Efficient cobalt catalytic system based on pyridyl-containing organic compound and application of efficient cobalt catalytic system in synthesis of methyl propionate through ethylene carbonylation

Abstract

The invention provides a method for preparing methyl propionate in one step by taking ethylene, carbon monoxide and methanol as raw materials. According to the method, cobalt salt or a cobalt compound and a pyridyl-containing organic compound form a catalytic system, and ethylene can be effectively catalyzed to be converted into methyl propionate at the temperature of 80-180 DEG C and the pressure of 0.5-8 Mpa. The mechanism for realizing the method is that divalent cobalt is promoted to be converted into key active species Co2 (CO) 8 and HCo (CO) 4 by utilizing the alkalinity and coordination capability of a pyridyl organic matter in a CO atmosphere with enough pressure, and a characteristic peak of a key intermediate HCo (CO) 4 is captured through electrospray ionization mass spectrometry (figure 4). Compared with the prior art, the methyl propionate synthesis method has the advantages that carbonyl esterification of ethylene can be realized under relatively mild conditions without using noble metals and acidic auxiliaries, unreacted gas can be recycled, the catalyst can be recycled through rectification, and the methyl propionate synthesis method is green and economical.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of homogeneous catalysis and carbonylation synthesis, and specifically discloses a homogeneous catalytic system for synthesizing methyl propionate (MP) from ethylene carbonylation. The core of the catalytic system is to use an active species formed by an organic compound containing a pyridyl group and a cobalt salt or cobalt compound as a catalyst. The system can efficiently catalyze the carbonylation reaction of ethylene, carbon monoxide and methanol (MeOH) under relatively mild conditions to generate MP in one step. Compared with the traditional ethylene carbonylation process, the method has the advantages of not using noble metals and acidic adjuvants, the ligand being cheap and easy to obtain, the catalytic system being separable and recyclable, and the reaction conditions being relatively mild, thereby providing a new way for the green and efficient synthesis of MP. BACKGROUND

[0002] Methyl propionate (MP) is an important organic ester compound. Due to its excellent physical and chemical properties, it has become a "multi-talented" chemical product in many key industries such as electronics, pharmaceuticals, daily chemicals, coatings and polymer materials. At present, the market demand for MP is very large and still growing. The optimization of the synthesis process of MP (especially the one-step carbonylation method of ethylene) and the innovation of the catalytic technology are not only related to the production cost of MP itself, but also directly affect the supply safety and sustainable development of its downstream industries such as methyl methacrylate (MMA), pharmaceutical synthesis intermediates, high-end electronic materials and optical materials.

[0003] At present, the traditional synthesis method of MP mainly relies on the esterification reaction of propionic acid and methanol. Considering the acquisition of propionic acid, this synthesis route is relatively complicated and generally involves the steps of synthesizing propionaldehyde from ethylene hydroformylation, preparing propionic acid from propionaldehyde oxidation, and esterifying propionic acid with methanol. Therefore, the industry pays more attention to the synthesis of MP from ethylene carbonylation ( Figure 9 ), which has high atom economy and rich raw material sources, and is currently the most ideal MP synthesis scheme. Therefore, developing a high-activity, high-selectivity and low-cost catalytic system for this reaction is a core challenge and technical high point for realizing the green and efficient production of MP, which has great significance for reducing the cost of downstream products and improving the competitiveness of the industry chain.

[0004] In the industrial practice of ethylene carbonylation, the most famous process for producing MP from ethylene is the alpha process developed by the British Lucite Company. This process uses palladium (Pd), phosphine-containing ligands and strong protonic acids as the core of the catalyst, and can catalyze the generation of MP from ethylene with high selectivity under mild conditions, which has attracted widespread attention in the industry. The use of noble metal Pd and the difficulty in synthesizing phosphine-containing ligands with high decomposition resistance seriously restricts the wide application of this process. In view of the increasing demand for MP at home and abroad, and from the perspective of MP supply safety and sustainable development, the academic and industrial circles in China are still exploring better methods for producing MP from ethylene.

