample in the tubular reactor;

[0084] S4: Weigh 1.6 g of stannous chloride and 3.2 g of cerium nitrate, dissolve them in 200 g of ethanol to prepare a precursor solution; weigh 40 g of the sample taken out in S3, soak it in 200 g of the precursor solution, and soak it at 20 °C for 10 h;

[0085] S5: Dry the sample impregnated in S4 in an oven at a drying temperature of 120 °C and a drying time of 20 h; place the dried sample in a tubular reactor, heat it to 1000 °C under a nitrogen atmosphere of 1 L / min, and calcine it for 5 h; when the calcination temperature reaches 1000 °C, introduce 100 ml / min of XeF6 and 90 ml / min of PH3 into the reaction tube, and the introduction time is 10 h; after the calcination is completed, cool it to 40 °C to obtain the target catalyst. In this target catalyst, the mass fraction of SiC is 84.8%, the mass fraction of TiO2 is 14.2%, the mass fraction of SnO2 is 0.5%, and the mass fraction of rare earth metal oxide is 0.5%.

[0086] Example 4

[0087] S1: Place 100 g of silicon carbide in a tubular reactor and heat it to 1000 °C under a nitrogen atmosphere; introduce 100 ml / min of CF4, 90 ml / min of AsH3, 90 ml / min of titanium tetrachloride gas and 90 ml / min of oxygen into the tubular reactor, and the feeding time is 2 h;

[0088] S2: Close the inlets of TiCl4 and O2, continue to introduce CF4 and AsH3 for 2 h, and the calcination temperature is the same as that in S1.

[0089] S3: After the operation of S2 is completed, introduce 1 L / min of nitrogen into the tubular reactor and start to cool down. After the temperature drops to 40 °C, take out the sample calcined in the tubular reactor;

[0090] S4: Weigh 1.6 g of stannous chloride and 3.2 g of cerium nitrate, dissolve them in 200 g of ethanol to prepare a precursor solution; weigh 40 g of the sample taken out in S3, soak it in 200 g of the precursor solution, and soak it at 20 °C for 10 h;

[0091] S5: Dry the impregnated sample in step S4 in an oven at a drying temperature of 120 °C for 20 h. Place the dried sample in a tubular reactor and heat it to 1000 °C under a nitrogen atmosphere of 1 L / min, and calcine it for 10 h. After the calcination temperature reaches 1000 °C, introduce 100 ml / min of CF4 and 90 ml / min of AsH3 into the reaction tube for 1 h. After the calcination is completed, cool it to 40 °C to obtain the target catalyst. In this target catalyst, the mass fraction of SiC is 84.9%, the mass fraction of TiO2 is 14.1%, the mass fraction of SnO2 is 0.5%, and the mass fraction of rare earth metal oxide is 0.5%.

[0092] Example 5

[0093] S1: Place 100 g of silicon carbide in a tubular reactor and heat it to 1000 °C under a nitrogen atmosphere. Introduce 100 ml / min of CF4, 90 ml / min of PH3, 90 ml / min of titanium tetrachloride gas, and 90 ml / min of oxygen into the tubular reactor for 8 h.

[0094] S2: Close the inlets of TiCl4 and O2, and continue to introduce CF4 and PH3 for 2 h at the same calcination temperature as in S1.

[0095] S3: After the operation in S2 is completed, introduce 1 L / min of nitrogen into the tubular reactor and start to cool it. After the temperature drops to 40 °C, take out the calcined sample in the tubular reactor.

[0096] S4: Weigh 1.6 g of stannous chloride and 3.2 g of cerium nitrate, dissolve them in 200 g of ethanol to prepare a precursor solution. Weigh 40 g of the sample taken out in S3 and soak it in 200 g of the precursor solution at 20 °C for 10 h.

