Substituted cyclopentadiene as well as preparation method and application thereof

Abstract

The invention provides substituted cyclopentadiene as well as a preparation method and application thereof. The preparation method comprises the following steps: by taking tetrahydrofuran as a reaction solvent, mixing alkali metal cyclopentadiene with halogenated hydrocarbon, carrying out substitution reaction at low temperature in an inert gas atmosphere, so that metal atoms in the alkali metal cyclopentadiene are substituted by alkyl of the halogenated hydrocarbon, carrying out solid-liquid separation after the reaction is finished, adding a polymerization inhibitor into a liquid phase, and carrying out distillation purification, so as to obtain the cyclopentadiene. The substituted cyclopentadiene is prepared. According to the preparation method provided by the invention, by controlling the feeding sequence and the feeding rate, diene addition and polymerization reaction spontaneously carried out in product concentration and heating links are effectively avoided, and the yield is improved; according to the method, only tetrahydrofuran is used as a reaction medium, so that the cost is reduced, and the method is green and environment-friendly; the product can be purified only through distillation, so that the preparation steps are greatly simplified, and the method is easy to popularize.

Description

Technical Field

[0001] The invention belongs to the technical field of compound synthesis, and specifically relates to a substituted cyclopentadiene and a preparation method and application thereof. Background Art

[0002] Cyclopentadiene is an important C5 component raw material in the synthetic industry. Its chemical properties are active and can undergo various types of reactions. As a stable ligand, cyclopentadienyl can form a variety of stable metal complexes by coordinating with metal ions through ionic bonds or π bonds. According to the characteristics of different metal cyclopentadiene complexes, they can be used as metal precursors, catalysts, organic hydrogenation reagents, explosion-proof agents and many other chemical raw materials or preparations. By adjusting the substituent modification on cyclopentadiene, the properties of cyclopentadienyl metal complexes can be optimized, and cyclopentadiene with different substituents can be synthesized.

[0003] Chinese invention patent CN102844284A discloses a method for synthesizing a substituted cyclopentadiene compound, using a cyclopentadienyl Grignard reagent (CpMgX) and a halogenated alkane (RX) to react by heating in tetrahydrofuran, removing the solvent in vacuo after the reaction, extracting the product with pentane, filtering and separating and washing the solid phase, collecting and merging the liquid phase, and then removing pentane to obtain the corresponding product. This scheme requires the preparation of a cyclopentadienyl Grignard reagent in advance, and the reaction process requires heating, and the extraction process requires the use of other solvents, and the synthesis steps are complicated.

[0004] The document "Journal of the American Chemical Society 2018, 140(47), 16253-16263" discloses a method for continuously synthesizing substituted cyclopentadiene using cyclopentadiene, which specifically comprises: under low temperature conditions, adding 1.2 molar equivalents of n-butyl lithium hexane solution (n-BuLi in hexane) dropwise to a freshly prepared 1.1 molar equivalents of cyclopentadiene tetrahydrofuran solution (Cp in THF); after reacting for 1 hour, adding 1 molar equivalent of halogenated hydrocarbon dropwise to the reaction system, reacting at room temperature for 48-72 hours, and obtaining a substituted cyclopentadiene product after extraction, concentration and purification. After the reaction is completed, this solution needs to perform an extraction operation to remove the by-product salt and tetrahydrofuran, and obtain the product after purification. On the one hand, due to the reaction by-products, they need to be extracted, concentrated and purified, resulting in the need to use a large amount of organic solvents in the preparation process, and there are many reaction and post-treatment steps, resulting in relatively large product losses, resulting in a low yield of finished products; on the other hand, the reaction time itself is too long, resulting in a long production cycle, low production capacity and high energy consumption in the production process.

[0005] Therefore, there is an urgent need to provide a method for preparing substituted cyclopentadiene which is simple, efficient, high in yield and produces few by-products. Summary of the invention

[0006] The main purpose of the present invention is to provide a substituted cyclopentadiene and a preparation method and application thereof to overcome the deficiencies of the prior art.

