Method for preparing norbornene with low energy consumption and short process and application thereof

Abstract

The invention relates to the technical field of preparation of cycloolefin copolymer monomers, and discloses a method for preparing norbornene with low energy consumption and a short process and application thereof. The method provided by the invention is suitable for synthesizing the norbornene synthetic liquid by a solvent method and purifying the norbornene synthetic liquid, and the norbornene solution which can be directly used in polymerization is obtained through two-step purification. The method can obtain the norbornene solution suitable for COC synthesis at a high yield, and has the advantages of short process flow, high resource utilization rate, reliable process, easiness in management, easiness in industrial popularization and the like.

Description

Technical Field

[0001] This invention relates to the field of cyclic olefin copolymer monomer preparation technology, specifically to a low-energy, short-process method for preparing norbornene and its application. Background Technology

[0002] Cycloolefin copolymers (COCs) are copolymers of cycloolefins and α-olefins. They not only have good processability, but also excellent thermal, optical, mechanical and hygienic properties, and can be widely used in optics, electronics and medicine.

[0003] Currently, mature COC production processes typically involve reacting norbornene with α-olefins such as ethylene as comonomers. Norbornene is usually prepared by the Diels-Alder cycloaddition reaction of cyclopentadiene and ethylene under high temperature and high pressure. Its purity has a significant impact on the performance (such as transparency) and quality of COC products. Therefore, controlling the purity of norbornene is crucial for the production of high-quality COC products.

[0004] The synthesis of norbornene can be divided into two categories: solvent-based and solvent-free. The use of solvents can reduce the formation of heavy components and alleviate equipment coking and clogging, so most industrial processes currently use solvent-based processes. However, the norbornene synthesis solution obtained by solvent-based processes has a more complex composition, including solvents, unreacted raw materials, new components generated by the reaction, impurities and products introduced by the raw materials, and impurities generated by side reactions. Moreover, during the separation process, some impurities can interconvert, leading to problems such as difficulty in purifying high-purity norbornene, long process flow, high energy consumption during processing, and high management difficulty.

[0005] Typically, to obtain high-purity norbornene, it is necessary to remove as much of the solvent, unreacted raw materials, impurities and products introduced from the raw materials, and impurities generated by side reactions as possible from the norbornene synthesis solution during the separation process. However, such separation methods are not only energy-intensive and lengthy, resulting in high separation costs, but also may cause problems such as a decline in product quality during subsequent COC production due to the generation of new impurities from the norbornene reaction during the separation process. In addition, in solvent-based processes, since the solvent is usually separated together with the heavy components, it is difficult to directly reuse it in production. Further solvent separation can easily lead to a further extension of the process and a further increase in costs, while direct disposal will result in a significant waste of resources. Summary of the Invention

[0006] The purpose of this invention is to overcome the aforementioned problems in the prior art and provide a low-energy, short-process method for preparing norbornene and its applications. The method provided by this invention, by selecting a specific solvent during the synthesis process and separating the solvent and norbornene together during the separation process, reduces the cost of solvent separation, lowers energy consumption, simplifies the process flow, and makes full use of resources, making the method more in line with green and sustainable development requirements.

[0007] To achieve the above objectives, a first aspect of the present invention provides a method for preparing norbornene with low energy consumption and a short process, the method comprising:

[0008] (1) Norbornene synthesis: In the presence of a solvent, dicyclopentadiene and ethylene are introduced into a reactor to react and obtain a norbornene synthesis solution;

[0009] The reaction conditions ensure that the conversion rate of dicyclopentadiene is not less than 90%.

[0010] The solvent is an organic solvent that does not react in the reaction system;

[0011] (2) Norbornene separation: The norbornene synthesis solution is separated to remove the light and heavy components to obtain a norbornene solution;

[0012] The norbornene solution contains norbornene and a solvent, and the content of cyclopentadiene therein does not exceed 100 ppm.

[0013] The second aspect of the present invention provides the application of the method described in the first aspect in improving the quality of cyclic olefin copolymer products.

[0014] A third aspect of the present invention provides a method for preparing high-quality cyclic olefin copolymers, the method comprising: using a norbornene solution prepared according to the method described in the first aspect as a raw material in the synthesis of the cyclic olefin copolymer.

[0015] Through the above technical solution, the present invention can achieve at least the following beneficial effects:

[0016] (1) The method provided by the present invention simplifies the purification process of norbornene synthesis liquid obtained by solvent synthesis, and at the same time minimizes the content of impurities in the separated norbornene liquid that may affect the quality of COC products, it also has the advantages of low energy consumption, reliable process and convenient management in the separation and purification process, and is suitable for industrial-scale production and promotion.

[0017] (2) The method provided by the present invention does not separate norbornene and solvent. By selecting solvents that are suitable for both norbornene synthesis and COC synthesis, the separated norbornene solution (mainly composed of norbornene and solvent) is directly used in the subsequent COC synthesis process. On the one hand, this reduces the repeated addition and separation of solvents and avoids solvent waste. On the other hand, by simplifying the process flow, it reduces the generation of by-products during the separation process, making the quality of COC products more controllable. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the method for preparing norbornene from dicyclopentadiene and ethylene used in the examples.

