Catalyst for trans-oriented polymerization of dialkene as well as preparation method and application of catalyst

Abstract

The invention provides a catalyst for trans-oriented polymerization of dialkene as well as a preparation method and application of the catalyst. The catalyst comprises a transition metal compound, magnesium chloride MgCl2, an optional alkyl aluminum compound, an optional electron donor and other organic compounds, and based on the total mass of the catalyst, the content of the transition metal element is 0.1-8.0 wt%, the content of the MgCl2 is 15-30 wt%, the content of the aluminum element is 0-10 wt%, the content of the electron donor is 0-20 wt%, and the content of the other organic compounds is 0-10 wt%. The invention also provides a preparation method of the catalyst and application of the catalyst in diene polymerization. Compared with a traditional catalyst with anhydrous magnesium chloride as a carrier, the catalyst has the advantages that the polymerization catalysis efficiency of the catalyst for dialkene is greatly improved and reaches 50-500Kg of polymer / gram of transition metal / hour, and the content of trans-1, 4-structure of a dialkene monomer unit in a homopolymer or a copolymer is 95 mol% or above.

Description

Technical Field

[0001] The present invention belongs to the field of catalysts, and particularly relates to a catalyst for diolefin polymerization. More specifically, it is a catalyst for trans - oriented polymerization of diolefins, its preparation method and uses. The catalyst can improve the catalytic efficiency of diolefin polymerization and the content of trans - structure in the polymer. Background Art

[0002] Anhydrous magnesium chloride (α - MgCl2) has a cubic close - packed layered structure, with the characteristics of high crystallinity, low specific surface area and no reactive groups with substances such as TiCl4. Therefore, if it is to be used as a support for supported Ziegler - Natta catalysts, it must be activated, that is, the crystal structure of α - MgCl2 is destroyed, the grain size is reduced, and highly disordered δ - MgCl2 is formed. There are mainly two methods for activating the MgCl2 support: physical grinding method and chemical method.

[0003] Most of the supports for titanium - based supported Ziegler - Natta catalysts used in diolefin polymerization adopt the physically (grinding) activated method with simple process, that is, the support (usually anhydrous MgCl2) and the active substance (usually TiCl4) are added to a planetary ball mill for grinding. While achieving the activation of the support, the active substance can be complexed onto the support. The activity of the catalyst obtained by this method is relatively low, and the morphology of the catalyst particles is uncontrollable. For example, previously reported: CN 105623001A (activity greater than 500 g polymer / gTi / h, trans - content greater than 97%), CN 108690156A (activity of 523.6 g polymer / gTi / h, trans - content greater than 98%), CN 113773426A (highest activity of 3872 g polymer / gTi / h, highest trans - content of 97.8%).

[0004] Therefore, in order to better meet the requirements of industrialization and reduce production costs, it is necessary to prepare a supported Ziegler - Natta catalyst with high efficiency and high orientation.

[0005] Compared with the catalyst obtained by activating the support through physical grinding method, the catalyst particles with good particle morphology and high specific surface area can be prepared by activating the support through chemical activation method, making the catalyst have higher polymerization activity and has been widely used in the industrial production of α-olefins such as ethylene and propylene. However, there are few reports on the supported Ziegler-Natta catalyst for diolefin polymerization prepared by chemical activation method. CN105504113A reported the polymerization of isoprene catalyzed by a double-supported Ziegler-Natta catalyst prepared by adding SiO2 during the chemical activation process, with a polymerization activity of 9.2 g polymer / gCat / h and a trans content of 98.2%; CN 117467039A reported the preparation of an active MgCl2 support using Mg powder as a raw material, loading TiCl4 and catalyzing the polymerization of isoprene, with a polymerization activity reaching 14740.35 g polymer / gTi, but the trans content is relatively low (93.2 mol%). Summary of the Invention

[0006] Based on the problems existing in the existing catalysts for diolefin polymerization, such as low catalytic efficiency or low trans structure content, the present invention discloses a special catalyst for preparing a magnesium chloride alcoholate support precursor by chemically activating magnesium chloride and using this to prepare a catalyst, so as to achieve higher catalytic efficiency for diolefin polymerization and the trans structure content of the polymer.

[0007] One of the objectives of the present invention is to provide a special catalyst for improving the catalytic efficiency of diolefin polymerization and the trans structure content. Through the design of the main catalyst support and the construction of the catalyst system, its catalytic activity for diolefin polymerization reaches 50 - 500 Kg polymer / gram of transition metal / hour, the trans structure content of diolefin polymerization reaches more than 95 mol%, even up to 99 mol%, and the weight average molecular weight is 0.05 - 200×10 4 .

[0008] Another objective of the present invention is to provide a preparation method of this catalyst.

[0009] Another objective of the present invention is to provide the use of the said catalyst for the polymerization of diolefins, which can prepare polyolefins with a high trans structure content.

[0010] In order to achieve the above objectives and enable the catalyst to efficiently obtain polydiolefins with a high trans structure content during the polymerization of diolefins. The novelty of the present invention lies in that during the preparation of the main catalyst, a new process is adopted to prepare magnesium chloride alcoholate support precursors with different structures and alcohol contents and use this to prepare catalysts with different structures and components; at the same time, the spatial structure of the compounds of transition metal titanium and / or vanadium loaded on the support is controlled, so that when it catalyzes the polymerization of diolefins, the spatial insertion position of the monomer is restricted, and the trans structure content of the polydiolefin is increased.

[0011] According to one aspect of the present invention, there is provided a catalyst for the trans - orientation polymerization of diolefins, wherein the catalyst comprises a transition metal compound, magnesium chloride MgCl₂, an optional alkyl aluminum compound, an optional electron donor, and other organic compounds. Based on the total mass of the catalyst, the content of the transition metal element is 0.1 - 8.0 wt%, the content of MgCl₂ is 15 - 30 wt%, the content of aluminum element is 0 - 10 wt%, the content of the electron donor is 0 - 20 wt%, and the content of other organic compounds is 0 - 10 wt%.

[0012] In some embodiments, the catalyst is prepared by a chemical reaction and a complexation reaction of a transition metal compound, magnesium chloride MgCl₂, an optional alkyl aluminum, an optional electron donor, and other organic compounds in a solvent and a dispersion medium.

[0013] In some embodiments, the transition metal compound is one or more selected from compounds of titanium and vanadium, specifically one or more (such as two) selected from TiCl₄, TiBr₄, TiI₄, VCl₃, VBr₃, VOCl₃, VOBr₃, VCl₄, VBr₄, V₂O₅; the alkyl aluminum compound is an alkyl aluminum complexed on the surface of the catalyst, and the alkyl aluminum is selected from one or more (such as two) of triethyl aluminum, triisobutyl aluminum, trihexyl aluminum, trioctyl aluminum, diethyl aluminum monochloride, diisobutyl aluminum monochloride, dihexyl aluminum monochloride, dioctyl aluminum monochloride; the other organic compounds are selected from one or more (such as two) of n - hexane, cyclohexane, n - heptane, cycloheptane, n - octane, isooctane, toluene, xylene, low - molecular - weight trans - 1,4 - polyisoprene, low - molecular - weight trans - 1,4 - polybutadiene, low - molecular - weight trans - 1,4 - butadiene - isoprene copolymer, low - molecular - weight trans - 1,4 - piperylene, low - molecular - weight trans - 1,4 - butadiene - piperylene copolymer, wherein the molecular weight of the low - molecular - weight polymer is less than 1000; the electron donor is one or more (such as two) selected from ester compounds, ether compounds, and siloxane compounds.

