Preparation method of exo-tetrahydrodicyclopentadiene

Abstract

The invention relates to the technical field of diene hydrogenation preparation, in particular to a preparation method of exo-tetrahydrodicyclopentadiene, which comprises the following steps of: performing catalytic hydrogenation on a dicyclopentadiene solution by using a circulating continuous flow bubbling hydrogenation reactor at the normal pressure and the temperature of 70-90 DEG C at the volume space velocity of 5h <-1 > and the hydrogen-oil volume ratio of 750-850 to obtain exo-tetrahydrodicyclopentadiene, automatically separating the hydrogenation catalyst at the tail end of the reactor to obtain a hydrogenation product, stirring and mixing an isomerization catalyst and the hydrogenation product at 90-110 DEG C, and carrying out catalytic isomerization to prepare exo-tetrahydrodicyclopentadiene; and rectifying and separating to obtain hanging tetrahydrodicyclopentadiene. According to the invention, the circulating continuous flow bubbling hydrogenation reactor is adopted for liquid phase hydrogenation, continuous production of exo-tetrahydrodicyclopentadiene is realized by a two-step method, the problem that catalytic hydrogenation and isomerization reaction are not matched is avoided, the conversion rate of exo-tetrahydrodicyclopentadiene is increased, and coking and impurity pollution of non-target products are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of diene hydrogenation, and particularly relates to a preparation method of exo-tetrahydrodicyclopentadiene. BACKGROUND

[0002] The exo-tetrahydrodicyclopentadiene has the advantages of high volumetric heat value, large density, good low-temperature performance (ice point is-79℃), etc., is widely used in high-performance cruise missiles, supersonic aircraft and rocket propellants, and can also be used as a solvent and mixed with other high-density hydrocarbon fuels, is the largest high-density liquid hydrocarbon fuel in the current utilization category. In addition, the exo-tetrahydrodicyclopentadiene is also an important chemical raw material in the fields of pharmaceutical industry, synthetic rubber, organic synthesis, etc., and the market demand prospect of the exo-tetrahydrodicyclopentadiene is good.

[0003] The exo-tetrahydrodicyclopentadiene (exo-THDCPD) is widely sourced and has a simple synthesis process, and is prepared by hydrogenation and isomerization of dicyclopentadiene in the C5 and C9 fractions of by-products of ethylene produced by petroleum cracking. First, the dicyclopentadiene is converted into endo-tetrahydrodicyclopentadiene (endo-THDCPD) by hydrogenation, and then the exo-tetrahydrodicyclopentadiene is generated by isomerization of the endo-tetrahydrodicyclopentadiene in the presence of a catalyst; after the reaction, the catalyst is removed, and high-purity exo-tetrahydrodicyclopentadiene is obtained by rectification.

[0004] In early studies, sulfuric acid and AlCl3 were used as catalysts to convert the end isomer of dicyclopentadiene into the exo isomer. However, there are several important disadvantages in using sulfuric acid and AlCl3 as catalysts, such as lack of selectivity, environmental problems, severe corrosion, difficulty in separation from the reaction mixture and waste treatment. Zeolites, heteropoly acids and mesoporous molecular sieves as alternatives to sulfuric acid and AlCl3 can solve some processing problems. Zeolites and heteropoly acids as catalysts require high processing temperatures of 195℃, 185℃ and 250℃. Such temperatures require higher energy consumption and can lead to the formation of by-products such as adamantane, heavier by-products and coke. Among them, the formation of coke reduces the service life of the catalyst. In addition, the formation of coke plays a key role in the deactivation of zeolite-type bifunctional catalysts, affecting the balance between the metal function and the acidity function of the catalyst.

[0005] Most of the reported hanging tetrahydrodicyclopentadiene in the prior art is intermittent, two-step synthesis. Wang Wei et al. (Wang Wei, Qu Yulong, Lv Jian, et al. One-step synthesis of hanging tetrahydrodicyclopentadiene [J]. Industrial Catalysis, 2007, 15:351-353) uses dicyclopentadiene as raw material, uses a fixed bed continuous reaction device for reaction, selects ReY, US-ReY, HY, Hβ, MCM-41 and Al2O3 as catalyst carrier, and prepares a nickel-loaded catalyst. The catalyst evaluation was carried out on the fixed bed, and the research showed that ReY was the best carrier, the loading amount of the catalyst nickel was 20% to 25%, and the selectivity was good. The optimal process conditions are: pressure 1 MPa, temperature 170℃, space velocity 5h-1, volume ratio of hydrogen to dicyclopentadiene 3, conversion rate reaches 100%, and the selectivity of exo-THDCPD reaches 55.7%.

