Preparation method of electronic-grade hexa-carbon-based tungsten

Abstract

The invention discloses a preparation method of electronic-grade six-carbon-based tungsten, which comprises the following steps of: removing high-boiling-point substances by adopting a sublimation method, collecting highly purified raw materials in a vacuum environment, and further removing impurities by adopting a specific decompression sublimation condensation method to finally obtain the electronic-grade six-carbon-based tungsten of which the purity is not lower than 7N grade. The method has the characteristics of high efficiency, simplicity, convenience, lower cost and capability of adapting to large-scale industrial production.

Description

[0001] The present invention relates to a high-purity semiconductor dopant, and particularly to a preparation method of electronic-grade tungsten hexacarbonyl. Background Art

[0002] Tungsten hexacarbonyl is a colorless, odorless, volatile solid with the molecular formula W(CO) 6 , with a density of 2.65 g / cm 3 . The melting point is 172 - 174 °C. The sublimation temperature is 50 °C. It is soluble in dry ether, 2-methoxy dry ether, hexane, etc. It sublimes in a vacuum. W(CO) 6 is a colorless or white diamagnetic solid with an octahedral structure, which is very stable to air, water and acids, but will be decomposed by strong alkali solutions. It is insoluble in water but soluble in many organic solvents. It decomposes at about 150 °C.

[0003] In summary, this material is easy to sublime, easy to be decomposed and denatured by strong alkali solutions, and easy to dissolve in most organic solvents, resulting in the difficulty of separating this material from many low-boiling organic compounds by conventional physical and chemical methods. Therefore, the existing preparation methods have the following problems: 1. High energy consumption; 2. Mainly purified by fine instruments such as quartz multi-neck flasks, which is only applicable to laboratories and not suitable for large-scale production; 3. Unstable quality; there is no preparation method with low cost and suitable for large-scale industrial production.

[0004] In the current prior art, there is no related technology to solve the above problems. At present, a preparation method of electronic-grade tungsten hexacarbonyl that is efficient, simple, low-cost and suitable for large-scale industrial production is needed. Summary of the Invention

[0005] The present invention aims to provide a preparation method of electronic-grade tungsten hexacarbonyl that is efficient, simple, low-cost and suitable for large-scale industrial production.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A preparation method of electronic-grade tungsten hexacarbonyl, the preparation method includes the following stages: S1: Raw material preparation ① Raw material preparation: Prepare sufficient tungsten hexacarbonyl with a mass purity of not less than 99.5% and dry ether; ② Tooling and equipment preparation: Prepare a quartz sublimation tower, a vacuum chamber with a vacuum degree of 1×10 -4 Pa - 10 Pa, and a quartz encapsulation container; S2: Pretreatment ① Place the tungsten hexacarbonyl prepared in step ① of S1 in the vacuum chamber prepared in step ① of stage S1, heat it to 55 °C - 65 °C, and after the quality is stable, maintain the vacuum degree, collect the sublimation gas and condense it to obtain preliminarily purified tungsten hexacarbonyl; ② Add the initially purified tungsten hexacarbonyl obtained in step ① into the vacuum chamber prepared in step ② of stage S1, and drop the dry diethyl ether prepared in step ① of S1 until the initially purified tungsten hexacarbonyl is just completely dissolved in the dry diethyl ether. Then, control the system temperature to drop to -2°C to 2°C to crystallize the initially purified tungsten hexacarbonyl dissolved in the dry diethyl ether. Filter out the crystals and obtain the secondarily purified tungsten hexacarbonyl after drying.

[0007] S3: Sublimation ① Use the quartz sublimation tower prepared in step ② of stage S1 to sublime the secondarily purified tungsten hexacarbonyl obtained in step ② of S2. The sublimation process parameters are: maintain the vacuum degree in the quartz sublimation tower at 1×10 -1 Pa to 100 Pa, heat to 50°C to 100°C, collect the volatilized vapor, and the vapor is condensed by a condenser to obtain tungsten hexacarbonyl with removed heavy impurities; repeat this step until a product with a mass purity of not less than 99.9999% is qualified; before sublimation, use vacuum and inert gas to displace the gas in the sublimation system, and ensure that the system is in a slightly positive pressure state after displacement to prevent ambient air from entering the system and affecting sublimation. After sublimation, obtain sublimated tungsten hexacarbonyl; S4: Detection ① Detect the sublimated tungsten hexacarbonyl obtained in step ① of stage S3. It is required that the impurity content is not higher than 0.000001%, the moisture content is not more than 0.5 ppm, and the mass purity of the sublimated tungsten hexacarbonyl is not less than 99.9999% to obtain the target sublimated tungsten hexacarbonyl; S5: Encapsulation ① Encapsulate the sublimated tungsten hexacarbonyl qualified in step ① of stage S4 in the vacuum chamber prepared in step ② of stage S1 using the quartz encapsulation container prepared in step ② of stage S1. After encapsulation and sealing, obtain the required electronic-grade tungsten hexacarbonyl.

[0008] Compared with the prior art, due to the adoption of the above technical solutions, the present invention has the following advantages: (1) In the present invention, physical pre-purification is carried out first. High-boiling substances are removed by sublimation method, and sublimation gas with the main component being the target product is collected by sublimation in a fixed temperature range. This method can remove high-melting-point substances by high-temperature sublimation under vacuum conditions, and at the same time prevent the target product from hydrolyzing when encountering water. High-purity products can be obtained only through pretreatment.

[0009] (2) The specific vacuum distillation method of the present invention not only effectively solves the interference of foreign impurities, but also realizes a purification technology with low energy consumption, high efficiency and good effect, enabling the present invention to achieve the best combination of three-dimensional parameters of economy, product technical effect and suitability for large-scale industrial production.

