Synthesis method and application of carbonyl cobalt ionic liquid

Abstract

The invention discloses a synthesis method of carbonyl cobalt ionic liquid and application of the carbonyl cobalt ionic liquid in synthesis of beta-hydracrylate. The cobalt carbonyl ionic liquid is synthesized from the cobalt octacarbonyl, the ionic liquid and the ligand through a one-pot method, an intermediate product purification step is not needed, the process is simple, and the problems that a traditional preparation method of the cobalt carbonyl ionic liquid is low in conversion rate and complex in process are solved. The carbonyl cobalt ionic liquid can be used as a catalyst to be applied to a reaction for synthesizing beta-hydracrylate from ethylene oxide, and the catalyst has the advantages of good catalytic activity, high selectivity, easiness in product separation and circulation and the like.

Description

Technical Field

[0001] The present invention belongs to the field of fine chemicals, and in particular relates to a synthesis method of a cobalt carbonyl ionic liquid and its application. Background Art

[0002] 1,3-Propanediol (1,3-PDO) is an important fine chemical used as a raw material in the production of antifreeze, plasticizers, preservatives, and emulsifiers. It is also widely used in the food, coatings, cosmetics, and pharmaceutical industries, generating significant market demand. 1,3-PDO is a key monomer in the synthesis of polyurethanes. It can be polyesterified with terephthalic acid to produce poly(trimethylene terephthalate) (PTT), a novel polyester fiber material. This polyester material exhibits advantages such as light resistance, low water absorption, excellent stability, good resilience, biodegradability, and minimal environmental impact, offering broad application prospects.

[0003] β-Hydroxypropionate is a key intermediate in the synthesis of 1,3-PDO. It is currently mainly prepared by ethylene oxide hydroesterification. Its synthesis reaction is shown as follows: .

[0004] The development of new catalysts is a key research focus for the hydroesterification of epoxides. Among them, carbonyl cobalt ionic liquids have attracted the attention of researchers both domestically and internationally due to their high activity, stability, and ease of recovery and reuse.

[0005] Patent CN 106995391 A discloses a method for preparing a 1,1,3,3-tetraalkylguanidine carbonyl cobalt metal organic ionic liquid catalyst. The patent first uses Co2(CO)8 as a raw material to obtain an organic solution of tetracarbonyl cobalt potassium, and then obtains the tetraalkylguanidine carbonyl cobalt metal organic ionic liquid catalyst by a double decomposition reaction with tetraalkylguanidine hydrochloride.

[0006] Patent CN 101973881B discloses a method for preparing 1-R-3-methylimidazolium tetracarbonyl cobalt ionic liquid catalyst. This patent uses a divalent cobalt salt as a raw material and potassium borohydride as a reducing agent. The obtained potassium tetracarbonyl cobalt solution is ion-exchanged with imidazole hydrochloride to obtain the imidazole tetracarbonyl cobalt ionic liquid catalyst.

[0007] In summary, the synthesis of cobalt carbonyl ionic liquid catalysts typically requires the synthesis of potassium or sodium cobalt carbonyl, followed by an ion exchange reaction with the corresponding ionic liquid. The complex synthesis process, coupled with the air-sensitivity and inconvenient storage of the reaction intermediates, limits their large-scale industrial application. The addition of basic ligands, such as nitrogen-containing heterocyclic compounds, can improve the conversion rate of epoxide hydroesterification reactions. Epoxide hydroesterification systems catalyzed by cobalt carbonyl ionic liquids typically require the addition of a promoter. Summary of the Invention

[0008] To address these issues, the present invention develops a one-pot method for preparing cobalt carbonyl ionic liquids. This method eliminates the need for intermediate product purification, resulting in a simple process and avoiding the low conversion rates and complex processes associated with conventional methods for preparing cobalt carbonyl ionic liquids. Furthermore, the addition of ligands during the synthesis phase reduces the number of process steps and facilitates industrial synthesis. This cobalt carbonyl ionic liquid, as a catalyst, can hydroesterify ethylene oxide under mild conditions and can be used to prepare various β-hydroxypropionic esters, particularly methyl 3-hydroxypropionate.

