Butyl lithium solid-liquid separation continuous reaction device and butyl lithium preparation method

Abstract

The invention discloses a butyl lithium solid-liquid separation continuous reaction device and a butyl lithium preparation method. According to the reaction device, through double-layer convection stirring and a baffle plate with a pyramid tip, full contact of metal lithium and halogenated alkane is realized on the premise of not dispersing lithium, the problem of excessive consumption of the metal lithium and the halogenated alkane is solved, and the problem of blockage of a filtering device in a traditional process is solved through a top discharging and bottom filtering mode; according to the method, excessive lithium metal and halogenated alkane react in the liquid-phase solvent, so that the yield of halogenated alkane is increased, excessive lithium can continue to participate in the synthesis reaction of the next kettle of butyl lithium, the content of lithium metal in the product discharged from the reactor is greatly reduced in the process on the premise of ensuring the yield of the butyl lithium product, the utilization rate of lithium is increased, and the production cost is reduced. And industrial production is facilitated.

Description

Technical Field

[0001] The invention relates to a method for producing butyl lithium, in particular to a butyl lithium solid-liquid separation continuous reaction device and a method for preparing butyl lithium, and belongs to the technical field of anion initiator preparation. Background Art

[0002] As is known to all, butyllithium, including n-butyllithium, sec-butyllithium and tert-butyllithium, is mainly used as the initiator of anionic polymers. Its traditional method is to disperse lithium into micron-sized lithium sand under high-speed stirring at high temperature in white oil, then adopt micron-sized metallic lithium sand and corresponding chlorobutane to react in liquid hydrocarbon solution, separate butyllithium solution and lithium slag after the reaction, the main component of the gained lithium slag is lithium chloride, lithium oxide, lithium hydroxide and residual metallic lithium, and the lithium slag is hydrolyzed. The representative of this type of method is disclosed as Chinese patent (CN1443767A) to adopt the traditional method to synthesize n-butyllithium, and Chinese patent (CN103044461B) to disclose the method for synthesizing tert-butyllithium by the above method. Micron-sized lithium sand has a large specific surface area. When reacting with the corresponding chlorobutane, the contact area that can participate in the reaction is extremely large, and the reaction rate is also extremely fast. It is necessary to quickly remove the heat and control the reaction rate by controlling the dripping rate of chlorobutane. The reaction temperature is not easy to control, and in order to ensure that the chlorobutane reacts as completely as possible, the amount of lithium added must be higher than the theoretical ratio. The hydrolysis of lithium slag formed by unreacted metallic lithium and reaction by-products is not only dangerous but also wastes metallic lithium.

[0003] If a larger lithium ribbon, lithium sheet, lithium block or lithium particle is used to react with chlorobutane, the conversion rate of chlorobutane and the yield of the target product are still low even if a high excess of lithium is used or the reaction time is greatly extended. The reason is that no matter what shape, the lithium chloride generated by the reaction of larger lithium with chlorobutane will cover the surface of the metallic lithium, forming a protective layer, blocking the contact between chlorobutane and the lithium surface, greatly reducing the lithium surface area that can participate in the reaction, and passivating the activity of the residual lithium.

[0004] The experiment found that no matter what shape of lithium is used to react with chlorobutane, the density of the solvent used is higher than the density of lithium (0.534g / cm 3 ) is large, during the reaction, lithium first floats on the surface of the solvent. As the reaction proceeds, the generated lithium chloride covers the lithium surface. As the thickness of the covered lithium chloride increases, the density of the solid composed of the unreacted lithium and the lithium chloride on its surface also increases and sinks to the bottom of the solution. Under this condition, it is a long and difficult process to make the subsequently added chlorobutane completely react and convert it into butyl lithium.

[0005] The Chinese patent (CN215963491U) mentions the use of lithium particles for alkyl lithium synthesis. After the reaction is completed, the residual lithium particles are separated from the alkyl lithium and lithium halide by the screen in the reactor, solving the problem of lithium metal reuse. However, the screen in the reactor will hinder the contact between the lithium particles in the reactor and the halogenated hydrocarbons, affecting the reaction, and cannot solve the problem of the surface covering of the lithium particles.

