A process for the preparation of tris (methylcyclopentadienyl) yttrium

Abstract

The application relates to a preparation method of tris (methylcyclopentadienyl) yttrium, which comprises the following steps: S1, under a protective atmosphere, carrying out first heating reaction of yttrium chloride and sodium methylcyclopentadienyl in the presence of a first organic solvent, adding an organic ligand to carry out second heating reaction after sufficient reaction, and obtaining an intermediate product; the organic ligand is lithium di (trimethylsilyl) amide and / or potassium di (trimethylsilyl) amide; S2, carrying out stirring reaction of the intermediate product and methylcyclopentadiene in the presence of a second organic solvent, filtering to collect filtrate, and removing a solvent to obtain tris (methylcyclopentadienyl) yttrium. ‑ The application can effectively improve the substitution efficiency of chlorine in raw material yttrium chloride by introducing N(TMS)2 ‑ substituting chlorine in yttrium chloride which is not substituted by methylcyclopentadienyl, and then substituting methylcyclopentadiene to prepare tris (methylcyclopentadienyl) yttrium, so that the substitution efficiency of chlorine in the raw material yttrium chloride can be effectively improved, the yield of the target product can be greatly improved, can be as high as 86%, and the purity can reach 5N.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of organic chemistry and microelectronic material technology, in particular to a preparation method of tris (methylcyclopentadienyl) yttrium. BACKGROUND

[0002] Tris (methylcyclopentadienyl) yttrium (III) (hereinafter referred to as (MeCp) 3Y) is an important class of organo-rare earth metal complexes, which has a wide application prospect in the fields of olefin polymerization catalysts, organic synthesis reagents, and new material precursors. For example, as a precursor source material for deposition to prepare yttrium oxide, yttrium oxide is mainly used as a high-performance dielectric material, a diffusion barrier layer, and a packaging material in the microelectronic field, and is widely used in advanced integrated circuits, MEMS, optoelectronic devices, and other high-end technologies. These applications demonstrate the diversity and importance of yttrium oxide in modern science and industry, and with the development of material science and nanotechnology, the potential application fields of yttrium oxide are also expanding.

[0003] Currently, the conventional method for synthesizing (MeCp) 3Y in the field mainly borrows from the synthesis route of other rare earth metal metallocene compounds, that is, a double decomposition reaction is used. The traditional method usually uses anhydrous yttrium chloride (YCl3) and methylcyclopentadienyl sodium (MeCpNa) as raw materials to react in an inert organic solvent (such as toluene, tetrahydrofuran, etc.). The typical chemical reaction equation is as follows:

[0004] YCl3+ 3 MeCpNa → (MeCp) 3Y + 3 NaCl

[0005] Although this route is feasible in principle and is the standard method for preparing similar rare earth metal metallocene compounds in the laboratory, there are significant and urgent defects when it is actually applied to the preparation of (MeCp) 3Y. The most prominent problem is that the yield is generally low. This is because in the above synthesis method, the inherent low reaction efficiency, the difficulty of avoiding side reactions, and the large loss in post-processing problems result in a long-term low yield of (MeCp) 3Y (usually less than 60%), which greatly limits the large-scale preparation and practical application of the compound, and also increases its use cost.

[0006] Therefore, there is an urgent need for a preparation method that can obtain high yield and high purity (MeCp) 3Y to reduce the preparation cost of the compound and promote its more extensive application in different fields. SUMMARY

[0007] In order to solve the problem of low yield of (MeCp) 3Y prepared by the traditional synthesis method, the application provides a preparation method of tri (methylcyclopentadienyl) yttrium, wherein the chlorine atoms in yttrium chloride are partially replaced by methylcyclopentadienyl, then a specific organic ligand is introduced to replace the chlorine atoms in yttrium chloride which are not replaced by methylcyclopentadienyl to obtain an intermediate product, and then the intermediate product is replaced by methylcyclopentadiene to prepare tri (methylcyclopentadienyl) yttrium. By the above method of introducing the intermediate product, the substitution efficiency of chlorine in the raw material yttrium chloride can be effectively improved, thereby greatly improving the yield of the target product, which can be as high as 86%, and the purity can reach 5N.

