A method for preparing cyclic polyolefins

Abstract

This invention provides a method for preparing cyclic polyolefins, belonging to the technical field of preparing cyclic olefin polymers. The method includes: initiating ring-opening metathesis polymerization of cyclic olefin monomers using a catalyst; adding a polar monomer to obtain a mixture of linear block polymers and cyclic polymers; adding a quencher to quench the reaction; and separating to obtain the cyclic polyolefin; wherein the cyclic olefin monomer is selected as C. 5~20 The invention relates to an olefin containing carbon-carbon double bonds; the linear block polymer has polar blocks. By adding a polar monomer with a special structure after the ring-opening metathesis polymerization of a cyclic olefin, the two products can be easily separated in post-processing, yielding the target cyclic polyolefin.

Description

Technical Field

[0001] This invention relates to the technical field of preparing cyclic olefin polymers, and more specifically to a method for preparing cyclic polyolefins. Background Technology

[0002] The application of lubricating materials is limited by their high replacement costs. One improvement measure is to extend the service life of lubricants. To date, the most common lubricant is polyalphaolefin (PAO), whose viscosity gradually decreases during use due to continuous chain breakage. Cyclic hydrocarbon polymers, similar to PAO, possess unique tribological properties. After the first chain breakage of a cyclic hydrocarbon polymer, it generates a linear polymer with a larger chain volume, and its viscosity increases. This unique property makes it a potential additive to modify viscosity and improve the service life of lubricants.

[0003] Cyclic polymers composed of pure hydrocarbons can currently only be obtained by ring-opening metathesis polymerization of cyclic olefin monomers. The linear and cyclic products are difficult to separate due to their similar chemical properties. A thermodynamic equilibrium exists between cyclic and linear polymers during polymerization. When polymerization is carried out in solution, a polymer with a completely cyclic configuration can only be obtained when the monomer concentration is below a certain value. In actual production, this results in insufficient production efficiency, and the weight-average molecular weight of the obtained products does not meet production requirements. For example, for cyclooctene monomers, this concentration is 0.1 mol / L (J. Am. Chem. Soc. 2013, 135(15), 5717–5725; Org. Lett. 2010, 12 (17), 3729–3731; J. Am. Chem. Soc. 2007,129 (5), 1105–1112; Chem. Sci. 2011, 2 (3), 429–438). When the monomer concentration is 0.1 mol / L, the production efficiency is low, and the weight-average molecular weight of the product is only 1600 g / mol. When the monomer concentration is higher than this value, only a mixture of cyclic and linear polymers can be obtained.

[0004] Therefore, those skilled in the art urgently need a method that can easily generate and separate cyclic polymers under conventional reaction conditions, and can increase the molecular weight of the product. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing cyclic polyolefins to solve the problem of difficulty in separating linear and cyclic products generated by conventional ring-opening metathesis polymerization reactions.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0007] This invention provides a method for preparing cyclic polyolefins, comprising the following steps: initiating ring-opening metathesis polymerization of cyclic olefin monomers using a catalyst; adding a polar monomer to obtain a mixture of linear block polymers and cyclic polymers; adding a quencher to quench the reaction; and separating to obtain cyclic polyolefins.

[0008] The cyclic olefin monomer is selected as C. 5~20 Alkenes containing carbon-carbon double bonds;

[0009] The linear block polymer has polar blocks;

[0010] The structure of the polar monomer is shown in Formula I:

[0011]

[0012] Formula I

[0013] In Equation I, m is 0 or 1;

[0014] R5 and R6 are independently selected from hydrogen, substituted or unsubstituted hydrocarbon groups; at least one of the substituents in R5 and R6 contains a polar functional group.

[0015] The method for preparing cyclic polyolefins as described above, wherein the polar functional groups include: oxygen-containing polar functional groups, nitrogen-containing functional groups, halogen-containing functional groups, and silicon-containing functional groups.

[0016] In the preparation method of cyclic polyolefins as described above, the molar ratio of the polar monomer to the cyclic olefin monomer is (0.01~10):1.

[0017] In the method for preparing cyclic polyolefins as described above, the cyclic olefin monomer is selected from one or more of cyclopentene, cyclopentadiene, cycloheptene, cyclooctene, cyclooctadiene, and dodecathoriene.

