Amidated ferrocene derivative as well as preparation method and application thereof

Abstract

The invention discloses an amidated ferrocene derivative as well as a preparation method and application thereof, and belongs to the technical field of aqueous organic flow batteries. Aiming at the condition that the energy storage stability of the ferrocene electrolyte is limited, a bridged water-soluble p-pi amide structure group is introduced to a cyclopentadienyl ring of ferrocene, and the length of a carbon chain is adjusted, so that the molecular electronic effect is optimized, the decomposition reaction of molecules is inhibited, and the ferrocene electrolyte with a stable state-of-charge structure is prepared.

Description

Technical Field

[0001] The invention belongs to the technical field of liquid flow batteries, and in particular relates to an amidated ferrocene derivative and a preparation method and application thereof. Background Art

[0002] Among the existing flow battery technologies, all-vanadium, iron-chromium and zinc-bromine flow batteries have been studied earlier and are relatively mature, but they face many limitations: all-vanadium flow batteries are limited by the cost and reserves of vanadium resources, iron-chromium flow batteries are difficult to improve in efficiency due to the hydrogen evolution reaction and low activity of chromium ions, and zinc-bromine flow batteries have safety hazards due to the capacity attenuation caused by metal ions penetrating the membrane and the corrosiveness of the electrolyte. In contrast, aqueous organic flow batteries, as a new energy storage technology, use safer, more environmentally friendly and cheaper renewable organic materials, such as ferrocene, viologen, nitroxide free radicals, anthraquinone and other derivatives. The materials are widely available and can be obtained in a sustainable way, reducing dependence on limited metal resources and achieving environmental protection. In addition, most aqueous organic flow batteries use neutral sodium chloride and potassium chloride aqueous solutions as supporting electrolytes, which have low requirements for auxiliary materials such as pipes, pumps, and valves. The electrolyte is neutral, non-corrosive, safe, and more suitable for large-scale applications. By optimizing organic active materials through molecular engineering, the energy density and cycle life can be further improved to meet the energy storage needs of energy systems and power grids.

[0003] Ferrocene derivatives, as representative active materials of aqueous organic flow batteries, have become a research hotspot in this field due to their low cost, good electrochemical stability and reversibility. However, the ferrocene center may decompose, which limits its application in aqueous organic flow batteries. Therefore, in-depth research on the intrinsic relationship between the structure and physicochemical properties and electrochemical performance of ferrocene derivatives can provide theoretical guidance for the design of more stable and efficient ferrocene active materials, so as to better meet the actual needs of aqueous organic flow batteries.

[0004] At present, the development of ferrocene derivatives mainly focuses on molecular modification, by regulating the type, position and number of substituents on the ring to optimize key properties such as water solubility, redox potential and stability. However, it is difficult to achieve the comprehensive improvement of water solubility, redox potential and stability at the same time. Summary of the invention

[0005] The purpose of the present invention is to further explore the structural characteristics of ferrocene derivatives, provide an amidated ferrocene derivative and a preparation method and application thereof, so as to solve the problem in the prior art that the ferrocene center is easily decomposed, making ferrocene unstable in the electrolyte.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: An amidated ferrocene derivative, the structural formula is as follows:

[0007] Where p = 1, 2 or 3; A further improvement of the present invention is: A method for preparing the amidated ferrocene derivative comprises the following steps: Step 1, obtaining ferrocenecarbonyl chloride by reacting ferrocenecarboxylic acid and phosgene; Step 2, mixing the carbon chain reactant and ferrocenecarbonyl chloride in dichloromethane, and obtaining a first process solid after the reaction, wherein the structural formula of the first process solid is:

[0008] Where p = 1, 2 or 3; Step 3, reacting the first process solid with methyl iodide to obtain a second process solid, wherein the structural formula of the second process solid is:

[0009] Where p = 1, 2 or 3; Step 4, dissolving the solid from the second process in water, exchanging with a resin, and rotary evaporating to obtain the amidated ferrocene derivative chloride.

