System and method for preparing homogeneous metallocene catalyst

Abstract

Provided are a system and method for preparing a homogeneous metallocene catalyst. The system comprises a homogeneous metallocene catalyst synthesis unit, a solvent condensation and collection unit, and a gas purification unit. The method comprises: adding a solid metallocene ligand and a solvent to a fluidized bed reactor (1), introducing a protective gas, and spraying a metal ion solution, so as to generate a homogeneous metallocene catalyst; allowing the protective gas to entrain the solvent into a condenser (4); and then enabling the protective gas to enter a fluidized bed gas purifier (5). Double fluidized beds are utilized to complete the synthesis of the homogeneous metallocene catalyst and the purification of the gas, thereby reducing the contents of water and oxygen in the atmosphere of the reaction process of the metallocene ligand and metal ions, and also increasing the conversion rate of an active center during the reaction process.

Description

A homogeneous metallocene catalyst preparation system and method Technical Field

[0001] The present invention relates to the technical field of homogeneous metallocene catalysts, and in particular to a homogeneous metallocene catalyst preparation system and method. Background Art

[0002] Homogeneous metallocene catalyst systems utilize a pentadentate coordination complex formed between cyclopentadiene and its derivatives (such as indene and fluorene) and a Group IVB transition metal (such as titanium and zirconium) as the main catalyst, with methylaluminoxane (MAO) or an organoboron compound as a cocatalyst. Compared to traditional Ziegler-Natta catalysts, metallocene complexes as the main catalyst offer more precise controllability, primarily due to the structure of the metallocene ligand. On the one hand, the metallocene ligand complexes the Group IV metal to form a single active center; on the other hand, the metallocene ligand regulates the spatial geometry surrounding the single active center, thereby regulating the coordinated insertion of olefin molecules into the active center for chain growth reactions, thereby producing polymers with high stereoregularity.

[0003] Despite the many advantages mentioned above, homogeneous metallocene catalysts also have some shortcomings that need to be overcome: (1) Homogeneous metallocene catalysts (in this case, the metallocene complex used as the main catalyst) are extremely sensitive to water and oxygen, and the synthesis conditions are extremely harsh; (2) During the preparation of homogeneous metallocene catalysts, the reaction conversion rate of metal ions and ligands is low, resulting in low catalyst synthesis efficiency; (3) Homogeneous metallocene catalysts with complex molecular structures have many synthesis steps, a long reaction process, and complex by-products, so the separation of the catalyst and the recovery and regeneration of the solvent are very difficult.

[0004] In the prior art, the preparation of homogeneous metallocene catalysts is still at the laboratory stage. Conventionally, all synthesis and processing related to metallocene complexes and sensitive substances are performed using the standard Schlenk anhydrous and oxygen-free technique. This anhydrous and oxygen-free technique uses high-purity nitrogen as the protective gas through a double-row tube for standard operation. Special operation requirements require operation in a glove box. All glassware used in the experiment must be vacuum-baked under a gas lamp and cooled to room temperature before use. All anhydrous solvents used in the experiment must undergo special treatment before use. For example, aprotic solvents such as anhydrous tetrahydrofuran, anhydrous toluene, and anhydrous ether must be added with sodium metal and benzophenone under a high-purity nitrogen atmosphere, refluxed until purple-red, and then distilled into an ampoule filled with 4A molecular sieves for storage. For another example, anhydrous n-pentane, n-hexane, and dichloromethane must be added with an appropriate amount of calcium hydride under a protective gas atmosphere, stirred for 2-3 days, and then distilled into an ampoule filled with 4A molecular sieves for storage.

[0005] CN210058286U discloses a catalyst system preparation device. The device comprises a preparation kettle, a feed tank, a gas injection line, a liquid injection line, a liquid level control unit, and a pressure control unit. This device improves the controllability of the complexation reaction between the gaseous catalyst and the liquid promoter, and enhances the quality of the catalyst system. The feed tank is located above the preparation kettle, allowing the promoter in the feed tank to automatically flow into the preparation kettle, eliminating the need for external energy and saving energy.

[0006] CN204224504U discloses a metallocene catalyst preparation device for producing low-crystal-point polyethylene. The device includes an aluminum alkyl preparation tank, which is sequentially connected to a flow-restricting orifice plate, an aluminum alkyl feed injector, and a catalyst carrier preparation tank. By adding a flow-restricting orifice plate to the pipeline, the device can control the aluminum alkyl feed rate. By adding an aluminum alkyl feed injector to the pipeline, the device ensures a uniform reaction between the aluminum alkyl and silica gel, resulting in a uniform carrier and improving catalyst performance.

[0007] CN112745404A discloses a metallocene catalyst composition and a method for preparing polyolefin elastomers using the same. The metallocene catalyst composition comprises a metallocene compound having a single active center and a cocatalyst. When the metallocene catalyst composition is used for the copolymerization of ethylene and 1-octene, the catalyst activity is greater than 1×10 6 g(mPE) / mol(cat)·h, and the density of the obtained polyolefin elastomer is 0.865-0.935g / cm 3 The number average molecular weight is between 104 and 106 Daltons, and the molecular weight distribution is 1.2 to 8.5.

[0008] EP0416815A2 discloses a metallocene catalyst and its preparation method. This catalyst replaces one Cp ring in a conventional organometallic compound containing two Cp rings with a heteroatom N, and connects the other Cp ring to the N atom via a Si bridge group, forming a four-membered ring structure with geometric tension. This four-membered ring structure restricts the free rotation of the Cp ring around the metal center, imparting structural rigidity to the catalyst. Furthermore, the lack of steric hindrance increases the openness of the metal active center, thereby improving the insertion rate of long-chain α-olefin comonomers.

[0009] However, none of the aforementioned existing technologies address the low ion reaction conversion rate and high water-oxygen sensitivity during the preparation of homogeneous metallocene catalysts. Therefore, developing a novel homogeneous metallocene catalyst preparation system and method remains a pressing issue in the field.

[0010] Summary of the Invention

[0011] To address the above-mentioned technical problems, the present invention provides a homogeneous metallocene catalyst preparation system and method. This system utilizes a dual fluidized bed to synthesize the homogeneous metallocene catalyst and purify the gas. This reduces the water and oxygen content in the atmosphere during the chemical reaction between the metallocene ligand and the metal ion, while also increasing the conversion rate of the active center during the chemical reaction.

