A catalyst for the oxidative dehydrogenation of propane to propylene, a process for its preparation and a process for the production of propylene

Abstract

The application discloses a kind of propane oxidation dehydrogenation monatomic system catalyst, its preparation method and preparation propylene method.The propane oxidation dehydrogenation catalyst of the application includes active component and carrier, the active component is loaded on the carrier, the active component is Pt monatomic and In monatomic, the carrier is aluminium oxide;The mass percentage content of the active component Pt in the propane oxidation dehydrogenation catalyst is 0.1%~10%;The mass percentage content of the active component In in the propane oxidation dehydrogenation catalyst is 1%~20%.The propane oxidation dehydrogenation monatomic system catalyst of the application takes Pt and In monatomic as active component, aluminium oxide as carrier, after adding adjuvant, propane conversion and propylene selectivity will be further improved, with the characteristics of simple synthesis method, high propylene yield, excellent stability, realizes the purpose of high conversion rate high selectivity catalytic propane oxidation dehydrogenation preparation propylene, in 100 hours of stability test, propylene yield is not obviously reduced.

Description

Technical Field

[0001] This invention belongs to the field of catalysis, and particularly relates to a propane oxidative dehydrogenation single-atom system catalyst, its preparation method, and a method for producing propylene. Background Technology

[0002] Propylene is a raw material for the production of high-value-added chemicals such as polypropylene. In recent years, the rapid rise of the shale gas industry has led to an increase in propane production, providing profit margins and economic value for the propane dehydrogenation to propylene reaction.

[0003] Direct propane dehydrogenation to propylene offers the advantage of high selectivity and is widely used in industry. However, this process is limited by thermodynamic equilibrium, is strongly endothermic, and requires a significant external heat of reaction. Therefore, the reaction typically proceeds at high temperature and low pressure, under which the catalyst rapidly deactivates due to carbon buildup. In contrast, oxidative dehydrogenation of propane (ODHP) to propylene is not limited by thermodynamic equilibrium and is exothermic, allowing it to proceed at relatively low temperatures. Furthermore, oxygen effectively mitigates catalyst carbon buildup. Consequently, oxidative dehydrogenation of propane has received widespread attention from both academia and industry in recent years.

[0004] Catalysts for the oxidative dehydrogenation of propane to propylene include various transition metal oxides, such as vanadium (ACS Catal., 2015, 5, 5787–5793), molybdenum (J. Mol. Catal. A, 2014, 392, 315), and chromium (Journal of Catalysis, 2017, 356: 197-205), as well as hexagonal boron nitride (h-BN) (Science, 2016, 354: 1570-1573) and S-1 molecular sieves supporting B single-atom sites, and Pt / Al2O3 core-In2O3 shell catalysts prepared by atomic layer deposition. However, due to the peroxidation that produces CO during the oxidative dehydrogenation of propane... x The product yield still makes the propylene yield uneconomical. Among them, h-BN can achieve a propylene conversion of 14% and a propylene selectivity of 79%, while the Pt / Al2O3 core-In2O3 shell catalyst has a propylene conversion of 32% and a propylene selectivity of 70%. The propylene selectivity gradually decreases with reaction time, and both Pt and In2O3 in the Pt / Al2O3 core-In2O3 shell catalyst are dispersed as nanoparticles.

[0005] Therefore, optimizing the composition of the catalyst, the synthesis method of the catalyst, and the structure of the catalyst to construct an excellent catalyst for the oxidative dehydrogenation of propane to propylene and obtain an economically valuable propylene yield remains a huge challenge. Summary of the Invention

[0006] To achieve an economically viable propylene yield, the present invention aims to provide a propane oxidative dehydrogenation single-atom system catalyst, its preparation method, and a method for producing propylene. This propane oxidative dehydrogenation catalyst uses Pt and In single atoms as active components and alumina as a support. The addition of auxiliary agents will further improve the propane conversion and propylene selectivity. It features a simple synthesis method and a high propylene yield.

[0007] In a first aspect, the present invention provides a propane oxidative dehydrogenation catalyst, comprising an active component and a support, wherein the active component is supported on the support, the active component being a single Pt atom and a single In atom, and the support being alumina;

[0008] The active component Pt in the propane oxidative dehydrogenation catalyst has a mass percentage content of 0.1% to 10%.

[0009] The active component In in the propane oxidative dehydrogenation catalyst has a mass percentage content of 1% to 20%.

[0010] In the above-mentioned propane oxidative dehydrogenation catalyst, the mass percentage of the active component Pt in the propane oxidative dehydrogenation catalyst can specifically be 3%, 5%, 1%, 10%, or 0.1%.

[0011] In the above-mentioned propane oxidative dehydrogenation catalyst, the mass percentage of the active component In in the propane oxidative dehydrogenation catalyst can be 1% to 15%, 10%, 15%, 3%, 12%, or 1%.

[0012] Preferably, the active component Pt has a mass percentage content of 1% to 10% in the propane oxidative dehydrogenation catalyst, and the active component In has a mass percentage content of 1% to 15% in the propane oxidative dehydrogenation catalyst.