[0006] The Chinese patent (CN113735670A) mentions the use of lithium particles and 2-chlorobutane to react to prepare sec-butyl lithium. After the reaction is completed, the reaction liquid is pumped into another tank to filter and separate the solid and sec-butyl lithium solution. The excess metal lithium is left in the reactor by installing a lithium particle separation device in the reactor. This method does not take into account that the surface of the excess metal lithium left behind is covered, which seriously reduces its reactivity with chlorobutane, and the subsequent reaction rate and the yield of the target product will be significantly affected.

[0007] The US patent (US5523447) describes the use of 0.635cm×1.905cm or 0.5cm×5.08cm or 0.635cm×1.905cm or 0.25cm×3.81cm lithium rods (surface area of ​​975.4cm 2 ) and anhydrous hexane react with n-butyl chloride, wherein the molar ratio of lithium to chlorobutane is 5 to 20, and n-butyl chloride is added dropwise to the reactor within 125 minutes and the reaction mass is stirred at 70° C. The liquid of the reaction mass containing the byproduct lithium chloride is filtered, the metallic lithium remaining in the reactor is washed with n-hexane, and the excess lithium not used in the reactor is retained for further reaction and cyclically prepared butyl lithium. In this invention, the amount of bulk lithium metal is as high as 10 times that of chlorobutane. The basis of this technology is to prepare butyl lithium by increasing its surface area with chlorobutane by using a large excess of lithium rods. When the lithium rods react with chlorobutane, trace oxygen in the system, trace water in the solvent and halogenated alkyl, and side reactions with the solvent itself, such as salts such as lithium oxide, lithium hydroxide and lithium chloride, will adhere to the surface of the lithium rods, reducing the effective reaction area of ​​lithium. The adhesion layer will inevitably hinder the contact between lithium and chlorobutane, reducing the collision probability between chlorobutane and lithium, resulting in a reduction in conversion efficiency. At the same time, it is not difficult to see from the examples that this technology can only achieve its effect when the amount of lithium used is less than 100g, and a large amount of lithium is used, which makes it difficult for this technology to meet the requirements of industrial production.

[0008] The prior art urgently needs a production method that overcomes the defects of heterogeneous reactions and improves the reaction efficiency and yield of butyl lithium. Summary of the invention

[0009] In view of the problems existing in the prior art, the first object of the present invention is to provide a butyl lithium solid-liquid separation continuous reaction device, which can effectively remove by-products and impurities in the process of synthesizing butyl lithium, such as lithium chloride, lithium oxide, lithium nitride and lithium hydroxide, which are covered on the lithium surface, from the surface of metallic lithium, thereby increasing the probability of contact and collision between the excess lithium surface and chlorobutane when circulating and participating in subsequent reactions, thereby improving the reaction rate and yield.

[0010] The second object of the present invention is to provide a method for preparing butyl lithium. The method uses millimeter-sized metallic lithium and halogenated alkane in a suitable ratio without dispersing lithium, and directly prepares butyl lithium including n-butyl lithium, sec-butyl lithium and tert-butyl lithium with high efficiency and high yield through a reaction device with a special structure. The butyl lithium prepared by the method can meet the requirements of being an anionic polymerization initiator.

[0011] In order to achieve the above technical purpose, the present invention provides a butyl lithium solid-liquid separation continuous reaction device, comprising a kettle (2), a stirring device (1) with stirring blades (4), a discharge pipe (5) with a filter screen (6) and a baffle (3) with a pyramid tip; the stirring device (1) is fixed on the central axis of the kettle (2) and extends into a critical depth where the horizontal cross-sectional area of ​​the kettle decreases; the baffles are evenly distributed on the inner wall of the kettle, and the angle between the side surface and the inner wall of the kettle is 45 to 60 degrees; the discharge pipe (5) is inserted from the top of the kettle (2) to a depth between the inner wall of the bottom of the kettle and the bottom of the stirring device, and the filter screen (6) is fixed to the bottom of the discharge pipe.

[0012] The flow formed by the reaction device provided by the present invention during stirring can knock large-sized particles onto the baffle plate for crushing and dispersion. The angle formed by the two side surfaces of the baffle plate and the wall of the reactor can withstand repeated collisions between lithium and the reaction liquid for a long time, which is convenient for the smooth rotation of the metallic lithium in the reactor and avoids the lithium centrifugally rotating with the liquid from accumulating between the baffle plate and the wall of the vessel. The outlet of the reaction device is located at the top of the reactor body, and the filter screen is arranged in the reactor body. By pressurizing the reactor, the liquid phase is forced to flow out from the top, and the filter residue containing unreacted metallic lithium obtained when filtering the liquid phase remains in the reactor. With the subsequent stirring reaction, it falls off, effectively solving the problem of the filter residue clogging the filter screen.

