A production process method for synthesizing ferrocene based on one-pot method

Abstract

The present application relates to the technical fields of organic metal compound synthesis, and discloses a production process method for synthesizing ferrocene based on one-pot method, which takes sodium, anhydrous ferrous chloride and dicyclopentadiene as raw materials, and completes the whole process of dicyclopentadiene depolymerization, sodium cyclopentadiene generation and ferrocene coordination synthesis in a non-protic solvent through gradient temperature control in one-pot method.The present application discards the disadvantages of multi-step reaction in traditional process, and does not need to prepare cyclopentadiene by pre-depolymerizing dicyclopentadiene, thus greatly simplifying the production process, reducing energy consumption and raw material loss, and achieving the product conversion rate of up to 85%, the purity of up to 99%, simple and controllable operation, adaptation to industrialized continuous production, and good economic and environmental benefits.

Description

Technical Field

[0001] This invention relates to the field of organometallic compound synthesis technology, specifically to a production process for synthesizing ferrocene using a one-pot method. Background Technology

[0002] Ferrocene, chemically known as dicyclopentadienyl iron with the molecular formula (C5H5)2Fe, is a transition metal organometallic compound with a typical sandwich structure. Its molecular structure consists of two cyclopentadienyl anions and one divalent iron cation linked by coordinate bonds, exhibiting excellent chemical stability, aromaticity, redox properties, and electrochemical characteristics. Since its initial discovery by Pauson et al. in 1951, ferrocene has not only advanced the theoretical development of transition metal organometallic chemistry, but its derivatives have also found widespread applications in numerous industrial fields: including as a gasoline antiknock agent to replace toxic tetraethyl lead, as a combustion rate catalyst for aerospace solid propellants, as a chiral catalyst and synthetic intermediate in organic synthesis, and demonstrating enormous application potential in emerging fields such as electronic materials, biomedical materials, and sensors.

[0003] With the continuous expansion of downstream applications of ferrocene and the steady growth of market demand, developing efficient, economical, environmentally friendly, and easily scalable ferrocene synthesis processes has become a core research direction in this field. Since Kealey TJ et al. prepared ferrocene by reacting cyclopentadiene magnesium bromide with anhydrous ferric chloride in 1951, researchers at home and abroad have successively developed a variety of chemical synthesis routes for ferrocene. The mainstream methods include the sodium metal method, the sodium cyclopentadiene method, the sodium methoxide method, the diethylamine method, the phase transfer catalysis method, and the dimethyl sulfoxide method.

[0004] The sodium cyclopentadiene method is a classic laboratory method for the synthesis of ferrocene. Its core principle is as follows: first, dicyclopentadiene is depolymerized to prepare cyclopentadiene; then, cyclopentadiene reacts with metallic sodium to generate sodium cyclopentadiene; finally, sodium cyclopentadiene reacts with anhydrous ferrous chloride in organic solvents such as tetrahydrofuran to produce ferrocene. This method has mild reaction conditions, but it has significant industrialization drawbacks: firstly, cyclopentadiene readily undergoes self-polymerization at room temperature, requiring immediate preparation and use, necessitating a separate high-temperature depolymerization process for dicyclopentadiene, resulting in a long process flow, large equipment investment, and high raw material loss; secondly, the reaction needs to be carried out in multiple steps, each requiring individual control, making operation cumbersome and demanding on production equipment and operational management, making continuous large-scale production difficult.

[0005] The diethylamine method uses cyclopentadiene, diethylamine, and anhydrous ferrous chloride as raw materials to directly synthesize ferrocene in an organic solvent. This method simplifies the process and reduces raw material costs to some extent, but it still has insurmountable drawbacks: the reaction requires a large amount of organic amine, the production environment is harsh, the recovery of organic amine is difficult and costly, and it easily causes environmental pollution; at the same time, the reaction cycle is long, and the purity of the product fluctuates greatly, making it difficult to meet the purity requirements of ferrocene in high-end applications.

