A device and process for purifying trimethylaluminum

Abstract

The application is suitable for the technical field of metal source organic synthesis, and provides a trimethylaluminum purification device and process, which comprises a reaction device, a reflux device and a vacuum rectification device, the vacuum rectification device is connected with a shunt device through a pipeline connecting piece, the shunt device comprises a rotating cylinder, a rotating assembly is connected to the side wall of the rotating cylinder, a main flow pipe is installed in the rotating cylinder, one end of the main flow pipe is connected with the vacuum rectification device through a diversion pipe, and the other end of the main flow pipe is positioned and butt-jointed with a shunt assembly through a positioning assembly; by adding high-purity triethylaluminum into trimethylaluminum crude product containing dimethylaluminum chloride, pure trimethylaluminum can be obtained through rectification after reaction, and the purification of trimethylaluminum crude product is realized; in the process of rectifying the trimethylaluminum after reaction, the liquid obtained in the process of rising temperature and the liquid under the temperature stable state can be separated through the shunt device, and the purity of the trimethylaluminum can be further ensured.

Description

Technical Field

[0001] This invention belongs to the field of metal-source organic synthesis technology, and particularly relates to a trimethylaluminum purification device and process. Background Technology

[0002] MO sources, or high-purity organometallic compounds, are supporting materials for growing semiconductor microstructures using advanced techniques such as metal-organic chemical vapor deposition (MOCVD) and metal-organic molecular beam epitaxy (MOMBE). Because MO source products require extremely high purity, and most MO source compounds are extremely sensitive to oxygen and water—capable of spontaneous combustion in air and explosion in water—the development of MO sources is a high-tech process integrating synthesis and preparation under extreme conditions, ultrapure purification, ultrapure analysis, and ultrapure filling.

[0003] High-purity trimethylaluminum is one of the main MO sources, widely used in solar energy, organic Al sources for full-color LEDs, third-generation semiconductors, and high-K materials for radio frequency integrated circuits. The performance of the deposited layers in these semiconductor materials is highly dependent on the purity of trimethylaluminum; even trace amounts of impurities can affect its performance. Due to the preparation process, the main impurities in trimethylaluminum are organosilicon, organic oxygen, and organochlorine introduced during the synthesis stage, which seriously affect the performance of trimethylaluminum. Among these, the chlorine impurity, dimethylaluminum chloride (Me2AlCl), has the same boiling point as trimethylaluminum and cannot be removed by conventional distillation. Therefore, developing an efficient and simple process for preparing high-purity trimethylaluminum is particularly important.

[0004] Chinese invention patent CN114011353B discloses a high-purity trimethylaluminum preparation device and its usage method. The high-purity trimethylaluminum preparation device consists of four systems: a sodium reduction purification system, a physical chromatography filtration device, a distillation purification system, and a photocatalytic tail gas absorption tank. The sodium reduction purification system comprises a purification kettle and an oil bath. The distillation purification system comprises a final distillation kettle and a primary distillation kettle. The physical chromatography filtration device is a three-layer chromatography device consisting of activated carbon with a particle size of 1μm~2μm as the upper layer, austenitic stainless steel particles with a particle size of 0.5μm~0.8μm as the middle layer, and alumina powder with a particle size of 0.1μm~0.2μm as the bottom layer. The treatment liquid in the photocatalytic tail gas absorption tank is a turbid liquid formed by mixing hydrogen dioxide and titanium dioxide at a mass ratio of 200:1~2 and maintaining uniform stirring. The product prepared by this invention has high purity, good stability, easy and controllable process, and complete and clean tail gas treatment.