[0010] Preferably, in step 1, ferrocenecarboxylic acid and phosgene are respectively dissolved in dichloromethane for reaction, and the molar ratio of ferrocenecarboxylic acid to phosgene is 1:2.

[0011] Preferably, in step 1, the reaction temperature is room temperature and the reaction time is 1.5 to 2 h.

[0012] Preferably, in step 2, the molar ratio of the carbon chain reactant to ferrocenecarbonyl chloride is (3-4):2.

[0013] Preferably, in step 2, during the reaction of the carbon chain reactant and ferrocenecarbonyl chloride, the temperature of the reaction system is 0° C. or room temperature, and the reaction time is 1 to 2 h.

[0014] Preferably, in step 2, when the reaction product p is 2 or 3, the carbon chain reactant is an amine reactant, and the amine reactant is dimethylpropylenediamine or dimethylethylenediamine. The specific reaction process is: The amine reactant is dissolved in dichloromethane to form a mixed solution of the amine reactant and dichloromethane, the mixed solution is mixed with ferrocenecarbonyl chloride, an acyl chloride reaction occurs, and a reaction system is obtained. The reaction system is repeatedly vacuumed and filled with nitrogen for several times, and the reaction system is reacted at 0°C. After the reaction is completed, the dichloromethane is removed to obtain a first solid product.

[0015] Preferably, in step 2, when the reaction product p is 1, the carbon chain reactant is a mixture of dimethylamine and formaldehyde, and the specific reaction process is: Ferrocenecarbonyl chloride and dichloromethane are mixed, ammonia is introduced, dimethylamine and formaldehyde are added, and then water and ethanol are added. Nitrogen is introduced and the mixture is stirred at room temperature for reaction. After the reaction is completed, dichloromethane is removed to obtain a first solid product.

[0016] Preferably, the mixing molar ratio of dimethylamine to formaldehyde is 1:1.

[0017] An application of an amidated ferrocene derivative for preparing a cathode electrolyte in an aqueous liquid flow battery, wherein the concentration of the amidated ferrocene derivative in the cathode electrolyte is 0.05-3 mol / L.

[0018] The present invention has the following beneficial effects: Under the current situation that the energy storage stability of ferrocene electrolytes is limited, the present invention focuses on molecular modification, and optimizes key properties such as water solubility, redox potential and stability by regulating the type, position and number of substituents on the ring. Specifically, it includes the following advantages: (1) The present invention starts from the design of the substituent structure of the ferrocene skeleton and introduces a p-π amide structure of a bridging water-soluble group on the ferrocene ring to enhance the stability of the charged state of the ferrocene molecule and effectively alleviate the degradation of the ferrocene molecule during the redox process.

[0019] (2) Based on the introduction of amide structure, the present invention further regulates the electronic effect of the molecule by changing the length of the carbon chain molecule, thereby inhibiting the decomposition reaction of the molecule and stabilizing the redox potential of the ferrocene derivative, thereby preparing a ferrocene electrolyte with a stable charged state structure.

[0020] (3) Through a simple and efficient synthesis method, a conjugated structure is introduced at the substituent position of the electrolyte molecule to improve the charge stability of the molecule, providing ideas for the development of high-performance organic liquid flow battery electrolytes. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a graph showing the results of hydrogen nuclear magnetic resonance (HNMR) spectrum characterization of the target product in Example 1.

[0022] Figure 2 This is the result of hydrogen nuclear magnetic resonance spectrum characterization of the target product in Example 2.

[0023] Figure 3 This is the result of hydrogen nuclear magnetic resonance spectrum characterization of the target product in Example 3.