[0008] Specifically, the following technical solutions are provided:

[0009] The first aspect of the application provides a preparation method of tri (methylcyclopentadienyl) yttrium, comprising the following steps:

[0010] S1, yttrium chloride and sodium methylcyclopentadienyl are subjected to a first heating reaction in the presence of a first organic solvent, and then an organic ligand is added for a second heating reaction after sufficient reaction to obtain an intermediate product;

[0011] The organic ligand is lithium bis (trimethylsilyl) amide (LiN(TMS) 2) and / or potassium bis (trimethylsilyl) amide (KN(TMS) 2) ;

[0012] S2, the intermediate product is directly subjected to a stirring reaction with methylcyclopentadiene, or is subjected to a stirring reaction in the presence of a second organic solvent, and then the filtrate is collected after sufficient reaction and filtration, and the solvent is removed to obtain the tri (methylcyclopentadienyl) yttrium.

[0013] The application is accidentally discovered by the inventor in the process of optimizing the synthesis method of tri (methylcyclopentadienyl) yttrium. After the chlorine atoms in yttrium chloride are partially replaced by methylcyclopentadienyl, a specific organic ligand, lithium bis (trimethylsilyl) amide and / or potassium bis (trimethylsilyl) amide, is introduced to replace the chlorine atoms in yttrium chloride which are not replaced by methylcyclopentadienyl, and then methylcyclopentadiene is added to replace lithium bis (trimethylsilyl) amide to prepare tri (methylcyclopentadienyl) yttrium, which can effectively improve the yield of the target product. The order of replacing sodium methylcyclopentadienyl and adding the organic ligand, or directly using a sufficient amount of the above organic ligand to fully react with yttrium chloride, and then reacting with methylcyclopentadiene to prepare the target product, will greatly reduce the yield of the target product. In addition, using other organic ligands such as lithium dimethylamide and lithium diethylamide to replace the above specific organic ligand cannot obtain the target product.

[0014] Further, the protective atmosphere includes but is not limited to nitrogen.

[0015] Further, in step S1, the molar ratio of the yttrium chloride to the sodium methylcyclopentadienyl and the organic ligand is preferably 1: (2-2.4): 1, such as 1:2:1, 1:2.1:1, 1:2.2:1, 1:2.3:1, 1:2.4:1, and the like, including but not limited to the above-listed molar ratios.

[0016] In the present application, the molar ratio of the yttrium chloride to the sodium methylcyclopentadienyl affects the yield of the product. If the molar ratio of the sodium methylcyclopentadienyl to the yttrium chloride is less than 2, there is not enough ligand to combine with the yttrium chloride, which reduces the yield of the product. It has been found that, within the above-mentioned preferred range, if the amount of the sodium methylcyclopentadienyl is reduced and the amount of the organic ligand is increased, the yield is greatly reduced. If the amount of the sodium methylcyclopentadienyl is too much, such as if the ratio of the two is greater than 2.4, it affects the purification of the product and reduces the yield. At the same time, when the molar ratio of the yttrium chloride to the sodium methylcyclopentadienyl is 1: (2-2.4), the amount of the organic ligand also cannot be too much. Too much organic ligand produces by-products, which is not conducive to the purification of the product.

[0017] Under the above-mentioned molar ratio conditions, the chemical reaction equation involved in the preparation method is as follows:

[0018] YCl3+ 2 MeCpNa→ YCl (MeCp)2+ 2 NaCl;

[0019] YCl (MeCp)2+ KN (TMS)2→ Y (MeCp)2[N (TMS)2]+ KCl;

[0020] Y (MeCp)2[N (TMS)2]+ MeCpH→ Y (MeCp)3+ HN (TMS)2.

[0021] Further, in step S1, the first organic solvent is selected from one or more of toluene, tetrahydrofuran, n-hexane, and more preferably toluene.

[0022] Further, in step S1, the temperature of the first heating reaction is 60-100 ℃, such as 60 ℃, 70 ℃, 80 ℃, 90 ℃, 100 ℃, and the like, and the reaction time is not less than 4 h, such as 6 h, and the like.

[0023] Further, in step S1, the temperature of the second heating reaction is 60-100 ℃, such as 60 ℃, 70 ℃, 80 ℃, 90 ℃, 100 ℃, and the like, and the reaction time is not less than 1 h, such as 1 h, 2 h, and the like.

[0024] Further, after the second heating reaction in step S1, methylcyclopentadiene can be directly added to the mixed solution containing the intermediate product for stirring reaction, or the filtrate can be separated by filtration, and the intermediate product can be obtained by removing the solvent, and then the intermediate product and methylcyclopentadiene can be stirred in the presence of the second organic solvent.

