A solvent drying device and method for drying organic solvents using a potassium-sodium alloy and which can be used repeatedly

Abstract

The application discloses a kind of solvent drying device and method for drying organic solvent with potassium-sodium alloy and being recycled multiple uses, the solvent water and oxygen removal device includes, the reaction bottle of distillation is carried out and the collection bottle is arranged above reaction bottle, the upper end of reaction bottle is communicated with the upper end of collection bottle by distillation neck, and liquid nitrogen cold trap for cooling is arranged on distillation neck;Second high vacuum gate is opened in collection bottle, first high vacuum gate is opened in reaction bottle, the pressure in bottle can be adjusted by first high vacuum gate and second high vacuum gate, and then solvent, metal is put in and taken out under the protection of inert gas;Stirring son is arranged in reaction bottle.The application can satisfy extremely sensitive chemical reaction system, does not need to master glass firing process, reduces the threshold of experiment of conventional potassium-sodium alloy drying solvent method, and can be recycled multiple times, avoid the security risk generated by residual metal after drying each time in the method of common potassium-sodium alloy drying solvent.

Description

Technical Field

[0001] This invention belongs to the field of solvent purification technology, specifically relating to a solvent drying method using a potassium-sodium alloy to dry organic solvents, which can be recycled multiple times. Background Technology

[0002] In chemical synthesis, it is often necessary for the reactants and products to be sensitive to air, meaning they are unstable to water and oxygen in the air. Therefore, it is necessary to dehydrate and deoxygenate the organic solvents. This is especially true for some particularly sensitive reaction systems, such as carbanion / carbocation reactions, carbene / carbabe reactions, organometallic reagents, organometallic catalysts, rare earth complexes, and multi-radical reactions, where the requirement for anhydrous and oxygen-free solvents is even higher. To avoid surface passivation or deactivation of alkali metals, strong oxidants, and other active initiators during reactions, the water and oxygen content (ppm) of the organic solvent is usually required to be less than 0.1 (ppm means parts per million).

[0003] Currently, there are four main methods for dehydrating and deoxygenating organic solvents in the laboratory: 1. Molecular sieve-assisted double-row tube high-vacuum line operation: the organic solvent is first dehydrated using activated molecular sieves, and then the dehydrated organic solvent is repeatedly evacuated and purged with inert gas using liquid nitrogen on a double-row tube high-vacuum line; 2. Solvent purification device: commercially available solvent purification devices are used, which achieve purification through filtration columns; 3. Sodium metal and benzophenone (indicator) reflux method: sodium metal and benzophenone are added together to the organic solvent, and then refluxed for a long time using a common distillation apparatus; 4. Potassium-sodium alloy drying: organic solvents are dried using a potassium-sodium alloy, and then transferred by distillation using a common distillation transfer apparatus; or a self-made integrated glass tool is used for reaction and transfer.

[0004] However, each of the above methods has its own limitations: the organic solvent obtained by drying using method 1 has a high oxygen content and can only be applied to general anhydrous and oxygen-free reaction systems. It is not suitable for some sensitive reactions, such as the reduction reaction of nano-carbon, the preparation of rare earth complexes and organometallic complexes, and the stabilization of multiple free radicals; the solvent purification equipment described in method 2 is generally expensive, costing hundreds of thousands of yuan, and there is a short period of contact with air after collection. Furthermore, the use of a filtration column for purification can result in trace amounts of metal ions in the anhydrous and oxygen-free organic solvent, thus reducing the success rate of the reaction; method 3 often requires heating and reflux for tens of hours. If not monitored, prolonged heating and reflux under the heating mantle can easily pose safety hazards and cause serious consequences. The consequences are numerous. Furthermore, this method is carried out under inert gas protection, and the solvent distillation often requires a temperature far exceeding the solvent's boiling point, making it unsuitable for some strongly coordinated and high-boiling-point organic solvents, such as diethylene glycol dimethyl ether (boiling point 159.76°C). While method 4 uses potassium-sodium alloy for excellent drying, common distillation and transfer devices are not integrated but rather assembled using vacuum silicone grease. This leads to a decline in the quality of the anhydrous and oxygen-free solvent during distillation and transfer, making it unsuitable for extremely sensitive reaction systems. Using a self-made integrated glass tool for reaction and transfer requires re-firing the glass after each use, and neither of these methods can be recycled. The large amount of residual potassium-sodium alloy after each use requires quenching, which is extremely dangerous. Therefore, a solvent drying device and method using potassium-sodium alloy for drying organic solvents that can be recycled multiple times is needed. Summary of the Invention