[0009] To achieve the above object, the present invention adopts the following technical solutions: The present invention provides a method for synthesizing a cobalt carbonyl ionic liquid. The method comprises the following steps: placing dicobalt octacarbonyl, a ligand, and an ionic liquid RCl in a closed reaction kettle, wherein the molar ratio of the dicobalt octacarbonyl, the ligand, and the ionic liquid RCl is (0.4-2):1.2:1.2; replacing the gas in the kettle with CO; adjusting the system pressure to 1-8 MPa; reacting at room temperature for 1-24 h; and filtering to remove a precipitate after the reaction is completed to obtain the cobalt carbonyl ionic liquid R[Co(CO)4].

[0010] The equation for the synthesis method is as follows: .

[0011] Furthermore, the ligand is selected from one of imidazole, pyridine and 3-hydroxypyridine.

[0012] Furthermore, the ionic liquid RCl is selected from one of guanidinium hydrochloride, imidazole hydrochloride and pyridine hydrochloride, and its structural formula is as follows: .

[0013] Furthermore, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 One selected from alkyl, cycloalkyl, arylalkyl, alkenyl and alkynyl.

[0014] The present invention also provides a carbonyl cobalt ionic liquid prepared by the above synthesis method.

[0015] An application of the above-mentioned cobalt carbonyl ionic liquid in the synthesis of β-hydroxypropionate is to carry out a hydroesterification reaction in a CO atmosphere using a cobalt carbonyl organic ionic liquid as a catalyst, adding ethylene oxide and the cobalt carbonyl organic ionic liquid to an organic alcohol as a solvent to prepare β-hydroxypropionate. The reaction formula is as follows: .

[0016] Furthermore, the concentration of the ethylene oxide is 0.001 mol / L~100 mol / L.

[0017] Furthermore, the concentration of the cobalt carbonyl ion solution is 0.0001 mol / L~100 mol / L.

[0018] Furthermore, the organic alcohol is selected from one of methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, cyclopentanol, cyclohexanol, benzyl alcohol and phenol.

[0019] Furthermore, the hydroesterification reaction is carried out at a temperature of 40-80°C, a pressure of 2-6 MPa, and a time of 1-24 h.

[0020] The beneficial effects of the present invention are: (1) The preparation process of carbonyl cobalt metal organic ionic liquid is simple, water and oxygen are stable, the catalytic efficiency is high, and the catalyst is easy to separate and recover after the reaction and can be recycled; (2) The product β-hydroxypropionate has extremely high application value, especially methyl 3-hydroxypropionate, which can be used in the large-scale production of 1,3-propylene glycol; (3) The reaction raw materials are bulk chemicals ethylene oxide and carbon monoxide, which are widely available and have mature preparation processes; (4) The conversion rate and selectivity of the ethylene oxide hydroesterification reaction can reach up to 98%, and the final yield of β-hydroxypropionate can reach up to 98%. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the nuclear magnetic spectrum of the tetramethylguanidinocobalt carbonyl ionic liquid in Example 1.

[0022] Figure 2 This is the nuclear magnetic spectrum of the 1,1-dimethyl-3,3-diethylguanidinocobalt carbonyl ionic liquid in Example 2. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. The exemplary implementation methods of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0024] Example 1 A 50 mL autoclave was used. 1.0 mmol Co2CO8, 1.2 mmol tetramethylguanidine hydrochloride, and 1.2 mmol imidazole were first added to the autoclave in a nitrogen atmosphere. The gas in the autoclave was replaced with CO three times to fill the autoclave with CO. The system pressure was then adjusted to 6.0 MPa. The reaction was allowed to proceed at room temperature for 3 h. After the reaction was completed, the precipitate was removed by filtration to obtain an imidazole solution of tetramethylguanidine cobalt carbonyl ionic liquid. The structure is as follows: .

[0025] 1 H NMR (400 MHz, DMSO): δ 7.75 (s, 2H), 2.89 (s, 12H).

