2, 5-bis (4-fluorobenzoyl) furan and preparation method thereof

Abstract

The invention discloses 2, 5-bis (4-fluorobenzoyl) furan and a preparation method thereof, and belongs to the technical field of small molecule synthesis. The method comprises the following steps: adding fluorobenzene and a Cr-A15 catalyst into a reaction container under the protection of nitrogen, heating the reaction system to 60-75 DEG C, adding 2, 5-furandicarbonyl chloride, reacting at the temperature of 60-80 DEG C until the reaction is finished, cooling the obtained reaction liquid to room temperature, adding DCM, stirring, filtering, collecting the filtrate, and drying to obtain the 2, 5-furandicarbonyl chloride. And carrying out vacuum concentration, recrystallization and vacuum drying to obtain the 2, 5-bis (4-fluorobenzoyl) furan. The Cr-A15 catalyst is used for preparing the BFBF through the Friedel-Crafts acylation reaction, the problems that traditional Lewis acid is difficult to separate, much after-treatment wastewater exists and the like are solved, and the preparation method is simple, effective and high in catalytic efficiency and has important significance on green synthesis of the BFBF.

Description

Technical Field

[0001] The invention belongs to the technical field of small molecule synthesis, and specifically relates to 2,5-bis(4-fluorobenzoyl)furan and a preparation method thereof. Background Art

[0002] In recent years, the development and application of polymer materials has become a hot topic of research, especially the development of high temperature resistant engineering plastics. As a kind of semi-crystalline aromatic thermoplastic polymer, polyaryletherketone (PAEK) can be widely used in high-tech fields such as aerospace, automobile, electronic communication, medical treatment, and industry.

[0003] The aromatic group of PAEK is connected by one or more ether bonds and one or more ketone bonds, such as polyetheretherketone (PEEK), polyetherketone (PEK), polyetherketoneketone (PEKK), polyetherketoneetherketoneketone (PEKEKK), polyetheretherketoneketone (PEEKK), etc. Among them, PEEK has enhanced the flexibility of the chain segment and is easy to crystallize due to the presence of ether bonds in its chain segment. In addition, the presence of the benzene ring structure enhances the rigidity and heat resistance. Therefore, PEEK is a linear aromatic high-temperature resistant thermoplastic. PEEK also has excellent corrosion resistance, wear resistance, hydrolysis resistance, flame retardancy, easy processing, etc., and is called a super heat-resistant thermoplastic resin. Polyetheretherketoneketone (PEEKK) is a high-heat-resistant grade material developed on the basis of PEEK. It maintains the excellent physical properties of PEEK while having a higher heat resistance grade. Traditional PAEK is synthesized from petroleum-based monomers. For example, the monomer 1,4-bis(4-fluorobenzoyl)benzene required for PEEKK is prepared from petroleum-based terephthalic acid (PTA). With the increasing depletion of petroleum resources and the intensification of environmental pollution, the development of bio-based polyaryletherketone is of great significance.

[0004] 2,5-Furandicarboxylic acid (FDCA) is a new type of biomass material produced from renewable resources such as sugar, starch, straw, and agricultural and forestry waste. It is the only bio-based platform molecule with a conjugated aromatic ring structure and is listed as one of the twelve important bio-based platform chemicals by the U.S. Department of Energy. FDCA can be used as a substitute for PTA to participate in various downstream reactions, such as the synthesis of polyesters, polyamides, polyurethanes, and polyaryletherketones. Patent document CN111944143B uses the homemade furan ring-containing dihalogen benzophenone monomer 2,5-bis(4-fluorophenylacyl)furan (BFBF) as a raw material to prepare a bio-based polyaryletherketone resin containing a furan ring. The resin material has relatively excellent heat resistance, solubility, mechanical properties and processability. Yusuke Kanetaka et al. used BFBF and other bisphenol monomers as raw materials to prepare polyaryletherketone containing a furan ring through a nucleophilic substitution reaction. Experiments show that the bio-based polyaryletherketone introduced with a furan ring has good heat resistance, mechanical properties and processability. Therefore, using the bio-based monomer FDCA instead of the petroleum-based monomer PTA to prepare polyaryletherketone is a new research and development direction for the development of thermoplastic polymers.

