Preparation method and device of molybdenum hexacarbonyl

Abstract

The invention belongs to the technical field of preparation of metal organic compounds, and particularly relates to a preparation method and device of molybdenum hexacarbonyl. The preparation method comprises the following steps: S1, introducing molybdenum powder and carbon monoxide into a reaction device, and carrying out catalytic reaction under the action of a catalyst to generate crude molybdenum hexacarbonyl; s2, cooling the crude molybdenum hexacarbonyl product to obtain liquid molybdenum hexacarbonyl; s3, carrying out reduced pressure distillation on the cooled liquid molybdenum hexacarbonyl; and S4, purifying the liquid molybdenum hexacarbonyl after reduced pressure distillation to obtain the final product molybdenum hexacarbonyl. The preparation device comprises a storage tank, a purifier, a reaction kettle, a condenser, a reduced pressure distillation tower and a recrystallization device which are sequentially arranged along the material flow direction. According to the method, the high-purity molybdenum is prepared through the reduction reaction of the carbon monoxide and the molybdenum powder at the high temperature, and the method has the advantages of being high in raw material purity, accurate in reaction temperature control, high in reaction efficiency and the like, and is particularly suitable for high-quality production of the molybdenum.

Description

Technical Field

[0001] This invention belongs to the field of organometallic compound preparation technology, specifically relating to a method and apparatus for preparing hexacarbonyl molybdenum. Background Technology

[0002] Molybdenum is an important industrial metal, widely used in nuclear reactor components, alloys, catalysts, and other fields. Traditional molybdenum preparation methods typically involve complex processes and high energy consumption, making it difficult to meet the industrial demand for high-purity molybdenum. In recent years, the reduction method for producing molybdenum has gained increasing attention because it can produce molybdenum by reducing molybdenum oxide (Mo2O5) with carbon monoxide, offering high production efficiency and environmental friendliness. However, existing reduction methods for producing high-purity molybdenum face certain technical bottlenecks, mainly in terms of raw material purity, reaction temperature control, and equipment efficiency. Hexacarbonylmolybdenum is an important organometallic compound whose unique chemical structure and properties make it promising for applications in numerous fields. Traditional hexacarbonylmolybdenum preparation methods have limitations that restrict its large-scale production and application.

[0003] Early methods for preparing molybdenum hexacarbonyl were primarily based on high-pressure reaction conditions, requiring extremely high pressure and temperature. This placed extremely high demands on the reaction equipment, increasing production costs and safety risks. For example, Chinese Patent CN120311038A discloses a method for preparing molybdenum hexacarbonyl powder under high-pressure circulation, using molybdenum raw materials and carbon monoxide to react in a synthesis reactor at 11.0-30.0 MPa to produce molybdenum hexacarbonyl and synthesis residues. Another example is Chinese Patent CN105967242B, which discloses a method for preparing nano-molybdenum hexacarbonyl powder, placing molybdenum raw materials in a high-pressure reactor, introducing CO gas into the reactor, and controlling the reaction pressure at 12-18 MPa. Some methods require reacting molybdenum with carbon monoxide at hundreds of atmospheres or even higher pressures. This high-pressure environment not only requires the reactor to have extremely high pressure resistance but also poses a potential explosion hazard during operation.

[0004] With the continuous development of technology, higher requirements have been placed on the quality and yield of molybdenum hexacarbonyl. Traditional methods not only require harsh reaction conditions but also have relatively low reaction efficiency and long reaction times, leading to extended production cycles and making it difficult to meet the growing market demand. Furthermore, controlling the purity of the product presents challenges, often requiring complex separation and purification steps to obtain high-purity molybdenum hexacarbonyl, further increasing production costs and process complexity. Therefore, with the continuous development of technology, higher requirements have been placed on the quality and yield of molybdenum hexacarbonyl.

[0005] Therefore, there is an urgent need to develop an efficient, safe, low-cost method and apparatus for producing high-purity molybdenum hexacarbonyl to solve the problems existing in the production of high-purity molybdenum hexacarbonyl in the current technology. Summary of the Invention

[0006] To address the problems of low efficiency and high cost in the preparation of molybdenum hexacarbonyl in the prior art, this application proposes a method and apparatus for preparing molybdenum hexacarbonyl.