[0013] The present invention strictly limits the extension amount of the stirring device in the kettle body. The critical depth at which the horizontal cross-sectional area of ​​the kettle body becomes smaller is the depth of the connection between the reactor column and the bottom sphere. This can not only ensure the effectiveness of the flow in the kettle body during stirring, but also avoid excessive stirring resistance caused by excessive extension.

[0014] As a preferred solution, the stirring blades on the stirring device (1) are divided into two layers, the lower stirring blades are axial flow slurry stirring blades, and the upper stirring blades are radial flow slurry stirring blades.

[0015] As a preferred solution, the lower stirring blade is located at the bottom of the stirring device (1); the upper stirring blade is located at 1 / 3 to 1 / 2 of the depth of the kettle body. The stirring blades should be arranged strictly in accordance with the above requirements. The lower axial slurry flow can make the reaction materials convect up and down, effectively stirring the lithium particles settled at the bottom and the halogenated hydrocarbons, so that the two are fully in contact. The upper radial slurry flow can make the materials radially thrown to the baffle, effectively removing the covering on the lithium surface.

[0016] As a preferred solution, the number of baffles is 2 to 8, the depth of the pyramid tip on the baffle is 1 to 2 mm, and the distance between two adjacent pyramid tips is 3 to 10 mm. The setting of the pyramid tip is directly related to the movement trajectory of the metal lithium in the kettle body, and must be strictly implemented in accordance with the above requirements; if the depth of the pyramid tip is too shallow, it cannot effectively cut the covering on the surface of the lithium, and if it is too deep, it will seriously affect the movement of the metal lithium in the kettle body and easily produce dead zones; if the distance between two adjacent pyramid tips is too small, the metal lithium is easily stuck in the gap, and if it is too large, the probability of collision with the metal lithium is too low, resulting in too low efficiency in removing the adhesion on the lithium surface.

[0017] As a preferred solution, the length of the baffle is 2 / 3 to 3 / 4 of the height of the vertical reactor.

[0018] As a preferred solution, the number of meshes of the filter at the bottom of the discharge pipe is 10 to 30.

[0019] The present invention also provides a continuous preparation method of butyl lithium, which adopts any of the above-mentioned reaction devices to continuously prepare butyl lithium, firstly fills the kettle of the device with a protective atmosphere, adds a solvent and metallic lithium, starts stirring, and then adds a halogenated alkane to react, after the reaction is completed, the obtained reaction liquid is filtered through a filter screen and then discharged from a discharge pipe to obtain a butyl lithium crude solution; the butyl lithium crude solution is filtered through a sand core to obtain a butyl lithium solution.

[0020] As a preferred solution, the water content of the metal lithium is ≤20 mg / kg, and the particle size is 1.5 to 20 mm. The size of the metal lithium in any direction meets the above particle size requirements, regardless of the shape of the metal lithium, which can be in any shape such as rod, sheet, or special shape.

[0021] As a preferred solution, the water content of the halogenated alkane is ≤50 mg / kg.

[0022] As a preferred solution, during the reaction, the stirring rate is 150 to 300 r / min, and after the reaction is completed, the stirring rate is reduced to 40 to 60 r / min.

[0023] As a preferred embodiment, the halogenated alkane is 1-chlorobutane, 1-chloropentane, 1-chlorohexane, 1-chlorooctane, 1-chlorodecane, 1-chlorododecane, 2-chlorobutane, 2-chloropentane, 1-chloro-2-methylbutane, 1-chloro-2-ethylhexane and 1-chloroisooctane. More preferably, the halogenated alkane is 1-chlorobutane.

[0024] As a preferred solution, the molar ratio of the metal lithium to the halogenated alkane is 2.1 to 10:1; the solvent is cyclohexane and / or n-hexane. The ratio of the metal lithium to the halogenated alkane must be strictly implemented in accordance with the above requirements. When the ratio is too low, the conversion of chlorobutane is incomplete, and the product contains more by-products and impurities, which makes it difficult to meet the performance requirements of the anion initiator; when the ratio is too high, the stirring resistance during the reaction process will be too large, and too much space in the reactor will be occupied, resulting in a decrease in yield.