[0024] Figure 4 1 is a cyclic voltammetry test curve of the target product in Example 1; Figure 5 2 is a cyclic voltammetry test curve of the target product in Example 2; Figure 6 3 is a cyclic voltammetry test curve of the target product in Example 3; Figure 7 is the redox potential diagram of the target product in Example 1; Figure 8 is the redox potential diagram of the target product in Example 2; Fig. 9 is the redox potential diagram of the target product in Example 3; Fig.10 is a redox potential difference diagram of the target product in Example 1; Fig.11 is a redox potential difference diagram of the target product in Example 2; Fig.12 is a redox potential difference diagram of the target product in Example 3; Fig.13 is the redox current diagram of the target product in Example 1; Fig.14 is the redox current diagram of the target product in Example 2; Fig.15 is the redox current diagram of the target product in Example 3; Fig.16 is a relationship diagram of the scan square root of the target product in Example 1; Fig.17 is a relationship diagram of the scan rate square root of the target product in Example 2; Fig.18 The relationship diagram of the square root of the scan rate of the target product in Example 3; Fig.19 is the charge and discharge curve of the battery assembled in Example 1; Fig. 20 The figure is the cycle number-coulombic efficiency-charge capacity-discharge capacity curve of the battery assembled in Example 1. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with the accompanying drawings: In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0026] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0027] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0028] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0029] The molecular design and structural modification of ferrocene derivatives have a significant effect on their electrochemical properties. For example, by introducing different substituents into the ferrocene molecule, its redox potential and solubility can be adjusted, thereby optimizing its application performance in flow batteries. Therefore, the development of ferrocene derivatives with excellent performance through structural design and molecular modification is of great significance for improving the performance of aqueous organic flow batteries. Based on this idea, the first aspect of the present invention discloses a new type of amidated ferrocene derivative electrolyte material, whose general structural formula is I:

[0030] I Where p = 1, 2 or 3; The structure is designed based on the substituent structure of the ferrocene skeleton. By introducing a p-π amide structure with a bridging water-soluble group on the ferrocene ring and adjusting the length of the carbon chain, the molecular electronic effect is adjusted to inhibit the decomposition of the molecule.

[0031] In a specific embodiment, when p=1, the amidated ferrocene derivative formed has the structural formula II:

[0032] II In a specific embodiment, when p=2, the amidated ferrocene derivative formed has the structural formula III:

[0033] III In a specific embodiment, when p=3, the amidated ferrocene derivative formed has the structural formula IV:

[0034] IV The second aspect of the present invention discloses a method for preparing an amidated ferrocene derivative electrolyte material, the preparation method specifically comprising the following steps: Step 1, preparation of ferrocenecarbonyl chloride Dissolve ferrocenecarboxylic acid in dichloromethane to obtain a ferrocenecarboxylic acid-dichloromethane solution with a concentration of 1 mol / L; dissolve phosgene in dichloromethane to obtain a phosgene-dichloromethane solution with a concentration of 1 mol / L; add the phosgene-dichloromethane solution dropwise to the ferrocenecarboxylic acid-dichloromethane solution, wherein ferrocenecarboxylic acid and phosgene react, and the molar ratio of ferrocenecarboxylic acid to phosgene is 1:2; repeatedly vacuumize and fill with nitrogen to make the entire reaction system in an oxygen-free state, then stir the reaction system in a water bath environment, react at room temperature for 1.5 to 2 h, remove dichloromethane by rotary evaporation after the reaction, add n-pentane to reduce the solubility of the product in the solvent, and the product precipitates as a solid, collect the solution, and remove n-pentane by rotary evaporation to obtain a brown-red liquid, which is ferrocenecarboxylic acid chloride.

[0035] In this step, the hydroxide in the carboxyl group of ferrocenecarboxylic acid is exchanged with the chloride in phosgene. The reaction in this process is as follows:

[0036] Step 2, mix the carbon chain reactant and ferrocenecarbonyl chloride in dichloromethane, wherein the mixing molar ratio of the amine reactant and ferrocenecarbonyl chloride is (3~4):2, to obtain a reaction system. Then stir the reaction system in an ice water bath or at room temperature, react at 0°C or room temperature for 1~2 hours, add deionized water to extract and remove excess dichloromethane after the reaction, collect the organic phase, rotary evaporate and wash with deionized water to obtain the first process solid. Its structural formula is V:

[0037] V Where p = 1, 2 or 3; In this step, the acyl chloride group of ferrocenylcarbonyl chloride reacts with the amine group in the carbon chain reactant to form an amide bond, and the carbon chain reactant also provides a corresponding number of carbon atoms so that a target carbon chain length can be formed.

