A nano cobalt catalyst, a preparation method and application thereof in olefin hydroesterification reaction

Abstract

The application provides a nano cobalt catalyst, a preparation method and application thereof in olefin hydroesterification, and belongs to the technical field of catalysts.The nano cobalt catalyst comprises active metal cobalt and nitrogen-doped nano carbon material, and forms cobalt-nitrogen active sites through coordination; and the active metal cobalt is uniformly dispersed on the surface of the nitrogen-doped nano carbon material.The application takes melamine and cyanuric acid as carbon source and nitrogen source at the same time, adjusts the type, quantity and polymerization condition of aldehyde / alcohol, and thus the nano cobalt catalyst is prepared.The nano cobalt catalyst prepared by the application has controllable structure, and the catalytic activity and catalytic stability are significantly improved.The catalyst has excellent catalytic performance, is easy to separate and recycle in the olefin hydroesterification.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalysts, in particular to a nano cobalt catalyst, a preparation method and application thereof in olefin hydroesterification reaction. BACKGROUND

[0002] Fatty and aromatic carboxylic acid esters, including isononyl acid ester, heptanoic acid ester, phenylpropionic acid ester, etc., have wide applications in the fields of cosmetics, medicine, plasticizers, etc. For example, the hydrolysis product isononyl acid and the hydrogenation product isononyl alcohol of isononyl acid ester can be used as raw materials for synthesizing high-grade lubricating oil, medical intermediates and metal processing fluid, and can also be used for modifying alkyd resin to significantly improve the oxidation resistance and impact resistance of the resin material.

[0003] Olefin hydroesterification reaction is one of the important methods for producing carboxylic acid esters. At present, many types of homogeneous catalytic reaction systems have been developed and applied. Literature [Fine Chemicals, 2001, 18, 109] reports that when Co2(CO)8 - When pyridine is used as a catalyst, diisobutene can be efficiently carbonylated to synthesize isononyl acid ester in one step under optimized conditions.

[0004] Patent CN 201810616930.8 discloses a catalytic system composed of Co and / or Rh as active metal and nitrogen-containing heterocyclic ligand, which is suitable for preparing isononyl acid ester by diisobutene hydroformylation, and exhibits very excellent catalytic performance. Although the homogeneous catalytic system has high reaction activity and good performance, it has problems such as poor stability, cannot be reused, and difficult product separation during the reaction process, which limits the industrial application of the homogeneous catalytic process.

[0005] In recent years, the research on heterogeneous catalysts for diisobutene hydroformylation and hydroesterification has attracted widespread attention.

[0006] For example, patent CN 201911220649.3 discloses a method for diisobutene hydroformylation to generate isononyl aldehyde and isononyl alcohol, and the reaction product can be oxidized and esterified to prepare isononyl acid ester. In this process, a polymer catalyst is used, and the active components Rh and Co are dispersed in the solid organic ligand polymer in the form of coordination. The weak interaction between metal ions and ligand polymer causes poor stability of the catalyst. CN202210919867.1 discloses a cobalt-based catalyst dispersed by vinylpyridine or imidazole polymer, but in the diisobutene hydroesterification reaction, the catalyst also has problems such as poor stability and difficult reuse.

[0007] Therefore, developing more efficient and stable solid catalytic systems will help promote the industrial application of olefin hydroesterification process. SUMMARY

[0008] In view of the above, the purpose of the present application is to provide a high-efficiency stable nano-cobalt catalyst and a preparation method thereof, which exhibits excellent catalytic performance in olefin hydroesterification reaction.

[0009] In order to achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0010] A nano-cobalt catalyst, comprising active metal cobalt and nitrogen-doped nanocarbon material, and forming cobalt-nitrogen active sites through coordination; the active metal cobalt is uniformly dispersed on the surface of the nitrogen-doped nanocarbon material.

[0011] The content of the active metal cobalt is 5-20wt%, and the balance is the nitrogen-doped nanocarbon material.

