Preparation method of cyclopentadienyl tris (dimethylamino) hafnium

Abstract

The invention provides a preparation method of cyclopentadienyl tris (dimethylamino) hafnium, which comprises the following steps: (1) mixing a hydrocarbon solvent, hafnium tetrachloride and dimethylamine, and adding an alkali metal compound for reaction; and (2) adding cyclopentadiene into the reaction liquid in the step (1), and reacting to obtain the cyclopentadienyl tris (dimethylamino) hafnium, the alkali metal compound is n-butyllithium. The preparation method comprises the following steps: preferentially mixing hafnium tetrachloride and dimethylamine, then dropwise adding n-butyllithium to prepare tetra (dimethylamino) hafnium, and adding cyclopentadiene to obtain the product. According to the method, the synthesis steps of the product are reduced, the reaction time is shortened, and the yield and the purity are improved.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis technology and relates to a method for preparing cyclopentadienyltris(dimethylamino)hafnium. Background Technology

[0002] With the development of microelectronics technology, the size of semiconductor devices is constantly shrinking. However, due to the inherent limitations of traditional SiO2 materials, more and more performance problems are emerging in these devices. For example, as the gate thickness decreases, leakage current increases, leading to increased power consumption; and it is difficult to precisely control the threshold voltage of polycrystalline silicon gates at the nanoscale.

[0003] Hafnium oxide, as a metal-based material, has a dielectric constant much higher than that of SiO2, giving it significant advantages in various applications. For example, in logic chips, when used as a gate dielectric layer, it can significantly reduce gate leakage current, improve device switching performance and reliability, and simultaneously reduce power consumption. In DRAM, the introduction of hafnium oxide ensures a thicker dielectric layer for the same capacitance, thereby suppressing leakage current caused by quantum tunneling and increasing data retention time.

[0004] Cyclopentadienyl tris(dimethylamino)hafnium, as a novel precursor material for preparing hafnium oxide, is a liquid at room temperature with a relatively high vapor pressure. Compared to tetra(methylethylamino)hafnium, the introduction of cyclopentadienyl groups greatly increases its thermal stability.

[0005] Currently, there are several methods for synthesizing cyclopentadienyl tris(dimethylamino)hafnium. CN114957345A discloses one method: first, cyclopentadienyl hafnium trichloride is synthesized in two steps, and then it is reacted with pre-prepared dimethylaminolithium to obtain cyclopentadienyl tris(dimethylamino)hafnium. This reaction is not only cumbersome but also has a low yield. CN119684373A discloses another method: first, dimethylaminolithium is prepared from n-butyllithium and dimethylamine, then reacted with hafnium tetrachloride to obtain tetra(dimethylamino)hafnium, and finally cyclopentadiene is added to obtain cyclopentadienyl tris(dimethylamino)hafnium. This method can achieve a yield of up to 65%, but it involves many reaction steps and a long reaction time.

[0006] Therefore, developing a convenient and efficient method for preparing cyclopentadienyltris(dimethylamino)hafnium with fewer reaction steps, shorter reaction time, and higher product yield and purity is a technical problem to be solved in this field. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing cyclopentadienyltris(dimethylamino)hafnium. This invention preferentially mixes hafnium tetrachloride and dimethylamine, then adds n-butyllithium dropwise to obtain tetra(dimethylamino)hafnium, and finally adds cyclopentadiene to obtain the product. This method not only reduces the number of synthesis steps but also shortens the reaction time, and improves the yield and purity.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] On one hand, the present invention provides a method for preparing cyclopentadienyltris(dimethylamino)hafnium, the method comprising the following steps:

[0010] (1) Mix hydrocarbon solvent, hafnium tetrachloride and dimethylamine, and add alkali metal compound to react;

[0011] (2) Add cyclopentadiene to the reaction solution in step (1) and react to obtain the cyclopentadienyl tris(dimethylamino)hafnium;

[0012] The alkali metal compound is n-butyllithium.

[0013] The synthetic route of the preparation method provided by this invention is as follows:

[0014]

[0015] The method for preparing cyclopentadienyltris(dimethylamino)hafnium provided by this invention, by changing the order of addition and adding n-butyllithium dropwise to a mixed solution of hafnium tetrachloride, dimethylamine and hydrocarbon reagents, not only reduces the number of reaction steps and shortens the reaction time, but also improves the yield and purity of cyclopentadienyltris(dimethylamino)hafnium.

[0016] Preferably, the hydrocarbon solvent in step (1) includes C5-C64 ...-C64-C64-C64-C64-C64-C64-C64-C64-C6 12 Alkanes (e.g., C5 alkanes, C6 alkanes, C7 alkanes, C8 alkanes, C9 alkanes, C4 alkanes, C5 alkanes, C6 alkanes, C7 alkanes, C8 alkanes, C9 ...9 alkanes, C9 alkanes, C9 alkanes, C9 alkanes, C9 alkan 10 Alkanes, C 11 Alkanes or C 12 Alkanes), C6-C 14 Aromatic hydrocarbons (e.g., C6 aromatic hydrocarbons, C9 aromatic hydrocarbons, C4 aromatic hydrocarbons, C5 aromatic hydrocarbons) 10 Aromatics, C 12 Aromatics or C 14 (Aromatics, etc.)

[0017] Preferably, the hydrocarbon solvent in step (1) includes any one or a combination of at least two of n-pentane, n-hexane, n-heptane, benzene or toluene, preferably n-pentane, n-hexane or n-heptane, and more preferably n-hexane.