[0006] Phase transfer catalysis is a novel synthetic route developed in recent years. It typically involves a two-phase system consisting of an alkaline aqueous solution and an organic solvent, using a quaternary ammonium salt as a phase transfer catalyst to transfer cyclopentadiene anions generated in the aqueous phase to the organic phase, where they undergo a coordination reaction with ferrous ions to form ferrocene. While this method offers low raw material costs, its industrial application is significantly limited: reaction efficiency is highly dependent on the activity and stability of the phase transfer catalyst, which is prone to deactivation and exhibits poor batch-to-batch stability; the reaction system generates large amounts of saline wastewater, resulting in high environmental treatment costs and failing to meet the requirements of green chemical development; furthermore, the reaction system is complex, requiring precise control of process parameters, and the product separation and purification steps are cumbersome, making it difficult to adapt to large-scale continuous production.

[0007] In addition to the above, other synthetic routes such as the sodium methoxide method and the dimethyl sulfoxide method also suffer from problems such as high raw material costs, harsh reaction conditions, low product yields, and difficulties in solvent recovery, which cannot meet the needs of large-scale industrial production. Therefore, there is an urgent need in this field to develop a ferrocene synthesis process that is short in process flow, simple in operation, low in energy consumption, high in product yield and purity, environmentally friendly, and easy to scale up industrially. Summary of the Invention

[0008] To overcome the shortcomings of the prior art, the present invention aims to provide a one-pot synthesis process for ferrocene. This process directly uses dicyclopentadiene as the starting material, without the need for pre-depolymerization to prepare cyclopentadiene. Through gradient temperature control, the entire process of dicyclopentadiene depolymerization, cyclopentadienyl sodium generation, and ferrocene coordination synthesis is completed in a single reaction system in one pot. This significantly simplifies the production process, reduces energy consumption and production costs, while ensuring high product yield and high purity, making it suitable for large-scale industrial production.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a production process for one-pot synthesis of ferrocene, using metallic sodium, anhydrous ferrous chloride, and dicyclopentadiene as raw materials, and synthesizing ferrocene in a one-pot process by gradient temperature control in an aprotic solvent; The molar ratio of sodium metal, dicyclopentadiene, and anhydrous ferrous chloride is (0.6~0.9):1:(0.5~1); The gradient temperature controlled one-pot reaction is as follows: First, all raw materials and aprotic solvent are added to the reactor at once, the temperature is raised to 180~200℃, and the reaction is maintained at this temperature for 1~2 hours. The stirring speed is controlled at 100~300 r / min to complete the depolymerization of dicyclopentadiene and the formation of cyclopentadienyl sodium. Then, the system temperature is adjusted to 100~200℃, and the reaction is maintained at this temperature for 2~4 hours. The stirring speed is controlled at 300~400 r / min to complete the coordination synthesis of ferrocene. The total reaction time is 1~6 hours.

[0010] Furthermore, the molar concentration of the dicyclopentadiene in the aprotic solvent is 5~15 mol / L.

[0011] Furthermore, the aprotic solvent is any one of diethylene glycol dimethyl ether, dimethyl sulfoxide, N,N-dimethylformamide, acetonitrile, and tetrahydrofuran.

[0012] Furthermore, after the reaction is completed, the reaction solution is subjected to solid-liquid separation to remove the byproduct sodium chloride. The resulting filtrate is washed with water to remove soluble impurities, recrystallized and purified, and then vacuum dried to obtain the ferrocene product.

[0013] The overall equation for the synthesis reaction of this invention is as follows: C 10 H 12 +2Na+FeCl2→(C5H5)2Fe+2NaCl+H2↑ Among them, C 10 H 12 It is dicyclopentadiene, and (C5H5)2Fe is ferrocene.