[0014] In some embodiments, the transition metals include V and Ti, and the molar ratio of V to Ti is 0 - 1:1.

[0015] In some embodiments, the catalyst is a solid particle, and its average BET specific surface area is 30 - 70 m 2 / g (such as 35, 40, 45, 50, 55, 60, 65 m 2 / g), with an average pore diameter of 40 to 1000 nm (such as 100, 200, 300, 400, 600, 800, 900 nm), and an average porosity of 30 - 80% (such as 35%, 45%, 55%, 65%, 75%).

[0016] According to the present invention, in the catalyst, the transition metal, magnesium chloride MgCl2, alkyl aluminum, electron donor, and other organic compounds may exist in the form of a complex.

[0017] In some embodiments, the catalytic activity of the catalyst for diolefin polymerization reaches 50 to 500 Kg polymer / gram of transition metal / hour.

[0018] According to another aspect of the present invention, there is provided a method for preparing the catalyst, comprising the following steps:

[0019] S1, preparation of the carrier precursor, including:

[0020] S1-1, preparation of the metal chloride solution

[0021] Add anhydrous MgCl2 and a dispersion medium to an anhydrous and oxygen-free reactor, stir and disperse, then heat up to 40 - 100 °C, add alcohol, heat up to 60 - 150 °C again, and stir constantly until MgCl2 is completely dissolved;

[0022] S1-2, preparation of the carrier particles

[0023] Subsequently, transfer the system to a low-temperature medium at 0 °C to -80 °C (such as -30 °C, -50 °C) for cooling, stir, add an inert solvent at the same temperature as the system temperature to the reactor, continue stirring until a large amount of solid particles precipitate, then filter and wash with the inert solvent to obtain solid particles;

[0024] S1-3, formation of the carrier precursor

[0025] Gradiently heat the solid particles from 30 °C to 40 - 250 °C (such as 80 °C, 100 °C, 120 °C, 150 °C, 200 °C) at a heating rate of 1 - 50 °C / minute (such as 10 °C, 20 °C, 30 °C), with each gradient interval being 5 - 50 °C (such as 10 °C, 30 °C, 45 °C), and keep the temperature constant at each gradient for 30 - 600 min. During the heating process, maintain the vacuum degree at -0.01 to -0.5 Mpa (such as -0.02 Mpa, -0.05 Mpa, -0.1 Mpa). At the final temperature of 40 - 250 °C, keep the temperature and pressure constant at -0.01 to -0.5 Mpa for another 30 - 600 min to obtain the carrier precursor;

[0026] S2, preparation of the solid catalyst particles, including:

[0027] S2-1. Under anhydrous and anaerobic conditions at room temperature, add the carrier precursor prepared in S1 into an inert solvent, and stir at room temperature for dispersion to obtain a suspension;

[0028] S2-2. Cool the suspension obtained in S2-1 to -80 to 0 °C (such as -50 °C, -30 °C or -20 °C), and dropwise add a transition metal compound to the suspension at this temperature. The mass ratio of the transition metal compound to the carrier precursor is 2:1 to 100:1; then heat up to 110 to 180 °C (such as 110 °C, 130 °C) and react at a constant temperature, and filter; if necessary, add an electron donor at 55 to 120 °C (such as 70 °C) during the heating process and react at a constant temperature, and then heat up to 110 to 180 °C and react at a constant temperature, and filter;

[0029] S2-3. Add the same amount of transition metal compound as in S2-2 into the reactor, heat the reactor to 110 to 180 °C (such as 110 °C, 130 °C), after reaction, filter;

[0030] S2-4. Add an inert solvent into the reactor, stir at -20 to 80 °C, filter and wash, and vacuum dry the obtained powder solid to obtain solid catalyst particles;

[0031] S3. Pretreatment of solid catalyst particles:

[0032] At room temperature, add the solid catalyst particles obtained in step S2 into an inert solvent, stir and disperse at room temperature to obtain a suspension, filter and vacuum dry to obtain pretreated catalyst particles; if necessary, cool the above suspension to -10 to 20 °C (such as 0 °C, 10 °C), add an alkylaluminum, optionally introduce a single or mixed diolefin monomer, react at a constant temperature of -10 to 20 °C (such as 0 °C, 10 °C), filter and vacuum dry to obtain the pretreated catalyst.

[0033] In some embodiments, in the preparation S1 of the carrier precursor, in S1-1, stir and disperse at a speed of 10 to 1000 revolutions per minute (such as 300 to 800 revolutions per minute, especially 400, 500, 600 revolutions per minute) for 5 - 100 min, and heat up at a rate of 1 to 50 °C per minute.

[0034] In some embodiments, in S1-1 of step S1, the mass ratio of anhydrous MgCl2 to the dispersion medium is 1:1 to 1:100 (such as 1:10, 1:20, 1:50, 1:80), and the dispersion medium is one or more (such as two) selected from n-nonane, n-decane, undecane, dodecane, white oil, paraffin oil, kerosene.

[0035] In some embodiments, in S1-1 of step S1, the alcohol used is one or more (e.g., two) of saturated or unsaturated alcohols having 1 to 20 carbon atoms, such as C2, C4, C6, C8 alkyl alcohols, and the mass ratio of anhydrous MgCl2 to the alcohol is 1:1 to 1:100 (e.g., 1:5).

[0036] In some embodiments, in S1-1 of step S1, anhydrous MgCl2 is added alone to the anhydrous and oxygen-free reactor, or anhydrous MgCl2 and a part of transition metal (e.g., vanadium) compounds are added to the reactor together.

[0037] In some embodiments, in S1-2 of the preparation of the carrier precursor S1, stirring is carried out at a speed of 50 to 10,000 revolutions per minute (e.g., 2000, 4000, 6000, 8000 revolutions per minute), and the mass ratio of anhydrous MgCl2 to the inert solvent is 1:1 to 1:100 (e.g., 1:10, 1:25, 1:50).

[0038] In some embodiments, in S1-2 of step S1, the inert solvent used is one or more (e.g., two) selected from n-hexane, cyclohexane, n-heptane, cycloheptane, n-octane, isooctane, toluene, xylene.

[0039] According to the present invention, in S1-3 of step S1, the obtained carrier precursor is a magnesium chloride alcoholate, and its structure is MgCl2·nROH, where R is a C1-C20 alkyl group (e.g., C2, C4, C6, C8 alkyl groups), and n is 0.01 to 6. In particular, the average specific surface area of the magnesium chloride alcoholate is 20 to 70 m 2 / g, the average pore diameter is 40 to 1000 nm, and the average porosity is 30-80%.

