Cyclic olefin compound as well as preparation method and application thereof

Abstract

The invention relates to the field of organic synthesis, in particular to a cyclic olefin compound as well as a preparation method and application thereof. According to the method, a cyclic alkene compound and cyclopentadiene are taken as raw materials and subjected to a Diels-Alder reaction under the liquid phase condition at the temperature of 100-200 DEG C and the pressure of 1-5 MPa, the molar ratio of the cyclic alkene compound to the cyclopentadiene is controlled to be (1-2): 1, the reaction can be carried out in a tubular reactor, a kettle reactor or a combined reactor in an intermittent, semi-continuous or continuous mode, and a compound II can be supplemented during the reaction so as to guarantee the constant molar ratio of the raw materials. According to the method, a dicyclopentadiene high-temperature cracking step in a traditional process is omitted, the reaction temperature is low, byproducts are few, the utilization rate of raw materials and the green environmental protection property of a device are improved, and energy consumption and danger are reduced. The cyclic olefin compound prepared by the method is used for ring-opening metathesis polymerization, and the hydrogenated ring-opening metathesis polymer obtained after hydrogenation has excellent elongation at break and is suitable for downstream processing application.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis, and more particularly to a cyclic olefin compound, its preparation method, and its applications. Background Technology

[0002] Cyclic olefin monomers occupy an important position in the chemical industry due to their unique chemical structure and physical properties. Cyclic olefin compounds containing norbornene structures, in particular, are key materials in many high-end fields such as biomedicine, organic synthesis, and polymer synthesis. In the field of polymers, these compounds serve as core monomers for rubber and optical materials. Polymers prepared from them possess excellent heat resistance, light transmittance, and mechanical stability, demonstrating high-value-added application potential in the manufacture of high-end products such as precision instruments, electronic devices, and medical devices, thus becoming an important material basis for promoting the upgrading of related industries.

[0003] The synthesis of conventional cyclic olefin compounds, especially those containing the norbornene structure, generally involves a Diels-Alder reaction between dicyclopentadiene and an olefin under high temperature and pressure. US Patent 4168282A discloses a method for synthesizing norbornene from BF Goodrich, using a haloalkanes as solvent and dicyclopentadiene and ethylene as raw materials, reacting at 240–280°C. DuPont discloses a method for preparing norbornene using an inert aliphatic solvent, such as heptane, at 250–290°C. Chinese patent application CN117602998A discloses a method for preparing norbornene and tetracyclododecene, produced by the reaction of ethylene and dicyclopentadiene at 220–280°C. Chinese patent application CN112592248A discloses a method for preparing tetracyclododecene compounds, which involves an addition reaction at 230–260°C to prepare the corresponding cyclic olefin compound. While these high-temperature conditions can promote the cleavage of dicyclopentadiene to produce cyclopentadiene, which then undergoes an addition reaction with olefins, they also bring about many problems.

[0004] High-temperature environments not only cause side reactions between cyclopentadiene and dicyclopentadiene, generating various ineffective byproducts and resulting in significant waste of raw materials, but also increase energy consumption and safety risks during production, while the generated waste places additional pressure on the environment. Furthermore, to suppress side reactions, existing processes typically require a significant excess of olefin monomers, which further reduces the overall utilization rate of raw materials and increases production costs and the difficulty of subsequent separation and purification. Therefore, developing milder reaction conditions, reducing side reactions, and improving raw material utilization to achieve efficient and green synthesis of cyclic olefin compounds has become an urgent need for the industry, and is of great significance for promoting the energy-saving, green, and economical transformation of industrial production. Summary of the Invention

[0005] To address the aforementioned technical problems, the first aspect of this invention provides a method for preparing cyclic olefin compounds, comprising the following steps: Compound I and Compound II were added to a reactor and subjected to a Diels-Alder reaction at 100-200°C and 1-5 MPa to generate Compound III, a cyclic olefin compound. The structural formulas of compounds I, II, and III are as follows: ; In Formula I, R1 and R2 are independently H or C1-C4 alkyl groups, or R1 and R2 are connected to form a cyclic structure with 5 to 10 carbon atoms; n = 1 to 4.

[0006] As an implementable example, the molar ratio of compound I to compound II is (1~2):1.