[0019] Explanation of reference numerals in the attached figures

[0020] R-1: Reactor; V-1: Gas-liquid separator; C-1: Compressor; T-1: Heavy removal tower; T-2: Light removal tower; E-1: Heavy removal tower top condenser; E-2: Low-temperature condenser for the gaseous stream at the top of the heavy removal tower; E-3: Light removal tower top condenser;

[0021] S-1: Ethylene; S-2: Dicyclopentadiene solution; S-3: Reaction product stream; S-4: Recycled ethylene stream; S-5: Reaction liquid; S-6: Gas stream from the top of the heavy removal tower; S-7: Liquid stream from the top of the heavy removal tower; S-8: Bottom stream from the heavy removal tower; S-9: Non-condensable gas stream from the top of the light removal tower; S-10: Liquid stream from the top of the light removal tower; S-11: Bottom stream from the light removal tower. Detailed Implementation

[0022] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0023] In this invention, unless otherwise specified, "heavy components" refer to components in the norbornene synthesis solution with boiling points higher than those of norbornene and the solvent, including, for example, dicyclopentadiene, tricyclopentadiene, tetracyclododecene, etc.; "light components" refer to components in the norbornene synthesis solution with boiling points lower than those of norbornene and the solvent, mainly including light components carried by the reactants themselves, as well as impurities generated from the conversion of the reactants or carried in the reactants (such as cyclopentadiene, isoprene, isoprene, etc.).

[0024] In this invention, unless otherwise specified, the theoretical plate number is obtained experimentally using a method commonly used in the field of separation.

[0025] In this invention, unless otherwise specified, the operation numbers (such as "first" and "second" in "first distillation" and "second distillation") are only used to facilitate the differentiation of the same process in different steps in the description, and do not limit the specific operation method, conditions, and sequence.

[0026] In this invention, unless otherwise specified, "ppm" refers to parts per million by mass, and 100ppm = 0.01% by weight.

[0027] Currently, conventional COC production processes first require the synthesis of norbornene, which mainly involves the synthesis and purification of norbornene. To improve COC quality, the purification process is typically required to maximize the purity of norbornene, especially removing impurities such as cyclopentadiene that may affect COC quality. For norbornene synthesis processes involving solvents, the solvent usually needs to be separated during purification. However, in COC synthesis, the norbornene monomer needs to be dissolved in an organic solvent to form a solution, and then copolymerized with α-olefins such as ethylene under the action of a catalyst to generate cyclic olefin copolymers. Therefore, both norbornene synthesis and COC synthesis require the addition of large amounts of solvent. The production method of separating the solvent during norbornene purification and then adding a large amount of solvent during COC synthesis is not only lengthy and energy-intensive, but also shows significant resource inefficiency. Furthermore, during the separation of norbornene and solvent, norbornene may react to generate new impurities, leading to problems such as a decline in COC quality. Furthermore, norbornene is a solid at room temperature, which can easily cause blockages in pipelines and equipment, making it difficult to operate.

[0028] The inventors of this invention ingeniously discovered during their research that, by selecting a specific solvent, after the synthesis of norbornene is completed, only the residual amount of impurities such as cyclopentadiene that may affect the quality of COC needs to be controlled in the norbornene during separation. The solvent is retained and separated together with the norbornene as raw material for the next step of COC synthesis. This not only saves energy consumption in the separation process of norbornene and solvent, as well as the redissolution process of norbornene, and avoids the problem of solid norbornene clogging pipelines and equipment, but also simplifies the overall process of COC production. In addition, it can save a large amount of solvent and reduce production costs.

[0029] Based on this, the first aspect of the present invention provides a method for preparing norbornene with low energy consumption and a short process, the method comprising:

[0030] (1) Norbornene synthesis: In the presence of a solvent, dicyclopentadiene and ethylene are introduced into a reactor to react and obtain a norbornene synthesis solution;

[0031] The reaction conditions ensure that the conversion rate of dicyclopentadiene is not less than 90%.

[0032] The solvent is an organic solvent that does not react in the reaction system;

[0033] (2) Norbornene separation: The norbornene synthesis solution is separated to remove the light and heavy components to obtain a norbornene solution;

[0034] The norbornene solution contains norbornene and a solvent, and the content of cyclopentadiene therein does not exceed 100 ppm.

[0035] To improve the reaction rate and selectivity of norbornene, step (1) can typically be carried out with an excess of ethylene. According to a preferred embodiment of the invention, in step (1), the molar ratio of dicyclopentadiene to ethylene is 1:6-60, preferably 1:6-30. For example, it can be 1:6, 1:8, 1:10, 1:12, 1:14, 1:16, 1:18, 1:20, 1:22, 1:24, 1:26, 1:28, 1:30, or any intermediate value within the range formed by any two of the above ratios.

[0036] The present invention does not impose any particular limitation on the specific feeding method in step (1), and conventional methods in the art can be used. According to some preferred embodiments of the present invention, step (1) includes preparing a dicyclopentadiene solution by reacting a solvent with dicyclopentadiene, and introducing the dicyclopentadiene solution with ethylene into a reactor for reaction.

[0037] To maximize the selectivity of norbornene, the concentration of the dicyclopentadiene solution should be reduced. However, if the concentration of the dicyclopentadiene solution is too low, it will lead to increased energy consumption. Considering both norbornene selectivity and energy consumption, preferably, in step (1), the amount of solvent used is such that the concentration of dicyclopentadiene in the dicyclopentadiene solution is 10-75% by weight, preferably 30-55% by weight.

[0038] In this invention, "organic solvents that do not react in the reaction system" refers to organic solvents that do not react themselves under reactive or non-reactive conditions, and do not react with reactants, reaction products, intermediate products, by-products, etc.

[0039] In this invention, the purpose of step (1) is to synthesize norbornene from cyclopentadiene and ethylene. During the reaction, dicyclopentadiene undergoes depolymerization to generate cyclopentadiene, which then reacts with ethylene via a Diels-Alder reaction to synthesize norbornene. The main function of the solvent is to reduce the probability of collision between cyclopentadiene and dicyclopentadiene, preventing them from reacting to form tricyclopentadiene or a heavier component. Considering the purpose of this invention, the solvent preferably has a boiling point close to that of norbornene, and it is carefully ensured that the norbornene synthesis solution contains no substances with boiling points between norbornene and the solvent.