[0018] The preferred hydrocarbon solvents used in this invention are n-pentane, n-hexane, and n-heptane, which reduce reaction costs, are non-coordinated, and are non-toxic to humans.

[0019] Preferably, the mixing in step (1) is carried out under stirring.

[0020] Preferably, the system is cooled before adding the n-butyllithium in step (1).

[0021] Preferably, the cooling is to a temperature of -78℃ to -10℃, for example, -78℃, -70℃, -65℃, -60℃, -50℃, -40℃, -30℃, -20℃ or -10℃, etc.

[0022] Preferably, the n-butyllithium in step (1) is added by constant pressure dropwise addition.

[0023] In this application, the addition of n-butyllithium using a constant-pressure dropping method is beneficial for controlling the temperature of the reaction system. This not only avoids the risk of byproducts caused by local heat accumulation, but also ensures that the raw materials are in full contact with each other, thereby improving the yield.

[0024] Preferably, the system temperature is controlled to be below -10°C during the addition of n-butyllithium in step (1).

[0025] Preferably, the molar ratio of n-butyllithium to hafnium tetrachloride in step (1) is (4-8):1, for example, it can be 4:1, 4.12:1, 4.15:1, 4.18:1, 4.2:1, 4.5:1, 5:1, 6:1, 7:1 or 8:1, and more preferably (4-4.3):1.

[0026] In this invention, the molar ratio of dimethylamine to alkali metal compound in step (1) is (1-1.8):1, for example 1:1, 1.2:1, 1.4:1, 1.5:1, 1.7:1 or 1.8:1. A specific molar ratio of dimethylamine to alkali metal compound is beneficial to improving the yield of the target product and reducing production costs. When the molar ratio is (1-1.2):1 (for example 1:1, 1.05:1, 1.1:1, 1.15:1 or 1.2:1), the best technical effect is achieved. If the molar ratio is lower than 1:1, it will lead to the formation of tetrabutylhafnium byproduct, reducing the product yield. If the molar ratio is higher than 1.2:1, it will cause waste of the raw material dimethylamine and increase the cost of product synthesis.

[0027] Preferably, the reaction temperature in step (1) is -78℃ to room temperature, for example, it can be -78℃, -70℃, -65℃, -60℃, -50℃, -40℃, -30℃, -20℃, -10℃, 0℃, 5℃, 10℃, 15℃, 20℃, 25℃ or 30℃, preferably room temperature (i.e. 15℃-30℃).

[0028] The preparation method provided by the present invention has a wide reaction temperature range in step (1), which can be adjusted according to the actual production situation; at the same time, this specific temperature range indicates that the preparation method does not require extremely low temperature during the preparation process, and -10℃ can meet the requirements, thus reducing energy consumption.

[0029] Preferably, the reaction time in step (1) is 4 to 24 hours, for example, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours, 10 hours, 15 hours or 20 hours, preferably 4 to 12 hours, and more preferably 4 to 8 hours.

[0030] Preferably, the molar ratio of cyclopentadiene in step (2) to hafnium tetrachloride in step (1) is (1-4):1, for example, it can be 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 2:1, 3:1 or 4:1, etc., and more preferably (1-1.1):1.

[0031] In this invention, a specific molar ratio of cyclopentadiene to hafnium tetrachloride is beneficial to improving the yield of the target product. The best technical effect is achieved when the molar ratio is (1-1.1):1. If the molar ratio is lower than 1:1, the tetra(dimethylamino)hafnium intermediate generated in step one cannot be used to generate the product, reducing the product yield and introducing impurities. If the molar ratio is higher than 1.1:1, the excess cyclopentadiene will react with the product to generate dicyclopentadienyl di(dimethylamino)hafnium, reducing the product yield and purity.

[0032] In this invention, the addition of cyclopentadiene using a constant-pressure dropping method is beneficial for controlling the temperature of the reaction system. This not only avoids the risk of byproducts caused by local heat accumulation, but also ensures that the raw materials are in full contact with each other, thereby improving the yield.

[0033] Preferably, the temperature of the reaction system is controlled to be below 10°C during the addition of cyclopentadiene in step (2).

[0034] Preferably, both the reaction in step (1) and the reaction in step (2) are carried out under a protective gas atmosphere.

[0035] Preferably, the protective gas includes any one or a combination of at least two of nitrogen, argon, or helium.

[0036] Preferably, after the reaction in step (2) is completed, the hydrocarbon solvent is first removed by atmospheric distillation, and then the fraction at 100℃ / 0.4mmHg is collected by vacuum distillation to obtain the cyclopentadienyltris(dimethylamino)hafnium.

[0037] In the specific preparation method provided by this invention, after the synthesis reaction is completed, there is no need to filter to remove the corresponding inorganic salts. The desired target product can be obtained directly by atmospheric distillation and vacuum distillation, which simplifies the experimental operation and improves the production efficiency.

[0038] Preferably, the preparation method of the cyclopentadienyltris(dimethylamino)hafnium specifically includes the following steps:

[0039] (1) Under a protective gas atmosphere, a hydrocarbon solvent, hafnium tetrachloride and dimethylamine were mixed, cooled to -78℃~-10℃, and n-butyllithium was added dropwise under constant pressure. The system temperature was controlled to react at room temperature for 4~24h.

[0040] The hydrocarbon solvent includes C5-C. 12 Alkanes, C6-C 14 Aromatic hydrocarbons; the molar ratio of dimethylamine to hafnium tetrachloride is (4-8):1; the molar ratio of n-butyllithium to hafnium tetrachloride is (4-8):1; and the molar ratio of dimethylamine to alkali metal compound is (1-1.8):1.

