A manganese-based composite monatomic catalyst and method for propane low-temperature oxidation to acetone

Abstract

The application discloses a manganese-based composite monatomic catalyst and a method for propane low-temperature oxidation to prepare acetone, the manganese-based composite catalyst is characterized by taking manganese as an active component, at least one of iron, cobalt, copper and nickel as a first assistant, at least one of carbon and nitrogen as a second assistant, and at least one of aluminum oxide, cerium oxide, zinc oxide, zirconium oxide and niobium pentoxide as a carrier. The manganese-based composite monatomic catalyst is used in propane oxidation reaction with oxygen as an oxidant, and does not need to be matched with strong acid solvents, carbon monoxide and other harmful substances during use, is green and environment-friendly, can realize high-efficiency catalytic reaction under low-temperature conditions, and can obtain acetone with high selectivity, and the acetone yield can reach 45-55mmolg 催化剂 ‑1 h ‑1 The content of acetone in the liquid product can reach 65% at most, and the catalyst has excellent stability and can be stably recycled for 5 times without obvious deactivation.

Description

Technical Field

[0001] The present invention belongs to the fields of catalysis and chemical engineering, and particularly relates to a manganese-based composite single-atom catalyst and a method for producing acetone by low-temperature oxidation of propane. Background Art

[0002] Propane is a thermodynamically stable organic compound that often occurs as a by-product during the extraction of resources such as petroleum, natural gas, and shale gas. Due to its low explosive limit and easy liquefaction under pressure, propane is typically stored and transported in high-pressure tanks as liquefied petroleum gas (LPG). This carries high storage and transportation costs and significant safety risks, making it unsuitable for long-distance land transportation. With the continued development of resources such as shale gas, propane production has increased annually. However, aside from propane dehydrogenation (PDH), there are limited avenues for the industrial application of propane. Propane dehydrogenation converts propane to propylene at 500-700°C, resulting in high investment costs and requiring integration with downstream industries such as polypropylene plants that are highly dependent on water resources. Due to these specific limitations, PDH plants in my country are typically located in the southeastern coastal areas, making it difficult to access resources in major propane-producing regions such as the northwest. Therefore, developing propane utilization technologies tailored to my country's resource endowment and enabling in-situ conversion and utilization of propane resources is of great practical significance.

[0003] Using oxygen as an oxidant, converting propane into liquid oxygen-containing compounds such as acetone and propanol through an oxidation reaction, especially realizing this process at low temperatures, is an ideal approach. First, the system of this reaction process is simple and the equipment requirements are low, which is suitable for construction in inland areas of my country. Secondly, products such as acetone and propanol are liquids at room temperature and pressure. They are relatively safe and economical to store and transport, and have a wide range of uses, making them convenient for on-site use as chemical raw materials. However, propane is a thermodynamically stable low-chain alkane and usually requires high temperatures to activate. Under low temperature conditions, propane exhibits inertness in oxidation reactions, and the yield of the product is usually less than 1 mmol. 产物 g 催化剂 -1 h -1, making it difficult to meet the needs of industrial production (Science, 2014, 343(6176)1232-1237; Nature Catalysis (2023)6, 666–675; Nature Catalysis (2023)6, 1052–1061; Nature Communications, 2022, 13 5065). To address this issue, the low-temperature oxidation process of propane typically requires the use of strong acids such as fuming sulfuric acid and trifluoroacetic acid as reaction solvents (Nature Catalysis 2023, 6, 666–675, Science, 2014, 343(6176)1232-1237), or the addition of large amounts of carbon monoxide to the reaction system (J. Am. Chem. Soc. 2023, 145, 769-773). This special reaction system not only reduces the economic efficiency of the reaction process, but also raises issues such as environmental pollution and safety, making it difficult to put into industrial application. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problems existing in the above-mentioned prior art and provide a manganese-based composite single-atom catalyst with high selectivity and good stability for the low-temperature oxidation of propane to acetone.

[0005] The manganese-based composite single-atom catalyst provided by the present invention is a manganese-based composite single-atom catalyst that uses manganese as an active component, at least one of iron, cobalt, copper, and nickel as a first auxiliary agent, at least one of carbon and nitrogen elements as a second auxiliary agent, and at least one of aluminum oxide, cerium oxide, zinc oxide, zirconium oxide, and niobium pentoxide as a carrier; based on the mass of the catalyst as 100%, the content of the active component is 0.1% to 1.5%, the content of the first auxiliary agent is 0.1% to 0.5%, and the content of the second auxiliary agent is 0.5% to 1%.