[0026] In a 100 ml autoclave, an imidazole solution of tetramethylguanidinocobalt carbonyl ionic liquid (1.0 mmol), methanol (20 ml), and ethylene oxide (200 mmol) were added. The gas in the autoclave was replaced with CO three times to fill the autoclave with CO. The system pressure was then adjusted to 5.0 MPa, and the reaction was heated to 40°C for 15 h. After the reaction, the reaction stock solution was analyzed by GC. The results are shown in Table 1.

[0027] Example 2 A 50 mL high pressure reactor was used to firstly react 1.0 mmol Co2CO8, 1.2 mmol 1,1,-dimethyl-3,3-diethylguanidinium hydrochloride (synthesis method refer to Chinese J. Catal, 2017, 38 , 805–812), 1.2 mmol imidazole was added to an autoclave in a nitrogen environment, and the gas in the reactor was replaced with CO three times to fill the reactor with CO. Then, the system pressure was adjusted to 6.0 MPa and the reaction was carried out at room temperature for 3 h. After the reaction, the precipitate was removed by filtration to obtain an imidazole solution of 1,1,-dimethyl-3,3-diethylguanidinocobaltcarbonyl ionic liquid, the structure of which is as follows: .

[0028] 1 H NMR (400 MHz, CDCl3): δ 7.85 (s, 2H), 3.26 (s, 4H), 2.90 (s, 6H), 1.10 (s, 6H).

[0029] In a 100 ml autoclave, an imidazole solution of 1,1-dimethyl-3,3-diethylguanidinocobalt carbonyl ionic liquid (1.0 mmol), methanol (20 ml), and ethylene oxide (200 mmol) were added. The gas in the reactor was replaced with CO three times to fill the reactor with CO. The system pressure was then adjusted to 5.0 MPa, and the reaction was heated to 40°C for 15 h. After the reaction, the reaction stock solution was analyzed by GC. The results are shown in Table 1.

[0030] Example 3 A 50 mL high pressure reactor was used to firstly react 1.0 mmol Co2CO8, 1.2 mmol 1,1,-dimethyl-3,3-di-n-butylguanidinium hydrochloride (synthesis method refers to Chinese J. Catal, 2017, 38 , 805–812), 1.2 mmol imidazole was added to an autoclave in a nitrogen atmosphere, and the gas in the reactor was replaced with CO three times to fill the reactor with CO. Then, the system pressure was adjusted to 6.0 MPa, and the reaction was carried out at room temperature for 3 h. After the reaction, the precipitate was removed by filtration to obtain an imidazole solution of 1,1,-dimethyl-3,3-di-n-butylguanidinocobaltcarbonyl ionic liquid, the structure of which is as follows: .

[0031] 1 H NMR (500 MHz, DMSO): δ 8.22(s, 2H), 3.28 (t, 4H), 2.97 (s, 6H), 1.54 (m, 4H) 1.30 (m, 4H), 0.94 (t, 6H).

[0032] In a 100 ml autoclave, an imidazole solution of 1,1-dimethyl-3,3-di-n-butylguanidinocobalt carbonyl ionic liquid (1.0 mmol), methanol (20 ml), and ethylene oxide (200 mmol) were added. The gas in the reactor was replaced with CO three times to fill the reactor with CO. The system pressure was then adjusted to 5.0 MPa, and the reaction was heated to 40°C for 15 h. After the reaction, the reaction stock solution was analyzed by GC. The results are shown in Table 1.

[0033] Example 4 A 50 mL autoclave was used. 1.0 mmol Co2CO8, 1.2 mmol 1-methylimidazole hydrochloride, and 1.2 mmol imidazole were first added to the autoclave in a nitrogen atmosphere. The gas in the autoclave was replaced with CO three times to fill the autoclave with CO. The system pressure was then adjusted to 6.0 MPa. The reaction was allowed to proceed at room temperature for 3 h. After the reaction was completed, the precipitate was removed by filtration to obtain an imidazole solution of 1-methylimidazole cobalt carbonyl ionic liquid. The structure is as follows: .

[0034] 1 H NMR (300 MHz, CD2Cl2): δ 8.80 (s,1H), 8.32 (s, 1H), 4.02 (s, 3H).