[0012] In order to achieve the above object, the first aspect of the present invention provides a homogeneous metallocene catalyst preparation system, which at least comprises: a homogeneous metallocene catalyst synthesis unit, a solvent condensation and collection unit, and a gas purification unit;

[0013] Wherein, the homogeneous metallocene catalyst synthesis unit includes a fluidized bed reactor and a temperature and pressure detection component; the fluidized bed reactor includes a reactor shell, an air inlet, an air outlet, a metallocene ligand feed port, a metal ion solution feed port, a solvent feed port, a discharge port, and a nozzle; the air inlet and the discharge port are arranged at the lower part of the reactor shell; the metallocene ligand feed port, the metal ion solution feed port, and the solvent feed port are arranged on the side wall of the reactor shell; the air outlet is arranged at the top of the reactor shell; the nozzle is arranged on the inner wall of the reactor shell; the nozzle is connected to the metal ion solution feed port; the temperature and pressure detection component is arranged at the top of the reactor shell, for detecting the temperature and pressure inside the reactor shell;

[0014] The solvent condensation and collection unit includes a condenser; the condenser is provided with at least a condensation medium inlet, a condensation medium outlet, an air inlet, an air outlet, and a solvent outlet; the condensation medium inlet is provided at the lower part of the condenser, the condensation medium outlet is provided at the upper part of the condenser, the air inlet is provided at the upper part of the condenser, the air outlet is provided at the top of the condenser, and the solvent outlet is provided at the bottom of the condenser;

[0015] The gas purification unit includes a fluidized bed gas purifier; the fluidized bed gas purifier includes a purifier housing, an air inlet, and an air outlet; the air inlet is arranged at the lower part of the purifier housing; the air outlet is arranged at the top of the purifier housing; the interior of the purifier housing has adsorbent particles;

[0016] The gas outlet of the fluidized bed reactor is connected to the gas inlet of the condenser through a pipeline;

[0017] The gas outlet of the condenser is connected to the gas inlet of the fluidized bed gas purifier through a pipeline;

[0018] The gas outlet of the fluidized bed gas purifier is connected to the gas inlet of the fluidized bed reactor through a pipeline.

[0019] In the above-mentioned homogeneous metallocene catalyst preparation system, preferably, the homogeneous metallocene catalyst synthesis unit and the gas purification unit further include: a material level detection component, and the material level detection component is respectively arranged inside the reactor shell and inside the purifier shell.

[0020] In the above-mentioned homogeneous metallocene catalyst preparation system, preferably, the gas purification unit further comprises a gas impurity detection component, which is arranged at the gas outlet of the fluidized bed gas purifier.

[0021] In the above-mentioned homogeneous metallocene catalyst preparation system, preferably, in the fluidized bed reactor, the number of the nozzles is one or more, all of which are disposed on the inner wall of the reactor shell. It will be appreciated by those skilled in the art that, when multiple nozzles are provided, the number of the metal ion solution feed ports is also multiple, each of which is connected to the multiple nozzles.

[0022] In the above-described homogeneous metallocene catalyst preparation system, preferably, a gas distributor is further provided within the fluidized bed reactor, the gas distributor being located above the gas inlet of the fluidized bed reactor. The gas distributor employed is a conventional device in the art, and the present invention is not particularly limited to its specific structure.

[0023] In the above-mentioned homogeneous metallocene catalyst preparation system, preferably, a compressor is provided on the pipeline connecting the gas outlet of the fluidized bed gas purifier and the gas inlet of the fluidized bed reactor.

[0024] In the above-mentioned homogeneous metallocene catalyst preparation system, preferably, the condenser comprises a shell-and-tube condenser. More preferably, the condenser comprises a condenser shell, a plurality of heat exchange tubes, and a plurality of baffles, wherein the plurality of heat exchange tubes and the plurality of baffles are disposed within the condenser shell, the condensing medium inlet and the condensing medium outlet are connected to the plurality of heat exchange tubes, and the plurality of baffles are staggered along a vertical direction of the condenser shell.

[0025] In the above homogeneous metallocene catalyst preparation system, preferably, a pressure relief valve is provided on the top of the condenser.

[0026] In the above-mentioned homogeneous metallocene catalyst preparation system, preferably, a gas supply port is provided on the side wall of the condenser.

[0027] In the present invention, the air supply port and pressure relief valve of the condenser can control the pressure of the system, and can replenish pressure or release pressure for the system, thereby avoiding accidents caused by abnormal working conditions such as excessive system pressure and incomplete condensation.

[0028] In the above-described homogeneous metallocene catalyst preparation system, a solution concentration detector is preferably provided at the solvent outlet of the condenser. The solution concentration detector is used to detect the concentration and composition of the liquid discharged from the solvent outlet of the condenser. The solution concentration detector employed can be a conventional device in the art, and the present invention is not particularly limited to its specific structure.

[0029] In the above-mentioned homogeneous metallocene catalyst preparation system, preferably, the plurality of baffles in the condenser form a baffle group that is in a broken line shape in the vertical direction.

[0030] In the above-mentioned homogeneous metallocene catalyst preparation system, the adsorbent particles within the purifier housing are particles capable of adsorbing water and oxygen. Preferably, the adsorbent comprises a molecular sieve. Specifically, the molecular sieve comprises one or a combination of 5A molecular sieve, 3A molecular sieve, 4A molecular sieve, and 13X molecular sieve.

[0031] In the above-mentioned homogeneous metallocene catalyst preparation system, preferably, the gas purification unit further comprises: an initial protective gas delivery pipeline, which is connected to the air inlet of the fluidized bed gas purifier and is used to provide initial protective gas to the system.

[0032] In the above-mentioned homogeneous metallocene catalyst preparation system, preferably, the gas impurity detection component includes a gas chromatograph and an online sampling probe thereof.

[0033] In the above-mentioned homogeneous metallocene catalyst preparation system, preferably, the gas purification unit further includes: a protective gas return pipeline, one end of which is connected to the gas impurity detection component, and the other end is connected to the air inlet of the fluidized bed gas purifier, so as to allow the protective gas whose water and oxygen content does not meet the requirements after detection by the gas impurity detection component to re-enter the fluidized bed gas purifier for purification.