[0005] BFBF monomer is prepared by Friedel-Crafts reaction with 2,5-furandicarbonyl chloride (FDCl) and fluorobenzene (F-Ph) as raw materials. At present, the literature and patent reports usually use traditional homogeneous catalysts for Friedel-Crafts acylation, such as Lewis acids such as aluminum trichloride, boron tribromide, boron trifluoride, boron trichloride and Brønsted acids such as p-toluenesulfonic acid and phosphoric acid. These traditional catalysts have problems such as large dosage, difficulty in recycling, and large amount of waste liquid generated in post-reaction treatment in Friedel-Crafts acylation. The development of new solid acid catalysts with excellent performance, recyclability, and easy product separation and purification has become a better choice. In recent years, ion exchange resins have been applied to Friedel-Crafts acylation as a new type of solid acid catalyst. Ion exchange resins are used to catalyze this reaction with the advantages of high catalytic efficiency, recyclability, relatively mild reaction conditions, good product selectivity and environmental friendliness, overcoming the disadvantages of traditional Lewis acids such as difficult separation, large amount of post-treatment wastewater, corrosion equipment, and easy hydrolysis.

[0006] Based on this, the present invention develops a loaded Amberlyst-15 resin-metal complex catalyst Cr-A15 for preparing BFBF by Friedel-Crafts acylation reaction. The catalyst has high catalytic efficiency, is easy to recover and has good reusability, and is of great significance for the green synthesis of BFBF. Summary of the invention

[0007] The object of the present invention is to provide 2,5-bis(4-fluorobenzoyl)furan and a preparation method thereof, so as to solve the problems in the prior art that the catalyst for preparing 2,5-bis(4-fluorobenzoyl)furan by Friedel-Crafts acylation is mainly based on common Lewis acid aluminum chloride, and the product yield is low, the post-processing cost is high, the catalyst is not easy to recover, and the environment is not friendly.

[0008] The purpose of the present invention can be achieved through the following technical solutions:

[0009] A method for preparing 2,5-bis(4-fluorobenzoyl)furan comprises the following steps:

[0010] Under nitrogen protection, fluorobenzene (F-Ph) and Cr-A15 catalyst are added to the reaction container, the reaction system is heated to 60°C to 75°C, 2,5-furandicarbonyl chloride (FDCl) is added, and the reaction is carried out at a temperature of 60°C to 80°C until the reaction is completed. The obtained reaction solution is cooled to room temperature (25 to 30°C), dichloromethane (DCM) is added, stirred, and then the filtrate is collected by filtration. After reduced pressure concentration, recrystallization, and vacuum drying, 2,5-bis(4-fluorobenzoyl)furan (BFBF) is obtained.

[0011] As a further embodiment of the present invention, the preparation method of the Cr-A15 catalyst comprises the following steps:

[0012] Chromium dichloride (CrCl2, CAS: 10049-05-5) aqueous solution and Amberlyst-15 resin were placed at 90°C and stirred for 15h to 17h. After the reaction, the product was collected by filtration, washed with deionized water until there was no chloride ion in the filtrate, and vacuum dried to obtain Cr-A15 catalyst.

[0013] As a further solution of the present invention, the content of Cr in the Cr-A15 catalyst is 4wt% to 8wt%.

[0014] As a further embodiment of the present invention, the vacuum drying temperature is 35°C to 45°C.

[0015] As a further solution of the present invention, the filtrate uses silver nitrate with a mass concentration of 1% as an indicator to detect chloride ions.

[0016] As a further solution of the present invention, the amount of the Cr-A15 catalyst used is 10wt% to 20wt% of the mass of 2,5-furandicarboxylic acid chloride.

[0017] As a further embodiment of the present invention, the molar ratio of fluorobenzene to 2,5-furandicarboxylic acid chloride is 3 to 6:1.

[0018] As a further embodiment of the present invention, the reaction time is 1.5 h to 4.5 h.

[0019] As a further embodiment of the present invention, the recrystallization process is carried out in a mixed solution consisting of toluene and n-hexane in a volume ratio of 1:1.

[0020] As a further embodiment of the present invention, the vacuum drying temperature is 45°C to 55°C.

[0021] A 2,5-bis(4-fluorobenzoyl)furan is prepared by the above preparation method.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention adopts a resin-metal complex catalyst Cr-A15 catalyst instead of a traditional Lewis acid catalyst such as AlCl3 for preparing 2,5-bis(4-fluorobenzoyl)furan in an acylation reaction. In the preparation process, fluorobenzene is used as both a reaction solvent and a reactant to participate in the Friedel-Crafts acylation reaction, and no additional organic solvent is needed, which effectively improves the utilization rate of the reactants and thus improves the purity and yield of the product. The present invention has the advantages of being environmentally friendly, having high catalytic efficiency and high safety. In addition, the post-processing process is simple, which reduces equipment cost and energy consumption, and is of great significance to the green synthesis of BFBF.

