Metal complex-carbonyl catalysts based on n-based covalent organic frameworks, methods of making and using the same

Abstract

The application discloses a metal complex-carbonyl catalyst based on N-based covalent organic framework and a preparation method and application thereof, and belongs to the technical field of epoxide carbonylation reactions.The catalyst is composed of a metal-complexed N-based covalent organic framework material and a metal carbonyl compound, the metal-complexed N-based covalent organic framework material is composed of an N-based covalent organic framework carrier and a coordinated metal species, the N-based covalent organic framework carrier or the metal-complexed N-based covalent organic framework material can be prepared by a one-step method, other metal species need not be added as a polymerization catalyst, the porosity of the material is favorable to mass transfer and diffusion in the carbonylation process, and the carbonylation activity is improved.The catalyst has considerable activity, selectivity and stability in the process of catalyzing the conversion of epoxide into beta-lactone, and lays a foundation for the industrial application of the epoxide carbonylation reaction.

Description

Technical Field

[0001] This invention belongs to the field of epoxide carbonylation reaction technology, specifically relating to the preparation of metal complex-carbonyl catalysts based on N-based covalent organic frameworks and their application in ring-expansion carbonylation to prepare β-lactones. Background Technology

[0002] β-lactones are important intermediates in the chemical industry, serving as crucial monomers for the synthesis of chemical products such as succinic anhydride, succinic acid, β-hydroxy acids, acrylic acid, and poly(β-hydroxy fatty acid esters) (PHA). PHAs possess numerous excellent properties, particularly their biodegradability in the ocean, leading to their widespread application in biodegradable materials and food packaging. Consequently, industrial demand for β-lactones is increasing; however, the synthesis of β-lactones presents certain challenges, limiting their industrial applications.

[0003] The carbonylation of epoxides is an important route for the synthesis of β-lactones. Most reported catalysts are homogeneous, such as the (Ph3P=)2NCo(CO)4+BF3·Et2O catalyst from Alper's group and the Co2(CO)8 / AlR3 (R=Me, Et, Bu) catalyst from Rieger's group; however, their catalytic performance is not ideal. The most classic homogeneous catalyst is the classic homogeneous bimetallic [Lewis acid] developed by Coates' group. + [Co(CO)4] - Lewis acids are catalysts that form mononuclear metal complexes with metals at the metal center, using porphyrin (TPP) derivatives, salen derivatives, and phthalocyanine derivatives as ligands. These complexes utilize N and O atoms to form the metal. This system exhibits significant advantages such as selectivity and high activity. Homogeneous Lewis acid. + [Co(CO)4] - The reaction mechanism of catalyst-catalyzed carbonylation of epoxides is as follows: (1) [Lewis acid] + (2) [Co(CO)4] Activated epoxides; - (2) The activated epoxide is attacked to form an open-ring intermediate; (3) CO is inserted into the Co-alkyl bond to form a Co-acyl bond; (4) the ring is closed to release the catalyst and form a β-lactone. However, the homogeneous process has always faced the major technical problem of catalyst separation. Homogeneous heterogeneousization is expected to solve this problem. Currently, there are few reported heterogeneous carbonylation systems, and their activity is low (generally only 10-20 h). -1The preparation of Lewis acid generally involves two strategies (both requiring two steps): one is to polymerize first and then coordinate with the metal species, and the other is to coordinate with the metal species first and then polymerize. Currently, two aspects of work are of great significance: (1) developing new heterogeneous catalysts to improve carbonylation activity; (2) simplifying the preparation process of heterogeneous catalysts and developing simple, efficient, and high-yield preparation processes. On the other hand, covalent organic frameworks generally use metal species such as FeCl3, AlCl3, Pd(PPh3)4, and Pd(PPh3)2Cl2 as polymerization catalysts. Among them, the amount of FeCl3 and AlCl3 added is generally 0.5-3 times the mass of the polymer monomer, and some may remain in the polymer. Although the amount of Pd complex catalyst is small, the cost is high, and there may also be a small amount of residue. Therefore, the use of polymerization catalysts is disadvantageous in terms of both polymer purity and preparation cost. Summary of the Invention

[0004] To address the technical problems described in the background section, this invention provides the preparation of a metal complex-carbonyl catalyst based on an N-based covalent organic framework and its application in the catalytic ring-expansion carbonylation of epoxides to prepare β-lactones. The catalyst of this invention consists of two parts: a metal-coated N-based covalent organic framework and a metal carbonyl compound. The metal-coated N-based covalent organic framework comprises an N-based covalent organic framework support and a coordinated metal species. The N-based covalent organic framework support or the metal-coated N-based covalent organic framework can be prepared in a one-step process without the need to add other metal species as polymerization catalysts. The porosity of the material facilitates substrate enrichment, further accelerating the carbonylation activity. This type of catalyst exhibits considerable activity, selectivity, and stability in the catalytic conversion of epoxides to β-lactones, laying the foundation for the industrial application of epoxide carbonylation reactions.