[0012] Another purpose of the present application is to provide a preparation method of the nano-cobalt catalyst, comprising the following steps:

[0013] (1) mixing cobalt salt, melamine and cyanuric acid in water to form a uniformly dispersed solution;

[0014] (2) under vigorous stirring, adding an aldehyde-alcohol mixed solution to the solution of step (1);

[0015] (3) after the addition is completed, heating to 40-100℃ and keeping for 10-40 hours, then evaporating the solvent to obtain a solid;

[0016] (4) drying the solid obtained in step (3) at 110℃ for 12 hours, and then calcining at 500-1000℃ for 2-10 hours in a protective gas stream to obtain the nano-cobalt catalyst.

[0017] Preferably, the cobalt salt in step (1) is at least one of cobalt nitrate, cobalt acetate, dicobalt octacarbonyl, cobalt chloride and cobalt sulfate.

[0018] Preferably, the molar ratio of the cobalt salt, melamine and cyanuric acid in step (1) is 1-5:10:10.

[0019] Preferably, the aldehyde in the aldehyde-alcohol mixed solution in step (2) is at least one of formaldehyde, acetaldehyde and benzaldehyde; and the alcohol is at least one of methanol, benzyl alcohol, ethylene glycol, glycerol, pentaerythritol, xylitol and sorbitol.

[0020] Preferably, the molar ratio of the aldehyde and the alcohol in step (2) is 0.5-5:0.1-2.

[0021] Preferably, the protective gas in step (4) is at least one of nitrogen, argon, hydrogen and carbon dioxide.

[0022] The application further provides the application of the nano cobalt catalyst, in particular, the application of the nano cobalt catalyst in the hydroesterification reaction of olefin, carbon monoxide and monohydric alcohol to generate carboxylic acid ester, in the reaction process, the filling amount of carbon monoxide is 6 MPa, the temperature is rapidly increased to 150 DEG C, and the reaction is performed for 20 hours.

[0023] Preferably, the olefin includes at least one of diisobutene, n-hexene, styrene and cyclohexene; and the monohydric alcohol includes at least one of methanol, ethanol, isopropyl alcohol and tert-butyl alcohol.

[0024] Preferably, the molar ratio of the olefin to the monohydric alcohol is 1:20; and the ratio of the catalyst to the olefin is 10-12 g:1 mol.

[0025] Compared with the prior art, the application has the following beneficial effects:

[0026] (1) The nano cobalt catalyst is synthesized by taking melamine and cyanuric acid as the carbon source and nitrogen source, adjusting the type, amount and polymerization condition of aldehyde / alcohol, and effectively controlling the polymerization process, polymer composition structure and catalyst performance, so that the high-efficiency stable catalyst is synthesized.

[0027] (2) The nano cobalt catalyst is prepared by using industrial bulk chemicals as raw materials, and has the advantages of simple preparation process, low cost and easy realization of scale-up production.

[0028] (3) The nano cobalt catalyst has excellent catalytic performance in the olefin hydroesterification reaction, is easy to separate and recycle, has simple reaction process and is suitable for industrial application. DETAILED DESCRIPTION

[0029] The application will be further described below in combination with examples.

[0030] Example 1

[0031] A preparation method of a nano cobalt catalyst, the steps are as follows:

[0032] (1) 10 g of Co(NO3)2·6H2O, 20 g of melamine and 20.5 g of cyanuric acid are added into 350 mL of deionized water to form a uniformly dispersed solution;

[0033] (2) 25.7 g of a formaldehyde solution with a concentration of 37 wt% and 5.1 g of methanol are mixed to obtain an aldehyde-alcohol mixed solution, deionized water is added to the aldehyde-alcohol mixed solution to make the volume 100 mL, and the solution is added dropwise into the solution obtained in step (1) at a speed of 2 mL / min under vigorous stirring;

[0034] (3) after the dropwise addition is completed, the temperature is increased to 80 DEG C and maintained for 24 hours, and then the solvent is evaporated to obtain a solid;

[0035] (4) The solid obtained in step (3) was dried at 110°C for 12 hours, and then calcined at 800°C for 4 hours under a nitrogen flow of 40 mL / min, to obtain a nano-cobalt catalyst A with a cobalt content of 10 wt%.

