Preparation method of polyolefin

Abstract

The invention provides a preparation method of polyolefin. In the preparation method, a cycloolefin monomer is used as a gas phase, a catalyst is loaded on a substrate material, and the catalyst is a solid phase; carrying out gas-solid polymerization reaction on the cycloolefin monomer under the action of a catalyst to obtain polyolefin; and the loading capacity of the catalyst on the substrate material is 0.5-200ppm. The method provided by the invention overcomes the tedious operation in the prior art, and can obtain the polyolefin product with ultra-high molecular weight and narrow molecular weight distribution.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic synthesis, and particularly relates to a method for preparing polyolefins. Background Art

[0002] Ring-Opening Metathesis Polymerization (ROMP) is a living polymerization reaction and is widely used in the synthesis of polyolefin materials. In most cases, the polymerization reaction is carried out in solution. Affected by the chain transfer side reaction, the highest molecular weight that the obtained product can reach is limited. When the polymerization reaction is carried out in the gas phase, the movement of the polymer chains is restricted, the chain transfer side reaction is inhibited, and a product with a higher molecular weight can be obtained. By loading the catalyst on a solid substrate and polymerizing gaseous cycloolefin monomers, the obtained polycyclopentene can reach a number average molecular weight of more than 1 million, which exceeds three times the upper limit of the reported solution polymerization molecular weight, while maintaining a polydispersity index of less than 1.5 (ACS Macro Letters, 2017, 6, 2, 112-116). The obtained material can be hydrogenated to obtain ultra-high molecular weight and unbranched polyethylene. This polymerization method is applicable to many common monomers for ring-opening metathesis polymerization reactions, such as cyclopentene, cyclohexadiene, cycloheptene, norbornene, cyclooctene, 1,5-cyclooctadiene, cyclooctatetraene, 1,5,9-cyclododecatriene, etc. At the same time, because the use of solvents is avoided during the reaction process, the production cost and environmental pollution are reduced.

[0003] Previously reported similar technologies in the literature require additional surface treatment and cumbersome synthetic steps of catalyst bonding, and the catalyst loading is low, which affects the polymer yield (Langmuir, 2017, 23, 1004-1006; Langmuir 2011, 27, 5403-5409; Langmuir, 2017, 33, 13903-13912); or there is no monomer purification step before polymerization. In all reports, due to the insufficient amount of the obtained product for molecular weight detection, the characterization of the product molecular weight or polydispersity index is lacking. Summary of the Invention

[0004] To solve the above problems, the present invention provides a method for preparing polyolefins. The method of the present invention overcomes the cumbersome operations in the prior art, loads the catalyst on the substrate material in the reaction vessel, and carries out a gas-solid polymerization reaction, so as to obtain a polyolefin product with ultra-high molecular weight and narrow molecular weight distribution.

[0005] The present invention provides a method for preparing polyolefins, wherein a cycloolefin monomer is used as the gas phase, and the catalyst is loaded on the substrate material, and the catalyst is in a solid phase;

[0006] The cycloolefin monomer is subjected to a gas-solid polymerization reaction under the action of the catalyst to obtain the polyolefin;

[0007] The loading amount of the catalyst on the substrate material is 0.5 to 1000 ppm, preferably 0.5 to 50 ppm.

[0008] After adding a purified cycloolefin monomer that does not directly contact the substrate, the monomer volatilized in the gas phase contacts the solid-phase catalyst, and a gas-solid polymerization reaction occurs. A polyolefin product with ultra-high molecular weight and narrow molecular weight distribution can be obtained. By controlling the catalyst loading, the molecular weight of the product can be controlled. Using an efficient ROMP catalyst makes the reaction have the characteristics of living polymerization, and the polymerization reaction occurs at the gas-solid interface and the content of non-cycloolefin impurities after monomer purification is reduced, reducing the chain transfer side reaction during the polymerization process, and finally obtaining a polymerization product with a narrow molecular weight distribution.

[0009] After the reaction is completed, the product is peeled off from the substrate material to obtain the product.

