Synthesis method of 2, 5-norbornadiene and cracking and addition reaction device of 2, 5-norbornadiene

Abstract

The invention relates to a synthesis method of 2, 5-norbornadiene and a cracking and addition reaction device of the 2, 5-norbornadiene, the device is characterized in that dicyclopentadiene is decomposed into cyclopentadiene at a high temperature, the cyclopentadiene is fully mixed in an acetone solvent and then fully contacted and reacted with diffused acetylene gas under the action of the addition reaction device, and the 2, 5-norbornadiene is obtained. Due to sufficient mixing and rapid reaction under a microscale, addition of dicyclopentadiene and cyclopentadiene, addition of dicyclopentadiene and acetylene and polymerization reaction of 2, 5-norbornadiene can be inhibited to a greater extent; unreacted cyclopentadiene is polymerized into dicyclopentadiene in a later process, so that recycling is facilitated; therefore, dangerous wastes are greatly reduced in the production process. A cracking device and an addition reaction device in the process are respectively formed by connecting four micro-channel assemblies and eight micro-channel assemblies in series. The method has the characteristics of high target product purity, high recovery rate, low reaction by-product content and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for preparing an organic compound and an apparatus thereof, in particular to a method for synthesizing 2,5-norbornadiene and an apparatus thereof for cracking and addition reaction. BACKGROUND

[0002] 2,5-norbornadiene (NBD) is a flammable liquid, which can be dissolved in petroleum ether and is insoluble in water, with a relative density of 0.909 (20℃) and a boiling point of 89℃. After full hydrogenation, 2,5-norbornadiene and its dimer can be used as high-energy fuel or main component of high-energy fuel for racing cars, missiles and rockets. The photoisomerization product of 2,5-norbornadiene is quadricyclane (QC), which is a high-energy fuel that can self-ignite. Moreover, the reversible photoisomerization reaction of 2,5-norbornadiene and quadricyclane can be used to absorb and release solar energy. Quadricyclane can also be used as a preservative to preserve flowers, fruits and vegetables. 2,5-norbornadiene is usually obtained by Diels-Alder addition of acetylene and cyclopentadiene. The existing preparation method of 2,5-norbornadiene is as follows:

[0003] Patent 1: The preparation method of 2,5-norbornadiene disclosed in US patent US2875256, which uses a continuous tubular reactor, the molar ratio of acetylene to cyclopentadiene is (1-10):1, the reaction temperature is 150-400℃, the reaction pressure is about 1.76 MPa, and the residence time of the material in the reaction zone is 1-15 minutes.

[0004] Patent 2: The preparation method of 2,5-norbornadiene disclosed in Chinese patent CN202110235986, which is to introduce acetylene into a mixing tank containing dicyclopentadiene and acetone at low temperature; use a constant flow pump to send the material to a continuous tubular reactor with an outer surface passivated acidic microporous zeolite catalyst at a fixed flow rate and maintain the temperature at 160-240℃ for reaction; collect the product after reaction and purify by rectification to obtain 2,5-norbornadiene.

[0005] Patent 3: The preparation method of 2,5-norbornadiene disclosed in Chinese patent CN200610117484.3, which uses a continuous tubular reactor and uses acetone as a solvent to dissolve dicyclopentadiene, the molar ratio of acetylene to dicyclopentadiene is (4.0-6.0):1, the weight ratio of acetone to dicyclopentadiene is (1.5-3.0):1, the reaction temperature is 180-200℃, and the residence time of the material in the tubular reactor is 10-30 minutes.

[0006] The above patents have low target product recovery rate and low product purity, and there are a large amount of 2,5-norbornadiene and cyclopentadiene reaction by-products in the product, and a large amount of cyclopentadiene trimer and polymer, which are harmful to the environment as hazardous waste. SUMMARY

[0007] The purpose of the present application is to improve the purity and recovery rate of the target product and reduce the reaction by-products by a synthesis method of 2,5-norbornadiene.