[0005] The technical solution of the present invention is as follows:

[0006] This invention provides a metal-carbonyl catalyst based on an N-based covalent organic framework for heterogeneous carbonylation reactions of epoxides. The catalyst comprises two parts: a metal-coordinated N-based covalent organic framework material and a metal carbonyl compound. The N-based covalent organic framework material is prepared by reacting a poly(aldehyde) compound with a pyrrole compound. The coordinating metal of the N-based covalent organic framework material is one or more of Ti, Ga, Cr, Al, and Mg. The precursor of the metal carbonyl compound is M. 1 x [M 2 (CO) w ], where M 1 M is an alkali metal. 2 For Co.

[0007] Based on the above technical solution, the polyaldehyde compound is further defined as one of terephthalaldehyde, isophthalaldehyde, 1,3,5-benzenetriformaldehyde, 4,4'-biphenyldiformaldehyde, 1,3,5-tris(p-formylphenyl)benzene, or trialdehyde-resenzinol; the pyrrole compound is one of pyrrole, 2,5-dimethylpyrrole, indole, or 5-bromo-4-azaindole; and the coordinating metal precursor is one of TiCl4, GaCl3, CrCl2, CrCl3, AlCl3, diethylaluminum chloride, MgCl2, or MgSO4.

[0008] Based on the above technical solution, further, the loading of the coordination metal of the N-based covalent organic framework in the catalyst is 0.5-3 wt%, and the loading of Co is 0.5-3 wt%.

[0009] Another aspect of the present invention provides a method for preparing the above-mentioned metal complex-carbonyl catalyst based on an N-based covalent organic framework, comprising the following steps: under an inert atmosphere, a metal carbonyl compound precursor is dissolved in solvent 1, and then a metal-coordinated N-based covalent organic framework material is added; the mixture is stirred at -80 to 100°C for 0.5 to 72 h; after washing, filtration, and drying, the metal complex-carbonyl catalyst based on an N-based covalent organic framework is obtained.

[0010] Based on the above technical solution, the metal carbonyl compound precursor is one of Na[Co(CO)4] and K[Co(CO)4]; the solvent 1 is one of tetrahydrofuran, methanol, ethanol, and ethylene glycol dimethyl ether.

[0011] Based on the above technical solution, the preparation process of the metal-coordinated N-based covalent organic framework material further includes the following steps:

[0012] Under an inert atmosphere, polyaldehyde compounds, pyrrole compounds and coordinated metal precursors are added to solvent 1, heated to 80-200℃, stirred and refluxed for 5-72h, washed, filtered and dried to obtain metal-coordinated N-based covalent organic framework materials.

[0013] Alternatively, under an inert atmosphere, polyaldehyde compounds and pyrrole compounds are placed in solvent 2, heated to 80–200°C, stirred and refluxed for 5–72 h, washed, filtered, and dried to obtain an N-based covalent organic framework; a coordinated metal precursor is added to solvent 3, dissolved, and then an N-based covalent organic framework is added, impregnated and stirred at 20–200°C for 1–48 h, washed, filtered, and dried to obtain a metal-coordinated N-based covalent organic framework material.

[0014] Solvent 2 is one of acetic acid and propionic acid, and solvent 3 is one of acetic acid, dichloromethane, and N,N-dimethylformamide.

[0015] Based on the above technical solution, the molar ratio of polyaldehyde compounds to pyrrole compounds is further 1:1 to 1:10.

[0016] The present invention also provides the application of the above-mentioned metal complex-carbonyl catalyst based on N-based covalent organic framework in the preparation of β-lactone by ring expansion carbonylation of epoxide.

[0017] Based on the above technical solution, the reactor used in the carbonylation reaction process is a batch reactor; the carbonylation pressure is 1 to 7.0 MPa; and the reaction temperature is 40 to 70 °C.