[0007] The proposed solution is as follows: On the one hand, this application provides a method for preparing hexacarbonyl molybdenum, comprising the following steps: Step S1. Molybdenum powder and carbon monoxide are introduced into the reaction apparatus, and under the action of a catalyst, a catalytic reaction is carried out to produce crude hexacarbonyl molybdenum; The reaction is: Mo + 6CO → Mo(CO)6.

[0008] Step S2. Cool the crude hexacarbonylmolybdenum to obtain liquid hexacarbonylmolybdenum; Step S3. Perform vacuum distillation on the cooled liquid hexacarbonylmolybdenum; Step S4. Purify the liquid hexacarbonyl molybdenum after vacuum distillation to obtain the final product hexacarbonyl molybdenum.

[0009] Preferably, the purity of the molybdenum powder is greater than 99%, and the particle size of the molybdenum powder is 1-100 μm; the purity of the carbon monoxide is ≥99.5%, and the flow rate is 0.3~3 L / min; the molar ratio of molybdenum powder to carbon monoxide is 1:6~1:10.

[0010] More preferably, the purity of the molybdenum powder in step S1 is 99.2%~99.8%, and the particle size of the molybdenum powder is 20~80μm. The molybdenum powder with a suitable particle size has a large specific surface area, which is beneficial to fully contact with carbon monoxide gas and improve the reaction rate; the purity of the carbon monoxide is 99.6%~99.8%.

[0011] Preferably, in step S1, the temperature of the catalytic reaction is 100~300℃, the pressure is 1~10MPa, and the reaction time is 3~8h.

[0012] More preferably, the temperature of the catalytic reaction in step S1 is 150~250℃. Within this temperature range, the reaction rate can be guaranteed to be sufficient, while avoiding the increase of side reactions and energy waste caused by excessively high temperatures. The pressure is 3~7MPa. Within this pressure range, it is beneficial to maintain the concentration of carbon monoxide gas in the reaction system and promote the formation of molybdenum hexacarbonyl.

[0013] Preferably, the catalyst in step S1 is a metal halide, and the amount of catalyst added is 0.1% to 5% of the mass of molybdenum powder.

[0014] More preferably, the amount of catalyst added in step S1 is 1% to 3% of the mass of molybdenum powder.

[0015] Preferably, the metal halide is one or a mixture of two of molybdenum chloride or molybdenum bromide.

[0016] Preferably, the cooling temperature in step S2 is -20~20℃.

[0017] More preferably, the cooling temperature in step S2 is 0~10℃.

[0018] Preferably, the pressure of vacuum distillation in step S3 is 0.01~0.1MPa, and the temperature of vacuum distillation is 80~140℃.

[0019] More preferably, the pressure of vacuum distillation in step S3 is 0.03~0.07 MPa.

[0020] Preferably, the purification in step S4 is carried out by recrystallization, specifically by dissolving the liquid hexacarbonyl molybdenum distilled under reduced pressure in toluene or benzene, and then cooling it to -10°C at a rate of 0.5~1°C / min, causing the hexacarbonyl molybdenum to crystallize out, and filtering to obtain the final product hexacarbonyl molybdenum.

[0021] On the other hand, this application proposes an apparatus for preparing molybdenum hexacarbonyl, comprising, in sequence along the material flow direction, a storage tank for storing carbon monoxide, a purifier for purifying carbon monoxide, a reaction vessel for catalytic reaction, a condenser for condensing molybdenum hexacarbonyl, a vacuum distillation column for distilling liquid molybdenum hexacarbonyl, and a recrystallization device for purifying molybdenum hexacarbonyl; valves are provided on the pipelines connecting the storage tank, purifier, reaction vessel, condenser, vacuum distillation column, and recrystallization device; a flow meter is provided on the pipeline connecting the storage tank and the purifier, and a pipeline connecting the storage tank and the purifier is provided above the vacuum distillation column.