[0007] In order to achieve the above technical objectives, the technical solution adopted by the present invention includes:

[0008] The invention provides a method for preparing substituted cyclopentadiene, which comprises: using tetrahydrofuran as a reaction solvent, mixing alkali metal cyclopentadiene and halogenated hydrocarbon, and carrying out a substitution reaction under an inert gas atmosphere at a temperature of -30°C to -20°C, wherein the metal atom in the alkali metal cyclopentadiene is replaced by the hydrocarbon group of the halogenated hydrocarbon to obtain the substituted cyclopentadiene.

[0009] Furthermore, the specific steps of the above preparation method include:

[0010] S1. Providing a mixture of anhydrous tetrahydrofuran and a halogenated hydrocarbon;

[0011] S2. providing an alkali metal cyclopentadienylfuran solution;

[0012] S3. Substitution reaction: in an inert gas atmosphere, the alkali metal cyclopentadiene furan solution is added dropwise to the mixture to form a mixed reaction system, and the substitution reaction is carried out under stirring at a temperature of -30°C to -20°C, wherein the metal atom in the alkali metal cyclopentadiene is replaced by the hydrocarbon group of the halogenated hydrocarbon to obtain a reaction product;

[0013] S4. Post-treatment: performing solid-liquid separation on the reaction product to obtain a liquid phase, adding a polymerization inhibitor to the liquid phase, and obtaining substituted cyclopentadiene after distillation.

[0014] Furthermore, the temperature of the mixture of anhydrous tetrahydrofuran and halogenated hydrocarbon in S1 is -30 to -20°C; the temperature of the dropwise addition of the alkali metal cyclopentadiene furan solution in S3 is -30 to -20°C; in S3, the dropwise addition speed of the alkali metal cyclopentadiene tetrahydrofuran solution is 50-100 mL / min.

[0015] Furthermore, the reaction time of the substitution reaction is 1 h to 4 h.

[0016] Furthermore, the molar ratio of the alkali metal cyclopentadiene to the halogenated hydrocarbon is 0.95 to 1:1.

[0017] Further, in S4, the substituted cyclopentadiene includes a mixture of a 1-substituted product and a 2-substituted product, and the molar ratio of the 1-substituted product to the 2-substituted product is 0.45:0.55-0.37:0.63.

[0018] Furthermore, the alkali metal cyclopentadiene furan solution comprises a mixture of cyclopentadiene containing sodium or potassium and furan.

[0019] Furthermore, the chemical formula of the halogenated hydrocarbon is RX, wherein R is a hydrocarbon group, including any one of n-propyl, isopropyl, and n-butyl; X is a halogen atom or OTs, and the halogen atom includes Br or I.

[0020] Furthermore, the polymerization inhibitor includes any one of hydroquinone, tert-butylcatechol, and 2-sec-butyl-4,6-dinitrophenol.

[0021] Furthermore, in S4, the post-treatment step includes solid-liquid separation and distillation purification; the solid-liquid separation includes continuing to stir the reaction product for 1h-2h after the reaction is completed, then restoring the temperature to 20°C-25°C and letting it stand, and performing solid-liquid separation after precipitation to obtain the liquid phase.

[0022] Furthermore, the distillation purification includes adding a polymerization inhibitor to the liquid phase and then distilling to obtain substituted cyclopentadiene.

[0023] Furthermore, the stirring speed during the solid-liquid separation is 80-150 rpm.

[0024] Furthermore, the distillation purification includes adding the polymerization inhibitor, stirring for 1 to 4 hours, and then distilling at a temperature of 20° C. to 25° C. and a pressure of 3 to 5 kPa.

[0025] Furthermore, the molar ratio of the polymerization inhibitor to the halogenated hydrocarbon is 0.002-0.005:1.

[0026] Furthermore, in the distillation purification, the receiving conditions of the distillation product include a vacuum degree of 0.5-1 kPa and a receiving temperature of -30 to -20°C.

[0027] The embodiments of the present invention also provide substituted cyclopentadiene prepared by the preparation method provided by the present invention, and the application of the substituted cyclopentadiene in the field of preparing metal precursors. The substituted cyclopentadiene is used as a reactant and coordinated with a corresponding metal salt or metal organic matter to form a corresponding metal precursor compound, such as di(n-propylcyclopentadienyl)magnesium or isopropylcyclopentadienyl hafnium trichloride. Since the cyclopentadienyl group is a stable ligand, it can coordinate with the metal ion through an ionic bond or a π bond to form a variety of stable metal complexes. The substituted cyclopentadiene prepared in the present invention is also applicable. In addition, the substituted cyclopentadiene prepared in the present invention is also expected to be used as a molecular building block in biomedical synthesis.