[0018] In the method for preparing cyclic polyolefins as described above, the ring-opening metathesis polymerization is carried out in an organic solvent, and the concentration of the cyclic olefin monomer is 0.1~50 mol / L.

[0019] In the method for preparing cyclic polyolefins as described above, the molar ratio of the catalyst to the cyclic olefin monomer is 1:(10~1×10). 6 ).

[0020] In the method for preparing cyclic polyolefins as described above, the catalyst is selected from one or more of Grubbs Generation I, Grubbs Generation II, Grubbs Generation III, Hoveyda-Grubbs Generation I, and Hoveyda-Grubbs Generation II.

[0021] In the method for preparing cyclic polyolefins as described above, the ring-opening metathesis polymerization reaction time is 1~6×10⁻⁶. 3 min.

[0022] In the method for preparing cyclic polyolefins as described above, the ring-opening metathesis polymerization reaction temperature is -50~200℃.

[0023] The method for preparing cyclic polyolefins as described above, wherein the method for separating the cyclic polyolefins includes column chromatography separation and sedimentation separation.

[0024] Compared with the prior art, the advantages of the present invention are as follows:

[0025] This invention adds a polar monomer with a special structure after the ring-opening metathesis polymerization of cyclic olefins, thereby increasing the second polar block in the linear polyolefin. This results in a difference in chemical properties between the linear and cyclic polyolefins, making it easier to separate the two products in post-processing to obtain the target cyclic polyolefin. Furthermore, this invention optimizes the reaction conditions, enabling the production of cyclic polyolefins with higher molecular weights. Attached Figure Description

[0026] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0027] Figure 1 The polar monomer used in the embodiments of the present invention 1 H-NMR spectrum;

[0028] Figure 2 As in Embodiment 1 of the present invention 1 H-NMR spectrum;

[0029] Figure 3 As in Embodiment 12 of the present invention 1 H-NMR spectrum;

[0030] Figure 4 As in Embodiment 19 of the present invention 1 H-NMR spectrum;

[0031] Figure 5 As Comparative Example 1 of the present invention 1 H-NMR spectrum. Detailed Implementation

[0032] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below. The specific embodiments listed below are merely descriptions of the principles and features of the present invention, and the examples are only for explaining the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] On one hand, the present invention provides a method for preparing cyclic polyolefins, comprising the following steps: initiating ring-opening metathesis polymerization of cyclic olefin monomers using a catalyst; adding a polar monomer to obtain a mixture of linear block polymers and cyclic polymers; adding a quencher to quench the reaction; and separating to obtain cyclic polyolefins.

[0034] Among them, the cyclic olefin monomer is selected as C. 5~20 Alkenes containing carbon-carbon double bonds;

[0035] Linear block polymers have polar blocks;

[0036] The structure of the polar monomer is shown in Formula I:

[0037]

[0038] Formula I

[0039] In the formula, m is 0 or 1;

[0040] R5 and R6 are independently selected from hydrogen, substituted or unsubstituted hydrocarbon groups; at least one of the substituents in R5 and R6 contains a polar functional group.

[0041] The linear and cyclic products generated by conventional ring-opening metathesis polymerization are difficult to separate due to their similar chemical properties. Introducing a difference in chemical properties between the two products makes separation easier. This invention adds a polar monomer with a special structure after the ring-opening metathesis polymerization of cyclic olefins, adding a second polar block to the linear polyolefin. This creates a chemical difference between the linear and cyclic polyolefins, facilitating separation of the two products during post-processing to obtain the target cyclic polyolefin.

[0042] Specifically, polar functional groups include: oxygen-containing polar functional groups, nitrogen-containing functional groups, halogen-containing functional groups, and silicon-containing functional groups.

[0043] Ring-opening metathesis polymerization, a type of living polymerization, is an effective method for synthesizing block polymers. After the monomer polymerization of the target product is complete, adding a polar monomer adds a second polar block to the linear polymer. In contrast, cyclic polyolefins lack connected catalytic active centers, so the added polar monomer will not polymerize into the cyclic polyolefin. This creates a chemical difference between linear and cyclic polyolefins, allowing the cyclic polyolefin to be separated using conventional separation methods.