[0008] The purpose of the present application is achieved as follows:

[0009] A synthesis method of 2,5-norbornadiene, comprising the following steps:

[0010] (1) First, the preparation kettle is replaced with nitrogen, then the metered dicyclopentadiene and acetone are added to the preparation kettle in a weight ratio of 1:2-6 times, and the material temperature is reduced to -5- -20℃ under stirring, and acetylene gas is introduced to make the molar ratio of acetylene to acetone in the solution reach 0.75-0.85:1, and the reaction solution is prepared;

[0011] (2) The reaction material obtained in step (1) is continuously introduced into the cracking device by a constant flow pump, and dicyclopentadiene is fully cracked at 170-195℃ and a cracking pressure of 5-10 MPa, and the cracked material enters the rectification tower, and the rectification temperature is 78-80℃ and the reflux ratio is 3:1, and the rectified cyclopentadiene, acetone and acetylene gas enter the micro-flow field continuous reactor, i.e. addition reaction device, for reaction, and the reaction temperature is 180-220℃ and the reaction pressure is 7-8 MPa;

[0012] (3) After the reaction is completed, the excess acetylene gas is recycled to the acetylene gas circulation system, and the product is collected and purified by rectification to obtain finished product 2,5-norbornadiene with a purity of 99.5% or more.

[0013] In the above synthesis method of 2,5-norbornadiene, the material temperature in step (1) is reduced to -20℃ and acetylene gas is introduced, and the molar ratio of acetylene to acetone is 0.85:1; the cracking pressure in step (2) is 7-8 MPa, the cracking temperature is 170-175℃, the reaction pressure is 7-8 MPa, and the reaction temperature is 200-210℃; the yield of 2,5-norbornadiene is 92.5%, and the purity of the finished product is 88.5%.

[0014] Another purpose of the present application is to provide a cracking device and an addition reaction device used in the above synthesis method.

[0015] Another object of the present application is achieved in that a medium-pressure heating cracking device and an addition reaction device are composed of a plurality of micro-channel assemblies connected in series, each micro-channel assembly is structured as follows: two stainless steel or silicon carbide templates are provided with two rows of continuous S-shaped grooves with a surface diameter of 200-1000 μm and a heat conducting oil groove in the middle of the two rows of grooves etched on the surface of the templates, the two modules are buckled towards each other to form two rows of continuous S-shaped material flow channels and a heat conducting oil flow channel, and finally the two templates are clamped and fastened along the periphery of the two clamping plates by bolts; the connection mode of the plurality of micro-channel assemblies is as follows: the two material inlets of the first assembly are respectively connected with the outlets of a flow divider through stainless steel pipes, the inlet of the flow divider is used as the total material inlet, the two material outlets of the first assembly are respectively connected with the two material inlets of the second assembly through stainless steel pipes, the two material outlets of the second assembly are respectively connected with the two material inlets of the third assembly through stainless steel pipes, and the connection is performed in the same way until the two material outlets of the last assembly are respectively connected with the inlets of a flow combiner through stainless steel pipes, and the outlet of the flow combiner is used as the total material outlet; the heat conducting oil channels of the first assembly to the last assembly are connected in series through stainless steel pipes as the total heat conducting oil channel, and the material flow direction is opposite or the same as the heat conducting oil flow direction; the length of the material flow channel in each micro-channel assembly is controlled to be 2-4 m, and the total material flow channel length of the plurality of micro-channel assemblies is 10-20 m; the cracking pressure of the material is 7-8 MPa, and the cracking temperature is 180-200℃.

[0016] The addition reaction device is composed of 8 micro-flow channel assemblies: the total length of the material flow channels containing stainless steel pipes is 28 m, the length of a single micro-flow channel assembly not containing stainless steel pipes is 3.2 m, the diameter of the material flow channel is 320 μm, and the diameter of the heat conducting oil flow channel is 580 μm; all the stainless steel pipes are externally coated with thermal insulation materials; or the addition reaction device is composed of an oil bath disc tube with an inner diameter of 8 mm and a length of 40 m.

[0017] The medium-pressure heating cracking device is composed of 4 micro-flow channel assemblies: the total length of the material flow channels containing stainless steel pipes is 14.8 m, the length of a single micro-flow channel assembly not containing stainless steel pipes is 3.2 m, the diameter of the material flow channel is 320 μm, and the diameter of the heat conducting oil flow channel is 580 μm; all the stainless steel pipes are externally coated with thermal insulation materials.

[0018] Compared with the prior art, the present application has the following technical features and advantages:

[0019] 1. The core functional unit of the cracking device and addition reaction device is a structural module. A groove with an inner diameter of 200-1000 μm is etched on the surface of a stainless steel or silicon carbide plate by etching technology. The grooves of two plates are combined to form a flow channel. A heat exchange medium (heat conducting oil) channel is adjacent to the reaction flow channel. A "flow divider" is arranged at the material inlet end, and a "flow combiner" is arranged at the outlet end. The flow channel is a continuous S-shaped curved channel, which is beneficial to the mixing and mass transfer of the material by centrifugal force. The length of the single plate flow channel is controlled to be 2-4 m (too long will increase the processing difficulty), and the multiple plate integration is a total flow channel with a length of 10-20 m.