[0010] Therefore, the present invention has the characteristics of high efficiency, simplicity, low cost and adaptability to large-scale industrial production. Specific Embodiments Example 1

[0011] A preparation method of electronic-grade tungsten hexacarbonyl, the preparation method comprising the following stages: S1: Raw material preparation ① Raw material preparation: Prepare sufficient tungsten hexacarbonyl with a mass purity of not less than 99.5% and dry ether; ② Tooling and equipment preparation: Prepare a quartz sublimation tower, a vacuum chamber with a vacuum degree of 1×10 -4 Pa~10 Pa, and a quartz encapsulation container; S2: Pretreatment ① Place the tungsten hexacarbonyl prepared in step ① of S1 in the vacuum chamber prepared in step ① of S1, heat it to 55°C~65°C, and after the quality is stable, maintain the vacuum degree, collect the sublimated gas and condense it to obtain initially purified tungsten hexacarbonyl; ② Drop the initially purified tungsten hexacarbonyl obtained in step ① into the vacuum chamber prepared in step ② of S1, and add the dry ether prepared in step ① of S1 until the initially purified tungsten hexacarbonyl is just completely dissolved in the dry ether. Then control the system temperature to drop to -2°C~2°C to crystallize the initially purified tungsten hexacarbonyl dissolved in the dry ether, filter out the crystals, and obtain secondary purified tungsten hexacarbonyl after drying.

[0012] S3: Sublimation ① Use the quartz sublimation tower prepared in step ② of S1 to sublime the secondary purified tungsten hexacarbonyl obtained in step ② of S2. The sublimation process parameters are: maintain the vacuum degree in the quartz sublimation tower at 1×10 -1 Pa~100 Pa, heat to 50°C~100°C, collect the volatilized vapor, and the vapor is condensed by a condenser to obtain de-weighted and impurity-removed tungsten hexacarbonyl; repeat this step until a product with a mass purity of not less than 99.9999% is qualified; before sublimation, use vacuum and inert gas to replace the gas in the sublimation system, and ensure that the system is in a slightly positive pressure state after replacement to ensure that ambient air will not enter the system and affect sublimation. After sublimation, obtain sublimated tungsten hexacarbonyl; S4: Detection ① Detect the sublimated tungsten hexacarbonyl obtained in step ① of S3, requiring that the impurity content is not higher than 0.000001%, the moisture content is not more than 0.5 ppm, and the mass purity of the sublimated tungsten hexacarbonyl is not less than 99.9999% to obtain the target sublimated tungsten hexacarbonyl; S5: Encapsulation ① Encapsulate the sublimated tungsten hexacarbonyl qualified in step ① of S4 in the vacuum chamber prepared in step ② of S1 using the quartz encapsulation container prepared in step ② of S1. After encapsulation and sealing, obtain the required electronic-grade tungsten hexacarbonyl.

[0013] The electronic-grade tungsten hexacarbonyl obtained according to this embodiment has the characteristics of high efficiency, simplicity, low cost and adaptability to large-scale industrial production.

[0014] The above description of the disclosed embodiments is only to enable those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing electronic grade hexacarbon-based tungsten, characterized in that: The preparation method The following phases are included: S1: Raw material preparation ① Raw material preparation: prepare sufficient tungsten hexacarbonyl with a purity of not less than 99.5% and dry ether; ② Preparation of tools and equipment: prepare quartz sublimation tower, vacuum degree 1×10 -4 Pa~10Pa vacuum chamber, quartz packaging container; S2: Preprocessing ① Place the hexacarbonyl tungsten prepared in step ① of S1 into the vacuum chamber prepared in step ① of stage S1, heat it to 55°C~65°C, maintain the vacuum degree after the mass is stable, collect and condense the sublimated gas, and obtain the initially purified hexacarbonyl tungsten; ② Place the initially purified hexacarbonyl tungsten obtained in step ① in the vacuum chamber prepared in step ② of stage S1, and drop the dry ether prepared in step ① of S1 until the initially purified hexacarbonyl tungsten is just completely dissolved in the dry ether, then control the system temperature to drop to -2°C~2°C to allow the initially purified hexacarbonyl tungsten dissolved in the dry ether to crystallize, filter out the crystals, and dry to obtain the secondary purified hexacarbonyl tungsten; S3: Sublimation ① Use the quartz sublimation tower prepared in step ② of stage S1 to sublime the secondary purified tungsten hexacarbonyl obtained in step ② of S2. The sublimation process parameters are: maintain the vacuum degree in the quartz sublimation tower at 1×10 -1 Pa~100Pa, heated to 50℃~100℃, collected the volatilized steam, condensed the steam through a condenser to obtain the de-weighted hexacarbonyl tungsten; repeated this step until the product with a mass purity of not less than 99.9999% is qualified; before sublimation, the sublimation system is replaced with a vacuum and inert atmosphere, and after the replacement, the system is kept in a slightly positive pressure state to ensure that the ambient air does not enter the system and affect the sublimation, and the sublimated hexacarbonyl tungsten is obtained after sublimation; S4: Detection ① Testing the sublimated tungsten hexacarbonyl obtained in step ① of stage S3, requiring the impurity content to be no higher than 0.000001%, the water content to be no greater than 0.5 ppm, and the mass purity of the sublimated tungsten hexacarbonyl to be no less than 99.9999%, to obtain the target sublimated tungsten hexacarbonyl; S5: Encapsulation ① The sublimed hexacarbonyl tungsten that has passed the inspection in step ① of stage S4 is packaged in the vacuum chamber prepared in step ② of stage S1 using the quartz packaging container prepared in step ② of stage S1. After the packaging is completed and sealed, the required electronic grade hexacarbonyl tungsten is obtained.