[0038] Step 3, dissolving the product obtained in step 2 in acetone to obtain a process solution with a concentration of 1 mol / L, repeatedly vacuuming and filling with nitrogen to make the entire reaction system in an oxygen-free state, adding 3-5 mL of iodomethane under stirring in a water bath, and reacting at 25°C for 10-12 h. After the reaction is completed, extracting the organic phase with deionized water (30 mL), rotary evaporation to obtain the second process solid, whose structural formula is VI:

[0039] VI Where p = 1, 2 or 3; Step 4, dissolving the third process solid obtained in step 3 in deionized water, converting the iodine ions of the obtained compound into chloride ions through a chloride ion exchange resin, and washing and drying the product by rotary evaporation to obtain the final target product, whose structural formula is shown in I:

[0040] I Where p = 1, 2 or 3; In some embodiments of the present invention, in step 2, p is different, and the reaction products and reaction processes are different.

[0041] In some specific embodiments, in step 2, when the reaction product p is 2 or 3, the carbon chain reactant is an amine reactant, and the amine reactant is dimethylpropylenediamine or dimethylethylenediamine. In such embodiments, the amine reactant can provide carbon and amide bonds at the same time, and the specific reaction process is:

[0042] The amine reactant is dissolved in dichloromethane to form a mixed solution of the amine reactant and dichloromethane, the mixed solution is mixed with ferrocenecarbonyl chloride, an acyl chloride reaction occurs, and a reaction system is obtained. The reaction system is repeatedly vacuumed and filled with nitrogen for several times, and then the reaction system is reacted at 0°C. After the reaction is completed, the dichloromethane is removed to obtain a first solid product.

[0043] More specifically, when p is 2, the amine reactant is dimethylethylenediamine, and when p is 3, the amine reactant is dimethylpropylenediamine.

[0044] In some specific embodiments, in step 2, when the reaction product p is 1, the amine reactant is a mixture of ammonia, dimethylamine and formaldehyde. The ammonia in such reactants can produce amide bonds through acyl chloride reaction, and formaldehyde provides carbon atoms. The specific reaction process is:

[0045] Ferrocenecarbonyl chloride and dichloromethane are mixed, ammonia is introduced, dimethylamine and formaldehyde are added, and then water and ethanol are added. Nitrogen is introduced and the mixture is stirred at room temperature for reaction. After the reaction is completed, dichloromethane is removed to obtain a first solid product.

[0046] When the amidated ferrocene derivative is used as a positive electrode electrolyte for an aqueous organic liquid flow battery, the above product is dissolved in 10 mL of a 1 mol / L potassium chloride aqueous solution and stirred to form a uniform solution with a concentration of 0.05-3 mol / L to form a positive electrode electrolyte.

[0047] The following is further described in conjunction with specific embodiments.

[0048] Example 1 Step 1, dissolve ferrocenecarboxylic acid (20 mmol) in 20 mL of dichloromethane and pour into a 100 mL round-bottom flask. Dissolve phosgene (40 mmol) in 40 mL of dichloromethane and slowly titrate into the round-bottom flask with a constant pressure funnel to react with ferrocenecarboxylic acid. During this process, the hydroxyl group in the carboxyl group of ferrocenecarboxylic acid is exchanged with the chlorine group in phosgene. Then, the reaction system is placed in an oxygen-free state by three vacuum-filling-nitrogen operations, stirred in a water bath, and reacted at room temperature for 1.5 h. After the reaction is completed, dichloromethane is removed by rotary evaporation, and n-pentane is added to reduce the solubility of the product in the solvent. The product is precipitated as a solid, the solution is collected, and n-pentane is removed by rotary evaporation. If a brown-red liquid is obtained, step 2 is quickly performed.