[0028] Compared with the prior art, the present application has at least the following beneficial effects:

[0029] 1. The present application uses tetrahydrofuran as a reaction solvent, mixes alkali metal cyclopentadiene with a halogenated hydrocarbon, and performs a substitution reaction under an inert gas atmosphere at a low temperature, thereby effectively controlling the reaction conditions, avoiding overheating of the reaction to cause self-polymerization of cyclopentadiene and substituted cyclopentadiene monomers, and increasing the yield.

[0030] 2. The present application does not require complex solvent components and only uses tetrahydrofuran as a single solvent as the reaction medium, which simplifies the reaction implementation, greatly saves costs, reduces environmental pollution, and is green and environmentally friendly.

[0031] 3. In the product purification process, the present application achieves sample purification by only adjusting the vacuum degree of reduced pressure distillation, avoiding a series of complex process methods such as extraction and drying, and is easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 It is a reaction mechanism diagram of Example 1 of the present application.

[0034] Figure 2 This is the H NMR spectrum of the substituted cyclopentadiene prepared in Example 1 of the present application.

[0035] Figure 3 This is the H NMR spectrum of the substituted cyclopentadiene prepared in Example 2 of the present application. DETAILED DESCRIPTION

[0036] The present invention will be more fully understood through the following detailed description, which should be read in conjunction with the accompanying drawings. Detailed embodiments of the present invention are disclosed herein; however, it should be understood that the disclosed embodiments are only exemplary of the present invention, which can be embodied in various forms. Therefore, the specific functional details disclosed herein should not be interpreted as limiting, but only as the basis of the claims and as a representative basis for teaching those skilled in the art to adopt the present invention in different ways in virtually any appropriate detailed embodiment.

[0037] Example 1

[0038] This embodiment provides a substituted cyclopentadiene, see Figure 1, is the reaction mechanism diagram of this embodiment: alkali metal cyclopentadiene is mixed with halogenated hydrocarbon for substitution reaction, the hydrocarbon group of the halogenated hydrocarbon replaces the metal atom of the alkali metal cyclopentadiene to form a salt, and the alkali metal cyclopentadiene is continued to be added dropwise to react to form by-products and cyclopentadiene, and the remaining halogenated hydrocarbon is continued to react to form n-propyl cyclopentadiene and a small amount of by-products and inorganic salts. The feeding method in this embodiment effectively avoids the risk caused by a large amount of heat release while reducing the generation of multiple substitution by-products and cyclopentadiene. In addition, in the product distillation stage, adding a small amount of inhibitor can effectively avoid the diene addition and polymerization reaction that occurs spontaneously in the product concentration and heating stages.

[0039] Specifically, the preparation method comprises:

[0040] (1) Add 1 L of anhydrous tetrahydrofuran and 325 mL of n-propyl bromide (3.57 mol) to a 3 L jacketed reactor, lower the system temperature to -30°C, and replace the air in the system with nitrogen three times.

[0041] (2) Under nitrogen protection, 1.7 L of a 2 M THF solution of sodium cyclopentadiene (3.4 mol) was slowly added into the system at a rate of 50 mL / min, while maintaining the temperature of the entire system at -20°C.

[0042] (3) After the addition was completed, the reaction was completed by stirring at -20°C at 80 rpm for 1 hour. The refrigeration was turned off and the temperature was gradually restored to room temperature. The stirring was continued for 2 hours, and then the stirring was stopped. The generated solid by-product was allowed to settle naturally at 20°C, and then solid-liquid separation was performed to obtain the liquid phase.

[0043] (4) Add 0.78 g of hydroquinone (7 mmol) to the liquid phase obtained in step (3), stir for 1 hour, heat and control the temperature at 25°C, and distill under reduced pressure to 3 kPa to remove tetrahydrofuran and volatile components.

[0044] (5) The vacuum is reduced to 0.5 kPa to collect the product propylcyclopentadiene. The temperature of the collecting bottle is maintained at -20°C. As the sample distills out slowly, the bottom temperature is gradually increased to 45°C until no product is distilled out. The collected product is n-propylcyclopentadiene.