[0005] However, the aforementioned patents still have some shortcomings:

[0006] The aforementioned invention mainly employs physical chromatography and two-stage distillation to purify the initially prepared trimethylaluminum obtained in step S2③ to obtain the desired electronic-grade trimethylaluminum. However, this purification method cannot remove some impurities with boiling points close to that of trimethylaluminum. Furthermore, during the distillation purification process using the distillation purification system, the chromatographically purified trimethylaluminum obtained in step S3① needs to be sequentially added to the initial distillation vessel and the final distillation vessel under nitrogen protection. The distillation temperature of the initial distillation vessel is set to 132℃~137℃, and the distillation temperature of the final distillation vessel is set to 118℃~123℃. Since there is a gradual temperature increase during the distillation process, it is necessary to separate the distillation product obtained in the heating stage from the distillation product obtained in the constant temperature stage; otherwise, the purity of the final trimethylaluminum will be reduced. Summary of the Invention

[0007] This invention provides a trimethylaluminum purification apparatus and process, which aims to overcome the shortcomings and defects of the prior art mentioned in the background section. The trimethylaluminum purified by this apparatus and process has high purity, high yield, and is simple to operate.

[0008] This invention is implemented as follows: a trimethylaluminum purification apparatus includes a reaction device, a reflux device, and a vacuum distillation device. The reaction device is connected to the reflux device and the vacuum distillation device via pipe fittings. A flow divider is connected to the vacuum distillation device via pipe fittings. The flow divider includes a rotating cylinder with a rotating assembly connected to its side wall. A main flow pipe is installed inside the rotating cylinder. One end of the main flow pipe is connected to the vacuum distillation device via a deflector, and the other end of the main flow pipe is positioned and connected to the flow divider via a positioning assembly. In this scheme, the flow divider can divide the liquid obtained from the vacuum distillation device, thereby improving the purity of the trimethylaluminum product.

[0009] Preferably, the diversion assembly includes a diversion cylinder with a plurality of holes. The holes are evenly arranged around the axis of the diversion cylinder. Rotating the rotating cylinder causes the main flow pipe to connect with the pipes installed in different holes on the diversion cylinder through a positioning assembly to achieve diversion of the distilled liquid. In this scheme, the rotating assembly controls the rotating cylinder to drive the main flow pipe to rotate, so that the main flow pipe connects with the pipes in different holes to separate the distilled liquid obtained at different temperature stages.

[0010] Preferably, the rotating assembly includes a rotary motor, the output shaft of which is connected to a rotating rod. A drive wheel is fitted onto the side wall of the rotating rod, and the drive wheel is connected to the rotating cylinder via a driven wheel. In this configuration, the rotary motor controls the rotating rod to drive the drive wheel to rotate, thereby causing the driven wheel to drive the rotating cylinder to rotate.

[0011] Preferably, the rotating cylinder and the diverting cylinder are connected by a sealing assembly, which includes a fixing ring fixedly fitted onto the side wall of the diverting cylinder. A connecting ring is fixedly connected to the end face of the fixing ring, and the rotating cylinder is inserted into the connecting ring. Sealing cotton is adhered to the inner wall of the connecting ring, and the sealing cotton fills and seals the space between the inner wall of the connecting ring and the outer wall of the rotating cylinder. An air inlet and an air outlet are respectively provided on the side wall of the connecting ring. In this scheme, the space between the rotating cylinder and the diverting cylinder is sealed by the fixing ring, the connecting ring, and the sealing cotton, and inert gas can be injected into the sealed space through the air inlet and the air outlet to ensure the purity of the liquid obtained by distillation.

[0012] Preferably, an outer annular groove and an inner annular groove are respectively formed on the end face of the diverter. The outer annular groove and the inner annular groove are located on the outer and inner sides of the hole, respectively. A leakage hole is formed in both the outer annular groove and the inner annular groove, and a leakage pipe is installed in the leakage hole. In this scheme, when the distilled liquid flows out from the gap between the main pipe and the connecting pipe, it can be finally collected through the leakage pipe in the outer annular groove and the inner annular groove, thus avoiding pollution.