[0007] The above-mentioned synthesis scheme, through specific reaction conditions and raw material structure design, specifically addresses the core pain points in the preparation of traditional cyclic olefin compounds, which rely on dicyclopentadiene as a raw material and require high-temperature cracking at 220~290℃, resulting in high energy consumption, high risk and easy to trigger side reactions, the need for a large excess of olefin monomers leading to low raw material utilization and serious waste, and the imbalance between high temperature and raw material ratio leading to an increase in by-products affecting product purity and subsequent polymerization application performance. This invention directly uses cyclic olefin compounds (compound I) as raw materials, eliminating the high-temperature cracking step and controlling the reaction temperature at 100~200℃, significantly reducing energy consumption and production hazards. It eliminates the need for excessive raw materials, with the molar ratio of compound I to compound II approaching the stoichiometric ratio (1~2):1, reducing raw material residue and waste and improving conversion efficiency. Simultaneously, the low-temperature environment and precise raw material design suppress side reactions such as self-polymerization and cross-linking, improving the purity of the target product, the cyclic olefin compound, and reducing impurity interference. Furthermore, the prepared cyclic olefin compound, when used for ring-opening metathesis polymerization, significantly improves the elongation at break of the hydrogenated polymer, enhancing material flexibility and meeting downstream processing requirements. Moreover, its low by-product and low energy consumption characteristics reduce waste emissions, aligning with the trends of green and energy-saving industrial production, and demonstrating strong process adaptability.

[0008] As an example of an feasible approach, the reaction time of the Diels-Alder reaction is 1 to 5 hours.

[0009] The Diels-Alder reaction is a typical [4+2] cycloaddition reaction. Compound I, a cyclic alkene, acts as the first reactant monomer, and compound II, cyclopentadiene, acts as a dienophile. The two react in a 1:1 molar ratio to generate a cyclic alkene compound of formula III. In this invention, the molar ratio of the two compounds is limited to (1~2):1. The core principle is to ensure the sufficiency of the reaction by using a moderate excess of compound I based on stoichiometric matching. If the molar ratio of compound I is less than 1:1, some of compound II will not be able to react fully with the diene, resulting in an increase in the residual amount of the raw material compound II, a decrease in the yield of the target product, and the possibility of side reactions such as self-polymerization of the excess compound II, which reduces the purity of the product. By controlling the molar ratio at (1~2):1, the stoichiometric requirements of the reaction are met, and the slight excess of formula I can drive the equilibrium towards the product, avoiding the problem of incomplete reaction caused by uneven local concentration of the raw materials.

[0010] As an feasible example, during the reactive synthesis of cyclic olefin compounds, compound II is added to the reactor to make the overall molar ratio of compound I to II 1 to 2:1.

[0011] As an feasible example, compounds I and II are both mixed with a solvent to form a solution before being added to the reactor.

[0012] Furthermore, the solvent includes one of n-hexane, cyclohexane, toluene, or xylene.

[0013] As an example of an implementable reaction, the described Diels-Alder reaction can be carried out in one of the following ways: batch reaction, semi-continuous reaction, or continuous reaction.

[0014] Furthermore, the Diels-Alder reaction described herein is either a semi-continuous reaction or a continuous reaction.

[0015] As an implementable example, the reactor includes a tubular reactor and / or a batch reactor.

[0016] A second aspect of the present invention provides a cyclic olefin compound prepared according to the above-described preparation method.

[0017] A third aspect of the present invention provides the application of cyclic olefin compounds in the synthesis of hydrogenated ring-opening metathesis polymers.

[0018] Using the aforementioned cyclic olefin compounds as all or part of the monomer raw materials, polymerization is carried out at 30–100°C under the action of a ring-opening metathesis catalyst to obtain a ring-opening metathesis polymer. Then, under the action of a hydrogenation catalyst, all double bonds in the ring-opening metathesis polymer are hydrogenated at 100–200°C to obtain a hydrogenated ring-opening metathesis polymer with a Dalton molecular weight in the range of 10,000–200,000. The ring-opening metathesis polymerization catalyst includes, but is not limited to, two-component and one-component ring-opening metathesis polymerization catalysts. The two-component ring-opening metathesis polymerization catalyst includes, but is not limited to, tungsten pentachloride, tungsten hexachloride, tungsten oxychloride, molybdenum pentachloride, molybdenum oxychloride, titanium tetrachloride, etc., as main catalysts, and triethylaluminum, triisobutylaluminum, ethoxydiethylaluminum, isobutoxydiisobutylaluminum, etc., as co-catalysts. The one-component catalyst includes, but is not limited to, Schrock catalysts, first-generation Grubbs catalysts, second-generation Grubbs catalysts, third-generation Grubbs catalysts, etc. The hydrogenation catalyst includes homogeneous and heterogeneous catalysts. The homogeneous catalyst includes, but is not limited to, catalysts composed of compounds such as nickel naphthenate and alkylaluminum such as triisobutylaluminum, and the heterogeneous catalyst includes, but is not limited to, nickel catalysts supported on Pd / C, diatomaceous earth, or Al2O3. Hydrogenated ring-opening metasomatic polymers prepared from the above-mentioned cyclic olefin compounds exhibit higher elongation at break.