[0014] The reaction mechanism of this invention is as follows: First, under high temperature conditions of 180-200℃, dicyclopentadiene undergoes a depolymerization reaction to generate two molecules of cyclopentadiene; simultaneously, cyclopentadiene undergoes a displacement reaction with metallic sodium to generate cyclopentadienyl sodium and hydrogen gas; after the above depolymerization and salt formation reactions are completed, the system temperature is adjusted, and cyclopentadienyl sodium undergoes a coordination reaction with anhydrous ferrous chloride in an aprotic solvent to generate ferrocene with a sandwich structure, with sodium chloride as a byproduct. This invention, through the synergistic control of gradient temperature and stirring speed, enables the above three-step reactions to proceed sequentially and efficiently in the same reactor, eliminating the need for intermediate separation and purification steps, thus achieving a true one-pot synthesis.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: This invention eliminates the multi-step process required by traditional methods, which necessitates the pre-depolymerization of dicyclopentadiene to prepare cyclopentadiene and the stepwise synthesis of cyclopentadienyl sodium and ferrocene. Instead, it directly uses dicyclopentadiene as the starting material and completes the entire reaction process in a single reactor through gradient temperature control, achieving true one-pot synthesis. This significantly reduces equipment investment and process turnaround time, and the operation is simple, controllable, and easily achievable for continuous industrial production.

[0016] This invention eliminates the need for a separate high-temperature depolymerization device for dicyclopentadiene and a storage device for cyclopentadiene, thus avoiding self-polymerization losses during the storage process of cyclopentadiene. It also reduces the energy consumption of repeated heating and cooling in multi-step reactions, and the solvent can be recycled through distillation, which significantly reduces production energy consumption and raw material costs.

[0017] This invention optimizes the raw material ratio, reaction temperature, reaction time, and stirring parameters to achieve efficient and coordinated reaction of each step. The product conversion rate can reach up to 85%, and the purity can reach up to 99%, which can meet the purity requirements of ferrocene in different application fields, especially high-end fields. At the same time, the one-pot process reduces batch fluctuations caused by human operation and process turnover, resulting in excellent product quality stability.

[0018] The reaction system of this invention is a homogeneous organic system, which generates no wastewater and produces only solid sodium chloride as a byproduct. Solid waste treatment is simple, and the organic solvent can be recycled. Compared with traditional phase transfer catalysis and other processes, it significantly reduces the cost of treating waste and meets the requirements of green chemical development. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] All raw materials used in the embodiments of this invention are commercially available industrial-grade products, wherein the purity of dicyclopentadiene is ≥98%, the purity of metallic sodium is ≥99.5%, the purity of anhydrous ferrous chloride is ≥99%, and the aprotic solvents used are all anhydrous reagents with a water content ≤50ppm.

[0021] Example 1 This embodiment provides a one-pot synthesis process for ferrocene, with the following specific steps: Sodium metal, dicyclopentadiene, and anhydrous ferrous chloride are weighed according to a molar ratio of sodium metal:dicyclopentadiene:anhydrous ferrous chloride of 0.6:1:0.5 and added to a high-pressure reactor. Diethylene glycol dimethyl ether is added as an aprotic solvent, and the molar concentration of dicyclopentadiene is controlled at 10 mol / L. The reactor is sealed, stirring is started, and the stirring speed is controlled at 200 r / min. The temperature is raised to 200℃ and maintained for 1 hour to complete the depolymerization of dicyclopentadiene and the formation of cyclopentadienyl sodium. Subsequently, the system temperature is adjusted to 100℃, the stirring speed is increased to 400 r / min, and the reaction is maintained for 3 hours to complete the synthesis of ferrocene. The total reaction time is 4 hours. After the reaction was completed, the reaction solution was cooled to room temperature, and the byproduct sodium chloride solid was removed by vacuum filtration. The filtrate was washed three times with deionized water. The organic phase was subjected to vacuum distillation to remove some of the solvent, and then cooled and recrystallized. The filtered solid was dried under vacuum to obtain the ferrocene product. The conversion rate of dicyclopentadiene was 83%, and the purity of the ferrocene product was 96%.