[0034] In the above-described homogeneous metallocene catalyst preparation system, preferably, a gas distributor is further provided within the fluidized bed gas purifier, the gas distributor being located above the gas inlet of the fluidized bed gas purifier. The gas distributor employed is a conventional device in the art, and the present invention is not particularly limited to its specific structure.

[0035] In the above-mentioned homogeneous metallocene catalyst preparation system, preferably, the solvent outlet of the condenser is connected to the solvent feed inlet of the fluidized bed reactor through a pipeline.

[0036] In the above-mentioned homogeneous metallocene catalyst preparation system, the temperature and pressure detection components, the material level detection component in the homogeneous metallocene catalyst synthesis unit, and the material level detection component in the gas purification unit are all conventional devices in the field, and the present invention does not specifically limit their specific structures.

[0037] According to a specific embodiment of the present invention, preferably, the above system further comprises: a ligand synthesis unit for synthesizing the cyclopentadienyl ligand. The ligand synthesis unit can adopt a ligand synthesis device in the prior art, and the present invention does not specifically limit its structure.

[0038] According to a specific embodiment of the present invention, the system preferably further includes a recrystallization unit for recrystallizing and purifying the cyclopentadienyl ligand synthesized in the ligand synthesis unit. The recrystallization unit can be operated using conventional equipment and is not particularly limited in the present invention. The recrystallization unit can be connected to the cyclopentadienyl ligand feed port of the fluidized bed reactor via a pipeline.

[0039] According to a specific embodiment of the present invention, preferably, the above-mentioned system further includes: a raw material storage unit, wherein the raw material storage unit includes a storage device for raw materials for synthesizing ligands, a storage device for metal ion solution, and a storage device for solvent; the storage device for raw materials for synthesizing ligands is connected to the ligand synthesis unit; the storage device for metal ion solution is connected to the metal ion solution feed port of the fluidized bed reactor, and the storage device for solvent is connected to the solvent feed port of the fluidized bed reactor. These storage devices can all adopt storage devices in the prior art and are not particularly limited in the present invention.

[0040] According to a specific embodiment of the present invention, the system preferably further includes a raw material refining unit connected to the raw material storage unit and configured to refine raw materials for synthesizing the ligand, raw materials for synthesizing the metal ion solution, and solvent. The raw material refining unit can employ a raw material refining device known in the art, and the present invention does not impose any particular limitation on its structure.

[0041] According to a specific embodiment of the present invention, preferably, the above-mentioned system further includes: a solvent recovery unit, which is connected to the solvent outlet of the condenser through a pipeline for recovering the solvent. The recovered solvent can be returned to the above-mentioned raw material refining unit and raw material storage unit, and then returned to the homogeneous metallocene catalyst synthesis unit to achieve the reuse of the solvent. It will be understood by those skilled in the art that the solvent recovered by the solvent recovery unit includes the solvent in the metal ion solution and the solvent entering the system from the solvent feed port of the fluidized bed reactor. In addition, it will be understood by those skilled in the art that when the system of the present invention does not include a solvent recovery unit, as described above, the solvent outlet of the condenser can be directly connected to the solvent feed port of the fluidized bed reactor through a pipeline.

[0042] According to a specific embodiment of the present invention, preferably, the above system further comprises: a catalyst storage unit, which is connected to the discharge port of the fluidized bed reactor through a pipeline and is used to store the prepared homogeneous metallocene catalyst.

[0043] In the present invention, a fluidized bed refers to a process in which a large number of solid particles are suspended in a moving fluid, so that the particles have certain apparent characteristics of the fluid. Specifically, when the speed of the fluid passing through the bed gradually increases to a certain value, the particles become loose, the gaps between the particles increase, and the volume of the bed expands. If the fluid speed is further increased, the bed will no longer be able to maintain a fixed state. At this point, all the particles are suspended in the fluid, showing quite irregular movement. As the flow rate increases, the movement of the particles becomes more intense, and the expansion of the bed also increases accordingly, but the particles still remain in the bed and are not carried out by the fluid. At this point, the state of the bed is similar to that of a liquid. This fluid-solid contact state is called solid fluidization, or fluidized bed.

[0044] A fully fluidized bed exhibits properties similar to those of a liquid. The fluidized bed of the present invention has the following characteristics: fluids with a density less than the average density of the bed can be suspended on the bed surface; the bed surface remains horizontal; the bed obeys the hydrostatic law, namely, the pressure difference Δp = ρgL across two sections with a height difference of L; the particles exhibit fluidity similar to that of a liquid; there is dispersed fluidization; and the two interconnected fluidized beds employed in the present invention can automatically adjust the upper surfaces of the beds to the same level.

[0045] The homogeneous metallocene catalyst preparation system provided by the present invention uses a dual fluidized bed to complete the synthesis of the homogeneous metallocene catalyst and the purification of the gas. During the catalyst synthesis process of the present invention, the metal ion solution and the locene ligand can be fully contacted, and because the temperature in the fluidized bed reactor is uniform and the concentration of the reaction system is uniform, the reaction can be fully carried out, thereby improving the conversion rate of the active center during the chemical reaction, that is, improving the conversion rate of the ion reaction. During the gas purification process of the present invention, the protective gas and the adsorbent particles can be fully contacted, greatly reducing the content of impurities such as water and oxygen in the gas, making the purified gas suitable as a reaction atmosphere for the homogeneous metallocene catalyst synthesis process. In addition, the homogeneous metallocene catalyst preparation system of the present invention makes it easy to separate the prepared catalyst and makes the solvent recovery simple and efficient. Therefore, the present invention solves the problems of low ion reaction conversion rate and high water and oxygen content in the atmosphere in the prior art during the synthesis of homogeneous metallocene catalysts. The present invention improves the synthesis efficiency and yield of the homogeneous metallocene catalyst, improves the purity of the homogeneous metallocene catalyst, and reduces the cost of the catalyst.

