Octahedral iron oxide nano-particle catalyst with concave surface, preparation method thereof and application of octahedral iron oxide nano-particle catalyst in preparation of long-chain olefin
By using an octahedral ferrite nanoparticle catalyst with a recessed surface, linear α olefins are efficiently prepared in the carbon dioxide hydrogenation reaction, and the problem of lack of high-efficiency catalysts in the prior art is solved, and the effects of high catalytic activity and selectivity are achieved.
Patent Information
- Application Number
- CN202411621726.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-13
- Publication Date
- 2025-02-14
AI Technical Summary
The prior art lacks a catalyst that can efficiently catalyze the hydrogenation of carbon dioxide to prepare linear alpha olefins (α-C4+=), especially olefins in the C2-4= gaseous range.
A catalyst with high catalytic activity and selectivity was prepared by mixing iron, manganese, and surfactant to nucleate under high temperature conditions using an octahedral ferrite nanoparticle catalyst with a recessed surface.
In the reaction to prepare linear alpha olefins with hydrogenation of carbon dioxide, the catalyst showed high catalytic activity and selectivity, with a carbon dioxide conversion rate of up to 49.6%, and a C4+olefin selectivity of 63.7%, of which linear alpha olefins accounted for 89.0%.
Smart Images
Figure CN119425720A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of catalysts, and in particular to an octahedral iron oxide nanoparticle catalyst with a concave surface, a preparation method thereof and an application thereof in preparing long-chain olefins. Background Art
[0002] With the extensive use of fossil energy, carbon dioxide is emitted in large quantities, causing a series of environmental problems. However, scientists have found that carbon dioxide, especially high-purity carbon dioxide obtained from industries such as cement manufacturing, beer production and fuel processing, can be used as raw materials to replace fossil resources to produce high-value chemicals, thereby generating higher environmental benefits and economic value.
[0003] Linear alpha olefins (α-C 4+ = ) are common industrial raw materials for a variety of value-added products, such as synthetic high-end lubricants, biodegradable detergents, new polymers, agrochemicals, coatings and corrosion inhibitors. The common method for synthesizing these olefins is based on the oligomerization of ethylene, which is mainly obtained from petroleum resources. 4+ = It can be obtained directly from CO2 hydrogenation, so using α-C 4+ = As an industrial raw material, it will play a key role in the sustainable development of society. In the context of tight global energy prices, it can play an important role in helping related industries get rid of their dependence on fossil energy. At present, olefins produced by CO2 hydrogenation are mainly produced in C 2-4 = In the gaseous range, the corresponding catalysts usually include metal oxides for methanol synthesis and zeolite catalysts for methanol to olefins. 4+ = catalyst.
[0004] Therefore, the production of α-C by CO2 hydrogenation is realized. 4+ = It is still a huge challenge to provide a high-quality CO2 hydrogenation to produce α-C 4+ = Catalysts and methods for their preparation are highly desirable. Summary of the invention
[0005] In view of this, the technical problem to be solved by the present invention is to provide an octahedral iron oxide nanoparticle catalyst with a concave surface, a preparation method thereof and an application thereof in preparing long-chain olefins. The prepared octahedral iron oxide nanoparticle catalyst with a concave surface has high catalytic activity in the reaction of hydrogenating carbon dioxide to prepare linear alpha olefins.
[0006] The present invention provides a method for preparing an octahedral iron oxide nanoparticle catalyst having a concave surface, comprising the following steps:
[0007] The iron source, manganese source and surfactant are mixed, nucleated under high temperature conditions, and octahedral iron oxide nanoparticle catalysts with concave surfaces are obtained after cooling.
[0008] Preferably, the nucleation under high temperature conditions specifically comprises the following steps:
[0009] Heating a mixture of an iron source, a manganese source, and a surfactant to a first temperature and keeping the temperature for a first time, and then heating the mixture to a second temperature and keeping the temperature for a second time to obtain a second mixture;
[0010] heating the second mixture to a third temperature and maintaining the temperature for a third time to complete nucleation;
[0011] The first temperature is 100-140°C;
[0012] The second temperature is 180-220°C;
[0013] The third temperature is 290-310°C.