[0040] Those skilled in the art can select suitable solvents based on the above principles and the needs of norbornene and COC synthesis. According to some preferred embodiments of the present invention, the solvent is selected from at least one of benzene, benzene derivatives with no more than 10 carbon atoms, straight-chain alkanes or cycloalkanes with 5-10 carbon atoms.

[0041] Preferably, the solvent is selected from at least one of benzene, toluene, xylene, cyclohexane, heptane, octane, and decahydronaphthalene.

[0042] To improve the synthesis efficiency of norbornene, according to a preferred embodiment of the present invention, in step (1), the reaction conditions are such that the conversion rate of dicyclopentadiene is not less than 95%, preferably not less than 98%, and more preferably not less than 99%. For example, it can be 95%, 96%, 97%, 98%, 99%, 99.5%, 99.8%, 99.9%, or any range consisting of any two of the above values, or any intermediate value within the above range. In the present invention, controlling the conversion rate of dicyclopentadiene in step (1) to reach the above levels can, on the one hand, sufficiently improve the utilization rate of dicyclopentadiene and reduce the consumption in the separation process, and on the other hand, reduce the possibility of dicyclopentadiene reacting and generating other byproducts in the subsequent separation process.

[0043] In order to ensure that ethylene and cyclopentadiene are in full contact and increase the proportion of ethylene per unit volume, a higher reaction pressure can be selected in step (1). In order to accelerate the reaction rate between cyclopentadiene and ethylene, the reaction temperature can also be appropriately increased.

[0044] Based on the above principles, according to some preferred embodiments of the present invention, the reaction conditions include: temperature 160-300℃ and pressure 5-20MPa.

[0045] Preferably, the reaction conditions include: temperature 180-260℃ and pressure 8-16MPa.

[0046] According to some preferred embodiments of the present invention, step (1) further includes separating ethylene from the reaction products to recover unreacted ethylene. The recovered ethylene can be recycled back to the reaction in step (1) after pressurization, for example, it can be mixed with fresh ethylene and introduced into the reactor as a reaction feedstock. In addition, the liquid phase obtained after gas-liquid separation (i.e., norbornene synthesis liquid) may still contain a small amount of ethylene. This portion of ethylene can be recovered by depressurization before the separation treatment in step (2), or it can be separated together with the light components in step (2) and then further separated and recovered. These recovered ethylene can all be recycled as feedstock after pressurization to improve the utilization rate of feedstock and reduce the cost of feedstock.

[0047] To ensure that the obtained norbornene solution meets the requirements for high-quality COC polymerization production, the content of impurities such as cyclopentadiene, which affect COC quality, should be strictly controlled. Generally, to meet the requirements of high-quality COC production, the cyclopentadiene content in the norbornene separation solution introduced into the polymerization process should not exceed 100 ppm. For example, it can be 100 ppm, 80 ppm, 60 ppm, 40 ppm, 20 ppm, 10 ppm, 5 ppm, 4 ppm, 3 ppm, 2 ppm, 1 ppm, or 0, or any intermediate value within any range of the above two values.

[0048] According to a preferred embodiment of the present invention, in step (2), the content of cyclopentadiene in the norbornene solution is not more than 50 ppm, preferably not more than 10 ppm.

[0049] In this invention, there are no particular restrictions on the specific method for separating and obtaining the norbornene solution (the main components are norbornene + solvent, which can also be referred to as "norbornene separation liquid" in this invention). Any separation method that can achieve the above purpose is applicable to this invention.

[0050] The inventors of this invention ingeniously discovered during their research that by controlling the distillation conditions in conjunction with the structural features of the distillation column, such as the number of theoretical plates, inlet position, and outlet position, the norbornene synthesis liquid can be directly separated into two parts: (from the top of the column) a light component + norbornene + solvent, and (from the bottom of the column) a heavy component. Further separation to remove the light component yields the norbornene solution. In this method, by controlling the content of the heavy component in the light component + norbornene + solvent stream, the content of high-boiling-point impurities in the obtained norbornene solution can be effectively controlled, thus obtaining a norbornene solution with a lower content of heavy components. This method requires only two steps to obtain the norbornene solution, eliminating the need to separate norbornene from the solvent. It can be directly used for polymerization reactions, offering advantages such as a short process flow, low equipment investment, and high processing efficiency. Furthermore, it avoids the reaction between norbornene and the solvent during separation, preventing the regeneration of light or heavy components, and eliminates the need for preparing the norbornene solution before polymerization, improving resource utilization and reducing waste.

[0051] Based on this, according to some preferred embodiments of the present invention, step (2) includes:

[0052] (2-1) De-weighting: The norbornene synthesis liquid is introduced into the de-weighting tower for the first distillation. The top stream of the de-weighting tower containing light components, norbornene and solvent is collected from the top of the tower, and the bottom stream of the de-weighting tower containing heavy components is collected from the bottom of the tower.

[0053] The conditions for the first distillation are such that the amount of norbornene and solvent entering the bottom stream of the deweighting tower does not exceed 10% by weight of the amount of norbornene and solvent in the norbornene synthesis liquid (in order to reduce the loss of norbornene and solvent).

[0054] (2-2) Light removal: The overhead stream obtained in step (2-1) is introduced into the light removal column for a second distillation. The overhead stream containing cyclopentadiene is collected from the top of the column, and the norbornene solution containing norbornene and solvent is collected from the bottom of the column.

[0055] In this invention, the purpose of step (2-1) is to remove heavy components from the norbornene synthesis solution. The remaining portion of the synthesis solution after the heavy components have been removed (i.e., the overhead stream from the de-heavy component removal column) can be further separated to obtain a norbornene solution. In order to ensure that the norbornene solution meets the requirements of COC synthesis, heavy components should be kept away from the overhead stream from the de-heavy component removal column as much as possible in step (2-1).