[0046] A second aspect of the present invention provides a method for preparing a homogeneous metallocene catalyst, which is a method for preparing a homogeneous metallocene catalyst using the above-mentioned homogeneous metallocene catalyst preparation system, and the method comprises the following steps:

[0047] (1) adding a solid metallocene ligand and a solvent to the fluidized bed reactor, and then introducing a protective gas into the fluidized bed reactor, wherein the protective gas is a protective gas purified by the fluidized bed gas purifier, and the protective gas strongly disturbs the solid metallocene ligand to form a fluidized bed, and the metal ion solution is sprayed into the fluidized bed reactor in the form of droplets through the nozzle, and the metal ions react with the metallocene ligand to generate a homogeneous metallocene catalyst, and the protective gas entrains the solvent and is discharged from the gas outlet of the fluidized bed reactor;

[0048] (2) The protective gas discharged from the gas outlet of the fluidized bed reactor carries the solvent into the condenser, and the protective gas obtained after condensation is discharged from the gas outlet of the condenser, and the obtained solvent is discharged from the solvent outlet of the condenser;

[0049] (3) The protective gas discharged from the gas outlet of the condenser enters the fluidized bed gas purifier, and the adsorbent particles in the fluidized bed gas purifier are strongly disturbed to form a fluidized bed. The adsorbent particles adsorb water and oxygen in the protective gas to obtain purified protective gas, which is discharged from the gas outlet of the fluidized bed gas purifier. The discharged protective gas enters the fluidized bed reactor.

[0050] In the above preparation method, preferably, in step (1), the reaction temperature in the fluidized bed reactor is -40 to 40°C.

[0051] In the above preparation method, preferably, in step (1), the reaction pressure in the fluidized bed reactor is 0.1-2 MPa.

[0052] In the above preparation method, the temperature and pressure in the fluidized bed reactor can be detected by the temperature and pressure detection components on the top of the fluidized bed reactor.

[0053] In the above preparation method, preferably, in step (1), the fluidization velocity in the fluidized bed reactor is 0.1-5 m / s. It will be understood by those skilled in the art that the fluidization velocity refers to the superficial velocity of the fluid formed by the solid octyl ligand.

[0054] In the above preparation method, preferably, in step (1), the crystal size of the solid cyclopentadiene ligand is 10-100 μm.

[0055] In the above preparation method, preferably, in step (1), the particle size of the solid octahedron ligand is 500-5000 μm.

[0056] In the above preparation method, preferably, in step (1), the ratio of the solid cyclopentadiene ligand to the solvent is 50-500 g:1 L.

[0057] In the above preparation method, preferably, in step (1), the metal ion concentration in the metal ion solution is 0.1-100 g / L.

[0058] In some specific embodiments of the present invention, the solid metallocene ligand, the solvent, and the metal ion solution can all be conventional raw materials for preparing homogeneous metallocene catalysts in the art, and the present invention does not impose any particular limitation on the specific compounds that can be selected.

[0059] In the above preparation method, preferably, in step (2), the temperature in the condenser is -50 to 50°C.

[0060] In the above preparation method, preferably, in step (2), the pressure in the condenser is 0.1-2 MPa. The pressure in the condenser can be adjusted by a pressure relief valve at the top of the condenser and / or by adding protective gas through the gas inlet.

[0061] In the above-mentioned preparation method, preferably, in step (2), the residence time of the solvent entrained in the protective gas discharged from the gas outlet of the fluidized bed reactor in the condenser is 0.1-20 minutes. This residence time in the condenser can ensure that the solvent entrained in the protective gas is fully settled. Therefore, the pipeline in the condenser should be designed to be long enough to ensure that the solvent can be fully settled.

[0062] In the above preparation method, preferably, in step (2), the flow rate of the shielding gas carrying the solvent in the condenser is less than 1 m / min. If the flow rate is too fast, it will have an adverse effect on the sedimentation of the solvent carried in the shielding gas.

[0063] According to a specific embodiment of the present invention, the present invention adopts supercondensation to condense and recover the solvent entrained in the protective gas to ensure that all gaseous solvents are completely liquefied, and adopts folded plate condensation to increase the residence time of the protective gas, thereby improving the solvent recovery efficiency.

[0064] In the above preparation method, preferably, in step (3), the temperature in the fluidized bed gas purifier is -50 to 50°C.

[0065] In the above preparation method, preferably, in step (3), the pressure in the fluidized bed gas purifier is 0.1-2 MPa.

[0066] In the above preparation method, preferably, in step (3), the fluidization velocity in the fluidized bed gas purifier is 0.1-5 m / s. It will be understood by those skilled in the art that the fluidization velocity refers to the superficial velocity of the fluid formed by the adsorbent particles.

[0067] In the above preparation method, preferably, step (3) further comprises: after detecting the water and oxygen contents in the shielding gas at the gas outlet of the fluidized bed gas purifier by the gas impurity detection component, if the water and oxygen contents do not meet the requirements, re-entering the shielding gas into the fluidized bed gas purifier for purification. More preferably, if the water content in the shielding gas is less than 5 ppm and the oxygen content is less than 5 ppm, the requirements are met; otherwise, the requirements are not met.

[0068] According to a specific embodiment of the present invention, the present invention uses a fluidized bed gas purifier to purify the protective gas. During the purification process, the protective gas strongly disturbs the adsorbent particles (such as molecular sieves, etc.) to form a fluidized bed, thereby efficiently adsorbing water and oxygen in the protective gas, and re-purifying the protective gas that does not meet the water and oxygen content requirements, and the protective gas that meets the water and oxygen content requirements enters the fluidized bed reactor.

[0069] In the above-described preparation method, preferably, in step (3), the purified protective gas discharged from the gas outlet of the fluidized bed gas purifier is compressed by a compressor and then enters the fluidized bed reactor. More preferably, the purified protective gas is compressed by the compressor to a pressure of 0.1-2 MPa and a temperature of -50 to 50°C. The present invention uses a compressor to provide pressure for the entire reaction system.

[0070] In the above preparation method, preferably, the protective gas includes one or a combination of nitrogen, helium, neon, etc.

[0071] In the above preparation method, preferably, the prepared homogeneous metallocene catalyst (ie, metallocene complex) has a crystal size of 10-100 μm and a particle size of 500-5000 μm.

[0072] The present invention provides a homogeneous metallocene catalyst preparation system and method. This system utilizes a dual fluidized bed to synthesize the homogeneous metallocene catalyst and purify the gas. This reduces the water and oxygen content in the atmosphere during the chemical reaction between the metallocene ligand and the metal ion, increases the conversion rate of the active center during the chemical reaction, and enables efficient, green, and stable synthesis of the homogeneous metallocene catalyst. The homogeneous metallocene catalyst preparation system and method of the present invention are particularly suitable for producing homogeneous metallocene catalysts for synthesizing polyolefin elastomers.