[0005] In the existing literature and patent reports, patents CN115873221 A and CN116854921 A address the problems of high difficulty, high cost, and thermal instability of phosphorus-containing ligands in the alpha process of Lucite, UK. They propose modifying homogeneous phosphine ligands into functional heterogeneous phosphine polymers, which are then used to anchor Pd atoms for catalyzing the carbonylation of ethylene. Although this method solves the problem of easy deactivation and difficult recycling of homogeneous phosphine ligands in the recycling process, the heterogeneous process inevitably reduces reaction efficiency, and the polymerization of phosphine ligands itself requires methods such as Friedel-Crafts alkylation, increasing the cost of the entire process route. In addition, organic solvents such as benzene and acetonitrile are used, which still needs improvement in terms of green environmental protection.

[0006] Patents CN 101844981 A, CN 119191979 A, and CN 102531890 A address the problems of high corrosiveness of protonic acid and high separation and recovery costs in the alpha process. They propose replacing traditional inorganic or organic protonic acid with acidic ionic liquid. Acidic ionic liquid not only promotes the formation of key active species Pd-H bond with equal efficiency, but also has certain inhibitory effect on the polymerization of product MP due to its unique physicochemical properties. It is also easier to achieve subsequent separation and recovery. However, replacing traditional protonic acid with acidic ionic liquid does not solve the problem of using strong acid in the process with Pd as the core catalyst. Even though acidic ionic liquid is more mild than traditional acid, the synthesis of ionic liquid is relatively complex, and the purification steps are cumbersome. The viscosity and hygroscopicity of ionic liquid also limit its application to some extent.

[0007] Patents CN 114621089A, CN 108003024A, and CN 108003022A address the problems of high cost of Pd as a precious metal in the α process, its easy formation of zero-valent palladium upon contact with CO for deactivation, high Pd recovery costs, and insufficient utilization. They propose using acidic molecular sieves or metal oxides as supports to load ruthenium (Ru) for the catalytic carbonylation reaction of ethylene. Although this process achieves at least 80% MP yield, the heterogeneous reaction efficiency is low, the reaction temperature and time are relatively demanding, Ru is lost to some extent during the reaction, and Ru is still a precious metal, so the cost advantage compared to Pd is not significant. Patent CN114618521A reports a method for preparing methyl propionate using a supported bimetallic core-shell catalyst, but it requires the use of at least one precious metal, such as palladium, ruthenium, or rhodium, also resulting in a lack of significant cost advantage. Patent CN107497489A reports a process that uses non-precious metal Co as the main catalyst, organophosphorus compounds such as triphenylphosphine as ligands, and polyfluorinated compounds such as fluoroboric acid as structural aids, combined with organic acids such as benzenesulfonic acid and organic solvents, to catalyze the synthesis of MP from ethylene under relatively mild reaction conditions. Although this process avoids the use of precious metals, it involves a large number of various aids, resulting in high costs for subsequent purification and separation steps.

[0008] Therefore, developing novel green and recyclable catalysts with a single inexpensive transition metal as the core, and further simplifying the reaction system, is of great practical value in addressing the above problems. Summary of the Invention

[0009] To address the shortcomings of currently reported methods for synthesizing MP by carbonylation of ethylene with carbon monoxide, this invention provides a catalytic system consisting solely of inexpensive and readily available cobalt metal and pyridine-containing organic compounds. Compared to existing processes, the advantages of this invention are:

[0010] This catalytic system can catalyze the liquid-phase carbonylation reaction of ethylene, carbon monoxide and methanol to prepare MP under relatively mild conditions (80-180℃, 0.5-8 MPa) without the addition of precious metals, and no additional organic solvents or acidic auxiliaries are required. The catalyst can be separated and recovered by simple distillation after the reaction.

[0011] The mechanism by which this method is implemented is ( Figure 10 Under a sufficiently pressurized CO atmosphere, the basicity and coordination ability of pyridine organic compounds were utilized to promote the conversion of divalent cobalt into the key active species Co2(CO)8 and HCo(CO)4. The characteristic peak of the intermediate HCo(CO)4 was captured by electrospray mass spectrometry. Figure 11 ).

[0012] As a further implementable scheme of the method for preparing MP using ethylene, carbon monoxide and methanol as raw materials, the method comprises the following steps: sequentially adding a divalent cobalt salt or cobalt compound, an organic compound containing a pyridyl group (Ln), 10 mL of methanol into a 50 mL autoclave, respectively introducing ethylene and carbon monoxide to a specific pressure, and then performing a reaction after being heated to a specific temperature, and a methanol solution containing MP can be obtained after the reaction is completed.