[0044] Specifically, the polar functional groups are selected as carboxyl, sulfonic acid, phosphoric acid, hydroxyl, cyano, primary amine, secondary amine, amide, fluorine, chlorine, bromine, trifluoromethyl, pentafluoroethyl, trimethoxysilane, triethoxysilane, and methyldiethoxysilane.

[0045] According to another embodiment of the present invention, a process is described in which a catalyst is used to initiate the ring-opening metathesis polymerization of cyclic olefin monomers; a polar monomer is added to obtain a mixture of linear block polymers and cyclic polymers, and the reaction formula is as follows:

[0046]

[0047] This invention utilizes a polar monomer with the aforementioned special structure. Because its backbone is a norbornene structure containing a bridged ring, it exhibits high ring strain and therefore demonstrates high reactivity in ring-opening metathesis polymerization, with a polymerization rate much faster than that of monocyclic olefin monomers without a bridged ring. Upon addition, it rapidly polymerizes and undergoes quenching without affecting the reaction equilibrium prior to addition. Furthermore, the polar monomer with the norbornene structure can be obtained via Diels-Alder addition, making its synthesis simple, easy to modify, and allowing for the addition of various desired polar functional groups.

[0048] Specifically, the molar ratio of polar monomers to cyclic olefin monomers is (0.01~10):1.

[0049] Specifically, the molar ratio of polar monomers to cyclic olefin monomers is (0.05~1):1.

[0050] The amount of polar monomer added is based on a polarity difference sufficient to separate the linear and cyclic polymers. Adding more than this amount results in wasted polar monomers; adding less than this amount, the increased polarity in the linear polymer is insufficient to completely separate it from the cyclic polymer. The ratio used in this patent represents the minimum amount required to completely separate the linear and cyclic polymers.

[0051] There are no special requirements for the solvent used to dissolve the polar monomer, as long as it has good solubility for the polar monomer and is miscible with the solvent used in the polymerization initiation stage. Examples include tetrahydrofuran, dichloromethane, tetrachloroethane, N,N-dimethylformamide, acetonitrile, and dimethyl sulfoxide. The amount of solvent added should be sufficient to completely dissolve the required amount of polar monomer.

[0052] Specifically, the cyclic olefin monomer is selected from one or more of cyclopentene, cyclopentadiene, cycloheptene, cyclooctene, cyclooctadiene, and dodecathoriene.

[0053] Specifically, the ring-opening metathesis polymerization is carried out in an organic solvent.

[0054] The polymerization steps described above can also be carried out in a solvent-free system. However, it is easier to control the reaction when carried out in an organic solvent.

[0055] Specifically, organic solvents can disperse or dissolve the resulting polymers.

[0056] Specifically, the organic solvent is selected from aliphatic hydrocarbons, aromatic hydrocarbons, halogenated aliphatic hydrocarbons, halogenated aromatic hydrocarbons, nitrogen-containing solvents, ethers, and aromatic ethers.

[0057] Specifically, the organic solvent is selected from aromatic hydrocarbons, ethers, and aromatic ethers.

[0058] Specifically, the organic solvent is selected from cyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, ethylcyclohexane, diethylcyclohexane, decahydronaphthalene, bicyclohepten, tricyclodecane, hexahydroindene, cyclooctane, benzene, toluene, xylene, dichloromethane, chloroform, 1,2-dichloroethane, chlorobenzene, dichlorobenzene, nitromethane, nitrobenzene, acetonitrile, diethyl ether, tetrahydrofuran, such as anisole and phenethyl ether.

[0059] Specifically, the concentration of cyclic olefin monomers is 0.1~50 mol / L.

[0060] Specifically, the concentration of cyclic olefin monomers is 1~40 mol / L.

[0061] When the monomer concentration is too low, production efficiency will decrease. When the monomer concentration is too high, the viscosity of the reaction solution after polymerization will be too high, making subsequent processing difficult.

[0062] Specifically, the molar ratio of catalyst to cyclic olefin monomer is 1:(10~1×10). 6 ).

[0063] Specifically, the molar ratio of catalyst to cyclic olefin monomer is 1:(200~5×10⁻⁶). 5 ).

[0064] Specifically, the molar ratio of catalyst to cyclic olefin monomer is 1:(500~1×10⁻⁶). 5 ).