[0006] It can be seen that when synthesizing exo-THDCPD by one-step method, the reaction efficiency is not matched, which leads to low selectivity of exo-THDCPD. In addition, the catalyst particles are densely packed in the existing fixed bed reaction device, which increases the fluid resistance and leads to significant pressure drop and high energy consumption. The accumulation of catalyst particles leads to blocked heat transfer, and local high temperature (hot spot) is easily formed, especially in exothermic reactions, the temperature distribution is uneven, which is more prominent, and is easy to cause coking pollution. In addition, the traditional fixed bed structure is difficult to realize online replacement of the catalyst, and the catalyst needs to be replaced by stopping operation, which affects the continuity of production.

[0007] Therefore, green development is the development trend of the petroleum and chemical industry. In view of the pollution and high cost problems in the current industrial synthesis of hanging tetrahydrodicyclopentadiene, how to realize green and economic synthesis of hanging tetrahydrodicyclopentadiene is a problem to be solved. SUMMARY

[0008] To solve the above technical problems, the present application provides a preparation method of hanging tetrahydrodicyclopentadiene, which relies on an improved hydrogenation reactor and uses a circulating continuous flow bubbling hydrogenation reactor for liquid phase hydrogenation, so that the hydrogenation depth and hydrogenation efficiency can be adjusted. The two-step method realizes continuous production of hanging tetrahydrodicyclopentadiene. In addition, the inventors improve the catalyst for isomerization reaction in the method, which improves the conversion rate. This technical scheme not only avoids the mismatch between catalytic hydrogenation and isomerization reaction, but also improves the conversion rate of hanging tetrahydrodicyclopentadiene, reduces coking and impurity pollution of non-target products, and realizes green and economic synthesis of hanging tetrahydrodicyclopentadiene.

[0009] The technical scheme adopted by the present application for solving the technical problem is as follows:

[0010] A preparation method of hanging tetrahydrodicyclopentadiene, comprising the following steps:

[0011] Step S1: catalytic hydrogenation, using a circulating continuous flow bubble hydrogenation reactor at atmospheric pressure, 70-90℃, with a volume space velocity of 5h -1 , a hydrogen oil volume ratio of 750-850, and a solution of dicyclopentadiene, wherein the solvent is 1,2-dichloroethane and the solute content is 20wt%-50wt%, to catalytically hydrogenate the dicyclopentadiene solution, and the hydrogenation catalyst is automatically separated at the end of the reactor to obtain a hydrogenation product;

[0012] Step S2: catalytic isomerization, using an isomerization catalyst to stir mix with the hydrogenation product obtained in step S1 at 90-110℃, to catalytically isomerize to prepare a hanging tetrahydrodicyclopentadiene;

[0013] Step S3: rectification separation to obtain a hanging tetrahydrodicyclopentadiene.

[0014] Further, the density of the hydrogenation catalyst is 1-1.05g / cm 3 , and the particle size of the hydrogenation catalyst is 40-80 mesh.

[0015] Further, the hydrogenation catalyst is 5% Pd / C, and the density is 1.025g / cm 3 .

[0016] Further, the dicyclopentadiene content in the dicyclopentadiene solution is 30wt%, and the amount of hydrogenation catalyst used is 4wt% of the dicyclopentadiene solution.

[0017] Further, the isomerization catalyst is a supported Pt catalyst.

[0018] Further, the preparation method of the supported Pt catalyst comprises the following steps:

[0019] Step A: hydrothermal calcination of molecular sieves at atmospheric pressure, 550℃ for 3h to obtain pretreated molecular sieves;

[0020] Step B: taking Pt(NH3)4Cl2 and the pretreated molecular sieves obtained in step A to prepare a co-precipitated molecular sieve catalyst by impregnation method;

[0021] Step C: taking the co-precipitated molecular sieve catalyst obtained in step B to dry at 70-90℃ for 10-20h to obtain a supported Pt catalyst.