[0018] Based on the above technical solution, furthermore, the substrates selected for the carbonylation reaction are ethylene oxide (EO) and propylene oxide (PO) or 1,2-epoxybutane (BO), and the molar ratio of substrate to catalyst n EO / n Co =100~5000, n PO / n Co =100~5000, n BO / n Co =100~5000; reaction time is 1~12h; reaction solvent is one of ethylene glycol dimethyl ether and tetrahydrofuran.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) Metal-coordinated N-based covalent organic frameworks can be integrated into one step from the traditional two-step method (one is to polymerize first and then coordinate and complex metal species, and the other is to coordinate and complex metal species first and then polymerize), reducing some post-processing processes and obtaining metal-coordinated N-based covalent organic framework materials in high yield.

[0021] (2) The preparation process of N-based covalent organic framework materials or metal-coordinated N-based covalent organic frameworks does not require the addition of other metal species as polymerization catalysts, which greatly reduces production costs on the one hand and avoids metal impurity species that are difficult to remove from polymers on the other hand.

[0022] (3) The catalyst exhibits high activity and selectivity when catalyzing the carbonylation of epoxides under mild conditions in a batch reactor, which can further promote the industrial application of homogeneous catalysts. Attached Figure Description

[0023] To more clearly illustrate the embodiments of the present invention, the accompanying drawings involved in the embodiments will be briefly described below.

[0024] Figure 1 The activity of the catalyst in Example 8 for catalyzing the carbonylation reaction of PO at different cycle numbers is shown. Detailed Implementation

[0025] The present invention will be described in detail below with reference to the embodiments. However, the implementation of the present invention is not limited thereto. Obviously, the embodiments described below are only some embodiments of the present invention. For those skilled in the art, other similar embodiments can be obtained without creative effort and all fall within the protection scope of the present invention.

[0026] Example 1

[0027] Under an inert atmosphere, 1.1800 g (8.8 mmol) of terephthalaldehyde and 1.1817 g (17.6 mmol) of pyrrole were added to 80 mL of propionic acid solvent, and the mixture was stirred and refluxed at 140 °C for 48 h. After cooling, the reaction solution was filtered and washed with propionic acid, methanol, dichloromethane, and tetrahydrofuran until colorless. The solution was then dried to obtain 1.9018 g of N-based covalent organic framework, with a yield of 93%. 0.1 g of CrCl2 was added to 20 mL of N,N-dimethylformamide, dissolved, and then 1 g of N-based covalent organic framework was added. The mixture was refluxed and stirred at 170 °C for 24 h. After washing and filtration, the solution was dried to obtain 1.011 g of metal-coordinated N-based covalent organic framework material. ICP-OES analysis showed a Cr content of 1.05%. Under an inert atmosphere, Na[Co(CO)4] was dissolved in tetrahydrofuran solvent, and then a metal-coated N-based covalent organic framework material was added. The mixture was stirred at -20°C for 24 h, washed, filtered, and dried to obtain the final carbonylation catalyst 1. The Co content was found to be 2% by ICP-OES.

[0028] Example 2

[0029] Under an inert atmosphere, 1.1800 g (8.8 mmol) of terephthalaldehyde and 1.1817 g (17.6 mmol) of pyrrole were added to 80 mL of propionic acid solvent, and the mixture was stirred and refluxed at 140 °C for 48 h. After cooling, the reaction solution was filtered and washed with propionic acid, methanol, dichloromethane, and tetrahydrofuran until colorless. The solution was then dried to obtain 1.9018 g of N-based covalent organic framework, with a yield of 93%. 0.1084 g of AlCl3 was added to 20 mL of dichloromethane solvent, dissolved, and then 1 g of the N-based covalent organic framework was added. The mixture was stirred at room temperature for 24 h, washed, filtered, and dried to obtain 0.8581 g of metal-coordinated N-based covalent organic framework material. ICP-OES analysis showed an Al content of 1.10%. Under an inert atmosphere, Na[Co(CO)4] was dissolved in tetrahydrofuran solvent, and then a metal-coated N-based covalent organic framework material was added. The mixture was stirred at -20°C for 24 h, washed, filtered, and dried to obtain the final carbonylation catalyst 2. The Co content was determined to be 1.5% by ICP-OES.

