阅读说明：本技术 后过渡金属催化剂催化烯烃均相聚合的气相聚合法 (Gas phase polymerization method for catalyzing olefin homogeneous polymerization by late transition metal catalyst ) 是由 陈昶乐 代胜瑜 于 2020-05-13 设计创作，主要内容包括：本发明涉及一种后过渡金属催化剂催化烯烃均相聚合的气相聚合方法,包括：将后过渡金属催化剂与助催化剂以1∶1～1∶3摩尔比的混合物溶解在挥发性有机溶剂中以形成催化剂溶液；将所得的催化剂溶液装入压力反应器中并使其均匀地涂布在所述压力反应器的壁上,从而在所述挥发性有机溶剂挥发后在所述壁上形成催化剂膜层；通入烯烃气体并在在1～10个大气压的反应压力和20～80℃的反应温度下使烯烃与催化剂膜层接触反应,从而获得所需的烯烃聚合物。利用本发明所述的均相气相聚合法可以合成性能优异的聚烯烃材料,并且能够通过控制聚合条件来调控聚烯烃材料的机械性能。此外,本发明的均相气相聚合法显著减少有机溶剂的使用,属于经济且环境友好型烯烃聚合方式。(The invention relates to a gas-phase polymerization method for catalyzing olefin homogeneous polymerization by using a late transition metal catalyst, which comprises the following steps: dissolving a mixture of a late transition metal catalyst and a cocatalyst in a molar ratio of 1: 1-1: 3 in a volatile organic solvent to form a catalyst solution; charging the resulting catalyst solution into a pressure reactor and uniformly coating it on the wall of the pressure reactor, thereby forming a catalyst membrane layer on the wall after the volatile organic solvent is volatilized; and introducing olefin gas, and enabling the olefin to contact and react with the catalyst film layer at the reaction pressure of 1-10 atmospheric pressures and the reaction temperature of 20-80 ℃, thereby obtaining the required olefin polymer. The homogeneous gas phase polymerization method can synthesize polyolefin materials with excellent performance, and can regulate and control the mechanical properties of the polyolefin materials by controlling the polymerization conditions. In addition, the homogeneous gas phase polymerization method of the invention significantly reduces the use of organic solvents, and belongs to an economic and environment-friendly olefin polymerization mode.)

1. A gas phase polymerization process for the homogeneous polymerization of olefins catalyzed by a late transition metal catalyst, the gas phase polymerization process comprising:

dissolving a mixture of a late transition metal catalyst and a cocatalyst in a molar ratio of 1: 1-1: 3 in a volatile organic solvent to form a catalyst solution;

loading the obtained catalyst solution into a pressure reactor and uniformly coating the catalyst solution on the wall of the pressure reactor, thereby forming a catalyst membrane layer on the wall of the pressure reactor after the volatile organic solvent is volatilized; and

introducing olefin gas, and enabling the olefin to contact and react with the catalyst film layer under the reaction pressure of 1-10 atmospheric pressure and the reaction temperature of 20-80 ℃ so as to obtain the required olefin polymer,

wherein the content of the first and second substances,

the late transition metal catalyst is α -diimine palladium catalyst;

the cocatalyst is tetrakis (3, 5-bis (trifluoromethyl) phenyl) borate.

2. The gas phase polymerization process of claim 1, wherein the molar ratio of the late transition metal catalyst to the cocatalyst is from 1: 1.5 to 1: 2.5.

3. The gas-phase polymerization process of claim 1, wherein the α -diimine palladium-based catalyst is one or more of the following formulas 1-8:

wherein Me represents a methyl group and Ph represents a phenyl group.

4. The gas-phase polymerization process of claim 1, wherein the cocatalyst is sodium tetrakis (3, 5-bis (trifluoromethyl) phenyl) borate or potassium tetrakis (3, 5-bis (trifluoromethyl) phenyl) borate.

5. The gas-phase polymerization process of claim 1, wherein the olefin is gaseous α -olefin.

6. The gas-phase polymerization process of claim 5, wherein the gaseous α -olefin is ethylene, propylene, or 1-butene.

7. The gas-phase polymerization process of claim 5, wherein the gaseous α -olefin is ethylene.

8. The gas-phase polymerization process of claim 1, wherein the volatile organic solvent is dichloromethane or trichloromethane.

9. The gas-phase polymerization process according to claim 8, wherein 0.1 to 0.5m L of the volatile organic solvent is used based on 1. mu. mol of the late transition metal catalyst.