[0056] According to a preferred embodiment of the present invention, in step (2-1), the conditions of the first distillation are such that the total content of heavy components (impurities) in the overhead stream of the de-heavy column does not exceed 0.5% by weight, preferably not more than 0.3% by weight, and more preferably not more than 0.1% by weight.

[0057] According to a preferred embodiment of the invention, the conditions of the first distillation are such that the amount of norbornene and solvent entering the bottom stream of the deweighting tower does not exceed 5% by weight of the amount of norbornene and solvent in the norbornene synthesis solution. For example, it can be 10% by weight, 9% by weight, 8% by weight, 7% by weight, 6% by weight, 5% by weight, 4% by weight, 3% by weight, 2% by weight, 1% by weight, 0.5% by weight, or 0%, or any intermediate value within any range of any two of the above values.

[0058] According to a preferred embodiment of the present invention, in step (2-1), the theoretical number of plates in the deweighting tower is 20-55.

[0059] Dicyclopentadiene and tetracyclododecene undergo depolymerization at higher temperatures. Dicyclopentadiene depolymerizes into cyclopentadiene, and tetracyclododecene depolymerizes into cyclopentadiene and norbornene. Cyclopentadiene can react with substances containing carbon-carbon double bonds in heavy components to undergo Diels-Alder diene synthesis, generating heavier components that easily cause coking and blockage in the equipment. Therefore, to reduce coking, reduced pressure or (close to) atmospheric pressure operating conditions are preferred in the decoupling column. Preferably, the conditions for the first distillation include: a column top pressure of 20-105 kPa and a column top temperature of 40-80°C.

[0060] For example, the top pressure of the first distillation column can be 20 kPa, 30 kPa, 40 kPa, 50 kPa, 60 kPa, 70 kPa, 80 kPa, 90 kPa, 100 kPa, or 105 kPa, or any intermediate value within the range of any two of the above values.

[0061] For example, the top temperature of the first distillation column can be 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, or 80°C, or any intermediate value within the range of any two of the above values.

[0062] More preferably, the conditions for the first distillation also include: a bottom temperature of 100-180°C, preferably 110-160°C.

[0063] For example, the bottom temperature of the first distillation column can be 100℃, 110℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃, 155℃, or 160℃, or any intermediate value within the range of any two of the above values.

[0064] More preferably, the reflux ratio of the first distillation is 1-6, and more preferably 2-5.

[0065] According to a preferred embodiment of the invention, the norbornene synthesis solution can be fed near the middle of the deweighting tower. For example, it can be fed at 2 / 5 to 3 / 5 of the theoretical plate or packing from top to bottom.

[0066] In this invention, the purpose of step (2-2) is to remove light components from the overhead stream of the de-heavy stream to obtain a norbornene solution. To obtain a norbornene solution that meets the requirements for COC synthesis, light component impurities in the overhead stream of the de-heavy stream should be removed as much as possible. Simultaneously, it is important to avoid converting some light components into heavy component impurities during the removal process, which would reduce the quality of the norbornene solution.

[0067] According to a preferred embodiment of the present invention, in step (2-2), the conditions of the second distillation are such that the content of cyclopentadiene in the norbornene solution does not exceed 100 ppm, preferably not more than 50 ppm, and more preferably not more than 10 ppm. For example, it can be 100 ppm, 80 ppm, 60 ppm, 40 ppm, 20 ppm, 10 ppm, 5 ppm, 4 ppm, 3 ppm, 2 ppm, 1 ppm, or 0, or it can be any intermediate value within any range of any two of the above values.

[0068] In order to ensure that the component content in the norbornene solution stream meets the aforementioned requirements, according to a preferred embodiment of the present invention, in step (2-2), the theoretical number of plates in the light-light removal tower is 15-50.

[0069] According to a preferred embodiment of the present invention, the second distillation is carried out under reduced pressure or atmospheric pressure.

[0070] Preferably, the conditions for the second distillation include: a top pressure of 30-110 kPa and a top temperature of 45-100°C.

[0071] More preferably, the conditions for the second distillation include: a top pressure of 50-110 kPa and a top temperature of 55-100 °C.

[0072] For example, the top pressure of the second distillation column can be 50 kPa, 60 kPa, 70 kPa, 80 kPa, 90 kPa, 100 kPa, or 110 kPa, or any intermediate value within the range of any two of the above values.

[0073] For example, the top temperature of the second distillation column can be 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, or 100°C, or any intermediate value within the range of any two of the above values.

[0074] To prevent light component impurities from converting into heavy component impurities and entering the norbornene solution, the bottom temperature of the second distillation column should be controlled. Preferably, the conditions for the second distillation also include a bottom temperature of 75-110°C, more preferably 80-110°C.

[0075] For example, the bottom temperature of the second distillation column can be 80℃, 85℃, 90℃, 95℃, 100℃, or any intermediate value between any two of the above values.

[0076] In order to ensure that the component content of each stream collected from the light distillation tower meets the aforementioned requirements, preferably, the reflux ratio of the second distillation is 10-35, more preferably 20-30.

[0077] According to a preferred embodiment of the invention, the top stream of the heavy-weight removal tower can be fed near the middle of the light-weight removal tower. For example, it can be fed from 1 / 3 to 2 / 3 of the way down from the top of the theoretical plate or packing.