[0013] More preferably, the active component Pt has a mass percentage content of 1% to 5% in the propane oxidative dehydrogenation catalyst, and the active component In has a mass percentage content of 3% to 15% in the propane oxidative dehydrogenation catalyst;

[0014] More preferably, the active component Pt has a mass percentage content of 3% to 5% in the propane oxidative dehydrogenation catalyst, and the active component In has a mass percentage content of 10% to 15% in the propane oxidative dehydrogenation catalyst.

[0015] More preferably, the active component Pt has a mass percentage content of 3% in the propane oxidative dehydrogenation catalyst, and the active component In has a mass percentage content of 10% in the propane oxidative dehydrogenation catalyst.

[0016] Secondly, the present invention provides a method for preparing the propane oxidative dehydrogenation catalyst, comprising the following steps:

[0017] The precursors of Pt and In were added to an aqueous dispersion of alumina, and the mixture was stirred, dried for the first time, calcined for the first time, and reduced at different temperature ranges in sequence to obtain the propane oxidative dehydrogenation catalyst.

[0018] In the above-mentioned method for preparing propane oxidative dehydrogenation catalyst, the precursor of Pt is chloroplatinic acid;

[0019] The precursor of In is indium nitrate;

[0020] The concentration of alumina in the aqueous dispersion of alumina can be 0.002–0.2 g / mL, specifically 0.02 g / mL;

[0021] The temperature of the first drying step can be 50-80℃, specifically 80℃, and the time can be 8-12 hours, specifically 10 hours.

[0022] The temperature of the first roasting can be 500-750℃, specifically 550℃, and the time can be 1-3 hours, specifically 2 hours;

[0023] The first firing was carried out in an air atmosphere;

[0024] The reduction at different temperature ranges was carried out in a 10% H2 atmosphere, and was carried out sequentially at 150℃, 200℃, 250℃ and 490℃ for 0.5 to 2 hours respectively.

[0025] Thirdly, the present invention protects a propane oxidative dehydrogenation catalyst, comprising an active component, a support, and an auxiliary agent, wherein the active component and the auxiliary agent are loaded on the support, the active component is a single Pt atom and a single In atom, the auxiliary agent is one or more of gold, silver, palladium, ruthenium, cobalt, cerium, and copper, and the support is alumina;

[0026] The active component Pt in the propane oxidative dehydrogenation catalyst has a mass percentage content of 0.1% to 10%.

[0027] The active component In in the propane oxidative dehydrogenation catalyst has a mass percentage content of 1% to 20%;

[0028] The mass percentage of each of the aforementioned additives in the propane oxidative dehydrogenation catalyst is 0.03% to 8%.

[0029] In the above-mentioned propane oxidative dehydrogenation catalyst, the mass percentage of each of the auxiliary agents in the propane oxidative dehydrogenation catalyst can be 0.03%, 0.1%, 0.5%, 1%, 3%, 5%, or 8%. Taking palladium as an example, it is preferably 0.03% to 8%, 0.1% to 8%, more preferably 0.5% to 1%, and even more preferably 1%.

[0030] In the above-mentioned propane oxidative dehydrogenation catalyst, the promoter may include a first promoter and a second promoter, which are either of the following:

[0031] 1) The first additive is palladium, and the second additive is any one of ruthenium, cobalt, cerium, and copper;

[0032] 2) The first additive is cobalt, and the second additive is cerium.

[0033] In technical solution 1), the mass percentage of the first auxiliary agent is 1% to 5% (e.g., 1%, 3%, or 5%), and the mass percentage of the second auxiliary agent is 1% to 8%. Preferably, the mass percentage of the first auxiliary agent is 3% to 5%, and the mass percentage of the second auxiliary agent is 3% to 5%. More preferably, the mass percentage of the first auxiliary agent is 3%, and the mass percentage of the second auxiliary agent is 3%.

[0034] In technical solution 2), the mass percentage of cobalt is 3% to 8% (e.g., 3%, 5%, or 8%), and the mass percentage of cerium is 1% to 8% (e.g., 1%, 3%, 5%, 7%, or 8%). Preferably, the mass percentage of cobalt is 3% to 8%, and the mass percentage of cerium is 1% to 7%. More preferably, the mass percentage of cobalt is 3% to 8%, and the mass percentage of cerium is 1% to 5%. Even more preferably, the mass percentage of cobalt is 3% to 5%, and the mass percentage of cerium is 1% to 3%. Still more preferably, the mass percentage of cobalt is 3%, and the mass percentage of cerium is 1%.

[0035] Fourthly, the present invention provides a method for preparing the propane oxidative dehydrogenation catalyst, comprising the following steps:

[0036] (1) Add the precursors of Pt and In to the aqueous dispersion of alumina, and then stir, dry for the first time, calcine for the first time and reduce at different temperature ranges in sequence.

[0037] (2) The product after the first calcination is immersed in an aqueous solution of the precursor of the auxiliary agent, and then subjected to a second drying and a second calcination to obtain the propane oxidative dehydrogenation catalyst.

[0038] In the above preparation method, the precursor of Pt is chloroplatinic acid;

[0039] The precursor of In is indium nitrate;

[0040] The concentration of alumina in the aqueous dispersion of alumina can be 0.002–0.2 g / mL, specifically 0.02 g / mL;

[0041] The temperature of the first drying step can be 50-80℃, specifically 80℃, and the time can be 8-12 hours, specifically 10 hours.

