Method for catalyzing dehydrogenation reaction of n-butane

Abstract

The invention discloses a method for catalyzing dehydrogenation reaction of n-butane, which comprises the following steps: contacting and reacting a raw material containing n-butane and / or CO2 with a catalyst to obtain a product containing butene and butadiene, the catalyst comprises a carrier and an active component loaded on the carrier, the active component comprises an active component I and an active component II; the active component I is cobalt; the active component II is selected from at least one of manganese, molybdenum, tin, titanium, tungsten and aluminum; the carrier is silicalite-1 of pure silicon and / or silicalite-2 of pure silicon. The problems that an existing n-butane dehydrogenation catalyst is prone to sintering and carbon deposition are solved, and the catalyst prepared based on the method shows excellent butene and butadiene selectivity and catalytic stability in the n-butane dehydrogenation reaction and has good industrial application prospects.

Description

Technical Field

[0001] The present application relates to a method for catalyzing the dehydrogenation reaction of n-butane, and belongs to the field of nanomaterials and catalytic science. Background Art

[0002] In the context of carbon emission reduction, the added value and efficient utilization of low-carbon alkane resources have become particularly important and urgent. This application focuses on the high-value conversion of n-butane to produce key chemicals butene and butadiene. In view of the complex regeneration process of existing industrial platinum-based catalysts and the environmental pollution faced by chromium-based catalytic systems, it is particularly important to develop environmentally friendly and inexpensive transition metal catalysts. However, transition metal catalysts often face problems such as easy sintering and coking. Therefore, the design and preparation of transition metal catalysts with high activity, high olefin selectivity and high stability is the main challenge currently faced in the field of alkane dehydrogenation.

[0003] In view of the characteristics of cobalt-based catalysts such as low cost, environmental protection and high CH bond selective activation ability, highly dispersed and stable cobalt-based catalysts are prepared by organic-assisted thermal decomposition coupling of composite oxide precursors to solve the problems of easy sintering and coking of cobalt-based catalysts in the current n-butane dehydrogenation system.

[0004] Patents CN115920947A and CN114931968A have been applied for, both involving hydrothermal synthesis processes. The carriers used in patent CN111569937A are SAPO-34, 3A, 4A and 5A molecular sieves. Summary of the invention

[0005] The present application provides a supported cobalt-based catalyst, a preparation method and an application in the n-butane dehydrogenation reaction. The guest metal oxide that can form a composite oxide with the metal cobalt is used to strengthen the interaction between the metal cobalt and the guest metal oxide, thereby improving the anti-sintering ability of the cobalt species; the organic matter-assisted pyrolysis method is coupled to improve the dispersion of the metal cobalt, so that the catalyst exhibits excellent n-butane dehydrogenation activity, butene and butadiene selectivity and catalytic stability.

[0006] In this application, silicalite-1 and silicalite-2 are used as carriers, and highly dispersed and highly stable cobalt-based catalysts are prepared through organic-assisted pyrolysis and composite oxide precursors. The disclosed catalysts, preparation methods and applications thereof present different technical features and implementation effects from the above-mentioned applications.

[0007] According to one aspect of the present application, a method for catalyzing the dehydrogenation of n-butane is provided, the method comprising:

[0008] The raw material containing n-butane or the raw material containing n-butane and CO 2 The raw materials are contacted with a catalyst to react and obtain products containing butene and butadiene.

[0009] Optionally, the catalyst includes a carrier and an active component supported on the carrier.

[0010] Optionally, the active component includes an active component I and an active component II.

[0011] Optionally, the active component I is cobalt; and the active component II is selected from at least one of manganese, molybdenum, tin, titanium, tungsten and aluminum.

[0012] Optionally, the carrier is pure silicon silicalite-1 and / or silicalite-2.

[0013] Optionally, the cobalt content in the catalyst is 0.01 to 10 wt%, wherein the cobalt content is calculated based on the mass of the cobalt element.

[0014] Optionally, the cobalt content is independently selected from any value among 0.01wt%, 0.05wt%, 0.1wt%, 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt% or the range value between any two points above.

[0015] Optionally, in the catalyst, the content of active component II is 0.1 to 20 wt%, wherein the content of active component II is calculated based on the mass of the active component element.

[0016] Optionally, the content of the active component II is independently selected from any value among 0.1wt%, 0.5wt%, 1wt%, 5wt%, 10wt%, 15wt%, 20wt% or a range between any two of the above points.