[0073] The technical solution of the present invention has at least the following beneficial effects:

[0074] The ion reaction conversion rate of the homogeneous metallocene catalyst and the water-oxygen content of the reaction system determine the purity and synthesis efficiency of the catalyst. The present invention adopts a dual fluidized bed to complete the synthesis of the homogeneous metallocene catalyst and the purification of the gas, thereby achieving deep purification of the atmosphere and efficient combination of metal ions and metallocene ligands. Therefore, the technical solution of the present invention improves the synthesis efficiency and yield of the homogeneous metallocene catalyst, improves the purity of the homogeneous metallocene catalyst, and reduces the cost of the catalyst. The purity of the homogeneous metallocene catalyst provided by the present invention is more than 97%, and the yield is more than 85%. In addition, the technical solution of the present invention makes it easy to separate the prepared catalyst and makes the recovery of the solvent simple and efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] FIG1 is a schematic structural diagram of a homogeneous metallocene catalyst preparation system in one embodiment of the present invention.

[0076] Explanation of the accompanying figures: 1- fluidized bed reactor; 2- temperature and pressure detection assembly; 3- first material level detection assembly; 11- nozzle; 12- first gas distributor; 4- condenser; 41- baffle; 42- pressure relief valve; 43- gas supply port; 5- fluidized bed gas purifier; 51- second gas distributor; 6- gas impurity detection assembly; 7- second material level detection assembly; 8- compressor; 9- initial protective gas delivery pipeline; 10- protective gas return pipeline. DETAILED DESCRIPTION

[0077] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.

[0078] Some specific embodiments of the present invention provide a homogeneous metallocene catalyst preparation system, the structure of which is shown in FIG1 , and the system comprises at least: a homogeneous metallocene catalyst synthesis unit, a solvent condensation and collection unit, and a gas purification unit;

[0079] Among them, the homogeneous metallocene catalyst synthesis unit includes a fluidized bed reactor 1 and a temperature and pressure detection component 2; the fluidized bed reactor 1 includes a reactor shell, an air inlet, an air outlet, a metallocene ligand feed port, a metal ion solution feed port, a solvent feed port, a discharge port, and a nozzle 11; the air inlet and the discharge port are arranged at the lower part of the reactor shell; the metallocene ligand feed port, the metal ion solution feed port and the solvent feed port are arranged on the side wall of the reactor shell; the air outlet is arranged at the top of the reactor shell; the nozzle 11 is arranged on the inner wall of the reactor shell; the nozzle 11 is connected to the metal ion solution feed port; the temperature and pressure detection component 2 is arranged at the top of the reactor shell for detecting the temperature and pressure inside the reactor shell;

[0080] The solvent condensation and collection unit includes a condenser 4; the condenser 4 is provided with at least a condensation medium inlet, a condensation medium outlet, an air inlet, an air outlet, and a solvent outlet; the condensation medium inlet is provided at the lower part of the condenser 4, the condensation medium outlet is provided at the upper part of the condenser 4, the air inlet is provided at the upper part of the condenser 4, the air outlet is provided at the top of the condenser 4, and the solvent outlet is provided at the bottom of the condenser 4;

[0081] The gas purification unit includes a fluidized bed gas purifier 5; the fluidized bed gas purifier 5 includes a purifier housing, an air inlet, and an air outlet; the air inlet is arranged at the lower part of the purifier housing; the air outlet is arranged at the top of the purifier housing; the interior of the purifier housing has adsorbent particles;

[0082] The gas outlet of the fluidized bed reactor 1 is connected to the gas inlet of the condenser 4 through a pipeline;

[0083] The gas outlet of the condenser 4 is connected to the gas inlet of the fluidized bed gas purifier 5 through a pipeline;

[0084] The gas outlet of the fluidized bed gas purifier 5 is connected to the gas inlet of the fluidized bed reactor 1 through a pipeline.

[0085] In one embodiment, the homogeneous metallocene catalyst synthesis unit further comprises a first material level detection component 3 , which is disposed inside the reactor shell.

[0086] In one embodiment, the gas purification unit further comprises a second material level detection assembly 7 , which is disposed inside the purifier housing.

[0087] In one embodiment, the gas purification unit further includes a gas impurity detection component 6 , which is disposed at the gas outlet of the fluidized bed gas purifier 5 .

[0088] In one embodiment, in the fluidized bed reactor 1, there are one or more nozzles 11, all of which are disposed on the inner wall of the reactor shell. It will be appreciated by those skilled in the art that, when multiple nozzles 11 are provided, there are also multiple metal ion solution feed ports, each of which is connected to the multiple nozzles 11.

[0089] In one embodiment, a first gas distributor 12 is further provided inside the fluidized bed reactor 1. The first gas distributor 12 is located above the gas inlet of the fluidized bed reactor 1. The gas distributor used is a conventional device in the art, and the present invention does not specifically limit its specific structure.

[0090] In one embodiment, a compressor 8 is provided on the pipeline connecting the gas outlet of the fluidized bed gas purifier 5 and the gas inlet of the fluidized bed reactor 1 .

[0091] In one embodiment, the condenser 4 is a shell-and-tube condenser. Specifically, the condenser 4 includes a condenser shell, a plurality of heat exchange tubes (not shown in FIG1 ), and a plurality of baffles 41 . The heat exchange tubes and the baffles 41 are disposed within the condenser shell. The condensing medium inlet and the condensing medium outlet are connected to the heat exchange tubes. The baffles 41 are staggered along the vertical direction of the condenser shell and can be sealed and sleeved with the heat exchange tubes. The baffles 41 form a baffle group in a vertically zigzag shape. The condensing medium can be conventional in the art, such as, but not limited to, water.

[0092] In one embodiment, a pressure relief valve 42 is provided on the top of the condenser 4 .

[0093] In one embodiment, an air supply port 43 is provided on the side wall of the condenser 4 .

[0094] The air supply port 43 and the pressure relief valve 42 of the condenser 4 can control the pressure of the system, and can replenish pressure or release pressure for the system, thereby avoiding accidents caused by abnormal working conditions such as excessive system pressure and incomplete condensation.

[0095] In one embodiment, a solution concentration detector is provided at the solvent outlet of the condenser 4 to detect the concentration and composition of the liquid discharged from the solvent outlet of the condenser. The solution concentration detector used is a conventional device in the art, and the present invention does not specifically limit its specific structure.