[0041] (2) Add cyclopentadiene to the reaction solution in step (1), and control the temperature of the reaction system to be below 10°C. After the cyclopentadiene is added, the reaction system is reacted at room temperature for 4 to 18 hours under a protective gas atmosphere. After the reaction is completed, the hydrocarbon solvent is removed by atmospheric distillation, and then the fraction at 100°C / 0.4 mmHg is collected by vacuum distillation to obtain the cyclopentadienyl tris(dimethylamino)hafnium.

[0042] The molar ratio of cyclopentadiene in step (2) to hafnium tetrachloride in step (1) is (1-4):1.

[0043] Compared with the prior art, the present invention has at least the following beneficial effects:

[0044] The method for preparing cyclopentadienyltris(dimethylamino)hafnium provided by this invention changes the order of addition. First, hafnium tetrachloride, hydrocarbon reagents, and dimethylamine are mixed and then n-butyllithium is added, followed by the addition of cyclopentadiene to obtain the product. This method not only shortens the reaction steps, requiring only two steps to obtain the product, but also shortens the reaction time and improves the yield and purity of cyclopentadienyltris(dimethylamino)hafnium. Detailed Implementation

[0045] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0046] Example 1

[0047] This embodiment provides a method for preparing cyclopentadienyltris(dimethylamino)hafnium, the method comprising the following steps:

[0048] (1) Under N2 atmosphere, hafnium tetrachloride (100g, 0.31mol) and 150mL of n-hexane were added to a 500mL reaction flask, the temperature was lowered to -20℃, dimethylamine gas (56.3g, 1.25mol) was introduced into the reaction flask, and then n-butyllithium (500mL, 1.25mol, 2.5M n-hexane solution) was slowly added to the reaction flask through a constant pressure dropping funnel, the temperature of the reaction system was controlled to be below -10℃ during the addition, and then the reaction was carried out at 25℃ for 8h.

[0049] (2) Freshly collected cyclopentadiene (20.6 g, 0.31 mol) was slowly added dropwise into the reaction flask through a constant-pressure dropping funnel, keeping the temperature of the reaction system below 10 °C during the addition. After the addition of cyclopentadiene, the reaction was carried out at room temperature for 6 h under a N2 atmosphere. After the reaction was completed, the apparatus was replaced with an atmospheric distillation apparatus to remove n-hexane at 70 °C, yielding a mixture of the product and inorganic salt. Subsequently, the apparatus was replaced with a vacuum distillation apparatus, and the fraction at 100 °C / 0.4 mmHg was collected to obtain 8.22 g of cyclopentadienyltris(dimethylamino)hafnium.

[0050] The NMR spectrum of the compound cyclopentadienyltris(dimethylamino)hafnium showed no obvious impurity peaks, and its characterization data are as follows:

[0051] 1 H NMR (400MHz, C6D6-d6): δ6.04 (s, 5H), 2.96 (s, 18H).

[0052] Example 2

[0053] This embodiment provides a method for preparing cyclopentadienyltris(dimethylamino)hafnium, the method comprising the following steps:

[0054] (1) Under N2 atmosphere, hafnium tetrachloride (100g, 0.31mol) and 150mL of n-hexane were added to a 500mL reaction flask, the temperature was lowered to -20℃, dimethylamine gas (70.4g, 1.56mol) was introduced into the reaction flask, and then n-butyllithium (500mL, 1.25mol, 2.5M n-hexane solution) was slowly added to the reaction flask through a constant pressure dropping funnel, and the temperature of the reaction system was controlled to be below -10℃ during the addition. Then the reaction was carried out at 25℃ for 8h.

[0055] (2) Freshly collected cyclopentadiene (20.6 g, 0.31 mol) was slowly added dropwise into the reaction flask through a constant-pressure dropping funnel, keeping the temperature of the reaction system below 10 °C during the addition. After the addition of cyclopentadiene, the reaction was carried out at room temperature for 6 h under a N2 atmosphere. After the reaction was completed, the apparatus was replaced with an atmospheric distillation apparatus to remove n-hexane at 70 °C, yielding a mixture of the product and inorganic salt. Subsequently, the apparatus was replaced with a vacuum distillation apparatus, and the fraction at 100 °C / 0.4 mmHg was collected to obtain 8.68 g of cyclopentadienyltris(dimethylamino)hafnium.

[0056] The NMR spectrum of the compound cyclopentadienyltris(dimethylamino)hafnium showed no obvious impurity peaks, and its characterization data are as follows:

[0057] 1 H NMR (400MHz, C6D6-d6): δ6.04 (s, 5H), 2.96 (s, 18H).

[0058] Example 3

[0059] This embodiment provides a method for preparing cyclopentadienyltris(dimethylamino)hafnium, the method comprising the following steps:

[0060] (1) Under N2 atmosphere, hafnium tetrachloride (100g, 0.31mol) and 150mL of n-hexane were added to a 500mL reaction flask, the temperature was lowered to -20℃, dimethylamine gas (84.4g, 1.87mol) was introduced into the reaction flask, and then n-butyllithium (500mL, 1.25mol, 2.5M n-hexane solution) was slowly added dropwise into the reaction flask through a constant pressure dropping funnel, the temperature of the reaction system was controlled to be below -10℃ during the addition, and then the reaction was carried out at 25℃ for 8h.

