Anaerobic desolventizing and separating system

Abstract

The utility model relates to an anaerobic desolventizing and separating system, which comprises a first storage tank for storing a reaction solvent, and is characterized in that the output end of the first storage tank is connected with a synthesizer for solvent reaction; the output end of the synthesis device is connected with a first filtering device which is used for filtering insoluble substances after solvent reaction and obtaining a first reaction solution, the output end of the first filtering device is connected with a desolventizing assembly, and a positive pressure desolventizing device which is used for receiving the first reaction solution and providing a positive pressure environment is arranged in the desolventizing assembly. The system is suitable for synthesis and purification of metal chlorides with high reactivity.

Description

Technical Field

[0001] The utility model relates to an anaerobic desolvation and separation system. Background Art

[0002] There are numerous chemical reactions mediated by transition metal ions. For highly reactive transition metal compounds, their reactivity can pose certain problems in the reagent preparation process. Taking anhydrous chromium dichloride as an example, currently, the main preparation process of chromium dichloride is to introduce hydrogen chloride gas into a tube furnace to oxidize chromium powder to generate chromium dichloride, and then the unreacted chromium powder and the product chromium dichloride are separated by sedimentation. However, this process involves corrosive gases, and it is difficult to separate chromium powder from chromium dichloride, and there is likely to be residue, which affects the product quality.

[0003] Another method is to use anhydrous chromium(III) chloride as the raw material, and reduce it with hydrogen chloride and hydrogen to prepare chromium dichloride. However, this process not only uses strongly corrosive gases but also uses hydrogen, an explosive gas. Once corrosion and leakage occur, it is extremely likely to explode, with high danger.

[0004] In addition, there are also literature reports on the in-situ preparation method of chromium dichloride. Voltrova, S.,&Srogl, J. (2015) used DMF and THF as solvents, and zinc powder and manganese powder as reducing agents to reduce anhydrous chromium chloride to in-situ prepare a chromium dichloride solution as a catalyst. Other literature reports used acetonitrile as a solvent and synthesized a chromium dichloride solution by reacting anhydrous chromium trichloride with manganese. However, the above methods all obtain a mixture of chromium dichloride and metal chlorides, which are converted into other forms of complexes in the solution.

[0005] Those skilled in the art can foresee that if one wants to obtain a solid chromium dichloride product from the aforementioned chromium dichloride solution, the possible problems may include at least: First, chromium dichloride is easy to oxidize and deteriorate when exposed to air. Therefore, the product is likely to deteriorate during the desolvation and drying process of the chromium dichloride solution; Second, metal chlorides have good solubility in polar solvents. Therefore, direct desolvation cannot separate chromium dichloride from other chlorides, and the product purity is low. Summary of the Utility Model

[0006] The purpose of the utility model is to provide an anaerobic desolvation and separation system, which is applicable to the synthesis and purification of metal chlorides with high reactivity.

[0007] The technical solution of the present utility model lies in: an anaerobic desolvation and separation system, including a first storage tank for storing reaction solvents, characterized in that the output end of the first storage tank is connected to a synthesis device for carrying out solvent reactions, the output end of the synthesis device is connected to a first filtration device for filtering insolubles after the solvent reaction and obtaining a first reaction solution, the output end of the first filtration device is connected to a desolvation assembly, and a positive-pressure desolvation device for receiving the first reaction solution and providing a positive-pressure environment is provided in the desolvation assembly.

[0008] Further, the positive-pressure desolvation device is a desolvation kettle, an evaporator or a distillation column.

[0009] Further, a heating device for providing a high-temperature environment for the positive-pressure desolvation device is also provided.

[0010] Further, a condenser and a first solvent receiving tank for condensing and recovering the solvent after desolvation treatment are also provided in the desolvation assembly.

[0011] Further, it also includes a second storage tank and a second filtration device connected to the second storage tank. The second storage tank is used for storing separation solvents to separate target products from the recovered substances, and the second filtration device is connected to the output end of the positive-pressure desolvation device and receives the recovered substances.

[0012] Further, an inert gas supply system for providing inert gas to the synthesis device or the second filtration device is also included.

[0013] Further, the second filtration device is also connected to a second solvent receiving tank.

