Supported RuO2 catalyst as well as preparation method and application thereof

Abstract

The invention discloses a supported RuO2 catalyst as well as a preparation method and application thereof, and belongs to the technical field of catalysis. The preparation method comprises the following steps: mixing rutile titanium dioxide, alpha-aluminum oxide and methyl cellulose, adding sol, and sequentially performing extrusion molding, strip breaking, drying and roasting to obtain a carrier; the preparation method comprises the following steps: preparing a carrier, loading a ruthenium compound on the carrier to obtain an impregnated substance, drying to obtain a ruthenium-loaded compound precursor, adding the ruthenium-loaded compound precursor into an alkaline solution, adding a reducing substance under a water bath condition for reduction, carrying out vacuum drying, and oxidizing the obtained ruthenium-loaded precursor in the atmosphere of chlorine-containing gas and oxidizing gas to obtain the supported RuO2 catalyst. According to the invention, the chlorine element is introduced in the process of oxidizing reduced ruthenium to form RuO2, epitaxial growth on the surface of rutile titanium dioxide is induced to form a RuO2-xClx film, the low-temperature activity and high-temperature thermal stability of the catalyst are remarkably improved, and the catalyst is used for catalyzing hydrogen chloride oxidation to prepare chlorine.

Description

Technical Field

[0001] The present invention relates to the field of catalysts, and in particular to a supported RuO2 catalyst and a preparation method and application thereof. Background Art

[0002] As a very important basic chemical, chlorine is widely used in metallurgy, electronics, medicine, petrochemicals and other fields. However, the utilization rate of chlorine atoms in the chemical industry is low, and a large amount of byproduct HCl is produced, causing environmental pollution and waste of chlorine resources. Therefore, converting byproduct HCl into Cl2 and realizing the recycling of chlorine resources is the most effective and economical way to solve HCl emissions and recycling.

[0003] Patents CN1182717A, CN1145328A and CN101223104 A disclose that ruthenium compounds are loaded on titanium oxide, and ruthenium hydroxide is generated by air calcination or alkali is added, or reduced compounds are added to produce reduced ruthenium to prepare ruthenium oxide catalysts, but there are problems of insufficient low-temperature activity and high-temperature stability. In order to improve the performance of such catalysts and solve the problems of local overheating of the catalyst bed and sintering of ruthenium oxide during the reaction process, the relevant field reports that multiple batches of catalysts with specific pore volumes are loaded in the reactor tubes to improve the thermal conductivity of the catalyst bed and the ability to remove the heat of reaction, thereby inhibiting local overheating of the catalyst bed and extending the service life of the catalyst. Or α-alumina or high thermal conductivity inorganic ceramic materials are added to the carrier, and the impregnation liquid is treated with a surfactant to improve the dispersion of the loaded ruthenium. By improving the thermal conductivity and specific surface area of ​​the carrier, although the prepared catalyst has better thermal stability, the activity at low temperature is poor. Patents CN117920201A, CN103987455A and CN102626623A introduce SiO2 on the surface of rutile TiO2 to inhibit the sintering of ruthenium oxide to improve the thermal conductivity and thermal stability of the catalyst itself, but fail to effectively solve the problem of poor low-temperature activity of the catalyst and decreased activity during hydrogen chloride oxidation. It is still necessary to gradually increase the reaction temperature to increase the conversion rate of hydrogen chloride and solve the problem of accelerated activity decline at high temperature.

[0004] Therefore, the present invention attempts to introduce chlorine into the process of RuO2 formation in the redox state by setting a specific preparation method, thereby inducing RuO 2-x Cl x Epitaxial growth is carried out on the surface of rutile titanium dioxide, thereby improving the low-temperature activity and high-temperature thermal stability of the catalyst, solving the problem of the contradiction between the low-temperature activity and high-temperature thermal stability of ruthenium-based catalysts in the prior art. Summary of the invention

[0005] The purpose of the present invention is to solve the problem of the contradiction between low-temperature activity and high-temperature stability of the traditional calcination preparation of supported RuO2 catalysts, to provide a highly dispersed supported RuO2 catalyst and a preparation method which have both high catalyst activity at low temperature and high activity and thermal stability at high temperature, and to use the prepared supported RuO2 catalyst for catalytic oxidation of hydrogen chloride to produce chlorine.

[0006] In order to achieve the above technical objectives, the present invention provides a method for preparing a supported RuO2 catalyst, comprising the following steps:

[0007] (1) mixing rutile titanium dioxide, α-alumina and methyl cellulose to obtain a mixed powder, adding a sol, and sequentially performing extrusion molding, strip breaking, drying and calcining to obtain a carrier;

[0008] (2) loading the ruthenium compound onto the carrier to obtain an impregnated substance, drying the obtained loaded ruthenium compound precursor, adding the loaded ruthenium compound precursor into an alkaline solution, adding a reducing substance under water bath conditions until the foaming of the solution disappears, standing, filtering, washing until the filtrate is neutral, and vacuum drying to obtain the loaded ruthenium precursor;

[0009] (3) The supported ruthenium precursor is oxidized in the presence of chlorine-containing gas and oxidizing gas to obtain a supported RuO2 catalyst.

[0010] As an embodiment of the present invention, in the supported RuO2 catalyst of the present invention, the rutile titanium dioxide accounts for 40% to 70% of the total mass of the mixed powder.

[0011] As an embodiment of the present invention, the α-alumina accounts for 30 to 60% of the total mass of the mixed powder.

[0012] As an embodiment of the present invention, the mass of the methyl cellulose accounts for 2-5% of the total mass of the mixed powder.