[0042] The temperature of the first roasting can be 500-750℃, specifically 550℃, and the time can be 1-3 hours, specifically 2 hours;

[0043] The first firing was carried out in an air atmosphere;

[0044] The reduction at different temperature ranges was carried out in a 10% H2 atmosphere, and was performed at 150℃, 200℃, 250℃ and 490℃ for 0.5 to 2 hours respectively.

[0045] The precursor of the auxiliary agent is the chloride, nitrate, sulfate or acetate of the auxiliary agent;

[0046] The concentration of the precursor of the adjuvant in the aqueous solution of the precursor of the adjuvant can be 0.02-0.04 g / ml, specifically 0.04 g / ml;

[0047] The temperature for the second drying can be 50-80℃, specifically 80℃, and the time can be 8-12 hours, specifically 10 hours;

[0048] The temperature of the second roasting can be 150-450℃, specifically 225℃, and the time can be 2-4 hours, specifically 3 hours;

[0049] The second roasting is carried out in an air atmosphere.

[0050] Fifthly, the present invention provides a method for catalytic oxidative dehydrogenation of propane to propylene, comprising the following steps:

[0051] In the presence of oxygen and dilution gas, propane undergoes oxidative dehydrogenation under the catalysis of any of the propane oxidative dehydrogenation catalysts described above to obtain propylene.

[0052] In the above method, the propane oxidative dehydrogenation catalyst is heated to the oxidative dehydrogenation temperature under a reducing atmosphere;

[0053] The reducing atmosphere consists of a reducing gas with a volume percentage of 1% to 10% (e.g., 10%) and the balance gas.

[0054] The balancing gas is nitrogen or argon;

[0055] The reducing gas is hydrogen or carbon monoxide.

[0056] In the above method, the volume percentage of propane in the reaction gas composed of propane, oxygen and dilution gas is 3% to 20%, such as 4.3%.

[0057] The oxygen content in the reaction gas composed of the propane, the oxygen, and the dilution gas is 1.5% to 10% by volume, such as 2.15%.

[0058] The dilution gas is nitrogen, helium, or argon.

[0059] The temperature for the oxidative dehydrogenation is 400–600°C, such as 490°C;

[0060] The space-time velocity of the propane oxidative dehydrogenation catalyst is 42-60 L / g / h, such as 42 L / g / h, based on the amount of reaction gas passing through each gram of catalyst per unit time.

[0061] The present invention has the following advantages:

[0062] Compared with existing technologies, this invention has the following advantages: First, the preparation method is simple and the synthesis cycle is short; a highly efficient catalyst can be obtained simply by stirring and calcining, resulting in extremely high synthesis efficiency. Second, at a reaction temperature of 490℃, the propylene yield surpasses that of transition metal oxides and boron nitride catalysts above 500℃, achieving the goal of high-conversion and high-selectivity catalytic oxidative dehydrogenation of propane to propylene. Third, the material exhibits excellent stability; in a 100-hour stability test, the propylene yield did not decrease significantly. Therefore, this catalyst has promising application prospects and economic value. Attached Figure Description

[0063] Figure 1 The results of spherical aberration electron microscopy characterization of Pt single atoms and In single atoms in Example 1 of the present invention show that the brightness of Pt single atoms is higher than that of In single atoms, and both Pt and In in the catalyst of the present invention are dispersed in single-atom form, exhibiting high dispersion. Detailed Implementation

[0064] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0065] Unless otherwise specified, the methods used in the following embodiments are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following embodiments are commercially available.

[0066] In the following embodiments, the conversion rate and selectivity are calculated as follows:

[0067] Alkane conversion rate (%) = [(moles of alkanes before reaction - moles of alkanes after reaction) / moles of alkanes before reaction] × 100%;

[0068] Product selectivity (%) = [Number of carbon atoms in the product / (Number of alkane carbon atoms before reaction - Number of alkane carbon atoms after reaction)] × 100%;

[0069] Product yield (%) = Alkane conversion rate × Product selectivity

[0070] In the following embodiments, the reaction spacetime velocity is calculated as follows:

[0071] Reaction space velocity = Volume of reaction gas per hour (L) / Mass of catalyst (g).

[0072] Unless otherwise specified, the roasting in the following examples is carried out in air.

[0073] The gas chromatographic conditions for testing propylene were as follows: FID detector temperature 250℃, hydrogen flow rate 40 ml / min, air flow rate 400 ml / min, column oven temperature 35℃ for 2 min, then increased to 85℃ at a rate of 10℃ / min. Column flow rate was 7 ml / min.

[0074] All load values ​​in the following examples are theoretical load values.

[0075] Example 1

[0076] The preparation process of the catalyst Pt-In / Al2O3 in this embodiment is as follows:

[0077] Weigh 10g of alumina, add 500ml of water to make a suspension, add 2.63g of indium nitrate and 16.7ml of chloroplatinic acid aqueous solution (18.0mg / ml), stir at room temperature for 10 hours, dry at 80℃ overnight (10 hours), calcine in a muffle furnace at 550℃ for 2 hours, and then reduce in a 10% H2 atmosphere at 150℃, 200℃, 250℃ and 490℃ for 0.5 hours respectively.