[0030] Example 3

[0031] Under an inert atmosphere, 1.1800 g (8.8 mmol) of terephthalaldehyde and 1.1817 g (17.6 mmol) of pyrrole were added to 80 mL of propionic acid solvent, and the mixture was stirred and refluxed at 140 °C for 48 h. After cooling, the reaction solution was filtered and washed with propionic acid, methanol, dichloromethane, and tetrahydrofuran until colorless. The solution was then dried to obtain 1.9018 g of N-based covalent organic framework, with a yield of 93%. 0.1542 g of TiCl4 was added to 20 mL of ethanol, dissolved, and then 1 g of the N-based covalent organic framework was added. The mixture was stirred at room temperature for 48 h, washed, filtered, and dried to obtain 0.7 g of metal-coordinated N-based covalent organic framework material. ICP-OES analysis showed that the Ti content was 0.9%. Under an inert atmosphere, Na[Co(CO)4] was dissolved in methanol, and then a metal-coated N-based covalent organic framework material was added. The mixture was stirred at -20°C for 24 h, washed, filtered, and dried to obtain the final carbonylation catalyst 3. The Co content was found to be 0.8% by ICP-OES.

[0032] Example 4

[0033] Under an inert atmosphere, 1.2328 g of trialdehyde phloroglucinol (5.867 mmol) and 1.1817 g (17.6 mmol) of pyrrole were added to 80 mL of acetic acid solvent, and the mixture was stirred and refluxed at 140 °C for 24 h. After cooling, the reaction solution was filtered and washed with propionic acid, methanol, dichloromethane, and tetrahydrofuran until colorless. The solution was then dried to obtain 1.9928 g of N-based covalent organic framework (95% yield). 1 g of the N-based covalent organic framework, 1.6 g of anhydrous sodium acetate, and 0.3874 g of GaCl3 were added to 120 mL of acetic acid solvent and dissolved completely. The mixture was heated and refluxed at 120 °C for 48 h. After cooling to room temperature, most of the solvent was removed by rotary evaporation. The solution was filtered and washed successively with ice-cold ultrapure water and ice-cold methanol until colorless. The solution was then dried under vacuum to obtain 1.037 g of metal-coordinated N-based covalent organic framework material. ICP-OES analysis showed a Ga content of 1%. Under an inert atmosphere, Na[Co(CO)4] was dissolved in tetrahydrofuran solvent, and then a metal-coated N-based covalent organic framework material was added. The mixture was stirred at -20°C for 24 h, washed, filtered, and dried to obtain the final carbonylation catalyst 4. The Co content was determined to be 1.2% by ICP-OES.

[0034] Example 5

[0035] Under an inert atmosphere, 1.2328 g (5.867 mmol) of trialdehyde phloroglucinol and 1.1817 g (17.6 mmol) of pyrrole were added to 80 mL of propionic acid solvent, and the mixture was stirred and refluxed at 140 °C for 24 h. After cooling, the reaction solution was filtered and washed with propionic acid, methanol, dichloromethane, and tetrahydrofuran until colorless. The solution was then dried to obtain 1.9930 g of N-based covalent organic framework (N-C), with a yield of 95%. 0.0761 g of CrCl₂ was dissolved in 20 mL of N,N-dimethylformamide. After dissolution, 1 g of N-based C-C was added, and the mixture was refluxed and stirred at 170 °C for 24 h. After washing and filtration, the solution was dried to obtain 1.031 g of metal-coordinated N-based C-C material. ICP-OES analysis showed a Cr content of 1.25%. Under an inert atmosphere, Na[Co(CO)4] was dissolved in tetrahydrofuran solvent, and then a metal-coated N-based covalent organic framework material was added. The mixture was stirred at -20°C for 24 h, washed, filtered, and dried to obtain the final carbonylation catalyst 5. The Co content was determined to be 1.5% by ICP-OES.