[0014] Preferably, the heating rate of heating to the first temperature is 5-15°C / min;
[0015] The heating rate of heating to the second temperature is 5-15°C / min;
[0016] The heating rate of heating to the third temperature is 5-15°C / min.
[0017] Preferably, the first time is 50 to 70 minutes;
[0018] The second time is 50-70 minutes;
[0019] The third time is 50 to 70 minutes.
[0020] Preferably, the iron source is selected from ferric acetylacetonate;
[0021] The manganese source is selected from manganese acetate tetrahydrate;
[0022] The surfactants include oleic acid and oleylamine.
[0023] Preferably, the ratio of the iron source, manganese source and surfactant is (0.4-0.6) g: (0.05-0.15) g: (8-12) mL.
[0024] Preferably, the cooling further comprises a step of using acetone for precipitation;
[0025] The step of using acetone to precipitate also includes a step of using n-hexane to wash;
[0026] The total mass ratio of the acetone to the iron source and the manganese source is 50-200 mL / g;
[0027] The total mass ratio of the n-hexane to the iron source and the manganese source is 100-300 mL / g.
[0028] The invention provides an octahedral iron oxide nanoparticle catalyst with a concave surface prepared by the preparation method.
[0029] The present invention provides the use of an octahedral iron oxide nanoparticle catalyst with a concave surface prepared by the preparation method as a catalyst for preparing a long-chain olefin reaction.
[0030] Compared with the prior art, the present invention provides an octahedral iron oxide nanoparticle catalyst with a concave surface, which has the advantages of good catalytic activity and high selectivity in the reaction of preparing linear alpha olefins by hydrogenation of carbon dioxide; in the process of carbon dioxide hydrogenation, the optimal conversion rate is as high as 49.6%, C 4+ The olefin selectivity can reach 63.7% in the produced hydrocarbons, of which linear alpha olefins account for 89.0%. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Figure 1 TEM image of the octahedral iron oxide nanoparticle catalyst with a concave surface prepared in Example 1;
[0032] Figure 2 TEM image of the octahedral iron oxide nanoparticle catalyst with a concave surface prepared in Example 2;
[0033] Figure 3 TEM image of the octahedral iron oxide nanoparticle catalyst with a concave surface prepared in Example 3;
[0034] Figure 4 TEM image of the iron-oxygen irregular small particle catalyst prepared in Comparative Example 1;
[0035] Figure 5 This is the TEM image of the iron oxide cubic catalyst prepared in Comparative Example 2. DETAILED DESCRIPTION
[0036] The present invention provides a method for preparing an octahedral iron oxide nanoparticle catalyst having a concave surface, comprising the following steps:
[0037] The iron source, manganese source and surfactant are mixed, nucleated under high temperature conditions, and octahedral iron oxide nanoparticle catalysts with concave surfaces are obtained after cooling.
[0038] Preferably, the iron source is selected from ferric acetylacetonate.
[0039] Preferably, the manganese source is selected from manganese acetate tetrahydrate.
[0040] Preferably, the surfactant comprises oleic acid and oleylamine.
[0041] Preferably, the ratio of the iron source, manganese source and surfactant is (0.4-0.6) g: (0.05-0.15) g: (8-12) mL.
[0042] In the surfactant, the volume ratio of the oleic acid to the oleylamine is preferably 1:(0.5-1.5).
[0043] Preferably, the ratio of the iron source, manganese source, oleic acid and oleylamine is (0.4~0.6) g: (0.05~0.15) g: (4~6) mL: (4~6) mL; in some specific embodiments of the present invention, the ratio is 0.5g:0.1g:4mL:6mL, 0.5g:0.1g:5mL:5mL, 0.5g:0.1g:6mL:4mL, 0.6g:0.1g:4mL:6mL, 0.4g:0.1g:4mL:6mL, etc.