[0078] The catalyst Pt-In / Al2O3 prepared in this example has a Pt mass fraction of 3% and an In mass fraction of 10%, and is denoted as 3Pt-10In / Al2O3.

[0079] 0.1 g of 3Pt-10In / Al2O3 was placed in a fixed-bed reactor and heated to 490 °C in a 10% hydrogen atmosphere (with nitrogen as the equilibrium gas). The hydrogen gas was then shut off, and a reaction gas was introduced, consisting of 4.3% propane, 2.15% oxygen, and the remainder nitrogen, at a space-time velocity of 42 L / g / h. The activity evaluation results are shown in Table 1.

[0080] Table 1. Catalytic activity in Example 1

[0081] Propane oxidative dehydrogenation performance ％ propane conversion rate 42 propylene selectivity 61 propylene yield 25.6

[0082] Example 2

[0083] The preparation process of the catalyst Pt-In / Al2O3 described in this embodiment is as follows:

[0084] Weigh 10g of alumina, add 500ml of water to make a suspension, add 3.95g of indium nitrate and 27.8ml of an aqueous solution of chloroplatinic acid (18.0mg / ml), stir at room temperature for 10 hours, dry at 70℃ overnight, calcine in a muffle furnace at 650℃ for 3 hours, and then reduce in a 10% H2 atmosphere at 150℃, 200℃, 250℃ and 490℃ for 0.5 hours respectively.

[0085] The catalyst Pt-In / Al2O3 prepared in this example has a Pt mass fraction of 5% and an In mass fraction of 15%, and is denoted as 5Pt-15In / Al2O3.

[0086] The material catalytic propane oxidative dehydrogenation test was the same as in Example 1, and the dehydrogenation activity evaluation results are shown in Table 2.

[0087] Table 2, Catalytic Activity in Example 2

[0088] Propane oxidative dehydrogenation performance ％ propane conversion rate 37 propylene selectivity 57 propylene yield 21.1

[0089] Example 3

[0090] The preparation process of the catalyst Pt-In / Al2O3 described in this embodiment is as follows:

[0091] Weigh 10g of alumina, add 500ml of water to make a suspension, add 0.79g of indium nitrate and 5.6ml of chloroplatinic acid aqueous solution (18.0mg / ml), stir at room temperature for 10 hours, dry at 60℃ overnight, calcine in a muffle furnace at 500℃ for 1 hour, and then reduce in a 10% H2 atmosphere at 150℃, 200℃, 250℃ and 490℃ for 0.5 hours respectively.

[0092] The catalyst Pt-In / Al2O3 prepared in this example has a Pt mass fraction of 1% and an In mass fraction of 3%, and is denoted as Pt-3In / Al2O3.

[0093] The material catalytic propane oxidative dehydrogenation test was the same as in Example 1, and the activity evaluation results are shown in Table 3.

[0094] Table 3, Catalytic activity in Example 3

[0095] Propane oxidative dehydrogenation performance ％ propane conversion rate 32 propylene selectivity 51 propylene yield 16.3

[0096] Example 4

[0097] The preparation process of the catalyst Pt-In / Al2O3 described in this embodiment is as follows:

[0098] Weigh 10g of alumina, add 500ml of water to make a suspension, add 3.16g of indium nitrate and 56ml of an aqueous solution of chloroplatinic acid (18.0mg / ml), stir at room temperature for 10 hours, dry at 60℃ overnight, calcine in a muffle furnace at 500℃ for 1 hour, and then reduce in a 10% H2 atmosphere at 150℃, 200℃, 250℃ and 490℃ for 0.5 hours respectively.

[0099] The catalyst Pt-In / Al2O3 prepared in this example has a Pt mass fraction of 10% and an In mass fraction of 12%, and is denoted as 10Pt-12In / Al2O3.

[0100] The material catalytic propane oxidative dehydrogenation test was the same as in Example 1, and the activity evaluation results are shown in Table 4.

[0101] Table 4, Catalytic Activity in Example 4

[0102] Propane oxidative dehydrogenation performance ％ propane conversion rate 16 propylene selectivity 52 propylene yield 8.3

[0103] Example 5

[0104] The preparation process of the catalyst Pt-In / Al2O3 described in this embodiment is as follows:

[0105] Weigh 10g of alumina, add 500ml of water to make a suspension, add 0.26g of indium nitrate and 16.7ml of an aqueous solution of chloroplatinic acid (18.0mg / ml), stir at room temperature for 10 hours, dry at 60℃ overnight, calcine in a muffle furnace at 500℃ for 1 hour, and then reduce in a 10% H2 atmosphere at 150℃, 200℃, 250℃ and 490℃ for 0.5 hours respectively.

[0106] The catalyst Pt-In / Al2O3 prepared in this example has a Pt mass fraction of 3% and an In mass fraction of 1%, and is denoted as 3Pt-In / Al2O3.

[0107] The material catalytic propane oxidative dehydrogenation test was the same as in Example 1, and the activity evaluation results are shown in Table 5.

[0108] Table 5, Catalytic activity in Example 5

[0109] Propane oxidative dehydrogenation performance ％ propane conversion rate 20 propylene selectivity 42 propylene yield 8.4

[0110] Comparative Example 1

[0111] The preparation process of the comparative catalyst Pt / Al2O3 is as follows:

[0112] The preparation process is the same as in Example 1, except that the addition of indium nitrate is omitted.