[0025] Further, the molar ratio of the organic ligand to the methylcyclopentadiene is preferably 1: (1-2) to sufficiently replace the N(TMS)2 group in the intermediate product and improve the yield of the target product. - However, if too much is added, the methylcyclopentadiene is prone to dimerization, which may cause some side reactions with the product, thereby reducing the yield.

[0026] Further, in step S2, the second organic solvent is selected from one or more of toluene, tetrahydrofuran, and n-hexane.

[0027] Further, in step S2, the temperature of the stirring reaction is preferably -20-80 ℃, and the reaction time is not less than 1 h, for example, 1 h at 80 ℃.

[0028] Further, the preparation method further comprises a sublimation step of the tris (methylcyclopentadienyl) yttrium obtained by removing the solvent in step S2, to obtain tris (methylcyclopentadienyl) yttrium with a purity of 5 N.

[0029] Further, the sublimation is performed at 155-185 ℃ and 1 Torr.

[0030] Compared with the prior art, the present application has the following beneficial effects:

[0031] The present application provides a preparation method of tris (methylcyclopentadienyl) yttrium. After the chlorine atoms in yttrium chloride are partially replaced by methylcyclopentadienyl groups, specific organic ligands lithium di (trimethylsilyl) amide and / or potassium di (trimethylsilyl) amide are introduced to replace the chlorine atoms in yttrium chloride that are not replaced by methylcyclopentadienyl groups to prepare an intermediate product, and then methylcyclopentadiene is added to replace the di (trimethylsilyl) amide to prepare tris (methylcyclopentadienyl) yttrium. This can effectively improve the yield of the target product (not less than 70%), even up to 86%, and the purity of the product can reach 5 N, meeting the purity requirements of yttrium oxide precursor source materials in the microelectronic field. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a structural diagram of tris (methylcyclopentadienyl) yttrium;

[0033] Figure 2 is a nuclear magnetic hydrogen spectrum of tris (methylcyclopentadienyl) yttrium prepared in Example 1. DETAILED DESCRIPTION

[0034] The present application will be further described with reference to the drawings and specific examples, so that those skilled in the art can better understand the present application and implement it, but the examples are not intended to limit the present application.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing specific embodiments only and is not intended to be limiting of the application. The use herein of "including", "comprising" or "having" also covers the case of "consisting of" or "consisting" of.

[0036] Example 1: This example relates to a method for preparing tris(methylcyclopentadienyl) yttrium, which is carried out as follows:

[0037] Into a reaction flask, under nitrogen protection, was transferred freshly prepared YCl3(0.2 mol, 39.1 g) and sodium methylcyclopentadienide (0.4 mol, 40.8 g). Toluene was added at room temperature, 500 mL. After heating at 80 °C for 6 hours, KN(TMS)2 solution in toluene (0.2 mol, 40.0 g) was added. After stirring at this temperature for 1 hour, freshly depolymerized methylcyclopentadiene (0.2 mol, 16.1 g) was added. After stirring at this temperature for 1 hour, filtration was performed. The filtrate was removed from the solvent, and the product was obtained by sublimation at 180 °C and 1 Torr vacuum. The product was a light yellow solid (0.164 mol, 53.5 g), with a yield of 82%. The hydrogen spectrum was as shown in Figure 2 ICP test showed that the purity of the product was 5N.

[0038] Example 2: This example relates to a method for preparing tris(methylcyclopentadienyl) yttrium, which is carried out as follows:

[0039] Into a reaction flask, under nitrogen protection, was transferred freshly prepared YCl3(0.2 mol, 39.1 g) and sodium methylcyclopentadienide (0.4 mol, 40.8 g). Toluene was added at room temperature, 500 mL. After heating at 80 °C for 6 hours, LiN(TMS)2 solution in toluene (0.2 mol, 33.5 g) was added. After stirring at this temperature for 1 hour, freshly depolymerized methylcyclopentadiene (0.2 mol, 16.1 g) was added. After stirring at this temperature for 1 hour, filtration was performed. The filtrate was removed from the solvent, and the product was obtained by sublimation at 180 °C and 1 Torr vacuum. The product was a light yellow solid (0.158 mol, 51.5 g), with a yield of 79%. The product was confirmed to be tris(methylcyclopentadienyl) yttrium by nuclear magnetic resonance. ICP test showed that the purity of the product was 5N.