[0013] Preferably, the positioning component includes a positioning ring, which is fixedly sleeved on the side wall of the main flow pipe opposite to the diverter cylinder. Two positioning balls are rotatably mounted on the end face of the positioning ring, and the two positioning balls correspond to the outer annular groove and the inner annular groove, respectively. In this scheme, by having the two positioning balls respectively engage with the outer annular groove and the inner annular groove, it is ensured that the rotating cylinder will not deviate during rotation.

[0014] Preferably, the reaction device, the reflux device, the vacuum distillation device, and the sealing assembly are all connected to an inert gas storage tank and a waste gas recovery tank via pipe fittings; in this scheme, inert gas is injected into the reaction device, the reflux device, the vacuum distillation device, and the sealing assembly through the inert gas storage tank to ensure the purity of the finished product obtained during the purification process.

[0015] A process for purifying trimethylaluminum using a trimethylaluminum apparatus includes the following steps:

[0016] A. Under inert gas protection, add crude trimethylaluminum containing impurities such as oxygen and chlorine to the reaction apparatus, take a sample for testing, then turn on the reflux device and start stirring;

[0017] B. Slowly add high-purity triethylaluminum dropwise into the reaction apparatus. After the addition is complete, slowly raise the temperature to 90~130℃ and stir for 3~6 hours.

[0018] C. After the stirring reaction is complete, turn off the reflux device, turn on the vacuum distillation device, and start vacuum distillation;

[0019] D. In the process of vacuum distillation, the liquid obtained by vacuum distillation is split by a splitting assembly to obtain the fore fraction, the middle fraction and the back fraction respectively.

[0020] E. Sample and test the middle fraction obtained in step D.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] 1. By adding high-purity triethylaluminum to crude trimethylaluminum containing dimethylaluminum chloride, trimethylaluminum and diethylaluminum chloride can be obtained after the reaction. Trimethylaluminum and diethylaluminum chloride can be separated by distillation to obtain pure trimethylaluminum, thus achieving the purification of crude trimethylaluminum.

[0023] 2. During the distillation of trimethylaluminum after the reaction, a flow divider can be used to separate the liquid obtained during the temperature rise from the liquid under stable temperature conditions, which can further ensure the purity of trimethylaluminum.

[0024] 3. By having two positioning balls on the positioning ring engage with the outer and inner ring grooves respectively, it is ensured that the main pipe will not deviate during the rotation of the rotating cylinder and the diversion cylinder, and that it will be precisely connected with the corresponding pipe to avoid waste.

[0025] 4. After the main pipe and the pipes in the distribution cylinder are connected, if there is any liquid leaking from the gaps in the pipes, it can be collected through the leakage pipes installed in the outer and inner ring grooves to avoid contamination. Attached Figure Description

[0026] Figure 1 This is a connection diagram of the device of the present invention;

[0027] Figure 2 This is a schematic diagram of the flow diversion device in this invention;

[0028] Figure 3 This is a cross-sectional schematic diagram of the diversion device in this invention;

[0029] Figure 4 In this invention Figure 3 Enlarged view of point A;

[0030] Figure 5 In this invention Figure 3 Left view of the inner flow divider;

[0031] Figure 6 In this invention Figure 3 Right view of the inner rotating cylinder;

[0032] Figure 7 This is an ion chromatography chromatogram of crude trimethylaluminum in Example 3 of the present invention;

[0033] Figure 8 This is an ion chromatography chromatogram of the purified trimethylaluminum product in Example 3 of the present invention;

[0034] Figure 9 The above is the 1H NMR spectrum of crude trimethylaluminum in Example 3 of this invention;

[0035] Figure 10 This is the 1H NMR spectrum of the purified trimethylaluminum product in Example 3 of the present invention.