[0025] As a preferred solution, the reaction temperature is higher than the solidification point of the solvent and lower than the boiling point of the solvent, and is 10 to 85° C. More preferably, the reaction temperature is 40 to 75° C.

[0026] As a preferred solution, the halogenated alkane is added dropwise for 1 to 2 hours. After the addition is completed, the reaction is continued by stirring for 1 to 4 hours.

[0027] The present invention provides a device and method for directly separating unreacted lithium from a butyl lithium reaction mixture system and continuing to participate in subsequent reactions. Since the density of metallic lithium is relatively small, when cyclohexane or normal hexane is used, the metallic lithium participating in the reaction at the beginning floats on the liquid surface. When stirring is turned on, the lithium is concentrated around the stirring blade and the stirring shaft. As the reaction product covering the surface of lithium increases, its density increases, and the centrifugal force generated under rapid stirring increases. The lithium is further away from the stirring blade and the stirring shaft and closer to the reactor wall. Therefore, a baffle with a pyramid tip is installed on the reactor wall. In the process of lithium splashing and colliding with the rotating flow of liquid, lithium with more surface coverings is closer to the baffle. Through shearing and friction between the pyramid tip on the baffle and lithium, and between lithium and lithium, the coverings on the surface of lithium can be more effectively removed and enter the solution system. At the same time, the active surface of the single lithium is increased, the contact area between lithium and chlorobutane is increased, and the reaction efficiency of lithium and chlorobutane and the yield of butyl lithium are improved.

[0028] The present invention also provides a detailed preparation method of butyl lithium, the specific process is:

[0029] 1) Under argon protection, in a reaction kettle equipped with a double-layer stirring and a baffle with a pyramid tip, a certain amount of solvent with a water content of less than 20 mg / kg and commercially available millimeter-sized lithium are added, stirring is started, the stirring rate is controlled at 150-300 r / min, and chlorobutane with a water content of less than 50 mg / kg is added dropwise, the reaction temperature is maintained at 50-75° C., the chlorobutane addition time is maintained at 60-120 min, and after the chlorobutane is added dropwise, stirring is continued for 1-4 hours to react;

[0030] 2) After the reaction is completed, the stirring is slowed down to 50r / min, and the material is discharged under pressure while stirring without standing and settling. The filter screen at the discharge port intercepts the unreacted lithium for preliminary filtration and discharge. The reaction product butyl lithium and the by-product lithium chloride in the reaction liquid are pressed out of the reactor together, while the excess unreacted lithium is retained in the reactor to participate in the next synthesis reaction;

[0031] 3) The liquid squeezed out from the reactor is further filtered through a sand core filter, and the resulting filter residue is lithium chloride and a very small amount of lithium residue. The filtrate is a colorless to light yellow transparent solution, which is the product butyl lithium solution of the present invention.

[0032] In the prior art, butyl lithium is prepared directly with millimeter-level lithium without a lithium dispersion step and without a method for removing lithium surface adhesion. The process causes byproducts such as lithium chloride to adhere to the lithium surface during the reaction, blocking chlorobutane from attacking lithium, reducing the reactivity of lithium and chlorobutane, reducing the specific surface area of ​​lithium during the reaction, and increasing the reaction time. Not only does the production efficiency decrease, but the probability of octane as a byproduct of the reaction of chlorobutane and butyl lithium is also increased. The above defects restrict the improvement of the yield of butyl lithium in the preparation of butyl lithium and the utilization rate of expensive lithium. The present invention effectively overcomes the above defects. During the reaction process, the reactor with a special structure is used to continuously remove the byproducts adhering to the lithium surface, generating a new lithium active surface, which can effectively shorten the reaction time, while reducing the probability of octane as a byproduct, improving the reaction efficiency of chlorobutane and the yield of the target product butyl lithium and the utilization rate of lithium.

[0033] Compared with the prior art, the beneficial technical effects of the present invention are:

[0034] 1) Compared with the prior art, the preparation method provided by the present invention omits the lithium dispersion step, shortens the process, simplifies the operation, reduces energy consumption, and after the synthesis reaction of the present invention is completed, part of the lithium that does not participate in the reaction will not be hydrolyzed together with the filtered lithium slag, but will continue to remain in the reactor to participate in the next reactor reaction, which can significantly reduce the consumption of lithium.