[0045] In this example, a total of 184 g of n-propylcyclopentadiene was obtained, with a yield of 50%. Figure 2 , is the H NMR spectrum of the product n-propylcyclopentadiene of this example. The product is a mixture of 1-substituted and 2-substituted, with a ratio of about 0.45:0.55. 1 HNMR (400MHz, C6D6): 6.45-5.95 (s, 3H), 2.78-2.66 (s, 2H), 2.28 (m, 2H), 1.53-1.42 (m, 2H), 0.88-0.87 (m, 3H).

[0046] Example 2

[0047] This embodiment provides a substituted cyclopentadiene, the preparation method of which comprises:

[0048] (1) 1.5 L of anhydrous tetrahydrofuran and 363 mL of n-propyl bromide (4.2 mol) were added to a 5 L jacketed reactor, the system temperature was lowered to -30°C, and the gas in the system was replaced with nitrogen three times.

[0049] (2) Under nitrogen protection, 2 L of a 2 M THF solution of sodium cyclopentadiene (4 mol) was slowly added dropwise into the system at a rate of 100 mL / min, while maintaining the temperature of the entire system at -30°C.

[0050] (3) After the addition was completed, the reaction was stirred at -30°C and 150 rpm for 1 hour. The refrigeration was turned off and the temperature was gradually restored to room temperature. The stirring was continued for 2 hours, and then the stirring was stopped. The generated solid by-product was allowed to settle naturally at 25°C, and then the solid-liquid separation was performed to obtain the liquid phase.

[0051] (4) Add 0.88 g of hydroquinone (8 mmol) to the liquid phase obtained in step (3), stir for 2 h, heat and control the temperature at 25° C., and distill under reduced pressure to 5 kPa to remove tetrahydrofuran and volatile components.

[0052] (5) The product propylcyclopentadiene was collected by vacuuming to 1 kPa, and the temperature of the collecting bottle was maintained at about -20°C. As the sample distilled slowly, the bottom temperature was gradually increased to 45°C until no product was distilled out. The collected product was propylcyclopentadiene. In this example, 203.4 g of propylcyclopentadiene was obtained with a yield of 47%. The product was a mixture of 1-substituted and 2-substituted, with a ratio of about 0.45:0.55. 1 H NMR (400MHz, C6D6): 6.45-5.95 (s, 3H), 2.78-2.66 (s, 2H), 2.28 (m, 2H), 1.53-1.42 (m, 2H), 0.88-0.87 (m, 3H).

[0053] Example 3

[0054] This embodiment provides a substituted cyclopentadiene, the preparation method of which comprises:

[0055] (1) Add 100 mL of anhydrous tetrahydrofuran and 38 mL of isopropyl bromide (420 mmol) into a 500 mL jacketed reactor, lower the system temperature to -20°C, and replace the gas in the system with nitrogen three times.

[0056] (2) Under nitrogen protection, 200 mL of a 2 M THF solution of sodium cyclopentadiene (400 mmol) was slowly added dropwise into the system at a rate of 50 mL / min, while maintaining the temperature of the entire system at no more than -20°C.

[0057] (3) After the addition was completed, the reaction was continued at -20°C with stirring at 80 rpm for 1 hour. After the reaction was completed, the refrigeration was turned off and the temperature was gradually restored to room temperature. After stirring for 2 hours, the stirring was stopped and the generated solid by-product was allowed to settle naturally at 20°C. Then, solid-liquid separation was performed to obtain the liquid phase.

[0058] (4) Add 88 mg of hydroquinone (0.8 mmol) to the liquid phase obtained in step (3), stir for 1 hour, heat and control the temperature at 20°C, and distill under reduced pressure to 5 kPa to remove tetrahydrofuran and volatile components.

[0059] (5) The product isopropylcyclopentadiene was collected by vacuuming to 0.5 kPa. The temperature of the collecting bottle was maintained at -25 °C. As the sample distilled slowly, the bottom temperature was gradually increased to 45 °C until no product was distilled out. The collected product was isopropylcyclopentadiene. In this embodiment, 203.4 g of isopropylcyclopentadiene was obtained with a yield of 47%. The product was a mixture of 1-substituted and 2-substituted with a ratio of about 0.37:0.63. 1 H NMR (400MHz, C6D6): 6.52-5.92 (s, 3H), 2.77-2.69 (s, 2H), 2.55 (m, 1H), 1.13-1.04 (m, 6H).