[0049] Step 2, add the product ferrocenecarbonyl chloride (20 mmol) obtained in step 1 to a 100 mL round-bottom flask in sequence. Dissolve dimethylpropylenediamine (30 mmol) in 50 mL of dichloromethane and slowly titrate it into the round-bottom flask with a constant pressure funnel to react with ferrocenecarbonyl chloride. During this process, the acyl chloride group of ferrocenecarbonyl chloride reacts with the amine group in dimethylpropylenediamine to form an amide bond. Then, vacuumize and fill with nitrogen three times to make the reaction system oxygen-free, stir in an ice-water bath, and keep the reaction at 0°C for 2 h. After the reaction is completed, add deionized water (30 mL) to extract and remove excess dichloromethane, collect the organic phase, rotary evaporate and wash with deionized water (30 mL), and if a brown-red solid A is obtained, proceed to step 3.

[0050]

[0051] The reaction formula is

[0052] Step 3, the product A (20 mmol) obtained in step 2 was dissolved in 20 mL of acetone and poured into a 100 mL round-bottom flask. The reaction system was placed in an oxygen-free state by three vacuum-filling and nitrogen-filling operations. 3 mL of iodomethane was added dropwise under stirring in a water bath, and reacted with the amine group to form a quaternary amine group and then reacted at 25°C for 12 h. After the reaction was completed, the organic phase was extracted with deionized water (30 mL), and a brown-red solid B was obtained by rotary evaporation. The structural formula is shown below:

[0053] The reaction formula is

[0054] Step 4: Dissolve the brown-red solid product B in deionized water and perform ion exchange with a resin. The product is washed by rotary evaporation to obtain the target product C with a yield of 90%. Its H NMR spectrum is shown in the attached figure. Figure 1 shown.

[0055]

[0056] Reactive,

[0057] Weigh 0.016 mmol of the prepared target product C and dissolve it in 8 ml of 1 mol / L KCl solution, shake and stir, and after it forms a uniform solution, prepare it into 2 mmol / L KCl solution. The electrolyte prepared above is subjected to cyclic voltammetry scanning test using a three-electrode system, in which Ag / AgCl is the reference electrode, the Pt electrode is the counter electrode, and the glassy carbon electrode is the working electrode. The scanning rates are 25 mV / s, 64 mV / s, 100 mV / s, 225 mV / s, 400 mV / s and 625 mV / s. And the redox peak potential is fitted with the square root of the scanning rate, and the slope is in the same order of magnitude. At the same time, its redox potential, redox potential difference, and redox current basically do not change with the change of the square root of the scanning rate, as shown in the attached figure. Figure 4 , Figure 7 , Fig.10 , Fig.13 , Fig.16 This proves that the molecule has reversible electrochemical properties and that the diffusion coefficients of its oxidation and reduction reactions are roughly the same.

[0058] Weigh 0.4 mmol of the prepared target product C and dissolve it in 8 ml of 1 mol / L KCl solution, shake and stir, and prepare a 50 mmol / L KCl solution after it forms a uniform solution; weigh 12 mmol zinc chloride and dissolve it in 12 mL of 1 mol / L ammonium chloride solution to prepare a 1 mol / L zinc chloride solution as the negative electrode material electrolyte. The above-mentioned positive electrode material electrolyte and negative electrode material electrolyte are stored in the positive and negative electrode storage tanks respectively and circulated with a peristaltic pump. The positive and negative electrode material electrolytes circulate through the pipelines and intersect on both sides of the diaphragm. The graphite felt or carbon paper electrodes on both sides of the diaphragm undergo redox reactions. The positive and negative electrodes are connected to the power load, the circuit transfers electrons, and the diaphragm transfers positive and negative ions to form a loop. The charge and discharge performance and cycle stability of the battery are evaluated, and constant current and constant voltage charge and discharge tests are performed using a current density of 24 mA / cm2, a cut-off current density of 2 mA / cm2, and a voltage of 2.2 V and 0.8 V, respectively. It can be seen that the battery charge and discharge curve shows a normal charging and discharging platform, and the first coulomb efficiency is above 99%. Fig.19 As shown. Within 100 consecutive cycles, the capacity decay rate is only 0.01% / cycle, and the Coulomb efficiency is maintained at an average of more than 99.5%, with good cycle performance. Fig. 20 shown.