[0044] Preferably, after the iron source, manganese source and surfactant are mixed, the mixture is firstly subjected to impurity removal. Preferably, the impurities are removed by passing nitrogen at high temperature. The temperature of the nitrogen is preferably 100-140°C.
[0045] Preferably, the nucleation under high temperature conditions specifically comprises the following steps:
[0046] Heating a mixture of an iron source, a manganese source, and a surfactant to a first temperature and keeping the temperature for a first time, and then heating the mixture to a second temperature and keeping the temperature for a second time to obtain a second mixture;
[0047] The second mixture is heated to a third temperature and maintained at the third temperature for a third time to complete nucleation.
[0048] The first temperature is preferably 100-140°C; more preferably 110-130°C, and further preferably 120°C.
[0049] The first time is preferably 50 to 70 min; more preferably 55 to 65 min, and further preferably 60 min.
[0050] The heating rate for heating to the first temperature is preferably 5-15° C. / min, more preferably 8-12° C. / min, and further preferably 10° C. / min.
[0051] The heating to the first temperature is preferably uniform heating.
[0052] The second temperature is preferably 180-220°C, more preferably 190-210°C, and further preferably 200°C.
[0053] The second time is preferably 50 to 70 min; more preferably 55 to 65 min, and even more preferably 60 min.
[0054] The heating rate for heating to the second temperature is preferably 5-15° C. / min, more preferably 8-12° C. / min, and further preferably 10° C. / min.
[0055] The heating to the second temperature is preferably performed at a uniform speed.
[0056] The third temperature is preferably 290-310°C, and more preferably 300°C.
[0057] The third time is preferably 50 to 70 min; more preferably 55 to 65 min, and even more preferably 60 min.
[0058] The heating rate for heating to the third temperature is preferably 5-15° C. / min, more preferably 8-12° C. / min, and further preferably 10° C. / min.
[0059] The heating to the third temperature is preferably performed by heating at a uniform speed.
[0060] The cooling is preferably cooling to room temperature.
[0061] Preferably, the step of using acetone to precipitate is further included after cooling.
[0062] Preferably, the total mass ratio of the acetone to the iron source and the manganese source is 50-200 mL / g, more preferably 50-100 mL / g.
[0063] Preferably, the step of precipitating with acetone further includes a step of washing with n-hexane.
[0064] Preferably, the total mass ratio of the n-hexane to the iron source and the manganese source is 100-300 mL / g, more preferably 200-300 mL / g.
[0065] The invention provides an octahedral iron oxide nanoparticle catalyst with a concave surface prepared by the preparation method.
[0066] The iron oxide nanoparticle catalyst provided by the present invention has an octahedral configuration, and each face of the octahedron is concave so that the cross section of the octahedron is in the shape of a four-pointed star. The iron oxide nanoparticle catalyst is in the shape of a four-pointed star fruit as a whole.
[0067] The present invention provides the use of an octahedral iron oxide nanoparticle catalyst with a concave surface prepared by the preparation method as a catalyst for preparing a long-chain olefin reaction.
[0068] The invention provides a reaction for preparing linear alpha olefins by hydrogenating carbon dioxide, using octahedral iron oxide nanoparticles with a concave surface prepared by the preparation method as a catalyst.
[0069] Preferably, the reaction of hydrogenating carbon dioxide to produce linear alpha olefins is carried out in a fixed bed reactor.
[0070] The reaction pressure is preferably 20 bar and the temperature is preferably 340°C.
[0071] The catalyst is preferably loaded into a fixed bed reactor with an inner diameter of 9 mm. Subsequently, a 20 bar reaction gas (72 vol% H2, 24 vol% CO2 and 4 vol% Ar, with Ar as an internal standard) is used as the feed gas at a rate of 20 mL min -1 The gas flow rate is introduced into the fixed bed reactor.
[0072] The amount of the catalyst used is preferably 100 mg.