[0097] S5: Dry the impregnated sample in step S4 in an oven at a drying temperature of 120 °C for 20 h. Place the dried sample in a tubular reactor and heat it to 1000 °C under a nitrogen atmosphere of 1 L / min, and calcine it for 10 h. After the calcination temperature reaches 1000 °C, introduce 100 ml / min of CF4 and 90 ml / min of PH3 into the reaction tube for 1 h. After the calcination is completed, cool it to 40 °C to obtain the target catalyst. In this target catalyst, the mass fraction of SiC is 80.1%, the mass fraction of TiO2 is 18.9%, the mass fraction of SnO2 is 0.5%, and the mass fraction of rare earth metal oxide is 0.5%.

[0098] Example 6

[0099] S1: Place 100 g of silicon carbide in a tubular reactor, heat it to 1000 °C under a nitrogen atmosphere; introduce 100 ml / min of CF4, 90 ml / min of PH3, 100 ml / min of titanium tetrachloride gas, and 100 ml / min of oxygen into the tubular reactor, and the feeding time is 2 h;

[0100] S2: Close the inlets of TiCl4 and O2, and continue to introduce CF4 and PH3 for 8 h, and the calcination temperature is the same as that in S1.

[0101] S3: After the operation of S2 is completed, introduce nitrogen at 1 L / min into the tubular reactor, and start to cool down. After the temperature drops to 40 °C, take out the calcined sample in the tubular reactor;

[0102] S4: Weigh 1.6 g of stannous chloride and 3.2 g of cerium nitrate, dissolve them in 200 g of ethanol to prepare a precursor solution; weigh 40 g of the sample taken out in S3 and soak it in 200 g of the precursor solution, and soak it at 20 °C for 10 h;

[0103] S5: Dry the sample impregnated in S4 in an oven at a drying temperature of 120 °C and a drying time of 20 h; place the dried sample in a tubular reactor, heat it to 1000 °C under a nitrogen atmosphere of 1 L / min, and calcine it for 10 h; when the calcination temperature rises to 1000 °C, introduce 100 ml / min of CF4 and 90 ml / min of PH3 into the reaction tube, and the introduction time is 1 h; after the calcination is completed, cool down to 40 °C to obtain the target catalyst. In this target catalyst, the mass fraction of SiC is 85.0%, the mass fraction of TiO2 is 14.0%, the mass fraction of SnO2 is 0.5%, and the mass fraction of rare earth metal oxide is 0.5%.

[0104] Example 7

[0105] S1: Place 100 g of silicon carbide in a tubular reactor, heat it to 1000 °C under a nitrogen atmosphere; introduce 400 ml / min of CF4, 110 ml / min of PH3, 110 ml / min of titanium tetrachloride gas, and 110 ml / min of oxygen into the tubular reactor, and the feeding time is 2 h;

[0106] S2: Close the inlets of TiCl4 and O2, and continue to introduce SF6 and PH3 for 2 h, and the calcination temperature is the same as that in S1.

[0107] S3: After the operation of S2 is completed, introduce nitrogen at 1 L / min into the tubular reactor, and start to cool down. After the temperature drops to 40 °C, take out the calcined sample in the tubular reactor;

[0108] S4: Weigh 1.6 g of stannous chloride and 3.2 g of cerium nitrate, dissolve them in 200 g of ethanol to prepare a precursor solution; weigh 40 g of the sample taken out in S3, soak it in 200 g of the precursor solution, and soak it at 20 °C for 10 h;

[0109] S5: Dry the sample impregnated in S4 in an oven at a drying temperature of 120 °C and a drying time of 20 h; place the dried sample in a tubular reactor, heat it to 1000 °C under a nitrogen atmosphere of 1 L / min, and calcine it for 10 h; when the calcination temperature reaches 1000 °C, introduce 200 ml / min of CF4 and 100 ml / min of PH3 into the reaction tube for 1 h; after the calcination is completed, cool it to 40 °C to obtain the target catalyst. In this target catalyst, the mass fraction of SiC is 83.0%, the mass fraction of TiO2 is 16.0%, the mass fraction of SnO2 is 0.5%, and the mass fraction of rare earth metal oxide is 0.5%.

