Catalyst of metal supported on phosphine ligand modified nitrogen-doped graphene oxide / porous carbon and preparation method and application thereof

Abstract

The application discloses a phosphine ligand modified nitrogen-doped graphene oxide / porous carbon supported metal catalyst and a preparation method and application thereof. The catalyst comprises phosphine ligand modified nitrogen-doped graphene oxide / porous carbon and rhodium supported on the nitrogen-doped graphene oxide / porous carbon; and the molar ratio of rhodium to phosphine is 1:1-100 in terms of elements. The phosphine ligand modified nitrogen-doped graphene oxide / porous carbon supported metal catalyst has better catalytic activity and product selectivity.

Description

Technical Field

[0001] This invention belongs to the field of hydroformylation technology, specifically relating to a nitrogen-doped graphene oxide / porous carbon-supported metal catalyst modified with phosphine ligands, its preparation method, and its application. Background Technology

[0002] Industrially, hydroformylation processes are mainly divided into homogeneous catalysis and two-phase catalysis. Homogeneous catalysis has advantages such as fast reaction rates and high activity, but the product and catalyst need to be separated by distillation. As the carbon chain length increases, the boiling point of the hydroformylation product, the higher carbon aldehyde, increases, requiring higher temperatures for product separation. However, highly active rhodium-based catalysts are easily deactivated at high temperatures; therefore, the high-temperature distillation used in homogeneous catalysis processes leads to the loss of precious metal catalysts, increasing production costs.

[0003] CN106622374A discloses a resin-based immobilized rhodium-phosphine complex catalyst, its preparation method, and its application. An organic polymer is used as a support, modified with phosphine ligands, and then a rhodium complex is bonded onto it to synthesize an immobilized rhodium-phosphine complex catalyst. The organic polymer is a phenolic resin, a phosphorus-containing phenolic resin, or a resorcinol resin. The organic polymer has a regular hexagonal mesoporous structure with a specific surface area of ​​220 m². 2 / g, pore volume 0.34cm 3 / g, with a pore size concentrated at 3.7nm. The preparation method of the resin-based immobilized rhodium phosphine complex catalyst includes the following steps:

[0004] 1) The organic polymer was added to a 10% (v / v) dilute nitric acid solution, refluxed at 100°C for 3 hours, washed with distilled water until the filtrate was neutral, and then vacuum dried at 50°C to obtain the activated carrier.

[0005] 2) Add 0.2 g of activated support to 20 mL of tetrahydrofuran, then add 3.3 mmol of triethylamine and 2.58 mmol of diphenylphosphine chloride. Reflux at room temperature for 24 h in N2 atmosphere. Wash the product with anhydrous ethanol, remove the solvent under vacuum, and then dry it under vacuum at 50 °C to obtain the modified support.

[0006] 3) Add 0.2 g of the modified carrier to 20 mL of toluene, then add 5.1 mg of rhodium acetylacetone dicarbonyl, reflux at room temperature for 24 h in N2 atmosphere, wash the obtained product with toluene, dry it under vacuum at 50 °C, and store it in N2 atmosphere.

[0007] Although this patent improves the activity of the catalyst, it still cannot simultaneously achieve high catalytic activity and product selectivity. Summary of the Invention

[0008] To address the aforementioned problems in the existing technology, this invention provides a novel catalyst for nitrogen-doped graphene oxide / porous carbon supported on metal and its preparation method, modified with phosphine ligands. This catalyst improves the reactivity and aldehyde selectivity of the hydroformylation reaction by modifying rhodium-loaded nitrogen-doped graphene oxide / porous carbon with phosphine ligands. Furthermore, as a heterogeneous catalyst, this catalyst exhibits excellent recovery performance after the hydroformylation reaction, and the separated and recovered catalyst composition can be recycled.

[0009] The first aspect of the present invention provides a catalyst for supporting metal on nitrogen-doped graphene oxide / porous carbon modified with phosphine ligands, the catalyst comprising nitrogen-doped graphene oxide / porous carbon modified with phosphine ligands, and rhodium supported on the nitrogen-doped graphene oxide / porous carbon; wherein, in terms of elements, the molar ratio of rhodium to phosphine is 1:1-100, preferably 1:24-60.

[0010] In this invention, "graphene oxide / porous carbon" refers to graphene oxide or porous carbon.