[0022] Example 2 This embodiment provides a one-pot synthesis process for ferrocene, with the following specific steps: Sodium metal, dicyclopentadiene, and anhydrous ferrous chloride are weighed and added to a high-pressure reactor according to a molar ratio of sodium metal:dicyclopentadiene:anhydrous ferrous chloride of 0.8:1:0.7. Diethylene glycol dimethyl ether is added as an aprotic solvent, and the molar concentration of dicyclopentadiene is controlled at 10 mol / L. The reactor is sealed, stirring is started, and the stirring speed is controlled at 200 r / min. The temperature is raised to 200℃ and maintained for 1 hour to complete the depolymerization of dicyclopentadiene and the formation of cyclopentadienyl sodium. Subsequently, the system temperature is adjusted to 100℃, the stirring speed is increased to 400 r / min, and the reaction is maintained for 3 hours to complete the synthesis of ferrocene. The total reaction time is 4 hours. After the reaction, the ferrocene product is obtained using the same post-processing method as in Example 1. Testing shows that the conversion rate of dicyclopentadiene is 81%, and the purity of the ferrocene product is 95.6%.

[0023] Example 3 This embodiment provides a one-pot synthesis process for ferrocene, with the following specific steps: Sodium metal, dicyclopentadiene, and anhydrous ferrous chloride are weighed and added to a high-pressure reactor according to a molar ratio of sodium metal:dicyclopentadiene:anhydrous ferrous chloride of 0.6:1:0.5. Diethylene glycol dimethyl ether is added as an aprotic solvent, and the molar concentration of dicyclopentadiene is controlled at 10 mol / L. The reactor is sealed, stirring is started, and the stirring speed is controlled at 200 r / min. The temperature is raised to 200℃ and maintained for 1 hour to complete the depolymerization of dicyclopentadiene and the formation of cyclopentadienyl sodium. Subsequently, the system temperature is adjusted to 150℃, the stirring speed is increased to 400 r / min, and the reaction is maintained for 3 hours to complete the synthesis of ferrocene. The total reaction time is 4 hours. After the reaction, the ferrocene product is obtained using the same post-processing method as in Example 1. Testing shows that the conversion rate of dicyclopentadiene is 85%, and the purity of the ferrocene product is 96%.

[0024] Example 4 This embodiment provides a one-pot synthesis process for ferrocene, with the following specific steps: Sodium metal, dicyclopentadiene, and anhydrous ferrous chloride are weighed and added to a high-pressure reactor according to a molar ratio of sodium metal:dicyclopentadiene:anhydrous ferrous chloride of 0.6:1:0.5. Diethylene glycol dimethyl ether is added as an aprotic solvent, and the molar concentration of dicyclopentadiene is controlled at 10 mol / L. The reactor is sealed, stirring is started, and the stirring speed is controlled at 200 r / min. The temperature is raised to 200℃ and maintained for 2 hours to complete the depolymerization of dicyclopentadiene and the formation of cyclopentadienyl sodium. Subsequently, the system temperature is adjusted to 150℃, the stirring speed is increased to 400 r / min, and the reaction is maintained for 3 hours to complete the synthesis of ferrocene. The total reaction time is 5 hours. After the reaction, the ferrocene product is obtained using the same post-processing method as in Example 1. Testing shows that the conversion rate of dicyclopentadiene is 81%, and the purity of the ferrocene product is 95%.

[0025] Example 5 This embodiment provides a one-pot synthesis process for ferrocene, with the following specific steps: Sodium metal, dicyclopentadiene, and anhydrous ferrous chloride are weighed and added to a high-pressure reactor according to a molar ratio of sodium metal:dicyclopentadiene:anhydrous ferrous chloride of 0.6:1:0.5. Dimethyl sulfoxide is added as an aprotic solvent, and the molar concentration of dicyclopentadiene is controlled at 10 mol / L. The reactor is sealed, stirring is started, and the stirring speed is controlled at 200 r / min. The temperature is raised to 200℃ and maintained for 1 hour to complete the depolymerization of dicyclopentadiene and the formation of cyclopentadienyl sodium. Subsequently, the system temperature is adjusted to 100℃, the stirring speed is increased to 400 r / min, and the reaction is maintained for 3 hours to complete the synthesis of ferrocene. The total reaction time is 4 hours. After the reaction, the ferrocene product is obtained using the same post-processing method as in Example 1. Testing shows that the conversion rate of dicyclopentadiene is 78%, and the purity of the ferrocene product is 96%.