[0040] In some embodiments, the preparation of the carrier precursor S1 includes:

[0041] S1-1, adding anhydrous MgCl2 or a combination thereof with vanadium compounds and a dispersion medium to the anhydrous and oxygen-free reactor, stirring and dispersing at a speed of 10 to 1000 revolutions per minute (e.g., 300 to 800 revolutions per minute, especially 400, 500, 600 revolutions per minute) for 5-100 min, heating to 40 to 100 °C at a heating rate of 1 to 50 °C / min, adding alcohol, and then heating to 60 to 150 °C again at a heating rate of 1 to 50 °C / min, and stirring at a constant temperature for 0.5 to 5 h until MgCl2 is completely dissolved;

[0042] S1-2. Subsequently, transfer the system to a low-temperature medium at 0°C to -80°C (such as -30°C, -50°C) for cooling. Stir at a speed of 50 to 10,000 revolutions per minute (such as 2,000, 4,000, 6,000, 8,000 revolutions per minute) for 0.5 to 30 minutes, then add an inert solvent at the same temperature as the system temperature (0°C to -80°C) to the reactor. The mass ratio of anhydrous MgCl2 to the inert solvent is 1:1 to 1:100 (such as 1:10, 1:25, 1:50). Continue stirring until a large amount of solid particles precipitate, then filter to obtain solid particles. Wash the solid particles with an excessive amount of inert solvent 1 to 3 times;

[0043] S1-3. Then, heat the solid particles from 30°C at a heating rate of 1 to 50°C per minute (such as 10°C, 20°C, 30°C) in gradients (each gradient interval is 5 to 50°C) to 40 to 250°C (such as 100°C, 120°C, 150°C, 200°C) and keep them at a constant temperature for 30 to 600 minutes at each gradient. During the heating process, maintain the vacuum degree at -0.01 to -0.5 Mpa (such as -0.02 Mpa, -0.05 Mpa, -0.1 Mpa). At 40 to 250°C and under a pressure of -0.01 to -0.5 Mpa, keep the temperature and pressure constant for another 30 to 600 minutes to obtain the carrier precursor.

[0044] In some embodiments, in the preparation of solid catalyst particles S2, in S2-1, the mass ratio of the carrier precursor to the inert solvent is 1:1 to 1:100 (such as 1:20, 1:40, 1:60).

[0045] In some embodiments, in S2-2 of step S2, the dropping rate of the transition metal is 1 to 50 ml per minute, and the mass ratio of the transition metal compound to the magnesium chloride alcoholate carrier precursor is 10:1 to 50:1 (such as 20:1, 30:1, 40:1).

[0046] In some embodiments, in S2-2 of step S2, the electron donor is one or more selected from ester compounds, ether compounds, and siloxane compounds. An exemplary embodiment is ethyl benzoate.

[0047] In some embodiments, in the preparation of solid catalyst particles S2, in S2-2 and S2-3, heat at a heating rate of 0.1 to 50°C per minute (such as 2°C per minute, 5°C per minute, 10°C per minute) respectively.

[0048] In some embodiments, in the preparation S2 of the solid catalyst particles, in S2-4, the mass ratio of the carrier precursor to the inert solvent is 1:1 to 1:100 (e.g., 1:20, 1:40, 1:60), and / or, the obtained powder solid is vacuum dried at 40 to 80 °C (e.g., 50 °C, 80 °C) for 0.1 to 5 h.

[0049] In some embodiments, in the preparation S2 of the solid catalyst particles, it includes:

[0050] S2-1, adding the above-prepared carrier precursor to the inert solvent under anhydrous and anaerobic conditions at room temperature, where the mass ratio of the carrier precursor to the inert solvent is 1:1 to 1:100 (e.g., 1:20, 1:40, 1:60), and dispersing the carrier precursor suspension at a stirring speed of 50 to 10,000 revolutions per minute at room temperature for 5 to 30 min;

[0051] S2-2, cooling the suspension obtained in S2-1 to -80 to 0 °C (e.g., -50 °C, -30 °C or -20 °C), dropping a transition metal compound into the suspension at this temperature, with a dropping rate of 1 to 50 ml / minute. After the dropping is completed, the reactor is heated at a heating rate of 0.1 to 50 °C / minute (e.g., 2 °C / minute, 5 °C / minute, 10 °C / minute) to 110 to 180 °C (e.g., 110 °C, 130 °C) and kept at a constant temperature for 0.01 to 10 hours, then filtered; if necessary, an electron donor can be added at 55 to 120 °C (e.g., 70 °C) during the heating process and kept at a constant temperature for 5 to 60 min, and then heated at a heating rate of 0.1 to 50 °C / minute to 110 to 180 °C (e.g., 110 °C, 130 °C) and kept at a constant temperature for 0.01 to 10 hours, then filtered;

[0052] S2-3, adding the same amount of transition metal compound as in S2-2 to the reactor, heating the reactor at a heating rate of 0.1 to 50 °C / minute (e.g., 2 °C / minute, 5 °C / minute, 10 °C / minute) to 110 to 180 °C (e.g., 110 °C, 130 °C), reacting for 0.01 to 10 hours, then filtering;

[0053] S2-4, adding an inert solvent to the reactor, the mass ratio of the carrier precursor to the inert solvent is 1:1 to 1:100 (e.g., 1:20, 1:40, 1:60), stirring at a speed of 50 to 10,000 revolutions per minute (e.g., 500 revolutions per minute, 1000 revolutions per minute, 2000 revolutions per minute) at -20 to 80 °C (e.g., 50 °C) for 5 to 60 min, filtering and washing, repeating 5 times, and vacuum drying the obtained powder solid at 40 to 80 °C (e.g., 50 °C, 80 °C) for 0.1 to 5 h to obtain solid catalyst particles with MgCl2 as the carrier.

[0054] In some embodiments, in the pretreatment S3 of the solid catalyst particles, the molar ratio of aluminum element to transition metal element is 0.1 to 10:1 (for example, 2:1, 4:1, 6:1).

[0055] In some embodiments, in the pretreatment S3 of the solid catalyst particles, the molar ratio of monomer to transition metal element is 0.1 to 100:1 (for example, 5:1, 20:1). If the monomer is a mixture of two monomers, the molar ratio of the monomers in the monomer mixture is 0.1:1 to 10:1 (for example, 0.1:1, 1:1).

[0056] In some embodiments, in the pretreatment S3 of the solid catalyst particles, the diolefin monomer is butadiene or isoprene or piperylene or a butadiene-isoprene mixture or a butadiene-piperylene mixture. In particular, the molar ratio of the monomers in the monomer mixture is 0.1:1 to 10:1 (for example, 0.1:1, 1:1).

[0057] In some embodiments, in the pretreatment S3 of the solid catalyst particles, the pretreated catalyst particles comprise a transition metal compound, magnesium chloride MgCl2, an alkylaluminum compound, an electron donor, and other organic compounds.

[0058] In some embodiments, in step S3, the alkylaluminum is selected from one or more of triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, diisobutylaluminum chloride, dihexylaluminum chloride, and dioctylaluminum chloride.