[0073] In the present embodiment, two gas chromatographs are used to detect products and reactants online, and H2, CO, CO2, CH4 and Ar are analyzed by a carbon molecular sieve column (TDX-1) with a thermal conductivity detector (TCD); a PONA capillary column with a flame ionization detector (FID) is used to analyze carbon hydrogen compounds, and CH4 is used as a reference bridge between TCD and FID. Assuming that the amount of Ar remains constant after the reaction, the CO2 conversion rate is calculated according to the internal standard method.
[0074] The CO2 conversion rate is calculated based on carbon atoms using the following formula:
[0075] CO2 conversion rate = (CO 2 inlet -CO 2 outlet ) / CO 2 inlet ×100%;
[0076] Among them, CO 2 inlet and CO 2 outlet are the moles of CO2 at the inlet and outlet, respectively.
[0077] Hydrocarbon C n H m The selectivity is calculated according to the following formula:
[0078] ;
[0079] Among them, C n H m outletrepresents the number of moles of a single hydrocarbon product at the outlet; the denominator represents the total number of moles of carbon atoms in all hydrocarbon products at the outlet, and m, n, i and j are the number of carbon and hydrogen. The selectivity of oxygenated compounds is less than 1.0%; the carbon balance exceeds 94.0%.
[0080] The test results show that the catalyst provided by the present invention has the advantages of good catalytic activity and high selectivity in the reaction of preparing linear alpha olefins by hydrogenation of carbon dioxide, and the carbon dioxide conversion rate is as high as 47%. 4+ The olefin selectivity in the produced hydrocarbons can reach more than 60%, of which linear alpha olefins account for more than 85%.
[0081] In order to further illustrate the present invention, the following is a detailed description in conjunction with the embodiments. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the invention.
[0082] All raw materials of the present invention have no particular limitation on their sources, and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.
[0083] Example 1
[0084] Octahedral iron oxide nanoparticle catalysts with concave surfaces are prepared as follows:
[0085] First, 0.5 g of ferric acetylacetonate, 0.1 g of manganese acetate tetrahydrate, 5 mL of oleic acid, and 5 mL of oleylamine were mixed at room temperature, nitrogen was introduced, and the mixture was heated to 120 °C at a heating rate of 10 °C / min, kept at this temperature for 60 min, and then heated to 200 °C at a heating rate of 10 °C / min. o C and hold for 60 min, then heat to 300 at a rate of 10°C / min. o C and kept for 60 minutes. After cooling naturally to room temperature, 100 mL of acetone was added, centrifuged at 8000 rpm / min for 10 minutes, and then washed three times with 100 mL of n-hexane. The product was collected and dried to obtain an octahedral iron oxide nanoparticle catalyst with a concave surface.
[0086] Figure 1 This is the TEM image of the catalyst prepared in Example 1.
[0087] like Figure 1 As shown, the characterization results show that the present invention prepares an octahedral iron oxide catalyst with a concave surface.
[0088] The prepared catalyst was tested for its carbon dioxide hydrogenation performance:
[0089] 100 mg of the prepared catalyst was loaded into a fixed bed, and a mixture of carbon dioxide and hydrogen was introduced. The mixture contained 4% argon as an internal standard for calculating the conversion rate and selectivity. The volume ratio of carbon dioxide to hydrogen in the mixture was 1:3. A continuous reaction was carried out under the reaction conditions of 340°C, 20 bar, and 20 mL / min. The reaction tail gas passed through a fully insulated needle valve and a heating pipe and entered the gas chromatograph for online analysis. After 20 hours of reaction, the carbon dioxide conversion rate was as high as 49.6%. At the same time, the C 4+ The olefin selectivity can reach 63.7% in the produced hydrocarbons, of which linear alpha olefins account for 89.0%.
[0090] Example 2
[0091] The difference from Example 1 is that the amounts of oleic acid and oleylamine added are 4 mL and 6 mL respectively.
