Preparation method of tris (methylcyclopentadienyl) yttrium

Abstract

The invention relates to the technical field of metal precursor synthesis, in particular to a preparation method of tris (methylcyclopentadienyl) yttrium. The preparation method of the tris (methylcyclopentadienyl) yttrium comprises the following steps: dropwise adding a methylcyclopentadiene monomer into yttrium hydride under the protection of inert gas at a certain temperature, reacting for a period of time, filtering, distilling, and finally purifying at absolute pressure to obtain the tris (methylcyclopentadienyl) yttrium, the steps are simple, the dangerousness of synthetic raw materials is small, a solvent does not need to be replaced in the synthetic process, no by-product is generated, and the method is suitable for industrial production. The subsequent purification steps are simple, kettle residues after the reaction are easy to treat, the treatment risk is small, and a simple, safe and efficient method is provided for synthesis of the tris (methylcyclopentadienyl) yttrium.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal precursor synthesis, and particularly relates to a preparation method of tris (methylcyclopentadienyl) yttrium. BACKGROUND

[0002] Yttrium is widely used in the manufacture of microwave magnetic materials, optical glass, ceramic material additives, high-brightness fluorescent powder for large-screen televisions and other display tube coatings, thin film capacitors and special refractory materials, and bubble materials for high-pressure mercury lamps, lasers, storage elements, etc.

[0003] The preparation method of tris (methylcyclopentadienyl) yttrium disclosed in the prior art is to react methylcyclopentadiene monomer with alkali metal or alkali metal hydride in tetrahydrofuran to prepare methylcyclopentadienyl sodium, then add yttrium chloride to react to obtain tris (methylcyclopentadienyl) yttrium tetrahydrofuran solution, add toluene after solvent evaporation, filter and evaporate to obtain tris (methylcyclopentadienyl) yttrium crude product, and then sublimate to obtain the finished product. The method has obvious defects. The excess alkali metal or alkali metal hydride is dangerous to handle, and the solvent tetrahydrofuran is introduced in the reaction. Sodium chloride is generated in the reaction process. The inorganic salt is in a suspended state in tetrahydrofuran and has a fine particle size. It is difficult to filter, two kinds of solvents need to be added in the preparation process, and the purification technology is difficult.

[0004] Therefore, the present application provides a new preparation method of tris (methylcyclopentadienyl) yttrium, which has simple synthesis steps and small risk of synthesis raw materials. No high-activity alkali metal or alkali metal hydride is needed in the synthesis process. No by-product is generated in the reaction. The post-reaction kettle residue is easy to handle and has small risk. SUMMARY

[0005] Therefore, the present application provides a new preparation method of tris (methylcyclopentadienyl) yttrium, which has simple synthesis steps and small risk of synthesis raw materials. No high-activity alkali metal or alkali metal hydride is needed in the synthesis process. No by-product is generated in the reaction. The post-reaction kettle residue is easy to handle and has small risk.

[0006] Based on the above purpose, the application provides a preparation method of tris (methylcyclopentadienyl) yttrium, comprising the following steps: (1) dissolving yttrium hydride in a solvent, passing liquid nitrogen through a liquid nitrogen coil for refrigeration, and adding methylcyclopentadiene stored at low temperature into the reaction system, and after the addition is completed, reacting at room temperature for 12-24 h; (2) removing the solvent by filtration and distillation to obtain tris (methylcyclopentadienyl) yttrium crude product; (3) sublimating tris (methylcyclopentadienyl) yttrium crude product at 100-200℃ under absolute pressure to obtain tris (methylcyclopentadienyl) yttrium; preferably, the solvent in step (1) is one of tetrahydrofuran, methyltetrahydrofuran, cyclopentane, cyclohexane, cycloheptane and toluene.

[0007] Preferably, the temperature of the refrigeration in step (1) is -20-20℃.

[0008] More preferably, the temperature of the refrigeration in step (1) is preferably 0-10℃.

[0009] Preferably, the molar ratio of yttrium hydride to methylcyclopentadiene in step (1) is 1:3-3.2.

[0010] Preferably, the low temperature of the methylcyclopentadiene stored at low temperature in step (1) is -30-0℃.

[0011] More preferably, the low temperature of the methylcyclopentadiene stored at low temperature in step (1) is -20-10℃.

[0012] More preferably, the temperature under absolute pressure in step (3) is 120-160℃.

[0013] The tris (methylcyclopentadienyl) yttrium synthesis method of the application has the advantages that the steps are simple, the synthesis raw materials have low danger, there is no highly active alkali metal or alkali metal hydride, no solvent needs to be replaced in the synthesis process, there is no by-product, the post-reaction kettle residue is easy to handle and has relatively low danger, and the subsequent purification steps are simple. BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description, Figure 1 The nuclear magnetic resonance hydrogen spectrum of tris (methylcyclopentadienyl) yttrium obtained in Example 2 of the application. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solutions and advantages of the application more clear and obvious, the following will further illustrate the application in combination with specific embodiments.