[0022] Preferably, the reactor is made of stainless steel, and the reactor is equipped with a magnetic stirring device and a jacketed heating and cooling device; the monoxide tower storage tank is a high-pressure steel cylinder; the purifier is filled with one or two types of activated carbon and molecular sieve adsorbent; the condenser is a tubular condenser structure, and the cooling medium is water or liquid nitrogen; the vacuum distillation tower is a packed tower structure, and the interior is filled with stainless steel wire mesh or ceramic Raschig ring packing; the recrystallization device includes a dissolving tank and a crystallizer.

[0023] More preferably, the adsorbent is a mixture of activated carbon and molecular sieve, the cooling medium of the condenser is water, and the vacuum distillation column is filled with stainless steel wire mesh.

[0024] Beneficial effects: (1) Improved reaction efficiency: By optimizing reaction conditions, including appropriate temperature, pressure and catalyst use, the preparation method of this application can significantly improve the reaction rate of molybdenum hexacarbonyl. Compared with traditional methods, the reaction time can be shortened by 30% to 50%, thereby improving production efficiency and reducing production costs.

[0025] (2) Improved product purity: The product processing procedure of this application includes multiple steps such as cooling, vacuum distillation and recrystallization, which can effectively remove impurities from the product and obtain high-purity hexacarbonylmolybdenum products. The product purity can reach more than 99%, which meets the purity requirements of high-end application fields for hexacarbonylmolybdenum; (3) Reduced safety risks: Although the reaction in this application is still carried out under certain pressure, compared with the traditional high pressure preparation method, the reaction pressure is controlled between 1 and 10 MPa, which significantly reduces the pressure resistance requirements of the reaction equipment, reduces safety risks, and improves the safety of the production process.

[0026] (4) Resource recycling: During the product processing, unreacted carbon monoxide gas can be recycled and reused through vacuum distillation, which reduces the consumption of raw materials, improves resource utilization, and further reduces production costs; Attached Figure Description

[0027] Figure 1 This is a diagram of the apparatus for preparing hexacarbonyl molybdenum according to this application.

[0028] Attached reference numerals: 1. Storage tank; 2. Flow meter; 3. Purifier; 4. Reactor; 5. Condenser; 6. Vacuum distillation column; 7. Recrystallization device. Detailed Implementation

[0029] To further illustrate the technical means and effects adopted by this application in order to achieve the intended purpose of the invention, the following detailed description of the specific implementation methods, structures, features and effects of this application is provided in conjunction with the accompanying drawings and preferred embodiments.

[0030] Device Examples like Figure 1 As shown, this embodiment provides an apparatus for preparing molybdenum hexacarbonyl, specifically as follows: it includes a storage tank 1 for storing carbon monoxide, a purifier 3 for purifying carbon monoxide, a reaction vessel 4 for catalytic reaction, a condenser 5 for condensing molybdenum hexacarbonyl, a vacuum distillation column 6 for distilling liquid molybdenum hexacarbonyl, and a recrystallization device 7 for purifying molybdenum hexacarbonyl, arranged sequentially along the material flow direction; valves are provided on the pipelines connecting the storage tank 1, purifier 3, reaction vessel 4, condenser 5, vacuum distillation column 6, and recrystallization device 7; a flow meter 2 is provided on the pipeline connecting the storage tank 1 and purifier 3; and a pipeline connecting the storage tank 1 and purifier 3 is located above the vacuum distillation column 6.

[0031] The reactor 4 is made of stainless steel. The reactor 4 is equipped with a magnetic stirring device and a jacketed heating and cooling device. The stirring speed of the magnetic stirring device can be adjusted between 100 and 1000 r / min, preferably between 300 and 800 r / min. The heating power of the heating and cooling device can be adjusted between 1 and 10 kW, and the cooling power can be adjusted between 0.5 and 5 kW, to control the temperature inside the reactor 4 between 100 and 300°C. Preferably, the heating power can be adjusted between 3 and 8 kW, and the cooling power can be adjusted between 1 and 4 kW.

[0032] Storage tank 1 is a high-pressure steel cylinder. The purifier 3 is filled with one or two types of adsorbents, namely activated carbon and molecular sieves. The preferred adsorbent is a mixture of activated carbon and molecular sieves. It is used to purify carbon monoxide to a purity of not less than 99.5%. Condenser 5 is a shell-and-tube condenser structure. This structure, by increasing the heat dissipation area and adjusting the flow rate, improves condensation efficiency. The cooling medium is water or liquid nitrogen, with water being preferred, which can rapidly cool the reaction product, molybdenum hexacarbonyl, to between -20°C and 20°C.