[0036] Example 6

[0037] Under an inert atmosphere, 1.1800 g (8.8 mmol) of terephthalaldehyde and 1.1817 g (17.6 mmol) of pyrrole were added to 80 mL of propionic acid solvent. The mixture was stirred and refluxed at 140 °C. After the temperature dropped to 80 °C–90 °C, 0.2974 g of CrCl2 was added in several portions, and the mixture was heated and refluxed at 140 °C for 24 h. After the reaction solution cooled, it was transferred to a beaker, 50 mL of ethanol was added, and the mixture was allowed to stand overnight at -20 °C. The mixture was then filtered, washed successively with ice-cold ultrapure water and ice-cold methanol until colorless, and dried under vacuum at 70 °C to obtain 1.9239 g of a metal-coordinated N-based covalent organic framework material. The Cr content was determined to be 1.15% by ICP-OES. Under an inert atmosphere, Na[Co(CO)4] was dissolved in tetrahydrofuran solvent, and then a metal-coated N-based covalent organic framework material was added. The mixture was stirred at -20°C for 24 h, washed, filtered, and dried to obtain the final carbonylation catalyst 6. The Co content was measured to be 1.3% by ICP-OES.

[0038] Example 7

[0039] Under an inert atmosphere, 1.1800 g of isophthalaldehyde and 1.1817 g of pyrrole were added to 80 mL of propionic acid solvent. The mixture was stirred and refluxed at 140 °C for 10 min. After the temperature dropped to 80 °C–90 °C, 0.2974 g of CrCl2 was added in portions, and the mixture was heated and refluxed at 140 °C for 24 h. After the reaction solution cooled, it was transferred to a beaker, 50 mL of ethanol was added, and the mixture was allowed to stand overnight at -20 °C. The mixture was then filtered and washed successively with ice-cold ultrapure water and ice-cold methanol until colorless. After vacuum drying at 70 °C, 1.9307 g of metal-coordinated N-based covalent organic framework material was obtained. The Cr content was determined to be 1.2% by ICP-OES. Under an inert atmosphere, Na[Co(CO)4] was dissolved in tetrahydrofuran solvent, and then a metal-coated N-based covalent organic framework material was added. The mixture was stirred at -20°C for 24 h, washed, filtered, and dried to obtain the final carbonylation catalyst 7. The Co content was determined to be 1.5% by ICP-OES.

[0040] Example 8

[0041] Under an inert atmosphere, 1.2328 g of trialdehyde phloroglucinol and 1.1817 g of pyrrole were added to 80 mL of propionic acid solvent. The mixture was stirred and refluxed at 140 °C for a period of time. After the temperature dropped to 80 °C–90 °C, 0.2974 g of CrCl2 was added in several portions, and the mixture was heated and refluxed at 140 °C for 24 h. After the reaction solution cooled, it was transferred to a beaker, 50 mL of ethanol was added, and the mixture was allowed to stand overnight at -20 °C. The mixture was then filtered and washed successively with ice-cold ultrapure water and ice-cold methanol until colorless. The solution was dried under vacuum at 70 °C to obtain 2.018 g of metal-coordinated N-based covalent organic framework material. The Cr content was determined to be 1.27% by ICP-OES. Under an inert atmosphere, Na[Co(CO)4] was dissolved in tetrahydrofuran solvent, and then a metal-coated N-based covalent organic framework material was added. The mixture was stirred at -20°C for 24 h, washed, filtered, and dried to obtain the final carbonylation catalyst 8. The Co content was determined to be 1.5% by ICP-OES.

[0042] Example 9

[0043] Under an inert atmosphere, 0.9589 g of 1,3,5-benzenetriformaldehyde and 1.1817 g of pyrrole were added to 80 mL of propionic acid solvent. The mixture was stirred and refluxed at 140 °C for a period of time. Then, 0.3042 g of CrCl2 was added in several portions, and the mixture was heated and refluxed for 36 h. After the reaction solution cooled, it was transferred to a beaker, 60 mL of ethanol was added, and the mixture was allowed to stand overnight at -20 °C. The mixture was filtered, washed successively with ice-cold ultrapure water and ice-cold methanol until colorless, and dried under vacuum at 70 °C to obtain 1.8031 g of metal-coated N-based covalent organic framework material. The Cr content was determined to be 1.08% by ICP-OES. Under an inert atmosphere, Na[Co(CO)4] was dissolved in tetrahydrofuran solvent, and then the metal-coated N-based covalent organic framework material was added. The mixture was stirred at -20 °C for 24 h, washed, filtered, and dried to obtain the final carbonylation catalyst 9. The Co content was determined to be 1.35% by ICP-OES.