[0019] Beneficial effects (i) This invention uses cyclopentadiene directly as raw material, eliminating the high-temperature cracking step of dicyclopentadiene. The reaction temperature is only 100~200℃, which is much lower than the 220~290℃ of the traditional process, greatly reducing the energy consumption of the equipment and reducing the production risk.

[0020] (ii) The raw materials synthesized in this invention do not contain dicyclopentadiene, and the low-temperature reaction environment inhibits side reactions such as self-polymerization of cyclopentadiene and cross-linking with dicyclopentadiene. The proportion of by-products is only 0.7%~1.1%, which is much lower than that of traditional processes, thereby improving the purity of the product while reducing environmental pressure.

[0021] (iii) In this invention, there is no need to suppress side reactions by using a large excess of olefin monomers. The molar ratio of compound I to II is controlled at (1~2):1, which is close to the stoichiometric ratio. The residual amount of raw materials is significantly reduced, avoiding waste of raw materials and reducing production costs.

[0022] (iv) When the cyclic olefin compounds prepared by this invention are used for ring-opening metathesis polymerization, the resulting hydrogenated ring-opening metathesis polymers have a tensile elongation at break of 43.1% to 75.2%, which is far superior to traditional monomer polymerization products, greatly improving the flexibility of the polymer and adapting to downstream processing requirements.

[0023] (v) The reaction provided in this invention can be carried out in batch, semi-continuous or continuous mode, and is compatible with tubular, batch and combined reactors, and is flexible in operation; it has the characteristics of low energy consumption, low by-products and high raw material conversion rate, which is in line with the trend of energy-saving and green development in industrial production. Detailed Implementation

[0024] The purity information of the raw materials involved in this invention is as follows: Cyclopentadiene, purity 99.9%;

[0025] Dicyclopentadiene, purity 99.5%;

[0026] Cyclopentene, purity 99.5%;

[0027] Methylcyclopentene, purity 99.5%;

[0028] Cyclohexene, purity 99.5%;

[0029] Indene, 98% purity;

[0030] Norbornene, purity 99.5%;

[0031] Tetracyclododecene (CAS No.: 21635-90-5), purity 99%;

[0032] Cyclohexane, purity 99.5%; 1-Hexene, purity 99.5%; Nitrogen gas, 99.99% purity; Hydrogen gas, 99.99% purity; First-generation Grubbs catalyst (benzyl methylene dichlorobis(tricyclohexylphosphine)ruthenium), purity 97%; Pd / C, 10wt% Pd.

[0033] The composition of the cyclic olefin compounds obtained in the reaction of this application was determined by gas chromatography (manufacturer: Agilent, model 7820A). The weight-average molecular weight of the polymer was determined using a high-temperature gel permeation chromatography system (Varian, model PL-220), with polystyrene as the standard and trichlorobenzene as the mobile phase, at 135°C. Polymer elongation at break is measured by preparing dumbbell-shaped tensile specimens of polymer (GB / T 1040.2-2018, type 1A) and testing them using a universal tensile testing machine (manufacturer SHIMADZU, model EZ-LX).

[0034] Example 1 This example provides a method for preparing a cyclic olefin compound, comprising the following steps: 300 g of a cyclohexane solution containing 90 wt% cyclopentene (compound I) and 150 g of a cyclohexane solution containing 90 wt% cyclopentadiene (compound II) were added to a 1 L pre-dried and nitrogen-purged batch reactor. The molar ratio of cyclopentene to cyclopentadiene was 1.94:1. The reaction was then carried out at 150 °C and 3 MPa for 3 h in a batch manner to generate a cyclic olefin compound (compound III). The product was analyzed by gas chromatography, and the component information is listed in Table 1.

[0035] The second aspect of this example provides a cyclic olefin compound prepared according to the above-described method for preparing cyclic olefin compounds.