[0022] Further, the loading amount of Pt on the supported Pt catalyst is 0.1wt%-0.5wt%, and the amount of the supported Pt catalyst used is 2-3wt% of the dicyclopentadiene solution.

[0023] Further, the supported Pt catalyst is calcined in air at 450℃ for 3h before use.

[0024] Further, the continuous flow bubbling hydrogenation reactor comprises a reaction chamber, the reaction chamber is externally provided with a jacket, the reaction chamber is internally coaxially connected with a partition pipe through a connecting piece, the partition pipe divides the space inside the reaction chamber into a bubbling space and a reflux space, the lower part of the reaction chamber is provided with a gas chamber below the partition pipe, the gas chamber is separated from the reaction chamber through a bubble distribution device, the upper part and the lower part of the bubble distribution device are respectively provided with a liquid material inlet communicating with the lower end of the partition pipe and a gaseous material inlet communicating with the gas chamber, the upper end of the reaction chamber is provided with an expansion zone above the partition pipe, and the upper end of the expansion zone is provided with a vent pipe and the middle part is provided with an overflow pipe.

[0025] Further, the inner end of the overflow pipe is bent downward after extending into the expansion zone, and the inner end of the overflow pipe is not higher than the upper end of the partition pipe.

[0026] Compared with the prior art, the beneficial effects of the present application are:

[0027] 1. The present application adopts continuous flow bubbling hydrogenation reaction and uses supported Pt to catalyze isomerization in series, and realizes continuous production of hanging tetrahydrodicyclopentadiene through a two-step method, so that the hydrogenation depth and hydrogenation efficiency can be adjusted, the hydrogenation reaction is matched with the isomerization reaction, the same diluent is used in the two-step method, so that separation is not needed in the production process, energy waste in the connection process between different processes is reduced, coking pollution is reduced, and green and economic synthesis of hanging tetrahydrodicyclopentadiene is realized.

[0028] 2. The present application provides a preparation method of a new type of isomerization catalyst for tetrahydrocyclopentadiene, which can reduce coking and impurity pollution problems.

[0029] 3. The present application provides an improved hydrogenation catalyst, which can realize liquid phase continuous hydrogenation process and equipment in the form of bubbling, can adjust the hydrogenation depth through liquid phase addition speed, and ensures conversion rate and reduces unnecessary energy waste. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a structural schematic diagram of the continuous flow bubbling hydrogenation reactor of the present application

[0031] In the figure: 1, outer cylinder; 2, jacket; 3, bubble distribution device; 4, gas chamber; 5, gaseous material inlet; 6, expansion zone; 7, vent pipe; 8, overflow pipe; 9, partition pipe; 10, bubbling space; 11, reflux space; 12, liquid material inlet. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with specific embodiments.

[0033] It should be noted that in the following examples, unless otherwise specified, are conventional methods.

[0034] The method for preparing the supported Pt catalyst comprises the following steps:

[0035] Step A: hydrothermally calcining the molecular sieve at 550°C under normal pressure for 3h to obtain a pretreated molecular sieve;

[0036] Step B: using the Pt(NH3)4Cl2 and the pretreated molecular sieve obtained in step A to prepare a co-precipitated molecular sieve catalyst by equal-volume impregnation;

[0037] Step C: drying the co-precipitated molecular sieve catalyst obtained in step B at 70-90°C for 10-20h to obtain the supported Pt catalyst.

[0038] The Pt loading is 0.1wt%-0.5wt%.

[0039] Example 1

[0040] A dicyclopentadiene solution with different mass concentrations in 1,2-dichloroethane was prepared.

[0041] A 5% Pd / C (40-80 mesh, density 1.025 g / cm 3 ) was added into the circulating continuous flow bubble hydrogenation reactor, and the Pd / C was added in an amount of 4% of the mass of the dicyclopentadiene solution in the circulating continuous flow bubble hydrogenation reactor. The dicyclopentadiene solution was catalytically hydrogenated at normal pressure and 90°C, with a volume space velocity of 5h -1 , a hydrogen / oil volume ratio of 700, and the hydrogenation catalyst was automatically separated at the end of the reactor to obtain the hydrogenation product. The solvent in the dicyclopentadiene solution was 1,2-dichloroethane, and the solute content was 20wt%-50wt%. The catalyst needed to be reduced at 500°C under H2for 3h before the reaction;

[0042] Step S2: using 0.5wt% supported Pt catalyst (amounting to 2% of the mass of the dicyclopentadiene solution) to catalytically isomerize the hydrogenation product obtained in step S1 at 110°C to prepare the exo-tetrahydrodicyclopentadiene;

[0043] Step S3: rectification separation to obtain the exo-tetrahydrodicyclopentadiene.