[0026] Example 6 This embodiment provides a one-pot synthesis process for ferrocene, with the following specific steps: Sodium metal, dicyclopentadiene, and anhydrous ferrous chloride are weighed and added to a high-pressure reactor according to a molar ratio of sodium metal:dicyclopentadiene:anhydrous ferrous chloride of 0.6:1:0.5. Dimethyl sulfoxide is added as an aprotic solvent, and the molar concentration of dicyclopentadiene is controlled at 10 mol / L. The reactor is sealed, stirring is started, and the stirring speed is controlled at 200 r / min. The temperature is raised to 200℃ and maintained for 2 hours to complete the depolymerization of dicyclopentadiene and the formation of cyclopentadienyl sodium. Subsequently, the system temperature is adjusted to 160℃, the stirring speed is increased to 400 r / min, and the reaction is maintained for 3 hours to complete the synthesis of ferrocene. The total reaction time is 5 hours. After the reaction, the ferrocene product is obtained using the same post-processing method as in Example 1. Testing shows that the conversion rate of dicyclopentadiene is 80%, and the purity of the ferrocene product is 97%.

[0027] Example 7

[0028] This embodiment provides a one-pot synthesis process for ferrocene, with the following specific steps: Sodium metal, dicyclopentadiene, and anhydrous ferrous chloride are weighed and added to a high-pressure reactor according to a molar ratio of sodium metal:dicyclopentadiene:anhydrous ferrous chloride of 0.6:1:0.5. N,N-dimethylformamide is added as an aprotic solvent, and the molar concentration of dicyclopentadiene is controlled at 10 mol / L. The reactor is sealed, stirring is started, and the stirring speed is controlled at 200 r / min. The temperature is raised to 200℃ and maintained for 1 hour to complete the depolymerization of dicyclopentadiene and the formation of cyclopentadienyl sodium. Subsequently, the system temperature is adjusted to 150℃, the stirring speed is increased to 400 r / min, and the reaction is maintained for 3 hours to complete the synthesis of ferrocene. The total reaction time is 4 hours. After the reaction, the ferrocene product is obtained using the same post-processing method as in Example 1. Testing shows that the conversion rate of dicyclopentadiene is 75%, and the purity of the ferrocene product is 97%.

[0029] Example 8 This embodiment provides a one-pot synthesis process for ferrocene, with the following specific steps: Sodium metal, dicyclopentadiene, and anhydrous ferrous chloride are weighed and added to a high-pressure reactor according to a molar ratio of sodium metal:dicyclopentadiene:anhydrous ferrous chloride of 0.6:1:0.5. N,N-dimethylformamide is added as an aprotic solvent, and the molar concentration of dicyclopentadiene is controlled at 10 mol / L. The reactor is sealed, stirring is started, and the stirring speed is controlled at 200 r / min. The temperature is raised to 200℃ and maintained for 2 hours to complete the depolymerization of dicyclopentadiene and the formation of cyclopentadienyl sodium. Subsequently, the system temperature is adjusted to 150℃, the stirring speed is increased to 400 r / min, and the reaction is maintained for 3 hours to complete the synthesis of ferrocene. The total reaction time is 5 hours. After the reaction, the ferrocene product is obtained using the same post-processing method as in Example 1. Testing shows that the conversion rate of dicyclopentadiene is 78%, and the purity of the ferrocene product is 97%.

[0030] Example 9 This embodiment provides a one-pot synthesis process for ferrocene, with the following specific steps: Sodium metal, dicyclopentadiene, and anhydrous ferrous chloride are weighed and added to a high-pressure reactor according to a molar ratio of sodium metal:dicyclopentadiene:anhydrous ferrous chloride of 0.6:1:0.5. Acetonitrile is added as an aprotic solvent, and the molar concentration of dicyclopentadiene is controlled at 10 mol / L. The reactor is sealed, stirring is started, and the stirring speed is controlled at 200 r / min. The temperature is raised to 200℃ and maintained for 1 hour to complete the depolymerization of dicyclopentadiene and the formation of cyclopentadienyl sodium. Subsequently, the system temperature is adjusted to 100℃, the stirring speed is increased to 400 r / min, and the reaction is maintained for 3 hours to complete the synthesis of ferrocene. The total reaction time is 4 hours. After the reaction, the ferrocene product is obtained using the same post-processing method as in Example 1. Testing shows that the conversion rate of dicyclopentadiene is 70%, and the purity of the ferrocene product is 95%.