[0036] Example 2 This example provides a method for preparing a cyclic olefin compound, comprising the following steps: 300 g of a cyclohexane solution of 90 wt% cyclopentene (compound I) and 50 g of a cyclohexane solution of 90 wt% cyclopentadiene (compound II) were added to a 1 L pre-dried and nitrogen-purged batch reactor. The system was heated to 150 °C and the pressure was controlled at 3 MPa with nitrogen. Then, 100 g of a cyclohexane solution of 90 wt% cyclopentadiene was added over 2 h. The molar ratio of cyclopentene to cyclopentadiene was 1.94:1. The semi-continuous reaction was continued for 1 h to generate a cyclic olefin compound (compound III). The product was analyzed by gas chromatography, and the component information is listed in Table 1.

[0037] Example 3 The specific implementation method in this example is the same as in Example 2, except that 200g of a cyclohexane solution containing 90wt% cyclopentene (compound I) is added, and the molar ratio of cyclopentene to cyclopentadiene is 1.29:1.

[0038] Example 4 This example provides a method for preparing a cyclic olefin compound, comprising the following steps: In a 1L pre-dried and nitrogen-purged batch reactor, 300g of a cyclohexane solution of 90wt% indene (compound I) and 50g of a cyclohexane solution of 90wt% cyclopentadiene (compound II) were added. The system was heated to 150°C, and the pressure was controlled at 3MPa with nitrogen. Then, 50g of a cyclohexane solution of 90wt% cyclopentadiene was added over 2 hours. The molar ratio of cyclopentadiene to cyclopentadiene was 1.71:1. The semi-continuous reaction was continued for 1 hour to generate a cyclic olefin compound (compound III). The product was analyzed by gas chromatography, and the component information is listed in Table 1.

[0039] Comparative Example 1 This example provides a method for preparing a cyclic olefin compound, comprising the following steps: 300 g of a cyclohexane solution of 90 wt% cyclopentene (compound I) and 150 g of a cyclohexane solution of 90 wt% dicyclopentadiene were added to a 1 L pre-dried and nitrogen-purged batch reactor. The molar ratio of cyclopentene to cyclopentadiene was 3.88:1. The reaction was then carried out at 150 °C and 3 MPa for 3 h in a batch manner to generate cyclic olefin compounds. The products were analyzed by gas chromatography, and the component information is listed in Table 1.

[0040] Comparative Example 2 This example provides a method for preparing a cyclic olefin compound, comprising the following steps: 300 g of a cyclohexane solution of 90 wt% cyclopentene (compound I) and 50 g of a cyclohexane solution of 90 wt% dicyclopentadiene were added to a 1 L pre-dried and nitrogen-purged batch reactor. The system was heated to 150 °C and the pressure was controlled at 3 MPa with nitrogen. Then, 100 g of a cyclohexane solution of 90 wt% dicyclopentadiene was added over 2 h. The molar ratio of cyclopentene to cyclopentadiene was 1.94:1. The reaction was continued for 1 h to generate a cyclic olefin compound (compound III). The product was analyzed by gas chromatography, and the component information is listed in Table 1.

[0041] Table 1

[0042] As shown in Table 1, when preparing cyclic olefin compounds using the technical solution of the present invention, the raw material conversion rate is higher, the yield of the target product is higher, and the by-products are fewer.

[0043] Application Example 1 This example provides an application of a cyclic olefin compound in the preparation of hydrogenated ring-opening metathesis polymers, comprising the following steps: In a 1L reactor that has been pre-dried and purged with nitrogen, 120g of product compound III dihydrodicyclopentadiene, 12g of 1-hexene (reactant monomer), 368g of cyclohexane, and 2.2g of ethoxydiethylaluminum from Example 1 were added. The system was heated to 50°C, and 75g of a toluene solution of molybdenum pentachloride (5wt%) was added with stirring. After reacting for 3 hours, a sample was taken to monitor the monomer conversion rate, and the monomers in the system were completely converted. The solution was poured into acetone, precipitating the polymer, which was then filtered and dried to obtain the ring-opening metathesis polymer.

[0044] The ring-opening translocation polymer was dissolved in 400 g of cyclohexane and added to a 1 L high-pressure reactor that had been pre-dried and purged with nitrogen. 12 g of Pd / C catalyst (10 wt% Pd) was also added. The system was reacted at 200 °C and 5 MPa hydrogen pressure for 3 h to prepare the hydrogenated ring-opening translocation polymer. After the reaction, the temperature was lowered, the hydrogen gas was released, and samples of the reaction solution were taken to test the hydrogenation of the polymer. It was found that the double bonds had been completely hydrogenated. The molecular weight and tensile elongation at break of the obtained hydrogenated ring-opening translocation polymer were measured, and the results are listed in Table 2.