[0044] The reaction results are as follows:

[0045]

[0046] Example 2

[0047] A dicyclopentadiene solution with 30wt% in 1,2-dichloroethane was prepared.

[0048] The 5% Pd / C (40-80 mesh, density 1.025 g / cm 3 ) was added into the circulating continuous flow bubble hydrogenation reactor, and the amount of Pd / C was 4% of the mass of the dicyclopentadiene solution in the circulating continuous flow bubble hydrogenation reactor. The dicyclopentadiene solution was catalytically hydrogenated at normal pressure and 70°C, the volume space velocity was 5h -1 , the hydrogen / oil volume ratio was 850, 750, and 1000, respectively, the hydrogenation catalyst was automatically separated at the end of the reactor, and the hydrogenation product was obtained. The solvent in the dicyclopentadiene solution was 1,2-dichloroethane, and the solute content was 20wt%-50wt%. Before the reaction, the catalyst needed to be reduced at 500°C under H2for 3h.

[0049] Step S2: The 0.5wt% supported Pt catalyst (the amount was 4% of the mass of the dicyclopentadiene solution) was stirred and mixed with the hydrogenation product obtained in step S1 at 110°C to catalytically isomerize and prepare the exo-tetrahydrodicyclopentadiene.

[0050] Step S3: Distillation separation was performed to obtain the exo-tetrahydrodicyclopentadiene.

[0051] The reaction results are as follows:

[0052]

[0053] Example Three

[0054] A 1,2-dichloroethane solution containing 30wt% dicyclopentadiene was prepared.

[0055] The 5% Pd / C (40-80 mesh, density 1.025 g / cm 3 ) was added into the circulating continuous flow bubble hydrogenation reactor, and the amount of Pd / C was 4% of the mass of the dicyclopentadiene solution in the circulating continuous flow bubble hydrogenation reactor. The dicyclopentadiene solution was catalytically hydrogenated at normal pressure and 70°C, the volume space velocity was 5h -1 , 5h -1 , and 6h -1 , respectively, the hydrogen / oil volume ratio was 750, the hydrogenation catalyst was automatically separated at the end of the reactor, and the hydrogenation product was obtained. The solvent in the dicyclopentadiene solution was 1,2-dichloroethane, and the solute content was 20wt%-50wt%. Before the reaction, the catalyst needed to be reduced at 500°C under H2for 3h.

[0056] Step S2: The 0.5wt% supported Pt catalyst (the amount was 4% of the mass of the dicyclopentadiene solution) was stirred and mixed with the hydrogenation product obtained in step S1 at 110°C to catalytically isomerize and prepare the exo-tetrahydrodicyclopentadiene.

[0057] Step S3: Distillation separation was performed to obtain the exo-tetrahydrodicyclopentadiene.

[0058] The reaction results are as follows:

[0059]

[0060] Example Four

[0061] A 1,2-dichloroethane solution of 30wt% dicyclopentadiene was prepared.

[0062] A 5% Pd / C (density 1.025 g / cm 3 ) with a particle size of 40-80 mesh was added to the circulating continuous flow bubble hydrogenation reactor. The amount of Pd / C added was 4% of the mass of the dicyclopentadiene solution in the circulating continuous flow bubble hydrogenation reactor. The dicyclopentadiene solution was catalytically hydrogenated at normal pressure and 70°C, with a volume space velocity of 5h -1 , a hydrogen / oil volume ratio of 750, and the hydrogenation catalyst was automatically separated at the end of the reactor to obtain the hydrogenation product. The dicyclopentadiene solution had 1,2-dichloroethane as the solvent and a solute content of 20wt%-50wt%. The catalyst needed to be reduced at 500°C under H2for 3h before the reaction;

[0063] Step S2: The hydrogenation product obtained in step S1 was stirred and mixed with a 0.5wt% supported Pt catalyst (amounts of 2%, 2.5%, 3%, and 4% of the mass of the dicyclopentadiene solution) at 110°C to catalytically isomerize and prepare the hanging tetrahydrodicyclopentadiene.

