A method and apparatus for preparing norbornene

Abstract

The application provides a preparation method and a preparation device of norbornene. First, ethylene is treated by spraying a solvent to form an ethylene solution, then the ethylene solution is mixed with dicyclopentadiene and enters a tower reactor, and in the tower reactor, the ethylene and the dicyclopentadiene undergo depolymerization reaction and D-A reaction to generate norbornene. The preparation method is easy to control, does not need a too complex process flow, and can effectively guarantee the yield and purity of the norbornene while reducing the production cost.

Description

Technical Field

[0001] This invention relates to norbornene, and more particularly to a method and apparatus for preparing norbornene, belonging to the field of cyclic olefin preparation technology. Background Technology

[0002] Norbornene (NB) is a cyclic olefin produced by diene synthesis (DA) of dicyclopentadiene (DCPD) and α-olefin. It can be used in the synthesis of cyclic olefin copolymers / polymer resins and has wide applications in optical lenses, pharmaceutical packaging and other fields.

[0003] Patent document CN104262074B discloses a process for producing norbornene using a gas-phase method. In this process, hydrogen, dicyclopentadiene vapor, and ethylene undergo a DA reaction in a fixed-bed reactor at a temperature of 300–320°C and a pressure of 10–30 MPa. Patent document CN118026798A discloses a process for synthesizing norbornene using a coupled heat exchange reactor. This process employs a solvent-liquid phase method, with a reaction temperature of 170–260°C and a reaction pressure reduced to 4–8 MPa.

[0004] However, in existing technologies, the synthesis of norbornene often requires high temperature and high pressure conditions, resulting in high equipment investment, significant safety risks, and insufficient yield. Therefore, how to reduce equipment investment while ensuring the yield and purity of norbornene in the production process has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] This invention provides a method for preparing norbornene. The preparation method is easy to control, does not require an overly complex process, reduces production costs, and effectively ensures the yield and purity of norbornene.

[0006] The present invention also provides an apparatus for preparing norbornene, which does not require expensive equipment such as compressors, and can realize the continuous and standardized production of norbornene, ensuring the yield and purity of norbornene.

[0007] This invention provides a method for preparing norbornene, comprising the following steps:

[0008] Ethylene is treated by spraying with a spraying solution to obtain an ethylene solution;

[0009] Dicyclopentadiene is mixed with the ethylene solution to carry out depolymerization and DA reaction to obtain norbornene.

[0010] The temperature of the spray treatment is not higher than 10°C.

[0011] In the preparation method described above, the spray liquid includes at least one of ethyl acetate, toluene, o-xylene, dichloropropane, and methyl isobutyl ketone.

[0012] In the preparation method described above, the mass ratio of the spray liquid to the ethylene is (1-4):1.

[0013] The preparation method described above, wherein the spraying treatment satisfies at least one of the following conditions:

[0014] 1) The flow rate of the spray liquid should be 10 to 15 times the flow rate of ethylene;

[0015] 2) The ethylene flow rate is 0.5~1.2 m / s;

[0016] 3) The pressure of the spray treatment is 10 kPaG~20 kPaG.

[0017] In the preparation method described above, the temperature of the depolymerization reaction is 160℃-180℃ and the pressure is 5MPaA-15MPaA; and / or, the temperature of the DA reaction is 180℃-200℃ and the pressure is 5MPaA-15MPaA.

[0018] In the preparation method described above, the molar ratio of ethylene to dicyclopentadiene is (1~5):1.

[0019] The preparation method described above, after the depolymerization reaction and the DA reaction are completed, further includes a process of separating the reaction solution, the separation process including:

[0020] The reaction solution is subjected to a first condensation treatment to obtain a condensate;

[0021] The condensate is flash-evaporated to separate vaporized vapor and unvaporized liquid.

[0022] The vaporized steam is subjected to a second condensation treatment to obtain norbornene.

[0023] Preferably, the temperature of the first condensation treatment is 50~80℃; and / or, the temperature of the flash evaporation treatment is 50-80℃ and the pressure is 1.1~5 bar; and / or, the temperature of the second condensation treatment is -10~30℃.

[0024] The preparation method described above further includes, in addition to, distilling the unvaporized liquid in a distillation column, and subjecting the light component separated from the top of the column to a third condensation treatment to obtain norbornene.

[0025] Preferably, the operating pressure of the distillation column is 60~100 kPa, the top temperature is 50~70℃, and the bottom temperature is 120~180℃; and / or, the temperature of the third condensation treatment is -10~30℃.

[0026] In another aspect, the present invention provides an apparatus for preparing norbornene, the apparatus being used to perform the preparation method described above;

[0027] The preparation apparatus includes a spraying unit, a mixing unit, and a reaction unit connected in sequence.

