Salt removal process for cyclopentadienyl metal complex synthesis

Abstract

This invention discloses a method and apparatus for continuous desalination during the synthesis of cyclopentadienyl metal complexes, belonging to the field of chemical synthesis. The method employs a desalination device including a reaction vessel, a transfer pump, and a filtration system. During the reaction, the reaction temperature is controlled at 20-60°C. By opening the bottom valve of the reaction vessel, the pump inlet valve, the filtration system inlet valve, and the waste discharge valve, and starting the transfer pump, the generated byproduct salts are continuously separated and discharged through the slag discharge pipe. After the reaction, the filtration-related valves are closed, and the purification system inlet valve is opened to transfer the reaction solution to the purification system. This invention achieves online continuous separation of byproduct salts during the synthesis process, avoiding the adsorption and encapsulation of products by inorganic salts and the inhibition of common ion effects, significantly improving product purity and yield, reducing product loss, eliminating the need for a separate post-reaction filtration step, shortening the production cycle, and improving process safety through a fully closed operation.

Description

Technical Field

[0001] This invention belongs to the field of organometallic compound synthesis technology, specifically relating to a desalination method in the synthesis process of cyclopentadienyl metal complexes. Background Technology

[0002] Cyclopentadienyl metal complexes are widely used as catalysts in organic synthesis reactions such as olefin polymerization, olefin cyclization, and olefin insertion reactions. They can also be used in asymmetric synthesis and as precursors. Common synthetic methods involve reacting sodium cyclopentadienyl or lithium cyclopentadienyl with metal halides in solvents such as tetrahydrofuran, ethylene glycol, n-hexane, and dimethyl ether.

[0003] Existing technologies mostly employ a one-pot batch reaction, followed by overall filtration to separate byproduct halide salts after the reaction. However, due to the extreme sensitivity of the reaction system to air and water, conventional filtration operations are difficult and time-consuming. Furthermore, byproduct salts often adsorb or encapsulate raw materials and target products in the form of fine particles, leading to reduced product yield and purity. The accumulation of byproduct salts also inhibits the main reaction, reducing the reaction rate. Summary of the Invention

[0004] The present invention aims to solve the problems of difficult separation of by-product salts, large product loss, and long auxiliary production time in the synthesis of cyclopentadienyl metal complexes in the prior art. It provides a method and apparatus for continuous separation of by-product salts in the synthesis process, so as to improve product purity and yield, reduce production costs, and enhance process safety.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a desalination method for the synthesis process of cyclopentadienyl metal complexes, which uses a desalination device for desalination. The desalination device includes a reactor, a transfer pump, and a filter. The discharge port of the reactor is connected to the transfer pump through a discharge pipe. The transfer pump is connected to a first distribution pipe and a second distribution pipe through a three-way pipe. The second distribution pipe is connected to a purification system. The first distribution pipe is connected to the filter. The filter is connected to a reflux pipe and a slag discharge pipe. The reflux pipe is connected to the reactor. A reactor bottom valve is installed at the discharge port. A pump inlet valve is installed on the discharge pipe. An inlet valve for the filter is installed on the first distribution pipe. An inlet valve for the purification system is installed on the second distribution pipe. A filtrate reflux valve is installed on the reflux pipe. A waste residue discharge valve is installed on the slag discharge pipe. The desalination method includes the following process: the temperature inside the reactor is controlled to be maintained between -20℃ and 10℃; a certain amount of cyclopentadienyl metal complex and solvent are injected into the reactor through a closed pipeline using high-purity nitrogen; then a certain amount of metal halide is added to carry out the reaction; the reaction temperature inside the reactor is controlled between 20-60℃; during the reaction, the bottom valve of the reactor, the pump inlet valve, the filter equipment inlet valve, and the filtrate reflux valve are opened; the transfer pump is turned on; the filtrate is continuously refluxed back into the reactor; and the waste salt is intermittently discharged from the slag discharge pipe by controlling the slag discharge valve. After the reaction is complete, continue full-volume filtration for 30 minutes. Then, close the inlet valve, filtrate reflux valve, and waste discharge valve of the filtration equipment, and open the bottom valve of the reaction vessel and the inlet valve of the purification system to transfer the reaction solution to the purification system for purification, thus completing the desalination process of the cyclopentadienyl metal complex synthesis.