[0060] Example 4

[0061] This embodiment provides a substituted cyclopentadiene, the preparation method of which comprises:

[0062] (1) 1 L of anhydrous tetrahydrofuran and 309 mL of n-propyl bromide (3.4 mol) were added to a 3 L jacketed reactor, the system temperature was lowered to -30°C, and the gas in the system was replaced with nitrogen three times.

[0063] (2) Under nitrogen protection, 1.7 L of a 2 M THF solution of potassium cyclopentadienyl (3.4 mol) was slowly added dropwise into the system at a rate of 50 mL / min, while maintaining the temperature of the entire system at no more than -20°C.

[0064] (3) After the addition was completed, the reaction was stirred at -20°C at 80 rpm for 4 hours, and then the refrigeration was turned off to gradually return the temperature to room temperature. Stirring was continued for 2 hours, and then stirring was stopped. The generated solid by-product was allowed to settle naturally at 20°C, and then solid-liquid separation was performed to obtain the liquid phase.

[0065] (4) Add 1.19 g of tert-butylcatechol (7 mmol) to the liquid phase obtained in step (3), stir for 1 hour, heat to control the temperature at 25°C, and distill under reduced pressure to 3 kPa to remove tetrahydrofuran and volatile components.

[0066] (5) The product propylcyclopentadiene was collected under vacuum to 1 kPa. The temperature of the collecting bottle was maintained at about -30°C. As the sample distilled slowly, the bottom temperature was gradually increased to 45°C until no product was distilled out. The collected product was n-propylcyclopentadiene. In this embodiment, a total of 165 g of n-propylcyclopentadiene was obtained with a yield of 45%. The product was a mixture of 1-substituted and 2-substituted products in a ratio of about 0.46:0.54. 1 H NMR (400MHz, C6D6): 6.45-5.95 (s, 3H), 2.78-2.66 (s, 2H), 2.28 (m, 2H), 1.53-1.42 (m, 2H), 0.88-0.87 (m, 3H).

[0067] Example 5

[0068] This embodiment provides a substituted cyclopentadiene, the preparation method of which comprises:

[0069] (1) Add 1 L of anhydrous tetrahydrofuran and 325 mL of n-propyl bromide (3.57 mol) to a 3 L jacketed reactor, lower the system temperature to -30°C, and replace the gas in the system with nitrogen three times.

[0070] (2) Under nitrogen protection, 1.7 L of a 2 M THF solution of sodium cyclopentadiene (3.4 mol) was slowly added dropwise into the system at a rate of 50 mL / min, while maintaining the temperature of the entire system at no more than -20°C.

[0071] (3) After the addition was completed, the reaction was completed by stirring at -20°C at 80 rpm for 1 hour. The refrigeration was turned off and the temperature was gradually restored to room temperature. The stirring was continued for 2 hours, and then the stirring was stopped. The generated solid by-product was allowed to settle naturally at 20°C, and then solid-liquid separation was performed to obtain the liquid phase.

[0072] (4) Add 1.72 g of 2-sec-butyl-4,6-dinitrophenol (7 mmol) to the liquid phase obtained in step (3), stir for 1 hour, heat and control the temperature at 25°C, and distill under reduced pressure to 3 kPa to remove tetrahydrofuran and volatile components.

[0073] (5) The vacuum was reduced to 0.5 kPa to collect the product propylcyclopentadiene. The temperature of the collecting bottle was maintained at about -30°C. As the sample distilled slowly, the bottom temperature was gradually increased to 45°C until no product was distilled out. The collected product was n-propylcyclopentadiene. In this embodiment, a total of 154 g of n-propylcyclopentadiene was obtained with a yield of 42%. The product was a mixture of 1-substituted and 2-substituted products in a ratio of about 0.43:0.57. 1 H NMR (400MHz, C6D6): 6.45-5.95 (s, 3H), 2.78-2.66 (s, 2H), 2.28 (m, 2H), 1.53-1.42 (m, 2H), 0.88-0.87 (m, 3H).