[0005] Due to the aforementioned deficiencies in existing technologies, this invention provides a solvent drying apparatus and method for drying organic solvents using a potassium-sodium alloy that can be recycled multiple times. It features an integrated glass system, low operational requirements, low cost, and excellent sealing performance. The potassium-sodium alloy can be used for purification with good results, meeting the needs of sensitive reaction systems. It can be reused multiple times, thus eliminating the need for frequent treatment of large amounts of residual potassium-sodium alloy, making it safer. Furthermore, because the system pressure is adjustable, purification can be performed under negative pressure. The required operating temperature is far below the boiling point of the solvent, enabling the drying of some strongly coordinated and high-boiling-point organic solvents, such as diethylene glycol dimethyl ether (boiling point 159.76°C). This invention provides a solvent drying apparatus and method for drying organic solvents using a potassium-sodium alloy, which is recyclable and produces high-quality anhydrous and oxygen-free solvents suitable for extremely sensitive chemical reaction systems. It also features low operational requirements, minimal heating requirements, and reduced safety risks. The apparatus is highly efficient, economical, recyclable, and safe, and can meet the needs of extremely sensitive chemical reaction systems (such as carbanions / carbocations, carbene / carbabe, organometallic reagents, organometallic catalysts, rare earth complexes, and multiple free radicals). It does not require mastery of glassmaking processes, has low operational requirements, and avoids the safety hazards associated with conventional potassium-sodium alloy methods for drying organic solvents.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a solvent drying apparatus for drying organic solvents using a potassium-sodium alloy that can be recycled multiple times, comprising an integrally formed glass purification device and a high-vacuum gate; the glass purification device includes a reaction flask for distillation and a collection flask disposed above the reaction flask, the upper end of the collection flask being connected to the reaction flask via a distillation neck, and a liquid nitrogen cold trap for cooling being disposed between the distillation neck and the collection flask; a connecting pipe is disposed between the collection flask and the reaction flask, the connecting pipe connecting the collection flask and the reaction flask; the high-vacuum gate includes a first high-vacuum gate disposed on the connecting pipe and a second high-vacuum gate disposed on the collection flask; the first high-vacuum gate can control the connecting pipe by closing or partially opening a valve core, thereby selectively controlling the connection between the collection flask and the reaction flask; the second high-vacuum gate is provided with an evacuation port; the reaction flask contains a potassium-sodium alloy and a stir bar.

[0007] Using the above technical solution, the recyclable solvent dehydration and deoxygenation device provided by this invention has an integrated glass structure, resulting in better vacuum sealing. It can rapidly dehydrate and deoxygenate various organic solvents using potassium-sodium alloy. It dries quickly at room temperature, avoiding safety hazards associated with prolonged heating. After one distillation of the organic solvent, the remaining solvent can be stored in the reaction flask. When the solvent or potassium-sodium alloy is used up, it can be directly added, achieving reuse. Therefore, there is no need to process the potassium-sodium alloy after each use, avoiding safety hazards. Furthermore, the pressure inside the reaction flask can be adjusted using a high-vacuum valve, and the operating temperature is far below the boiling point of the solvent, making it even safer. Unused solvent in the collection bottle can be returned to the reaction flask through the connecting pipe, avoiding solvent waste and making it more economical.

[0008] In some embodiments, the liquid nitrogen cold trap includes a hollow condenser cup and a liquid nitrogen pool formed by the recess of the condenser cup; the interior of the condenser cup is connected to the distillation neck and the collection bottle respectively, and the liquid nitrogen pool can store liquid nitrogen.

[0009] With this design, liquid nitrogen can be directly added to the liquid nitrogen pool, which is convenient. The liquid nitrogen pool is surrounded by the condenser cup, and the liquid nitrogen can cool the gas inside the condenser cup. The structure is simple, the contact surface is large during the cooling process, and the cooling effect is good.

[0010] In some embodiments, the high vacuum gates are all high vacuum Schlenk-type glass gates with plug threads fully covered by PTFE, and the first and second high vacuum gates can be used for material entry and exit under inert gas conditions.

[0011] The air extraction port can be connected to a double-row pipe, and with the cooperation of the double-row pipe, the internal air pressure of the device can be adjusted under inert gas. The stir bar is a glass-enclosed magnetic stir bar.

[0012] The dual-row tubes are used to provide an inert environment and vacuum conditions.