[0044] Example 10

[0045] Under an inert atmosphere, 0.9589 g of 1,3,5-benzenetriformaldehyde and 1.1817 g of pyrrole were added to 80 mL of propionic acid solvent. The mixture was stirred and refluxed at 140 °C for a period of time. Then, 0.2979 g of MgSO4 was added in batches, and the mixture was heated and refluxed for 48 h. After cooling, the reaction solution was transferred to a beaker, 40 mL of methanol was added, and the mixture was allowed to stand overnight at -20 °C. The mixture was then filtered and washed successively with ice-cold ultrapure water and anhydrous ethanol until colorless. After vacuum drying, 0.8911 g of metal-coated N-based covalent organic framework material was obtained, and the Mg content was determined to be 1.15% by ICP-OES. Under an inert atmosphere, Na[Co(CO)4] was dissolved in ethanol solvent, and then the metal-coated N-based covalent organic framework material was added. The mixture was stirred at -20 °C for 24 h. After washing, filtration, and drying, the final carbonylation catalyst 10 was obtained, and the Co content was determined to be 0.61% by ICP-OES.

[0046] Example 11

[0047] Under an inert atmosphere, 1.2328 g of trialdehyde phloroglucinol and 1.1817 g of pyrrole were added to 100 mL of propionic acid solvent. The mixture was stirred and refluxed at 120 °C for a period of time. After the temperature dropped to 80 °C–90 °C, 0.3227 g of AlCl3 was added in batches, and the mixture was heated and refluxed for 48 h. After the temperature dropped to room temperature, most of the solvent was removed by rotary evaporation. The mixture was filtered and washed successively with ice-cold ultrapure water and ice-cold methanol until colorless. After vacuum drying, 1.907 g of metal-coated N-based covalent organic framework material was obtained, and the Al content was determined to be 1% by ICP-OES. Under an inert atmosphere, Na[Co(CO)4] was dissolved in tetrahydrofuran solvent, and then the metal-coated N-based covalent organic framework material was added. The mixture was stirred at -20 °C for 24 h. After washing, filtration, and drying, the final carbonylation catalyst 11 was obtained, and the Co content was determined to be 1.3% by ICP-OES.

[0048] Example 12

[0049] Under an inert atmosphere, 2.2887 g (5.867 mmol) of 1,3,5-tris(p-formylphenyl)benzene and 1.1817 g (17.6 mmol) of pyrrole were added to 100 mL of propionic acid solvent, and the mixture was stirred and refluxed at 140 °C for 72 h. After cooling, the reaction solution was filtered and washed with propionic acid, methanol, dichloromethane, and tetrahydrofuran until colorless. The solution was then dried to obtain 2.8382 g of N-based covalent organic framework, with a yield of 90%. 0.098 g of diethylaluminum chloride was added to 20 mL of methanol solvent, dissolved, and then 1 g of the N-based covalent organic framework was added. The mixture was stirred at room temperature for 48 h, washed, filtered, and dried to obtain 0.5581 g of metal-coordinated N-based covalent organic framework material. ICP-OES analysis showed an Al content of 0.85%. Under an inert atmosphere, Na[Co(CO)4] was dissolved in ethylene glycol dimethyl ether, and then a metal-coated N-based covalent organic framework material was added. The mixture was stirred at -20°C for 24 h, washed, filtered, and dried to obtain the final carbonylation catalyst 12. The Co content was determined to be 0.9% by ICP-OES.

[0050] Example 13

[0051] Under an inert atmosphere, 2.2887 g (5.867 mmol) of 1,3,5-tris(p-formylphenyl)benzene and 1.1817 g (17.6 mmol) of pyrrole were added to 100 mL of propionic acid solvent. The mixture was stirred and refluxed at 140 °C for a period of time. After the temperature dropped to 80 °C–90 °C, 0.3774 g of CrCl2 was added in several portions, and the mixture was heated and refluxed at 140 °C for 48 h. After the reaction solution cooled, it was transferred to a beaker, 80 mL of ethanol was added, and the mixture was allowed to stand overnight at -20 °C. The mixture was then filtered, washed successively with ice-cold ultrapure water and ice-cold methanol until colorless, and dried under vacuum at 70 °C to obtain 2.018 g of metal-coordinated N-based covalent organic framework material. The Cr content was determined to be 0.8% by ICP-OES. Under an inert atmosphere, K[Co(CO)4] was dissolved in ethylene glycol dimethyl ether solvent, and then a metal-coated N-based covalent organic framework material was added. The mixture was stirred at -20°C for 24 h, washed, filtered, and dried to obtain the final carbonylation catalyst 13. The Co content was determined to be 1.12% by ICP-OES.