[0065] If the amount of catalyst is too high, catalyst removal becomes difficult. If the amount of catalyst is too low, effective polymerization activity is difficult to achieve.

[0066] Specifically, the catalyst is selected from one or more of the following: Grubbs Generation 1, Grubbs Generation 2, Grubbs Generation 3, Hoveyda-Grubbs Generation 1, and Hoveyda-Grubbs Generation 2.

[0067] Specifically, the reaction time for ring-opening metathesis polymerization is 1~6×10⁻⁶. 3 min.

[0068] Specifically, the reaction time for ring-opening metathesis polymerization ranges from 1 to 400 minutes. For some monomers, extending the reaction time alters the reaction equilibrium, leading to an increase in the yield of the cyclic polymer product and a decrease in its molecular weight. Excessively long reaction times can cause catalyst decomposition and deactivation, resulting in the presence of linear polymer impurities in the separated cyclic polymer.

[0069] Specifically, the ring-opening metathesis polymerization reaction temperature is -50~200℃.

[0070] Specifically, the ring-opening metathesis polymerization reaction temperature is -30~150℃.

[0071] Specifically, the ring-opening metathesis polymerization reaction temperature is 0~60℃.

[0072] Higher reaction temperatures can shift the reaction equilibrium toward cyclic polymers; however, excessively high reaction temperatures can deactivate the catalyst, resulting in linear polymer impurities.

[0073] Specifically, the structure of the quencher is shown in Formula II:

[0074]

[0075] Formula II

[0076] In the formula, R1 is chosen as hydrogen, and C 1~20 Alkyl, C 1~20 cycloalkyl, C 2~20 alkenyl, C 6~20 Aryl or heterocyclic; R2 is chosen as C 1~20 Alkyl, C 1~20 Cycloalkyl, aryl, or heterocyclic.

[0077] Specifically, R1 is selected as C. 1~20 Alkyl groups can be substituted with aromatic groups.

[0078] The amount of quencher added depends on the amount of catalyst added, and is generally between 1 and 10 times the molar amount of catalyst.

[0079] Specifically, the methods for separating cyclic polyolefins include column chromatography and sedimentation separation.

[0080] Specifically, when using column chromatography for separation, the stationary phase is silica gel or alumina, and the mobile phase is one or more of the following: straight-chain aliphatic hydrocarbons, cyclic aliphatic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, and tetrahydrofuran.

[0081] Specifically, when using sedimentation separation, the good solvent and the bad solvent are selected from one or more of straight-chain aliphatic hydrocarbons, cyclic aliphatic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, and tetrahydrofuran.

[0082] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0083] A polar monomer used in the embodiments of the present invention is prepared by the following method:

[0084]

[0085] 10 g of cis-5-norbornene-exo-2,3-dicarboxylic anhydride was added to 50 mL of 2 mol / L sodium hydroxide aqueous solution and heated to 80 °C with stirring for 6 h until the solid was completely dissolved. The solution was cooled to 0 °C, and the pH was adjusted to 1 using hydrochloric acid. The reaction solution was extracted twice with 100 mL of ethyl acetate, and the resulting ethyl acetate solution was dried over sodium sulfate. The solution was filtered to remove the solvent, yielding 11 g of norbornene dicarboxylic acid as a white solid. 1 H-NMR spectrum as shown Figure 1 As shown.

[0086] Example 1

[0087] This embodiment provides a method for preparing cyclic polyolefins, including:

[0088] 1) In an argon-protected atmosphere at 20°C, 19 mg of Grubbs third-generation catalyst, 2.7 mL of toluene, and 300 mg of 1,5-cyclooctadiene were mixed to allow the Grubbs third-generation catalyst to initiate the ring-opening metathesis polymerization of 1,5-cyclooctadiene.

[0089] 2) After 30 minutes, add 50 mg of norbornene dicarboxylic acid dissolved in 1 mL of tetrahydrofuran;

[0090] 3) After 1 minute, add 100 μL of vinyl ether. Add 2 g of silica gel to the reaction solution, evaporate to remove toluene, add the silica gel to a glass column containing 10 g of silica gel, wash the silica gel column with an eluent prepared from 100 mL of hexane and 30 mL of dichloromethane, collect the eluent, evaporate to remove the solvent, and obtain cyclic polycyclooctadiene. 1 H-NMR spectrum as shown Figure 2 As shown.