[0036] In the picture:

[0037] 1. Reaction apparatus; 2. Reflux apparatus; 3. Vacuum distillation apparatus; 4. Diverter;

[0038] 41. Rotating assembly; 411. Rotary motor; 412. Rotating rod; 413. Driving wheel; 414. Driven wheel;

[0039] 42. Rotating cylinder; 43. Main flow pipe;

[0040] 44. Sealing assembly; 441. Retaining ring; 442. Connecting ring; 443. Sealing cotton; 444. Air inlet; 445. Air outlet;

[0041] 45. Diverter assembly; 451. Diverter tube; 452. Fore-distillate pipe; 453. Middle-distillate pipe; 454. Back-distillate pipe; 455. Waste pipe; 456. Outer annular groove; 457. Inner annular groove; 458. Drain hole; 459. Drain pipe;

[0042] 46. ​​Positioning component; 461. Positioning ring; 462. Positioning ball;

[0043] 5. Inert gas storage tank; 6. Waste gas recovery tank; 7. First inlet; 8. Second inlet; 9. Connecting pipe; 10. Diverting pipe. Detailed Implementation

[0044] 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 embodiments of the present invention, and not all embodiments.

[0045] The components of the embodiments of the invention described and shown in the accompanying drawings can typically be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.

[0046] 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.

[0047] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0048] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0049] Please see Figure 1-6 The present invention provides a technical solution: a trimethylaluminum purification device, comprising a reaction device 1, a reflux device 2, and a vacuum distillation device 3. The reaction device 1 is connected to the reflux device 2 and the vacuum distillation device 3 respectively via pipe connectors. A flow divider 4 is connected to the vacuum distillation device 3 via pipe connectors. The flow divider 4 includes a rotating cylinder 42, a rotating component 41 connected to the side wall of the rotating cylinder 42, and a main flow pipe 43 installed inside the rotating cylinder 42. One end of the main flow pipe 43 is connected to the vacuum distillation device 3 via a diverting pipe 10, and the other end of the main flow pipe 43 is positioned and connected to the flow divider 45 via a positioning component 46.

[0050] Furthermore, the reaction device 1, reflux device 2, vacuum distillation device 3, and sealing assembly 44 are all connected to an inert gas storage tank 5 and a waste gas recovery tank 6 via pipe fittings.

[0051] Specifically, the reaction device 1 is equipped with a first inlet 7 and a second inlet 8. The first inlet 7 is connected to a crude trimethylaluminum storage tank, and crude trimethylaluminum is added into the reaction device 1 through the first inlet 7. The second inlet 8 is connected to a high-purity triethylaluminum storage tank, and high-purity triethylaluminum is slowly added dropwise into the reaction device 1.

[0052] Before the process begins, inert gas is injected into the reaction device 1, reflux device 2, vacuum distillation device 3 and sealing assembly 44 through inert gas storage tank 5 to ensure that the entire process can be carried out under the protection of inert gas. The exhaust gas discharged during this process is recovered through exhaust gas recovery tank 6.

[0053] The pipe connection between the vacuum distillation unit 3 and the diversion unit 4 is denoted as connecting pipe 9. The centerline of the main pipe 43 coincides with the centerline of the pipe it connects to. Figure 2 As shown, the upper end of the main pipe 43 is connected to the steering pipe 10. The other end of the steering pipe 10 and the connecting pipe 9 (the connecting pipe 9 is inserted into the steering pipe 10, and the diameter of the connecting pipe 9 is smaller than the inlet diameter of the steering pipe 10) are also connected by the sealing assembly 44 to ensure the sealing between the connecting pipe 9 and the steering pipe 10. In addition, the axis of the connecting pipe 9, the axis of the inlet end of the steering pipe 10 and the axis of the rotating cylinder 42 coincide, ensuring that the rotating cylinder 42 can rotate with the connecting pipe 9 as the axis. The axis of the outlet end of the steering pipe 10 coincides with the axis of the main pipe 43.

[0054] Furthermore, the diversion assembly 45 includes a diversion cylinder 451, which has several holes. The holes are evenly arranged around the axis of the diversion cylinder 451. Rotating the rotating cylinder 42 causes the main flow pipe 43 to connect with the pipes installed in different holes on the diversion cylinder 451 through the positioning assembly 46 to achieve the diversion of the distilled liquid.