[0061] (2) Freshly collected cyclopentadiene (20.6 g, 0.31 mol) was slowly added dropwise to the reaction flask through a constant-pressure dropping funnel, keeping the temperature of the reaction system below 10 °C during the addition. After the addition of cyclopentadiene, the reaction was carried out at room temperature for 6 h under a N2 atmosphere. After the reaction was completed, the apparatus was replaced with an atmospheric distillation apparatus to remove n-hexane at 70 °C, yielding a mixture of the product and inorganic salt. Subsequently, the apparatus was replaced with a vacuum distillation apparatus, and the fraction at 100 °C / 0.4 mmHg was collected to obtain 8.60 g of cyclopentadienyltris(dimethylamino)hafnium.

[0062] The NMR spectrum of the compound cyclopentadienyltris(dimethylamino)hafnium showed no obvious impurity peaks, and its characterization data are as follows:

[0063] 1 H NMR (400MHz, C6D6-d6): δ6.04 (s, 5H), 2.96 (s, 18H).

[0064] Example 4

[0065] This embodiment provides a method for preparing cyclopentadienyltris(dimethylamino)hafnium, the method comprising the following steps:

[0066] (1) Under N2 atmosphere, hafnium tetrachloride (100g, 0.31mol) and 1L of n-hexane were added to a 5L reaction flask, the temperature was lowered to -20℃, dimethylamine gas (70.3g, 1.56mol) was introduced into the reaction flask, and then n-butyllithium (524.5mL, 1.31mol, 2.5M n-hexane solution) was slowly added dropwise into the reaction flask through a constant pressure dropping funnel, and the temperature of the reaction system was controlled to be below -10℃ during the addition. Then the reaction was carried out at room temperature for 8h.

[0067] (2) Freshly collected cyclopentadiene (20.6 g, 0.31 mol) was slowly added dropwise to the reaction flask through a constant-pressure dropping funnel, keeping the temperature of the reaction system below 10 °C during the addition. After the addition of cyclopentadiene, the reaction was carried out at room temperature for 6 h under a N2 atmosphere. After the reaction was completed, the apparatus was replaced with an atmospheric distillation apparatus to remove n-hexane at 70 °C, yielding a mixture of the product and inorganic salt. Subsequently, the apparatus was replaced with a vacuum distillation apparatus, and the fraction at 100 °C / 0.4 mmHg was collected to obtain 9.83 g of cyclopentadienyltris(dimethylamino)hafnium.

[0068] The NMR spectrum of the compound cyclopentadienyltris(dimethylamino)hafnium showed no obvious impurity peaks, and its characterization data are as follows:

[0069] 1 H NMR (400MHz, C6D6-d6): δ6.04 (s, 5H), 2.96 (s, 18H).

[0070] Example 5

[0071] This embodiment provides a method for preparing cyclopentadienyltris(dimethylamino)hafnium, the method comprising the following steps:

[0072] (1) Under N2 atmosphere, hafnium tetrachloride (100g, 0.31mol) and 1L of n-hexane were added to a 5L reaction flask, cooled to -20℃, and dimethylamine gas (84.4g, 1.87mol) was introduced into the reaction flask. Then, n-butyllithium (524.5mL, 1.31mol, 2.5M n-hexane solution) was slowly added to the reaction flask through a constant pressure dropping funnel. The temperature of the reaction system was controlled to be below -10℃ during the addition. The reaction was then carried out at room temperature for 8h.

[0073] (2) Freshly collected cyclopentadiene (20.6 g, 0.31 mol) was slowly added dropwise into the reaction flask through a constant-pressure dropping funnel, keeping the temperature of the reaction system below 10 °C during the addition. After the addition of cyclopentadiene, the reaction was carried out at room temperature for 6 h under a N2 atmosphere. After the reaction was completed, the apparatus was replaced with an atmospheric distillation apparatus to remove n-hexane at 70 °C, yielding a mixture of the product and inorganic salt. Subsequently, the apparatus was replaced with a vacuum distillation apparatus, and the fraction at 100 °C / 0.4 mmHg was collected to obtain 9.60 g of cyclopentadienyltris(dimethylamino)hafnium.

[0074] The NMR spectrum of the compound cyclopentadienyltris(dimethylamino)hafnium showed no obvious impurity peaks, and its characterization data are as follows:

[0075] 1 H NMR (400MHz, C6D6-d6): δ6.04 (s, 5H), 2.96 (s, 18H).

[0076] Example 6

[0077] This embodiment provides a method for preparing cyclopentadienyltris(dimethylamino)hafnium, the method comprising the following steps:

[0078] (1) Under N2 atmosphere, hafnium tetrachloride (100g, 0.31mol) and 1L of n-hexane were added to a 5L reaction flask, cooled to -20℃, and dimethylamine gas (70.4g, 1.56mol) was introduced into the reaction flask. Then, n-butyllithium (524.5mL, 1.31mol, 2.5M n-hexane solution) was slowly added to the reaction flask through a constant pressure dropping funnel. The temperature of the reaction system was controlled to be below -10℃ during the addition. The reaction was then carried out at room temperature for 8h.

[0079] (2) Freshly collected cyclopentadiene (24.8 g, 0.37 mol) was slowly added dropwise into the reaction flask through a constant-pressure dropping funnel, keeping the temperature of the reaction system below 10 °C during the addition. After the addition of cyclopentadiene, the reaction was carried out at room temperature for 6 h under a N2 atmosphere. After the reaction was completed, the apparatus was replaced with an atmospheric distillation apparatus to remove n-hexane at 70 °C, yielding a mixture of the product and inorganic salt. Subsequently, the apparatus was replaced with a vacuum distillation apparatus, and the fraction at 100 °C / 0.4 mmHg was collected to obtain 8.91 g of cyclopentadienyltris(dimethylamino)hafnium.