[0013] As a further implementable scheme of the method for preparing MP using ethylene, carbon monoxide and methanol as raw materials, the catalytic system is composed of a divalent cobalt salt or cobalt compound and an organic compound containing a pyridyl group, wherein the metal cobalt is a main catalyst, and the organic compound containing a pyridyl ring is a ligand and an auxiliary agent.

[0014] As a further implementable scheme of the method for preparing MP using ethylene, carbon monoxide and methanol as raw materials, the divalent cobalt salt is one of cobalt acetate tetrahydrate, cobalt propionate, cobalt carbonate, cobalt hydroxide, cobalt iodide, cobalt tetrafluoroborate, and cobalt phosphate, and the cobalt compound is one of dicobalt octacarbonyl, tetracarbonylcobalt hydride, sodium tetracarbonylcobalt, and potassium tetracarbonylcobalt.

[0015] As a further implementable scheme of the method for preparing MP using ethylene, carbon monoxide and methanol as raw materials, the ligand and auxiliary agent used is an organic compound containing 1-3 pyridyl groups.

[0016] As a further implementable scheme of the method for preparing MP using ethylene, carbon monoxide and methanol as raw materials, the reaction temperature is 80-180°C.

[0017] As a further implementable scheme of the method for preparing MP using ethylene, carbon monoxide and methanol as raw materials, the reaction pressure is 0.5-8 MPa.

[0018] As a further implementable scheme of the method for preparing MP using ethylene, carbon monoxide and methanol as raw materials, the molar ratio of the metal cobalt to the organic compound containing a pyridyl group is 1:0.5-1:10.

[0019] As a further implementable scheme of the method for preparing MP using ethylene, carbon monoxide and methanol as raw materials, the molar ratio of the metal cobalt to ethylene is 1:20-1:80.

[0020] As a further implementable scheme of the method for preparing MP using ethylene, carbon monoxide and methanol as raw materials, the molar ratio of methanol to ethylene is 20:1-4:1. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 A gas chromatogram of the gas obtained after the reaction with 2,2'-dipyridyl (L7) as a ligand;

[0022] Figure 2 Gas chromatogram of the solution obtained after the reaction with 2,2'-bipyridine (L7) as ligand;

[0023] Figure 3 NMR of 3-hydroxypyridine ligand (L2) 1 H spectrum;

[0024] Figure 4 NMR of 3-hydroxypyridine ligand (L2) 13 C spectrum;

[0025] Figure 5 NMR of 5,5'-dimethoxy-2,2'-bipyridine ligand (L10) 1 H spectrum;

[0026] Figure 6 NMR of 5,5'-dimethoxy-2,2'-bipyridine ligand (L10) 13 C spectrum;

[0027] Figure 7 NMR of 1,10-phenanthroline-5,6-dione ligand (L15) 1 H spectrum;

[0028] Figure 8 NMR of 1,10-phenanthroline-5,6-dione ligand (L15) 13 C spectrum;

[0029] Figure 9 Reaction equation for the direct carbonylation of ethylene with CO to synthesize methyl propionate (MP);

[0030] Figure 10 Reaction equation for the direct carbonylation of ethylene with CO to synthesize methyl propionate (MP); n (n = 1-15) to synthesize MP;

[0031] Figure 11 Electrospray mass spectrum of the reactive intermediate HCo(CO)4. Specific embodiments

[0032] The embodiments of the present application will be described in detail below with reference to the examples, but those skilled in the art will understand that the following examples are only for illustration of the present application and should not be regarded as limiting the scope of the present application. Variations and implementations are included within the technical scope of the present application without departing from the spirit and scope of the present application.

[0033] Example 1:

[0034] Into a 50 mL autoclave, 250 mg of Co(OAc)2*4H2O, 95 mg of 2-hydroxypyridine (L1), 10 mL of methanol were added in sequence, then 2.5 Bar of ethylene and 60 Bar of carbon monoxide were introduced into the autoclave, and the reaction was carried out at 160°C for 20 h. After the reaction was completed, the autoclave was cooled to room temperature and the pressure was released, 0.12 g of methyl isobutyrate was added to the reaction solution as an internal standard, 1.0 mL of the sample was taken for gas chromatography analysis, and the yield of MP was calculated according to the internal standard factor. Under this condition, the yield of MP was 75.4%.