[0096] In one embodiment, the adsorbent particles within the purifier housing are particles capable of adsorbing water and oxygen. Preferably, the adsorbent comprises a molecular sieve. Specifically, the molecular sieve comprises one or a combination of 5A molecular sieve, 3A molecular sieve, 4A molecular sieve, and 13X molecular sieve.

[0097] In one embodiment, the gas purification unit further comprises: an initial protective gas delivery pipeline 9, which is connected to the gas inlet of the fluidized bed gas purifier 5 and is used to provide initial protective gas to the system.

[0098] In one embodiment, the gas impurity detection component 6 includes a gas chromatograph and an online sampling probe thereof.

[0099] In one embodiment, the gas purification unit further includes: a protective gas return pipeline 10, one end of the protective gas return pipeline 10 is connected to the gas impurity detection component 6, and the other end is connected to the air inlet of the fluidized bed gas purifier 5, which is used to allow the protective gas whose water and oxygen content does not meet the requirements after detection by the gas impurity detection component 6 to re-enter the fluidized bed gas purifier 5 for purification.

[0100] In one embodiment, a second gas distributor 51 is further provided inside the fluidized bed gas purifier 5. The second gas distributor 51 is located above the gas inlet of the fluidized bed gas purifier 5. The gas distributor used is a conventional device in the art, and the present invention does not specifically limit its specific structure.

[0101] In one embodiment, the solvent outlet of the condenser 4 is connected to the solvent feed inlet of the fluidized bed reactor 1 through a pipeline (not shown in FIG. 1 ).

[0102] In the above embodiments, the temperature and pressure detection component 2 and the first material level detection component 3 in the homogeneous metallocene catalyst synthesis unit, and the second material level detection component 7 in the gas purification unit are all conventional devices in the field, and the present invention does not specifically limit their specific structures.

[0103] In the above embodiments, necessary valves, such as stop valves, etc., may be provided on each pipeline, and those skilled in the art may make conventional settings according to actual conditions.

[0104] In one embodiment, the system further comprises: a ligand synthesis unit for synthesizing the cyclopentadienyl ligand. The ligand synthesis unit can be a ligand synthesis device in the prior art, and the present invention does not impose any particular limitation on its structure.

[0105] In one embodiment, the system further comprises a recrystallization unit for recrystallizing and purifying the cyclopentadienyl ligand synthesized in the ligand synthesis unit. The recrystallization unit can be operated using conventional equipment and is not particularly limited in the present invention. The recrystallization unit can be connected to the cyclopentadienyl ligand feed port of the fluidized bed reactor via a pipeline.

[0106] In one embodiment, the system further includes: a raw material storage unit, comprising a storage device for raw materials for synthesizing ligands, a storage device for a metal ion solution, and a storage device for a solvent; the storage device for raw materials for synthesizing ligands is connected to the ligand synthesis unit; the storage device for the metal ion solution is connected to the metal ion solution feed port of the fluidized bed reactor; and the storage device for the solvent is connected to the solvent feed port of the fluidized bed reactor. These storage devices can all be conventional storage devices and are not specifically limited in the present invention.

[0107] In one embodiment, the system further includes a raw material refining unit connected to the raw material storage unit for refining raw materials for synthesizing the ligand, raw materials for synthesizing the metal ion solution, and solvent. The raw material refining unit can employ a raw material refining device known in the art, and the present invention does not impose any particular limitation on its structure.

[0108] In one embodiment, the above system further includes: a solvent recovery unit, which is connected to the solvent outlet of the condenser through a pipeline for recovering the solvent. The recovered solvent can be returned to the above-mentioned raw material refining unit and raw material storage unit, and then returned to the homogeneous metallocene catalyst synthesis unit to achieve the reuse of the solvent. It will be understood by those skilled in the art that the solvent recovered by the solvent recovery unit includes the solvent in the metal ion solution and the solvent entering the system from the solvent feed port of the fluidized bed reactor. In addition, it will be understood by those skilled in the art that when the system of the present invention does not include a solvent recovery unit, as described above, the solvent outlet of the condenser can be directly connected to the solvent feed port of the fluidized bed reactor through a pipeline.

[0109] In one embodiment, the system further comprises: a catalyst storage unit, which is connected to the discharge port of the fluidized bed reactor via a pipeline and is used to store the prepared homogeneous metallocene catalyst.

[0110] Other specific embodiments of the present invention provide a method for preparing a homogeneous metallocene catalyst, which is a method for preparing a homogeneous metallocene catalyst using the above-mentioned homogeneous metallocene catalyst preparation system, and the method comprises the following steps:

[0111] (1) adding a solid metallocene ligand and a solvent to a fluidized bed reactor 1, and then introducing a protective gas into the fluidized bed reactor 1, wherein the protective gas is a protective gas purified by a fluidized bed gas purifier 5, and the protective gas strongly disturbs the solid metallocene ligand to form a fluidized bed, and sprays the metal ion solution in the form of droplets onto the bed of the fluidized bed reactor 1 through a nozzle 11, and adjusts the bed temperature of the fluidized bed reactor 1 and the pressure in the fluidized bed reactor 1, wherein the bed temperature of the fluidized bed reactor 1 is adjusted by the feed temperature and the reaction heat, and the metal ions adhere to the solid metallocene ligand to react to generate a homogeneous metallocene catalyst, and the protective gas entrains the solvent and is discharged from the gas outlet of the fluidized bed reactor 1;

[0112] (2) The protective gas discharged from the gas outlet of the fluidized bed reactor 1 carries the solvent into the condenser 4, and the protective gas obtained after condensation is discharged from the gas outlet of the condenser 4, and the obtained solvent is discharged from the solvent outlet of the condenser 4;

[0113] (3) At the initial stage of preparation, the protective gas is introduced into the fluidized bed gas purifier 5 through the initial protective gas delivery pipeline 9. After the amount of the protective gas meets the reaction requirements in the fluidized bed reactor 1, the protective gas is no longer provided through the initial protective gas delivery pipeline 9, and the protective gas discharged from the gas outlet of the condenser 4 enters the fluidized bed gas purifier 5. The protective gas strongly disturbs the adsorbent particles in the fluidized bed gas purifier 5 to form a fluidized bed. The adsorbent particles adsorb water and oxygen in the protective gas to obtain purified protective gas and discharge it from the gas outlet of the fluidized bed gas purifier 5. The water and oxygen contents in the protective gas at the gas outlet of the fluidized bed gas purifier 5 are detected by the gas impurity detection component 6. If the water and oxygen contents do not meet the requirements, the protective gas is re-entered into the fluidized bed gas purifier 5 for purification. If the water content in the protective gas is less than 5 ppm and the oxygen content is less than 5 ppm, the requirements are met. Otherwise, the requirements are not met. The protective gas that meets the water and oxygen content requirements is compressed by the compressor 8 and enters the fluidized bed reactor 1.