[0020] 2. In the synthesis process, dicyclopentadiene is used as the raw material, acetone is prepared, and acetylene gas is pumped into the cracking device under low-temperature stirring and pressure. Cracking is carried out at 7-8 MPa and 170-195°C. After cracking, the material is separated by rectification and then enters the addition reaction device to react with acetylene and cyclopentadiene. The target product has a purity of more than 99.5% and a recovery rate of up to 92.5% after rectification and purification.

[0021] 3. To solve the problem that the existing technology contains a large amount of by-products in the target product 2,5-norbornadiene, the present application decomposes dicyclopentadiene into cyclopentadiene at high temperature, fully mixes the cyclopentadiene in acetone solvent, and then makes it fully contact with diffused acetylene gas in the addition reactor. Due to the sufficient mixing and rapid reaction at a micro scale, the addition reactions of dicyclopentadiene and cyclopentadiene, dicyclopentadiene and acetylene, and 2,5-norbornadiene polymerization are inhibited to a large extent. The unreacted cyclopentadiene is polymerized into dicyclopentadiene in the later process, which is beneficial to recycling. Thus, the amount of hazardous waste is greatly reduced in the production process. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is the flowchart of the synthesis process of the present application.

[0023] Figure 2 is the schematic diagram of the material flow channel and the heat conducting oil flow channel of the cracking device and the addition reaction device.

[0024] Figure 3 is Figure 2 the partial enlarged view of the material flow channel and the heat conducting oil flow channel. DETAILED DESCRIPTION

[0025] Figure 3 In the figure, the continuous S-shaped material flow channel 1, 2, and the heat conducting oil flow channel 3.

[0026] Referring to Figure 2 , Figure 3A medium-pressure heating cracking device and an addition reaction device, the medium-pressure heating cracking device is composed of a plurality of micro-channel assemblies connected in series, each micro-channel assembly is structured as follows: two stainless steel or silicon carbide templates are etched on the surface of the plates to form two rows of continuous S-shaped grooves with a surface diameter of 200-1000 microns and a heat conducting oil groove in the middle of the two rows of grooves, the two modules are buckled together to form two rows of continuous S-shaped material flow channels and a heat conducting oil flow channel, and finally the two templates are clamped and fastened along the periphery of the two clamping plates to form the micro-channel assembly; the connection mode of the plurality of micro-channel assemblies is as follows: the two material inlets of the first assembly are respectively connected with the outlets of the flow divider through stainless steel pipes, the inlet of the flow divider is used as the total material inlet, the two material outlets of the first assembly are respectively connected with the two material inlets of the second assembly through stainless steel pipes, the two material outlets of the second assembly are respectively connected with the two material inlets of the third assembly through stainless steel pipes, and the connection is performed in the same way until the two material outlets of the last assembly are respectively connected with the inlets of the flow concentrator through stainless steel pipes, and the outlet of the flow concentrator is used as the total material outlet; the heat conducting oil channels of the first assembly to the last assembly are connected in series through stainless steel pipes as the total heat conducting oil channel, and the material flow direction is opposite or the same as the heat conducting oil flow direction; the length of the material flow channel in each micro-channel assembly is controlled to be 2-4 m, the total material flow channel length of the plurality of micro-channel assemblies is 10-20 m, the cracking pressure of the material is 7-8 MPa, and the cracking temperature is 180-200 DEG C.

[0027] The addition reaction device is composed of eight micro-flow channel assemblies: the total length of the material flow channel containing stainless steel pipes is 28 m, the length of a single micro-flow channel assembly not containing stainless steel pipes is 3.2 m, the diameter of the material flow channel is 320 microns, and the diameter of the heat conducting oil flow channel is 580 microns; all the stainless steel pipes are externally coated with thermal insulation materials; or the addition reaction device is composed of an oil bath disc tube with an inner diameter of 8 mm and a length of 40 m.