[0059] Example 2 Step 1, dissolve ferrocenecarboxylic acid (20 mmol) in 20 mL of dichloromethane and pour into a 100 mL round-bottom flask. Dissolve phosgene (40 mmol) in 40 mL of dichloromethane and slowly titrate into the round-bottom flask with a constant pressure funnel to react with ferrocenecarboxylic acid. During this process, the hydroxyl group in the carboxyl group of ferrocenecarboxylic acid is exchanged with the chlorine group in phosgene. Then, the reaction system is placed in an oxygen-free state by three vacuum-filling-nitrogen operations, stirred in a water bath, and reacted at room temperature for 1.5 h. After the reaction is completed, dichloromethane is removed by rotary evaporation, and n-pentane is added to reduce the solubility of the product in the solvent. The product is precipitated as a solid, the solution is collected, and n-pentane is removed by rotary evaporation. If a brown-red liquid is obtained, step 2 is quickly performed.

[0060] Step 2, add the product ferrocenecarbonyl chloride (20 mmol) obtained in step 1 to a 100 mL round-bottom flask in sequence. Dissolve dimethylethylenediamine (30 mmol) in 50 mL of dichloromethane and slowly titrate it into the round-bottom flask with a constant pressure funnel to react with ferrocenecarbonyl chloride. During this process, the acyl chloride group of ferrocenecarbonyl chloride reacts with the amine group in dimethylethylenediamine to form an amide bond. Then, the reaction system is placed in an oxygen-free state by three vacuum-filling nitrogen operations, stirring in an ice-water bath, and maintaining the reaction at 0°C for 2 h. After the reaction is completed, deionized water (30 mL) is added to extract and remove excess dichloromethane, collect the organic phase, rotary evaporate and wash with deionized water (30 mL) to obtain a brown-red solid D, as shown in the following formula, and proceed to step 3.

[0061]

[0062] Reactive,

[0063] Step 3, the brown-red solid D (20 mmol) obtained in step 2 was dissolved in 20 mL of acetone and poured into a 100 mL round-bottom flask. The reaction system was placed in an oxygen-free state by three vacuum-filling and nitrogen-filling operations. 3 mL of iodomethane was added dropwise under stirring in a water bath, and the mixture was reacted at 25°C for 12 h. After the reaction was completed, the organic phase was extracted with deionized water (30 mL), and the brown-red solid E was obtained by rotary evaporation.

[0064]

[0065] The reaction formula is

[0066] Step 4, the brown-red solid product E obtained in step 3 is dissolved in deionized water, ion exchange is performed through a resin, and the product is washed by rotary evaporation to obtain the target product F, with a yield of 90%. Its H NMR spectrum is shown in the attached Figure 2 shown.

[0067]

[0068] The reaction formula is:

[0069] Weigh 0.016 mmol of the prepared target product F and dissolve it in 8 ml of 1 mol / L KCl solution, shake and stir, and after it forms a uniform solution, prepare it into 2 mmol / L KCl solution. The electrolyte prepared above is subjected to cyclic voltammetry scanning test using a three-electrode system, wherein Ag / AgCl is the reference electrode, the Pt electrode is the counter electrode, and the glassy carbon electrode is the working electrode. The scanning rates are 25 mV / s, 64 mV / s, 100 mV / s, 225 mV / s, 400 mV / s and 625 mV / s. And the redox peak potential is fitted with the square root of the scanning rate, and the slope is on the same order of magnitude. At the same time, its redox potential, redox potential difference, and redox current basically do not change with the change of the square root of the scanning rate, as shown in the attached figure. Figure 5 , Figure 8 , Fig.11 , Fig.14 , Fig.17 This proves that the molecule has reversible electrochemical properties and that the diffusion coefficients of its oxidation and reduction reactions are roughly the same.