[0074] Example 6

[0075] This embodiment provides a substituted cyclopentadiene, the preparation method of which comprises:

[0076] (1) 1 L of anhydrous tetrahydrofuran and 309 mL of n-propyl bromide (3.4 mol) were added to a 3 L jacketed reactor, the system temperature was lowered to -30°C, and the gas in the system was replaced with nitrogen three times.

[0077] (2) Under nitrogen protection, 1.7 L of a 2 M THF solution of sodium cyclopentadiene (3.4 mol) was slowly added dropwise into the system at a rate of 50 mL / min, while maintaining the temperature of the entire system at no more than -20°C.

[0078] (3) After the addition was completed, the reaction was completed by stirring at -20°C at 80 rpm for 1 hour. The refrigeration was turned off and the temperature was gradually restored to room temperature. The stirring was continued for 2 hours, and then the stirring was stopped. The generated solid by-product was allowed to settle naturally at 20°C, and then solid-liquid separation was performed to obtain the liquid phase.

[0079] (4) 1.97 g of p-diphenol (17.9 mmol) was added to the liquid phase obtained in step (3), and the mixture was stirred for 1 h. The mixture was heated and the temperature was controlled at 25° C. The mixture was distilled under reduced pressure to 3 kPa to remove tetrahydrofuran and volatile components.

[0080] (5) The product propylcyclopentadiene was collected under vacuum to 1 kPa. The temperature of the collecting bottle was maintained at about -20°C. As the sample distilled slowly, the bottom temperature was gradually increased to 45°C until no product was distilled out. The collected product was n-propylcyclopentadiene. In this embodiment, a total of 154 g of n-propylcyclopentadiene was obtained with a yield of 42%. The product was a mixture of 1-substituted and 2-substituted products in a ratio of about 0.44:0.56. 1H NMR (400MHz, C6D6): 6.45-5.95 (s, 3H), 2.78-2.66 (s, 2H), 2.28 (m, 2H), 1.53-1.42 (m, 2H), 0.88-0.87 (m, 3H).

[0081] Comparative Example 1

[0082] The only difference between Comparative Example 1 and Implementation 1 is that in step (2) of Comparative Example 1, the sodium cyclopentadienyl THF solution is added all at once to the mixed system of anhydrous tetrahydrofuran and n-propyl bromide for reaction, and the other conditions remain the same as Implementation 1.

[0083] During the feeding process of Comparative Example 1, the reaction was highly exothermic, and 55 g of n-propylcyclopentadiene was finally obtained with a yield of 15%. The by-products mainly included oligomers and polymers generated by free radical polymerization and Diels-Alder reaction.

[0084] Comparative Example 2

[0085] The only difference between Comparative Example 2 and Example 1 is that in Comparative Example 2, the mixed solution of anhydrous tetrahydrofuran and n-propyl bromide is added dropwise to the sodium cyclopentadienyl THF solution at a rate of 50 mL / min, and the other conditions remain the same as in Example 1.

[0086] In Comparative Example 2, 126 g of n-propylcyclopentadiene was finally obtained with a yield of 24%. The by-products mainly included polysubstituted cyclopentadiene and polymers.

[0087] The inventors also used the substituted cyclopentadiene prepared in Examples 1-6 as a reactant, and coordinated with the corresponding metal salt or metal organic compound to form a corresponding metal precursor compound, such as bis(n-propylcyclopentadienyl)magnesium, or isopropylcyclopentadienyl hafnium trichloride.

[0088] In summary, the present invention drips an alkali metal cyclopentadienyl furan solution into a mixture of a halogenated hydrocarbon and a furan solution for reaction, effectively controls the reaction conditions through a reasonable adding sequence, avoids monomer self-polymerization caused by overheating of the reaction, and improves the yield; during the reaction process, only tetrahydrofuran is used as a reaction medium, thus saving costs and reducing environmental pollution; in the product purification link, sample purification is achieved only through reduced pressure distillation, thus avoiding complex extraction, drying and other processes, and greatly simplifying the preparation process.

[0089] The various aspects, embodiments, features and examples of the present invention should be considered as illustrative in all aspects and are not intended to limit the present invention, the scope of the present invention is defined only by the claims. Other embodiments, modifications and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed invention.