[0055] like Figure 5 As shown, the distributor tube 451 has four holes of the same diameter, with an included angle of 90° between each pair of holes, and they are symmetrically distributed. The four holes are respectively equipped with a front distillation pipe 452 (for the distilled liquid during the temperature rise stage), a middle distillation pipe 453 (for the distilled liquid during the temperature stabilization stage), a rear distillation pipe 454 (for the distilled liquid during the temperature fall stage), and a waste liquid pipe 455 (for discharging other liquids).

[0056] Furthermore, the rotating assembly 41 includes a rotating motor 411, the output shaft of which is connected to a rotating rod 412. A drive wheel 413 is sleeved on the side wall of the rotating rod 412, and the drive wheel 413 is connected to the rotating cylinder 42 through a driven wheel 414.

[0057] like Figure 2 As shown, both the driving wheel 413 and the driven wheel 414 are gears that mesh with each other. The driven wheel 414 is sleeved and installed on the side wall of the rotating cylinder 42. A support member is also rotatably installed on the side wall of the rotating cylinder 42. The rotating motor 411 is fixedly installed on the support member extending from the fixed ring 441.

[0058] Furthermore, the rotating cylinder 42 and the diverting cylinder 451 are connected by a sealing assembly 44. The sealing assembly 44 includes a fixing ring 441, which is fixedly sleeved on the side wall of the diverting cylinder 451. A connecting ring 442 is fixedly connected to the end face of the fixing ring 441, and the rotating cylinder 42 is inserted into the connecting ring 442.

[0059] Furthermore, sealing cotton 443 is adhered to the inner wall of the connecting ring 442. The sealing cotton 443 fills and seals the space between the inner wall of the connecting ring 442 and the outer wall of the rotating cylinder 42. An air inlet 444 and an air outlet 445 are respectively provided on the side wall of the connecting ring 442.

[0060] Specifically, the rotating cylinder 42 can rotate under the sealing protection of the sealing cotton 443; the air inlet 444 is connected to the inert gas storage tank 5, and the air outlet 445 is connected to the waste gas recovery tank 6. Inert gas is injected into the closed space between the inner wall of the connecting ring 442 and the outer wall of the rotating cylinder 42 through the inert gas storage tank 5 to ensure that the distilled liquid is protected by inert gas.

[0061] Furthermore, an outer annular groove 456 and an inner annular groove 457 are respectively provided on the end face of the flow divider 451. The outer annular groove 456 and the inner annular groove 457 are located on the outer side and the inner side of the hole, respectively (the side closer to the axis of the flow divider 451 is the inner side, and the side farther away from the axis of the flow divider 451 is the outer side). A leakage hole 458 is provided in both the outer annular groove 456 and the inner annular groove 457, and a leakage pipe 459 is installed in the leakage hole 458.

[0062] Specifically, both the outer annular groove 456 and the inner annular groove 457 are centered on the axis of the diversion cylinder 451 (which coincides with the axis of the rotating cylinder 42); both the outer annular groove 456 and the inner annular groove 457 are provided with two oppositely positioned leakage holes 458, and the leakage pipe 459 can be connected to the waste liquid storage tank.

[0063] Furthermore, the positioning component 46 includes a positioning ring 461, which is fixedly sleeved on the side wall of the main stream pipe 43 opposite to the diverter 451. Two positioning balls 462 are rotatably installed on the end face of the positioning ring 461, and the two positioning balls 462 correspond to the outer ring groove 456 and the inner ring groove 457 respectively.