[0045] Application Example 2 The specific implementation method in this example is the same as in Application Example 1, except that product compound III in Application Example 1 is replaced with product compound III (1,4-methylene-1,4,4a,9a-tetrahydrofluorene) in Example 4. The molecular weight and tensile elongation at break of the resulting polymer were tested, and the results are listed in Table 2.

[0046] Application Example 3 The specific implementation method of this example is the same as that of Application Example 1, except that: product compound III in Application Example 1 is replaced with 60g of norbornene and 60g of product compound III dihydrodicyclopentadiene in Example 1.

[0047] Application Example 4 The specific implementation method of this example is the same as that of Application Example 1, except that: product compound III in Application Example 1 is replaced with 60g of norbornene, and product compound III (1,4-methylene-1,4,4a,9a-tetrahydrofluorene) 60g in Example 4.

[0048] Application Example 5 The specific implementation method of this example is the same as that of Application Example 1, except that: product compound III in Application Example 1 is replaced with 60g of tetracyclododecene and 60g of product compound III (1,4-methylene-1,4,4a,9a-tetrahydrofluorene) in Example 4.

[0049] Comparative Application Example 1 The specific implementation method in this example is the same as in Application Example 1, except that product compound III in Application Example 1 is replaced with 120g of norbornene.

[0050] Comparative Application Example 2 The specific implementation method in this example is the same as in Application Example 1, except that the product compound III in Application Example 1 is replaced with 120g of tetracyclododecene.

[0051] Comparative Application Example 3 The specific implementation method of this example is the same as that of Application Example 1, except that the product compound III in Application Example 1 is replaced with 60g of norbornene and 60g of tetracyclododecene.

[0052] The molecular weight (kDalton) and tensile elongation at break (%) of the hydrogenated ring-opening metathesis polymers prepared in Application Examples 1-5 were compared with those in Application Examples 1-3. The test results are detailed in Table 2.

[0053] Table 2

[0054] As shown in Table 2, the cyclic olefin compounds prepared using the technical solution of this invention, when homopolymerized or copolymerized with other cyclic olefin monomers and then hydrogenated to prepare hydrogenated ring-opening metathesis polymers, can yield polymers with high tensile elongation at break. That is, the addition of the cyclic olefin compounds provided by this invention can improve the flexibility of polymers that originally had low tensile elongation at break.

Claims

1. A method for preparing a cyclic olefin compound, characterized in that, Includes the following steps: Compound I and Compound II were added to a reactor and subjected to a Diels-Alder reaction at 100-200°C and 1-5 MPa to generate Compound III, a cyclic olefin compound. The structural formulas of compounds I, II, and III are as follows: ； In Formula I, R1 and R2 are independently one of H or C1-C4 alkyl groups, or R1 and R2 are connected to form a cyclic structure with 5 to 10 carbon atoms; n = 1 to 4; The molar ratio of compound I to compound II is (1~2):1; The reaction time for the Diels-Alder reaction is 1 to 5 hours.

2. The method for preparing the cyclic olefin compound according to claim 1, characterized in that, Both compounds I and II were mixed with a solvent to form a solution before being added to the reactor.

3. The method for preparing the cyclic olefin compound according to claim 1, characterized in that, The solvent includes one of n-hexane, cyclohexane, toluene, or xylene.

4. The method for preparing the cyclic olefin compound according to claim 1, characterized in that, The Diels-Alder reaction can be carried out in one of the following ways: batch reaction, semi-continuous reaction, or continuous reaction.

5. The method for preparing the cyclic olefin compound according to claim 1, characterized in that, The reactors include tubular reactors and / or batch reactors.

6. A cyclic olefin compound prepared by a method according to any one of claims 1-5.

7. An application of the cyclic olefin compound according to claim 6, characterized in that, It is used in the synthesis of hydrogenated ring-opening metasomatic polymers.

8. The application of the cyclic olefin compound according to claim 7, characterized in that, The synthesis of the hydrogenated ring-opening metathesis polymer includes the following steps: Cyclic olefin compounds and ring-opening metathesis catalysts are mixed and polymerized to obtain ring-opening metathesis polymers; the ring-opening metathesis polymers are mixed and hydrogenated to obtain hydrogenated ring-opening metathesis polymers.

9. The application of the cyclic olefin compound according to claim 8, characterized in that, The polymerization reaction is carried out at a temperature of 30~100℃.

10. The application of the cyclic olefin compound according to claim 8, characterized in that, The hydrogenation reaction is carried out at a temperature of 100~200℃.

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