[0040] Example 3: This example relates to a method for preparing tris(methylcyclopentadienyl) yttrium, which is carried out as follows:

[0041] (1) Into a reaction flask, YCl3(0.2 mol, 39.1 g) and freshly prepared sodium methylcyclopentadienide (0.4 mol, 40.8 g) were transferred under nitrogen protection. Toluene 500 mL was added at room temperature. After heating at 80 °C for 6 hours, KN(TMS)2 solution in toluene (0.2 mol, 40.0 g) was added. After stirring at this temperature for 1 hour, the reaction was filtered, and the filtrate was removed to obtain an intermediate product.

[0042] (2) The intermediate product was dissolved in toluene at room temperature, and freshly depolymerized methylcyclopentadiene (0.2 mol, 16.1 g) was added. After stirring at 80 °C for 1 hour, the product was obtained by sublimation at 180 °C and 1 Torr vacuum. The product was a light yellow solid (0.172 mol, 56.1 g) with a yield of 86%, which was confirmed by nuclear magnetic resonance to be the target product tris(methylcyclopentadienyl) yttrium. The product purity was 5N by ICP test.

[0043] Example 4: This example relates to a method for preparing tris(methylcyclopentadienyl) yttrium, which is different from example 3 only in that in step (2), the intermediate product was dissolved in a large amount of freshly depolymerized methylcyclopentadiene (0.8 mol, 64.1 g) at room temperature, and the reaction was stirred at room temperature for 1 hour.

[0044] The rest of the operations were consistent, and a light yellow solid (0.162 mol, 52.9 g) was obtained with a yield of 81%, which was confirmed by nuclear magnetic resonance to be the target product tris(methylcyclopentadienyl) yttrium. The product purity was 5N by ICP test.

[0045] Example 5: This example relates to a method for preparing tris(methylcyclopentadienyl) yttrium, which is different from example 3 only in that in step (2), an equal volume of tetrahydrofuran was used instead of toluene.

[0046] The rest of the operations were consistent, and a light yellow solid (0.142 mol, 46.3 g) was obtained with a yield of 71%, which was confirmed by nuclear magnetic resonance to be the target product tris(methylcyclopentadienyl) yttrium. The product purity was 5N by ICP test.

[0047] Example 6: This example relates to a method for preparing tris(methylcyclopentadienyl) yttrium, which is different from example 3 only in that in step (1), the amount of sodium methylcyclopentadienide added was 0.48 mol.

[0048] The remaining operations are consistent, and a light yellow solid (0.162 mol, 52.9 g) is obtained, with a yield of 81%, which is confirmed by nuclear magnetic resonance as the target product tris (methylcyclopentadienyl) yttrium. The product purity is 5N by ICP test.

[0049] Comparative Example 1: This comparative example relates to a preparation method of tris (methylcyclopentadienyl) yttrium, and the specific operation is as follows:

[0050] Under nitrogen protection, the freshly prepared YCl3 (0.2 mol, 39.1 g) and methylcyclopentadienyl sodium (0.6 mol, 61.2 g) are transferred into the reaction bottle, 500 mL of toluene is added at room temperature, and heated at 80 ℃ for 8 hours. After filtration, the filtrate is removed from the solvent, and the product is obtained by sublimation at 180 ℃ and 1 Torr vacuum, which is a light yellow solid (0.118 mol, 38.5 g) with a yield of 59%, which is confirmed by nuclear magnetic resonance as the target product tris (methylcyclopentadienyl) yttrium. The product purity is 5N by ICP test.

[0051] Comparative Example 2: This comparative example relates to a preparation method of tris (methylcyclopentadienyl) yttrium, which is different from Example 1 in that YCl3 and three equivalents of KN(TMS)2 are first completely reacted, and then methylcyclopentadiene is added for reaction, and the specific operation is as follows:

[0052] Under nitrogen protection, the freshly prepared YCl3 (0.2 mol, 39.1 g) and methylcyclopentadienyl sodium (0.6 mol, 61.2 g) are transferred into the reaction bottle, 500 mL of toluene is added at room temperature, and heated at 80 ℃ for 8 hours. After filtration, the filtrate is removed from the solvent, and the product is obtained by sublimation at 180 ℃ and 1 Torr vacuum, which is a light yellow solid (0.118 mol, 38.5 g) with a yield of 59%, which is confirmed by nuclear magnetic resonance as the target product tris (methylcyclopentadienyl) yttrium. The product purity is 5N by ICP test.