[0028] The preparation apparatus described above includes a tower reactor as the reaction unit and a spraying unit selected from a spraying tower or an absorption tower; the reaction unit comprises a first reaction unit and a second reaction unit.

[0029] The first reaction unit is used to carry out the depolymerization reaction;

[0030] The second reaction unit is used to carry out the DA reaction.

[0031] The preparation method provided by this invention allows gaseous ethylene to be directly absorbed by the spraying agent through spraying under certain temperature conditions. The operating conditions are mild and do not require high temperature and high pressure. Moreover, the reaction process between ethylene and dicyclopentadiene is a fully liquid phase reaction, which improves the mass transfer effect between ethylene and dicyclopentadiene, resulting in higher reaction conversion rate and norbornene selectivity, thus ensuring the yield and purity of norbornene. Attached Figure Description

[0032] Figure 1 This is a flowchart of a norbornene preparation apparatus provided in a specific embodiment of the present invention.

[0033] Explanation of reference numerals in the attached figures:

[0034] 1-Spraying unit, 2-Ethylene solution discharge unit, 3-Mixing unit, 4-Dicyclopentadiene feed unit, 5-Pressure unit, 6-Heating unit, 7-Reaction unit, 8-First condensation unit, 9-Flash evaporation unit, 10-Second condensation unit, 11-Distillation unit, 12-Reboiling unit, 13-Condenser, 14-Cold trap. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. 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.

[0036] In most existing processes, gaseous ethylene needs to be compressed before being fed into the reaction unit to react with dicyclopentadiene to produce norbornene. However, the compression process requires expensive compression equipment, which greatly increases the cost of production.

[0037] If ethylene can be reacted with dicyclopentadiene in liquid form at a lower cost, it would be of great significance for reducing production costs and improving economic efficiency.

[0038] This invention provides a method for preparing norbornene, comprising the following steps:

[0039] Ethylene is sprayed with a spray solution to obtain an ethylene solution; dicyclopentadiene is mixed with the ethylene solution to carry out depolymerization and DA reaction to obtain norbornene; the spraying temperature is not higher than 10℃.

[0040] In detail, the process involves contacting the spray liquid with ethylene at a temperature not exceeding 10°C, causing the ethylene to dissolve in the spray liquid and yielding an ethylene solution. It is understood that the spray liquid has a melting point below 10°C, a boiling point above 10°C, and does not react with ethylene.

[0041] The reason for controlling the spray treatment temperature to be no higher than 10°C is that the inventors discovered that when the temperature is no higher than 10°C, the kinetic energy of gaseous ethylene decreases, making it easier for it to be absorbed by the spray liquid, increasing the solubility of ethylene in the spray liquid, and improving the absorption efficiency; moreover, operating at a lower temperature can reduce the volatility of ethylene, improve the safety of operation, and reduce production costs.

[0042] To ensure sufficient contact between ethylene and the spraying liquid and further guarantee dissolution efficiency, the reverse contact between ethylene and the spraying liquid can be controlled to increase the contact area between them.

[0043] This invention does not limit the device used for spray treatment; common spray devices in the field, such as spray towers, can be selected according to the actual situation.

[0044] After obtaining the ethylene solution, dicyclopentadiene is mixed with the ethylene solution to obtain a raw material mixture, so that both dicyclopentadiene and ethylene are in solution. Under certain conditions, dicyclopentadiene undergoes a depolymerization reaction to generate cyclopentadiene. Cyclopentadiene and ethylene undergo a DA reaction under high temperature and high pressure to obtain norbornene.

[0045] The preparation method provided by this invention involves the direct absorption of gaseous ethylene by a spraying agent under specific temperature conditions. The operation is mild, requiring no high temperature or high pressure, resulting in lower costs. Furthermore, the reaction between ethylene and dicyclopentadiene is a fully liquid-phase reaction, leading to better mass transfer and higher reaction conversion and norbornene selectivity, thus ensuring the yield and purity of norbornene. Therefore, the preparation method of this invention can reduce production costs while effectively guaranteeing the yield and purity of norbornene.

[0046] To ensure the solubility of ethylene in the ethylene solution, in one specific embodiment, the spray solution includes at least one of ethyl acetate, toluene, o-xylene, dichloropropane, and methyl isobutyl ketone.

[0047] The above-mentioned spray solutions have high solubility for ethylene, can dissolve more ethylene, and provide sufficient raw material support for subsequent reactions. Moreover, the above-mentioned spray solutions have good chemical stability, are not prone to side reactions with ethylene, and can be recovered and reused from the ethylene solution through methods such as distillation, thereby improving the economic efficiency of production.

[0048] In one specific embodiment, the mass ratio of the spray liquid to ethylene is (1-4):1.