[0080] The NMR spectrum of the compound cyclopentadienyltris(dimethylamino)hafnium showed no obvious impurity peaks, and its characterization data are as follows:

[0081] 1 H NMR (400MHz, C6D6-d6): δ6.04 (s, 5H), 2.96 (s, 18H).

[0082] Example 7

[0083] This embodiment provides a method for preparing cyclopentadienyltris(dimethylamino)hafnium, the method comprising the following steps:

[0084] (1) Under N2 atmosphere, hafnium tetrachloride (100g, 0.31mol) and 1L of n-hexane were added to a 5L reaction flask, cooled to -20℃, and dimethylamine gas (70.4g, 1.56mol) was introduced into the reaction flask. Then, n-butyllithium (524.5mL, 1.31mol, 2.5M n-hexane solution) was slowly added to the reaction flask through a constant pressure dropping funnel. The temperature of the reaction system was controlled to be below -10℃ during the addition. The reaction was then carried out at room temperature for 8h.

[0085] (2) Freshly collected cyclopentadiene (18.6 g, 0.28 mol) was slowly added dropwise to the reaction flask through a constant-pressure dropping funnel, keeping the temperature of the reaction system below 10 °C during the addition. After the addition of cyclopentadiene, the reaction was carried out at room temperature for 6 h under a N2 atmosphere. After the reaction was completed, the apparatus was replaced with an atmospheric distillation apparatus to remove n-hexane at 70 °C, yielding a mixture of the product and inorganic salt. Subsequently, the apparatus was replaced with a vacuum distillation apparatus, and the fraction at 100 °C / 0.4 mmHg was collected to obtain 8.80 g of cyclopentadienyltris(dimethylamino)hafnium.

[0086] The NMR spectrum of the compound cyclopentadienyltris(dimethylamino)hafnium showed no obvious impurity peaks, and its characterization data are as follows:

[0087] 1 H NMR (400MHz, C6D6-d6): δ6.04 (s, 5H), 2.96 (s, 18H).

[0088] Example 8

[0089] This embodiment provides a method for preparing cyclopentadienyltris(dimethylamino)hafnium, the method comprising the following steps:

[0090] (1) Under N2 atmosphere, hafnium tetrachloride (100g, 0.31mol) and 1L of n-hexane were added to a 5L reaction flask, the temperature was lowered to -78℃, dimethylamine gas (70.4g, 1.56mol) was introduced into the reaction flask, and then n-butyllithium (524.5mL, 1.31mol, 2.5M n-hexane solution) was slowly added dropwise into the reaction flask through a constant pressure dropping funnel, and the temperature of the reaction system was controlled to be below -10℃ during the addition. Then the reaction was carried out at -78℃ for 8h.

[0091] (2) Freshly collected cyclopentadiene (20.6 g, 0.31 mol) was slowly added dropwise into the reaction flask through a constant-pressure dropping funnel, keeping the temperature of the reaction system below 10 °C during the addition. After the addition of cyclopentadiene, the reaction was carried out at room temperature for 6 h under a N2 atmosphere. After the reaction was completed, the apparatus was replaced with an atmospheric distillation apparatus to remove n-hexane at 70 °C, yielding a mixture of the product and inorganic salt. Subsequently, the apparatus was replaced with a vacuum distillation apparatus, and the fraction at 100 °C / 0.4 mmHg was collected to obtain 4.17 g of cyclopentadienyltris(dimethylamino)hafnium.

[0092] The NMR spectrum of the compound cyclopentadienyltris(dimethylamino)hafnium showed no obvious impurity peaks, and its characterization data are as follows:

[0093] 1 H NMR (400MHz, C6D6-d6): δ6.04 (s, 5H), 2.96 (s, 18H).

[0094] Example 9

[0095] This embodiment provides a method for preparing cyclopentadienyltris(dimethylamino)hafnium, the method comprising the following steps:

[0096] (1) Under N2 atmosphere, hafnium tetrachloride (100g, 0.31mol) and 1L of n-hexane were added to a 5L reaction flask, cooled to -50℃, and dimethylamine gas (70.4g, 1.56mol) was introduced into the reaction flask. Then, n-butyllithium (524.5mL, 1.31mol, 2.5M n-hexane solution) was slowly added to the reaction flask through a constant pressure dropping funnel. The temperature of the reaction system was controlled to be below -10℃ during the addition. The reaction was then carried out at -50℃ for 8h.

[0097] (2) Freshly collected cyclopentadiene (20.6 g, 0.31 mol) was slowly added dropwise to the reaction flask through a constant-pressure dropping funnel, keeping the temperature of the reaction system below 10 °C during the addition. After the addition of cyclopentadiene, the reaction was carried out at room temperature for 6 h under a N2 atmosphere. After the reaction was completed, the apparatus was replaced with an atmospheric distillation apparatus to remove n-hexane at 70 °C, yielding a mixture of the product and inorganic salt. Subsequently, the apparatus was replaced with a vacuum distillation apparatus, and the fraction at 100 °C / 0.4 mmHg was collected to obtain 5.32 g of cyclopentadienyltris(dimethylamino)hafnium.

[0098] The NMR spectrum of the compound cyclopentadienyltris(dimethylamino)hafnium showed no obvious impurity peaks, and its characterization data are as follows:

[0099] 1 H NMR (400MHz, C6D6-d6): δ6.04 (s, 5H), 2.96 (s, 18H).