[0010] In actual preparation operations, since the cycloolefin raw material may contain linear olefin impurities, these impurities will reduce the molecular weight of the product and broaden the molecular weight distribution as chain transfer reagents during the polymerization process. Therefore, it is very important to purify the monomer to remove the linear olefins. The methods for monomer purification include distillation and hydroboration, or a combination of both. In the hydroboration method, a borane molecule is added to the monomer. The borane has a higher reactivity with linear olefins. The hydroboration product obtained after the reaction has a high boiling point, is difficult to volatilize, and does not have reaction activity, so it will not affect the polymerization process. The borane molecule is shown in Formula 6, where R1 and R2 are the same or different C1-C20 hydrocarbon groups, and R1 and R2 may be connected to form a monocyclic or polycyclic group. The preferred borane is 9-borabicyclo[3.3.1]nonane (9-BBN). The addition amount of the borane depends on the content of linear olefin impurities in the monomer, and is preferably 5 to 20 times the molar amount of the impurities. The present invention preferably first purifies the monomer by distillation and then further reduces the impurity content by hydroboration.

[0011]

[0012] In a preferred embodiment of the present invention, the method for loading the catalyst includes:

[0013] The catalyst is configured with an organic solvent to form a catalyst solution, the catalyst solution is distributed on the substrate material, and then the organic solvent is removed.

[0014] In a preferred embodiment of the present invention, the organic solvent is one or a combination of two or more of linear aliphatic hydrocarbons, cyclic aliphatic hydrocarbons, and aromatic hydrocarbons. More preferably, the organic solvent is an aromatic hydrocarbon.

[0015] In a preferred embodiment of the present invention, the concentration of the catalyst solution is 1 to 2000 μmol / L. More preferably, the concentration of the catalyst solution is 5 to 600 μmol / L.

[0016] In a preferred embodiment of the present invention, the catalyst includes one or a combination of two or more of ruthenium ROMP catalysts, tungsten ROMP catalysts, molybdenum ROMP catalysts, and rhenium ROMP catalysts. More preferably, the catalyst is Grubbs 1st and / or Grubbs 2nd.

[0017] In a preferred embodiment of the present invention, the substrate material includes one of glass, silicon wafers, paper, aluminum foil, stainless steel, and plastics. Preferably, the substrate material is placed at the bottom of the reactor.

[0018] More preferably, the substrate material is glass or paper.

[0019] In a preferred embodiment of the present invention, the reaction temperature of the gas-solid polymerization reaction is -80 to 200 °C, and the reaction time is 30 min to 12 h. More preferably, the reaction temperature is 0 to 30 °C, and the reaction time is 1 to 6 h.

[0020] As the reaction temperature decreases, the molecular weight of the polymer increases.

[0021] In actual operation, preferably outside the reactor, a liquid medium is used to provide the reaction temperature.

[0022] By regulating the reaction temperature, the molecular weight of the product obtained by the preparation method of the present invention can be controlled.

[0023] In a preferred embodiment of the present invention, the cycloolefin monomer includes one or a combination of two or more of the cycloolefins shown in Formula 1, Formula 2, Formula 3, Formula 4, and Formula 5;

[0024]

[0025] wherein, n = 1, 3, 4 or 8.

[0026] In a preferred embodiment of the present invention, the method for removing the organic solvent includes: drying the organic solvent with an inert gas;

[0027] Preferably, the temperature of the inert gas is 0 to 50 °C. More preferably, the temperature of the inert gas is 20 to 30 °C.

[0028] Preferably, the inert gas is selected from nitrogen and / or argon.

[0029] In some embodiments of the present invention, the method for loading the catalyst includes a spin coating method.

[0030] The present invention also provides two reactors applicable to the preparation method of the present invention.

[0031] The schematic structural diagram of Reactor A is as Figure 1 shown, and the schematic structural diagram of Reactor B is as Figure 2 shown.

[0032] In Reactor A, there is a gasket 1 at the top of the outer bottle 5, which is fixedly sealed by a cover 2 with a hole in the middle. After the top of the inner bottle 4 is tied with a wire 3, the wire 3 passes through the gasket 1 and is fixed, hanging in the outer bottle 5.