[0033] The vacuum distillation column 6 is a packed column structure, filled with stainless steel wire mesh or ceramic Raschig ring packing. The preferred packing is stainless steel wire mesh, which can separate unreacted carbon monoxide gas from liquid hexacarbonyl molybdenum under a pressure between 0.01 and 0.1 MPa.

[0034] The recrystallization apparatus 7 includes a dissolving tank and a crystallizer, used to dissolve liquid hexacarbonylmolybdenum in a suitable solvent and crystallize the hexacarbonylmolybdenum by slow cooling or evaporation of the solvent.

[0035] The apparatus operates as follows: Molybdenum powder is placed in reactor 4. Carbon monoxide is introduced from storage tank 1 through flow meter 2 and purifier 3 into reactor 4. Purifier 3 removes impurities from the carbon monoxide, such as carbon dioxide and hydrogen, which may react with the molybdenum powder, affecting the formation and purity of hexacarbonyl molybdenum. A magnetic stirrer and jacketed heating device are activated to catalyze the reaction and generate hexacarbonyl molybdenum. The generated hexacarbonyl molybdenum enters condenser 5 for rapid liquefaction. The liquid hexacarbonyl molybdenum enters vacuum distillation column 6 for distillation to separate and recover unreacted CO gas. The distilled liquid hexacarbonyl molybdenum is transferred to a dissolving tank and dissolved in benzene or toluene. The solution is then transferred to a crystallizer and slowly cooled to -10℃ at a rate of 0.5-1℃ / min to obtain Fe(CO)5 crystals.

[0036] Example 1 This embodiment provides a method for preparing hexacarbonyl molybdenum, based on the apparatus provided in the apparatus embodiment, including the following steps: Step S1. Molybdenum powder and carbon monoxide are introduced into the reaction apparatus. Under the action of a catalyst, the reaction produces crude molybdenum hexacarbonyl. The purity of the molybdenum powder is 99.5%, and the particle size of the molybdenum powder is 50~80μm. The purity of the carbon monoxide is 99.7%, and the flow rate is 2.5L / min. The temperature of the catalytic reaction is 200℃, and the pressure is 6MPa. The catalyst is molybdenum chloride, and the amount of catalyst added is 2.5% of the mass of the molybdenum powder.

[0037] Step S2. Cool the crude molybdenum hexacarbonyl to obtain liquid molybdenum hexacarbonyl at a cooling temperature of 5°C. Step S3. Perform vacuum distillation on the cooled liquid hexacarbonylmolybdenum at a pressure of 0.06 MPa; Step S4. Purify the liquid hexacarbonyl molybdenum after vacuum distillation to obtain the final product hexacarbonyl molybdenum. The purification is carried out by recrystallization. The specific operation is as follows: dissolve the liquid hexacarbonyl molybdenum after vacuum distillation in toluene or benzene, and then cool it to -10℃ at a rate of 0.7℃ / min, and hexacarbonyl molybdenum crystals out.

[0038] After testing, the yield of the hexacarbonylmolybdenum product was 85.4%, and the purity was 99.7%.

[0039] Example 2 This embodiment provides a method for preparing hexacarbonyl molybdenum, based on the apparatus provided in the apparatus embodiment, including the following steps: Step S1. Molybdenum powder and carbon monoxide are introduced into the reaction apparatus. Under the action of a catalyst, the reaction produces crude molybdenum hexacarbonyl. The purity of the molybdenum powder is 99.8%, and the particle size of the molybdenum powder is 1~20μm. The purity of the carbon monoxide is 99.5%, and the flow rate is 0.3L / min. The temperature of the catalytic reaction is 300℃, and the pressure is 1MPa. The catalyst is molybdenum chloride, and the amount of catalyst added is 0.1% of the mass of the molybdenum powder.