[0024] 2. The Cr-A15 catalyst provided by the present invention is prepared by loading Cr on Amberlyst-15 resin through complex reaction. The synthesis method is simple, the catalytic efficiency is high and it is easy to recover. It has a rough, porous amorphous structure. 3+ The elements and -SO3H groups give it certain Lewis acidity and Bronsted acidity. This solid acid catalyst can effectively overcome the shortcomings of traditional Lewis acids, such as difficulty in separation, large amount of post-treatment wastewater, corrosion of equipment, and easy hydrolysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below in conjunction with the accompanying drawings.

[0026] Figure 1 It is a schematic diagram of a synthetic route of 2,5-bis(4-fluorobenzoyl)furan of the present invention;

[0027] Figure 2 is a BET characterization diagram of the 8Cr-A15 catalyst prepared in Example 3 of the present invention;

[0028] Figure 38Cr-A15 catalyst prepared in Example 3 of the present invention is a SEM image; wherein (A) is a SEM image of the 8Cr-A15 catalyst at a magnification of 2 μm, and (B) is a SEM image at a magnification of 500 nm;

[0029] Figure 4 is the XPS graph of the 8Cr-A15 catalyst prepared in Example 3 of the present invention;

[0030] Figure 5 is the XRD pattern of the 8Cr-A15 catalyst prepared in Example 3 of the present invention;

[0031] Figure 6 is the FTIR analysis chart of the 8Cr-A15 catalyst prepared in Example 3 of the present invention;

[0032] Figure 7 The figure is the hydrogen nuclear magnetic spectrum of 2,5-bis(4-fluorobenzoyl)furan prepared by the present invention. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] See also Figure 1 , a method for preparing 2,5-bis(4-fluorobenzoyl)furan, comprising the following steps:

[0035] The amount of Cr-A15 catalyst is 10wt% to 20wt% of the mass of FDCl, and the molar ratio of fluorobenzene to FDCl is 3 to 6:1. Under nitrogen protection, fluorobenzene and Cr-A15 catalyst are added to a three-necked flask in sequence, the reaction system is heated to 60°C to 75°C, FDCl is added in batches, and after the addition is completed, the reaction is carried out at 60 to 80°C for 1.5h to 4.5h;

[0036] After the reaction, the obtained reaction solution was naturally cooled to room temperature, DCM was added to the reaction solution, stirred for 10 minutes, and then filtered to obtain a filter cake and a filtrate, and the filter cake was rinsed with DCM until there were no obvious spots on the filtrate spot plate, and all the filtrates were combined and concentrated under reduced pressure to obtain a crude BFBF product; the crude BFBF product was recrystallized in toluene / n-hexane (V / V=1:1), and finally vacuum dried at 45°C to 55°C to obtain a white crystalline product of BFBF.

[0037] It should be noted that in the following embodiments and comparative examples, parameters such as the acceleration rate and stirring rate during the reaction process are adjusted according to the settings of the reactor used; there are no special restrictions as long as they meet industry standards.

[0038] Example 1

[0039] The preparation method of 4Cr-A15 catalyst (Cr content is 4wt%) comprises the following steps:

[0040] Take a 250mL three-necked flask equipped with a reflux tube and a thermometer, add 50mL of deionized water, 0.236g of chromium dichloride and 2.5g of Amberlyst-15 resin in sequence, and stir in a 90°C oil bath for 16h to carry out a complex reaction; after the reaction is completed, filter and collect the product, wash it with deionized water (until there is no chloride ion in the filtrate, that is, no chloride ion can be detected using 1% silver nitrate as an indicator); finally, put it into a vacuum dryer and dry it at a temperature of 40°C to obtain 2.6g of the target product 4Cr-A15 catalyst.

[0041] Example 2

[0042] The preparation method of 6Cr-A15 catalyst (Cr content is 6wt%) comprises the following steps:

[0043] Take a 250mL three-necked flask equipped with a reflux tube and a thermometer, add 50mL of deionized water, 0.378g of chromium dichloride and 2.5g of Amberlyst-15 resin in sequence, and stir in a 90°C oil bath for 16h to carry out a complex reaction; after the reaction is completed, filter and collect the product, wash it with deionized water (until there is no chloride ion in the filtrate, that is, no chloride ion can be detected using 1% silver nitrate as an indicator); finally, put it into a vacuum dryer and dry it at a temperature of 40°C to obtain 2.66g of the target product 6Cr-A15 catalyst.