[0028] The medium-pressure heating cracking device is composed of four micro-flow channel assemblies: the total length of the material flow channel containing stainless steel pipes is 14.8 m, the length of a single micro-flow channel assembly not containing stainless steel pipes is 3.2 m, the diameter of the material flow channel is 320 microns, and the diameter of the heat conducting oil flow channel is 580 microns; all the stainless steel pipes are externally coated with thermal insulation materials.

[0029] The following examples are only used to make the purpose and technical solution of the present application clearer, and are not used to limit the present application. The reagents or instruments and equipment not specifically mentioned in the examples are conventional products that can be obtained by purchase.

[0030] Example 1:

[0031] Step one: the measured acetone and dicyclopentadiene are added into the reactor with stirring after nitrogen replacement, the temperature of the materials in the reactor is reduced to below -5°C under stirring, then acetylene is introduced, and the introduction of acetylene is stopped when the molar ratio of acetylene to acetone reaches 0.75:1.

[0032] Step two: the materials in step one are transported to the dicyclopentadiene cracker by a high-pressure constant-flow pump in a stable flow process; the temperature of the cracker is controlled at 170-175°C, the pressure is 5-6 MPa; the temperature at the top of the CPD rectifying column is 78-80°C, and the reflux ratio is 3:1.

[0033] Step three: the materials in step two enter the micro-flow field reactor under the action of pressure difference, and the Diels-Alder addition reaction of acetylene and cyclopentadiene is carried out in the micro-flow field reactor to generate 2,5-norbornadiene. The reaction pressure is 5-6 MPa, the reaction temperature is 180-190°C, and the target product 2,5-norbornadiene is obtained after the product is collected and purified by rectification.

[0034] Example 2:

[0035] Step one: the measured acetone and dicyclopentadiene are added into the reactor with stirring after nitrogen replacement, the temperature of the materials in the reactor is reduced to below -5°C under stirring, then acetylene is introduced, and the introduction of acetylene is stopped when the molar ratio of acetylene to acetone reaches 0.75:1.

[0036] Step two: the materials in step one are transported to the dicyclopentadiene cracker by a high-pressure constant-flow pump in a stable flow process; the temperature of the cracker is controlled at 170-175°C, the pressure is 5-6 MPa; the temperature at the top of the CPD rectifying column is 78-80°C, and the reflux ratio is 3:1.

[0037] Step three: the materials in step two enter the micro-flow field reactor under the action of pressure difference, and the Diels-Alder addition reaction of acetylene and cyclopentadiene is carried out in the micro-flow field reactor to generate 2,5-norbornadiene. The reaction pressure is 5-6 MPa, the reaction temperature is 180-190°C, and the target product 2,5-norbornadiene is obtained after the product is collected and purified by rectification.

[0038] Example 3:

[0039] Step one: the measured acetone and dicyclopentadiene are added into the reactor with stirring after nitrogen replacement, the temperature of the materials in the reactor is reduced to below -5°C under stirring, then acetylene is introduced, and the introduction of acetylene is stopped when the molar ratio of acetylene to acetone reaches 0.75:1.

[0040] Step two: the material of step one is transported to the dicyclopentadiene cracker by high-pressure constant flow pump with stable flow; the temperature of the cracker is controlled at 180-185℃, and the pressure is 6-7Mpa; the temperature at the top of the CPD rectifying column is 78-80℃, and the reflux ratio is 3:1.

[0041] Step three: the material of step two enters the micro-flow field reactor under the action of pressure difference, and the Diels-Alder addition reaction of acetylene and cyclopentadiene is carried out in the micro-flow field reactor to generate 2,5-norbornadiene. The reaction pressure is 6-7Mpa, and the reaction temperature is 180-190℃. After the reaction is completed, the product is collected and purified by rectification to obtain the target product 2,5-norbornadiene.

[0042] Example 4:

[0043] Step one: metered acetone and dicyclopentadiene are added to a stirred reaction kettle replaced with nitrogen, and the temperature of the material in the kettle is lowered to below -10℃ under stirring, then acetylene gas is introduced, and the molar ratio of acetylene to acetone is 0.8:1.

[0044] Step two: the material of step one is transported to the dicyclopentadiene cracker by high-pressure constant flow pump with stable flow; the temperature of the cracker is controlled at 185-190℃, and the pressure is 7-8Mpa; the temperature at the top of the CPD rectifying column is 78-80℃, and the reflux ratio is 3:1.