[0052] Example 14

[0053] Under an inert atmosphere, 1.850 g (8.8 mmol) of 4,4'-biphenyldicarboxaldehyde and 1.1817 g (17.6 mmol) of pyrrole were added to 80 mL of propionic acid solvent, and the mixture was stirred and refluxed at 140 °C for 48 h. After cooling, the reaction solution was filtered and washed with propionic acid, methanol, dichloromethane, and tetrahydrofuran until colorless, and dried to obtain 1.0018 g of N-based covalent organic framework. 0.1276 g of CrCl3 was added to 20 mL of N,N-dimethylformamide, dissolved, and then 1 g of N-based covalent organic framework was added. The mixture was refluxed and stirred at 170 °C for 48 h, washed, filtered, and dried to obtain a metal-coordinated N-based covalent organic framework material. ICP-OES analysis showed that the Cr content was 0.1%. Under an inert atmosphere, K[Co(CO)4] was dissolved in ethylene glycol dimethyl ether solvent, and then a metal-coated N-based covalent organic framework material was added. The mixture was stirred at -20°C for 24 h, washed, filtered, and dried to obtain the final carbonylation catalyst 14. The Co content was determined to be 0.9% by ICP-OES.

[0054] Comparative Example 1

[0055] The literature Catalysts. 2020, 10, 905 reported that the catalyst POP-Pc'Cr(III)Co(CO)4, with ethylene glycol dimethyl ether as solvent and a substrate-to-catalyst ratio n(Sub.) / n(Cat.) = 200, catalyzed the carbonylation of propylene oxide for 12 h at a CO reaction pressure of 6 MPa and a reaction temperature of 60 °C.

[0056] Comparative Example 2

[0057] The catalyst [(PPP)Cr(THF)2] is reported in ACS Appl. Mater. Interfaces 2019, 11, 18609-18616. + [Co(CO)4] was catalyzed by the carbonylation of propylene oxide for 20 h at a CO reaction pressure of 6 MPa and a reaction temperature of 60 °C, with tetrahydrofuran as the solvent and a substrate-to-catalyst ratio of n(Sub.) / n(Cat.) = 1000.

[0058] Comparative Example 3

[0059] The catalyst [TPPCr(THF)2] is reported in Sci. Rep. 2018, 8, 13243. + [Co(CO)4] - Using tetrahydrofuran as solvent, with a substrate-to-catalyst ratio of n(Sub.) / n(Cat.) = 100, the carbonylation of propylene oxide was catalyzed for 3 h at a CO reaction pressure of 6 MPa and a reaction temperature of 60 °C.

[0060] Example 15

[0061] Application of the catalysts prepared in Examples 1-14 in the preparation of β-lactones from ethylene oxide, propylene oxide and 1,2-epoxybutane.

[0062] The reaction conditions for a batch reactor are as follows: A certain mass of the N-based covalent organic framework metal complex-carbonyl catalyst is weighed and added to a 50 mL reactor. 10 mL of ultra-dry THF is added, along with 1.56 g of ethylene oxide, 2.06 g of propylene oxide, or 2.56 g of 1,2-epoxybutane, where n... EO / n Co =200, n PO / n Co =200, n BO / n Co =200, in Examples 1-14, the reactor was filled with 3.0 MPa of CO and reacted at 60°C for 3 h.

[0063] In addition, the cyclic stability of the catalyst in Example 8 was investigated. The reaction conditions were as follows: In a glove box, the catalyst and product after the catalytic carbonylation reaction of propylene oxide were separated under vacuum at 40–60°C. The separated catalyst was added to the reactor, followed by a certain amount of propylene oxide. The reactor was then purged with CO at 3.0 MPa, and the reaction was carried out at 60°C for 3 hours. The cyclic conditions were the same for each cycle. The cyclic stability of the catalyst carbonylation was tested, and the test results are as follows: Figure 1 As shown.

[0064] Offline liquid chromatography was performed using a DB-1701 capillary column and an FID detector to analyze the content of epoxides and β-lactones.

[0065] The yield, selectivity, and TOF results of carbonylation of β-lactone prepared according to the above procedures are shown in Table 1.