[0040] Step S2. Cool the crude molybdenum hexacarbonyl to obtain liquid molybdenum hexacarbonyl at a cooling temperature of -20℃. Step S3. Perform vacuum distillation on the cooled liquid hexacarbonylmolybdenum at a pressure of 0.1 MPa; Step S4. Purify the liquid hexacarbonyl molybdenum after vacuum distillation to obtain the final product hexacarbonyl molybdenum. The purification is carried out by recrystallization. The specific operation is as follows: dissolve the liquid hexacarbonyl molybdenum after vacuum distillation in toluene or benzene, and then cool it to -10℃ at a rate of 1℃ / min, and the hexacarbonyl molybdenum crystallizes out.

[0041] After testing, the yield of the hexacarbonyl molybdenum product was 86%, and the purity was 99.0%.

[0042] Example 3 This embodiment provides a method for preparing hexacarbonyl molybdenum, based on the apparatus provided in the apparatus embodiment, including the following steps: Step S1. Molybdenum powder and carbon monoxide are introduced into the reaction apparatus. Under the action of a catalyst, the reaction produces crude molybdenum hexacarbonyl. The purity of the molybdenum powder is 99.2%, and the particle size of the molybdenum powder is 80~100μm. The purity of the carbon monoxide is 99.8%, and the flow rate is 3L / min. The temperature of the catalytic reaction is 100℃, and the pressure is 10MPa. The catalyst is molybdenum bromide, and the amount of catalyst added is 5% of the mass of the molybdenum powder.

[0043] Step S2. Cool the crude molybdenum hexacarbonyl to obtain liquid molybdenum hexacarbonyl at a cooling temperature of 20°C. Step S3. Perform vacuum distillation on the cooled liquid hexacarbonylmolybdenum at a pressure of 0.01 MPa; Step S4. Purify the liquid hexacarbonyl molybdenum after vacuum distillation to obtain the final product hexacarbonyl molybdenum. The purification is carried out by recrystallization. The specific operation is as follows: dissolve the liquid hexacarbonyl molybdenum after vacuum distillation in toluene or benzene, and then cool it to -10℃ at a rate of 0.5℃ / min, and hexacarbonyl molybdenum crystals out.

[0044] After testing, the yield of the hexacarbonyl molybdenum product was 85.5%, and the purity was 99.2%.

[0045] Example 4 This embodiment provides a method for preparing hexacarbonyl molybdenum, based on the apparatus provided in the apparatus embodiment, including the following steps: Step S1. Molybdenum powder and carbon monoxide are introduced into the reaction apparatus. Under the action of a catalyst, the reaction produces crude molybdenum hexacarbonyl. The purity of the molybdenum powder is 99.7%, and the particle size of the molybdenum powder is 1-100 μm. The purity of the carbon monoxide is 99.8%, and the flow rate is 2.5 L / min. The temperature of the catalytic reaction is 200℃, and the pressure is 4 MPa. The catalyst is a mixture of molybdenum chloride and molybdenum bromide in a mass ratio of 1:2, and the amount of catalyst added is 3% of the mass of the molybdenum powder.

[0046] Step S2. Cool the crude molybdenum hexacarbonyl to obtain liquid molybdenum hexacarbonyl at a cooling temperature of 15°C. Step S3. Perform vacuum distillation on the cooled liquid hexacarbonylmolybdenum at a pressure of 0.04 MPa; Step S4. Purify the liquid hexacarbonyl molybdenum after vacuum distillation to obtain the final product hexacarbonyl molybdenum. The purification is carried out by recrystallization. The specific operation is as follows: dissolve the liquid hexacarbonyl molybdenum after vacuum distillation in toluene or benzene, and then cool it to -10℃ at a rate of 0.8℃ / min, and hexacarbonyl molybdenum crystals out.

[0047] After testing, the yield of the hexacarbonyl molybdenum product was 87%, and the purity was 99.6%.

[0048] Comparative Example 1 The difference between this comparative example and Example 1 is that the catalytic reaction pressure in this comparative example is 15 MPa, and the purity of the hexacarbonyl molybdenum obtained is 95.7%. Due to the excessively high reaction pressure, the reactants are more reactive, resulting in side reactions and an increase in impurities in the product, which are difficult to remove in subsequent distillation processes.

[0049] Comparative Example 2 The difference between this comparative example and Example 1 is that the catalytic reaction temperature in this comparative example is 400°C. The purity of the obtained hexacarbonyl molybdenum is 94.9%. Due to the increased temperature, more side reactions occurred.