[0011] According to some embodiments of the catalyst of the present invention, the rhodium content, calculated as elemental rhodium, is 0.1-10% by weight, based on the weight of the catalyst. In the present invention, the rhodium loading content in the catalyst can be changed by adjusting the concentration of the rhodium leaching solution; however, it has been found through measurement that the catalyst of the present invention performs better when the rhodium content is in the range of 0.1-10% by weight.

[0012] According to some embodiments of the catalyst described in this invention, the nitrogen-doped graphene oxide / porous carbon-supported metal catalyst modified with phosphine ligands is used for olefin hydroformylation reactions, especially internal olefin hydroformylation reactions.

[0013] According to some embodiments of the catalyst described in this invention, the method for preparing the nitrogen-doped graphene oxide / porous carbon includes: mixing a dispersion of graphene oxide / porous carbon with a nitrogen-containing compound, stirring and then carrying out a hydrothermal reaction, followed by cooling, washing, filtering, and vacuum drying.

[0014] According to some embodiments of the catalyst described in this invention, the weight ratio of the graphene oxide / porous carbon dispersion to the nitrogen-containing compound is 1:10-300.

[0015] In some embodiments of the catalyst according to the present invention, the nitrogen-containing compound is urea.

[0016] According to some embodiments of the preparation method described in this invention, the content of graphene oxide / porous carbon is 1.0-6.0 mg relative to each mL of graphene oxide / porous carbon dispersion.

[0017] According to some embodiments of the catalyst described in this invention, the conditions for the hydrothermal reaction include: a temperature of 100-200°C and a time of 6-36 hours.

[0018] The second aspect of the present invention provides a method for preparing a nitrogen-doped graphene oxide / porous carbon supported metal catalyst modified with phosphine ligands, comprising: mixing nitrogen-doped graphene oxide / porous carbon with a solvent to obtain a mixture A; adding a rhodium-containing compound to the mixture A to obtain a mixture B; adding phosphine ligands to the mixture B and heating under nitrogen protection under reflux, cooling and filtering to obtain a solid, washing the solid and vacuum drying.

[0019] According to some embodiments of the preparation method of the present invention, the solvent is one or more of water, polar organic solvents, and non-polar organic solvents.

[0020] According to some embodiments of the preparation method described in this invention, the amount of solvent added is 400-600 mL relative to each g of nitrogen-doped graphene oxide / porous carbon.

[0021] According to some embodiments of the preparation method described in this invention, the content of the rhodium compound, calculated as rhodium, is 0.01-0.5 mg per mL of mixture B.

[0022] According to some embodiments of the preparation method of the present invention, the phosphine ligand is an organophosphine compound, more preferably one or more of triphenylphosphine, triphenyl phosphite, triphenylphosphine oxide, bidentate phosphine ligand, tridentate phosphine ligand, and polydentate phosphine ligand.

[0023] According to some embodiments of the preparation method described in this invention, the weight of the phosphine ligand is 1-60 mg relative to each mL of mixture B.

[0024] According to some embodiments of the preparation method described in this invention, the conditions for the heating reflux include: a temperature of 20-100°C and a time of 1-24 hours.

[0025] According to some embodiments of the preparation method of the present invention, the solvent used for cleaning is hot ethanol, preferably ethanol at a temperature of 40-50°C.

[0026] According to some embodiments of the preparation method of the present invention, the preparation method of the nitrogen-doped graphene oxide / porous carbon includes: mixing a dispersion of graphene oxide / porous carbon with a nitrogen-containing compound, stirring and then carrying out a hydrothermal reaction, followed by cooling, washing, filtering, and vacuum drying.

[0027] According to some embodiments of the preparation method described in this invention, the weight ratio of the graphene oxide / porous carbon dispersion to the nitrogen-containing compound is 1:10-300.

[0028] In some embodiments of the preparation method described in this invention, the nitrogen-containing compound is urea.

[0029] According to some embodiments of the preparation method described in this invention, the content of graphene oxide / porous carbon is 1.0-6.0 mg relative to each mL of graphene oxide / porous carbon dispersion.

[0030] According to some embodiments of the preparation method described in this invention, the conditions for the hydrothermal reaction include: a temperature of 100-200°C and a time of 6-36 hours.

[0031] According to some embodiments of the preparation method described in this invention, the vacuum drying temperature does not exceed 90°C.