[0016] Example 1: A method for preparing tris (methylcyclopentadienyl) yttrium, the specific steps are as follows: (1) Under the inert gas atmosphere, 200 g of methylcyclopentadiene dimer was added to a 500 ml round bottom single neck flask, and the temperature was controlled at about -20 ℃ at 160 ℃ to obtain methylcyclopentadiene, which was stored for later use; (2) 36.8 g of yttrium hydride was dissolved in 500 ml of toluene, and after stirring uniformly, liquid nitrogen was introduced into the liquid nitrogen coil for refrigeration. When the temperature was 0 ℃, 98 g of methylcyclopentadiene (-10 ℃) was added dropwise into the reaction system. After the dropwise addition was completed, the reaction was carried out at room temperature for 12 h. After filtration and distillation of most of the solvent at 120 ℃, the crude product was obtained by vacuum drying. Finally, the finished product tris (methylcyclopentadienyl) yttrium was obtained by sublimation at absolute pressure and 120 ℃; (3) The finished product was detected by inductively coupled plasma emission spectrometer (ICP-OES), and the metal impurities were less than 1 ppm, and the purity reached 5N.

[0017] Example 2: A method for preparing tris (methylcyclopentadienyl) yttrium, the specific steps are as follows: (1) Under the inert gas atmosphere, 100 g of methylcyclopentadiene dimer was added to a 500 ml round bottom single neck flask, and the temperature was controlled at about -10 ℃ at 180 ℃ to obtain methylcyclopentadiene, which was stored for later use; (2) 18.4 g of yttrium hydride was dissolved in 30 ml of tetrahydrofuran, and after stirring uniformly, liquid nitrogen was introduced into the liquid nitrogen coil for refrigeration. When the temperature was 5 ℃, 48 g of methylcyclopentadiene (-5 ℃) was added dropwise into the reaction system. After the dropwise addition was completed, the reaction was carried out at room temperature for 16 h. After filtration and distillation of most of the solvent at 100 ℃, the crude product was obtained by vacuum drying. Finally, the finished product tris (methylcyclopentadienyl) yttrium was obtained by sublimation at absolute pressure and 140 ℃; (3) The finished product was detected by inductively coupled plasma emission spectrometer (ICP-OES), and the metal impurities were less than 1 ppm, and the purity reached 5N.

[0018] Example 3: A method for preparing tris (methylcyclopentadienyl) yttrium, the specific steps are as follows: (1) Under the inert gas atmosphere, 100 g of methylcyclopentadiene dimer was added to a 500 ml round bottom single neck flask, and the temperature was controlled at about -10 ℃ at 190 ℃ to obtain methylcyclopentadiene monomer, which was stored for later use; (2) 18.4 g of yttrium hydride is dissolved in 300 ml of cyclopentane, after stirring uniformly, liquid nitrogen is passed through a liquid nitrogen coil to cool, when the temperature is 10℃, 48.2 g of methylcyclopentadiene (0℃) is added dropwise into the reaction system, after the dropwise addition is completed, the reaction is carried out at room temperature for 24 h, filtration, distillation is carried out at 100℃, and finally sublimation is carried out at 160℃ under absolute pressure to obtain finished product tris(methylcyclopentadienyl) yttrium; (3) The finished product is detected by using an inductively coupled plasma optical emission spectrometer (ICP-OES), and the metal impurities are <1 ppm, and the purity reaches 5N.

[0019] It should be understood by those skilled in the art that the above discussion of any of the embodiments is merely exemplary and is not intended to suggest that the scope of the application is limited to these examples; under the idea of the application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the application as described above. In order to be brief, they are not provided in details.

Claims

1. A method for preparing tris(methylcyclopentadienyl)yttrium, characterized in that: The method comprises the following steps: (1) dissolving yttrium hydride in a solvent, introducing liquid nitrogen through a liquid nitrogen coil for refrigeration, and dropping methylcyclopentadiene stored at low temperature into the reaction system. After the dropwise addition is completed, the reaction is carried out at room temperature for 12 to 24 hours; (2) filtering and distilling to remove the solvent to obtain a crude tri(methylcyclopentadienyl)yttrium product; and (3) subliming the crude tri(methylcyclopentadienyl)yttrium product at 100 to 200° C. under absolute pressure to obtain tri(methylcyclopentadienyl)yttrium.

2. The method for preparing tris(methylcyclopentadienyl)yttrium according to claim 1, characterized in that: The solvent in step (1) is one of tetrahydrofuran, methyltetrahydrofuran, cyclopentane, cyclohexane, cycloheptane and toluene.

3. The method for preparing tris(methylcyclopentadienyl)yttrium according to claim 1, characterized in that: The refrigeration temperature in step (1) is -20~20℃.

4. The method for preparing tris(methylcyclopentadienyl)yttrium according to claim 1, characterized in that: The molar ratio of yttrium hydride to methylcyclopentadiene monomer in step (1) is 1:3~3.

2.

5. The method for preparing tris(methylcyclopentadienyl)yttrium according to claim 1, characterized in that: The low temperature of the methylcyclopentadiene under low temperature storage in step (1) is -30~0°C.

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