[0033] In Reactor B, there is a gasket 1 at the top of the outer bottle 5, which is fixedly sealed by a cover 2 with a hole in the middle. The substrate 7 is provided with a hole and passed through by a wire 3, and the wire 3 passes through the gasket 1 and is fixed, so that the substrate 7 hangs in the outer bottle 5. The paper 6 is closely attached to the inner wall of the outer bottle 5 and contacts the bottom, accelerating the evaporation rate after being infiltrated with the monomer liquid.

[0034] The main body materials of Reactor A and Reactor B are glass.

[0035] The above-mentioned Reactor A and Reactor B are only for illustration, rather than a further limitation on the preparation method of the present invention.

[0036] The preparation method of the present invention can obtain polyolefins with ultra-high molecular weight. When those skilled in the art need a low product molecular weight, a certain amount of linear olefin can be added to the reaction monomer. Among them, the structural formula of the linear olefin is as shown in Formula 7. Wherein R3 and R4 are the same or different C1-C10 hydrocarbon groups or hydrogen. Those skilled in the art can determine the specific selection of the linear olefin and its addition amount based on the common general knowledge in the art and a limited number of experiments.

[0037]

[0038] Compared with the prior art, the present invention has the following advantageous effects: the preparation method of the present invention is relatively simple to operate, and can obtain polyolefin products with ultra-high molecular weight and narrow molecular weight distribution in a relatively high yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Shows the schematic structural diagram of Reactor A.

[0040] Figure 2 Shows the schematic structural diagram of Reactor B.

[0041] Figure 3 Shows the solid-state nuclear magnetic resonance carbon spectrum of the product obtained in Synthesis Example 1.

[0042] The markings in the figure include:

[0043] 1 - Pad, 2 - Cover, 3 - Iron wire, 4 - Inner bottle, 5 - Outer bottle, 6 - Paper, 7 - Base. Detailed implementation mode

[0044] For a clearer understanding of the technical features, objectives, and beneficial effects of the present invention, the technical solutions of the present invention are hereinafter described in detail, but it should not be construed as a limitation on the scope of implementation of the present invention.

[0045] In the following examples, the measurement of the number average molecular weight, weight average molecular weight, and molecular weight distribution coefficient is completed by a size exclusion gel chromatograph. The instrument consists of an Agilent 1260 liquid pump, two series-connected Agilent PLgel MIXED-B 300×7.5 mm chromatographic columns, a Wyatt 18-angle DAWN HELEOS light scattering detector, and a Wyatt Optilab rEX differential refractive index detector. Tetrahydrofuran is used as the solvent and mobile phase, with a concentration of 1 g / L and a flow rate of 1 mL / min.

[0046] In the following examples and comparative examples, reactor A has the structure as shown in Figure 1 shown, and reactor B has the structure as shown in Figure 2 shown.

[0047] In reactor A, there is a pad 1 at the top of the outer bottle 5, which is fixed and sealed by a cover 2 with a hole in the middle. After the top of the inner bottle 4 is tied with an iron wire 3, the iron wire 3 passes through the pad 1 and is fixed, hanging in the outer bottle 5.

[0048] In reactor B, there is a pad 1 at the top of the outer bottle 5, which is fixed and sealed by a cover 2 with a hole in the middle. The base 7 is provided with holes and the iron wire 3 passes through, and the iron wire 3 passes through the pad 1 and is fixed, so that the base 7 hangs in the outer bottle 5. The paper 6 is closely attached to the inner wall of the outer bottle 5 and touches the bottom.

[0049] Example 1

[0050] In this example, reactor A is used. Weigh 2.3 mg of Grubbs 1st catalyst and dissolve it in 5 mL of toluene. Use a syringe to take 2 mL of the catalyst solution and add it to the bottom of the outer bottle 5. Place the reactor in an oil bath at 20°C. Purge the reactor with argon for 30 minutes until the solvent completely evaporates. Mix 50 mL of distilled and purified cyclopentene with 50 mg of 9-BBN, stir in a sealed glass bottle for 12 hours, then place the glass bottle in an oil bath at 20°C for 30 minutes. Use a syringe to take 2 mL and add it to the bottom of the inner bottle 4. React the reactor in an oil bath at 20°C for 6 hours. The polymer properties and yields are shown in Table 1.