[0049] In detail, the mass ratio of spray liquid to ethylene in this invention refers to the mass ratio of spray liquid to ethylene in the reaction mixture after spray treatment. The ratio of spray liquid to ethylene includes, but is not limited to, 1:1, 2:1, 3:1, 4:1 or any combination thereof.

[0050] A higher proportion of spray liquid can increase the contact area and contact time between ethylene and the spray liquid, and can also prevent ethylene from being saturated in the spray liquid, thus affecting the amount of ethylene dissolved, and laying the foundation for providing sufficient ethylene in subsequent reactions.

[0051] Of course, parameters such as spray liquid flow rate, ethylene flow rate, and pressure during the spray treatment process will also have a certain impact on the spray effect. Appropriate parameters can increase the amount of ethylene dissolved. In one specific embodiment, the spray treatment meets at least one of the following conditions:

[0052] 1) The flow rate of the spray liquid should be 10 to 15 times the flow rate of ethylene;

[0053] 2) The ethylene flow rate is 0.5~1.2 m / s;

[0054] 3) The pressure of the spray treatment is 10 kPaG~20 kPaG.

[0055] Specifically, the flow rate of the spray liquid can be controlled by using an adjustable pump or valve, or a flow meter can be used to help detect and adjust the flow rate to the required range. The ratio of the spray liquid flow rate to the ethylene flow rate includes, but is not limited to, a range of 10, 11, 12, 13, 14, 15, or any combination thereof. An appropriate ethylene flow rate, such as 100 kg / h, can be selected based on actual conditions.

[0056] The ethylene flow rate can be monitored in real time using a flow rate sensor, and necessary adjustments can be made. The ethylene flow rate includes, but is not limited to, a range of 0.5 m / s, 0.6 m / s, 0.7 m / s, 0.8 m / s, 0.9 m / s, 1.0 m / s, 1.1 m / s, 1.2 m / s, or any combination thereof.

[0057] The pressure of the spray treatment is mainly monitored and controlled by pressure regulating valves and pressure sensors. The pressure of the spray treatment includes, but is not limited to, 10 kPaG, 12 kPaG, 14 kPaG, 16 kPaG, 18 kPaG, 20 kPaG, or any combination thereof.

[0058] The above conditions ensure sufficient contact between the spray solution and ethylene, promoting ethylene dissolution and increasing the amount of ethylene dissolved in the ethylene solution. It is understandable that the more conditions met, the higher the amount of ethylene dissolved, providing a more sufficient supply of ethylene for the subsequent reaction between ethylene and dicyclopentadiene.

[0059] In the reaction of ethylene with dicyclopentadiene, not only is a sufficient amount of raw material required, but also suitable reaction conditions need to be controlled. In one specific embodiment, the depolymerization reaction temperature is 160℃-180℃, and the pressure is 5MPaA-15MPaA; more specifically, the depolymerization reaction temperature includes, but is not limited to, a range of 160℃, 162℃, 164℃, 166℃, 168℃, 170℃, 172℃, 174℃, 176℃, 178℃, 180℃, or any two of these ranges; the pressure includes, but is not limited to, 5MPaA, 6MPaA, 8MPaA, 10MPaA, 12MPaA, 14MPaA, 15MPaA, or any two of these ranges.

[0060] When the temperature and pressure of the depolymerization reaction are within the above range, dicyclopentadiene can be depolymerized into cyclopentadiene as much as possible, while the temperature is not too high to allow cyclopentadiene to self-polymerize into oligomers such as dicyclopentadiene and tricyclopentadiene, which can effectively improve the efficiency of the depolymerization reaction.

[0061] In one specific embodiment, the temperature of the DA reaction is 180°C-200°C, and the pressure is 5 MPaA-15 MPaA; more specifically, the temperature of the depolymerization reaction includes, but is not limited to, 180°C, 182°C, 184°C, 186°C, 188°C, 190°C, 192°C, 194°C, 196°C, 198°C, 200°C, or any combination thereof; the pressure includes, but is not limited to, 5 MPaA, 6 MPaA, 8 MPaA, 10 MPaA, 12 MPaA, 14 MPaA, 15 MPaA, or any combination thereof.

[0062] The choice of temperature and pressure affects the activation energy and reactant stability of the DA reaction. Higher temperatures generally increase the reaction rate, while appropriate pressure can improve the mass transfer efficiency between ethylene and dicyclopentadiene, thus driving the reaction forward.

[0063] The temperatures of the depolymerization reaction and the DA reaction can be controlled within the above range by using a heat transfer medium. For example, the temperature of the heat transfer medium for the depolymerization reaction can be controlled at 175~190℃, and the temperature of the heat transfer medium for the DA reaction can be controlled at 195~215℃.

[0064] Before the depolymerization and DA reactions of the raw material mixture, in order to enable ethylene and dicyclopentadiene to react more fully, the raw material mixture can be subjected to pressure treatment and heating treatment.