[0110] Example 8

[0111] S1: Place 100 g of silicon carbide in a tubular reactor and heat it to 1000 °C under a nitrogen atmosphere; introduce 2.5 L / min of CF4, 2.5 L / min of PH3, 2.5 L / min of titanium tetrachloride gas and 2.5 L / min of oxygen into the tubular reactor, and the feeding time is 2 h;

[0112] S2: Close the inlets of TiCl4 and O2, and continue to introduce SF6 and PH3 for 2 h, and the calcination temperature is the same as that in S1.

[0113] S3: After the operation of S2 is completed, introduce 1 L / min of nitrogen into the tubular reactor and start to cool down. After the temperature drops to 40 °C, take out the sample calcined in the tubular reactor;

[0114] S4: Weigh 1.6 g of stannous chloride and 3.2 g of cerium nitrate, dissolve them in 200 g of ethanol to prepare a precursor solution; weigh 40 g of the sample taken out in S3, soak it in 200 g of the precursor solution, and soak it at 20 °C for 10 h;

[0115] S5: Dry the impregnated sample in S4 in an oven at a drying temperature of 120 °C for a drying time of 20 h; place the dried sample in a tubular reactor, heat it to 1000 °C under a nitrogen atmosphere of 1 L / min, and calcine for 10 h; after the calcination temperature reaches 1000 °C, introduce 200 ml / min of CF4 and 100 ml / min of PH3 into the reaction tube for 1 h; after the calcination is completed, cool it to 40 °C to obtain the target catalyst. In this target catalyst, the mass fraction of SiC is 74.0%, the mass fraction of TiO2 is 25.0%, the mass fraction of SnO2 is 0.5%, and the mass fraction of rare earth metal oxide is 0.5%.

[0116] Example 9

[0117] S1: Place 100 g of silicon carbide in a tubular reactor and heat it to 300 °C under a nitrogen atmosphere; introduce 100 ml / min of CF4, 90 ml / min of PH3, 90 ml / min of titanium tetrachloride gas, and 90 ml / min of oxygen into the tubular reactor for a feeding time of 2 h;

[0118] S2: Close the inlets of TiCl4 and O2, and continue to introduce CF4 and PH3 for 2 h, with the calcination temperature the same as in S1.

[0119] S3: After the operation in S2 is completed, introduce 1 L / min of nitrogen into the tubular reactor and start to cool it. After the temperature drops to 40 °C, take out the calcined sample in the tubular reactor;

[0120] S4: Weigh 1.6 g of stannous chloride and 3.2 g of cerium nitrate, dissolve them in 200 g of ethanol to prepare a precursor solution; weigh 40 g of the sample taken out in S3 and soak it in 200 g of the precursor solution at 20 °C for 10 h;

[0121] S5: Dry the impregnated sample in S4 in an oven at a drying temperature of 120 °C for a drying time of 20 h; place the dried sample in a tubular reactor, heat it to 300 °C under a nitrogen atmosphere of 1 L / min, and calcine for 10 h; after the calcination temperature reaches 300 °C, introduce 200 ml / min of CF4 and 100 ml / min of PH3 into the reaction tube for 1 h; after the calcination is completed, cool it to 40 °C to obtain the target catalyst. In this target catalyst, the mass fraction of SiC is 85.0%, the mass fraction of TiO2 is 14.0%, the mass fraction of SnO2 is 0.5%, and the mass fraction of rare earth metal oxide is 0.5%.

[0122] Example 10

[0123] S1: Place 100 g of silicon carbide in a tubular reactor and heat it to 1000 °C under a nitrogen atmosphere. Introduce 100 ml / min of CF4, 90 ml / min of PH3, 90 ml / min of titanium tetrachloride gas, and 90 ml / min of oxygen into the tubular reactor, and the feeding time is 2 h;

[0124] S2: Close the inlets of TiCl4 and O2, and continue to introduce SF6 and PH3 for 2 h. The calcination temperature is the same as that in S1.