[0006] As a preferred embodiment of the above technical solution, a flushing pipe is connected to the discharge pipe, which is connected to a solvent storage tank. A flushing valve is installed on the flushing pipe. The connection between the flushing pipe and the discharge pipe is located between the bottom valve of the reactor and the inlet valve of the pump. After the reaction is completed and the full-volume filtration is completed for 30 minutes, the bottom valve of the reactor is closed first, while the inlet valve of the filtration equipment and the filtrate return valve are kept open, and the inlet valve of the purification system is kept closed. The transfer pump is then turned on, and the solvent in the solvent storage tank is used to flush the discharge pipe, the first distribution pipe, and the return pipe. After flushing is completed, the inlet valve of the filtration equipment, the filtrate return valve, and the waste discharge valve are closed, while the bottom valve of the reactor and the inlet valve of the purification system are opened. The transfer pump is then turned on to transfer the reaction solution to the purification system for purification.

[0007] As a preferred embodiment of the above technical solution, the solvent is at least one of alkanes, ethers, and aromatic hydrocarbons, preferably n-hexane. The reaction solution is transferred to a purification system for purification, and the solvent is separated from it. The separated solvent is returned to the solvent storage tank for reuse. The cyclopentadienyl alkali metal salt includes at least one of cyclopentadienyl lithium and cyclopentadienyl sodium, and the metal halide includes at least one of titanium, zirconium, hafnium, rare earth metal chlorides, bromides, and iodides.

[0008] As a preferred embodiment of the above technical solution, the slag discharge pipe is connected to the waste slag bucket, the connection between the slag discharge pipe and the waste slag bucket is sealed, and the waste slag bucket is protected by an anhydrous inert gas atmosphere of 0.1-0.2 barg.

[0009] As a preferred embodiment of the above technical solution, the filter equipment comprises at least one of filter screen, filter bag, and sintered filter element, wherein the filter screen, filter bag, or sintered filter element has a filter diameter of 100-2000 mesh.

[0010] As a preferred embodiment of the above technical solution, the reactor is a jacketed reactor with a stirring function.

[0011] As a preferred technical solution, the desalination unit undergoes high-pressure leak testing, inert gas purging, and vacuum replacement before feeding to ensure that the unit is free of water and oxygen. Specifically, 7 bar of anhydrous inert gas is first introduced into the reactor to check for leaks in the entire desalination unit; then, 1-2 barg of anhydrous inert gas is used to purge the entire desalination unit, and a vacuum pump is used to evacuate the system to ensure that there is no residual air or water inside the unit.

[0012] The beneficial effects of this invention are: 1. By continuously separating by-product salts during the reaction process, the adsorption and encapsulation of by-product salts on raw materials and products are reduced, side reactions are decreased, and product purity and yield are improved.

[0013] 2. Remove by-product salts (such as LiCl) in a timely manner to reduce system viscosity, improve mass transfer, and shorten reaction time.

[0014] 3. By-product salts are separated immediately after generation, reducing the contact time between the product and inorganic salts, inhibiting product decomposition and discoloration, and improving product stability and shelf life.

[0015] 4. The separate filtration step after the reaction is completed is eliminated, and the product can be directly introduced into the purification system after the reaction is completed, which greatly shortens the auxiliary production time.

[0016] 5. The entire process is completed in a closed system. The separation and barreling of by-product salts are carried out under an inert atmosphere to prevent the materials from coming into contact with air and water, thereby reducing safety risks.

[0017] 6. The residual amount of products in waste salt is extremely low, which facilitates the recycling and utilization of by-product salt, achieving resource utilization and environmental protection standards. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the desalination device of the present invention; Figure 2 This is a schematic diagram of a traditional desalination device. Detailed Implementation

[0019] 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.

[0020] 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.

[0021] 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.

[0022] A method for desalting during the synthesis of cyclopentadienyl metal complexes, using the following apparatus: Figure 1 As shown.