[0051] Example 2

[0052] Reactor A was used in this example. 2.3 mg of Grubbs 1st catalyst was weighed and dissolved in 50 mL of toluene. 2 mL of the catalyst solution was taken with a syringe and added to the bottom of the outer flask 5. The reactor was placed in an oil bath at 20 °C. The reactor was purged with argon for 30 minutes until the solvent completely evaporated. 50 mL of distilled and purified cyclopentene was mixed with 50 mg of 9-BBN. After stirring in a sealed glass bottle for 12 hours, the glass bottle was placed in an oil bath at 20 °C for 30 minutes. 2 mL was taken with a syringe and added to the bottom of the inner flask 4. The reactor was reacted in the oil bath at 20 °C for 6 hours. The polymer properties and yields are shown in Table 1.

[0053] Example 3

[0054] Reactor A was used in this example. 0.92 mg of Grubbs 1st catalyst was weighed and dissolved in 200 mL of toluene. 2 mL of the catalyst solution was taken with a syringe and added to the bottom of the outer flask 5. The reactor was placed in an oil bath at 20 °C. The reactor was purged with argon for 30 minutes until the solvent completely evaporated. 50 mL of distilled and purified cyclopentene was mixed with 50 mg of 9-BBN. After stirring in a sealed glass bottle for 12 hours, the glass bottle was placed in an oil bath at 20 °C for 30 minutes. 2 mL was taken with a syringe and added to the bottom of the inner flask 4. The reactor was reacted in the oil bath at 20 °C for 6 hours. The polymer properties and yields are shown in Table 1.

[0055] Example 4

[0056] Reactor A was used in this example. 2.3 mg of Grubbs 1st catalyst was weighed and dissolved in 5 mL of toluene. 2 mL of the catalyst solution was taken with a syringe and added to the bottom of the outer flask 5. The reactor was placed in an oil bath at 30 °C. The reactor was purged with argon for 30 minutes until the solvent completely evaporated. 50 mL of distilled and purified cyclopentene was mixed with 50 mg of 9-BBN. After stirring in a sealed glass bottle for 12 hours, the glass bottle was placed in an oil bath at 30 °C for 30 minutes. 2 mL was taken with a syringe and added to the bottom of the inner flask 4. The reactor was reacted in the oil bath at 30 °C for 6 hours. The polymer properties and yields are shown in Table 1.

[0057] Example 5

[0058] In this example, reactor A was used. 2.3 mg of Grubbs 1st catalyst was weighed and dissolved in 50 mL of toluene. 2 mL of the catalyst solution was taken with a syringe and added to the bottom of the outer flask 5. The reactor was placed in an oil bath at 30 °C. The reactor was purged with argon for 30 minutes until the solvent completely evaporated. 50 mL of distilled and purified cyclopentene was mixed with 50 mg of 9-BBN. After stirring in a sealed glass bottle for 12 hours, the glass bottle was placed in an oil bath at 30 °C for 30 minutes. 2 mL was taken with a syringe and added to the bottom of the inner flask 4. The reactor was reacted in an oil bath at 30 °C for 6 hours. The polymer properties and yields are shown in Table 1.

[0059] Example 6

[0060] In this example, reactor A was used. 0.92 mg of Grubbs 1st catalyst was weighed and dissolved in 200 mL of toluene. 2 mL of the catalyst solution was taken with a syringe and added to the bottom of the outer flask 5. The reactor was placed in an oil bath at 30 °C. The reactor was purged with argon for 30 minutes until the solvent completely evaporated. 50 mL of distilled and purified cyclopentene was mixed with 50 mg of 9-BBN. After stirring in a sealed glass bottle for 12 hours, the glass bottle was placed in an oil bath at 30 °C for 30 minutes. 2 mL was taken with a syringe and added to the bottom of the inner flask 4. The reactor was reacted in an oil bath at 30 °C for 6 hours. The polymer properties and yields are shown in Table 1.