[0035] In a 100 ml autoclave, an imidazole solution (1.0 mmol) of 1-ethyl-3-methylimidazolium carbonyl cobalt ionic liquid, methanol (20 ml), and ethylene oxide (200 mmol) were added. The gas in the autoclave was replaced with CO three times to fill the autoclave with CO. The system pressure was then adjusted to 5.0 MPa, and the reaction was heated to 40°C for 15 h. After the reaction, the reaction stock solution was analyzed by GC. The results are shown in Table 1.

[0036] Example 5 A 50 mL autoclave was used. 1.0 mmol Co2CO8, 1.2 mmol 1-butyl-3-methylimidazolium hydrochloride, and 1.2 mmol imidazole were first added to the autoclave in a nitrogen atmosphere. The gas in the autoclave was replaced with CO three times to fill the autoclave with CO. The system pressure was then adjusted to 6.0 MPa. The reaction was allowed to proceed at room temperature for 3 h. After the reaction was completed, the precipitate was removed by filtration to obtain an imidazole solution of 1-butyl-3-methylimidazolium carbonyl cobalt ionic liquid. The structure is as follows: .

[0037] 1 H NMR (400 MHz, CDCl3): δ 8.97 (s, 1H), 7.42 (s, 1H), 4.28 (s, 2H), 4.06 (s, 3H), 1.93 (m, 2H), 1.42 (m, 2H), 0.99 (m, 3H).

[0038] In a 100 ml autoclave, an imidazole solution (1.0 mmol) of 1-butyl-3-methylimidazolium cobalt carbonyl ionic liquid, methanol (20 ml), and ethylene oxide (200 mmol) were added. The gas in the autoclave was replaced with CO three times to fill the autoclave with CO. The system pressure was then adjusted to 5.0 MPa, and the reaction was heated to 40°C for 15 h. After the reaction, the reaction stock solution was analyzed by GC. The results are shown in Table 1.

[0039] Example 6 A 50 mL high pressure reactor was used to firstly add 1.0 mmol Co2CO8, 1.2 mmol N-methylpyridine hydrochloride (synthesis method reference Angew. Chem. Int. Ed. 2023, 62 , e202309519), 1.2 mmol imidazole was added to an autoclave in a nitrogen atmosphere, and the gas in the autoclave was replaced with CO three times to fill the autoclave with CO. The system pressure was then adjusted to 6.0 MPa, and the reaction was carried out at room temperature for 3 h. After the reaction, the precipitate was removed by filtration to obtain an imidazole solution of N-methylpyridine hydrochloride cobalt carbonyl ionic liquid, the structure of which is as follows: .

[0040] 1 H NMR (400 MHz, acetone-d 6 ): δ 9.13 (d, 2H), 8.73 (t, 1H), 8.27 (t, 2H), 4.65 (s, 3H).

[0041] In a 100 ml autoclave, an imidazole solution (1.0 mmol) of N-methylpyridine hydrochloride carbonyl cobalt ionic liquid, methanol (20 ml), and ethylene oxide (200 mmol) were added. The gas in the autoclave was replaced with CO three times to fill the autoclave with CO. The system pressure was then adjusted to 5.0 MPa, and the reaction was heated to 40°C for 15 h. After the reaction, the reaction stock solution was analyzed by GC. The results are shown in Table 1.

[0042] Example 7 A 50 mL high pressure reactor was used to firstly add 1.0 mmol Co2CO8, 1.2 mmol N-butylpyridine hydrochloride (synthesis method reference RSC Adv. 2015, 5, 32839–32845), 1.2 mmol imidazole was added to an autoclave in a nitrogen atmosphere, and the gas in the autoclave was replaced with CO three times to fill the autoclave with CO. The system pressure was then adjusted to 6.0 MPa, and the reaction was carried out at room temperature for 3 h. After the reaction, the precipitate was removed by filtration to obtain an imidazole solution of N-butylpyridinium hydrochloride carbonyl cobalt ionic liquid, the structure of which is as follows: .