[0032] According to some embodiments of the preparation method described in this invention, the rhodium-containing compound is as shown in formula (I):

[0033] Rh(L 1 ) x (L 2 ) y (L 3 ) z Formula (I)

[0034] Among them, L 1 Selected from carbonyl, halogen, acetylacetone, diphenylphosphine, cyclooctadiene, norbornene, and triphenylphosphine; L 2 and L 3 The same or different, each independently selected from hydrogen, carbonyl, chlorine, acetylacetone, diphenylphosphine, cyclooctadiene, norbornene and triphenylphosphine, x is an integer from 1 to 3, y and z are each independently selected from integers from 0 to 4, and x+y+z≤5.

[0035] According to some embodiments of the preparation method of the present invention, the rhodium-containing compound is selected from at least one of rhodium trichloride, rhodium acetylacetone dicarbonyl, rhodium chlorocarbonyl di(triphenylphosphine trisodium trisulfonate), rhodium chlorocarbonyl di(disulfonate triphenylphosphine disodium), rhodium chlorocarbonyl di(triphenylphosphine monosodium sulfonate), and rhodium chlorocarbonyl tri(triphenylphosphine trisodium trisulfonate).

[0036] According to some specific embodiments of the preparation method described in this invention, a method for preparing a nitrogen-doped graphene oxide / porous carbon supported metal catalyst modified with phosphine ligands includes, but is not limited to: mixing nitrogen-doped graphene oxide / porous carbon with a solvent to obtain a mixture A; adding a rhodium-containing compound to mixture A and stirring vigorously to obtain a mixture B; adding phosphine ligands to mixture B and heating, stirring and refluxing under nitrogen protection, cooling to room temperature and filtering to obtain a black solid; washing the black solid and vacuum drying overnight to obtain a rhodium-supported nitrogen-doped graphene oxide / porous carbon catalyst modified with phosphine ligands.

[0037] A third aspect of the present invention provides a catalyst for supporting metal on nitrogen-doped graphene oxide / porous carbon modified with phosphine ligands, prepared according to the above-described preparation method. The catalyst comprises nitrogen-doped graphene oxide / porous carbon modified with phosphine ligands, and rhodium supported on the nitrogen-doped graphene oxide / porous carbon; the molar ratio of rhodium to phosphine is 1:1-100, preferably 1:24-60, elementally.

[0038] According to some embodiments of the preparation method of the present invention, the rhodium content, calculated as rhodium element, is 0.1-10% by weight, based on the weight of the catalyst.

[0039] The fourth aspect of the present invention provides the application of the above-described catalyst modified with phosphine ligands, nitrogen-doped graphene oxide / porous carbon supported metal, or the above-described preparation method, in the hydroformylation of olefins, especially in the hydroformylation reaction of internal olefins.

[0040] The beneficial effects of this invention are:

[0041] The nitrogen-doped graphene oxide / porous carbon-supported metal catalyst modified with phosphine ligands of the present invention exhibits superior catalytic activity and product selectivity. It also demonstrates excellent recovery after the reaction, allowing the separated catalyst composition to be recycled, reducing production costs and facilitating industrial production applications. Detailed Implementation

[0042] To make the present invention easier to understand, the present invention will be described in detail below with reference to embodiments. These embodiments are for illustrative purposes only and are not limited to the scope of application of the present invention.

[0043]

Example 1

[0044] A graphene oxide dispersion with a concentration of 4 mg / mL (the graphene content is 4 mg per mL of dispersion) was prepared. Urea was added under vigorous stirring at a weight ratio of 1:100. After vigorous stirring at room temperature for 2 hours, the mixture was poured into a hydrothermal synthesis reactor and heated at 180°C for 12 hours. The mixture was then cooled to room temperature, washed, filtered, and vacuum dried overnight to obtain nitrogen-doped graphene oxide.

[0045] 0.6 g of nitrogen-doped graphene oxide was weighed and added to 300 mL of anhydrous ethanol. After vigorous sonication for 2 h, 0.032 g of RhCl3·3H2O was added, and the mixture was stirred for 30 min. 1 g of triphenylphosphine (TPP) was added under nitrogen protection, and the mixture was refluxed at 90 °C for 8 h. After cooling to room temperature, the mixture was filtered, washed with hot ethanol, and vacuum dried overnight to obtain a triphenylphosphine-modified rhodium-supported nitrogen-doped graphene oxide catalyst.

[0046] The rhodium content was determined by inductively coupled plasma mass spectrometry (ICP) based on the weight of the catalyst, and the rhodium content was 1.5% by weight (rhodium element).