[0059] In some embodiments, in the pretreatment S3 of the solid catalyst particles, it includes:

[0060] At room temperature, the solid catalyst particles obtained in step S2 are added to an inert solvent, where the mass ratio of the solid catalyst particles to the inert solvent is 1:1 to 1:100 (for example, 1:1, 1:5). At room temperature, the solid particle suspension is dispersed at a stirring speed of 50 to 10,000 revolutions per minute (for example, 500 revolutions per minute) for 5 to 30 minutes, filtered and vacuum dried at 40 to 80 °C (for example, 50 °C) for 0.1 to 5 hours to obtain pretreated catalyst particles; if necessary, the above suspension is cooled to -10 to 20 °C (for example, 0 °C, 10 °C), and an alkylaluminum is added, where the molar ratio of aluminum element to transition metal element is 0.1 to 10:1 (for example, 2:1, 4:1, 6:1), and the reaction is carried out at a constant temperature for 0.1 - 30 minutes. Optionally, butadiene or isoprene or pentadiene or a butadiene-isoprene mixture or a butadiene-pentadiene mixture is introduced, where the molar ratio of the monomer to the transition metal element is 0.1 to 100:1 (for example, 5:1, 20:1), and the reaction is carried out at a constant temperature of -10 to 20 °C (for example, 0 °C, 10 °C) for 0.1 - 30 minutes, filtered and vacuum dried at 40 to 80 °C (for example, 70 °C, 80 °C) for 0.1 to 5 hours to obtain pretreated catalyst particles; where the pretreated catalyst particles contain a transition metal compound, magnesium chloride MgCl2, an alkylaluminum compound, an electron donor, and other organic compounds.

[0061] In some embodiments, according to the present invention, the transition metal compound may be one or more selected from compounds of titanium and vanadium, specifically, one or more selected from TiCl4, TiBr4, TiI4, VCl3, VBr3, VOCl3, VOBr3, VCl4, VBr4, V2O5.

[0062] According to the present invention, in some embodiments, in step S3, pretreated catalyst particles are obtained, and the content of transition metal titanium and / or vanadium element in the pretreated catalyst particles is 0.1 to 8.0 wt%, the content of magnesium element is 15 to 30 wt%, the content of aluminum element is 0 to 10 wt%, the content of the electron donor in the solid particles is 0 to 20 wt%, and the content of other organic compounds is 0 to 10 wt%.

[0063] According to another aspect of the present invention, there is provided a catalyst prepared by the above method. In particular, the catalyst has the characteristics of the above catalyst.

[0064] According to another aspect of the present invention, there is provided the use of the catalyst for the polymerization of dienes to prepare polyolefins with a high content of trans structure.

[0065] According to another aspect of the present invention, there is provided a method for the polymerization of dienes, comprising the following steps:

[0066] Quantitatively add a monomer, an alkylaluminum, the catalyst or the catalyst prepared by the method, and a molecular weight regulator into a reactor that has been pretreated under anhydrous and anaerobic conditions in sequence. The molar ratio of the transition metal element in the catalyst to the monomer is 0.001 - 100×10 -5 :1, the molar ratio of the alkylaluminum to the transition metal element in the catalyst is 5 - 800:1, the molar ratio of the molecular weight regulator to the monomer is 1:10 - 10000, and react at 10 - 70 °C for 1 h; then add a terminator such as water or alcohol into the reactor to terminate the polymerization, and place the polymer in a vacuum drying oven to dry to a constant weight to obtain a diene homopolymer or copolymer.

[0067] According to the present invention, the molecular weight regulator is a conventional regulator in the art. For example, hydrogen, zinc alkyl, zinc alkoxide, magnesium alkyl, aluminum alkyl, ethylene, propylene, allene, 1,2 - butadiene, cyclooctadiene, or one or more of alcohols, thiols, amines, phenols and their salts can be selected.

[0068] According to the polymerization method of the present invention, the content of the trans - 1,4 - structure of the diene monomer unit in the obtained homopolymer or copolymer is 95 mol% or more, for example 98 mol% or more, and even up to 99 mol% or more, and the weight - average molecular weight is 0.05 - 200×10 4 。

[0069] The catalyst of the present invention is applied to the polymerization of dienes, especially the homopolymerization of isoprene, butadiene, and piperylene, the copolymerization of butadiene - isoprene, butadiene - piperylene, isoprene - piperylene, or the copolymerization of any one of the above - mentioned diene monomers with any one or more of styrene, ethylene, propylene, and butene.

[0070] The outstanding feature of the catalyst of the present invention for the polymerization of dienes is that the polymerization catalytic efficiency of the catalyst prepared with the magnesium chloride alcohol complex of the present invention as the carrier precursor is greatly improved compared with the catalyst with the traditional anhydrous magnesium chloride as the carrier precursor, reaching 50 - 500 Kg polymer / gram of transition metal / hour. The content of the trans - 1,4 - structure of the diene monomer unit in the homopolymer or copolymer is 95 mol% or more, and even up to 99 mol% or more, and the weight - average molecular weight is 0.05 - 200×10 4 。 Description of the Drawings

[0071] Figure 1 Shows the scanning electron microscope (SEM) image of the magnesium chloride alcohol complex carrier precursor prepared in Example 1;

[0072] Figure 2 Shows the scanning electron microscope (SEM) image of the solid catalyst particles prepared in Example 1. Detailed Description of the Invention

[0073] The present invention will be further described below in conjunction with specific embodiments. These embodiments are only used to illustrate the present invention and do not limit the scope of the present invention. In addition, after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, which also fall within the scope defined by the appended claims of this application.

[0074] Unless otherwise specified, the methods and equipment used in the present invention are conventional methods and equipment in the art.

[0075] The test conditions are as follows:

[0076] The titanium element content (wt%) in the catalyst is determined by an ultraviolet spectrophotometer.

[0077] The vanadium and aluminum element contents (wt%) in the catalyst are determined by an inductively coupled plasma spectrometer (ICP spectrometer).

[0078] The specific surface area, average pore diameter and porosity of the magnesium chloride alcoholate carrier precursor and the catalyst are obtained according to nitrogen adsorption / desorption experiments and high-pressure mercury intrusion methods.

[0079] The catalytic activity is calculated according to the following formula:

[0080] CA = W 聚合物 / W 过渡金属 *10 -3 *t -1 , kg 聚合物 ·(g 过渡金属 ) -1 ·h -1 , where CA is the catalytic activity of the catalyst, W 聚合物 is the mass of the polymerization product (g), W 过渡金属 is the amount of the transition metal in the catalyst (g), and t is the polymerization time (h).

[0081] The trans structure content (trans-1,4) and butadiene unit content (F Bd ) of the polymer are calculated from the 1 1H-NMR spectrum.

[0082] The weight-average molecular weight (M w ) and molecular weight distribution (M w / M n ) are characterized by gel permeation chromatography.

[0083] Example 1

[0084] 1) Preparation of the carrier precursor:

[0085] In a stirred reactor that has been treated under anhydrous and anaerobic conditions, anhydrous magnesium chloride and n-decane are added in a mass ratio of 1:20, and stirred and dispersed at 500 revolutions per minute for 5 minutes. Then, the temperature is raised to 60 °C at a heating rate of 50 °C per minute. Ethanol is added in a mass ratio of anhydrous MgCl2 to ethanol of 1:5, and the temperature is raised to 120 °C at a heating rate of 50 °C per minute, and the reaction is carried out at a constant temperature for 2 hours until the MgCl2 is completely dissolved into a transparent solution;

[0086] Subsequently, the system is quickly transferred to a low-temperature medium at -30 °C for cooling. During the cooling process, it is stirred at 2000 revolutions per minute. After cooling to -30 °C, stirring is maintained for 5 minutes. n-Heptane at -30 °C is added to the stirred reactor, and the mass ratio of MgCl2 to n-heptane is 1:25. Stirring is continued at 2000 revolutions per minute for 30 minutes. After a large number of solid particles precipitate, the solid particles are filtered out. The solid particles are washed and filtered with n-heptane (the mass ratio of MgCl2 to n-heptane is 1:25), and the washing and filtering are repeated 2 times;

[0087] The washed solid particles are heated from 30 °C at a heating rate of 10 °C per minute in a gradient manner (each gradient interval is 30 °C) to 120 °C and kept at a constant temperature for 120 minutes at each gradient. During the heating process, the vacuum degree is maintained at -0.05 Mpa. At 120 °C and a pressure of -0.05 Mpa, it is kept at a constant temperature and pressure for another 120 minutes to obtain a dried magnesium chloride alcoholate carrier precursor.