[0036] The nano-cobalt catalyst A was used in the hydroesterification of olefins, and the steps were as follows:

[0037] 10 g of diisobutene, 57.1 g of methanol and 0.9 g of catalyst A were put into a 200 mL stainless steel batch reactor, which was then sealed. After three times of replacement with 2 MPa nitrogen, 6 MPa carbon monoxide was filled, and the temperature was quickly raised to 150°C and maintained for 20 hours. After the reaction was completed, the temperature was lowered in an ice bath, and a small amount of liquid was taken for quantitative analysis. Qualitative and quantitative analysis was performed by gas chromatography. The sample was tested by an Aglient 7890A gas chromatograph equipped with an FID detector and an HP-5 capillary column. The injector temperature was 260°C, and the detector temperature was 280°C. The conversion rate and selectivity were calculated by an internal standard method.

[0038] Example 2

[0039] A method for preparing a nano-cobalt catalyst, and the steps were as follows:

[0040] (1) 4.3 g of Co(OAc)2·4H2O, 20 g of melamine and 20.5 g of cyanuric acid were added to 175 mL of deionized water to form a uniformly dispersed solution;

[0041] (2) 25.7 g of a formaldehyde solution with a concentration of 37 wt% and 5.1 g of methanol were mixed to obtain an aldehyde-alcohol mixed solution. Deionized water was added to the aldehyde-alcohol mixed solution to make up to 100 mL. Under vigorous stirring, the solution was added dropwise to the solution obtained in step (1) at a rate of 2 mL / min;

[0042] (3) After the dropwise addition was completed, the temperature was raised to 80°C and maintained for 24 hours, and then the solvent was evaporated;

[0043] (4) The solid obtained in step (3) was dried at 110°C for 12 hours, and then calcined at 800°C for 4 hours under a nitrogen flow of 40 mL / min, to obtain a nano-cobalt catalyst B with a cobalt content of 5 wt%.

[0044] The application method of the catalyst B and the product analysis were the same as in Example 1.

[0045] Example 3

[0046] A method for preparing a nano-cobalt catalyst, and the steps were as follows:

[0047] (1) 11.7 g of Co2(CO)8, 20 g of melamine and 20.5 g of cyanuric acid were added into 175 mL of deionized water to form a uniformly dispersed solution;

[0048] (2) 25.7 g of formaldehyde solution with a concentration of 37 wt% and 5.1 g of methanol were mixed to obtain an aldehyde-alcohol mixed solution, deionized water was added to the aldehyde-alcohol mixed solution to make up to 100 mL, and under vigorous stirring, it was added dropwise into the solution obtained in step (1) at a speed of 2 mL / min;

[0049] (3) After the dropwise addition was completed, the temperature was raised to 80°C and maintained for 24 hours, and then the solvent was evaporated;

[0050] (4) After the solid obtained in step (3) was dried at 110°C for 12 hours, it was calcined at 800°C for 4 hours under a nitrogen gas flow of 40 mL / min, to obtain a nano-cobalt catalyst C with a cobalt content of about 20 wt%.

[0051] The application method of the catalyst C and the product analysis are the same as in Example 1.

[0052] Example 4

[0053] A method for preparing a nano-cobalt catalyst, the steps being as follows:

[0054] (1) 8.2 g of CoCl2·6H2O, 20 g of melamine and 20.5 g of cyanuric acid were added into 175 mL of deionized water to form a uniformly dispersed solution;

[0055] (2) 6.5 g of formaldehyde solution with a concentration of 37 wt% and 0.5 g of methanol were mixed to obtain an aldehyde-alcohol mixed solution, deionized water was added to the aldehyde-alcohol mixed solution to make up to 100 mL, and under vigorous stirring, it was added dropwise into the solution obtained in step (1) at a speed of 2 mL / min;

[0056] (3) After the dropwise addition was completed, the temperature was raised to 80°C and maintained for 24 hours, and then the solvent was evaporated;

[0057] (4) After the solid obtained in step (3) was dried at 110°C for 12 hours, it was calcined at 800°C for 4 hours under a nitrogen gas flow of 40 mL / min, to obtain a nano-cobalt catalyst D with a cobalt content of about 10 wt%.

[0058] The application method of the catalyst D and the product analysis are the same as in Example 1.