[0044] Example 3

[0045] The preparation method of 8Cr-A15 catalyst (Cr content is 8wt%) comprises the following steps:

[0046] Take a 250mL three-necked flask equipped with a reflux tube and a thermometer, add 50mL of deionized water, 0.52g of chromium dichloride and 2.5g of Amberlyst-15 resin in sequence, and stir in a 90°C oil bath for 16h to carry out a complex reaction; after the reaction is completed, filter and collect the product, wash it with deionized water (until there is no chloride ion in the filtrate, that is, no chloride ion can be detected using 1% silver nitrate as an indicator); finally, put it into a vacuum dryer and dry it at a temperature of 40°C to obtain 2.72g of the target product 8Cr-A15 catalyst.

[0047] The performance of the 8Cr-A15 catalyst prepared in Example 3 was tested:

[0048] (1) BET (nitrogen adsorption) characterization of 8Cr-A15 catalyst Figure 2 As shown in Figure 2, the BET characterization shows that the prepared material has a mesoporous structure and its BET specific surface area is 7.1 m 2 / g, pore size is 20nm.

[0049] (2) Scanning electron microscopy (SEM) characterization of 8Cr-A15 catalyst Figure 3 As shown, Figure 3 (A) is the SEM image of 8Cr-A15 catalyst at 2 μm magnification. Figure 3 (B) is a SEM image at a magnification of 500nm; it can be seen from the SEM image that the 8Cr-A15 catalyst has a rough, porous structure, which has a significant positive effect on the adsorption of the substrate and the provision of Lewis acid acidity.

[0050] (3) XPS characterization of 8Cr-A15 catalyst Figure 4 As shown, from the XPS graph, it can be seen that the catalyst has Cr, O, S and C elements.

[0051] (4) XRD characterization of 8Cr-A15 catalyst Figure 5 As shown, the broad peaks of XRD show the amorphous morphology of the catalyst, which has an amorphous structure, which makes the catalyst have certain acidity.

[0052] (5) Fourier transform infrared spectroscopy (FTIR) characterization of 8Cr-A15 catalyst is shown in the figure Figure 6 As shown in the figure, FTIR characterization analysis shows that 8Cr-A15 has a peak at 1162 cm -1 The stretching vibration peak of -SO3H is shown at 1007cm -1 、1035cm -1 、1224cm -1 and 1413cm -1 The band at 3431 cm -1 The band at is attributed to the vibration of -OH.

[0053] In summary, the 8Cr-A15 catalyst is a catalyst with a rough, porous, amorphous structure. 3+ The elements and -SO3H groups endow the catalyst with certain Lewis acidity and Bronsted acidity.

[0054] Example 4

[0055] See also Figure 1 , a method for preparing 2,5-bis(4-fluorobenzoyl)furan, comprising the following steps:

[0056] Under nitrogen protection, 4.81 g (0.05 mol) of fluorobenzene and 290 mg of the 6Cr-A15 catalyst prepared in Example 2 were added to a three-necked flask in sequence, the reaction system was heated to 70°C, 1.93 g (0.01 mol) of FDCl was added in batches, and the reaction was carried out at 75°C for 3 h after the addition was completed;

[0057] After the reaction, the obtained reaction solution was naturally cooled to room temperature, 50 mL of DCM was added to the reaction solution and stirred for 10 min, and then filtered to obtain a filter cake and a filtrate. The filter cake was eluted with DCM until there was no obvious spot on the filtrate spot plate, and all the filtrates were combined and concentrated under reduced pressure to obtain a crude BFBF product; the crude BFBF product was recrystallized in toluene / n-hexane (V / V=1:1), and finally vacuum dried at 50°C to obtain a white crystalline product BFBF. The H NMR spectrum of the product BFBF is shown as follows Figure 7 shown.

[0058] Example 5

[0059] A method for preparing 2,5-bis(4-fluorobenzoyl)furan, which differs from Example 4 in that only the catalyst is replaced by the 4Cr-A15 catalyst prepared in Example 1, and the other steps and parameters remain the same.

[0060] Example 6

[0061] A method for preparing 2,5-bis(4-fluorobenzoyl)furan, which differs from Example 4 in that only the catalyst is replaced by the 8Cr-A15 catalyst prepared in Example 3, and the other steps and parameters remain the same.

[0062] Example 7

[0063] A method for preparing 2,5-bis(4-fluorobenzoyl)furan is different from Example 4 in that only the amount of fluorobenzene is replaced with 2.88 g (0.03 mol), and the other steps and parameters remain the same.

[0064] Example 8

[0065] A method for preparing 2,5-bis(4-fluorobenzoyl)furan, which is different from Example 4 in that only the reaction temperature is replaced with 60° C., and the other steps and parameters remain the same.