[0125] S3: After the operation in S2 is completed, introduce nitrogen at 1 L / min into the tubular reactor and start to cool down. After the temperature drops to 40 °C, take out the calcined sample in the tubular reactor;

[0126] S4: Weigh 6.4 g of stannous chloride and 3.2 g of cerium nitrate, dissolve them in 200 g of ethanol to prepare a precursor solution. Weigh 40 g of the sample taken out in S3 and soak it in 200 g of the precursor solution, and soak it at 20 °C for 10 h;

[0127] S5: Dry the sample impregnated in S4 in an oven at a drying temperature of 120 °C and a drying time of 20 h. Place the dried sample in a tubular reactor, heat it to 1000 °C under a nitrogen atmosphere of 1 L / min, and calcine it for 10 h. When the calcination temperature reaches 1000 °C, introduce 100 ml / min of CF4 and 90 ml / min of PH3 into the reaction tube for 1 h. After the calcination is completed, cool it down to 40 °C to obtain the target catalyst. In this target catalyst, the mass fraction of SiC is 82.1%, the mass fraction of TiO2 is 13.0%, the mass fraction of SnO2 is 3.0%, and the mass fraction of rare earth metal oxide is 1.9%.

[0128] Example 11

[0129] S1: Place 100 g of silicon carbide in a tubular reactor and heat it to 1000 °C under a nitrogen atmosphere. Introduce 100 ml / min of CF4, 90 ml / min of PH3, 90 ml / min of titanium tetrachloride gas, and 90 ml / min of oxygen into the tubular reactor, and the feeding time is 2 h;

[0130] S2: Close the inlets of TiCl4 and O2, and continue to introduce SF6 and PH3 for 2 h. The calcination temperature is the same as that in S1.

[0131] S3: After the operation in S2 is completed, introduce nitrogen at 1 L / min into the tubular reactor and start to cool down. After the temperature drops to 40 °C, take out the calcined sample in the tubular reactor;

[0132] S4: Weigh 1.6 g of stannous chloride and 3.2 g of cerium nitrate, dissolve them in 50 g of ethanol to prepare a precursor solution; weigh 40 g of the sample taken out in S3, immerse it in 200 g of the precursor solution, and soak it at 20 °C for 10 h;

[0133] S5: Dry the sample impregnated in S4 in an oven at a drying temperature of 120 °C for 20 h; place the dried sample in a tubular reactor, heat it to 1000 °C under a nitrogen atmosphere of 1 L / min, and calcine it for 10 h; when the calcination temperature reaches 1000 °C, introduce 100 ml / min of CF4 and 90 ml / min of PH3 into the reaction tube for 1 h; after the calcination is completed, cool it to 40 °C to obtain the target catalyst. In this target catalyst, the mass fraction of SiC is 84.0%, the mass fraction of TiO2 is 10.0%, the mass fraction of SnO2 is 3.0%, and the mass fraction of rare earth metal oxide is 3.0%.

[0134] Example 12

[0135] S1: Place 100 g of silicon carbide in a tubular reactor and heat it to 1000 °C under a nitrogen atmosphere; introduce 100 ml / min of CF4, 90 ml / min of PH3, 90 ml / min of titanium tetrachloride gas and 90 ml / min of oxygen into the tubular reactor, and the feeding time is 2 h;

[0136] S2: Close the inlets of TiCl4 and O2, continue to introduce CF4 and PH3 for 2 h, and the calcination temperature is the same as that in S1.

[0137] S3: After the operation in S2 is completed, introduce 1 L / min of nitrogen into the tubular reactor and start to cool down. After the temperature drops to 40 °C, take out the sample calcined in the tubular reactor;

[0138] S4: Weigh 1.6 g of stannous chloride and 3.2 g of lanthanum nitrate, dissolve them in 200 g of ethanol to prepare a precursor solution; weigh 40 g of the sample taken out in S3, immerse it in 200 g of the precursor solution, and soak it at 20 °C for 10 h;

[0139] S5: Dry the impregnated sample in step S4 in an oven at a drying temperature of 120 °C for 20 h. Place the dried sample in a tubular reactor, heat it to 1000 °C under a nitrogen atmosphere of 1 L / min, and calcine it for 10 h. After the calcination temperature reaches 1000 °C, introduce 100 ml / min of CF4 and 90 ml / min of PH3 into the reaction tube for 1 h. After the calcination is completed, cool it to 40 °C to obtain the target catalyst. In this target catalyst, the mass fraction of SiC is 85.0%, the mass fraction of TiO2 is 14.0%, the mass fraction of SnO2 is 0.5%, and the mass fraction of rare earth metal oxide is 0.5%.