[0047]

Example 2

[0048] A graphene oxide dispersion with a concentration of 4 mg / mL was prepared. Urea was added under vigorous stirring at a weight ratio of 1:100. After vigorous stirring at room temperature for 2 hours, the mixture was poured into a hydrothermal synthesis reactor and heated at 180°C for 12 hours. Then, it was cooled to room temperature, washed, filtered, and vacuum dried overnight to obtain nitrogen-doped graphene oxide.

[0049] 0.6 g of nitrogen-doped graphene oxide was weighed and added to 300 mL of dried toluene. After vigorous sonication for 2 h, 0.032 g of RhCl3·3H2O was added, and the mixture was stirred for 30 min. 1 g of triphenyl phosphite (TPPi) was added under nitrogen protection, and the mixture was refluxed at 90 °C for 8 h. After cooling to room temperature, the mixture was filtered, washed with hot ethanol, and vacuum dried overnight to obtain a triphenylphosphine-modified rhodium-supported nitrogen-doped graphene oxide catalyst.

[0050]

Example 3

[0051] The experimental method was the same as in Example 2, except that the weight ratio of graphene oxide dispersion to urea was changed to 1:50 when preparing nitrogen-doped graphene oxide, while the other experimental conditions remained unchanged.

[0052]

Example 4

[0053] The experimental method was the same as in Example 2, except that the weight ratio of graphene oxide dispersion to urea was changed to 1:10 when preparing nitrogen-doped graphene oxide, while the other experimental conditions remained unchanged.

[0054]

Example 5

[0055] The experimental method was the same as in Example 2, except that the weight ratio of graphene oxide dispersion to urea was changed to 1:200 when preparing nitrogen-doped graphene oxide, while the other experimental conditions remained unchanged.

[0056]

Example 6

[0057] The experimental method was the same as in Example 2, except that the weight ratio of graphene oxide dispersion to urea was changed to 1:300 when preparing nitrogen-doped graphene oxide, while the other experimental conditions remained unchanged.

[0058]

Example 7

[0059] The experimental method was the same as in Example 2, except that the amount of triphenyl phosphite added was changed to 0.8g, and the other experimental conditions remained unchanged.

[0060]

Example 8

[0061] The experimental method was the same as in Example 2, except that the amount of triphenyl phosphite added was changed to 0.6g, and the other experimental conditions remained unchanged.

[0062]

Example 9

[0063] The experimental method was the same as in Example 2, except that the amount of triphenyl phosphite added was changed to 0.3g, and the other experimental conditions remained unchanged.

[0064]

Example 10

[0065] The experimental method was the same as in Example 2, except that graphene oxide was replaced with porous carbon, nitrogen-doped porous carbon was used, and the other experimental conditions remained unchanged.

[0066]

Example 11

[0067] The experimental method was the same as in Example 2, except that the heating at 180°C for 12 hours was changed to heating at 120°C for 36 hours, while the other experimental conditions remained unchanged.

[0068]

Example 12

[0069] The experimental method was the same as in Example 1, except that the heating at 180°C for 12 hours was changed to heating at 250°C for 12 hours, while the other experimental conditions remained unchanged.

[0070] Comparative Example 1

[0071] The experimental method was the same as in Example 1, except that the graphene oxide was not doped with nitrogen, and the other experimental conditions remained unchanged.

[0072] Comparative Example 2

[0073] The experimental method was the same as in Example 2, except that no phosphine ligand modification was performed, and the other experimental conditions remained unchanged.

[0074] Comparative Example 3

[0075] The experimental method was the same as in Example 10, except that the porous carbon was not doped with nitrogen, and the other experimental conditions remained unchanged.

[0076] Comparative Example 4

[0077] The experimental method was the same as in Example 10, except that no phosphine ligand modification was performed, and the other experimental conditions remained unchanged.

[0078] [Test Example]

[0079] The catalysts of Examples 1-12 and Comparative Examples 1-4 were tested respectively, and their activity and selectivity were determined using a laboratory high-pressure reactor evaluation apparatus. The reactor had a volume of 50 mL and was placed in a heating mantle. The conditions for determining the catalyst activity and selectivity are shown in Table 1.

[0080] Table 1. Determination conditions for catalyst activity and selectivity

[0081] reaction temperature Reaction pressure Syngas composition reaction time Olefin feedstock solvent 100℃ 4MPa <![CDATA[H2:CO=1:1]]> 10h 2-Octenene Toluene

[0082] Catalyst activity and selectivity are characterized by olefin conversion and aldehyde selectivity, which are calculated using the following formulas:

[0083]

[0084]

[0085] In the catalyst, the molar ratio of Rh to P, expressed as an element, was determined by inductively coupled plasma mass spectrometry (ICP).