[0114] In one embodiment, in step (1), the reaction temperature in the fluidized bed reactor 1 is -40 to 40°C, specifically 0°C. The reaction pressure in the fluidized bed reactor 1 is 0.1-2 MPa, specifically 0.5 MPa. The temperature and pressure in the fluidized bed reactor 1 can be detected by the temperature and pressure detection component 2 at the top of the fluidized bed reactor 1. The fluidization velocity in the fluidized bed reactor 1 is 0.1-5 m / s, specifically 2 m / s. It will be understood by those skilled in the art that the fluidization velocity refers to the superficial velocity of the fluid formed by the solid cyclopentadiene ligand.

[0115] In this embodiment, in step (1), the crystal size of the solid octahedral ligand is 10-100 μm, specifically about 50 μm. The particle size of the solid octahedral ligand is 500-5000 μm, specifically 2000-3000 μm. The ratio of the solid octahedral ligand to the solvent is 50-500 g:1 L, specifically 100 g:1 L. The metal ion concentration in the metal ion solution is 0.1-100 g / L, specifically 50 g / L.

[0116] In this embodiment, the solid metallocene ligand, solvent, and metal ion solution can all be conventional raw materials for preparing homogeneous metallocene catalysts in the art, and the present invention does not impose any particular limitation on the specific compounds that can be selected.

[0117] In this embodiment, in step (2), the temperature in the condenser 4 is -50 to 50°C, specifically 0°C. The pressure in the condenser 4 is 0.1-2 MPa, specifically 1 MPa. The pressure in the condenser can be adjusted by the pressure relief valve 42 at the top of the condenser 4 and / or by supplementing the protective gas through the gas supply port 43. The residence time of the protective gas entrained solvent discharged from the gas outlet of the fluidized bed reactor 1 in the condenser 4 is 0.1-20 min, specifically 10 min. The flow rate of the protective gas entrained solvent in the condenser 4 is less than 1 m / min.

[0118] In this embodiment, the solvent entrained in the shielding gas is condensed and recovered by supercondensation to ensure that all gaseous solvents are completely liquefied. The folded plate condensation method is used to increase the residence time of the shielding gas and improve the solvent recovery efficiency.

[0119] In this embodiment, in step (3), the temperature within the fluidized bed gas purifier 5 is between -50°C and 50°C, specifically 0°C. The pressure within the fluidized bed gas purifier 5 is between 0.1 MPa and 2 MPa, specifically 0.5 MPa. The fluidization velocity within the fluidized bed gas purifier 5 is between 0.1 m / s and 5 m / s, specifically 2 m / s. It will be understood by those skilled in the art that the fluidization velocity refers to the superficial velocity of the fluid formed by the adsorbent particles.

[0120] According to a specific embodiment of the present invention, the present invention uses a fluidized bed gas purifier to purify the protective gas. During the purification process, the protective gas strongly disturbs the adsorbent particles (such as molecular sieves, etc.) to form a fluidized bed, thereby efficiently adsorbing water and oxygen in the protective gas, and re-purifying the protective gas that does not meet the water and oxygen content requirements, and the protective gas that meets the water and oxygen content requirements enters the fluidized bed reactor.

[0121] In this embodiment, in step (3), the protective gas is compressed by the compressor 8 to a pressure of 0.1-2 MPa, specifically 0.5 MPa, and a temperature of -50 to 50° C., specifically 0° C. In this embodiment, the compressor 8 is used to provide the pressure of the entire reaction system.

[0122] In this embodiment, the protective gas is nitrogen.

[0123] In this embodiment, the prepared homogeneous metallocene catalyst has a crystal size of about 50 μm and a particle size of 2000-3000 μm.

[0124] After testing, the purity of the homogeneous metallocene catalyst provided in this embodiment is above 97%, and the yield is above 85%.

Claims

1. A homogeneous metallocene catalyst preparation system, comprising at least: Homogeneous metallocene catalyst synthesis unit, solvent condensation and collection unit, gas purification unit; Wherein, the homogeneous metallocene catalyst synthesis unit comprises a fluidized bed reactor and a temperature and pressure detection component; the fluidized bed reactor comprises a reactor shell, an air inlet, an air outlet, a metallocene ligand feed port, a metal ion solution feed port, a solvent feed port, a discharge port, and a nozzle; the air inlet and the discharge port are arranged at the lower part of the reactor shell; the metallocene ligand feed port, the metal ion solution feed port and the solvent feed port are arranged on the side wall of the reactor shell; the air outlet is arranged at the top of the reactor shell; the nozzle is arranged on the inner wall of the reactor shell; the nozzle is connected to the metal ion solution feed port; the temperature and pressure detection component is arranged at the top of the reactor shell, and is used to detect the temperature and pressure inside the reactor shell; The solvent condensation and collection unit comprises a condenser; the condenser is at least provided with a condensation medium inlet, a condensation medium outlet, an air inlet, an air outlet, and a solvent outlet; the condensation medium inlet is arranged at the lower part of the condenser, the condensation medium outlet is arranged at the upper part of the condenser, the air inlet is arranged at the upper part of the condenser, the air outlet is arranged at the top of the condenser, and the solvent outlet is arranged at the bottom of the condenser; The gas purification unit comprises a fluidized bed gas purifier; the fluidized bed gas purifier comprises a purifier housing, an air inlet, and an air outlet; the air inlet is arranged at the lower part of the purifier housing; the air outlet is arranged at the top of the purifier housing; the interior of the purifier housing has adsorbent particles; The gas outlet of the fluidized bed reactor is connected to the gas inlet of the condenser through a pipeline; The gas outlet of the condenser is connected to the gas inlet of the fluidized bed gas purifier through a pipeline; The gas outlet of the fluidized bed gas purifier is connected to the gas inlet of the fluidized bed reactor through a pipeline.