[0140] Example 13

[0141] S1: Place 100 g of silicon carbide in a tubular reactor and heat it to 1000 °C under a nitrogen atmosphere. Introduce 100 ml / min of CF4, 90 ml / min of PH3, 90 ml / min of titanium tetrachloride gas, and 90 ml / min of oxygen into the tubular reactor for a feeding time of 2 h.

[0142] S2: Close the inlets of TiCl4 and O2, and continue to introduce CF4 and PH3 for 2 h at the same calcination temperature as in S1.

[0143] S3: After the operation in S2 is completed, introduce 1 L / min of nitrogen into the tubular reactor and start to cool it. After the temperature drops to 40 °C, take out the calcined sample in the tubular reactor.

[0144] S4: Weigh 1.6 g of stannous chloride and 3.2 g of cerium nitrate, dissolve them in 200 g of ethanol to prepare a precursor solution. Weigh 10 g of the sample taken out in S3 and soak it in 200 g of the precursor solution at 50 °C for 1 h.

[0145] S5: Dry the impregnated sample in step S4 in an oven at a drying temperature of 50 °C for 5 h. Place the dried sample in a tubular reactor, heat it to 1000 °C under a nitrogen atmosphere of 1 L / min, and calcine it for 1 h. After the calcination temperature reaches 1000 °C, introduce 100 ml / min of CF4 and 90 ml / min of PH3 into the reaction tube for 1 h. After the calcination is completed, cool it to 40 °C to obtain the target catalyst. In this target catalyst, the mass fraction of SiC is 83.2%, the mass fraction of TiO2 is 13.9%, the mass fraction of SnO2 is 1.4%, and the mass fraction of rare earth metal oxide is 1.5%.

[0146] Comparative Example 1

[0147] Compared with Example 1, the difference is that the etching aid PH3 is not introduced in the comparative example.

[0148] S1: Place 100 g of silicon carbide in a tubular reactor and heat it to 1000 °C under a nitrogen atmosphere. Introduce 100 ml / min of CF4, 90 ml / min of titanium tetrachloride gas, and 90 ml / min of oxygen into the tubular reactor, and the feeding time is 2 h;

[0149] S2: Close the inlets of TiCl4 and O2, and continue to introduce CF4 for 2 h. The calcination temperature is the same as that in S1.

[0150] S3: After the operation of S2 is completed, introduce nitrogen at 1 L / min into the tubular reactor and start to cool down. After the temperature drops below 50 °C, take out the calcined sample in the tubular reactor;

[0151] S4: Weigh 1.6 g of stannous chloride and 3.2 g of cerium nitrate, dissolve them in 200 g of ethanol to prepare a precursor solution; immerse the sample taken out in S3 into the precursor solution described in S5 and soak it at 30 °C for 3 h;

[0152] S5: Dry the sample impregnated in S4 in an oven at a drying temperature of 80 °C and a drying time of 5 h; place the dried sample in a tubular reactor, heat it to 1000 °C under a nitrogen atmosphere of 1 L / min, and calcine it for 5 h; when the calcination temperature reaches 1000 °C, introduce 100 ml / min of CF4 into the reaction tube for 1 h; after the calcination is completed, cool it down to below 100 °C to obtain the target catalyst.

[0153] Comparative Example 2

[0154] Compared with Example 1, the difference is that the etching gas CF4 is not introduced in the comparative example.