[0006] The preparation method of the above-mentioned manganese-based composite single-atom catalyst is as follows: dissolve the manganese precursor, the first auxiliary agent precursor, and the second auxiliary agent precursor in deionized water, stir and heat to 60-80°C, then add the carrier thereto and continue stirring and heating until it becomes a viscous paste, take it out, cover it with plastic wrap, and then age, dry, grind, and vacuum calcinate to obtain a manganese-based composite single-atom catalyst.

[0007] Furthermore, it is preferred that the manganese precursor is any one of manganese nitrate, manganese sulfate, and manganese chloride.

[0008] Furthermore, it is preferred that the precursor of the first auxiliary agent iron is any one of ferric nitrate, ferric oxalate, and ammonium ferric citrate, the precursor of the first auxiliary agent cobalt is any one of cobalt nitrate, cobalt acetylacetonate, and cobalt oxalate, the precursor of the first auxiliary agent copper is copper nitrate or copper sulfate, and the precursor of the first auxiliary agent nickel is nickel nitrate or nickel oxalate.

[0009] Furthermore, it is preferred that the precursor of the second auxiliary carbon element is at least one of fructose, sucrose, maltose, and oxalic acid, and the precursor of the second auxiliary nitrogen element is at least one of ethylenediamine, amino acid, and dimethylimidazole.

[0010] Furthermore, in the method for preparing the manganese-based composite catalyst, it is preferred that the stirring speed is 500 to 800 r / min, and the stirring and heating time after adding the carrier is continuous for 1 to 3 hours.

[0011] Furthermore, in the method for preparing the manganese-based composite catalyst, it is preferred that the aging time is 8 to 12 hours, the drying temperature is 100 to 150° C., and the drying time is 4 to 8 hours.

[0012] Furthermore, in the method for preparing the manganese-based composite catalyst, it is preferred that the vacuum calcination temperature is 300-500° C. and the time is 1-4 h.

[0013] The present invention also provides a method for producing acetone by low-temperature oxidation of propane, which specifically comprises the following steps: adding the above-mentioned manganese-based composite single-atom catalyst and acetonitrile into a high-pressure reactor, sealing the reactor, introducing propane and oxygen in sequence, wherein the pressure of the propane is 0.3 to 0.8 MPa and the pressure of the oxygen is 0.5 to 1.5 MPa, and the reaction is stirred at 100 to 200° C. for 4 to 12 hours.

[0014] Furthermore, in the above-mentioned method for producing acetone by low-temperature oxidation of propane, the reaction is preferably stirred at 160-180° C. for 5-7 hours.

[0015] The beneficial effects of the present invention are as follows:

[0016] The catalyst of the present invention uses inexpensive manganese as the active ingredient, transition metals as additives, and is doped with carbon and nitrogen. During the catalyst preparation process, the stirring temperature is controlled to ensure sufficient contact between the precursor and the support, allowing the manganese precursor to be uniformly adsorbed on the support surface. Subsequent drying and calcination yield a manganese-based composite single-atom catalyst in which both the active ingredient and the additive are highly dispersed in the form of single atoms on the support. The catalyst of the present invention is low-cost, has a simple preparation method, and is readily suitable for large-scale industrial application.

[0017] 2. The manganese-based composite single-atom catalyst of the present invention is used in the propane oxidation reaction with oxygen as the oxidant. It can achieve high-efficiency catalytic reaction to produce acetone at low temperature conditions of 100-200°C, and the acetone yield can reach 40-55mmolg 催化剂 -1 h -1 The acetone content in the liquid product can reach up to 65%, with high selectivity for acetone. The catalyst has excellent stability and can be stably cycled 5 times without obvious deactivation.

[0018] 3. The manganese-based composite single-atom catalyst of the present invention is used to catalyze the low-temperature oxidation of propane to produce acetone. During use, no strong acidic solvents, carbon monoxide and other harmful substances need to be used, which is green and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 1 is the XRD pattern of the manganese-based composite single-atom catalyst and alumina in Examples 1, 2, and 3.