[0086] The test results are shown in Table 2.

[0087] Table 2. Effect of catalysts on the 2-octene hydroformylation reaction

[0088]

[0089]

[0090] As can be seen from Table 2, the nitrogen-doped graphene oxide / porous carbon supported metal catalyst modified with phosphine ligands of the present invention has better catalytic activity and product selectivity.

[0091] The above description is merely a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, based on the technical teachings provided by the present invention and as common knowledge in the field, other equivalent modifications and improvements can be made, and these should also be considered within the scope of protection of the present invention.

Claims

1. A catalyst for supporting metal on nitrogen-doped graphene oxide / porous carbon modified with phosphine ligands, the catalyst comprising nitrogen-doped graphene oxide / porous carbon modified with phosphine ligands, and rhodium supported on said nitrogen-doped graphene oxide / porous carbon; wherein the molar ratio of rhodium to phosphine is 1:35-60 based on elemental composition. The nitrogen-doped graphene oxide / porous carbon-supported metal catalyst modified with phosphine ligands is used for the hydroformylation reaction of internal olefins. The method for preparing the nitrogen-doped graphene oxide / porous carbon-supported metal catalyst modified with phosphine ligands includes: Nitrogen-doped graphene oxide / porous carbon and a solvent are mixed to obtain mixture A; A rhodium-containing compound was added to mixture A to obtain mixture B; After adding the phosphine ligand to mixture B, the mixture was heated under nitrogen protection and refluxed. After cooling, the solid was obtained by filtration, and the solid was washed and dried under vacuum. The method for preparing nitrogen-doped graphene oxide / porous carbon includes: mixing a dispersion of graphene oxide / porous carbon with urea, stirring and then carrying out a hydrothermal reaction, followed by cooling, washing, filtering, and vacuum drying. The weight ratio of the graphene oxide / porous carbon dispersion to urea is 1:100-300. The content of graphene oxide / porous carbon is 1.0-6.0 mg per mL of graphene oxide / porous carbon dispersion.

2. The catalyst according to claim 1, characterized in that, Based on the weight of the catalyst, the rhodium content is 0.1-10% by weight (rhodium element).

3. A method for preparing a nitrogen-doped graphene oxide / porous carbon-supported metal catalyst modified with phosphine ligands as described in claim 1 or 2, comprising: Nitrogen-doped graphene oxide / porous carbon and a solvent are mixed to obtain mixture A; A rhodium-containing compound was added to mixture A to obtain mixture B; Phosphine ligands were added to mixture B and heated under nitrogen protection and refluxed. After cooling, the mixture was filtered to obtain a solid, which was then washed and dried under vacuum.

4. The preparation method according to claim 3, characterized in that, The solvent is one or more of water, polar organic solvents, and non-polar organic solvents. The solvent addition is 400-600 mL per gram of nitrogen-doped graphene oxide / porous carbon; and / or, The content of rhodium compounds, calculated as rhodium, is 0.01-0.5 mg per mL of mixture B.

5. The preparation method according to claim 3, characterized in that, The phosphine ligand is an organophosphine compound; and / or, The weight of the phosphine ligand is 1-60 mg per mL of mixture B.

6. The preparation method according to claim 5, characterized in that, The organophosphine compound is selected from one or more of triphenylphosphine, triphenyl phosphite, triphenylphosphine oxide, and polydentate phosphine ligands.

7. The preparation method according to claim 5, characterized in that, The organophosphorus compound is selected from one or more bidentate phosphine ligands and tridentate phosphine ligands.

8. The preparation method according to any one of claims 3-7, characterized in that, The conditions for the heating reflux include: a temperature of 20-100℃ and a time of 1-24 hours; and / or, The solvent used for cleaning is ethanol at a temperature of 40-50℃.

9. The preparation method according to any one of claims 3-7, characterized in that, The conditions for the hydrothermal reaction include: a temperature of 100-200℃ and a time of 6-36h.

10. A catalyst of nitrogen-doped graphene oxide / porous carbon supported on metal modified with phosphine ligands prepared by the preparation method of any one of claims 3-9.

11. The use of the nitrogen-doped graphene oxide / porous carbon-supported metal catalyst modified with phosphine ligands according to any one of claims 1-2 and 10 in the hydroformylation of internal olefins.

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