[0013] As an embodiment of the present invention, the sol is at least one of titanium sol, silica sol or aluminum sol, wherein the mass of the sol is 5 to 30% of the total mass of the mixed powder.

[0014] As an embodiment of the present invention, the drying temperature in steps (1) and (2) is 80-150°C, and the drying time is 4-8 hours; the calcination temperature in step (1) is 500-800°C, and the calcination time is 4-8 hours; more preferably, the calcination temperature is 550-700°C.

[0015] As an embodiment of the present invention, the shape of the carrier is one of cylindrical, clover-shaped, and toothed spherical; the diameter of the carrier is 1 to 3 mm, and the length is 2 to 5 mm; the diameter and length range of particles of each shape remain consistent.

[0016] As an embodiment of the present invention, the step (2) of loading the ruthenium compound onto the carrier is to dissolve the ruthenium compound in a mixed solvent of water and alcohol, and load the ruthenium compound using an equal volume method or an excess impregnation method.

[0017] As an embodiment of the present invention, the ruthenium compound is at least one of ruthenium trichloride, ruthenium trichloride hydrate, ruthenium tribromide, ruthenium tribromide hydrate, chlororuthenate, chlororuthenate hydrate, ruthenium oxychloride, ruthenate, ruthenium ammine complex, ruthenium chloride amine complex, ruthenium bromide amine complex, ruthenium acetylacetonate, carbonyl ruthenium, and ruthenium nitrosyl complex; more preferably, the ruthenium compound is ruthenium chloride hydrate.

[0018] As an embodiment of the present invention, the reducing substance is at least one of hydrogen, hydrazine, methanol, ethanol, formaldehyde, acetic acid, NaBH4, and LiH; more preferably, the reducing substance is NaBH4.

[0019] As an embodiment of the present invention, the vacuum drying temperature in step (2) is 80 to 120° C., and the vacuum drying time is 4 to 8 hours.

[0020] As an embodiment of the present invention, the chlorine-containing gas is at least one of hydrogen chloride, chlorine, methyl chloride, dichloromethane, chloroform, and vinyl chloride; more preferably, the chlorine-containing gas is methyl chloride; liquid dichloromethane and chloroform are introduced after being vaporized, and the gas is introduced directly.

[0021] As an embodiment of the present invention, the oxidizing gas is at least one of oxygen, air and ozone; the oxidation temperature in step (3) is 300-500° C., and the oxidation time is 4-8 hours.

[0022] As an embodiment of the present invention, the volume of the chlorine-containing gas introduced in step (3) accounts for 0.1-5.0v% of the volume of air.

[0023] In the supported RuO2 catalyst of the present invention, rutile titanium dioxide accounts for 20% to 90% of the total mass of the carrier after calcination; more preferably, rutile titanium dioxide accounts for 30% to 70% of the total mass of the carrier.

[0024] In the supported RuO2 catalyst of the present invention, the mass of ruthenium accounts for 0.1 to 5.0 wt% of the total mass of the catalyst; more preferably, the mass of ruthenium accounts for 1.0 to 3.5 wt% of the total mass of the catalyst.

[0025] In the process of obtaining the supported RuO2 catalyst by oxidizing the ruthenium-supported precursor of the present invention, a certain amount of chlorine is introduced to induce epitaxial growth of RuO2 on the surface of rutile titanium dioxide. 2-x Cl xfilm, thereby improving the activity of the catalyst at low temperatures and the thermal stability at high temperatures.

[0026] The supported RuO2 catalyst prepared by the preparation method of the supported RuO2 catalyst of the present invention is used in the fixed-bed hydrogen chloride oxidation to produce chlorine. The use conditions are as follows: the catalyst is loaded into a fixed-bed reactor, oxygen and hydrogen chloride gas are introduced, the molar ratio of hydrogen chloride to oxygen is 4:1 to 1:1, and the mass space velocity of hydrogen chloride gas is 0.6 to 3.5 h -1 The reaction temperature is 280-420°C. The gas at the reactor outlet is absorbed by potassium iodide aqueous solution. The amount of chlorine generated and the amount of unreacted hydrogen chloride are determined by iodine titration and neutralization titration, thereby calculating the conversion rate of hydrogen chloride.

[0027] Technical effects of the present invention:

[0028] (1) The present invention mixes rutile titanium dioxide, α-alumina and methyl cellulose in a simple and convenient manner, adds sol to extrude strips, cuts the strips, dries and calcines to obtain a carrier, and then improves the high activity of the supported RuO2 catalyst at low temperatures and the high activity and stability at high temperatures through the combined effects of reduction and oxidation in a chlorine-containing gas atmosphere.

[0029] (2) The present invention introduces chlorine into the process of RuO2 formation in the redox state of Ru, inducing epitaxial growth on the surface of rutile titanium dioxide to form RuO 2-x Cl x The film not only improves the low-temperature activity of the catalyst but also improves the high-temperature thermal stability of the catalyst. The high-activity temperature zone extends from 280°C to above 390°C, and the hydrogen chloride conversion rate remains above 90-97%. When the temperature rises to 420°C, the hydrogen chloride conversion rate is still as high as above 85%, ensuring the thermal stability of the catalyst at high temperatures. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the described contents.

[0031] Example 1

[0032] A method for preparing a supported RuO2 catalyst comprises the following steps:

[0033] (1) Weigh 50 g of rutile titanium dioxide, 50 g of α-alumina, and 2.5 g of methyl cellulose, mix for 30 minutes, then add 20 g of titanium sol, continue kneading for 20 minutes, extrude and cut into strips to obtain small tooth balls with a diameter of 3.0 mm and a length of 3.5 mm, dry them in air at 110°C for 8 hours, and then calcine them at 600°C for 4 hours to obtain a carrier.