[0043] 1 H NMR (400 MHz, acetone-d 6 ): δ 9.053 (m, 2H), 8.640 (m, 1H), 8.175 (m, 2H), 4.478 (m, 2H), 2.040 (m, 2H), 1.377 (m, 2H), 0.895 (m, 3H).

[0044] In a 100 ml autoclave, an imidazole solution (1.0 mmol) of N-butylpyridinium hydrochloride carbonyl cobalt ionic liquid, methanol (20 ml), and ethylene oxide (200 mmol) were added. The gas in the reactor was replaced with CO three times to fill the reactor with CO. The system pressure was then adjusted to 5.0 MPa, and the reaction was heated to 40°C for 15 h. After the reaction, the reaction stock solution was analyzed by GC. The results are shown in Table 1.

[0045] Example 8 The imidazole used in Example 1 was replaced with pyridine, and other operating conditions remained unchanged. After the reaction was completed, the reaction stock solution was analyzed by GC. The results are shown in Table 1.

[0046] Example 9 The imidazole used in Example 1 was replaced with 3-hydroxypyridine, and other operating conditions remained unchanged. After the reaction was completed, the reaction stock solution was analyzed by GC. The results are shown in Table 1.

[0047] Example 10 The amount of the carbonyl cobalt ionic liquid in Example 1 was changed to 0.8 mmol, and the other operating conditions remained unchanged. After the reaction was completed, the reaction stock solution was analyzed by GC. The results are shown in Table 1.

[0048] Example 11 The amount of the cobalt carbonyl ionic liquid in Example 1 was changed to 0.4 mmol, and the other operating conditions remained unchanged. After the reaction was completed, the reaction stock solution was analyzed by GC. The results are shown in Table 1.

[0049] Example 12 The amount of the carbonyl cobalt ionic liquid in Example 1 was changed to 2 mmol, and the other operating conditions remained unchanged. After the reaction was completed, the reaction stock solution was analyzed by GC. The results are shown in Table 1.

[0050] Example 13 The hydroesterification reaction temperature in Example 1 was changed from 40° C. to 50° C., with other operating conditions remaining unchanged. After the reaction was completed, the reaction stock solution was analyzed by GC. The results are shown in Table 1.

[0051] Example 14 The hydroesterification reaction temperature in Example 1 was changed from 40° C. to 70° C., with other operating conditions remaining unchanged. After the reaction was completed, the reaction stock solution was analyzed by GC. The results are shown in Table 1.

[0052] Example 15 The hydroesterification reaction temperature in Example 1 was changed from 40° C. to 80° C., with other operating conditions remaining unchanged. After the reaction was completed, the reaction stock solution was analyzed by GC. The results are shown in Table 1.

[0053] Example 16 The hydroesterification reaction pressure in Example 1 was changed from 4.0 MPa to 2.0 MPa, while other operating conditions remained unchanged. After the reaction was completed, the reaction stock solution was analyzed by GC. The results are shown in Table 1.

[0054] Example 17 The hydroesterification reaction pressure in Example 1 was changed from 4.0 MPa to 3.0 MPa, while other operating conditions remained unchanged. After the reaction was completed, the reaction stock solution was analyzed by GC. The results are shown in Table 1.

[0055] Example 18 The amount of methanol used in Example 1 was changed from 20 mL to 40 mL, and other operating conditions remained unchanged. After the reaction was completed, the reaction stock solution was analyzed by GC. The results are shown in Table 1.

[0056] Example 19 The hydroesterification reaction time in Example 1 was changed from 15 h to 4 h, with other operating conditions remaining unchanged. After the reaction was completed, the reaction stock solution was subjected to GC analysis. The results are shown in Table 1.

[0057] Example 20 The hydroesterification reaction time in Example 1 was changed from 15 h to 8 h, while other operating conditions remained unchanged. After the reaction was completed, the reaction stock solution was subjected to GC analysis. The results are shown in Table 1.

[0058] Example 21 The hydroesterification reaction time in Example 1 was changed from 15 h to 12 h, while other operating conditions remained unchanged. After the reaction was completed, the reaction stock solution was analyzed by GC. The results are shown in Table 1.