[0017] Optionally, the method for preparing the catalyst comprises the following steps:

[0018] The catalyst is obtained by aging, drying and calcining a mixture containing cobalt salt, active component II precursor, auxiliary pyrolysis organic matter and a carrier.

[0019] Optionally, the auxiliary pyrolysis organic matter is selected from at least one of oxalic acid, citric acid, isopropanol, ethylenediamine, triethanolamine, and ascorbic acid.

[0020] Optionally, the auxiliary pyrolysis organic matter concentration is 0.01 to 5 mol / L.

[0021] Optionally, the auxiliary pyrolysis organic matter concentration is independently selected from any value among 0.01mol / L, 0.05mol / L, 0.1mol / L, 0.5mol / L, 1mol / L, 2mol / L, 3mol / L, 4mol / L, 5mol / L or a range value between any two of the above points.

[0022] Optionally, the molar ratio of the cobalt salt to the auxiliary pyrolysis organic matter is 100:1 to 1:10.

[0023] Optionally, the molar ratio of the cobalt salt to the auxiliary pyrolysis organic matter is independently selected from any value of 100:1, 90:1, 80:1, 70:1, 60:1, 50:1, 40:1, 30:1, 20:1, 10:1, 1:10 or a range between any two of the above points.

[0024] Optionally, the active component II precursor is selected from at least one of chlorides, nitrates, sulfates and organic esters of the active component II element.

[0025] Optionally, the concentration of the active component II precursor is 0.01 to 10 mol / L, calculated based on the molar amount of the active component II element of the active component II precursor.

[0026] Optionally, the concentration of the active component II precursor is independently selected from any value among 0.01mol / L, 0.05mol / L, 0.1mol / L, 0.5mol / L, 1mol / L, 2mol / L, 3mol / L, 4mol / L, 5mol / L, 6mol / L, 7mol / L, 8mol / L, 9mol / L, 10mol / L or a range value between any two of the above points.

[0027] Optionally, the molar ratio of the cobalt salt to the active component II precursor is 5:1 to 1:10.

[0028] Optionally, the molar ratio of the cobalt salt to the active component II precursor is independently selected from any value of 5:1, 4:1, 3:1, 2:1, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10 or a range between any two of the above points.

[0029] Optionally, the cobalt salt is selected from at least one of cobalt chloride, cobalt sulfate, cobalt nitrate and cobalt acetylacetonate.

[0030] Optionally, in the mixture, the concentration of the cobalt salt is 0.01 to 5 mol / L, calculated based on the molar amount of the cobalt element in the cobalt salt.

[0031] Optionally, the cobalt salt concentration is independently selected from any value among 0.01mol / L, 0.02mol / L, 0.04mol / L, 0.06mol / L, 0.08mol / L, 0.10mol / L, 0.50mol / L, 1mol / L, 2mol / L, 3mol / L, 4mol / L, 5mol / L or a range value between any two of the above points.

[0032] Optionally, the mass percentage of the carrier and the mixture is 30wt% to 70wt%.

[0033] Optionally, the mass percentage of the carrier and the mixture is independently selected from any value of 30wt%, 40wt%, 50wt%, 60wt%, 70wt% or a range between any two of the above points.

[0034] Optionally, the mixture further comprises a solvent.

[0035] Optionally, the solvent is selected from at least one of water, methanol and ethanol.

[0036] Optionally, the aging temperature is 10-80° C.; the aging time is 30-1200 min.

[0037] Optionally, the aging temperature is independently selected from any value of 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C or a range between any two of the above points.

[0038] Optionally, the aging time is independently selected from any value among 30min, 60min, 120min, 180min, 240min, 300min, 360min, 420min, 480min, 540min, 600min, 660min, 720min, 780min, 840min, 900min, 960min, 1020min, 1080min, 1140min, 1200min, or a range value between any two of the above points.

[0039] Optionally, the drying temperature is 50-200° C.; the drying time is 120-720 min.

[0040] Optionally, the drying temperature is independently selected from any value of 50°C, 60°C, 80°C, 100°C, 120°C, 140°C, 160°C, 180°C, 200°C or a range between any two of the above points.

[0041] Optionally, the drying time is independently selected from any value among 120 min, 180 min, 240 min, 300 min, 360 min, 420 min, 480 min, 540 min, 600 min, 660 min, 720 min or the range values between any two of the above.

[0042] Optionally, the roasting temperature is 400 - 700 °C; the roasting time is 30 - 360 min.