[0091] Example 2

[0092] This embodiment provides a method for preparing cyclic polyolefins, including:

[0093] In an argon-protected atmosphere at 20°C, 19 mg of Grubbs third-generation catalyst, 2.7 mL of toluene, and 300 mg of 1,5-cyclooctadiene were mixed to allow the Grubbs third-generation catalyst to initiate the ring-opening metathesis polymerization of 1,5-cyclooctadiene.

[0094] After 30 minutes, add 50 mg of norbornene dicarboxylic acid dissolved in 1 mL of tetrahydrofuran;

[0095] After 1 minute, add 100 μL of vinyl ether. Prepare a solution in a beaker by mixing 100 mL of hexane and 10 mL of dichloromethane. Pour the polymer solution obtained from the polymerization reaction into the beaker. Filter to remove the solid, collect the resulting liquid, and remove the solvent to obtain cyclic polycyclooctadiene.

[0096] Example 3

[0097] This embodiment is basically the same as embodiment 2, except that...

[0098] In step 1), the temperature for ring-opening metathesis polymerization is adjusted to 0°C; other conditions remain unchanged.

[0099] Example 4

[0100] This embodiment is basically the same as embodiment 2, except that...

[0101] In step 1), the temperature for ring-opening metathesis polymerization is adjusted to 50°C; other conditions remain unchanged.

[0102] Example 5

[0103] This embodiment is basically the same as embodiment 2, except that...

[0104] Step 1) is adjusted to "In an argon protective atmosphere, at 20°C, mix 19 mg of Grubbs third-generation catalyst, 10 mL of toluene, and 300 mg of 1,5-cyclooctadiene to allow the Grubbs third-generation catalyst to initiate the ring-opening metathesis polymerization of 1,5-cyclooctadiene"; other conditions remain unchanged.

[0105] Example 6

[0106] This embodiment is basically the same as embodiment 2, except that...

[0107] Step 1) is adjusted to "In an argon protective atmosphere at 20°C, mix 19 mg of Grubbs third-generation catalyst, 27 mL of toluene, and 300 mg of 1,5-cyclooctadiene to allow the Grubbs third-generation catalyst to initiate the ring-opening metathesis polymerization of 1,5-cyclooctadiene"; other conditions remain unchanged.

[0108] Example 7

[0109] This embodiment is basically the same as embodiment 2, except that...

[0110] Step 2) is adjusted to "After 5 minutes, add 50 mg of norbornene dicarboxylic acid dissolved in 1 mL of tetrahydrofuran", that is, the ring-opening metathesis polymerization time in step 1) is adjusted to 5 minutes; other conditions remain unchanged.

[0111] Example 8

[0112] This embodiment is basically the same as embodiment 2, except that...

[0113] In step 1), the mass of the Grubbs third-generation catalyst was adjusted to 5 mg; other conditions remained unchanged.

[0114] Example 9

[0115] This embodiment is basically the same as embodiment 2, except that...

[0116] In step 1), the mass of the Grubbs third-generation catalyst was adjusted to 2 mg; other conditions remained unchanged.

[0117] Example 10

[0118] This embodiment is basically the same as embodiment 2, except that...

[0119] In step 1), the 19 mg Grubbs third-generation catalyst in Example 2 was replaced with 16 mg Hoveyda-Grubbs second-generation catalyst; other conditions remained unchanged.

[0120] Example 11

[0121] This embodiment is basically the same as embodiment 9, except that...

[0122] In step 1), adjust the volume of toluene to 10 ml; keep other conditions unchanged.

[0123] Example 12

[0124] This embodiment is basically the same as embodiment 2, except that...

[0125] In step 1), 305 mg of cyclooctene was used instead of 300 mg of 1,5-cyclooctadiene in Example 2; other conditions remained unchanged.

[0126] The cyclic polycyclooctene obtained in Example 12 1 H-NMR spectrum as shown Figure 3 As shown.

[0127] Example 13

[0128] This embodiment is basically the same as embodiment 12, except that...