[0020] Figure 2 This is the spherical aberration corrected HAADF-STEM image of the manganese-based composite single-atom catalyst in Example 1. DETAILED DESCRIPTION

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and examples, but the protection scope of the present invention is not limited to these examples.

[0022] Example 1

[0023] The manganese-based composite single-atom catalyst of this embodiment uses manganese as an active component, iron as a first auxiliary agent, nitrogen as a second auxiliary agent, and aluminum oxide as a carrier. Based on the mass of the catalyst as 100%, the manganese content is 0.3%, the iron content is 0.3%, and the nitrogen content is 0.5%. The catalyst is prepared as follows:

[0024] Weigh 16mg of manganese nitrate, 22.12mg of ferric nitrate nine hydrate, and 10.7mg of ethylenediamine and dissolve them in 50mL of deionized water. Heat to 60℃ under stirring, add 1g of alumina powder, stir thoroughly at 60℃ for 1h, cover with plastic wrap, age for 12h, place in a drying oven at 80℃ and dry for 8 hours. Grind to fine powder, then place in a tube furnace, heat to 400℃ at a heating rate of 5℃ / min under vacuum, calcine at constant temperature for 1.5h, cool naturally to room temperature and take out to obtain a manganese-based composite single-atom catalyst. Figure 1 It can be seen that the XRD spectrum of the obtained catalyst is similar to that of alumina, indicating that no obvious metal particles are formed and the dispersion is good. Figure 2 Evenly distributed, bright and well-dispersed bright spots can be seen on the alumina support, indicating that the metal is dispersed at the atomic level on the surface of the alumina support.

[0025] 30 mg of the manganese-based composite single-atom catalyst and 28 mL of acetonitrile were placed in a 100 mL autoclave. After sealing, propane and oxygen were introduced sequentially at a propane pressure of 0.6 MPa and an oxygen pressure of 1.2 MPa, respectively. The reaction was stirred at 170°C for 6 h at a speed of 600 rpm. The liquid product was collected and filtered for quantitative analysis using a gas chromatograph-mass spectrometer. The reaction results are shown in Table 1.

[0026] Example 2

[0027] The manganese-based composite single-atom catalyst of this embodiment has manganese as an active component, iron as a first auxiliary agent, nitrogen as a second auxiliary agent, and aluminum oxide as a carrier. Based on the mass of the catalyst as 100%, the manganese content is 1%, the iron content is 0.3%, and the nitrogen content is 0.5%. The catalyst is prepared as follows:

[0028] 30.2 mg of manganese sulfate, 22.12 mg of ferric nitrate nonahydrate, and 10.7 mg of ethylenediamine were weighed and dissolved in 50 mL of deionized water. The mixture was heated to 60 ° C under stirring, and 1 g of alumina powder was added. The mixture was stirred at 60 ° C for 1 hour, covered with plastic wrap, aged for 12 hours, and placed in a drying oven at 80 ° C for 8 hours. After being taken out, it was ground into fine powder, and then placed in a tube furnace. The temperature was increased to 500 ° C at a heating rate of 5 ° C / min under vacuum conditions, and the mixture was calcined at a constant temperature for 1.5 hours. After naturally cooling to room temperature, it was taken out to obtain a manganese-based composite single-atom catalyst (see Figure 1 ).

[0029] 30 mg of the manganese-based composite single-atom catalyst and 28 mL of acetonitrile were placed in a 100 mL autoclave. After sealing, propane and oxygen were introduced sequentially at a propane pressure of 0.6 MPa and an oxygen pressure of 1.2 MPa, respectively. The reaction was stirred at 160°C for 6 h at a speed of 600 rpm. The liquid product was collected and filtered for quantitative analysis using a gas chromatograph-mass spectrometer. The reaction results are shown in Table 1.