[0043] Optionally, the roasting temperature is independently selected from any value among 400 °C, 450 °C, 500 °C, 550 °C, 600 °C, 650 °C, 700 °C or the range values between any two of the above.

[0044] Optionally, the roasting time is independently selected from any value among 30 min, 60 min, 120 min, 180 min, 240 min, 300 min, 360 min or the range values between any two of the above.

[0045] Optionally, the reaction temperature is 500 - 650 °C; the reaction pressure is 0.1 - 1.0 MPa.

[0046] Optionally, the reaction temperature is independently selected from any value among 500 °C, 550 °C, 600 °C, 650 °C or the range values between any two of the above.

[0047] Optionally, the reaction pressure is independently selected from any value among 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, 1 MPa or the range values between any two of the above.

[0048] Optionally, the CO 2 to n-butane volume ratio is 1:10 - 10:1; the mass space velocity of n-butane is 0.05 - 10.00 h -1 .

[0049] Optionally, the CO 2 to n-butane volume ratio is independently selected from any value among 1:10, 1:8, 1:6, 1:4, 1:2, 1:1, 2:1, 4:1, 6:1, 8:1, 10:1 or the range values between any two of the above.

[0050] Optionally, the mass space velocity of n-butane is independently selected from 0.05 h -1 , 0.1 h -1 , 0.5 h -1 , 1 h -1 , 2 h -1, 3h -1 , 4h -1 , 5h -1 , 6h -1 , 7h -1 , 8h -1 , 9h -1 , 10h -1 Any value in or a range of values ​​between any two of the above points.

[0051] As an optional technical solution, the preparation of the catalyst of the present application is achieved by the following technical solution:

[0052] The specific preparation method comprises the following steps:

[0053] (1) dissolving precursors corresponding to cobalt salt and metal oxide in a solvent to prepare a uniform solution;

[0054] (2) adding the organic matter into (1) and stirring to obtain a uniform impregnation solution;

[0055] (3) adding the carrier to (2) and stirring evenly, and aging the mixture at a certain temperature for a certain period of time;

[0056] (4) drying the mixture obtained in (3) at a certain temperature for a certain period of time, and crushing the dried sample;

[0057] (5) The powder sample obtained in (4) is calcined at a certain temperature to obtain the final catalyst.

[0058] Optionally, the metal oxide includes at least one of manganese oxide, molybdenum oxide, tin oxide, titanium oxide, tungsten oxide, and aluminum oxide.

[0059] Optionally, the organic matter includes at least one of oxalic acid, citric acid, isopropyl alcohol, ethylenediamine, triethanolamine, and ascorbic acid.

[0060] The present application solves the problem of easy sintering and carbon deposition of the current n-butane dehydrogenation catalyst. The catalyst provided in the present application and its preparation method, wherein the organic matter-assisted thermal decomposition of the metal cobalt salt coupled with the composite oxide precursor can obtain a cobalt-based catalyst that is resistant to sintering and coking. The catalyst includes a carrier and active metal cobalt and metal oxide supported on the carrier, and the carrier is pure silicon silicalite-1 and / or silicalite-2. The catalyst prepared based on the present application shows excellent butene and butadiene selectivity and catalytic stability in the n-butane dehydrogenation reaction, and has good prospects for industrial application.

[0061] The beneficial effects of this application include:

[0062] 1) The catalyst provided in the present application is a cobalt-based catalyst prepared by organic-assisted thermal decomposition of a coupled composite oxide precursor and has good dispersibility and catalytic stability.

[0063] 2) This application mainly solves the problem of easy sintering and carbon deposition of active metal components in the current n-butane dehydrogenation system. The cobalt-based catalyst prepared by this method shows excellent catalytic performance in the catalytic n-butane dehydrogenation reaction, and the n-butane conversion rate, C4 olefin selectivity and catalytic stability are better than those of traditional supported cobalt-based catalysts. Under the conditions of 500-650°C and 0.1-1.0MPa, the n-butane single-pass conversion rate is greater than 20%, and the C4 olefin selectivity can reach more than 95%. The preparation method disclosed in this application has the characteristics of simple operation and good repeatability, and can be used for industrial applications of n-butane dehydrogenation reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 This is a scanning electron microscope photograph of the sample of Example 1 of the present application, with a scale of 100 nm. DETAILED DESCRIPTION

[0065] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0066] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0067] The present invention uses a flame ionization detector (FID) to analyze hydrocarbon products in the product; a thermal conductivity detector (TCD) to analyze H 2 , CO, CH 4 and CO 2 ;

[0068] The morphology and size of the samples were characterized by a Hitachi SU1510 scanning electron microscope (low magnification, accelerating voltage: 15 kV). Before testing, the powder samples were glued to conductive tape and gold-sprayed.