[0031] Example 10 This embodiment provides a one-pot synthesis process for ferrocene, with the following specific steps: Sodium metal, dicyclopentadiene, and anhydrous ferrous chloride are weighed according to a molar ratio of sodium metal:dicyclopentadiene:anhydrous ferrous chloride of 0.6:1:0.5 and added to a high-pressure reactor. Tetrahydrofuran is added as an aprotic solvent, and the molar concentration of dicyclopentadiene is controlled at 10 mol / L. The reactor is sealed, stirring is started, and the stirring speed is controlled at 200 r / min. The temperature is raised to 200℃ and maintained for 1 hour to complete the depolymerization of dicyclopentadiene and the formation of cyclopentadienyl sodium. Subsequently, the system temperature is adjusted to 150℃, the stirring speed is increased to 400 r / min, and the reaction is maintained for 3 hours to complete the synthesis of ferrocene. The total reaction time is 4 hours. After the reaction, the reaction solution is cooled to room temperature, and the byproduct sodium chloride is removed by vacuum filtration. The filtrate is then subjected to reduced pressure distillation to remove some solvent, cooled, and recrystallized. The filtered solid is then vacuum dried to obtain the ferrocene product. Tests showed that the conversion rate of dicyclopentadiene was 70%, and the purity of the ferrocene product was 97%.

[0032] Example 11 This embodiment provides a one-pot synthesis process for ferrocene, with the following specific steps: Sodium metal, dicyclopentadiene, and anhydrous ferrous chloride are weighed and added to a high-pressure reactor according to a molar ratio of sodium metal:dicyclopentadiene:anhydrous ferrous chloride of 0.6:1:1. Tetrahydrofuran is added as an aprotic solvent, and the molar concentration of dicyclopentadiene is controlled at 10 mol / L. The reactor is sealed, stirring is started, and the stirring speed is controlled at 200 r / min. The temperature is raised to 200℃ and maintained for 1 hour to complete the depolymerization of dicyclopentadiene and the formation of cyclopentadienyl sodium. Subsequently, the system temperature is adjusted to 150℃, the stirring speed is increased to 400 r / min, and the reaction is maintained for 3 hours to complete the synthesis of ferrocene. The total reaction time is 4 hours. After the reaction, the ferrocene product is obtained using the same post-processing method as in Example 10. Testing shows that the conversion rate of dicyclopentadiene is 68%, and the purity of the ferrocene product is 99%.

[0033] Example 12 This embodiment provides a one-pot synthesis process for ferrocene, with the following specific steps: Sodium metal, dicyclopentadiene, and anhydrous ferrous chloride are weighed and added to a high-pressure reactor according to a molar ratio of sodium metal:dicyclopentadiene:anhydrous ferrous chloride of 0.6:1:1. Tetrahydrofuran is added as an aprotic solvent, and the molar concentration of dicyclopentadiene is controlled at 10 mol / L. The reactor is sealed, stirring is started, and the stirring speed is controlled at 200 r / min. The temperature is raised to 200℃ and maintained for 1 hour to complete the depolymerization of dicyclopentadiene and the formation of cyclopentadienyl sodium. Subsequently, the system temperature is adjusted to 150℃, the stirring speed is increased to 400 r / min, and the reaction is maintained for 6 hours to complete the synthesis of ferrocene. The total reaction time is 7 hours. After the reaction, the ferrocene product is obtained using the same post-processing method as in Example 10. Testing shows that the conversion rate of dicyclopentadiene is 67%, and the purity of the ferrocene product is 98%.