[0035] 2) The reaction device provided by the present invention realizes high surface activity of metallic lithium and sufficient contact with halogenated alkanes without dispersing lithium through double-layer convection stirring and baffles with pyramidal tips, thereby overcoming the problem of insufficient activity of metallic lithium due to surface covering and insufficient reaction with halogenated alkanes in a short period of time. In addition, the problem of clogging of the filtration device in the traditional process is solved by the top discharge and bottom filtration.

[0036] 3) The design of the reactor and the method for preparing butyl lithium provided by the present invention are simple. Under the premise of ensuring the yield of the butyl lithium product, the content of metallic lithium in the product is greatly reduced, and the utilization rate of lithium is improved. The reaction has few side reactions, the process is easy to control, and it is easy to industrialize production. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the reaction device in Examples 1 to 7 of the present invention;

[0038] 1 is a stirring device, 2 is a reactor body, 3 is a baffle, 4 is a stirring blade, 5 is a discharge pipe, and 6 is a filter screen fixed at the discharge pipe port;

[0039] Figure 2 Schematic diagram of a baffle with a pyramid tip in a reaction device in Examples 1 to 7 of the present invention;

[0040] Where D represents the tooth depth on the baffle;

[0041] Figure 3 It is a top view of the baffle with pyramidal tip in the reaction device in Examples 1 to 7 of the present invention. DETAILED DESCRIPTION

[0042] To facilitate understanding of the content of the present invention, the present invention will be described in more detail and comprehensively with reference to the relevant drawings. The drawings show preferred embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the content described herein.

[0043] In the following examples, the GB / T4369-2015 method was used to determine the lithium content; the double titration-benzyl chloride method was used to determine the concentration and impurity content of butyl lithium; and the gas chromatography method was used to determine the content of butyl chloride and octane.

[0044] Result calculation method:

[0045] The yield of butyl lithium based on chlorobutane = the actual number of moles of butyl lithium / the total number of moles of chlorobutane added × 100%.

[0046] Example 1

[0047] Synthesis of n-butyllithium from millimeter-sized lithium particles using a reactor with pyramid-shaped baffles

[0048] Structure and setting of the reactor: A steel reactor with a diameter of 1000mm and a height of 2000mm (height / diameter = 2.0) is equipped with a stirring shaft with double-layer stirring blades. The lower stirring blades are axial flow slurry stirring blades, and the upper stirring blades are radial flow slurry stirring blades. The reactor is equipped with four baffles. The pyramid tip of the baffle is 1mm deep, the distance between two adjacent pyramid tips is 8mm, and the length of the baffle is 1334mm, which is about 2 / 3 of the reactor height. Argon and 500 liters of n-hexane were filled into the above-designed dry reactor equipped with a reflux condenser, a temperature indicating device and a jacketed heat transfer, and then 29.18 kg (4.2 kmol) of lithium metal particles with a diameter of 3 mm to 6 mm and a length of 6 mm to 10 mm, which were approximately cylindrical, were added. Stirring was started, and then 186.0 kg (2.0 kmol) of n-butyl chloride was continuously and evenly added dropwise within 65 minutes. The stirring speed was adjusted to 200 rpm, and cooling water was introduced through the jacket to remove the reaction heat, and the reaction temperature was controlled at 50 to 65° C. After stirring for another hour, sampling was performed. The reaction solution was observed to be white and turbid, the appearance and size of the cylindrical lithium did not change significantly, and the surface of the lithium particles still showed a metallic luster; after stirring for another hour, the mass fraction of n-butyl chloride in the reaction solution was measured to be 0.48%, and the appearance of the solution was off-white; after continuing the reaction for another hour, the size of the lithium particles became smaller but still remained cylindrical, a small part of the surface of the lithium particles was adhered by lithium chloride, and was light off-white without metallic luster, and most of the surface still showed metallic luster, and the sampled solution changed from the previous gray-brown to light white, in which the mass fraction of n-octane was analyzed to be 1.64%, and no n-butyl chloride was contained. Stop stirring and cool to room temperature, filter the reaction solution through a filter press, and obtain a colorless and transparent butyl lithium solution, the technical indicators of which are shown in Table 1.

[0049] Example 2

[0050] The relevant settings and synthesis process conditions of this embodiment are the same as those in Example 1, except that the amount of metallic lithium is increased to lithium: chlorobutane ≌ 5: 1 (molar ratio), and 69.43 kg is added on the basis of the residual lithium in Example 1 to continue the reaction.