[0066] Example 9

[0067] A method for preparing 2,5-bis(4-fluorobenzoyl)furan, which is different from Example 4 in that only the reaction temperature is replaced with 80° C., and the other steps and parameters remain the same.

[0068] Example 10

[0069] A method for preparing 2,5-bis(4-fluorobenzoyl)furan, which is different from Example 4 in that only the reaction time is replaced with 1.5 h, and the other steps and parameters remain the same.

[0070] Embodiment 11

[0071] A method for preparing 2,5-bis(4-fluorobenzoyl)furan is different from Example 4 in that only the reaction time is replaced with 4.5 h, and the other steps and parameters remain the same.

[0072] Example 12

[0073] A method for preparing 2,5-bis(4-fluorobenzoyl)furan is different from Example 4 in that only the amount of 6Cr-A15 catalyst is replaced with 386 mg, and the other steps and parameters remain the same.

[0074] Example 13

[0075] A method for preparing 2,5-bis(4-fluorobenzoyl)furan is different from Example 4 in that only the amount of 6Cr-A15 catalyst is replaced with 193 mg, and the other steps and parameters remain the same.

[0076] Comparative Example 1

[0077] A method for preparing 2,5-bis(4-fluorobenzoyl)furan is different from Example 4 in that only the 6Cr-A15 catalyst is replaced with an equal mass of Amberlyst-15 resin, and the other steps and parameters remain the same.

[0078] The yield and purity of the white crystalline product BFBF prepared by Examples 1 to 13 and Comparative Example 1 are shown in Table 1.

[0079] Table 1

[0080]

[0081] It can be seen from Table 1 that, by comparing Example 4 with Comparative Example 1, the catalytic activity of Amberlyst-15 can be effectively improved by adopting the Cr-modified complexation method, and the catalytic efficiency can be improved, thereby further improving the BFBF yield; in addition, the solid acid catalyst Cr-A15 used in the present invention to catalyze the preparation of BFBF has a high catalytic activity, the yield can be improved by changing the reaction conditions, and the post-reaction treatment is simple, which is of great significance for the green preparation of BFBF.

[0082] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0083] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing 2,5-bis(4-fluorobenzoyl)furan, characterized in that: The following steps are involved: Under nitrogen protection, fluorobenzene and Cr-A15 catalyst were added to the reaction vessel, the reaction system was heated to 60°C-75°C, 2,5-furandicarbonyl chloride was added, and the reaction was carried out at a temperature of 60°C-80°C until the reaction was completed. The obtained reaction solution was cooled to room temperature, DCM was added and stirred, and the filtrate was collected by filtration. After reduced pressure concentration, recrystallization and vacuum drying, 2,5-bis(4-fluorobenzoyl)furan was obtained.

2. The method for preparing 2,5-bis(4-fluorobenzoyl)furan according to claim 1, characterized in that: The preparation method of the Cr-A15 catalyst comprises the following steps: The chromium dichloride aqueous solution and Amberlyst-15 resin were placed at 90°C and stirred for 15h to 17h. After the reaction, the product was collected by filtration, washed with deionized water until there was no chloride ion in the filtrate, and vacuum dried to obtain the Cr-A15 catalyst.

3. A method for preparing 2,5-bis(4-fluorobenzoyl)furan according to claim 2, characterized in that: In the Cr-A15 catalyst, the content of Cr is 4wt% to 8wt%.

4. The method for preparing 2,5-bis(4-fluorobenzoyl)furan according to claim 2, characterized in that: The vacuum drying temperature is 35°C to 45°C.

5. The method for preparing 2,5-bis(4-fluorobenzoyl)furan according to claim 1, characterized in that: The amount of the Cr-A15 catalyst used is 10wt% to 20wt% of the mass of 2,5-furandicarboxylic acid chloride.

6. The method for preparing 2,5-bis(4-fluorobenzoyl)furan according to claim 1, characterized in that: The molar ratio of the fluorobenzene to the 2,5-furandicarboxylic acid chloride is 3 to 6:

1.

7. The method for preparing 2,5-bis(4-fluorobenzoyl)furan according to claim 1, characterized in that: The reaction time is 1.5h to 4.5h.

8. The method for preparing 2,5-bis(4-fluorobenzoyl)furan according to claim 1, characterized in that: The recrystallization process is carried out using a mixed solution consisting of toluene and n-hexane in a volume ratio of 1:

1.

9. The method for preparing 2,5-bis(4-fluorobenzoyl)furan according to claim 1, characterized in that: The vacuum drying temperature is 45°C to 55°C.

10. A 2,5-bis(4-fluorobenzoyl)furan, characterized in that: Prepared by the preparation method described in claim 1.

Images