[0088] After testing, the average specific surface area of the magnesium chloride alcoholate carrier precursor is 49 m 2 / g, the average pore diameter is 201 nm, and the porosity is 62%. The scanning electron microscope (SEM) image of the magnesium chloride alcoholate carrier precursor is shown in Figure 1 .

[0089] 2) Preparation of solid catalyst particles:

[0090] In a stirred reactor that has been treated under anhydrous and anaerobic conditions, the above-mentioned magnesium chloride alcoholate carrier precursor and n-heptane are added, and the mass ratio of the magnesium chloride alcoholate carrier precursor to n-heptane is 1:20. At room temperature, the carrier precursor suspension is stirred and dispersed at a stirring speed of 500 revolutions per minute for 10 minutes. The reactor is cooled to -20 °C, and titanium tetrachloride is slowly added dropwise to the carrier suspension at -20 °C at a dropping rate of 5 ml per minute. The mass ratio of the magnesium chloride alcoholate carrier precursor to titanium tetrachloride is 1:20. After the dropping is completed, the reactor is heated to 130 °C at a heating rate of 2 °C per minute and reacted for 1 hour, and the liquid is filtered off;

[0091] Subsequently, after adding the same amount of titanium tetrachloride as above to the reactor, the reactor is heated to 130 °C at a heating rate of 2 °C per minute and reacted for 1 hour, and the liquid is filtered off;

[0092] Finally, n - heptane was added to the reactor (the mass ratio of the magnesium chloride alcohol complex carrier precursor to n - heptane was 1:20), and the mixture was stirred and washed at a speed of 500 revolutions per minute for 10 min at 50 °C, filtered and washed, and the process was repeated 5 times. The obtained powdered solid was vacuum - dried at 50 °C for 2 h to obtain solid catalyst particles with MgCl₂ as the carrier.

[0093] After testing, the average specific surface area of the solid catalyst particles was 52 m 2 ² / g, the average pore diameter was 235 nm, and the porosity was 66%. The scanning electron microscope (SEM) image of the solid catalyst particles is shown in Figure 2 .

[0094] 3) Pretreatment of the solid catalyst particles:

[0095] At room temperature, the above - mentioned solid catalyst particles were added to toluene, where the mass ratio of the solid catalyst particles to toluene was 1:1. The solid particle suspension was dispersed at a stirring speed of 500 revolutions per minute at room temperature for 10 min. Then the above suspension was cooled to 10 °C, and triethylaluminum was added, where the molar ratio of aluminum element to titanium element loaded on the solid catalyst particles was 2:1. The reaction was carried out at a constant temperature for 10 minutes. Then, a butadiene - isoprene mixture was introduced, where the molar ratio of the monomer to titanium element was 20:1, and the molar ratio of butadiene to isoprene was 0.1:1. The reaction was carried out at 10 °C for 10 minutes, filtered and vacuum - dried at 70 °C for 2 h to obtain pretreated catalyst particles. The characterization of the pretreated catalyst particles is shown in Table 1.

[0096] 4) Butadiene - isoprene copolymerization:

[0097] The above - mentioned pretreated catalyst particles were used for butadiene - isoprene copolymerization: Butadiene - isoprene mixed monomers (the molar ratio of titanium element to monomer was 3×10 -5 ⁻³:1, and the molar ratio of butadiene monomer to isoprene monomer was 6:94), triethylaluminum (the molar ratio of triethylaluminum to titanium element in the catalyst was 80:1), the pretreated catalyst particles, and molecular weight regulator hydrogen (the molar ratio of hydrogen to monomer was 1:400) were successively added to a reactor that had been pretreated with anhydrous and anaerobic conditions, and the reaction was carried out at 30 °C for 1 h. Subsequently, absolute ethanol was added to the reactor to terminate the polymerization, and the polymer was dried in a vacuum drying oven to a constant weight to obtain a butadiene - isoprene copolymer.

[0098] The catalyst, polymerization parameters, and results are shown in Table 1.

[0099] Example 2

[0100] 1) Preparation of the carrier precursor:

[0101] In a stirred reactor that has undergone anhydrous and anaerobic treatment, anhydrous magnesium chloride and paraffin oil are added in a mass ratio of 1:1. Stirring is started at 500 revolutions per minute for 60 min to achieve uniform dispersion. The temperature is increased at a rate of 40 °C per minute to 80 °C. Ethanol is added in a mass ratio of anhydrous MgCl2 to ethanol of 1:20. Then, the temperature is increased again at a rate of 30 °C per minute to 150 °C, and the reaction is maintained at a constant temperature for 0.5 h until the MgCl2 is completely dissolved into a transparent solution;

[0102] Subsequently, the system is quickly transferred to a 0 °C medium for cooling. After maintaining stirring at 8000 revolutions per minute for 5 min, n-hexane at 0 °C is added to the stirred reactor, where the mass ratio of MgCl2 to n-hexane is 1:100. Stirring is continuously carried out at 8000 revolutions per minute for 10 min. After a large number of solid particles precipitate, the solid particles are filtered out. The solid particles are washed with n-hexane (the mass ratio of MgCl2 to n-hexane is 1:100), filtered, and the washing and filtering are repeated once;

[0103] The washed solid particles are heated from 30 °C at a rate of 50 °C per minute in a gradient manner (each gradient interval is 10 °C) to 100 °C and held at a constant temperature for 400 min at each gradient. During the heating process, the vacuum degree is maintained at -0.01 Mpa. At 100 °C and a pressure of -0.01 Mpa, it is held at a constant temperature and pressure for another 400 min to obtain a dried magnesium chloride alcoholate carrier precursor.

[0104] After testing, the average specific surface area of the magnesium chloride alcoholate carrier precursor is 63 m 2 / g, the average pore diameter is 249 nm, and the porosity is 71%.

[0105] 2) Preparation of solid catalyst particles:

[0106] The mass ratio of the magnesium chloride alcoholate carrier precursor to titanium tetrachloride is 1:40, and the others are the same as in Example 1.

[0107] After testing, the average specific surface area of the solid catalyst particles is 65 m 2 / g, the average pore diameter is 301 nm, and the porosity is 76%.

[0108] 3) Pretreatment of solid catalyst particles:

[0109] It is the same as in Example 1, except that triethylaluminum is changed to triisobutylaluminum. The characterization of the pretreated catalyst particles is shown in Table 1.

[0110] 4) Copolymerization of butadiene and isoprene:

[0111] It is the same as in Example 1. The catalyst, polymerization parameters, and results are shown in Table 1.

[0112] Example 3

[0113] 1) Preparation of carrier precursor:

[0114] Same as Example 2, except that anhydrous magnesium chloride is changed to a mixture of anhydrous magnesium chloride / anhydrous vanadium tetrachloride with a mass ratio of 1:1.