[0013] In some embodiments, for safety reasons, the wall thickness of all glass equipment used must be greater than or equal to 1 mm; the reaction flask is a round-bottom flask with a volume of 150 mL to 2000 mL; the collection flask is a round-bottom flask with a volume not greater than half the volume of the reaction flask; the shortest distance between the distillation neck and the collection flask is greater than 1 cm; the shortest distance between the liquid nitrogen cold trap and the collection flask is greater than 1 cm; and the glass thickness at the liquid nitrogen cold trap is not less than 1 mm.

[0014] This design is intended to meet the overall strength requirements.

[0015] Secondly, the present invention also provides a solvent drying method using a potassium-sodium alloy to dry organic solvents, which can be recycled multiple times, comprising the following steps:

[0016] S1. After baking the entire solvent dehydration and deoxygenation device in an oven, use a double-row pipe to repeatedly evacuate and fill with inert gas three times through the air extraction port to create an anhydrous and oxygen-free internal environment. Then, the stir bar, potassium-sodium alloy and organic solvent are introduced into the reaction flask through the first high-vacuum gate. During this period, it is always necessary to maintain a slight positive pressure inside the device.

[0017] In some embodiments, the stir bar and potassium-sodium alloy are introduced into the reaction flask through the first high-vacuum gate in the glove box. Then, after repeatedly evacuating and filling with inert gas three times using a double-row tube, the required organic solvent is introduced into the reaction flask through the first high-vacuum gate.

[0018] S2. Stir the organic solvent in the reaction flask using the stir bar.

[0019] S3. After repeatedly depressurizing the device on the double-row tube at least twice through the second high-vacuum gate, pour liquid nitrogen into the liquid nitrogen cold trap, and then repeat the depressurization at least twice.

[0020] S4. The reaction flask is baked so that the organic solvent is distilled, condensed in a liquid nitrogen trap, and stored in the collection flask.

[0021] S5. The treated organic solvent is extracted through the second high-vacuum gate under inert gas protection. During this process, the device is kept under a slight positive pressure.

[0022] S6. After use, the second high-vacuum valve can be opened to recover the unused remaining organic solvent in the collection bottle into the reaction bottle.

[0023] In some embodiments, to meet the requirements of sensitive reaction systems, in step S1, the solvent dehydration and deoxygenation device is baked at a temperature of 80°C or above for 30 minutes or more to remove residual moisture from the glass surface. To ensure an anhydrous and oxygen-free environment for the system, the vacuum level during the repeated vacuuming must be reduced to below 100 mbar on the vacuum gauge, and each decompression must be performed to reduce the vacuum level to 600 mbar or below. Simultaneously, to prevent oxygen from entering during material flow, the inert gas flow rate into the device must be maintained at no less than 70 ml / min to ensure the pressure of the glass device remains positive at all times. The aforementioned inert gas refers to a chemically inert and relatively stable gas, including but not limited to helium, nitrogen, and argon with a purity of no less than 99.999%. For reactions involving alkali metals, argon is typically used as the inert gas for safety and cost considerations, and high-purity argon with a purity of no less than 99.999% is required. For safety, in step S4, the baking temperature should be greater than or equal to the boiling point of the organic solvent, but less than 500°C, to prevent the glass from melting.

[0024] Compared with the prior art, the above invention has the following advantages or beneficial effects: the potassium-sodium alloy drying method for organic solvents can be recycled and reused multiple times, which can meet the needs of extremely sensitive chemical reaction systems (such as carbanion / carbocation, carbene / carbabe, organometallic reagents, organometallic catalysts, rare earth complexes, multi-radicals, etc.), does not require mastery of glass firing technology, has low operation requirements, avoids the safety hazards of conventional potassium-sodium alloy drying methods for organic solvents, and is inexpensive, thus having great application and commercial value in the field of organic solvent purification. Attached Figure Description

[0025] The invention, its features, shape, and advantages will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings. Like reference numerals denote like parts throughout the drawings. The drawings are not drawn to scale; their focus is on illustrating the gist of the invention.

[0026] Figure 1 A schematic diagram of a recyclable solvent dehydration and deoxygenation device provided in an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the second high-vacuum gate provided in an embodiment of the present invention.

[0028] Among them, 1. reaction flask; 1-1. first high vacuum gate; 2. collection flask; 2-1. second high vacuum gate; 3. distillation neck; 4. liquid nitrogen cold trap; 4-1. condenser cup; 4-2. liquid nitrogen pool; 5. stir bar; 6. connecting pipe; 7. evacuation port. Detailed Implementation

[0029] The structure of the present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention.