[0023] Example 1: 1) Equipment preparation: The device is as follows Figure 1 A 100L reactor 1 with a stirrer and jacket is installed. A bottom valve V1 is installed at the bottom outlet of reactor 1, which is connected in sequence to a transfer pump 3 and a three-way pipe. One end of the three-way pipe connects to a filter device 5 via a first distribution pipe. Filter device 5 has a built-in 500-mesh filter screen. The bottom of filter device 5 is connected to a waste residue bin 4 via a slag discharge pipe, on which a waste residue discharge valve V7 is installed. The upper part of filter device 5 is connected to reactor 1 via a reflux pipe, on which a filtrate reflux valve V6 is installed. The other end of the three-way pipe connects to a purification system via a second distribution pipe, on which a purification system inlet valve V4 is installed. A flushing pipe is installed on the discharge pipe near reactor 1, connecting to a solvent storage tank, and a flushing valve V2 is installed on the flushing pipe.

[0024] First, use 7 barg of anhydrous high-purity nitrogen to check the system for leaks and confirm that there are no leaks. Then, use 1-2 barg of high-purity nitrogen to purge the pipelines and equipment, and use a vacuum pump to evacuate the system to ensure that there is no residual air inside.

[0025] 2) Reaction and desalination process: The stirring speed of the 100L reactor 1 was controlled at 200 rpm, and the temperature was controlled between -20℃ and 10℃. 7.2 kg of lithium cyclopentadiene and 43.0 kg of n-hexane were pressurized into reactor 1 through a closed pipeline using high-purity nitrogen. Within 2 hours, 19.0 kg of titanium tetrachloride was added to reactor 1 to initiate the reaction, with the reaction temperature controlled between 20-60℃.

[0026] During the reaction, open the reactor bottom valve V1, pump inlet valve V3, filter inlet valve V5, filtrate reflux valve V6, and waste discharge valve V7, and start the transfer pump 3. The reaction liquid carries the generated waste salt (mainly LiCl) into the filter 5. After being intercepted by a 500-mesh filter screen, the waste salt is discharged into the waste residue bin 4 through the slag discharge pipe. The filtrate returns to the reactor 1 through the reflux pipe. The waste residue bin 4 is sealed to the slag discharge pipe and is protected with 0.1-0.2 barg of high-purity nitrogen.

[0027] Waste salt is continuously separated during the reaction until the reaction is complete.

[0028] 3) Post-processing: After the reaction is complete, continue full-volume circulation filtration for 30 minutes, then close the bottom valve V1 of the reactor, keep the inlet valve V5 of the filtration equipment and the filtrate reflux valve V6 open, close the inlet valve V4 of the purification system, open the flushing valve V2, start the transfer pump 3, and flush the discharge pipe, the first distribution pipe and the reflux pipe with n-hexane from the solvent storage tank to avoid pipe blockage and product residue.

[0029] After rinsing, close the inlet valve V5 of the filtration equipment, the filtrate reflux valve V6, and the waste discharge valve V7. Open the bottom valve V1 of the reaction vessel and the inlet valve V4 of the purification system, and start the transfer pump 3 to transfer all the reaction solution to the purification system. The purification system uses low-temperature recrystallization + distillation to recover and recycle n-hexane, while obtaining a high-purity cyclopentadienyl metal complex product.

[0030] After purification, 19.77 kg of product was obtained, with a yield of 90.26% and a purity of 99.68%; 9.22 kg of filter residue was obtained, which contained 1.14 kg of product.

[0031] Comparative Example 1) Equipment preparation: The device is as follows Figure 2A 100L reactor 1 with a stirrer and jacket is provided. A bottom valve V1 is installed at the bottom outlet of reactor 1. A control valve V2 is installed on the inlet pipe of the transfer pump 3. The material pipe is connected to the filter equipment 5, and a control valve V4 is installed on the pipeline. The filter equipment 5 has a built-in 500-mesh filter screen. The bottom of the filter equipment 5 is connected to the waste residue bucket 4 through the slag discharge pipe, and a waste residue discharge valve V6 is installed on the slag discharge pipe. The filter equipment 5 is connected to the purification system through a material pipe, and a control valve V5 is installed on the pipeline. A flushing pipe is installed on the side of the discharge pipe of reactor 1 near reactor 1. The flushing pipe is connected to the solvent storage tank, and a flushing valve V2 is installed on the flushing pipe.

[0032] First, use 7 barg of anhydrous high-purity nitrogen to check the system for leaks and confirm that there are no leaks. Then, use 1-2 barg of high-purity nitrogen to purge the pipelines and equipment, and use a vacuum pump to evacuate the system to ensure that there is no residual air inside.