[0035]

[0036] Example 2:

[0037] Into a 50 mL autoclave, 250 mg of Co(OAc)2*4H2O, 95 mg of 2-hydroxypyridine (L1), 10 mL of methanol were added in sequence, then 2.5 Bar of ethylene and 60 Bar of carbon monoxide were introduced into the autoclave, and the reaction was carried out at 160°C for 20 h. After the reaction was completed, the autoclave was cooled to room temperature and the pressure was released, 0.12 g of methyl isobutyrate was added to the reaction solution as an internal standard, 1.0 mL of the sample was taken for gas chromatography analysis, and the yield of MP was calculated according to the internal standard factor. Under this condition, the yield of MP was 75.4%.

[0038]

[0039] Figure 3 NMR of the ligand corresponding to this example 1 H spectrum, Figure 4 NMR of the ligand corresponding to this example 13 C spectrum.

[0040] Example 3:

[0041] Into a 50 mL autoclave, 250 mg of Co(OAc)2*4H2O, 95 mg of 2-hydroxypyridine (L1), 10 mL of methanol were added in sequence, then 2.5 Bar of ethylene and 60 Bar of carbon monoxide were introduced into the autoclave, and the reaction was carried out at 160°C for 20 h. After the reaction was completed, the autoclave was cooled to room temperature and the pressure was released, 0.12 g of methyl isobutyrate was added to the reaction solution as an internal standard, 1.0 mL of the sample was taken for gas chromatography analysis, and the yield of MP was calculated according to the internal standard factor. Under this condition, the yield of MP was 75.4%.

[0042]

[0043] Example 4:

[0044] Example 1 : 250 mg of Co(OAc)2-4H2O, 167 mg of 2,6-dicarboxypyridine (L4), 10 mL of methanol were sequentially added to a 50 mL autoclave, and then 2.5 Bar of ethylene and 60 Bar of carbon monoxide were introduced into the autoclave, and the reaction was carried out at 160°C for 20 hours. After the reaction, the autoclave was cooled to room temperature and the pressure was released, 0.12 g of methyl isobutyrate was added to the reaction solution as an internal standard, 1.5 mL of the sample was subjected to gas chromatography analysis, and the yield of MP was calculated based on the internal standard factor. Under these conditions, the yield of MP was 62.7%.

[0045]

[0046] Example 5:

[0047] 250 mg of Co(OAc)2-4H2O, 145 mg of 8-hydroxyquinoline (L5), 10 mL of methanol were sequentially added to a 50 mL autoclave, and then 2.5 Bar of ethylene and 60 Bar of carbon monoxide were introduced into the autoclave, and the reaction was carried out at 160°C for 20 hours. After the reaction, the autoclave was cooled to room temperature and the pressure was released, 0.12 g of methyl isobutyrate was added to the reaction solution as an internal standard, 1.5 mL of the sample was subjected to gas chromatography analysis, and the yield of MP was calculated based on the internal standard factor. Under these conditions, the yield of MP was 72.4%.

[0048]

[0049] Example 6:

[0050] 250 mg of Co(OAc)2-4H2O, 145 mg of 8-methoxyquinoline (L6), 10 mL of methanol were sequentially added to a 50 mL autoclave, and then 2.5 Bar of ethylene and 60 Bar of carbon monoxide were introduced into the autoclave, and the reaction was carried out at 160°C for 20 hours. After the reaction, the autoclave was cooled to room temperature and the pressure was released, 0.12 g of methyl isobutyrate was added to the reaction solution as an internal standard, 1.5 mL of the sample was subjected to gas chromatography analysis, and the yield of MP was calculated based on the internal standard factor. Under these conditions, the yield of MP was 57.9%.

[0051]

[0052] Example 7:

[0053] Into a 50 mL autoclave, 250 mg of Co(OAc)2-4H2O, 156 mg of 2,2'-bipyridine (L7), and 10 mL of methanol were sequentially added, followed by introducing 2.5 Bar of ethylene and 60 Bar of carbon monoxide into the autoclave, and then the reaction was carried out at 160°C for 20 h. After the reaction was completed, the autoclave was cooled to room temperature and the pressure was released, 0.12 g of methyl isobutyrate was added to the reaction solution as an internal standard substance, 1.5 mL of the sample was taken for gas chromatography analysis, and the yield of MP was calculated according to the internal standard factor. Under this condition, the yield of MP was 79.8%.

[0054]

[0055] Figure 1 is a gas chromatogram of the gas after the reaction of this example, Figure 2 is a liquid gas chromatogram after the reaction of this example.