[0030] Example 3

[0031] The manganese-based composite single-atom catalyst of this embodiment has manganese as an active component, iron as a first auxiliary agent, nitrogen and carbon as second auxiliary agents, and alumina as a carrier. Based on 100% by mass of the catalyst, the manganese content is 1.5%, the iron content is 0.3%, the nitrogen content is 0.5%, and the carbon content is 0.7%. The catalyst is prepared as follows:

[0032] 38.8 mg of manganese chloride, 22.12 mg of ferric nitrate nonahydrate, 10.7 mg of ethylenediamine, and 16.62 mg of sucrose were weighed and dissolved in 50 mL of deionized water. The mixture was heated to 60 ° C under stirring, and 1 g of alumina powder was added. The mixture was stirred at 60 ° C for 1 hour, covered with plastic wrap, aged for 12 hours, and placed in a drying oven at 80 ° C for 8 hours. After being taken out, it was ground into fine powder, and then placed in a tube furnace. The temperature was increased to 350 ° C at a heating rate of 5 ° C / min under vacuum conditions, and the mixture was calcined at a constant temperature for 1 hour. After naturally cooling to room temperature, it was taken out to obtain a manganese-based composite single-atom catalyst (see Figure 1 ).

[0033] 30 mg of the manganese-based composite single-atom catalyst and 28 mL of acetonitrile were added to a 100 mL autoclave. After sealing, propane and oxygen were introduced sequentially at a propane pressure of 0.6 MPa and an oxygen pressure of 1.2 MPa, respectively. The reaction was stirred at 175°C for 6 h at a speed of 600 rpm. The liquid product was collected, filtered, and quantitatively analyzed by gas chromatography-mass spectrometry. The reaction results are shown in Table 1.

[0034] Example 4

[0035] The manganese-based composite single-atom catalyst of this embodiment uses manganese as an active component, copper as a first auxiliary agent, nitrogen as a second auxiliary agent, and cerium oxide as a carrier. Based on the mass of the catalyst as 100%, the manganese content is 0.3%, the copper content is 0.4%, and the nitrogen content is 0.5%. The catalyst is prepared as follows:

[0036] Weigh 16 mg of manganese nitrate, 12.2 mg of copper nitrate, and 10.7 mg of ethylenediamine and dissolve them in 50 mL of deionized water. Heat to 60°C under stirring, add 1 g of cerium oxide powder, stir thoroughly at 60°C for 1 hour, cover with plastic wrap, age for 12 hours, place in a drying oven at 80°C and dry for 8 hours. After taking out, grind into fine powder, then place in a tubular furnace, heat to 400°C at a heating rate of 5°C / min under vacuum conditions, calcine at a constant temperature for 1.5 hours, cool naturally to room temperature and take out to obtain a manganese-based composite single-atom catalyst.

[0037] 30 mg of the manganese-based composite single-atom catalyst and 28 mL of acetonitrile were added to a 100 mL autoclave. After sealing, propane and oxygen were introduced sequentially at a propane pressure of 0.6 MPa and an oxygen pressure of 1.2 MPa, respectively. The reaction was stirred at 175°C for 6 h at a speed of 600 rpm. The liquid product was collected, filtered, and quantitatively analyzed by gas chromatography-mass spectrometry. The reaction results are shown in Table 1.

[0038] Example 5

[0039] The manganese-based composite single-atom catalyst of this embodiment uses manganese as an active component, cobalt and nickel as first additives, carbon as a second additive, and cerium oxide as a carrier. Based on 100% by mass of the catalyst, the manganese content is 0.4%, the cobalt content is 0.3%, the nickel content is 0.4%, and the carbon content is 0.7%. The catalyst is prepared as follows:

[0040] Weigh 16 mg of manganese nitrate, 9.6 mg of cobalt nitrate, 17.5 mg of nickel acetylacetonate, and 16.62 mg of sucrose and dissolve them in 50 mL of deionized water. Heat to 60°C under stirring, add 1 g of cerium oxide powder, stir thoroughly at 60°C for 1 hour, cover with plastic wrap, age for 12 hours, place in a drying oven at 80°C and dry for 8 hours. After taking out, grind into fine powder, then place in a tubular furnace, heat to 500°C at a heating rate of 5°C / min under vacuum conditions, calcine at constant temperature for 1 hour, cool naturally to room temperature and take out to obtain a manganese-based composite single-atom catalyst.

[0041] 30 mg of the manganese-based composite single-atom catalyst and 28 mL of acetonitrile were added to a 100 mL autoclave. After sealing, propane and oxygen were introduced sequentially at a propane pressure of 0.6 MPa and an oxygen pressure of 1.2 MPa, respectively. The reaction was stirred at 175°C for 6 h at a speed of 600 rpm. The liquid product was collected, filtered, and quantitatively analyzed by gas chromatography-mass spectrometry. The reaction results are shown in Table 1.