[0033] 2) Reaction and desalination process: The stirring speed of the 100L reactor 1 was controlled at 200 rpm, and the temperature was controlled between -20℃ and 10℃. 7.2 kg of lithium cyclopentadiene and 43.0 kg of n-hexane were pressurized into reactor 1 through a closed pipeline using high-purity nitrogen. Within 2 hours, 19.0 kg of titanium tetrachloride was added to reactor 1 to initiate the reaction, with the reaction temperature controlled between 20-60℃ until the reaction was complete.

[0034] 3) Post-processing: After the reaction is complete, open the reactor bottom valve V1, pump inlet valve V3, filter inlet valve V4, filtrate outlet valve V5, and slag discharge valve V6, and start the transfer pump 3 to transfer all the reaction solution to the purification system. After the reactor is empty, close the reactor bottom valve V1 and open the flushing valve V2 to flush the pipeline with solvent. After flushing, close all valves and the transfer pump. The purification system uses low-temperature recrystallization + distillation to recover and recycle n-hexane, while simultaneously obtaining a high-purity cyclopentadienyl metal complex product.

[0035] After purification, 17.82 kg of product was obtained, with a yield of 81.36% and a purity of 99.34%; 11.99 kg of filter residue was obtained, which contained 2.13 kg of product.

[0036] Example 2 Same as in Example 1, but with the filter replaced by a 1500 mesh screen for the experiment.

[0037] After purification, 18.54 kg of product was obtained, with a yield of 84.22% and a purity of 99.51%; 10.34 kg of filter residue was obtained, of which 1.74 kg contained product.

[0038] Example 3 Same as in Example 1, but with the filter replaced by a 300-mesh filter for the experiment.

[0039] After purification, 18.65 kg of product was obtained, with a yield of 85.17% and a purity of 99.55%; 11.07 kg of filter residue was obtained, of which 1.96 kg contained product.

[0040] The reason why this invention can achieve the above-mentioned technical effects is: Because the synthesis of cyclopentadienyl metal complexes involves long reaction times and low temperatures, byproduct salts adsorb and encapsulate raw material and product molecules in the form of fine particles. This leads to increased side reactions, decreased product purity, and reduced activity in catalytic reactions (such as olefin polymerization), thus affecting its application in the semiconductor industry. Furthermore, the adsorbed and encapsulated products are difficult to separate during filtration, resulting in product loss.

[0041] Some by-product salts may undergo weak coordination or electron transfer with the product, altering its electronic structure, reducing product stability, and decreasing product purity.

[0042] In addition, the accumulation of by-product salts can inhibit the reaction. Taking the reaction (CpLi+TiCl4→CpTiCl3+LiCl) in the example as an example, if the by-product salt LiCl is not separated in time, the viscosity of the system will increase, the mass transfer efficiency will decrease significantly, the reaction rate will be reduced, and the local salting-out of the material will further prolong the reaction time, affecting the production efficiency.

[0043] Separating byproduct salts during the reaction process can reduce the adsorption and encapsulation of product molecules by byproduct salts, improve product purity, and reduce product loss; at the same time, it can reduce the contact time between byproduct salts and products, reduce side reactions, and improve the conversion rate of raw materials and the yield of products.

[0044] Traditional filtration is carried out after the reaction is complete. Due to the physical properties of inorganic salts, a filter bag precision filter is generally used. Separating and packing the waste salt into containers is difficult, and a large amount of residual products remain in the waste liquid. These products are highly reactive when exposed to water or air, posing a significant safety risk.

[0045] During the reaction, by-product salts are separated. The by-product salts contain a small amount of product, and the separated by-product salts can be recycled and reused through steps such as water washing. Furthermore, the by-products are separated and packed into containers in a closed system, and inert gas is used to blow air through the joints to further enhance safety.

[0046] In addition, by-product salts are separated during the reaction process, reducing auxiliary production time (filtration), simplifying production steps, shortening the residence time of the reaction solution in the system, and allowing for direct purification steps such as distillation after the reaction, thus shortening production time and reducing production costs.

[0047] It is worth mentioning that the technical features of the reaction vessel, transfer pump, etc. involved in this patent application should be regarded as prior art. The specific structure, working principle, and possible control methods and spatial arrangement of these technical features can be adopted using conventional choices in the field, and should not be regarded as the inventive point of this patent. This patent will not be further elaborated in detail.