[0064] like Figure 6 As shown, two positioning balls 462 are installed on the positioning ring 461. The upper positioning ball 462 corresponds to the outer ring groove 456, and the lower positioning ball 462 corresponds to the inner ring groove 457. By having the two positioning balls 462 fit into the outer ring groove 456 and the inner ring groove 457 respectively, the main pipe 43 is tightly attached to the surface of the diverter cylinder 451. The diameter of the main pipe 43 is not larger than the diameter of the pipe being connected. When the rotating cylinder 42 drives the main pipe 43 and the positioning component 46 to rotate, the positioning balls 462 slide in the outer ring groove 456 and the inner ring groove 457 to ensure that the main pipe 43 does not shift.

[0065] After the above apparatus is installed, add crude trimethylaluminum to reaction apparatus 1, turn on reflux device 2 and start stirring, slowly add high-purity triethylaluminum dropwise to reaction apparatus 1, start stirring after the dropwise addition is completed, turn off reflux device 2 after the reaction is completed, turn on vacuum distillation apparatus 3 to carry out vacuum distillation.

[0066] During the process of increasing the distillation temperature, the main stream tube 43 and the fore-distillate tube 452 are connected, and the fore-distillate liquid flows out through the fore-distillate tube 452. When the distillation temperature tends to stabilize, the connecting tube 9 can be closed first, and the rotating cylinder 42 can be controlled by the rotary motor 411 to drive the main stream tube 43 to rotate 90°, so that the main stream tube 43 is connected with the middle-distillate tube 453. Then the connecting tube 9 is opened to obtain the middle-distillate liquid (finished product). Similarly, during the process of decreasing the distillation temperature, the main stream tube 43 and the after-distillate tube 454 are connected to complete the collection of the distilled liquid.

[0067] In all of the above processes, protection is achieved using inert gases.

[0068] A process for purifying trimethylaluminum using a trimethylaluminum apparatus includes the following steps:

[0069] A. Under inert gas protection, crude trimethylaluminum containing impurities such as oxygen and chlorine is added to reaction apparatus 1, and samples are taken for analysis of the oxygen, silicon and chlorine content in the crude trimethylaluminum by nuclear magnetic resonance, ICP (inductively coupled plasma atomic emission spectrometry) and ion chromatography. Then, reflux apparatus 2 is turned on and stirring is started.

[0070] B. Slowly add high-purity triethylaluminum dropwise into reaction apparatus 1. After the addition is complete, slowly raise the temperature to 90~130℃ and stir for 3~6 hours.

[0071] C. After the stirring reaction is complete, turn off the reflux device 2, turn on the vacuum distillation device 3, and start vacuum distillation;

[0072] D. In the process of vacuum distillation, the liquid obtained by vacuum distillation is split by a splitting assembly to obtain the fore fraction, the middle fraction and the back fraction respectively.

[0073] E. Take samples of the middle fraction (finished product) obtained in step D for testing.

[0074] Specifically, all the above steps are carried out under the protection of inert gas, and the water and oxygen content of the inert gas is less than 1 ppm.

[0075] The chemical reaction involved in the above process is the reaction of dimethylaluminum chloride and triethylaluminum at high temperature to produce trimethylaluminum and diethylaluminum chloride. The specific chemical equations are as follows:

[0076]

[0077] In step B, the amount of high-purity triethylaluminum added is 1.1 to 3 times the chlorine content in trimethylaluminum, preferably 2 times;

[0078] The stirring time in step B shall not be less than 3 hours, preferably 5 hours;

[0079] The stirring temperature in step B is 90~130℃, preferably 120℃;

[0080] In step C, the pressure is controlled at 50 Torr during vacuum distillation, and only the fraction at 55~60℃ is collected;

[0081] The middle fraction (finished product) in D above was sampled and analyzed, and the product was subjected to NMR, ICP and ion chromatography tests.