[0064] Step S3: The hanging tetrahydrodicyclopentadiene was separated by rectification.

[0065] The reaction results are as follows:

[0066]

[0067] From the above examples, it can be seen that from Example One, the isomerization process has a slower reaction efficiency than the hydrogenation efficiency, so a lower substrate concentration is selected to have a smooth reaction process and reduce energy waste in the connection process between different processes. From Examples One, Two, and Four, when the isomerization catalyst ratio is higher, coking and non-target product impurities are easily produced, and the hydrogen / oil volume ratio during hydrogenation is 750-850 to achieve the hydrogenation target. From Examples One and Three, lower or higher material volume space velocities are not conducive to the reaction.

[0068] Therefore, under the catalytic action of a 5% Pd / C catalyst with a dosage of 4% and a 0.5wt% supported Pt catalyst, a raw material concentration of 20wt%-50wt%, a volume space velocity of 5h -1 , and a hydrogen / oil volume ratio of 750-850, a higher-purity hanging tetrahydrodicyclopentadiene can be obtained, and coking and impurity pollution during the reaction process can be reduced.

[0069] Example 5

[0070] like Figure 1 As shown, the circulating continuous flow bubbling hydrogenation reactor includes an outer cylinder 1, with a jacket 2 on the outside of the outer cylinder 1. The space inside the outer cylinder 1 is a reaction chamber. The jacket 2 is filled with heat-conducting oil for insulation and heating, promoting the reaction. A bubble distribution device 3 is provided at the lower part of the outer cylinder 1. The bubble distribution device 3 is made of commercially available microporous bubble distributors or microporous ceramic plates. The reaction chamber is above the bubble distribution device 3, and the gas chamber 4 is below it. The gas chamber 4 is connected to a gas supply device, which includes a nitrogen supply device for converting air and a hydrogen supply device for providing reaction gas. Both can be connected to the same gaseous material inlet. The outer cylinder 1 is a vertical tubular body with a [missing information - likely a design feature] at its upper end. The expansion zone 6 has a conical lower part and a dish-shaped upper part. The inner diameter of the expansion zone 6 is larger than the inner diameter of the lower tubular body. The upper end of the expansion zone is provided with a vent pipe 7. The middle part of the expansion zone 6 is connected to an overflow pipe 8. The inner end of the overflow pipe 8 extends into the expansion zone 6 and then extends downward to the lower end of the expansion zone 6. The outer cylinder 1 is coaxially connected to a separator pipe 9 via a connector. The upper end of the separator pipe 9 extends into the lower part of the expansion zone 6 and is not lower than the inner end of the overflow pipe 8. The lower end of the separator pipe 9 is close to the bubble distribution device 3. The space inside the separator pipe 9 is a bubble space 10. The space between the separator pipe 9 and the outer cylinder 1 is a reflux space 11. The lower end of the separator pipe 9 is connected to a liquid material inlet 12 for supplying dicyclopentadiene solution.

[0071] The method of using the circulating continuous flow bubbling hydrogenation reactor of the present invention is as follows: First, nitrogen is used to convert the air in the reactor. Then, hydrogen is supplied through the gaseous material inlet 5, and dicyclopentadiene solution is supplied through the liquid material inlet 12. The hydrogen is bubbled through the bubble distribution device 3, causing the dicyclopentadiene solution to circulate in the bubbling space 10 and the reflux space 11. The bubbling causes the dicyclopentadiene solution to carry the catalyst upward from the bubbling space 10. After reaching the expansion zone, because the flow cross-section becomes larger and there is no bubbling in the area outside the separator 9, the catalyst has no upward momentum and flows out through the reflux space 11 outside the separator 9. 1. Settles to the lower end of the reflux space 11, and is then carried upward along the bubbling space 10 by the bubbles generated by the bubble distribution device 3, forming a cycle. During this period, the heat transfer oil in the jacket 2 circulates to keep the temperature in the reactor uniform. The material flows due to bubbling, and the temperature transfer is rapid, which will not generate local high temperature, reduce coking problems and contamination by impurities and non-target products. After the cycle stabilizes, as the reactants are added, the liquid level gradually rises in the expansion zone and overflows out through the overflow pipe. The inner end of the overflow pipe is not higher than the upper end of the partition pipe, so it will not be flushed out by bubbling, ensuring that the catalyst does not enter the overflow pipe.