[0115] 2) Preparation of solid catalyst particles:

[0116] In a stirred reactor that has undergone anhydrous and anaerobic treatment, add the above-mentioned carrier precursor and xylene, where the mass ratio of the carrier precursor to xylene is 1:20. Stir the carrier precursor suspension at a stirring speed of 1000 revolutions per minute at room temperature for 20 min for dispersion. Cool the reactor to -20 °C, and slowly dropwise add titanium tetrachloride to the carrier suspension at -20 °C at a dropping rate of 5 ml / min. The mass ratio of the carrier precursor to titanium tetrachloride is 1:40. After the dropping is complete, heat the reactor at a heating rate of 2 °C / min to 70 °C, add ethyl benzoate and react at a constant temperature for 30 min. The molar ratio of ethyl benzoate to the carrier precursor is 0.1. After the reaction is completed, heat the reactor at a heating rate of 2 °C / min to 110 °C and react for 1 h, then filter;

[0117] Subsequently, add the same amount of titanium tetrachloride as above to the reactor, then heat the reactor at a heating rate of 2 °C / min to 110 °C and react for 1 h, then filter;

[0118] Finally, add xylene (the mass ratio of the carrier precursor to xylene is 1:20) to the reactor, stir and wash at a speed of 500 revolutions per minute at 50 °C for 10 min, filter and wash, repeat 5 times, and vacuum-dry the obtained powder solid at 80 °C for 2 h to obtain solid particles.

[0119] After testing, the average specific surface area of the solid catalyst particles is 70 m 2 / g, the average pore diameter is 291 nm, and the porosity is 70%.

[0120] 3) Pretreatment of solid catalyst particles:

[0121] At room temperature, the above solid catalyst particles were added to toluene, where the mass ratio of the solid catalyst particles to toluene was 1:1. The solid particle suspension was dispersed at a stirring speed of 500 revolutions per minute for 10 min at room temperature. The above suspension was cooled to 0 °C, and diisobutylaluminum chloride was added, where the molar ratio of aluminum element to transition metal element was 6:1. The reaction was carried out at a constant temperature for 10 minutes, and a butadiene-isoprene mixture was introduced, where the molar ratio of the monomer to the transition metal element was 5:1, and the molar ratio of butadiene to isoprene was 0.5:1. The reaction was carried out at a constant temperature of 0 °C for 10 minutes, filtered and vacuum dried at 70 °C for 2 h to obtain pretreated catalyst particles. The characterization of the pretreated catalyst particles is shown in Table 1.

[0122] 4) Butadiene-isoprene copolymerization:

[0123] Same as Example 1. The catalyst, polymerization parameters and results are shown in Table 1.

[0124] Example 4

[0125] 1) Preparation of the carrier precursor:

[0126] In a stirred reactor that had been treated under anhydrous and anaerobic conditions, anhydrous magnesium chloride and n-nonane were added in a mass ratio of 1:50. Stirring was started at 500 revolutions per minute for 10 min, and the temperature was raised to 60 °C at a heating rate of 20 °C per minute. Ethanol was added in a mass ratio of anhydrous MgCl2 to ethanol of 1:2, and the temperature was again raised to 150 °C at a heating rate of 20 °C per minute. The reaction was carried out at a constant temperature for 1 h until the MgCl2 was completely dissolved into a transparent solution;

[0127] Subsequently, the system was quickly transferred to a low-temperature medium at -50 °C for cooling. After maintaining stirring at 2000 revolutions per minute for 5 min, n-octane at -50 °C was added to the stirred reactor. The mass ratio of MgCl2 to n-octane was 1:25. Stirring was continued at 2000 revolutions per minute for 10 min. After a large amount of solid particles precipitated, the solid particles were filtered to obtain solid particles. The solid particles were washed and filtered with n-octane (the mass ratio of MgCl2 to n-octane was 1:25), and the washing and filtering were repeated 3 times;

[0128] The washed solid particles were heated from 30 °C at a heating rate of 1 °C per minute in a gradient manner (each gradient interval was 45 °C) to 120 °C and held at a constant temperature for 540 min at each gradient. The vacuum degree was maintained at -0.02 Mpa during the heating process. At 120 °C and a pressure of -0.02 Mpa, the temperature and pressure were maintained at a constant value for another 540 min to obtain a dried magnesium chloride alcoholate carrier precursor.

[0129] The average specific surface area of the magnesium chloride alcoholate carrier precursor was tested to be 39 m 2 / g, the average pore diameter was 850 nm, and the porosity was 35%.

[0130] 2) Preparation of solid catalyst particles:

[0131] Same as Example 1.

[0132] After testing, the average specific surface area of the solid particles is 34 m 2 / g, the average pore diameter is 883 nm, and the porosity is 33%.

[0133] 3) Pretreatment of solid catalyst particles:

[0134] At room temperature, add the above solid catalyst particles to xylene, where the mass ratio of the solid catalyst particles to xylene is 1:5. Disperse the catalyst particle suspension at a stirring speed of 500 revolutions per minute at room temperature for 10 min, filter and vacuum dry at 80 °C for 2 h to obtain the pretreated catalyst particles. The characterization of the pretreated catalyst particles is shown in Table 1.

[0135] 4) Copolymerization of butadiene and isoprene:

[0136] Same as Example 1. The catalyst, polymerization parameters and results are shown in Table 1.

[0137] Comparative Example 1

[0138] 1) Preparation of carrier precursor:

[0139] Heat the washed solid particles from 30 °C to 120 °C at a heating rate of 10 °C / min (non-gradient heating). Maintain the vacuum degree at -0.05 Mpa during the heating process. Keep the temperature and pressure constant at 120 °C and -0.05 Mpa for 120 min to obtain the dried magnesium chloride alcoholate carrier precursor. The rest is the same as Example 1.

[0140] After testing, the average specific surface area of the magnesium chloride alcoholate carrier precursor is 26 m 2 / g, the average pore diameter is 140 nm, and the porosity is 44%.

[0141] 2) Preparation of solid catalyst particles:

[0142] Same as Example 1.

[0143] After testing, the average specific surface area of the solid catalyst particles is 35 m 2 / g, the average pore diameter is 209 nm, and the porosity is 49%.

[0144] 3) Pretreatment of solid catalyst particles:

[0145] Same as Example 1. The characterization of the pretreated catalyst particles is shown in Table 1.

[0146] 4) Butadiene-isoprene copolymerization:

[0147] Same as Example 1. The catalyst, polymerization parameters and results are shown in Table 1.

[0148] Comparative Example 2

[0149] 1) Preparation of solid catalyst particles:

[0150] Referring to Example 2 of Patent CN 113773426A (where the magnesium salt used is anhydrous MgCl2, the titanium solution is TiCl4, the liquid alkane is n-heptane, the solid alkane is solid paraffin, and the alkyl aluminum is triethyl aluminum), using traditional anhydrous magnesium chloride as the carrier precursor, physically grinding method is used to load TiCl4 onto the surface of MgCl2 to obtain solid catalyst particles.

[0151] After testing, the average specific surface area of the solid catalyst particles is 70 m 2 / g, the average pore diameter is 480 nm, and the porosity is 50%.

[0152] 2) Pretreatment of solid catalyst particles:

[0153] Same as Example 1. The characterization of the pretreated catalyst particles is shown in Table 1.

[0154] 3) Butadiene-isoprene copolymerization:

[0155] Same as Example 1. The catalyst, polymerization parameters and results are shown in Table 1.