[0061] Example 7

[0062] In this example, reactor A was used. 2.3 mg of Grubbs 1st catalyst was weighed and dissolved in 5 mL of toluene. 2 mL of the catalyst solution was taken with a syringe and added to the bottom of the outer flask 5. The reactor was placed in an ice-water bath at 0 °C. The reactor was purged with argon for 30 minutes until the solvent completely evaporated. 50 mL of distilled and purified cyclopentene was mixed with 50 mg of 9-BBN. After stirring in a sealed glass bottle for 12 hours, the glass bottle was placed in an ice-water bath at 0 °C for 30 minutes. 2 mL was taken with a syringe and added to the bottom of the inner flask 4. The reactor was reacted in an ice-water bath at 0 °C for 6 hours.

[0063] Example 8

[0064] In this example, reactor A was used. 2.3 mg of Grubbs 1st catalyst was weighed and dissolved in 50 mL of toluene. 2 mL of the catalyst solution was taken with a syringe and added to the bottom of the outer flask 5. The reactor was placed in an ice-water bath at 0 °C. The reactor was purged with argon for 30 minutes until the solvent completely evaporated. 50 mL of distilled and purified cyclopentene was mixed with 50 mg of 9-BBN. After stirring in a sealed glass bottle for 12 hours, the glass bottle was placed in an ice-water bath at 0 °C for 30 minutes. 2 mL was taken with a syringe and added to the bottom of the inner flask 4. The reactor was reacted in an ice-water bath at 0 °C for 6 hours. The polymer properties and yields are shown in Table 1.

[0065] Example 9

[0066] Reactor A was used in this example. 0.92 mg of Grubbs 1st catalyst was weighed and dissolved in 200 mL of toluene. 2 mL of the catalyst solution was taken with a syringe and added to the bottom of the outer flask 5. The reactor was placed in an ice-water bath at 0 °C. The reactor was purged with argon for 30 minutes until the solvent was completely volatilized. 50 mL of distilled and purified cyclopentene was mixed with 50 mg of 9-BBN. After stirring in a sealed glass bottle for 12 hours, the glass bottle was placed in an ice-water bath at 0 °C for 30 minutes. 2 mL was taken with a syringe and added to the bottom of the inner flask 4. The reactor was reacted in an ice-water bath at 0 °C for 6 hours. The polymer properties and yields are shown in Table 1.

[0067] Example 10

[0068] Reactor A was used in this example. 2.4 mg of Grubbs 2nd was weighed and dissolved in 5 mL of toluene. 2 mL of the catalyst solution was taken with a syringe and added to the bottom of the outer flask 5. The reactor was placed in an oil bath at 20 °C. The reactor was purged with argon for 30 minutes until the solvent was completely volatilized. 50 mL of distilled and purified cyclopentene was mixed with 50 mg of 9-BBN. After stirring in a sealed glass bottle for 12 hours, the glass bottle was placed in an oil bath at 20 °C for 30 minutes. 2 mL was taken with a syringe and added to the bottom of the inner flask 4. The reactor was reacted in an oil bath at 20 °C for 6 hours. The polymer properties and yields are shown in Table 1.

[0069] Example 11

[0070] Reactor A was used in this example. 2.4 mg of Grubbs 2nd was weighed and dissolved in 50 mL of toluene. 2 mL of the catalyst solution was taken with a syringe and added to the bottom of the outer flask 5. The reactor was placed in an oil bath at 20 °C. The reactor was purged with argon for 30 minutes until the solvent was completely volatilized. 50 mL of distilled and purified cyclopentene was mixed with 50 mg of 9-BBN. After stirring in a sealed glass bottle for 12 hours, the glass bottle was placed in an oil bath at 20 °C for 30 minutes. 2 mL was taken with a syringe and added to the bottom of the inner flask 4. The reactor was reacted in an oil bath at 20 °C for 6 hours. The polymer properties and yields are shown in Table 1.