[0100] Example 10

[0101] This embodiment provides a method for preparing cyclopentadienyltris(dimethylamino)hafnium, the method comprising the following steps:

[0102] (1) Under N2 atmosphere, hafnium tetrachloride (100g, 0.31mol) and 1L of n-hexane were added to a 5L reaction flask, cooled to -30℃, and dimethylamine gas (70.4g, 1.56mol) was introduced into the reaction flask. Then, n-butyllithium (524.5mL, 1.31mol, 2.5M n-hexane solution) was slowly added to the reaction flask through a constant pressure dropping funnel. The temperature of the reaction system was controlled to be below -10℃ during the addition. The reaction was then carried out at -30℃ for 8h.

[0103] (2) Freshly collected cyclopentadiene (20.6 g, 0.31 mol) was slowly added dropwise into the reaction flask through a constant-pressure dropping funnel, keeping the temperature of the reaction system below 10 °C during the addition. After the addition of cyclopentadiene, the reaction was carried out at room temperature for 6 h under a N2 atmosphere. After the reaction was completed, the apparatus was replaced with an atmospheric distillation apparatus to remove n-hexane at 70 °C, yielding a mixture of the product and inorganic salt. Subsequently, the apparatus was replaced with a vacuum distillation apparatus, and the fraction at 100 °C / 0.4 mmHg was collected to obtain 6.19 g of cyclopentadienyltris(dimethylamino)hafnium.

[0104] The NMR spectrum of the compound cyclopentadienyltris(dimethylamino)hafnium showed no obvious impurity peaks, and its characterization data are as follows:

[0105] 1 H NMR (400MHz, C6D6-d6): δ6.04 (s, 5H), 2.96 (s, 18H).

[0106] Example 11

[0107] This embodiment provides a method for preparing cyclopentadienyltris(dimethylamino)hafnium, the method comprising the following steps:

[0108] (1) Under N2 atmosphere, hafnium tetrachloride (100g, 0.31mol) and 1L of n-hexane were added to a 5L reaction flask, cooled to -20℃, and dimethylamine gas (70.4g, 1.56mol) was introduced into the reaction flask. Then, n-butyllithium (524.5mL, 1.31mol, 2.5M n-hexane solution) was slowly added to the reaction flask through a constant pressure dropping funnel. The temperature of the reaction system was controlled to be below -10℃ during the addition, and then the reaction was carried out at 0℃ for 8h.

[0109] (2) Freshly collected cyclopentadiene (20.6 g, 0.31 mol) was slowly added dropwise to the reaction flask through a constant-pressure dropping funnel, keeping the temperature of the reaction system below 10 °C during the addition. After the addition of cyclopentadiene, the reaction was carried out at room temperature for 6 h under a N2 atmosphere. After the reaction was completed, the apparatus was replaced with an atmospheric distillation apparatus to remove n-hexane at 70 °C, yielding a mixture of the product and inorganic salt. Subsequently, the apparatus was replaced with a vacuum distillation apparatus, and the fraction at 100 °C / 0.4 mmHg was collected to obtain 8.02 g of cyclopentadienyltris(dimethylamino)hafnium.

[0110] The NMR spectrum of the compound cyclopentadienyltris(dimethylamino)hafnium showed no obvious impurity peaks, and its characterization data are as follows:

[0111] 1 H NMR (400MHz, C6D6-d6): δ6.04 (s, 5H), 2.96 (s, 18H).

[0112] Example 12

[0113] This embodiment provides a method for preparing cyclopentadienyltris(dimethylamino)hafnium, the method comprising the following steps:

[0114] (1) Under N2 atmosphere, hafnium tetrachloride (100g, 0.31mol) and 1L of n-hexane were added to a 5L reaction flask, cooled to -20℃, and dimethylamine gas (70.4g, 1.56mol) was introduced into the reaction flask. Then, n-butyllithium (524.5mL, 1.31mol, 2.5M n-hexane solution) was slowly added to the reaction flask through a constant pressure dropping funnel. The temperature of the reaction system was controlled to be below -10℃ during the addition. The reaction was then carried out at room temperature for 12h.

[0115] (2) Freshly collected cyclopentadiene (20.6 g, 0.31 mol) was slowly added dropwise into the reaction flask through a constant-pressure dropping funnel, keeping the temperature of the reaction system below 10 °C during the addition. After the addition of cyclopentadiene, the reaction was carried out at room temperature for 6 h under a N2 atmosphere. After the reaction was completed, the apparatus was replaced with an atmospheric distillation apparatus to remove n-hexane at 70 °C, yielding a mixture of the product and inorganic salt. Subsequently, the apparatus was replaced with a vacuum distillation apparatus, and the fraction at 100 °C / 0.4 mmHg was collected to obtain 9.65 g of cyclopentadienyltris(dimethylamino)hafnium.

[0116] The NMR spectrum of the compound cyclopentadienyltris(dimethylamino)hafnium showed no obvious impurity peaks, and its characterization data are as follows:

[0117] 1 H NMR (400MHz, C6D6-d6): δ6.04 (s, 5H), 2.96 (s, 18H).

[0118] Comparative Example 1

[0119] (1) Under N2 atmosphere, hafnium tetrachloride (100g, 0.31mol) and 1L of n-hexane were added to a 5L reaction flask and cooled to -20℃. Then, n-butyllithium (524.5mL, 1.31mol, 2.5M n-hexane solution) was slowly added to the reaction flask through a constant pressure dropping funnel. The temperature of the reaction system was controlled to be below -10℃ during the addition. The reaction was carried out at room temperature for 4h.