[0129] In step 1), the mass of the Grubbs third-generation catalyst was adjusted to 2 mg; other conditions remained unchanged.

[0130] Example 14

[0131] This embodiment is basically the same as embodiment 12, except that...

[0132] In step 1), the temperature of the ring-opening metathesis polymerization was adjusted to 50°C; other conditions remained unchanged.

[0133] Example 15

[0134] This embodiment is basically the same as embodiment 12, except that...

[0135] In step 1), adjust the volume of toluene to 10 ml; keep other conditions unchanged.

[0136] Example 16

[0137] This embodiment is basically the same as embodiment 12, except that...

[0138] In step 1), the volume of toluene was adjusted to 27 ml; other conditions remained unchanged.

[0139] Example 17

[0140] This embodiment is basically the same as embodiment 12, except that...

[0141] Step 2) is adjusted to "After 5 minutes, add 50 mg of norbornene dicarboxylic acid dissolved in 1 mL of tetrahydrofuran", that is, the ring-opening metathesis polymerization time in step 1) is adjusted to 5 minutes; other conditions remain unchanged.

[0142] Example 18

[0143] This embodiment is basically the same as embodiment 16, except that...

[0144] In step 1), the 19 mg Grubbs third-generation catalyst of Example 16 was replaced with 16 mg Hoveyda-Grubbs second-generation catalyst; other conditions remained unchanged.

[0145] Example 19

[0146] This embodiment is basically the same as embodiment 2, except that...

[0147] In step 1), 190 mg of cyclopentene was used instead of 300 mg of 1,5-cyclooctadiene in Example 2; other conditions remained unchanged.

[0148] The cyclic polycyclopentene obtained in Example 19 1 H-NMR spectrum as shown Figure 4 As shown.

[0149] Example 20

[0150] This embodiment is basically the same as embodiment 19, except that...

[0151] In step 1), adjust the volume of toluene to 1 ml; keep other conditions unchanged.

[0152] Example 21

[0153] This embodiment is basically the same as embodiment 1, except that...

[0154] Step 2) is adjusted to "After 30 minutes, add 120 mg of 5-norbornen-2-ol dissolved in 1 mL of tetrahydrofuran;"; other conditions remain unchanged.

[0155] Example 22

[0156] This embodiment is basically the same as embodiment 1, except that...

[0157] Step 2) is adjusted to "After 30 minutes, add 140 mg of 5-norbornene-2-methanol dissolved in 1 mL of tetrahydrofuran;"; other conditions remain unchanged.

[0158] Example 23

[0159] This embodiment is basically the same as embodiment 1, except that...

[0160] Step 2) is adjusted to "After 30 minutes, add 80 mg of 5-norbornene-2,2-diethanol dissolved in 1 mL of tetrahydrofuran;"; other conditions remain unchanged.

[0161] Example 24

[0162] This embodiment is basically the same as embodiment 1, except that...

[0163] Step 2) is adjusted to "After 30 minutes, add 80 mg of 5-norbornene-2,3-diethanol dissolved in 1 mL of tetrahydrofuran;"; other conditions remain unchanged.

[0164] Example 25

[0165] This embodiment is basically the same as embodiment 1, except that...

[0166] Step 2) is adjusted to "After 30 minutes, add 90 mg of 5-norbornene-2,3-dicarboximide dissolved in 1 mL of tetrahydrofuran;"; other conditions remain unchanged.

[0167] Example 26

[0168] This embodiment is basically the same as embodiment 1, except that...

[0169] Step 2) is adjusted to "After 30 minutes, add 120 mg of N-hydroxy-5-norbornene-2,3-dicarboximide dissolved in 1 mL of tetrahydrofuran;"; other conditions remain unchanged.

[0170] Comparative Example 1

[0171] This comparative example provides a method for preparing cyclic polyolefins, including:

[0172] In an argon-protected atmosphere at 20°C, 19 mg of Grubbs third-generation catalyst, 2.7 mL of toluene, and 300 mg of 1,5-cyclooctadiene were mixed to allow the Grubbs third-generation catalyst to initiate the ring-opening metathesis polymerization of 1,5-cyclooctadiene.