[0034] Example 13 This embodiment provides a one-pot synthesis process for ferrocene, with the following specific steps: Sodium metal, dicyclopentadiene, and anhydrous ferrous chloride are weighed and added to a high-pressure reactor according to a molar ratio of sodium metal:dicyclopentadiene:anhydrous ferrous chloride of 0.6:1:1. Tetrahydrofuran is added as an aprotic solvent, and the molar concentration of dicyclopentadiene is controlled at 10 mol / L. The reactor is sealed, stirring is started, and the stirring speed is controlled at 200 r / min. The temperature is raised to 200℃ and maintained for 1 hour to complete the depolymerization of dicyclopentadiene and the formation of cyclopentadienyl sodium. Subsequently, the system temperature is adjusted to 150℃, the stirring speed is increased to 400 r / min, and the reaction is maintained for 2 hours to complete the synthesis of ferrocene. The total reaction time is 3 hours. After the reaction, the ferrocene product is obtained using the same post-processing method as in Example 10. Testing shows that the conversion rate of dicyclopentadiene is 60%, and the purity of the ferrocene product is 99%.

[0035] Comparative Example 1 This comparative example uses the traditional sodium cyclopentadiene method to synthesize ferrocene in steps, as follows: Dicyclopentadiene depolymerization: Dicyclopentadiene is added to a distillation vessel and heated to 170°C for depolymerization distillation. The fraction at 40-42°C is collected to obtain cyclopentadiene, which is prepared and used immediately. Preparation of sodium cyclopentadienyl: Under nitrogen protection, metallic sodium was added to anhydrous tetrahydrofuran and stirred to disperse. Freshly prepared cyclopentadiene was slowly added dropwise under ice bath conditions. The molar ratio of metallic sodium to cyclopentadiene was 1:1. After the addition was completed, the mixture was stirred at room temperature for 4 hours to obtain a tetrahydrofuran solution of sodium cyclopentadienyl. Ferrocene synthesis: Under nitrogen protection, anhydrous ferrous chloride was added in batches to a sodium cyclopentadiene solution at a molar ratio of 2:1. The mixture was heated to 60°C and stirred for 6 hours to obtain a ferrocene reaction solution. After the reaction, the ferrocene product was obtained using the same post-treatment method as in Example 10. The total conversion rate of dicyclopentadiene was 62%, the purity of the ferrocene product was 94%, and the total production time was 18 hours.

[0036] Comparative Example 2 This comparative example uses a one-pot isothermal reaction to synthesize ferrocene without gradient temperature control. The specific steps are as follows: Sodium metal, dicyclopentadiene, and anhydrous ferrous chloride are weighed according to a molar ratio of 0.6:1:0.5 and added to a high-pressure reactor. Diethylene glycol dimethyl ether is added as an aprotic solvent, and the molar concentration of dicyclopentadiene is controlled at 10 mol / L. The reactor is sealed, stirring is started, and the speed is controlled at 400 r / min. The temperature is directly raised to 150℃ and maintained for 4 hours. After the reaction, the ferrocene product is obtained using the same post-processing method as in Example 1. Testing showed that the conversion rate of dicyclopentadiene was 42%, and the purity of the ferrocene product was 82%. The dicyclopentadiene depolymerization was incomplete, indicating an insufficient reaction.

[0037] Comparative Example 3 The raw material ratio in this comparative example exceeds the scope of this invention. The specific steps are as follows: Sodium metal, dicyclopentadiene, and anhydrous ferrous chloride were weighed according to a molar ratio of 0.5:1:0.4 (sodium metal:dicyclopentadiene:anhydrous ferrous chloride) and added to a high-pressure reactor. Diethylene glycol dimethyl ether was added as an aprotic solvent, and the molar concentration of dicyclopentadiene was controlled at 10 mol / L. The reactor was sealed, stirring was started, and the stirring speed was controlled at 200 r / min. The temperature was raised to 200°C and maintained for 1 hour. Subsequently, the system temperature was adjusted to 150°C, the stirring speed was increased to 400 r / min, and the reaction was maintained for 3 hours. After the reaction, the ferrocene product was obtained using the same post-processing method as in Example 1. Testing showed that the conversion rate of dicyclopentadiene was 51%, and the purity of the ferrocene product was 88%. Due to insufficient feeding of sodium metal and ferrous chloride, the conversion of cyclopentadiene was incomplete, resulting in a significant decrease in product yield and purity.