[0113] The catalyst Pt / Al2O3 prepared in this comparative example has a Pt mass fraction of 3%, denoted as 3Pt / Al2O3.

[0114] The results of the activity evaluation are shown in Table 6.

[0115] Table 6. Catalytic activity of Comparative Example 1

[0116] Propane oxidative dehydrogenation performance ％ propane conversion rate 5 propylene selectivity 22 propylene yield 11

[0117] Comparative Example 2

[0118] The preparation process of the comparative catalyst In / Al2O3 is as follows:

[0119] The preparation process is the same as in Example 1, except that the addition of chloroplatinic acid aqueous solution is omitted.

[0120] The mass fraction of In in the In / Al2O3 catalyst prepared in this comparative example is 3%, denoted as 10In / Al2O3.

[0121] The activity evaluation results are shown in Table 7.

[0122] Table 7. Catalytic activity of Comparative Example 1

[0123] Propane oxidative dehydrogenation performance ％ propane conversion rate 2 propylene selectivity 17 propylene yield 3.4

[0124] Comparative Example 3

[0125] The preparation process of the catalyst Pt-In / Al2O3 described in this embodiment is as follows:

[0126] Weigh 10g of alumina, add 500ml of water to make a suspension, add 0.26g of indium nitrate and 0.56ml of chloroplatinic acid aqueous solution (18.0mg / ml), stir at room temperature for 10 hours, dry at 60℃ overnight, and calcine in a muffle furnace at 500℃ for 1 hour.

[0127] The catalyst Pt-In / Al2O3 prepared in this example has a Pt mass fraction of 0.1% and an In mass fraction of 1%, denoted as 0.1Pt-In / Al2O3.

[0128] The material catalytic propane oxidative dehydrogenation test was the same as in Example 1, and the activity evaluation results are shown in Table 8.

[0129] Table 8. Catalytic activity of Comparative Example 1

[0130] Propane oxidative dehydrogenation performance ％ propane conversion rate 10 propylene selectivity 39 propylene yield 3.9

[0131] Figure 1 The results of spherical aberration electron microscopy characterization of Pt single atoms and In single atoms in Example 1 of the present invention show that the brightness of Pt single atoms is higher than that of In single atoms, and both Pt and In in the catalyst of the present invention are dispersed in single-atom form, exhibiting high dispersion.

[0132] As can be seen from Example 1 and Comparative Examples 1-2 above, the catalyst of the present invention uses Pt and In single atoms as active components, which greatly improves the catalytic activity compared to a single active component.

[0133] As can be seen from Examples 1-5 and Comparative Example 3 above, the mass fractions of Pt and In in the catalyst directly affect the activity of the catalyst. The mass percentage of Pt is preferably 1% to 10%, more preferably 1% to 5%, and even more preferably 3% to 5%; the mass percentage of In is preferably 1% to 15%, more preferably 3% to 15%, and even more preferably 10% to 15%.

[0134] Example 6

[0135] The preparation process of the catalyst M / Pt-In / Al2O3 described in this embodiment is as follows:

[0136] (1) 3Pt-10In / Al2O3 was prepared as described in Example 1.

[0137] (2) Dissolve 1g of palladium nitrate in 25ml of water as a precursor for palladium auxiliary agent. Weigh 0.4g of 3Pt-10In / Al2O3 and add 0.0065ml of palladium nitrate solution to make the palladium loading 0.03%. Dry at 80℃ overnight (10 hours) and calcine in a muffle furnace at 225℃ for 3 hours to obtain a catalyst containing palladium auxiliary agent, denoted as 0.03Pd / 3Pt-10In / Al2O3.

[0138] The material catalytic propane oxidative dehydrogenation test was the same as in Example 1, and the activity evaluation results are shown in Table 9.

[0139] Table 9, Catalytic Activity in Example 6

[0140] Propane oxidative dehydrogenation performance ％ propane conversion rate 45 propylene selectivity 62 propylene yield 27.9

[0141] Example 7

[0142] The rest is the same as in Example 6, except that the palladium loading is 0.1%, and the activity evaluation results are shown in Table 10.

[0143] Table 10, Catalytic Activity in Example 7

[0144] Propane oxidative dehydrogenation performance ％ propane conversion rate 45 propylene selectivity 63 propylene yield 28.4

[0145] Example 8

[0146] The rest is the same as in Example 6, except that the palladium loading is 0.5%, and the activity evaluation results are shown in Table 11.

[0147] Table 11, Catalytic activity in Example 8

[0148] Propane oxidative dehydrogenation performance ％ propane conversion rate 47 propylene selectivity 63 propylene yield 29.6

[0149] Example 9

[0150] The rest is the same as in Example 6, except that the palladium loading is 1%, and the activity evaluation results are shown in Table 12.

[0151] Table 12, Catalytic Activity in Example 9

[0152] Propane oxidative dehydrogenation performance ％ propane conversion rate 49 propylene selectivity 62 propylene yield 30.4

[0153] Example 10

[0154] The rest is the same as in Example 6, except that the palladium loading is 3%, and the activity evaluation results are shown in Table 13.