[0155] S1: Place 100 g of silicon carbide in a tubular reactor and heat it to 1000 °C under a nitrogen atmosphere. Introduce 90 ml / min of PH3, 90 ml / min of titanium tetrachloride gas, and 90 ml / min of oxygen into the tubular reactor, and the feeding time is 2 h;

[0156] S2: Close the inlets of TiCl4 and O2, and continue to introduce PH3 for 2 h. The calcination temperature is the same as that in S1.

[0157] S3: After the operation of S2 is completed, introduce nitrogen at 1 L / min into the tubular reactor and start to cool down. After the temperature drops below 50 °C, take out the calcined sample in the tubular reactor;

[0158] S4: Weigh 1.6 g of stannous chloride and 3.2 g of cerium nitrate, dissolve them in 200 g of ethanol to prepare a precursor solution; immerse the sample taken out in S3 into the precursor solution described in S5 and soak it at 30 °C for 3 h;

[0159] S5: Dry the impregnated sample in step S4 in an oven at a drying temperature of 80 °C for 5 h; place the dried sample in a tubular reactor, heat it to 1000 °C under a nitrogen atmosphere of 1 L / min, and calcine for 5 h; when the calcination temperature reaches 1000 °C, introduce 90 ml / min of PH3 into the reaction tube for 1 h; after the calcination is completed, cool it to below 100 °C to obtain the target catalyst.

[0160] Comparative Example 3

[0161] Compared with Example 1, the difference is that the etching gas CF4 and the etching aid PH3 are not introduced in the comparative example.

[0162] S1: Place 100 g of silicon carbide in a tubular reactor and heat it to 1000 °C under a nitrogen atmosphere; introduce 90 ml / min of titanium tetrachloride gas and 90 ml / min of oxygen into the tubular reactor for a feeding time of 2 h;

[0163] S2: Close the inlets of TiCl4 and O2, continue to calcine for 2 h, and the calcination temperature is the same as that in S1.

[0164] S3: After the operation in S2 is completed, introduce 1 L / min of nitrogen into the tubular reactor and start to cool down. After the temperature drops below 50 °C, take out the calcined sample in the tubular reactor;

[0165] S4: Weigh 1.6 g of stannous chloride and 3.2 g of cerium nitrate, dissolve them in 200 g of ethanol to prepare a precursor solution; immerse the sample taken out in S3 into the precursor solution described in S5 and soak it at 30 °C for 3 h;

[0166] S5: Dry the impregnated sample in step S4 in an oven at a drying temperature of 80 °C for 5 h; place the dried sample in a tubular reactor, heat it to 1000 °C under a nitrogen atmosphere of 1 L / min, and calcine for 5 h; after the calcination is completed, cool it to below 100 °C to obtain the target catalyst.

[0167] Application Example

[0168] 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 jacket circulating water for heat removal), 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, sample and analyze. The results are shown in the following table.

[0169] Table 1 Data table of catalyst activity evaluation for examples and comparative examples

[0170]

Claims

1. A preparation method of a catalyst for catalytic oxidation of 3-chloropropene with hydrogen peroxide to produce epichlorohydrin, characterized in that, The preparation method comprises the following steps: S1: Placing silicon carbide in a reactor and heating it up, and roasting it under the conditions of introducing a pretreatment gas, a pretreatment auxiliary agent, and a reaction gas mixture; S2: Stopping the introduction of the reaction gas mixture, and continuing to roast it under the conditions of introducing the pretreatment gas and the pretreatment auxiliary agent; S3: Introducing an inert atmosphere, cooling down, and taking out the roasted sample; S4: Dissolving a tin compound and a rare earth compound in a solvent to prepare a precursor solution, and impregnating the sample obtained in S3; S5: Drying the sample obtained in S4, placing it in a reactor and heating it, and continuing to roast it under the conditions of introducing the pretreatment gas and the pretreatment auxiliary agent, introducing an inert atmosphere, and cooling down to obtain the target catalyst.