[0173] After 30 minutes, add 100 μL of vinyl ether. Prepare a solution in a beaker by mixing 100 mL of hexane and 10 mL of dichloromethane. Pour the polymer solution obtained from the polymerization reaction into the beaker. Filter to remove the solid, collect the resulting liquid, and remove the solvent to obtain cyclic polycyclooctadiene.

[0174] That is, in Comparative Example 1, no polar monomer was added, and other reaction conditions were the same as in Example 2, resulting in a mixture of chain and cyclic polycyclooctadiene. 1 H-NMR spectrum as shown Figure 5 As shown.

[0175] Comparative Example 2

[0176] This comparative example provides a method for preparing cyclic polyolefins, including:

[0177] In an argon-protected atmosphere at 20°C, 19 mg of Grubbs third-generation catalyst, 2.7 mL of toluene, and 305 mg of cyclooctene were mixed to allow the Grubbs third-generation catalyst to initiate the ring-opening metathesis polymerization of cyclooctene.

[0178] After 30 minutes, add 100 μL of vinyl ether. Prepare a solution in a beaker by mixing 100 mL of hexane and 10 mL of dichloromethane. Pour the polymer solution obtained from the polymerization reaction into the beaker. Filter to remove the solid, collect the resulting liquid, and remove the solvent to obtain cyclic polycyclooctadiene.

[0179] That is, no polar monomer was added in Comparative Example 2, and other reaction conditions were the same as in Example 12, to obtain a mixture of chain and cyclic polycyclooctene.

[0180] Comparative Example 3

[0181] This comparative example provides a method for preparing cyclic polyolefins, including:

[0182] In an argon-protected atmosphere at 20°C, 19 mg of Grubbs third-generation catalyst, 1 mL of toluene, and 190 mg of cyclopentene were mixed to allow the Grubbs third-generation catalyst to initiate the ring-opening metathesis polymerization of cyclopentene.

[0183] After 30 minutes, add 100 μL of vinyl ether. Prepare a solution in a beaker by mixing 100 mL of hexane and 10 mL of dichloromethane. Pour the polymer solution obtained from the polymerization reaction into the beaker. Filter to remove the solid, collect the resulting liquid, and remove the solvent to obtain cyclic polycyclooctadiene.

[0184] That is, no polar monomer was added in Comparative Example 3, and other reaction conditions were the same as in Example 20, to obtain a mixture of cyclic and chain polycyclopentenes.

[0185] Comparative Example 4

[0186] This comparative example provides a method for preparing cyclic polyolefins, including:

[0187] In an argon-protected atmosphere at 20°C, 16 mg of Hoveyda-Grubbs second-generation catalyst, 2.7 mL of toluene, and 300 mg of 1,5-cyclooctadiene were mixed to allow the Hoveyda-Grubbs second-generation catalyst to initiate the ring-opening metathesis polymerization of 1,5-cyclooctadiene.

[0188] After 30 minutes, add 100 μL of vinyl ether. Prepare a solution in a beaker by mixing 100 mL of hexane and 10 mL of dichloromethane. Pour the polymer solution obtained from the polymerization reaction into the beaker. Filter to remove the solid, collect the resulting liquid, and remove the solvent to obtain cyclic polycyclooctadiene.

[0189] That is, no polar monomer was added in Comparative Example 4, and other reaction conditions were the same as in Example 10, to obtain a mixture of cyclic and chain polycyclic octadiene.

[0190] Comparative Example 5

[0191] This comparative example provides a method for preparing cyclic polyolefins, including:

[0192] In an argon-protected atmosphere at 20°C, 16 mg of Hoveyda-Grubbs second-generation catalyst, 27 mL of toluene, and 305 mg of cyclooctene were mixed to allow the Hoveyda-Grubbs second-generation catalyst to initiate the ring-opening metathesis polymerization of cyclooctene.

[0193] After 30 minutes, add 100 μL of vinyl ether. Prepare a solution in a beaker by mixing 100 mL of hexane and 10 mL of dichloromethane. Pour the polymer solution obtained from the polymerization reaction into the beaker. Filter to remove the solid, collect the resulting liquid, and remove the solvent to obtain cyclic polycyclooctadiene.

[0194] That is, Comparative Example 5 was performed without adding polar monomers, and other reaction conditions were the same as in Example 18, resulting in a mixture of cyclic and chain polycyclooctene.