[0053] Compared with Example 3, the yield of the target product is significantly reduced, which is speculated to be due to the fact that the ligand steric hindrance is too large and the basicity is too strong, making it difficult to form Y[N(TMS)2]3 intermediate, and the unreacted KN(TMS)2 and methylcyclopentadiene react to form methylcyclopentadienyl potassium, which reacts with the remaining chlorine on yttrium chloride, with very low substitution efficiency.

[0054] Comparative Example 3: This comparative example relates to a preparation method of tris (methylcyclopentadienyl) yttrium, which is different from Example 1 in that the addition order of methylcyclopentadienyl sodium and KN(TMS)2 is replaced, and the specific operation is as follows:

[0055] Into a reaction flask was placed freshly prepared YCl3(0.2 mol, 39.1 g) and toluene 500 mL under nitrogen protection, KN(TMS)2 in toluene solution (0.2 mol, 40.0 g) was added, after heating at 80 ℃ for 1 hour, sodium methylcyclopentadienyl (0.4 mol, 40.8 g) was added, after heating at 80 ℃ for 6 hours, freshly depolymerized methylcyclopentadiene (0.4 mol, 32.1 g) was added, after stirring at this temperature for 1 hour, filtration was performed, the filtrate was removed from the solvent, and the product was obtained by sublimation at 180 ℃ and 1 Torr vacuum, which was a light yellow solid (0.064 mol, 20.9 g), the yield was 32%, and the target product tris(methylcyclopentadienyl) yttrium was confirmed by nuclear magnetic resonance. The product purity was 5N by ICP testing.

[0056] Comparative Example 4: The present comparative example relates to a preparation method of tris(methylcyclopentadienyl) yttrium, which is different from Example 1 in that equimolar lithium dimethylamide is used to replace KN(TMS)2, and the rest of the operations are consistent, and the target product is not obtained.

[0057] Comparative Example 5: The present comparative example relates to a preparation method of tris(methylcyclopentadienyl) yttrium, which is different from Example 1 in that equimolar lithium diethylamide is used to replace KN(TMS)2, and the rest of the operations are consistent, and the target product is not obtained.

[0058] The above-described examples are only preferred examples for fully illustrating the present application, and the protection scope of the present application is not limited thereto. Any equivalent replacement or transformation made by a person skilled in the art on the basis of the present application is within the protection scope of the present application. The protection scope of the present application is subject to the claims.

Claims

1. A method for preparing tris(methylcyclopentadienyl)yttrium, characterized in that, Includes the following steps: Under a protective atmosphere, S1. Yttrium chloride and sodium methylcyclopentadienyl chloride are subjected to a first heating reaction in the presence of a first organic solvent. After the reaction is complete, an organic ligand is added and a second heating reaction is carried out to obtain an intermediate product. The organic ligand is lithium bis(trimethylsilyl)amino and / or potassium bis(trimethylsilyl)amino; the molar ratio of yttrium chloride to sodium methylcyclopentadienyl and the organic ligand is 1:(2-2.4):1; the first organic solvent is selected from one or more of toluene, tetrahydrofuran, and n-hexane; S2. The intermediate product is directly reacted with methylcyclopentadiene by stirring, or reacted by stirring in the presence of a second organic solvent. After the reaction is complete, the filtrate is collected by filtration and the solvent is removed to obtain the tris(methylcyclopentadienyl)yttrium. The second organic solvent is selected from one or more of toluene, tetrahydrofuran, and n-hexane. The molar ratio of the organic ligand to the methylcyclopentadiene is 1:(1-2).

2. The preparation method according to claim 1, characterized in that, In step S1, the temperature of the first heating reaction is 60-100 ℃, and the reaction time is not less than 4 h.

3. The preparation method according to claim 1, characterized in that, In step S1, the temperature of the second heating reaction is 60-100 ℃, and the reaction time is not less than 1 h.

4. The preparation method according to claim 1, characterized in that, In step S2, the temperature of the stirring reaction is -20~80 ℃, and the reaction time is not less than 1 h.

5. The preparation method according to claim 1, characterized in that, The preparation method further includes a step of sublimating the tris(methylcyclopentadienyl)yttrium obtained by removing the solvent in step S2 to obtain tris(methylcyclopentadienyl)yttrium with a purity of 5 N.

6. The preparation method according to claim 5, characterized in that, The sublimation was carried out at 155-185 °C and 1 Torr.

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