[0042] Example 6

[0043] The manganese-based composite single-atom catalyst of this embodiment uses manganese as an active component, cobalt as a first auxiliary agent, carbon as a second auxiliary agent, and zinc oxide as a carrier. Based on 100% by mass of the catalyst, the manganese content is 1.5%, the cobalt content is 0.3%, and the carbon content is 1%. The catalyst is prepared as follows:

[0044] Weigh 38.8 mg of manganese chloride, 9.6 mg of cobalt nitrate, 13.8 mg of fruit acid, and 11.87 mg of sucrose and dissolve them in 50 mL of deionized water. Heat to 60°C under stirring, add 1 g of zinc oxide powder, stir thoroughly at 60°C for 1 hour, cover with plastic wrap, age for 12 hours, place in a drying oven at 80°C for 8 hours, take out and grind into fine powder, then place in a tubular furnace, heat to 450°C at a heating rate of 5°C / min under vacuum conditions, calcine at a constant temperature for 1.5 hours, cool naturally to room temperature and take out to obtain a manganese-based composite single-atom catalyst.

[0045] 30 mg of the manganese-based composite single-atom catalyst and 28 mL of acetonitrile were added to a 100 mL autoclave. After sealing, propane and oxygen were introduced sequentially at a propane pressure of 0.6 MPa and an oxygen pressure of 1.2 MPa, respectively. The reaction was stirred at 175°C for 6 h at a speed of 600 rpm. The liquid product was collected, filtered, and quantitatively analyzed by gas chromatography-mass spectrometry. The reaction results are shown in Table 1.

[0046] Example 7

[0047] The manganese-based composite single-atom catalyst of this embodiment uses manganese as an active component, cobalt as a first auxiliary agent, nitrogen as a second auxiliary agent, and zinc oxide as a carrier. Based on 100% by mass of the catalyst, the manganese content is 1.5%, the cobalt content is 0.3%, and the nitrogen content is 0.6%. The catalyst is prepared as follows:

[0048] Weigh 38.8 mg of manganese chloride, 9.6 mg of cobalt nitrate, and 39.6 mg of amino acid and dissolve them in 50 mL of deionized water. Heat to 60 ° C under stirring, add 1 g of zinc oxide powder, stir thoroughly at 60 ° C for 1 hour, cover with plastic wrap, age for 12 hours, place in a drying oven at 80 ° C for 8 hours, take out and grind into fine powder, then place in a tubular furnace, heat to 400 ° C at a heating rate of 5 ° C / min under vacuum conditions, calcine at a constant temperature for 1.5 hours, cool naturally to room temperature and take out to obtain a manganese-based composite single atom catalyst.

[0049] 30 mg of the manganese-based composite single-atom catalyst and 28 mL of acetonitrile were added to a 100 mL autoclave. After sealing, propane and oxygen were introduced sequentially at a propane pressure of 0.6 MPa and an oxygen pressure of 1.2 MPa, respectively. The reaction was stirred at 175°C for 6 h at a speed of 600 rpm. The liquid product was collected, filtered, and quantitatively analyzed by gas chromatography-mass spectrometry. The reaction results are shown in Table 1.

[0050] Example 8

[0051] The manganese-based composite single-atom catalyst of this embodiment uses manganese as an active component, cobalt as a first auxiliary agent, nitrogen and carbon as second auxiliary agents, and zinc oxide as a carrier. Based on the mass of the catalyst as 100%, the manganese content is 0.3%, the cobalt content is 0.3%, the nitrogen content is 0.5%, and the carbon content is 0.4%. The catalyst is prepared as follows:

[0052] Weigh 16 mg of manganese nitrate, 9.6 mg of cobalt nitrate, 10.7 mg of ethylenediamine, and 9.5 mg of maltose and dissolve them in 50 mL of deionized water. Heat to 60°C under stirring, add 1 g of zinc oxide, stir thoroughly at 60°C for 1 hour, cover with plastic wrap, age for 12 hours, place in a drying oven at 80°C and dry for 8 hours. After taking out, grind into fine powder, then place in a tubular furnace, heat to 400°C at a heating rate of 5°C / min under vacuum conditions, calcine at a constant temperature for 1.5 hours, cool naturally to room temperature and take out to obtain a manganese-based composite single-atom catalyst.