[0065] In one specific embodiment, the raw material mixture is pressurized to 5~15MPaA, preferably 7~13MPaA; then the raw material mixture is heated to 100~180℃, preferably 100~150℃.

[0066] During the reaction, ethylene and dicyclopentadiene, as raw materials, need to be in a suitable ratio. In one specific embodiment, the molar ratio of ethylene to dicyclopentadiene is (1~5):1.

[0067] In this invention, the molar ratio of ethylene to dicyclopentadiene refers to the ratio of ethylene to dicyclopentadiene in the raw material mixture during the initial stage of the reaction. This ratio can be monitored using an online concentration detector, and may include the following steps: The online concentration detector is installed at the outlet pipe of the spray tower. Based on monitoring methods such as liquid capacitance or infrared radiation, the flow rate is adjusted via a controller. The molar ratio of ethylene to dicyclopentadiene is, but is not limited to, 1:1, 2:1, 3:1, 4:1, 5:1, or any combination thereof.

[0068] The reaction kinetics of ethylene and cyclopentadiene show that higher dicyclopentadiene concentrations lead to more side reactions (mainly self-polymerization), while higher ethylene concentrations result in fewer side reactions. However, higher ethylene concentrations require higher reaction pressures, which can cause ethylene precipitation and loss at higher reaction temperatures. When the molar ratio of ethylene to dicyclopentadiene is within the aforementioned range, ethylene loss can be effectively controlled, and the probability of side reactions can be reduced.

[0069] After ethylene and dicyclopentadiene react to obtain norbornene, both the raw materials and the product exist in the liquid phase. In one specific embodiment, after the depolymerization reaction and the DA reaction are completed, the reaction liquid is further separated. The separation process includes: performing a first condensation treatment on the reaction liquid to obtain a condensate.

[0070] Among them, the completion of the depolymerization and DA reactions can be determined by an online concentration detector. The value of the reaction solution after the reaction is completed can be tested in advance, and the reaction is considered to be completed if the value exceeds this value during production.

[0071] During the first condensation process, a suitable temperature can be selected. In one specific embodiment, the temperature of the first condensation process is 50~80℃.

[0072] Subsequently, the condensate was subjected to flash evaporation to separate vaporized vapor and unvaporized liquid.

[0073] During the flash evaporation process, appropriate temperature and pressure can be selected. Based on the boiling points of raw materials such as ethylene, dicyclopentadiene, and cyclopentadiene, in one specific embodiment, the flash evaporation temperature is 50-80℃ and the pressure is 1.1-5 bar.

[0074] After flash evaporation, the unreacted ethylene, as well as raw materials such as dicyclopentadiene and cyclopentadiene in the condensate, are separated from the liquid phase as vaporized steam, while the main component of the unvaporized liquid phase is norbornene.

[0075] The vaporized steam may also contain some norbornene. In order to improve the yield of norbornene, the vaporized steam can be subjected to a second condensation treatment to obtain norbornene.

[0076] The temperature during the second condensation process is -10~30℃.

[0077] The unvaporized liquid phase after flash evaporation and the components after the second condensation treatment constitute the product norbornene. In order to obtain norbornene with higher purity, the separation process also includes distilling the unvaporized liquid phase after flash evaporation and the components after the second condensation treatment in a distillation column, and performing a third condensation treatment on the light components separated at the top of the column to obtain norbornene.

[0078] The unvaporized liquid phase from the flash evaporation process and the components after the second condensation process may include norbornene, some spraying agents, residual dicyclopentadiene, and cyclopentadiene, among other substances.

[0079] The unvaporized liquid is distilled using a distillation column. Norbornene is mainly found in the light component separated at the top of the column. The light component is then subjected to a third condensation treatment to obtain norbornene.

[0080] The distillation column mainly produces the spray liquid. To improve the economic efficiency of the process, the spray liquid can be transported back to the spraying device through pipelines to participate in the spraying treatment and achieve recycling.

[0081] In the distillation process, it is necessary to control the appropriate temperature and pressure to achieve more precise separation between the components. The appropriate temperature and pressure are selected based on the boiling points of norbornene and the solvent. In one specific embodiment, the operating pressure of the distillation column is 60~100 kPa, the top temperature is 50~70°C, and the bottom temperature is 120~180°C; the temperature of the third condensation treatment is -10~30°C.

[0082] In another aspect, the present invention provides an apparatus for preparing norbornene, such as... Figure 1 As shown, the preparation apparatus is used to perform the preparation method described above;

[0083] The preparation apparatus includes a spraying unit 1, a mixing unit 3, and a reaction unit 7 connected in sequence.