10. The gas-phase polymerization process according to claim 1, wherein the reaction time is 2 to 15 hours.

Technical Field

The invention relates to the field of synthetic high-molecular polyolefin materials, in particular to a gas-phase polymerization method for catalyzing olefin homogeneous polymerization by using a late transition metal catalyst.

Background

Polyolefin materials are indispensable in production and living as well as industrial application, and have wide application. Since the discovery of heterogeneous titanium and chromium catalysts in the 1950 s, the polyolefin industry has rapidly progressed, and by 2015 the global production of polyolefin has reached 1.78 billion tons, making the polyolefin industry a multi-billion dollar business. Because of the superior performance of heterogeneous systems in terms of product morphology control, avoidance of reactor fouling and applicability in continuous polymerization processes, the commercial production of polyolefins has been dominated by the use of heterogeneous systems such as Ziegler-Natta and Phillips catalysts; however, contrary to the heterogeneous catalytic polymerization system widely used in the polyolefin industry, the heterogeneous nature of the homogeneous system can provide a solution for the "plug and play" catalyst strategy in the existing industrial polyolefin synthesis, so the research focus of the researchers in the academic research of polyolefin, especially in the field of late transition metal catalysts, has been focused on the homogeneous system. Although the heterogeneous system catalytic polymerization process in the industry is quite mature, the existing methods need to use a large amount of organic solvent to serve as a reaction solvent and an eluent in the process flow, and have the problems that polyolefin needs to be dried and the like; this places high demands on the work-up process of the olefin polymerization industry and the resulting emission of organic waste streams has a large environmental impact.

Therefore, there is still a need in the art to provide an improved process for preparing polyolefin materials to simplify the process of preparing polyolefin materials while reducing the emission of organic waste streams in order to achieve a "green chemistry" compliant polyolefin synthesis.

Disclosure of Invention

In order to overcome one or more of the problems of the prior art, the present invention provides a gas phase polymerization method for the homogeneous polymerization of olefins using a late transition metal catalyst, which has a simple process and does not require the use of a large amount of organic solvents, and particularly, the gas phase polymerization process of olefins does not involve the discharge of organic waste liquid at all, thereby realizing the synthesis of polyolefins meeting the "green chemistry" requirements.

In view of this, the present invention provides a gas phase polymerization process for the homogeneous polymerization of olefins catalyzed by a late transition metal catalyst, the gas phase polymerization process comprising:

dissolving a mixture of a late transition metal catalyst and a cocatalyst in a molar ratio of 1: 1-1: 3 in a volatile organic solvent to form a catalyst solution;

loading the obtained catalyst solution into a pressure reactor and uniformly coating the catalyst solution on the wall of the pressure reactor, thereby forming a catalyst membrane layer on the wall of the pressure reactor after the volatile organic solvent is volatilized; and

introducing olefin gas and reacting at a reaction pressure of 1-10 atm and a reaction temperature of 20-80 ℃ to obtain the desired olefin polymer,

wherein the content of the first and second substances,

the late transition metal catalyst is α -diimine palladium catalyst;

the cocatalyst is tetrakis (3, 5-bis (trifluoromethyl) phenyl) borate.

In a preferred embodiment, the molar ratio of the late transition metal catalyst to the cocatalyst is 1: 1.5 to 1: 2.5.

In a preferred embodiment, the α -diimine palladium catalyst is one or more of the following formulas 1-8:

wherein Me represents a methyl group and Ph represents a phenyl group.

In a preferred embodiment, the cocatalyst is sodium tetrakis (3, 5-bis (trifluoromethyl) phenyl) borate or potassium tetrakis (3, 5-bis (trifluoromethyl) phenyl) borate.

In a preferred embodiment, the olefin is gaseous α -olefin, preferably the gaseous α -olefin is ethylene, propylene or 1-butene, more preferably ethylene.

In a preferred embodiment, the volatile organic solvent is dichloromethane or trichloromethane.

In a further preferred embodiment, 0.1 to 0.5m L of the volatile organic solvent is used, based on 1. mu. mol of the late transition metal catalyst.

In a preferred embodiment, the reaction time is 2 to 15 hours.