[0059] Example 5

[0060] A method for preparing a nano-cobalt catalyst, the steps being as follows:

[0061] (1) 9.7 g of CoSO4.7H2O, 20 g of melamine and 20.5 g of cyanuric acid were added into 175 mL of deionized water to form a uniformly dispersed solution;

[0062] (2) 64.3 g of formaldehyde solution with a concentration of 37 wt% and 10.2 g of methanol were mixed to obtain an aldehyde-alcohol mixed solution, deionized water was added to the aldehyde-alcohol mixed solution to make up to 100 mL, and under vigorous stirring, it was added dropwise into the solution obtained in step (1) at a speed of 2 mL / min;

[0063] (3) After the dropwise addition was completed, the temperature was raised to 80°C and maintained for 24 hours, and then the solvent was evaporated;

[0064] (4) After the solid obtained in step (3) was dried at 110°C for 12 hours, it was calcined at 800°C for 4 hours under a nitrogen gas flow of 40 mL / min, to obtain a nano-cobalt catalyst E with a cobalt content of about 10 wt%.

[0065] The application method of the catalyst E and the product analysis are the same as in Example 1.

[0066] Example 6

[0067] A method for preparing a nano-cobalt catalyst, the steps are as follows:

[0068] (1) 10 g of Co(NO3)2.6H2O, 20 g of melamine and 20.5 g of cyanuric acid were added into 350 mL of deionized water to form a uniformly dispersed solution;

[0069] (2) 34.9 g of acetaldehyde solution with a concentration of 40 wt% and 17.1 g of benzyl alcohol were mixed to obtain an aldehyde-alcohol mixed solution, deionized water was added to the aldehyde-alcohol mixed solution to make up to 100 mL, and under vigorous stirring, it was added dropwise into the solution obtained in step (1) at a speed of 2 mL / min;

[0070] (3) After the dropwise addition was completed, the temperature was raised to 40°C and maintained for 40 hours, and then the solvent was evaporated;

[0071] (4) After the solid obtained in step (3) was dried at 110°C for 12 hours, it was calcined at 800°C for 4 hours under a nitrogen gas flow of 40 mL / min, to obtain a nano-cobalt catalyst F with a cobalt content of about 10 wt%.

[0072] The application method of the catalyst F and the product analysis are the same as in Example 1.

[0073] Example 7

[0074] A method for preparing a nano-cobalt catalyst, the steps are as follows:

[0075] (1) 10 g Co(N03)2-6H20, 20 g melamine and 20.5 g cyanuric acid were added into 350 mL deionized water to form a uniformly dispersed solution;

[0076] (2) 33.6 g benzaldehyde and 9.8 g ethylene glycol were mixed to obtain an aldehyde-alcohol mixed solution, deionized water was added to the aldehyde-alcohol mixed solution to make up to 100 mL, and under vigorous stirring, it was added dropwise into the solution obtained in step (1) at a speed of 2 mL / min;

[0077] (3) After the dropwise addition was completed, the temperature was raised to 100°C and maintained for 10 hours, and then the solvent was evaporated;

[0078] (4) After the solid obtained in step (3) was dried at 110°C for 12 hours, it was calcined at 800°C for 4 hours under a nitrogen gas flow of 40 mL / min, to obtain a nano-cobalt catalyst G with a cobalt content of about 10 wt%.

[0079] The application method of the catalyst G and the product analysis are the same as in Example 1.

[0080] Example 8

[0081] A method for preparing a nano-cobalt catalyst, the steps being as follows:

[0082] (1) 10 g Co(N03)2-6H20, 20 g melamine and 20.5 g cyanuric acid were added into 350 mL deionized water to form a uniformly dispersed solution;

[0083] (2) 25.7 g formaldehyde solution with a concentration of 37 wt% and 14.6 g glycerol were mixed to obtain an aldehyde-alcohol mixed solution, deionized water was added to the aldehyde-alcohol mixed solution to make up to 100 mL, and under vigorous stirring, it was added dropwise into the solution obtained in step (1) at a speed of 2 mL / min;

[0084] (3) After the dropwise addition was completed, the temperature was raised to 80°C and maintained for 24 hours, and then the solvent was evaporated;

[0085] (4) After the solid obtained in step (3) was dried at 110°C for 12 hours, it was calcined at 1000°C for 2 hours under an argon gas flow of 40 mL / min, to obtain a nano-cobalt catalyst H with a cobalt content of about 10 wt%.