[0084] The spray unit 1 includes an ethylene inlet, a spray liquid inlet, and an ethylene solution outlet. Ethylene enters the spray unit 1 through the ethylene inlet, and the spray liquid enters the spray unit 1 through the spray liquid inlet. In the spray unit 1, the ethylene and the spray liquid are in full contact, and part of the ethylene, which is in the gas phase, dissolves in the spray liquid to obtain an ethylene solution.

[0085] Mixing unit 3 includes an ethylene solution inlet, a dicyclopentadiene inlet, and a raw material mixture outlet. Ethylene solution enters mixing unit 3 through the ethylene solution outlet of spray unit 1 and the ethylene solution inlet of mixing unit 3. Dicyclopentadiene enters mixing unit 3 through the dicyclopentadiene inlet. In mixing unit 3, dicyclopentadiene dissolves in the ethylene solution to obtain the raw material mixture, providing a liquid phase environment for the subsequent reaction of ethylene and dicyclopentadiene.

[0086] Reaction unit 7 includes a raw material mixture inlet and a product outlet. The raw material mixture enters the reaction unit through the raw material mixture outlet of mixing unit 3 and the raw material mixture inlet of reaction unit 7. In the reaction unit, ethylene undergoes depolymerization and DA reaction with dicyclopentadiene to obtain norbornene.

[0087] In this invention, the device types of mixing unit 3 and reaction unit 7 are not limited. Common devices in the field can be selected according to actual conditions. For example, a raw material mixer can be selected for mixing unit 3 and a tower reactor can be selected for reaction unit 7.

[0088] like Figure 1 As shown, in order to promote the reaction, the preparation device may also include an ethylene solution discharge unit 2, a dicyclopentadiene feed unit 4, a pressurization unit 5, a heating unit 6, a first condensation unit 8, a flash evaporation unit 9, a second condensation unit 10, a distillation unit 11, and a third condensation unit 13.

[0089] In this process, the ethylene solution enters the ethylene solution discharge unit 2 through the ethylene solution outlet of the spray unit 1 and the inlet of the ethylene solution discharge unit 2. Under the pumping action of the ethylene solution discharge unit 2, it enters the mixing unit 3 and mixes with the dicyclopentadiene that enters the mixing unit 3 through the dicyclopentadiene feed unit 4 and the dicyclopentadiene inlet to obtain a raw material mixture. The raw material mixture enters the pressurization unit through the raw material mixture outlet of the mixing unit 3 and the inlet of the pressurization unit 5 for pressurization treatment. Subsequently, it enters the heating unit 6 through the outlet of the pressurization unit 5 and the inlet of the heating unit 6 for heating treatment. After heating treatment, the raw material mixture enters the reaction unit 7 through the raw material mixture inlet of the reaction unit 7 to undergo depolymerization and DA reactions.

[0090] After the depolymerization and DA reactions occur in reaction unit 7, the reaction liquid enters the first condensation unit 8 through the product outlet of reaction unit 7 and the inlet of the first condensation unit 8 for first condensation treatment. Subsequently, it enters the flash evaporation unit 9 through the outlet of the first condensation unit 8 and the inlet of the flash evaporation unit 9 for flash evaporation treatment. The gas phase after flash evaporation enters the second condensation unit 10 through the gas phase outlet for second condensation treatment. The liquid phase that has not been vaporized after flash evaporation enters the distillation unit 11 through the liquid phase outlet and the inlet of the distillation unit 11 for distillation treatment. During the distillation process, the light component separated from the top of the column enters the third condensation treatment unit for third condensation treatment to obtain norbornene. The spray agent separated in the column is transported back to the spray unit 1 through the pipeline for recycling. The heavy component byproduct is collected from the bottom of the column.

[0091] The heavy component byproducts collected from the bottom of the distillation column include entrained norbornene, tetracyclododecene, cyclopentadiene trimer, cyclopentadiene tetramer, and unreacted dicyclopentadiene. In one specific embodiment, a reboiling unit 12 is also included. The inlet of the reboiling unit 12 is connected to the bottom of the distillation unit 11, the gas phase outlet of the reboiling unit 12 is connected to the inlet of the distillation unit 11, and the liquid phase outlet of the reboiling unit 12 collects the heavy component byproducts. The specific type of reboiling unit 12, such as a reboiler, can be selected according to actual conditions.

[0092] In one specific embodiment, the third condensation processing unit includes a condenser 13 and a cold trap 14 connected in sequence.

[0093] The appropriate device type can be selected according to the actual situation. For example, the ethylene solution discharge unit 2 is selected as the ethylene solution discharge pump, the dicyclopentadiene feed unit 4 is selected as the dicyclopentadiene feed pump, the pressurization unit 5 is selected as the high pressure pump, the heating unit 6 is selected as the reaction preheater, the first condensation unit 8 is selected as the cooler, the flash evaporation unit 9 is selected as the flash tank, the second condensation unit 10 is selected as the cold trap, and the distillation unit 11 is selected as the distillation column.