[0092] The prepared catalyst was tested for its carbon dioxide hydrogenation performance:
[0093] 100 mg of the prepared catalyst was loaded into a fixed bed, and a mixture of carbon dioxide and hydrogen was introduced. The mixture contained 4% argon as an internal standard for calculating the conversion rate and selectivity. The volume ratio of carbon dioxide to hydrogen in the mixture was 1:3. A continuous reaction was carried out under the reaction conditions of 340°C, 20 bar, and 20 mL / min. The reaction tail gas passed through a fully insulated needle valve and a heating pipe and entered the gas chromatograph for online analysis. After 20 hours of reaction, the carbon dioxide conversion rate was 47.3%. At the same time, the C 4+ The olefin selectivity can reach 60.2% in the produced hydrocarbons, of which linear alpha olefins account for 85.4%.
[0094] Figure 2 This is the TEM image of the catalyst prepared in Example 2.
[0095] Example 3
[0096] The difference from Example 1 is that the amounts of iron acetylacetonate and manganese acetate tetrahydrate added are 0.6 g and 0.15 g respectively.
[0097] The prepared catalyst was tested for its carbon dioxide hydrogenation performance:
[0098] 100 mg of the prepared catalyst was loaded into a fixed bed, and a mixture of carbon dioxide and hydrogen was introduced. The mixture contained 4% argon as an internal standard for calculating the conversion rate and selectivity. The volume ratio of carbon dioxide to hydrogen in the mixture was 1:3. A continuous reaction was carried out under the reaction conditions of 340°C, 20 bar, and 20 mL / min. The reaction tail gas passed through a fully insulated needle valve and a heating pipeline and entered the gas chromatograph for online analysis. After 20 hours of reaction, the carbon dioxide conversion rate was 48.5%. At the same time, the C 4+ The olefin selectivity can reach 62.3% in the produced hydrocarbons, of which linear alpha olefins account for 88.6%.
[0099] Figure 3 This is the TEM image of the catalyst prepared in Example 3.
[0100] Comparative Example 1
[0101] The preparation method of irregular small iron oxide particles is as follows:
[0102] First, 0.5 g of ferric acetylacetonate, 0.1 g of manganese acetate tetrahydrate, 5 mL of oleic acid, and 5 mL of oleylamine were mixed at room temperature, nitrogen was introduced, and the mixture was heated to 120 °C at a heating rate of 10 °C / min, kept at this temperature for 60 min, and then heated to 200 °C at a heating rate of 10 °C / min. o C and hold for 60 min, then heat to 280 at a rate of 10°C / min. o C and kept for 60 min. After cooling naturally to room temperature, 100 mL of acetone was added, centrifuged at 8000 rpm / min for 10 min, and then washed three times with 100 mL of n-hexane. The product was collected and dried to obtain irregular small iron oxide particles.
[0103] Figure 4 This is the TEM image of the iron oxide irregular small particle catalyst prepared in Comparative Example 1.
[0104] 100 mg of the prepared iron oxide irregular small particles were loaded into a fixed bed, and a mixture of carbon dioxide and hydrogen was introduced. The mixture contained 4% argon as an internal standard for calculating the conversion rate and selectivity. The volume ratio of carbon dioxide to hydrogen in the mixture was 1:3. The reaction was carried out continuously under the reaction conditions of 340°C, 20 bar, and 20 mL / min. The reaction tail gas passed through a fully insulated needle valve and a heating pipe and entered the gas chromatograph for online analysis. After 20 hours of reaction, the carbon dioxide conversion rate was 23.7%. At the same time, the C 4+ The olefin selectivity was 46.3% among the hydrocarbons produced, of which linear alpha olefins accounted for 55.4%.