[0030] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In the description of this invention, it should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature.

[0032] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0033] Example

[0034] Please see Figure 1 This embodiment provides a solvent drying device for drying organic solvents using a potassium-sodium alloy that can be recycled multiple times. The device includes an integrally formed glass purification unit and a high-vacuum valve. The glass purification unit includes a reaction flask 1 for distillation and a collection flask 2 positioned above the reaction flask 1. The upper end of the collection flask 2 is connected to the upper end of the reaction flask 1 via a distillation neck 3. A liquid nitrogen cold trap 4 for cooling is provided between the distillation neck 3 and the collection flask 2. A connecting pipe 6 connects the collection flask 2 and the reaction flask 1. The high-vacuum valve includes a first high-vacuum valve 1-1 located in the connecting pipe and a second high-vacuum valve 2-1 located in the collection flask. The first high-vacuum valve 1-1 can be used to close or open the connection between the collection flask 2 and the reaction flask 1 via a valve core. The reaction flask 1 contains a potassium-sodium alloy and a stir bar 5.

[0035] It is worth noting that existing distillation and condensation devices are not integrated; multiple glasswares are assembled when needed, and silicone grease is used at the joints to prevent air ingress. Solvents dried using this system can only be used for general anhydrous and oxygen-free reactions, and cannot be used for some particularly sensitive reaction systems, such as carbanion / carbocation reactions, carbene / carbabe reactions, organometallic reagents, organometallic catalysts, rare earth complexes, and multi-radical reactions. Although some advanced laboratories abroad have mastered the glass-firing process and use self-made sintered integrated glass transfer systems to dry solvents with potassium-sodium alloys, this requires re-firing the glass after each use, and the large amount of residual potassium-sodium alloy after each use needs to be quenched, which is extremely dangerous.

[0036] This invention not only utilizes a one-piece molded glass system, providing superior sealing performance, but also allows for the safe use of potassium-sodium alloys for dehydration and deoxygenation, meeting the needs of sensitive chemical systems. Furthermore, compared to methods using metallic sodium as a drying solvent, it dries rapidly at room temperature, eliminating the need for prolonged heating and avoiding safety hazards associated with extended heating periods. Moreover, it is reusable, requiring no post-use treatment of the potassium-sodium alloy, thus enhancing safety.

[0037] Existing distillation and condensation devices often suffer from insufficient airtightness, requiring a continuous flow of inert gas into the system, which is wasteful of inert gas. Furthermore, under positive pressure, liquid nitrogen cooling cannot be used; only water condensation is possible, increasing the difficulty of distillation. Combined with the positive pressure environment, high-boiling-point solvents are virtually impossible to distill. In this embodiment, the entire solvent dehydration and deoxygenation device has excellent sealing properties. Air can be extracted through a high-vacuum valve, creating a negative pressure environment inside the device. This lowers the solvent's melting point, making high-boiling-point solvents easier to distill. Moreover, since the solvent used for purification already has high purity, the reaction flask does not accumulate significant amounts of impurities and only requires periodic cleaning.

[0038] Specifically, sodium-potassium alloy and stir bar 5 can be added to reaction flask 1 through first high vacuum gate 1-1 and connecting pipe 6, and purified organic solvent can be extracted from second high vacuum gate 2-1 set in collection flask 2 through syringe.

[0039] It should be noted that the water content in this embodiment is measured by a Karl Fischer apparatus, that is, approximately 3.0 mL of sample (the exact amount added was determined by weighing the filled syringe and the empty syringe after the sample was injected into the cells on a three-decimal-place balance inside the glove box and calculating the difference) is injected into the anode chamber of the measuring cell of the Karl Fischer apparatus (N=6).

[0040] Existing laboratory glass solvent purification technologies typically use sodium as a desiccant, resulting in a residual water content (ppm) of approximately 43.4 and a residual oxygen content (ppm) of approximately 32.5. This method requires prolonged high-temperature reflux, leading to poor safety; it also necessitates the use of grease-sealed glass, resulting in poor airtightness; and its purification effect is not as good as that of potassium-sodium alloys. Furthermore, commercial solvent purification systems use molecular sieves, activated aluminum, and activated copper as desiccants, achieving a residual water content (ppm) of approximately 1 and a residual oxygen content (ppm) of approximately 1. However, these devices are expensive, costing hundreds of thousands of dollars, and the purification columns are disposable and require maintenance. Filtration purification introduces trace amounts of metal ions, contaminating the solvent.