[0053] 30 mg of the manganese-based composite single-atom catalyst and 28 mL of acetonitrile were added to a 100 mL autoclave. After sealing, propane and oxygen were introduced sequentially at a propane pressure of 0.6 MPa and an oxygen pressure of 1.2 MPa, respectively. The reaction was stirred at 175°C for 6 h at a speed of 600 rpm. The liquid product was collected, filtered, and quantitatively analyzed by gas chromatography-mass spectrometry. The reaction results are shown in Table 1.

[0054] Example 9

[0055] The manganese-based composite single-atom catalyst of this embodiment has manganese as an active component, iron as a first auxiliary agent, nitrogen as a second auxiliary agent, and niobium pentoxide as a carrier. Based on the mass of the catalyst as 100%, the manganese content is 1%, the iron content is 0.3%, and the nitrogen content is 0.5%. The catalyst is prepared as follows:

[0056] Weigh 30.2 mg of manganese sulfate, 7.2 mg of ferric nitrate nonahydrate, and 10.7 mg of ethylenediamine and dissolve them in 50 mL of deionized water. Heat to 60°C under stirring, add 1 g of niobium pentoxide powder, stir thoroughly at 60°C for 1 hour, cover with plastic wrap, age for 12 hours, place in a drying oven at 80°C and dry for 8 hours. After taking out, grind into fine powder, then place in a tubular furnace, heat to 500°C at a heating rate of 5°C / min under vacuum conditions, calcine at a constant temperature for 1.5 hours, cool naturally to room temperature and take out to obtain a manganese-based composite single-atom catalyst.

[0057] 30 mg of the manganese-based composite single-atom catalyst and 28 mL of acetonitrile were placed in a 100 mL autoclave. After sealing, propane and oxygen were introduced sequentially at a propane pressure of 0.6 MPa and an oxygen pressure of 1.2 MPa, respectively. The reaction was stirred at 160°C for 6 h at a speed of 600 rpm. The liquid product was collected and filtered for quantitative analysis using a gas chromatograph-mass spectrometer. The reaction results are shown in Table 1.

[0058] Example 10

[0059] The manganese-based composite single-atom catalyst of this embodiment has manganese as an active component, iron as a first auxiliary agent, carbon as a second auxiliary agent, and niobium pentoxide as a carrier. Based on the mass of the catalyst as 100%, the manganese content is 0.6%, the iron content is 0.3%, and the carbon content is 0.6%. The catalyst is prepared as follows:

[0060] Weigh 32 mg of manganese nitrate, 7.2 mg of ferric nitrate ninehydrate, and 14.25 mg of maltose and dissolve them in 50 mL of deionized water. Heat to 60°C under stirring, add 1 g of niobium pentoxide powder, stir thoroughly at 60°C for 1 hour, cover with plastic wrap, age for 12 hours, place in a drying oven at 80°C for 8 hours, take out and grind into fine powder, then place in a tubular furnace, heat to 500°C at a heating rate of 7°C / min under vacuum conditions, calcine at a constant temperature for 1.5 hours, cool naturally to room temperature and take out to obtain a manganese-based composite single-atom catalyst.

[0061] 30 mg of the manganese-based composite single-atom catalyst and 28 mL of acetonitrile were placed in a 100 mL autoclave. After sealing, propane and oxygen were introduced sequentially at a propane pressure of 0.6 MPa and an oxygen pressure of 1.2 MPa. The reaction was stirred at 180°C for 6 h at a speed of 600 rpm. The liquid product was collected and filtered for quantitative analysis using a gas chromatograph-mass spectrometer. The reaction results are shown in Table 1.

[0062] Table 1 Catalytic performance of different catalysts in the reaction

[0063] catalyst <![CDATA[Acetone yield (mmol 产物 g 催化剂 -1 h -1 )]]> Selectivity of acetone in liquid products Example 1 54.15 65.02％ Example 2 46.54 51.25％ Example 3 45.35 48.15％ Example 4 50.35 56.63％ Example 5 51.53 61.95％ Example 6 43.58 44.51％ Example 7 42.68 42.77％ Example 8 52.58 62.12％ Example 9 43.52 51.21％ Example 10 47.01 52.16％

[0064] The catalyst and catalytic reaction conditions of Example 1 were further used to test the stability of the catalyst. The results are shown in Table 2.