[0120] (2) Pass dimethylamine gas (70.3 g, 1.56 mol) into the reaction flask, and control the temperature of the reaction system to be below -10℃ during the dropwise addition. React at room temperature for 4 h.

[0121] (2) Freshly collected cyclopentadiene (20.6 g, 0.31 mol) was slowly added dropwise to the reaction flask through a constant-pressure dropping funnel, keeping the temperature of the reaction system below 10 °C during the addition. After the addition of cyclopentadiene, the reaction was carried out at room temperature for 6 h under a N2 atmosphere. After the reaction was completed, the apparatus was replaced with an atmospheric distillation apparatus to remove n-hexane at 70 °C. Subsequently, the apparatus was replaced with a vacuum distillation apparatus, and the fraction at 100 °C / 0.4 mmHg was collected. Cyclopentadienyltris(dimethylamino)hafnium was not obtained.

[0122] Comparative Example 2

[0123] (1) Under N2 atmosphere, n-butyllithium (456.3 mL, 1.14 mol, 2.5 M n-hexane solution) was added to the reaction flask. Freshly collected cyclopentadiene (18.0 g, 0.27 mol) was slowly added to the reaction flask through a constant pressure dropping funnel. The temperature of the reaction system was controlled to be below -10℃ during the addition. The reaction was carried out at room temperature for 4 h.

[0124] (2) Hafnium tetrachloride (87g, 0.27mol) and 1L of n-hexane were added to a 5L reaction flask, the temperature was lowered to -20℃, and the temperature of the reaction system was controlled to be below -10℃ during the dropwise addition. The reaction was carried out at room temperature for 5h.

[0125] (3) Dimethylamine gas (70.3 g, 1.56 mol) was introduced into the reaction flask, and the temperature of the reaction system was controlled below -10 °C. The reaction was carried out at room temperature for 6 h under a N2 atmosphere. After the reaction was completed, the apparatus was replaced with an atmospheric distillation apparatus to remove n-hexane at 70 °C. Then the apparatus was replaced with a vacuum distillation apparatus, and the fraction at 100 °C / 0.4 mmHg was collected. Cyclopentadienyltris(dimethylamino)hafnium was not obtained.

[0126] Comparative Example 3

[0127] (1) Under N2 atmosphere, hafnium tetrachloride (113g, 0.35mol), freshly collected cyclopentadiene (23.3g, 0.35mol) and 1L of n-hexane were added to a 2.5L reaction flask, cooled to -20℃, and dimethylamine gas (79.5g, 1.76mol) was introduced into the reaction flask. The temperature of the reaction system was controlled to be below -10℃, and the reaction was carried out at room temperature for 8h.

[0128] (2) Butyllithium (592.7 mL, 1.48 mol, 2.5 M hexane solution) was slowly added dropwise to the reaction flask through a constant pressure dropping funnel, keeping the temperature of the reaction system below -10 °C during the addition. The reaction was carried out at room temperature for 6 h under a N2 atmosphere. After the reaction was completed, the apparatus was replaced with an atmospheric pressure distillation apparatus to remove hexane at 70 °C. Subsequently, the apparatus was replaced with a vacuum distillation apparatus, and the fraction at 100 °C / 0.4 mmHg was collected. Cyclopentadienyltris(dimethylamino)hafnium was not obtained.

[0129] Comparative Example 4

[0130] (1) Under N2 atmosphere, hafnium tetrachloride (91g, 0.28mol) and 1L of n-hexane were added to a 5L reaction flask and cooled to -20℃. Freshly collected cyclopentadiene (18.8g, 0.28mol) was slowly added to the reaction flask through a constant pressure dropping funnel. The temperature of the reaction system was controlled to be below -10℃ during the addition. After the cyclopentadiene was added, the reaction was carried out at room temperature for 6h under N2 atmosphere.

[0131] (2) Slowly add n-butyllithium (477.3 mL, 1.19 mol, 2.5 M n-hexane solution) dropwise into the reaction flask through a constant pressure dropping funnel, keeping the temperature of the reaction system below -10℃ during the addition, and react at room temperature for 4 h.

[0132] (3) Dimethylamine gas (64.0 g, 1.42 mol) was introduced into the reaction flask, and the temperature of the reaction system was controlled to be below -10 °C during the dropwise addition. The reaction was carried out at room temperature for 4 h. After the reaction was completed, the apparatus was replaced with an atmospheric distillation apparatus to remove n-hexane at 70 °C. Then the apparatus was replaced with a vacuum distillation apparatus, and the fraction at 100 °C / 0.4 mmHg was collected. Cyclopentadienyltris(dimethylamino)hafnium was not obtained.

[0133] Comparative Example 5

[0134] (1) Under N2 atmosphere, the collected fresh cyclopentadiene (20.6 g, 0.31 mol) and 1 L of n-hexane were added to a 5 L reaction flask, cooled to -20 °C, and dimethylamine gas (70.3 g, 1.56 mol) was introduced into the reaction flask. The temperature of the reaction system was controlled to be below -10 °C during the dropwise addition. The reaction was carried out at room temperature for 4 h.