[0041] The recyclable solvent dehydration and deoxygenation device disclosed in this application uses a potassium-sodium alloy to rapidly dehydrate and deoxygenate various organic solvents. The treatment is carried out in an integrated glass device, and high-quality anhydrous and oxygen-free organic solvents can be obtained after treatment, with a water and oxygen content of less than 0.1 ppm. This solvent dehydration and deoxygenation equipment is simple to operate, low in cost, highly efficient, has adjustable pressure, and can be recycled. It avoids the safety problems caused by prolonged heating and frequent handling of residual potassium-sodium alloys, as well as the problem of impurity generation caused by prolonged drying or heating.

[0042] In some embodiments, the liquid nitrogen cold trap 4 includes a hollow condenser cup 4-1 and a liquid nitrogen pool 4-2 formed by the recess of the condenser cup 4-1. The interior of the condenser cup 4-1 is connected to the distillation neck 3 and the collection bottle 2, respectively. The liquid nitrogen pool 4-2 stores liquid nitrogen and cools the condenser cup 4-1. This design and the shape of the liquid nitrogen pool make it easier to add liquid nitrogen. At the same time, the liquid nitrogen and the vaporized solvent have a large contact surface, resulting in good cooling effect. Compared with conventional multiple cooling pipes, this structure is simpler and easier to manufacture in the integrated molding process of the entire solvent dehydration and deoxygenation device.

[0043] All high-vacuum valves are high-vacuum Schlenk-type glass valves with plug threads fully covered by PTFE, which can be partially or fully opened when inert gas is introduced.

[0044] With this design, before the reaction, the sodium-potassium alloy, stir bar 5, and solvent can be added to reaction flask 1 under inert gas protection by fully opening the first high-vacuum valve 1-1. After the reaction, the first high-vacuum valve 1-1 can be partially opened, and the glass system can be rinsed by heating and reflux with the solution. After reflux, the first high-vacuum valve 1-1 can be completely closed, allowing the purified solvent to be completely collected in collection flask 2. After collection, the second high-vacuum valve 2-1 can be fully opened, and the purified liquid can be extracted using a syringe under inert gas protection. After use, the first high-vacuum valve 1-1 can be partially opened, allowing the solvent to flow back into reaction flask 1. Because this solvent dehydration and deoxygenation device has excellent sealing performance, the solvent can be stored in the reaction flask and used as needed.

[0045] In some embodiments, reaction flask 1 is a round-bottom flask with a volume of 150 mL to 2000 mL; collection flask 2 is a round-bottom flask with a volume not exceeding half the volume of reaction flask 1; the shortest distance between distillation neck 3 and collection flask 2 is greater than 1 cm; the shortest distance between liquid nitrogen cold trap 4 and collection flask 2 is greater than 1 cm; and the glass thickness at liquid nitrogen cold trap 4 is not less than 1 mm. In some embodiments, both the second high-vacuum gate 2-1 and the first high-vacuum gate 1-1 are valves fitted with fully PTFE-coated sealed plugs. Stirrer 5 is a fully glass-coated magnetic stirrer.

[0046] In summary, this invention can meet the needs of extremely sensitive chemical reaction systems, does not require mastery of glass firing processes, lowers the experimental threshold of conventional potassium-sodium alloy drying solvent methods, and can be reused multiple times, avoiding the safety hazards caused by residual metals after each drying process in common potassium-sodium alloy drying solvent methods.

[0047] Example 1

[0048] Taking the organic solvent tetrahydrofuran as an example, the specific process of using the purification method of this application is as follows: First, the purification equipment is dried in an oven at above 110°C for more than 30 minutes; after drying, it is transferred to a glove box, and in the glove box, the glass stir bar 5 and the potassium-sodium alloy are introduced into the reaction flask 1 through the first high-vacuum valve 1-1; the double-row tube is repeatedly evacuated and filled with high-purity (99.999%) argon gas three times through the second high-vacuum valve 2-1, with the vacuum degree reaching 100 mba each time. Then, the second high-vacuum valve 2-1 is partially opened to allow argon gas to flow into the device at a rate of not less than 70 ml / min to ensure that the device is used under a slightly positive pressure; the first high-vacuum valve 1-1 is fully opened, and tetrahydrofuran (anhydrous grade) is introduced into the reaction flask 1 through the first high-vacuum valve 1-1; both high-vacuum valves are closed, and the solution is stirred with the potassium-sodium alloy for 3 hours. After stirring for 3 hours, the mixture was repeatedly evacuated and filled with high-purity (99.999%) argon gas three times through the second high-vacuum gate 2-1, each time reaching a vacuum level of 100 mba. The vacuum was then reduced more than twice, and liquid nitrogen was introduced into the liquid nitrogen cold trap. This process was repeated more than twice, ensuring a vacuum level of 600 mba each time. The reaction flask 1 was then heated with a hot air gun to distill the organic solvent, which was then stored in the collection flask 2 via the liquid nitrogen cold trap 4. Finally, the purified tetrahydrofuran was extracted using a syringe in an argon atmosphere through the first high-vacuum gate 2-1.