[0082] Three embodiments are obtained through the above steps:

[0083] Example 1

[0084] 1. Under inert gas protection, add 810g of crude trimethylaluminum to a 1L reaction flask and take a sample to test the impurity content;

[0085] 2. Turn on reflux device 2, turn off vacuum distillation device 3, start stirring, then add high-purity triethylaluminum dropwise, slowly raise the temperature to 90°C and stir for 3 hours;

[0086] 3. After the stirring reaction is completed, turn off the reflux device 2 and turn on the vacuum distillation device 3. Control the pressure at 50 Torr and receive the fraction at 55~60℃ (through the middle fraction tube 453). Remove 3~5% of the fore fraction (through the fore fraction tube 452) and 5~10% of the after fraction (through the after fraction tube 454).

[0087] 4. The yield of this embodiment is 86.5%. The product was detected by ion chromatography with a chlorine content of 1.2 ppm, and by nuclear magnetic resonance, the oxygen peak was not detected. The organosilicon content is 0.11 ppm.

[0088] Example 2

[0089] 1. Under inert gas protection, add 810g of crude trimethylaluminum to a 1L reaction flask and take a sample to test the impurity content;

[0090] 2. Turn on the reflux device 2, turn off the vacuum distillation device 3, start stirring, then add high-purity triethylaluminum dropwise, and slowly raise the temperature to 100°C while stirring for 3 hours.

[0091] 3. After the stirring reaction is completed, turn off the reflux device 2, turn on the vacuum distillation device 3, control the pressure at 50 Torr, and receive the fraction at 55~60℃ (through the middle fraction tube 453), of which 3~5% of the fore fraction (through the fore fraction tube 452) and 5~10% of the after fraction (through the after fraction tube 454) are removed.

[0092] 4. The yield of this embodiment is 86%. The product was detected by ion chromatography with a chlorine content of 0.64 ppm, and by nuclear magnetic resonance, the oxygen peak was not detected. The organosilicon content is 0.12 ppm.

[0093] Example 3

[0094] 1. Under inert gas protection, add 810g of crude trimethylaluminum to a 1L reaction flask and take a sample to test the impurity content;

[0095] 2. Turn on reflux device 2, turn off vacuum distillation device 3, start stirring, then add high-purity triethylaluminum dropwise, slowly raise the temperature to 120°C and stir for 5 hours;

[0096] 3. After the stirring reaction is completed, turn off the reflux device 2, turn on the vacuum distillation device 3, control the pressure at 50 Torr, and receive the fraction at 55~60℃ (through the middle fraction tube 453), of which 3~5% of the fore fraction (through the fore fraction tube 452) and 5~10% of the after fraction (through the after fraction tube 454) are removed.

[0097] 4. In this embodiment, the yield was 85%. Ion chromatography analysis showed a chlorine content of 0.63 ppm, and nuclear magnetic resonance analysis showed no detectable oxygen peak (e.g., ...). Figure 10 As shown in the figure, the chemical shift of hydrogen in the methoxy group is not shown), and the organosilicon content is 0.11 ppm.

[0098] Table 1. Ion chromatography results and corresponding chlorine content of crude trimethylaluminum and purified product in Example 3.

[0099]

[0100] Note: See [link to concentration test] Figure 7 and Figure 8 Cl concentration = (detection concentration - sample blank concentration) × dilution factor / sample mass.

[0101] Table 2 shows the chlorine, oxygen, and silicon content of crude trimethylaluminum and the purified product in Example 3.

[0102]

[0103] As can be seen from the table above, the trimethylaluminum purified by the apparatus and process disclosed in this invention has high purity and the content of impurities such as chlorine, oxygen and silicon is significantly reduced.