[0051] Example 3

[0052] The relevant settings and synthesis process conditions in this embodiment are the same as those in Example 1, except that the amount of metallic lithium is increased to lithium: chlorobutane ≌ 10: 1 (molar ratio), and 27.78 kg of lithium is added on the basis of the residual lithium in Example 2 to continue the reaction.

[0053] Example 4

[0054] The relevant settings and synthesis process conditions of this embodiment are the same as those of embodiment 1, except that the baffles with pyramid tips are changed to two. The results are shown in Table 1

[0055] Example 5

[0056] The relevant settings and synthesis process conditions of this embodiment are the same as those of embodiment 1, except that the number of baffles with pyramid tips is changed to 8. The results are shown in Table 1

[0057] Example 6

[0058] The relevant settings and synthesis process conditions in this example are the same as those in Example 1, except that the reaction time is extended to 9 hours. The results are shown in Table 1

[0059] Example 7

[0060] The relevant settings and synthesis process conditions of this embodiment are the same as those of Example 1. Millimeter-sized lithium particles are used to synthesize sec-butyl lithium. Only n-butyl chloride is replaced by sec-butyl chloride. Before adding sec-butyl chloride, the temperature of the material in the reactor is raised to 40°C under stirring, and then sec-butyl chloride is added. The results are shown in Table 1

[0061] Comparative Example 1

[0062] Synthesis of n-butyl lithium by micron-scale lithium sand method using common reactor

[0063] In an argon atmosphere, a steel reactor with a diameter of 1000 mm and a height of 2000 mm (height / diameter = 2.0) was provided with a stirring shaft with double-layer stirring blades, the stirring blades had the same stirring flow direction, and four ordinary baffles without pyramid tips were installed in the reactor. 29.18 kg (4.2 kmol) of lithium sand (produced by Shanghai Oujin Industrial Co., Ltd., with a particle size of 48 um) and 500 liters of n-hexane were added to the reactor at the outlet without a filter screen. The mixture was stirred and 186.0 kg (2.0 kmol) of n-butyl chloride (NBC) was added dropwise within 65 minutes, and the reaction temperature was controlled at 50-65° C. by cooling. Samples of the reaction materials were collected regularly during the addition, and the presence of butyl chloride was monitored by gas chromatography through the hydrolysis sample. After the addition of n-butyl chloride was completed, the mixture was stirred for about 3.0 hours. The content of n-butyl chloride was monitored to be as low as the lower limit of chromatographic detection and could not be detected. All the materials were pressed out of the reactor and filtered again. The filter residue was washed with anhydrous hexane to obtain the final filter residue, and a clear colorless product butyl lithium solution and an off-white filter residue were obtained. The technical indicators are shown in Table 1.

[0064] Comparative Example 2

[0065] Synthesis of n-butyl lithium from millimeter-sized lithium particles using a common reactor

[0066] The synthesis process is unchanged from that in Example 1, except that the reactor is replaced with an ordinary reactor equipped with a baffle plate without a pyramid tip and two layers of co-directional paddle stirring.

[0067] After the reaction is completed, all materials are pressed out of the reactor, the reaction material is filtered and the solid residue is washed with anhydrous hexane to obtain a clear light yellow product butyl lithium solution and an off-white powder with unreacted lithium particles and an off-white surface. Its technical indicators are shown in Table 1.

[0068] Comparative Example 3

[0069] Synthesis of n-butyl lithium from millimeter-sized lithium particles using a common reactor

[0070] The facilities and synthesis process in Comparative Example 2 remain unchanged, except that the ratio of lithium to n-butyl chloride is increased to 5:1 (molar ratio). The results are shown in Table 1

[0071] Comparative Example 4

[0072] Synthesis of sec-butyl lithium by micron-scale lithium sand method using common reactor

[0073] The relevant settings and synthesis process in Comparative Example 1 remain unchanged, except that n-butyl chloride is replaced with sec-butyl chloride to synthesize sec-butyl lithium. The results are shown in Table 1

[0074] Comparative Example 5

[0075] Synthesis of sec-butyl lithium from millimeter-sized lithium particles using a common reactor

[0076] The synthesis process is unchanged from that in Comparative Example 3, except that n-butyl chloride is replaced by sec-butyl chloride. Its technical indicators are shown in Table 1.