The beneficial effects of the present invention include, but are not limited to, the following aspects:

in the gas phase polymerization process of the present invention, a catalyst film layer is formed on the wall of a pressure reactor by using a specific late transition metal catalyst and a specific co-catalyst in a mixture of a specific ratio, and gaseous olefins are brought into contact with the catalyst film layer on the wall of the reactor for reaction. Because the catalyst membrane layer generates the porous polymer carrier, an organic liquid solvent or an additional solid material in the existing liquid phase method or gas-liquid two-phase method is not needed to be used as a polymerization carrier, and a quenching reaction step is not needed correspondingly, so that the production cost is greatly reduced, the process flow is simplified, and zero organic waste liquid discharge can be realized in the olefin polymerization process, thereby realizing the green chemical polyolefin synthesis.

In addition, compared with the existing liquid phase method or gas-liquid two-phase system polymerization method, the catalyst film layer formed by the method has a significantly larger contact surface area, so that the homogeneous polymerization of olefin can be completed more quickly, the required product can be directly obtained without post-treatment after the reaction, and the industrial production efficiency can be significantly improved.

In addition, with the gas phase polymerization method of the present invention, in the case of using a mixture of a specific late transition metal catalyst and a specific co-catalyst in a specific ratio, the microstructure of polyolefin can be controlled by controlling the olefin pressure and reaction temperature of the reaction, thereby obtaining polyolefins of different mechanical properties.

In addition, with the gas phase polymerization process of the present invention, a desired polyolefin product can be obtained in a higher yield, and the obtained polyolefin has a higher molecular weight and has good mechanical properties such as elongation at break, recovery rate, and the like.

Drawings

FIG. 1 shows the results of mechanical property tests of olefin polymers obtained by a gas phase polymerization method according to an example of the present invention, wherein (a) to (d) are elongation at break-stress graphs, and (e) to (h) are elastic recovery-stress graphs, and (a) and (e) are the test results of application example 5; (b) and (f) are test results of application example 6, (c) and (g) are test results of application example 13, and (d) and (h) are test results of application example 7.

Detailed Description

The inventors of the present invention have found, through extensive and intensive studies on olefin polymerization processes, that the post-transition metal catalysts exhibit different polymerization activities in different polymerization modes and the mechanical properties of the resulting polymers, and unexpectedly obtained a novel gas phase polymerization process of the present invention through studies on different polymerization modes of different post-transition metal catalysts and continuous optimization of design.

More specifically, the present invention forms a catalyst film layer on the wall of a reactor after the volatilization of a volatile organic solvent by using a mixture of a specific late transition metal catalyst and a specific co-catalyst in a specific ratio and forming the mixture into a catalyst solution that can be coated on the wall of the reactor with a very small amount of the volatile organic solvent. The formed catalyst membrane layer can form a porous polymer carrier, so that a metal center can be ensured to move along a polymer chain in the olefin polymerization process, and a proper site is found for effective olefin double bond bonding, so that an organic liquid solvent or an additional solid material is not required to be used as a polymerization carrier in the polymer polymerization process; meanwhile, the formed catalyst membrane layer has a significantly larger contact surface area, so that homogeneous polymerization of olefin can be more rapidly completed, and pure polyolefin product can be directly obtained without post-treatment such as precipitation, separation and drying required for liquid phase polymerization after the reaction.

The gas-phase polymerization method for catalyzing olefin homogeneous polymerization by using the late transition metal catalyst provided by the invention comprises the following steps: dissolving a mixture of a late transition metal catalyst and a promoter in a volatile organic solvent to form a catalyst solution; loading the obtained catalyst solution into a pressure reactor and uniformly coating the catalyst solution on the wall of the pressure reactor, thereby forming a catalyst membrane layer on the wall of the pressure reactor after the volatile organic solvent is volatilized; and introducing olefin gas, and reacting at a reaction pressure of 1-10 atm and a reaction temperature of 20-80 ℃ to obtain the required olefin polymer.

In the present invention, the post-transition metal catalyst used is α -diimine palladium-based catalyst and the cocatalyst used is tetrakis (3, 5-bis (trifluoromethyl) phenyl) borate, in the present invention, the mixing molar ratio of the post-transition metal catalyst to the cocatalyst is in the range of 1: 1 to 1: 3, preferably in the range of 1: 1.5 to 1: 2.5, for example, may be 1: 2 the inventors of the present invention have found that when the mixing molar ratio of the post-transition metal catalyst to the cocatalyst is lower than the above range, the catalyst activation is not thorough, the reaction rate is significantly reduced, and the mechanical properties of the obtained olefin polymer are poor, and when the mixing molar ratio of the post-transition metal catalyst to the cocatalyst is higher than the above range, part of the catalyst is deactivated, and the mechanical properties of the obtained olefin polymer are also poor.