[0078] Considering that tetracyclododecene and dicyclopentadiene are also important raw materials for cyclic olefin copolymers, and that in steps (2-1) and (2-2) a portion of norbornene and / or solvent is lost to ensure that the impurity content in the final norbornene solution meets the requirements, for example, in step (2-1), some norbornene and solvent enter the bottom stream of the heavy removal tower, and in step (2-2), some norbornene may enter the top stream of the light removal tower. Therefore, to further improve the economic efficiency of the method provided by the present invention, according to a preferred embodiment of the present invention, the method further includes:

[0079] (2-3) Material recovery: at least one of dicyclopentadiene, tetracyclododecene and solvent in the bottom stream of the heavy removal tower, and / or, cyclopentadiene and / or norbornene in the top stream of the light removal tower.

[0080] Furthermore, the method provided by this invention may also include the utilization of the recovered materials. For example, dicyclopentadiene and cyclopentadiene can be recycled to the reactor; norbornene can be recycled to the reactor or purification system as appropriate; tetracyclododecene is a much-needed cyclic olefin copolymer monomer after purification.

[0081] Since the method provided by this invention can obtain a norbornene solution with extremely low impurity content (especially impurities such as cyclopentadiene that have a significant impact on COC quality), the quality of COC products can be effectively improved by using this norbornene solution as a raw material for COC production. Based on this, a second aspect of this invention provides the application of the method described in the first aspect in improving the quality of cyclic olefin copolymer products.

[0082] A third aspect of the present invention provides a method for preparing high-quality cyclic olefin copolymers, the method comprising: using a norbornene solution prepared by the method described in the first aspect as a raw material in the synthesis of the cyclic olefin copolymer.

[0083] The present invention will be described in detail below through embodiments. It should be understood that the following embodiments are only used to further explain and illustrate the content of the present invention by way of example, and are not intended to limit the present invention.

[0084] Unless otherwise specified, all reagents used in the following examples are commercially available products purchased from legitimate chemical suppliers and are of analytical grade.

[0085] Example 1

[0086] use Figure 1 The system shown synthesizes norbornene from dicyclopentadiene and ethylene according to the following method, and then a norbornene solution is obtained by separation from the synthesis solution. The flow rates and compositions of each step are detailed in Table 1.

[0087] (1) Synthesis: A dicyclopentadiene solution with a concentration of 50% by weight was prepared using toluene as a solvent. The dicyclopentadiene solution S-2 and ethylene S-1 were introduced into reactor R-1, with the molar ratio of dicyclopentadiene to ethylene entering reactor R-1 controlled at 1:15. The reaction was carried out under conditions of 12 MPa pressure and 240 °C, achieving a dicyclopentadiene conversion rate of 98.5%.

[0088] The generated reaction product stream S-3 is introduced into the gas-liquid separator V-1 for gas-liquid separation. The separated ethylene is used as the recycled ethylene stream S-4, which is pressurized by compressor C-1 and recycled back to the reactor to be used together with fresh ethylene. The separated reaction liquid S-5 is the norbornene synthesis liquid.

[0089] (2-1) De-weighting: The reaction liquid S-5 obtained in step (1) is introduced into the de-weighting tower T-1 for the first distillation. The gaseous stream flowing out from the top of the tower enters the top condenser E-1 of the de-weighting tower for condensation. The non-condensable gaseous part enters the low-temperature condenser E-2 of the top of the de-weighting tower for low-temperature condensation. The norbornene in the stream is recovered and flows back to the top reflux tank of the de-weighting tower by gravity. The gaseous stream S-6 that is still not condensed at low temperature after passing through the low-temperature condenser E-2 is mainly composed of ethylene. Part of the stream condensed in the top condenser E-1 is returned to the top of the de-weighting tower, and the rest is collected as the top liquid stream S-7 of the de-weighting tower. This stream contains light components, norbornene and solvent. The bottom stream S-8 of the de-weighting tower containing heavy components such as dicyclopentadiene, tetracyclododecene and tricyclopentadiene is collected from the bottom of the tower. The theoretical number of plates in the deweight removal tower is 35, the number of feed plates is 17, the pressure at the top of the tower is 50 kPa, the temperature at the top of the tower is controlled at 45℃, the temperature at the bottom of the tower is 133℃, and the reflux ratio is 5.

[0090] Calculations show that the total amount of norbornene and toluene entering the bottom stream of the deweighting tower accounts for 0% and 1.74% of the total weight of norbornene and toluene in reaction solution S-5, respectively.

[0091] (2-2) Light Distillation: The overhead stream S-7 obtained in step (2-1) is introduced into the light distillation column T-2 for a second distillation. After condensation in condenser E-3, the overhead liquid stream S-10 containing cyclopentadiene is collected, the overhead non-condensable gas stream S-9 is collected, and the bottom stream S-11 containing norbornene and solvent is collected from the bottom of the column. The theoretical number of plates in the light distillation column is 30, the number of feed plates is 20, the top pressure is 110 kPa, the top temperature is 45℃, the bottom temperature is 108℃, and the reflux ratio is 30.

[0092] Table 1

[0093] Component logistics S-1 S-2 S-3 S-4 S-5 S-6 S-7 S-8 S-9 S-10 S-11 Logistics flow rate kg / h 159 100 259 121.32 137.68 28.40 104.28 5 0.27 1.73 102.28 Ethylene / wt.% 100.00 53.69 95.15 17.15 82.63 0.14 51.10 0.37 Cyclopentadiene / wt.% 0.10 0.04 0.15 0.41 0.08 8.41 3.79 0.05ppm Toluene / wt.% 50.00 19.31 1.51 34.98 2.32 44.75 16.73 22ppm 0.01 45.63 norbornene / wt.% 25.30 3.29 44.69 14.64 55.02 1ppm 40.49 95.83 54.37 Tetracyclododecene / wt.% 0.94 1.76 48.41 Dicyclopentadiene / wt.% 50.00 0.29 0.54 14.87 Tricyclopentadiene / wt.% 0.39 0.73 19.99

[0094] As shown in Table 1, norbornene was synthesized with high selectivity using a toluene solution of dicyclopentadiene and ethylene as raw materials. The heavy components were removed via a deweighting column. Although some toluene was carried in the bottom stream of the deweighting column, the amount of norbornene was very small. This carried toluene effectively reduced the bottom temperature of the column, preventing depolymerization or equipment blockage of heavy components such as dicyclopentadiene. The top stream of the deweighting column was used to remove light components. While the top stream contained a high concentration of norbornene, the actual flow rate was very small. The resulting norbornene solution contained only 0.05 ppm of cyclopentadiene, which is sufficient for COC synthesis.