[0034] (2) 1.35 g of commercially available ruthenium trichloride with a Ru content of 37.0% was weighed and dissolved in a mixed solution of 10 mL of deionized water and 10 mL of ethanol, and then 49.5 g of a carrier was added. The obtained impregnated material was dried at 60° C. for 12 hours to obtain a loaded ruthenium trichloride precursor.

[0035] (3) The loaded ruthenium trichloride precursor was added to 50 mL of 1 mol / L sodium hydroxide solution, and 0.5 mol / L sodium borohydride solution was slowly added dropwise at 60° C. in a water bath until the foaming of the solution disappeared. After standing for 15 minutes, the solution was filtered and washed with deionized water until the filtrate was neutral. The loaded ruthenium precursor was dried under vacuum at 90° C. for 10 hours.

[0036] (4) Under the conditions of an air flow rate of 100 mL / min and a chloroform flow rate of 1 mL / min, the supported ruthenium precursor was placed in a tubular furnace and calcined at 350° C. for 4 hours to obtain a supported RuO 2 catalyst.

[0037] Example 2

[0038] A method for preparing a supported RuO2 catalyst comprises the following steps:

[0039] (1) Weigh 50 g of rutile titanium dioxide, 50 g of α-alumina, and 2.5 g of methyl cellulose, mix for 30 minutes, then add 30 g of silica sol, continue kneading for 20 minutes, extrude and cut into strips to obtain small tooth balls with a diameter of 3.0 mm and a length of 3.5 mm, dry at 110° C. in air for 4 hours, and then calcine at 650° C. for 4 hours to obtain a carrier.

[0040] (2) 1.35 g of commercially available ruthenium trichloride with a Ru content of 37.0% was weighed and dissolved in a mixed solution of 10 mL of deionized water and 10 mL of ethanol, and then 49.5 g of a carrier was added. The resulting impregnated material was then dried at 60° C. for 12 hours to obtain a loaded ruthenium trichloride precursor.

[0041] (3) The loaded ruthenium trichloride precursor was added to 50 mL of 1 mol / L sodium hydroxide solution, and 0.5 mol / L sodium borohydride solution was slowly added dropwise at 60° C. in a water bath until the foaming of the solution disappeared. After standing for 15 minutes, the solution was filtered and washed with deionized water until the filtrate was neutral. The loaded ruthenium precursor was dried under vacuum at 90° C. for 10 hours.

[0042] (4) Under the conditions of air flow rate of 100 mL / min and methyl chloride flow rate of 1 mL / min, the supported ruthenium precursor was placed in a tubular furnace and calcined at 350° C. for 4 hours to obtain a supported RuO 2 catalyst.

[0043] Example 3

[0044] A method for preparing a supported RuO2 catalyst comprises the following steps:

[0045] (1) Weigh 50 g of rutile titanium dioxide, 50 g of α-alumina, and 2.5 g of methyl cellulose, mix for 30 minutes, then add 27 g of aluminum sol, continue kneading for 20 minutes, extrude and cut into strips to obtain small tooth balls with a diameter of 3.0 mm and a length of 3.5 mm, dry them in air at 110° C. for 4 hours, and then calcine them at 700° C. for 4 hours to obtain a carrier.

[0046] (2) 1.35 g of commercially available ruthenium trichloride with a Ru content of 37.0% was weighed and dissolved in a mixed solution of 10 mL of deionized water and 10 mL of ethanol, and then 49.5 g of a carrier was added. The resulting impregnated material was then dried at 60° C. for 12 hours to obtain a loaded ruthenium trichloride precursor.

[0047] (3) The loaded ruthenium trichloride precursor was added to 50 mL of 1 mol / L sodium hydroxide solution, and 0.5 mol / L sodium borohydride solution was slowly added dropwise at 60° C. in a water bath until the foaming of the solution disappeared. After standing for 15 minutes, the solution was filtered and washed with deionized water until the filtrate was neutral. The loaded ruthenium precursor was dried under vacuum at 90° C. for 10 hours.

[0048] (4) Under the conditions of air flow rate of 100 mL / min and methyl chloride flow rate of 1 mL / min, the supported ruthenium precursor was placed in a tubular furnace and calcined at 350° C. for 8 hours to obtain a supported RuO 2 catalyst.

[0049] Example 4

[0050] A method for preparing a supported RuO2 catalyst comprises the following steps:

[0051] (1) Weigh 40 g of rutile titanium dioxide, 60 g of α-alumina, and 2.5 g of methyl cellulose, mix for 30 minutes, then add 18 g of titanium sol, continue kneading for 20 minutes, extrude and cut into strips to obtain small tooth balls with a diameter of 3.0 mm and a length of 3.5 mm, dry at 110° C. in air for 4 hours, and then calcine at 600° C. for 4 hours to obtain a carrier.

[0052] (2) Weigh 2.08 g of commercially available ruthenium acetylacetonate with a Ru content of 24.0% and dissolve it in a mixed solution of 10 mL of deionized water and 10 mL of ethanol, then add 49.5 g of the carrier, and then dry the obtained impregnated material at 60°C for 12 hours to obtain a supported ruthenium trichloride precursor.

[0053] (3) The loaded ruthenium trichloride precursor was added to 50 mL of 1 mol / L sodium hydroxide solution, and 0.5 mol / L sodium borohydride solution was slowly added dropwise at 60° C. in a water bath until the foaming of the solution disappeared. After standing for 15 minutes, the solution was filtered and washed with deionized water until the filtrate was neutral. The loaded ruthenium precursor was dried under vacuum at 90° C. for 10 hours.