[0065] Table 2 Test results of catalyst cycle 5 times in Example 1

[0066]

[0067]

[0068] The experimental results in Tables 1 and 2 show that the manganese-based composite single-atom catalyst of the present invention can be used in the propane oxidation reaction with oxygen as the oxidant to achieve high efficiency and high selectivity to obtain acetone under low temperature conditions, with an acetone yield of 45 to 55 mmol g 催化剂 -1 h -1 The acetone content in the liquid product can reach up to 65%, and the catalyst has excellent stability and can be stably cycled 5 times without obvious deactivation.

Claims

1. A manganese-based composite single-atom catalyst for low-temperature oxidation of propane to acetone, characterized by: The manganese-based composite single-atom catalyst comprises manganese as an active component, at least one of iron, cobalt, copper, and nickel as a first auxiliary agent, at least one of carbon and nitrogen as a second auxiliary agent, and at least one of aluminum oxide, cerium oxide, zinc oxide, zirconium oxide, and niobium pentoxide as a carrier; based on 100% by mass of the catalyst, the content of the active component is 0.1% to 1.5%, the content of the first auxiliary agent is 0.1% to 0.5%, and the content of the second auxiliary agent is 0.5% to 1%; The preparation method of the above-mentioned manganese-based composite single-atom catalyst is as follows: dissolving the manganese precursor, the first auxiliary agent precursor, and the second auxiliary agent precursor in deionized water, stirring and heating to 60-80°C, and then adding the carrier thereto and continuously The mixture is stirred and heated until it becomes a viscous paste, taken out, covered with plastic wrap, and then aged, dried, ground, and vacuum-baked to obtain a manganese-based composite single-atom catalyst in which the active components and additives are highly dispersed on the carrier in the form of single atoms.

2. The manganese-based composite single-atom catalyst for low-temperature oxidation of propane to acetone according to claim 1, characterized in that: The manganese precursor is any one of manganese nitrate, manganese sulfate and manganese chloride.

3. The manganese-based composite single-atom catalyst for low-temperature oxidation of propane to acetone according to claim 1, characterized in that: The precursor of the first auxiliary agent iron is any one of ferric nitrate, ferric oxalate, and ammonium ferric citrate; the precursor of the first auxiliary agent cobalt is any one of cobalt nitrate, cobalt acetylacetonate, and cobalt oxalate; the precursor of the first auxiliary agent copper is copper nitrate or copper sulfate; and the precursor of the first auxiliary agent nickel is nickel nitrate or nickel oxalate.

4. The manganese-based composite single-atom catalyst for low-temperature oxidation of propane to acetone according to claim 1, characterized in that: The precursor of the second auxiliary agent carbon element is at least one of fructose, sucrose, maltose, and oxalic acid, and the precursor of the second auxiliary agent nitrogen element is at least one of ethylenediamine, amino acid, and dimethylimidazole.

5. The manganese-based composite single-atom catalyst for low-temperature oxidation of propane to acetone according to claim 1, characterized in that: In the preparation method of the manganese-based composite single-atom catalyst, the stirring speed is 500 to 800 r / min, and the stirring and heating time after adding the carrier is continuous for 1 to 3 hours.

6. The manganese-based composite single-atom catalyst for low-temperature oxidation of propane to acetone according to claim 1, characterized in that: In the preparation method of the manganese-based composite single-atom catalyst, the aging time is 8 to 12 hours, the drying temperature is 100 to 150° C., and the drying time is 4 to 8 hours.

7. The manganese-based composite single-atom catalyst for low-temperature oxidation of propane to acetone according to claim 1, characterized in that: In the preparation method of the manganese-based composite single-atom catalyst, the vacuum calcination temperature is 300-500° C. and the time is 1-4 hours.

8. A method for preparing acetone by low-temperature oxidation of propane, characterized in that: The manganese-based composite single-atom catalyst according to any one of claims 1 to 7 and acetonitrile are added to a high-pressure reactor, which is sealed and then introduced with propane and oxygen in sequence, with the propane pressure being 0.3 to 0.8 MPa and the oxygen pressure being 0.5 to 1.5 MPa, and the reaction is stirred at 100 to 200° C. for 4 to 12 hours.

9. The method for preparing acetone by low-temperature oxidation of propane according to claim 8, wherein: Stir the reaction at 160-180°C for 5-7 hours.

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