[0045] Step three: the material of step two enters the micro-flow field reactor under the action of pressure difference, and the Diels-Alder addition reaction of acetylene and cyclopentadiene is carried out in the micro-flow field reactor to generate 2,5-norbornadiene. The reaction pressure is 7-8Mpa, and the reaction temperature is 190-200℃. After the reaction is completed, the product is collected and purified by rectification to obtain the target product 2,5-norbornadiene.

[0046] Example 5:

[0047] Step one: metered acetone and dicyclopentadiene are added to a stirred reaction kettle replaced with nitrogen, and the temperature of the material in the kettle is lowered to below -20℃ under stirring, then acetylene gas is introduced, and the molar ratio of acetylene to acetone is 0.85:1.

[0048] Step two: the material of step one is transported to the dicyclopentadiene cracker by high-pressure constant flow pump with stable flow; the temperature of the cracker is controlled at 190-195℃, and the pressure is 7-8Mpa; the temperature at the top of the CPD rectifying column is 78-80℃, and the reflux ratio is 3:1.

[0049] Step three: the material of step two enters the micro-flow field reactor under the action of pressure difference, acetylene and cyclopentadiene carry out Diels-Alder addition reaction in the micro-flow field reactor to generate 2,5-norbornadiene. The reaction pressure is 7-8 Mpa, the reaction temperature is 200-210℃, and after the reaction is completed, the product is collected and purified by rectification to obtain the target product 2,5-norbornadiene.

[0050] Example 6:

[0051] Step one: metered acetone and dicyclopentadiene are added to the stirred reaction kettle after being replaced with nitrogen, the temperature of the material in the kettle is reduced to below -20℃ under stirring, then acetylene gas is introduced, and the introduction of acetylene is stopped when the molar ratio of acetylene to acetone reaches 0.85:1.

[0052] Step two: the material of step one is transported to the dicyclopentadiene cracker by a high-pressure constant-flow pump in a stable flow process; the cracker temperature is controlled at 170-175℃, the pressure is 7-8 Mpa; the CPD rectification column top temperature is controlled at 78-80℃, and the reflux ratio is 3:1.

[0053] Step three: the material of step two enters the micro-flow field reactor under the action of pressure difference, acetylene and cyclopentadiene carry out Diels-Alder addition reaction in the micro-flow field reactor to generate 2,5-norbornadiene. The reaction pressure is 7-8 Mpa, the reaction temperature is 200-210℃, and after the reaction is completed, the product is collected and purified by rectification to obtain the target product 2,5-norbornadiene.

[0054] Example 7:

[0055] Step one: metered acetone and dicyclopentadiene are added to the stirred reaction kettle after being replaced with nitrogen, the temperature of the material in the kettle is reduced to below -20℃ under stirring, then acetylene gas is introduced, and the introduction of acetylene is stopped when the molar ratio of acetylene to acetone reaches 0.85:1.

[0056] Step two: the material of step one is transported to the dicyclopentadiene cracker by a high-pressure constant-flow pump in a stable flow process; the cracker temperature is controlled at 170-175℃, the pressure is 7-8 Mpa; the CPD rectification column top temperature is controlled at 78-80℃, and the reflux ratio is 3:1. Step three: the material of step two enters the micro-flow field reactor under the action of pressure difference, acetylene and cyclopentadiene carry out Diels-Alder addition reaction in the micro-flow field reactor to generate 2,5-norbornadiene. The reaction pressure is 7-8 Mpa, the reaction temperature is 200-210℃, and after the reaction is completed, the product is collected and purified by rectification to obtain the target product 2,5-norbornadiene.

[0057] The above reflux ratio 3:1 means that 3 parts of material are taken out from the top of the rectification column, and 1 part is returned to the packing section of the column.

[0058] In each embodiment, the preparation temperature, pyrolysis temperature, synthesis temperature, and the molar ratio of acetone to acetylene were adjusted. The results are shown in the table below:

[0059]

[0060] illustrate:

[0061] The core functional unit of the pyrolysis and addition reaction units is the structural module. Grooves with an inner diameter of 200-1000 μm are etched into the surface of stainless steel or silicon carbide plates using etching technology. The grooves of two plates are merged to form a flow channel. Adjacent to the reaction flow channel is the heat exchange medium (heat transfer oil) channel. A "distributor" is installed at the material inlet and a "merger" at the outlet. The flow channel is a curved channel to facilitate enhanced mixing and mass transfer of the material through centrifugal force. The length of a single plate flow channel is controlled between 2 and 4 m. Multiple plates are integrated into a pyrolysis unit with a total flow channel of 10-20 m, or into an addition reaction unit with a total flow channel of 28 m.