[0050] The above description is merely a preferred embodiment of this application and is not intended to limit this application in any way. Although this application has been disclosed above with reference to preferred embodiments, it is not intended to limit this application. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of this application. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A method for preparing hexacarbonyl molybdenum, characterized in that, Includes the following steps: Step S1. Molybdenum powder and carbon monoxide are introduced into the reaction apparatus, and under the action of a catalyst, a catalytic reaction is carried out to produce crude hexacarbonyl molybdenum; Step S2. Cool the crude hexacarbonylmolybdenum to obtain liquid hexacarbonylmolybdenum; Step S3. Perform vacuum distillation on the cooled liquid hexacarbonylmolybdenum; Step S4. Purify the liquid hexacarbonyl molybdenum after vacuum distillation to obtain the final product hexacarbonyl molybdenum.

2. The method for preparing hexacarbonyl molybdenum according to claim 1, characterized in that, In step S1, the purity of the molybdenum powder is greater than 99%, and the particle size of the molybdenum powder is 1-100 μm; the purity of the carbon monoxide is ≥99.5%, and the flow rate is 0.3-3 L / min; the molar ratio of molybdenum powder to carbon monoxide is 1:6~1:

10.

3. The method for preparing hexacarbonyl molybdenum according to claim 1, characterized in that, In step S1, the temperature of the catalytic reaction is 100~300℃, the pressure is 1~10MPa, and the reaction time is 3~8h.

4. The method for preparing hexacarbonyl molybdenum according to claim 1, characterized in that, In step S1, the catalyst is a metal halide, and the amount of catalyst added is 0.1% to 5% of the mass of molybdenum powder.

5. The method for preparing hexacarbonyl molybdenum according to claim 4, characterized in that, The metal halide is one or a mixture of two of molybdenum chloride or molybdenum bromide.

6. The method for preparing hexacarbonyl molybdenum according to claim 1, characterized in that, The cooling temperature in step S2 is -20~20℃.

7. The method for preparing hexacarbonyl molybdenum according to claim 1, characterized in that, In step S3, the pressure of vacuum distillation is 0.01~0.1MPa, and the temperature of vacuum distillation is 80~140℃.

8. The method for preparing hexacarbonyl molybdenum according to claim 1, characterized in that, In step S4, the purification is carried out by recrystallization. Specifically, the liquid hexacarbonyl molybdenum distilled under reduced pressure is dissolved in toluene or benzene, and then cooled to -10°C at a rate of 0.5~1°C / min. The hexacarbonyl molybdenum crystallizes out and is filtered to obtain the final product, hexacarbonyl molybdenum.

9. An apparatus for preparing hexacarbonyl molybdenum, used in the method for preparing hexacarbonyl molybdenum according to any one of claims 1 to 8, characterized in that, The system includes a storage tank (1) for storing carbon monoxide, a purifier (3) for purifying carbon monoxide, a reaction vessel (4) for catalytic reaction, a condenser (5) for condensing molybdenum hexacarbonyl, a vacuum distillation column (6) for distilling liquid molybdenum hexacarbonyl, and a recrystallization device (7) for purifying molybdenum hexacarbonyl. Valves are provided on the pipelines connecting the storage tank (1), purifier (3), reaction vessel (4), condenser (5), vacuum distillation column (6) and recrystallization device (7). A flow meter (2) is provided on the pipeline connecting the storage tank (1) and purifier (3). A pipeline connecting the storage tank (1) and purifier (3) is provided above the vacuum distillation column (6).

10. The apparatus for preparing hexacarbonyl molybdenum according to claim 9, characterized in that, The reactor (4) is made of stainless steel and is equipped with a magnetic stirring device and a jacketed heating and cooling device inside. The storage tank (1) is a high-pressure steel cylinder. The purifier (3) is filled with one or two kinds of activated carbon and molecular sieve adsorbent. The condenser (5) is a tubular condensation structure and the cooling medium is water or liquid nitrogen. The vacuum distillation tower (6) is a packed tower structure and is filled with stainless steel wire mesh or ceramic Raschig ring packing. The recrystallization device (7) includes a dissolving tank and a crystallizer.

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