[0056] Figure 2 In the above formula, n is the molar amount of the substance to be calibrated, A is the gas chromatography peak area of the corresponding substance, m is the mass of the internal standard methyl isobutyrate, f 内 is the correction factor, and M is the relative molecular mass of the substance to be calibrated. n

[0057] In this example, the molar amounts of methyl propionate and 3-pentanone in the reaction solution are:

[0058] n(methyl propionate) = [(54.400 / 11.220) x 0.120 x 1.45] / 88.11 = 9.57 mmol

[0059] n(3-pentanone) = [(3.587 / 11.220) x 0.120 x 0.88] / 86.13 = 0.39 mmol

[0060] Example 8:

[0061] Into a 50 mL autoclave, 250 mg of Co(OAc)2-4H2O, 156 mg of 2,2'-bipyridine (L7), and 10 mL of methanol were sequentially added, followed by introducing 2.5 Bar of ethylene and 60 Bar of carbon monoxide into the autoclave, and then the reaction was carried out at 160°C for 20 h. After the reaction was completed, the autoclave was cooled to room temperature and the pressure was released, 0.12 g of methyl isobutyrate was added to the reaction solution as an internal standard substance, 1.5 mL of the sample was taken for gas chromatography analysis, and the yield of MP was calculated according to the internal standard factor. Under this condition, the yield of MP was 79.8%.

[0062]

[0063] ​Example 9:

[0064] Into a 50 mL autoclave, 250 mg of Co(OAc)2*4H2O, 15 mg of 2-phenylpyridine (L9), 10 mL of methanol were added in sequence, then 2.5 Bar of ethylene and 60 Bar of carbon monoxide were introduced into the autoclave, and the reaction was carried out at 160°C for 20 h. After the reaction was completed, the autoclave was cooled to room temperature and the pressure was released, 0.12 g of methyl isobutyrate was added to the reaction solution as an internal standard, 1.5 mL of sample was taken for gas chromatography analysis, and the yield of MP was calculated according to the internal standard factor. Under this condition, the yield of MP was 69.1%.

[0065]

[0066] Example 10:

[0067] Into a 50 mL autoclave, 250 mg of Co(OAc)2*4H2O, 216 mg of 5,5'-dimethoxy-2,2'-bipyridine (L10), 10 mL of methanol were added in sequence, then 2.5 Bar of ethylene and 60 Bar of carbon monoxide were introduced into the autoclave, and the reaction was carried out at 160°C for 20 h. After the reaction was completed, the autoclave was cooled to room temperature and the pressure was released, 0.12 g of methyl isobutyrate was added to the reaction solution as an internal standard, 1.5 mL of sample was taken for gas chromatography analysis, and the yield of MP was calculated according to the internal standard factor. Under this condition, the yield of MP was 80.9%.

[0068]

[0069] Figure 5 NMR of the ligand corresponding to this example 1 H spectrum, Figure 6 NMR of the ligand corresponding to this example 13 C spectrum.

[0070] Example 11:

[0071] Into a 50 mL autoclave, 250 mg of Co(OAc)2*4H2O, 244 mg of 5,5'-dicarboxy-2,2'-bipyridine (L11), 10 mL of methanol were added in sequence, then 2.5 Bar of ethylene and 60 Bar of carbon monoxide were introduced into the autoclave, and the reaction was carried out at 160°C for 20 h. After the reaction was completed, the autoclave was cooled to room temperature and the pressure was released, 0.12 g of methyl isobutyrate was added to the reaction solution as an internal standard, 1.5 mL of sample was taken for gas chromatography analysis, and the yield of MP was calculated according to the internal standard factor. Under this condition, the yield of MP was 42.8%.

[0072]

[0073] Example 12:

[0074] Into a 50 mL autoclave, 250 mg of Co(OAc)2-4H2O, 216 mg of 4,4'-dimethanol-2,2'-bipyridine (L12), 10 mL of methanol were added in sequence, then 2.5 Bar of ethylene and 60 Bar of carbon monoxide were introduced into the autoclave, and the reaction was carried out at 160°C for 20 h. After the reaction was completed, the autoclave was cooled to room temperature and the pressure was released, 0.12 g of methyl isobutyrate was added to the reaction solution as an internal standard, 1.5 mL of sample was taken for gas chromatography analysis, and the yield of MP was calculated according to the internal standard factor. Under this condition, the yield of MP was 82.7%.