[0062] In Examples 1-7, the microchannel components of the pyrolysis device and the addition reaction device are 4 and 8, respectively.

Claims

1. A medium-pressure heated pyrolysis apparatus and an addition reaction apparatus, characterized in that, The medium-pressure heated pyrolysis device consists of several microchannel components connected in series. Each microchannel component has two stainless steel or silicon carbide templates, each with two rows of continuous S-shaped grooves (200-1000 μm in diameter) etched into their surfaces using etching technology, and a heat-conducting oil groove located between the two rows of grooves. The two modules are interlocked to form two rows of continuous S-shaped material channels and one heat-conducting oil channel. Finally, two clamping plates are used to fasten the two templates together with bolts along their perimeter. The series connection of the microchannel components is as follows: the two material inlets of the first component are respectively screwed to the outlet of a distributor via stainless steel pipes. The inlet of the distributor serves as the main material inlet. The two material outlets of the first component are screwed to the two material inlets of the second component via stainless steel pipes. The two material outlets of the second component are screwed to the two material inlets of the third component via stainless steel pipes. This connection continues in the same manner until the two material outlets of the last component are connected to the inlet of the manifold via stainless steel pipes. The outlet of the manifold serves as the total material outlet. The heat transfer oil channels from the first component to the last component are sequentially connected end-to-end via stainless steel pipes to form the total heat transfer oil channel. The material flow direction is either opposite to or the same as the heat transfer oil flow direction. The length of the material flow channel in each microchannel component is controlled between 2 and 4 m, and the total material flow channel length of multiple microchannel components is 10 to 20 m. The material pyrolysis pressure is 7–8 MPa, and the pyrolysis temperature is 170–185℃. The addition reaction device consists of 8 microchannel components: the total length of the material flow channel including stainless steel tubes is 28m, the length of a single microchannel component without stainless steel tubes is 3.2m, the diameter of the material flow channel is 320μm, and the diameter of the heat transfer oil flow channel is 580μm; all the stainless steel tubes are covered with thermal insulation material; or, the addition reaction device consists of an oil bath coil with an inner diameter of 8mm and a length of 40m.

2. The medium-pressure heated pyrolysis apparatus and addition reaction apparatus according to claim 1, characterized in that, The medium-pressure heating pyrolysis device consists of four microchannel components: the total length of the material flow channel including the stainless steel tube is 14.8m, the length of a single microchannel component without the stainless steel tube is 3.2m, the diameter of the material flow channel is 320μm, and the diameter of the heat transfer oil flow channel is 580μm; all the stainless steel tubes are covered with heat insulation material.

3. A method for synthesizing 2,5-norbornadiene using the apparatus described in claim 1 or claim 2, characterized in that, Includes the following steps: (1) First, replace the preparation vessel with nitrogen gas, then add the measured dicyclopentadiene and acetone to the preparation vessel in a weight ratio of 1:2 to 6 times. Under stirring, lower the material temperature to -5 to -20℃ and introduce acetylene gas to make the molar ratio of acetylene to acetone in the solution reach 0.75 to 0.85:

1. The reaction solution is then prepared. (2) The reactants obtained in step (1) are continuously introduced into the cracking device through a constant flow pump. The dicyclopentadiene is fully cracked at 170-195°C and cracking pressure of 5-10 MPa. The cracked material enters the distillation column. The distillation temperature is 78-80°C and the reflux ratio is 3:

1. The distilled cyclopentadiene, acetone, and acetylene enter the micro-flow continuous reactor, i.e., the addition reaction device, for reaction at 180-220°C and 7-8 MPa. (3) After the reaction is completed, the excess acetylene gas is recovered into the acetylene gas circulation system. The product is collected and purified by distillation to obtain the finished product 2,5-norbornadiene with a purity of over 99.5%.

4. The method for synthesizing 2,5-norbornadiene according to claim 3, characterized in that, In step (1), the material temperature is lowered to -20℃ and acetylene gas is introduced, with a molar ratio of acetylene to acetone of 0.85:1; in step (2), the pyrolysis pressure is 7-8 MPa, the pyrolysis temperature is 170-175℃, the reaction pressure is 7-8 MPa, and the reaction temperature is 200-210℃; the yield of 2,5-norbornadiene is 92.5%, and the purity of the finished product is 88.5%.

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