[0155] Table 13, Catalytic Activity in Example 10

[0156] Propane oxidative dehydrogenation performance ％ propane conversion rate 49 propylene selectivity 61 propylene yield 28.9

[0157] Example 11

[0158] The rest is the same as in Example 6, except that the palladium loading is 5%, and the activity evaluation results are shown in Table 14.

[0159] Table 14, Catalytic Activity in Example 11

[0160] Propane oxidative dehydrogenation performance ％ propane conversion rate 48 propylene selectivity 62 propylene yield 29.8

[0161] Example 12

[0162] The rest is the same as in Example 6, except that the palladium loading is 8%, and the activity evaluation results are shown in Table 15.

[0163] Table 15, Catalytic Activity in Example 12

[0164] Propane oxidative dehydrogenation performance ％ propane conversion rate 47 propylene selectivity 62 propylene yield 29.1

[0165] Comparative Example 4

[0166] The preparation process of the catalyst M / 3Pt-10In / Al2O3 described in this embodiment is as follows:

[0167] (1) 3Pt-10In / Al2O3 was prepared as described in Example 1.

[0168] (2) Dissolve 1g of palladium nitrate in 25ml of water as a precursor for palladium auxiliaries. Weigh 0.4g of 3Pt-10In / Al2O3 and add 2.4ml of palladium nitrate solution to make the palladium loading 10%. Dry at 80℃ overnight and calcine in a muffle furnace at 225℃ for 3 hours to obtain a catalyst containing palladium auxiliaries, denoted as 10Pd / 3Pt-10In / Al2O3.

[0169] The material catalytic propane oxidative dehydrogenation test was the same as in Example 1, and the activity evaluation results are shown in Table 16.

[0170] Table 16. Catalytic activity of Comparative Example 2

[0171] Propane oxidative dehydrogenation performance ％ propane conversion rate 45 propylene selectivity 56 propylene yield 25.2

[0172] As can be seen from Examples 6-12 and Comparative Example 4, when palladium is added as an additive, the mass percentage of palladium directly affects the catalytic activity of the catalyst. It can be seen that the mass percentage of palladium is preferably 0.03% to 8%, more preferably 0.1% to 8%, and even more preferably 0.5% to 1%.

[0173] Example 13

[0174] The rest was the same as in Example 10, except that 1 ml of chloroauric acid solution (10.0 mg / ml) was added simultaneously with the palladium nitrate solution, and the gold loading was 1%, denoted as 1Au-3Pd / 3Pt-10In / Al2O3. The activity evaluation results are shown in Table 17.

[0175] Table 17, Catalytic Activity in Example 13

[0176] Propane oxidative dehydrogenation performance ％ propane conversion rate 50 propylene selectivity 55 propylene yield 27.5

[0177] Example 14

[0178] The rest is the same as in Example 10, except that 5 ml of silver nitrate solution (2.0 mg / ml) was added at the same time as palladium nitrate solution. The silver loading was 1%, denoted as 1Ag-3Pd / 3Pt-10In / Al2O3. The activity evaluation results are shown in Table 18.

[0179] Table 18, Catalytic Activity in Example 14

[0180] Propane oxidative dehydrogenation performance ％ propane conversion rate 54 propylene selectivity 52 propylene yield 28.1

[0181] Example 15

[0182] The rest is the same as in Example 10, except that 1 ml of ruthenium chloride solution (10.0 mg / ml) was added at the same time as palladium nitrate solution. The ruthenium loading was 1%, denoted as 1Ru-3Pd / 3Pt-10In / Al2O3. The activity evaluation results are shown in Table 19.

[0183] Table 19, Catalytic Activity in Example 15

[0184] Propane oxidative dehydrogenation performance ％ propane conversion rate 59 propylene selectivity 51 propylene yield 30.1

[0185] Example 16

[0186] The rest is the same as in Example 10, except that 10 ml of cobalt nitrate solution (3.0 mg / ml) was added at the same time as palladium nitrate solution. The cobalt loading was 3%, denoted as 3Co-3Pd / 3Pt-10In / Al2O3. The activity evaluation results are shown in Table 20.

[0187] Table 20, Catalytic Activity in Example 16

[0188] Propane oxidative dehydrogenation performance ％ propane conversion rate 50 propylene selectivity 71 propylene yield 35.5

[0189] Example 17

[0190] The rest is the same as in Example 10, except that 10 ml of cerium nitrate solution (3.0 mg / ml) was added at the same time as palladium nitrate solution. The cerium loading was 3%, denoted as 3Ce-3Pd / 3Pt-10In / Al2O3. The activity evaluation results are shown in Table 21.

[0191] Table 21, Catalytic Activity in Example 17

[0192] Propane oxidative dehydrogenation performance ％ propane conversion rate 50 propylene selectivity 65 propylene yield 32.5

[0193] Example 18

[0194] The rest is the same as in Example 10, except that 3 ml of copper acetate solution (10.0 mg / ml) was added at the same time as palladium nitrate solution. The copper loading was 3%, denoted as 3Cu-3Pd / 3Pt-10In / Al2O3. The activity evaluation results are shown in Table 22.