[0086] The application method of the catalyst H and the product analysis are the same as in Example 1.

[0087] Example 9

[0088] A method for preparing a nano-cobalt catalyst, the steps being as follows:

[0089] (1) 10 g Co(N03)2-6H20, 20 g melamine and 20.5 g cyanuric acid were added into 350 mL deionized water to form a uniformly dispersed solution;

[0090] (2) 25.7 g formaldehyde solution with a concentration of 37 wt% and 21.6 g pentaerythritol were mixed to obtain an aldehyde-alcohol mixed solution, deionized water was added to the aldehyde-alcohol mixed solution to make the volume 100 mL, and then the solution was added dropwise into the solution obtained in step (1) at a speed of 2 mL / min under vigorous stirring;

[0091] (3) After the dropwise addition was completed, the temperature was raised to 80°C and maintained for 24 hours, and then the solvent was evaporated;

[0092] (4) The solid obtained in step (3) was dried at 110°C for 12 hours, and then calcined at 500°C for 10 hours in a hydrogen gas flow of 40 mL / min to obtain a nano-cobalt catalyst J with a cobalt content of about 10 wt%.

[0093] The application method of the catalyst J and the product analysis are the same as those of Example 1.

[0094] Example 10

[0095] A preparation method of a nano-cobalt catalyst, the steps being as follows:

[0096] (1) 10 g Co(N03)2-6H20, 20 g melamine and 20.5 g cyanuric acid were added into 350 mL deionized water to form a uniformly dispersed solution;

[0097] (2) 25.7 g formaldehyde solution with a concentration of 37 wt% and 24.1 g xylitol were mixed to obtain an aldehyde-alcohol mixed solution, deionized water was added to the aldehyde-alcohol mixed solution to make the volume 100 mL, and then the solution was added dropwise into the solution obtained in step (1) at a speed of 2 mL / min under vigorous stirring;

[0098] (3) After the dropwise addition was completed, the temperature was raised to 80°C and maintained for 24 hours, and then the solvent was evaporated;

[0099] (4) The solid obtained in step (3) was dried at 110°C for 12 hours, and then calcined at 800°C for 4 hours in a carbon dioxide gas flow of 40 mL / min to obtain a nano-cobalt catalyst K with a cobalt content of about 10 wt%.

[0100] The application method of the catalyst K and the product analysis are the same as those of Example 1.

[0101] Example 11

[0102] A preparation method of a nano-cobalt catalyst, the steps being as in Example 1.

[0103] In the catalyst evaluation process, 7.5 g of n-hexene and 82.1 g of ethanol were used to replace diisobutylene and methanol, respectively. Other processes and product analyses were the same as in Example 1.

[0104] Example 12

[0105] A method for preparing a nano-cobalt catalyst, the steps of which are as described in Example 1.

[0106] In the catalyst evaluation process, 9.3 g of styrene and 107.1 g of isopropanol were used to replace diisobutylene and methanol, respectively. Other processes and product analyses were the same as in Example 1.

[0107] Example 13

[0108] A method for preparing a nano-cobalt catalyst, the steps of which are as described in Example 1.

[0109] In the catalyst evaluation process, 7.3 g of cyclohexene and 131.7 g of tert-butanol were used to replace diisobutylene and methanol, respectively. Other processes and product analyses were the same as in Example 1.

[0110] Comparative Example 1

[0111] Comparative Example 1 uses 0.9 g Co2(CO)8 and 0.9 g pyridine instead of the nano-cobalt catalyst.

[0112] Other process and product analyses are the same as in Example 1.

[0113] The analytical results of the products of Examples 1-13 and Comparative Example 1 are shown in Table 1:

[0114] Table 1

[0115] Catalyst Olefin conversion (%) Carboxylate selectivity (%) Example 1 A 95.2 86.8 Example 2 B 70.8 82.5 Example 3 C >99 74.1 Example 4 D 60.6 76.5 Example 5 E 68.4 70.1 Example 6 F 83.5 66.7 Example 7 G 84.0 78.4 Example 8 H 80.2 81.5 Example 9 I 77.8 84.0 Example 10 J 70.4 63.8 Example 11 A 95.6 89.4 Example 12 A 80.1 86.6 Example 13 A 68.7 74.1 Comparative Example 1 Co2(CO)8 + pyridine 88.4 82.1

[0116] Cyclic performance test of catalyst A:

[0117] After the reaction, catalyst A was filtered and washed with methanol, then dried in a vacuum drying oven at 50°C for 10 hours. Other operations and product analysis were the same as in Example 1. The test results are shown in Table 2.