[0072] It is to be understood that the embodiments described herein are merely illustrative of the principles of this application and that numerous and various modifications can be effected thereto by those skilled in the art without departing from the spirit and scope of the application.

Claims

1. A method for preparing hanging tetrahydrodicyclopentadiene, characterized in that, Includes the following steps: Step S1: Catalytic hydrogenation, using a circulating continuous flow bubbling hydrogenation reactor at atmospheric pressure and 70-90°C, with a volume hourly space velocity of 5 h⁻¹. -1 Catalytic hydrogenation of dicyclopentadiene solution was carried out at a hydrogen-to-oil volume ratio of 750-850. The hydrogenation catalyst was automatically separated at the end of the reactor to obtain the hydrogenation product. The solvent in the dicyclopentadiene solution was 1,2-dichloroethane, and the solute content was 20wt%-50wt%. Step S2: Catalytic isomerization. The hydrogenation product obtained in step S1 is stirred and mixed at 90-110°C using an isomerization catalyst to prepare hanging tetrahydrodicyclopentadiene. Step S3: Distillation separation to obtain tetrahydrodicyclopentadiene. The density of the hydrogenation catalyst is 1-1.05 g / cm³. 3 The particle size of the hydrogenation catalyst is 40-80 mesh.

2. The method for preparing hanging tetrahydrodicyclopentadiene according to claim 1, characterized in that, The hydrogenation catalyst is 5% Pd / C with a density of 1.025 g / cm³. 3 .

3. The method for preparing hanging tetrahydrodicyclopentadiene according to claim 1, characterized in that, The dicyclopentadiene solution contains 30 wt% dicyclopentadiene, and the amount of hydrogenation catalyst used is 4 wt% of the dicyclopentadiene solution.

4. The method for preparing hanging tetrahydrodicyclopentadiene according to claim 1, characterized in that, The isomeric catalyst is a supported Pt catalyst.

5. The method for preparing hanging tetrahydrodicyclopentadiene according to claim 4, characterized in that, The preparation method of the supported Pt catalyst includes the following steps: Step A: The molecular sieve is hydrothermally calcined at 550℃ for 3 hours under normal pressure to obtain a pretreated molecular sieve; Step B: Take Pt(NH3)4Cl2 and the pretreated molecular sieve obtained in Step A, and prepare a coprecipitated molecular sieve catalyst by impregnation method; Step C: Dry the coprecipitated molecular sieve catalyst obtained in step B at 70-90℃ for 10-20h to obtain the supported Pt catalyst.

6. The method for preparing hanging tetrahydrodicyclopentadiene according to claim 5, characterized in that, The loading of Pt on the supported Pt catalyst is 0.1wt%-0.5wt%, and the amount of supported Pt catalyst used is 2wt%-3wt% of the dicyclopentadiene solution.

7. The method for preparing hanging tetrahydrodicyclopentadiene according to claim 4, characterized in that, The supported Pt catalyst was calcined in air at 450°C for 3 hours before use.

8. The method for preparing hanging tetrahydrodicyclopentadiene according to claim 1, characterized in that, The circulating continuous flow bubbling hydrogenation reactor includes a reaction chamber, which is equipped with a jacket (2) on the outside. A partition pipe (9) is coaxially connected to the inside of the reaction chamber via a connector. The partition pipe (9) divides the space inside the reaction chamber into a bubbling space (10) and a reflux space (11). A gas chamber (4) is located below the partition pipe (9) at the bottom of the reaction chamber. The gas chamber (4) is separated from the reaction chamber by a bubble distribution device (3). The bubble distribution device (3) is provided with a liquid material inlet (12) connected to the lower end of the partition pipe (9) and a gas material inlet (5) connected to the gas chamber (4) at the top and bottom, respectively. An expansion zone (6) is located above the partition pipe (9) at the top of the reaction chamber. A vent pipe (7) is provided at the top of the expansion zone (6) and an overflow pipe (8) is connected in the middle.

9. The method for preparing hanging tetrahydrodicyclopentadiene according to claim 8, characterized in that, The inner end of the overflow pipe (8) extends into the expansion area (6) and then bends downward. The inner end of the overflow pipe (8) is not higher than the upper end of the partition pipe (9).

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