[0014] Further, an anaerobic drying device for carrying out anaerobic drying treatment on the separated target products is also included.

[0015] Further, the oxygen content inside the anaerobic drying device is lower than 10 ppm.

[0016] Compared with the prior art, the present utility model has the following advantages:

[0017] This system is applicable to the synthesis and purification of metal chlorides with high reactivity. By using zinc powder reduction and solid-liquid reaction to produce chromium dichloride, the use of dangerous gas raw materials can be avoided, and the process is safe. Description of the Drawings

[0018] Figure 1 It is a structural schematic diagram of the present utility model;

[0019] In the figure: 1 - First storage tank; 2 - Synthesis device; 3 - First filtration device; 4 - Second filtration device; 5 - Second solvent receiving tank; 6 - Positive pressure desolventizing device, 61 - Inlet, 62 - Outlet; 7 - Temperature control unit; 8 - Condenser; 9 - First solvent receiving tank; 10 - Second storage tank. Detailed implementation manners

[0020] To make the above features and advantages of the present utility model more understandable, specific embodiments are given below in conjunction with the accompanying drawings and described in detail as follows, but the present utility model is not limited thereto.

[0021] Figure 1 It is a schematic diagram of an anaerobic desolventizing and separation system in a specific embodiment of the present utility model, including a first storage tank 1 for storing reaction solvents. This patent is mainly applicable to solvent reactions. The output end of the first storage tank is connected to a synthesis device 2 for receiving reaction solvents and solid-phase reaction raw materials. The reaction raw materials are dissolved in the reaction solvents and undergo a synthesis reaction. The output end of the synthesis device is connected to a first filtration device 3. After the reaction is completed, the system is transferred to the first filtration device 3 for filtration to remove insoluble substances such as unreacted reaction raw materials and obtain a first reaction solution. The output end of the first filtration device is connected to a desolventizing assembly. The filtered first reaction solution is transferred into the desolventizing assembly to separate the reaction solvents in the synthesis device and obtain a mixture of target metal chlorides; the desolventizing assembly is connected to a second solvent receiving tank 5 through a second filtration device 4.

[0022] In a specific embodiment, the synthesis device 2 is a reaction kettle and is equipped with a stirrer. In a preferred embodiment, the synthesis device is connected to an inert gas supply system composed of a vacuum pump and a gas cylinder, etc., so that the inert gas supply system provides an inert gas atmosphere for the synthesis device. Combined with the desolventizing assembly, positive pressure distillation can be realized to avoid oxygen entering the reaction system during the desolventizing process.

[0023] In this embodiment, the desolventizing assembly includes a positive pressure desolventizing device 6 connected to the output end of the synthesis device for receiving the first reaction solution. The positive pressure desolventizing device can be a desolventizing kettle, an evaporator or a distillation column, etc., which is used to provide a positive pressure, inert gas atmosphere and high-temperature environment for the system to avoid oxidation of the solute during the desolventizing process. A heating device with a temperature control unit 7 for providing a high-temperature environment is arranged outside the positive pressure desolventizing device. The inlet 61 of the positive pressure desolventizing device is connected to the first solvent receiving tank 9 through a condenser 8 for condensing and recovering the distilled solvent; the outlet 62 of the positive pressure desolventizing device is connected to the input end of the second filtration device for transferring the desolventized product to the second filtration device.

[0024] In this embodiment, a second storage tank 10 is further included. The second storage tank is used to store a separation solvent for separating the target product from the recovered substances. The second storage tank is connected to the second filtering device through a pipeline, and the second filtering device is also connected to a second solvent receiving tank 5.

[0025] In this embodiment, the separation solvent used has different solubilities for the target product metal chloride and the impurity metal chloride. Therefore, after the synthesis and desolvation are completed, the impurity metal chloride is removed by washing the mixture of the target metal chloride, realizing the purification of the target metal chloride.

[0026] In this embodiment, the inert gas supply system can also provide an inert gas atmosphere for the second filtering device.

[0027] In this embodiment, an anaerobic drying device for drying the target metal chloride after washing and separation is further included. The oxygen content inside the anaerobic drying device is lower than 10 ppm.