2. The preparation method according to claim 1, wherein The silicon carbide described in S1 is silicon carbide powder and / or sponge-like monolithic silicon carbide; And / or, the temperature for heating up described in S1 is 300 - 1200 °C; And / or, the pretreatment gas described in S1 is a fluoride gas, preferably one or more of SF6, XeF2, and CF4; And / or, the pretreatment auxiliary agent described in S1 is AsH3 and / or PH3; And / or, the reaction gas mixture described in S1 is a mixture of titanium tetrachloride and oxygen; Preferably, the molar ratio of the pretreatment gas, the pretreatment auxiliary agent, the titanium-containing compound, and oxygen fed in S1 is (1 - 4):(0.9 - 1.1):(0.9 - 1.1):(0.9 - 1.1); And / or, the total rate of introducing each substance in S1 is 0.1 - 10 L / min; And / or, the time for introducing each substance in S1 is 1 - 10 h.

3. The preparation method according to claim 1, characterized in that, The temperature for roasting described in S2 is 300 - 1200 °C; And / or, the time for introducing each substance in S2 is 1 - 10 h.

4. The preparation method according to claim 1, characterized in that, The inert atmosphere described in S3 is one or more of nitrogen, argon, and helium; And / or, cooling down to below 50 °C in S3.

5. The preparation method according to claim 1, characterized in that, The tin compound described in S4 is SnCl4 and / or SnCl2; And / or, the rare earth compound described in S4 is a rare earth metal salt, preferably one or more of La salt, Ce salt, and Sm salt; Preferably, the mass ratio of the tin compound to the rare earth compound is 1:2 - 2:1; And / or, the solvent described in S4 is an organic solvent, preferably one or more of methanol, ethanol, acetone, benzene, toluene, and DMF; Preferably, the total mass concentration of the tin compound and the rare earth compound in the precursor solution is 1 - 10%; And / or, the mass ratio of the precursor solution to the sample obtained in S3 in S4 is (5 - 20):1; And / or, the soaking time in S4 is 1 - 10 h, and the temperature is 20 - 50 °C.

6. The preparation method according to claim 1, wherein, The temperature for drying described in S5 is 50 °C - 120 °C, and the drying time is 5 h - 20 h; And / or, the heating temperature in S5 is 300 - 1200 °C, and the time is 1 h - 10 h; And / or, the pretreatment gas described in S5 is a fluoride gas, preferably one or more of SF6, XeF2, and CF4; And / or, the pretreatment auxiliary agent described in S5 is AsH3 and / or PH3; Preferably, the mass ratio of the pretreatment gas to the pretreatment auxiliary agent fed in S5 is (1 - 4):(0.9 - 1.1); And / or, the total rate of introducing each substance in S5 is 0.1 - 10 L / min; And / or, the time for continuing roasting in S5 is 10 min - 5 h; And / or, the inert atmosphere in S5 is one or more of nitrogen, argon, and helium; And / or, the temperature is reduced to below 50 °C in S5.

7. A catalyst for the oxidation of allyl chloride to epichlorohydrin by hydrogen peroxide, wherein the catalyst is the catalyst prepared by the preparation method described in any one of claims 1-6, and is characterized in that The catalyst comprises the following components, based on the total mass of the catalyst: SiC: 74.0 - 85.0%; TiO2: 10 - 25.0%; SnO2: 0.5 - 3.0%; Rare earth metal oxide: 0.5 - 3.0%.

8. The catalyst according to claim 7, wherein The rare earth metal oxide comprises one or more of La2O3, CeO2, and Sm2O3.

9. Use of a catalyst, wherein the catalyst is the catalyst prepared by the preparation method according to any one of claims 1 - 6, or the catalyst according to claim 7 or 8, and the catalyst is used for catalyzing the oxidation of 3-chloropropene with hydrogen peroxide to produce epichlorohydrin.

10. A method for preparing epichlorohydrin by epoxidizing 3-chloropropene, wherein the method uses the catalyst prepared by the preparation method described in any one of claims 1-6, or the catalyst described in claim 7 or 8, or the catalyst for the use described in claim 9, and is characterized in that, The preparation method catalyzes the oxidation of 3-chloropropene with hydrogen peroxide to produce epichlorohydrin, and the reaction temperature is 20 - 60 °C.

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