[0105] Comparative Example 2
[0106] Prepare ferrite cubes as follows:
[0107] First, 0.5 g of ferric acetylacetonate, 0.1 g of manganese acetate tetrahydrate, 5 mL of oleic acid, and 5 mL of oleylamine were mixed at room temperature, nitrogen was introduced, and the mixture was heated to 120 °C at a heating rate of 10 °C / min, kept at this temperature for 60 min, and then heated to 200 °C at a heating rate of 10 °C / min. o C and hold for 60 min, then heat to 300 at a rate of 10°C / min. o C and kept for 120 min. After cooling naturally to room temperature, 100 mL of acetone was added, centrifuged at 8000 rpm / min for 10 min, and then washed three times with 100 mL of n-hexane. The product was collected and dried to obtain iron oxide cubes.
[0108] Figure 5 This is the TEM image of the iron oxide cubic catalyst prepared in Comparative Example 2.
[0109] 100 mg of the prepared iron oxide cubes were loaded into a fixed bed, and a mixture of carbon dioxide and hydrogen was introduced. The mixture contained 4% argon as an internal standard for calculating the conversion rate and selectivity. The volume ratio of carbon dioxide to hydrogen in the mixture was 1:3. The reaction was carried out continuously under the reaction conditions of 340°C, 20 bar, and 20 mL / min. The reaction tail gas passed through a fully insulated needle valve and a heating pipe and entered the gas chromatograph for online analysis. After 20 hours of reaction, the carbon dioxide conversion rate was 45.7%. At the same time, the C 4+ The olefin selectivity was 53.3% among the hydrocarbons produced, of which linear alpha olefins accounted for 67.2%.
[0110] The above results indicate that the octahedral iron oxide nanoparticle catalyst with a concave surface provided by the present invention has the advantages of a short preparation cycle, uniform distribution of the two components, and uniform size. The catalyst is applied to the preparation of linear alpha olefins by hydrogenation of carbon dioxide, has excellent performance, good catalytic activity, and high selectivity for the target product, and has prospects for industrial application.
[0111] The above embodiments are only used to help understand the method and core idea of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.
Claims
1. A method for preparing an octahedral iron oxide nanoparticle catalyst having a concave surface, comprising the following steps: The iron source, manganese source and surfactant are mixed, nucleated under high temperature conditions, and octahedral iron oxide nanoparticle catalysts with concave surfaces are obtained after cooling.
2. The preparation method according to claim 1, characterized in that: The nucleation under high temperature conditions specifically comprises the following steps: Heating a mixture of an iron source, a manganese source, and a surfactant to a first temperature and keeping the temperature for a first time, and then heating the mixture to a second temperature and keeping the temperature for a second time to obtain a second mixture; heating the second mixture to a third temperature and maintaining the temperature for a third time to complete nucleation; The first temperature is 100-140°C; The second temperature is 180-220°C; The third temperature is 290-310°C.
3. The preparation method according to claim 2, characterized in that: The heating rate of heating to the first temperature is 5-15°C / min; The heating rate of heating to the second temperature is 5-15°C / min; The heating rate of heating to the third temperature is 5-15°C / min.
4. The preparation method according to claim 2, characterized in that: The first time is 50-70 minutes; The second time is 50-70 minutes; The third time is 50 to 70 minutes.
5. The preparation method according to claim 1, characterized in that: The iron source is selected from ferric acetylacetonate; The manganese source is selected from manganese acetate tetrahydrate; The surfactants include oleic acid and oleylamine.
6. The preparation method according to claim 1, characterized in that: The ratio of the iron source, manganese source and surfactant is (0.4-0.6) g: (0.05-0.15) g: (8-12) mL.
7. The preparation method according to claim 1, characterized in that: The cooling step further includes a step of using acetone for precipitation; The step of using acetone to precipitate also includes a step of using n-hexane to wash; The total mass ratio of the acetone to the iron source and the manganese source is 50-200 mL / g; The total mass ratio of the n-hexane to the iron source and the manganese source is 100-300 mL / g.
8. Octahedral iron oxide nanoparticle catalyst with a concave surface prepared by the preparation method according to any one of claims 1 to 7.
9. Use of the octahedral iron oxide nanoparticle catalyst with a concave surface prepared by the preparation method according to any one of claims 1 to 7 as a catalyst for preparing a long-chain olefin reaction.