[0054] (4) Under the conditions of an air flow rate of 200 mL / min and a chloroform flow rate of 1 mL / min, the supported ruthenium precursor was placed in a tubular furnace and calcined at 350° C. for 4 hours to obtain a supported RuO 2 catalyst.

[0055] Example 5

[0056] A method for preparing a supported RuO2 catalyst comprises the following steps:

[0057] (1) Weigh 70 g of rutile titanium dioxide, 30 g of α-alumina, and 2.5 g of methyl cellulose, mix for 30 minutes, then add 24 g of titanium sol, continue kneading for 20 minutes, extrude and cut into strips to obtain small tooth balls with a diameter of 3.0 mm and a length of 3.5 mm, dry at 110° C. in air for 4 hours, and then calcine at 600° C. for 4 hours to obtain a carrier.

[0058] (2) 1.35 g of commercially available ruthenium trichloride with a Ru content of 37.0% was weighed and dissolved in a mixed solution of 10 mL of deionized water and 10 mL of ethanol, and then 49.5 g of a carrier was added. The resulting impregnated material was then dried at 60° C. for 12 hours to obtain a loaded ruthenium trichloride precursor.

[0059] (3) The loaded ruthenium trichloride precursor was added to 50 mL of 1 mol / L sodium hydroxide solution, and 0.5 mol / L sodium borohydride solution was slowly added dropwise at 60° C. in a water bath until the foaming of the solution disappeared. After standing for 15 minutes, the solution was filtered and washed with deionized water until the filtrate was neutral. The loaded ruthenium precursor was dried under vacuum at 90° C. for 10 hours.

[0060] (4) Under the conditions of an air flow rate of 100 mL / min and a chloroform flow rate of 1 mL / min, the supported ruthenium precursor was placed in a tubular furnace and calcined at 350° C. for 4 hours to obtain a supported RuO 2 catalyst.

[0061] Example 6

[0062] A method for preparing a supported RuO2 catalyst comprises the following steps:

[0063] (1) Weigh 50 g of rutile titanium dioxide, 50 g of α-alumina, and 2.5 g of methyl cellulose, mix for 30 minutes, then add 20 g of titanium sol, continue kneading for 20 minutes, extrude and cut into strips to obtain small tooth balls with a diameter of 3.0 mm and a length of 3.5 mm, dry at 110° C. in air for 4 hours, and then calcine at 600° C. for 4 hours to obtain a carrier.

[0064] (2) 1.35 g of commercially available ruthenium trichloride with a Ru content of 37.0% was weighed and dissolved in a mixed solution of 10 mL of deionized water and 10 mL of ethanol, and then 49.5 g of a carrier was added. The resulting impregnated material was then dried at 60° C. for 12 hours to obtain a loaded ruthenium trichloride precursor.

[0065] (3) The loaded ruthenium trichloride precursor was added to 50 mL of 1 mol / L sodium hydroxide solution, and 0.5 mol / L sodium borohydride solution was slowly added dropwise at 60° C. in a water bath until the foaming of the solution disappeared. After standing for 15 minutes, the solution was filtered and washed with deionized water until the filtrate was neutral. The loaded ruthenium precursor was dried under vacuum at 90° C. for 10 hours.

[0066] (4) Under the conditions of air flow rate of 100 mL / min and methyl chloride flow rate of 5 mL / min, the supported ruthenium precursor was placed in a tubular furnace and calcined at 350° C. for 4 hours to obtain a supported RuO 2 catalyst.

[0067] Example 7

[0068] A method for preparing a supported RuO2 catalyst comprises the following steps:

[0069] (1) Weigh 50 g of rutile titanium dioxide, 50 g of α-alumina, and 2.5 g of methyl cellulose, mix for 30 minutes, then add 20 g of titanium sol, continue kneading for 20 minutes, extrude and cut into strips to obtain small tooth balls with a diameter of 3.0 mm and a length of 3.5 mm, dry at 110° C. in air for 4 hours, and then calcine at 600° C. for 4 hours to obtain a carrier.

[0070] (2) 1.35 g of commercially available ruthenium trichloride with a Ru content of 37.0% was weighed and dissolved in a mixed solution of 10 mL of deionized water and 10 mL of ethanol, and then 49.5 g of a carrier was added. The resulting impregnated material was then dried at 60° C. for 12 hours to obtain a loaded ruthenium trichloride precursor.

[0071] (3) The loaded ruthenium trichloride precursor was added to 50 mL of 1 mol / L sodium hydroxide solution, and 0.5 mol / L sodium borohydride solution was slowly added dropwise at 60° C. in a water bath until the foaming of the solution disappeared. After standing for 15 minutes, the solution was filtered and washed with deionized water until the filtrate was neutral. The loaded ruthenium precursor was dried under vacuum at 90° C. for 10 hours.

[0072] (4) Under the conditions of air flow rate of 100 mL / min and hydrogen chloride flow rate of 1 mL / min, the supported ruthenium precursor was placed in a tubular furnace and calcined at 350° C. for 5 hours to obtain a supported RuO 2 catalyst.

[0073] Example 8

[0074] A method for preparing a supported RuO2 catalyst comprises the following steps:

[0075] (1) Weigh 50 g of rutile titanium dioxide, 50 g of α-alumina, and 2.5 g of methyl cellulose, mix for 30 minutes, then add 20 g of titanium sol, continue kneading for 20 minutes, extrude broken strips to obtain small tooth balls with a diameter of 3.0 mm and a length of 3.5 mm, dry them in air at 110°C for 4 hours, and then calcine them at 600°C for 4 hours to obtain a carrier.