[0156] Table 1 Example data

[0157]

[0158] Obviously, the above examples are only for clear illustration and not limitations on the implementation methods. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all implementation methods here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A catalyst for the trans - directed polymerization of dienes, wherein, The catalyst comprises a transition metal compound, magnesium chloride MgCl₂, an optional alkylaluminum compound, an optional electron donor, and other organic compounds. Based on the total mass of the catalyst, the content of the transition metal element is 0.1 - 8.0 wt%, the content of MgCl₂ is 15 - 30 wt%, the content of aluminum element is 0 - 10 wt%, the content of the electron donor is 0 - 20 wt%, and the content of other organic compounds is 0 - 10 wt%.

2. The catalyst according to claim 1, wherein, the transition metal compound is one or more selected from compounds of titanium and vanadium, specifically one or more selected from TiCl₄, TiBr₄, TiI₄, VCl₃, VBr₃, VOCl₃, VOBr₃, VCl₄, VBr₄, V₂O₅; the alkylaluminum compound is an alkylaluminum complexed on the surface of the catalyst, and the alkylaluminum is selected from one or more of triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, diisobutylaluminum chloride, dihexylaluminum chloride, dioctylaluminum chloride; the other organic compounds are selected from one or more of n - hexane, cyclohexane, n - heptane, cycloheptane, n - octane, isooctane, toluene, xylene, low - molecular - weight trans - 1,4 - polyisoprene, low - molecular - weight trans - 1,4 - polybutadiene, low - molecular - weight trans - 1,4 - butadiene - isoprene copolymer, low - molecular - weight trans - 1,4 - piperylene, low - molecular - weight trans - 1,4 - butadiene - piperylene copolymer, wherein the molecular weight of the low - molecular - weight polymer is less than 1000; the electron donor is one or more selected from ester compounds, ether compounds, and siloxane compounds.

3. The catalyst according to claim 1, wherein, the transition metals include V and Ti, and the molar ratio of V to Ti is 0 - 1:

1.

4. The catalyst according to claim 1, wherein, The catalyst is a solid particle with an average BET specific surface area of 30 to 70 m 2 / g, an average pore diameter of 40 to 1000 nm, and an average porosity of 30 - 80%; and / or the catalytic activity of the catalyst for diolefin polymerization reaches 50 - 500 Kg polymer / gram of transition metal / hour.

5. A method for preparing a catalyst, comprising the following steps: S1, Preparation of the carrier precursor, including: S1 - 1, Preparation of the metal chloride solution Add anhydrous MgCl₂ and a dispersion medium to an anhydrous and anaerobic reactor, stir and disperse, then heat up to 40 - 100 °C, add alcohol, and heat up again to 60 - 150 °C, and stir constantly until MgCl₂ is completely dissolved; S1 - 2, Preparation of the carrier particles Subsequently, transfer the system to a low - temperature medium at 0 °C - -80 °C for cooling, stir, add an inert solvent at the same temperature as the system temperature into the reactor, continue stirring until a large amount of solid particles precipitate, then filter and wash with the inert solvent to obtain solid particles; S1 - 3, Formation of the carrier precursor The solid particles are heated from 30°C to 40 - 250°C at a heating rate of 1 - 50°C per minute in a gradient manner, with each gradient interval being 5 - 50°C, and held at a constant temperature for 30 - 600 min at each gradient. During the heating process, the vacuum degree is maintained at -0.01 - -0.5 Mpa. At the final temperature of 40 - 250°C, it is held at a constant temperature and pressure of -0.01 - -0.5 Mpa for another 30 - 600 min to obtain the carrier precursor; S2, Preparation of solid catalyst particles, including: S2-1, Under anhydrous and anaerobic conditions at room temperature, the carrier precursor prepared in S1 is added to an inert solvent, and stirred at room temperature for dispersion to obtain a suspension; S2-2, The suspension obtained in S2-1 is cooled to -80 - 0°C, and a transition metal compound is added dropwise to the suspension at this temperature. The mass ratio of the transition metal compound to the carrier precursor is 2:1 - 100:1; then it is heated to 110 - 180°C and held for reaction, and filtered; Optionally, during the heating process, an electron donor is added at 55 - 120°C and held for reaction, and then heated to 110 - 180°C and held for reaction, and filtered; S2-3, The same amount of transition metal compound as in S2-2 is added to the reactor, the reactor is heated to 110 - 180°C, after reaction, it is filtered; S2-4, An inert solvent is added to the reactor, stirred at -20 - 80°C, filtered and washed, and the obtained powder solid is dried under vacuum to obtain solid catalyst particles; S3, Pretreatment of solid catalyst particles: At room temperature, the solid catalyst particles obtained in step S2 are added to an inert solvent, stirred at room temperature for dispersion to obtain a suspension, filtered and dried under vacuum to obtain pretreated catalyst particles; Optionally, the above suspension is cooled to -10 - 20°C, an alkyl aluminum is added, and optionally a single or mixed diene monomer is introduced, and held for reaction at -10 - 20°C, filtered and dried under vacuum to obtain the pretreated catalyst.

6. According to the method of claim 5, wherein, In the preparation S1 of the carrier precursor, In S1-1, stirred and dispersed at a speed of 10 - 1000 revolutions per minute for 5 - 100 min, and heated at a rate of 1 - 50°C per minute; and / or In S1-1, the alcohol used is one or more of saturated or unsaturated alcohols containing 1 - 20 carbon atoms, and the mass ratio of anhydrous MgCl2 to the alcohol is 1:1 - 1:100; and / or In S1-1, anhydrous MgCl2 is added alone to the anhydrous and anaerobic reactor or anhydrous MgCl2 and part of the transition metal compound (preferably vanadium compound, such as vanadium tetrachloride) are added to the reactor together; and / or In S1-2, stirred at a speed of 50 - 10000 revolutions per minute, where the mass ratio of anhydrous MgCl2 to the inert solvent is 1:1 - 1:100; and / or In S1-2, the inert solvent used is one or more selected from n-hexane, cyclohexane, n-heptane, cycloheptane, n-octane, isooctane, toluene, xylene; and / or In S1-3, the obtained carrier precursor is a magnesium chloride alcoholate with a structure of MgCl2·nROH, where R is a C1-C20 alkyl group and n is 0.01 - 6; In particular, in the preparation S1 of the carrier precursor, it includes: S1-1, adding anhydrous MgCl2 or its combination with a vanadium compound and a dispersion medium into an anhydrous and anaerobic reactor, stirring and dispersing at a speed of 10 - 1000 revolutions per minute for 5 - 100 min, heating up to 40 - 100 °C at a heating rate of 1 - 50 °C per minute, adding alcohol, and then heating up to 60 - 150 °C again at a heating rate of 1 - 50 °C per minute, and keeping stirring at a constant temperature for 0.5 - 5 h until MgCl2 is completely dissolved; S1-2, transferring the system to a low-temperature medium of 0 °C to -80 °C for cooling, stirring at a speed of 50 - 10000 revolutions per minute for 0.5 - 30 min, adding an inert solvent at the same temperature as the system temperature into the reactor, where the mass ratio of anhydrous MgCl2 to the inert solvent is 1:1 - 1:100, continuously stirring until a large amount of solid particles precipitate, then filtering to obtain solid particles, and washing the solid particles with an excessive amount of inert solvent 1 - 3 times; S1-3, heating the solid particles from 30 °C to 40 - 250 °C at a heating rate of 1 - 50 °C per minute in a gradient manner and keeping at a constant temperature for 30 - 600 min at each gradient, maintaining the vacuum degree at -0.01 - -0.5 Mpa during the heating process, and keeping at a constant temperature and pressure at 40 - 250 °C and -0.01 - -0.5 Mpa for another 30 - 600 min to obtain the carrier precursor.