2. The homogeneous metallocene catalyst preparation system according to claim 1, wherein: The homogeneous metallocene catalyst synthesis unit and the gas purification unit further include: a material level detection component, which is respectively arranged inside the reactor shell and inside the purifier shell.

3. The homogeneous metallocene catalyst preparation system according to claim 1, wherein: The gas purification unit further comprises a gas impurity detection component, which is arranged at the gas outlet of the fluidized bed gas purifier.

4. The homogeneous metallocene catalyst preparation system according to claim 1, wherein: In the fluidized bed reactor, the number of the nozzles is one or more, and all are arranged on the inner wall of the reactor shell.

5. The homogeneous metallocene catalyst preparation system according to claim 1, wherein: A compressor is arranged on the pipeline connecting the gas outlet of the fluidized bed gas purifier and the gas inlet of the fluidized bed reactor.

6. The homogeneous metallocene catalyst preparation system according to claim 1, wherein: The condenser comprises a shell and tube condenser.

7. The homogeneous metallocene catalyst preparation system according to claim 6, wherein: The condenser comprises a condenser shell, a plurality of heat exchange tubes and a plurality of baffles, wherein the plurality of heat exchange tubes and the plurality of baffles are arranged inside the condenser shell, the condensing medium inlet and the condensing medium outlet are connected to the plurality of heat exchange tubes, and the plurality of baffles are staggeredly arranged along the vertical direction of the condenser shell; A pressure relief valve is provided on the top of the condenser; The side wall of the condenser is provided with an air supply port; A solution concentration detector is arranged at the solvent outlet of the condenser.

8. The homogeneous metallocene catalyst preparation system according to claim 7, wherein: The plurality of baffles in the condenser form a baffle group which is in a zigzag shape in the vertical direction.

9. The homogeneous metallocene catalyst preparation system according to claim 1, wherein: The adsorbent includes a molecular sieve.

10. The homogeneous metallocene catalyst preparation system according to claim 1, wherein: The gas purification unit further comprises: an initial protective gas delivery pipeline, which is connected to the gas inlet of the fluidized bed gas purifier and is used to provide initial protective gas to the system.

11. The homogeneous metallocene catalyst preparation system according to claim 3, wherein: The gas purification unit further includes: a protective gas return pipeline, one end of which is connected to the gas impurity detection component, and the other end is connected to the air inlet of the fluidized bed gas purifier, so as to allow the protective gas whose water and oxygen content does not meet the requirements after detection by the gas impurity detection component to re-enter the fluidized bed gas purifier for purification.

12. A method for preparing a homogeneous metallocene catalyst, the method comprising: using the homogeneous metallocene catalyst preparation system according to any one of claims 1 to 11 to prepare a homogeneous metallocene catalyst. The method comprises the following steps: (1) adding a solid metallocene ligand and a solvent to the fluidized bed reactor, and then introducing a protective gas into the fluidized bed reactor, wherein the protective gas is a protective gas purified by the fluidized bed gas purifier, and the solid metallocene ligand is strongly disturbed by the protective gas to form a fluidized bed, and a metal ion solution is sprayed into the fluidized bed reactor in the form of droplets through the nozzle, and the metal ions react with the metallocene ligand to generate a homogeneous metallocene catalyst, and the protective gas entrains the solvent and is discharged from the gas outlet of the fluidized bed reactor; (2) the protective gas discharged from the gas outlet of the fluidized bed reactor carries the solvent into the condenser, the protective gas obtained after condensation is discharged from the gas outlet of the condenser, and the obtained solvent is discharged from the solvent outlet of the condenser; (3) The protective gas discharged from the gas outlet of the condenser enters the fluidized bed gas purifier to The adsorbent particles in the fluidized bed gas purifier are strongly disturbed to form a fluidized bed. The adsorbent particles adsorb water and oxygen in the protective gas to obtain purified protective gas, which is discharged from the gas outlet of the fluidized bed gas purifier. The discharged protective gas enters the fluidized bed reactor.

13. The method for preparing a homogeneous metallocene catalyst according to claim 12, wherein: In step (1), the reaction temperature in the fluidized bed reactor is -40 to 40°C; In step (1), the reaction pressure in the fluidized bed reactor is 0.1-2 MPa; In step (1), the fluidization velocity in the fluidized bed reactor is 0.1-5 m / s.

14. The method for preparing a homogeneous metallocene catalyst according to claim 12, wherein: In step (1), the crystal size of the solid cyclopentadienyl ligand is 10-100 μm; In step (1), the particle size of the solid cyclopentadienyl ligand is 500-5000 μm; In step (1), the ratio of the solid cyclopentadienyl ligand to the solvent is 50-500 g:1 L.

15. The method for preparing a homogeneous metallocene catalyst according to claim 12, wherein: In step (1), the metal ion concentration in the metal ion solution is 0.1-100 g / L.

16. The method for preparing a homogeneous metallocene catalyst according to claim 12, wherein: In step (2), the temperature in the condenser is -50 to 50°C; In step (2), the pressure in the condenser is 0.1-2 MPa; In step (2), the residence time of the protective gas entrained with the solvent discharged from the gas outlet of the fluidized bed reactor in the condenser is 0.1-20 min.

17. The method for preparing a homogeneous metallocene catalyst according to claim 12, wherein: In step (3), the temperature in the fluidized bed gas purifier is -50 to 50°C; In step (3), the pressure in the fluidized bed gas purifier is 0.1-2 MPa; In step (3), the fluidization velocity in the fluidized bed gas purifier is 0.1-5 m / s.

18. The method for preparing a homogeneous metallocene catalyst according to claim 12, wherein: Step (3) further includes: after detecting the water and oxygen contents in the protective gas at the outlet of the fluidized bed gas purifier by the gas impurity detection component, if the water and oxygen contents do not meet the requirements, the protective gas is re-entered into the fluidized bed gas purifier for purification; wherein if the water content in the protective gas is less than 5ppm and the oxygen content is less than 5ppm, it meets the requirements, otherwise it does not meet the requirements.

19. The method for preparing a homogeneous metallocene catalyst according to claim 12, wherein: In step (3), the purified protective gas discharged from the gas outlet of the fluidized bed gas purifier is compressed by a compressor and then enters the fluidized bed reactor; the pressure of the purified protective gas after compression by the compressor is 0.1-2MPa and the temperature is -50 to 50°C.

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