[0049] To better clarify the quality of the anhydrous and oxygen-free organic solvent obtained by the solvent purification device disclosed in this patent, the reaction rate of cyclohexene and lithium metal (Li) in tetrahydrofuran solvent is used as a benchmark to compare the quality of tetrahydrofuran obtained by different purification methods. (Cyclohexene undergoes a reduction reaction with lithium metal, gradually gaining electrons. This electron gain is accompanied by a change in the degree of molecular conjugation, resulting in a red shift in the absorption spectrum and a color change from pale yellow to dark green, dark purple, reddish brown, and dark brown. Since the cyclohexene anion is extremely sensitive to water and oxygen, the time it takes for its first reduced state to be generated in large quantities can be used as a criterion for judging the solvent quality.)

[0050] Table 1. Results of different purification methods for tetrahydrofuran

[0051]

[0052] Referring to Table 1, a comparison of the purification results of this example with existing techniques yields the following results: Molecular sieve-assisted double-row tube high-vacuum line operation is indeed unsuitable for particularly sensitive chemical reaction systems; the time required for purifying tetrahydrofuran with sodium plus benzophenone is 48 h, with a residual water content (ppm) of 43.4, a residual oxygen content (ppm) of 32.5, and a solvent color change time of 10 minutes during the reduction of cardiocyclohexene; the time required for purifying tetrahydrofuran with a commercial solvent purification system is 72 h, with a residual water content (ppm) of 0.8, a residual oxygen content (ppm) of 0.9, and a solvent color change time of 5 minutes during the reduction of cardiocyclohexene; while the time required for this example is 3 h, with a residual water content (ppm) of 0.05, a residual oxygen content (ppm) of 0.08, and a solvent color change time of 10 seconds during the reduction of cardiocyclohexene.

[0053] Example 2

[0054] Taking n-hexane as an example, the specific process of using the purification method of this application is as follows: First, the purification equipment is dried in an oven at above 110°C for more than 30 minutes; after drying, it is transferred to a glove box, and in the glove box, the glass stir bar 5 and the potassium-sodium alloy are introduced into the reaction flask 1 through the first high-vacuum valve 1-1; the double-row tube is repeatedly evacuated and filled with high-purity (99.999%) argon gas three times through the second high-vacuum valve 2-1, with the vacuum degree reaching 100 mba each time. Then, the second high-vacuum valve 2-1 is partially opened to allow argon gas to flow into the device at a rate of not less than 70 L / min to ensure that the device is used under a slightly positive pressure; the first high-vacuum valve 1-1 is fully opened, and n-hexane (anhydrous grade) is introduced into the reaction flask 1 through the first high-vacuum valve 1-1; both high-vacuum valves are closed, and the solution is stirred with the potassium-sodium alloy for 12 hours. After stirring for 12 hours, the mixture was repeatedly evacuated and filled with high-purity (99.999%) argon gas three times through the second high-vacuum gate 2-1, each time reaching a vacuum level of 100 mba. The vacuum was then reduced more than twice, and liquid nitrogen was introduced into the liquid nitrogen cold trap. This process was repeated more than twice, ensuring a vacuum level of 600 mba each time. The reaction flask 1 was then heated with a hot air gun to distill the organic solvent, which was then stored in the collection flask 2 via the liquid nitrogen cold trap 4. Finally, the purified n-hexane was extracted using a syringe in an argon atmosphere through the first high-vacuum gate 2-1.

[0055] Table 2 Results of different purification methods for n-hexane

[0056]

[0057] Referring to Table 2, a comparison of the purification results of this example with existing technologies yields the following results: the time required for molecular sieve-assisted double-row tube high-vacuum line operation is 100 h, with a residual water content (ppm) of 0.88 and a residual oxygen content (ppm) of 102; the time required for sodium plus benzophenone is 48 h, with a residual water content (ppm) of 27.8 and a residual oxygen content (ppm) of 33.4; the time required for commercial solvent purification system is 72 h, with a residual water content (ppm) of 0.7 and a residual oxygen content (ppm) of 0.8; while the time required for this example is 12 h, with a residual water content (ppm) of 0.05 and a residual oxygen content (ppm) of 0.1.