[0095] Example 2

[0096] (1) The method in Example 1 was used, except that the amount of dicyclopentadiene solution S-2 and ethylene S-1 introduced was adjusted so that the molar ratio of dicyclopentadiene to ethylene entering reactor R-1 was 1:5. The remaining operations and conditions were the same as in Example 1, and the flow rate and composition of each step are detailed in Table 2.

[0097] Table 2

[0098] Component logistics S-1 S-2 S-3 S-4 S-5 S-6 S-7 S-8 S-9 S-10 S-11 Logistics flow rate kg / h 53 100 153 8.69 144.31 29.84 109.46 5 0.29 1.71 107.46 Ethylene / wt.% 100.00 21.60 95.13 17.18 82.53 0.14 50.25 0.37 Cyclopentadiene / wt.% 0.16 0.04 0.17 0.47 0.10 9.93 4.52 Toluene / wt.% 50.00 32.68 1.50 34.56 2.28 44.18 16.53 0.01 45.00 norbornene / wt.% 42.83 3.32 45.20 14.72 55.58 39.82 95.10 55.00 Tetracyclododecene / wt.% 1.58 1.68 48.48 Dicyclopentadiene / wt.% 50.00 0.49 0.52 14.99 Tricyclopentadiene / wt.% 0.65 0.69 20.00

[0099] (2) The method in Example 1 was used, except that the amount of dicyclopentadiene solution S-2 and ethylene S-1 introduced was adjusted so that the molar ratio of dicyclopentadiene to ethylene entering reactor R-1 was 1:50. The remaining operations and conditions were the same as in Example 1, and the flow rate and composition of each step are detailed in Table 3.

[0100] Table 3

[0101] Component logistics S-1 S-2 S-3 S-4 S-5 S-6 S-7 S-8 S-9 S-10 S-11 Logistics flow rate kg / h 530 100 630 515 115 29.84 109.46 5 0.29 1.71 107.46 Ethylene / wt.% 100.00 80.96 95.23 17.07 82.53 0.14 50.25 0.37 Cyclopentadiene / wt.% 0.04 0.03 0.10 0.47 0.10 9.93 4.52 Toluene / wt.% 50.00 7.94 1.58 36.41 2.28 44.18 16.53 21ppm 0.01 45.00 norbornene / wt.% 10.40 3.16 42.84 14.72 55.58 1ppm 39.82 95.10 55.00 Tetracyclododecene / wt.% 0.38 2.09 48.48 Dicyclopentadiene / wt.% 50.00 0.12 0.62 14.99 Tricyclopentadiene / wt.% 0.16 0.87 20.00

[0102] (3) The method in Example 1 was used, except that the concentration of the dicyclopentadiene solution was adjusted to 30% by weight. All other operations and conditions were the same as in Example 1. The flow rate and composition of each step are detailed in Table 4.

[0103] Table 4

[0104] Component logistics S-1 S-2 S-3 S-4 S-5 S-6 S-7 S-8 S-9 S-10 S-11 Logistics flow rate kg / h 159 166.7 325.7 106.84 218.86 42.98 170.88 5 0.48 4.52 168.88 Ethylene / wt.% 100.00 42.69 95.64 16.84 85.19 0.15 51.09 0.37 Cyclopentadiene / wt.% 0.08 0.03 0.10 0.29 0.06 8.44 3.81 Toluene / wt.% 70.01 35.83 2.22 52.24 3.92 65.43 16.63 0.0056 0.03 66.21 norbornene / wt.% 20.12 2.11 28.91 10.60 34.36 40.47 95.79 33.79 Tetracyclododecene / wt.% 0.74 1.11 48.44 Dicyclopentadiene / wt.% 29.99 0.23 0.34 14.93 Tricyclopentadiene / wt.% 0.31 0.46 20.00

[0105] (4) The method in Example 1 was used, except that the concentration of the dicyclopentadiene solution was adjusted to 60% by weight. All other operations and conditions were the same as in Example 1. The flow rate and composition of each step are detailed in Table 5.

[0106] Table 5

[0107] Component logistics S-1 S-2 S-3 S-4 S-5 S-6 S-7 S-8 S-9 S-10 S-11 Logistics flow rate kg / h 159 83.3 242.3 125.14 117.16 24.66 87.50 5 0.22 1.78 85.50 Ethylene / wt.% 100.00 57.39 94.93 17.29 81.66 0.14 51.20 0.37 Cyclopentadiene / wt.% 0.10 0.04 0.17 0.46 0.10 8.24 3.72 Toluene / wt.% 39.98 13.74 1.19 27.16 1.70 34.92 16.78 14ppm 69ppm 35.73 norbornene / wt.% 27.04 3.83 51.83 1.62 64.85 1ppm 40.56 95.91 64.26 Tetracyclododecene / wt.% 1.00 2.07 48.39 Dicyclopentadiene / wt.% 60.02 0.31 0.63 14.84 Tricyclopentadiene / wt.% 0.41 0.85 19.99

[0108] (5) The method in Example 1 was used, except that the solution was replaced with cyclohexane. All other operations and conditions were the same as in Example 1. The flow rate and composition of each step are detailed in Table 6.