[0069] The conversion rate and selectivity calculation formulas in the examples of this application are as follows:

[0070]

[0071]

[0072] Example 1

[0073] First, 0.2469 g of Co(NO 3 ) 2 6H 2 O and 0.0950 g SnCl 2 ·2H 2O was dissolved in 3g of ethanol, and then 0.01g of isopropanol was added and stirred evenly. 5g of pure silicalite-1 (S-1) carrier was added and stirred evenly, and then ethanol was added until adsorption was saturated. The mixture was aged at 25℃ for 16h, and then dried at 80℃ for 360min. The dried sample was ground and crushed. After calcination at 400℃ for 360min, the temperature was raised to 600℃ and continued to be calcined for 30min to finally obtain CoSnO x / S-1 catalyst.

[0074] Figure 1 This is a scanning electron microscope photo of the sample of Example 1. Figure 1 It can be seen that CoSnO x / S-1 catalyst is supported by plate-like cross-linked silicalite-1 with a particle size of 450nm, and the guest components in the catalyst have good dispersion.

[0075] Example 2

[0076] First, 0.2469 g of Co(NO 3 ) 2 6H 2 O and 0.1042 g of Al(NO 3 ) 3 9H 2 O was dissolved in 3g water, and then 0.0102g ethylenediamine was added and stirred evenly. 5g pure silicalite-1 (S-1) carrier was added and stirred evenly, and then water was added until adsorption was saturated, aged at 25℃ for 16h, and then dried at 80℃ for 360min. The dried sample was ground and crushed. After calcination at 400℃ for 360min, the temperature was raised to 600℃ and continued to be calcined for 30min, and finally CoAlO was obtained. x / S-1 catalyst.

[0077] Example 3

[0078] First, 0.2469 g of Co(NO 3 ) 2 6H 2 O and 0.0153 g (NH 4 ) 2 MoO 4 Dissolve in 3g water, add 0.0253g triethanolamine and stir evenly. Add 5g pure silicalite-1 (S-1) carrier and stir evenly, then add water to adsorption saturation, age at 25℃ for 16h, then dry at 80℃ for 360min, grind and crush the dried sample. After calcination at 400℃ for 360min, heat to 600℃ and continue calcination for 30min, finally obtain CoMoO x / S-1 catalyst.

[0079] Example 4

[0080] First, 0.2469 g of Co(NO 3 ) 2 6H 2 O and 0.0533g of tetrabutyl titanate were dissolved in 3g of ethanol, and then 0.0102g of isopropanol was added and stirred evenly. 5g of pure silicalite-1 (S-1) carrier was added and stirred evenly, and then ethanol was added until adsorption was saturated. The mixture was aged at 25℃ for 16h, and then dried at 80℃ for 360min. The dried sample was ground and crushed. After calcination at 400℃ for 360min, the temperature was raised to 600℃ and calcined for 30min to finally obtain CoTiO x / S-1 catalyst.

[0081] Example 5

[0082] First, 0.2469 g of Co(NO 3 ) 2 6H 2 O and 0.0135 g of Na 2 (WO 4 )·2H 2 O was dissolved in 3g water, and then 0.0153g oxalic acid was added and stirred evenly. 5g pure silicalite-1 (S-1) carrier was added and stirred evenly, and then water was added until adsorption was saturated, aged at 25℃ for 16h, and then dried at 80℃ for 360min. The dried sample was ground and crushed. After calcination at 400℃ for 360min, the temperature was raised to 600℃ and continued to be calcined for 30min, and finally CoWO was obtained. x / S-1 catalyst.

[0083] Comparative Example 1

[0084] First, 0.2469 g of Co(NO 3 ) 2 6H 2 O was dissolved in 3g of ethanol, 5g of pure silicon S-1 carrier was added and stirred evenly, and then ethanol was added until adsorption was saturated, aged at 25℃ for 16h, and then dried at 80℃ for 360min. The dried sample was ground and crushed. After calcination at 400℃ for 360min, the temperature was raised to 600℃ and calcined for 30min, and finally the Co / S-1 catalyst was obtained.