[0076] (2) 1.35 g of commercially available ruthenium trichloride with a Ru content of 37.0% was weighed and dissolved in a mixed solution of 10 mL of deionized water and 10 mL of ethanol, and then 49.5 g of a carrier was added. The resulting impregnated material was then dried at 60° C. for 12 hours to obtain a loaded ruthenium trichloride precursor.

[0077] (3) The loaded ruthenium trichloride precursor was added to 50 mL of 1 mol / L sodium hydroxide solution, and 0.5 mol / L sodium borohydride solution was slowly added dropwise at 60° C. in a water bath until the foaming of the solution disappeared. After standing for 15 minutes, the solution was filtered and washed with deionized water until the filtrate was neutral. The loaded ruthenium precursor was dried under vacuum at 90° C. for 10 hours.

[0078] (4) Under the conditions of air flow rate of 100 mL / min and methyl chloride flow rate of 3 mL / min, the supported ruthenium precursor was placed in a tubular furnace and calcined at 450° C. for 4 hours to obtain a supported RuO 2 catalyst.

[0079] Example 9

[0080] A method for preparing a supported RuO2 catalyst comprises the following steps:

[0081] (1) Weigh 50 g of rutile titanium dioxide, 50 g of α-alumina, and 2.5 g of methyl cellulose, mix for 30 minutes, then add 20 g of titanium sol, continue kneading for 20 minutes, extrude and cut into strips to obtain small tooth balls with a diameter of 3.0 mm and a length of 3.5 mm, dry at 110° C. in air for 4 hours, and then calcine at 600° C. for 4 hours to obtain a carrier.

[0082] (2) Weigh 2.70 g of commercially available ruthenium trichloride with a Ru content of 37.0% and dissolve it in a mixed solution of 10 mL of deionized water and 10 mL of ethanol, then add 49 g of the carrier, and then dry the obtained impregnated material at 60°C for 12 hours to obtain a loaded ruthenium trichloride precursor.

[0083] (3) The loaded ruthenium trichloride precursor was added to 50 mL of 1 mol / L sodium hydroxide solution, and 0.5 mol / L sodium borohydride solution was slowly added dropwise at 60° C. in a water bath until the foaming of the solution disappeared. After standing for 15 minutes, the solution was filtered and washed with deionized water until the filtrate was neutral. The loaded ruthenium precursor was dried under vacuum at 90° C. for 10 hours.

[0084] (4) Under the conditions of air flow rate of 100 mL / min and methyl chloride flow rate of 2 mL / min, the supported ruthenium precursor was placed in a tubular furnace and calcined at 350° C. for 4 hours to obtain a supported RuO 2 catalyst.

[0085] Example 10

[0086] A method for preparing a supported RuO2 catalyst comprises the following steps:

[0087] (1) Weigh 50 g of rutile titanium dioxide, 50 g of α-alumina, and 2.5 g of methyl cellulose, mix for 30 minutes, then add 20 g of titanium sol, continue kneading for 20 minutes, extrude and cut into strips to obtain small tooth balls with a diameter of 3.0 mm and a length of 3.5 mm, dry at 110° C. in air for 4 hours, and then calcine at 650° C. for 4 hours to obtain a carrier.

[0088] (2) 4.05 g of commercially available ruthenium trichloride with a Ru content of 37.0% was weighed and dissolved in a mixed solution of 10 mL of deionized water and 10 mL of ethanol, and then 48.5 g of a carrier was added. The resulting impregnated material was then dried at 60° C. for 12 hours to obtain a loaded ruthenium trichloride precursor.

[0089] (3) The loaded ruthenium trichloride precursor was added to 50 mL of 1 mol / L sodium hydroxide solution, and 0.5 mol / L sodium borohydride solution was slowly added dropwise at 60° C. in a water bath until the foaming of the solution disappeared. After standing for 15 minutes, the solution was filtered and washed with deionized water until the filtrate was neutral. The loaded ruthenium precursor was dried under vacuum at 90° C. for 10 hours.

[0090] (4) Under the conditions of an oxygen flow rate of 100 mL / min and a chloroform flow rate of 3 mL / min, the supported ruthenium precursor was placed in a tubular furnace and calcined at 350° C. for 4 hours to obtain a supported RuO 2 catalyst.

[0091] Embodiment 11

[0092] A method for preparing a supported RuO2 catalyst comprises the following steps:

[0093] (1) Weigh 50 g of rutile titanium dioxide, 50 g of α-alumina, and 2.5 g of methyl cellulose, mix for 30 minutes, then add 20 g of titanium sol, continue kneading for 20 minutes, extrude and form strips to obtain small tooth balls with a diameter of 3.0 mm and a length of 3.5 mm, dry them in air at 110° C. for 4 hours, and then calcine them at 600° C. for 4 hours to obtain a carrier.

[0094] (2) 1.35 g of commercially available ruthenium trichloride with a Ru content of 37.0% was weighed and dissolved in a mixed solution of 10 mL of deionized water and 10 mL of ethanol, and then 49.5 g of a carrier was added. The resulting impregnated material was then dried at 60° C. for 12 hours to obtain a loaded ruthenium trichloride precursor.

[0095] (3) The loaded ruthenium trichloride precursor was added to 50 mL of 1 mol / L sodium hydroxide solution, and 0.5 mol / L sodium borohydride solution was slowly added dropwise at 60° C. in a water bath until the foaming of the solution disappeared. After standing for 15 minutes, the solution was filtered and washed with deionized water until the filtrate was neutral. The loaded ruthenium precursor was dried under vacuum at 90° C. for 10 hours.