[0070] Example 3 Step 1, dissolve ferrocenecarboxylic acid (20 mmol) in 20 mL of dichloromethane and pour into a 100 mL round-bottom flask. Dissolve phosgene (40 mmol) in 40 mL of dichloromethane and slowly titrate into the round-bottom flask with a constant pressure funnel to react with ferrocenecarboxylic acid. During this process, the hydroxyl group in the carboxyl group of ferrocenecarboxylic acid is exchanged with the chlorine group in phosgene. Then, the reaction system is placed in an oxygen-free state by three vacuum-filling-nitrogen operations, stirred in a water bath, and reacted at room temperature for 1.5 h. After the reaction is completed, dichloromethane is removed by rotary evaporation, and n-pentane is added to reduce the solubility of the product in the solvent. The product is precipitated as a solid, the solution is collected, and n-pentane is removed by rotary evaporation. If a brown-red liquid is obtained, step 2 is quickly performed.

[0071] Step 2, add the product ferrocenecarbonyl chloride (20 mmol) obtained in step 1 to a 250 mL round-bottom flask in sequence, and then add 50 mL of dichloromethane solvent. Then, continuously introduce ammonia into the system, stir in an ice-water bath, and keep the reaction at 0°C for 2 h. After the reaction is completed, continue to add dimethylamine (20 mmol) and formaldehyde (20 mmol) into the system, and then add 40 mL of water and ethanol mixed solvent (volume ratio of 1:1), introduce nitrogen into the obtained mixed system, and stir at room temperature for 2 h. After the reaction is completed, extract with deionized water (30 mL) to remove excess dichloromethane, collect the organic phase, rotary evaporate and wash with deionized water (30 mL), and proceed to step 3 if a brown solid is obtained.

[0072]

[0073] Step 3, dissolve the product obtained in step 2 (20 mmol) in 20 mL acetone and pour into a 100 mL round-bottom flask. Vacuum and fill with nitrogen three times to make the reaction system oxygen-free, add 3 mL iodomethane dropwise under stirring in a water bath, and react at 25°C for 12 hours after addition. After the reaction is completed, extract the organic phase with deionized water (30 mL), and rotary evaporate to obtain an orange-yellow solid.

[0074] The reaction formula is:

[0075] The product structure is:

[0076] Step 4, dissolve the orange-yellow solid product of step 3 in deionized water, perform ion exchange through resin, and wash the product by rotary evaporation to obtain the brown target product with a yield of 90%. Its H NMR spectrum is shown in the attached Figure 3 shown.

[0077]

[0078] The reaction of this step is as follows:

[0079] Weigh 0.016 mmol of the prepared target product and dissolve it in 8 ml of 1 mol / L KCl solution, shake and stir, and after it forms a uniform solution, prepare it into 2 mmol / L KCl solution. The electrolyte prepared above is subjected to cyclic voltammetry scanning test using a three-electrode system, in which Ag / AgCl is the reference electrode, the Pt electrode is the counter electrode, and the glassy carbon electrode is the working electrode. The scanning rates are 25 mV / s, 64 mV / s, 100 mV / s, 225 mV / s, 400 mV / s and 625 mV / s. And the redox peak potential is fitted with the square root of the scanning rate, and the slope is on the same order of magnitude. At the same time, its redox potential, redox potential difference, and redox current basically do not change with the change of the square root of the scanning rate, as shown in the attached figure. Figure 6 , Fig. 9 , Fig.12 , Fig.15 , Fig.18 This proves that the molecule has reversible electrochemical properties and that the diffusion coefficients of its oxidation and reduction reactions are roughly the same.