[0038] Comparative Example 4 The raw material ratio in this comparative example exceeds the scope of this invention. The specific steps are as follows: Sodium metal, dicyclopentadiene, and anhydrous ferrous chloride were weighed according to a molar ratio of sodium metal:dicyclopentadiene:anhydrous ferrous chloride of 1.0:1:1.2 and added to a high-pressure reactor. Diethylene glycol dimethyl ether was added as an aprotic solvent, and the molar concentration of dicyclopentadiene was controlled at 10 mol / L. The reactor was sealed, stirring was started, and the stirring speed was controlled at 200 r / min. The temperature was raised to 200°C and maintained for 1 hour. Subsequently, the system temperature was adjusted to 150°C, the stirring speed was increased to 400 r / min, and the reaction was maintained for 3 hours. After the reaction, the ferrocene product was obtained using the same post-processing method as in Example 1. Testing showed that the conversion rate of dicyclopentadiene was 76%, and the purity of the ferrocene product was 85%. Due to excessive addition of sodium metal and ferrous chloride, the impurity content in the product increased, the purity decreased significantly, and the raw material cost increased substantially.

[0039] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0040] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0041] Those skilled in the art should understand that the above descriptions are merely several specific embodiments of the present invention, and not all embodiments.

Claims

1. A production process for synthesizing ferrocene using a one-pot method, characterized in that, Includes the following steps: Ferrocene was synthesized in a one-pot process with gradient temperature control using metallic sodium, anhydrous ferrous chloride, and dicyclopentadiene as raw materials in an aprotic solvent. The molar ratio of sodium metal, dicyclopentadiene, and anhydrous ferrous chloride is (0.6~0.9):1:(0.5~1); The gradient temperature controlled one-pot reaction is as follows: First, all raw materials and aprotic solvent are added to the reactor at once, the temperature is raised to 180~200℃, and the reaction is maintained at this temperature for 1~2 hours. The stirring speed is controlled at 100~300 r / min to complete the depolymerization of dicyclopentadiene and the formation of cyclopentadienyl sodium. Then, the system temperature is adjusted to 100~200℃, and the reaction is maintained at this temperature for 2~4 hours. The stirring speed is controlled at 300~400 r / min to complete the coordination synthesis of ferrocene. The total reaction time is 1~6 hours.

2. The production process method for synthesizing ferrocene based on the one-pot method according to claim 1, characterized in that, The molar concentration of the dicyclopentadiene in the aprotic solvent is 5~15 mol / L.

3. The production process method for synthesizing ferrocene based on the one-pot method according to claim 1, characterized in that, The aprotic solvent is any one of diethylene glycol dimethyl ether, dimethyl sulfoxide, N,N-dimethylformamide, acetonitrile, and tetrahydrofuran.

4. The production process method for synthesizing ferrocene based on the one-pot method according to claim 1, characterized in that, The molar ratio of sodium metal, dicyclopentadiene, and anhydrous ferrous chloride is 0.6:1:0.

5.

5. The production process method for synthesizing ferrocene based on the one-pot method according to claim 1, characterized in that, The molar ratio of sodium metal, dicyclopentadiene, and anhydrous ferrous chloride is 0.8:1:0.

7.

6. The production process method for synthesizing ferrocene based on the one-pot method according to claim 1, characterized in that, The molar ratio of sodium metal, dicyclopentadiene, and anhydrous ferrous chloride is 0.6:1:

1.

7. The production process method for synthesizing ferrocene based on the one-pot method according to claim 1, characterized in that, The reaction temperature for the coordination synthesis stage is 100~160℃.

8. The production process method for synthesizing ferrocene based on the one-pot method according to claim 1, characterized in that, After the reaction is completed, the reaction solution is subjected to solid-liquid separation. The resulting filtrate is washed with water, recrystallized, and dried to obtain the ferrocene product.