[0096] (4) Under the conditions of air flow rate of 100 mL / min and methyl chloride flow rate of 1 mL / min, the loaded ruthenium precursor was placed in a tube furnace and calcined at 350°C for 4 hours to obtain a loaded RuO2 catalyst. The mass space velocity of hydrogen chloride was increased to 1.4 h -1 .

[0097] Example 12

[0098] A method for preparing a supported RuO2 catalyst comprises the following steps:

[0099] (1) Weigh 50 g of rutile titanium dioxide, 50 g of α-alumina, and 2.5 g of methyl cellulose, mix for 30 minutes, then add 20 g of titanium sol, continue kneading for 20 minutes, extrude and cut into strips to obtain small tooth balls with a diameter of 3.0 mm and a length of 3.5 mm, dry at 110° C. in air for 4 hours, and then calcine at 600° C. for 4 hours to obtain a carrier.

[0100] (2) 1.35 g of commercially available ruthenium trichloride with a Ru content of 37.0% was weighed and dissolved in a mixed solution of 10 mL of deionized water and 10 mL of ethanol, and then 49.5 g of a carrier was added. The resulting impregnated material was then dried at 60° C. for 12 hours to obtain a loaded ruthenium trichloride precursor.

[0101] (3) The loaded ruthenium trichloride precursor was added to 50 mL of 1 mol / L sodium hydroxide solution, and 0.5 mol / L hydrazine hydrate solution was slowly added dropwise at 60° C. in a water bath until the foaming of the solution disappeared. After standing for 15 minutes, the solution was filtered and washed with deionized water until the filtrate was neutral. The loaded ruthenium precursor was vacuum dried at 90° C. for 10 hours.

[0102] (4) Under the conditions of air flow rate of 100 mL / min and methyl chloride flow rate of 1 mL / min, the supported ruthenium precursor was placed in a tubular furnace and calcined at 350° C. for 4 hours to obtain a supported RuO 2 catalyst.

[0103] Comparative Example 1

[0104] A method for preparing a supported RuO2 catalyst comprises the following steps:

[0105] (1) Weigh 50 g of rutile titanium dioxide, 50 g of α-alumina, and 2.5 g of methyl cellulose, mix for 30 minutes, then add 20 g of titanium sol, continue kneading for 20 minutes, extrude and form strips to obtain small tooth balls with a diameter of 3.0 mm and a length of 3.5 mm, dry them in air at 110° C. for 4 hours, and then calcine them at 600° C. for 4 hours to obtain a carrier.

[0106] (2) 1.35 g of commercially available ruthenium trichloride with a Ru content of 37.0% was weighed and dissolved in a mixed solution of 10 mL of deionized water and 10 mL of ethanol, and then 49.5 g of a carrier was added. The resulting impregnated material was then dried at 60° C. for 12 hours to obtain a loaded ruthenium trichloride precursor.

[0107] (3) Under the condition of an air flow rate of 100 mL / min, the loaded ruthenium precursor was placed in a tubular furnace and calcined at 350°C for 4 hours to obtain a loaded RuO2 catalyst.

[0108] Comparative Example 2

[0109] A method for preparing a supported RuO2 catalyst comprises the following steps:

[0110] (1) Weigh 50 g of rutile titanium dioxide, 50 g of α-alumina, and 2.5 g of methyl cellulose, mix for 30 minutes, then add 20 g of titanium aluminum sol, continue kneading for 20 minutes, extrude and cut into strips to obtain small tooth balls with a diameter of 3.0 mm and a length of 3.5 mm, dry at 110°C in air for 4 hours, and then calcine at 600°C for 4 hours to obtain a carrier.

[0111] (2) 1.35 g of commercially available ruthenium trichloride with a Ru content of 37.0% was weighed and dissolved in a mixed solution of 10 mL of deionized water and 10 mL of ethanol, and then 49.5 g of a carrier was added. The resulting impregnated material was then dried at 60° C. for 12 hours to obtain a loaded ruthenium trichloride precursor.

[0112] (3) Under the conditions of air flow rate of 100 mL / min and methyl chloride flow rate of 1 mL / min, the supported ruthenium trichloride precursor was placed in a tubular furnace and calcined at 350° C. for 4 hours to obtain a supported RuO2 catalyst.

[0113] Comparative Example 3

[0114] A method for preparing a supported RuO2 catalyst comprises the following steps:

[0115] (1) Weigh 50 g of rutile titanium dioxide, 50 g of α-alumina, and 2.5 g of methyl cellulose, mix for 30 minutes, then add 20 g of titanium sol, continue kneading for 20 minutes, extrude and cut into strips to obtain small tooth balls with a diameter of 3.0 mm and a length of 3.5 mm, dry at 110° C. in air for 4 hours, and then calcine at 600° C. for 4 hours to obtain a carrier.

[0116] (2) 1.35 g of commercially available ruthenium trichloride with a Ru content of 37.0% was weighed and dissolved in a mixed solution of 10 mL of deionized water and 10 mL of ethanol, and then 49.5 g of a carrier was added. The resulting impregnated material was then dried at 60° C. for 12 hours to obtain a loaded ruthenium trichloride precursor.

[0117] (3) The loaded ruthenium trichloride precursor was added to 50 mL of 1 mol / L sodium hydroxide solution, and 0.5 mol / L sodium borohydride solution was slowly added dropwise at 60° C. in a water bath until the foaming of the solution disappeared. The solution was allowed to stand for 15 minutes and filtered. The solution was washed with deionized water until the filtrate was neutral, and vacuum dried at 90° C. for 10 hours to obtain the loaded ruthenium precursor.

[0118] (4) Under the condition of an air flow rate of 100 mL / min, the loaded ruthenium precursor was placed in a tubular furnace and calcined at 350° C. for 4 hours to obtain a loaded RuO2 catalyst.