[0071] Example 12

[0072] Reactor A was used in this example. 2.3 mg of Grubbs 1st catalyst was weighed and dissolved in 5 mL of toluene. 2 mL of the catalyst solution was taken with a syringe and added to the bottom of the outer flask 5. The reactor was placed in an oil bath at 30 °C. The reactor was purged with argon for 30 minutes until the solvent completely evaporated. 50 mL of cycloheptene purified by distillation was mixed with 50 mg of 9-BBN. After stirring in a sealed glass bottle for 12 hours, the glass bottle was placed in an oil bath at 30 °C for 30 minutes. 2.6 mL was taken with a syringe and added to the bottom of the inner flask 4. The reactor was reacted in an oil bath at 30 °C for 6 hours. The polymer properties and yields are shown in Table 1.

[0073] Example 13

[0074] Reactor B was used in this example. 2.3 mg of Grubbs 1st catalyst was weighed and dissolved in 5 mL of toluene. 2 mL of the catalyst solution was taken with a syringe and added to a glass dish. Paper 6 was immersed in the catalyst solution so that all the solution was infiltrated in Paper 6. The material of Paper 6 was filter paper. After purging the filter paper with argon for 30 minutes until the solvent completely evaporated, Paper 6 was fixed on the silica gel pad 1 with wire 3 and suspended in the outer flask 5. 50 mL of cycloheptene purified by distillation was mixed with 50 mg of 9-BBN. After stirring in a sealed glass bottle for 12 hours, the glass bottle was placed in an oil bath at 30 °C for 30 minutes. 2.6 mL was taken with a syringe and added to the bottom of the outer flask 5. The reactor was reacted in an oil bath at 30 °C for 6 hours. The polymer properties and yields are shown in Table 1.

[0075] Example 14

[0076] Reactor A was used in this example. 2.3 mg of Grubbs 1st catalyst was weighed and dissolved in 5 mL of toluene. 2 mL of the catalyst solution was taken with a syringe and added to the bottom of the outer flask 5. The reactor was placed in an oil bath at 20 °C. The reactor was purged with argon for 30 minutes until the solvent completely evaporated. 50 mL of cyclopentene that was not purified by distillation was placed in an oil bath at 20 °C for 30 minutes. 2 mL was taken with a syringe and added to the bottom of the inner flask 5. The reactor was reacted in an oil bath at 20 °C for 6 hours. The polymer properties and yields are shown in Table 1.

[0077] Comparative Example 1

[0078] In this comparative example, reactor A was used. 2.3 mg of Grubbs 1st catalyst was weighed and dissolved in 5 mL of toluene. 2 mL of the catalyst solution was taken with a syringe and added to the bottom of outer flask 5. The reactor was placed in an oil bath at 20 °C. The reactor was purged with argon for 30 minutes until the solvent completely evaporated. 50 mL of distilled and purified cyclopentene was mixed with 50 mg of 9-BBN. After stirring in a sealed glass bottle for 12 hours, the glass bottle was placed in an oil bath at 20 °C for 30 minutes. 2 mL was taken with a syringe and added to the bottom of outer flask 5. The reactor was reacted in the oil bath at 20 °C for 6 hours. The polymer properties and yields are shown in Table 1.

[0079] Comparative Example 2

[0080] In this comparative example, reactor A was used. 2.3 mg of Grubbs 1st catalyst was weighed and dissolved in 50 mL of toluene. 2 mL of the catalyst solution was taken with a syringe and added to the bottom of outer flask 5. The reactor was placed in an oil bath at 20 °C. The reactor was purged with argon for 30 minutes until the solvent completely evaporated. 50 mL of distilled and purified cyclopentene was mixed with 50 mg of 9-BBN. After stirring in a sealed glass bottle for 12 hours, the glass bottle was placed in an oil bath at 20 °C for 30 minutes. 2 mL was taken with a syringe and added to the bottom of outer flask 5. The reactor was reacted in the oil bath at 20 °C for 6 hours. The polymer properties and yields are shown in Table 1.

[0081] Comparative Example 3

[0082] In this comparative example, reactor A was used. 0.92 mg of Grubbs 1st catalyst was weighed and dissolved in 200 mL of toluene. 2 mL of the catalyst solution was taken with a syringe and added to the bottom of outer flask 5. The reactor was placed in an oil bath at 20 °C. The reactor was purged with argon for 30 minutes until the solvent completely evaporated. 50 mL of distilled and purified cyclopentene was mixed with 50 mg of 9-BBN. After stirring in a sealed glass bottle for 12 hours, the glass bottle was placed in an oil bath at 20 °C for 30 minutes. 2 mL was taken with a syringe and added to the bottom of outer flask 5. The reactor was reacted in the oil bath at 20 °C for 6 hours. The polymer properties and yields are shown in Table 1.