Claims

1. A method for preparing substituted cyclopentadiene, characterized in that: include: Using tetrahydrofuran as the reaction solvent, the alkali metal cyclopentadiene is mixed with the halogenated hydrocarbon, and a substitution reaction is carried out under the conditions of an inert gas atmosphere and a temperature of -30°C to -20°C, so that the metal atom in the alkali metal cyclopentadiene is replaced by the hydrocarbon group of the halogenated hydrocarbon to obtain a substituted cyclopentadiene.

2. The method for preparing a substituted cyclopentadiene according to claim 1, characterized in that: The specific steps include: S1. Providing a mixture of anhydrous tetrahydrofuran and a halogenated hydrocarbon; S2. providing an alkali metal cyclopentadienylfuran solution; S3. Substitution reaction: in an inert gas atmosphere, the alkali metal cyclopentadiene furan solution is added dropwise to the mixture to form a mixed reaction system, and the substitution reaction is carried out under stirring at a temperature of -30°C to -20°C, so that the metal atom in the alkali metal cyclopentadiene is replaced by the hydrocarbon group of the halogenated hydrocarbon to obtain a reaction product; S4. Post-treatment: performing solid-liquid separation on the reaction product to obtain a liquid phase, adding a polymerization inhibitor to the liquid phase, and obtaining substituted cyclopentadiene after distillation.

3. The method for preparing a substituted cyclopentadiene according to claim 2, wherein: In S1, the temperature of the mixture of anhydrous tetrahydrofuran and halogenated hydrocarbon is -30°C to -20°C; In S3, the temperature at which the alkali metal cyclopentadienylfuran solution is added dropwise is -30°C to -20°C; In S3, the dropping speed of the alkali metal cyclopentadiene tetrahydrofuran solution is 50-100 mL / min; And / or, the reaction time of the substitution reaction is 1h to 4h; And / or, the molar ratio of the alkali metal cyclopentadiene to the halogenated hydrocarbon is 0.95 to 1:

1.

4. The method for preparing a substituted cyclopentadiene according to claim 2, wherein: In S4, the substituted cyclopentadiene includes a mixture of 1-substituted products and 2-substituted products, and the molar ratio of the 1-substituted product to the 2-substituted product is 0.45:0.55-0.37:0.

63.

5. The method for preparing cyclopentadiene according to claim 2, characterized in that: The alkali metal cyclopentadiene furan solution comprises a mixture of cyclopentadiene containing sodium or potassium and furan; And / or, the chemical formula of the halogenated hydrocarbon is RX, wherein R is a hydrocarbon group, including any one of n-propyl, isopropyl, and n-butyl; X is a halogen atom or OTs, and the halogen atom includes Br or I; And / or, the polymerization inhibitor includes at least any one of hydroquinone, tert-butylcatechol, and 2-sec-butyl-4,6-dinitrophenol.

6. The method for preparing a substituted cyclopentadiene according to claim 2, characterized in that: In S4, the post-processing step includes solid-liquid separation and distillation purification; The solid-liquid separation includes continuing to stir the reaction product for 1 hour to 2 hours after the reaction is completed, then restoring the temperature to 20° C. to 25° C. and allowing the product to stand, and performing solid-liquid separation after precipitation to obtain the liquid phase; The distillation purification includes adding a polymerization inhibitor into the liquid phase and then distilling to obtain substituted cyclopentadiene.

7. The method for preparing a substituted cyclopentadiene according to claim 6, characterized in that: The stirring speed during the solid-liquid separation is 80-150 rpm; And / or, the distillation purification comprises: after adding the polymerization inhibitor, stirring for 1 to 4 hours, and distilling at a temperature of 20° C. to 25° C. and a pressure of 3 to 5 kPa; And / or, the molar ratio of the polymerization inhibitor to the halogenated hydrocarbon is 0.002-0.005:

1.

8. The method for preparing a substituted cyclopentadiene according to claim 7, characterized in that: In the distillation purification, the receiving conditions of the distillation product include a vacuum degree of 0.5-1 kPa and a receiving temperature of -30 to -20°C.

9. A substituted cyclopentadiene, characterized in that: The substituted cyclopentadiene is prepared by the preparation method of substituted cyclopentadiene as described in any one of claims 1 to 8.

10. Use of the substituted cyclopentadiene according to claim 9 in the field of preparing metal precursors.

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