[0195] Table 22, Catalytic Activity in Example 18

[0196] Propane oxidative dehydrogenation performance ％ propane conversion rate 52 propylene selectivity 67 propylene yield 34.8

[0197] Example 19

[0198] The rest is the same as in Example 18, except that the palladium loading is 5% and the copper loading is 3%. The activity evaluation results are shown in Table 23.

[0199] Table 23, Catalytic Activity in Example 19

[0200] Propane oxidative dehydrogenation performance ％ propane conversion rate 54 propylene selectivity 68 propylene yield 36.7

[0201] Example 20

[0202] The rest is the same as in Example 18, except that the palladium loading is 1% and the copper loading is 4%. The activity evaluation results are shown in Table 24.

[0203] Table 24, Catalytic Activity in Example 20

[0204] Propane oxidative dehydrogenation performance ％ propane conversion rate 50 propylene selectivity 69 propylene yield 34.5

[0205] Comparative Example 5

[0206] The rest is the same as in Example 18, except that the palladium loading is 0.1% and the copper loading is 5%. The activity evaluation results are shown in Table 25.

[0207] Table 25. Catalytic activity of Comparative Example 5

[0208] Propane oxidative dehydrogenation performance ％ propane conversion rate 49 propylene selectivity 52 propylene yield 25.5

[0209] As can be seen from Examples 13-20 and Comparative Example 5, adding a certain amount of other promoters, such as Ru, Co, Ce, and Cu, to 3Pd / 3Pt-10In / Al2O3 can improve its catalytic activity. Taking copper as an example, when the copper loading in the catalyst is 3% to 4%, its catalytic activity can be further improved. When the palladium loading is 0.1% and the copper loading is 5%, the catalytic activity is actually reduced compared to not adding copper.

[0210] Example 21

[0211] The preparation process of the catalyst M / 3Pt-10In / Al2O3 described in this embodiment is as follows:

[0212] (1) 3Pt-10In / Al2O3 was prepared as described in Example 1.

[0213] (2) Dissolve 1g of cobalt nitrate in 25ml of water as a precursor for the cobalt auxiliary agent. Dissolve 1g of cerium nitrate in 25ml of water as a precursor for the cerium auxiliary agent. Weigh 0.4g of 3Pt-10In / Al2O3, add 1.5ml of cobalt nitrate solution, and add 0.28ml of cerium nitrate to make the cobalt loading 3% and the cerium loading 1%. Dry at 80℃ overnight, and calcine in a muffle furnace at 225℃ for 3 hours to obtain a catalyst containing cobalt and cerium auxiliary agents, denoted as 3Co-1Ce / 3Pt-10In / Al2O3.

[0214] The material catalytic propane oxidative dehydrogenation test was the same as in Example 1, and the activity evaluation results are shown in Table 26.

[0215] Table 26, Catalytic Activity in Example 21

[0216] Propane oxidative dehydrogenation performance ％ propane conversion rate 52 propylene selectivity 72 propylene yield 37.4

[0217] Example 22

[0218] The rest is the same as in Example 21, except that the cobalt loading is 5% and the cerium loading is 3%. The activity evaluation results are shown in Table 27.

[0219] Table 27, Catalytic Activity in Example 22

[0220]

[0221]

[0222] Example 23

[0223] The rest is the same as in Example 21, except that the cobalt loading is 8% and the cerium loading is 5%, and the activity evaluation results are shown in Table 28.

[0224] Table 28, Catalytic Activity in Example 23

[0225] Propane oxidative dehydrogenation performance ％ propane conversion rate 51 propylene selectivity 70 propylene yield 35.7

[0226] Example 24

[0227] The rest is the same as in Example 21, except that the cobalt loading is 8% and the cerium loading is 7%, and the activity evaluation results are shown in Table 29.

[0228] Table 29, Catalytic Activity in Example 24

[0229] Propane oxidative dehydrogenation performance ％ propane conversion rate 51 propylene selectivity 69 propylene yield 35.2

[0230] Example 25

[0231] The rest is the same as in Example 21, except that the cobalt loading is 8% and the cerium loading is 8%. The activity evaluation results are shown in Table 30.

[0232] Table 30, Catalytic Activity in Example 25

[0233] Propane oxidative dehydrogenation performance ％ propane conversion rate 50 propylene selectivity 68 propylene yield 34.0

[0234] Example 26

[0235] The rest is the same as in Example 21, except that the cobalt loading is 0 and the cerium loading is 3%. The activity evaluation results are shown in Table 31.

[0236] Table 31, Catalytic Activity in Example 25

[0237] Propane oxidative dehydrogenation performance ％ propane conversion rate 43 propylene selectivity 69 propylene yield 29.7

[0238] Example 27

[0239] The rest is the same as in Example 21, except that the cobalt loading is 3% and the cerium loading is 0. The activity evaluation results are shown in Table 32.

[0240] Table 32, Catalytic Activity in Example 25

[0241] Propane oxidative dehydrogenation performance ％ propane conversion rate 41 propylene selectivity 67 propylene yield 27.5

[0242] As can be seen from Examples 21-25 and Examples 26-27, when platinum and cobalt are doped simultaneously in 3Pt-10In / Al2O3, the catalytic activity of the catalyst is greater than that of doping one of them alone or without doping.