[0195] Test case

[0196] The molecular weight of the products obtained in the examples and comparative examples was determined;

[0197] Number-average molecular weight, weight-average molecular weight, and molecular weight distribution coefficient were measured using a size-exclusion gel electrophoresis system. This instrument consisted of an Agilent 1260 liquid pump, two Agilent PLgel MIXED-B 300×7.5 mm columns connected in series, a Wyatt 18-angle DAWN HELEOS optical dispersion detector, and a Wyatt Optilab rEX differential refractive index detector. Tetrahydrofuran was used as the solvent and mobile phase at a concentration of 1 g / L and a flow rate of 1 mL / min.

[0198] The results are shown in Table 1:

[0199] Table 1

[0200]

[0201] As shown in Table 1, the addition of polar monomers to increase the polar blocks in linear polymers is necessary for the complete separation of cyclic polymers from the product. Without the addition of polar monomers, the separated cyclic polymers will contain intercalated chain polymers.

[0202] A comparison of different reaction conditions in the examples shows that the most significant factor affecting the yield of cyclic polymers is the monomer concentration; the lower the monomer concentration, the higher the proportion of cyclic polymers. Simultaneously, shortening the reaction time and increasing the reaction temperature are beneficial for increasing the molecular weight of the cyclic polymers. Compared to the Grubbs third-generation catalyst, the Hoveyda-Grubbs second-generation catalyst produces polymers with a higher proportion of cyclic polymers. The amount of catalyst added has a minimal impact on the yield and molecular weight.

[0203] In the comparative example without polar monomers, the linear polymer and the cyclic polymer have no polarity difference, so they cannot be separated using the same separation method as in the example, resulting in a mixture.

[0204] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A process for the preparation of a cyclic polyolefin, characterized in that, The method comprises the following steps: using a catalyst to initiate ring-opening metathesis polymerization of a cyclic olefin monomer; adding a polar monomer to obtain a mixture of linear block polymers and cyclic polymers; adding a quenching agent to quench the reaction; and separating to obtain a cyclic polyolefin; The cyclic olefin monomer is selected from C5-20 olefins containing carbon-carbon double bonds; The linear block polymer has a polar block; The structure of the polar monomer is shown in formula I: Formula I In formula I, m is 0 or 1; R5 and R6 are independently selected from hydrogen, substituted or unsubstituted hydrocarbyl; at least one of the substituents of R5 and R6 contains a polar functional group.

2. The method for producing a cyclic polyolefin according to claim 1, characterized by, The polar functional group includes an oxygen-containing polar functional group, a nitrogen-containing functional group, a halogen-containing functional group, and a silicon-containing functional group.

3. The method for producing a cyclic polyolefin according to claim 2, characterized by, The molar ratio of the polar monomer to the cyclic olefin monomer is (0.01-10):

1.

4. The method for producing a cyclic polyolefin according to claim 3, characterized by, The cyclic olefin monomer is selected from one or more of cyclopentene, cyclopentadiene, cycloheptene, cyclooctene, cyclooctadiene, and dodecatriene.

5. The method for producing a cyclic polyolefin according to claim 4, characterized by, The ring-opening metathesis polymerization is carried out in an organic solvent, and the concentration of the cyclic olefin monomer is 0.1-50 mol / L.

6. The method for producing a cyclic polyolefin according to claim 5, characterized by, The molar ratio of the catalyst to the cyclic olefin monomer is 1: (10~1 x 10 6 ).

7. The method for producing a cyclic polyolefin according to claim 6, characterized by, The catalyst is selected from one or more of Grubbs Generation 1, Grubbs Generation 2, Grubbs Generation 3, Hoveyda-Grubbs Generation 1, and Hoveyda-Grubbs Generation 2.

8. The method for producing a cyclic polyolefin according to claim 7, characterized by, The ring-opening metathesis ROMP reaction time is 1 to 6 x 10 3 min.

9. The method for producing a cyclic polyolefin according to claim 8, characterized by, The ring-opening metathesis polymerization reaction temperature is -50-200°C.

10. The method for producing a cyclic polyolefin according to claim 9, characterized by, The method for separating the cyclic polyolefin includes column chromatography separation and sedimentation separation.

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