[0085] Test Example 1

[0086] The test process is as follows: the catalysts of the examples and comparative examples are loaded into a fixed bed reactor lined with a quartz tube, and heated to the reaction temperature at a heating rate of 10°C / min in a nitrogen atmosphere (12 mL / min). 2 / CO 2 / nC 4 H10 (9600mL / (g·h)) reaction atmosphere, n-butane mass space velocity is 0.62h -1 , CO 2 / nC 4 H 10 =10:1, pressure 0.1MPa. The reaction product is heated and vaporized and then sent to gas chromatography for analysis. TCD is used to analyze H 2 , CO, CH 4 and CO 2 The FID was used to analyze hydrocarbon products. The specific test results are shown in Table 1.

[0087] Table 1 shows the performance of the examples and comparative samples at 530°C and 590°C. x / S-1, CoAlO x / S-1、CoMoO x / S-1 and CoTiO x The activity of the CoSnO / S-1 samples was improved to varying degrees. x The n-butane conversion rate of CoSnO / S-1 is significantly higher than that of CoS-1 (59% vs 34%), and the selectivity of C4 olefins (monoolefins and butadiene) in hydrocarbon products is also higher than that of CoS-1 (90.6% vs 86.3%). x The excellent performance of / S-1 is mainly attributed to the fact that the guest tin oxide inhibits the aggregation and sintering of metallic cobalt, that is, it slows down the deactivation rate of the catalyst and reduces the side reactions such as cracking caused by the aggregation of metallic cobalt.

[0088] Table 1

[0089]

[0090]

[0091] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for catalyzing the dehydrogenation of n-butane, It is characterized in that The method comprises: The raw material containing n-butane or the raw material containing n-butane and CO 2 The raw materials are contacted with a catalyst to react and obtain products containing butene and butadiene.

2. The method according to claim 1, It is characterized in that The catalyst comprises a carrier and an active component supported on the carrier; Preferably, the active component comprises active component I and active component II; Preferably, the active component I is cobalt; the active component II is selected from at least one of manganese, molybdenum, tin, titanium, tungsten and aluminum; Preferably, the carrier is pure silicon silicalite-1 and / or silicalite-2; Preferably, the cobalt content in the catalyst is 0.01 to 10 wt%, wherein the cobalt content is calculated based on the mass of the cobalt element; Preferably, in the catalyst, the content of active component II is 0.1-20 wt%, wherein the content of active component II is calculated based on the mass of the active component element.

3. The method according to claim 1, It is characterized in that The preparation method of the catalyst comprises the following steps: The catalyst is obtained by aging, drying and calcining a mixture containing cobalt salt, active component II precursor, auxiliary pyrolysis organic matter and a carrier.

4. The method according to claim 3, It is characterized in that The auxiliary pyrolysis organic matter is selected from at least one of oxalic acid, citric acid, isopropanol, ethylenediamine, triethanolamine, and ascorbic acid; Preferably, the concentration of the auxiliary pyrolysis organic matter is 0.01 to 5 mol / L; Preferably, the molar ratio of the cobalt salt to the auxiliary pyrolysis organic matter is 100:1 to 1:

10.

5. The method according to claim 3, It is characterized in that The active component II precursor is selected from at least one of the chloride, nitrate, sulfate, and organic ester of the active component II element; Preferably, the concentration of the active component II precursor is 0.01 to 10 mol / L, calculated as the molar amount of the active component II element of the active component II precursor; Preferably, the molar ratio of the cobalt salt to the active component II precursor is 5:1 to 1:10; Preferably, the cobalt salt is selected from at least one of cobalt chloride, cobalt sulfate, cobalt nitrate and cobalt acetylacetonate; Preferably, in the mixture, the concentration of the cobalt salt is 0.01 to 5 mol / L, calculated based on the molar amount of the cobalt element in the cobalt salt.

6. The method according to claim 3, It is characterized in that The mass percentage of the carrier and the mixture is 30wt% to 70wt%; Preferably, the mixture further comprises a solvent; Preferably, the solvent is selected from at least one of water, methanol and ethanol.

7. The method according to claim 3, It is characterized in that The aging temperature is 10-80°C; the aging time is 30-1200 minutes; Preferably, the drying temperature is 50-200° C.; and the drying time is 120-720 min.

8. The method according to claim 3, It is characterized in that The calcination temperature is 400-700° C. and the calcination time is 30-360 minutes.

9. The method according to claim 1, It is characterized in that The reaction temperature is 500-650° C.; the reaction pressure is 0.1-1.0 MPa.

10. The method according to claim 1, It is characterized in that The CO 2 The volume ratio of n-butane is 1:10 to 10:1; the mass space velocity of n-butane is 0.05 to 10.00 h -1 .

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