In the present invention, the α -diimine palladium catalyst used may be one or more of the following formulas 1 to 8, and these catalysts may be obtained, for example, according to the literature ((1) Angew. chem. int. Ed.2015, 54, 9948-.

Wherein Me represents a methyl group and Ph represents a phenyl group.

In the present invention, preferably, as the co-catalyst, examples of tetrakis (3, 5-bis (trifluoromethyl) phenyl) borate that may be used include, but are not limited to, sodium tetrakis (3, 5-bis (trifluoromethyl) phenyl) borate or potassium tetrakis (3, 5-bis (trifluoromethyl) phenyl) borate, which is commercially available from Annaiji chemical company, for example, sodium tetrakis (3, 5-bis (trifluoromethyl) phenyl) borate having a product model number of E0609160250 may be used, for example.

In the present invention, before the olefin polymerization reaction is carried out, in order to form a desired catalyst film layer on the wall of the reactor, it is necessary to first mix the late transition metal catalyst and the cocatalyst at a molar ratio of 1: 1 to 1: 3, and then dissolve the resulting mixture in an appropriate amount of a volatile organic solvent to form a catalyst solution.

The inventors of the present invention have found that, as a volatile organic solvent, dichloromethane or trichloromethane is not only easily available and inexpensive, but also, when dichloromethane or trichloromethane is used as the volatile organic solvent of the present invention, it is possible to use, for the same amount of the above-mentioned mixture, significantly less amount of dichloromethane or trichloromethane than other volatile organic solvents, for example, only 0.1 to 0.5m L of the volatile organic solvent may be used based on 1. mu. mol of the late transition metal catalyst, accordingly, after the formed catalyst solution is applied to the reactor wall, such less amount of volatile solvent can be more rapidly volatilized and a more uniform catalyst film layer can be formed, thereby accelerating the entire reaction process, while correspondingly reducing possible solvent recovery problems or environmental pollution problems.

In the present invention, preferably the olefin used for the gas phase polymerization can be gaseous α -olefin, more preferably the gaseous α -olefin used is ethylene, propylene or 1-butene, most preferably ethylene.

In the gas-phase polymerization process of the present invention, an olefin gas such as ethylene is introduced so that the pressure in the pressure reactor is in the range of 1 to 10 atmospheres (atm), for example, 8atm, and at such a reaction pressure, the polymerization can be rapidly completed and an olefin polymer having desired mechanical properties can be obtained. In contrast, when the pressure is lower than 1 atmosphere, the reaction is too slow and the resulting polymer has poor mechanical properties; when the pressure is higher than 10 atmospheres, the reaction is too fast, and the mechanical properties of the obtained polymer are also poor.

In the gas phase polymerization process of the present invention, the polymerization reaction is carried out at a reaction temperature of 20 to 80 ℃, preferably at a normal temperature of 25 ℃. The inventors have found that when the reaction temperature is below 20 ℃, the reaction rate is too slow and the resulting polymer has poor mechanical properties; when the reaction temperature is higher than 80 ℃, the reaction rate is too high, so that the implosion phenomenon can be generated, and at the moment, a part of the active centers of the catalyst metal can be covered by the polymer generated by the implosion, which is not beneficial to the growth of molecular chains, even leads to the early termination of the polymerization, so that the molecular weight difference of the obtained polymer is large, and the mechanical property of the obtained polymer is poor.

In the present invention, the polymerization reaction time is usually 2 to 15 hours, for example, 12 hours under the above reaction conditions.

In the present invention, there is no particular requirement for the pressure reactor to be used as long as the polymerization reaction can be effected at the above-mentioned pressure and temperature. Preferably, the pressure reactor used may be a stainless steel autoclave, a thick-walled glass pressure reactor, or the like. In order to be able to monitor the progress of the reaction by eye, a transparent thick-walled glass pressure reactor is more preferable.

In the present invention, preferably, after the connection of the ethylene feed line to the reactor and before the application of the catalyst solution, the reactor is first dried under vacuum and preferably, for example, at 90 ℃ for a certain time, for example, over 1h, and then the reactor is kept at the desired reaction temperature, for example, by a water bath or an oil bath, before the application of the catalyst solution is carried out.

In the present invention, after the polymerization reaction is completed, the pressure reactor is vented to obtain a polymer.

It is understood that within the scope of the present invention, one or more, even all, of the individual features specifically described herein may be combined independently of each other to form new or preferred embodiments. For reasons of space, they will not be described in detail.