[0109] Table 6

[0110] Component logistics S-1 S-2 S-3 S-4 S-5 S-6 S-7 S-8 S-9 S-10 S-11 Logistics flow rate kg / h 159 100 259 121.29 137.71 33.45 99.27 5 0.24 1.76 97.27 Ethylene / wt.% 100.00 53.69 93.51 18.62 76.32 0.11 42.97 0.36 Cyclopentadiene / wt.% 0.10 0.04 0.15 0.35 0.09 7.42 4.00 1ppm Cyclohexane / wt.% 50.00 19.31 3.21 33.48 13.89 41.77 18ppm 49.55 95.47 40.78 norbornene / wt.% 25.30 3.23 44.73 9.44 58.03 16.73 0.06 0.16 59.22 Tetracyclododecene / wt.% 0.94 1.76 48.40 Dicyclopentadiene / wt.% 50.00 0.29 0.54 14.87 Tricyclopentadiene / wt.% 0.39 0.73 19.99

[0111] (6) The method in Example 1 was used, except that the conversion rate of dicyclopentadiene in step (1) was controlled to 85% by controlling the reaction temperature at 220°C. The remaining operations and conditions were the same as in Example 1. The flow rate and composition of each step are detailed in Table 7.

[0112] Table 7

[0113] Component logistics S-1 S-2 S-3 S-4 S-5 S-6 S-7 S-8 S-9 S-10 S-11 Logistics flow rate kg / h 159 100 259 124.66 134.34 27.45 96.39 10.5 0.28 1.72 94.39 Ethylene / wt.% 100.00 54.69 95.33 16.98 82.60 0.14 47.03 0.35 Cyclopentadiene / wt.% 0.19 0.08 0.30 0.86 0.18 15.64 7.39 Toluene / wt.% 50.00 19.31 1.56 35.77 2.50 47.68 13.45 22ppm 0.011 48.69 norbornene / wt.% 22.27 2.98 40.18 14.03 52.00 1ppm 37.33 92.25 51.31 Tetracyclododecene / wt.% 0.35 0.00 0.68 8.64 Dicyclopentadiene / wt.% 50.00 2.90 0.06 5.53 70.77 Tricyclopentadiene / wt.% 0.29 0.56 7.14

[0114] (7) The method in Example 1 is adopted, except that the pressure at the top of the column for deweighting (2-1) is controlled at 100 kPa, the temperature at the top of the column is still 45°C, and the temperature at the bottom of the column is 161°C. The remaining operation and control conditions are the same as in Example 1. The flow rate and composition of each step are detailed in Table 8.

[0115] Table 8

[0116] Component logistics S-1 S-2 S-3 S-4 S-5 S-6 S-7 S-8 S-9 S-10 S-11 Logistics flow rate kg / h 159 100 259 121.32 137.68 25.65 107.03 5 0.73 1.27 105.03 Ethylene / wt.% 100.00 53.69 95.15 17.15 90.61 0.35 50.20 0.37 Cyclopentadiene / wt.% 0.10 0.04 0.15 0.29 0.12 10.02 4.57 Toluene / wt.% 50.00 19.31 1.51 34.98 1.24 43.92 16.73 19ppm 0.0095 44.76 norbornene / wt.% 25.30 3.29 44.69 7.86 55.61 7ppm 39.79 95.06 55.24 Tetracyclododecene / wt.% 0.94 1.76 48.41 Dicyclopentadiene / wt.% 50.00 0.29 0.54 14.87 Tricyclopentadiene / wt.% 0.39 0.73 19.99

[0117] (8) The method in Example 1 is adopted, except that the pressure at the top of the column for deweighting (2-1) is controlled at 80 kPa, the temperature at the top of the column is still 45°C, and the temperature at the bottom of the column is 151°C. The remaining operation and control conditions are the same as in Example 1. The flow rate and composition of each step are detailed in Table 9.

[0118] Table 9

[0119] Component logistics S-1 S-2 S-3 S-4 S-5 S-6 S-7 S-8 S-9 S-10 S-11 Logistics flow rate kg / h 159 100 259 121.32 137.68 26.36 106.32 5 0.55 1.45 104.32 Ethylene / wt.% 100.00 53.69 95.15 17.15 88.51 0.26 50.32 0.37 Cyclopentadiene / wt.% 0.10 0.04 0.15 0.33 0.11 9.79 4.46 Toluene / wt.% 50.00 19.31 1.51 34.98 1.52 44.14 16.73 20ppm 0.0099 44.98 norbornene / wt.% 25.30 3.29 44.69 9.63 55.49 4ppm 39.88 95.17 55.02 Tetracyclododecene / wt.% 0.94 1.76 48.41 Dicyclopentadiene / wt.% 50.00 0.29 0.54 14.87 Tricyclopentadiene / wt.% 0.39 0.73 19.99

[0120] Comparative Example 1

[0121] The method described in Example 1 was used, except that after step (2-2), the obtained norbornene solution (bottom stream S-11 of the light-removal tower) was further processed using the following method to remove toluene and obtain purified norbornene. The flow rates and compositions of each stream are detailed in Table 8.

[0122] The bottom stream S-11 from the light borneol removal column is introduced into the norborneol refining column for third distillation. The norborneol refining column has 30 theoretical plates, with the feed plate being the 20th (counting from top to bottom). The reflux ratio is 6. The norborneol stream S-12 is collected from the top of the column, and the toluene stream S-13 is collected from the bottom. The top flow rate is 55 kg / h, the top temperature is 94.7℃, the top pressure is 101 kPa, and the bottom temperature is 113.4℃. The flow rates and compositions of each stream are detailed in Table 10.