[0094] When the second condensation unit 10 and the third condensation unit are equipped with cold traps, they can not only condense and recover the remaining norbornene, thus improving the yield of norbornene, but also effectively prevent pipeline blockage and improve production safety by utilizing the special structure of the cold traps.

[0095] The tailing phenomenon in the DA reaction is severe. It is basically impossible to use multiple reactors in series in a traditional batch reactor because the DA reaction requires high pressure conditions, has many weak points and leakage points, and the series connection of multiple reactors is very dangerous. In addition, the required reactor volume is very large, which greatly increases the production cost.

[0096] Furthermore, in a specific embodiment of the present invention, the reaction unit 7 is selected as a tower reactor, and the spraying unit is selected from a spraying tower or an absorption tower; the reaction unit 7 includes a first reaction unit and a second reaction unit; the first reaction unit is used to carry out the depolymerization reaction; the second reaction unit is used to carry out the DA reaction.

[0097] In one specific embodiment, the reaction unit 7 is a tower reactor, which is divided into two sections: the first section is the first reaction unit and the second section is the second reaction unit. Each section is equipped with a coil inside and a jacket outside.

[0098] In the first reaction unit, dicyclopentadiene undergoes a depolymerization reaction, breaking down into cyclopentadiene. This depolymerization reaction is endothermic, allowing for heating of the first reaction unit. In this case, the coil and jacket are used for heating. In the second reaction unit, ethylene and cyclopentadiene undergo a DA reaction, which is exothermic. The coil and jacket are used for exothermic reactions to prevent excessive side reactions caused by excessively high exothermic temperatures, which could affect the yield of norbornene.

[0099] In another specific embodiment, the reaction unit 7 further includes a third reaction unit. The reaction unit 7 is a tower reactor, which is divided into two sections: the first section is the first reaction unit, the second section is the second reaction unit, and the third section is the third reaction unit. Each section is equipped with a coil inside and a jacket outside.

[0100] In the third reaction unit, some unreacted cyclopentadiene and ethylene still exist in the raw material mixture. In the third reaction unit, coils and jackets are used for heat preservation. By extending the residence time of the raw material mixture in the reaction unit, the conversion rate is improved.

[0101] The present invention will be further described below through specific embodiments and comparative examples. Unless otherwise specified, the reagents, materials and instruments used below are all conventional reagents, materials and instruments, all of which are commercially available, and the reagents and materials involved can also be synthesized by conventional synthetic methods.

[0102] Example 1

[0103] The apparatus for preparing norbornene provided in this embodiment is as follows: Figure 1 As shown, it includes a spray tower 1, an ethylene solution discharge unit 2, a mixing unit 3, a dicyclopentadiene feed unit 4, a pressurizing unit 5, a heating unit 6, a reaction unit 7, a first condensation unit 8, a flash evaporation unit 9, a second condensation unit 10, a distillation unit 11, a reboiling unit 12, and a third condensation unit (including a condenser 13 and a cold trap 14).

[0104] The method for preparing norbornene provided in this embodiment includes the following steps:

[0105] Ethylene from the pipeline, at ambient temperature, enters from the bottom of spray tower 1 and is sprayed countercurrently with toluene entering from the top. The spraying temperature is 2℃, the ethylene flow rate is 100 kg / h, the spray liquid flow rate is 1500 kg / h, the ethylene velocity is 1 m / s, the contact time between the spray liquid and ethylene is 2 s, and the spraying pressure is 10 kPa. During this process, ethylene is absorbed by toluene, resulting in an ethylene solution. Part of the absorbed ethylene solution is used for recycling in the spray unit, and the rest is collected from the ethylene solution outlet of spray tower 1. Dicyclopentadiene is mixed with the ethylene solution in raw material mixer 3. The molar ratio of ethylene to dicyclopentadiene in the resulting raw material mixture is 4:1, the mass ratio of toluene to dicyclopentadiene is 3:1, and the mass ratio of toluene to ethylene is 2.4:1. The raw material mixture is pressurized to 12 MPa by high-pressure pump 5, then heated to 100℃ by heating unit 6 before entering tower reactor 7 for reaction. In the tower reactor, the feed liquid enters from bottom to top, undergoing a fully liquid-phase reaction. The tower reactor is divided into three sections: a first reaction unit, a second reaction unit, and a third reaction unit. In the first reaction unit, dicyclopentadiene mainly undergoes depolymerization, which is an endothermic reaction, and the reaction temperature in this section is controlled at 175°C. After entering the second section, the DA reaction occurs, which is an exothermic reaction, and the reaction temperature in this section is controlled at 195°C. In the third section, the reaction rate slows down, but it is still an exothermic reaction, and the reaction temperature is controlled at 200°C. The final NB reaction selectivity is 95%. The reaction liquid exiting the tower reactor 7 is first cooled to 50°C by the cooler 8, and then enters the flash tank 9 for depressurization. The pressure after depressurization is 3 bar, and unreacted ethylene gas and cyclopentadiene will flash out. At the same time, since a small amount of norbornene will be entrained in this gas phase, it needs to be captured by the cold trap 10, which has a temperature of 20°C. The flash-distilled liquid reaction mixture enters distillation column 11 for separation. Distillation column 11 is an atmospheric distillation column with a top temperature of 50℃ and a bottom temperature of 131℃. Norbornene product with a purity of 99.4% is collected from the top of the column, while toluene with a purity of 98% is collected from the middle and returned to the spray tower for recycling. Heavy byproducts are collected from the bottom of the column. The vapor phase exiting the condenser passes through cold trap 14 at 20℃ to capture norbornene, achieving a norbornene separation yield of 99.2%.