7. According to the method described in claim 5 or 6, wherein, In the preparation S2 of the solid catalyst particles, In S2-1, the mass ratio of the carrier precursor to the inert solvent is 1:1 - 1:100; and / or In S2-2, the dropping rate of the transition metal is 1 - 50 ml / minute, and the mass ratio of the transition metal compound to the magnesium chloride alcoholate carrier precursor is 10:1 - 50:1; and / or In S2-2, the electron donor is one or more selected from ester compounds, ether compounds, and siloxane compounds, such as ethyl benzoate; and / or In S2-2 and S2-3, heat up at a heating rate of 0.1 - 50 °C per minute respectively; and / or In S2-4, the mass ratio of the carrier precursor to the inert solvent is 1:1 - 1:100, and / or, In S2-4, the obtained powder solid is vacuum dried at 40 - 80 °C for 0.1 - 5 h; In particular, in the preparation S2 of the solid catalyst particles, it includes: S2-1, adding the carrier precursor prepared above into an inert solvent under anhydrous and anaerobic conditions at room temperature, where the mass ratio of the carrier precursor to the inert solvent is 1:1 - 1:100, and dispersing the carrier precursor suspension at a stirring speed of 50 - 10000 revolutions per minute at room temperature for 5 - 30 min; S2-2. Cool the suspension obtained in S2-1 to -80 to 0 °C. At this temperature, add a transition metal compound dropwise to the suspension at a dropping rate of 1 to 50 ml / min. After the addition is complete, heat the reactor at a heating rate of 0.1 to 50 °C / min to 110 to 180 °C and carry out a constant-temperature reaction for 0.01 to 10 hours, then filter; if necessary, add an electron donor at 55 to 120 °C during the heating process and carry out a constant-temperature reaction for 5 to 60 min, and then heat at a heating rate of 0.1 to 50 °C / min to 110 to 180 °C and carry out a constant-temperature reaction for 0.01 to 10 hours, then filter; S2-3. Add the same amount of transition metal compound as in S2-2 to the reactor. Heat the reactor at a heating rate of 0.1 to 50 °C / min to 110 to 180 °C, react for 0.01 to 10 hours, then filter; S2-4. Add an inert solvent to the reactor. The mass ratio of the carrier precursor to the inert solvent is 1:1 to 1:

100. Stir at a speed of 50 to 10,000 revolutions per minute at -20 to 80 °C for 5 to 60 min, filter and wash, repeat 5 times. The obtained powder solid is vacuum dried at 40 to 80 °C for 0.1 to 5 h to obtain solid catalyst particles with MgCl2 as the carrier; In particular, the transition metal compound is one or more selected from compounds of titanium and vanadium, specifically one or more selected from TiCl4, TiBr4, TiI4, VCl3, VBr3, VOCl3, VOBr3, VCl4, VBr4, V2O5; 8. According to the method according to any one of claims 5 to 7, wherein, in the pretreatment S3 of the solid catalyst particles, the molar ratio of aluminum element to transition metal element is 0.1 to 10:1; and / or in the pretreatment S3 of the solid catalyst particles, the molar ratio of the monomer to the transition metal element is 0.1 to 100:

1. If the monomer is a mixture of two monomers, the molar ratio of the monomers in the monomer mixture is 0.1:1 to 10:1; and / or in the pretreatment S3 of the solid catalyst particles, the diolefin monomer is butadiene or isoprene or pentadiene or a butadiene-isoprene mixture or a butadiene-pentadiene mixture. In particular, the molar ratio of the monomers in the monomer mixture is 0.1:1 to 10:1; and / or in the pretreatment S3 of the solid catalyst particles, the alkylaluminum is one or more selected from triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, diisobutylaluminum chloride, dihexylaluminum chloride, dioctylaluminum chloride; In particular, in the pretreatment S3 of the solid catalyst particles, it includes: At room temperature, the solid catalyst particles obtained in step S2 are added to an inert solvent, where the mass ratio of the solid catalyst particles to the inert solvent is 1:1 to 1:

100. At room temperature, the solid particle suspension is dispersed at a stirring speed of 50 to 10,000 revolutions per minute for 5 to 30 minutes, filtered and vacuum dried at 40 to 80 °C for 0.1 to 5 hours to obtain pretreated catalyst particles; if necessary, the above suspension is cooled to -10 to 20 °C, and an alkylaluminum is added, where the molar ratio of aluminum element to transition metal element is 0.1 to 10:1, and the reaction is carried out at a constant temperature for 0.1 - 30 minutes. Optionally, butadiene or isoprene or pentadiene or a butadiene-isoprene mixture or a butadiene-pentadiene mixture is introduced, where the molar ratio of the monomer to the transition metal element is 0.1 to 100:1, and the reaction is carried out at a constant temperature of -10 to 20 °C for 0.1 - 30 minutes, filtered and vacuum dried at 40 to 80 °C for 0.1 to 5 hours to obtain pretreated catalyst particles; wherein the pretreated catalyst particles contain a transition metal compound, magnesium chloride MgCl2, an alkylaluminum compound, a donor and other organic compounds.

9. A catalyst prepared by the method according to claims 5 to 8. In particular, the content of transition metal titanium and / or vanadium element in the catalyst is 0.1 to 8.0 wt%, the content of magnesium chloride is 15 to 30 wt%, the content of aluminum element is 0 to 10 wt%, the content of the donor in the solid particles is 0 to 20 wt%, and the content of other organic compounds is 0 to 10 wt%.

10. Use of the catalyst according to any one of claims 1 to 4 or the catalyst according to claim 9 for the polymerization of dienes to prepare polyolefins with a high content of trans structure; or A method for the polymerization of dienes, comprising the following steps: Add monomers, alkylaluminum, the catalyst according to any one of claims 1 to 4 or the catalyst according to claim 9, and a molecular weight regulator into a reactor that has been pretreated under anhydrous and anaerobic conditions in sequence. The molar ratio of the transition metal element in the catalyst to the monomers is 0.001 to 100×10 -5 :1, the molar ratio of the alkylaluminum to the transition metal element in the catalyst is 5 to 800:1, the molar ratio of the molecular weight regulator to the monomers is 1:10 to 10000, and react at 10 to 70°C for 1 h; then add water or an alcohol terminator into the reactor to terminate the polymerization, and place the polymer in a vacuum drying oven to dry to a constant weight to obtain a diene homopolymer or copolymer; In particular, the content of the trans-1,4-structure of the diene monomer unit in the obtained homopolymer or copolymer is 95 mol% or more, for example, 98 mol% or more, and even up to 99 mol% or more, and the weight-average molecular weight is 0.05 to 200×10 4 ; In particular, the polymerization is the homopolymerization of isoprene, butadiene, pentadiene, the copolymerization of butadiene-isoprene, butadiene-pentadiene, isoprene-pentadiene, or the copolymerization of any one of the above diene monomers with any one or more of styrene, ethylene, propylene, butene.

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