[0123] Table 10

[0124] Component logistics S-11 S-12 S-13 Logistics flow rate kg / h 102.28 55 47.28 Ethylene / wt.% Cyclopentadiene / wt.% 0.05ppm 0.09ppm Toluene / wt.% 45.63 0.84 97.73 norbornene / wt.% 54.37 99.16 2.27 Tetracyclododecene / wt.% Dicyclopentadiene / wt.% Tricyclopentadiene / wt.%

[0125] Calculations showed that, compared to Example 1, the method in Comparative Example 1 increased energy consumption. Under the operating conditions of Comparative Example 1, the condensing load at the top of the norbornene purification column alone was 33.6 kW, and the heating load of the reboiler at the bottom was 33.4 kW. The separated norbornene is a solid at room temperature, which easily clogs the condenser, reflux tank, and pipelines at the top of the distillation column. Furthermore, a large amount of solvent needs to be added to prepare a solution when the norbornene is used for subsequent COC polymerization.

[0126] This comparative example aims to illustrate that by employing the method provided by this invention to prepare norbornene, energy consumption can be significantly reduced, production costs decreased, and the production process simplified in the overall production process from norbornene synthesis and separation to COC synthesis. Although the purification step and energy consumption in this comparative example are redundant when using the method provided by this invention to synthesize norbornene using solvents that can be used in subsequent COC synthesis, existing technologies often use solvents that cannot be used in COC synthesis for norbornene synthesis. Such methods require solvent separation, leading to additional energy consumption, extended production processes, and higher production costs.

[0127] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A process for the low energy, short process preparation of norbornene, characterized in that, The method comprises: (1) Norbornene synthesis: introducing dicyclopentadiene and ethylene into a reactor in the presence of a solvent to react, to obtain a norbornene synthesis solution; wherein the reaction conditions are such that the conversion rate of dicyclopentadiene is not less than 90%; the solvent is an organic solvent that does not react in the reaction system; (2) Norbornene separation: separating the norbornene synthesis solution to remove light components and heavy components therefrom, to obtain a norbornene solution; wherein the norbornene solution contains norbornene and solvent, and the content of cyclopentadiene therein is not more than 100 ppm.

2. The method of claim 1, wherein, In step (1), the molar ratio of dicyclopentadiene to ethylene is 1:6-60, preferably 1:6-30; and / or, step (1) comprises formulating the solvent and dicyclopentadiene into a dicyclopentadiene solution, and introducing the dicyclopentadiene solution and ethylene into the reactor to react; Preferably, the amount of the solvent is such that the concentration of dicyclopentadiene in the dicyclopentadiene solution is 10-75% by weight, preferably 30-55% by weight; and / or, the solvent is selected from at least one of benzene, a benzene derivative having not more than 10 carbon atoms, a linear alkane or a cycloalkane having 5-10 carbon atoms; Preferably, the solvent is selected from at least one of benzene, toluene, xylene, cyclohexane, heptane, octane and decalin.

3. The method of claim 1, wherein, In step (1), the reaction conditions are such that the conversion rate of dicyclopentadiene is not less than 95%, preferably not less than 98%, more preferably not less than 99%; Preferably, the reaction conditions include: temperature 160-300℃, pressure 5-20 MPa; More preferably, the reaction conditions include: temperature 180-260℃, pressure 8-18 MPa; Preferably, step (1) further comprises a gas-liquid separation operation on the reaction product to recover unreacted ethylene.

4. The method of claim 1, wherein, In step (2), the content of cyclopentadiene in the norbornene solution is not more than 50 ppm, preferably not more than 10 ppm.

5. The method of claim 1 or 4, wherein, Step (2) comprises: (2-1) Heavy component removal: introducing the norbornene synthesis solution into a heavy component removal column to perform first distillation, to obtain a heavy component removal overhead stream containing light components, norbornene and solvent from the column top, and a heavy component removal bottom stream containing heavy components from the column bottom; wherein the conditions of the first distillation are such that the amount of norbornene and solvent entering the heavy component removal bottom stream is not more than 10% by weight of the amount of norbornene and solvent in the norbornene synthesis solution; (2-2) Light component removal: introducing the heavy component removal overhead stream obtained in step (2-1) into a light component removal column to perform second distillation, to obtain a light component removal overhead stream containing cyclopentadiene from the column top, and a norbornene separation solution containing norbornene and solvent from the column bottom.

6. The method of claim 5, wherein, In step (2-1), the theoretical plate number of the heavy component removal column is 20-55; Preferably, the conditions of the first distillation include: column top pressure 20-105 kPa, column top temperature 40-80℃; More preferably, the conditions of the first distillation further include: column bottom temperature 100-180℃, preferably 110-160℃; More preferably, the reflux ratio of the first distillation is 1-6, preferably 2-5.

7. The method of claim 6, wherein, In step (2-2), the theoretical plate number of the light component removal column is 15-50; Preferably, the conditions of the second rectification include: a column top pressure of 30-110 kPa, and a column top temperature of 45-100°C; More preferably, the conditions of the second rectification further include: a column bottom temperature of 75-110°C, preferably 80-110°C; More preferably, the reflux ratio of the second rectification is 10-35, preferably 20-30.

8. The method of any of claims 5-7, wherein, The method further includes: (2-3) Material recovery: recovering at least one of dicyclopentadiene, tetracyclododecene and solvent in the heavy-removing column bottom stream, and / or recovering cyclopentene and / or norbornene in the light-removing column top stream.

9. Use of the method according to any one of claims 1-8 in improving the quality of a cyclic olefin copolymer product.

10. A method of producing a high quality cyclic olefin copolymer, characterized by, The method includes: the raw material used in a cyclic olefin copolymer synthesis process includes a norbornene solution prepared according to the method of any one of claims 1-8. The method includes: the raw material used in a cyclic olefin copolymer synthesis process includes a norbornene solution prepared according to the method of any one of claims 1-8.

Images