[0077] Table 1 Technical indicators of the products obtained in Examples 1 to 7 and Comparative Examples 1 to 5

[0078]

[0079]

[0080] It can be seen from the data in Table 1 that the reaction time is too long and the probability of side reactions increases; when the reactor of the present invention is used to synthesize butyl lithium with millimeter-sized lithium particles, the final result is close to the yield and side reaction effect of synthesizing butyl lithium with micron-sized lithium sand using an ordinary reactor, but the unreacted lithium remaining in the filter residue is obviously lower in the former than in the latter; and when an ordinary reactor is used to synthesize butyl lithium with millimeter-sized lithium particles, the reaction rate decreases, and when the reaction time is about 4 hours, the reaction is not complete and the yield decreases significantly.

Claims

1. A butyllithium solid-liquid separation continuous reaction device, characterized in that: The invention comprises a kettle body (2), a stirring device (1) with stirring blades (4), a discharge pipe (5) with a filter screen (6), and a baffle (3) with a pyramidal tip; the stirring device (1) is fixed on the central axis of the kettle body (2) and extends into a critical depth at which the horizontal cross-sectional area of ​​the kettle body decreases; the baffles are evenly distributed on the inner wall of the kettle body, and the angle between the side surface and the inner wall of the kettle body is 45 to 60 degrees; the discharge pipe (5) is inserted from the top of the kettle body (2) to a depth between the inner wall of the bottom of the kettle body and the bottom of the stirring device, and the filter screen (6) is fixed to the bottom of the discharge pipe.

2. A butyllithium solid-liquid separation continuous reaction device according to claim 1, characterized in that: The stirring blades on the stirring device (1) are divided into two layers, the stirring blades on the lower layer are axial flow slurry stirring blades, and the stirring blades on the upper layer are radial flow slurry stirring blades.

3. A butyllithium solid-liquid separation continuous reaction device according to claim 2, characterized in that: The lower stirring blades are located at the bottom of the stirring device (1); and the upper stirring blades are located at 1 / 3 to 1 / 2 of the depth of the kettle body.

4. A butyllithium solid-liquid separation continuous reaction device according to claim 1, characterized in that: The number of the baffles is 2 to 8, the depth of the pyramid tips on the baffles is 1 to 2 mm, and the distance between two adjacent pyramid tips is 3 to 10 mm.

5. The butyl lithium solid-liquid separation continuous reaction device according to claim 1, characterized in that: The length of the baffle is 2 / 3 to 3 / 4 of the height of the vertical reactor; the number of meshes of the filter at the bottom of the discharge pipe is 10 to 30.

6. A continuous preparation method of butyl lithium, characterized in that: The device according to any one of claims 1 to 5 is used to continuously prepare butyl lithium. A protective atmosphere is first filled into the reactor of the device, and a solvent and metallic lithium are added, stirring is started, and then a halogenated alkane is added for reaction. After the reaction is completed, the obtained reaction liquid is filtered through a filter and discharged from a discharge pipe to obtain a crude butyl lithium solution; the crude butyl lithium solution is filtered through a sand core to obtain a butyl lithium solution.

7. The method for continuously preparing butyl lithium according to claim 6, characterized in that: The water content of the metallic lithium is ≤20 mg / kg, and the particle size is 1.5-20 mm; the water content of the halogenated alkane is ≤50 mg / kg.

8. The method for continuously preparing butyl lithium according to claim 6, characterized in that: During the reaction, the stirring rate is 150-300 r / min, and after the reaction is completed, the stirring rate is reduced to 40-60 r / min.

9. The method for continuously preparing butyl lithium according to claim 6, characterized in that: The halogenated alkanes are 1-chlorobutane, 1-chloropentane, 1-chlorohexane, 1-chlorooctane, 1-chlorodecane, 1-chlorododecane, 2-chlorobutane, 2-chloropentane, 1-chloro-2-methylbutane, 1-chloro-2-ethylhexane and 1-chloroisooctane.

10. The method for continuously preparing butyl lithium according to claim 6, characterized in that: The molar ratio of the metallic lithium to the halogenated alkane is 2.1-10:1; and the solvent is cyclohexane and / or n-hexane.

11. The method for continuously preparing butyl lithium according to claim 6, characterized in that: The reaction temperature is higher than the solidification point of the solvent and lower than the boiling point of the solvent, and is 10 to 85°C.

12. The method for continuously preparing butyl lithium according to claim 6, characterized in that: The halogenated alkane is added dropwise for 1 to 2 hours. After the addition is completed, the reaction is continued by stirring for 1 to 4 hours.

Images