[0119] Comparative Example 4

[0120] A method for preparing a supported RuO2 catalyst comprises the following steps:

[0121] (1) Weigh 50 g of rutile titanium dioxide, 50 g of α-alumina, and 2.5 g of methyl cellulose, mix for 30 minutes, then add 20 g of titanium aluminum sol, continue kneading for 20 minutes, extrude and cut into strips to obtain small tooth balls with a diameter of 3.0 mm and a length of 3.5 mm, dry at 110°C in air for 4 hours, and then calcine at 600°C for 4 hours to obtain a carrier.

[0122] (2) Weigh 1.35 g of commercially available ruthenium trichloride with a Ru content of 37.0% and dissolve it in 20 mL of deionized water, then add 49.5 g of the carrier, and then dry the obtained impregnated material at 60°C for 12 hours to obtain a loaded ruthenium trichloride precursor.

[0123] (3) Under the conditions of air flow rate of 100 mL / min and methyl chloride flow rate of 1 mL / min, the supported ruthenium trichloride precursor was placed in a tubular furnace and calcined at 350° C. for 4 hours to obtain a supported RuO2 catalyst.

[0124] Comparative Example 5

[0125] A method for preparing a supported RuO2 catalyst comprises the following steps:

[0126] (1) Weigh 100 g of rutile titanium dioxide and 2.5 g of methyl cellulose, mix for 30 minutes, then add 35 g of titanium sol, continue kneading for 20 minutes, extrude and cut into strips to obtain small tooth balls with a diameter of 3.0 mm and a length of 3.5 mm, dry at 110° C. in air for 4 hours, and then calcine at 600° C. for 4 hours to obtain a carrier.

[0127] (2) 1.35 g of commercially available ruthenium trichloride with a Ru content of 37.0% was weighed and dissolved in a mixed solution of 10 mL of deionized water and 10 mL of ethanol, and then 49.5 g of a carrier was added. The resulting impregnated material was then dried at 60° C. for 12 hours to obtain a loaded ruthenium trichloride precursor.

[0128] (3) The loaded ruthenium trichloride precursor was added to 50 mL of 1 mol / L sodium hydroxide solution, and 0.5 mol / L sodium borohydride solution was slowly added dropwise at 60° C. in a water bath until the foaming of the solution disappeared. After standing for 15 minutes, the solution was filtered and washed with deionized water until the filtrate was neutral. The loaded ruthenium precursor was dried under vacuum at 90° C. for 10 hours.

[0129] (4) Under the conditions of air flow rate of 100 mL / min and methyl chloride flow rate of 1 mL / min, the supported ruthenium precursor was placed in a tubular furnace and calcined at 350° C. for 4 hours to obtain a supported RuO 2 catalyst.

[0130] Comparative Example 6

[0131] A method for preparing a supported RuO2 catalyst comprises the following steps:

[0132] (1) Weigh 50 g of rutile titanium dioxide, 50 g of α-alumina, and 2.5 g of methyl cellulose, mix for 30 minutes, then add 20 g of titanium sol, continue kneading for 20 minutes, extrude and cut into strips to obtain small tooth balls with a diameter of 3.0 mm and a length of 3.5 mm, dry at 110° C. in air for 4 hours, and then calcine at 600° C. for 4 hours to obtain a carrier.

[0133] (2) 1.35 g of commercially available ruthenium trichloride with a Ru content of 37.0% was weighed and dissolved in a mixed solution of 10 mL of deionized water and 10 mL of ethanol, and then 49.5 g of a carrier was added. The resulting impregnated material was then dried at 60° C. for 12 hours to obtain a loaded ruthenium trichloride precursor.

[0134] (3) The loaded ruthenium trichloride precursor was added to 50 mL of 1 mol / L sodium hydroxide solution, and 0.5 mol / L sodium borohydride solution was slowly added dropwise at 60° C. in a water bath until the foaming of the solution disappeared. After standing for 15 minutes, the solution was filtered and washed with deionized water until the filtrate was neutral. The loaded ruthenium precursor was dried under vacuum at 90° C. for 10 hours.

[0135] (4) Under the conditions of air flow rate of 100 mL / min and methyl chloride flow rate of 10 mL / min, the supported ruthenium precursor was placed in a tubular furnace and calcined at 350° C. for 4 hours to obtain a supported RuO 2 catalyst.

[0136] Effect example

[0137] Production of chlorine by hydrogen chloride reaction in fixed bed

[0138] The activity of the catalysts prepared in Examples 1-12 and Comparative Examples 1-6 was evaluated in a fixed bed reactor. The catalyst evaluation was performed using a fixed bed reactor with a length of 1000 mm, an inner diameter of 20 mm, and a catalyst loading of 30.0 g. Hydrogen chloride gas and oxygen were introduced under normal pressure. The mass space velocity of hydrogen chloride was 0.7 h / min. -1 The volume ratio of HCl and O2 is 2:1. During the reaction, samples are taken by absorbing the tail gas with a quantitative potassium iodide solution. The amount of Cl2 and unreacted HCl in the sample is titrated by iodometric method and acid-base titration method, respectively. The conversion rate of hydrogen chloride is calculated accordingly. The results of hydrogen chloride conversion rates of different catalysts at different temperatures are shown in Table 1.