[0059] Example 22 The hydroesterification reaction time in Example 1 was changed from 15 h to 16 h, while other operating conditions remained unchanged. After the reaction was completed, the reaction stock solution was subjected to GC analysis. The results are shown in Table 1.

[0060] Example 23 The hydroesterification reaction time in Example 1 was changed from 15 h to 24 h, while other operating conditions remained unchanged. After the reaction, the reaction stock solution was analyzed by GC. The results are shown in Table 1.

[0061] Example 24 After the reaction in Example 1 was completed, the reaction solution was distilled under reduced pressure to remove the solvent and methyl β-hydroxypropionate, and the remaining liquid was transferred back into a 100 ml autoclave, methanol (20 ml), ethylene oxide (200 mmol), and the gas in the autoclave was replaced with CO three times to fill the autoclave with CO. Then, the system pressure was adjusted to 5.0 MPa, heated to 40°C, and reacted for 15 hours. After the reaction was completed, the reaction stock solution was analyzed by GC. The results are shown in Table 1.

[0062] Example 25 After the reaction of Example 24, the reaction solution was distilled under reduced pressure to remove the solvent and methyl β-hydroxypropionate, and the remaining liquid was transferred back into a 100 ml autoclave, methanol (20 ml), ethylene oxide (200 mmol), and the gas in the autoclave was replaced with CO three times to fill the autoclave with CO. The system pressure was then adjusted to 5.0 MPa, heated to 40°C, and reacted for 15 h. After the reaction, the reaction stock solution was analyzed by GC. The results are shown in Table 1.

[0063] As shown in Table 1, the conversion rate of the ethylene oxide hydroesterification reaction can reach up to 98%, and the final yield of β-hydroxypropionate can reach up to 98%. A comparison of Example 24 and Example 25 shows that the catalyst can be recycled after the reaction.

[0064] Table 1 The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A method for synthesizing a cobalt carbonyl ionic liquid, characterized in that: Octacarbonyl dicobalt, a ligand, and an ionic liquid RCl were placed in a closed reactor, wherein the molar ratio of the octacarbonyl dicobalt, the ligand, and the ionic liquid RCl was (0.4-2):1.2:1.

2. The gas in the reactor was replaced with CO, and the system pressure was adjusted to 1-8 MPa, and the reaction was carried out at room temperature for 1-24 h. After the reaction was completed, the precipitate was removed by filtration to obtain the carbonyl cobalt ionic liquid R[Co(CO)4].

2. The method for synthesizing the cobalt carbonyl ionic liquid according to claim 1, wherein: The ligand is selected from one of imidazole, pyridine and 3-hydroxypyridine.

3. The method for synthesizing the cobalt carbonyl ionic liquid according to claim 1, wherein: The ionic liquid RCl is selected from one of guanidinium hydrochloride, imidazole hydrochloride and pyridine hydrochloride, and its structural formula is as follows: 。 4. The method for synthesizing the cobalt carbonyl ionic liquid according to claim 3, wherein: R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 One selected from alkyl, cycloalkyl, arylalkyl, alkenyl and alkynyl.

5. The cobalt carbonyl ionic liquid prepared by the synthesis method according to any one of claims 1 to 4.

6. Use of the cobalt carbonyl ionic liquid according to claim 5 in the synthesis of β-hydroxypropionate, characterized in that: In a CO atmosphere, using carbonyl cobalt organic ionic liquid as a catalyst, ethylene oxide and carbonyl cobalt organic ionic liquid are added to organic alcohol as a solvent to carry out a hydrogenation reaction to prepare β-hydroxypropionate.

7. The use according to claim 6, characterized in that: The concentration of the ethylene oxide is 0.001 mol / L~100 mol / L.

8. The use according to claim 6, characterized in that: The concentration of the cobalt carbonyl ion solution is 0.04 mol / L~0.1 mol / L.

9. The use according to claim 6, characterized in that: The organic alcohol is selected from one of methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, cyclopentanol, cyclohexanol, benzyl alcohol and phenol.

10. The use according to claim 6, characterized in that: The hydroesterification reaction is carried out at a temperature of 40-80°C, a pressure of 2-6 MPa, and a time of 1-24 h.

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