[0080] Analysis of the test results of Example 1-Example 3 shows that all three molecules have good reversible redox reaction capabilities, and the diffusion coefficient remains relatively stable with the square root change of the sweep rate. In addition, the cyclic voltammetry curve data of Comparative Example 1-Example 3 show that the effect of the length of the carbon chain on the ferrocene derivative is no longer obvious. Preliminary analysis shows that the introduction of the amide bond effectively regulates the charge effect of the ferrocene electrolyte molecule and weakens the effect of the carbon chain length on the redox potential of the ferrocene electrolyte molecule. Among them, the target product in Example 1 shows good stability in the charge and discharge performance and cycle test of the battery, confirming the strengthening effect of the introduction of the amide bond.

[0081] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An amidated ferrocene derivative, characterized in that: The structural formula is as follows: Where p=1, 2 or 3.

2. A method for preparing the amidated ferrocene derivative according to claim 1, characterized in that: The following steps are involved: Step 1, obtaining ferrocenecarbonyl chloride by reacting ferrocenecarboxylic acid and phosgene; Step 2, mixing the carbon chain reactant and ferrocenecarbonyl chloride in dichloromethane, and obtaining a first process solid after the reaction, wherein the structural formula of the first process solid is: Where p = 1, 2 or 3; Step 3, reacting the first process solid with methyl iodide to obtain a second process solid, wherein the structural formula of the second process solid is: Where p = 1, 2 or 3; Step 4, dissolving the solid from the second process in water, exchanging with a resin, and rotary evaporating to obtain the amidated ferrocene derivative chloride.

3. The method for preparing an amidated ferrocene derivative according to claim 2, characterized in that: In step 1, ferrocenecarboxylic acid and phosgene are dissolved in dichloromethane respectively for reaction, and the molar ratio of ferrocenecarboxylic acid to phosgene is 1:

2.

4. The method for preparing an amidated ferrocene derivative according to claim 2, characterized in that: In step 1, the reaction temperature is room temperature and the reaction time is 1.5 to 2 h.

5. The method for preparing an amidated ferrocene derivative according to claim 2, characterized in that: In step 2, the molar ratio of the carbon chain reactant to ferrocenecarbonyl chloride is (3-4):

2.

6. The method for preparing an amidated ferrocene derivative according to claim 2, characterized in that: In step 2, during the reaction of the carbon chain reactant and ferrocenecarbonyl chloride, the temperature of the reaction system is 0°C or room temperature, and the reaction time is 1 to 2 h.

7. The method for preparing an amidated ferrocene derivative according to claim 2, characterized in that: In step 2, when the reaction product p is 2 or 3, the carbon chain reactant is an amine reactant, and the amine reactant is dimethylpropylenediamine or dimethylethylenediamine. The specific reaction process is: The amine reactant is dissolved in dichloromethane to form a mixed solution of the amine reactant and dichloromethane, the mixed solution is mixed with ferrocenecarbonyl chloride, an acyl chloride reaction occurs, and a reaction system is obtained. The reaction system is repeatedly vacuumed and filled with nitrogen for several times, and the reaction system is reacted at 0°C. After the reaction is completed, the dichloromethane is removed to obtain a first solid product.

8. The method for preparing an amidated ferrocene derivative according to claim 2, characterized in that: In step 2, when the reaction product p is 1, the carbon chain reactant is a mixture of dimethylamine and formaldehyde, and the specific reaction process is: Ferrocenecarbonyl chloride and dichloromethane are mixed, ammonia is introduced, dimethylamine and formaldehyde are added, and then water and ethanol are added. Nitrogen is introduced and the mixture is stirred at room temperature for reaction. After the reaction is completed, dichloromethane is removed to obtain a first solid product.

9. The method for preparing an amidated ferrocene derivative according to claim 8, characterized in that: The mixing molar ratio of dimethylamine and formaldehyde is 1:

1.

10. An application of an amidated ferrocene derivative, characterized in that: The invention is used for preparing a cathode electrolyte in an aqueous liquid flow battery, wherein the concentration of the amidated ferrocene derivative in the cathode electrolyte is 0.05-3 mol / L.

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