[0058] Example 3

[0059] Taking diethylene glycol dimethyl ether as an example, the specific process of using the purification method of this application is as follows: First, the purification equipment is dried in an oven at 110°C or above for more than 30 minutes; after drying, it is transferred to a glove box, and the glass stir bar 5 and potassium-sodium alloy are introduced into the reaction flask 1 through the first high-vacuum valve 1-1 in the glove box; the double-row tube is repeatedly evacuated and filled with high-purity (99.999%) argon gas three times through the second high-vacuum valve 2-1, with the vacuum degree reaching 100 mba each time. Then, the second high-vacuum valve 2-1 is partially opened to allow argon gas to flow into the device at a rate of not less than 70 ml / min to ensure that the device is used under a slightly positive pressure; the first high-vacuum valve 1-1 is fully opened, and diethylene glycol dimethyl ether (anhydrous grade) is introduced into the reaction flask 1 through the first high-vacuum valve 1-1. The two high-vacuum valves are then closed, and the solution is stirred with the potassium-sodium alloy for 12 hours. After stirring for 12 hours, the mixture was repeatedly evacuated and filled with high-purity (99.999%) argon gas three times through the second high-vacuum gate 2-1, with the vacuum level reaching 100 mba each time. The pressure was then reduced more than twice, and liquid nitrogen was introduced into the liquid nitrogen cold trap. This process was repeated more than twice, ensuring the vacuum level reached 600 mba each time. The reaction flask 1 was then heated with a hot air gun to distill the organic solvent, which was then stored in the collection flask 2 via the liquid nitrogen cold trap 4. Finally, the purified diethylene glycol dimethyl ether was extracted using a syringe in an argon atmosphere through the first high-vacuum gate 2-1.

[0060] Table 3. Results of different purification methods for diethylene glycol dimethyl ether

[0061]

[0062] Referring to Table 3, a comparison of the purification results of this example with those of existing technologies yields the following results: the commercial glass solvent purification system requires 72 h, with a residual water content (ppm) of 2 and a residual oxygen content (ppm) of 2; while this example requires 3 h, with a residual water content (ppm) of 0.1 and a residual oxygen content (ppm) of 0.09.

[0063] In summary, this application provides a recyclable solvent dehydration and deoxygenation device and method. Using this equipment results in higher rapid dehydration and deoxygenation efficiency, making it better suited for sensitive chemical reaction systems. It should be noted that while high purification efficiency is a characteristic of potassium-sodium alloys, this invention provides a recyclable drying device and method that solves the problems associated with drying solvents for potassium-sodium alloys, such as the treatment of residual potassium-sodium alloys and the need for integrated, highly airtight devices. This method offers advantages such as low cost, ease of operation, and high safety.

[0064] Those skilled in the art should understand that variations can be implemented by combining existing technology with the above embodiments, which will not be elaborated here. Such variations do not affect the essence of the present invention, and will not be elaborated here either.

[0065] The preferred embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and the devices and structures not described in detail should be understood as being implemented in a conventional manner in the art. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the present invention. This does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention's technical solutions still fall within the protection scope of the present invention.