[0106] Example 2

[0107] The norbornene preparation apparatus provided in this embodiment is the same as that in Embodiment 1.

[0108] The method for preparing norbornene provided in this embodiment includes the following steps:

[0109] Ethylene from the pipeline, at ambient temperature, enters from the bottom of spray tower 1 and is sprayed in a countercurrent manner with toluene entering from the top at room temperature. The spraying temperature is 5℃, the ethylene flow rate is 120 kg / h, the spray liquid flow rate is 1300 kg / h, the ethylene velocity is 1 m / s, the contact time between the spray liquid and ethylene is 1.5 s, and the spraying pressure is 10 kPa. During this process, ethylene is absorbed by toluene, resulting in an ethylene solution. Part of the absorbed ethylene solution is used for the spray unit circulation, and part is collected from the ethylene solution outlet of spray tower 1. Dicyclopentadiene is mixed with the ethylene solution in raw material mixer 3. The molar ratio of ethylene to dicyclopentadiene in the resulting raw material mixture is 3:1, and the mass ratio of toluene to dicyclopentadiene is 3:1. The raw material mixture is pressurized to 10 MPa by high-pressure pump 5, and then heated to 100℃ by heating unit 6 before entering tower reactor 7 for reaction. In the tower reactor, the feed liquid enters from bottom to top and undergoes a full liquid-phase reaction. The tower reactor is divided into three sections, including a first reaction unit, a second reaction unit, and a third reaction unit. In the first reaction unit, dicyclopentadiene mainly undergoes a depolymerization reaction, which is an endothermic reaction. The reaction temperature in this section is controlled at 165°C. After entering the second section, a DA reaction occurs, which is an exothermic reaction. The reaction temperature in this section is controlled at 185°C. The reaction rate slows down in the third section, but it is still an exothermic reaction. The reaction temperature is controlled at 200°C. The final NB selectivity is 93%. The reaction liquid coming out of the tower reactor 7 is first cooled to 70°C by the cooler 8, and then enters the flash tank 9 for depressurization. The pressure after depressurization is 2 bar. Unreacted ethylene gas and cyclopentadiene will flash out. At the same time, since a small amount of norbornene will be entrained in this gas phase, it needs to be captured by the cold trap 10. The temperature of the cold trap is 20°C. The flash-distilled liquid reaction mixture enters distillation column 11 for separation. Distillation column 11 is a negative pressure distillation column with an internal pressure of 80 kPa, a top temperature of 50°C, and a bottom temperature of 118°C. Norbornene is collected from the top of the column with a purity of 99.4%, while toluene with a purity of 98% is collected from the middle of the column and returned to the spray tower for recycling. Heavy byproducts are collected from the bottom of the column. The vapor phase exiting the condenser passes through cold trap 14 at 20°C to capture norbornene, achieving a norbornene separation yield of 99.2%.

[0110] Example 3

[0111] The norbornene preparation apparatus provided in this embodiment is the same as that in Embodiment 1.

[0112] The method for preparing norbornene provided in this embodiment includes the following steps:

[0113] Ethylene from the pipeline, at ambient temperature, enters from the bottom of spray tower 1 and is sprayed in a countercurrent manner with toluene entering from the top at room temperature. The spray temperature is 7°C, the flow rate of the spray liquid is 1000 kg / h, the ethylene flow velocity is 1 m / s, the contact time between the spray liquid and ethylene is 1 s, and the spray pressure is 10 kPa. During this process, ethylene is absorbed by toluene, resulting in an ethylene solution. Part of the absorbed ethylene solution is used for recycling in the spray unit, and the other part is collected from the ethylene solution outlet of spray tower 1. Dicyclopentadiene is mixed with the ethylene solution in raw material mixer 3. The molar ratio of ethylene to dicyclopentadiene in the resulting raw material mixture is 2:1, and the mass ratio of toluene to dicyclopentadiene is 1.5:1. The raw material mixture is pressurized to 7 MPa by high-pressure pump 5, and then heated to 100°C by heating unit 6 before entering tower reactor 7 for reaction. In the tower reactor, the feed liquid enters from bottom to top and undergoes a full liquid-phase reaction. The tower reactor is divided into three sections, including a first reaction unit, a second reaction unit, and a third reaction unit. In the first reaction unit, dicyclopentadiene mainly undergoes a depolymerization reaction, which is an endothermic reaction. The reaction temperature in this section is controlled at 160°C. After entering the second section, a DA reaction occurs, which is an exothermic reaction. The reaction temperature in this section is controlled at 180°C. In the third section, the reaction rate slows down, but it is still an exothermic reaction. The reaction temperature is controlled at 200°C. The final NB selectivity is 90%. The reaction liquid coming out of the tower reactor 7 is first cooled to 50°C by the cooler 8, and then enters the flash tank 9 for depressurization. The pressure after depressurization is 2 barg. Unreacted ethylene gas and cyclopentadiene will flash out. At the same time, since a small amount of norbornene will be entrained in this gas phase, it needs to be captured by the cold trap 10. The temperature of the cold trap is 20°C. The flash-distilled liquid reaction mixture enters distillation column 11 for separation. Distillation column 11 is a negative pressure distillation column with an internal pressure of 60 kPa, a top temperature of 50°C, and a bottom temperature of 131°C. Norbornene is collected from the top of the column with a purity of 99.2%, while toluene with a purity of 98% is collected from the middle of the column and returned to the spray tower for recycling. Heavy byproducts are collected from the bottom of the column. The vapor phase exiting the condenser passes through cold trap 14 to capture norbornene at 10°C, achieving a norbornene separation yield of 99.2%.

[0114] 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 method for preparing norbornene, characterized in that, Includes the following steps: Ethylene is treated by spraying with a spraying solution to obtain an ethylene solution; Dicyclopentadiene is mixed with the ethylene solution to carry out depolymerization and DA reaction to obtain norbornene. The temperature of the spray treatment is not higher than 10°C.

2. The preparation method according to claim 1, characterized in that, The spray solution includes at least one of ethyl acetate, toluene, o-xylene, dichloropropane, and methyl isobutyl ketone.

3. The preparation method according to claim 1 or 2, characterized in that, The mass ratio of the spray liquid to the ethylene is (1-4):

1.

4. The preparation method according to any one of claims 1-3, characterized in that, The spraying treatment meets at least one of the following conditions: 1) The flow rate of the spray liquid should be 10 to 15 times the flow rate of ethylene; 2) The ethylene flow rate is 0.5~1.2 m / s; 3) The pressure of the spray treatment is 10 kPaG~20 kPaG.

5. The preparation method according to any one of claims 1-4, characterized in that, The depolymerization reaction is carried out at a temperature of 160℃-180℃ and a pressure of 5MPaA-15MPaA; and / or, the DA reaction is carried out at a temperature of 180℃-200℃ and a pressure of 5MPaA-15MPaA.

6. The preparation method according to any one of claims 1-5, characterized in that, The molar ratio of ethylene to dicyclopentadiene is (1~5):

1.

7. The preparation method according to any one of claims 1-6, characterized in that, After the depolymerization reaction and the DA reaction are completed, the process further includes separating the reaction solution, the separation process including: The reaction solution is subjected to a first condensation treatment to obtain a condensate; The condensate is flash-evaporated to separate vaporized vapor and unvaporized liquid. The vaporized steam is subjected to a second condensation treatment to obtain norbornene. Preferably, the temperature of the first condensation treatment is 50~80℃; and / or, the temperature of the flash evaporation treatment is 50-80℃ and the pressure is 1.1~5 bar; and / or, the temperature of the second condensation treatment is -10~30℃.

8. The preparation method according to claim 7, characterized in that, The separation process further includes distilling the unvaporized liquid in a distillation column and performing a third condensation process on the light components separated at the top of the column to obtain norbornene. Preferably, the operating pressure of the distillation column is 60~100 kPa, the top temperature is 50~70℃, and the bottom temperature is 120~180℃; and / or, the temperature of the third condensation treatment is -10~30℃.

9. An apparatus for preparing norbornene, characterized in that, The preparation apparatus is used to perform the preparation method according to any one of claims 1-8; The preparation apparatus includes a spraying unit, a mixing unit, and a reaction unit connected in sequence.

10. The preparation apparatus according to claim 9, characterized in that, The reaction unit is a tower reactor, and the spraying unit is selected from a spraying tower or an absorption tower. The reaction unit includes a first reaction unit and a second reaction unit; The first reaction unit is used to carry out the depolymerization reaction; The second reaction unit is used to carry out the DA reaction.

Images