[0066] Table 1. Results of epoxide carbonylation reactions catalyzed by catalysts in Examples 1-14 and Comparisons 1-3

[0067]

[0068]

[0069] Note: [a]n EO / n Co ;[b]n PO / n Co ;[c]n BO / n Co

[0070] The results of the examples and comparative examples show that the catalyst prepared by the one-step method, which consists of a Cr and Al-coated N-based covalent organic framework and a carbonyl cobalt anion, has considerable activity in the carbonylation of ethylene oxide and propylene oxide. While saving the cost of catalyst preparation and separation, it further lays the foundation for the industrial application of epoxide heterogeneous carbonylation to β-lactone.

[0071] The present invention has been described in detail above, but it is not limited to the specific embodiments described herein. Other modifications and variations can be made without departing from the scope of the invention. The scope of the invention is defined by the appended claims.

Claims

1. An N-based covalent organic framework based metal complex-carbonyl catalyst characterized in that, The catalyst is composed of two parts of metal-coordinated N-based covalent organic framework material and metal carbonyl compound, the N-based covalent organic framework material is prepared by reacting polyaldehyde compound and pyrrole compound, the coordination metal of the N-based covalent organic framework material is one or more than two of Ti, Cr and Al, and the metal carbonyl compound precursor is M 1 [M 2 (CO)4], wherein M 1 is an alkali metal, and M 2 is Co. The polyaldehyde compound is one of p-phthalaldehyde, m-phthalaldehyde, 1,3,5-benzene triformaldehyde, 4,4'-diphenyl aldehyde, and trihydroxybenzene.

2. The catalyst according to claim 1, characterized in that, The precursor of the coordination metal is one of TiCl4, CrCl2, CrCl3, AlCl3, and diethyl aluminum chloride.

3. The catalyst of claim 1, wherein The loading amount of the coordination metal of the N-based covalent organic framework in the catalyst is 0.5-3wt%, and the loading amount of Co is 0.5-3wt%.

4. A process for the preparation of the catalyst of any one of claims 1 to 3, comprising the steps of: Under inert atmosphere, the metal carbonyl precursor is dissolved in solvent 1, and then the metal complexed N-based covalent organic framework material is added, and stirred at -80~100 o C for 0.5-72 h, and then washed, filtered, and dried to obtain a metal complex-carbonyl catalyst based on N-based covalent organic framework; the solvent 1 is one of tetrahydrofuran, methanol, ethanol, and ethylene glycol dimethyl ether.

5. The preparation method according to claim 4, characterized in that, The metal carbonyl compound precursor is one of Na[Co(CO)4] and K[Co(CO)4].

6. The preparation method according to claim 4, characterized in that, The preparation process of the metal-complexed N-based covalent organic framework material comprises the following steps: Under inert atmosphere, polyaldehyde compound, pyrrole compound and coordinated metal precursor are added into solvent 1, heated to 80~200 o C, stirred and refluxed for 5-72 h, washed, filtered and dried to obtain metal-coordinated N-based covalent organic framework material; Alternatively, under inert atmosphere, polyaldehyde compound and pyrrole compound are added in solvent 2, heated to 80~200 o C, stirring reflux for 5-72 h, washed, filtered, and dried to obtain N-based covalent organic framework material; before adding the coordinated metal precursor in solvent 3, the N-based covalent organic framework material is dissolved, and after dissolving, the N-based covalent organic framework material is added, 20-200 o C, stirring for 1-48 h, washed, filtered, and dried to obtain metal-coordinated N-based covalent organic framework material; The solvent 2 is one of acetic acid and propionic acid, and the solvent 3 is one of acetic acid, dichloromethane, and N,N-dimethylformamide.

7. The preparation method according to claim 6, characterized in that, The molar ratio of the polyaldehyde compound to the pyrrole compound is 1:1-1:

10.

8. Use of a catalyst as claimed in any one of claims 1 to 3 in the epoxide expansion carbonylation to prepare lactones. β - lactones.​ 9. Use according to claim 8, characterized in that, The reactor used in the carbonylation reaction process is a kettle reactor; the pressure of the carbonylation is 1-7.0 MPa; and the reaction temperature is 40-70 DEG C.

10. Use according to claim 9, characterized in that, The carbonylation reaction is selected from ethylene oxide EO, propylene oxide PO or 1,2-butylene oxide BO, the molar ratio n of the substrate and the catalyst EO / n Co =100~5000, n PO / n Co =100~5000, n BO / n Co =100~5000; the reaction time is 1~12 h; the reaction solvent is one of ethylene glycol dimethyl ether and tetrahydrofuran.

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