[0028] This system is preferably used for synthesizing anhydrous chromium dichloride. The reaction raw materials, a trivalent chromium compound and a reaction solvent, are sent into the synthesis device for a synthesis reaction. Among them, the trivalent chromium compound is anhydrous chromium trichloride or anhydrous chromium trichloride tetrahydrofuran complex; the reaction solvent is a mixture of alcohol and tetrahydrofuran, where the alcohol can be methanol, ethanol, propanol, isopropanol, etc., and the ratio of alcohol to tetrahydrofuran is 1:0.5 - 1:2; the mass ratio of the reaction solvent to the trivalent chromium compound is 3:1 - 5:1. Nitrogen is filled into the reaction device through the inert gas supply system. Under stirring, a reducing agent is slowly added. After reacting for a period of time, the excess reducing agent is filtered off through the first filtering device to obtain a mixed solution of chromium dichloride and zinc chloride. The reducing agent used is zinc or manganese, preferably zinc powder, and the mesh number of the reducing agent is 100 - 200 mesh; the oxide content in the reducing agent is not higher than 5%, and the molar ratio of the reducing agent to the trivalent chromium compound is 1.5:1 - 3:1.

[0029] Subsequently, before the reaction solution is discharged into the positive pressure desolvation device, the positive pressure desolvation device is purged with nitrogen. The inert gas supply system provides a high-purity nitrogen atmosphere for the synthesis device to form a positive pressure condition, and the mixed solution is subjected to desolvation treatment. The desolvation pressure is 0.03 - 0.06 MPa (gauge pressure), and the desolvation temperature is 80 - 130 °C. A solid mixture is obtained after desolvation.

[0030] A separation solvent is added to the solid mixture for reflux washing. Using the second filtering device, the filtrate is filtered off, and the washing is repeated three times to obtain a crude chromium dichloride product. The separation solvent is an ether and a ketone, including diethyl ether, isopropyl ether, acetone, methyl ethyl ketone, etc. The mass ratio of the separation solvent to the solid is 2:1 - 4:1. This separation solvent has a high solubility for chromium dichloride, but has a high solubility for the main impurity chlorides, such as chromium chloride, etc., thereby separating out a high-purity product.

[0031] Finally, in an oxygen-free drying device, the washed target metal chloride is dried to obtain the product, gray anhydrous chromium dichloride.

[0032]

Example 1

[0033] Adopt the system as Figure 1 shown. The reaction solvent tetrahydrofuran is placed in the first storage tank, and other required containers are omitted. Add 1 kg of anhydrous chromium trichloride into the synthesis device, then add 1.5 eq of zinc powder, and then evacuate the synthesis device to -0.01 MPa and refill with high-purity nitrogen. Repeat the operation three times to ensure that the oxygen content in the kettle is qualified. Add 15 L of tetrahydrofuran into the synthesis device, and react at room temperature with stirring. Stir at room temperature until the purple solution becomes a gray suspension. Subsequently, the solvent removal assembly and the second filtration device are replaced with vacuum-high-purity nitrogen three times, and then the reaction solution is filtered through the first filtration device under positive pressure to remove unreacted zinc powder and a small amount of zinc chloride. The filtrate flows into the solvent removal assembly. Continue to add 0.04 MPa of nitrogen into the solvent removal assembly, and heat and remove the solvent under a nitrogen atmosphere. Heat until the temperature in the solvent removal kettle reaches 130 °C and maintain for a period of time until no condensate is collected. Then add 5 L of isopropyl ether into the solvent removal kettle, heat and stir under reflux for 3 h, cool to room temperature, drain into the second filtration device for filtration, and wash once with 2 L of isopropyl ether. Then blow dry with nitrogen for 2 h. Place the second filter in the glove box, open it to take out the gray chromium dichloride, and put it into the dryer in the glove box to dry, then the product can be obtained.

[0034]

Example 2

[0035] Adopt the system as Figure 1 shown. Take 1580 g of anhydrous chromium trichloride and add it to the reaction device, continue to add 1000 g of zinc powder, then carry out vacuum-high-purity nitrogen replacement, and then add 15 L of tetrahydrofuran and stir at room temperature for reaction. After the reaction is completed, drain the reaction solution into a positively pressurized solvent removal device that has been replaced with nitrogen for positive pressure solvent removal at a pressure of 0.03 MPa until the temperature inside the solvent removal reaches 120 °C. Then continue to add 6 L of acetone and reflux for 3 h, cool to room temperature and filter. The second filtration device is dried by purging with nitrogen, then taken out in the glove box and dried in the oven in the glove box to obtain 1044 g of gray solid, with a yield of 85% and a purity of 99%.