[0083] It can be seen from the results of the examples and comparative examples that the polymer obtained by gas-solid polymerization has a higher molecular weight than that obtained by solution polymerization. As the reaction temperature decreases, the molecular weight of the polymer further increases. Due to the limitations of the analytical instrument, we can only measure the polymer samples that can be dissolved at room temperature. In some cases, the polymer is partially insoluble at room temperature. Therefore, we speculate that the actual molecular weight of the polymer is higher than the measured result.

[0084] Synthesis Example 1

[0085] 1 g of the polymer obtained in Example 7 was added to a 100 mL round-bottom flask, and 5 mg of 2,6-di-tert-butyl-4-methylphenol and 70 mL of xylene were added. After heating under reflux at 140 °C until the polymer was dissolved, 12.5 mL of tributylamine and 9 g of p-toluenesulfonylhydrazide were added, and stirring was continued for 12 hours. The hot solution was poured into 500 mL of cold methanol for precipitation, and the obtained solid was dried in vacuo to obtain 1.03 g of a white solid. As Figure 3 shown, using solid-state nuclear magnetic resonance carbon spectrum CP / MAS 13 13C NMR measurement showed that the obtained product only showed a peak at 35 ppm and no peaks in the range of 100 to 150 ppm. Therefore, the double bonds in the raw material were completely hydrogenated, and the obtained product was unbranched polyethylene.

[0086] Table 1

[0087]

[0088]

[0089] It can be seen from the content of Table 1 that the technical solution of the present invention can obtain polyolefin products with ultra-high molecular weight and narrow molecular weight distribution.

Claims

1. A method for preparing polyolefin, characterized in that, Using a cycloolefin monomer as a gas phase and loading the catalyst on a substrate material, wherein the catalyst is in a solid phase; Subjecting the cycloolefin monomer to a gas-solid polymerization reaction under the action of the catalyst to obtain the polyolefin; The loading amount of the catalyst on the substrate material is 0.5 to 1000 ppm.

2. The preparation method according to claim 1, characterized in that, The method for loading the catalyst includes: Preparing the catalyst into a catalyst solution with an organic solvent, distributing the catalyst solution on the substrate material, and then removing the organic solvent.

3. The preparation method according to claim 2, characterized in that, The organic solvent is one or a combination of two or more of linear aliphatic hydrocarbons, cyclic aliphatic hydrocarbons, and aromatic hydrocarbons.

4. The preparation method according to claim 2, wherein The concentration of the catalyst solution is 1 to 2000 μmol / L.

5. The preparation method according to claim 1, characterized in that, The catalyst includes one or a combination of two or more of ruthenium ROMP catalysts, tungsten ROMP catalysts, molybdenum ROMP catalysts, and rhenium ROMP catalysts.

6. The preparation method according to claim 1, wherein The substrate material includes one of glass, silicon wafers, paper, aluminum foil, stainless steel, and plastics; Preferably, the substrate material is placed at the bottom of the reactor.

7. The preparation method according to claim 1, characterized in that, The reaction temperature of the gas-solid polymerization reaction is -80 to 200 °C, and the reaction time is 30 min to 12 h.

8. The preparation method according to claim 1, characterized in that, The cycloolefin monomer includes one or a combination of two or more of the cycloolefins shown in Formula 1, Formula 2, Formula 3, Formula 4, and Formula 5; wherein, n = 1, 3, 4, or 8.

9. The preparation method according to claim 2, characterized in that, The method for removing the organic solvent includes: drying the organic solvent with an inert gas; Preferably, the temperature of the inert gas is 0 to 50 °C.

10. The preparation method according to claim 1, wherein, Before the gas-solid polymerization reaction, the preparation method further includes a purification treatment of the cycloolefin monomer; preferably, the purification treatment of the cycloolefin monomer includes distillation and / or hydroboration.

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