[0135] (2) Cool down to -20℃, and slowly add n-butyllithium (524.5 mL, 1.31 mol, 2.5 M n-hexane solution) dropwise into the reaction flask through a constant pressure dropping funnel, controlling the temperature of the reaction system to be below -10℃ during the addition, and react at room temperature for 6 h;

[0136] (3) The temperature was lowered to -20℃, and hafnium tetrachloride (100g, 0.31mol) was added to the reaction flask. After the addition of hafnium tetrachloride, the reaction was carried out at room temperature for 6 hours under N2 atmosphere. After the reaction was completed, the apparatus was replaced with an atmospheric distillation apparatus to remove n-hexane at 70℃. Then the apparatus was replaced with a vacuum distillation apparatus, and the fraction at 100℃ / 0.4mmHg was collected. Cyclopentadienyltris(dimethylamino)hafnium was not obtained.

[0137] The yields of the products cyclopentadienyltris(dimethylamino)hafnium obtained in Examples 1-12 above are shown in Table 1.

[0138] Table 1

[0139]

[0140] In summary, this invention optimizes the existing method for preparing cyclopentadienyltris(dimethylamino)hafnium, simplifying the reaction steps and shortening the reaction time. Furthermore, no filtration is required after the reaction, and the resulting product exhibits high yield and purity, which is beneficial for large-scale industrial production.

[0141] The applicant declares that this invention illustrates the preparation method of cyclopentadienyltris(dimethylamino)hafnium through the above embodiments, but this invention is not limited to the above embodiments, that is, it does not mean that this invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials of this invention, addition of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

Claims

1. A method for preparing cyclopentadienyltris(dimethylamino)hafnium, characterized in that, The preparation method includes the following steps: (1) Mix hydrocarbon solvent, hafnium tetrachloride and dimethylamine, and add alkali metal compound to react; (2) Add cyclopentadiene to the reaction solution in step (1) and react to obtain the cyclopentadienyl tris(dimethylamino)hafnium; The alkali metal compound is n-butyllithium.

2. The preparation method according to claim 1, characterized in that, The hydrocarbon solvent in step (1) includes C5-C 12 Alkanes, C6-C 14 Aromatic hydrocarbons; Preferably, the hydrocarbon solvent in step (1) includes any one or a combination of at least two of n-pentane, n-hexane, n-heptane, benzene or toluene, preferably n-pentane, n-hexane or n-heptane, and more preferably n-hexane; Preferably, the mixing in step (1) is carried out under stirring.

3. The preparation method according to claim 1 or 2, characterized in that, The system is cooled before adding the n-butyllithium in step (1); Preferably, the cooling is to a temperature of -78℃ to -10℃.

4. The preparation method according to any one of claims 1-3, characterized in that, The method of adding n-butyllithium in step (1) is constant pressure dropwise addition; Preferably, the system temperature is controlled to be below -10°C during the addition of n-butyllithium in step (1).

5. The preparation method according to any one of claims 1-4, characterized in that, The molar ratio of n-butyllithium to hafnium tetrachloride in step (1) is (4-8):1, and more preferably (4-4.3):1; Preferably, the molar ratio of dimethylamine to alkali metal compound in step (1) is (1-1.8):1, more preferably (1-1.2):1; Preferably, the reaction temperature in step (1) is -78°C to room temperature, more preferably room temperature; Preferably, the reaction time in step (1) is 4 to 24 hours, more preferably 4 to 12 hours, and even more preferably 4 to 8 hours.

6. The preparation method according to any one of claims 1-5, characterized in that, The molar ratio of cyclopentadiene in step (2) to hafnium tetrachloride in step (1) is (1-4):1, and more preferably (1-1.1):

1.

7. The preparation method according to any one of claims 1-6, characterized in that, The cyclopentadiene was added to the system by constant pressure dropping. Preferably, the temperature of the reaction system is controlled to be below 10°C during the addition of cyclopentadiene in step (2).

8. The preparation method according to any one of claims 1-7, characterized in that, Both the reaction described in step (1) and the reaction described in step (2) are carried out under a protective gas atmosphere; Preferably, the protective gas includes any one or a combination of at least two of nitrogen, argon, or helium.

9. The preparation method according to any one of claims 1-8, characterized in that, After the reaction in step (2) is completed, the hydrocarbon solvent is first removed by atmospheric distillation, and then the fraction at 100℃ / 0.4mmHg is collected by vacuum distillation to obtain the cyclopentadienyltris(dimethylamino)hafnium.

10. The preparation method according to any one of claims 1-9, characterized in that, The preparation method of the cyclopentadienyltris(dimethylamino)hafnium specifically includes the following steps: (1) Under a protective gas atmosphere, a hydrocarbon solvent, hafnium tetrachloride and dimethylamine were mixed, cooled to -78℃~-10℃, and n-butyllithium was added dropwise under constant pressure. The reaction was carried out at room temperature for 4~24h. The hydrocarbon solvent includes C5-C. 12 Alkanes, C6-C 14 Aromatic hydrocarbons; the molar ratio of dimethylamine to hafnium tetrachloride is (4-8):1; the molar ratio of n-butyllithium to hafnium tetrachloride is (4-8):1; and the molar ratio of dimethylamine to alkali metal compound is (1-1.8):

1. (2) Add cyclopentadiene to the reaction solution in step (1), and control the temperature of the reaction system to be below 10°C. After the cyclopentadiene is added, the reaction system is reacted at room temperature for 4 to 18 hours under a protective gas atmosphere. After the reaction is completed, the hydrocarbon solvent is removed by atmospheric distillation, and then the fraction at 100°C / 0.4 mmHg is collected by vacuum distillation to obtain the cyclopentadienyl tris(dimethylamino)hafnium. The molar ratio of cyclopentadiene in step (2) to hafnium tetrachloride in step (1) is (1-4):1.

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