[0104] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A trimethylaluminum purification apparatus, comprising a reaction device (1), a reflux device (2), and a vacuum distillation device (3), wherein the reaction device (1) is connected to the reflux device (2) and the vacuum distillation device (3) respectively via pipeline connectors, characterized in that: The vacuum distillation apparatus (3) is connected to a flow divider (4) via a pipe connector. The flow divider (4) includes a rotating cylinder (42). A rotating assembly (41) is connected to the side wall of the rotating cylinder (42). A main flow pipe (43) is installed inside the rotating cylinder (42). One end of the main flow pipe (43) is connected to the vacuum distillation apparatus (3) via a diverting pipe (10). The other end of the main flow pipe (43) is positioned and connected to the flow divider assembly (45) via a positioning assembly (46). The diversion assembly (45) includes a diversion cylinder (451), which has a plurality of holes. The holes are evenly arranged on the diversion cylinder (451) around the axis of the diversion cylinder (451). Rotating the rotating cylinder (42) causes the main flow pipe (43) to connect with the pipes installed in different holes on the diversion cylinder (451) through the positioning assembly (46) to realize the diversion of distilled liquid. The inlet end of the diverting pipe (10) is connected to the connecting pipe (9), which is connected to the vacuum distillation apparatus (3). The axis of the connecting pipe (9), the axis of the inlet end of the diverting pipe (10), and the axis of the rotating cylinder (42) coincide. The axis of the outlet end of the diverting pipe (10) coincides with the axis of the main stream pipe (43). The positioning component (46) includes a positioning ring (461), which is fixedly sleeved on the side wall of the main stream pipe (43) opposite to the diverting cylinder (451). Two positioning balls (462) are rotatably installed on the end face of the positioning ring (461).

2. The trimethylaluminum purification apparatus as described in claim 1, characterized in that: The rotating assembly (41) includes a rotating motor (411), the output shaft of which is connected to a rotating rod (412). A drive wheel (413) is sleeved on the side wall of the rotating rod (412), and the drive wheel (413) is connected to the rotating cylinder (42) through a driven wheel (414).

3. The trimethylaluminum purification apparatus as described in claim 1, characterized in that: The rotating cylinder (42) and the diverting cylinder (451) are connected by a sealing assembly (44). The sealing assembly (44) includes a fixing ring (441), which is fixedly sleeved on the side wall of the diverting cylinder (451). A connecting ring (442) is fixedly connected to the end face of the fixing ring (441), and the rotating cylinder (42) is inserted into the connecting ring (442). The inner wall of the connecting ring (442) is bonded with sealing cotton (443), which fills and seals the space between the inner wall of the connecting ring (442) and the outer wall of the rotating cylinder (42). The side wall of the connecting ring (442) is provided with an air inlet (444) and an air outlet (445).

4. The trimethylaluminum purification apparatus as described in claim 1, characterized in that: The end face of the diverter (451) is provided with an outer ring groove (456) and an inner ring groove (457), respectively. The outer ring groove (456) and the inner ring groove (457) are located on the outside and inside of the hole, respectively. Both the outer ring groove (456) and the inner ring groove (457) are provided with a leakage hole (458), and a leakage pipe (459) is installed in the leakage hole (458).

5. The trimethylaluminum purification apparatus as described in claim 4, characterized in that: The two positioning balls (462) correspond to the outer ring groove (456) and the inner ring groove (457) respectively.

6. The trimethylaluminum purification apparatus as described in claim 3, characterized in that: The reaction device (1), the reflux device (2), the vacuum distillation device (3) and the sealing assembly (44) are all connected to an inert gas storage tank (5) and a waste gas recovery tank (6) via pipe fittings.

7. The process of purifying trimethylaluminum using any one of claims 1-6, characterized in that, The process includes the following steps: A. Under inert gas protection, add crude trimethylaluminum containing impurities such as oxygen and chlorine to the reaction apparatus, take a sample for testing, then turn on the reflux device and start stirring; B. Slowly add high-purity triethylaluminum dropwise into the reaction apparatus. After the addition is complete, slowly raise the temperature to 90~130℃ and stir for 3~6 hours. C. After the stirring reaction is complete, turn off the reflux device, turn on the vacuum distillation device, and start vacuum distillation; D. In the process of vacuum distillation, the liquid obtained by vacuum distillation is split by a splitting assembly to obtain the fore fraction, the middle fraction and the back fraction respectively. E. Sample and test the middle fraction obtained in step D.

Images