[0118] Table 2

[0119] Cycle number Diisobutylene conversion / % Methyl isononanoate selectivity / % 0 95.2 86.8 1 95.3 86.3 2 94.8 85.6 3 94.9 85.5 4 95.2 86.3 5 95.3 85.8

[0120] As shown in Tables 1 and 2, the nano-cobalt catalyst prepared by the present invention can efficiently prepare carboxylic acid esters by olefin hydrogen esterification reaction. The catalyst has excellent reactivity and target product selectivity, good stability, and is easy to separate and reuse, making it suitable for large-scale industrial production. It has high economic value and broad industrial application prospects. Catalyst A can still maintain high catalytic activity and product selectivity after 5 cycles, indicating that catalyst A has good reusability.

[0121] The above merely describes the preferred embodiments of the present application, and it should be pointed out that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered as falling within the protection scope of the present application.

Claims

1. Use of a nanocobalt catalyst, characterized in that, The nano cobalt catalyst is used for hydroesterification reaction of olefin, carbon monoxide and monohydric alcohol to generate carboxylic acid ester, in which the carbon monoxide is filled at 6 MPa, and the temperature is rapidly increased to 150 DEG C, and the reaction is carried out for 20 hours; The nano cobalt catalyst comprises active metal cobalt and nitrogen-doped nanocarbon material, and the cobalt-nitrogen active site is formed through coordination. The content of the active metal cobalt is 5-20 wt%, and the balance is the nitrogen-doped nanocarbon material. The preparation method of the nano cobalt catalyst comprises the following steps: (1) mixing cobalt salt, melamine and cyanuric acid in water to form a uniformly dispersed solution; (2) adding dropwise an aldehyde-alcohol mixed solution to the solution in step (1) under vigorous stirring; (3) after the dropwise addition is completed, the temperature is increased to 40-100 DEG C and kept for 10-40 hours, and then the solvent is evaporated to obtain a solid; (4) the solid obtained in step (3) is dried at 110 DEG C for 12 hours, and then calcined at 500-1000 DEG C for 2-10 hours in a protective gas stream to obtain the nano cobalt catalyst.

2. Use of the nanocobalt catalyst according to claim 1, characterized in that, The cobalt salt in step (1) is at least one of cobalt nitrate, cobalt acetate, dicobalt octacarbonyl, cobalt chloride and cobalt sulfate.

3. Use of the nanocobalt catalyst according to claim 1, characterized in that, The molar ratio of the cobalt salt, melamine and cyanuric acid in step (1) is 1-5:10:

10.

4. Use of the nanocobalt catalyst according to claim 1, characterized in that, The aldehyde in the aldehyde-alcohol mixed solution in step (2) is at least one of formaldehyde, acetaldehyde and benzaldehyde; and the alcohol is at least one of methanol, benzyl alcohol, ethylene glycol, glycerol, pentaerythritol, xylitol and sorbitol.

5. Use of the nanocobalt catalyst according to claim 1, characterized in that, The molar ratio of the aldehyde and alcohol in step (2) is 0.5-5:0.1-2.

6. Use of the nanocobalt catalyst according to claim 1, characterized in that, The protective gas in step (4) is at least one of nitrogen, argon, hydrogen and carbon dioxide.

7. Use of the nanocobalt catalyst according to claim 1, characterized in that, The olefin comprises at least one of diisobutene, n-hexene, styrene and cyclohexene; and the monohydric alcohol comprises at least one of methanol, ethanol, isopropyl alcohol and tert-butyl alcohol.

8. Use of the nanocobalt catalyst according to claim 1, characterized in that, The molar ratio of the olefin to the monohydric alcohol is 1:20; and the ratio of the catalyst to the olefin is 10-12 g:1 mol.