[0243] Comparative Example 6

[0244] This comparative example uses boron nitride to compare the performance of the catalyst of the present invention in the oxidative dehydrogenation of propane to propylene. The specific steps are as follows:

[0245] 1) Weigh 300 mg of commercially available boron nitride (Alfa-Aesar) and place it in a steel tube in a fixed-bed reactor. Heat the mixture to 490 °C at a rate of 1 °C / min in a nitrogen atmosphere.

[0246] 2) After the temperature in step 1) stabilized, a reaction mixture was introduced. The gas composition was 4.3% propane by volume, 2.15% oxygen by volume, and the remainder nitrogen. The space velocity was 42 L / g / h. The reaction temperature was 490℃. After stabilizing for ten minutes, the products were analyzed using gas chromatography. The test results showed that the conversion rate of propane was 8.27%, and the selectivity for propylene was 85.9%.

[0247] Stability Examples

[0248] Example 28

[0249] The rest is the same as in Example 25, except that the reaction time is extended to 100 hours. The activity evaluation results are shown in Table 33.

[0250] Table 33, Catalytic Activity in Example 28

[0251] Propane oxidative dehydrogenation performance Initial activity % 100 hours of activity propane conversion rate 50 49.8 propylene selectivity 68 67.5 propylene yield 34.0 33.6

[0252] As can be seen from Table 33, the catalyst of the present invention has excellent stability. In the 100-hour stability test, the propylene yield did not decrease significantly.

[0253] The present invention has been described in detail above. For those skilled in the art, the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope, and without requiring unnecessary experiments. Although specific embodiments have been given, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including changes made using conventional techniques known in the art that depart from the scope disclosed herein. Some basic features can be applied according to the scope of the appended claims.

Claims

1. A method for catalytic oxidative dehydrogenation of propane to propylene, characterized in that, Includes the following steps: In the presence of oxygen and dilution gas, propane undergoes oxidative dehydrogenation in the presence of a propane oxidative dehydrogenation catalyst to yield propylene; The temperature for the oxidative dehydrogenation is 490°C; The propane oxidative dehydrogenation catalyst comprises an active component, a support, and an auxiliary agent. The active component and the auxiliary agent are supported on the support. The active component is a single Pt atom and a single In atom. The auxiliary agent comprises a first auxiliary agent and a second auxiliary agent, which are either: 1) the first auxiliary agent is palladium, and the second auxiliary agent is any one of ruthenium, cobalt, cerium, and copper; 2) the first auxiliary agent is cobalt, the second auxiliary agent is cerium, and the support is alumina. The active component Pt in the propane oxidative dehydrogenation catalyst has a mass percentage content of 1% to 5%; The active component In in the propane oxidative dehydrogenation catalyst has a mass percentage content of 3% to 15%; The preparation method of the propane oxidative dehydrogenation catalyst includes the following steps: (1) Add the precursors of Pt and In to the aqueous dispersion of alumina, and then stir, dry for the first time, calcine for the first time, and reduce at different temperature ranges in sequence; (2) The product obtained in step (1) is immersed in an aqueous solution of the precursor of the auxiliary agent, and then subjected to a second drying and a second calcination to obtain the propane oxidative dehydrogenation catalyst; The reduction at different temperature ranges was carried out in a 10% H2 atmosphere, and was carried out at 150℃, 200℃, 250℃ and 490℃ for 0.5 to 2 hours respectively.

2. The method for catalytic oxidative dehydrogenation of propane to propylene according to claim 1, characterized in that: The precursor of Pt is chloroplatinic acid; The precursor of In is indium nitrate; The concentration of alumina in the aqueous dispersion of alumina is 0.002~0.2 g / mL; The temperature for the first drying is 50~80℃, and the time is 8~12 hours; The first roasting temperature is 500~750℃, and the time is 1~3 hours; The first firing was carried out in an air atmosphere; The precursor of the auxiliary agent is the chloride, nitrate, sulfate or acetate of the auxiliary agent; The concentration of the precursor of the adjuvant in the aqueous solution of the precursor of the adjuvant is 0.02~0.04 g / ml; The second drying process takes place at a temperature of 50-80°C for 8-12 hours. The second roasting temperature is 150~450℃, and the time is 2~4 hours; The second roasting is carried out in an air atmosphere.

3. The method for catalytic oxidative dehydrogenation of propane to propylene according to claim 1, characterized in that: The propane oxidative dehydrogenation catalyst is heated to the oxidative dehydrogenation temperature under a reducing atmosphere; The reducing atmosphere consists of a reducing gas with a volume percentage of 1% to 10% and a balance gas. The balancing gas is nitrogen or argon; The reducing gas is hydrogen.

4. The method for catalytic oxidative dehydrogenation of propane to propylene according to claim 1 or 3, characterized in that: The volume percentage of propane in the reaction gas composed of propane, oxygen and dilution gas is 3% to 20%. The oxygen content in the reaction gas composed of the propane, the oxygen, and the dilution gas is 1.5% to 10% by volume. The dilution gas is nitrogen, helium, or argon. The space-time velocity of the propane oxidative dehydrogenation catalyst is 42~60 L / g / h, based on the amount of reaction gas passing through each gram of catalyst per unit time.

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