[0036]

Example 3

[0037] Adopt the system as Figure 1The system shown. Add 3750 g of chromium trichloride trihydrofuran (chromium content 12 - 14%) to the reaction device, then add 900 g of zinc powder, and then conduct vacuum-nitrogen replacement. Subsequently, add 15 L of tetrahydrofuran and react under stirring at room temperature. After the reaction ends, filter through the first filtration device. The filter cake is washed with 2 L of tetrahydrofuran continuously. The filtrate and the washing liquid are discharged into a positive pressure stripping device for positive pressure stripping. The stripping pressure is 0.035 MPa, and strip to 130 °C. After the stripping ends, add 3 L of methyl ethyl ketone and reflux for 3 h. Cool to room temperature and filter through the second filtration device. The second filtration device is purged and dried with nitrogen, and then placed in a glove box to take out the solid and dry it, obtaining 10.57 g of gray solid, with a yield of 86% and a purity of 99%.

[0038] If terms such as "first" and "second" are used in the text of the present utility model to limit components, those skilled in the art should be aware that: the use of "first" and "second" is only for the convenience of distinguishing components in the description. Unless otherwise stated, these terms have no special meaning.

[0039] If the present utility model discloses or involves components or structural members that are fixedly connected to each other, then, unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (for example, connected by bolts or screws), or it can also be understood as: a non-detachable fixed connection (for example, riveting, welding). Of course, the mutual fixed connection can also be replaced by an integral structure (for example, manufactured by integral forming using a casting process) (except when it is obvious that the integral forming process cannot be used).

[0040] In addition, unless otherwise stated, the terms used to represent the positional relationship or shape in any technical solution disclosed in the present utility model include states or shapes that are approximate, similar, or close to it.

[0041] Any component provided by the present utility model can either be assembled from multiple separate components or be a single component manufactured by an integral forming process.

[0042] The above are only the preferred embodiments of the present utility model. All equivalent changes and modifications made according to the scope of the patent application of the present utility model shall fall within the scope covered by the present utility model.

Claims

1. An anaerobic desolvation and separation system, including a first storage tank for storing reaction solvent, characterized in that, The output end of the first storage tank is connected to a synthesis device for solvent reaction. The output end of the synthesis device is connected to a first filtration device for filtering the insoluble substances after the solvent reaction and obtaining a first reaction solution. The output end of the first filtration device is connected to a desolventizing assembly, and a positive-pressure desolventizing device for receiving the first reaction solution and providing a positive-pressure environment is arranged in the desolventizing assembly.

2. The anaerobic desolvation and separation system according to claim 1, wherein The positive-pressure desolventizing device is a desolventizing kettle, an evaporator or a distillation column.

3. The anaerobic desolvation and separation system according to claim 1, wherein A heating device for providing a high-temperature environment for the positive-pressure desolventizing device is also provided.

4. The anaerobic desolvation and separation system according to claim 3, wherein, A condenser and a first solvent receiving tank for condensing and recovering the solvent after desolventizing treatment are also arranged in the desolventizing assembly.

5. The anaerobic stripping and separation system according to claim 1, characterized in that It further includes a second storage tank and a second filtration device connected to the second storage tank. The second storage tank is used for storing a separated solvent to separate the target product in the recovered material. The second filtration device is connected to the output end of the positive-pressure desolventizing device and receives the recovered material.

6. The anaerobic desolvation and separation system according to claim 1 or 5, characterized in that, It further includes an inert gas supply system for providing inert gas to the synthesis device or the second filtration device.

7. The anaerobic stripping and separation system according to claim 5, wherein The second filtration device is also connected to a second solvent receiving tank.

8. The anaerobic desolvation and separation system according to claim 5, wherein, It further includes an anaerobic drying device for performing anaerobic drying treatment on the separated target product.

9. The anaerobic stripping and separation system according to claim 8, wherein The oxygen content inside the anaerobic drying device is lower than 10 ppm.

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