[0048] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make many modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning or limited experimentation on the basis of the prior art should be within the scope of protection defined by the claims.

Claims

1. A method for desalting during the synthesis of cyclopentadienyl metal complexes, characterized in that, Desalination is performed using a desalination device. The desalination device includes a reactor, a transfer pump, and a filter. The discharge port of the reactor is connected to the transfer pump through a discharge pipe. The transfer pump is connected to a first distribution pipe and a second distribution pipe through a three-way pipe. The second distribution pipe is connected to a purification system. The first distribution pipe is connected to the filter. The filter is connected to a reflux pipe and a slag discharge pipe. The reflux pipe is connected to the reactor. A reactor bottom valve is installed at the discharge port. A pump inlet valve is installed on the discharge pipe. An inlet valve for the filter is installed on the first distribution pipe. An inlet valve for the purification system is installed on the second distribution pipe. A filtrate reflux valve is installed on the reflux pipe. A waste residue discharge valve is installed on the slag discharge pipe. The desalination method includes the following process: the temperature inside the reactor is controlled to be maintained between -20℃ and 10℃; a certain amount of cyclopentadienyl alkali metal salt and solvent are injected into the reactor through a closed pipeline using high-purity nitrogen; then a certain amount of metal halide is added to react; the reaction temperature inside the reactor is controlled between 20-60℃; during the reaction, the bottom valve of the reactor, the pump inlet valve, the filter equipment inlet valve, and the filtrate reflux valve are opened; the transfer pump is turned on; the filtrate is continuously refluxed back to the reactor; and the waste salt is intermittently discharged from the slag discharge pipe through the slag discharge valve. After the reaction is complete, after full circulation filtration for 30 minutes, close the inlet valve, filtrate reflux valve and waste discharge valve of the filtration equipment, open the bottom valve of the reaction vessel and the inlet valve of the purification system, and transfer the reaction solution to the purification system for purification to complete the desalination process of cyclopentadienyl metal complex synthesis.

2. The desalination method for the synthesis process of cyclopentadienyl metal complexes as described in claim 1, characterized in that, A flushing pipe is connected to the discharge pipe, which is connected to a solvent storage tank containing flushing solvent. A flushing valve is installed on the flushing pipe. The connection between the flushing pipe and the discharge pipe is located between the bottom valve of the reactor and the inlet valve of the pump. After the reaction is completed and the full-volume circulation filtration is performed for 30 minutes, the bottom valve of the reactor is closed first, while the inlet valve of the filtration equipment and the filtrate return valve are kept open, and the inlet valve of the purification system is kept closed. The transfer pump is then turned on, and the flushing solvent in the solvent storage tank is used to flush the discharge pipe, the first distribution pipe, and the return pipe. After flushing is completed, the inlet valve of the filtration equipment, the filtrate return valve, and the waste discharge valve are closed, while the bottom valve of the reactor and the inlet valve of the purification system are opened. The transfer pump is then turned on to transfer the reaction solution to the purification system for purification.

3. The desalination method for the synthesis process of cyclopentadienyl metal complexes as described in claim 2, characterized in that, The rinsing solvent is at least one of alkanes, ethers, and aromatic hydrocarbons. After the reaction solution is transferred to the purification system for purification, the solvent is separated and returned to the solvent storage tank for reuse.

4. The desalination method for the synthesis process of cyclopentadienyl metal complexes as described in claim 1, characterized in that, The slag discharge pipe is connected to the waste slag bucket. The connection between the slag discharge pipe and the waste slag bucket is sealed, and an inert gas is used to isolate and protect the waste slag.

5. The method as described in claim 1, characterized in that, The filtration equipment includes at least one of filter screen, filter bag, and sintered filter element, and the filter diameter of the filter screen, filter bag, or sintered filter element is 100-2000 mesh.

6. The desalination method for the synthesis process of cyclopentadienyl metal complexes as described in claim 1, characterized in that, The reactor is a jacketed reactor with a stirring function.

7. The method as described in claim 1, characterized in that, Before feeding, the inside of the desalination device is subjected to high-pressure leak testing, inert gas purging, and vacuum replacement in sequence to ensure that the inside of the desalination device is free of water and oxygen.

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