[0139] Table 1 Hydrogen chloride conversion rate at different temperatures in different embodiments

[0140]

[0141]

[0142] As can be seen from Table 1, compared with Comparative Example 1-6, the catalyst prepared in Example 1-12 is a supported RuO2 catalyst obtained by reduction and oxidation in a chlorine-containing gas; for the same reaction temperature, the hydrogen chloride conversion rate of Example 1-12 is significantly higher than that of Comparative Example 1-6, at 280-390°C, the hydrogen chloride conversion rate is more than 90%, and the high activity temperature zone extends from 280°C to 390°C; at 420°C, the hydrogen chloride conversion rate is still as high as 85%, the maximum conversion rate decreases by ≤10%, and the thermal stability is significantly better than that of the comparative example.

[0143] According to the hydrogen chloride conversion rate of the catalysts prepared in Comparative Examples 1-3, it can be seen that when one of the three steps of reduction, chlorine-containing gas, and oxidation is missing, the conversion rate and thermal stability of hydrogen chloride are significantly reduced; More importantly, from the results of Comparative Examples 1 and 3, it can be seen that the activity of the catalyst prepared by direct calcination of the supported ruthenium trichloride precursor in air and calcination in air after reduction is significantly reduced at low temperatures and thermal stability at high temperatures. Compared with the catalyst prepared by the combined action of chlorine-containing oxidation after reduction, the conversion rate of hydrogen chloride is reduced by 20-40%. Among them, it can be seen from Comparative Examples 1 and 2 that reduction and the introduction of chlorine in the oxidation process have a common decisive effect on the low-temperature activity and high-temperature stability of the catalyst, especially the introduction of chlorine in the oxidation process, which induces epitaxial growth on the surface of rutile titanium dioxide to form RuO 2-x Cl x The film significantly improves the low-temperature activity and high-temperature thermal stability of the catalyst. As shown in Comparative Example 3, no chlorine is introduced in the oxidation step. Although the catalyst initially shows a hydrogen chloride conversion rate of 85%, as the reaction temperature increases, the hydrogen chloride conversion rate gradually decreases, and the stability shown is significantly lower than that of the embodiment.

[0144] According to the comparison between Examples 1-12 and Comparative Examples 4-6, it can be seen that in the process of preparing the supported RuO2 catalyst, the ruthenium compound needs to be loaded onto the carrier in a mixed solvent of alcohol and water; from Comparative Example 5, it can be seen that when there is no α-alumina in the carrier, the high-temperature stability of the supported RuO2 catalyst is significantly reduced; from Comparative Example 6, it can be seen that when the volume ratio of chlorine-containing gas in the oxidizing mixed gas is increased to 10%, the overall activity and thermal stability of the prepared supported RuO2 catalyst are affected, and the hydrogen chloride conversion rate is significantly reduced.

[0145] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a supported RuO2 catalyst, characterized in that: The steps include: (1) mixing rutile titanium dioxide, α-alumina and methyl cellulose to obtain a mixed powder, adding a sol, sequentially performing extrusion molding, breaking and drying, and calcining to obtain a carrier; (2) loading a ruthenium compound onto a carrier to obtain an impregnated substance, adding the obtained loaded ruthenium compound precursor to an alkaline solution after drying, adding a reducing substance under water bath conditions until the foaming of the solution disappears, standing, filtering, washing until the filtrate is neutral, and vacuum drying to obtain a loaded ruthenium precursor; (3) The supported ruthenium precursor is oxidized in the presence of chlorine-containing gas and oxidizing gas to obtain a supported RuO2 catalyst.

2. The method for preparing a supported RuO2 catalyst according to claim 1, characterized in that: The rutile titanium dioxide accounts for 40% to 70% of the total mass of the mixed powder; the α-alumina accounts for 30 to 60% of the total mass of the mixed powder; the mass of the methyl cellulose accounts for 2 to 5% of the total mass of the mixed powder; the sol is at least one of titanium sol, silica sol, and aluminum sol, wherein the mass of the sol accounts for 5 to 30% of the total mass of the mixed powder.

3. The method for preparing a supported RuO2 catalyst according to claim 1, characterized in that: The calcination temperature in step (1) is 500-800° C., and the calcination time is 4-8 hours.

4. The method for preparing a supported RuO2 catalyst according to claim 1, characterized in that: The ruthenium compound is at least one of ruthenium trichloride, ruthenium trichloride hydrate, ruthenium tribromide, ruthenium tribromide hydrate, chlororuthenate, chlororuthenate and its hydrate, ruthenium oxychloride, ruthenate, ruthenium ammine complex, ruthenium chloride amine complex, ruthenium bromide amine complex, ruthenium acetylacetonate, carbonyl ruthenium, and ruthenium nitrosyl complex; the mass of ruthenium in the loaded RuO2 accounts for 0.1 to 5.0 wt% of the total mass of the catalyst.

5. The method for preparing the supported RuO2 catalyst according to claim 1, characterized in that: The reducing substance is at least one of hydrogen, hydrazine, methanol, ethanol, formaldehyde, acetic acid, NaBH4, and LiH.

6. The method for preparing a supported RuO2 catalyst according to claim 1, characterized in that: The chlorine-containing gas is at least one of hydrogen chloride, chlorine, methyl chloride, dichloromethane, chloroform, and vinyl chloride.

7. The method for preparing a supported RuO2 catalyst according to claim 1, characterized in that: The volume ratio of the chlorine-containing gas to the oxidizing gas is 0.1-5.0:

100.

8. The method for preparing a supported RuO2 catalyst according to claim 1, characterized in that: In step (3), the oxidizing gas is at least one of oxygen, air and ozone; the oxidation temperature is 300 to 500° C., and the oxidation time is 4 to 8 hours.

9. A supported RuO2 catalyst prepared according to the method for preparing a supported RuO2 catalyst according to any one of claims 1 to 8.

10. Use of the supported RuO2 catalyst according to claim 9 in catalyzing the oxidation of hydrogen chloride to produce chlorine.

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