Claims

1. A solvent drying apparatus for drying organic solvents with potassium-sodium alloy and for recycling multiple times, characterized by: The application relates to a glass purification device and a high-vacuum valve, wherein the glass purification device comprises a reaction bottle (1) for distillation and a collecting bottle (2) arranged above the reaction bottle (1); the upper end of the collecting bottle (2) is communicated with the upper end of the reaction bottle (1) through a distillation neck (3); a liquid nitrogen cold trap (4) for condensation is arranged between the distillation neck (3) and the collecting bottle (2); a communication pipe (6) is arranged between the collecting bottle (2) and the reaction bottle (1); the communication pipe (6) communicates the collecting bottle (2) with the reaction bottle (1); the high-vacuum valve comprises a second high-vacuum valve (2-1) arranged on the collecting bottle (2) and a first high-vacuum valve (1-1) arranged on the communication pipe (6) and the collecting bottle (2); the first high-vacuum valve (1-1) is closed or partially opened through a valve core to control the communication pipe (6) and then selectively control the communication between the collecting bottle (2) and the reaction bottle (1); the second high-vacuum valve (2-1) is provided with an air outlet (7); the reaction bottle (1) is provided with sodium-potassium alloy and a stirring rod (5); the first high-vacuum valve (1-1) is fully opened to feed and add the stirring rod (5) under inert gas; the second high-vacuum valve (2-1) is fully opened to collect the purified liquid under inert gas; the liquid nitrogen cold trap (4) comprises a hollow condensation cup (4-1) and a liquid nitrogen pool (4-2) formed by the condensation cup (4-1); the condensation cup (4-1) is respectively communicated with the distillation neck (3) and the collecting bottle (2); the liquid nitrogen pool (4-2) can store liquid nitrogen; the reaction bottle (1) is a round-bottom flask with a volume of 150 mL to 2000 mL; the collecting bottle (2) is a round-bottom flask with a volume not greater than half of the volume of the reaction bottle (1); the shortest distance between the distillation neck (3) and the collecting bottle (2) is greater than 1 cm; the shortest distance between the liquid nitrogen cold trap (4) and the collecting bottle (2) is greater than 1 cm; the glass thickness of the liquid nitrogen cold trap (4) is not less than 1 mm; the first high-vacuum valve (1-1) and the second high-vacuum valve (2-1) are high-vacuum Schlenk type glass valves which are fully covered by tetrafluoroethylene and are sealed by plug threads; the air outlet (7) is connected with a double-pipe; under the cooperation of the double-pipe, the air pressure in the device is adjusted under inert gas; the stirring rod (5) is a glass fully-covered magnetic stirring rod; the solvent drying device is used to perform the following steps: S1, after the whole solvent water and oxygen removing device is baked through an oven, the double-pipe is used to repeatedly vacuumize and fill inert gas through the air outlet (7) three times to build a water-free and oxygen-free internal environment of the device; the stirring rod (5), the sodium-potassium alloy and the organic solvent are put into the reaction bottle (1) through the first high-vacuum valve (1-1); during the period, the device is always required to be kept in a micro-positive pressure; ​ ​ ​ 2. The solvent drying device for drying organic solvent with potassium-sodium alloy and for multiple use according to claim 1, characterized in that, ​ 3. The solvent drying device for drying organic solvent with potassium-sodium alloy and for multiple use according to claim 1, characterized in that, ​ 4. The solvent drying device for drying organic solvent with potassium-sodium alloy and for multiple use according to claim 1, characterized in that, ​ ​ 5. A solvent drying method for drying an organic solvent with a potassium-sodium alloy and recycling the solvent for multiple uses, characterized by, ​ ​ ​ ​ S2, stirring the organic solvent in the reaction bottle (1) by the stirrer (5); S3, using double-pipe to repeatedly reduce the pressure in the device through the second high vacuum gate (2-1) not less than 2 times, then pour liquid nitrogen into the liquid nitrogen cold trap (4), and then repeat the reduction of pressure not less than 2 times; S4, baking the reaction bottle (1) to make the organic solvent distill and condense in the liquid nitrogen cold trap (4) and store in the collection bottle (2); S5, extracting the treated organic solvent through the second high vacuum gate (2-1) under the protection of inert gas, and in this process, keeping the device in a slightly positive pressure; S6, after use, open the first high vacuum gate (1-1) to make the unused residual organic solvent in the collection bottle (2) be recycled to the reaction bottle (1).

6. The solvent drying method according to claim 5, wherein, in step S1, the stirrer (5) and the potassium-sodium alloy are first put into the reaction bottle (1) through the first high vacuum gate (1-1) in a glove box, and then the required organic solvent is put into the reaction bottle (1) through the first high vacuum gate (1-1) after repeatedly vacuumizing and filling inert gas three times on the double-pipe. In step S1, the solvent water and oxygen removal device is baked at a temperature not less than 80° for not less than 30 minutes to remove the residual water on the surface of the glass.

7. The method of claim 5, wherein the method is characterized by, The inert gas refers to a gas that is chemically inert and relatively stable, including but not limited to helium, nitrogen, and argon with a purity not less than 99.999%.

8. The method of claim 5, wherein the method is characterized by, The vacuum degree of repeated vacuumization and pressure reduction is not more than 100 mbar each time.

9. The method of claim 6, wherein the method is characterized by, In steps S1 and S5, the speed of inert gas flowing into the device is not less than 70 ml / min to ensure that the pressure of the glass device is always slightly positive.

10. The solvent drying apparatus and method of claim 6, wherein, ​

Images