[0075]

[0076] Example 13:

[0077] Into a 50 mL autoclave, 250 mg of Co(OAc)2-4H2O, 233 mg of α,α,α,-tripyridine (L13), 10 mL of methanol were added in sequence, then 2.5 Bar of ethylene and 60 Bar of carbon monoxide were introduced into the autoclave, and the reaction was carried out at 160°C for 20 h. After the reaction was completed, the autoclave was cooled to room temperature and the pressure was released, 0.12 g of methyl isobutyrate was added to the reaction solution as an internal standard, 1.5 mL of sample was taken for gas chromatography analysis, and the yield of MP was calculated according to the internal standard factor. Under this condition, the yield of MP was 75.1%.

[0078]

[0079] Example 14:

[0080] Into a 50 mL autoclave, 250 mg of Co(OAc)2-4H2O, 180 mg of 1,10-phenanthroline (L14), 10 mL of methanol were added in sequence, then 2.5 Bar of ethylene and 60 Bar of carbon monoxide were introduced into the autoclave, and the reaction was carried out at 160°C for 20 h. After the reaction was completed, the autoclave was cooled to room temperature and the pressure was released, 0.12 g of methyl isobutyrate was added to the reaction solution as an internal standard, 1.5 mL of sample was taken for gas chromatography analysis, and the yield of MP was calculated according to the internal standard factor. Under this condition, the yield of MP was 81.9%.

[0081]

[0082] Example 15:

[0083] Into a 50 mL autoclave, 250 mg of Co(OAc)2»4H2O, 214 mg of 1,10-phenanthroline-5,6-dione (L15), and 10 mL of methanol were sequentially added, followed by introduction of 2.5 Bar of ethylene and 60 Bar of carbon monoxide into the autoclave. The reaction was carried out at 160°C for 20 hours. After the reaction was completed, the autoclave was cooled to room temperature and the pressure was released. To the reaction solution, 0.12 g of methyl isobutyrate was added as an internal standard, 1.5 mL of the sample was subjected to gas chromatography analysis, and the yield of MP was calculated based on the internal standard factor. Under the above conditions, the yield of MP was 86.0%.

[0084]

[0085] Figure 7 NMR of the ligand corresponding to this example 1 H spectrum, Figure 8 NMR of the ligand corresponding to this example 13 C spectrum.

Claims

1. A method for preparing methyl propionate by one step from ethylene, carbon monoxide and methanol, which method comprises catalyzing liquid phase carbonylation reaction of ethylene, carbon monoxide and methanol to prepare methyl propionate with high selectivity at a temperature of 80-180℃ and a pressure of 0.5-8Mpa, using divalent cobalt salt or cobalt compound as main catalyst and organic compound containing pyridine group as ligand and adjuvant.

2. The method of claim 1, wherein The catalytic system is composed of metal cobalt and organic compound containing pyridine ring, wherein metal cobalt is main catalyst and organic compound containing pyridine ring is ligand and adjuvant.

3. The method of claim 2, wherein The divalent cobalt salt used is one of cobalt acetate tetrahydrate, cobalt propionate, cobalt carbonate, cobalt hydroxide, cobalt iodide, cobalt tetrafluoroborate and cobalt phosphate, and the cobalt compound is one of octacarbonyldicobalt, tetracarbonylcobalt hydride, sodium tetracarbonylcobalt and potassium tetracarbonylcobalt.

4. The method of claim 2, wherein The ligand and adjuvant used is organic compound containing 1-3 pyridine groups, and the organic compound containing 1 pyridine group has the following general structure: The organic compound containing 2 pyridine groups has the following general structure: wherein R 1 , R 2 , R 3 , R 4 , and R 5 are one of a hydrogen atom, a hydroxyl group, a carboxyl group, an alkoxy group, and an aryl group. The organic compound containing 3 pyridine groups is α, α, α, -terpyridine (L13).

5. The method of claim 2 wherein Methanol is used as reactant and solvent, and the amount of methanol is 10mL at a flux of 2.5Bar ethylene without adding any additional solvent.

6. The method of claim 1, wherein The reaction temperature is 80-180℃, and the characteristic is that the reaction pressure is 0.5-8Mpa.

7. The method of claim 1 wherein The molar ratio of metal cobalt to organic compound containing pyridine group is 1:0.5-1:

10.

8. The method of claim 1, wherein The molar ratio of metal cobalt to ethylene is 1:20-1:

80.

9. The method of claim 1 wherein The molar ratio of methanol to ethylene is 20:1-4:1.

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